REVERT TO CONSOLE

It’s insanely easy to write an interceptor in EJB3. Here’s a tutorial/example code for an interceptor which collects statistics info around a method invocation.

import java.util.Collection;
import javax.interceptor.AroundInvoke;
import javax.interceptor.InvocationContext;
import org.apache.commons.lang.time.StopWatch;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

public class StatisticsInterceptor {
	private static final Log log = LogFactory
			.getLog(StatisticsInterceptor.class);

	@AroundInvoke
	@SuppressWarnings("unchecked")
	public Object intercept(InvocationContext ctx) throws Exception {
		StopWatch stopWatch = new StopWatch();
		stopWatch.start();
		Object result = ctx.proceed();
		log.debug("Statistics for "
				+ ctx.getMethod().getDeclaringClass().getSimpleName() + "."
				+ ctx.getMethod().getName());
		log.debug("\tTime = " + stopWatch);
		if (result instanceof String) {
			log.debug("\tValue returned = " + result);
		}
		if (result instanceof Collection) {
			Collection col = (Collection) result;
			log.debug("\tSize of collection returned = " + col.size());
		}
		return result;
	}
}

The only place, this needs to be added is in ejb-jar.xml

<assembly-descriptor>
      <interceptor-binding>
         <ejb-name>*</ejb-name>
         <interceptor-class>org.jboss.seam.ejb.SeamInterceptor</interceptor-class>
      </interceptor-binding>
      <interceptor-binding>
         <ejb-name>*</ejb-name>
         <interceptor-class>com.evergreen.asr.util.StatisticsInterceptor</interceptor-class>
      </interceptor-binding>
   </assembly-descriptor>

That’s it.