Name: mc57594 Date: 07/27/99


I believe that firePropertyChange in PropertyChangeSupport has a
problem. Currently, the code looks like this:

 public void firePropertyChange(String propertyName,
     Object oldValue, Object newValue) {

 if (oldValue != null && oldValue.equals(newValue)) {
     return;
 }
etc.

I understand section 7.4.4 of the spec. The problem with this
implementation of it arises in a situation where I have a deep
graph of beans. Suppose that an object, A, is listening to a
complex property, P1, of another object, B. Within A, there is
another listener, C, to a property of property P1. B fires P1,
but the new instance of P1 is .equals equal to the old value of
P1, so it doesn't fire. The result is that C is listening to
the completely wrong object!

For this to work with both complex object graphs and primitives,
I propose the following change:

 public void firePropertyChange(String propertyName,
     Object oldValue, Object newValue) {

 if (oldValue != null && oldValue == newValue) {
     return;
 }
etc.

In most situations, this will continue to work as it currently
does. In some cases, however, .equals will return true
while == will return false. It is my assertion that the
property change event should fire under these conditions, and
the code change above will allow the event to fire.

Thanks in advance for your consideration of this bug.
(Review ID: 57491)
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