1 /*
2 * ModeShape (http://www.modeshape.org)
3 * See the COPYRIGHT.txt file distributed with this work for information
4 * regarding copyright ownership. Some portions may be licensed
5 * to Red Hat, Inc. under one or more contributor license agreements.
6 * See the AUTHORS.txt file in the distribution for a full listing of
7 * individual contributors.
8 *
9 * ModeShape is free software. Unless otherwise indicated, all code in ModeShape
10 * is licensed to you under the terms of the GNU Lesser General Public License as
11 * published by the Free Software Foundation; either version 2.1 of
12 * the License, or (at your option) any later version.
13 *
14 * ModeShape is distributed in the hope that it will be useful,
15 * but WITHOUT ANY WARRANTY; without even the implied warranty of
16 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
17 * Lesser General Public License for more details.
18 *
19 * You should have received a copy of the GNU Lesser General Public
20 * License along with this software; if not, write to the Free
21 * Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
22 * 02110-1301 USA, or see the FSF site: http://www.fsf.org.
23 */
24 package org.modeshape.graph.connector.base;
25
26 import java.util.Map;
27 import java.util.UUID;
28 import java.util.concurrent.locks.ReadWriteLock;
29 import net.jcip.annotations.NotThreadSafe;
30
31 /**
32 * The {@link Workspace} implementation that represents all nodes as {@link MapNode} objects and stores them within a
33 * {@link Map} keyed by their UUID.
34 * <p>
35 * Subclasses are required to provide thread-safe access and modification of the state within the encapsulated map, since multiple
36 * {@link Transaction} implementations may be {@link Transaction#commit() committing} changes to the map at the same time.
37 * However, this class does not provide any thread-safety, since the nature of the thread-safety will almost certainly depend on
38 * the actual map implementation. For example, a subclass may use a {@link ReadWriteLock lock}, or it may use a map implementation
39 * that provides the thread-safety.
40 * </p>
41 *
42 * @param <NodeType> the type of node
43 */
44 @NotThreadSafe
45 public class StandardMapWorkspace<NodeType extends MapNode> extends MapWorkspace<NodeType> {
46
47 private final Map<UUID, NodeType> nodesByUuid;
48
49 /**
50 * Create a new instance of the workspace.
51 *
52 * @param name the workspace name; may not be null
53 * @param nodesByUuid the map of nodes keyed by their UUIDs; may not be null
54 * @param rootNode the root node that is expected to already exist in the map
55 */
56 public StandardMapWorkspace( String name,
57 Map<UUID, NodeType> nodesByUuid,
58 NodeType rootNode ) {
59 super(name, rootNode);
60 this.nodesByUuid = nodesByUuid;
61 UUID rootNodeUuid = rootNode.getUuid();
62 if (!this.nodesByUuid.containsKey(rootNodeUuid)) {
63 this.nodesByUuid.put(rootNodeUuid, rootNode);
64 }
65 assert this.nodesByUuid != null;
66 }
67
68 /**
69 * Create a new instance of the workspace.
70 *
71 * @param name the workspace name; may not be null
72 * @param nodesByUuid the map of nodes keyed by their UUIDs; may not be null
73 * @param originalToClone the workspace that is to be cloned; may not be null
74 */
75 public StandardMapWorkspace( String name,
76 Map<UUID, NodeType> nodesByUuid,
77 StandardMapWorkspace<NodeType> originalToClone ) {
78 super(name, originalToClone);
79 this.nodesByUuid = nodesByUuid;
80 this.nodesByUuid.putAll(originalToClone.nodesByUuid); // make a copy
81 assert this.nodesByUuid != null;
82 }
83
84 /**
85 * Get the node with the supplied UUID.
86 *
87 * @param uuid the UUID of the node
88 * @return the node state as known by this workspace, or null if no such node exists in this workspace
89 */
90 @Override
91 public NodeType getNode( UUID uuid ) {
92 return nodesByUuid.get(uuid);
93 }
94
95 /**
96 * Add the node into this workspace's map, overwriting any previous record of the node
97 *
98 * @param node the new node; may not be null
99 * @return the previous node state, or null if the node is new to this workspace
100 */
101 @Override
102 public NodeType putNode( NodeType node ) {
103 return nodesByUuid.put(node.getUuid(), node);
104 }
105
106 /**
107 * Remove and return the node with the supplied UUID. This method will never remove the root node.
108 *
109 * @param uuid the UUID of the node to be removed
110 * @return the node that was removed, or null if the supplied UUID is the root node's UUID or if this workspace does not
111 * contain a node with the supplied UUID
112 */
113 @Override
114 public NodeType removeNode( UUID uuid ) {
115 return rootNodeUuid.equals(uuid) ? null : nodesByUuid.remove(uuid);
116 }
117
118 /**
119 * Remove all of the nodes in this workspace, and make sure there is a single root node with no properties and no children.
120 */
121 @Override
122 @SuppressWarnings( "unchecked" )
123 public void removeAll() {
124 NodeType newRootNode = (NodeType)getRootNode().withoutChildren().withoutProperties().freeze();
125 nodesByUuid.clear();
126 nodesByUuid.put(newRootNode.getUuid(), newRootNode);
127 }
128 }