1 /*
2 * $Header: /home/projects/jaxen/scm/jaxen/src/java/main/org/jaxen/util/SingleObjectIterator.java,v 1.8 2006/11/09 18:20:12 elharo Exp $
3 * $Revision: 1.8 $
4 * $Date: 2006/11/09 18:20:12 $
5 *
6 * ====================================================================
7 *
8 * Copyright 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 are
13 * met:
14 *
15 * * Redistributions of source code must retain the above copyright
16 * notice, this list of conditions and the following disclaimer.
17 *
18 * * Redistributions in binary form must reproduce the above copyright
19 * notice, this list of conditions and the following disclaimer in the
20 * documentation and/or other materials provided with the distribution.
21 *
22 * * Neither the name of the Jaxen Project nor the names of its
23 * contributors may be used to endorse or promote products derived
24 * from this software without specific prior written permission.
25 *
26 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
27 * IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
28 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
29 * PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER
30 * OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
31 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
32 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
33 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
34 * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
35 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
36 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
37 *
38 * ====================================================================
39 * This software consists of voluntary contributions made by many
40 * individuals on behalf of the Jaxen Project and was originally
41 * created by bob mcwhirter <bob@werken.com> and
42 * James Strachan <jstrachan@apache.org>. For more information on the
43 * Jaxen Project, please see <http://www.jaxen.org/>.
44 *
45 * $Id: SingleObjectIterator.java,v 1.8 2006/11/09 18:20:12 elharo Exp $
46 */
47
48
49 package org.jaxen.util;
50
51 import java.util.Iterator;
52 import java.util.NoSuchElementException;
53
54 /***
55 * Simple utility class that wraps an iterator around one object.
56 * This is a little more efficent than creating a one-object list.
57 *
58 */
59 public class SingleObjectIterator implements Iterator
60 {
61
62 private Object object;
63 private boolean seen;
64
65 /***
66 * Creates a new single object iterator.
67 *
68 * @param object the object to iterate over
69 */
70 public SingleObjectIterator(Object object)
71 {
72 this.object = object;
73 this.seen = false;
74 }
75
76
77 /***
78 * Returns true if this iterator's element has not yet been seen; false if it has.
79 *
80 * @return true if this iterator has another element; false if it doesn't
81 *
82 * @see java.util.Iterator#hasNext()
83 */
84 public boolean hasNext()
85 {
86 return ! this.seen;
87 }
88
89 /***
90 * Returns the single element in this iterator if it has not yet
91 * been seen.
92 *
93 * @return the next element in this iterator
94 *
95 * @throws NoSuchElementException if the element has already been seen
96 *
97 * @see java.util.Iterator#next()
98 */
99 public Object next()
100 {
101 if ( hasNext() )
102 {
103 this.seen = true;
104 return this.object;
105 }
106
107 throw new NoSuchElementException();
108 }
109
110 /***
111 * This operation is not supported.
112 *
113 * @throws UnsupportedOperationException always
114 */
115 public void remove()
116 {
117 throw new UnsupportedOperationException();
118 }
119
120 }