1 /**
2 * This file Copyright (c) 2011 Magnolia International
3 * Ltd. (http://www.magnolia-cms.com). All rights reserved.
4 *
5 *
6 * This file is dual-licensed under both the Magnolia
7 * Network Agreement and the GNU General Public License.
8 * You may elect to use one or the other of these licenses.
9 *
10 * This file is distributed in the hope that it will be
11 * useful, but AS-IS and WITHOUT ANY WARRANTY; without even the
12 * implied warranty of MERCHANTABILITY or FITNESS FOR A
13 * PARTICULAR PURPOSE, TITLE, or NONINFRINGEMENT.
14 * Redistribution, except as permitted by whichever of the GPL
15 * or MNA you select, is prohibited.
16 *
17 * 1. For the GPL license (GPL), you can redistribute and/or
18 * modify this file under the terms of the GNU General
19 * Public License, Version 3, as published by the Free Software
20 * Foundation. You should have received a copy of the GNU
21 * General Public License, Version 3 along with this program;
22 * if not, write to the Free Software Foundation, Inc., 51
23 * Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
24 *
25 * 2. For the Magnolia Network Agreement (MNA), this file
26 * and the accompanying materials are made available under the
27 * terms of the MNA which accompanies this distribution, and
28 * is available at http://www.magnolia-cms.com/mna.html
29 *
30 * Any modifications to this file must keep this entire header
31 * intact.
32 *
33 */
34 package info.magnolia.jcr.iterator;
35
36 import java.util.Arrays;
37 import java.util.List;
38
39 import javax.jcr.Node;
40 import javax.jcr.NodeIterator;
41
42 import org.apache.commons.collections.iterators.IteratorChain;
43
44
45 /**
46 * An implementation of {@link NodeIterator} which will chain several iterators making them behave like one.
47 *
48 * @version $Id$
49 */
50 public class ChainedNodeIterator implements NodeIterator {
51
52 private final IteratorChain iterators = new IteratorChain();
53 private long position = 0;
54 private long size = 0;
55
56 public ChainedNodeIterator(List<NodeIterator> iterators) {
57 for(NodeIterator it : iterators) {
58 this.iterators.addIterator(it);
59
60 // If any of the iterators returns -1 the we must also return -1
61 long s = it.getSize();
62 if (size != -1) {
63 if (s == -1) {
64 size = -1;
65 } else {
66 size += s;
67 }
68 }
69 }
70 }
71
72 public ChainedNodeIterator(NodeIterator... iterators) {
73 this(Arrays.asList(iterators));
74 }
75
76 @Override
77 public void skip(long skipNum) {
78 while (skipNum > 0) {
79 next();
80 skipNum--;
81 }
82 }
83
84 @Override
85 public long getSize() {
86 return size;
87 }
88
89 @Override
90 public long getPosition() {
91 return position;
92 }
93
94 @Override
95 public boolean hasNext() {
96 return iterators.hasNext();
97 }
98
99 @Override
100 public Object next() {
101 return nextNode();
102 }
103
104 @Override
105 public void remove() {
106 iterators.remove();
107 }
108
109 @Override
110 public Node nextNode() {
111 Node node = (Node)iterators.next();
112 position++;
113 return node;
114 }
115 }