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Business Complexity vs. Implementation Complexity

It is good software design practice to make sure that methods can be entirely viewed in the code editor that typically shows 30 to 45 lines at a time. The root of this principle is easy to grasp: scrolling up and down over a too large method impedes code readability.

Refactoring a too large method or a too large class implies to create several code elements smaller in terms of number of textual lines. But ultimately the code behavior didn’t change. In other words the business complexity remained the same but the refactor session reduced the implementation complexity (at least we hope so).

Software complexity is a subjective measure relative to the human cognition capabilities. Something is complex when it requires effort to be understood by a human. Software complexity is a 2 dimensional measure. To understand a piece of code one must understand both:

What this piece of code is doing at runtime, the behavior of the code, this is the business complexity.
How the actual implementation solves the business needs at runtime, this is the implementation complexity.

The whole point of software design, SOLID principles, code maintainability, patterns… is to avoid adding implementation complexity to the business complexity. But from where implementation complexity comes from? There are 5 main sources of implementation complexity:

Too Large Code

We already mentioned this one. It is easy to limit implementation complexity by abiding by simple code rules that check thresholds on code metrics like methods number of lines of code and method complexity, or classes with too many methods. The Single Responsibility Principle (SRP) also contribute to smaller implementations: less responsibilities for a class necessarily means less code.

Lack of Abstractions

An abstraction such as an abstract method, an interface or even a delegate, is the minimum required knowledged to invoke an implementation at runtime without knowing it at design time. In other words an abstraction hides implementation detail. Abstraction represents a great weapon to reduce the implementation complexity because polymorphism can replace quantity of if/else/switch/case. Concretely code like that:

void DrawShape(Shape shape) {
   switch(shape.Kind) {
      case ShapeKind.Circle: DrawCircle(shape); break;
      case ShapeKind.Rectangle: DrawRectangle(shape); break;
   }
}

void DrawShape(Shape shape) {

switch(shape.Kind) {

case ShapeKind.Circle: DrawCircle(shape); break;

case ShapeKind.Rectangle: DrawRectangle(shape); break;

}

Can be replaced with code like that:

void DrawShape(IShape shape) {
   shape.Draw();
}

void DrawShape(IShape shape) {

shape.Draw();

}

Abstraction also reduces implementation complexity because it frees the developer mind of implementation details.

The S in SOLID is the SRP (mentioned above) and is not related to abstraction. But the OLID principles are all about using abstractions wisely:

The Open-Close Principle (OCP) explains that an abstraction must remain stable with time, and thus must be designed carefully.
The Liskov Substitution Principle (LSP) explains that the quantity of knowledge presented by an abstraction must be enough to use it in all situations.
The Interface Segregation Principle (ISP) explains that an interface must be cohesive: methods that consume the interface typically use most of its members.
The Dependency Inversion Principle (DIP) explains that most dependencies in a system must point toward abstractions and not toward implementations.

How do we check for good usage of abstractions? There is no magic stick like thresholds to limit too large code elements. However the Abstractness vs. Instability graph and metrics and the Level metric are a good start to identify code areas that need more abstractions. They are both described in this post about Dependency Inversion Principle.

State Mutability at Runtime

A common source of implementation complexity is mutable states. The human brain is not properly wired to anticipate what is really happening at runtime in a program. While reviewing a class, it is hard to imagine how many instances will simultaneously exists at runtime and how the states of each these instances will evolve over time. This is actually THE major source of problems when dealing with a multi-threaded program.

If a class is immutable (if the states of all its instances objects don’t change at runtime once the constructor is called) its runtime behavior immediately becomes much easier to grasp and as a bonus, one doesn’t need to synchronize access to immutable objects. See here a post explaining in-depth immutable class.

A method is a pure function if it produces outputs from its inputs without modifying any state. Like immutable classes, pure functions are also a good mean to reduce implementation complexity.

Some code rules exists to enforce state mutability like Structure should be Immutable or Fields should be marked as ReadOnly when possible. Being immutable for a class or pure for a method is such an essential property that dedicated C# keywords for that would be welcome, like readonly for fields. Here is a proposal for C# support of the immutable keyword. By now some ImmutableAttribute or PureAttribute can be used to tag such elements and some code rule can check for Types tagged with ImmutableAttribute must be immutable or Methods tagged with PureAttribute must be pure

Over Coupling

When trying to re-engineer/understand/refactor a large piece of code (I mean something made of dozens of classes like a big namespaces or an assembly), the difficulty is directly proportional to the amount of coupling between considered code elements. Both dependency graphs below shows dependencies between 36 classes: but the left contains 64 edges and the right one contains 133 edges: which one would you prefer to deal with?

One key strategy to control coupling is to layer components and make sure that there is no dependency cycles. This can be checked on namespaces for example with the code rule Avoid namespaces dependency cycles. Using abstractions is also a good way to limit over coupling. If an interface has N implementations then relying only on one interface is virtually like depending on the N underlying classes.

Lack of Unit Tests

Software testing is a large topic I won’t cover here. But one key benefit of writing tests (apart enforcing business rules and detecting regressions early) is to ensure that the code is testable. Being testable for code means less coupling, more abstractions and overall simple code. Ultimately if the code is easily testable we can safely assume that its implementation complexity is kept low. Here also many code rules like Code should be tested can help enforce high testability.

One Measure for All

There are more sources of implementation complexity but those 5 ones are certainly the bigger culprits. To reduce this unnecessary complexity one must be able to measure it. But how to unify too large code, bad design, poorly tested code and more in a single metric?

As we saw most of these aspects can be enforced with code rules. A code rule produces issues and for each issue the code rule can estimate the cost to fix an issue and the annual cost to let an issue unfixed. A famous analogy with the financial field says that:

The estimated cost to fix code smells is the Technical-Debt: a measure of the implementation complexity.
The estimated annual cost to let code smells unfixed is the Annual Interest of the Debt: a measure of the business operation cost induced by poorly written and poorly tested code.

These estimations can be expressed in developer-time and ultimately in money cost which can be used by management to take the right decisions.

Answers to arguments against 100% coverage

I’ve been enthusiast about 100% coverage for more than a decade. The large code base of NDepend we are working on will reach soon 90% overall coverage. Most classes tested are being 100% covered.

In the heatmap below small rectangles are methods. Grapes of rectangles are classes namespaces and assemblies. By importing code coverage in this heat-map we can see at a glance that most classes are green: they are 100% covered. This heatmap also shows in red and orange areas with room for improvements. Areas in gray represent untestable code tagged with System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverageAttribute.

Not everybody agrees with 100% coverage and the same points against used to popup again and again so I take a chance to address them one by one.

I don’t waste my time writing tests to cover trivial code

Often the example of trivial code proposed is property getter and setter. Indeed writing tests to cover such get/set methods doesn’t bring any value. But such trivial code is meant to be used by real code, isn’t it?

For example suppose we have a Contact class with a property like Contact.FirstName, this properties is meant to be used. The module that builds an invoice and that prints the contact name on it certainly uses it. And if the build invoice module is well tested, Contact.FirstName must get called implicitly at test time.

So if some trivial code is not covered by tests, the idea is not to write dumb tests to cover it, the idea is to question yourself why the trivial code is not already implicitly covered by tests that exercise real code. And certainly you’ll find room for improvements in the tests suite in charge of testing the real code, that depends upon the trivial uncovered code. A future post will go through benefit of 100% coverage but as this point suggests, one key benefit is that a hole in 100% covered code is always an indicator of something interesting to improve.

90% coverage is enough

Often teams get satisfied with 90% or 95% coverage. For the scale of a large code base such score is outstanding. But for the scale of a class or a component 100% must be the goal.

The key is testability. We all have experienced some easy to test code and some hard to test code. The maintainability is hard to measure but the testability is something concrete. And good testability leads to good maintainability. In other words if a component can be fully tested seamlessly it means this component will be easy to maintain.

On the other hand, in the real world we often end up with a component that contains a small portion that is hard to test. And we get satisfied with 90 or 95% coverage. But this is sweeping dust under the carpet: this small portion of code is not testable because it is not well designed and as a consequence it is bug-prone. Hence we end up not testing the most sensitive part of the code that likely concentrates most of the problems!

If after having wrote a test suite you end up with a few if/else blocks that are hard to test, do a favor to yourself: refactor to reach seamless full testability.

What matters is what gets asserted in tests, not the amount of coverage

Suppose you have a 1.000 lines of code linear method: it only contains a linear list of processing with no if/then/switch/case… Suppose you have a test with zero assertions invoking this method. You end up with 1.000 lines of code 100% covered but not tested at all.

This fictitious situation often proposed as 100% coverage counter argument doesn’t reflect the reality. In the real world if one works hard to get a complex class 100% covered, I cannot imagine that the tests don’t contain an healthy amount of assertions. No matter if TDD Test First Design approach is used or if tests get written at the same time as code tested : writing tests leads to think more and to think better. One doesn’t write a test without having a few points in mind to assert.

But there is more. Why only tests should contain assertions? The code itself is well suited to contain assertions. For more than a decade we stuff the NDepend code base with assertions. Everything that can be asserted gets asserted. We end up with more than 26K assertions. A good half of those comes from non-nullable references. C#8 nullable reference will relieve all those assertions. But will remain all other assertions about non-empty strings, special string formats, non-zero counter, IDictionary.ContainsKey(), non-zero denominator of a division, !object.IsDisposed, loop invariant…. And all those assertions are checked at test time and fail tests when violated. Ultimately most tests end up with a 1/10 ratio between the number of assertions in test checked, and the number of assertions in code checked.

We still rely on the good old System.Diagnostics.Debug.Assert() but this is an implementation detail. Any assertion library can be used from the code itself (including a custom one, or the Code.Contracts library that would have deserved more love). The only thing that matters is to tune assertions to fail a test upon violation, typically by sending an exception. A related topic is if those assertions must be checked or not at production time. This is another interesting debate with pros and cons.

Some code just cannot be tested

Indeed there are some API call that just cannot be tested like calls to System.Windows.MessageBox. Such calls need to be mocked. This way the code is well splitted between 100% covered code and code tagged with System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverageAttribute. Dependency Injection can be used to inject untestable implementation in tested code.

Again testability is a central characteristic of code. Partitioning code according to its testability makes sense.

However, there are situations where such untestable API tend to prolifer. Then your choice is to either mock everything or accept to live with non-tested code. But being in this situation is the sign that such API is immature because not test-prone. Thus something radical must be done about that: get rid of it, contribute to it (if OSS), fork it…

UI Code is untestable

Since testing code has become a popular practice, UI code has always been treated as an awkward case: there are some frameworks dedicated to UI testing but such practice remains tedious and increases test maintenance. This is not satisfying.

As for any code, UI code must be written with testability in mind. UI code can contain UI logic but should not contain business logic. For example the UI class shouldn’t contain the implementation of a IsContactReadOnly() method (business logic) but can call such method declared in a non-UI testable class, to decide if a Contact First Name textbox should be readonly or editable (UI logic). Ideally UI code looks like an empty shell as much as possible.

Nowadays web development outperforms desktop developments. The backend spits HTML CSS and Javascript textual content. This content seen as data represents some easily testable material. However when possible, it is preferable to test the IsContactReadOnly() business logic directly from the backend code, than to test it indirectly, for example by checking if an HTML textbox is readonly or editable. Hopefully modern web platforms like ASP.NET Core propose testing strategies.

Desktop UI is a different beast to test and there is no magic. To test our UI specific code we’ve invested in an architecture where the UI code can be piloted, both from the main-form code and from tests. Such architecture relies massively on some mediator classes: any UI portion can pilot any other UI portion through these mediators. These mediators are used at production runtime, and tests supersede them to pilot the UI at testime. Tests dedicated to UI testing have few assertions, but such tests are not useless: they execute all the assertions stuffed in our UI code. At the end of the day some of our UI classes remain not fully covered but closed to. Small portions left untested doesn’t contain error-prone code but untestable UI peculiarities, like complex designer code or some DPI related code that can only be tested manually. The experience proved that this approach saved us from regression bugs many times.

100% coverage is a sensitive topic. In the NDepend team we are 100% coverage driven. In a future post we’ll detail the benefits of being 100% coverage driven. But I wanted to detail first the non-trivial reasons that make 100% coverage worth in most situations.

SOLID Design: The Dependency Inversion Principle (DIP)

After having covered the Open-Close Principle (OCP), the Liskov Substitution Principle (LSP), the Single Responsibility Principle (SRP) and the Interface Segregation Principle (ISP) let’s talk about the Dependency Inversion Principle (DIP) which is the D in the SOLID acronym. The DIP definition is:

a. High-level modules should not depend on low-level modules. Both should depend on abstractions.
b. Abstractions should not depend on details (concrete implementation). Details should depend on abstractions.

The DIP has been introduced in the 90s by Robert C Martin. Here is the original article.

A Dependency is a Risk

As all SOLID principles DIP is about system maintainability and reusability. Inevitably some parts of the system will evolve and will be modified. We want a design that is resilient to changes. To avoid that a change breaks too much, we must:

first identify parts of the code that are changes-prone.
second avoid dependencies on those changes-prone code portion.

The Liskov Substitution Principle (LSP) and the Interface Segregation Principle (ISP) articles explains that interfaces must be carefully thought out. Both principles are 2 faces of the same coin:

ISP is the client perspective: If an interface is too fat probably the client sees some behaviors it doesn’t care for.
LSP is the implementer perspective: If an interface is too fat probably a class that implements it won’t implement all its behaviors. Some behavior will end up throwing something like a NotSupportedException.

Efforts put in applying ISP and LSP result in interfaces stability. As a consequence these well-designed interfaces are less subject to changes than concrete classes that implement them.

Also having stable interfaces results in improved reusability. I am pretty confident that the interface IDisposable will never change. My classes can safely implement it and this interface is re-used all over the world.

In this context, the DIP states that depending on interfaces is less risky than depending on concrete implementations. DIP is about transforming this code:

static void ClientCode(SqlConnection sqlConnection) {
   sqlConnection.Open();
}

static void ClientCode(SqlConnection sqlConnection) {

sqlConnection.Open();

}

into this code:

static void ClientCode(IDbConnection dbConnection) {
   dbConnection.Open();
}

static void ClientCode(IDbConnection dbConnection) {

dbConnection.Open();

}

DIP is about removing dependencies from high-level code (like the ClientCode() method) to low-level code, low-level code being implementation details like the SqlConnection class. For that we create interfaces like IDbConnection. Then both high-level code and low-level code depend on these interfaces. The key is that SqlConnection is not visible anymore from the ClientCode(). This way the client code won’t be impacted by implementation changes, like when replacing the SQL Server RDBMS implementation with MySql for example.

Let’s underline that this minimal code sample doesn’t do justice to the word Inversion in the DIP acronym. The inversion is about interfaces introduced (to be consumed by high-level code) and implementation details: implementation details depends on the interfaces, not the opposite, here is the inversion.

DIP and Dependency Injection (DI)

The acronym DI is used for Dependency Injection and since it is almost the same as the DIP acronym this provokes confusion. The I is used for Inversion or Injection which might add up confusion. Hopefully DI and DIP are very much related.

DIP states that classes that implement interfaces are not visible to the client code.
DI is about binding classes behind the interfaces consumed by client code.

DI means that some code, external to client code, configures which classes will be used at runtime by the client code. This is simple DI:

static void DICode() {
   IDbConnection dbConnection = new SqlConnection();
   ClientCode(dbConnection);
}
static void ClientCode(IDbConnection dbConnection) { // Client code has no idea what's behind IDbConnection
   dbConnection.Open();
}

static void DICode() {

IDbConnection dbConnection = new SqlConnection();

ClientCode(dbConnection);

}

static void ClientCode(IDbConnection dbConnection) { // Client code has no idea what's behind IDbConnection

dbConnection.Open();

}

Many .NET DI frameworks exist to offer flexibility in binding classes behind interfaces. Those frameworks are based on reflection and thus, they offer some kind of magic. The syntax looks like:

   // Autofac DI
   var builder = new ContainerBuilder();
   builder.RegisterInstance(new SqlConnection()).As<IDbConnection>();
   
   // UnityContainer DI
   IUnityContainer container = new UnityContainer();
   container.RegisterType<IDbConnection, SqlConnection>();
   
   // NInject DI
   public class Bindings : NinjectModule {
      public override void Load() {
         Bind<IDbConnection>().To<SqlConnection>();
      }
   }

// Autofac DI

var builder = new ContainerBuilder();

builder.RegisterInstance(new SqlConnection()).As<IDbConnection>();

// UnityContainer DI

IUnityContainer container = new UnityContainer();

container.RegisterType<IDbConnection, SqlConnection>();

// NInject DI

public class Bindings : NinjectModule {

public override void Load() {

Bind<IDbConnection>().To<SqlConnection>();

}

And then comes what is called a Service Locator. The client can use the locator to create instances of the concrete type without knowing it. It is like invoking a constructor on an interface:

IDbConnection dbConnection = Locator.Resolve<IDbConnection>();

1	IDbConnection dbConnection = Locator.Resolve<IDbConnection>();

Thus while DIP is about maintainable and reusable design, DI is about flexible design. Both are very much related. Let’s notice that the flexibility obtained from DI is especially useful for testing purposes. Being DIP compliant improves the testability of the code:

class MockConnection : IDbConnection {
   void Open() { ... }
   ...
}
[Test]
public void MyTest() {
   IDbConnection dbConnection = new MockConnection(); // Abstract the test from the database layer
   var result = ClientCode(dbConnection);
   Assert.ThingsOn(result);
}
static Result ClientCode(IDbConnection dbConnection) {
   dbConnection.Open();
   // ... do interesting stuff
   return result;
}

class MockConnection : IDbConnection {

void Open() { ... }

...

