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.List;
27 import net.jcip.annotations.Immutable;
28 import org.modeshape.graph.ExecutionContext;
29 import org.modeshape.graph.Location;
30 import org.modeshape.graph.property.Path;
31 import org.modeshape.graph.property.PathFactory;
32
33 /**
34 * A Projector for federated repository configurations that are a direct one-for-one mirror against a single source repository. In
35 * other words, the federated repository has a single projection with a single "/ => /" rule.
36 */
37 @Immutable
38 final class MirrorProjector implements Projector {
39
40 /**
41 * Attempt to create an instance of the {@link MirrorProjector} with the supplied projections using the supplied context.
42 *
43 * @param context the context; may not be null
44 * @param projections the projections in the federated repository; may not be null
45 * @return the mirror projector, or null if the projections didn't match the criteria for such a projector
46 */
47 static MirrorProjector with( ExecutionContext context,
48 List<Projection> projections ) {
49 assert projections != null;
50 assert context != null;
51 if (projections.size() != 1) return null;
52 Projection projection = projections.get(0);
53 assert projection != null;
54 if (projection.getRules().size() != 1) return null;
55 PathFactory pathFactory = context.getValueFactories().getPathFactory();
56 List<Path> topLevelPaths = projection.getRules().get(0).getTopLevelPathsInRepository(pathFactory);
57 if (topLevelPaths.size() != 1) return null;
58 if (!topLevelPaths.get(0).isRoot()) return null;
59 return new MirrorProjector(projection);
60 }
61
62 private final Projection projection;
63
64 private MirrorProjector( Projection projection ) {
65 this.projection = projection;
66 }
67
68 /**
69 * {@inheritDoc}
70 * <p>
71 * This implementation <i>always<i> returns a single {@link ProxyNode} for the location in the single projection.
72 * </p>
73 *
74 * @see org.modeshape.graph.connector.federation.Projector#project(ExecutionContext, Location, boolean)
75 */
76 public ProjectedNode project( ExecutionContext context,
77 Location location,
78 boolean requiresUpdate ) {
79 if (requiresUpdate && projection.isReadOnly()) return null;
80 return new ProxyNode(projection, location, location);
81 }
82
83 }