/*
 * Licensed to ElasticSearch and Shay Banon under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership. ElasticSearch licenses this
 * file to you 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.elasticsearch.common.util.concurrent;

import jsr166y.LinkedTransferQueue;
import org.elasticsearch.common.collect.MapBackedSet;

import java.util.Queue;
import java.util.Set;
import java.util.concurrent.BlockingQueue;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.ConcurrentMap;

/**
 *
 */
public abstract class ConcurrentCollections {

    private final static boolean useNonBlockingMap = Boolean.parseBoolean(System.getProperty("elasticsearch.useNonBlockingMap", "false"));

    public static <K, V> ConcurrentMap<K, V> newConcurrentMap() {
//        if (useNonBlockingMap) {
//            return new NonBlockingHashMap<K, V>();
//        }
        return new ConcurrentHashMap<K, V>();
    }

    public static <V> ConcurrentMapLong<V> newConcurrentMapLong() {
//        if (useNonBlockingMap) {
//            return new NonBlockingHashMapLong<V>();
//        }
        return new ConcurrentHashMapLong<V>();
    }

    public static <V> Set<V> newConcurrentSet() {
//        if (useNonBlockingMap) {
//            return new NonBlockingHashSet<V>();
//        }
        return new MapBackedSet<V>(new ConcurrentHashMap<V, Boolean>());
    }

    public static <T> Queue<T> newQueue() {
        return new LinkedTransferQueue<T>();
    }

    public static <T> BlockingQueue<T> newBlockingQueue() {
        return new LinkedTransferQueue<T>();
    }

    private ConcurrentCollections() {

    }
}

@@ -1078,16 +1078,67 @@
 ashMap;%0A
+import java.util.concurrent.ConcurrentLinkedQueue;%0A
 import j
@@ -1172,16 +1172,16 @@
 entMap;%0A
-
 %0A/**%0A *%0A
@@ -1330,38 +1330,165 @@
 y(%22e
-lasticsearch.useNonBlockingMap
+s.useNonBlockingMap%22, %22false%22));%0A    private final static boolean useLinkedTransferQueue = Boolean.parseBoolean(System.getProperty(%22es.useLinkedTransferQueue
 %22, %22
@@ -2223,33 +2223,132 @@
     
-return new LinkedTransfer
+if (useLinkedTransferQueue) %7B%0A            return new LinkedTransferQueue%3CT%3E();%0A        %7D%0A        return new ConcurrentLinked
 Queu

allow to set which queue implementation to use expert setting, but still would be great to be able to control it