策略模式结合简单工厂模式

package Stragery;

public abstract class Operation {

public abstract int oper(int a);

}

各自的算法实现：

　　　

package Stragery;

public class OperationImpl extends Operation {



public int oper(int a)

{

System.out.println("使用算法1");



return a;

}





}

class OperationImplB extends Operation {



public int oper(int a)

{

System.out.println("使用算法2");



return a+2;

}





}

class OperationImplC extends Operation {



public int oper(int a)

{

System.out.println("使用算法3");



return a+3;

}





}

　策略类：



public class StrageryContext {

Operation oper=null;

public StrageryContext(int no)

{

switch (no)

{



case 1:

OperationImpl os=new OperationImpl();

oper=os;

break;



case 2:

OperationImplB os1=new OperationImplB();

oper=os1;

break;



case 3:

OperationImplC os2=new OperationImplC();

oper=os2;

break;



}







}



public int getResult(int a)

{

return oper.oper(a);

}



}

Client使用类：

　　public class Client {



public static void main(String args[]){

StrageryContext context;



int a;

System.out.println("演示调用算法1");



context=new StrageryContext(new Integer(1));



a=12;

context.getResult(a);





System.out.println("演示调用算法2");



context=new StrageryContext(new Integer(2));





context.getResult(a);





System.out.println("演示调用算法3");



context=new StrageryContext(new Integer(3));



a=12;

context.getResult(a);











}

}