Package com.xmlmind.util

Class FileUtil

  • public final class FileUtil
extends Object
    A collection of utility functions (static methods) operating on Files.

    • Field Detail

      • EMPTY_LIST

        public static final File[] EMPTY_LIST
        A ready-to-use empty list of Files.

    • Method Detail

      • fileToURL

        public static URL fileToURL​(File file)
        Converts a File to a file: URL. Ends with a '/' if specified file is a directory.

        On Windows, this function supports UNC filenames. For example, it converts "\\foo\bar\gee.txt" to "file://foo/bar/gee.txt". (Note that URL.openStream works fine on such URL.)

        Parameters:
        file - the file to be converted
        Returns:
        a file: URL
        See Also:
        URLUtil.urlToFile(java.net.URL)

      • getExtension

        public static String getExtension​(File file)
        Returns the extension of specified file. To make it simple, the substring after last '.', not including last '.'.
        • Returns null for "/tmp/test".
        • Returns the empty string for "/tmp/test.".
        • Returns null for "~/.profile".
        • Returns "gz" for "/tmp/test.tar.gz".
        Parameters:
        file - absolute or relative pathname possibly having an extension
        Returns:
        extension if any; null otherwise
        See Also:
        setExtension(java.io.File, java.lang.String)

      • getExtension

        public static String getExtension​(String path)
        Similar to getExtension(File) except that it acts on a filename rather than on a File.

      • indexOfDot

        public static int indexOfDot​(String path,
                             char separatorChar)
        Returns the extension of specified path. To make it simple, the substring after last '.', not including last '.'.
        Parameters:
        path - an absolute or relative path
        separatorChar - the character used to separate path segments
        Returns:
        extension if any; null otherwise

      • setExtension

        public static File setExtension​(File file,
                                String extension)
        Changes the extension of specified file to specified extension. See getExtension(java.io.File) for a description of the extension of a pathname.
        Parameters:
        file - absolute or relative pathname
        extension - new extension. May be null which means: remove the extension.
        Returns:
        a pathname identical to file except that its extension has been changed or removed.

        Returns same pathname if specified pathname ends with File.separator.

      • getRelativePath

        public static String getRelativePath​(File file,
                                     File base)
        Returns the path of specified file relative to specified base.

        Example: returns ../local/bin/html2ps for /usr/local/bin/html2ps relative to /usr/bin/grep.

        Parameters:
        file - a relative or absolute filename
        base - another a relative or absolute filename
        Returns:
        first filename as a filename relative to the second filename. Returns first filename as is, if the relative filename cannot be computed.

      • getVolume

        public static String getVolume​(File file)
        Returns the volume of specified file.

        Returns something like "C:" or "\\server\share" on Windows. Returns "" on all the other platforms.

        Parameters:
        file - a relative or absolute filename
        Returns:
        the volume of specified file or null if specified filename is malformed (e.g. "\\server").

      • checkedDelete

        public static void checkedDelete​(File file)
                          throws IOException
        Like java.io.File.delete() but raises an IOException if this method returns false.
        Throws:
        IOException

      • checkedRename

        public static void checkedRename​(File from,
                                 File to)
                          throws IOException
        Like java.io.File.renameTo() but raises an IOException if this method returns false.
        Throws:
        IOException

      • checkedMkdir

        public static void checkedMkdir​(File dir)
                         throws IOException
        Like java.io.File.mkdir() but raises an IOException if this method returns false.
        Throws:
        IOException

      • checkedMkdirs

        public static void checkedMkdirs​(File dir)
                          throws IOException
        Like java.io.File.mkdirs() but raises an IOException if this method returns false.

        Unlike java.io.File.mkdirs() which does not seem to be thread-safe, this variant is thread-safe.

