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1   /*
2    * Licensed to the Apache Software Foundation (ASF) under one or more
3    * contributor license agreements.  See the NOTICE file distributed with
4    * this work for additional information regarding copyright ownership.
5    * The ASF licenses this file to You under the Apache License, Version 2.0
6    * (the "License"); you may not use this file except in compliance with
7    * the License.  You may obtain a copy of the License at
8    *
9    *     http://www.apache.org/licenses/LICENSE-2.0
10   *
11   * Unless required by applicable law or agreed to in writing, software
12   * distributed under the License is distributed on an "AS IS" BASIS,
13   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14   * See the License for the specific language governing permissions and
15   * limitations under the License.
16   */
17  package org.apache.tika.sax.xpath;
18  
19  /**
20   * XPath element matcher. A matcher instance encapsulates a specific
21   * state in XPath evaluation.
22   */
23  public class Matcher {
24  
25      /**
26       * State of a failed XPath evaluation, where nothing is matched.
27       * This matcher instance is used as a sentinel object whenever an
28       * XPath evaluation branch fails.
29       */
30      public static final Matcher FAIL = new Matcher();
31  
32      /**
33       * Returns the XPath evaluation state that results from descending
34       * to a child element with the given name.
35       *
36       * @param namespace element namespace or <code>null</code>
37       * @param name element name
38       * @return next XPath evaluation state
39       */
40      public Matcher descend(String namespace, String name) {
41          return FAIL;
42      }
43  
44      /**
45       * Returns <code>true</code> if the XPath expression matches
46       * the element associated with this evaluation state.
47       *
48       * @return XPath evaluation state for this element
49       */
50      public boolean matchesElement() {
51          return false;
52      }
53  
54      /**
55       * Returns <code>true</code> if the XPath expression matches the named
56       * attribute of the element associated with this evaluation state.
57       *
58       * @param namespace attribute namespace or <code>null</code>
59       * @param name attribute name
60       * @return XPath evaluation state for named attribute of this element
61       */
62      public boolean matchesAttribute(String namespace, String name) {
63          return false;
64      }
65  
66      /**
67       * Returns <code>true</code> if the XPath expression matches all text
68       * nodes whose parent is the element associated with this evaluation
69       * state.
70       *
71       * @return XPath evaluation state for text children of this element
72       */
73      public boolean matchesText() {
74          return false;
75      }
76  
77  }