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.federation;
25
26 import java.util.ArrayList;
27 import java.util.Collection;
28 import java.util.Collections;
29 import java.util.HashMap;
30 import java.util.List;
31 import java.util.Map;
32 import java.util.UUID;
33 import net.jcip.annotations.Immutable;
34 import org.modeshape.graph.ExecutionContext;
35 import org.modeshape.graph.Location;
36 import org.modeshape.graph.property.Name;
37 import org.modeshape.graph.property.Path;
38 import org.modeshape.graph.property.PathFactory;
39 import org.modeshape.graph.property.Property;
40
41 /**
42 * A Projector for federated repository configurations that are an offset, direct one-for-one mirror against a single source
43 * repository that is projected below the federated root. In other words, the federated repository has a single projection with a
44 * single "/something/below/root => /" rule.
45 */
46 @Immutable
47 abstract class ProjectorWithPlaceholders implements Projector {
48
49 private Map<Path, PlaceholderNode> placeholderNodesByPath;
50 private Map<UUID, PlaceholderNode> placeholderNodesByUuid;
51
52 ProjectorWithPlaceholders( ExecutionContext context,
53 List<Projection> projections ) {
54 placeholderNodesByPath = new HashMap<Path, PlaceholderNode>();
55 placeholderNodesByUuid = new HashMap<UUID, PlaceholderNode>();
56 // Use the execution context of the source to load the projected nodes ...
57 Collection<PlaceholderNode> placeholders = new ArrayList<PlaceholderNode>();
58 loadPlaceholderNodes(context, projections, placeholders);
59 for (PlaceholderNode placeholder : placeholders) {
60 placeholderNodesByPath.put(placeholder.location().getPath(), placeholder);
61 placeholderNodesByUuid.put(placeholder.location().getUuid(), placeholder);
62 }
63 }
64
65 /**
66 * Determine whether the specified location is a placeholder node.
67 *
68 * @param location the location of the node; may not be null
69 * @return the placeholder node, or null if the supplied location does not designate a placeholder node
70 */
71 public PlaceholderNode isPlaceholder( Location location ) {
72 Path path = location.getPath();
73 if (path != null) {
74 return placeholderNodesByPath.get(path);
75 }
76 UUID uuid = location.getUuid();
77 if (uuid != null) {
78 return placeholderNodesByUuid.get(uuid);
79 }
80 return null;
81 }
82
83 /**
84 * Load the placeholder nodes for this repository. This method does not modify any state of this instance, but instead
85 * populates the supplied map.
86 * <p>
87 * A placeholder is created for each node above the projections' {@link Projection#getTopLevelPathsInRepository(PathFactory)
88 * top-level paths} in the federated repository. Thus, the projected node immediately above a top-level path will contain the
89 * top-level path as a child.
90 * </p>
91 *
92 * @param context the context in which the placeholder nodes should be materialized; may not be null
93 * @param projections the projections; may not be null
94 * @param placeholderNodes the collection into which should be placed the materialized placeholders
95 */
96 protected static void loadPlaceholderNodes( ExecutionContext context,
97 Iterable<Projection> projections,
98 Collection<PlaceholderNode> placeholderNodes ) {
99 final PathFactory pathFactory = context.getValueFactories().getPathFactory();
100 Map<Path, ProxyNode> proxyNodesByPath = new HashMap<Path, ProxyNode>();
101 Map<Path, PlaceholderNode> placeholdersByPath = new HashMap<Path, PlaceholderNode>();
102 for (Projection projection : projections) {
103 // Create for all of the top-level nodes ...
104 for (Path path : projection.getTopLevelPathsInRepository(pathFactory)) {
105 if (path.isRoot()) continue;
106 // Create ProxyNodes for each corresponding path-in-source ...
107 Location inRepository = Location.create(path);
108 ProxyNode previous = null;
109 for (Path pathInSource : projection.getPathsInSource(path, pathFactory)) {
110 Location inSource = Location.create(pathInSource);
111 ProxyNode proxy = new ProxyNode(projection, inSource, inRepository);
112 if (previous == null) {
113 previous = proxy;
114 proxyNodesByPath.put(path, proxy);
115 } else {
116 previous.add(proxy);
117 }
118 }
119 // Walk up the in-repository path to create the placeholder nodes ...
120 ProjectedNode child = previous;
121 while (!path.isRoot()) {
122 // Create a projected node for the parent of this path ...
123 Path parent = path.getParent();
124 PlaceholderNode parentPlaceholder = placeholdersByPath.get(parent);
125 if (parentPlaceholder == null) {
126 // Need to create the placeholder ...
127 Map<Name, Property> properties = Collections.emptyMap();
128 Location location = Location.create(parent, UUID.randomUUID());
129 parentPlaceholder = new PlaceholderNode(location, properties, new ArrayList<ProjectedNode>());
130 placeholdersByPath.put(parent, parentPlaceholder);
131 placeholderNodes.add(parentPlaceholder);
132 parentPlaceholder.children().add(child);
133 } else {
134 // The placeholder already exists, so make sure we're not adding it to this parent twice ...
135 List<ProjectedNode> children = parentPlaceholder.children();
136 if (!children.contains(child)) children.add(child);
137 }
138 child = parentPlaceholder;
139 path = parent;
140 }
141 }
142 }
143 }
144 }