Bridge Design Pattern

Bridge design pattern is one of the Structural design pattern. This is is used to decouple a class into two parts abstraction and it’s implementation. So that both can evolve in future without affecting each other. It increases the loose coupling between class abstraction and it’s implementation.

Example

FileUploaderAbstraction.java

package com.ashok.designpatterns.bridge;

/**
 * 
 * @author ashok.mariyala
 *
 */
public interface FileUploaderAbstraction {
   public Object upload(String path);

   public boolean store(Object object);
}

FileUploaderAbstractionImpl.java

package com.ashok.designpatterns.bridge;

/**
 * 
 * @author ashok.mariyala
 *
 */
public class FileUploaderAbstractionImpl implements FileUploaderAbstraction {

   private FileUploadImplementor provider = null;

   public FileUploaderAbstractionImpl(FileUploadImplementor provider) {
      super();
      this.provider = provider;
   }

   @Override
   public Object upload(String path) {
      return provider.uploadFile(path);
   }

   @Override
   public boolean store(Object object) {
      return provider.storeFile(object);
   }
}

FileUploadImplementor.java

package com.ashok.designpatterns.bridge;

/**
 * 
 * @author ashok.mariyala
 *
 */
public interface FileUploadImplementor {
   public Object uploadFile(String path);

   public boolean storeFile(Object object);
}

MacFileUploadImplementor.java

package com.ashok.designpatterns.bridge;

/**
 * 
 * @author ashok.mariyala
 *
 */
public class MacFileUploadImplementor implements FileUploadImplementor {
   @Override
   public Object uploadFile(String path) {
      return new Object();
   }

   @Override
   public boolean storeFile(Object object) {
      System.out.println("File upload successfully in Mac !!");
      return true;
   }
}

WondowsFileUploadImplementor.java

package com.ashok.designpatterns.bridge;

/**
 * 
 * @author ashok.mariyala
 *
 */
public class WondowsFileUploadImplementorimplements FileUploadImplementor {
   @Override
   public Object uploadFile(String path) {
      return new Object();
   }

   @Override
   public boolean storeFile(Object object) {
      System.out.println("File upload successfully in Windows !!");
      return true;
   }
}

TestBridgeDesignPattern.java

package com.ashok.designpatterns.bridge;

import java.util.Scanner;

public class TestBridgeDesignPattern {
   public static void main(String[] args) {
      Scanner scan = null;
      try {
         scan = new Scanner(System.in);
         System.out.print("Enter OS : ");
         String os = scan.next();
         FileUploaderAbstraction uploader = null;

         switch (os) {
            case "Windows":
               uploader = new FileUploaderAbstractionImpl(new WindowsFileUploadImplementor());
               break;

            case "Mac":
               uploader = new FileUploaderAbstractionImpl(new MacFileUploadImplementor());
               break;

            default:
               System.out.println("OS not supported !!");
         }

         Object fileContent = uploader.upload("/uploads/sample/");
         uploader.store(fileContent);
      } catch (Exception e) {
         e.printStackTrace();
      } finally {
         if (null != scan) {
            scan.close();
         }
      }
   }
}
Enter OS : Mac
File upload successfully in Mac !!

Bridge Design Pattern