        Throws:
        IOException

      • checkedListFiles

        public static File[] checkedListFiles​(File dir)
                               throws IOException
        Like java.io.File.listFiles() but raises an IOException if this method returns null.
        Throws:
        IOException

      • checkedListFiles

        public static File[] checkedListFiles​(File dir,
                                      FilenameFilter filter)
                               throws IOException
        Like java.io.File.listFiles(FilenameFilter) but raises an IOException if this method returns null.
        Throws:
        IOException

      • checkedListFiles

        public static File[] checkedListFiles​(File dir,
                                      FileFilter filter)
                               throws IOException
        Like java.io.File.listFiles(FileFilter) but raises an IOException if this method returns null.
        Throws:
        IOException

      • checkedList

        public static String[] checkedList​(File dir)
                            throws IOException
        Like java.io.File.list() but raises an IOException if this method returns null.
        Throws:
        IOException

      • checkedSetLastModified

        public static void checkedSetLastModified​(File file,
                                          long date)
                                   throws IOException
        Like java.io.File.setLastModified() but raises an IOException if this method returns false.
        Throws:
        IOException

      • checkedCreateNewFile

        public static void checkedCreateNewFile​(File file)
                                 throws IOException
        Like java.io.File.createNewFile() but raises an IOException if this method returns false.
        Throws:
        IOException

      • createTempDirectory

        public static File createTempDirectory​(String prefix,
                                       File directory)
                                throws IOException
        Create a temporary directory.
        Parameters:
        prefix - the prefix string to be used in generating the diretory name; must be at least three characters long
        directory - the directory in which the new directory is to be created, or null if the default temporary-file directory is to be used
        Returns:
        the newly created temporary directory
        Throws:
        IOException - if the temporary directory cannot be created

      • formatFileSize

        public static String formatFileSize​(long fileSize,
                                    Locale locale)
        Returns a localized, formatted, form of specified file size.

        For example, returns "56.5Gb" when passed 59279560 in the US locale.

      • emptyDir

        public static void emptyDir​(File dir)
                     throws IOException
        Removes all the files contained in specified directory.
        Parameters:
        dir - directory to be made empty
        Throws:
        IOException - if, for any reason, the directory cannot be made empty

      • doEmptyDir

        public static boolean doEmptyDir​(File dir)
        Removes all the files contained in specified directory.
        Parameters:
        dir - directory to be made empty
        Returns:
        true if the directory has been made empty; false otherwise

      • isEmptyDir

        public static boolean isEmptyDir​(File file)
        Returns true if specified file exists, is a directory and is empty. Returns false otherwise.
        See Also:
        checkIsEmptyDir(java.io.File)

      • checkIsEmptyDir

        public static void checkIsEmptyDir​(File file)
                            throws IOException
        Check whether if specified file exists, is a directory and is empty. If this is not the case, throw an IOException.
        Throws:
        IOException
        See Also:
        isEmptyDir(java.io.File)

      • deleteFileOrDir

        public static void deleteFileOrDir​(File fileOrDir,
                                   Console console)
                            throws IOException
        Deletes specified file or directory. A directory is recursively deleted.
        Parameters:
        fileOrDir - file or directory to be deleted
        console - a message describing the operation is displayed on this console. May be null.
        Throws:
        IOException - if, for any reason, specified file or directory cannot be deleted

      • deleteDir

        public static void deleteDir​(File dir,
                             Console console)
                      throws IOException
        Deletes specified directory. A directory is recursively deleted.
        Parameters:
        dir - directory to be deleted
        console - a message describing the operation is displayed on this console. May be null.
        Throws:
        IOException - if, for any reason, specified directory cannot be deleted

      • deleteFile

        public static void deleteFile​(File file,
                              Console console)
                       throws IOException
        Deletes specified file (not a directory).
        Parameters:
        file - file to be deleted
        console - a message describing the operation is displayed on this console. May be null.
        Throws:
        IOException - if, for any reason, specified file cannot be deleted

      • deleteFileOrDir

        public static void deleteFileOrDir​(File fileOrDir)
                            throws IOException
        Deletes specified file or directory. A directory is recursively deleted.
        Parameters:
        fileOrDir - file or directory to be deleted
        Throws:
        IOException - if, for any reason, specified file or directory cannot be deleted

      • doDeleteFileOrDir

        public static boolean doDeleteFileOrDir​(File fileOrDir)
        Deletes specified file or directory. A directory is recursively deleted.
        Parameters:
        fileOrDir - file or directory to be deleted
        Returns:
        true if specified file or directory has been deleted; false otherwise

