KickJava   Java API By Example, From Geeks To Geeks.

Java > Open Source Codes > org > dom4j > tree > FilterIterator


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 JavaDoc;
11 import java.util.NoSuchElementException JavaDoc;
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 JavaDoc {
25     protected Iterator JavaDoc proxy;
26
27     private Object JavaDoc next;
28
29     private boolean first = true;
30
31     public FilterIterator(Iterator JavaDoc 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 JavaDoc next() throws NoSuchElementException JavaDoc {
45         if (!hasNext()) {
46             throw new NoSuchElementException JavaDoc();
47         }
48
49         Object JavaDoc 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 JavaDoc();
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 JavaDoc element);
76
77     protected Object JavaDoc findNext() {
78         if (proxy != null) {
79             while (proxy.hasNext()) {
80                 Object JavaDoc 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  */
130
Popular Tags