y.base
Interface GraphListener

All Superinterfaces:

EventListener

All Known Implementing Classes:

Graph2DUndoManager

public interface GraphListener

extends EventListener

The listener interface for receiving graph events. The class that is interested in processing a graph event implements this interface. The object created with that class is then registered with a graph. When the graph structurally changes, the listener object's onGraphEvent method is invoked.

The listener object's onGraphEvent method is also invoked on so-called pre- and post events emitted by the graph. These events signal that a potentially empty sequence of graph events is about to be emitted (pre event) or that the sequence is completed (post event).

E.g. if a node is about to be removed in a graph then first a pre event is emited then a potentially empty sequence of edge removals then a node removal and finally a post event that concludes the logically coherent sequence of structural graph changes.

Pre and post events must constitute a well-formed bracket-structure, e.g. ( ( ( ) ) () ).

Method Summary

void	onGraphEvent(GraphEvent e) Invoked when the structure of the graph has changed.

Method Detail

onGraphEvent

public void onGraphEvent(GraphEvent e)

Invoked when the structure of the graph has changed. The code written for this method performs the operations that need to occur when the graph changes.