1 /*
2 * Copyright 2001-2005 (C) MetaStuff, Ltd. All Rights Reserved.
3 *
4 * This software is open source.
5 * See the bottom of this file for the licence.
6 */
7
8 package org.dom4j.tree;
9
10 import java.util.Iterator;
11 import java.util.NoSuchElementException;
12
13 /***
14 * <p>
15 * <code>FilterIterator</code> is an abstract base class which is useful for
16 * implementors of {@link Iterator}which filter an existing iterator.
17 * </p>
18 *
19 * @author <a href="mailto:james.strachan@metastuff.com">James Strachan </a>
20 * @version $Revision: 1.10 $
21 *
22 * @deprecated THIS CLASS WILL BE REMOVED IN dom4j-1.6 !!
23 */
24 public abstract class FilterIterator implements Iterator {
25 protected Iterator proxy;
26
27 private Object next;
28
29 private boolean first = true;
30
31 public FilterIterator(Iterator proxy) {
32 this.proxy = proxy;
33 }
34
35 public boolean hasNext() {
36 if (first) {
37 next = findNext();
38 first = false;
39 }
40
41 return next != null;
42 }
43
44 public Object next() throws NoSuchElementException {
45 if (!hasNext()) {
46 throw new NoSuchElementException();
47 }
48
49 Object answer = this.next;
50 this.next = findNext();
51
52 return answer;
53 }
54
55 /***
56 * Always throws UnsupportedOperationException as this class does look-ahead
57 * with its internal iterator.
58 *
59 * @throws UnsupportedOperationException
60 * always
61 */
62 public void remove() {
63 throw new UnsupportedOperationException();
64 }
65
66 /***
67 * Filter method to perform some matching on the given element.
68 *
69 * @param element
70 * DOCUMENT ME!
71 *
72 * @return true if the given element matches the filter and should be appear
73 * in the iteration
74 */
75 protected abstract boolean matches(Object element);
76
77 protected Object findNext() {
78 if (proxy != null) {
79 while (proxy.hasNext()) {
80 Object nextObject = proxy.next();
81
82 if ((nextObject != null) && matches(nextObject)) {
83 return nextObject;
84 }
85 }
86
87 proxy = null;
88 }
89
90 return null;
91 }
92 }
93
94 /*
95 * Redistribution and use of this software and associated documentation
96 * ("Software"), with or without modification, are permitted provided that the
97 * following conditions are met:
98 *
99 * 1. Redistributions of source code must retain copyright statements and
100 * notices. Redistributions must also contain a copy of this document.
101 *
102 * 2. Redistributions in binary form must reproduce the above copyright notice,
103 * this list of conditions and the following disclaimer in the documentation
104 * and/or other materials provided with the distribution.
105 *
106 * 3. The name "DOM4J" must not be used to endorse or promote products derived
107 * from this Software without prior written permission of MetaStuff, Ltd. For
108 * written permission, please contact dom4j-info@metastuff.com.
109 *
110 * 4. Products derived from this Software may not be called "DOM4J" nor may
111 * "DOM4J" appear in their names without prior written permission of MetaStuff,
112 * Ltd. DOM4J is a registered trademark of MetaStuff, Ltd.
113 *
114 * 5. Due credit should be given to the DOM4J Project - http://www.dom4j.org
115 *
116 * THIS SOFTWARE IS PROVIDED BY METASTUFF, LTD. AND CONTRIBUTORS ``AS IS'' AND
117 * ANY EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
118 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
119 * ARE DISCLAIMED. IN NO EVENT SHALL METASTUFF, LTD. OR ITS CONTRIBUTORS BE
120 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
121 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
122 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
123 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
124 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
125 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
126 * POSSIBILITY OF SUCH DAMAGE.
127 *
128 * Copyright 2001-2005 (C) MetaStuff, Ltd. All Rights Reserved.
129 */