}

[Test]

public void MyTest() {

IDbConnection dbConnection = new MockConnection(); // Abstract the test from the database layer

var result = ClientCode(dbConnection);

Assert.ThingsOn(result);

}

static Result ClientCode(IDbConnection dbConnection) {

dbConnection.Open();

// ... do interesting stuff

return result;

}

DIP and Inversion of Control (IoC)

The Inversion word is used both in DIP and IoC acronyms. This provokes confusion. Remember that the word Inversion in the DIP acronym is about implementation details depending on interfaces, not the opposite. The Inversion word in the IoC acronym is about calls to Library transformed into callbacks from Framework.

IoC is what differentiates a Framework from a Library. A library is typically a collection of functions and classes. On the other hands a framework also offers reusable classes but massively relies on callbacks. For example UI frameworks offers many callback points through graphical events:

class MyForm : FrameworkForm {
   private Button m_Button = new Button();
   public MyForm() {
      m_Button.OnClick += m_ButtonOnClick;
   }
   private void m_ButtonOnClick(Sender sender) { ... }
}

class MyForm : FrameworkForm {

private Button m_Button = new Button();

public MyForm() {

m_Button.OnClick += m_ButtonOnClick;

}

private void m_ButtonOnClick(Sender sender) { ... }

}

The method m_ButtonOnClick() bound to the Button.OnClick event is a callback method. Instead of client code calling a framework method, the framework is responsible for calling back client code. This is an inversion in the control flow.

We can see that IoC is not related to DIP. However we can see Dependency Injection has a specialization of IoC: DI is an IoC used specifically to manage dependencies.

DIP and the Level metric

Several code metrics can be used to measure, and thus constraint, the usage of DIP. One of these metric is the Level metric. The Level metric is defined as followed:

From this diagram we can infer that:

The Level metric is not defined for components involved in a dependency cycle. As a consequence null values can help tracking component dependency cycles.
The Level metric is defined for any dependency graph. Thus a Level metric can be defined for various granularity: methods, types, namespaces, assemblies.

DIP mostly states that types with Level 0 must be interfaces and enumerations (note that interfaces using others interfaces have a Level value higher than 0). If we say that a component is a group of types (like a namespace or an assembly) the DIP states that components with Level 0 must contain mostly interfaces and enumerations. With a quick code query like this one you can have a glance at types Level and check if most of low level types are interfaces:

from t in JustMyCode.Types
where t.Level != null
orderby t.Level ascending
select new { t, t.Level }

from t in JustMyCode.Types

where t.Level != null

orderby t.Level ascending

select new { t, t.Level }

The Level metric can also be used to track classes with high Level values: it is a good indication that some interfaces must be introduced to break the long chain of concrete code calls:

The class Program has a Level of 8 and if we look at the dependency graphs of types used from Program we can certainly see opportunities to introduce abstractions to be more DIP compliant:

DIP and the Abstractness vs. Instability Graph

Robert C. Martin not only coined the DIP but also proposed some code metrics to measure the DIP compliance. See these metrics definitions here. From these metrics an intriguing Abstractness vs. Instability diagram can be plotted. Here we plotted the 3 assemblies of the OSS eShopOnWeb application. This diagram has been obtained from an NDepend report:

The Abstractness metric is normalized : it takes its values in the range [0,1]. It measures the interfaces / classes ratio (1 means the assembly contains only interfaces and enumerations).
The Instability metric is normalized and measures the assembly’s resilience to change. In this context, being stable means that a lot of code depends on you (which is wrong for a concrete class and fine for an interface) and being unstable means the opposite: not much code depends on you (which is fine for a concrete class and wrong for an interface, a poorly used interface is potentially a waste of design efforts).

This diagram shows a balance between the two metrics and defines some green/orange/red zones:

A dot in the red Zone of Pain means that the assembly is mostly concrete and used a lot. This is a pain because all those concrete classes will likely undergo a lot of changes and each change will potentially impact a lot of code. An example of a class living in the Zone of Pain would be the String class. It is massively used but it is concrete: if a change should occur today in the String class the entire world would be impacted. Hopefully we can count on the String implementation to be both performance-wise and bug-free.
A dot in the red Zone of Uselessness means that the assembly contains mostly interfaces and enumerations and is not much used. This makes these abstractions useless.
The Green zone revolves around the Main Sequence line. This line represents the right balance between both metrics. Containing mostly interfaces and being used a lot is fine. Containing mostly classes and not being used much is fine. And then comes all intermediate well balanced values between these 2 extremes represented by the Main Sequence line. The Distance from Main Sequence metric can be normalized and measures this balance. A value close to 0 means that the dot is near the line, in the green zone, and that the DIP is respected.

Conclusion

As the Open-Close Principle (OCP), the Liskov Substitution Principle (LSP) and the Interface Segregation Principle (ISP) the DIP is a key principle to wisely harness the OOP abstraction and polymorphism concepts in order to improve the maintainability, the reusability and the testability of your code. No principle is an island (except maybe the Single Responsibility Principle (SRP)) and they must be applied hands-in-hands.

This article concludes this SOLID posts serie. Being aware of SOLID principles is not enough: they must be kept in mind during every design decision. But they also must be constrained by the KISS principle, Keep It Simple Stupid, because as we explained in the post Are SOLID principles Cargo Cult? it is easy to write entangled code in the name of SOLID principles. Then one can learn from experience. With years, identifying the right abstractions and partitioning properly the business needs in well balanced classes is becoming natural.

SOLID Design: The Interface Segregation Principle (ISP)

After having covered The Open-Close Principle (OCP), The Liskov Substitution Principle (LSP) and the Single Responsibility Principle (SRP) let’s talk about the Interface Segregation Principle (ISP) which is the I in the SOLID acronym. The ISP definition is:

Client should not be forced to depend on methods it does not use.

It is all about interface, the common abstractions available in most OOP language such as C#, VB.NET or Java. A more complete and actionable explanation of ISP is:

ISP splits interfaces that are very large into smaller and more specific ones so that clients will only have to know about the methods that are of interest to them. Such shrunken interfaces are also called role interfaces.

Roles and Responsibilities

When a class implements several shrunken role interfaces, it has several roles which might lead to think that such class has several responsibilities: it would then violate the Single Responsibility Services.

But a role is a finer-grained concept than a responsibility. An example of a role is the IDisposable interface:

public interface IDisposable {
   void Dispose();
}

public interface IDisposable {

void Dispose();

}

This interface has a single method but it is implemented by a wide variety of classes: DB or network connections that need to be closed gracefully, UI elements that need to deallocate some bitmaps in memory… The only thing the IDisposable interface says to clients is that instances of IDisposable class needs a graceful shutdown.

Hence IDisposable represents a technical detail that the client needs to be aware of. It is much finer-grained concept than a responsibility.

A small interface is not necessarily a good abstraction

A single method interface often makes sense, an IExecutor that Execute(), an IVisitor that Visit(), an IParent that exposes Children { get; }. Often, such minimalist interface should be generic. For example the interface ICloneable available since the .NET Framework v1.1 is nowadays considered as a code smell: when using it the client needs to downcast the cloned Object reference returned to do anything useful with the cloned instance.

public interface ICloneable { 
   object Clone(); 
}

public interface ICloneable {

object Clone();

}

ICloneable has another major drawback: it doesn’t inform the client if the clone operation is deep or shallow. This problem is even more serious than the Object reference downcasting one: it is a real design problem. As we can see a minimalist interface is not necessarily a good abstraction. In this example, the lack of information means ambiguity for the client. This would have been better design:

public interface IDeepCloneable<T> { 
   T DeepClone(); 
}
public interface IShallowCloneable<T> { 
   T ShallowClone();
}

public interface IDeepCloneable<T> {

T DeepClone();

}

public interface IShallowCloneable<T> {

T ShallowClone();

}

A fat interface is not necessarily a design flaw

A rule like Avoid too large interfaces can certainly pinpoint most of the ISP violations. A threshold of 10 methods is proposed by default to define a too large interface.

However, as always with code metrics and static analysis, such rule can also spit some false positives. For example this fat interface is valid:

In such case the SuppressMessageAttribute can be used with a proper justification. Such justification embeds in the code itself the design decisions. It makes the source code more understandable and more maintainable:

[SuppressMessage("NDepend", "ND1200:AvoidInterfacesTooBig", Justification="This interface is fat because it needs to support all primitive types"]
public interface IConvertible {
   ...

[SuppressMessage("NDepend", "ND1200:AvoidInterfacesTooBig", Justification="This interface is fat because it needs to support all primitive types"]

public interface IConvertible {

...

ISP and the Liskov Substitution Principle (LSP)

ISP and LSP are like 2 faces of the same coin:

ISP is the client perspective: If an interface is too fat probably the client sees some behaviors it doesn’t care for.
LSP is the implementer perspective: If an interface is too fat probably a class that implements it won’t implement all its behaviors. Some behavior will end up throwing something like a NotSupportedException.

Remember the ICollection<T> interface already discussed in the LSP article. This interface forces all its implementers to implement an Add() method. From the Array class perspective, implementing ICollection<T> is a violation of the LSP because array doesn’t support element adding:

The same way many clients will only need a read-only view of consumed collections. ICollection<T> also violates the ISP: it forces those clients to be coupled with Add() / Insert() / Remove() methods they don’t need. The introduction of IReadOnlyCollection<T> solved both ISP and LSP violations.

This example also shows that ISP doesn’t necessarily mean that a class should implement several lightweight interfaces. It is fine to nest interfaces like russian-nesting-dolls. ICollection<T> is a bit fat, it does a lot, read, add, insert, remove, count… But this interface is well-adapted both for classes that are read/write collections and for clients that work on read/write collection. It makes more sense to nest both read/write behaviors into ICollection<T> than to decompose both behaviors into IReadOnlyCollection<T> and an hypothetical IWriteOnlyCollection<T> interface.

Btw, maybe you noticed that ICollection<T> actually doesn’t implement IReadOnlyCollection<T>. In an ideal world it should implement it but IReadOnlyCollection<T> was introduced several years after ICollection<T> and backward compatibility must be preserved: for example this class would have been broken if ICollection<T> was implementing IReadOnlyCollection<T>, because of the explicit interface implementation usage on ICollection<T>.Count:

class MyCollection<T> : ICollection<T> {
   int ICollection<T>.Count { get { return 0; } }
   // ...
}

class MyCollection<T> : ICollection<T> {

int ICollection<T>.Count { get { return 0; } }

// ...

}

Conclusion

ISP is about preventing inadvertent coupling between a client and some behaviors he/she won’t need. Being coupled with something unneeded is a problem:

In the best case it is a waste: this forces the client to consume precious brain-cycles to consider something he/she doesn’t need.
In the worst case it is error-prone: the client ends-up misusing the extra behaviors, like attempting to add an element to an array through ICollection<T>.Add().

As for all SOLID principles, ISP is better applied if you practice test-first, or at least, if you write tests and code at the same time. ISP is about the client perspective and writing tests transforms you for a while into a client of your code.

Out of curiosity I wrote this code query that can be re-used to attempt to measure compliance with the ISP.

from @interface in Application.Types.Where(t => t.IsInterface && t.Methods.Any() && t.IsInternal)
let tUsers = @interface.TypesUsingMe.Where(t => !t.IsAbstract && !t.Implement(@interface))
where tUsers.Any()
let nbMethodsUsed = tUsers.Sum(t => @interface.Methods.UsedBy(t).Count())
let maximumUsage = tUsers.Count() * @interface.Methods.Count()
select new { 
   @interface, 
   score = (double) nbMethodsUsed /  (double) maximumUsage,
   tUsers,
   interfaceMethods = @interface.Methods
}

from @interface in Application.Types.Where(t => t.IsInterface && t.Methods.Any() && t.IsInternal)

let tUsers = @interface.TypesUsingMe.Where(t => !t.IsAbstract && !t.Implement(@interface))

where tUsers.Any()

let nbMethodsUsed = tUsers.Sum(t => @interface.Methods.UsedBy(t).Count())

let maximumUsage = tUsers.Count() * @interface.Methods.Count()

select new {

@interface,

score = (double) nbMethodsUsed / (double) maximumUsage,

tUsers,

interfaceMethods = @interface.Methods

}

This query estimates the ratio of usage of the methods of an interface over the maximum usage (maximum usage being when all types consuming an interface call all methods of the interface). Some work would be needed to transform this experimental query into a formal rule. For example the query needs to be smart about methods overloaded that can arguably be considered as a single method.

Nevertheless here are the raw results for non-public interfaces of the .NET framework implementation. Only non-public interfaces are considered because we need to also analyze some real clients of the interface:

