1 Reply Latest reply on Jan 26, 2005 2:22 AM by Kabir Khan

    Constructor Aspects ignored when using a Factory Pattern

    Paul Extance Newbie

      I'm using "JBoss (MX MicroKernel) [4.0.1 (build: CVSTag=JBoss_4_0_1 date=200501141152)]", and the version of JBoss AOP that comes as part of that deployment.

      I have created some pointcuts that attached methods to the constructor, for example

      <prepare expr="execution(public org.jaffa.applications.jaffa.modules.admin.components.usermaintenance.ui.*->new(..))"/>


      I have enabled runtime aspect injection via the setting < attribute name ="EnableTransformer" >true< /attribute >

      Everything works fine, the interceptors are correctly bound to the methods, but i have a problem with interceptors not being invoked for the constructor. I believe this is because I use a Factory pattern for constructing new instance of my object via the clazz.newInstance().

      If I hard code the new Class() constructor, JBoss will replace it with the correct call to an injected public static method to invoke the constructor interceptors and create the object.

      Can I therefore assume that to use JBoss AOP on constructors all object factories must be re-written to call this new public static method, if the class being constructed implements the Advised interface?

      Original Factory Code...
       Component compInst = (Component) clazz.newInstance();
      

      New Factory Code to be JBoss AOP complient...
       Component compInst = null;
       // Use the Advised static method to create the object if needed.
       if(clazz instanceof Advised) {
       String name = clazz.getName().substring(clazz.getName().lastIndexOf('.')) + "_new_$aop";
       Method method = clazz.getDeclaredMethods(name, new Class[0]);
       compInst = method.invoke(null, new Object[0]);
       }
       if(compInst==null)
       compInst = clazz.newInstance();
      

      Am I missing something here, as this seems very intrusive, expecially if i now need to go and modify the likes of Struts so i can bind aspects to the creation of a FormBean?

      I'm sure you must address similar issues in Hibernate when creating new objects that may have constructor interceptor stacks?

      Please advise....

      PaulE
      (http://jaffa.sf.net)