Hi Mohammad,
mmm ... the decompiled bytecode seems correct : it creates a joinpoint
static part, then executes the previous static initializer (which is empty),
and then calls the after advice both when an exception is raised and when no
exception is raised.
Bytecode, AFAIK, cannot be commented out, is that the output of javap, dj or
which other tool?
Obviously, static initializer is executed only when the class is loaded for
the first time in the JVM, if it is not loaded it will not be called and the
class not be registered. Java lacks a serious "service discovery" system,
cause for backward compatibility with applets classloaders does not have a
method for "listing" the classpath, not to mention to list which classes are
annotated with a specific annotations. Apt is the tool that can ease this
pain, creating a text file from classes annotated with a specific
annotation, but unfortunately it works at compile time, not at runtime,
that's why there is still the need for files like persistence.xml in JPA and
web.xml in jars.
To make a long story short, as Andy did in his code, somewhere you must
still call "new ClassUnderObservation()" or at least
Class.forName("com.foo.ClassUnderObservation") or access a static field or
method of that class to get it loaded by the jvm, otherwise no static init,
no registration in the aspect.
Simone
2010/4/28 Andy Clement <[email protected]>
> You didn't mention how it fails?? Here is Simones code in a real
> program, appears to work. What is different about your code or that
> particular type? Perhaps narrow your pointcut to a specific type to
> test the registration logic is working before expanding it to cover
> more types?
>
> === A.aj ===
> package com.foo;
>
> import java.lang.annotation.Retention;
> import java.lang.annotation.RetentionPolicy;
> import java.util.*;
>
> import org.aspectj.lang.reflect.InitializerSignature;
>
> @Retention(RetentionPolicy.RUNTIME)
> @interface Observer {}
>
> aspect A {
> public static void main(String[] args) {
> new C();new D(); new E();
> }
>
> static List<Class> registry = new ArrayList<Class>();
>
> pointcut observerKlasses(): staticinitialization(@Observer com..*);
>
> after(): observerKlasses() {
> InitializerSignature initsig =
> (InitializerSignature)thisJoinPointStaticPart.getSignature();
> Class klass = initsig.getDeclaringType();
> registry.add(klass);
> System.out.println("Registering "+klass);
> }
>
> }
>
> @Observer
> class C {}
>
> class D{}
>
> @Observer
> class E {}
> ===
> ajc A.aj
> java A
> Registering class com.foo.C
> Registering class com.foo.E
>
> cheers,
> Andy
>
> On 28 April 2010 00:30, Mohammad Norouzi <[email protected]> wrote:
> > Hi Simone,
> > Thanks... I did what you said but there is a problem. During the compile
> > there is no error but it seems the static block doesn't work. I tried to
> > decompile the target class to see what changes AspectJ has applied and I
> can
> > see a static block has been created but it is commented as follow:
> >
> >
> > // ERROR //
> > static
> > {
> > // Byte code:
> > // 0: new 87 org/aspectj/runtime/reflect/Factory
> > // 3: dup
> > // 4: ldc 88
> > // 6: ldc 90
> > // 8: invokestatic 96 java/lang/Class:forName
> > (Ljava/lang/String;)Ljava/lang/Class;
> > // 11: invokespecial 99
> > org/aspectj/runtime/reflect/Factory:<init>
> > (Ljava/lang/String;Ljava/lang/Class;)V
> > // 14: astore_0
> > // 15: aload_0
> > // 16: ldc 101
> > // 18: aload_0
> > // 19: ldc 103
> > // 21: ldc 90
> > // 23: invokevirtual 107
> > org/aspectj/runtime/reflect/Factory:makeInitializerSig
> >
> (Ljava/lang/String;Ljava/lang/String;)Lorg/aspectj/lang/reflect/InitializerSignature;
> > // 26: iconst_0
> > // 27: invokevirtual 111
> > org/aspectj/runtime/reflect/Factory:makeSJP
> >
> (Ljava/lang/String;Lorg/aspectj/lang/Signature;I)Lorg/aspectj/lang/JoinPoint$StaticPart;
