An abstract wrapper class for anEventListener class which associates a set of additional parameters with the listener. Subclasses must provide the storage and accessor methods for the additional arguments or parameters.

For example, a bean which supports named properties would have a two argument method signature for adding aPropertyChangeListener for a property:

 public void addPropertyChangeListener(String propertyName,                                       PropertyChangeListener listener)

If the bean also implemented the zero argument get listener method:

 public PropertyChangeListener[] getPropertyChangeListeners()

then the array may contain innerPropertyChangeListeners which are alsoPropertyChangeListenerProxy objects.

If the calling method is interested in retrieving the named property then it would have to test the element to see if it is a proxy class.