Package fr.coppernic.gradle.utils

Class FilenameUtils

  • public class FilenameUtils
extends java.lang.Object
    General filename and filepath manipulation utilities.

    When dealing with filenames you can hit problems when moving from a Windows based development machine to a Unix based production machine. This class aims to help avoid those problems. NOTE: You may be able to avoid using this class entirely simply by using JDK File objects and the two argument constructor File(File,String).

    Most methods on this class are designed to work the same on both Unix and Windows. Those that don't include 'System', 'Unix' or 'Windows' in their name.

    Most methods recognise both separators (forward and back), and both sets of prefixes. See the javadoc of each method for details.

    This class defines six components within a filename (example C:\dev\project\file.txt):

    • the prefix - C:\
    • the path - dev\project\
    • the full path - C:\dev\project\
    • the name - file.txt
    • the base name - file
    • the extension - txt
    Note that this class works best if directory filenames end with a separator. If you omit the last separator, it is impossible to determine if the filename corresponds to a file or a directory. As a result, we have chosen to say it corresponds to a file.

    This class only supports Unix and Windows style names. Prefixes are matched as follows: 

     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

 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)
    Both prefix styles are matched always, irrespective of the machine that you are currently running on.

    Origin of code: Excalibur, Alexandria, Tomcat, Commons-Utils.

    Since:
    Commons IO 1.1

    • Constructor Summary

      Constructors 
      Constructor Description
      FilenameUtils()
      Instances should NOT be constructed in standard programming.

    • Method Summary

      All Methods Static Methods Concrete Methods 
      Modifier and Type Method Description
      static java.lang.String concat​(java.lang.String basePath, java.lang.String fullFilenameToAdd)
      Concatenates a filename to a base path using normal command line style rules.
      static java.lang.String getBaseName​(java.lang.String filename)
      Gets the base name, minus the full path and extension, from a full filename.
      static java.lang.String getExtension​(java.lang.String filename)
      Gets the extension of a filename.
      static java.lang.String getFullPath​(java.lang.String filename)
      Gets the full path from a full filename, which is the prefix + path.
      static java.lang.String getFullPathNoEndSeparator​(java.lang.String filename)
      Gets the full path from a full filename, which is the prefix + path, and also excluding the final directory separator.
      static java.lang.String getName​(java.lang.String filename)
      Gets the name minus the path from a full filename.
      static java.lang.String getPath​(java.lang.String filename)
      Gets the path from a full filename, which excludes the prefix.
      static java.lang.String getPathNoEndSeparator​(java.lang.String filename)
      Gets the path from a full filename, which excludes the prefix, and also excluding the final directory separator.
      static java.lang.String getPrefix​(java.lang.String filename)
      Gets the prefix from a full filename, such as C:/ or ~/.
      static int getPrefixLength​(java.lang.String filename)
      Returns the length of the filename prefix, such as C:/ or ~/.
      static int indexOfExtension​(java.lang.String filename)
      Returns the index of the last extension separator character, which is a dot.
      static int indexOfLastSeparator​(java.lang.String filename)
      Returns the index of the last directory separator character.
      static boolean isExtension​(java.lang.String filename, java.lang.String extension)
      Checks whether the extension of the filename is that specified.
      static boolean isExtension​(java.lang.String filename, java.lang.String[] extensions)
      Checks whether the extension of the filename is one of those specified.
      static boolean isExtension​(java.lang.String filename, java.util.Collection extensions)
      Checks whether the extension of the filename is one of those specified.
      static java.lang.String normalize​(java.lang.String filename)
      Normalizes a path, removing double and single dot path steps.
      static java.lang.String normalizeNoEndSeparator​(java.lang.String filename)
      Normalizes a path, removing double and single dot path steps, and removing any final directory separator.
      static java.lang.String removeExtension​(java.lang.String filename)
      Removes the extension from a filename.
      static java.lang.String separatorsToSystem​(java.lang.String path)
      Converts all separators to the system separator.
      static java.lang.String separatorsToUnix​(java.lang.String path)
      Converts all separators to the Unix separator of forward slash.
      static java.lang.String separatorsToWindows​(java.lang.String path)
      Converts all separators to the Windows separator of backslash.

