Here you can find the source of mapByteBuffer(File cachedFile, int cacheFileSize)
public static ByteBuffer mapByteBuffer(File cachedFile, int cacheFileSize) throws IOException
//package com.java2s; /*/*from ww w. ja va 2 s . co m*/ * Copyright (C) 2010 Stephen Tigner * * This program is free software; you can redistribute it and/or * modify it under the terms of the GNU General Public License as * published by the Free Software Foundation; either version 2 of the * License, or (at your option) any later version. * * This program 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 for more details. * * You should have received a copy of the GNU General Public License * along with this program; if not, write to the Free Software * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA * 02111-1307, USA. */ import java.io.*; import java.nio.ByteBuffer; import java.nio.channels.FileChannel; public class Main { public static ByteBuffer mapByteBuffer(File cachedFile, int cacheFileSize) throws IOException { ByteBuffer byteBufferPositions = null; if (cacheFileSize > 1024) // don't cache tiny files try { if (cachedFile.canRead() && cachedFile.length() == cacheFileSize) { RandomAccessFile raf = new RandomAccessFile(cachedFile, "r"); byteBufferPositions = raf.getChannel().map(FileChannel.MapMode.READ_ONLY, 0, cacheFileSize); return byteBufferPositions; } if (cachedFile.exists()) cachedFile.delete(); cachedFile.getParentFile().mkdirs(); cachedFile.createNewFile(); if (cachedFile.canWrite()) { RandomAccessFile raf = new RandomAccessFile(cachedFile, "rw"); byteBufferPositions = raf.getChannel().map(FileChannel.MapMode.READ_WRITE, 0, cacheFileSize); return byteBufferPositions; } } catch (Exception e) { } byteBufferPositions = ByteBuffer.allocate(cacheFileSize); //int[number_of_statesl]; return byteBufferPositions; } }