com.hazelcast.map.writebehind.WriteBehindQueues Maven / Gradle / Ivy
/*
* Copyright (c) 2008-2013, Hazelcast, Inc. All Rights Reserved.
*
* 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 com.hazelcast.map.writebehind;
import java.util.Collection;
import java.util.Collections;
import java.util.List;
/**
* A class providing static factory methods that create write behind queues.
*/
public final class WriteBehindQueues {
private WriteBehindQueues() {
}
public static WriteBehindQueue createArrayWriteBehindQueue() {
return new ArrayWriteBehindQueue();
}
public static WriteBehindQueue createBoundedArrayWriteBehindQueue() {
return new BoundedArrayWriteBehindQueue();
}
public static WriteBehindQueue createDefaultWriteBehindQueue(boolean isWriteBehindEnabled) {
return isWriteBehindEnabled
? (WriteBehindQueue) createSafeWriteBehindQueue(createBoundedArrayWriteBehindQueue())
: (WriteBehindQueue) emptyWriteBehindQueue();
}
public static WriteBehindQueue emptyWriteBehindQueue() {
return (WriteBehindQueue) EmptyWriteBehindQueueHolder.EMPTY_WRITE_BEHIND_QUEUE;
}
public static WriteBehindQueue createSafeWriteBehindQueue(WriteBehindQueue queue) {
return new SynchronizedWriteBehindQueue(queue);
}
/**
* Holder provides lazy initialization for singleton instance.
*/
private static final class EmptyWriteBehindQueueHolder {
/**
* Neutral null empty queue.
*/
private static final WriteBehindQueue EMPTY_WRITE_BEHIND_QUEUE = new EmptyWriteBehindQueue();
}
/**
* Empty write behind queue provides neutral null behaviour.
*/
private static final class EmptyWriteBehindQueue implements WriteBehindQueue {
@Override
public boolean offer(Object o) {
return false;
}
@Override
public void removeFirst() {
}
@Override
public Object get(int index) {
throw new IndexOutOfBoundsException("Index: " + index);
}
@Override
public boolean contains(Object o) {
return false;
}
@Override
public int size() {
return 0;
}
@Override
public void clear() {
}
@Override
public WriteBehindQueue getSnapShot() {
return WriteBehindQueues.emptyWriteBehindQueue();
}
@Override
public void addFront(Collection collection) {
}
@Override
public void addEnd(Collection collection) {
}
@Override
public List fetchAndRemoveAll() {
return Collections.emptyList();
}
@Override
public boolean isEnabled() {
return false;
}
@Override
public List asList() {
return Collections.emptyList();
}
@Override
public void shrink() {
}
}
}