001    /*
002     * Sonar, open source software quality management tool.
003     * Copyright (C) 2008-2011 SonarSource
004     * mailto:contact AT sonarsource DOT com
005     *
006     * Sonar is free software; you can redistribute it and/or
007     * modify it under the terms of the GNU Lesser General Public
008     * License as published by the Free Software Foundation; either
009     * version 3 of the License, or (at your option) any later version.
010     *
011     * Sonar is distributed in the hope that it will be useful,
012     * but WITHOUT ANY WARRANTY; without even the implied warranty of
013     * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
014     * Lesser General Public License for more details.
015     *
016     * You should have received a copy of the GNU Lesser General Public
017     * License along with Sonar; if not, write to the Free Software
018     * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02
019     */
020    package org.sonar.api.utils;
021    
022    import java.io.File;
023    import java.io.IOException;
024    
025    public final class TempFileUtils {
026    
027      private TempFileUtils() {
028        // only static methods
029      }
030    
031      /**
032       * Create a temporary directory. This directory is NOT deleted when the JVM stops, because using File#deleteOnExit()
033       * is evil (google "deleteonExit evil"). Copied from http://stackoverflow.com/questions/617414/create-a-temporary-directory-in-java :
034       * <ol>
035       * <li>deleteOnExit() only deletes for normal JVM shutdowns, not crashes or killing the JVM process</li>
036       * <li>deleteOnExit() only deletes on JVM shutdown - not good for long running server processes because 3 :</li>
037       * <li>The most evil of all - deleteOnExit() consumes memory for each temp file entry. If your process is running for months,
038       * or creates a lot of temp files in a short time, you consume memory and never release it until the JVM
039       * shuts down.</li>
040       * </ol>
041       */
042      public static File createTempDirectory() throws IOException {
043        return createTempDirectory("temp");
044      }
045    
046      public static File createTempDirectory(String prefix) throws IOException {
047        final File temp = File.createTempFile(prefix, Long.toString(System.nanoTime()));
048        if (!temp.delete()) {
049          throw new IOException("Could not delete temp file: " + temp.getAbsolutePath());
050        }
051    
052        if (!temp.mkdir()) {
053          throw new IOException("Could not create temp directory: " + temp.getAbsolutePath());
054        }
055        return temp;
056      }
057    }