Re: [aspectj-users] Can I do any of these 3 things with aspectJ

["Tarun Sharma" <t_sharma@xxxxxxxxxxxx>]

I am quite surprised, that there is not even a single reply to the mail
below, I send earlier =(. Is this out of discussion.?


On Thu, 04 Sep 2003 13:10:00 -0800, "Tarun Sharma"
<t_sharma@xxxxxxxxxxxx> said:
> Hi Guys
> 
> I have 3 questions and would be great if you have any comments or
> suggestions on these.
> 
> Question 1 : If, my requirement is to return a different instance (say
> instantiating overloaded constructor) of an object whose default
> constructor is called. Can I do that with aspectJ. The limitation is that
> I do not want to use call() pointcut, (as this needs the caller's to be
> included in weaving though source or binary and I do not have control
> over the usages of my framework).
> 
> Question 2 : If we use inter-type declaration's for let us say adding
> method's to existing classes, what I understood that you cannot define
> methods for more than one class in one decleration. For example (1) is
> what is possible, IS (2) possible to achieve somehow.? I do not want to
> define the same behaviour for every class. I want every class for a
> package to get this method added with same behaviour. To achieve this
> kind of result, I also tried private interface, but landed in a problem
> again which is question 3. 
> 
> (1)----   public int Point.getX() { return this.x; }
> 
> (2) --    public int com.x.y.*.getX() { return this.x; }
> 
> Question 3 : When I tried a private interface, I had a problem again: The
> problem is "this" which is explicitly available in the method definition
> of the private interface, does seem have limitations. The code I was
> trying is below (for simplicity this is the main purpose of code). The
> probelm is that, I am using reflection to set instance field
> WHICH_IS_PRIVATE and you can only do that from the same class using
> "this"(as far as I am aware of), so i thought the below solution might
> work.? But it didn't, as the weaving is not done as-is but rather through
> references (Obviously I had to de-compile to figure out what's
> happening), may be in most cases the waeving works but not in this case
> or I am doing something wrong:
> 
> 	private interface MyInterface {}
> 
> 	declare parents: com.x.y.MyComponent implements MyInterface ;
> 
> 	public pointcut populate(java.lang.Object o) : execution(*.new()) && this(o) && within(com.x.y.MyComponent);
> 
> 	public void MyInterface.setMember(Object memberValue){
> 		/**
> 		Using reflection I got the field object of, one of instance field
> 		defined in MyComponent class.And I try to set this with the memberValue
> 		argument using the field.set(this,memberValue)
> 		**/
> 
> 		Field field = SomeService.getField();								
> 
> 		    try{
> 			field.set(this,memberValue);
> 		    } catch (IllegalArgumentException e) {
> 		    e.printStackTrace();
> 		    } catch (IllegalAccessException e) {
> 		    e.printStackTrace();
> 		    }
> 		}
> 
> 	    }
> 
> 	after (java.lang.Object o) : populate(o) {	
> 		MyInterface myInterfaceAwareObject = (MyInterface)o;
> 		myInterfaceAwareObject.setMember($some_value);
> 	}
> 
> I would really appreciate any comments on these issues or suggestions.
> 
> Thanks in advance
> Tarun
> 
> -- 
>   Tarun Sharma
>   t_sharma@xxxxxxxxxxxx
> 
> -- 
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-- 
  Tarun Sharma
  t_sharma@xxxxxxxxxxxx

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