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Re: [aspectj-users] Newbie Questions: Biggest Issue
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> I wasn't able to find any
> explanation of the exact syntax of the "after returning" statement and I
> thought "target()" must refer to what the method was returning. I didn't
> realize you specified that differently, as per your code. The proper syntax
> and what each parameter in that syntax means is documented somewhere, right?
I actually went to where I thought it should be in the docs and it
wasn't explained there! So it is a hole in the docs, if you have time
please raise a bugzilla so we fix it at some point.
cheers,
Andy
On 24 February 2012 16:23, Rhino <rhino1@xxxxxxxxxxxx> wrote:
> Thank you VERY much for clearing that up, Andy! NOW I can stop spinning my
> wheels and get on with learning AspectJ!
>
> Given that the code in the example I was imitating didn't have any
> corresponding source code for the Java classes, I made an educated guess on
> what it was doing and obviously guessed wrong. I wasn't able to find any
> explanation of the exact syntax of the "after returning" statement and I
> thought "target()" must refer to what the method was returning. I didn't
> realize you specified that differently, as per your code. The proper syntax
> and what each parameter in that syntax means is documented somewhere, right?
> Preferably with examples so that I can be really clear exactly what is meant
> by each part of each statement....
>
> --
> Rhino
>
>
> On 2012-02-24 18:13, Andy Clement wrote:
>>
>> Hi,
>>>
>>> after(int num, String needle, String haystack) returning:
>>> target(num)
>>> && args(needle, haystack)
>>> && call(* Test01.count(..)) {
>>>
>>> System.out.println("** needle = " + needle + "; haystack = " +
>>> haystack + "; num = " + num); //$NON-NLS-1$
>>> }
>>
>> Your problem is target(num). The target pointcut captures the target
>> of the method invocation (so in this case the instance of Test01 on
>> which count is running). Test01 is not an int so your target()
>> doesn't match. If you want to capture the return value of a call, you
>> want this:
>>
>> after(String needle, String haystack) returning(int num):
>> args(needle,haystack)&& call(* Test01.count(..));
>>
>>
>> cheers,
>> Andy.
>>
>>
>> On 24 February 2012 14:17, Rhino<rhino1@xxxxxxxxxxxx> wrote:
>>>
>>> Greetings!
>>>
>>> I'm just beginning with AspectJ today so I hope you can all forgive a
>>> newbie
>>> with some questions. I'll ask them in sequential emails to keep the size
>>> of
>>> each question manageable....
>>>
>>> While the idea behind AspectJ seems worthwhile and I'm already starting
>>> to
>>> get a sense of the potential, I'm getting bogged down in beginner issues.
>>>
>>> The biggest problem I'm having is that I can't access values from one of
>>> my
>>> methods.
>>>
>>> I'm trying to imitate this example from the AspectJ Language Guide in my
>>> own
>>> code:
>>>
>>> after(FigureElement fe, int x, int y) returning:
>>> call(void FigureElement.setXY(int, int))
>>> && target(fe)
>>> && args(x, y) {
>>> System.out.println(fe + " moved to (" + x + ", " + y + ")");
>>> }
>>>
>>> This is my play program:
>>>
>>> ============================================
>>> package test;
>>>
>>> import ca.maximal.common.utilities.CountUtils;
>>>
>>> public class Test01 {
>>>
>>> final String CLASS_NAME = getClass().getName();
>>>
>>> public static void main(String[] args) {
>>>
>>> @SuppressWarnings("unused")
>>> Test01 countStuff = new Test01();
>>> }
>>>
>>> public Test01() {
>>>
>>> String needle = "a";
>>> String haystack = "supercalifragilisticexpialadocious";
>>> int occurrences = count(needle, haystack);
>>> System.out.println("needle = " + needle + "; haystack = " +
>>> haystack
>>> + "; count = " + occurrences);
>>> }
>>>
>>> private static int count(String needle, String haystack) {
>>>
>>> int count = CountUtils.count(needle, haystack);
>>>
>>> return count;
>>> }
>>> }
>>> ============================================
>>>
>>> This is my Aspect:
>>>
>>> ============================================
>>> package test;
>>>
>>>
>>> /**
>>> * This class
>>> *
>>> *<p>More</p>
>>> *
>>> * @version 1.0
>>> * @since Feb 24, 2012
>>> */
>>> public aspect LogCount {
>>>
>>> pointcut howManyNeedles() : execution(* Test01.count(..));
>>>
>>> // pointcut count2() : call(int count(String, String));
>>>
>>> /* First Before */
>>> before() : howManyNeedles() {
>>> System.out.println("About to count...."); //$NON-NLS-1$
>>> }
>>>
>>> /* First After */
>>> after() returning() : howManyNeedles() {
>>> System.out.println("...Needles counted"); //$NON-NLS-1$
>>> }
>>>
>>> /* Second After */
>>> after(int num, String needle, String haystack) returning:
>>> target(num)
>>> && args(needle, haystack)
>>> && call(* Test01.count(..)) {
>>>
>>> System.out.println("** needle = " + needle + "; haystack = " +
>>> haystack + "; num = " + num); //$NON-NLS-1$
>>> }
>>>
>>> }
>>> ============================================
>>>
>>> The "First Before" and "First After" pointcuts work fine. But the "Second
>>> After" resolutely refuses to work despite many different variations on
>>> the
>>> call() statement. I've tried everything I can think of but NOTHING works.
>>>
>>> I'm sure this is something very simple but I'm darned if I can figure it
>>> out. I wonder if someone on this mailing list can help me see what's
>>> wrong?
>>>
>>> --
>>> Rhino
>>> _______________________________________________
>>> aspectj-users mailing list
>>> aspectj-users@xxxxxxxxxxx
>>> https://dev.eclipse.org/mailman/listinfo/aspectj-users
>>
>> _______________________________________________
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>>
>>
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