设计模式----策略模式

策略模式定义了一系列的算法，并将每一个算法封装起来，而且使它们还可以相互替换。策略模式让算法独立于使用它的客户而独立变化。（原文：The Strategy Pattern defines a family of algorithms,encapsulates each one,and makes them interchangeable. Strategy lets the algorithm vary independently from clients that use it.）

 

实例

算法接口：Strategy.java

package strategy;

public interface Strategy {
	public void AlgorithmInterface();
}

 

具体算法A实现：ConcreteStrategyA.java

package strategy;

public class ConcreteStrategyA implements Strategy {

	@Override
	public void AlgorithmInterface() {
		// TODO Auto-generated method stub
		System.out.println("具体算法A实现");
	}

}

 

具体算法B实现：ConcreteStrategyB.java

package strategy;

public class ConcreteStrategyB implements Strategy {

	@Override
	public void AlgorithmInterface() {
		// TODO Auto-generated method stub
		System.out.println("具体算法B实现");
	}

}

 

上下文类，维护一个对Strategy对象的引用：Context.java

package strategy;

public class Context {
	
	public Context(Strategy strategy) {	//初始化时，传入具体的策略对象
		this.strategy = strategy;
	}
	
	public void contextInterface() {
		strategy.AlgorithmInterface();
	}
	
	private Strategy strategy;
}

 

Main函数：Main.java

package strategy;

public class Main {

	/**
	 * @param args
	 */
	public static void main(String[] args) {
		// TODO Auto-generated method stub
		Context context;
		
		//算法A
		context = new Context(new ConcreteStrategyA());
		context.contextInterface();
		//算法B
		context = new Context(new ConcreteStrategyB());
		context.contextInterface();
	}

}