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Java > Open Source Codes > net > sf > saxon > pull > ElementNameTracker


1 package net.sf.saxon.pull;
2
3 import net.sf.saxon.trans.XPathException;
4
5 /**
6  * This is a filter that can be added to a pull pipeline to remember element names so that
7  * they are available immediately after the END_ELEMENT event is notified
8  */
9 public class ElementNameTracker extends PullFilter {
10
11     private int[] namestack = new int[20];
12     int used = 0;
13     int elementJustEnded = -1;
14
15     public ElementNameTracker(PullProvider base) {
16         super(base);
17     }
18
19     /**
20      * Get the next event.
21      * <p/>
22      * <p>Note that a subclass that overrides this method is responsible for ensuring
23      * that current() works properly. This can be achieved by setting the field
24      * currentEvent to the event returned by any call on next().</p>
25      *
26      * @return an integer code indicating the type of event. The code
27      * {@link #END_OF_INPUT} is returned at the end of the sequence.
28      */
29
30     public int next() throws XPathException {
31         currentEvent = super.next();
32         if (currentEvent == START_ELEMENT) {
33             int nc = getNameCode();
34             if (used >= namestack.length) {
35                 int[] n2 = new int[used*2];
36                 System.arraycopy(namestack, 0, n2, 0, used);
37                 namestack = n2;
38             }
39             namestack[used++] = nc;
40         } else if (currentEvent == END_ELEMENT) {
41             elementJustEnded = namestack[--used];
42         }
43         return currentEvent;
44     }
45
46     /**
47      * Get the nameCode identifying the name of the current node. This method
48      * can be used after the {@link #START_ELEMENT}, {@link #PROCESSING_INSTRUCTION},
49      * {@link #ATTRIBUTE}, or {@link #NAMESPACE} events. With some PullProvider implementations,
50      * including this one, it can also be used after {@link #END_ELEMENT}: in fact, that is the
51      * main purpose of this class.
52      * If called at other times, the result is undefined and may result in an IllegalStateException.
53      * If called when the current node is an unnamed namespace node (a node representing the default namespace)
54      * the returned value is -1.
55      *
56      * @return the nameCode. The nameCode can be used to obtain the prefix, local name,
57      * and namespace URI from the name pool.
58      */
59
60     public int getNameCode() {
61         if (currentEvent == END_ELEMENT) {
62             return elementJustEnded;
63         } else {
64             return super.getNameCode();
65         }
66     }
67 }
68
69 //
70 // The contents of this file are subject to the Mozilla Public License Version 1.0 (the "License");
71 // you may not use this file except in compliance with the License. You may obtain a copy of the
72 // License at http://www.mozilla.org/MPL/
73 //
74 // Software distributed under the License is distributed on an "AS IS" basis,
75 // WITHOUT WARRANTY OF ANY KIND, either express or implied.
76 // See the License for the specific language governing rights and limitations under the License.
77 //
78 // The Original Code is: all this file.
79 //
80 // The Initial Developer of the Original Code is Michael H. Kay.
81 //
82 // Portions created by (your name) are Copyright (C) (your legal entity). All Rights Reserved.
83 //
84 // Contributor(s): none.
85 //
86
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