package org.apache.maven.shared.utils.io;
   
   /*
    * Licensed to the Apache Software Foundation (ASF) under one
    * or more contributor license agreements.  See the NOTICE file
    * distributed with this work for additional information
    * regarding copyright ownership.  The ASF licenses this file
    * to you 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.
   */
  
  import org.apache.maven.shared.utils.Os;
  import org.apache.maven.shared.utils.StringUtils;
  
  import javax.annotation.Nonnull;
  import javax.annotation.Nullable;
  import javax.annotation.WillClose;
  import java.io.BufferedReader;
  import java.io.File;
  import java.io.FileInputStream;
  import java.io.FileOutputStream;
  import java.io.FileReader;
  import java.io.FileWriter;
  import java.io.IOException;
  import java.io.InputStream;
  import java.io.InputStreamReader;
  import java.io.OutputStream;
  import java.io.OutputStreamWriter;
  import java.io.Reader;
  import java.io.Writer;
  import java.net.URL;
  import java.nio.channels.FileChannel;
  import java.security.SecureRandom;
  import java.text.DecimalFormat;
  import java.util.ArrayList;
  import java.util.Arrays;
  import java.util.Collections;
  import java.util.List;
  import java.util.Random;
  
  /**
   * This class provides basic facilities for manipulating files and file paths.
   * <p/>
   * <h3>Path-related methods</h3>
   * <p/>
   * <p>Methods exist to retrieve the components of a typical file path. For example
   * <code>/www/hosted/mysite/index.html</code>, can be broken into:
   * <ul>
   * <li><code>/www/hosted/mysite/index</code> -- retrievable through {@link #removeExtension}</li>
   * <li><code>html</code> -- retrievable through {@link #getExtension}</li>
   * </ul>
   * </p>
   * <p/>
   * <h3>File-related methods</h3>
   * <p/>
   * There are methods to  create a {@link #toFile File from a URL}, copy a
   * copy a {@link #copyFile File to another File},
   * copy a {@link #copyURLToFile URL's contents to a File},
   * as well as methods to {@link #deleteDirectory(File) delete} and {@link #cleanDirectory(File)
   * clean} a directory.
   * </p>
   * <p/>
   * Common {@link java.io.File} manipulation routines.
   * <p/>
   * Taken from the commons-utils repo.
   * Also code from Alexandria's FileUtils.
   * And from Avalon Excalibur's IO.
   * And from Ant.
   *
   * @author <a href="mailto:burton@relativity.yi.org">Kevin A. Burton</A>
   * @author <a href="mailto:sanders@apache.org">Scott Sanders</a>
   * @author <a href="mailto:dlr@finemaltcoding.com">Daniel Rall</a>
   * @author <a href="mailto:Christoph.Reck@dlr.de">Christoph.Reck</a>
   * @author <a href="mailto:peter@apache.org">Peter Donald</a>
   * @author <a href="mailto:jefft@apache.org">Jeff Turner</a>
   * @version $Id: FileUtils.java 1706704 2015-10-04 17:35:19Z khmarbaise $
   */
  public class FileUtils
  {
      /**
       * protected constructor.
       */
      protected FileUtils()
      {
          // This is a utility class.  Normally dont instantiate
      }
  
      /**
       * The number of bytes in a kilobyte.
      */
     private static final int ONE_KB = 1024;
 
     /**
      * The number of bytes in a megabyte.
      */
     private static final int ONE_MB = ONE_KB * ONE_KB;
 
     /**
      * The number of bytes in a gigabyte.
      */
     private static final int ONE_GB = ONE_KB * ONE_MB;
 
     /**
      * The file copy buffer size (30 MB)
      */
     private static final long FILE_COPY_BUFFER_SIZE = ONE_MB * 30;
 
     /**
      * The vm line separator
      */
     private static final String FS = System.getProperty( "file.separator" );
 
     /**
      * Non-valid Characters for naming files, folders under Windows: <code>":", "*", "?", "\"", "<", ">", "|"</code>
      *
      * @see <a href="http://support.microsoft.com/?scid=kb%3Ben-us%3B177506&x=12&y=13">
      * http://support.microsoft.com/?scid=kb%3Ben-us%3B177506&x=12&y=13</a>;
      */
     private static final String[] INVALID_CHARACTERS_FOR_WINDOWS_FILE_NAME = { ":", "*", "?", "\"", "<", ">", "|" };
 
     /**
      * @return the default excludes pattern
      * @see DirectoryScanner#DEFAULTEXCLUDES
      */
     @Nonnull public static String[] getDefaultExcludes()
     {
         return DirectoryScanner.DEFAULTEXCLUDES;
     }
 
     /**
      * @return the default excludes pattern as list.
      * @see #getDefaultExcludes()
      */
     @Nonnull public static List<String> getDefaultExcludesAsList()
     {
         return Arrays.asList( getDefaultExcludes() );
     }
 
     /**
      * @return the default excludes pattern as comma separated string.
      * @see DirectoryScanner#DEFAULTEXCLUDES
      * @see StringUtils#join(Object[], String)
      */
     @Nonnull public static String getDefaultExcludesAsString()
     {
         return StringUtils.join( DirectoryScanner.DEFAULTEXCLUDES, "," );
     }
 
     /**
      * Returns the directory path portion of a file specification string.
      * Matches the equally named unix command.
      *
      * @param filename the file path
      * @return The directory portion excluding the ending file separator.
      */
     @Nonnull public static String dirname( @Nonnull String filename )
     {
         int i = filename.lastIndexOf( File.separator );
         return ( i >= 0 ? filename.substring( 0, i ) : "" );
     }
 
     /**
      * Returns the filename portion of a file specification string.
      *
      * @param filename the file path
      * @return The filename string with extension.
      */
     @Nonnull public static String filename( @Nonnull String filename )
     {
         int i = filename.lastIndexOf( File.separator );
         return ( i >= 0 ? filename.substring( i + 1 ) : filename );
     }
 
     /**
      * Returns the extension portion of a file specification string.
      * This everything after the last dot '.' in the filename (NOT including
      * the dot).
      *
      * @param filename the file path
      * @return the extension of the file
      */
     @Nonnull public static String extension( @Nonnull String filename )
     {
         // Ensure the last dot is after the last file separator
         int lastSep = filename.lastIndexOf( File.separatorChar );
         int lastDot;
         if ( lastSep < 0 )
         {
             lastDot = filename.lastIndexOf( '.' );
         }
         else
         {
             lastDot = filename.substring( lastSep + 1 ).lastIndexOf( '.' );
             if ( lastDot >= 0 )
             {
                 lastDot += lastSep + 1;
             }
         }
 
         if ( lastDot >= 0 && lastDot > lastSep )
         {
             return filename.substring( lastDot + 1 );
         }
 
         return "";
     }
 
     /**
      * Check if a file exits.
      *
      * @param fileName the file path.
      * @return true if file exists.
      */
     public static boolean fileExists( @Nonnull String fileName )
     {
         File file = new File( fileName );
         return file.exists();
     }
 
     /**
      * Note: the file content is read with platform encoding.
      *
      * @param file the file path
      * @return the file content using the platform encoding.
      * @throws IOException if any
      */
     @Nonnull public static String fileRead( @Nonnull String file )
         throws IOException
     {
         return fileRead( file, null );
     }
 
