Defines events and listener interfaces for Tapestry.

{@link org.apache.tapestry.event.ChangeObserver} and {@link org.apache.tapestry.event.ObservedChangeEvent} are used to communicate changes in persistent properties from pages and components to page recorders.

The remaining interfaces {@link org.apache.tapestry.event.PageDetachListener} and {@link org.apache.tapestry.event.PageRenderListener} allow objects to know about key lifecycle events regarding a page. @author Howard Lewis Ship hlship@apache.org