Package com.tangosol.io

Class FileHelper

  • public class FileHelper
extends Object
    A Collection of helper methods for files.
    Author:
    jh 2012.07.13

    • Constructor Detail

      • FileHelper

        public FileHelper()

    • Method Detail

      • toFilename

        public static String toFilename​(String sName)
        Given a string, return a derivative version that is safe to use for a filename.
        Parameters:
        sName - the string
        Returns:
        a derivative of the given string that is safe to use as a filename (may be the same as the string supplied)

      • getPath

        public static String getPath​(File file)
        Return the path of a file.

        The implementation attempts to get the canonical path and iff this call abruptly fails is the absolute path returned.

        Parameters:
        file - the File to be interrogated to return the path
        Returns:
        the path of the provided file

      • ensureDir

        public static File ensureDir​(File file)
                      throws IOException
        Validate that the given File represents a directory, creating it if it doesn't already exist.
        Parameters:
        file - the File to check
        Returns:
        the validated File
        Throws:
        IOException - on error creating the directory

      • validateDir

        public static void validateDir​(File file)
                        throws IOException
        Validate that the given File exists and represents a directory.
        Parameters:
        file - the File to check
        Throws:
        IOException - if the given File doesn't exist or doesn't represent a directory

      • copyDir

        public static void copyDir​(File fileDirFrom,
                           File fileDirTo)
                    throws IOException
        Create a deep copy of the specified directory into the specified target directory.
        Parameters:
        fileDirFrom - the directory to copy from
        fileDirTo - the directory to copy into
        Throws:
        IOException - if an error occurred copying the directory

      • deleteDir

        public static void deleteDir​(File fileDir)
                      throws IOException
        Delete a directory recursively.
        Parameters:
        fileDir - directory to delete
        Throws:
        IOException - if an error occurred deleting the directory

      • deleteDirSilent

        public static void deleteDirSilent​(File fileDir)
        Recursively delete a directory suppressing any raised exceptions.
        Parameters:
        fileDir - directory to delete

      • moveDir

        public static void moveDir​(File fileDirFrom,
                           File fileDirTo)
                    throws IOException
        Move the specified directory to the specified destination path.
        Parameters:
        fileDirFrom - the directory to move
        fileDirTo - the destination path
        Throws:
        IOException - if an error occurred moving the directory

      • createTempDir

        public static File createTempDir()
                          throws IOException
        Create a unique temporary directory.
        Returns:
        a unique temporary directory
        Throws:
        IOException

      • sizeDir

        public static long sizeDir​(File fileDir)
        Return the approximate disk usage in bytes for a given directory. Note the size may differ from the actual size on the file system due to compression, support for sparse files, or other reasons.
        Parameters:
        fileDir - the directory to size
        Returns:
        the number of total bytes used by the files in the directory

      • copyFile

        public static void copyFile​(File fileFrom,
                            File fileTo)
                     throws IOException
        Copy the specified file according to the source and destination File objects preserving the time-stamp of the source.
        Parameters:
        fileFrom - the File to copy from
        fileTo - the File to copy to
        Throws:
        IOException - if an error occurred copying the file

      • moveFile

        public static void moveFile​(File fileFrom,
                            File fileTo)
                     throws IOException
        Move the specified file to the specified destination path.
        Parameters:
        fileFrom - the file to move
        fileTo - the destination path
        Throws:
        IOException - if an error occurred moving the file

      • lockFile

        public static FileLock lockFile​(File file)
        Obtain an exclusive lock on the specified file. The lock should be released with the unlockFile method.
        Parameters:
        file - the file to lock
        Returns:
        a FileLock if an exclusive lock was obtained, null otherwise

      • separatorsToUnix

        public static String separatorsToUnix​(String path)
        Converts all separators to the Unix separator of forward slash.
        Parameters:
        path - the path to be changed, null ignored
        Returns:
        the updated path

      • getPrefixLength

        public static int getPrefixLength​(String filename)
        Returns the length of the filename prefix, such as C:/ or ~/.

        This method will handle a file in either Unix or Windows format.

        The prefix length includes the first slash in the full filename if applicable. Thus, it is possible that the length returned is greater than the length of the input string. 