     /**
      * @param file     the file path
      * @param encoding the wanted encoding
      * @return the file content using the specified encoding.
      * @throws IOException if any
      */
     @Nonnull private static String fileRead( @Nonnull String file, @Nullable String encoding )
         throws IOException
     {
         return fileRead( new File( file ), encoding );
     }
 
     /**
      * Note: the file content is read with platform encoding
      *
      * @param file the file path
      * @return the file content using the platform encoding.
      * @throws IOException if any
      */
     @Nonnull public static String fileRead( @Nonnull File file )
         throws IOException
     {
         return fileRead( file, null );
     }
 
     /**
      * @param file     the file path
      * @param encoding the wanted encoding
      * @return the file content using the specified encoding.
      * @throws IOException if any
      */
     @Nonnull public static String fileRead( @Nonnull File file, @Nullable String encoding )
         throws IOException
     {
         StringBuilder buf = new StringBuilder();
 
         Reader reader = null;
 
         try
         {
             if ( encoding != null )
             {
                 reader = new InputStreamReader( new FileInputStream( file ), encoding );
             }
             else
             {
                 reader = new InputStreamReader( new FileInputStream( file ) );
             }
             int count;
             char[] b = new char[512];
             while ( ( count = reader.read( b ) ) > 0 )  // blocking read
             {
                 buf.append( b, 0, count );
             }
         }
         finally
         {
             IOUtil.close( reader );
         }
 
         return buf.toString();
     }
 
     /**
      * @param file the file path
      * @return the file content lines as String[] using the systems default encoding.
      * An empty List if the file didn't exist.
      * @throws IOException in case of failure.
      */
     @Nonnull public static String[] fileReadArray( @Nonnull File file )
         throws IOException
     {
         List<String> files = loadFile( file );
 
         return files.toArray( new String[files.size()] );
     }
 
     /**
      * Appends data to a file. The file will be created if it does not exist.
      * Note: the data is written with platform encoding
      *
      * @param fileName The path of the file to write.
      * @param data     The content to write to the file.
      * @throws IOException if any
      */
     public static void fileAppend( @Nonnull String fileName, @Nonnull String data )
         throws IOException
     {
         fileAppend( fileName, null, data );
     }
 
     /**
      * Appends data to a file. The file will be created if it does not exist.
      *
      * @param fileName The path of the file to write.
      * @param encoding The encoding of the file.
      * @param data     The content to write to the file.
      * @throws IOException if any
      */
     public static void fileAppend( @Nonnull String fileName, @Nullable String encoding, @Nonnull String data )
         throws IOException
     {
         FileOutputStream out = null;
         try
         {
             out = new FileOutputStream( fileName, true );
             if ( encoding != null )
             {
                 out.write( data.getBytes( encoding ) );
             }
             else
             {
                 out.write( data.getBytes() );
             }
         }
         finally
         {
             IOUtil.close( out );
         }
     }
 
     /**
      * Writes data to a file. The file will be created if it does not exist.
      * Note: the data is written with platform encoding
      *
      * @param fileName The path of the file to write.
      * @param data     The content to write to the file.
      * @throws IOException if any
      */
     public static void fileWrite( @Nonnull String fileName, @Nonnull String data )
         throws IOException
     {
         fileWrite( fileName, null, data );
     }
 
     /**
      * Writes data to a file. The file will be created if it does not exist.
      *
      * @param fileName The path of the file to write.
      * @param encoding The encoding of the file.
      * @param data     The content to write to the file.
      * @throws IOException if any
      */
     public static void fileWrite( @Nonnull String fileName, @Nullable String encoding, @Nonnull String data )
         throws IOException
     {
         File file = new File( fileName );
         fileWrite( file, encoding, data );
     }
 
     /**
      * Writes data to a file. The file will be created if it does not exist.
      *
      * @param file     The path of the file to write.
      * @param encoding The encoding of the file.
      * @param data     The content to write to the file.
      * @throws IOException if any
      */
     public static void fileWrite( @Nonnull File file, @Nullable String encoding, @Nonnull String data )
         throws IOException
     {
         Writer writer = null;
         try
         {
             OutputStream out = new FileOutputStream( file );
             if ( encoding != null )
             {
                 writer = new OutputStreamWriter( out, encoding );
             }
             else
             {
                 writer = new OutputStreamWriter( out );
             }
             writer.write( data );
         }
         finally
         {
             IOUtil.close( writer );
         }
     }
 
     /**
      * Writes String array data to a file in the systems default encoding.
      * The file will be created if it does not exist.
      *
      * @param file The path of the file to write.
      * @param data The content to write to the file.
      * @throws IOException if any
      */
     public static void fileWriteArray( @Nonnull File file, @Nullable String... data )
         throws IOException
     {
         fileWriteArray( file, null, data );
     }
 
     /**
      * Writes String array data to a file. The file will be created if it does not exist.
      *
      * @param file     The path of the file to write.
      * @param encoding The encoding of the file.
      * @param data     The content to write to the file.
      * @throws IOException if any
      */
     public static void fileWriteArray( @Nonnull File file, @Nullable String encoding, @Nullable String... data )
         throws IOException
     {
         Writer writer = null;
         try
         {
             OutputStream out = new FileOutputStream( file );
             if ( encoding != null )
             {
                 writer = new OutputStreamWriter( out, encoding );
             }
             else
             {
                 writer = new OutputStreamWriter( out );
             }
 
             for ( int i = 0; data != null && i < data.length; i++ )
             {
                 writer.write( data[i] );
                 if ( i < data.length )
                 {
                     writer.write( "\n" );
                 }
             }
         }
         finally
         {
             IOUtil.close( writer );
         }
     }
 
     /**
      * Deletes a file.
      *
      * @param fileName The path of the file to delete.
      */
     public static void fileDelete( @Nonnull String fileName )
     {
         File file = new File( fileName );
         //noinspection ResultOfMethodCallIgnored
         deleteLegacyStyle( file );
     }
 
     /**
      * Given a directory and an array of extensions return an array of compliant files.
      * <p/>
      * TODO Should an ignore list be passed in?
      * TODO Should a recurse flag be passed in?
      * <p/>
      * The given extensions should be like "java" and not like ".java"
      *
      * @param directory  The path of the directory.
      * @param extensions an array of expected extensions.
      * @return An array of files for the wanted extensions.
      */
     public static String[] getFilesFromExtension( @Nonnull String directory, @Nonnull String... extensions )
     {
         List<String> files = new ArrayList<String>();
 
         File currentDir = new File( directory );
 
         String[] unknownFiles = currentDir.list();
 
         if ( unknownFiles == null )
         {
             return new String[0];
         }
 
         for ( String unknownFile : unknownFiles )
         {
             String currentFileName = directory + System.getProperty( "file.separator" ) + unknownFile;
             File currentFile = new File( currentFileName );
 
             if ( currentFile.isDirectory() )
             {
                 // ignore all CVS directories...
                 if ( currentFile.getName().equals( "CVS" ) )
                 {
                     continue;
                 }
 
                 // ok... transverse into this directory and get all the files... then combine
                 // them with the current list.
 
