设计模式之策略模式

/**
 * @author yuyang
 * @DATE 2019/1/7 0007-9:12
 * 抽象策略角色
 */
public interface Strategy {
    int calc(int a,int b);
}

/**
 * @author yuyang
 * @DATE 2019/1/7 0007-9:12
 *具体策略模式
 */
public class Addcalc implements Strategy {
    @Override
    public int calc(int a,int b) {
        return a+b;
    }
}

/**
 * @author yuyang
 * @DATE 2019/1/7 0007-9:14
   具体策略角色
 */
public class Subtractcalc implements Strategy{
    @Override
    public int calc(int a, int b) {
        return a-b;
    }
}

/**
 * @author yuyang
 * @DATE 2019/1/7 0007-9:15
   环境角色
 */
public class Environment {
    Strategy strategy;

    public Environment(Strategy strategy) {
        this.strategy = strategy;
    }

    public int calc(int a,int b){
        return strategy.calc(a,b);
    }
}

/**
 * @author yuyang
 * @DATE 2019/1/7 0007-9:14

 */
public class Text {
    public static void main(String[] args) {

        Environment environment = new Environment(new Subtractcalc());
        System.out.println(environment.calc(5,5));

    }
}