Package com.google.common.io

Class MoreFiles

java.lang.Object

com.google.common.io.MoreFiles

@Beta
@GwtIncompatible
public final class MoreFiles
extends Object

Static utilities for use with Path instances, intended to complement Files.

Many methods provided by Guava's Files class for File instances are now available via the JDK's Files class for Path - check the JDK's class if a sibling method from Files appears to be missing from this class.

Since:

21.0

Author:

Colin Decker

Method Summary

Modifier and Type	Method	Description
static ByteSink	asByteSink(Path path, OpenOption... options)	Returns a view of the given path as a ByteSink.
static ByteSource	asByteSource(Path path, OpenOption... options)	Returns a view of the given path as a ByteSource.
static CharSink	asCharSink(Path path, Charset charset, OpenOption... options)	Returns a view of the given path as a CharSink using the given charset.
static CharSource	asCharSource(Path path, Charset charset, OpenOption... options)	Returns a view of the given path as a CharSource using the given charset.
static void	createParentDirectories(Path path, FileAttribute<?>... attrs)	Creates any necessary but nonexistent parent directories of the specified path.
static void	deleteDirectoryContents(Path path, RecursiveDeleteOption... options)	Deletes all files within the directory at the given path recursively.
static void	deleteRecursively(Path path, RecursiveDeleteOption... options)	Deletes the file or directory at the given path recursively.
static boolean	equal(Path path1, Path path2)	Returns true if the files located by the given paths exist, are not directories, and contain the same bytes.
static Traverser<Path>	fileTraverser()	Returns a Traverser instance for the file and directory tree.
static String	getFileExtension(Path path)	Returns the file extension for the file at the given path, or the empty string if the file has no extension.
static String	getNameWithoutExtension(Path path)	Returns the file name without its file extension or path.
static Predicate<Path>	isDirectory(LinkOption... options)	Returns a predicate that returns the result of Files.isDirectory(Path, LinkOption...) on input paths with the given link options.
static Predicate<Path>	isRegularFile(LinkOption... options)	Returns a predicate that returns the result of Files.isRegularFile(Path, LinkOption...) on input paths with the given link options.
static ImmutableList<Path>	listFiles(Path dir)	Returns an immutable list of paths to the files contained in the given directory.
static void	touch(Path path)	Like the unix command of the same name, creates an empty file or updates the last modified timestamp of the existing file at the given path to the current system time.

Methods inherited from class java.lang.Object

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

Method Detail

asByteSource

public static ByteSource asByteSource(Path path,
                                      OpenOption... options)

Returns a view of the given path as a ByteSource.

Any open options provided are used when opening streams to the file and may affect the behavior of the returned source and the streams it provides. See StandardOpenOption for the standard options that may be provided. Providing no options is equivalent to providing the READ option.

asByteSink

public static ByteSink asByteSink(Path path,
                                  OpenOption... options)

Returns a view of the given path as a ByteSink.

Any open options provided are used when opening streams to the file and may affect the behavior of the returned sink and the streams it provides. See StandardOpenOption for the standard options that may be provided. Providing no options is equivalent to providing the CREATE, TRUNCATE_EXISTING and WRITE options.

asCharSource

public static CharSource asCharSource(Path path,
                                      Charset charset,
                                      OpenOption... options)

Returns a view of the given path as a CharSource using the given charset.

Any open options provided are used when opening streams to the file and may affect the behavior of the returned source and the streams it provides. See StandardOpenOption for the standard options that may be provided. Providing no options is equivalent to providing the READ option.

asCharSink

public static CharSink asCharSink(Path path,
                                  Charset charset,
                                  OpenOption... options)

Returns a view of the given path as a CharSink using the given charset.

Any open options provided are used when opening streams to the file and may affect the behavior of the returned sink and the streams it provides. See StandardOpenOption for the standard options that may be provided. Providing no options is equivalent to providing the CREATE, TRUNCATE_EXISTING and WRITE options.

listFiles

public static ImmutableList<Path> listFiles(Path dir)
                                     throws IOException

Returns an immutable list of paths to the files contained in the given directory.

Throws:

NoSuchFileException - if the file does not exist (optional specific exception)

NotDirectoryException - if the file could not be opened because it is not a directory (optional specific exception)

IOException - if an I/O error occurs

fileTraverser

public static Traverser<Path> fileTraverser()

Returns a Traverser instance for the file and directory tree. The returned traverser starts from a Path and will return all files and directories it encounters.

The returned traverser attempts to avoid following symbolic links to directories. However, the traverser cannot guarantee that it will not follow symbolic links to directories as it is possible for a directory to be replaced with a symbolic link between checking if the file is a directory and actually reading the contents of that directory.

If the Path passed to one of the traversal methods does not exist or is not a directory, no exception will be thrown and the returned Iterable will contain a single element: that path.

DirectoryIteratorException may be thrown when iterating Iterable instances created by this traverser if an IOException is thrown by a call to listFiles(Path).

