package org.apache.maven.surefire.util.internal;

 /*

  * Licensed to the Apache Software Foundation (ASF) under one

  * or more contributor license agreements.  See the NOTICE file

  * distributed with this work for additional information

  * regarding copyright ownership.  The ASF 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.

  */

 /**

  * A producer/consumer queue that is optimized for *one* producer thread

  * and *one* consumer thread, and solely optimized for efficient inserts

  * by the producer, minimizing producer locking for hand-off to

  * a second consumer.

  *

  * TwoThreadBlockingQueue insert 5000000 elements in  = 52

  * FunkyTwoThreadBlockingQueue insert 5000000 elements in  = 42

  * TwoThreadBlockingQueue produced and taken 5000000 elements in  = 104

  * LinkedBlockingQueue insert 5000000 elements in  = 1815

  * LinkedBlockingDeque insert 5000000 elements in  = 113

  * ArrayList insert 5000000 elements in  = 18

  * LinkedList insert 5000000 elements in  = 334

  *

  * @author Kristian Rosenvold

  */

 public class FunkyTwoThreadBlockingQueue implements BlockingQueue

 {

     final int chunkSize = 100;

     private Chunk takeChunk = new Chunk();

     private int takePos = 0;

     private Chunk insertChunk = takeChunk;

     private int insertPos = 0;

     private volatile boolean memoryModelGuard;

     public void put( Object object )

     {

         insertChunk.elements[insertPos] = object;

         if ( ++insertPos == chunkSize)

         {

             Chunk newChunk = new Chunk();

             insertChunk.next = newChunk;

             insertChunk = newChunk;

             insertPos = 0;

         }

         memoryModelGuard = true;

     }

     public void add( Object object )

     {

         put(  object );

     }

     public Object take()

         throws InterruptedException

     {

         if ( takePos >= chunkSize )

         {

             takeChunk = takeChunk.next;

             takePos = 0;

         }

         boolean fud = memoryModelGuard;

         Object next = takeChunk.elements[takePos];

         while ( next == null )

         {

             Thread.sleep( 1 );

             fud = memoryModelGuard;

             next = takeChunk.elements[takePos];

         }

         takePos++;

         return next;

     }

     final class Chunk

     {

         final Object[] elements = new Object[chunkSize];

         volatile Chunk next;

     }

 }