/*

 * Copyright (c) 2005, 2017, Oracle and/or its affiliates. All rights reserved.

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.  Oracle designates this

 * particular file as subject to the "Classpath" exception as provided

 * by Oracle in the LICENSE file that accompanied this code.

 *

 * This code is distributed in the hope that it will be useful, but WITHOUT

 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

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package com.sun.xml.internal.stream.util;

import java.lang.ref.*;

/**

 * This is a Singleton class that allows you to allocate buffer that

 * are stored in ThreadLocal. This class stores 3 types of char

 * buffers - small (< 128 bytes), medium (<2K) and large (> 2K) as

 * well as three byte buffers - small, medium and large.

 * The local storage is activated on the return of the buffer.

 * The buffer returns null if it is already allocated.

 *

 * @author Binu John

 * @author Santiago PericasGeertsen

 */

public class ThreadLocalBufferAllocator {

   private static ThreadLocal<SoftReference<BufferAllocator>> tlba = new ThreadLocal<>();

   public static BufferAllocator getBufferAllocator() {

        SoftReference<BufferAllocator> bAllocatorRef = tlba.get();

        if (bAllocatorRef == null || bAllocatorRef.get() == null) {

            bAllocatorRef = new SoftReference<>(new BufferAllocator());

            tlba.set(bAllocatorRef);

        }

        return bAllocatorRef.get();

   }

}