策略模式

模式定义：

定义了算法族，分别封装起来，让它们之间可以互相替换，此模式的变化独立于算法的使用者。

image-20230423142656652

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public class StrategyTest {
    public static void main(String[] args) {
        Context context = new Context(new GreenPen());
        context.executeDraw(10,0,0);
    }
}

interface Strategy{
    public int draw(int radius, int x, int y );
}

class RedPen implements Strategy{

    @Override
    public int draw(int radius, int x, int y) {
        System.out.println("使用红笔画画.");
        return radius;
    }
}

class GreenPen implements Strategy{

    @Override
    public int draw(int radius, int x, int y) {
        System.out.println("使用绿笔画画.");
        return radius;
    }
}

class Context{
    private Strategy strategy;

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

    public int executeDraw(int radius, int x, int y) {
        return strategy.draw(radius,x,y);
    }
}

image-20230423143811170