org.apache.flink.util

Class FileUtils

java.lang.Object

org.apache.flink.util.FileUtils

public final class FileUtils
extends Object

This is a utility class to deal files and directories. Contains utilities for recursive deletion and creation of temporary files.

Field Summary

Fields

Modifier and Type	Field and Description
static String	CLASS_FILE_EXTENSION
static String	PACKAGE_SEPARATOR

Method Summary

Modifier and Type	Method and Description
static Path	absolutizePath(Path pathToAbsolutize) Absolutize the given path if it is relative.
static void	cleanDirectory(File directory) Removes all files contained within a directory, without removing the directory itself.
static Path	compressDirectory(Path directory, Path target)
static void	copy(Path sourcePath, Path targetPath, boolean executable) Copies all files from source to target and sets executable flag.
static void	deleteDirectory(File directory) Deletes the given directory recursively.
static void	deleteDirectoryQuietly(File directory) Deletes the given directory recursively, not reporting any I/O exceptions that occur.
static void	deleteFileOrDirectory(File file) Removes the given file or directory recursively.
static Path	expandDirectory(Path file, Path targetDirectory)
static Path	getCurrentWorkingDirectory() Returns the current working directory as specified by the user.dir system property.
static String	getRandomFilename(String prefix) Constructs a random filename with the given prefix and a random part generated from hex characters.
static Path	getTargetPathIfContainsSymbolicPath(Path path) Get a target path(the path that replaced symbolic links with linked path) if the original path contains symbolic path, return the original path otherwise.
static boolean	isJarFile(Path file) Checks whether the given file has a jar extension.
static Path[]	listDirectory(Path directory) Lists the given directory in a resource-leak-safe way.
static Collection<Path>	listFilesInDirectory(Path directory, java.util.function.Predicate<Path> fileFilter) List the directory recursively and return the files that satisfy the fileFilter.
static byte[]	readAllBytes(Path path) Reads all the bytes from a file.
static String	readFile(File file, String charsetName)
static String	readFileUtf8(File file)
static Path	relativizePath(Path basePath, Path pathToRelativize) Relativize the given path with respect to the given base path if it is absolute.
static String	stripFileExtension(String fileName) Remove the extension of the file name.
static URL	toURL(Path path) Converts the given Path into a file URL.
static void	writeCompletely(WritableByteChannel channel, ByteBuffer src)
static void	writeFile(File file, String contents, String encoding)
static void	writeFileUtf8(File file, String contents)

Methods inherited from class java.lang.Object

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

Field Detail

CLASS_FILE_EXTENSION

public static final String CLASS_FILE_EXTENSION

See Also:

Constant Field Values

PACKAGE_SEPARATOR

public static final String PACKAGE_SEPARATOR

See Also:

Constant Field Values

Method Detail

writeCompletely

public static void writeCompletely(WritableByteChannel channel,
                                   ByteBuffer src)
                            throws IOException

Throws:

IOException

listDirectory

public static Path[] listDirectory(Path directory)
                            throws IOException

Lists the given directory in a resource-leak-safe way.

Throws:

IOException

getRandomFilename

public static String getRandomFilename(String prefix)

Constructs a random filename with the given prefix and a random part generated from hex characters.

Parameters:

prefix - the prefix to the filename to be constructed

Returns:

the generated random filename with the given prefix

readFile

public static String readFile(File file,
                              String charsetName)
                       throws IOException

Throws:

IOException

readFileUtf8

public static String readFileUtf8(File file)
                           throws IOException

Throws:

IOException

writeFile

public static void writeFile(File file,
                             String contents,
                             String encoding)
                      throws IOException

Throws:

IOException

writeFileUtf8

public static void writeFileUtf8(File file,
                                 String contents)
                          throws IOException

Throws:

IOException

readAllBytes

public static byte[] readAllBytes(Path path)
                           throws IOException

Reads all the bytes from a file. The method ensures that the file is closed when all bytes have been read or an I/O error, or other runtime exception, is thrown.

This is an implementation that follow Files.readAllBytes(java.nio.file.Path), and the difference is that it limits the size of the direct buffer to avoid direct-buffer OutOfMemoryError. When Files.readAllBytes(java.nio.file.Path) or other interfaces in java API can do this in the future, we should remove it.

