How to....

As I have decided to take a break from writing codes, time for some reading.  I am always interested in object oriented designs, I went back and started to study design patterns again. While I am reading I always make sure that I understand it properly so that I can make it easy for remember as I come back again. This time I started to forget what I have read before, so I thought I am going to write it in a blog so that I can quickly go through if I wanted to. In this blog I will write about Adapter pattern in OO design Patterns.

Adapter Pattern: “Converts the interface of a class into another interface clients expect. Lets classes work together that couldn’t otherwise because of incompatible interface.”

Let us try in a way that we should remember this patterns when we hear the name.

Say, I bought a computer from US but it only works with the American Socket. Here the plug and a computer is our client only understands AmericanSocket Interface. But I have a EuropeanSocket Interface. I build a EuropeanAdapter which takes a EuropeanSocket object.

       public interface AmericanSocket {

               public void optTwoPins();

               public void setPower();

    }

        public class kitchenSocket implements AmericanSocket {

         public void optTwoPins(){

            System.out.println(“I can opt for two pins”);

    }

          public void setPower(){

            System.out.println(“I can work with 120Volts ”);

     }

    }

Now here is EuropeanSocket

   public interface EuropeanSocket {

               public void optThreePins();

               public void setPower();

    }

        public class studySocket implements EuropeanSocket {

         public void setThreePins(){

            System.out.println(“I can opt for three pins ”);

    }

          public void setPower(){

            System.out.println(“I can work with 240Volts ”);

     }

    }

Here is the adapter:

public class EuropeanAdapter implements AmericanSocket{

    EuropeanSocket socket;

    public EuropeanAdapter(EuropeanSocket socket){

     this.socket = socket;

}

public void optTwoPins(){

socket.optThreePins();

}

public void setPower(){

// use a transformer to step down the power.

socket.setPower();

}

}

Now test it

public class AmericanComputer {

    public static void main(String[] args){

        EuropeanSocket socket = new StudySocket();

         AmericanSocket americansocket = new EuropeanAdapter(socket);

          americansocket.optTwoPins();

         americansocket.setPower();

}

}

My computer works now. My computer plug sees adapter as a American Socket.

Title always at the End.

How to remember Adapter Pattern