/*
* JBoss DNA (http://www.jboss.org/dna)
* See the COPYRIGHT.txt file distributed with this work for information
* regarding copyright ownership. Some portions may be licensed
* to Red Hat, Inc. under one or more contributor license agreements.
* See the AUTHORS.txt file in the distribution for a full listing of
* individual contributors.
*
* JBoss DNA is free software. Unless otherwise indicated, all code in JBoss DNA
* is licensed to you under the terms of the GNU Lesser General Public License as
* published by the Free Software Foundation; either version 2.1 of
* the License, or (at your option) any later version.
*
* JBoss DNA is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this software; if not, write to the Free
* Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
* 02110-1301 USA, or see the FSF site: http://www.fsf.org.
*/
package org.jboss.dna.graph.connector.federation;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Collections;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.UUID;
import net.jcip.annotations.Immutable;
import org.jboss.dna.graph.ExecutionContext;
import org.jboss.dna.graph.Location;
import org.jboss.dna.graph.property.Name;
import org.jboss.dna.graph.property.Path;
import org.jboss.dna.graph.property.PathFactory;
import org.jboss.dna.graph.property.Property;
/**
* A Projector for federated repository configurations that are an offset, direct one-for-one mirror against a single source
* repository that is projected below the federated root. In other words, the federated repository has a single projection with a
* single "/something/below/root => /" rule.
*/
@Immutable
abstract class ProjectorWithPlaceholders implements Projector {
private Map<Path, PlaceholderNode> placeholderNodesByPath;
private Map<UUID, PlaceholderNode> placeholderNodesByUuid;
ProjectorWithPlaceholders( ExecutionContext context,
List<Projection> projections ) {
placeholderNodesByPath = new HashMap<Path, PlaceholderNode>();
placeholderNodesByUuid = new HashMap<UUID, PlaceholderNode>();
// Use the execution context of the source to load the projected nodes ...
Collection<PlaceholderNode> placeholders = new ArrayList<PlaceholderNode>();
loadPlaceholderNodes(context, projections, placeholders);
for (PlaceholderNode placeholder : placeholders) {
placeholderNodesByPath.put(placeholder.location().getPath(), placeholder);
placeholderNodesByUuid.put(placeholder.location().getUuid(), placeholder);
}
}
/**
* Determine whether the specified location is a placeholder node.
*
* @param location the location of the node; may not be null
* @return the placeholder node, or null if the supplied location does not designate a placeholder node
*/
public PlaceholderNode isPlaceholder( Location location ) {
Path path = location.getPath();
if (path != null) {
return placeholderNodesByPath.get(path);
}
UUID uuid = location.getUuid();
if (uuid != null) {
return placeholderNodesByUuid.get(uuid);
}
return null;
}
/**
* Load the placeholder nodes for this repository. This method does not modify any state of this instance, but instead
* populates the supplied map.
* <p>
* A placeholder is created for each node above the projections' {@link Projection#getTopLevelPathsInRepository(PathFactory)
* top-level paths} in the federated repository. Thus, the projected node immediately above a top-level path will contain the
* top-level path as a child.
* </p>
*
* @param context the context in which the placeholder nodes should be materialized; may not be null
* @param projections the projections; may not be null
* @param placeholderNodes the collection into which should be placed the materialized placeholders
*/
protected static void loadPlaceholderNodes( ExecutionContext context,
Iterable<Projection> projections,
Collection<PlaceholderNode> placeholderNodes ) {
final PathFactory pathFactory = context.getValueFactories().getPathFactory();
Map<Path, ProxyNode> proxyNodesByPath = new HashMap<Path, ProxyNode>();
Map<Path, PlaceholderNode> placeholdersByPath = new HashMap<Path, PlaceholderNode>();
for (Projection projection : projections) {
// Create for all of the top-level nodes ...
for (Path path : projection.getTopLevelPathsInRepository(pathFactory)) {
if (path.isRoot()) continue;
// Create ProxyNodes for each corresponding path-in-source ...
Location inRepository = Location.create(path);
ProxyNode previous = null;
for (Path pathInSource : projection.getPathsInSource(path, pathFactory)) {
Location inSource = Location.create(pathInSource);
ProxyNode proxy = new ProxyNode(projection, inSource, inRepository);
if (previous == null) {
previous = proxy;
proxyNodesByPath.put(path, proxy);
} else {
previous.add(proxy);
}
}
// Walk up the in-repository path to create the placeholder nodes ...
ProjectedNode child = previous;
while (!path.isRoot()) {
// Create a projected node for the parent of this path ...
Path parent = path.getParent();
PlaceholderNode parentPlaceholder = placeholdersByPath.get(parent);
if (parentPlaceholder == null) {
// Need to create the placeholder ...
Map<Name, Property> properties = Collections.emptyMap();
Location location = Location.create(parent, UUID.randomUUID());
parentPlaceholder = new PlaceholderNode(location, properties, new ArrayList<ProjectedNode>());
placeholdersByPath.put(parent, parentPlaceholder);
placeholderNodes.add(parentPlaceholder);
parentPlaceholder.children().add(child);
} else {
// The placeholder already exists, so make sure we're not adding it to this parent twice ...
List<ProjectedNode> children = parentPlaceholder.children();
if (!children.contains(child)) children.add(child);
}
child = parentPlaceholder;
path = parent;
}
}
}
}
}