Source code: org/apache/commons/jxpath/ExpressionContext.java
1 /*
2 * Copyright 1999-2004 The Apache Software Foundation
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 * http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16 package org.apache.commons.jxpath;
17
18 import java.util.List;
19
20 /**
21 * If an extenstion function has an argument of type ExpressionContext,
22 * it can gain access to the current node of an XPath expression context.
23 * <p>
24 * Example:
25 * <blockquote><pre>
26 * public class MyExtenstionFunctions {
27 * public static String objectType(ExpressionContext context){
28 * Object value = context.getContextNodePointer().getValue();
29 * if (value == null){
30 * return "null";
31 * }
32 * return value.getClass().getName();
33 * }
34 * }
35 * </pre></blockquote>
36 *
37 * You can then register this extension function using a {@link ClassFunctions
38 * ClassFunctions} object and call it like this:
39 * <blockquote><pre>
40 * "/descendent-or-self::node()[ns:objectType() = 'java.util.Date']"
41 * </pre></blockquote>
42 * This expression will find all nodes of the graph that are dates.
43 */
44 public interface ExpressionContext {
45
46 /**
47 * Get the JXPathContext in which this function is being evaluated.
48 *
49 * @return A list representing the current context nodes.
50 */
51 JXPathContext getJXPathContext();
52
53 /**
54 * Get the current context node.
55 *
56 * @return The current context node pointer.
57 */
58 Pointer getContextNodePointer();
59
60 /**
61 * Get the current context node list. Each element of the list is
62 * a Pointer.
63 *
64 * @return A list representing the current context nodes.
65 */
66 List getContextNodeList();
67
68 /**
69 * Returns the current context position.
70 */
71 int getPosition();
72 }