         Windows:
 a\b\c.txt           --> ""          --> relative
 \a\b\c.txt          --> "\"         --> current drive absolute
 C:a\b\c.txt         --> "C:"        --> drive relative
 C:\a\b\c.txt        --> "C:\"       --> absolute
 \\server\a\b\c.txt  --> "\\server\" --> UNC
 \\\a\b\c.txt        -->  error, length = -1

 Unix:
 a/b/c.txt           --> ""          --> relative
 /a/b/c.txt          --> "/"         --> absolute
 ~/a/b/c.txt         --> "~/"        --> current user
 ~                   --> "~/"        --> current user (slash added)
 ~user/a/b/c.txt     --> "~user/"    --> named user
 ~user               --> "~user/"    --> named user (slash added)
 //server/a/b/c.txt  --> "//server/"
 ///a/b/c.txt        --> error, length = -1

        The output will be the same irrespective of the machine that the code is running on. ie. both Unix and Windows prefixes are matched regardless.

        Note that a leading // (or \\) is used to indicate a UNC name on Windows. These must be followed by a server name, so double-slashes are not collapsed to a single slash at the start of the filename.

        Parameters:
        filename - the filename to find the prefix in, null returns -1
        Returns:
        the length of the prefix, -1 if invalid or null

      • indexOfLastSeparator

        public static int indexOfLastSeparator​(String filename)
        Returns the index of the last directory separator character.

        This method will handle a file in either Unix or Windows format. The position of the last forward or backslash is returned.

        The output will be the same irrespective of the machine that the code is running on.

        Parameters:
        filename - the filename to find the last path separator in, null returns -1
        Returns:
        the index of the last separator character, or -1 if there is no such character

      • indexOfExtension

        public static int indexOfExtension​(String filename)
        Returns the index of the last extension separator character, which is a dot.

        This method also checks that there is no directory separator after the last dot. To do this it uses indexOfLastSeparator(String) which will handle a file in either Unix or Windows format.

        The output will be the same irrespective of the machine that the code is running on.

        Parameters:
        filename - the filename to find the last extension separator in, null returns -1
        Returns:
        the index of the last extension separator character, or -1 if there is no such character

      • getPathNoEndSeparator

        public static String getPathNoEndSeparator​(String filename)
        Gets the path from a full filename, which excludes the prefix, and also excluding the final directory separator.

        This method will handle a file in either Unix or Windows format. The method is entirely text based, and returns the text before the last forward or backslash. 

         C:\a\b\c.txt --> a\b
 ~/a/b/c.txt  --> a/b
 a.txt        --> ""
 a/b/c        --> a/b
 a/b/c/       --> a/b/c

        The output will be the same irrespective of the machine that the code is running on.

        Parameters:
        filename - the filename to query, null returns null
        Returns:
        the path of the file, an empty string if none exists, null if invalid. Null bytes inside string will be removed

      • getName

        public static String getName​(String filename)
        Gets the name minus the path from a full filename.

        This method will handle a file in either Unix or Windows format. The text after the last forward or backslash is returned. 

         a/b/c.txt --> c.txt
 a.txt     --> a.txt
 a/b/c     --> c
 a/b/c/    --> ""

        The output will be the same irrespective of the machine that the code is running on.

        Parameters:
        filename - the filename to query, null returns null
        Returns:
        the name of the file without the path, or an empty string if none exists. Null bytes inside string will be removed

      • getBaseName

        public static String getBaseName​(String filename)
        Gets the base name, minus the full path and extension, from a full filename.

        This method will handle a file in either Unix or Windows format. The text after the last forward or backslash and before the last dot is returned. 

         a/b/c.txt --> c
 a.txt     --> a
 a/b/c     --> c
 a/b/c/    --> ""

        The output will be the same irrespective of the machine that the code is running on.

        Parameters:
        filename - the filename to query, null returns null
        Returns:
        the name of the file without the path, or an empty string if none exists. Null bytes inside string will be removed

      • getExtension

        public static String getExtension​(String filename)
        Gets the extension of a filename.

        This method returns the textual part of the filename after the last dot. There must be no directory separator after the dot. 

         foo.txt      --> "txt"
 a/b/c.jpg    --> "jpg"
 a/b.txt/c    --> ""
 a/b/c        --> ""

        The output will be the same irrespective of the machine that the code is running on.

        Parameters:
        filename - the filename to retrieve the extension of.
        Returns:
        the extension of the file or an empty string if none exists or null if the filename is null.

      • removeExtension

        public static String removeExtension​(String filename)
        Removes the extension from a filename.

        This method returns the textual part of the filename before the last dot. There must be no directory separator after the dot. 

         foo.txt    --> foo
 a\b\c.jpg  --> a\b\c
 a\b\c      --> a\b\c
 a.b\c      --> a.b\c

        The output will be the same irrespective of the machine that the code is running on.

        Parameters:
        filename - the filename to query, null returns null
        Returns:
        the filename minus the extension