                 String[] fetchFiles = getFilesFromExtension( currentFileName, extensions );
                 files = blendFilesToList( files, fetchFiles );
             }
             else
             {
                 // ok... add the file
 
                 String add = currentFile.getAbsolutePath();
                 if ( isValidFile( add, extensions ) )
                 {
                     files.add( add );
                 }
             }
         }
 
         // ok... move the Vector into the files list...
         String[] foundFiles = new String[files.size()];
         files.toArray( foundFiles );
 
         return foundFiles;
     }
 
     /**
      * Private helper method for getFilesFromExtension()
      */
     @Nonnull private static List<String> blendFilesToList( @Nonnull List<String> v, @Nonnull String... files )
     {
         Collections.addAll( v, files );
 
         return v;
     }
 
     /**
      * Checks to see if a file is of a particular type(s).
      * Note that if the file does not have an extension, an empty string
      * (&quot;&quot;) is matched for.
      */
     private static boolean isValidFile( @Nonnull String file, @Nonnull String... extensions )
     {
         String extension = extension( file );
 
         // ok.. now that we have the "extension" go through the current know
         // excepted extensions and determine if this one is OK.
 
         for ( String extension1 : extensions )
         {
             if ( extension1.equals( extension ) )
             {
                 return true;
             }
         }
 
         return false;
 
     }
 
     /**
      * Simple way to make a directory
      *
      * @param dir the directory to create
      * @throws IllegalArgumentException if the dir contains illegal Windows characters under Windows OS.
      * @see #INVALID_CHARACTERS_FOR_WINDOWS_FILE_NAME
      */
     public static void mkdir( @Nonnull String dir )
     {
         File file = new File( dir );
 
         if ( Os.isFamily( Os.FAMILY_WINDOWS ) && !isValidWindowsFileName( file ) )
         {
             throw new IllegalArgumentException(
                 "The file (" + dir + ") cannot contain any of the following characters: \n" + StringUtils.join(
                     INVALID_CHARACTERS_FOR_WINDOWS_FILE_NAME, " " ) );
         }
 
         if ( !file.exists() )
         {
             //noinspection ResultOfMethodCallIgnored
             file.mkdirs();
         }
     }
 
     /**
      * Compare the contents of two files to determine if they are equal or not.
      *
      * @param file1 the first file
      * @param file2 the second file
      * @return true if the content of the files are equal or they both don't exist, false otherwise
      * @throws IOException if any
      */
     public static boolean contentEquals( @Nonnull final File file1, @Nonnull final File file2 )
         throws IOException
     {
         final boolean file1Exists = file1.exists();
         if ( file1Exists != file2.exists() )
         {
             return false;
         }
 
         if ( !file1Exists )
         {
             // two not existing files are equal
             return true;
         }
 
         if ( file1.isDirectory() || file2.isDirectory() )
         {
             // don't want to compare directory contents
             return false;
         }
 
         InputStream input1 = null;
         InputStream input2 = null;
         try
         {
             input1 = new FileInputStream( file1 );
             input2 = new FileInputStream( file2 );
             return IOUtil.contentEquals( input1, input2 );
 
         }
         finally
         {
             IOUtil.close( input1 );
             IOUtil.close( input2 );
         }
     }
 
     /**
      * Convert from a <code>URL</code> to a <code>File</code>.
      *
      * @param url File URL.
      * @return The equivalent <code>File</code> object, or <code>null</code> if the URL's protocol
      * is not <code>file</code>
      */
     @Nullable public static File toFile( @Nullable final URL url )
     {
         if ( url == null || !url.getProtocol().equalsIgnoreCase( "file" ) )
         {
             return null;
         }
 
         String filename = url.getFile().replace( '/', File.separatorChar );
         int pos = -1;
         while ( ( pos = filename.indexOf( '%', pos + 1 ) ) >= 0 )
         {
             if ( pos + 2 < filename.length() )
             {
                 String hexStr = filename.substring( pos + 1, pos + 3 );
                 char ch = (char) Integer.parseInt( hexStr, 16 );
                 filename = filename.substring( 0, pos ) + ch + filename.substring( pos + 3 );
             }
         }
         return new File( filename );
     }
 
     /**
      * Convert the array of Files into a list of URLs.
      *
      * @param files the array of files
      * @return the array of URLs
      * @throws IOException if an error occurs
      */
     @Nonnull public static URL[] toURLs( @Nonnull final File... files )
         throws IOException
     {
         final URL[] urls = new URL[files.length];
 
         for ( int i = 0; i < urls.length; i++ )
         {
             urls[i] = files[i].toURI().toURL();
         }
 
         return urls;
     }
 
     /**
      * Remove extension from filename.
      * ie
      * <pre>
      * foo.txt    --> foo
      * a\b\c.jpg --> a\b\c
      * a\b\c     --> a\b\c
      * </pre>
      *
      * @param filename the path of the file
      * @return the filename minus extension
      */
     @Nonnull public static String removeExtension( @Nonnull final String filename )
     {
         String ext = extension( filename );
 
         if ( "".equals( ext ) )
         {
             return filename;
         }
 
         final int index = filename.lastIndexOf( ext ) - 1;
         return filename.substring( 0, index );
     }
 
     /**
      * Get extension from filename.
      * ie
      * <pre>
      * foo.txt    --> "txt"
      * a\b\c.jpg --> "jpg"
      * a\b\c     --> ""
      * </pre>
      *
      * @param filename the path of the file
      * @return the extension of filename or "" if none
      */
     @Nonnull public static String getExtension( @Nonnull final String filename )
     {
         return extension( filename );
     }
 
     /**
      * Copy file from source to destination. If <code>destinationDirectory</code> does not exist, it
      * (and any parent directories) will be created. If a file <code>source</code> in
      * <code>destinationDirectory</code> exists, it will be overwritten.
      *
      * @param source               An existing <code>File</code> to copy.
      * @param destinationDirectory A directory to copy <code>source</code> into.
      * @throws java.io.FileNotFoundException if <code>source</code> isn't a normal file.
      * @throws IllegalArgumentException      if <code>destinationDirectory</code> isn't a directory.
      * @throws IOException                   if <code>source</code> does not exist, the file in
      *                                       <code>destinationDirectory</code> cannot be written to, or an IO error
      *                                       occurs during copying.
      */
     public static void copyFileToDirectory( @Nonnull final File source, @Nonnull final File destinationDirectory )
         throws IOException
     {
         if ( destinationDirectory.exists() && !destinationDirectory.isDirectory() )
         {
             throw new IllegalArgumentException( "Destination is not a directory" );
         }
 
         copyFile( source, new File( destinationDirectory, source.getName() ) );
     }
 
     /**
      * Copy file from source to destination only if source is newer than the target file.
      * If <code>destinationDirectory</code> does not exist, it
      * (and any parent directories) will be created. If a file <code>source</code> in
      * <code>destinationDirectory</code> exists, it will be overwritten.
      *
      * @param source               An existing <code>File</code> to copy.
      * @param destinationDirectory A directory to copy <code>source</code> into.
      * @throws java.io.FileNotFoundException if <code>source</code> isn't a normal file.
      * @throws IllegalArgumentException      if <code>destinationDirectory</code> isn't a directory.
      * @throws IOException                   if <code>source</code> does not exist, the file in
      *                                       <code>destinationDirectory</code> cannot be written to, or an IO error
      *                                       occurs during copying.
      */
     private static void copyFileToDirectoryIfModified( @Nonnull final File source,
                                                        @Nonnull final File destinationDirectory )
         throws IOException
     {
         if ( destinationDirectory.exists() && !destinationDirectory.isDirectory() )
         {
             throw new IllegalArgumentException( "Destination is not a directory" );
         }
 
         copyFileIfModified( source, new File( destinationDirectory, source.getName() ) );
     }
 
