001 /*
002 * JBoss DNA (http://www.jboss.org/dna)
003 * See the COPYRIGHT.txt file distributed with this work for information
004 * regarding copyright ownership. Some portions may be licensed
005 * to Red Hat, Inc. under one or more contributor license agreements.
006 * See the AUTHORS.txt file in the distribution for a full listing of
007 * individual contributors.
008 *
009 * Unless otherwise indicated, all code in JBoss DNA is licensed
010 * to you under the terms of the GNU Lesser General Public License as
011 * published by the Free Software Foundation; either version 2.1 of
012 * the License, or (at your option) any later version.
013 *
014 * JBoss DNA is distributed in the hope that it will be useful,
015 * but WITHOUT ANY WARRANTY; without even the implied warranty of
016 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
017 * Lesser General Public License for more details.
018 *
019 * You should have received a copy of the GNU Lesser General Public
020 * License along with this software; if not, write to the Free
021 * Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
022 * 02110-1301 USA, or see the FSF site: http://www.fsf.org.
023 */
024 package org.jboss.dna.jcr.cache;
025
026 import java.util.Iterator;
027 import java.util.UUID;
028 import net.jcip.annotations.Immutable;
029 import org.jboss.dna.common.collection.EmptyIterator;
030 import org.jboss.dna.graph.property.Name;
031 import org.jboss.dna.graph.property.PathFactory;
032 import org.jboss.dna.graph.property.Path.Segment;
033
034 /**
035 * An immutable implementation of {@link Children}.
036 */
037 @Immutable
038 public final class EmptyChildren implements Children, InternalChildren {
039
040 static final Iterator<ChildNode> EMPTY_ITERATOR = new EmptyIterator<ChildNode>();
041
042 private final UUID parentUuid;
043
044 public EmptyChildren( UUID parentUuid ) {
045 this.parentUuid = parentUuid;
046 }
047
048 /**
049 * {@inheritDoc}
050 *
051 * @see org.jboss.dna.jcr.cache.Children#size()
052 */
053 public int size() {
054 return 0;
055 }
056
057 /**
058 * {@inheritDoc}
059 *
060 * @see java.lang.Iterable#iterator()
061 */
062 public Iterator<ChildNode> iterator() {
063 return EMPTY_ITERATOR;
064 }
065
066 /**
067 * {@inheritDoc}
068 *
069 * @see org.jboss.dna.jcr.cache.Children#getParentUuid()
070 */
071 public UUID getParentUuid() {
072 return parentUuid;
073 }
074
075 /**
076 * {@inheritDoc}
077 *
078 * @see org.jboss.dna.jcr.cache.Children#getChild(java.util.UUID)
079 */
080 public ChildNode getChild( UUID uuid ) {
081 return null;
082 }
083
084 /**
085 * {@inheritDoc}
086 *
087 * @see org.jboss.dna.jcr.cache.Children#getChild(org.jboss.dna.graph.property.Path.Segment)
088 */
089 public ChildNode getChild( Segment segment ) {
090 return null;
091 }
092
093 /**
094 * {@inheritDoc}
095 *
096 * @see org.jboss.dna.jcr.cache.Children#getChildren(org.jboss.dna.graph.property.Name)
097 */
098 public Iterator<ChildNode> getChildren( Name name ) {
099 return EMPTY_ITERATOR;
100 }
101
102 /**
103 * {@inheritDoc}
104 *
105 * @see org.jboss.dna.jcr.cache.Children#getCountOfSameNameSiblingsWithName(org.jboss.dna.graph.property.Name)
106 */
107 public int getCountOfSameNameSiblingsWithName( Name name ) {
108 return 0;
109 }
110
111 /**
112 * {@inheritDoc}
113 *
114 * @see org.jboss.dna.jcr.cache.InternalChildren#with(org.jboss.dna.graph.property.Name, java.util.UUID,
115 * org.jboss.dna.graph.property.PathFactory)
116 */
117 public ChangedChildren with( Name newChildName,
118 UUID newChildUuid,
119 PathFactory pathFactory ) {
120 ChangedChildren result = new ChangedChildren(this);
121 result.add(newChildName, newChildUuid, pathFactory);
122 return result;
123 }
124
125 /**
126 * {@inheritDoc}
127 *
128 * @see org.jboss.dna.jcr.cache.InternalChildren#without(java.util.UUID, org.jboss.dna.graph.property.PathFactory)
129 */
130 public ChangedChildren without( UUID childUuid,
131 PathFactory pathFactory ) {
132 return new ChangedChildren(this.parentUuid);
133 }
134
135 /**
136 * {@inheritDoc}
137 *
138 * @see java.lang.Object#toString()
139 */
140 @Override
141 public String toString() {
142 return "";
143 }
144 }