Package org.apache.commons.io

Enum FileSystem

  • All Implemented Interfaces:
    java.io.Serializable, java.lang.Comparable<FileSystem>
    public enum FileSystem
extends java.lang.Enum<FileSystem>
    Abstracts an OS' file system details, currently supporting the single use case of converting a file name String to a legal file name with toLegalFileName(String, char).

    The starting point of any operation is getCurrent() which gets you the enum for the file system that matches the OS hosting the running JVM.

    Since:
    2.7

    • Enum Constant Summary

      Enum Constants 
      Enum Constant Description
      GENERIC
      Generic file system.
      LINUX
      Linux file system.
      MAC_OSX
      MacOS file system.
      WINDOWS
      Windows file system.

    • Method Summary

      All Methods Static Methods Instance Methods Concrete Methods 
      Modifier and Type Method Description
      int getBlockSize()
      Gets the file allocation block size in bytes.
      static FileSystem getCurrent()
      Gets the current file system.
      char[] getIllegalFileNameChars()
      Gets a cloned copy of the illegal characters for this file system.
      int[] getIllegalFileNameCodePoints()
      Gets a cloned copy of the illegal code points for this file system.
      int getMaxFileNameLength()
      Gets the maximum length for file names (excluding any folder path).
      int getMaxPathLength()
      Gets the maximum length for file paths (may include folders).
      char getNameSeparator()
      Gets the name separator, '\\' on Windows, '/' on Linux.
      java.lang.String[] getReservedFileNames()
      Gets a cloned copy of the reserved file names.
      boolean isCasePreserving()
      Tests whether this file system preserves case.
      boolean isCaseSensitive()
      Tests whether this file system is case-sensitive.
      boolean isLegalFileName​(java.lang.CharSequence candidate)
      Tests if a candidate file name (without a path) is a legal file name.
      boolean isLegalFileName​(java.lang.CharSequence candidate, java.nio.charset.Charset charset)
      Tests if a candidate file name (without a path) is a legal file name.
      boolean isReservedFileName​(java.lang.CharSequence candidate)
      Tests whether the given string is a reserved file name.
      java.lang.String normalizeSeparators​(java.lang.String path)
      Converts all separators to the Windows separator of backslash.
      boolean supportsDriveLetter()
      Tests whether this file system support driver letters.
      java.lang.String toLegalFileName​(java.lang.CharSequence candidate, char replacement, java.nio.charset.Charset charset)
      Converts a candidate file name (without a path) to a legal file name.
      java.lang.String toLegalFileName​(java.lang.String candidate, char replacement)
      Converts a candidate file name (without a path) to a legal file name.
      static FileSystem valueOf​(java.lang.String name)
      Returns the enum constant of this type with the specified name.
      static FileSystem[] values()
      Returns an array containing the constants of this enum type, in the order they are declared.

      • Methods inherited from class java.lang.Enum

        clone, compareTo, equals, finalize, getDeclaringClass, hashCode, name, ordinal, toString, valueOf

      • Methods inherited from class java.lang.Object

        getClass, notify, notifyAll, wait, wait, wait

    • Method Detail

      • values

        public static FileSystem[] values()
        Returns an array containing the constants of this enum type, in the order they are declared. This method may be used to iterate over the constants as follows: 
        for (FileSystem c : FileSystem.values())
    System.out.println(c);
        Returns:
        an array containing the constants of this enum type, in the order they are declared

      • valueOf

        public static FileSystem valueOf​(java.lang.String name)
        Returns the enum constant of this type with the specified name. The string must match exactly an identifier used to declare an enum constant in this type. (Extraneous whitespace characters are not permitted.)
        Parameters:
        name - the name of the enum constant to be returned.
        Returns:
        the enum constant with the specified name
        Throws:
        java.lang.IllegalArgumentException - if this enum type has no constant with the specified name
        java.lang.NullPointerException - if the argument is null

      • getCurrent

        public static FileSystem getCurrent()
        Gets the current file system.
        Returns:
        the current file system

      • getBlockSize

        public int getBlockSize()
        Gets the file allocation block size in bytes.
        Returns:
        the file allocation block size in bytes.
        Since:
        2.12.0

      • getIllegalFileNameChars

        public char[] getIllegalFileNameChars()
        Gets a cloned copy of the illegal characters for this file system.
        Returns:
        the illegal characters for this file system.

      • getIllegalFileNameCodePoints

        public int[] getIllegalFileNameCodePoints()
        Gets a cloned copy of the illegal code points for this file system.
        Returns:
        the illegal code points for this file system.
        Since:
        2.12.0

      • getMaxFileNameLength

        public int getMaxFileNameLength()
        Gets the maximum length for file names (excluding any folder path).

        This limit applies only to the file name itself, excluding any parent directories.