 
     /**
      * Copy file from source to destination. The directories up to <code>destination</code> will be
      * created if they don't already exist. <code>destination</code> will be overwritten if it
      * already exists.
      *
      * @param source      An existing non-directory <code>File</code> to copy bytes from.
      * @param destination A non-directory <code>File</code> to write bytes to (possibly
      *                    overwriting).
      * @throws IOException                   if <code>source</code> does not exist, <code>destination</code> cannot be
      *                                       written to, or an IO error occurs during copying.
      * @throws java.io.FileNotFoundException if <code>destination</code> is a directory
      */
     public static void copyFile( @Nonnull final File source, @Nonnull final File destination )
         throws IOException
     {
         //check source exists
         if ( !source.exists() )
         {
             final String message = "File " + source + " does not exist";
             throw new IOException( message );
         }
         if ( Java7Support.isAtLeastJava7() && Java7Support.isSymLink( source ) )
         {
             File target = Java7Support.readSymbolicLink( source );
             Java7Support.createSymbolicLink( destination, target );
             return;
         }
 
         //check source != destination, see PLXUTILS-10
         if ( source.getCanonicalPath().equals( destination.getCanonicalPath() ) )
         {
             //if they are equal, we can exit the method without doing any work
             return;
         }
 
         mkdirsFor( destination );
 
         doCopyFile( source, destination );
 
         if ( source.length() != destination.length() )
         {
             final String message = "Failed to copy full contents from " + source + " to " + destination;
             throw new IOException( message );
         }
     }
 
     private static void mkdirsFor( @Nonnull File destination )
     {
         //does destination directory exist ?
         if ( destination.getParentFile() != null && !destination.getParentFile().exists() )
         {
             //noinspection ResultOfMethodCallIgnored
             destination.getParentFile().mkdirs();
         }
     }
 
     private static void doCopyFile( @Nonnull File source, @Nonnull File destination )
         throws IOException
     {
         FileInputStream fis = null;
         FileOutputStream fos = null;
         FileChannel input = null;
         FileChannel output = null;
         try
         {
             fis = new FileInputStream( source );
             fos = new FileOutputStream( destination );
             input = fis.getChannel();
             output = fos.getChannel();
             long size = input.size();
             long pos = 0;
             long count;
             while ( pos < size )
             {
                 count = size - pos > FILE_COPY_BUFFER_SIZE ? FILE_COPY_BUFFER_SIZE : size - pos;
                 pos += output.transferFrom( input, pos, count );
             }
         }
         finally
         {
             IOUtil.close( output );
             IOUtil.close( fos );
             IOUtil.close( input );
             IOUtil.close( fis );
         }
     }
 
     /**
      * Copy file from source to destination only if source timestamp is later than the destination timestamp.
      * The directories up to <code>destination</code> will be created if they don't already exist.
      * <code>destination</code> will be overwritten if it already exists.
      *
      * @param source      An existing non-directory <code>File</code> to copy bytes from.
      * @param destination A non-directory <code>File</code> to write bytes to (possibly
      *                    overwriting).
      * @return true if no problem occured
      * @throws IOException if <code>source</code> does not exist, <code>destination</code> cannot be
      *                     written to, or an IO error occurs during copying.
      */
     private static boolean copyFileIfModified( @Nonnull final File source, @Nonnull final File destination )
         throws IOException
     {
         if ( destination.lastModified() < source.lastModified() )
         {
             copyFile( source, destination );
 
             return true;
         }
 
         return false;
     }
 
     /**
      * Copies bytes from the URL <code>source</code> to a file <code>destination</code>.
      * The directories up to <code>destination</code> will be created if they don't already exist.
      * <code>destination</code> will be overwritten if it already exists.
      *
      * @param source      A <code>URL</code> to copy bytes from.
      * @param destination A non-directory <code>File</code> to write bytes to (possibly
      *                    overwriting).
      * @throws IOException if
      *                     <ul>
      *                     <li><code>source</code> URL cannot be opened</li>
      *                     <li><code>destination</code> cannot be written to</li>
      *                     <li>an IO error occurs during copying</li>
      *                     </ul>
      */
     public static void copyURLToFile( @Nonnull final URL source, @Nonnull final File destination )
         throws IOException
     {
         copyStreamToFile( source.openStream(), destination );
     }
 
     /**
      * Copies bytes from the {@link InputStream} <code>source</code> to a file <code>destination</code>.
      * The directories up to <code>destination</code> will be created if they don't already exist.
      * <code>destination</code> will be overwritten if it already exists.
      *
      * @param source      An {@link InputStream} to copy bytes from. This stream is
      *                    guaranteed to be closed.
      * @param destination A non-directory <code>File</code> to write bytes to (possibly
      *                    overwriting).
      * @throws IOException if
      *                     <ul>
      *                     <li><code>source</code> URL cannot be opened</li>
      *                     <li><code>destination</code> cannot be written to</li>
      *                     <li>an IO error occurs during copying</li>
      *                     </ul>
      */
     private static void copyStreamToFile( @Nonnull @WillClose final InputStream source,
                                           @Nonnull final File destination )
         throws IOException
     {
         FileOutputStream output = null;
         try
         {
             //does destination directory exist ?
             if ( destination.getParentFile() != null && !destination.getParentFile().exists() )
             {
                 //noinspection ResultOfMethodCallIgnored
                 destination.getParentFile().mkdirs();
             }
 
             //make sure we can write to destination
             if ( destination.exists() && !destination.canWrite() )
             {
                 final String message = "Unable to open file " + destination + " for writing.";
                 throw new IOException( message );
             }
 
             output = new FileOutputStream( destination );
             IOUtil.copy( source, output );
         }
         finally
         {
             IOUtil.close( source );
             IOUtil.close( output );
         }
     }
 
     /**
      * Normalize a path.
      * Eliminates "/../" and "/./" in a string. Returns <code>null</code> if the ..'s went past the
      * root.
      * Eg:
      * <pre>
      * /foo//               -->     /foo/
      * /foo/./              -->     /foo/
      * /foo/../bar          -->     /bar
      * /foo/../bar/         -->     /bar/
      * /foo/../bar/../baz   -->     /baz
      * //foo//./bar         -->     /foo/bar
      * /../                 -->     null
      * </pre>
      *
      * @param path the path to normalize
      * @return the normalized String, or <code>null</code> if too many ..'s.
      */
     @Nonnull public static String normalize( @Nonnull final String path )
     {
         String normalized = path;
         // Resolve occurrences of "//" in the normalized path
         while ( true )
         {
             int index = normalized.indexOf( "//" );
             if ( index < 0 )
             {
                 break;
             }
             normalized = normalized.substring( 0, index ) + normalized.substring( index + 1 );
         }
 