Parameters:

path - the path to the file

Returns:

a byte array containing the bytes read from the file

Throws:

IOException - if an I/O error occurs reading from the stream

OutOfMemoryError - if an array of the required size cannot be allocated, for example the file is larger that 2GB

deleteFileOrDirectory

public static void deleteFileOrDirectory(File file)
                                  throws IOException

Removes the given file or directory recursively.

If the file or directory does not exist, this does not throw an exception, but simply does nothing. It considers the fact that a file-to-be-deleted is not present a success.

This method is safe against other concurrent deletion attempts.

Parameters:

file - The file or directory to delete.

Throws:

IOException - Thrown if the directory could not be cleaned for some reason, for example due to missing access/write permissions.

deleteDirectory

public static void deleteDirectory(File directory)
                            throws IOException

Deletes the given directory recursively.

If the directory does not exist, this does not throw an exception, but simply does nothing. It considers the fact that a directory-to-be-deleted is not present a success.

This method is safe against other concurrent deletion attempts.

Parameters:

directory - The directory to be deleted.

Throws:

IOException - Thrown if the given file is not a directory, or if the directory could not be deleted for some reason, for example due to missing access/write permissions.

deleteDirectoryQuietly

public static void deleteDirectoryQuietly(File directory)

Deletes the given directory recursively, not reporting any I/O exceptions that occur.

This method is identical to deleteDirectory(File), except that it swallows all exceptions and may leave the job quietly incomplete.

Parameters:

directory - The directory to delete.

cleanDirectory

public static void cleanDirectory(File directory)
                           throws IOException

Removes all files contained within a directory, without removing the directory itself.

This method is safe against other concurrent deletion attempts.

Parameters:

directory - The directory to remove all files from.

Throws:

FileNotFoundException - Thrown if the directory itself does not exist.

IOException - Thrown if the file indicates a proper file and not a directory, or if the directory could not be cleaned for some reason, for example due to missing access/write permissions.

copy

public static void copy(Path sourcePath,
                        Path targetPath,
                        boolean executable)
                 throws IOException

Copies all files from source to target and sets executable flag. Paths might be on different systems.

Parameters:

sourcePath - source path to copy from

targetPath - target path to copy to

executable - if target file should be executable

Throws:

IOException - if the copy fails

compressDirectory

public static Path compressDirectory(Path directory,
                                     Path target)
                              throws IOException

Throws:

IOException

expandDirectory

public static Path expandDirectory(Path file,
                                   Path targetDirectory)
                            throws IOException

Throws:

IOException

listFilesInDirectory

public static Collection<Path> listFilesInDirectory(Path directory,
                                                    java.util.function.Predicate<Path> fileFilter)
                                             throws IOException

List the directory recursively and return the files that satisfy the fileFilter.

Parameters:

directory - the directory to be listed

fileFilter - a file filter

Returns:

a collection of Files

Throws:

IOException - if an I/O error occurs while listing the files in the given directory

absolutizePath

public static Path absolutizePath(Path pathToAbsolutize)
                           throws IOException

Absolutize the given path if it is relative.

Parameters:

pathToAbsolutize - path which is being absolutized if it is a relative path

Returns:

the absolutized path

Throws:

IOException

relativizePath

public static Path relativizePath(Path basePath,
                                  Path pathToRelativize)

Relativize the given path with respect to the given base path if it is absolute.

Parameters:

basePath - to relativize against

pathToRelativize - path which is being relativized if it is an absolute path

Returns:

the relativized path

getCurrentWorkingDirectory

public static Path getCurrentWorkingDirectory()

Returns the current working directory as specified by the user.dir system property.

Returns:

current working directory

isJarFile

public static boolean isJarFile(Path file)

Checks whether the given file has a jar extension.

Parameters:

file - to check

Returns:

true if the file has a jar extension, otherwise false

stripFileExtension

public static String stripFileExtension(String fileName)

Remove the extension of the file name.

Parameters:

fileName - to strip

Returns:

the file name without extension

getTargetPathIfContainsSymbolicPath

public static Path getTargetPathIfContainsSymbolicPath(Path path)
                                                throws IOException

Get a target path(the path that replaced symbolic links with linked path) if the original path contains symbolic path, return the original path otherwise.

Parameters:

path - the original path.

Returns:

the path that replaced symbolic links with real path.

Throws:

IOException

toURL

public static URL toURL(Path path)
                 throws MalformedURLException

Converts the given Path into a file URL. The resulting url is relative iff the given path is relative.

Parameters:

path - to convert into a URL.

Returns:

URL

Throws:

MalformedURLException - if the path could not be converted into a file URL