6.原型模式(Prototype) +深度克隆

主要组成部分:抽象原型和具体原型类.

 

说明: 在Java中如果通过赋值语句来创建一个对象，则新对象和原来的对象同是一个引用用;Java已经帮我们提供了一种解决方法可以方使的克隆

类，这就是原型模式.

 

UML原理:

 

 

 

 

 

 

 

例子:

 

package com.prototype;

/**
 * 
 * @Title: KeyPrototype.java
 * @Description: 钥匙原型
 * @author [e-mail] 
 * @date 2010-6-3 
 * @version V1.0
 */
public class KeyPrototype implements Cloneable{
	private float length;
	private float thick;
	private String color;
	
	@Override
	protected Object clone() throws CloneNotSupportedException {
		
		Object obj = super.clone();
		return obj;
	}
	
	
	public float getLength() {
		return length;
	}
	public void setLength(float length) {
		this.length = length;
	}
	public float getThick() {
		return thick;
	}
	public void setThick(float thick) {
		this.thick = thick;
	}
	public String getColor() {
		return color;
	}
	public void setColor(String color) {
		this.color = color;
	}
	
	
	

}






package com.prototype;

/**
 * 
 * @Title: CopperKey.java
 * @Description: 铜钥匙
 * @author [e-mail] 
 * @date 2010-6-3 
 * @version V1.0
 */
public class CopperKey extends KeyPrototype{

	public CopperKey() {
		setColor("黄色");
	}

	
}




package com.prototype;

/**
 * 
 * @Title: AluminiumKey.java
 * @Description: 铝钥匙
 * @author [e-mail] 
 * @date 2010-6-3 
 * @version V1.0
 */
public class AluminiumKey extends KeyPrototype{

	public AluminiumKey() {
		setColor("银色");
	}

	
}




package com.prototype;

public class Client {
	
	public static void main(String[] args) throws CloneNotSupportedException {
		KeyPrototype copperKey = new CopperKey();
		copperKey.setLength(3.1f);
		copperKey.setThick(0.5f);
		
		KeyPrototype aluminiumKey = (KeyPrototype)copperKey.clone();
		aluminiumKey.setColor("银色");
		
		System.out.println("铜钥匙的颜色: "+ copperKey.getColor());
		System.out.println(copperKey.getLength());
		System.out.println("银钥匙的颜色： " + aluminiumKey.getColor());
		System.out.println(copperKey.getLength());
	}

}

 

 

 

有关深度克隆例子:

 

 

package com.prototype2;

public class Dog{
	private int legCounts;
	
	public Dog(int lenCounts){
		this.legCounts = lenCounts;
	}
	
	public void changeLegCounts(){
		this.legCounts *=2;
		
	}
	
	@Override
	public String toString(){
		return Integer.toString(this.legCounts);
	}

	
	
	

}





package com.prototype2;

public class DogClone implements Cloneable {
	
	public int  legCounts;
	public Dog dog = new Dog(4);
	
	

	@Override
	protected Object clone() throws CloneNotSupportedException {
		DogClone o = (DogClone)super.clone();
		
		return o;
	}
	

}




package com.prototype2;

public class Client {
	
	public static void main(String[] args) throws CloneNotSupportedException{
		DogClone dogClone = new DogClone();
		dogClone.legCounts = 3;
		System.out.println("原来的克隆狗的腿数量: " + dogClone.legCounts);
		System.out.println("原来克隆的那条狗数量: " + dogClone.dog);
		
		DogClone dogClone1 = (DogClone)dogClone.clone();
//		System.out.println(dogClone.dog);
		dogClone1.legCounts = 2;
		Dog dog = dogClone1.dog;
		dog.changeLegCounts();//改变数量*2
		System.out.println("克隆后原来狗的腿的数量: " + dogClone.legCounts);
		//这里变成了8这并不是我们想要的，我只是复制了表层信息
		System.out.println("克隆后原来那条狗数量:" + dogClone.dog);
		
	}
}

 

 

注意到最后打印,克隆后原来那条狗数量:8,所以Dog并没有真的被复制，可以这样做：

 

让Dog也实现Cloneable 同时改变DogClone的clone方法

 

package com.prototype2;

public class Dog implements Cloneable {
	private int legCounts;
	
	public Dog(int lenCounts){
		this.legCounts = lenCounts;
	}
	
	public void changeLegCounts(){
		this.legCounts *=2;
		
	}
	
	@Override
	public String toString(){
		return Integer.toString(this.legCounts);
	}

	@Override
	protected Object clone() throws CloneNotSupportedException {
		Dog o = (Dog)super.clone();
		return o;
	}

	

}

 

 

 

package com.prototype2;

public class DogClone implements Cloneable {
	
	public int  legCounts;
	public Dog dog = new Dog(4);
	
	

	@Override
	protected Object clone() throws CloneNotSupportedException {
		DogClone o = (DogClone)super.clone();
		o.dog = (Dog)dog.clone();
		return o;
	}
	

}