jodd.io

Class FileNameUtil

java.lang.Object

jodd.io.FileNameUtil

public class FileNameUtil
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.

Constructor Summary

Constructors

Constructor and Description
FileNameUtil()

Method Summary

Methods

Modifier and Type	Method and 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	concat(java.lang.String basePath, java.lang.String fullFilenameToAdd, boolean unixSeparator)
static java.lang.String	doConcat(java.lang.String basePath, java.lang.String fullFilenameToAdd, char separator)
static boolean	equals(java.lang.String filename1, java.lang.String filename2) Checks whether two filenames are equal exactly.
static boolean	equalsOnSystem(java.lang.String filename1, java.lang.String filename2) Checks whether two filenames are equal using the case rules of the system.
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 boolean	hasExtension(java.lang.String filename) Returns true if file has extension.
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 java.lang.String	normalize(java.lang.String filename)
static java.lang.String	normalize(java.lang.String filename, boolean unixSeparator) Normalizes a path, removing double and single dot path steps.
static java.lang.String	normalizeNoEndSeparator(java.lang.String filename)
static java.lang.String	normalizeNoEndSeparator(java.lang.String filename, boolean unixSeparator) 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	resolveHome(java.lang.String path) Resolve ~ in the path.
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.
static java.lang.String[]	split(java.lang.String filename) Splits filename into a array of four Strings containing prefix, path, basename and extension.

Methods inherited from class java.lang.Object

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

Constructor Detail

FileNameUtil

public FileNameUtil()

Method Detail

normalize

public static java.lang.String normalize(java.lang.String filename)

normalize

public static java.lang.String normalize(java.lang.String filename,
                         boolean unixSeparator)

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)

normalizeNoEndSeparator

public static java.lang.String normalizeNoEndSeparator(java.lang.String filename,
                                       boolean unixSeparator)

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

concat

public static java.lang.String concat(java.lang.String basePath,
                      java.lang.String fullFilenameToAdd,
                      boolean unixSeparator)

doConcat

public static java.lang.String doConcat(java.lang.String basePath,
                        java.lang.String fullFilenameToAdd,
                        char separator)

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

hasExtension

public static boolean hasExtension(java.lang.String filename)

Returns true if file has extension.

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

equals

public static boolean equals(java.lang.String filename1,
             java.lang.String filename2)

Checks whether two filenames are equal exactly.

equalsOnSystem

public static boolean equalsOnSystem(java.lang.String filename1,
                     java.lang.String filename2)

Checks whether two filenames are equal using the case rules of the system.

split

public static java.lang.String[] split(java.lang.String filename)

Splits filename into a array of four Strings containing prefix, path, basename and extension. Path will contain ending separator.

resolveHome

public static java.lang.String resolveHome(java.lang.String path)

Resolve ~ in the path.