> > // 30: putstatic 79 com/foo/listener/MyListener1:ajc$tjp_0
> > Lorg/aspectj/lang/JoinPoint$StaticPart;
> > // 33: goto +28 -> 61
> > // 36: astore_0
> > // 37: aload_0
> > // 38: instanceof 71
> > // 41: ifeq +8 -> 49
> > // 44: aload_0
> > // 45: checkcast 71 java/lang/ExceptionInInitializerError
> > // 48: athrow
> > // 49: nop
> > // 50: invokestatic 77
> > com/foo/aspect/EventDispatcherAspect:aspectOf
> > ()Lcom/foo/aspect/EventDispatcherAspect;
> > // 53: getstatic 79 com/foo/listener/MyListener1:ajc$tjp_0
> > Lorg/aspectj/lang/JoinPoint$StaticPart;
> > // 56: invokevirtual 83
> >
> com/foo/aspect/EventDispatcherAspect:ajc$after$com_foo_aspect_EventDispatcherAspect$1$5b3bc9fd
> > (Lorg/aspectj/lang/JoinPoint$StaticPart;)V
> > // 59: aload_0
> > // 60: athrow
> > // 61: invokestatic 77
> > com/foo/aspect/EventDispatcherAspect:aspectOf
> > ()Lcom/foo/aspect/EventDispatcherAspect;
> > // 64: getstatic 79 com/foo/listener/MyListener1:ajc$tjp_0
> > Lorg/aspectj/lang/JoinPoint$StaticPart;
> > // 67: invokevirtual 83
> >
> com/foo/aspect/EventDispatcherAspect:ajc$after$com_foo_aspect_EventDispatcherAspect$1$5b3bc9fd
> > (Lorg/aspectj/lang/JoinPoint$StaticPart;)V
> > // 70: return
> > //
> > // Exception table:
> > // from to target type
> > // 33 36 36 java/lang/Throwable
> > }
> >
> > Regards,
> > Mohammad
> > --------------------------
> > Sun Certified Web Developer
> > ExpertsExchange Certified, Master:
> > http://www.experts-exchange.com/M_1938796.html
> > Have a look at some pictures @ http://pixelshot.wordpress.com/
> > Do you like to read, see http://brainable.blogspot.com/
> > For the Persians see http://fekre-motefavet.blogspot.com/
> > English
> > Forum:
> http://n2.nabble.com/English-Phrase-Finder-For-Persians-f3274251.html
> >
> >
> >
> >
> > On Tue, Apr 27, 2010 at 7:33 PM, Simone Gianni <[email protected]>
> wrote:
> >>
> >> Hi Mohammad,
> >> staticinitialization has no target object because when a class is
> >> initialized there is no instance yet. Probably you can obtain the class
> and
> >> other informations using ThisJoinPointStaticPart inside your advice.
> >>
> >> pointcut observerMethods():
> >> staticinitialization(@Observer com..*);
> >>
> >> after(): observerMethods() {
> >> InitializerSignature initsig =
> >> (InitializerSignature)ThisJoinPointStaticPart.getSignature();
> >> Class klass = initsig.getDeclaringType();
> >> // adding 'klass' into Registry
> >> }
> >>
> >> See http://www.eclipse.org/aspectj/doc/released/runtime-api/index.htmlfor
> >> more info.
> >>
> >> Simone
> >>
> >> 2010/4/27 Mohammad Norouzi <[email protected]>
> >>>
> >>> Hello
> >>> I want to register those classes annotated with @Observer in a Registry
> >>> class... I want this occurs in a static block of such classes:
> >>>
> >>> pointcut observerMethods(Class klass):
> >>> staticinitialization(@Observer com..*)
> >>> && target(klass);
> >>>
> >>> after(Class klass): observerMethods(klass) {
> >>> // adding 'klass' into Registry
> >>>
> >>> }
> >>>
> >>> but as I read in manual it is said staticinitialization has no target
> >>> object... is this right? if yes, how can I obtain the Class of those
> >>> classes. Can I declare a static-block for matching classes?
> >>>
> >>> thanks
> >>>
> >>> Regards,
> >>> Mohammad
> >>> --------------------------
> >>> Sun Certified Web Developer
> >>> Have a look at some pictures @ http://pixelshot.wordpress.com/
> >>>
> >>>
> >>>
> >>> _______________________________________________
> >>> aspectj-users mailing list
> >>> [email protected]
> >>> https://dev.eclipse.org/mailman/listinfo/aspectj-users
> >>>
> >>
> >>
> >> _______________________________________________
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> >>
> >
> >
> > _______________________________________________
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> >
> >
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