Example: MoreFiles.fileTraverser().depthFirstPreOrder(Paths.get("/")) may return the following paths: ["/", "/etc", "/etc/config.txt", "/etc/fonts", "/home", "/home/alice", ...]

Since:

23.5

isDirectory

public static Predicate<Path> isDirectory(LinkOption... options)

Returns a predicate that returns the result of Files.isDirectory(Path, LinkOption...) on input paths with the given link options.

isRegularFile

public static Predicate<Path> isRegularFile(LinkOption... options)

Returns a predicate that returns the result of Files.isRegularFile(Path, LinkOption...) on input paths with the given link options.

equal

public static boolean equal(Path path1,
                            Path path2)
                     throws IOException

Returns true if the files located by the given paths exist, are not directories, and contain the same bytes.

Throws:

IOException - if an I/O error occurs

Since:

22.0

touch

public static void touch(Path path)
                  throws IOException

Like the unix command of the same name, creates an empty file or updates the last modified timestamp of the existing file at the given path to the current system time.

Throws:

IOException

createParentDirectories

public static void createParentDirectories(Path path,
                                           FileAttribute<?>... attrs)
                                    throws IOException

Creates any necessary but nonexistent parent directories of the specified path. Note that if this operation fails, it may have succeeded in creating some (but not all) of the necessary parent directories. The parent directory is created with the given attrs.

Throws:

IOException - if an I/O error occurs, or if any necessary but nonexistent parent directories of the specified file could not be created.

getFileExtension

public static String getFileExtension(Path path)

Returns the file extension for the file at the given path, or the empty string if the file has no extension. The result does not include the '.'.

Note: This method simply returns everything after the last '.' in the file's name as determined by Path.getFileName(). It does not account for any filesystem-specific behavior that the Path API does not already account for. For example, on NTFS it will report "txt" as the extension for the filename "foo.exe:.txt" even though NTFS will drop the ":.txt" part of the name when the file is actually created on the filesystem due to NTFS's Alternate Data Streams.

getNameWithoutExtension

public static String getNameWithoutExtension(Path path)

Returns the file name without its file extension or path. This is similar to the basename unix command. The result does not include the '.'.

deleteRecursively

public static void deleteRecursively(Path path,
                                     RecursiveDeleteOption... options)
                              throws IOException

Deletes the file or directory at the given path recursively. Deletes symbolic links, not their targets (subject to the caveat below).

If an I/O exception occurs attempting to read, open or delete any file under the given directory, this method skips that file and continues. All such exceptions are collected and, after attempting to delete all files, an IOException is thrown containing those exceptions as suppressed exceptions.

Warning: Security of recursive deletes

On a file system that supports symbolic links and does not support SecureDirectoryStream, it is possible for a recursive delete to delete files and directories that are outside the directory being deleted. This can happen if, after checking that a file is a directory (and not a symbolic link), that directory is replaced by a symbolic link to an outside directory before the call that opens the directory to read its entries.

By default, this method throws InsecureRecursiveDeleteException if it can't guarantee the security of recursive deletes. If you wish to allow the recursive deletes anyway, pass RecursiveDeleteOption.ALLOW_INSECURE to this method to override that behavior.

Throws:

NoSuchFileException - if path does not exist (optional specific exception)

InsecureRecursiveDeleteException - if the security of recursive deletes can't be guaranteed for the file system and RecursiveDeleteOption.ALLOW_INSECURE was not specified

IOException - if path or any file in the subtree rooted at it can't be deleted for any reason

deleteDirectoryContents

public static void deleteDirectoryContents(Path path,
                                           RecursiveDeleteOption... options)
                                    throws IOException

Deletes all files within the directory at the given path recursively. Does not delete the directory itself. Deletes symbolic links, not their targets (subject to the caveat below). If path itself is a symbolic link to a directory, that link is followed and the contents of the directory it targets are deleted.

If an I/O exception occurs attempting to read, open or delete any file under the given directory, this method skips that file and continues. All such exceptions are collected and, after attempting to delete all files, an IOException is thrown containing those exceptions as suppressed exceptions.

Warning: Security of recursive deletes

On a file system that supports symbolic links and does not support SecureDirectoryStream, it is possible for a recursive delete to delete files and directories that are outside the directory being deleted. This can happen if, after checking that a file is a directory (and not a symbolic link), that directory is replaced by a symbolic link to an outside directory before the call that opens the directory to read its entries.

By default, this method throws InsecureRecursiveDeleteException if it can't guarantee the security of recursive deletes. If you wish to allow the recursive deletes anyway, pass RecursiveDeleteOption.ALLOW_INSECURE to this method to override that behavior.

Throws:

NoSuchFileException - if path does not exist (optional specific exception)

NotDirectoryException - if the file at path is not a directory (optional specific exception)

InsecureRecursiveDeleteException - if the security of recursive deletes can't be guaranteed for the file system and RecursiveDeleteOption.ALLOW_INSECURE was not specified

IOException - if one or more files can't be deleted for any reason