927 types	score	tUsers	interfaceMethods	Full Name
IExceptionData	0.33	3 types	1 method	Microsoft.Build.Tasks.Xsd.IExceptionData
IDtcNetworkAccessConfig	0.077	2 types	13 methods	Microsoft.Tools.ServiceModel.WsatConfig .IDtcNetworkAccessConfig
INetFirewallOpenPort	0.6	1 type	15 methods	Microsoft.Tools.ServiceModel.WsatConfig .INetFirewallOpenPort
INetFirewallOpenPortsCollection	0.6	1 type	5 methods	Microsoft.Tools.ServiceModel.WsatConfig .INetFirewallOpenPortsCollection
INetFirewallProfile	0.071	1 type	14 methods	Microsoft.Tools.ServiceModel.WsatConfig .INetFirewallProfile
INetFirewallPolicy	0.5	1 type	2 methods	Microsoft.Tools.ServiceModel.WsatConfig .INetFirewallPolicy
INetFirewallMgr	0.2	1 type	5 methods	Microsoft.Tools.ServiceModel.WsatConfig .INetFirewallMgr
IDtdInfo	0.056	23 types	7 methods	System.Xml.IDtdInfo
IDtdAttributeListInfo	0.33	3 types	6 methods	System.Xml.IDtdAttributeListInfo
IDtdAttributeInfo	0.39	4 types	7 methods	System.Xml.IDtdAttributeInfo
IDtdDefaultAttributeInfo	0.11	9 types	4 methods	System.Xml.IDtdDefaultAttributeInfo
IDtdEntityInfo	0.19	6 types	12 methods	System.Xml.IDtdEntityInfo
IDtdParser	0.58	3 types	4 methods	System.Xml.IDtdParser
IDtdParserAdapter	0.21	5 types	32 methods	System.Xml.IDtdParserAdapter
IDtdParserAdapterWithValidation	0.75	2 types	2 methods	System.Xml .IDtdParserAdapterWithValidation
IDtdParserAdapterV1	1	1 type	3 methods	System.Xml.IDtdParserAdapterV1
IValidationEventHandling	0.3	10 types	2 methods	System.Xml.IValidationEventHandling
IRemovableWriter	0.5	1 type	2 methods	System.Xml.IRemovableWriter
INameScope	1	2 types	2 methods	System.Xml.Serialization.INameScope
IXamlBuildProviderExtension	0.5	2 types	2 methods	System.Xaml.Hosting .IXamlBuildProviderExtension
IXamlBuildProviderExtensionFactory	1	1 type	1 method	System.Xaml.Hosting .IXamlBuildProviderExtensionFactory
IAddLineInfo	0.5	2 types	1 method	MS.Internal.Xaml.Runtime.IAddLineInfo
ICheckIfInitialized	0.5	2 types	1 method	MS.Internal.Xaml.Context .ICheckIfInitialized
IServiceDescriptionBuilder	1	1 type	1 method	System.ServiceModel.Description .IServiceDescriptionBuilder
IExternalDataExchange	0.33	3 types	1 method	System.ServiceModel.Activities .IExternalDataExchange
IWDEProgramNode	0	1 type	1 method	System.Workflow.Runtime.DebugEngine .IWDEProgramNode
IWDEProgramPublisher	1	1 type	2 methods	System.Workflow.Runtime.DebugEngine .IWDEProgramPublisher
ISupportWorkflowChanges	1	1 type	3 methods	System.Workflow.ComponentModel .ISupportWorkflowChanges
ISupportAlternateFlow	1	11 types	1 method	System.Workflow.ComponentModel .ISupportAlternateFlow
IDependencyObjectAccessor	0.3	10 types	4 methods	System.Workflow.ComponentModel .IDependencyObjectAccessor
IWorkflowCoreRuntime	0.1	20 types	31 methods	System.Workflow.ComponentModel .IWorkflowCoreRuntime
ITimerService	0.5	2 types	2 methods	System.Workflow.ComponentModel .ITimerService
IWorkflowDesignerMessageSink	0.23	4 types	32 methods	System.Workflow.ComponentModel.Design .IWorkflowDesignerMessageSink
IPropertyValueProvider	1	2 types	1 method	System.Workflow.ComponentModel.Design .IPropertyValueProvider
IOleServiceProvider	0.5	2 types	1 method	System.Workflow.ComponentModel.Compiler .IOleServiceProvider
IWorkflowBuildHostProperties	0.5	1 type	2 methods	System.Workflow.ComponentModel.Compiler .IWorkflowBuildHostProperties
IWorkflowCompilerError	0	1 type	6 methods	System.Workflow.ComponentModel.Compiler .IWorkflowCompilerError
IWorkflowCompilerErrorLogger	1	1 type	2 methods	System.Workflow.ComponentModel.Compiler .IWorkflowCompilerErrorLogger
ISymUnmanagedReader	0.12	1 type	17 methods	System.Workflow.ComponentModel.Compiler .ISymUnmanagedReader
ISymUnmanagedMethod	0.2	1 type	10 methods	System.Workflow.ComponentModel.Compiler .ISymUnmanagedMethod
ISymUnmanagedDocument	0.1	1 type	10 methods	System.Workflow.ComponentModel.Compiler .ISymUnmanagedDocument
IMetaDataDispenser	0.33	1 type	3 methods	System.Workflow.ComponentModel.Compiler .IMetaDataDispenser
ITypeAuthorizer	0.33	3 types	1 method	System.Workflow.ComponentModel .Serialization.ITypeAuthorizer
IDirectoryOperation	0.5	2 types	1 method	System.Workflow.Activities .IDirectoryOperation
ICorrelationProvider	0.33	3 types	2 methods	System.Workflow.Activities .ICorrelationProvider
IMethodResponseMessage	0.25	2 types	4 methods	System.Workflow.Activities .IMethodResponseMessage
IDeliverMessage	0.33	3 types	2 methods	System.Workflow.Activities .IDeliverMessage
IPropertyValueProvider	1	2 types	1 method	System.Workflow.Activities.Common .IPropertyValueProvider
IAliasResolver	1	1 type	2 methods	System.Resources.IAliasResolver
ISection	0	4 types	4 methods	System.Deployment.Internal.Isolation .ISection
ISectionEntry	0	1 type	2 methods	System.Deployment.Internal.Isolation .ISectionEntry
IEnumSTORE_ASSEMBLY_INSTALLATION_REFEREN CE	0	1 type	4 methods	System.Deployment.Internal.Isolation .IEnumSTORE_ASSEMBLY_INSTALLATION_REFERE NCE
IEnumSTORE_DEPLOYMENT_METADATA	0.17	3 types	4 methods	System.Deployment.Internal.Isolation .IEnumSTORE_DEPLOYMENT_METADATA
IEnumSTORE_DEPLOYMENT_METADATA_PROPERTY	0.17	3 types	4 methods	System.Deployment.Internal.Isolation .IEnumSTORE_DEPLOYMENT_METADATA_PROPERTY
IEnumSTORE_ASSEMBLY	0.17	3 types	4 methods	System.Deployment.Internal.Isolation .IEnumSTORE_ASSEMBLY
IEnumSTORE_ASSEMBLY_FILE	0.17	3 types	4 methods	System.Deployment.Internal.Isolation .IEnumSTORE_ASSEMBLY_FILE
IEnumSTORE_CATEGORY	0.17	3 types	4 methods	System.Deployment.Internal.Isolation .IEnumSTORE_CATEGORY
IEnumSTORE_CATEGORY_SUBCATEGORY	0.25	2 types	4 methods	System.Deployment.Internal.Isolation .IEnumSTORE_CATEGORY_SUBCATEGORY
IEnumSTORE_CATEGORY_INSTANCE	0.17	3 types	4 methods	System.Deployment.Internal.Isolation .IEnumSTORE_CATEGORY_INSTANCE
IReferenceIdentity	0.071	7 types	4 methods	System.Deployment.Internal.Isolation .IReferenceIdentity
IDefinitionIdentity	0.038	13 types	4 methods	System.Deployment.Internal.Isolation .IDefinitionIdentity
IEnumDefinitionIdentity	0.17	3 types	4 methods	System.Deployment.Internal.Isolation .IEnumDefinitionIdentity
IEnumReferenceIdentity	0.25	2 types	4 methods	System.Deployment.Internal.Isolation .IEnumReferenceIdentity
IDefinitionAppId	0.059	17 types	6 methods	System.Deployment.Internal.Isolation .IDefinitionAppId
IReferenceAppId	0.2	5 types	5 methods	System.Deployment.Internal.Isolation .IReferenceAppId
IIdentityAuthority	0	1 type	18 methods	System.Deployment.Internal.Isolation .IIdentityAuthority
IAppIdAuthority	0.062	3 types	16 methods	System.Deployment.Internal.Isolation .IAppIdAuthority
IStore	0.24	4 types	20 methods	System.Deployment.Internal.Isolation .IStore
IManifestParseErrorCallback	0	1 type	1 method	System.Deployment.Internal.Isolation .IManifestParseErrorCallback
IManifestInformation	0.5	2 types	1 method	System.Deployment.Internal.Isolation .IManifestInformation
IActContext	0.28	2 types	18 methods	System.Deployment.Internal.Isolation .IActContext
ICMS	0.011	4 types	22 methods	System.Deployment.Internal.Isolation .Manifest.ICMS
IDescriptionMetadataEntry	0.43	1 type	7 methods	System.Deployment.Internal.Isolation .Manifest.IDescriptionMetadataEntry
IDeploymentMetadataEntry	0.17	1 type	6 methods	System.Deployment.Internal.Isolation .Manifest.IDeploymentMetadataEntry
IMetadataSectionEntry	0.14	1 type	21 methods	System.Deployment.Internal.Isolation .Manifest.IMetadataSectionEntry
FileDialogNative+IModalWindow	0	1 type	1 method	System.Windows.Forms .FileDialogNative+IModalWindow
FileDialogNative+IShellItemArray	0.14	2 types	7 methods	System.Windows.Forms .FileDialogNative+IShellItemArray
FileDialogNative+IFileDialog	0.017	5 types	24 methods	System.Windows.Forms .FileDialogNative+IFileDialog
FileDialogNative+IFileOpenDialog	0.038	2 types	26 methods	System.Windows.Forms .FileDialogNative+IFileOpenDialog
FileDialogNative+IFileSaveDialog	0	2 types	29 methods	System.Windows.Forms .FileDialogNative+IFileSaveDialog
FileDialogNative+IFileDialogEvents	0	1 type	7 methods	System.Windows.Forms .FileDialogNative+IFileDialogEvents
FileDialogNative+IShellItem	0	7 types	5 methods	System.Windows.Forms .FileDialogNative+IShellItem
IKeyboardToolTip	0.23	4 types	13 methods	System.Windows.Forms.IKeyboardToolTip
ISupportOleDropSource	1	1 type	2 methods	System.Windows.Forms .ISupportOleDropSource
ISupportToolStripPanel	0.27	6 types	8 methods	System.Windows.Forms .ISupportToolStripPanel
ListView+ListViewItemCollection+IInnerLi st	0.31	3 types	15 methods	System.Windows.Forms .ListView+ListViewItemCollection+IInnerL ist
NativeMethods+IHTMLDocument	0	1 type	1 method	System.Windows.Forms .NativeMethods+IHTMLDocument
UnsafeNativeMethods+IHTMLDocument	0	6 types	1 method	System.Windows.Forms .UnsafeNativeMethods+IHTMLDocument
UnsafeNativeMethods+IHTMLDocument2	0.057	6 types	109 methods	System.Windows.Forms .UnsafeNativeMethods+IHTMLDocument2
UnsafeNativeMethods+IHTMLDocument3	0.049	3 types	41 methods	System.Windows.Forms .UnsafeNativeMethods+IHTMLDocument3
UnsafeNativeMethods+IHTMLDocument4	0.071	2 types	14 methods	System.Windows.Forms .UnsafeNativeMethods+IHTMLDocument4
UnsafeNativeMethods+IHTMLFramesCollectio n2	0.33	3 types	2 methods	System.Windows.Forms .UnsafeNativeMethods+IHTMLFramesCollecti on2
UnsafeNativeMethods+IHTMLLocation	0.039	4 types	19 methods	System.Windows.Forms .UnsafeNativeMethods+IHTMLLocation
UnsafeNativeMethods+IOmHistory	0.17	3 types	4 methods	System.Windows.Forms .UnsafeNativeMethods+IOmHistory
UnsafeNativeMethods+IOmNavigator	0	1 type	19 methods	System.Windows.Forms .UnsafeNativeMethods+IOmNavigator
UnsafeNativeMethods+IHTMLEventObj	0.14	5 types	25 methods	System.Windows.Forms .UnsafeNativeMethods+IHTMLEventObj
UnsafeNativeMethods+IHTMLEventObj2	0	1 type	56 methods	System.Windows.Forms .UnsafeNativeMethods+IHTMLEventObj2
UnsafeNativeMethods+IHTMLEventObj4	0	1 type	1 method	System.Windows.Forms .UnsafeNativeMethods+IHTMLEventObj4
UnsafeNativeMethods+IHTMLElementCollecti on	0.083	4 types	6 methods	System.Windows.Forms .UnsafeNativeMethods+IHTMLElementCollect ion
UnsafeNativeMethods+IHTMLElement	0.043	7 types	87 methods	System.Windows.Forms .UnsafeNativeMethods+IHTMLElement
UnsafeNativeMethods+IHTMLElement2	0.065	3 types	98 methods	System.Windows.Forms .UnsafeNativeMethods+IHTMLElement2
UnsafeNativeMethods+IHTMLElement3	0.035	2 types	43 methods	System.Windows.Forms .UnsafeNativeMethods+IHTMLElement3
UnsafeNativeMethods+IHTMLStyle	0.0056	2 types	178 methods	System.Windows.Forms .UnsafeNativeMethods+IHTMLStyle
UnsafeNativeMethods+ICorRuntimeHost	0.026	2 types	19 methods	System.Windows.Forms .UnsafeNativeMethods+ICorRuntimeHost
UnsafeNativeMethods+IServiceProvider	0	1 type	1 method	System.Windows.Forms .UnsafeNativeMethods+IServiceProvider
UnsafeNativeMethods+IAccessibleEx	0	1 type	4 methods	System.Windows.Forms .UnsafeNativeMethods+IAccessibleEx
PropertyGridView+IMouseHookClient	0.5	2 types	1 method	System.Windows.Forms .PropertyGridInternal .PropertyGridView+IMouseHookClient
IArrangedElement	0.12	32 types	9 methods	System.Windows.Forms.Layout .IArrangedElement
IDataPointCustomPropertiesProvider	1	1 type	1 method	System.Windows.Forms.DataVisualization .Charting .IDataPointCustomPropertiesProvider
IChartElement	0.25	4 types	4 methods	System.Windows.Forms.DataVisualization .Charting.IChartElement
INameController	0.57	1 type	7 methods	System.Windows.Forms.DataVisualization .Charting.INameController
IChartRenderingEngine	0.93	1 type	45 methods	System.Windows.Forms.DataVisualization .Charting.IChartRenderingEngine
IDesignerMessageBoxDialog	0.5	2 types	1 method	System.Windows.Forms.DataVisualization .Charting.IDesignerMessageBoxDialog
IFormula	0.25	2 types	2 methods	System.Windows.Forms.DataVisualization .Charting.Formulas.IFormula
IChartType	0.11	13 types	22 methods	System.Windows.Forms.DataVisualization .Charting.ChartTypes.IChartType
ICircularChartType	0.17	5 types	6 methods	System.Windows.Forms.DataVisualization .Charting.ChartTypes.ICircularChartType
IBorderType	0.3	4 types	5 methods	System.Windows.Forms.DataVisualization .Charting.Borders3D.IBorderType
INotifyConnection2	0.5	2 types	2 methods	System.Web.Services.Interop .INotifyConnection2
INotifySink2	0.5	2 types	4 methods	System.Web.Services.Interop.INotifySink2
INotifySource2	0	1 type	1 method	System.Web.Services.Interop .INotifySource2
IDeviceSpecificChoiceDesigner	0.5	4 types	2 methods	System.Web.UI.Design.MobileControls .IDeviceSpecificChoiceDesigner
IDeviceSpecificDesigner	0.15	11 types	10 methods	System.Web.UI.Design.MobileControls .IDeviceSpecificDesigner
IListDesigner	0.05	2 types	10 methods	System.Web.UI.Design.MobileControls .IListDesigner
IRefreshableDeviceSpecificEditor	0.5	2 types	7 methods	System.Web.UI.Design.MobileControls .IRefreshableDeviceSpecificEditor
NativeMethods+IStream	0	1 type	11 methods	System.Web.UI.Design.MobileControls .NativeMethods+IStream
NativeMethods+IHTMLElement	0.0077	3 types	87 methods	System.Web.UI.Design.MobileControls .NativeMethods+IHTMLElement
NativeMethods+IHTMLDocument2	0.0055	5 types	109 methods	System.Web.UI.Design.MobileControls .NativeMethods+IHTMLDocument2
NativeMethods+IHTMLDocument3	0.012	2 types	41 methods	System.Web.UI.Design.MobileControls .NativeMethods+IHTMLDocument3
NativeMethods+IHTMLStyleSheet	0	1 type	21 methods	System.Web.UI.Design.MobileControls .NativeMethods+IHTMLStyleSheet
NativeMethods+IHTMLStyle	0	1 type	178 methods	System.Web.UI.Design.MobileControls .NativeMethods+IHTMLStyle
NativeMethods+IHTMLElementCollection	0	1 type	6 methods	System.Web.UI.Design.MobileControls .NativeMethods+IHTMLElementCollection
NativeMethods+IHTMLDOMNode	0	1 type	20 methods	System.Web.UI.Design.MobileControls .NativeMethods+IHTMLDOMNode
NativeMethods+IOleContainer	0	2 types	3 methods	System.Web.UI.Design.MobileControls .NativeMethods+IOleContainer
NativeMethods+IOleClientSite	0	1 type	6 methods	System.Web.UI.Design.MobileControls .NativeMethods+IOleClientSite
NativeMethods+IOleDocumentSite	0	1 type	1 method	System.Web.UI.Design.MobileControls .NativeMethods+IOleDocumentSite
NativeMethods+IOleDocumentView	0.15	2 types	13 methods	System.Web.UI.Design.MobileControls .NativeMethods+IOleDocumentView
NativeMethods+IOleInPlaceSite	0	1 type	12 methods	System.Web.UI.Design.MobileControls .NativeMethods+IOleInPlaceSite
NativeMethods+IOleInPlaceFrame	0	1 type	12 methods	System.Web.UI.Design.MobileControls .NativeMethods+IOleInPlaceFrame
NativeMethods+IOleInPlaceUIWindow	0	2 types	6 methods	System.Web.UI.Design.MobileControls .NativeMethods+IOleInPlaceUIWindow
NativeMethods+IDocHostUIHandler	0	1 type	15 methods	System.Web.UI.Design.MobileControls .NativeMethods+IDocHostUIHandler
