设计模式1--策略模式（the strategy design pattern）

冷不防 2024-02-17 16:11 39阅读 0赞

策略模式，在不同事物（抽象类）之间发现共同点，将共同点汇集进一个单独的接口中(interface)，将不同点放入到接口的实现中（有几个不同就有几个实现）。在生成不同事物的对象时，将接口的实现实例化，作为参数传给不同的事物。这里说的事物不是Transaction。

doTask() \{\}

doTask() \{Overriding code\}  
doTask() \{More overriding code\}  
  
  
Your Code

Algorithm variable

<--------Algorithm object 1

<--------Algorithm object 2  
<--------Algorithm object 3

public interface GoAlgorithm
    {
    	public void go();
    }
    
    public abstract class Vehicle
    {
    	private GoAlgorithm goAlogrithm; // algorithm variable
    	
    	public Vehicle(){}
    	
    	public void setGoAlgorithm(GoAlgorithm algorithm)
    	{
    		goAlogrithm = algorithm;
    	}
    	
    	public void go() {
    		goAlogrithm.go();
    	}
    }
    
    /**
    * algorithm object 1
    **/
    public class GoByDrivingAlgorithm implements GoAlgorithm
    {
    	public void go()
    	{
    		System.out.println("Now Im driving");
    	}
    }
    
    /**
    * algorithm object 2
    **/
    public class GoByFlyingAlgorithm implements GoAlgorithm
    {
    	public void go()
    	{
    		System.out.println("Now Im flying");
    	}
    }
    
    /**
    * algorithm object 3
    **/
    public class GoByFlyingFast implements GoAlgorithm
    {
    	public void go()
    	{
    		System.out.println("Now Im flying fast");
    	}
    }
    
    
    public class StreetRacer extends Vehicle
    {
    	public StreetRacer()
    	{
    		setGoAlgorithm (new GoByDrivingAlgorithm());
    	}
    }
    
    public class Helicopter extends Vehicle
    {
    	public Helicopter() {
    		setGoAlgorithm(new GoByFlyingAlgorithm());
    	}
    }
    
    public class Jet extends Vehicle
    {
    	public Jet() {
    		setGoAlgorithm(new GoByFlyingFast());
    	}
    }
    
    
    public static void main(String args[]) 
    {
    	StreetRacer streetRacer = new StreetRacer();
    	streetRacer.go();
    	Helicopter helicopter = new Helicopter();
    	helicopter.go();
    	Jet jet = new Jet();
    	jet.go();
    }