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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  /***
19   * The  {@link JXPathContext#createPath JXPathContext.createPath()} method of
20   * JXPathContext can create missing objects as it traverses an XPath; it
21   * utilizes an AbstractFactory for that purpose. Install a factory on
22   * JXPathContext by calling {@link JXPathContext#setFactory JXPathContext.
23   * setFactory()}.
24   * <p>
25   * All  methods of this class return false.  Override any of them to return true
26   * to indicate that the factory has successfully created the described object.
27   *
28   * @author Dmitri Plotnikov
29   * @version $Revision: 1.8 $ $Date: 2004/02/29 14:17:42 $
30   */
31  public abstract class AbstractFactory {
32  
33      /***
34       * The  parameters may describe a collection element or an individual
35       * object. It is up to the factory to infer which one it is. If it is a
36       * collection, the factory should check if the collection exists.  If not,
37       * it should create the collection. Then it should create the index'th
38       * element of the collection and return true.
39       * <p>
40       * 
41       * @param context can be used to evaluate other XPaths, get to variables
42       * etc.
43       * @param pointer describes the location of the node to be created
44       * @param parent is the object that will server as a parent of the new
45       * object
46       * @param name is the name of the child of the parent that needs to be
47       * created. In the case of DOM may be qualified.
48       * @param index is used if the pointer represents a collection element. You
49       * may need to expand or even create the collection to accomodate the new
50       * element.
51       * 
52       * @return true if the object was successfully created
53       */
54      public boolean createObject(JXPathContext context, Pointer pointer, 
55                                  Object parent, String name, int index) 
56      {
57          return false;
58      }
59  
60      /***
61       * Declare the specified variable
62       * 
63       * @param context hosts variable pools. See 
64       * {@link JXPathContext#getVariables() JXPathContext.getVariables()}
65       * @param name is the name of the variable without the "$" sign
66       * 
67       * @return true if the variable was successfully defined
68       */
69      public boolean declareVariable(JXPathContext context, String name) {
70          return false;
71      }
72  }