NativeMethods+IOleInPlaceActiveObject	0	2 types	7 methods	System.Web.UI.Design.MobileControls .NativeMethods+IOleInPlaceActiveObject
NativeMethods+IOleObject	0.048	2 types	21 methods	System.Web.UI.Design.MobileControls .NativeMethods+IOleObject
NativeMethods+IOleCommandTarget	0	2 types	2 methods	System.Web.UI.Design.MobileControls .NativeMethods+IOleCommandTarget
NativeMethods+IOleDropTarget	0	2 types	4 methods	System.Web.UI.Design.MobileControls .NativeMethods+IOleDropTarget
NativeMethods+IOleDataObject	0	2 types	9 methods	System.Web.UI.Design.MobileControls .NativeMethods+IOleDataObject
NativeMethods+IEnumOLEVERB	0	1 type	4 methods	System.Web.UI.Design.MobileControls .NativeMethods+IEnumOLEVERB
NativeMethods+IAdviseSink	0	1 type	5 methods	System.Web.UI.Design.MobileControls .NativeMethods+IAdviseSink
NativeMethods+IHTMLBodyElement	0.014	2 types	35 methods	System.Web.UI.Design.MobileControls .NativeMethods+IHTMLBodyElement
NativeMethods+IPersistStreamInit	0.083	2 types	6 methods	System.Web.UI.Design.MobileControls .NativeMethods+IPersistStreamInit
NativeMethods+IHTMLElement2	0.0094	3 types	106 methods	System.Web.UI.Design.MobileControls .NativeMethods+IHTMLElement2
NativeMethods+IHTMLRectCollection	0.33	2 types	3 methods	System.Web.UI.Design.MobileControls .NativeMethods+IHTMLRectCollection
NativeMethods+IHTMLCurrentStyle	0	1 type	67 methods	System.Web.UI.Design.MobileControls .NativeMethods+IHTMLCurrentStyle
NativeMethods+IHTMLRect	0.12	2 types	8 methods	System.Web.UI.Design.MobileControls .NativeMethods+IHTMLRect
IListControl	1	1 type	2 methods	System.Web.UI.MobileControls .IListControl
IScriptResourceHandler	1	1 type	3 methods	System.Web.Handlers .IScriptResourceHandler
IContractGeneratorReferenceTypeLoader	0.5	2 types	3 methods	System.Web.Compilation.WCFModel .IContractGeneratorReferenceTypeLoader
IContractGeneratorReferenceTypeLoader2	1	1 type	1 method	System.Web.Compilation.WCFModel .IContractGeneratorReferenceTypeLoader2
IClientScriptManager	0.14	5 types	7 methods	System.Web.UI.IClientScriptManager
IClientUrlResolver	0.4	5 types	2 methods	System.Web.UI.IClientUrlResolver
ICompilationSection	1	1 type	1 method	System.Web.UI.ICompilationSection
IControl	0.25	2 types	2 methods	System.Web.UI.IControl
ICustomErrorsSection	0.5	2 types	2 methods	System.Web.UI.ICustomErrorsSection
IDeploymentSection	1	1 type	1 method	System.Web.UI.IDeploymentSection
IHtmlForm	0.33	3 types	4 methods	System.Web.UI.IHtmlForm
IPage	0.12	8 types	31 methods	System.Web.UI.IPage
IScriptManagerInternal	0.17	4 types	12 methods	System.Web.UI.IScriptManagerInternal
IDynamicQueryable	0.14	2 types	7 methods	System.Web.UI.WebControls .IDynamicQueryable
ILinqToSql	0.67	1 type	6 methods	System.Web.UI.WebControls.ILinqToSql
ILinqDataSourceChooseContextType	0.44	2 types	8 methods	System.Web.UI.Design.WebControls .ILinqDataSourceChooseContextType
ILinqDataSourceChooseContextTypePanel	0.5	2 types	4 methods	System.Web.UI.Design.WebControls .ILinqDataSourceChooseContextTypePanel
ILinqDataSourceConfiguration	0.5	2 types	8 methods	System.Web.UI.Design.WebControls .ILinqDataSourceConfiguration
ILinqDataSourceConfigurationPanel	0.5	2 types	8 methods	System.Web.UI.Design.WebControls .ILinqDataSourceConfigurationPanel
ILinqDataSourceConfigureAdvanced	0.5	2 types	1 method	System.Web.UI.Design.WebControls .ILinqDataSourceConfigureAdvanced
ILinqDataSourceConfigureAdvancedForm	0.33	3 types	4 methods	System.Web.UI.Design.WebControls .ILinqDataSourceConfigureAdvancedForm
ILinqDataSourceConfigureGroupBy	0.42	2 types	6 methods	System.Web.UI.Design.WebControls .ILinqDataSourceConfigureGroupBy
ILinqDataSourceConfigureGroupByPanel	0.33	3 types	7 methods	System.Web.UI.Design.WebControls .ILinqDataSourceConfigureGroupByPanel
ILinqDataSourceConfigureOrderBy	0.33	2 types	3 methods	System.Web.UI.Design.WebControls .ILinqDataSourceConfigureOrderBy
ILinqDataSourceConfigureOrderByForm	0.33	3 types	6 methods	System.Web.UI.Design.WebControls .ILinqDataSourceConfigureOrderByForm
ILinqDataSourceConfigureSelect	0.42	2 types	6 methods	System.Web.UI.Design.WebControls .ILinqDataSourceConfigureSelect
ILinqDataSourceConfigureSelectPanel	0.33	3 types	22 methods	System.Web.UI.Design.WebControls .ILinqDataSourceConfigureSelectPanel
ILinqDataSourceConfigureWhere	0.25	4 types	16 methods	System.Web.UI.Design.WebControls .ILinqDataSourceConfigureWhere
ILinqDataSourceConfigureWhereForm	0.28	4 types	15 methods	System.Web.UI.Design.WebControls .ILinqDataSourceConfigureWhereForm
ILinqDataSourceContextTypeItem	0.22	9 types	3 methods	System.Web.UI.Design.WebControls .ILinqDataSourceContextTypeItem
ILinqDataSourceDesignerHelper	0.086	13 types	67 methods	System.Web.UI.Design.WebControls .ILinqDataSourceDesignerHelper
ILinqDataSourceProjection	0.25	5 types	8 methods	System.Web.UI.Design.WebControls .ILinqDataSourceProjection
ILinqDataSourcePropertyItem	0.099	22 types	11 methods	System.Web.UI.Design.WebControls .ILinqDataSourcePropertyItem
ILinqDataSourceStatementEditorForm	0.38	2 types	4 methods	System.Web.UI.Design.WebControls .ILinqDataSourceStatementEditorForm
ILinqDataSourceWizardForm	0.33	6 types	2 methods	System.Web.UI.Design.WebControls .ILinqDataSourceWizardForm
ILinqDataSourceWrapper	0.5	2 types	44 methods	System.Web.UI.Design.WebControls .ILinqDataSourceWrapper
IMetaChildrenColumn	0.17	1 type	6 methods	System.Web.DynamicData .IMetaChildrenColumn
IMetaColumn	0.073	6 types	39 methods	System.Web.DynamicData.IMetaColumn
IMetaForeignKeyColumn	0.17	2 types	9 methods	System.Web.DynamicData .IMetaForeignKeyColumn
IMetaModel	0.019	3 types	18 methods	System.Web.DynamicData.IMetaModel
IMetaTable	0.035	10 types	43 methods	System.Web.DynamicData.IMetaTable
MetaColumn+IMetaColumnMetadata	0.37	3 types	20 methods	System.Web.DynamicData .MetaColumn+IMetaColumnMetadata
IClrStrongNameUsingIntPtr	0.24	1 type	25 methods	Microsoft.Runtime.Hosting .IClrStrongNameUsingIntPtr
IClrStrongName	0.36	1 type	25 methods	Microsoft.Runtime.Hosting.IClrStrongName
IRequestCompletedNotifier	0.5	2 types	1 method	System.Web.IRequestCompletedNotifier
IBufferAllocator	0.083	3 types	4 methods	System.Web.IBufferAllocator
IBufferAllocator<T>	0.33	4 types	3 methods	System.Web.IBufferAllocator<T>
IAllocatorProvider	0.25	5 types	4 methods	System.Web.IAllocatorProvider
HttpApplication+IExecutionStep	0.2	5 types	3 methods	System.Web .HttpApplication+IExecutionStep
IHttpResponseElement	0.83	2 types	3 methods	System.Web.IHttpResponseElement
IHttpHandlerFactory2	1	1 type	1 method	System.Web.IHttpHandlerFactory2
IPartitionInfo	0.25	4 types	1 method	System.Web.IPartitionInfo
IAsyncAbortableWebSocket	0.5	2 types	1 method	System.Web.WebSockets .IAsyncAbortableWebSocket
IWebSocketPipe	0.5	2 types	4 methods	System.Web.WebSockets.IWebSocketPipe
IUnmanagedWebSocketContext	0.5	2 types	5 methods	System.Web.WebSockets .IUnmanagedWebSocketContext
IPerfCounters	0.12	4 types	4 methods	System.Web.Util.IPerfCounters
ISyncContextLock	0.33	3 types	1 method	System.Web.Util.ISyncContextLock
ISyncContext	0.2	5 types	2 methods	System.Web.Util.ISyncContext
ITypedWebObjectFactory	1	4 types	1 method	System.Web.Util.ITypedWebObjectFactory
ICustomRuntimeRegistrationToken	0	2 types	1 method	System.Web.Hosting .ICustomRuntimeRegistrationToken
IProcessSuspendListener	1	1 type	1 method	System.Web.Hosting .IProcessSuspendListener
IProcessResumeCallback	0.5	2 types	1 method	System.Web.Hosting .IProcessResumeCallback
ICustomRuntime	0	3 types	3 methods	System.Web.Hosting.ICustomRuntime
IStateFormatter2	0.62	8 types	2 methods	System.Web.UI.IStateFormatter2
IPageAsyncTask	0.5	2 types	1 method	System.Web.UI.IPageAsyncTask
IAssemblyDependencyParser	1	1 type	1 method	System.Web.UI.IAssemblyDependencyParser
IScriptResourceMapping	0.5	3 types	2 methods	System.Web.UI.IScriptResourceMapping
IScriptResourceDefinition	0.33	3 types	8 methods	System.Web.UI.IScriptResourceDefinition
IScriptManager	0.15	11 types	17 methods	System.Web.UI.IScriptManager
ITagNameToTypeMapper	1	1 type	1 method	System.Web.UI.ITagNameToTypeMapper
IRenderOuterTableControl	1	1 type	3 methods	System.Web.UI.IRenderOuterTableControl
IWizardSideBarListControl	0.1	5 types	12 methods	System.Web.UI.WebControls .IWizardSideBarListControl
IWebPartMenuUser	1	1 type	16 methods	System.Web.UI.WebControls.WebParts .IWebPartMenuUser
NativeComInterfaces+IAdsPathname	0.12	3 types	11 methods	System.Web.Security .NativeComInterfaces+IAdsPathname
NativeComInterfaces+IAdsLargeInteger	0.5	3 types	4 methods	System.Web.Security .NativeComInterfaces+IAdsLargeInteger
IDataProtectorFactory	0.5	2 types	1 method	System.Web.Security.Cryptography .IDataProtectorFactory
ICryptoServiceProvider	1	1 type	1 method	System.Web.Security.Cryptography .ICryptoServiceProvider
IMasterKeyProvider	0.5	2 types	2 methods	System.Web.Security.Cryptography .IMasterKeyProvider
ICryptoAlgorithmFactory	0.5	2 types	2 methods	System.Web.Security.Cryptography .ICryptoAlgorithmFactory
ICryptoService	0.83	6 types	2 methods	System.Web.Security.Cryptography .ICryptoService
IAssemblyCache	0.2	2 types	5 methods	System.Web.Configuration.IAssemblyCache
IConfigMapPath2	0.67	2 types	3 methods	System.Web.Configuration.IConfigMapPath2
IServerConfig	0.2	6 types	5 methods	System.Web.Configuration.IServerConfig
IServerConfig2	1	1 type	1 method	System.Web.Configuration.IServerConfig2
IDataPointCustomPropertiesProvider	1	1 type	1 method	System.Web.UI.DataVisualization.Charting .IDataPointCustomPropertiesProvider
IChartElement	0.25	3 types	4 methods	System.Web.UI.DataVisualization.Charting .IChartElement
INameController	0.57	1 type	7 methods	System.Web.UI.DataVisualization.Charting .INameController
IChartRenderingEngine	0.93	1 type	45 methods	System.Web.UI.DataVisualization.Charting .IChartRenderingEngine
IDesignerMessageBoxDialog	0.5	2 types	1 method	System.Web.UI.DataVisualization.Charting .IDesignerMessageBoxDialog
IFormula	0.25	2 types	2 methods	System.Web.UI.DataVisualization.Charting .Formulas.IFormula
IChartType	0.11	14 types	22 methods	System.Web.UI.DataVisualization.Charting .ChartTypes.IChartType
ICircularChartType	0.17	5 types	6 methods	System.Web.UI.DataVisualization.Charting .ChartTypes.ICircularChartType
IBorderType	0.3	4 types	5 methods	System.Web.UI.DataVisualization.Charting .Borders3D.IBorderType
IMembershipAdapter	0.27	3 types	5 methods	System.Web.Security.IMembershipAdapter
ICustomLoaderHelperFunctions	0.5	2 types	4 methods	System.Web.Hosting .ICustomLoaderHelperFunctions
IPromotedEnlistment	0.089	14 types	12 methods	System.Transactions.IPromotedEnlistment
IEnlistmentNotificationInternal	0.28	8 types	4 methods	System.Transactions .IEnlistmentNotificationInternal
ISinglePhaseNotificationInternal	0.25	4 types	1 method	System.Transactions .ISinglePhaseNotificationInternal
IVoterBallotShim	0.5	2 types	1 method	System.Transactions.Oletx .IVoterBallotShim
IPhase0EnlistmentShim	0.38	4 types	2 methods	System.Transactions.Oletx .IPhase0EnlistmentShim
IEnlistmentShim	0.5	2 types	3 methods	System.Transactions.Oletx .IEnlistmentShim
ITransactionShim	0.25	4 types	8 methods	System.Transactions.Oletx .ITransactionShim
IResourceManagerShim	0.44	3 types	3 methods	System.Transactions.Oletx .IResourceManagerShim
IDtcProxyShimFactory	0.2	5 types	8 methods	System.Transactions.Oletx .IDtcProxyShimFactory
ITransactionNativeInternal	0.33	1 type	3 methods	System.Transactions.Oletx .ITransactionNativeInternal
IWebFaultException	1	1 type	4 methods	System.ServiceModel.Web .IWebFaultException
IDuplexRouterCallback	0.33	3 types	2 methods	System.ServiceModel.Routing .IDuplexRouterCallback
IRoutingClient	0.23	5 types	7 methods	System.ServiceModel.Routing .IRoutingClient
IAsyncEventArgs	0.7	5 types	2 methods	System.Runtime.IAsyncEventArgs
IClassFactory	0.25	2 types	2 methods	IClassFactory
IOperationContractAttributeProvider	1	1 type	1 method	System.ServiceModel .IOperationContractAttributeProvider
ICatalog2	0.018	1 type	57 methods	System.ServiceModel.ComIntegration .ICatalog2
ICatalogObject	0.24	3 types	7 methods	System.ServiceModel.ComIntegration .ICatalogObject
ICatalogCollection	0.17	3 types	16 methods	System.ServiceModel.ComIntegration .ICatalogCollection
ICreateServiceChannel	1	1 type	1 method	System.ServiceModel.ComIntegration .ICreateServiceChannel
IMoniker	0	1 type	20 methods	System.ServiceModel.ComIntegration .IMoniker
IParseDisplayName	0	1 type	1 method	System.ServiceModel.ComIntegration .IParseDisplayName
IProvideChannelBuilderSettings	0.12	4 types	4 methods	System.ServiceModel.ComIntegration .IProvideChannelBuilderSettings
IProxyCreator	0.5	2 types	4 methods	System.ServiceModel.ComIntegration .IProxyCreator
IProxyManager	0	4 types	6 methods	System.ServiceModel.ComIntegration .IProxyManager
IProxyProvider	0.5	2 types	2 methods	System.ServiceModel.ComIntegration .IProxyProvider
IPseudoDispatch	0	1 type	2 methods	System.ServiceModel.ComIntegration .IPseudoDispatch
ITransactionProxy	0	1 type	7 methods	System.ServiceModel.ComIntegration .ITransactionProxy
ITransactionVoterBallotAsync2	0	1 type	1 method	System.ServiceModel.ComIntegration .ITransactionVoterBallotAsync2
ITransactionVoterNotifyAsync2	0.4	2 types	5 methods	System.ServiceModel.ComIntegration .ITransactionVoterNotifyAsync2
ITypeCacheManager	0.33	3 types	4 methods	System.ServiceModel.ComIntegration .ITypeCacheManager
IPersistStream	0.2	3 types	5 methods	System.ServiceModel.ComIntegration .IPersistStream
IServiceThreadPoolConfig	1	1 type	2 methods	System.ServiceModel.ComIntegration .IServiceThreadPoolConfig
IServicePartitionConfig	1	1 type	2 methods	System.ServiceModel.ComIntegration .IServicePartitionConfig
IServiceSysTxnConfig	0.14	1 type	7 methods	System.ServiceModel.ComIntegration .IServiceSysTxnConfig
IServiceSxsConfig	1	1 type	3 methods	System.ServiceModel.ComIntegration .IServiceSxsConfig
IServiceTransactionConfig	0.17	1 type	6 methods	System.ServiceModel.ComIntegration .IServiceTransactionConfig
IServiceCall	0	1 type	1 method	System.ServiceModel.ComIntegration .IServiceCall
IServiceActivity	0.25	2 types	4 methods	System.ServiceModel.ComIntegration .IServiceActivity
IComThreadingInfo	0.17	3 types	4 methods	System.ServiceModel.ComIntegration .IComThreadingInfo
IObjectContextInfo	0.3	2 types	5 methods	System.ServiceModel.ComIntegration .IObjectContextInfo
IContractResolver	0.2	5 types	1 method	System.ServiceModel.Description .IContractResolver
ServiceMetadataExtension+IHttpGetMetadat a	0	2 types	1 method	System.ServiceModel.Description .ServiceMetadataExtension+IHttpGetMetada ta
IWrappedBodyTypeGenerator	0.25	4 types	3 methods	System.ServiceModel.Description .IWrappedBodyTypeGenerator
WbemNative+IWbemProviderInit	0	1 type	1 method	System.ServiceModel.Administration .WbemNative+IWbemProviderInit
