Java tutorial
/* * JaLingo, http://jalingo.sourceforge.net/ * * Copyright (c) 2002-2006 Oleksandr Shyshko * * 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 */ package ja.lingo.engine.util; import ja.centre.util.assertions.Arguments; import ja.centre.util.io.Files; import org.apache.commons.logging.Log; import org.apache.commons.logging.LogFactory; import java.io.File; import java.io.FileInputStream; import java.io.FileOutputStream; import java.io.IOException; import java.nio.ByteBuffer; import java.nio.channels.FileChannel; public class EngineFiles { private static final Log LOG = LogFactory.getLog(EngineFiles.class); private static final int COPY_BUFFER_SIZE = 32768; public static long tempFileSuffixCounter = System.currentTimeMillis(); // TODO not very robust generator private EngineFiles() { } public static String calculateInWorking(String fileName) { Arguments.assertNotNull("fileName", fileName); return calculateWorking() + File.separator + fileName; } public static String calculateWorking() { return Files.calculateFileNameInUserHome(".jalingo"); } public static String createTemp(String prefix) throws IOException { return createTempFile(prefix).getAbsolutePath(); } public static File createTempFile(String prefix) throws IOException { String tempDir = calculateTemp(); Files.ensureDirectoryExists(tempDir); String fileName = tempDir + File.separator + prefix + "." + tempFileSuffixCounter++; File file = new File(fileName).getAbsoluteFile(); file.deleteOnExit(); return file; } private static String calculateTemp() { return calculateInWorking("temp"); } public static void appendFileAndDelete(String fileName, FileOutputStream fos) throws IOException { appendFile(fileName, fos, false); } public static void appendFileLengthWithContentAndDelete(String fileName, FileOutputStream fos) throws IOException { appendFile(fileName, fos, true); } private static void appendFile(String fileName, FileOutputStream fos, boolean prependWithLength) throws IOException { FileInputStream fis = new FileInputStream(fileName); FileChannel fic = fis.getChannel(); FileChannel foc = fos.getChannel(); ByteBuffer buffer = ByteBuffer.allocate(COPY_BUFFER_SIZE); // put header: length (1 int = 4 bytes) if (prependWithLength) { buffer.putInt((int) new File(fileName).length()); } // put body do { buffer.flip(); foc.write(buffer); buffer.clear(); } while (fic.read(buffer) != -1); fic.close(); // NOTE: do not close 'foc' Files.delete(fileName); } public static void cleanTemp() { String temp = calculateTemp(); LOG.info("Cleaning temp directory \"" + temp + "\""); try { Files.deleteRecusrsively(temp); } catch (IOException e) { LOG.warn("Could not clean temp directory \"" + temp + "\""); } } }