Apply Dynamic Proxy to all the classes in an application

Question

I want to apply the Dynamic Proxy I created to all the classes that are part of my application. But, I also want to be able to use dependency injection (Spring) instead of writing something like MyDynamicProxy.newInstance(new Account());

Where newInstance is:

public static Object newInstance(Object object) {             
return Proxy.newProxyInstance(object.getClass().getClassLoader(),object.getClass().getInterfaces(),new LoggingProxy(object));        
}

How can I apply Dependency Injection and Dynamic Proxy to all the classes in my application?

score 1 · Answer 1 · answered May 04 '11 at 09:07

1

You could try using org.springframework.beans.factory.config.BeanPostProcessor.postProcessAfterInitialization(Object, String) and returning your proxy instance instead of the original bean.

NB if it's just logging you're after, it might be simpler to look into using Spring's AOP support which will allow you to define a simple logging aspect on all Spring managed beans.

answered May 04 '11 at 09:07

artbristol

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+1 for BeanPostProcessor. Although I wouldn't advise it, it's nice to know there's more than one way to do it – Sean Patrick Floyd May 04 '11 at 09:16

Sean Patrick Floyd · Answer 2 · 2011-05-04T09:41:46.430

Don't create your proxies manually, use Spring AOP to create your Logging Proxy.

Create a simple Aspect:

@Aspect
public class LoggingAspect{

    private static final Logger log = Logger.getLogger(LoggingAspect.class);

    @Pointcut("execution(* *.*(..))")
    public void methodExecution(){
    }

    @Before("methodExecution()")
    public void logBeforeMethod(final JoinPoint joinPoint){
        log.trace("Entering method " + joinPoint.getSignature() + " with args "
            + Arrays.toString(joinPoint.getArgs()));
    }

}

Now wire the aspect in Spring:

<beans xmlns="http://www.springframework.org/schema/beans"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xmlns:aop="http://www.springframework.org/schema/aop"
    xsi:schemaLocation="http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-3.0.xsd
        http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.0.xsd">


    <bean class="aspects.LoggingAspect" />
    <aop:aspectj-autoproxy />

</beans>

Now all your Spring Beans will be proxies and all of their method executions (at leaast those backed by an interface) will be logged.

BTW: Tracing Aspects are covered in the free Chapter 10 of AspectJ in Action by Ramnivas Laddad

Apply Dynamic Proxy to all the classes in an application

2 Answers2