1 package com.sri.emo.dbobj.model_tree;
2
3 /***
4 * Specific to the Iterator inherant with the model tree. Fires events
5 * whenever we descend a node in the tree or ascend a node in the tree. Does
6 * not fire for siblings.
7 *
8 * @author Michael Rimov
9 */
10 public interface TreeTraversalListener {
11
12 /***
13 * <tt>Special Case</tt> for no listeners.
14 */
15 final TreeTraversalListener NULL_LISTENER = new TreeTraversalListener() {
16 public void descendModelTree(ModelNode newCurrentNode) {
17
18 }
19
20 public void ascendModelTree(ModelNode newCurrentNode) {
21
22 }
23 };
24
25
26 void descendModelTree(ModelNode newCurrentNode);
27
28 void ascendModelTree(ModelNode newCurrentNode);
29 }