1 Reply Latest reply on Nov 20, 2010 1:13 AM by rick.dong

FieldWriteInvocation.getValue does not reflecting changes made along interceptors

rick.dong Nov 19, 2010 8:11 PM

I have two field write interceptors A and B that is instrumented on a particular fileld. A gets invoked before B. Can someone please confirm whether the following should work?

class A implements Interceptor
{
     public final Object invoke(Invocation invocation) throws Throwable 
     {
          if (invocation instanceof FieldWriteInvocation)
          {
               FieldWriteInvocation fwi = (FieldWriteInvocation)invocation;

               Integer value = fwi.getValue(); //value here is 1 suppose

               fwi.setValue(2); //change the value          
          }

          return invocation.invokeNext();
     }
}

after A is done, B is invoked

{code:java}
class B implements Interceptor
{
     public final Object invoke(Invocation invocation) throws Throwable
     {
          if (invocation instanceof FieldWriteInvocation)
          {
               FieldWriteInvocation fwi = (FieldWriteInvocation)invocation;
               Integer value = fwi.getValue(); //value here should've been 2, but still is 1 (bug??)
          }
          return invocation.invokeNext();
     }
}{code}

I was trying to change the final value that gets set to a field by using the interceptors, but it seems never works. Also setting a breakpoint

at getValue() seems never gets triggered. I've created an issue @ https://jira.jboss.org/browse/JBAOP-802.

Thanks,

1. Re: FieldWriteInvocation.getValue does not reflecting changes made along interceptors

rick.dong Nov 20, 2010 1:13 AM (in response to rick.dong)

digging into the code, it seems that this could be a bug

private static class WriteBaseClassGenerator extends BaseClassGenerator
   {
      private static final String GET_VALUE = "getValue";
      private static final String SET_VALUE = "setValue";

     ....

      protected CtClass setupClass()throws NotFoundException, CannotCompileException
      {
         CtClass setUp = super.setupClass();
         CtField valueField = new CtField(getArgumentType(), TYPED_VALUE_FIELD, setUp);
         jp.addField(valueField);
         CtMethod oldGetValue = WRITE_INVOCATION_CT_TYPE.getDeclaredMethod(GET_VALUE);
         CtMethod getValue = CtNewMethod.make(oldGetValue.getReturnType(),
               GET_VALUE, oldGetValue.getParameterTypes(),
               oldGetValue.getExceptionTypes(), "{return ($w)" + TYPED_VALUE_FIELD + ";}",
               setUp);
         setUp.addMethod(getValue);
         CtMethod oldSetValue = WRITE_INVOCATION_CT_TYPE.getDeclaredMethod(SET_VALUE);
         CtMethod setValue = CtNewMethod.make(oldSetValue.getReturnType(),
               GET_VALUE, oldSetValue.getParameterTypes(),
               oldSetValue.getExceptionTypes(), "{" + TYPED_VALUE_FIELD + " = " +
               JavassistToReflect.castInvocationValueToTypeString(getArgumentType(),
                     "$1") + ";}", setUp);
         setUp.addMethod(setValue);
         return setUp;
      }

Shouldn't the bolded part be SET_VALUE instead for the set to take effect?

Message was edited by: Rick Dong
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