         // Resolve occurrences of "/./" in the normalized path
         while ( true )
         {
             int index = normalized.indexOf( "/./" );
             if ( index < 0 )
             {
                 break;
             }
             normalized = normalized.substring( 0, index ) + normalized.substring( index + 2 );
         }
 
         // Resolve occurrences of "/../" in the normalized path
         while ( true )
         {
             int index = normalized.indexOf( "/../" );
             if ( index < 0 )
             {
                 break;
             }
             if ( index == 0 )
             {
                 return null;  // Trying to go outside our context
             }
             int index2 = normalized.lastIndexOf( '/', index - 1 );
             normalized = normalized.substring( 0, index2 ) + normalized.substring( index + 3 );
         }
 
         // Return the normalized path that we have completed
         return normalized;
     }
 
     /**
      * Resolve a file <code>filename</code> to it's canonical form. If <code>filename</code> is
      * relative (doesn't start with <code>/</code>), it will be resolved relative to
      * <code>baseFile</code>, otherwise it is treated as a normal root-relative path.
      *
      * @param baseFile Where to resolve <code>filename</code> from, if <code>filename</code> is
      *                 relative.
      * @param filename Absolute or relative file path to resolve.
      * @return The canonical <code>File</code> of <code>filename</code>.
      */
     @Nonnull public static File resolveFile( final File baseFile, @Nonnull String filename )
     {
         String filenm = filename;
         if ( '/' != File.separatorChar )
         {
             filenm = filename.replace( '/', File.separatorChar );
         }
 
         if ( '\\' != File.separatorChar )
         {
             filenm = filename.replace( '\\', File.separatorChar );
         }
 
         // deal with absolute files
         if ( filenm.startsWith( File.separator ) || ( Os.isFamily( Os.FAMILY_WINDOWS ) && filenm.indexOf( ":" ) > 0 ) )
         {
             File file = new File( filenm );
 
             try
             {
                 file = file.getCanonicalFile();
             }
             catch ( final IOException ioe )
             {
                 // nop
             }
 
             return file;
         }
         // FIXME: I'm almost certain this // removal is unnecessary, as getAbsoluteFile() strips
         // them. However, I'm not sure about this UNC stuff. (JT)
         final char[] chars = filename.toCharArray();
         final StringBuilder sb = new StringBuilder();
 
         //remove duplicate file separators in succession - except
         //on win32 at start of filename as UNC filenames can
         //be \\AComputer\AShare\myfile.txt
         int start = 0;
         if ( '\\' == File.separatorChar )
         {
             sb.append( filenm.charAt( 0 ) );
             start++;
         }
 
         for ( int i = start; i < chars.length; i++ )
         {
             final boolean doubleSeparator = File.separatorChar == chars[i] && File.separatorChar == chars[i - 1];
 
             if ( !doubleSeparator )
             {
                 sb.append( chars[i] );
             }
         }
 
         filenm = sb.toString();
 
         //must be relative
         File file = ( new File( baseFile, filenm ) ).getAbsoluteFile();
 
         try
         {
             file = file.getCanonicalFile();
         }
         catch ( final IOException ioe )
         {
             // nop
         }
 
         return file;
     }
 
     /**
      * Delete a file. If file is directory delete it and all sub-directories.
      *
      * @param file the file path
      * @throws IOException if any
      */
     public static void forceDelete( @Nonnull final String file )
         throws IOException
     {
         forceDelete( new File( file ) );
     }
 
     /**
      * Delete a file. If file is directory delete it and all sub-directories.
      *
      * @param file a file
      * @throws IOException if any
      */
     public static void forceDelete( @Nonnull final File file )
         throws IOException
     {
         if ( file.isDirectory() )
         {
             deleteDirectory( file );
         }
         else
         {
             /*
              * NOTE: Always try to delete the file even if it appears to be non-existent. This will ensure that a
              * symlink whose target does not exist is deleted, too.
              */
             boolean filePresent = file.getCanonicalFile().exists();
             if ( !deleteFile( file ) && filePresent )
             {
                 final String message = "File " + file + " unable to be deleted.";
                 throw new IOException( message );
             }
         }
     }
 
     /**
      * deletes a file.
      *
      * @param file The file to delete
      * @throws IOException If the file cannot be delted.
      */
 
 
     public static void delete( @Nonnull File file )
         throws IOException
     {
         if ( Java7Support.isAtLeastJava7() )
         {
             Java7Support.delete( file );
         }
         else
         {
             if ( !file.delete() )
             {
                 throw new IOException( "Could not delete " + file.getName() );
             }
         }
     }
 
     /**
      * @param file The file.
      * @return true / false
      */
     public static boolean deleteLegacyStyle( @Nonnull File file )
     {
         if ( Java7Support.isAtLeastJava7() )
         {
             try
             {
                 Java7Support.delete( file );
                 return true;
             }
             catch ( IOException e )
             {
                 return false;
             }
         }
         else
         {
             return file.delete();
         }
     }
 
     /**
      * Accommodate Windows bug encountered in both Sun and IBM JDKs.
      * Others possible. If the delete does not work, call System.gc(),
      * wait a little and try again.
      *
      * @param file a file
      * @throws IOException if any
      */
     private static boolean deleteFile( @Nonnull File file )
         throws IOException
     {
         if ( file.isDirectory() )
         {
             throw new IOException( "File " + file + " isn't a file." );
         }
 
         if ( !deleteLegacyStyle( file ) )
         {
             if ( Os.isFamily( Os.FAMILY_WINDOWS ) )
             {
                 file = file.getCanonicalFile();
                 System.gc();
             }
 
             try
             {
                 Thread.sleep( 10 );
                 return deleteLegacyStyle( file );
             }
             catch ( InterruptedException ex )
             {
                 return deleteLegacyStyle( file );
             }
         }
 
         return true;
     }
 
 
     /**
      * Make a directory.
      *
      * @param file not null
      * @throws IOException              If there already exists a file with specified name or
      *                                  the directory is unable to be created
      * @throws IllegalArgumentException if the file contains illegal Windows characters under Windows OS.
      * @see #INVALID_CHARACTERS_FOR_WINDOWS_FILE_NAME
      */
     public static void forceMkdir( @Nonnull final File file )
         throws IOException
     {
         if ( Os.isFamily( Os.FAMILY_WINDOWS ) && !isValidWindowsFileName( file ) )
         {
             throw new IllegalArgumentException(
                 "The file (" + file.getAbsolutePath() + ") cannot contain any of the following characters: \n"
                     + StringUtils.join( INVALID_CHARACTERS_FOR_WINDOWS_FILE_NAME, " " ) );
         }
 
         if ( file.exists() )
         {
             if ( file.isFile() )
             {
                 final String message =
                     "File " + file + " exists and is " + "not a directory. Unable to create directory.";
                 throw new IOException( message );
             }
         }
         else
         {
             if ( !file.mkdirs() )
             {
                 final String message = "Unable to create directory " + file;
                 throw new IOException( message );
             }
         }
     }
 
     /**
      * Recursively delete a directory.
      *
      * @param directory a directory
      * @throws IOException if any
      */
     public static void deleteDirectory( @Nonnull final String directory )
         throws IOException
     {
         deleteDirectory( new File( directory ) );
     }
 
     /**
      * Recursively delete a directory.
      *
      * @param directory a directory
      * @throws IOException if any
      */
     public static void deleteDirectory( @Nonnull final File directory )
         throws IOException
     {
         if ( !directory.exists() )
         {
             return;
         }
 
