WikiEventListener extends Java's EventListener, defining an interface for an object that listens for WikiEvent. Unlike most Java event handling, there's no need for class-level maintenance of listener lists (e.g., add and remove listener methods), since this is all handled by methods within the WikiEventManager.
WikiEventListener is part of the JSPWiki WikiEvent package.
One can simultaneously create an anonymous class implementing the WikiEventListener interface and using the WikiEventManager add it as a listener for events from a given object (often this, the source object):
WikiEventManager.addWikiEventListener(this, new WikiEventListener() { public void actionPerformed( WikiEvent e ) { if ( e.getSource() instanceof SomeObject && e.getType() == SOME_TYPE ) { // do something intelligent here } } });How you react to events, i.e., what you do within actionPerformed() is up to you, but typically there'll first be a test for the type of source object and the event type.