aop链式调用

ゝ一世哀愁。 2023-06-04 10:00 29阅读 0赞

--------------------

多个aop如果叠加  
采用了责任链的模式

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzM4NTQyMDg1_size_16_color_FFFFFF_t_70]

使用ConcerteHandler实现类实现HandleProcess接口同时这个实现类又组合了这个接口，通过successor判断来进行链式调用

--------------------

首先我们新建一个Handler

public abstract class Handler { 
    
        private Handler successor;
    
        public Handler getSuccessor() { 
            return successor;
        }
    
        public void setSuccessor(Handler successor) { 
            this.successor = successor;
        }
    
        public void execute(){ 
            handleProcess();
            if(successor != null){ 
                successor.execute();
            }
        }
    
        protected abstract void handleProcess();
    }

--------------------

下面我们看看client端实现

public class ChainClient { 
        static class HandlerA extends Handler{ 
    
            @Override
            protected void handleProcess() { 
                System.out.println("handler by a");
            }
        }
    
        static class HandlerB extends Handler{ 
    
            @Override
            protected void handleProcess() { 
                System.out.println("handler by b");
            }
        }
    
        static class HandlerC extends Handler{ 
    
            @Override
            protected void handleProcess() { 
                System.out.println("handler by c");
            }
        }
    
        public static void main(String[] args) { 
            Handler handlerA = new HandlerA();
            Handler handlerB = new HandlerB();
            Handler handlerC = new HandlerC();
            handlerA.setSuccessor(handlerB);
            handlerB.setSuccessor(handlerC);
            handlerA.execute();
        }
    }

由此我们实现了链式调用，但是我们也发现了每次都需要设置从属关系。

--------------------

下面我们对上面方法改造，使用另外一个Chain对再下面的代码进行一次封装

public static void main(String[] args) { 
        Handler handlerA = new HandlerA();
        Handler handlerB = new HandlerB();
        Handler handlerC = new HandlerC();
        handlerA.setSuccessor(handlerB);
        handlerB.setSuccessor(handlerC);
        handlerA.execute();
    }

--------------------

下面我们新建一个ChainHandler

public abstract class ChainHandler { 
    
        public void execute(Chain chain){ 
            handleProcess();
            chain.proceed();
        }
        protected abstract void handleProcess();
    }

--------------------

Chain对链式关系封装起来

public class Chain { 
        private List<ChainHandler> handlers;
    
        private int index = 0;
    
        public Chain(List<ChainHandler> handlers) { 
            this.handlers = handlers;
        }
        public void proceed(){ 
            if(index >= handlers.size()){ 
                return;
            }
            handlers.get(index++).execute(this);
        }
    }

--------------------

下面我们看一下如何实现调用类

public class ChainClient { 
        static class ChainHandlerA extends ChainHandler{ 
            @Override
            protected void handleProcess() { 
                System.out.println("handler by chain a");
            }
        }
        static class ChainHandlerB extends ChainHandler{ 
            @Override
            protected void handleProcess() { 
                System.out.println("handler by chain b");
            }
        }
        static class ChainHandlerC extends ChainHandler{ 
            @Override
            protected void handleProcess() { 
                System.out.println("handler by chain c");
            }
        }
        public static void main(String[] args) { 
            List<ChainHandler> handlers = Arrays.asList(
                    new ChainHandlerA(),
                    new ChainHandlerB(),
                    new ChainHandlerC()
            );
            Chain chain = new Chain(handlers);
            chain.proceed();
        }
    }

[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzM4NTQyMDg1_size_16_color_FFFFFF_t_70]: /images/20230601/9b9c5590fd5c4642839311a19a318a2f.png