         /* try delete the directory before its contents, which will take
          * care of any directories that are really symbolic links.
          */
         if ( deleteLegacyStyle( directory ) )
         {
             return;
         }
 
         cleanDirectory( directory );
         if ( !deleteLegacyStyle( directory ) )
         {
             final String message = "Directory " + directory + " unable to be deleted.";
             throw new IOException( message );
         }
     }
 
     /**
      * Clean a directory without deleting it.
      *
      * @param directory a directory
      * @throws IOException if any
      */
     public static void cleanDirectory( @Nonnull final File directory )
         throws IOException
     {
         if ( !directory.exists() )
         {
             final String message = directory + " does not exist";
             throw new IllegalArgumentException( message );
         }
 
         if ( !directory.isDirectory() )
         {
             final String message = directory + " is not a directory";
             throw new IllegalArgumentException( message );
         }
 
         IOException exception = null;
 
         final File[] files = directory.listFiles();
 
         if ( files == null )
         {
             return;
         }
 
         for ( final File file : files )
         {
             try
             {
                 forceDelete( file );
             }
             catch ( final IOException ioe )
             {
                 exception = ioe;
             }
         }
 
         if ( null != exception )
         {
             throw exception;
         }
     }
 
     /**
      * Recursively count size of a directory.
      *
      * @param directory a directory
      * @return size of directory in bytes.
      */
     public static long sizeOfDirectory( @Nonnull final String directory )
     {
         return sizeOfDirectory( new File( directory ) );
     }
 
     /**
      * Recursively count size of a directory.
      *
      * @param directory a directory
      * @return size of directory in bytes.
      */
     public static long sizeOfDirectory( @Nonnull final File directory )
     {
         if ( !directory.exists() )
         {
             final String message = directory + " does not exist";
             throw new IllegalArgumentException( message );
         }
 
         if ( !directory.isDirectory() )
         {
             final String message = directory + " is not a directory";
             throw new IllegalArgumentException( message );
         }
 
         long size = 0;
 
         final File[] files = directory.listFiles();
         if ( files == null )
         {
             throw new IllegalArgumentException( "Problems reading directory" );
         }
 
         for ( final File file : files )
         {
             if ( file.isDirectory() )
             {
                 size += sizeOfDirectory( file );
             }
             else
             {
                 size += file.length();
             }
         }
 
         return size;
     }
 
     /**
      * Return the files contained in the directory, using inclusion and exclusion Ant patterns,
      * including the directory name in each of the files
      *
      * @param directory the directory to scan
      * @param includes  the includes pattern, comma separated
      * @param excludes  the excludes pattern, comma separated
      * @return a list of File objects
      * @throws IOException in case of failure.
      * @see #getFileNames(File, String, String, boolean)
      */
     @Nonnull
     public static List<File> getFiles( @Nonnull File directory, @Nullable String includes, @Nullable String excludes )
         throws IOException
     {
         return getFiles( directory, includes, excludes, true );
     }
 
     /**
      * Return the files contained in the directory, using inclusion and exclusion Ant patterns
      *
      * @param directory      the directory to scan
      * @param includes       the includes pattern, comma separated
      * @param excludes       the excludes pattern, comma separated
      * @param includeBasedir true to include the base dir in each file
      * @return a list of File objects
      * @throws IOException in case of failure.
      * @see #getFileNames(File, String, String, boolean)
      */
     @Nonnull
     public static List<File> getFiles( @Nonnull File directory, @Nullable String includes, @Nullable String excludes,
                                        boolean includeBasedir )
         throws IOException
     {
         List<String> fileNames = getFileNames( directory, includes, excludes, includeBasedir );
 
         List<File> files = new ArrayList<File>();
 
         for ( String filename : fileNames )
         {
             files.add( new File( filename ) );
         }
 
         return files;
     }
 
     /**
      * Return a list of files as String depending options.
      * This method use case sensitive file name.
      *
      * @param directory      the directory to scan
      * @param includes       the includes pattern, comma separated
      * @param excludes       the excludes pattern, comma separated
      * @param includeBasedir true to include the base dir in each String of file
      * @return a list of files as String
      * @throws IOException in case of failure.
      */
     @Nonnull public static List<String> getFileNames( @Nonnull File directory, @Nullable String includes,
                                                       @Nullable String excludes, boolean includeBasedir )
         throws IOException
     {
         return getFileNames( directory, includes, excludes, includeBasedir, true );
     }
 
     /**
      * Return a list of files as String depending options.
      *
      * @param directory       the directory to scan
      * @param includes        the includes pattern, comma separated
      * @param excludes        the excludes pattern, comma separated
      * @param includeBasedir  true to include the base dir in each String of file
      * @param isCaseSensitive true if case sensitive
      * @return a list of files as String
      * @throws IOException
      */
     @Nonnull private static List<String> getFileNames( @Nonnull File directory, @Nullable String includes,
                                                        @Nullable String excludes, boolean includeBasedir,
                                                        boolean isCaseSensitive )
         throws IOException
     {
         return getFileAndDirectoryNames( directory, includes, excludes, includeBasedir, isCaseSensitive, true, false );
     }
 
     /**
      * Return a list of directories as String depending options.
      * This method use case sensitive file name.
      *
      * @param directory      the directory to scan
      * @param includes       the includes pattern, comma separated
      * @param excludes       the excludes pattern, comma separated
      * @param includeBasedir true to include the base dir in each String of file
      * @return a list of directories as String
      * @throws IOException in case of failure.
      */
     @Nonnull public static List<String> getDirectoryNames( @Nonnull File directory, @Nullable String includes,
                                                            @Nullable String excludes, boolean includeBasedir )
         throws IOException
     {
         return getDirectoryNames( directory, includes, excludes, includeBasedir, true );
     }
 
     /**
      * Return a list of directories as String depending options.
      *
      * @param directory       the directory to scan
      * @param includes        the includes pattern, comma separated
      * @param excludes        the excludes pattern, comma separated
      * @param includeBasedir  true to include the base dir in each String of file
      * @param isCaseSensitive true if case sensitive
      * @return a list of directories as String
      * @throws IOException in case of failure.
      */
     @Nonnull public static List<String> getDirectoryNames( @Nonnull File directory, @Nullable String includes,
                                                            @Nullable String excludes, boolean includeBasedir,
                                                            boolean isCaseSensitive )
         throws IOException
     {
         return getFileAndDirectoryNames( directory, includes, excludes, includeBasedir, isCaseSensitive, false, true );
     }
 
     /**
      * Return a list of files as String depending options.
      *
      * @param directory       the directory to scan
      * @param includes        the includes pattern, comma separated
      * @param excludes        the excludes pattern, comma separated
      * @param includeBasedir  true to include the base dir in each String of file
      * @param isCaseSensitive true if case sensitive
      * @param getFiles        true if get files
      * @param getDirectories  true if get directories
      * @return a list of files as String
      */
     @Nonnull public static List<String> getFileAndDirectoryNames( File directory, @Nullable String includes,
                                                                   @Nullable String excludes, boolean includeBasedir,
                                                                   boolean isCaseSensitive, boolean getFiles,
                                                                   boolean getDirectories )
     {
         DirectoryScanner scanner = new DirectoryScanner();
 
         scanner.setBasedir( directory );
 
         if ( includes != null )
         {
             scanner.setIncludes( StringUtils.split( includes, "," ) );
         }
 
         if ( excludes != null )
         {
             scanner.setExcludes( StringUtils.split( excludes, "," ) );
         }
 
         scanner.setCaseSensitive( isCaseSensitive );
 
         scanner.scan();
 
