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Re: [aspectj-users] Parameters

Works for me in AspectJ 1.0; see below.

For Gregor's case "foo(Type, Type)", the compiler issues
an error message about incompatible bindings.

Wes

----- output
 src $ aspectj-1.0 -d classes -classpath $ajrt Args.java
 src $ j4 -classpath "classes;$ajrt" Args
call(void Args.one(String)): Hello, World!
execution(void Args.one(String)): Hello, World!
call(void Args.first(String, int, long)): Hello, World!
execution(void Args.first(String, int, long)): Hello, World!
call(void Args.middle(int, String, long)): Hello, World!
execution(void Args.middle(int, String, long)): Hello, World!
call(void Args.last(int, long, String)): Hello, World!
execution(void Args.last(int, long, String)): Hello, World!
call(void java.io.PrintStream.println(String)): Hello, World!
Hello, World!

----- Args.java

public class Args {
    public static void main(String[] a) {
        one("Hello, World!");
    }
    static void none() {
        throw new Error("here");
    }
    static void one(String s) {
        first(s, 0, 0l);
    }
    static void first(String s, int i, long j) {
        middle(i, s, j);
    }
    static void middle(int i, String s, long j) {
        last(i, j, s);
    }
    static void last(int i, long j, String s) {
        System.out.println(s);
    }
    // would get compiler error here
//    static void last(String s, String t) {
//        System.out.println(s);
//    }
}
aspect A {
    before(String s) : !within(A) && args(..,s,..) {
        System.out.println(thisJoinPointStaticPart + ": " + s);
    }
}

DiFrango, Ron wrote:
Wes,

Thanks for your answer and it does not work in 1.0 as that is the version I
am on currently.  Actually it was what I expected.  I am surprised that I am
one of the first to bring this up.

I personally would like to see the ability to use multiple wildcards in a
PCD.  The main driver for me is that I am retrofitting old code and I would
prefer to keep the pre-existing interfaces as much intact as possible.

Should I submit a bug report on this?

Thanks,

Ron DiFrango


-----Original Message-----
From: Wes Isberg [mailto:wes@xxxxxxxxxxxxxx] Sent: Wednesday, August 20, 2003 12:03 AM
To: aspectj-users@xxxxxxxxxxx
Subject: Re: [aspectj-users] Parameters


   args(.., ClassX, ..)

should have worked in AspectJ 1.0, but, as Erik noted for 1.1,

   We did not implement the handling of more than one ..
   wildcard in args PCDs (rarely encountered in the wild)
   because we didn't have the time. This might be available
   in later releases if there is significant outcry
http://dev.eclipse.org/viewcvs/indextech.cgi/~checkout~/aspectj-home/doc/REA
DME-11.html#language

I'm not sure if a bug would qualify as a significant outcry, but it would be
a place others could chime in.

(Also, it's a doc bug that ".." in args(...) is not better documented. I
couldn't find it in either quick reference or the programming guide
semantics appendix; perhaps my search was bad.)

A workaround for now is to test the args directly, perhaps even in an if
pointcut:

aspect A {
    private static boolean hasArg(Class c, Object[] args) {
         for (int i = 0; i < args.length; i++) {
            if ((null != args[i]) &&
               c.isAssignableFrom(args[i].getClass())) {
               return true;
            }
         }
         return false;
    }
    before() : ... && if(hasArg(ClassX.class, thisJoinPoint.getArgs()) {
        ...
    }
}

Obviously, that won't pick out a null ClassX arg, and it
can be expensive, depending on the rest of your pointcut.

Wes


DiFrango, Ron wrote:


All,

I could not find an answer to this in any of the old postings. I have methods that take a common parameter. The problem is that depending on the method call this parameter may be listed anywhere in the method signature. So for example:

	public class ParametersInMethodCalls
	{
		public void example1(ClassX x, double I, String s)
		{
		}

		public void example2(int I, ClassX x, double d)
		{
		}

		public void example2(float I, String s, ClassX x)
		{
		}
	}

My question is can I define a pointcuts that picks out all the above combinations without having to "code if you will" the different permutations possible? I have tried the following examples/permutations:

pointcut examples(ClassX x) : execution(public * ParametersInMethodCalls.*(..))
		&& args(.., x);

	==> Afected example2

pointcut examples(ClassX x) : execution(public * ParametersInMethodCalls.*(..))
		&& args(x, ..);

	==> Afected example1

pointcut examples(ClassX x) : execution(public * ParametersInMethodCalls.*(..))
		&& args(*, x);

	==> Affect nothing

The important thing to note is that all the methods I want to pick out have the common input of ClassX, but there is an indeterminate number of other parameters to these methods. Furthermore, I would prefer to avoid having to change the underlying code as it affects a large body of code.

Thanks in advance,

Ron DiFrango

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**************************************************************************
The information transmitted herewith is sensitive information intended only
for use by the individual or entity to which it is addressed. If the reader
of this message is not the intended recipient, you are hereby notified that
any review, retransmission, dissemination, distribution, copying or other
use of, or taking of any action in reliance upon this information is
strictly prohibited. If you have received this communication in error,
please contact the sender and delete the material from your computer.
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