Package info.freelibrary.util

Class FileUtils

java.lang.Object

info.freelibrary.util.FileUtils

public final class FileUtils
extends Object

Utilities for working with files.

Field Summary

Fields

Modifier and Type	Field	Description
static String	DATE_FORMAT	A date format pattern.

Method Summary

Modifier and Type	Method	Description
static int	convertToInt(Set<PosixFilePermission> aPermSet)	Convert a PosixFilePermission set to an integer permissions mode.
static Set<PosixFilePermission>	convertToPermissionsSet(int aMode)	Converts an file permissions mode integer to a PosixFilePermission set.
static void	copy(File aFromFile, File aToFile)	Copies a file or directory from one place to another.
static boolean	delete(File aDir)	Deletes a directory and all its children.
static boolean	dirIsUseable(String aDirName, String aPermString)	Tests that the supplied directory exists and can be used according to the supplied permissions string (e.g., 'rwx').
static String	getExt(String aFileName)	Returns a file extension (as delimited by a period).
static String	getMimeType(String aFileUrl)	Gets the MIME type of the supplied file URL.
static long	getSize(File aFile)	Gets the calculated size of a directory of files.
static String	hash(File aFile, String aAlgorithm)	Get a hash for a supplied file.
static File[]	listFiles(File aDir, FilenameFilter aFilter)	An array of all the files in the supplied directory that match the supplied FilenameFilter.
static File[]	listFiles(File aDir, FilenameFilter aFilter, boolean aDeepListing)	An array of all the files in the supplied directory that match the supplied FilenameFilter.
static File[]	listFiles(File aDir, FilenameFilter aFilter, boolean aDeepListing, String... aIgnoreList)	An array of all the files in the supplied directory that match the supplied FilenameFilter.
static String	sizeFromBytes(long aByteCount)	Returns a human readable size from a large number of bytes.
static String	sizeFromBytes(long aByteCount, boolean aAbbreviatedLabel)	Returns a human readable size from a large number of bytes.
static String	stripExt(File aFile)	Return a file name without the dot extension.
static String	stripExt(String aFileName)	Return a file name without the dot extension.
static File	toFile(URL aURL)	Returns a Java File for the supplied file-based URL.
static Map<String,List<String>>	toHashMap(String aFilePath)	Returns a Map representation of the supplied directory's structure.
static Map<String,List<String>>	toHashMap(String aFilePath, String aPattern)	Returns a Map representation of the supplied directory's structure.
static Map<String,List<String>>	toHashMap(String aFilePath, String aPattern, String... aIgnoreList)	Returns a Map representation of the supplied directory's structure.

Methods inherited from class java.lang.Object

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

Field Detail

DATE_FORMAT

public static final String DATE_FORMAT

A date format pattern.

See Also:

Constant Field Values

Method Detail

toHashMap

public static Map<String,List<String>> toHashMap(String aFilePath)
                                                throws FileNotFoundException

Returns a Map representation of the supplied directory's structure. The map contains the file name as the key and its path as the value. If a file with a name occurs more than once, multiple path values are returned for that file name key. The map that is returned is unmodifiable.

Parameters:

aFilePath - The directory of which you'd like a file listing

Returns:

An unmodifiable map representing the files in the file structure

Throws:

FileNotFoundException - If the directory for the supplied file path does not exist

toHashMap

public static Map<String,List<String>> toHashMap(String aFilePath,
                                                       String aPattern)
                                                throws FileNotFoundException

Returns a Map representation of the supplied directory's structure. The map contains the file name as the key and its path as the value. If a file with a name occurs more than once, multiple path values are returned for that file name key. The map that is returned is unmodifiable.

Parameters:

aFilePath - The directory of which you'd like a file listing

aPattern - A regular expression pattern which the files must match to be returned

Returns:

An unmodifiable map representing the files in the file structure

Throws:

FileNotFoundException - If the directory for the supplied file path does not exist

toHashMap

public static Map<String,List<String>> toHashMap(String aFilePath,
                                                       String aPattern,
                                                       String... aIgnoreList)
                                                throws FileNotFoundException

Returns a Map representation of the supplied directory's structure. The map contains the file name as the key and its path as the value. If a file with a name occurs more than once, multiple path values are returned for that file name key. The map that is returned is unmodifiable.

Parameters:

aFilePath - The directory of which you'd like a file listing

aPattern - A regular expression pattern which the files must match to be returned

aIgnoreList - A list of directories into which we shouldn't descend

Returns:

An unmodifiable map representing the files in the file structure

Throws:

FileNotFoundException - If the directory for the supplied file path does not exist

RuntimeException - If a duplicate file path name is discovered

toFile

public static File toFile(URL aURL)
                   throws MalformedURLException

Returns a Java File for the supplied file-based URL.

