Design Patterns - Bridge

Design Patterns | Bridge

References
Example

References
- Definition: (source: http://en.wikipedia.org/wiki/Bridge_pattern)
  
  The intent of the bridge pattern is to "decouple an abstraction from its implementation so that the two can vary independently."
- Class diagram: (source: http://en.wikipedia.org/wiki/Bridge_pattern)

Example

The Implementor:

public interface Logger {
    void log();
}

The Concrete Implementor (1):

public class FileLogger implements Logger {
    public void log() {
        System.out.println("FileLogger-log");
    }
}

The Concrete Implementor (2):

public class ConsoleLogger implements Logger {
    public void log() {
        System.out.println("ConsoleLogger-log");
    }
}

The Abstraction:

public interface AbstractionLogger {
    void log();
}

The Refined Abstraction (1):

public class AbstractionFileLogger implements AbstractionLogger {
    private final Logger logger = new FileLogger();

    public void log() {
        logger.log();
    }
}

The Refined Abstraction (2):

public class AbstractionConsoleLogger implements AbstractionLogger {
    private final Logger logger = new ConsoleLogger();

    public void log() {
        logger.log();
    }
}

A simple class to test the Bridge design pattern:

public class BridgePatternTest {
    public static void main(String[] args) {
        // Example 1: File Logger
        final AbstractionLogger fileLogger = new AbstractionFileLogger();
        fileLogger.log();

        // Example 2: Console Logger
        final AbstractionLogger consoleLogger = new AbstractionConsoleLogger();
        consoleLogger.log();
    }
}