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.List;
027 import java.util.ListIterator;
028 import java.util.UUID;
029 import net.jcip.annotations.NotThreadSafe;
030 import org.jboss.dna.graph.property.Name;
031 import org.jboss.dna.graph.property.Path;
032 import org.jboss.dna.graph.property.PathFactory;
033
034 /**
035 * A {@link NotThreadSafe non-thread safe} implementation of {@link Children} that can be modified in place. This is typically
036 * used to capture changes made within a session.
037 */
038 @NotThreadSafe
039 public class ChangedChildren extends ImmutableChildren {
040
041 public ChangedChildren( Children original ) {
042 super(original);
043 }
044
045 /**
046 * Creates an empty instance.
047 *
048 * @param parentUuid the UUID of the parent node
049 */
050 protected ChangedChildren( UUID parentUuid ) {
051 super(parentUuid);
052 }
053
054 protected ChangedChildren( ImmutableChildren original,
055 Name additionalChildName,
056 Path.Segment beforeChild,
057 UUID childUuid,
058 PathFactory pathFactory ) {
059 super(original, additionalChildName, beforeChild, childUuid, pathFactory);
060 }
061 /**
062 * {@inheritDoc}
063 *
064 * @see org.jboss.dna.jcr.cache.ImmutableChildren#with(org.jboss.dna.graph.property.Name, java.util.UUID,
065 * org.jboss.dna.graph.property.PathFactory)
066 */
067 @Override
068 public ChangedChildren with( Name newChildName,
069 UUID newChildUuid,
070 PathFactory pathFactory ) {
071 // Simply add the node to this object ...
072 super.add(newChildName, newChildUuid, pathFactory);
073 return this;
074 }
075
076 /**
077 * Create another Children object that is equivalent to this node but with the supplied child added before the named node.
078 *
079 * @param newChildName the name of the new child; may not be null
080 * @param beforeChild the path segment of the child before which this node should be added; may not be null
081 * @param newChildUuid the UUID of the new child; may not be null
082 * @param pathFactory the factory that can be used to create Path and/or Path.Segment instances.
083 * @return the new Children object; never null
084 */
085 public ChangedChildren with( Name newChildName,
086 Path.Segment beforeChild,
087 UUID newChildUuid,
088 PathFactory pathFactory ) {
089 return new ChangedChildren(this, newChildName, beforeChild, newChildUuid, pathFactory);
090 }
091
092 /**
093 * {@inheritDoc}
094 *
095 * @see org.jboss.dna.jcr.cache.ImmutableChildren#without(java.util.UUID, org.jboss.dna.graph.property.PathFactory)
096 */
097 @Override
098 public ChangedChildren without( UUID childUuid,
099 PathFactory pathFactory ) {
100 // Remove the object that has the same UUID (regardless of the current SNS index) ...
101 ChildNode toBeRemoved = childrenByUuid.get(childUuid);
102 if (toBeRemoved == null) {
103 return this;
104 }
105 // Remove the child from this object, then adjust the remaining child node instances that follow it ...
106 Name childName = toBeRemoved.getName();
107 List<ChildNode> childrenWithSameName = childrenByName.get(childName);
108 int snsIndex = toBeRemoved.getSnsIndex();
109 if (snsIndex > childrenWithSameName.size()) {
110 // The child node (with that SNS index) is no longer here) ...
111 return this;
112 }
113 ListIterator<ChildNode> iter = childrenWithSameName.listIterator(--snsIndex);
114 assert iter.hasNext();
115 ChildNode willBeRemoved = iter.next();
116 assert willBeRemoved == toBeRemoved;
117 childrenByUuid.remove(toBeRemoved.getUuid());
118 iter.remove(); // removes the item that was last returned from 'next()'
119 while (iter.hasNext()) {
120 ChildNode next = iter.next();
121 ChildNode newNext = next.with(pathFactory.createSegment(childName, ++snsIndex));
122 childrenByUuid.put(newNext.getUuid(), newNext);
123 iter.set(newNext);
124 }
125 return this;
126 }
127
128 }