# BufferFactory.java

    /**
     *  Copyright (c) 2009, WSO2 Inc. (http://www.wso2.org) 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 org.apache.synapse.transport.passthru.util;

    import org.apache.http.nio.util.ByteBufferAllocator;
    import org.apache.http.nio.util.HeapByteBufferAllocator;

    import java.util.concurrent.locks.Lock;
    import java.util.concurrent.locks.ReentrantLock;

    public class BufferFactory {

        private volatile ControlledByteBuffer [] buffers;

        private volatile int marker = -1;

        private ByteBufferAllocator allocator = null;

        private Lock lock = new ReentrantLock();

        private int bufferSize = 1024 * 8;

        public BufferFactory(int bufferSize, ByteBufferAllocator allocator, int size) {
            this.bufferSize = bufferSize;
            if (allocator != null) {
                this.allocator = allocator;
            } else {
                this.allocator = new HeapByteBufferAllocator();
            }

            buffers = new ControlledByteBuffer[size];
        }

        public ControlledByteBuffer getBuffer() {

            if (marker == -1) {
                // System.out.println("allocating marker -1");
                return new ControlledByteBuffer(allocator.allocate(bufferSize));
            } else {
                try {
                    lock.lock();
                    if (marker >= 0) {
                        // System.out.println("Returning buffer");
                        ControlledByteBuffer controlledByteBuffer = buffers[marker];
                        controlledByteBuffer.clear();
                        controlledByteBuffer.forceSetInputMode();
                        buffers[marker] = null;
                        marker--;
                        return controlledByteBuffer;
                    }
                } finally {
                    lock.unlock();
                }
            }

            return new ControlledByteBuffer(allocator.allocate(bufferSize));
        }

        public void release(ControlledByteBuffer buffer) {
            lock.lock();
            try {
                if (marker < buffers.length - 1) {
                    buffer.clear();
                    buffer.forceSetInputMode();
                    buffers[++marker] = buffer;
                }
            } finally {
                lock.unlock();
            }
        }
    }