/*
* JBoss, Home of Professional Open Source.
* Copyright 2008, Red Hat Middleware LLC, and individual contributors
* as indicated by the @author tags. See the copyright.txt file in the
* distribution for a full listing of individual contributors.
*
* This is free software; you can redistribute it and/or modify it
* 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.
*
* This software 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.connector.federation.merge.strategy;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.util.UUID;
import net.jcip.annotations.ThreadSafe;
import org.jboss.dna.connector.federation.contribution.Contribution;
import org.jboss.dna.connector.federation.merge.FederatedNode;
import org.jboss.dna.connector.federation.merge.MergePlan;
import org.jboss.dna.graph.DnaLexicon;
import org.jboss.dna.graph.ExecutionContext;
import org.jboss.dna.graph.properties.Name;
import org.jboss.dna.graph.properties.Property;
import org.jboss.dna.graph.properties.UuidFactory;
import org.jboss.dna.graph.properties.ValueFormatException;
import org.jboss.dna.graph.properties.Path.Segment;
/**
* A merge strategy that is optimized for merging when there is a single contribution.
*
* @author Randall Hauch
*/
@ThreadSafe
public class OneContributionMergeStrategy implements MergeStrategy {
public static final boolean DEFAULT_REUSE_UUID_FROM_CONTRIBUTION = true;
private boolean useUuidFromContribution = DEFAULT_REUSE_UUID_FROM_CONTRIBUTION;
/**
* @return reuseUuidFromContribution
*/
public boolean isContributionUuidUsedForFederatedNode() {
return useUuidFromContribution;
}
/**
* @param useUuidFromContribution Sets useUuidFromContribution to the specified value.
*/
public void setContributionUuidUsedForFederatedNode( boolean useUuidFromContribution ) {
this.useUuidFromContribution = useUuidFromContribution;
}
/**
* {@inheritDoc}
* <p>
* This method only uses the one and only one non-null {@link Contribution} in the <code>contributions</code>.
* </p>
*
* @see org.jboss.dna.connector.federation.merge.strategy.MergeStrategy#merge(org.jboss.dna.connector.federation.merge.FederatedNode,
* java.util.List, org.jboss.dna.graph.ExecutionContext)
*/
public void merge( FederatedNode federatedNode,
List<Contribution> contributions,
ExecutionContext context ) {
assert federatedNode != null;
assert context != null;
assert contributions != null;
assert contributions.size() > 0;
Contribution contribution = contributions.get(0);
assert contribution != null;
final boolean findUuid = isContributionUuidUsedForFederatedNode();
// Copy the children ...
List<Segment> children = federatedNode.getChildren();
children.clear();
Iterator<Segment> childIterator = contribution.getChildren();
while (childIterator.hasNext()) {
Segment child = childIterator.next();
children.add(child);
}
// Copy the properties ...
Map<Name, Property> properties = federatedNode.getPropertiesByName();
properties.clear();
UUID uuid = null;
UuidFactory uuidFactory = null;
Iterator<Property> propertyIterator = contribution.getProperties();
while (propertyIterator.hasNext()) {
Property property = propertyIterator.next();
if (findUuid && uuid == null && property.getName().getLocalName().equals("uuid")) {
if (property.isSingle()) {
if (uuidFactory == null) uuidFactory = context.getValueFactories().getUuidFactory();
try {
uuid = uuidFactory.create(property.getValues().next());
} catch (ValueFormatException e) {
// Ignore conversion exceptions
}
}
} else {
properties.put(property.getName(), property);
}
}
// If we found a single "uuid" property whose value is a valid UUID ..
if (uuid != null) {
// then set the UUID on the federated node ...
federatedNode.setUuid(uuid);
}
// Set the UUID as a property ...
Property uuidProperty = context.getPropertyFactory().create(DnaLexicon.UUID, federatedNode.getUuid());
properties.put(uuidProperty.getName(), uuidProperty);
// Assign the merge plan ...
MergePlan mergePlan = MergePlan.create(contributions);
federatedNode.setMergePlan(mergePlan);
}
}