WbemNative+IWbemDecoupledRegistrar	0.5	2 types	2 methods	System.ServiceModel.Administration .WbemNative+IWbemDecoupledRegistrar
WbemNative+IWbemServices	0.022	4 types	23 methods	System.ServiceModel.Administration .WbemNative+IWbemServices
WbemNative+IWbemClassObject	0.056	6 types	24 methods	System.ServiceModel.Administration .WbemNative+IWbemClassObject
WbemNative+IWbemContext	0	5 types	9 methods	System.ServiceModel.Administration .WbemNative+IWbemContext
WbemNative+IWbemProviderInitSink	0.5	2 types	1 method	System.ServiceModel.Administration .WbemNative+IWbemProviderInitSink
WbemNative+IWbemObjectSink	0.33	6 types	2 methods	System.ServiceModel.Administration .WbemNative+IWbemObjectSink
WbemNative+IEnumWbemClassObject	0	2 types	5 methods	System.ServiceModel.Administration .WbemNative+IEnumWbemClassObject
WbemNative+IWbemQualifierSet	0	1 type	7 methods	System.ServiceModel.Administration .WbemNative+IWbemQualifierSet
IWmiProvider	0.5	2 types	5 methods	System.ServiceModel.Administration .IWmiProvider
IWmiInstances	0.75	8 types	2 methods	System.ServiceModel.Administration .IWmiInstances
IWmiInstance	0.44	22 types	3 methods	System.ServiceModel.Administration .IWmiInstance
IWmiMethodContext	0.27	3 types	5 methods	System.ServiceModel.Administration .IWmiMethodContext
IWmiInstanceProvider	1	3 types	2 methods	System.ServiceModel.Administration .IWmiInstanceProvider
IFunctionLibrary	1	1 type	1 method	System.ServiceModel.Dispatcher .IFunctionLibrary
INodeCounter	0.5	2 types	6 methods	System.ServiceModel.Dispatcher .INodeCounter
IItemComparer<K,V>	0.5	2 types	1 method	System.ServiceModel.Dispatcher .IItemComparer<K,V>
ConcurrencyBehavior+IWaiter	0.5	2 types	1 method	System.ServiceModel.Dispatcher .ConcurrencyBehavior+IWaiter
IClientFaultFormatter	0.33	6 types	1 method	System.ServiceModel.Dispatcher .IClientFaultFormatter
IDispatchFaultFormatter	0.22	9 types	1 method	System.ServiceModel.Dispatcher .IDispatchFaultFormatter
IDispatchFaultFormatterWrapper	0.5	1 type	2 methods	System.ServiceModel.Dispatcher .IDispatchFaultFormatterWrapper
IChannelBinder	0.076	23 types	20 methods	System.ServiceModel.Dispatcher .IChannelBinder
IListenerBinder	0.3	4 types	5 methods	System.ServiceModel.Dispatcher .IListenerBinder
IManualConcurrencyOperationInvoker	0.56	3 types	3 methods	System.ServiceModel.Dispatcher .IManualConcurrencyOperationInvoker
IInvokeReceivedNotification	0.19	8 types	2 methods	System.ServiceModel.Dispatcher .IInvokeReceivedNotification
IResumeMessageRpc	0.17	8 types	6 methods	System.ServiceModel.Dispatcher .IResumeMessageRpc
IInstanceTransaction	1	1 type	1 method	System.ServiceModel.Dispatcher .IInstanceTransaction
IInstanceContextManager	0.4	1 type	10 methods	System.ServiceModel.Dispatcher .IInstanceContextManager
ISessionThrottleNotification	1	1 type	1 method	System.ServiceModel.Dispatcher .ISessionThrottleNotification
IConfigurationContextProviderInternal	0.33	3 types	2 methods	System.ServiceModel.Configuration .IConfigurationContextProviderInternal
ILockingQueue	1	1 type	2 methods	System.ServiceModel.Channels .ILockingQueue
IChannelDemuxer	1	2 types	7 methods	System.ServiceModel.Channels .IChannelDemuxer
IChannelDemuxFailureHandler	0.16	11 types	4 methods	System.ServiceModel.Channels .IChannelDemuxFailureHandler
IChannelAcceptor<TChannel>	0	12 types	6 methods	System.ServiceModel.Channels .IChannelAcceptor<TChannel>
IRequestReplyCorrelator	0.17	6 types	2 methods	System.ServiceModel.Channels .IRequestReplyCorrelator
ICorrelatorKey	0.5	2 types	2 methods	System.ServiceModel.Channels .ICorrelatorKey
ICommunicationWaiter	0.75	2 types	2 methods	System.ServiceModel.Channels .ICommunicationWaiter
RemoteEndpointMessageProperty+IRemoteEnd pointProvider	0.5	2 types	2 methods	System.ServiceModel.Channels .RemoteEndpointMessageProperty+IRemoteEn dpointProvider
IRequestBase	0.33	1 type	3 methods	System.ServiceModel.Channels .IRequestBase
IRequest	0	3 types	2 methods	System.ServiceModel.Channels.IRequest
IAsyncRequest	0	3 types	2 methods	System.ServiceModel.Channels .IAsyncRequest
IConnectionOrientedListenerSettings	0	5 types	4 methods	System.ServiceModel.Channels .IConnectionOrientedListenerSettings
ITransportFactorySettings	0.2	16 types	5 methods	System.ServiceModel.Channels .ITransportFactorySettings
IConnectionOrientedTransportFactorySetti ngs	0.092	19 types	4 methods	System.ServiceModel.Channels .IConnectionOrientedTransportFactorySett ings
IConnectionOrientedTransportChannelFacto rySettings	0	6 types	2 methods	System.ServiceModel.Channels .IConnectionOrientedTransportChannelFact orySettings
ITcpChannelFactorySettings	0.5	2 types	1 method	System.ServiceModel.Channels .ITcpChannelFactorySettings
IHttpTransportFactorySettings	0.042	12 types	2 methods	System.ServiceModel.Channels .IHttpTransportFactorySettings
IPipeTransportFactorySettings	0.33	3 types	1 method	System.ServiceModel.Channels .IPipeTransportFactorySettings
ITransportManagerRegistration	0	7 types	3 methods	System.ServiceModel.Channels .ITransportManagerRegistration
IChannelBindingProvider	0.5	11 types	2 methods	System.ServiceModel.Channels .IChannelBindingProvider
IStreamUpgradeChannelBindingProvider	0.5	6 types	2 methods	System.ServiceModel.Channels .IStreamUpgradeChannelBindingProvider
IConnection	0.078	62 types	19 methods	System.ServiceModel.Channels.IConnection
IConnectionInitiator	0.095	7 types	3 methods	System.ServiceModel.Channels .IConnectionInitiator
IConnectionListener	0.12	8 types	3 methods	System.ServiceModel.Channels .IConnectionListener
IMessageSource	0.14	7 types	6 methods	System.ServiceModel.Channels .IMessageSource
ISingletonChannelListener	0.14	7 types	2 methods	System.ServiceModel.Channels .ISingletonChannelListener
ISocketListenerSettings	0.5	2 types	3 methods	System.ServiceModel.Channels .ISocketListenerSettings
HttpChannelListener+IHttpAuthenticationC ontext	0.38	2 types	4 methods	System.ServiceModel.Channels .HttpChannelListener+IHttpAuthentication Context
HttpRequestMessageProperty+IHttpHeaderPr ovider	0.25	4 types	1 method	System.ServiceModel.Channels .HttpRequestMessageProperty+IHttpHeaderP rovider
IWebMessageEncoderHelper	1	1 type	1 method	System.ServiceModel.Channels .IWebMessageEncoderHelper
ITransportPolicyImport	1	2 types	1 method	System.ServiceModel.Channels .ITransportPolicyImport
IPoisonHandlingStrategy	0.5	2 types	3 methods	System.ServiceModel.Channels .IPoisonHandlingStrategy
IMsmqMessagePool	0.25	4 types	2 methods	System.ServiceModel.Channels .IMsmqMessagePool
IPostRollbackErrorStrategy	1	2 types	1 method	System.ServiceModel.Channels .IPostRollbackErrorStrategy
MsmqUri+IAddressTranslator	0.29	26 types	3 methods	System.ServiceModel.Channels .MsmqUri+IAddressTranslator
IReliableChannelBinder	0.07	47 types	36 methods	System.ServiceModel.Channels .IReliableChannelBinder
IClientReliableChannelBinder	0.083	16 types	9 methods	System.ServiceModel.Channels .IClientReliableChannelBinder
IServerReliableChannelBinder	0.12	24 types	5 methods	System.ServiceModel.Channels .IServerReliableChannelBinder
IReliableFactorySettings	0.19	10 types	10 methods	System.ServiceModel.Channels .IReliableFactorySettings
DatagramAdapter+DatagramAdapterListenerB ase<TChannel,TSessionChannel,ItemType >+IWaiter	0	1 type	1 method	System.ServiceModel.Channels .DatagramAdapter+DatagramAdapterListener Base<TChannel,TSessionChannel,ItemType >+IWaiter
IMergeEnabledMessageProperty	1	1 type	1 method	System.ServiceModel.Channels .IMergeEnabledMessageProperty
IBufferedMessageData	0.27	10 types	9 methods	System.ServiceModel.Channels .IBufferedMessageData
ICompressedMessageEncoder	0.67	4 types	3 methods	System.ServiceModel.Channels .ICompressedMessageEncoder
ITransportCompressionSupport	0.33	3 types	1 method	System.ServiceModel.Channels .ITransportCompressionSupport
IPeerNeighbor	0.11	18 types	18 methods	System.ServiceModel.Channels .IPeerNeighbor
IPeerFactory	0.28	4 types	8 methods	System.ServiceModel.Channels .IPeerFactory
IFlooderForThrottle	0.5	1 type	2 methods	System.ServiceModel.Channels .IFlooderForThrottle
IPeerMaintainer	1	1 type	17 methods	System.ServiceModel.Channels .IPeerMaintainer
IConnectAlgorithms	1	1 type	4 methods	System.ServiceModel.Channels .IConnectAlgorithms
IPeerNodeMessageHandling	0.071	6 types	7 methods	System.ServiceModel.Channels .IPeerNodeMessageHandling
IPeerConnectorContract	0.5	2 types	4 methods	System.ServiceModel.Channels .IPeerConnectorContract
IPeerFlooderContract<TFloodContract ,TLinkContract>	0.5	2 types	3 methods	System.ServiceModel.Channels .IPeerFlooderContract<TFloodContract ,TLinkContract>
IPeerServiceContract	0.2	1 type	10 methods	System.ServiceModel.Channels .IPeerServiceContract
ITransactionChannel	0.25	1 type	4 methods	System.ServiceModel.Channels .ITransactionChannel
WSTrustDec2005+DriverDec2005+IWsTrustDec 2005SecurityTokenService	0	2 types	1 method	System.ServiceModel.Security .WSTrustDec2005+DriverDec2005+IWsTrustDe c2005SecurityTokenService
WSTrustFeb2005+DriverFeb2005+IWsTrustFeb 2005SecurityTokenService	0	2 types	1 method	System.ServiceModel.Security .WSTrustFeb2005+DriverFeb2005+IWsTrustFe b2005SecurityTokenService
IChannelSecureConversationSessionSetting s	0	1 type	6 methods	System.ServiceModel.Security .IChannelSecureConversationSessionSettin gs
IListenerSecureConversationSessionSettin gs	0	1 type	12 methods	System.ServiceModel.Security .IListenerSecureConversationSessionSetti ngs
ISecurityCommunicationObject	1	1 type	14 methods	System.ServiceModel.Security .ISecurityCommunicationObject
TimeBoundedCache+IExpirableItem	0.5	4 types	1 method	System.ServiceModel.Security .TimeBoundedCache+IExpirableItem
ISecurityContextSecurityTokenCacheProvid er	1	2 types	1 method	System.ServiceModel.Security.Tokens .ISecurityContextSecurityTokenCacheProvi der
IAspNetMessageProperty	0.17	6 types	4 methods	System.ServiceModel.Activation .IAspNetMessageProperty
IConnectionDuplicator	1	1 type	2 methods	System.ServiceModel.Activation .IConnectionDuplicator
IConnectionRegister	0.67	1 type	3 methods	System.ServiceModel.Activation .IConnectionRegister
IConnectionRegisterAsync	0.5	2 types	2 methods	System.ServiceModel.Activation .IConnectionRegisterAsync
ListenerUnsafeNativeMethods+ICorRuntimeH ost	0.045	2 types	11 methods	System.ServiceModel.Activation .ListenerUnsafeNativeMethods+ICorRuntime Host
IAnnouncementInnerClient	0.25	4 types	19 methods	System.ServiceModel.Discovery .IAnnouncementInnerClient
IAnnouncementServiceImplementation	0	6 types	5 methods	System.ServiceModel.Discovery .IAnnouncementServiceImplementation
IDiscoveryInnerClient	0.25	4 types	12 methods	System.ServiceModel.Discovery .IDiscoveryInnerClient
IDiscoveryInnerClientResponse	0.42	8 types	5 methods	System.ServiceModel.Discovery .IDiscoveryInnerClientResponse
IDiscoveryServiceImplementation	0	10 types	6 methods	System.ServiceModel.Discovery .IDiscoveryServiceImplementation
IDiscoveryVersionImplementation	0.14	10 types	11 methods	System.ServiceModel.Discovery .IDiscoveryVersionImplementation
IMulticastSuppressionImplementation	0	6 types	4 methods	System.ServiceModel.Discovery .IMulticastSuppressionImplementation
IAnnouncementContractCD1	0.5	2 types	6 methods	System.ServiceModel.Discovery.VersionCD1 .IAnnouncementContractCD1
IDiscoveryContractAdhocCD1	0.33	3 types	6 methods	System.ServiceModel.Discovery.VersionCD1 .IDiscoveryContractAdhocCD1
IDiscoveryContractManagedCD1	0.5	2 types	6 methods	System.ServiceModel.Discovery.VersionCD1 .IDiscoveryContractManagedCD1
IDiscoveryResponseContractCD1	0.67	2 types	6 methods	System.ServiceModel.Discovery.VersionCD1 .IDiscoveryResponseContractCD1
IAnnouncementContractApril2005	0.5	2 types	6 methods	System.ServiceModel.Discovery .VersionApril2005 .IAnnouncementContractApril2005
IDiscoveryContractApril2005	1	1 type	6 methods	System.ServiceModel.Discovery .VersionApril2005 .IDiscoveryContractApril2005
IDiscoveryResponseContractApril2005	0.67	2 types	6 methods	System.ServiceModel.Discovery .VersionApril2005 .IDiscoveryResponseContractApril2005
IAnnouncementContract11	0.5	2 types	6 methods	System.ServiceModel.Discovery.Version11 .IAnnouncementContract11
IDiscoveryContractAdhoc11	0.33	3 types	6 methods	System.ServiceModel.Discovery.Version11 .IDiscoveryContractAdhoc11
IDiscoveryContractManaged11	0.5	2 types	6 methods	System.ServiceModel.Discovery.Version11 .IDiscoveryContractManaged11
IDiscoveryResponseContract11	0.67	2 types	6 methods	System.ServiceModel.Discovery.Version11 .IDiscoveryResponseContract11
IUdpReceiveHandler	1	1 type	3 methods	System.ServiceModel.Channels .IUdpReceiveHandler
IServiceModelActivationHandler	0.5	2 types	1 method	System.ServiceModel.Activation .IServiceModelActivationHandler
IMSAdminBase	0.097	1 type	31 methods	System.ServiceModel.Activation .IMSAdminBase
ICanonicalizableNode	0.33	3 types	4 methods	System.Security.Cryptography.Xml .ICanonicalizableNode
IStorageFolderHandleAccess	1	1 type	1 method	System.IO.IStorageFolderHandleAccess
IStorageItemHandleAccess	1	1 type	1 method	System.IO.IStorageItemHandleAccess
IDispatcherQueue	0.17	2 types	3 methods	System.Threading.IDispatcherQueue
IBufferByteAccess	1	1 type	1 method	System.Runtime.InteropServices .WindowsRuntime.IBufferByteAccess
IRestrictedErrorInfo	1	1 type	2 methods	System.Runtime.InteropServices .WindowsRuntime.IRestrictedErrorInfo
ISerParser	0.5	2 types	1 method	System.Runtime.Serialization.Formatters .Soap.ISerParser
IDataNode	0.15	10 types	18 methods	System.Runtime.Serialization.IDataNode
IGenericNameProvider	0	2 types	6 methods	System.Runtime.Serialization .IGenericNameProvider
IByteBufferPool	0.23	15 types	2 methods	System.IO.IByteBufferPool
WsdlParser+IDump	1	1 type	1 method	System.Runtime.Remoting.MetadataServices .WsdlParser+IDump
WsdlParser+INamespaces	0	1 type	1 method	System.Runtime.Remoting.MetadataServices .WsdlParser+INamespaces
ICancelable	1	1 type	1 method	System.Runtime.ICancelable
IPersistencePipelineModule	0.16	8 types	11 methods	System.Runtime .IPersistencePipelineModule
IDurableInstancingOptions	1	1 type	1 method	System.Runtime.DurableInstancing .IDurableInstancingOptions
IPersistStream	0	2 types	5 methods	System.Messaging.Interop.IPersistStream
IPersistStreamInit	0.17	1 type	6 methods	System.Messaging.Interop .IPersistStreamInit
IStream	0	2 types	11 methods	System.Messaging.Interop.IStream
ITransaction	0.17	4 types	3 methods	System.Messaging.Interop.ITransaction
IWbemPathKeyList	0.2	1 type	10 methods	WmiNative.IWbemPathKeyList
IWbemPath	0.15	1 type	26 methods	WmiNative.IWbemPath
IWbemDecoupledRegistrar	1	1 type	2 methods	WmiNative.IWbemDecoupledRegistrar
IWbemServices	0.043	1 type	23 methods	WmiNative.IWbemServices
IWbemClassObject	0.065	7 types	24 methods	WmiNative.IWbemClassObject
