策略模式-三十六计

策略模式属于对象的行为模式。其用意是针对一组算法，将每一个算法封装到具有共同接口的独立类中。从而使它们可以互相替换。策略模式使得算法可以在不影响客户端的情况下发生变化。

策略模式用法1

在一场战争中，一个伟大的将领需要根据敌人的数量，巧妙的使用各种计谋，来获取战争的胜利。将不同的计谋封装到单独的Stratagem类中，每个计谋有他们可以战胜的敌人个数。战争Warfare开始之前，将领需要根据自己对战场形势的判断，传入不同的计谋。

package strategy_k;/*
* @auther 顶风少年 
* @mail [email protected]
* @date 2020-01-18 12:55
* @notify 
* @version 1.0
*/
public interface Stratagem {
    void killEnemy();
}

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package strategy_k;/*
* @auther 顶风少年 
* @mail [email protected]
* @date 2020-01-18 12:57
* @notify 
* @version 1.0
*/
public class OneStratagem implements Stratagem{

    @Override
    public void killEnemy() {
        System.out.println("杀敌100");
    }
}

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package strategy_k;/*
* @auther 顶风少年 
* @mail [email protected]
* @date 2020-01-18 12:57
* @notify 
* @version 1.0
*/
public class TwoStratagem implements Stratagem{

    @Override
    public void killEnemy() {
        System.out.println("杀敌200");
    }
}

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package strategy_k;/*
 * @auther 顶风少年
 * @mail [email protected]
 * @date 2020-01-18 12:57
 * @notify
 * @version 1.0
 */

public class ThreeStratagem implements Stratagem {

    @Override
    public void killEnemy() {
        System.out.println("杀敌300");
    }
}

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package strategy_k;/*
 * @auther 顶风少年
 * @mail [email protected]
 * @date 2020-01-18 13:00
 * @notify
 * @version 1.0
 */

public class Warfare {
    private Stratagem stratagem;

    public Warfare(Stratagem stratagem) {
        this.stratagem = stratagem;
    }

    public void start() {
        stratagem.killEnemy();
    }
}

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package strategy_k;/*
* @auther 顶风少年 
* @mail [email protected]
* @date 2020-01-18 13:01
* @notify 
* @version 1.0
*/
public class Main {
    public static void main(String[] args) {
        Warfare warfare = new Warfare(new OneStratagem());
        warfare.start();
    }
}

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策略模式用法2

兵书中的计谋太多了，如果对阵的是100人，将领选择杀敌300人的计谋固然可以完全取胜，但是造成的兵马消耗也是巨大的。于是兵书的编纂者，给每一个计谋扩展了一个方法，计算当前计谋能否战胜敌人。如果可以战胜，自动的选择该计谋。

package strategy_k;/*
* @auther 顶风少年 
* @mail [email protected]
* @date 2020-01-18 12:55
* @notify 
* @version 1.0
*/
public interface Stratagem {
    void killEnemy();
    boolean compare(int kill);
}

View Code

package strategy_k;/*
 * @auther 顶风少年
 * @mail [email protected]
 * @date 2020-01-18 12:57
 * @notify
 * @version 1.0
 */

public class OneStratagem implements Stratagem {

    @Override
    public void killEnemy() {
        System.out.println("杀敌100");
    }

    @Override
    public boolean compare(int kill) {
        if (kill <= 100) {
            return true;
        }
        return false;
    }


}

View Code

package strategy_k;/*
* @auther 顶风少年 
* @mail [email protected]
* @date 2020-01-18 12:57
* @notify 
* @version 1.0
*/
public class TwoStratagem implements Stratagem{

    @Override
    public void killEnemy() {
        System.out.println("杀敌200");
    }

    @Override
    public boolean compare(int kill) {
        if (kill <= 200) {
            return true;
        }
        return false;
    }
}

View Code

package strategy_k;/*
 * @auther 顶风少年
 * @mail [email protected]
 * @date 2020-01-18 12:57
 * @notify
 * @version 1.0
 */

public class ThreeStratagem implements Stratagem {

    @Override
    public void killEnemy() {
        System.out.println("杀敌300");
    }

    @Override
    public boolean compare(int kill) {
        if (kill <= 300) {
            return true;
        }
        return false;
    }
}

View Code

package strategy_k;/*
 * @auther 顶风少年
 * @mail [email protected]
 * @date 2020-01-18 13:00
 * @notify
 * @version 1.0
 */

import java.util.ArrayList;
import java.util.List;

public class Warfare {
    private List<Stratagem> stratagemList = new ArrayList<>();

    public Warfare(List<Stratagem> stratagemList) {
        this.stratagemList = stratagemList;
    }

    public void start() {
        Stratagem stratagem = null;
        for (Stratagem s : stratagemList) {
            boolean compare = s.compare(200);
            if (compare) {
                stratagem = s;
                break;
            }
        }
        stratagem.killEnemy();
    }
}

View Code

package strategy_k;/*
* @auther 顶风少年 
* @mail [email protected]
* @date 2020-01-18 13:01
* @notify 
* @version 1.0
*/

import java.util.ArrayList;

public class Main {
    public static void main(String[] args) {
        ArrayList<Stratagem> stratagems = new ArrayList<>();
        stratagems.add(new OneStratagem());
        stratagems.add(new TwoStratagem());
        stratagems.add(new ThreeStratagem());

        Warfare warfare = new Warfare(stratagems);
        warfare.start();
    }
}

View Code