apache-poi/src/java/org/apache/poi/util/TempFile.java

/* ====================================================================
   Copyright 2002-2004   Apache Software Foundation

   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.poi.util;

import java.io.File;
import java.io.IOException;
import java.util.Random;

/**
 * Interface for creating temporary files.  Collects them all into one directory.
 *
 * @author Glen Stampoultzis
 */
public class TempFile
{
    static File dir;
    static Random rnd = new Random();

    /**
     * Creates a temporary file.  Files are collected into one directory and by default are
     * deleted on exit from the VM.  Files can be kept by defining the system property
     * <code>poi.keep.tmp.files</code>.
     * <p>
     * Dont forget to close all files or it might not be possible to delete them.
     */
    public static File createTempFile(String prefix, String suffix) throws IOException
    {
        if (dir == null)
        {
            dir = new File(System.getProperty("java.io.tmpdir"), "poifiles");
            dir.mkdir();
            if (System.getProperty("poi.keep.tmp.files") == null)
                dir.deleteOnExit();
        }

        File newFile = new File(dir, prefix + rnd.nextInt() + suffix);
        if (System.getProperty("poi.keep.tmp.files") == null)
            newFile.deleteOnExit();
        return newFile;
    }



}