      • deleteDir

        public static void deleteDir​(File dir)
                      throws IOException
        Deletes specified directory. A directory is recursively deleted.
        Parameters:
        dir - directory to be deleted
        Throws:
        IOException - if, for any reason, specified directory cannot be deleted

      • deleteFile

        public static void deleteFile​(File file)
                       throws IOException
        Deletes specified file (not a directory).
        Parameters:
        file - file to be deleted
        Throws:
        IOException - if, for any reason, specified file cannot be deleted

      • copyFileOrDir

        public static void copyFileOrDir​(File srcFileOrDir,
                                 File dstFileOrDir,
                                 boolean sameDate,
                                 Console console)
                          throws IOException
        Copies specified file or directory. Directories are recursively copied.

        If a directory is to be copied, the target of the copy operation must not exist. If a file is to be copied and the target of the copy operation already exists, this target is overwritten.

        Parameters:
        srcFileOrDir - file or directory to be copied
        dstFileOrDir - target of the copy operation
        sameDate - if true, a copied file has the same last modified date as the original file. If false, a copied file has the date of its creation as its last modified date.
        console - a message describing the operation is displayed on this console. May be null.
        Throws:
        IOException - if, for any reason, specified file or directory cannot be copied

      • copyDir

        public static void copyDir​(File srcDir,
                           File dstDir,
                           boolean sameDate,
                           Console console)
                    throws IOException
        Recursively copies specified directory. The target of the copy operation must not exist.
        Parameters:
        srcDir - directory to be copied
        dstDir - target of the copy operation
        sameDate - if true, a copied file has the same last modified date as the original file. If false, a copied file has the date of its creation as its last modified date.
        console - a message describing the operation is displayed on this console. May be null.
        Throws:
        IOException - if, for any reason, specified directory cannot be copied

      • copyFile

        public static void copyFile​(File srcFile,
                            File dstFile,
                            boolean sameDate,
                            Console console)
                     throws IOException
        Copies specified file (not a directory). If the target of the copy operation already exists, this target is overwritten.
        Parameters:
        srcFile - file to be copied
        dstFile - target of the copy operation
        sameDate - if true, a copied file has the same last modified date as the original file. If false, a copied file has the date of its creation as its last modified date.
        console - a message describing the operation is displayed on this console. May be null.
        Throws:
        IOException - if, for any reason, specified file cannot be copied

      • copyFileOrDir

        public static void copyFileOrDir​(File srcFileOrDir,
                                 File dstFileOrDir,
                                 boolean sameDate)
                          throws IOException
        Copies specified file or directory. Directories are recursively copied.

        If a directory is to be copied, the target of the copy operation must not exist. If a file is to be copied and the target of the copy operation already exists, this target is overwritten.

        Parameters:
        srcFileOrDir - file or directory to be copied
        dstFileOrDir - target of the copy operation
        sameDate - if true, a copied file has the same last modified date as the original file. If false, a copied file has the date of its creation as its last modified date.
        Throws:
        IOException - if, for any reason, specified file or directory cannot be copied

      • copyDir

        public static void copyDir​(File srcDir,
                           File dstDir,
                           boolean sameDate)
                    throws IOException
        Recursively copies specified directory. The target of the copy operation must not exist.
        Parameters:
        srcDir - directory to be copied
        dstDir - target of the copy operation
        sameDate - if true, a copied file has the same last modified date as the original file. If false, a copied file has the date of its creation as its last modified date.
        Throws:
        IOException - if, for any reason, specified directory cannot be copied

      • copyFile

        public static void copyFile​(File srcFile,
                            File dstFile,
                            boolean sameDate)
                     throws IOException
        Copies specified file (not a directory). If the target of the copy operation already exists, this target is overwritten.
        Parameters:
        srcFile - file to be copied
        dstFile - target of the copy operation
        sameDate - if true, a copied file has the same last modified date as the original file. If false, a copied file has the date of its creation as its last modified date.
        Throws:
        IOException - if, for any reason, specified file cannot be copied

