Generic interceptor with dependancy injection

[rsw]

I am trying to create an interceptor class that uses a @EJB tag to inject a site specific implementation of an interface. This is a common use case for our product where each site has specific code that is executed based on a trigger (method invocation). I am simply modifing the EJBTrail example trying to make this work. The following code compiles cleanly, deploys cleanly, yet throw an execption on execution.

/*** Interceptor base class *****/
package trail.interceptor;

import javax.annotation.EJB;
import javax.ejb.AroundInvoke;
import javax.ejb.InvocationContext;


public class BasicIntercept {

 // Inject EJB
 @EJB
 CalcTwoNumbers calc2;

 @AroundInvoke
 public Object trigger (InvocationContext ctx)
 throws Exception {
 return(calc2.doIt(ctx));
 }

}

/**** implementation interface ********/
package trail.interceptor;

import javax.ejb.InvocationContext;


public interface CalcTwoNumbers {

 public Object doIt (InvocationContext ctx)
 throws Exception;

}

/***** simple example implementation ****/
package trail.interceptor;

import javax.annotation.EJB;
import javax.ejb.*;



@Stateless
public class CalcTwoNumbersMulti implements CalcTwoNumbers {


 public Object doIt (InvocationContext ctx)
 throws Exception {
 int x = 3;
 int y = 2;
 CalculatorBean cal = (CalculatorBean) ctx.getBean();
 String className = ctx.getBean().getClass().getName();
 String methodName = ctx.getMethod().getName();


 cal.setTrace("Intercepted call to "+ className + "." + methodName +
 "!\nCalcTwoNumber x=" + x + " y=" + y +
 " result = " + (x * y) );
 try {
 return ctx.proceed();
 } catch(Exception e) {
 throw e;
 } finally {
 System.out.println("CalcTwoNumber x=" + x + " y=" + y +
 " result = " + (x * y) );

 }

 }

}

/*** setup interceptor ***/
package trail.interceptor;

import javax.ejb.*;
import java.util.*;
import java.io.Serializable;

//TODO: Fix the client
@Stateful
@Interceptor(BasicIntercept.class)
public class CalculatorBean implements Calculator, Serializable {
......

According to the examples this should work and I cannot find anything in the EJB3.0 spec that forbids this type of design. But here is the exception:

javax.ejb.EJBException: null; CausedByException is:
 null
 org.jboss.ejb3.tx.Ejb3TxPolicy.handleExceptionInOurTx(Ejb3TxPolicy.java:46)
 org.jboss.aspects.tx.TxPolicy.invokeInOurTx(TxPolicy.java:70)
 org.jboss.aspects.tx.TxInterceptor$Required.invoke(TxInterceptor.java:134)
 org.jboss.aop.joinpoint.MethodInvocation.invokeNext(MethodInvocation.java:88)
 org.jboss.aspects.tx.TxPropagationInterceptor.invoke(TxPropagationInterceptor.java:72)
 org.jboss.aop.joinpoint.MethodInvocation.invokeNext(MethodInvocation.java:88)
 org.jboss.aspects.security.AuthenticationInterceptor.invoke(AuthenticationInterceptor.java:63)
 org.jboss.aop.joinpoint.MethodInvocation.invokeNext(MethodInvocation.java:88)
 org.jboss.ejb3.asynchronous.AsynchronousInterceptor.invoke(AsynchronousInterceptor.java:93)
 org.jboss.aop.joinpoint.MethodInvocation.invokeNext(MethodInvocation.java:88)
 org.jboss.ejb3.stateful.StatefulContainer.localInvoke(StatefulContainer.java:122)
 org.jboss.ejb3.stateful.StatefulLocalProxy.invoke(StatefulLocalProxy.java:86)
 $Proxy87.setTrace(Unknown Source)
 org.apache.jsp.services.interceptor.calculator_jsp._jspService(org.apache.jsp.services.interceptor.calculator_jsp:80)
 org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:97)
 javax.servlet.http.HttpServlet.service(HttpServlet.java:810)
 org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:322)
 org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:314)
 org.apache.jasper.servlet.JspServlet.service(JspServlet.java:264)
 javax.servlet.http.HttpServlet.service(HttpServlet.java:810)
 org.jboss.web.tomcat.filters.ReplyHeaderFilter.doFilter(ReplyHeaderFilter.java:81)

Any help would be appreciated.

Randy