Java ByteBuffer Capacity borrowByteBuffer(final int capacity)

Description

borrow Byte Buffer

License

Open Source License

Declaration

public static final ByteBuffer borrowByteBuffer(final int capacity) 

Method Source Code

//package com.java2s;
/*  Copyright (c) 2010 Xiaoyun Zhu
 * /*from w ww. j  a  va2 s.c  om*/
 *  Permission is hereby granted, free of charge, to any person obtaining a copy  
 *  of this software and associated documentation files (the "Software"), to deal  
 *  in the Software without restriction, including without limitation the rights  
 *  to use, copy, modify, merge, publish, distribute, sublicense, and/or sell  
 *  copies of the Software, and to permit persons to whom the Software is  
 *  furnished to do so, subject to the following conditions:
 *  
 *  The above copyright notice and this permission notice shall be included in  
 *  all copies or substantial portions of the Software.
 *  
 *  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR  
 *  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,  
 *  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE  
 *  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER  
 *  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,  
 *  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN  
 *  THE SOFTWARE.  
 */

import java.nio.ByteBuffer;

import java.util.ArrayList;

import java.util.List;

public class Main {
    private static final List<ByteBuffer> byteBuffersPoolLarge = new ArrayList<ByteBuffer>();
    private static final List<ByteBuffer> byteBuffersPoolMedium = new ArrayList<ByteBuffer>();
    private static final List<ByteBuffer> byteBuffersPoolNormal = new ArrayList<ByteBuffer>();
    private static final List<ByteBuffer> byteBuffersPoolSmall = new ArrayList<ByteBuffer>();
    private static final List<ByteBuffer> byteBuffersPoolVeryLarge = new ArrayList<ByteBuffer>();
    public static final int MAX_LINE_BYTES_LARGE = 1024 * 64;
    public static final int MAX_LINE_BYTES_MEDIUM = 1024 * 32;
    public static final int MAX_LINE_BYTES_NORMAL = 1024 * 4;
    public static final int MAX_LINE_BYTES_SMALL = 1024;
    public static final int MAX_LINE_BYTES_VERY_LARGE = 1024 * 280;

    public static final ByteBuffer borrowByteBuffer(final int capacity) {
        if (capacity >= MAX_LINE_BYTES_VERY_LARGE) {
            return ByteBuffer.allocate(capacity);
        } else if (capacity >= MAX_LINE_BYTES_LARGE) {
            return borrowByteBufferVeryLarge();
        } else if (capacity >= MAX_LINE_BYTES_MEDIUM) {
            return borrowByteBufferLarge();
        } else if (capacity >= MAX_LINE_BYTES_NORMAL) {
            return borrowByteBufferMedium();
        } else if (capacity >= MAX_LINE_BYTES_SMALL) {
            return borrowByteBufferNormal();
        } else {
            return borrowByteBufferSmall();
        }
    }

    public final static ByteBuffer borrowByteBufferVeryLarge() {
        if (byteBuffersPoolVeryLarge.isEmpty()) {
            return ByteBuffer.allocate(MAX_LINE_BYTES_VERY_LARGE);
        } else {
            return byteBuffersPoolVeryLarge.remove(0);
        }
    }

    public final static ByteBuffer borrowByteBufferLarge() {
        if (byteBuffersPoolLarge.isEmpty()) {
            return ByteBuffer.allocate(MAX_LINE_BYTES_LARGE);
        } else {
            return byteBuffersPoolLarge.remove(0);
        }
    }

    public final static ByteBuffer borrowByteBufferMedium() {
        if (byteBuffersPoolMedium.isEmpty()) {
            return ByteBuffer.allocate(MAX_LINE_BYTES_MEDIUM);
        } else {
            return byteBuffersPoolMedium.remove(0);
        }
    }

    public final static ByteBuffer borrowByteBufferNormal() {
        if (byteBuffersPoolNormal.isEmpty()) {
            return ByteBuffer.allocate(MAX_LINE_BYTES_NORMAL);
        } else {
            return byteBuffersPoolNormal.remove(0);
        }
    }

    public final static ByteBuffer borrowByteBufferSmall() {
        if (byteBuffersPoolSmall.isEmpty()) {
            return ByteBuffer.allocate(MAX_LINE_BYTES_SMALL);
        } else {
            return byteBuffersPoolSmall.remove(0);
        }
    }

    /**
     * position is 0 and limit = capacity.
     * 
     * @param bb
     * @return
     */
    public final static boolean isEmpty(final ByteBuffer bb) {
        return (bb.position() == 0 && bb.limit() == bb.capacity()) || bb.limit() == 0;
    }
}

Related

1. ensureCapacity(ByteBuffer buff, int len)
2. ensureCapacity(ByteBuffer buffer, int capacity)
3. ensureCapacity(ByteBuffer existingBuffer, int newLength)
4. ensureCapacity(ByteBuffer original, int newCapacity)