      • Methods inherited from class java.lang.Object

        clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

    • Field Detail

      • EXTENSION_SEPARATOR

        public static final char EXTENSION_SEPARATOR
        The extension separator character.
        Since:
        Commons IO 1.4
        See Also:
        Constant Field Values

      • EXTENSION_SEPARATOR_STR

        public static final java.lang.String EXTENSION_SEPARATOR_STR
        The extension separator String.
        Since:
        Commons IO 1.4

    • Constructor Detail

      • FilenameUtils

        public FilenameUtils()
        Instances should NOT be constructed in standard programming.

    • Method Detail

      • normalize

        public static java.lang.String normalize​(java.lang.String filename)
        Normalizes a path, removing double and single dot path steps.

        This method normalizes a path to a standard format. The input may contain separators in either Unix or Windows format. The output will contain separators in the format of the system.

        A trailing slash will be retained. A double slash will be merged to a single slash (but UNC names are handled). A single dot path segment will be removed. A double dot will cause that path segment and the one before to be removed. If the double dot has no parent path segment to work with, null is returned.

        The output will be the same on both Unix and Windows except for the separator character. 

         /foo//               --   /foo/
 /foo/./              --   /foo/
 /foo/../bar          --   /bar
 /foo/../bar/         --   /bar/
 /foo/../bar/../baz   --   /baz
 //foo//./bar         --   /foo/bar
 /../                 --   null
 ../foo               --   null
 foo/bar/..           --   foo/
 foo/../../bar        --   null
 foo/../bar           --   bar
 //server/foo/../bar  --   //server/bar
 //server/../bar      --   null
 C:\foo\..\bar        --   C:\bar
 C:\..\bar            --   null
 ~/foo/../bar/        --   ~/bar/
 ~/../bar             --   null
        (Note the file separator returned will be correct for Windows/Unix)
        Parameters:
        filename - the filename to normalize, null returns null
        Returns:
        the normalized filename, or null if invalid

      • normalizeNoEndSeparator

        public static java.lang.String normalizeNoEndSeparator​(java.lang.String filename)
        Normalizes a path, removing double and single dot path steps, and removing any final directory separator.

        This method normalizes a path to a standard format. The input may contain separators in either Unix or Windows format. The output will contain separators in the format of the system.

        A trailing slash will be removed. A double slash will be merged to a single slash (but UNC names are handled). A single dot path segment will be removed. A double dot will cause that path segment and the one before to be removed. If the double dot has no parent path segment to work with, null is returned.

        The output will be the same on both Unix and Windows except for the separator character. 

         /foo//               --   /foo
 /foo/./              --   /foo
 /foo/../bar          --   /bar
 /foo/../bar/         --   /bar
 /foo/../bar/../baz   --   /baz
 //foo//./bar         --   /foo/bar
 /../                 --   null
 ../foo               --   null
 foo/bar/..           --   foo
 foo/../../bar        --   null
 foo/../bar           --   bar
 //server/foo/../bar  --   //server/bar
 //server/../bar      --   null
 C:\foo\..\bar        --   C:\bar
 C:\..\bar            --   null
 ~/foo/../bar/        --   ~/bar
 ~/../bar             --   null
        (Note the file separator returned will be correct for Windows/Unix)
        Parameters:
        filename - the filename to normalize, null returns null
        Returns:
        the normalized filename, or null if invalid

      • concat

        public static java.lang.String concat​(java.lang.String basePath,
                                      java.lang.String fullFilenameToAdd)
        Concatenates a filename to a base path using normal command line style rules.

        The effect is equivalent to resultant directory after changing directory to the first argument, followed by changing directory to the second argument.

        The first argument is the base path, the second is the path to concatenate. The returned path is always normalized via normalize(String), thus .. is handled.

        If pathToAdd is absolute (has an absolute prefix), then it will be normalized and returned. Otherwise, the paths will be joined, normalized and returned.

        The output will be the same on both Unix and Windows except for the separator character. 

         /foo/ + bar          --   /foo/bar
 /foo + bar           --   /foo/bar
 /foo + /bar          --   /bar
 /foo + C:/bar        --   C:/bar
 /foo + C:bar         --   C:bar (*)
 /foo/a/ + ../bar     --   foo/bar
 /foo/ + ../../bar    --   null
 /foo/ + /bar         --   /bar
 /foo/.. + /bar       --   /bar
 /foo + bar/c.txt     --   /foo/bar/c.txt
 /foo/c.txt + bar     --   /foo/c.txt/bar (!)
        (*) Note that the Windows relative drive prefix is unreliable when used with this method. (!) Note that the first parameter must be a path. If it ends with a name, then the name will be built into the concatenated path. If this might be a problem, use getFullPath(String) on the base path argument.
        Parameters:
        basePath - the base path to attach to, always treated as a path
        fullFilenameToAdd - the filename (or path) to attach to the base
        Returns:
        the concatenated path, or null if invalid

