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.

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

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());