         List<String> list = new ArrayList<String>();
 
         if ( getFiles )
         {
             String[] files = scanner.getIncludedFiles();
 
             for ( String file : files )
             {
                 if ( includeBasedir )
                 {
                     list.add( directory + FileUtils.FS + file );
                 }
                 else
                 {
                     list.add( file );
                 }
             }
         }
 
         if ( getDirectories )
         {
             String[] directories = scanner.getIncludedDirectories();
 
             for ( String directory1 : directories )
             {
                 if ( includeBasedir )
                 {
                     list.add( directory + FileUtils.FS + directory1 );
                 }
                 else
                 {
                     list.add( directory1 );
                 }
             }
         }
 
         return list;
     }
 
     /**
      * Copy a directory to an other one.
      *
      * @param sourceDirectory      the source dir
      * @param destinationDirectory the target dir
      * @throws IOException if any
      */
     public static void copyDirectory( @Nonnull File sourceDirectory, @Nonnull File destinationDirectory )
         throws IOException
     {
         copyDirectory( sourceDirectory, destinationDirectory, "**", null );
     }
 
     /**
      * Copy a directory to an other one.
      *
      * @param sourceDirectory      the source dir
      * @param destinationDirectory the target dir
      * @param includes             include pattern
      * @param excludes             exlucde pattern
      * @throws IOException if any
      * @see #getFiles(File, String, String)
      */
     public static void copyDirectory( @Nonnull File sourceDirectory, @Nonnull File destinationDirectory,
                                       @Nullable String includes, @Nullable String excludes )
         throws IOException
     {
         if ( !sourceDirectory.exists() )
         {
             return;
         }
 
         List<File> files = getFiles( sourceDirectory, includes, excludes );
 
         for ( File file : files )
         {
             copyFileToDirectory( file, destinationDirectory );
         }
     }
 
     /**
      * Copies a entire directory structure.
      * <p/>
      * Note:
      * <ul>
      * <li>It will include empty directories.
      * <li>The <code>sourceDirectory</code> must exists.
      * </ul>
      *
      * @param sourceDirectory      the source dir
      * @param destinationDirectory the target dir
      * @throws IOException if any
      */
     public static void copyDirectoryStructure( @Nonnull File sourceDirectory, @Nonnull File destinationDirectory )
         throws IOException
     {
         copyDirectoryStructure( sourceDirectory, destinationDirectory, destinationDirectory, false );
     }
 
     private static void copyDirectoryStructure( @Nonnull File sourceDirectory, @Nonnull File destinationDirectory,
                                                 File rootDestinationDirectory, boolean onlyModifiedFiles )
         throws IOException
     {
         //noinspection ConstantConditions
         if ( sourceDirectory == null )
         {
             throw new IOException( "source directory can't be null." );
         }
 
         //noinspection ConstantConditions
         if ( destinationDirectory == null )
         {
             throw new IOException( "destination directory can't be null." );
         }
 
         if ( sourceDirectory.equals( destinationDirectory ) )
         {
             throw new IOException( "source and destination are the same directory." );
         }
 
         if ( !sourceDirectory.exists() )
         {
             throw new IOException( "Source directory doesn't exists (" + sourceDirectory.getAbsolutePath() + ")." );
         }
 
         File[] files = sourceDirectory.listFiles();
 
         if ( files == null )
         {
             return;
         }
 
         String sourcePath = sourceDirectory.getAbsolutePath();
 
         for ( File file : files )
         {
             if ( file.equals( rootDestinationDirectory ) )
             {
                 // We don't copy the destination directory in itself
                 continue;
             }
 
             String dest = file.getAbsolutePath();
 
             dest = dest.substring( sourcePath.length() + 1 );
 
             File destination = new File( destinationDirectory, dest );
 
             if ( file.isFile() )
             {
                 destination = destination.getParentFile();
 
                 if ( onlyModifiedFiles )
                 {
                     copyFileToDirectoryIfModified( file, destination );
                 }
                 else
                 {
                     copyFileToDirectory( file, destination );
                 }
             }
             else if ( file.isDirectory() )
             {
                 if ( !destination.exists() && !destination.mkdirs() )
                 {
                     throw new IOException(
                         "Could not create destination directory '" + destination.getAbsolutePath() + "'." );
                 }
 
                 copyDirectoryStructure( file, destination, rootDestinationDirectory, onlyModifiedFiles );
             }
             else
             {
                 throw new IOException( "Unknown file type: " + file.getAbsolutePath() );
             }
         }
     }
 
     /**
      * Renames a file, even if that involves crossing file system boundaries.
      * <p/>
      * <p>This will remove <code>to</code> (if it exists), ensure that
      * <code>to</code>'s parent directory exists and move
      * <code>from</code>, which involves deleting <code>from</code> as
      * well.</p>
      *
      * @param from the file to move
      * @param to   the new file name
      * @throws IOException if anything bad happens during this process.
      *                     Note that <code>to</code> may have been deleted already when this happens.
      */
     public static void rename( @Nonnull File from, @Nonnull File to )
         throws IOException
     {
         if ( to.exists() && !deleteLegacyStyle( to ) )
         {
             throw new IOException( "Failed to delete " + to + " while trying to rename " + from );
         }
 
         File parent = to.getParentFile();
         if ( parent != null && !parent.exists() && !parent.mkdirs() )
         {
             throw new IOException( "Failed to create directory " + parent + " while trying to rename " + from );
         }
 
         if ( !from.renameTo( to ) )
         {
             copyFile( from, to );
             if ( !deleteLegacyStyle( from ) )
             {
                 throw new IOException( "Failed to delete " + from + " while trying to rename it." );
             }
         }
     }
 
     /**
      * Create a temporary file in a given directory.
      * <p/>
      * <p>The file denoted by the returned abstract pathname did not
      * exist before this method was invoked, any subsequent invocation
      * of this method will yield a different file name.</p>
      * <p/>
      * The filename is prefixNNNNNsuffix where NNNN is a random number
      * </p>
      * <p>This method is different to {@link File#createTempFile(String, String, File)} of JDK 1.2
      * as it doesn't create the file itself.
      * It uses the location pointed to by java.io.tmpdir
      * when the parentDir attribute is
      * null.</p>
      * <p>To delete automatically the file created by this method, use the
      * {@link File#deleteOnExit()} method.</p>
      *
      * @param prefix    prefix before the random number
      * @param suffix    file extension; include the '.'
      * @param parentDir Directory to create the temporary file in <code>-java.io.tmpdir</code>
      *                  used if not specificed
      * @return a File reference to the new temporary file.
      */
     public static File createTempFile( @Nonnull String prefix, @Nonnull String suffix, @Nullable File parentDir )
     {
         File result;
         String parent = System.getProperty( "java.io.tmpdir" );
         if ( parentDir != null )
         {
             parent = parentDir.getPath();
         }
         DecimalFormat fmt = new DecimalFormat( "#####" );
         SecureRandom secureRandom = new SecureRandom();
         long secureInitializer = secureRandom.nextLong();
         Random rand = new Random( secureInitializer + Runtime.getRuntime().freeMemory() );
         do
         {
             result = new File( parent, prefix + fmt.format( positiveRandom( rand ) ) + suffix );
         }
         while ( result.exists() );
 
         return result;
     }
 
     private static int positiveRandom( Random rand )
     {
         int a = rand.nextInt();
         while ( a == Integer.MIN_VALUE )
         {
             a = rand.nextInt();
         }
         return Math.abs( a );
     }
 
