桥接模式

public interface Sourceable {
	public void method();
}

public class SourceSub1 implements Sourceable {
	@Override
	public void method() {
		System.out.println("this is the first sub!");
	}
}

public class SourceSub2 implements Sourceable {
	@Override
	public void method() {
		System.out.println("this is the second sub!");
	}
}

定义一个桥，持有Sourceable的一个实例：

public abstract class Bridge {
	private Sourceable source;
	public void method(){
		source.method();
	}	
	public Sourceable getSource() {
		return source;
	}
	public void setSource(Sourceable source) {
		this.source = source;
	}
}

public class MyBridge extends Bridge {
	public void method(){
		getSource().method();
	}
}

public class BridgeTest {	
	public static void main(String[] args) {		
		Bridge bridge = new MyBridge();		
		/*调用第一个对象*/
		Sourceable source1 = new SourceSub1();
		bridge.setSource(source1);
		bridge.method();		
		/*调用第二个对象*/
		Sourceable source2 = new SourceSub2();
		bridge.setSource(source2);
		bridge.method();
	}
}

output：

this is the first sub!
this is the second sub!

这样，就通过对Bridge类的调用，实现了对接口Sourceable的实现类SourceSub1和SourceSub2的调用。接下来我再画个图，大家就应该明白了，因为这个图是我们JDBC连接的原理，有数据库学习基础的，一结合就都懂了。