        The value is expressed in Java char units (UTF-16 code units).

        Note: Because many file systems enforce limits in bytes using a specific encoding rather than in UTF-16 code units, a name that fits this limit may still be rejected by the underlying file system.

        Use isLegalFileName(java.lang.CharSequence) to check whether a given name is valid for the current file system and charset.

        However, any file name longer than this limit is guaranteed to be invalid on the current file system.

        Returns:
        the maximum file name length in characters.

      • getMaxPathLength

        public int getMaxPathLength()
        Gets the maximum length for file paths (may include folders).

        This value is inclusive of all path components and separators. For a limit of each path component see getMaxFileNameLength().

        The value is expressed in Java char units (UTF-16 code units) and represents the longest path that can be safely passed to Java File and Path APIs.

        Note: many operating systems and file systems enforce path length limits in bytes using a specific encoding, rather than in UTF-16 code units. As a result, a path that fits within this limit may still be rejected by the underlying platform.

        Conversely, any path longer than this limit is guaranteed to fail with at least some operating system API calls.

        Returns:
        the maximum file path length in characters.

      • getNameSeparator

        public char getNameSeparator()
        Gets the name separator, '\\' on Windows, '/' on Linux.
        Returns:
        '\\' on Windows, '/' on Linux.
        Since:
        2.12.0

      • getReservedFileNames

        public java.lang.String[] getReservedFileNames()
        Gets a cloned copy of the reserved file names.
        Returns:
        the reserved file names.

      • isCasePreserving

        public boolean isCasePreserving()
        Tests whether this file system preserves case.
        Returns:
        Whether this file system preserves case.

      • isCaseSensitive

        public boolean isCaseSensitive()
        Tests whether this file system is case-sensitive.
        Returns:
        Whether this file system is case-sensitive.

      • isLegalFileName

        public boolean isLegalFileName​(java.lang.CharSequence candidate)
        Tests if a candidate file name (without a path) is a legal file name.

        Takes a file name like "filename.ext" or "filename" and checks:

        • if the file name length is legal
        • if the file name is not a reserved file name
        • if the file name does not contain illegal characters
        Parameters:
        candidate - A candidate file name (without a path) like "filename.ext" or "filename".
        Returns:
        true if the candidate name is legal.

      • isLegalFileName

        public boolean isLegalFileName​(java.lang.CharSequence candidate,
                               java.nio.charset.Charset charset)
        Tests if a candidate file name (without a path) is a legal file name.

        Takes a file name like "filename.ext" or "filename" and checks:

        • if the file name length is legal
        • if the file name is not a reserved file name
        • if the file name does not contain illegal characters
        Parameters:
        candidate - A candidate file name (without a path) like "filename.ext" or "filename".
        charset - The charset to use when the file name length is measured in bytes.
        Returns:
        true if the candidate name is legal.
        Since:
        2.21.0

      • isReservedFileName

        public boolean isReservedFileName​(java.lang.CharSequence candidate)
        Tests whether the given string is a reserved file name.
        Parameters:
        candidate - the string to test.
        Returns:
        true if the given string is a reserved file name.

      • normalizeSeparators

        public java.lang.String normalizeSeparators​(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.
        Since:
        2.12.0

      • supportsDriveLetter

        public boolean supportsDriveLetter()
        Tests whether this file system support driver letters.

        Windows supports driver letters as do other operating systems. Whether these other OS's still support Java like OS/2, is a different matter.

        Returns:
        whether this file system support driver letters.
        Since:
        2.9.0
        See Also:
        Operating systems that use drive letter assignment

      • toLegalFileName

        public java.lang.String toLegalFileName​(java.lang.CharSequence candidate,
                                        char replacement,
                                        java.nio.charset.Charset charset)
        Converts a candidate file name (without a path) to a legal file name.

        Takes a file name like "filename.ext" or "filename" and:

        • replaces illegal characters by the given replacement character
        • truncates the name to getMaxFileNameLength() if necessary
        Parameters:
        candidate - A candidate file name (without a path) like "filename.ext" or "filename".
        replacement - Illegal characters in the candidate name are replaced by this character.
        charset - The charset to use when the file name length is measured in bytes.
        Returns:
        a String without illegal characters.
        Since:
        2.21.0

      • toLegalFileName

        public java.lang.String toLegalFileName​(java.lang.String candidate,
                                        char replacement)
        Converts a candidate file name (without a path) to a legal file name.

        Takes a file name like "filename.ext" or "filename" and:

        • replaces illegal characters by the given replacement character
        • truncates the name to getMaxFileNameLength() if necessary
        Parameters:
        candidate - A candidate file name (without a path) like "filename.ext" or "filename".
        replacement - Illegal characters in the candidate name are replaced by this character.
        Returns:
        a String without illegal characters.