com.dvlcube.cuber.utils.FileUtils.java Source code

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/*
  This file is part of Cuber.
    
Cuber 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 3 of the License, or
(at your option) any later version.
    
Cuber 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 Cuber.  If not, see <http://www.gnu.org/licenses/>.
 */
package com.dvlcube.cuber.utils;

import java.io.BufferedReader;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.FileReader;
import java.io.IOException;
import java.util.ArrayList;
import java.util.List;

import org.apache.commons.io.IOUtils;

/**
 * 
 * @since 07/07/2013
 * @author wonka
 */
public class FileUtils {
    public static final char EXTENSION_SEPARATOR = '.';
    public static final char UNIX_SEPARATOR = '/';
    public static final char WINDOWS_SEPARATOR = '\\';

    /**
     * @param file
     *            input.
     * @return the first line of a file.
     * @since 07/07/2013
     * @author wonka
     */
    public static String firstLine(File file) {
        return head(file, 1).get(0);
    }

    /**
     * @param file
     *            input.
     * @param nLines
     *            desired number of lines.
     * @return the first n lines of text.
     * @since 07/07/2013
     * @author wonka
     */
    public static List<String> head(File file, int nLines) {
        if (file == null)
            throw new IllegalStateException("file not initialized");

        try (BufferedReader reader = new BufferedReader(new FileReader(file))) {
            int i = 0;
            ArrayList<String> lines = new ArrayList<>();
            String line = null;
            while ((line = reader.readLine()) != null && i < nLines) {
                lines.add(line);
                i++;
            }
            return lines;
        } catch (IOException e) {
            e.printStackTrace();
        }
        return null;
    }

    /**
     * http://grepcode.com/file/repo1.maven.org/maven2/commons-io/commons-io/1.2/org/apache/commons/io/
     * <p>
     * Removes the extension from a filename. This method returns the textual part of the filename before the
     * last dot. There must be no directory separator after the dot.
     * <p>
     * foo.txt --> foo <br>
     * a\b\c.jpg --> a\b\c <br>
     * a\b\c --> a\b\c <br>
     * a.b\c --> a.b\c
     * 
     * The output will be the same irrespective of the machine that the code is running on.
     * 
     * @param filename
     *            the filename to query, null returns null.
     * @return the filename minus the extension
     * @since 09/07/2013
     * @author wonka
     */
    public static String removeExtension(String filename) {
        if (filename == null) {
            return null;
        }
        int index = indexOfExtension(filename);
        if (index == -1) {
            return filename;
        } else {
            return filename.substring(0, index);
        }
    }

    public static int indexOfExtension(String filename) {
        if (filename == null) {
            return -1;
        }
        int extensionPos = filename.lastIndexOf(EXTENSION_SEPARATOR);
        int lastSeparator = indexOfLastSeparator(filename);
        return (lastSeparator > extensionPos ? -1 : extensionPos);
    }

    public static int indexOfLastSeparator(String filename) {
        if (filename == null) {
            return -1;
        }
        int lastUnixPos = filename.lastIndexOf(UNIX_SEPARATOR);
        int lastWindowsPos = filename.lastIndexOf(WINDOWS_SEPARATOR);
        return Math.max(lastUnixPos, lastWindowsPos);
    }

    /**
     * Copies a file to a directory preserving the file date. This method copies the contents of the specified
     * source file to a file of the same name in the specified destination directory. The destination
     * directory is created if it does not exist. If the destination file exists, then this method will
     * overwrite it.
     * 
     * @param srcFile
     *            an existing file to copy, must not be null
     * @param destDir
     *            the directory to place the copy in, must not be null
     * @throws NullPointerException
     *             if source or destination is null
     * @throws IOException
     *             if source or destination is invalid
     * @throws IOException
     *             if an IO error occurs during copying
     * @since 09/07/2013
     * @author wonka
     */
    public static void copyFileToDirectory(File srcFile, File destDir) throws IOException {
        if (destDir == null) {
            throw new NullPointerException("Destination must not be null");
        }
        if (destDir.exists() && destDir.isDirectory() == false) {
            throw new IllegalArgumentException("Destination '" + destDir + "' is not a directory");
        }
        copyFile(srcFile, new File(destDir, srcFile.getName()), true);
    }

    public static void copyFile(File srcFile, File destFile, boolean preserveFileDate) throws IOException {
        if (srcFile == null) {
            throw new NullPointerException("Source must not be null");
        }
        if (destFile == null) {
            throw new NullPointerException("Destination must not be null");
        }
        if (srcFile.exists() == false) {
            throw new FileNotFoundException("Source '" + srcFile + "' does not exist");
        }
        if (srcFile.isDirectory()) {
            throw new IOException("Source '" + srcFile + "' exists but is a directory");
        }
        if (srcFile.getCanonicalPath().equals(destFile.getCanonicalPath())) {
            throw new IOException("Source '" + srcFile + "' and destination '" + destFile + "' are the same");
        }
        if (destFile.getParentFile() != null && destFile.getParentFile().exists() == false) {
            if (destFile.getParentFile().mkdirs() == false) {
                throw new IOException("Destination '" + destFile + "' directory cannot be created");
            }
        }
        if (destFile.exists() && destFile.canWrite() == false) {
            throw new IOException("Destination '" + destFile + "' exists but is read-only");
        }
        doCopyFile(srcFile, destFile, preserveFileDate);
    }

    private static void doCopyFile(File srcFile, File destFile, boolean preserveFileDate) throws IOException {
        if (destFile.exists() && destFile.isDirectory()) {
            throw new IOException("Destination '" + destFile + "' exists but is a directory");
        }

        FileInputStream input = new FileInputStream(srcFile);
        try {
            FileOutputStream output = new FileOutputStream(destFile);
            try {
                IOUtils.copy(input, output);
            } finally {
                IOUtils.closeQuietly(output);
            }
        } finally {
            IOUtils.closeQuietly(input);
        }

        if (srcFile.length() != destFile.length()) {
            throw new IOException("Failed to copy full contents from '" + srcFile + "' to '" + destFile + "'");
        }
        if (preserveFileDate) {
            destFile.setLastModified(srcFile.lastModified());
        }
    }

    /**
     * @param file
     * @param dir
     * @return the new file.
     * @since 09/07/2013
     * @author wonka
     */
    public static File moveFileToDirectory(File file, File dir) {
        try {
            String fileName = file.getName();
            copyFileToDirectory(file, dir);
            file.delete();
            return new File(dir, fileName);
        } catch (IOException e) {
            e.printStackTrace();
            throw new RuntimeException("couldn't move '" + file + "' to '" + dir + "'");
        }
    }
}