org.modeshape.jcr.BackupObserver Maven / Gradle / Ivy
/*
* ModeShape (http://www.modeshape.org)
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.modeshape.jcr;
import java.util.Collections;
import java.util.Queue;
import java.util.Set;
import java.util.concurrent.ConcurrentHashMap;
import org.modeshape.common.annotation.ThreadSafe;
import org.modeshape.jcr.cache.NodeKey;
import org.modeshape.jcr.cache.change.BinaryValueUnused;
import org.modeshape.jcr.cache.change.BinaryValueUsed;
import org.modeshape.jcr.cache.change.Change;
import org.modeshape.jcr.cache.change.ChangeSet;
import org.modeshape.jcr.cache.change.ChangeSetListener;
import org.modeshape.jcr.value.BinaryKey;
/**
* A {@link ChangeSetListener} that captures the changes being made in a repository, forwarding the node and property changes to
* the supplied queue, and capturing the set of binary keys that are marked as being used or unused.
*
* @see BackupService
*/
@ThreadSafe
public class BackupObserver implements ChangeSetListener {
private final Queue changedNodes;
private final Set usedBinaryKeys = Collections.newSetFromMap(new ConcurrentHashMap());
private final Set unusedBinaryKeys = Collections.newSetFromMap(new ConcurrentHashMap());
protected BackupObserver( Queue changedNodes ) {
this.changedNodes = changedNodes;
}
@Override
public void notify( ChangeSet changeSet ) {
if (changeSet == null) return;
// Add all of the changed nodes to the queue ...
changedNodes.addAll(changeSet.changedNodes());
// We only care about the binary changes; workspace changes will be handled by always writing out the
// repository's metadata document, and node changes are handled above ...
// Now process the binary changes ...
for (Change change : changeSet) {
// Look at property added/removed/changed events, and node add/removed/moved/renamed/reordered events ...
if (change instanceof BinaryValueUnused) {
BinaryValueUnused unused = (BinaryValueUnused)change;
BinaryKey key = unused.getKey();
if (usedBinaryKeys.contains(key)) {
// This change set had marked it as used, but now is unused again; removed it from the used.
usedBinaryKeys.remove(key);
break;
}
unusedBinaryKeys.add(key);
}
if (change instanceof BinaryValueUsed) {
BinaryValueUsed unused = (BinaryValueUsed)change;
BinaryKey key = unused.getKey();
if (unusedBinaryKeys.contains(key)) {
// This change set had marked it as used, but now is unused again; removed it from the used.
unusedBinaryKeys.remove(key);
break;
}
usedBinaryKeys.add(key);
}
}
}
/**
* Get the binary keys that have been marked as being unused during the time this observer was listening to the repository.
*
* @return the unused binary keys; never null, but possibly empty
*/
public Iterable getUnusedBinaryKeys() {
return unusedBinaryKeys;
}
/**
* Get the binary keys that have been marked as being used during the time this observer was listening to the repository.
*
* @return the used binary keys; never null, but possibly empty
*/
public Iterable getUsedBinaryKeys() {
return usedBinaryKeys;
}
}
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