[aspectj-users] Re: [NEWSDELIVER] Cannot get the inserted element for Co

[Matthew Webster <matthew_webster@xxxxxxxxxx>]

SunnyDay,

The get() pointcut allows you to intercept
field references. In you example this will happen before the object is
added. If you want to advise the program immediately after an object is
added to a Collection then you should use something like this:

public aspect Aspect {
        pointcut
fieldGet() : get(* *);

        pointcut
addObject (Collection field) : 
         
      call(public * add(Object)) && target(field);

        
//        after()
returning(Object field): fieldGet() {
        after(Object
field) returning : addObject(field) {
         
        if (field instanceof Collection)
         
        {
         
               
               
Collection collField = (Collection)field;
         
               
               
Iterator it = collField.iterator();
         
               
               
while (it.hasNext())
         
               
               
{
         
               
               
                 System.out.println("after
" + it.next());
         
               
               
}
         
        }
         
               
               
                 
        }
}

Matthew Webster
AOSD Project
Java Technology Centre, MP146
IBM Hursley Park, Winchester,  SO21 2JN, England
Telephone: +44 196 2816139 (external) 246139 (internal) 
Email: Matthew Webster/UK/IBM @ IBMGB, matthew_webster@xxxxxxxxxx
http://w3.hursley.ibm.com/~websterm/

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cc:        
Subject:        [NEWSDELIVER] Cannot get the inserted element for Collection field



Hi,

I am trying to get the new contents for a field of Collection type, such
as java.util.Vector, after an element is added or deleted each time. Here
is what I did:

pointcut fieldGet() : get(* *);

after() returning(Object field): fieldGet() {
         if (field instanceof Collection)
         {
                                 Collection collField = (Collection)field;
                                 Iterator it = collField.iterator();
                                 while (it.hasNext())
                                 {
                                                  System.out.println("after " + it.next());
                                 }
         }
                                                 
}

Matched code:

public class A
{
                Vector v = new Vector();
                public void addB()
                {
                                 v.add(new B());
                                 // v.add(new B());
                }
}

I had expected to get object B's reference after the first v.add(new B());
but there is nothing returned from the collection. But if I add another
v.add(new B());, I can only see one B's instance from the collection. How
may I get the most up-to-date contents of the Vector v after it is
accessed? Thanks very much for any help!

SunnyDay