Hi Josh:

Brian Rapalje's project at URL:

http://www.ccs.neu.edu/research/demeter/course/f97/projects/java-beans1

on the interoperability aspect (Java Beans) is ready for integration with Demeter/Java. Our DARPA
work requires such an interoperability solution. Besides *.beh, *.cd, *.cool and *.ridl files we will 
also have *.beanspec files. An example is below: from X.cd, X.beh, X.beanspec, we generate XBean.
asp and XBeanInfo.java.

For viewing start with file project.html.

(there is also a second project by Mike Miller:
http://www.ccs.neu.edu/research/demeter/course/f97/projects/java-beans2
on the same topic. We need to integrate the two.)

The interoperability aspect has a different flavor than the structure aspect: it is more localized. The
X.beanspec information goes into class X and class XBeanInfo only and is not spread throughout
the program like the structural information. But it is still an aspect, although a less systemic one.
Another difference to the structure aspect is that beanspec information is not duplicated several times
into the target program. It is used once.

Brian mentions several features which need to be added. He could not express certain changes with
your weaver notation. Does it need an addition?

I would like you to give a presentation on Java Beans for Demeter/Java
in the second week of January. Please can you prepare for that? 
Suggested outline:

0. Overview of Java Beans.
1.  Demonstration of Brian's project: Linking two Demeter/Java generated          beans (using a 
2.  version of Brian's netscape files on my labtop).
2. Interoperability aspect language.
3. Translation to aspect file and BeanInfo file.
4. What needs to be improved?
5. Are their interaction problems with other aspects?

-- Karl

Example:

X.beanspec:
package test1;

X {
  Method : inc
  Property : ReadOnly text
  Property : Bound ReadWrite n
}

X.cd:
package test2;

X = <text> String <n> Integer.

X.beh:
X {
  init (@
    n = new Integer(0);
    text = "Hello World";
  @)

  public void inc() (@ 
    set_n(new Integer(n.intValue()+1));
  @)
}

generates:

XBean.asp
core:

import java.beans.*;
import java.io.*;

implement: java.io.Serializable in: X;

add: to: X {
 PropertyChangeSupport _pcs = (@ new PropertyChangeSupport(this) @)
}

add: to: X {
 public void addPropertyChangeListener(PropertyChangeListener l) (@
  _pcs.addPropertyChangeListener(l);
 @)
}

add: to: X {
 public void removePropertyChangeListener(PropertyChangeListener l) (@
  _pcs.removePropertyChangeListener(l);
 @)
}

before: X.set_n (@
 Object _old = n;
@)

after: X.set_n (@
 _pcs.firePropertyChange("n", _old, new_n);
@)

and

XBeanInfo.java
package test1;

import java.beans.*;
import java.lang.*;
import java.lang.reflect.*;
import java.util.*;

public class XBeanInfo extends SimpleBeanInfo {
  final static Class beanClass = X.class;
  PropertyDescriptor properties[] = new PropertyDescriptor[2];
  EventSetDescriptor eventSet[] = new EventSetDescriptor[1];
  MethodDescriptor methods[] = null; // new MethodDescriptor[1];
  public XBeanInfo() {
    try {
      properties[0] = new PropertyDescriptor("text",
        beanClass,
        "get_text",
        "set_text");
      properties[1] = new PropertyDescriptor("n",
        beanClass,
        "get_n",
        "set_n");
    String listenerMethods[] = {"propertyChange"};
    eventSet[0] = new EventSetDescriptor(beanClass,
                        "propertyChange",
                        PropertyChangeListener.class,
                        listenerMethods,
                        "addPropertyChangeListener",
                        "removePropertyChangeListener");
    } catch (Exception e) { e.printStackTrace(); }
  }
  public PropertyDescriptor[] getPropertyDescriptors() { return properties; }
  public int getDefaultPropertyIndex() { return -1; }
  public MethodDescriptor[] getMethodDescriptors() { return methods; }
  public EventSetDescriptor[] getEventSetDescriptors() { return eventSet; }
  public int getDefaultEventIndex() { return -1; }
  public BeanDescriptor getBeanDescriptor() { return new BeanDescriptor(beanClass); }
  public BeanInfo[] getAdditionalBeanInfo() { return null; }
  public java.awt.Image getIcon(int iconKind) { return null; }
}