IWbemContext	0	4 types	9 methods	WmiNative.IWbemContext
IWbemProviderInitSink	0.5	2 types	1 method	WmiNative.IWbemProviderInitSink
IWbemObjectSink	0.33	3 types	2 methods	WmiNative.IWbemObjectSink
IEnumWbemClassObject	0	2 types	5 methods	WmiNative.IEnumWbemClassObject
IWbemQualifierSet	0.14	1 type	7 methods	WmiNative.IWbemQualifierSet
ICIMResultHandler	0.2	3 types	5 methods	System.Management.Instrumentation .ICIMResultHandler
ICIMQuery	0	1 type	1 method	System.Management.Instrumentation .ICIMQuery
ICIMEnumerate	0.5	2 types	1 method	System.Management.Instrumentation .ICIMEnumerate
ICIMGet	0.5	2 types	1 method	System.Management.Instrumentation .ICIMGet
ICIMDelete	0.5	2 types	1 method	System.Management.Instrumentation .ICIMDelete
ICIMUpdate	0.5	2 types	1 method	System.Management.Instrumentation .ICIMUpdate
ICIMExecute	0.5	2 types	1 method	System.Management.Instrumentation .ICIMExecute
ICIMCapabilities	0.83	1 type	6 methods	System.Management.Instrumentation .ICIMCapabilities
IWbemClassObject_DoNotMarshal	0	5 types	24 methods	System.Management .IWbemClassObject_DoNotMarshal
IWbemLocator	0	1 type	1 method	System.Management.IWbemLocator
IWbemContext	0.014	16 types	9 methods	System.Management.IWbemContext
IWbemServices	0.041	19 types	23 methods	System.Management.IWbemServices
IWbemCallResult	0.5	1 type	4 methods	System.Management.IWbemCallResult
IWbemObjectSink	0.11	9 types	2 methods	System.Management.IWbemObjectSink
IEnumWbemClassObject	0.053	15 types	5 methods	System.Management.IEnumWbemClassObject
IWbemObjectTextSrc	0.5	1 type	2 methods	System.Management.IWbemObjectTextSrc
IWbemStatusCodeText	0.5	1 type	2 methods	System.Management.IWbemStatusCodeText
IWbemProviderInitSink	1	1 type	1 method	System.Management.IWbemProviderInitSink
IWbemDecoupledRegistrar	1	1 type	2 methods	System.Management .IWbemDecoupledRegistrar
IWbemPathKeyList	0.2	1 type	10 methods	System.Management.IWbemPathKeyList
IWbemPath	0.46	1 type	26 methods	System.Management.IWbemPath
IMetaDataDispenser	0.33	1 type	3 methods	System.Management.Instrumentation .IMetaDataDispenser
IMetaDataImportInternalOnly	0.12	1 type	8 methods	System.Management.Instrumentation .IMetaDataImportInternalOnly
ILog	1	1 type	7 methods	System.IO.Log.ILog
IFileBasedLogInit	1	1 type	1 method	System.IO.Log.IFileBasedLogInit
ISspiNegotiation	0.1	11 types	8 methods	System.ServiceModel.Security .ISspiNegotiation
ISspiNegotiationInfo	1	1 type	1 method	System.ServiceModel.Security .ISspiNegotiationInfo
IPrefixGenerator	0	2 types	1 method	System.IdentityModel.IPrefixGenerator
ISecurityElement	0.29	7 types	3 methods	System.IdentityModel.ISecurityElement
ISignatureValueSecurityElement	0	5 types	1 method	System.IdentityModel .ISignatureValueSecurityElement
ICanonicalWriterEndRootElementCallback	1	1 type	1 method	System.IdentityModel .ICanonicalWriterEndRootElementCallback
IIdentityInfo	1	1 type	1 method	System.IdentityModel.Policy .IIdentityInfo
IClrStrongNameUsingIntPtr	0.24	1 type	25 methods	Microsoft.Runtime.Hosting .IClrStrongNameUsingIntPtr
IClrStrongName	0.36	1 type	25 methods	Microsoft.Runtime.Hosting.IClrStrongName
IGetContextProperties	0.33	1 type	3 methods	System.EnterpriseServices .IGetContextProperties
IContextProperties	0.2	1 type	5 methods	System.EnterpriseServices .IContextProperties
IObjectConstruct	0	1 type	1 method	System.EnterpriseServices .IObjectConstruct
IObjectConstructString	1	2 types	1 method	System.EnterpriseServices .IObjectConstructString
IObjectContext	0.12	2 types	8 methods	System.EnterpriseServices.IObjectContext
IObjectContextInfo	0.4	1 type	5 methods	System.EnterpriseServices .IObjectContextInfo
IObjectContextInfo2	0.38	1 type	8 methods	System.EnterpriseServices .IObjectContextInfo2
IObjectControl	0	2 types	3 methods	System.EnterpriseServices.IObjectControl
ITransactionProxy	0	1 type	7 methods	System.EnterpriseServices .ITransactionProxy
ITransactionVoterBallotAsync2	0	1 type	1 method	System.EnterpriseServices .ITransactionVoterBallotAsync2
ITransactionVoterNotifyAsync2	0.4	2 types	5 methods	System.EnterpriseServices .ITransactionVoterNotifyAsync2
ISharedProperty	0.5	2 types	2 methods	System.EnterpriseServices .ISharedProperty
ISharedPropertyGroup	0.5	2 types	4 methods	System.EnterpriseServices .ISharedPropertyGroup
ISharedPropertyGroupManager	1	1 type	3 methods	System.EnterpriseServices .ISharedPropertyGroupManager
IManagedObject	0	3 types	2 methods	System.EnterpriseServices.IManagedObject
IContext	0.33	1 type	3 methods	System.EnterpriseServices.IContext
IManagedObjectInfo	0	1 type	4 methods	System.EnterpriseServices .IManagedObjectInfo
ITransactionProperty	0.077	1 type	13 methods	System.EnterpriseServices .ITransactionProperty
ISecurityCallersColl	0.5	2 types	3 methods	System.EnterpriseServices .ISecurityCallersColl
ISecurityIdentityColl	0.11	3 types	3 methods	System.EnterpriseServices .ISecurityIdentityColl
ISecurityCallContext	0.33	2 types	6 methods	System.EnterpriseServices .ISecurityCallContext
IConfigurationAttribute	0.83	2 types	3 methods	System.EnterpriseServices .IConfigurationAttribute
ICreateTypeLib	0.1	1 type	10 methods	System.EnterpriseServices.ICreateTypeLib
IConfigCallback	1	1 type	6 methods	System.EnterpriseServices .IConfigCallback
ITransactionResourcePool	1	1 type	2 methods	System.EnterpriseServices .ITransactionResourcePool
ICreateWithTipTransactionEx	1	1 type	1 method	System.EnterpriseServices .ICreateWithTipTransactionEx
ICreateWithTransactionEx	1	1 type	1 method	System.EnterpriseServices .ICreateWithTransactionEx
ICreateWithLocalTransaction	1	1 type	1 method	System.EnterpriseServices .ICreateWithLocalTransaction
IAssemblyCache	0.4	1 type	5 methods	System.EnterpriseServices.Internal .IAssemblyCache
ITypeLib2	0.071	1 type	14 methods	System.EnterpriseServices.Internal .ITypeLib2
IFormatLogRecords	1	1 type	3 methods	System.EnterpriseServices .CompensatingResourceManager .IFormatLogRecords
_IMonitorClerks	0.43	2 types	7 methods	System.EnterpriseServices .CompensatingResourceManager ._IMonitorClerks
ICatalog	0.12	1 type	26 methods	System.EnterpriseServices.Admin.ICatalog
ICatalogObject	0.21	29 types	7 methods	System.EnterpriseServices.Admin .ICatalogObject
ICatalogCollection	0.26	7 types	16 methods	System.EnterpriseServices.Admin .ICatalogCollection
IThunkInstallation	1	1 type	1 method	System.EnterpriseServices.Thunk .IThunkInstallation
IProxyInvoke	0.5	1 type	2 methods	System.EnterpriseServices.Thunk .IProxyInvoke
IDispatch	0.21	6 types	4 methods	System.Dynamic.IDispatch
IProvideClassInfo	1	1 type	1 method	System.Dynamic.IProvideClassInfo
ISystemColorTracker	1	1 type	1 method	System.Drawing.Internal .ISystemColorTracker
UnsafeNativeMethods+IMarshal	0	1 type	6 methods	Microsoft.Win32 .UnsafeNativeMethods+IMarshal
IInternetSecurityManager	0.12	2 types	8 methods	Microsoft.Win32.IInternetSecurityManager
IAuthenticationManager	1	1 type	14 methods	System.Net.IAuthenticationManager
IWebProxyFinder	1	1 type	4 methods	System.Net.IWebProxyFinder
IRequestLifetimeTracker	1	1 type	1 method	System.Net.IRequestLifetimeTracker
ISessionAuthenticationModule	0.67	1 type	3 methods	System.Net.ISessionAuthenticationModule
ICloseEx	1	6 types	1 method	System.Net.ICloseEx
SSPIInterface	0.2	5 types	21 methods	System.Net.SSPIInterface
IAutoWebProxy	1	1 type	1 method	System.Net.IAutoWebProxy
IEncodableStream	0.42	3 types	4 methods	System.Net.Mime.IEncodableStream
IMSAdminBase	0.13	1 type	31 methods	System.Net.Mail.IMSAdminBase
ISmtpAuthenticationModule	0.4	5 types	3 methods	System.Net.Mail .ISmtpAuthenticationModule
INotifyCollectionChangedEventArgs	1	1 type	5 methods	System.Runtime.InteropServices .WindowsRuntime .INotifyCollectionChangedEventArgs
IPropertyChangedEventArgs	1	1 type	1 method	System.Runtime.InteropServices .WindowsRuntime .IPropertyChangedEventArgs
INotifyCollectionChanged_WinRT	1	1 type	2 methods	System.Runtime.InteropServices .WindowsRuntime .INotifyCollectionChanged_WinRT
INotifyPropertyChanged_WinRT	1	1 type	2 methods	System.Runtime.InteropServices .WindowsRuntime .INotifyPropertyChanged_WinRT
ICommand_WinRT	1	1 type	4 methods	System.Runtime.InteropServices .WindowsRuntime.ICommand_WinRT
IDeflater	1	1 type	4 methods	System.IO.Compression.IDeflater
IInflater	0.6	1 type	5 methods	System.IO.Compression.IInflater
IFileFormatWriter	0.5	2 types	3 methods	System.IO.Compression.IFileFormatWriter
IFileFormatReader	0.33	3 types	4 methods	System.IO.Compression.IFileFormatReader
NativeComInterfaces+IAdsPathname	0.21	7 types	11 methods	System.DirectoryServices.ActiveDirectory .NativeComInterfaces+IAdsPathname
NativeComInterfaces+IAdsProperty	0.042	2 types	24 methods	System.DirectoryServices.ActiveDirectory .NativeComInterfaces+IAdsProperty
NativeComInterfaces+IAdsClass	0.058	2 types	43 methods	System.DirectoryServices.ActiveDirectory .NativeComInterfaces+IAdsClass
ILocationReport	0.67	1 type	3 methods	System.Device.Location.Internal .ILocationReport
ILatLongReport	0.62	1 type	8 methods	System.Device.Location.Internal .ILatLongReport
ILocation	0.67	1 type	9 methods	System.Device.Location.Internal .ILocation
IWizardStepEditableRegion	1	2 types	1 method	System.Web.UI.Design.WebControls .IWizardStepEditableRegion
IDesignConnection	0.046	14 types	14 methods	System.Data.Design.IDesignConnection
IDataSourceNamedObject	0	5 types	1 method	System.Data.Design .IDataSourceNamedObject
IDataSourceXmlSerializable	1	1 type	2 methods	System.Data.Design .IDataSourceXmlSerializable
IDataSourceXmlSpecialOwner	1	1 type	2 methods	System.Data.Design .IDataSourceXmlSpecialOwner
IDataSourceInitAfterLoading	1	1 type	1 method	System.Data.Design .IDataSourceInitAfterLoading
INamedObject	0.5	4 types	2 methods	System.Data.Design.INamedObject
INamedObjectCollection	0	3 types	1 method	System.Data.Design .INamedObjectCollection
INameService	0.083	8 types	6 methods	System.Data.Design.INameService
IEventHandlerService	0.18	11 types	6 methods	System.Windows.Forms.Design .IEventHandlerService
IMenuStatusHandler	1	1 type	2 methods	System.Windows.Forms.Design .IMenuStatusHandler
IMouseHandler	0.5	2 types	6 methods	System.Windows.Forms.Design .IMouseHandler
IOleDragClient	0.33	4 types	6 methods	System.Windows.Forms.Design .IOleDragClient
IOverlayService	0.32	5 types	5 methods	System.Windows.Forms.Design .IOverlayService
ISelectionUIHandler	0.5	2 types	13 methods	System.Windows.Forms.Design .ISelectionUIHandler
ISelectionUIService	0.11	5 types	20 methods	System.Windows.Forms.Design .ISelectionUIService
ISplitWindowService	0.5	2 types	2 methods	System.Windows.Forms.Design .ISplitWindowService
ISupportInSituService	0.33	3 types	3 methods	System.Windows.Forms.Design .ISupportInSituService
IClrStrongNameUsingIntPtr	0.24	1 type	25 methods	Microsoft.Runtime.Hosting .IClrStrongNameUsingIntPtr
IClrStrongName	0.36	1 type	25 methods	Microsoft.Runtime.Hosting.IClrStrongName
IEnumSTORE_ASSEMBLY_INSTALLATION_REFEREN CE	0	1 type	4 methods	System.Deployment.Internal.Isolation .IEnumSTORE_ASSEMBLY_INSTALLATION_REFERE NCE
IEnumSTORE_DEPLOYMENT_METADATA	0.17	3 types	4 methods	System.Deployment.Internal.Isolation .IEnumSTORE_DEPLOYMENT_METADATA
IEnumSTORE_DEPLOYMENT_METADATA_PROPERTY	0.17	3 types	4 methods	System.Deployment.Internal.Isolation .IEnumSTORE_DEPLOYMENT_METADATA_PROPERTY
IEnumSTORE_ASSEMBLY	0.17	3 types	4 methods	System.Deployment.Internal.Isolation .IEnumSTORE_ASSEMBLY
IEnumSTORE_ASSEMBLY_FILE	0.17	3 types	4 methods	System.Deployment.Internal.Isolation .IEnumSTORE_ASSEMBLY_FILE
IEnumSTORE_CATEGORY	0.17	3 types	4 methods	System.Deployment.Internal.Isolation .IEnumSTORE_CATEGORY
IEnumSTORE_CATEGORY_SUBCATEGORY	0.25	2 types	4 methods	System.Deployment.Internal.Isolation .IEnumSTORE_CATEGORY_SUBCATEGORY
IEnumSTORE_CATEGORY_INSTANCE	0.17	3 types	4 methods	System.Deployment.Internal.Isolation .IEnumSTORE_CATEGORY_INSTANCE
IReferenceIdentity	0.12	13 types	4 methods	System.Deployment.Internal.Isolation .IReferenceIdentity
IDefinitionIdentity	0.083	18 types	4 methods	System.Deployment.Internal.Isolation .IDefinitionIdentity
IEnumIDENTITY_ATTRIBUTE	0.2	2 types	5 methods	System.Deployment.Internal.Isolation .IEnumIDENTITY_ATTRIBUTE
IEnumDefinitionIdentity	0.25	4 types	4 methods	System.Deployment.Internal.Isolation .IEnumDefinitionIdentity
IEnumReferenceIdentity	0.25	2 types	4 methods	System.Deployment.Internal.Isolation .IEnumReferenceIdentity
IDefinitionAppId	0.083	20 types	6 methods	System.Deployment.Internal.Isolation .IDefinitionAppId
IReferenceAppId	0.2	5 types	5 methods	System.Deployment.Internal.Isolation .IReferenceAppId
IIdentityAuthority	0.22	3 types	18 methods	System.Deployment.Internal.Isolation .IIdentityAuthority
IAppIdAuthority	0.16	2 types	16 methods	System.Deployment.Internal.Isolation .IAppIdAuthority
IStore	0.19	5 types	20 methods	System.Deployment.Internal.Isolation .IStore
IManifestParseErrorCallback	0	2 types	1 method	System.Deployment.Internal.Isolation .IManifestParseErrorCallback
IManifestInformation	0.5	2 types	1 method	System.Deployment.Internal.Isolation .IManifestInformation
IActContext	0.22	3 types	18 methods	System.Deployment.Internal.Isolation .IActContext
IStateManager	0.25	1 type	4 methods	System.Deployment.Internal.Isolation .IStateManager
ISection	0.21	7 types	4 methods	System.Deployment.Internal.Isolation .ISection
ISectionWithStringKey	0.5	1 type	2 methods	System.Deployment.Internal.Isolation .ISectionWithStringKey
ISectionWithReferenceIdentityKey	1	1 type	1 method	System.Deployment.Internal.Isolation .ISectionWithReferenceIdentityKey
ISectionEntry	0	1 type	2 methods	System.Deployment.Internal.Isolation .ISectionEntry
IEnumUnknown	0.25	3 types	4 methods	System.Deployment.Internal.Isolation .IEnumUnknown
ICMS	0.064	5 types	22 methods	System.Deployment.Internal.Isolation .Manifest.ICMS
IHashElementEntry	0.14	2 types	7 methods	System.Deployment.Internal.Isolation .Manifest.IHashElementEntry
IFileEntry	0.067	1 type	15 methods	System.Deployment.Internal.Isolation .Manifest.IFileEntry
IFileAssociationEntry	0.17	1 type	6 methods	System.Deployment.Internal.Isolation .Manifest.IFileAssociationEntry
IAssemblyReferenceEntry	0.25	1 type	4 methods	System.Deployment.Internal.Isolation .Manifest.IAssemblyReferenceEntry
IEntryPointEntry	0.17	1 type	6 methods	System.Deployment.Internal.Isolation .Manifest.IEntryPointEntry
IDescriptionMetadataEntry	0.14	1 type	7 methods	System.Deployment.Internal.Isolation .Manifest.IDescriptionMetadataEntry
IDeploymentMetadataEntry	0.17	1 type	6 methods	System.Deployment.Internal.Isolation .Manifest.IDeploymentMetadataEntry
IDependentOSMetadataEntry	0.12	1 type	8 methods	System.Deployment.Internal.Isolation .Manifest.IDependentOSMetadataEntry
