/*
* 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.cache.document;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.util.concurrent.locks.Lock;
import java.util.concurrent.locks.ReadWriteLock;
import java.util.concurrent.locks.ReentrantReadWriteLock;
import org.modeshape.common.annotation.ThreadSafe;
import org.modeshape.common.collection.LinkedListMultimap;
import org.modeshape.common.collection.ListMultimap;
import org.modeshape.jcr.cache.ChildReference;
import org.modeshape.jcr.cache.NodeKey;
import org.modeshape.jcr.value.Name;
/**
*
*/
@ThreadSafe
public class MutableChildReferences extends AbstractChildReferences {
private final ReadWriteLock lock = new ReentrantReadWriteLock();
private final ListMultimap<Name, ChildReference> childReferences;
private final Map<NodeKey, ChildReference> childReferencesByKey;
protected MutableChildReferences() {
this.childReferences = LinkedListMultimap.create();
this.childReferencesByKey = new HashMap<NodeKey, ChildReference>();
}
@Override
public long size() {
Lock lock = this.lock.readLock();
try {
lock.lock();
return childReferencesByKey.size();
} finally {
lock.unlock();
}
}
@Override
public int getChildCount( Name name ) {
Lock lock = this.lock.readLock();
try {
lock.lock();
return childReferences.get(name).size();
} finally {
lock.unlock();
}
}
@Override
public ChildReference getChild( Name name,
int snsIndex,
Context context ) {
if (context == null) context = new SingleNameContext();
Lock lock = this.lock.readLock();
try {
lock.lock();
List<ChildReference> childrenWithSameName = this.childReferences.get(name);
if (childrenWithSameName.isEmpty()) {
// This segment contains no nodes with the supplied name ...
return null;
}
// We have at least one SNS in this list ...
for (ChildReference childWithSameName : childrenWithSameName) {
int index = context.consume(childWithSameName.getName(), childWithSameName.getKey());
if (index == snsIndex) return childWithSameName.with(index);
}
return null;
} finally {
lock.unlock();
}
}
@Override
public ChildReference getChild( NodeKey key,
Context context ) {
if (context == null) context = new SingleNameContext();
Lock lock = this.lock.readLock();
try {
lock.lock();
ChildReference ref = childReferencesByKey.get(key);
if (ref != null) {
// It's in this list but there are no changes ...
List<ChildReference> childrenWithSameName = this.childReferences.get(ref.getName());
assert childrenWithSameName != null;
assert childrenWithSameName.size() != 0;
// Consume the child references until we find the reference ...
for (ChildReference child : childrenWithSameName) {
int index = context.consume(child.getName(), child.getKey());
if (key.equals(child.getKey())) return child.with(index);
}
}
return ref;
} finally {
lock.unlock();
}
}
@Override
public ChildReference getChild( NodeKey key ) {
return getChild(key, new BasicContext());
}
@Override
public boolean hasChild( NodeKey key ) {
Lock lock = this.lock.readLock();
try {
lock.lock();
return childReferencesByKey.containsKey(key);
} finally {
lock.unlock();
}
}
@Override
public Iterator<ChildReference> iterator() {
Lock lock = this.lock.readLock();
try {
lock.lock();
// TODO: should this be a copy?
return childReferences.values().iterator();
} finally {
lock.unlock();
}
}
@Override
public Iterator<ChildReference> iterator( Name name ) {
Lock lock = this.lock.readLock();
try {
lock.lock();
// TODO: should this be a copy?
return childReferences.get(name).iterator();
} finally {
lock.unlock();
}
}
@Override
public Iterator<NodeKey> getAllKeys() {
Lock lock = this.lock.readLock();
try {
lock.lock();
return new HashSet<NodeKey>(childReferencesByKey.keySet()).iterator();
} finally {
lock.unlock();
}
}
public void append( NodeKey key,
Name name ) {
ChildReference reference = new ChildReference(key, name, 1);
Lock lock = this.lock.writeLock();
try {
lock.lock();
ChildReference old = this.childReferencesByKey.put(reference.getKey(), reference);
if (old != null && old.getName().equals(name)) {
// We already have this key/name pair, so we don't need to add it again ...
return;
}
// We've not seen this node key yet, so it is okay. In fact, we should not see any
// node key more than once, since that is clearly an unexpected condition (as a child
// may not appear more than once in its parent's list of child nodes). See MODE-2120.
this.childReferences.put(reference.getName(), reference);
} finally {
lock.unlock();
}
}
public void append( Iterable<ChildReference> references ) {
Lock lock = this.lock.writeLock();
try {
lock.lock();
for (ChildReference reference : references) {
reference = reference.with(1);
ChildReference old = this.childReferencesByKey.put(reference.getKey(), reference);
if (old != null && old.getName().equals(reference.getName())) {
// We already have this key/name pair, so we don't need to add it again ...
continue;
}
// We've not seen this node key yet, so it is okay. In fact, we should not see any
// node key more than once, since that is clearly an unexpected condition (as a child
// may not appear more than once in its parent's list of child nodes). See MODE-2120.
this.childReferences.put(reference.getName(), reference);
}
} finally {
lock.unlock();
}
}
public ChildReference remove( NodeKey key ) {
Lock lock = this.lock.writeLock();
try {
lock.lock();
ChildReference existing = this.childReferencesByKey.remove(key);
if (existing != null) {
this.childReferences.remove(existing.getName(), existing);
}
return existing;
} finally {
lock.unlock();
}
}
@Override
public StringBuilder toString( StringBuilder sb ) {
sb.append("appended: ");
Lock lock = this.lock.readLock();
try {
lock.lock();
Iterator<ChildReference> iter = childReferences.values().iterator();
if (iter.hasNext()) {
sb.append(iter.next());
while (iter.hasNext()) {
sb.append(", ");
sb.append(iter.next());
}
}
} finally {
lock.unlock();
}
return sb;
}
}