KickJava   Java API By Example, From Geeks To Geeks.

Java > Open Source Codes > org > jaxen > util > StackedIterator


1 /*
2  * $Header: /home/projects/jaxen/scm/jaxen/src/java/main/org/jaxen/util/StackedIterator.java,v 1.10 2005/01/30 03:14:41 elharo Exp $
3  * $Revision: 1.10 $
4  * $Date: 2005/01/30 03:14:41 $
5  *
6  * ====================================================================
7  *
8  * Copyright (C) 2000-2002 bob mcwhirter & James Strachan.
9  * All rights reserved.
10  *
11  * Redistribution and use in source and binary forms, with or without
12  * modification, are permitted provided that the following conditions
13  * are met:
14  *
15  * 1. Redistributions of source code must retain the above copyright
16  * notice, this list of conditions, and the following disclaimer.
17  *
18  * 2. Redistributions in binary form must reproduce the above copyright
19  * notice, this list of conditions, and the disclaimer that follows
20  * these conditions in the documentation and/or other materials
21  * provided with the distribution.
22  *
23  * 3. The name "Jaxen" must not be used to endorse or promote products
24  * derived from this software without prior written permission. For
25  * written permission, please contact license@jaxen.org.
26  *
27  * 4. Products derived from this software may not be called "Jaxen", nor
28  * may "Jaxen" appear in their name, without prior written permission
29  * from the Jaxen Project Management (pm@jaxen.org).
30  *
31  * In addition, we request (but do not require) that you include in the
32  * end-user documentation provided with the redistribution and/or in the
33  * software itself an acknowledgement equivalent to the following:
34  * "This product includes software developed by the
35  * Jaxen Project (http://www.jaxen.org/)."
36  * Alternatively, the acknowledgment may be graphical using the logos
37  * available at http://www.jaxen.org/
38  *
39  * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
40  * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
41  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
42  * DISCLAIMED. IN NO EVENT SHALL THE Jaxen AUTHORS OR THE PROJECT
43  * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
44  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
45  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
46  * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
47  * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
48  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
49  * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
50  * SUCH DAMAGE.
51  *
52  * ====================================================================
53  * This software consists of voluntary contributions made by many
54  * individuals on behalf of the Jaxen Project and was originally
55  * created by bob mcwhirter <bob@werken.com> and
56  * James Strachan <jstrachan@apache.org>. For more information on the
57  * Jaxen Project, please see <http://www.jaxen.org/>.
58  *
59  * $Id: StackedIterator.java,v 1.10 2005/01/30 03:14:41 elharo Exp $
60  */
61
62
63
64 package org.jaxen.util;
65
66 import java.util.HashSet JavaDoc;
67 import java.util.Iterator JavaDoc;
68 import java.util.LinkedList JavaDoc;
69 import java.util.NoSuchElementException JavaDoc;
70 import java.util.Set JavaDoc;
71
72 import org.jaxen.Navigator;
73
74 /**
75  * @deprecated this iterator is no longer used to implement any of the Jaxen axes. If you have implemented
76  * a navigator-specific axis based on this class, take a look at the DescendantAxisIterator for ideas
77  * on how to remove that dependency.
78  */
79 public abstract class StackedIterator implements Iterator JavaDoc
80 {
81
82     private LinkedList JavaDoc iteratorStack;
83     private Navigator navigator;
84
85     private Set JavaDoc created;
86
87     public StackedIterator(Object JavaDoc contextNode,
88                            Navigator navigator)
89     {
90         this.iteratorStack = new LinkedList JavaDoc();
91         this.created = new HashSet JavaDoc();
92
93         init( contextNode,
94               navigator );
95     }
96
97     protected StackedIterator()
98     {
99         this.iteratorStack = new LinkedList JavaDoc();
100         this.created = new HashSet JavaDoc();
101     }
102
103     protected void init(Object JavaDoc contextNode,
104                         Navigator navigator)
105     {
106         this.navigator = navigator;
107         
108         //pushIterator( internalCreateIterator( contextNode ) );
109 }
110
111     protected Iterator JavaDoc internalCreateIterator(Object JavaDoc contextNode)
112     {
113         if ( this.created.contains( contextNode ) )
114         {
115             return null;
116         }
117
118         this.created.add( contextNode );
119
120         return createIterator( contextNode );
121     }
122
123     public boolean hasNext()
124     {
125         Iterator JavaDoc curIter = currentIterator();
126
127         if ( curIter == null )
128         {
129             return false;
130         }
131
132         return curIter.hasNext();
133     }
134
135     public Object JavaDoc next() throws NoSuchElementException JavaDoc
136     {
137         if ( ! hasNext() )
138         {
139             throw new NoSuchElementException JavaDoc();
140         }
141
142         Iterator JavaDoc curIter = currentIterator();
143         Object JavaDoc object = curIter.next();
144
145         pushIterator( internalCreateIterator( object ) );
146
147         return object;
148     }
149
150     public void remove() throws UnsupportedOperationException JavaDoc
151     {
152         throw new UnsupportedOperationException JavaDoc();
153     }
154
155     abstract protected Iterator JavaDoc createIterator(Object JavaDoc contextNode);
156
157     protected void pushIterator(Iterator JavaDoc iter)
158     {
159         if ( iter != null )
160         {
161             this.iteratorStack.addFirst(iter); //addLast( iter );
162 }
163     }
164
165     private Iterator JavaDoc currentIterator()
166     {
167         while ( iteratorStack.size() > 0 )
168         {
169             Iterator JavaDoc curIter = (Iterator JavaDoc) iteratorStack.getFirst();
170
171             if ( curIter.hasNext() )
172             {
173                 return curIter;
174             }
175
176             iteratorStack.removeFirst();
177         }
178
179         return null;
180     }
181
182     protected Navigator getNavigator()
183     {
184         return this.navigator;
185     }
186 }
187
Popular Tags