ICompatibleFrameworksMetadataEntry	0.5	1 type	2 methods	System.Deployment.Internal.Isolation .Manifest .ICompatibleFrameworksMetadataEntry
IMetadataSectionEntry	0.33	1 type	21 methods	System.Deployment.Internal.Isolation .Manifest.IMetadataSectionEntry
ICompatibleFrameworkEntry	0.2	1 type	5 methods	System.Deployment.Internal.Isolation .Manifest.ICompatibleFrameworkEntry
IManagedDeploymentServiceCom	0	2 types	7 methods	System.Deployment.Application .IManagedDeploymentServiceCom
IDownloadNotification	0	2 types	2 methods	System.Deployment.Application .IDownloadNotification
IMetaDataDispenser	0.33	1 type	3 methods	System.Deployment.Application .IMetaDataDispenser
IMetaDataImport	0	1 type	62 methods	System.Deployment.Application .IMetaDataImport
IMetaDataAssemblyImport	0.5	1 type	14 methods	System.Deployment.Application .IMetaDataAssemblyImport
NativeMethods+IAssemblyCache	0.05	4 types	5 methods	System.Deployment.Application .NativeMethods+IAssemblyCache
NativeMethods+IAssemblyEnum	0.17	2 types	3 methods	System.Deployment.Application .NativeMethods+IAssemblyEnum
NativeMethods+IApplicationContext	0	2 types	5 methods	System.Deployment.Application .NativeMethods+IApplicationContext
NativeMethods+IAssemblyName	0	2 types	9 methods	System.Deployment.Application .NativeMethods+IAssemblyName
NativeMethods+ICorRuntimeHost	0.026	2 types	19 methods	System.Deployment.Application .NativeMethods+ICorRuntimeHost
ISourceLineInfo	0.22	18 types	4 methods	System.Xml.Xsl.ISourceLineInfo
IErrorHelper	0.38	4 types	2 methods	System.Xml.Xsl.IErrorHelper
IXPathBuilder<Node>	0.6	3 types	10 methods	System.Xml.Xsl.XPath.IXPathBuilder<Node>
IFocus	0.5	2 types	3 methods	System.Xml.Xsl.XPath.IFocus
IXPathEnvironment	0.38	2 types	4 methods	System.Xml.Xsl.XPath.IXPathEnvironment
IQilAnnotation	1	1 type	1 method	System.Xml.Xsl.Qil.IQilAnnotation
RecordOutput	0.2	5 types	2 methods	System.Xml.Xsl.XsltOld.RecordOutput
IStackFrame	0	1 type	5 methods	System.Xml.Xsl.XsltOld.Debugger .IStackFrame
IXsltProcessor	0	1 type	2 methods	System.Xml.Xsl.XsltOld.Debugger .IXsltProcessor
IXsltDebugger	0.12	8 types	3 methods	System.Xml.Xsl.XsltOld.Debugger .IXsltDebugger
IDataService	0.12	28 types	15 methods	System.Data.Services.IDataService
IProjectedResult	0.5	2 types	2 methods	System.Data.Services.IProjectedResult
OperationSignatures+ILogicalSignatures	0	2 types	3 methods	System.Data.Services.Parsing .OperationSignatures+ILogicalSignatures
OperationSignatures+IArithmeticSignature s	0	2 types	11 methods	System.Data.Services.Parsing .OperationSignatures+IArithmeticSignatur es
OperationSignatures+IRelationalSignature s	0	2 types	9 methods	System.Data.Services.Parsing .OperationSignatures+IRelationalSignatur es
OperationSignatures+INegationSignatures	0	2 types	11 methods	System.Data.Services.Parsing .OperationSignatures+INegationSignatures
OperationSignatures+INotSignatures	0	2 types	3 methods	System.Data.Services.Parsing .OperationSignatures+INotSignatures
OperationSignatures+IEnumerableSignature s	0	1 type	28 methods	System.Data.Services.Parsing .OperationSignatures+IEnumerableSignatur es
IExceptionWriter	0.5	2 types	1 method	System.Data.Services.Serializers .IExceptionWriter
IProjectionProvider	0.5	2 types	1 method	System.Data.Services.Providers .IProjectionProvider
IDataServices	0.21	8 types	7 methods	System.Data.Linq.Provider.IDataServices
IDeferredSourceFactory	0.25	2 types	2 methods	System.Data.Linq.Provider .IDeferredSourceFactory
IProvider	0.14	10 types	18 methods	System.Data.Linq.Provider.IProvider
ICompiledQuery	0.67	3 types	1 method	System.Data.Linq.Provider.ICompiledQuery
IConnectionManager	0.25	2 types	2 methods	System.Data.Linq.SqlClient .IConnectionManager
IConnectionUser	1	1 type	1 method	System.Data.Linq.SqlClient .IConnectionUser
IObjectReader	0.33	3 types	1 method	System.Data.Linq.SqlClient.IObjectReader
IObjectReaderSession	0.17	6 types	2 methods	System.Data.Linq.SqlClient .IObjectReaderSession
IReaderProvider	0.17	3 types	2 methods	System.Data.Linq.SqlClient .IReaderProvider
IObjectReaderFactory	0.14	7 types	2 methods	System.Data.Linq.SqlClient .IObjectReaderFactory
IObjectReaderCompiler	1	1 type	2 methods	System.Data.Linq.SqlClient .IObjectReaderCompiler
ICompiledSubQuery	0	6 types	1 method	System.Data.Linq.SqlClient .ICompiledSubQuery
IEntityStateManager	0.3	4 types	5 methods	System.Data.IEntityStateManager
IEntityStateEntry	0.11	25 types	14 methods	System.Data.IEntityStateEntry
IEntityAdapter	0.33	3 types	7 methods	System.Data.IEntityAdapter
ISqlFragment	0.33	3 types	1 method	System.Data.SqlClient.SqlGen .ISqlFragment
IDbSpatialValue	0.5	4 types	8 methods	System.Data.SqlClient.Internal .IDbSpatialValue
IObjectView	1	1 type	2 methods	System.Data.Objects.IObjectView
IObjectViewData<T>	0.33	3 types	13 methods	System.Data.Objects.IObjectViewData<T>
IChangeTrackingStrategy	0	4 types	4 methods	System.Data.Objects.Internal .IChangeTrackingStrategy
IEntityKeyStrategy	0	4 types	3 methods	System.Data.Objects.Internal .IEntityKeyStrategy
IPropertyAccessorStrategy	0	4 types	5 methods	System.Data.Objects.Internal .IPropertyAccessorStrategy
IEntityWrapper	0.13	21 types	29 methods	System.Data.Objects.Internal .IEntityWrapper
IRelationshipFixer	0.33	3 types	1 method	System.Data.Objects.DataClasses .IRelationshipFixer
IBaseList<T>	0.18	19 types	3 methods	System.Data.Metadata.Edm.IBaseList<T>
ITileQuery	1	1 type	1 method	System.Data.Mapping.ViewGeneration .QueryRewriting.ITileQuery
IRelationship	0.24	9 types	7 methods	System.Data.EntityModel .SchemaObjectModel.IRelationship
IRelationshipEnd	0.3	10 types	5 methods	System.Data.EntityModel .SchemaObjectModel.IRelationshipEnd
ISchemaElementLookUpTable<T>	0.25	4 types	5 methods	System.Data.EntityModel .SchemaObjectModel .ISchemaElementLookUpTable<T>
IGroupExpressionExtendedInfo	1	1 type	2 methods	System.Data.Common.EntitySql .IGroupExpressionExtendedInfo
IGetAlternativeName	1	1 type	1 method	System.Data.Common.EntitySql .IGetAlternativeName
ITypedGetters	0	3 types	35 methods	Microsoft.SqlServer.Server.ITypedGetters
ITypedGettersV3	0.11	10 types	17 methods	Microsoft.SqlServer.Server .ITypedGettersV3
ITypedSettersV3	0.2	5 types	17 methods	Microsoft.SqlServer.Server .ITypedSettersV3
IXmlDataVirtualNode	0.75	1 type	4 methods	System.Xml.IXmlDataVirtualNode
IFilter	0.11	9 types	1 method	System.Data.IFilter
NativeMethods+ISourcesRowset	0.5	2 types	1 method	System.Data.Common .NativeMethods+ISourcesRowset
NativeMethods+ITransactionJoin	0.17	3 types	2 methods	System.Data.Common .NativeMethods+ITransactionJoin
UnsafeNativeMethods+ADORecordConstructio n	0.5	2 types	1 method	System.Data.Common .UnsafeNativeMethods+ADORecordConstructi on
UnsafeNativeMethods+ADORecordsetConstruc tion	0.33	2 types	3 methods	System.Data.Common .UnsafeNativeMethods+ADORecordsetConstru ction
UnsafeNativeMethods+Recordset15	0.027	2 types	55 methods	System.Data.Common .UnsafeNativeMethods+Recordset15
UnsafeNativeMethods+_ADORecord	0.031	2 types	16 methods	System.Data.Common .UnsafeNativeMethods+_ADORecord
UnsafeNativeMethods+IAccessor	0.1	5 types	4 methods	System.Data.Common .UnsafeNativeMethods+IAccessor
UnsafeNativeMethods+IChapteredRowset	0.25	2 types	2 methods	System.Data.Common .UnsafeNativeMethods+IChapteredRowset
UnsafeNativeMethods+IColumnsInfo	0.33	3 types	1 method	System.Data.Common .UnsafeNativeMethods+IColumnsInfo
UnsafeNativeMethods+IColumnsRowset	0.33	3 types	2 methods	System.Data.Common .UnsafeNativeMethods+IColumnsRowset
UnsafeNativeMethods+ICommandPrepare	0.5	2 types	1 method	System.Data.Common .UnsafeNativeMethods+ICommandPrepare
UnsafeNativeMethods+ICommandProperties	0.33	3 types	2 methods	System.Data.Common .UnsafeNativeMethods+ICommandProperties
UnsafeNativeMethods+ICommandText	0.15	4 types	5 methods	System.Data.Common .UnsafeNativeMethods+ICommandText
UnsafeNativeMethods+ICommandWithParamete rs	0.17	2 types	3 methods	System.Data.Common .UnsafeNativeMethods+ICommandWithParamet ers
UnsafeNativeMethods+IDBInfo	0.25	4 types	2 methods	System.Data.Common .UnsafeNativeMethods+IDBInfo
UnsafeNativeMethods+IDBProperties	0.14	7 types	3 methods	System.Data.Common .UnsafeNativeMethods+IDBProperties
UnsafeNativeMethods+IDBSchemaRowset	0.2	5 types	2 methods	System.Data.Common .UnsafeNativeMethods+IDBSchemaRowset
UnsafeNativeMethods+IErrorInfo	0.21	8 types	3 methods	System.Data.Common .UnsafeNativeMethods+IErrorInfo
UnsafeNativeMethods+IErrorRecords	0.17	3 types	6 methods	System.Data.Common .UnsafeNativeMethods+IErrorRecords
UnsafeNativeMethods+IMultipleResults	0.33	3 types	1 method	System.Data.Common .UnsafeNativeMethods+IMultipleResults
UnsafeNativeMethods+IOpenRowset	0.33	3 types	1 method	System.Data.Common .UnsafeNativeMethods+IOpenRowset
UnsafeNativeMethods+IRow	0.5	2 types	1 method	System.Data.Common .UnsafeNativeMethods+IRow
UnsafeNativeMethods+IRowset	0.2	3 types	5 methods	System.Data.Common .UnsafeNativeMethods+IRowset
UnsafeNativeMethods+IRowsetInfo	0.33	3 types	2 methods	System.Data.Common .UnsafeNativeMethods+IRowsetInfo
UnsafeNativeMethods+ISQLErrorInfo	0.5	2 types	1 method	System.Data.Common .UnsafeNativeMethods+ISQLErrorInfo
UnsafeNativeMethods+ITransactionLocal	0.05	4 types	5 methods	System.Data.Common .UnsafeNativeMethods+ITransactionLocal
ICngSymmetricAlgorithm	1	1 type	13 methods	Internal.Cryptography .ICngSymmetricAlgorithm
IIListProvider<TElement>	0.33	1 type	3 methods	System.Linq.IIListProvider<TElement>
IParallelPartitionable<T>	1	1 type	1 method	System.Linq.Parallel .IParallelPartitionable<T>
IMergeHelper<TInputOutput>	1	1 type	3 methods	System.Linq.Parallel.IMergeHelper <TInputOutput>
IPartitionedStreamRecipient<TElement>	0.94	34 types	1 method	System.Linq.Parallel .IPartitionedStreamRecipient<TElement>
IAttributedImport	0.33	3 types	6 methods	System.ComponentModel.Composition .IAttributedImport
IReflectionPartCreationInfo	0.33	3 types	8 methods	System.ComponentModel.Composition .ReflectionModel .IReflectionPartCreationInfo
IPartCreatorImportDefinition	1	5 types	1 method	System.ComponentModel.Composition .Primitives.IPartCreatorImportDefinition
FilteredCatalog+IComposablePartCatalogTr aversal	1	1 type	2 methods	System.ComponentModel.Composition .Hosting .FilteredCatalog+IComposablePartCatalogT raversal
IActivityDelegateFactory	1	1 type	2 methods	System.Activities.Presentation .IActivityDelegateFactory
IExpandChild	0	1 type	1 method	System.Activities.Presentation .IExpandChild
IAutoSplitContainer	1	1 type	2 methods	System.Activities.Presentation .FreeFormEditing.IAutoSplitContainer
INestedFreeFormPanelContainer	0.75	2 types	2 methods	System.Activities.Presentation .FreeFormEditing .INestedFreeFormPanelContainer
IAutoConnectContainer	0.33	3 types	2 methods	System.Activities.Presentation .FreeFormEditing.IAutoConnectContainer
IAnnotationVisualProvider	0.25	4 types	3 methods	System.Activities.Presentation .Annotations.IAnnotationVisualProvider
IAnnotationIndicator	0.2	5 types	4 methods	System.Activities.Presentation .Annotations.IAnnotationIndicator
IDockedAnnotation	0.25	4 types	5 methods	System.Activities.Presentation .Annotations.IDockedAnnotation
IFloatingAnnotation	0.23	4 types	13 methods	System.Activities.Presentation .Annotations.IFloatingAnnotation
IValidationErrorSourceLocator	0.33	3 types	2 methods	System.Activities.Presentation .Validation .IValidationErrorSourceLocator
IItemsCollection	0.5	1 type	4 methods	System.Activities.Presentation.Model .IItemsCollection
IModelTreeItem	0.14	27 types	12 methods	System.Activities.Presentation.Model .IModelTreeItem
IPropertyViewManager	0.22	3 types	6 methods	System.Activities.Presentation.Internal .PropertyEditing.Views .IPropertyViewManager
ISelectionPathInterpreter	1	1 type	2 methods	System.Activities.Presentation.Internal .PropertyEditing.Selection .ISelectionPathInterpreter
ISelectionStop	0.27	6 types	5 methods	System.Activities.Presentation.Internal .PropertyEditing.Selection .ISelectionStop
IStateContainer	1	1 type	2 methods	System.Activities.Presentation.Internal .PropertyEditing.State.IStateContainer
IAutomationFocusChangedEventSource	1	2 types	1 method	System.Activities.Presentation.Internal .PropertyEditing.Automation .IAutomationFocusChangedEventSource
IMessageLogger	0.22	3 types	3 methods	System.Activities.Presentation.Internal .PropertyEditing.FromExpression .Framework.IMessageLogger
IIconProvider	1	1 type	1 method	System.Activities.Presentation.Internal .PropertyEditing.FromExpression .Framework.ValueEditors.IIconProvider
IPropertyInspector	0.25	2 types	2 methods	System.Activities.Presentation.Internal .PropertyEditing.FromExpression .Framework.PropertyInspector .IPropertyInspector
IVersionEditor	1	1 type	1 method	System.Activities.Presentation.View .IVersionEditor
ITreeViewItemSelectionHandler	0.5	3 types	2 methods	System.Activities.Presentation.View .TreeView.ITreeViewItemSelectionHandler
IWorkflowDesignerXamlHelperExecutionCont ext	1	1 type	10 methods	Microsoft.Activities.Presentation.Xaml .IWorkflowDesignerXamlHelperExecutionCon text
ILoadRetryStrategy	0.5	2 types	1 method	System.Activities.DurableInstancing .ILoadRetryStrategy
IObjectSerializer	0.35	5 types	4 methods	System.Activities.DurableInstancing .IObjectSerializer
IAsyncCodeActivity	1	1 type	1 method	System.Activities.IAsyncCodeActivity
IDynamicActivity	0.33	2 types	3 methods	System.Activities.IDynamicActivity
ILocationReferenceExpression	1	1 type	1 method	System.Activities.Expressions .ILocationReferenceExpression
ILocationReferenceWrapper	1	3 types	1 method	System.Activities.Expressions .ILocationReferenceWrapper
DynamicUpdateMapBuilder+IDefinitionMatch er	0.25	4 types	4 methods	System.Activities.DynamicUpdate .DynamicUpdateMapBuilder+IDefinitionMatc her
IInstanceUpdatable	1	1 type	1 method	System.Activities.DynamicUpdate .IInstanceUpdatable
IFlowSwitch	1	1 type	2 methods	System.Activities.Statements.IFlowSwitch
ICaseKeyBoxView	0.88	1 type	8 methods	System.Activities.Core.Presentation .ICaseKeyBoxView
IFlowSwitchLink	0.33	2 types	9 methods	System.Activities.Core.Presentation .IFlowSwitchLink
IFlowSwitchDefaultLink	1	1 type	2 methods	System.Activities.Core.Presentation .IFlowSwitchDefaultLink
IActivationService	0.5	2 types	5 methods	System.ServiceModel.Activation .IActivationService
IActivatedMessageQueue	0.33	3 types	9 methods	System.ServiceModel.Activation .IActivatedMessageQueue
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IApplicationContext	0	2 types	5 methods	Microsoft.Win32.IApplicationContext
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IClrStrongName	0.36	1 type	25 methods	Microsoft.Runtime.Hosting.IClrStrongName
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Are SOLID principles Cargo Cult?