      • separatorsToUnix

        public static java.lang.String separatorsToUnix​(java.lang.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

      • separatorsToWindows

        public static java.lang.String separatorsToWindows​(java.lang.String path)
        Converts all separators to the Windows separator of backslash.
        Parameters:
        path - the path to be changed, null ignored
        Returns:
        the updated path

      • separatorsToSystem

        public static java.lang.String separatorsToSystem​(java.lang.String path)
        Converts all separators to the system separator.
        Parameters:
        path - the path to be changed, null ignored
        Returns:
        the updated path

      • getPrefixLength

        public static int getPrefixLength​(java.lang.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

 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)

        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.

        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​(java.lang.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​(java.lang.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 path separator in, null returns -1
        Returns:
        the index of the last separator character, or -1 if there is no such character

      • getPrefix

        public static java.lang.String getPrefix​(java.lang.String filename)
        Gets the prefix from a full filename, such as C:/ or ~/.

        This method will handle a file in either Unix or Windows format. The prefix includes the first slash in the full filename where applicable. 

         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

 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)

        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.

        Parameters:
        filename - the filename to query, null returns null
        Returns:
        the prefix of the file, null if invalid

      • getPath

        public static java.lang.String getPath​(java.lang.String filename)
        Gets the path from a full filename, which excludes the prefix.

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

        This method drops the prefix from the result. See getFullPath(String) for the method that retains the prefix.

        Parameters:
        filename - the filename to query, null returns null
        Returns:
        the path of the file, an empty string if none exists, null if invalid

      • getPathNoEndSeparator

        public static java.lang.String getPathNoEndSeparator​(java.lang.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.

        This method drops the prefix from the result. See getFullPathNoEndSeparator(String) for the method that retains the prefix.

        Parameters:
        filename - the filename to query, null returns null
        Returns:
        the path of the file, an empty string if none exists, null if invalid

      • getFullPath

        public static java.lang.String getFullPath​(java.lang.String filename)
        Gets the full path from a full filename, which is the prefix + path.

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

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

        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

      • getFullPathNoEndSeparator

        public static java.lang.String getFullPathNoEndSeparator​(java.lang.String filename)
        Gets the full path from a full filename, which is the prefix + path, 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 -- C:\a\b
 ~/a/b/c.txt  -- ~/a/b
 a.txt        -- ""
 a/b/c        -- a/b
 a/b/c/       -- a/b/c
 C:           -- C:
 C:\          -- C:\
 ~            -- ~
 ~/           -- ~
 ~user        -- ~user
 ~user/       -- ~user

        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

      • getName

        public static java.lang.String getName​(java.lang.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

      • getBaseName

        public static java.lang.String getBaseName​(java.lang.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

      • getExtension

        public static java.lang.String getExtension​(java.lang.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.

      • removeExtension

        public static java.lang.String removeExtension​(java.lang.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

      • isExtension

        public static boolean isExtension​(java.lang.String filename,
                                  java.lang.String extension)
        Checks whether the extension of the filename is that specified.

        This method obtains the extension as the textual part of the filename after the last dot. There must be no directory separator after the dot. The extension check is case-sensitive on all platforms.

        Parameters:
        filename - the filename to query, null returns false
        extension - the extension to check for, null or empty checks for no extension
        Returns:
        true if the filename has the specified extension

      • isExtension

        public static boolean isExtension​(java.lang.String filename,
                                  java.lang.String[] extensions)
        Checks whether the extension of the filename is one of those specified.

        This method obtains the extension as the textual part of the filename after the last dot. There must be no directory separator after the dot. The extension check is case-sensitive on all platforms.

        Parameters:
        filename - the filename to query, null returns false
        extensions - the extensions to check for, null checks for no extension
        Returns:
        true if the filename is one of the extensions

      • isExtension

        public static boolean isExtension​(java.lang.String filename,
                                  java.util.Collection extensions)
        Checks whether the extension of the filename is one of those specified.

        This method obtains the extension as the textual part of the filename after the last dot. There must be no directory separator after the dot. The extension check is case-sensitive on all platforms.

        Parameters:
        filename - the filename to query, null returns false
        extensions - the extensions to check for, null checks for no extension
        Returns:
        true if the filename is one of the extensions