AspectJ JoinPoint question

Question

I am currently using JoinPoint to capture the parameters passed to service methods at runtime. Though JoinPoint helps me retrieve the parameter values, I see that it doesn't provide any good API to retrieve the names of the parameters, parameter types, individual parameter values when the parameter passed is an array etc.

Here's an example:

public void doIt(String user, Attribute[] attr, Integer[] i, boolean bool, List<Attribute> list){.....}

For the above method, when I use JoinPoint.getArgs(), i see a garbage value for the parameter which is an array or a collection. If the parameter is an array or a collection, how can I verify if they are one of those and how can I traverse them to retrieve individual values?

Any suggestions ? Thanks

Biju Kunjummen · Answer 1 · 2011-04-20T13:40:03.080

23

This should work:

MethodSignature signature = (MethodSignature)joinPoint.getSignature();
String[] parameterNames = signature.getParameterNames();
Object[] parameterValues = joinPoint.getArgs();

The parameterNames should match what you have passed in.

Update 1: You are probably compiling with debugging symbols turned off -(explicitly passing in javac -g:none, or through flags in maven/ant). With debugging symbols off, names will not be available and will replaced with args1 etc by the compiler. Try with a compilation with debug symbols not explicitly turned off.

edited Apr 20 '11 at 13:40

answered Apr 20 '11 at 01:54

Biju Kunjummen

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Helo, This doesn't seem to work. It returns arg0 arg1 arg2 arg3 arg4 etc. – soontobeared Apr 20 '11 at 13:01
I have updated my answer, you probably have debug symbols turned off. Try without explicitly turning off debug symbols, the parameter names should then be correctly retrieved. – Biju Kunjummen Apr 20 '11 at 13:40
@Biju Do you have an idea how to turn the debug symbols in maven ? – Modi May 21 '14 at 10:11
Hi @MordechaiTamam, using the compiler maven plugin, the debug is on by default - http://maven.apache.org/plugins/maven-compiler-plugin/compile-mojo.html, you can control it quite a bit more through the debuglevel flag also mentioned in the doc – Biju Kunjummen May 21 '14 at 11:51

score 2 · Answer 2 · answered Apr 11 '14 at 04:49

AspectJ pointcut

public pointcut pointcutName():
        execution(* ClassName.method(..));

Getting Parameter names of the method

before():pointcutName(){
String[] paramNames = ((CodeSignature) thisJoinPointStaticPart
                .getSignature()).getParameterNames();
 for(String paramName:paramNames){
            System.out.println(paramName);
        }
}

Getting Parameter Values:

before():pointcutName(){
Object[] paramValues = thisJoinPoint.getArgs();

for (Object object:paramValues){
        System.out.println(object.toString);
        }
}

Getting Method Return Value:

after() returning(Object objectReturn) :pointcutName(){
    System.out.println(objectReturn);
}

AspectJ JoinPoint question

2 Answers2

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