AOP Asynchronous Method Invocation

This aspect can run outside of JBoss application server

It was tested using JDK 1.4 in Weblogic 8.1,Tomcat 5.0.27 ,Orion 2.0.2 and Resin 3.0.4.

Goal

The aim of this AOP service is to achieve asynchronous method invocation to plain old JAVA object (POJO).

Features

• Implemented as a standalone service (can run outside of JBOSS).

• Ability to define Asynchronous method declaration in XML or using JDK1.5 annotations.

• Support ONEWAY and REQUEST/REPLY asynchronous method invocation.

• Support of instance and static asynchronous method invocation.

• Support of public, protected, private and package method.

• Support of concurrent invocation on same instance/static method.

• Ability to define Timeout value for duration of asynchronous method execution.

• Thread pooling Management (Min/Max threads, keep-alive, abort/wait policy)

Usage

POJO implementation using JDK1.4 or JDK1.5 annotations for Asynchronous method declaration. For JDK 1.4 you need the AnnotationCompiler

JDK 1.4

public class POJO {

/** @@org.jboss.aspects.asynchronous.aspects.jboss.Asynchronous  */
     public void processBusinessModel(){...}

/** @@org.jboss.aspects.asynchronous.aspects.jboss.Asynchronous */ 
     public long processBusinessModel(...){}
 
}

JDK 5.0

import org.jboss.aspects.asynchronous.aspects.jboss.Asynchronous;

public class POJO {
     public void processBusinessModel(){...}

        @Asynchronous
     public long processBusinessModel(...){}
 
}

Asynchronous Method Invocation and result process within same thread of execution

POJO pojo = new POJO(...);

/ Asynchronous Method Invocation /

long result=pojo.processBusinessModel(...);
...
...

/ non-blocking call /

if (((AsynchronousFacade)pojo).isDone())
{
AsynchronousFacade aF=(AsynchronousFacade)pojo;

/ Test response code returned /

if (aF.getResponseCode()==OK)

/ get method response processed asynchronously /

result = ((Long)aF.getReturnValue()).longValue();

/ Test if method timed out /

else if (aF.getResponseCode()==TIMEOUT)
{...}
else
... 
}

else {

/ blocking call /

AsynchronousResponse aR = ((AsynchronousFacade)pojo).waitForResponse();
If (aR.getResponseCode()==OK)

/ get method response processed asynchronously /

result=((Long)aR.getReturnValue()).longValue();

/ Test if method timed out /

else if (aR.getReponseCode()==TIMEOUT)
{...}
else
{...}
}

Configuration

If not running within JBoss, you'll need a binding like this:

• If using JBoss AOP AOP 1.3.4 (see JBOSS-AOP.xml):

<?xml version="1.0" encoding="UTF-8"?>
<aop>
  <aspect class="org.jboss.aspects.asynchronous.aspects.jboss.AsynchronousAspect" scope="PER_VM"></aspect>
   
  <bind pointcut="execution(* *->@org.jboss.aspects.asynchronous.aspects.jboss.Asynchronous(..))">
     <advice name="execute" aspect="org.jboss.aspects.asynchronous.aspects.jboss.AsynchronousAspect"></advice>
  </bind>                                                                                
<introduction expr="has(* *->@org.jboss.aspects.asynchronous.aspects.jboss.Asynchronous(..)) OR class(@org.jboss.aspects.asynchronous.aspects.jboss.Asynchronous)">
     <mixin>
        <interfaces>org.jboss.aspects.asynchronous.aspects.AsynchronousFacade</interfaces>
        <class>org.jboss.aspects.asynchronous.aspects.AsynchronousFacadeImpl</class>
        <construction>new org.jboss.aspects.asynchronous.aspects.AsynchronousFacadeImpl()</construction>
     </mixin>
  </introduction>  
</aop>

• If running JBoss AOP 1.5.0.GA or above:

<?xml version="1.0" encoding="UTF-8"?>
<aop>
   <aspect class="org.jboss.aspects.asynch.AsynchAspect" scope="PER_INSTANCE">
      <advisor-attribute name="Advisor"></advisor-attribute>
   </aspect>

   <bind pointcut="execution(!static * *->@org.jboss.aspects.asynch.Asynchronous(..))">
      <advice name="execute" aspect="org.jboss.aspects.asynch.AsynchAspect"></advice>
   </bind>

   <introduction expr="has(!static * *->@org.jboss.aspects.asynch.Asynchronous(..))">
      <mixin>
         <interfaces>org.jboss.aspects.asynch.AsynchProvider,org.jboss.aspects.asynch.FutureHolder</interfaces>
         <class>org.jboss.aspects.asynch.AsynchMixin</class>
      </mixin>
   </introduction>
</aop>

Set up

Before building the final deployable archive, an instrumentation (aopc) phase is required using the binding in previous section so that pojos that might have @Asynchronous annotation are instrumented. You can further information on different options to instrument classes in the the AOP documentation

Example

Please find attached a Asynchronous pojo example which contains a README file explaining the example including how to deploy it and run it.

Note: To run the attached example, JBoss AS/EAP 4.2 or higher is required.

Implementation

Few pointers regarding the implementation .

The implementation is broken down in 4 components :

• Asynchronous Engine Definition

  /org/jboss/aspects/asynchronous

  /org/jboss/aspects/asynchronous/common

• Asynchronous Engine Implementation with the concurrent package

  /org/jboss/aspects/asynchronous/concurrent

• Asynchronous Facade Definition and Implementation (Mixin Class)

  /org/jboss/aspects/asynchronous/aspects

• Asynchronous Aspect Implementation with JBOSS-AOP

  /org/jboss/aspects/asynchronus/aspects/jboss

  The Asynchronous Aspect is composed of one Mixin class (AsynchronousFacade.java)

and one method interceptor.(AsynchronousAspect.java)

Author

• Claude Hussenet (mailto:chussenet@yahoo.com)