FileHelper.java Source code

Introduction

Here is the source code for FileHelper.java

Source

/*
 * Static File routines.
 * Copyright (C) 2002 Stephen Ostermiller
 * http://ostermiller.org/contact.pl?regarding=Java+Utilities
 *
 * 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.
 *
 * See COPYING.TXT for details.
 */

import java.io.*;
import java.text.MessageFormat;
import java.util.ResourceBundle;
import java.util.Locale;

/**
 * Utilities for File manipulation.
 * More information about this class is available from <a target="_top" href=
 * "http://ostermiller.org/utils/FileHelper.html">ostermiller.org</a>.
 *
 * @author Stephen Ostermiller http://ostermiller.org/contact.pl?regarding=Java+Utilities
 * @since ostermillerutils 1.00.00
 */
public class FileHelper {

    /**
     * Locale specific strings displayed to the user.
     *
     * @since ostermillerutils 1.00.00
     */
    protected static ResourceBundle labels = ResourceBundle.getBundle("com.Ostermiller.util.FileHelper",
            Locale.getDefault());

    /**
     * Move a file from one location to another.  An attempt is made to rename
     * the file and if that fails, the file is copied and the old file deleted.
     *
     * If the destination file already exists, an exception will be thrown.
     *
     * @param from file which should be moved.
     * @param to desired destination of the file.
     * @throws IOException if an error occurs.
     *
     * @since ostermillerutils 1.00.00
     */
    public static void move(File from, File to) throws IOException {
        move(from, to, false);
    }

    /**
     * Move a file from one location to another.  An attempt is made to rename
     * the file and if that fails, the file is copied and the old file deleted.
     *
     * @param from file which should be moved.
     * @param to desired destination of the file.
     * @param overwrite If false, an exception will be thrown rather than overwrite a file.
     * @throws IOException if an error occurs.
     *
     * @since ostermillerutils 1.00.00
     */
    public static void move(File from, File to, boolean overwrite) throws IOException {
        if (to.exists()) {
            if (overwrite) {
                if (!to.delete()) {
                    throw new IOException(MessageFormat.format(labels.getString("deleteerror"),
                            (Object[]) new String[] { to.toString() }));
                }
            } else {
                throw new IOException(MessageFormat.format(labels.getString("alreadyexistserror"),
                        (Object[]) new String[] { to.toString() }));
            }
        }

        if (from.renameTo(to))
            return;

        InputStream in = null;
        OutputStream out = null;
        try {
            in = new FileInputStream(from);
            out = new FileOutputStream(to);
            copy(in, out);
            in.close();
            in = null;
            out.flush();
            out.close();
            out = null;
            if (!from.delete()) {
                throw new IOException(MessageFormat.format(labels.getString("deleteoriginalerror"),
                        (Object[]) new String[] { from.toString(), to.toString() }));
            }
        } finally {
            if (in != null) {
                in.close();
                in = null;
            }
            if (out != null) {
                out.flush();
                out.close();
                out = null;
            }
        }
    }

    /**
     * Buffer size when reading from input stream.
     *
     * @since ostermillerutils 1.00.00
     */
    private final static int BUFFER_SIZE = 1024;

    /**
     * Copy the data from the input stream to the output stream.
     *
     * @param in data source
     * @param out data destination
     * @throws IOException in an input or output error occurs
     *
     * @since ostermillerutils 1.00.00
     */
    private static void copy(InputStream in, OutputStream out) throws IOException {
        byte[] buffer = new byte[BUFFER_SIZE];
        int read;
        while ((read = in.read(buffer)) != -1) {
            out.write(buffer, 0, read);
        }
    }
}