      • copyFile

        public static void copyFile​(File srcFile,
                            File dstFile)
                     throws IOException
        Copies specified file (not a directory). If the target of the copy operation already exists, this target is overwritten.
        Parameters:
        srcFile - file to be copied
        dstFile - target of the copy operation
        Throws:
        IOException - if, for any reason, specified file cannot be copied

      • copyFile

        public static void copyFile​(URL url,
                            File dstFile)
                     throws IOException
        Copies the contents of specified URL to specified file.
        Parameters:
        url - URL to be copied
        dstFile - destination file
        Throws:
        IOException - if an I/O problem occurs

      • copyFile

        public static void copyFile​(InputStream src,
                            File dstFile)
                     throws IOException
        Copies specified source to specified file.
        Parameters:
        src - source stream
        dstFile - destination file
        Throws:
        IOException - if an I/O problem occurs

      • copyFile

        public static void copyFile​(File srcFile,
                            OutputStream dst)
                     throws IOException
        Copies specified file to specified destination.
        Parameters:
        srcFile - source file
        dst - destination stream
        Throws:
        IOException - if an I/O problem occurs

      • loadString

        public static String loadString​(File file)
                         throws IOException
        Loads the content of a text file. The encoding of the text is assumed to be the native encoding of the platform.
        Parameters:
        file - the text file
        Returns:
        the loaded String
        Throws:
        IOException - if there is an I/O problem

      • loadString

        public static String loadString​(File file,
                                String charsetName)
                         throws IOException
        Loads the content of a text file. The encoding of the text is assumed to be the native encoding of the platform.
        Parameters:
        file - the text file
        charsetName - the IANA charset of the text source if known; null may be used to specify the native encoding of the platform
        Returns:
        the loaded String
        Throws:
        IOException - if there is an I/O problem

      • loadString

        public static String loadString​(InputStream stream,
                                String charsetName)
                         throws IOException
        Loads text using specified stream.
        Parameters:
        stream - the text source
        charsetName - the IANA charset of the text source if known; null may be used to specify the native encoding of the platform
        Returns:
        the loaded String
        Throws:
        IOException - if there is an I/O problem

      • loadString

        public static String loadString​(Reader in)
                         throws IOException
        Loads text using specified reader.
        Parameters:
        in - the text source
        Returns:
        the loaded String
        Throws:
        IOException - if there is an I/O problem

      • saveString

        public static void saveString​(String string,
                              File file)
                       throws IOException
        Saves some text to a file.
        Parameters:
        string - the text to be saved
        file - the destination file
        Throws:
        IOException - if there is an I/O problem

      • saveString

        public static void saveString​(String string,
                              File file,
                              String charsetName)
                       throws IOException
        Saves some text to a file.
        Parameters:
        string - the text to be saved
        file - the destination file
        charsetName - the IANA charset of the saved file; null may be used to specify the native encoding of the platform
        Throws:
        IOException - if there is an I/O problem

      • saveString

        public static void saveString​(String string,
                              OutputStream stream,
                              String charsetName)
                       throws IOException
        Saves some text to an OutputStream.
        Parameters:
        string - the text to be saved
        stream - the text sink
        charsetName - the IANA charset of the saved characters; null may be used to specify the native encoding of the platform
        Throws:
        IOException - if there is an I/O problem

      • isGzipped

        public static final boolean isGzipped​(byte[] bytes)
        Tests if specified data has been compressed using gzip.

      • loadBytes

        public static byte[] loadBytes​(File file)
                        throws IOException
        Loads the content of a binary file.
        Parameters:
        file - the binary file
        Returns:
        the loaded bytes
        Throws:
        IOException - if there is an I/O problem

      • loadBytes

        public static byte[] loadBytes​(InputStream in)
                        throws IOException
        Loads the content of an InputStream returning binary data.
        Parameters:
        in - the binary data source
        Returns:
        the loaded bytes
        Throws:
        IOException - if there is an I/O problem

      • saveBytes

        public static void saveBytes​(byte[] bytes,
                             File file)
                      throws IOException
        Saves binary data to a file.
        Parameters:
        bytes - the binary data to be saved
        file - the destination file
        Throws:
        IOException - if there is an I/O problem