     /**
      * <b>If wrappers is null or empty, the file will be copy only if to.lastModified() < from.lastModified()</b>
      *
      * @param from     the file to copy
      * @param to       the destination file
      * @param encoding the file output encoding (only if wrappers is not empty)
      * @param wrappers array of {@link FilterWrapper}
      * @throws IOException if an IO error occurs during copying or filtering
      */
     public static void copyFile( @Nonnull File from, @Nonnull File to, @Nullable String encoding,
                                  @Nullable FilterWrapper... wrappers )
         throws IOException
     {
         copyFile( from, to, encoding, wrappers, false );
     }
 
     /**
      * Wrapper class for Filter.
      *
      */
     public abstract static class FilterWrapper
     {
         /**
          * @param fileReader {@link Reader}
          * @return The Reader instance.
          */
         public abstract Reader getReader( Reader fileReader );
     }
 
     /**
      * <b>If wrappers is null or empty, the file will be copy only if to.lastModified() < from.lastModified() or if
      * overwrite is true</b>
      *
      * @param from the file to copy
      * @param to the destination file
      * @param encoding the file output encoding (only if wrappers is not empty)
      * @param wrappers array of {@link FilterWrapper}
      * @param overwrite if true and f wrappers is null or empty, the file will be copy enven if to.lastModified() <
      *            from.lastModified()
      * @throws IOException if an IO error occurs during copying or filtering
      */
     public static void copyFile( @Nonnull File from, @Nonnull File to, @Nullable String encoding,
                                  @Nullable FilterWrapper[] wrappers, boolean overwrite )
         throws IOException
     {
         if ( wrappers != null && wrappers.length > 0 )
         {
             // buffer so it isn't reading a byte at a time!
             Reader fileReader = null;
             Writer fileWriter = null;
             try
             {
                 if ( encoding == null || encoding.length() < 1 )
                 {
                     fileReader = new BufferedReader( new FileReader( from ) );
                     fileWriter = new FileWriter( to );
                 }
                 else
                 {
                     FileInputStream instream = new FileInputStream( from );
 
                     FileOutputStream outstream = new FileOutputStream( to );
 
                     fileReader = new BufferedReader( new InputStreamReader( instream, encoding ) );
 
                     fileWriter = new OutputStreamWriter( outstream, encoding );
                 }
 
                 Reader reader = fileReader;
                 for ( FilterWrapper wrapper : wrappers )
                 {
                     reader = wrapper.getReader( reader );
                 }
 
                 IOUtil.copy( reader, fileWriter );
             }
             finally
             {
                 IOUtil.close( fileReader );
                 IOUtil.close( fileWriter );
             }
         }
         else
         {
             if ( to.lastModified() < from.lastModified() || overwrite )
             {
                 copyFile( from, to );
             }
         }
     }
 
     /**
      * Note: the file content is read with platform encoding
      *
      * @param file the file
      * @return a List containing every every line not starting with # and not empty
      * @throws IOException if any
      */
     @Nonnull public static List<String> loadFile( @Nonnull File file )
         throws IOException
     {
         List<String> lines = new ArrayList<String>();
 
         if ( file.exists() )
         {
             FileReader fileReader = new FileReader( file );
             try
             {
                 BufferedReader reader = new BufferedReader( fileReader );
 
                 String line = reader.readLine();
 
                 while ( line != null )
                 {
                     line = line.trim();
 
                     if ( !line.startsWith( "#" ) && line.length() != 0 )
                     {
                         lines.add( line );
                     }
                     line = reader.readLine();
                 }
 
                 reader.close();
             }
             finally
             {
                 fileReader.close();
             }
         }
 
         return lines;
     }
 
     /**
      * For Windows OS, check if the file name contains any of the following characters:
      * <code>":", "*", "?", "\"", "<", ">", "|"</code>
      *
      * @param f not null file
      * @return <code>false</code> if the file path contains any of forbidden Windows characters,
      * <code>true</code> if the Os is not Windows or if the file path respect the Windows constraints.
      * @see #INVALID_CHARACTERS_FOR_WINDOWS_FILE_NAME
      */
     private static boolean isValidWindowsFileName( @Nonnull File f )
     {
         if ( Os.isFamily( Os.FAMILY_WINDOWS ) )
         {
             if ( StringUtils.indexOfAny( f.getName(), INVALID_CHARACTERS_FOR_WINDOWS_FILE_NAME ) != -1 )
             {
                 return false;
             }
 
             if ( f.getParentFile() != null )
             {
                 return isValidWindowsFileName( f.getParentFile() );
             }
         }
 
         return true;
     }
 
     /**
      * Checks whether a given file is a symbolic link.
      *
      * This only works reliably on java7 and higher. For earlier version we use a highly crappy heuristic
      * that mostly does not work.
      * <p>
      * It doesn't really test for symbolic links but whether the canonical and absolute paths of the file are identical
      * - this may lead to false positives on some platforms.
      * </p>
      *
      * @param file the file to check
      * @throws IOException in case of failure.
      * @return true if symbolic link false otherwise.
      *
      */
     public static boolean isSymbolicLink( @Nonnull final File file )
         throws IOException
     {
         if ( Java7Support.isAtLeastJava7() )
         {
             return Java7Support.isSymLink( file );
         }
         return isSymbolicLinkLegacy( file );
     }
 
     /**
      * Checks whether a given file is a symbolic link.
      *
      * @param file the file to check
      * @return true if and only if we reliably can say this is a symlink. This will
      *         always return false for java versions prior to 1.7.
      *
      * @throws IOException in case of failure.
      */
     public static boolean isSymbolicLinkForSure( @Nonnull final File file )
         throws IOException
     {
         return Java7Support.isAtLeastJava7() && Java7Support.isSymLink( file );
     }
 
     /**
      * Checks whether a given file is a symbolic link.
      * <p>
      * It doesn't really test for symbolic links but whether the canonical and absolute
      * paths of the file are identical - this may lead to false positives on some platforms.
      *
      * It also returns true for any file that has been reached via a symbolic link,
      * if you decide to traverse into the symlink.
      *
      * As can be seen from the "return" clause of this method, there is really no
      * guarantee of any sort from this method. Small wonder this ever got used for
      * anything.
      * </p>
      *
      * @param file the file to check
      * @return true if the file is a symbolic link or if we're on some crappy os.
      *         false if the file is not a symlink or we're not able to detect it.
      */
     static boolean isSymbolicLinkLegacy( @Nonnull final File file )
         throws IOException
     {
         final File canonical = new File( file.getCanonicalPath() );
         return !file.getAbsolutePath().equals( canonical.getPath() );
     }
 
 }