Interface segregation Principal (ISP)

ISP States that no client should be forced to depend on methods it does not use. ISP is one of the five SOLID principles of Object-Oriented Design.

The below example i have create Imamals interface for Mamal features. Interface is having two features like canfeed, canSpeek . But CanSpeek in only applicable for Human . It is not required for Tiger Object. 

/// <summary>

    /// Mamal Features implemneted for Human

    /// </summary>

    public class Human : IMamals

    {

        public void CanFeed()

        {

            Console.WriteLine("Human Can Feed..");

        }

 

        public void CanSpeek()

        {

            Console.WriteLine("Human Can Speek..");

        }

    }

    /// <summary>

    /// Mamal Features implemneted for Tiger

    /// </summary>

    public class Tiger : IMamals

    {

        public void CanFeed()

        {

            Console.WriteLine("Tiger Can Feed..");

        }

 

        public void CanSpeek()

        {

            throw new NotImplementedException();

        }

    }

 

Human human = new Human();

            human.CanFeed();

            human.CanSpeek();

 

            Tiger tiger = new Tiger();

            tiger.CanFeed();

     tiger.CanSpeek();

ISP Implementation

 

We have already know the CanSpeek implementation in the ABOVE example. Here we split the Interface in two, one is for Common and another for Specific.

/// <summary>

    /// Interface For common

    /// </summary>

    public interface IMamalsCommon

    {

        void CanFeed();

      

    }

    /// <summary>

    /// Interface for Specific

    /// </summary>

    public interface IMamalsSpecific

    {

        void CanSpeek();

    }

 

 

    /// <summary>

    /// Mamal Features implemneted for Human

    /// </summary>

    public class Human : IMamalsCommon,IMamalsSpecific

    {

        public void CanFeed()

        {

            Console.WriteLine("Human Can Feed..");

        }

 

        public void CanSpeek()

        {

            Console.WriteLine("Human Can Speek..");

        }

    }

    /// <summary>

    /// Mamal Features implemneted for Tiger

    /// </summary>

    public class Tiger : IMamalsCommon

    {

        public void CanFeed()

        {

            Console.WriteLine("Tiger Can Feed..");

        }

 

    }

.

Human human = new Human();

            human.CanFeed();

            human.CanSpeek();

 

            Tiger tiger = new Tiger();

            tiger.CanFeed();

 

When an interface is implemented for a wide responsibility of members then there will be chance where some clients may have to implement members, which they don’t even use.