java责任链模式

模仿OKhhtp的责任链模式

1)首先两个接口

public interface Interceptors {
    int intercept(Chain chain) ;
    interface Chain{
        int proceed();
    }
}

2)接口实现类

//第一个接口实现类 我们模拟到最后一个类才返回真正的数据
public class MyInterceptors implements Interceptors {
    @Override
    public int intercept(Interceptors.Chain chain) {
     //这里可做一些业务 构建
        return chain.proceed();
    }

    public static class MyInterceptorsa implements Interceptors {
        @Override
        public int intercept(Chain chain) {
            return chain.proceed();
        }
    }

    public static class MyInterceptorsb implements Interceptors {
        @Override
        public int intercept(Chain chain) {
            return chain.proceed();
        }
    }

    public static class MyInterceptorsc implements Interceptors {
        @Override
        public int intercept(Chain chain) {
            return chain.proceed();
        }
    }

    public static class MyInterceptorsd implements Interceptors {
        @Override
        public int intercept(Chain chain) {
            return chain.proceed();
        }
    }

    public static class MyInterceptorse implements Interceptors {
        @Override
        public int intercept(Chain chain) {
            return 5;
        }
    }
}

//这个是核心类
    public class RealInterceptorChain implements Interceptors.Chain {
        List<Interceptors> interceptors;
        final int index;
        @Override
        public int proceed() {
            System.out.println("====index===" + index);
            if (index >= interceptors.size()) {
                return -10000;
            } else {
                RealInterceptorChain next = new RealInterceptorChain(interceptors, index + 1);
                Interceptors interceptor = interceptors.get(index);
                int response = interceptor.intercept(next);
                return response;
            }


        }


        public RealInterceptorChain(List<Interceptors> interceptors, int index) {
            this.interceptors = interceptors;
            this.index = index;
        }

    }

3)测试

 public static void main(String[] args) {
        ArrayList<Interceptors> interceptors = new ArrayList<>();
        interceptors.add(new MyInterceptors());
        interceptors.add(new MyInterceptors.MyInterceptorsa());
        interceptors.add(new MyInterceptors.MyInterceptorsb());
        interceptors.add(new MyInterceptors.MyInterceptorsc());
        interceptors.add(new MyInterceptors.MyInterceptorsd());
        interceptors.add(new MyInterceptors.MyInterceptorse());
        RealInterceptorChain mRealInterceptorChain = new RealInterceptorChain(interceptors, 0);
        System.out.println("====a == b  >>>>>" + mRealInterceptorChain.proceed());
    }

打印出结果 
====index===0
====index===1
====index===2
====index===3
====index===4
====index===5
====a == b  >>>>>5