Re: [aspectj-users] trying to write a simple caching aspect

[Bo Yi <boyi@xxxxxxxxxx>]

Ideally, I would think the following pointcut:

pointcut callingCachable() : call (ICachable+.new(..)); // calling any
constructor that implements ICachable interface

and advice:

advice Object around() : callingCachable() {
      Object object = getCached(getTarget().getClassName());
      if (object == null) {
           object =  proceed();
           addToCache(object);
      }
      return object;
}

But according to syntax of pointcut, ICachable+ is not acceptable syntax. I
would like to see such syntax extension (not only for constructors, but for
methods). Not sure it is feasible. Any one have any thought?

Thanks,

Bo
----------------------------------------------------------
  Dr. Bo Yi
  WAS L3 Support
  IBM Toronto Lab
  A2-713/Q2Z/8200/MKM
  8200 Warden Ave. Markham ONT. L6G 1C7
  Phone: 905-413-4819
  Tie Line: 969-4819
  E-Mail: boyi@xxxxxxxxxx



                                                                       
             "Jody Brownell"                                           
             <jody.brownell@Q1                                         
             Labs.com>                                                  To
             Sent by:                  <aspectj-users@xxxxxxxxxxx>     
             aspectj-users-adm                                          cc
             in@xxxxxxxxxxx                                            
                                                                   Subject
                                       [aspectj-users] trying to write a
             10/21/2004 12:18          simple caching aspect           
             PM                                                        
                                                                       
                                                                       
             Please respond to                                         
               aspectj-users                                           
                                                                       
                                                                       




Hi ? I am new to aspectj, I am working through some example and trying to
develop a few aspects as a proof of concept.
The first aspect I am trying to develop is a real simple caching aspect
which caches objects based on the implementation of a tag interface.

What I would like to do is when a constructor is called, check if the class
implements an interface, if it does check the cache. If there is
no reference in the cache, proceed, cache the object and then return it.
Otherwise return the cached instance.

What I need to be able to do is get the name of the class the constructor
is being called on. My pointcut should really select all
constructors in the system (maybe confined to a package) with any number of
arguments. Once I have the class object or the name,
I can determine if the cache should be consulted.

Is this possible? If so could someone provide me with an example of the
pointcut and advice.  I would provide what I have already but I
am stumped as to how I can capture class of the object I am trying to
instantiate. My problem is I would like to capture the class as context in
an around advice using a target() like construct.


Thanks in advance.
Jody b.