My last post about SOLID Design: The Single Responsibility Principle (SRP) generated some discussion on reddit. The discussion originated from a remark considering SOLID principles as a Cargo Cult. Taking account the definition of Cargo Cult the metaphor is a bit provocative but it is not unfounded.

A cargo cult is a belief system among members of a relatively undeveloped society in which adherents practice superstitious rituals hoping to bring modern goods supplied by a more technologically advanced society

The recent Boeing’s 737 Max fiasco revealed that some parts of their software have been outsourced to $9-an-hour engineers. Those engineers shouldn’t be blamed for not achieving top notch software taking account the budget. Nevertheless it is clear that a lot of software written nowadays look like this cargo cult plane. For many real-world developers, SOLID principles are superstitious rituals whose primary goal is to succeed during job interview.

The SRP article underlines that SRP is the only SOLID principle not related to the usage of abstraction and polymorphism. SRP is about logic partitioning into code: which logic should be declared in which class. But SRP is so vague it is practically useless from its two definitions.

Definition 1: A class should have a single responsibility and this responsibility should be entirely encapsulated by the class.

Definition 2: A class should have one reason to change.

One can justify any class design choice by tweaking somehow what is a responsibility or what is a reason to change. In other words, as someone wrote in comment: Most people who “practice” it don’t actually know what it means and use it as an excuse to do whatever the hell they were going to do anyways.

We can feel bitterness in those comments, certainly coming from seasoned developers whose job is to fix mistakes of $9 an hour engineers.

SOLID Principles vs. OOP Patterns

We must remember that SOLID principles emerged in the 80s and 90s from the work of world-class OOP experts like Robert C. Martin (Uncle Bob) and Bertrand Meyer. Software writing is often considered as an art. Terminologies such as clean code or beautiful code have been widely used. But art is a subjective activity. In this context, SOLID principles necessarily remain vague and subject to interpretation. And this is what makes the difference between a SOLID principle and an OOP pattern:

A SOLID Principle is subjective. It helps to guide the usage of powerful concepts of Object Oriented Programming (OOP).
An OOP Pattern is objective. It is a set of recipes to implement a well identified situation with the OOP concepts.

Despite a restraint number of keywords and operators, the OOP toolbelt of languages such as C# or Java is very rich. With a few dozens of characters it is possible to write code that puzzle experts. C# especially gets richer and richer with many syntactic sugars to express complex situations with just a few characters. This power is a double edged sword: seasoned developers can write neat and compact code. But on the other hand it is easy to misuse this power, especially for junior developers and all those that write code just to pay their bills.

Always keep in mind the KISS principle

Someone wrote in comments: “SOLID encourages abstraction, and abstraction increases complexity. It’s not always worth it, but it’s always presented as the non-plus ultra of good approaches.”

The only reason to be for abstraction in OOP is to simplify the implementation of a complex business rule.

Abstracting Circle, Rectangle and Triangle with an IShape interface will dramatically simplify the implementation of a shape drawing software.
On the other hand, creating an interface for each class is a waste of resource: not every concepts in your program deserve an abstraction.

This is why the Keep It Simple Stupid KISS principle should be always kept in mind: don’t add up extra implementation complexity on top of the business complexity.

SOLID and Static Analysis

I have been in the .NET static analysis industry since 2004. At that time I was consulting for large companies with massive legacy apps that were very costly to maintain. Books like Robert Martin’s Agile Principles, Patterns, and Practices made me realize that the source code is data. This data can be measured with code metrics. And the same way relational data can be crawled with SQL queries, code as data can be crawled with code queries. For example:

from m in Application.Methods  
where m.CyclomatiComplexity > 15 && m.PercentageCoverage < 100
select new { m, m.CyclomatiComplexity, m.PercentageCoverage }

from m in Application.Methods

where m.CyclomatiComplexity > 15 && m.PercentageCoverage < 100

select new { m, m.CyclomatiComplexity, m.PercentageCoverage }

This query will objectively match complex methods not fully covered by tests. There are situations where one can argue that static analysis returns false positives but there is no justification for complex methods not well tested.

Not all aspects of SOLID principles can be objectively measured and verified. However static analysis can help bring objectiveness. For example:

A class with many methods and fields and with a poor Lack of Cohesion Of Method (LCOM) score certainly has too many responsibilities.
A base class that uses some of its derivative is objectively a violation of the Open Close Principle (OCP).
A method that overrides a base method and that throws NotImplementedException or NotSupportedException is objectively a violation of the Liskov Substitution Principle.
An interface presenting a dozen of method is objectively a violation of the Interface Segregation Principle (ISP).
Some code metric exists to measure both coupling over implementations and over abstractions. Those metrics can help pinpoint violations of the Dependency Inversion Principle (DIP).

SOLID and Testability

Regularly applying such rules will avoid taking SOLID too far to the point it becomes detrimental. However there are still all those aspects of SOLID, and code design in general, that must be left to creativity and interpretation. Experience in software development helps a lot here: over the years one refines his/her gut feeling about which design will increase flexibility and maintainability.

By definition juniors developer have no experience. However anyone can relentlessly struggle for 100% code coverage by tests. Being able to fully cover your code means, by definition, that your code is testable. Testability doesn’t come by chance. The properties that leads to full testability are the same properties that leads to high maintainability. Those properties include:

Easiness to use API
Domain classes well isolated
Careful map of logic to classes
Short classes and short methods
Cohesive classes
Abstractions and polymorphism used judiciously
Careful management of states mutability

Advice to add up objectivity when applying SOLID principles

Not everyone is a senior developer with a passion for well designed code. As a consequence Cargo Cult usage of SOLID principles is common. To improve the design some objectivity needs to be added in the development process. Here are my 3 advices for that:

KISS principle first, always struggle for simplicity: if it is complicated it is not SOLID.
Use static analysis to automatically monitor some measurable aspects of SOLID. Gross violations of code quality rules and metrics are also SOLID principles violations.
Refactor your code until it becomes seamlessly 100% coverable by tests. Code that cannot be easily 100% covered by tests is not SOLID.

SOLID Design: The Single Responsibility Principle (SRP)

After having covered The Open-Close Principle (OCP) and The Liskov Substitution Principle (LSP) let’s talk about the Single Responsibility Principle (SRP) which is the S in the SOLID acronym. The SRP definition is:

A class should have a single responsibility and this responsibility should be entirely encapsulated by the class.

This leads to what is a responsibility in software design? There is no trivial answer, this is why Robert C. Martin (Uncle Bob) rewrote the SRP principle this way:

A class should have one reason to change.

This leads to what is a reason to change?

SRP is a principle that cannot be easily inferred from its definition. Moreover the SRP lets a lot of room for own opinions and interpretations. So what is SRP about? SRP is about logic partitioning into code: which logic should be declared in which class. Something to keep in mind is that SRP is the only SOLID principle not related to the usage of abstraction and polymorphism.

The goal of this post is to propose objective and concrete guidelines to increase your classes compliance with SRP, and in-fine, increase the maintainability of your code.

SRP and Concerns

Typically the ActiveRecord pattern is used to exhibit a typical SRP violation. An ActiveRecord class has two responsibilities:

First an ActiveRecord object stores in-memory data retrieved from a relational database.
Second the record is active in the sense that data in-memory and data in the relational database are kept mirrored. For that, the CRUD (Create Read Update Delete) operations are implemented by the ActiveRecord.

To make things concrete an ActiveRecord class can look like that:

public class Employee {
   public string Name { get; set; }
   public string Address { get; set; }
   ...

   public static Employee LoadFromName(string name) {
      //below query will get only a value from DB
      string sqlQuery = "SELECT * FROM Employee WHERE Name = '" + name + "' LIMIT 1;";

      // get value from DB and fill this employee with obtained value
      Employee record = new Employee() { Name =  name, Address = ...};
      return record;
   }

   public bool Create() { 
      // create the record in DB
   }
   public bool Update() {
      // update the record in DB ...
   }
   public bool Delete() { 
      // delete the record in DB ...
   }
}

public class Employee {

public string Name { get; set; }

public string Address { get; set; }

...

public static Employee LoadFromName(string name) {

//below query will get only a value from DB

string sqlQuery = "SELECT * FROM Employee WHERE Name = '" + name + "' LIMIT 1;";

// get value from DB and fill this employee with obtained value

Employee record = new Employee() { Name = name, Address = ...};

return record;

}

public bool Create() {

// create the record in DB

}

public bool Update() {

// update the record in DB ...

}

public bool Delete() {

// delete the record in DB ...

}

If Employee was a POCO class that doesn’t know about persistence and if the persistence was handled in a dedicated persistence layer the API would be improved because:

Not all Employee consumer wants to deal with persistence.
More importantly an Employee consumer really needs to know when an expensive DB roundtrip is triggered: if the Employee class is responsible for the persistence who knows if the data is persisted as soon as a setter is invoked?

Hence better isolate the persistence layer accesses and make them more explicit. This is why at NDepend we promote rules like UI layer shouldn’t use directly DB types that can be easily adapted to enforce any sort of code isolation.

Persistence is what we call a cross-cutting concerns, an aspect of the implementation that tends to spawn all over the code. We can expect that most domain objects are concerned with persistence. Other cross-cutting-concerns we want to separate domain objects from include: validation, log, authentication, error handling, threading, caching. The need to separate domain entities from those cross-cutting concerns can be handled by some OOP pattern like the pattern decorator for example. Alternatively some Object-Relational Mapping (ORM) frameworks and some Aspect-Oriented-Programming (AOP) frameworks can be used.

SRP and Reason to Change

Let’s consider this version of Employee:

public class Employee { 
  public string Name { get; set; }
  public string Address { get; set; } 
  ...
  public void ComputePay() { ... }
  public void ReportHours() { ...}
}

public class Employee {

public string Name { get; set; }

public string Address { get; set; }

...

public void ComputePay() { ... }

public void ReportHours() { ...}

}

The ComputePay() behavior is under the responsibility of the finance people and the ReportHours() behavior is under the responsibility of the operational people. Hence if a financial person needs a change to be implemented in ComputePay() we can assume this change won’t affect the ReportHours() method. Thus according to the version of SRP that states “a class should have one reason to change”, it is wise to declare these methods in different dedicated modules. As a consequence a change in ComputePay() has no risk to affect the behavior of ReportHours() and vice-versa. In other words we want these two parts of the code to be independent because they will evolve independently.

This is why Robert C. Martin wrote that SRP is about people : make sure that logics controlled by different people are implemented in different modules.

SRP and High-Cohesion

The SRP is about encapsulating logic and data in a class because they fit well together. Fit well means that the class is cohesive in the sense that most methods use most fields. Actually cohesion of a class can be measured with the Lack of Cohesion Of Methods (LCOM) metric. See below an explanations of LCOM (extracted from this great Stuart Celarier placemat) What matters is to understand that if all methods of a class are using all instances fields, the class is considered utterly cohesive and has the best LCOM score, which is 0 or close to 0.

Typically the effect of a SRP violation is to partition a class methods and fields into groups with few connections. The fields needed to compute the pay of an employee are not the same than the fields needed to report pending work. This is why the LCOM metric can be used to measure adherence to SRP and take actions. You can use the rule Avoid types with poor cohesion to track classes with poor cohesion between methods and fields.

SRP and Fat Code Smells

While we can hardly find an easy definition for what is a responsibility we noticed that adhering to SRP usually results in classes with a good LCOM score. On the other hand, not adhering to SRP usually leads to the God class phenomenon: a class that knows too much and does too much. Such god class is usually too large: violations of rules like Avoid types too big, Avoid types with too many methods, Avoid types with too many fields are good candidate to spot god classes and refactor into a finer-grained design.

Guidelines to adhere to SRP

Here are a set of objective and concrete guidelines to adhere to SRP:

Domain classes must be isolated from Cross-Cutting Concerns: code responsible for persistence, validation, log, authentication, error handling, threading, caching…
When implementing your domain, favor POCO classes that do not have any dependency on an external framework. Note that a POCO class is not necessarily a fields and properties only class, but can implement logic/behavior related to its data.
Use your understanding of the Domain to partition code: logics related to different business functions should be kept separated to avoid interference.
Regularly check the Lack of Cohesion Of Methods (LCOM) score of your classes.
Regularly check for too large and too complex classes.

Continuing Our Clean Architecture Example in C#

After a somewhat long delay, it’s time to finally continue our series on clean architecture. This is the second post in the inner series in which we show you a quick implementation of said architecture and the third post in the overall series. In case you haven’t read the previous posts, please do so by using the links in the series layout below:

An Introduction To Clean Architecture
- A Clean Architecture Example in C#
- A Clean Architecture Example in C#, part 2 (this post)

Without further ado, let’s continue our implementation.

Continue reading Continuing Our Clean Architecture Example in C#

How to Measure Lines of Code? Let’s Count the Ways

There are a few ways to count lines of code, and they each have their advantages and disadvantages.

Much of the differences come down to defining what a “line” is. Is a line a literal line in the source file, a logical statement in the language we’re using, or an executable instruction?

Let’s take a look at three metrics:

Source lines of code—the number of lines of code in a method, skipping comments and blank lines
Logical lines of code—the number of statements, ignoring formatting and often counting a line as more than one statement
IL instructions—the number of instructions that the code compiles to

Is one better than the other? It depends on what you’re trying to measure.

Continue reading How to Measure Lines of Code? Let’s Count the Ways

Functional Programming Makes Your Code Not OO…And That’s It

Over the course of the fall and winter, I’ve been gaining momentum with code research posts. Today, I bring that momentum to bear on the subject of functional programming. Or at least, on functional style of programming in C# codebases.

But before I do that, let me provide a little background in case you haven’t caught the previous posts in the series. It started with me doing automated static analysis on 100 codebases to see how singletons impact those codebases. Next up, I used that data to look at how unit tests affect codebases. That post generated a lot of buzz, so I enlisted a partner to help with statistical analysis and then boosted the codebase sample size up to 500.

At the end of that last post, I suggested some future topics of study. Well, now I’ve picked one: functional programming.

What Is Functional Programming?

The idea with this post is mostly to report on findings, but I’d be remiss if I didn’t provide at least some background so that anyone reading has some context. So first, let’s cover the topic of functional programming briefly.

Functional programming is one of the major programming paradigms. Specifically, its calling card is that it disallows side effects. In other words, it models the rules of math, in which the result of the function (or method) is purely a deterministic function of its inputs.

So, in pseudo-code, it looks like this:

public int Add(int x, int y)
{
  return x + y;
}

public int Add(int x, int y)

{

return x + y;

}

This is a functional method. But if you do something like this

public int Add(int x, int y)
{
  return GlobalVariable + x + y;
}

public int Add(int x, int y)

{

return GlobalVariable + x + y;

}

or like this

public int Add(int x, int y)
{
  _databasePlopper.plopResultInDatabase(x + y); 
  return x + y;
}

public int Add(int x, int y)

{

_databasePlopper.plopResultInDatabase(x + y);

return x + y;

}

then you’re out of the functional realm because you’re adding side effects. These two modified versions of Add() each concern themselves with the world beyond processing the inputs to add. (As an aside, you could “fix” this by passing the global variable or the _databasePlopper dependency to the method as a parameter.)

Now, take note of something because this matters to the rest of the post. While C# (or any other object-oriented language) is not a functional language, per se, you can write functional methods in C#.

Continue reading Functional Programming Makes Your Code Not OO…And That’s It

Unit Tests Correlate With Desirable Codebase Properties

Today, I give you the third post in a series about how unit tests affect codebases.

The first one wound up getting a lot of attention, which was fun. In it, I presented some analysis I’d done of about 100 codebases. I had formed hypotheses about how I thought unit tests would affect codebases, and then I tested those hypotheses.

In the second post, I incorporated a lot of the feedback that I had requested in the first post. Specifically, I partnered with someone to do more rigorous statistical analysis on the raw data that I’d found. The result was much more clarity about not only the correlations among code properties but also how much confidence we could have in those relationships. Some had strong relationships while others were likely spurious.

In this post, though, I’m incorporating the single biggest piece of feedback. I’m analyzing more codebases.

Analysis of 500 (ish) C# Codebases

Performing static analysis on and recording information about 500 codebases isn’t especially easy. To facilitate this, I’ve done significant work automating ingestion of codebases:

Enabling autonomous batch operation
Logging which codebases fail and why
Building in redundancy against accidentally analyzing the same codebase twice.
Executing not just builds but also NuGet package restores and other build steps.

That’s been a big help, but there’s still the matter of finding these codebases. To do that, I mined a handful of “awesome codebase” lists, like this one. I pointed the analysis tool at something like 750 codebases, and it naturally filters out any that don’t compile or otherwise have trouble in the automated process.

This left me with 503 valid codebases. That number came down to 495 once adjusted for codebases that, for whatever reason, didn’t have any (non-third party) methods or types or that were otherwise somehow trivial.

So the results here are the results of using NDepend for static analysis on 495 C# codebases.

Continue reading Unit Tests Correlate With Desirable Codebase Properties