KickJava   Java API By Example, From Geeks To Geeks.

Java > Open Source Codes > org > apache > cayenne > exp > TraversalHandler


1 /*****************************************************************
2  * Licensed to the Apache Software Foundation (ASF) under one
3  * or more contributor license agreements. See the NOTICE file
4  * distributed with this work for additional information
5  * regarding copyright ownership. The ASF licenses this file
6  * to you under the Apache License, Version 2.0 (the
7  * "License"); you may not use this file except in compliance
8  * with the License. You may obtain a copy of the License at
9  *
10  * http://www.apache.org/licenses/LICENSE-2.0
11  *
12  * Unless required by applicable law or agreed to in writing,
13  * software distributed under the License is distributed on an
14  * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
15  * KIND, either express or implied. See the License for the
16  * specific language governing permissions and limitations
17  * under the License.
18  ****************************************************************/
19
20 package org.apache.cayenne.exp;
21
22 /**
23  * Expression visitor interface. Defines callback methods invoked when
24  * walking the expression using {@link Expression#traverse(TraversalHandler)}.
25  *
26  * @author Andrus Adamchik
27  */
28 public interface TraversalHandler {
29
30     /**
31      * Called during traversal after a child of expression
32      * has been visited.
33      */
34     public void finishedChild(
35         Expression node,
36         int childIndex,
37         boolean hasMoreChildren);
38   
39     /**
40      * Called during the traversal before an expression node children
41      * processing is started.
42      *
43      * @since 1.1
44      */
45     public void startNode(Expression node, Expression parentNode);
46     
47     /**
48      * Called during the traversal after an expression node children
49      * processing is finished.
50      *
51      * @since 1.1
52      */
53     public void endNode(Expression node, Expression parentNode);
54     
55     /**
56      * Called during the traversal when a leaf non-expression node
57      * is encountered.
58      */
59     public void objectNode(Object JavaDoc leaf, Expression parentNode);
60 }
61
Popular Tags