What are my options if I want to proxy all service calls so that I can log them appropriately without an explicit call to a logger?

Instead of trying to get developers to remember to log each service method call and/or exception, is there a pattern that will proxy to t开发者_如何学Gohe right service method, in the process logging the call, and trapping/logging any exceptions that are thrown before returning a response back to the caller? I know there is a proxy pattern, but I'm not sure it does what I need it to... if there is a way to create an interface that will better enforce a logging requirement, then I'm open to that as well.

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Logging is a cross cutting concern. You can use AOP for that. Have a look at AspectJ or Spring AOP.

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You could consider using Dynamic proxies for implementing your service layer.

It uses the reflection api so all method calls to your service code will go through a single "invoke" method where you can log service calls, method parameters and exception messages.

public class MyServiceProxy implements InvocationHandler {
            public static Object newInstance(Object obj) {
                    return java.lang.reflect.Proxy.newProxyInstance(
        obj.getClass().getClassLoader(),
        obj.getClass().getInterfaces(),
        new MyServiceProxy(obj));
        }

             public Object invoke(Object proxy, Method m, Object[] args) {
                   // Log method name , parameters etc.
                   try {
                       method.invoke(proxy, args) ;
                   }
                   catch(InvocationTargetException e) {
                      // log your exceptions and do other things
                      throw e.getTargetException();
                   }
             }

Where you call your service, you would instead do this

          MyService myServiceRef = (MyService)MyServiceProxy.newInstance(new MyService());