深入浅出设计模式七——Adapter模式(结构型)

 将两个不兼容的类或者说没有关系的类纠合在一起使用。就要在使用中间类，这个类即指适配器类。

如：有两种类打方形桩类和打圆形桩类。现在我们即需要打方形桩又需要打圆形桩。那么需要利用继承和组合的特性来创建适配器类。

package com.lwf.object.adapter;

public class SquarePeg {

	public void insert(String str){
		System.out.println("SquarePeg insert():" + str);
	}
}

 

 

package com.lwf.object.adapter;

public class RoundPeg {

	public void insertIntohole(String msg){
		System.out.println("RoundPeg insertIntohole():" + msg);
	}
}

 

 

package com.lwf.object.adapter;

public class PegAdapter extends SquarePeg {

	RoundPeg roundPeg = null;
	public PegAdapter(RoundPeg roundPeg){
		this.roundPeg = roundPeg;
	}
	
	public void insertHole(String msg){
		roundPeg.insertIntohole(msg);
	}
	public static void main(String[] args) {
		RoundPeg roundPeg = new RoundPeg();
		PegAdapter p = new PegAdapter(roundPeg);
		p.insert("sfjsljfsf");
		p.insertHole("hole");
	}
}

 

 

当我们需要继承来自多个类的特性的时候，结合面向接口编程的原则：

package com.lwf.object.adapter;

public interface iSquarePeg {
	public void insert(String str);
}

 

 

package com.lwf.object.adapter;

public interface iRoundPeg {
	public void insertIntohole(String msg);
}

 

package com.lwf.object.adapter;

public class SquarePeg implements iSquarePeg{

	public void insert(String str){
		System.out.println("SquarePeg insert():" + str);
	}
}

 

package com.lwf.object.adapter;

public class RoundPeg implements iRoundPeg{

	public void insertIntohole(String msg){
		System.out.println("RoundPeg insertIntohole():" + msg);
	}
}

 

package com.lwf.object.adapter;

public class PegAdapter implements iSquarePeg,iRoundPeg {

	private iSquarePeg iSquarePeg;
	private iRoundPeg iRoundPeg;
	
	public PegAdapter(iSquarePeg iSquarePeg,iRoundPeg iRoundPeg){
		this.iSquarePeg = iSquarePeg;
		this.iRoundPeg = iRoundPeg;
	}
	public void insert(String str){
		iSquarePeg.insert(str);
	}
	public void insertIntohole(String msg){
		iRoundPeg.insertIntohole(msg);
	}
	
	public static void main(String[] args) {
		iSquarePeg iSquarePeg = new SquarePeg();
		iRoundPeg iRoundPeg = new RoundPeg();
		PegAdapter p = new PegAdapter(iSquarePeg,iRoundPeg);
		p.insert("sfjsljfsf");
		p.insertIntohole("hole");
	}
}

  

图分别对应上面的两段代码.

对于采用继承和组合来完成的适配叫对象适配,就是UML的第一个图.

后面的叫类适配,UML图中的第二个图