Re: [aspectj-users] Static crosscutting

["Ron Bodkin" <rbodkin@xxxxxxxxxxxxxx>]

Eric,

All you need to do is to add those methods to your interface too. E.g.,

public interface BeanSupport {
  void addPropertyChangeListener(PropertyChangeListener listener);
  void removePropertyChangeListener(PropertyChangeListener listener);
  void firePropertyChange(String name, Object original, Object modified);
}

with your same aspect as posted still providing the inter-type declarations to implement them. The interface acts a bit like a .h file and the inter-type decl implementation like a .C (I know, scary analogy).

Ron Bodkin
Chief Technology Officer
New Aspects of Security
m: (415) 509-2895

> ------------Original Message-------------
> From: "Eric Jain" <Eric.Jain@xxxxxxxxxx>
> To: "aspectj-users" <aspectj-users@xxxxxxxxxxx>
> Date: Sat, Sep-27-2003 9:15 AM
> Subject: Re: [aspectj-users] Static crosscutting
> 
> > For a reusable version of bean support, please look at
> > a solution that I posted to a JavaRanch forum:
> >
> >
> http://saloon.javaranch.com/cgi-bin/ubb/ultimatebb.cgi?ubb=get_topic&f=14&t=000304
> 
> 
> Thanks. I had a look at your code and implemented a similar solution,
> which unfortunately doesn't quite work. One of my requirements is that
> the interface that allows addition of listeners must be useable from
> editors that are not aspect-aware. Therefore, after adding the
> possibility to register change listeners to a class called Taxon, I
> can't require developers to write:
> 
>   taxon.addPropertyChangeListener(...);
> 
> because this would only compile with ajc. Or this:
> 
>   taxon.ajc$...$pcs.addPropertyChangeListener(...);
> 
> not only because it is way too ugly, but it would also fail if the
> imported library happens to not be postprocessed. On the other hand
> everybody could do this:
> 
>   if (object instanceof BeanSupport)
>     ((BeanSupport) taxon).addPropertyChangeListener(...);
> 
> Any suggestions how to accomplish this? Here is my approach, which works
> except that after applying it I get a compile time error ("The method
> addPropertyChangeListener is undefined for the type BeanSupport"). The
> BeanSupport interface is a normal interface that declares methods such
> as addPropertyChangeListener.
> 
> package org.expasy.aspects;
> 
> import java.beans.PropertyChangeEvent;
> import java.beans.PropertyChangeListener;
> import java.beans.PropertyChangeSupport;
> import org.expasy.models.util.BeanSupport;
> import org.expasy.models.taxonomy.Taxon;
> 
> public aspect PropertyChange
> {
>   declare parents: Taxon implements BeanSupport;
> 
>   private PropertyChangeSupport BeanSupport.pcs =
>     new PropertyChangeSupport(this);
> 
>   pointcut setter(BeanSupport source, Object value):
>     execution(void BeanSupport+.set*(*))
>       && target(source) && args(value);
> 
>   after(BeanSupport source, Object value): setter(source, value)
>   {
>     String property = thisJoinPointStaticPart.getSignature()
>       .getName().substring(3).toLowerCase();
>     source.firePropertyChange(property, null, value);
>  }
> 
>   public void
> BeanSupport.addPropertyChangeListener(PropertyChangeListener listener)
>   {
>     pcs.addPropertyChangeListener(listener);
>   }
> 
>   public void
> BeanSupport.removePropertyChangeListener(PropertyChangeListener
> listener)
>   {
>     pcs.removePropertyChangeListener(listener);
>   }
> 
>   public void BeanSupport.firePropertyChange(String name, Object
> original, Object modified)
>   {
>     pcs.firePropertyChange(name, original, modified);
>   }
> }
> 
> 
> --
> Eric Jain
> 
> 
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