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; 67 import java.util.Iterator; 68 import java.util.LinkedList; 69 import java.util.NoSuchElementException; 70 import java.util.Set; 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 80 { 81 82 private LinkedList iteratorStack; 83 private Navigator navigator; 84 85 private Set created; 86 87 public StackedIterator(Object contextNode, 88 Navigator navigator) 89 { 90 this.iteratorStack = new LinkedList(); 91 this.created = new HashSet(); 92 93 init( contextNode, 94 navigator ); 95 } 96 97 protected StackedIterator() 98 { 99 this.iteratorStack = new LinkedList(); 100 this.created = new HashSet(); 101 } 102 103 protected void init(Object contextNode, 104 Navigator navigator) 105 { 106 this.navigator = navigator; 107 108 //pushIterator( internalCreateIterator( contextNode ) ); 109 } 110 111 protected Iterator internalCreateIterator(Object 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 curIter = currentIterator(); 126 127 if ( curIter == null ) 128 { 129 return false; 130 } 131 132 return curIter.hasNext(); 133 } 134 135 public Object next() throws NoSuchElementException 136 { 137 if ( ! hasNext() ) 138 { 139 throw new NoSuchElementException(); 140 } 141 142 Iterator curIter = currentIterator(); 143 Object object = curIter.next(); 144 145 pushIterator( internalCreateIterator( object ) ); 146 147 return object; 148 } 149 150 public void remove() throws UnsupportedOperationException 151 { 152 throw new UnsupportedOperationException(); 153 } 154 155 abstract protected Iterator createIterator(Object contextNode); 156 157 protected void pushIterator(Iterator iter) 158 { 159 if ( iter != null ) 160 { 161 this.iteratorStack.addFirst(iter); //addLast( iter ); 162 } 163 } 164 165 private Iterator currentIterator() 166 { 167 while ( iteratorStack.size() > 0 ) 168 { 169 Iterator curIter = (Iterator) 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 }