Parameters:

aURL - A URL that has a file protocol

Returns:

A Java File for the supplied URL

Throws:

MalformedURLException - If the supplied URL doesn't have a file protocol

listFiles

public static File[] listFiles(File aDir,
                               FilenameFilter aFilter)
                        throws FileNotFoundException

An array of all the files in the supplied directory that match the supplied FilenameFilter.

Parameters:

aDir - A directory from which a file listing should be returned

aFilter - A file name filter which returned files should match

Returns:

An array of matching files

Throws:

FileNotFoundException - If the supplied directory doesn't exist

listFiles

public static File[] listFiles(File aDir,
                               FilenameFilter aFilter,
                               boolean aDeepListing)
                        throws FileNotFoundException

An array of all the files in the supplied directory that match the supplied FilenameFilter.

Parameters:

aDir - A directory from which a file listing should be returned

aFilter - A file name filter which returned files should match

aDeepListing - Whether we should descend through subdirectories

Returns:

An array of matching files

Throws:

FileNotFoundException - If the supplied directory doesn't exist

listFiles

public static File[] listFiles(File aDir,
                               FilenameFilter aFilter,
                               boolean aDeepListing,
                               String... aIgnoreList)
                        throws FileNotFoundException

An array of all the files in the supplied directory that match the supplied FilenameFilter. Directories that match the supplied ignore list will not be included in the result.

Parameters:

aDir - A directory from which a file listing should be returned

aFilter - A file name filter which returned files should match

aDeepListing - Whether we should descend through subdirectories

aIgnoreList - Directory names that should be ignored in the list.

Returns:

An array of matching files

Throws:

FileNotFoundException - If the supplied directory doesn't exist

stripExt

public static String stripExt(File aFile)

Return a file name without the dot extension.

Parameters:

aFile - The file name

Returns:

The file name without the extension

stripExt

public static String stripExt(String aFileName)

Return a file name without the dot extension.

Parameters:

aFileName - The file name from which we want to strip the extension

Returns:

The file name without the extension

getExt

public static String getExt(String aFileName)

Returns a file extension (as delimited by a period).

Parameters:

aFileName - A file name from which to get the extension

Returns:

The extension or an empty string if the file doesn't have an extension

getSize

public static long getSize(File aFile)

Gets the calculated size of a directory of files.

Parameters:

aFile - A file or directory from which to calculate size

Returns:

The calculated size of the supplied directory or file

delete

public static boolean delete(File aDir)

Deletes a directory and all its children.

Parameters:

aDir - A directory to delete

Returns:

True if file was successfully deleted; else, false

copy

public static void copy(File aFromFile,
                        File aToFile)
                 throws IOException

Copies a file or directory from one place to another. This copies a file to a file or a directory to a directory. It does not copy a file to a directory.

Parameters:

aFromFile - A file or directory source

aToFile - A file or directory destination

Throws:

IOException - If there is an exception copying the files or directories

sizeFromBytes

public static String sizeFromBytes(long aByteCount)

Returns a human readable size from a large number of bytes.

Parameters:

aByteCount - A large number of bytes

Returns:

A human readable size

sizeFromBytes

public static String sizeFromBytes(long aByteCount,
                                   boolean aAbbreviatedLabel)

Returns a human readable size from a large number of bytes. You can specify that the human readable size use an abbreviated label (e.g., GB or MB).

Parameters:

aByteCount - A large number of bytes

aAbbreviatedLabel - Whether the label should be abbreviated

Returns:

A human readable size

hash

public static String hash(File aFile,
                          String aAlgorithm)
                   throws NoSuchAlgorithmException,
                          IOException

Get a hash for a supplied file.

Parameters:

aFile - A file to get a hash for

aAlgorithm - A hash algorithm supported by MessageDigest

Returns:

A hash string

Throws:

NoSuchAlgorithmException - If the supplied algorithm isn't supported

IOException - If there is trouble reading the file

getMimeType

public static String getMimeType(String aFileUrl)

Gets the MIME type of the supplied file URL. It gets MIME type from URLConnection's file name map.

Parameters:

aFileUrl - A file-based URL

Returns:

The MIME-type name for the supplied file

dirIsUseable

public static boolean dirIsUseable(String aDirName,
                                   String aPermString)

Tests that the supplied directory exists and can be used according to the supplied permissions string (e.g., 'rwx').

Parameters:

aDirName - A name of a directory on the file system

aPermString - A string representing the desired permissions of the directory

Returns:

True if the directory is okay to be used; else, false

convertToPermissionsSet

public static Set<PosixFilePermission> convertToPermissionsSet(int aMode)

Converts an file permissions mode integer to a PosixFilePermission set.

Parameters:

aMode - An integer permissions mode.

Returns:

A PosixFilePermission set

convertToInt

public static int convertToInt(Set<PosixFilePermission> aPermSet)

Convert a PosixFilePermission set to an integer permissions mode.

Parameters:

aPermSet - A PosixFilePermission set

Returns:

A permissions mode integer