/* * Copyright (c) 2007, 2013, Oracle and/or its affiliates. All rights reserved. * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. * * This code is free software; you can redistribute it and/or modify it * under the terms of the GNU General Public License version 2 only, as * published by the Free Software Foundation. Oracle designates this * particular file as subject to the "Classpath" exception as provided * by Oracle in the LICENSE file that accompanied this code. * * This code is distributed in the hope that it will be useful, but WITHOUT * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License * version 2 for more details (a copy is included in the LICENSE file that * accompanied this code). * * You should have received a copy of the GNU General Public License version * 2 along with this work; if not, write to the Free Software Foundation, * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. * * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA * or visit www.oracle.com if you need additional information or have any * questions. */ package java.nio.file; import java.nio.file.attribute.*; import java.nio.file.spi.FileSystemProvider; import java.util.Set; import java.io.Closeable; import java.io.IOException; /** * Provides an interface to a file system and is the factory for objects to * access files and other objects in the file system. * *
The default file system, obtained by invoking the {@link FileSystems#getDefault * FileSystems.getDefault} method, provides access to the file system that is * accessible to the Java virtual machine. The {@link FileSystems} class defines * methods to create file systems that provide access to other types of (custom) * file systems. * *
A file system is the factory for several types of objects: * *
The {@link #getPath getPath} method converts a system dependent * path string, returning a {@link Path} object that may be used * to locate and access a file.
The {@link #getPathMatcher getPathMatcher} method is used * to create a {@link PathMatcher} that performs match operations on * paths.
The {@link #getFileStores getFileStores} method returns an iterator * over the underlying {@link FileStore file-stores}.
The {@link #getUserPrincipalLookupService getUserPrincipalLookupService} * method returns the {@link UserPrincipalLookupService} to lookup users or * groups by name.
The {@link #newWatchService newWatchService} method creates a * {@link WatchService} that may be used to watch objects for changes and * events.
File systems vary greatly. In some cases the file system is a single * hierarchy of files with one top-level root directory. In other cases it may * have several distinct file hierarchies, each with its own top-level root * directory. The {@link #getRootDirectories getRootDirectories} method may be * used to iterate over the root directories in the file system. A file system * is typically composed of one or more underlying {@link FileStore file-stores} * that provide the storage for the files. Theses file stores can also vary in * the features they support, and the file attributes or meta-data that * they associate with files. * *
A file system is open upon creation and can be closed by invoking its * {@link #close() close} method. Once closed, any further attempt to access * objects in the file system cause {@link ClosedFileSystemException} to be * thrown. File systems created by the default {@link FileSystemProvider provider} * cannot be closed. * *
A {@code FileSystem} can provide read-only or read-write access to the * file system. Whether or not a file system provides read-only access is * established when the {@code FileSystem} is created and can be tested by invoking * its {@link #isReadOnly() isReadOnly} method. Attempts to write to file stores * by means of an object associated with a read-only file system throws {@link * ReadOnlyFileSystemException}. * *
File systems are safe for use by multiple concurrent threads. The {@link * #close close} method may be invoked at any time to close a file system but * whether a file system is asynchronously closeable is provider specific * and therefore unspecified. In other words, if a thread is accessing an * object in a file system, and another thread invokes the {@code close} method * then it may require to block until the first operation is complete. Closing * a file system causes all open channels, watch services, and other {@link * Closeable closeable} objects associated with the file system to be closed. * * @since 1.7 */ public abstract class FileSystem implements Closeable { /** * Initializes a new instance of this class. */ protected FileSystem() { } /** * Returns the provider that created this file system. * * @return The provider that created this file system. */ public abstract FileSystemProvider provider(); /** * Closes this file system. * *
After a file system is closed then all subsequent access to the file * system, either by methods defined by this class or on objects associated * with this file system, throw {@link ClosedFileSystemException}. If the * file system is already closed then invoking this method has no effect. * *
Closing a file system will close all open {@link * java.nio.channels.Channel channels}, {@link DirectoryStream directory-streams}, * {@link WatchService watch-service}, and other closeable objects associated * with this file system. The {@link FileSystems#getDefault default} file * system cannot be closed. * * @throws IOException * If an I/O error occurs * @throws UnsupportedOperationException * Thrown in the case of the default file system */ @Override public abstract void close() throws IOException; /** * Tells whether or not this file system is open. * *
File systems created by the default provider are always open. * * @return {@code true} if, and only if, this file system is open */ public abstract boolean isOpen(); /** * Tells whether or not this file system allows only read-only access to * its file stores. * * @return {@code true} if, and only if, this file system provides * read-only access */ public abstract boolean isReadOnly(); /** * Returns the name separator, represented as a string. * *
The name separator is used to separate names in a path string. An * implementation may support multiple name separators in which case this * method returns an implementation specific default name separator. * This separator is used when creating path strings by invoking the {@link * Path#toString() toString()} method. * *
In the case of the default provider, this method returns the same * separator as {@link java.io.File#separator}. * * @return The name separator */ public abstract String getSeparator(); /** * Returns an object to iterate over the paths of the root directories. * *
A file system provides access to a file store that may be composed * of a number of distinct file hierarchies, each with its own top-level * root directory. Unless denied by the security manager, each element in * the returned iterator corresponds to the root directory of a distinct * file hierarchy. The order of the elements is not defined. The file * hierarchies may change during the lifetime of the Java virtual machine. * For example, in some implementations, the insertion of removable media * may result in the creation of a new file hierarchy with its own * top-level directory. * *
When a security manager is installed, it is invoked to check access
* to the each root directory. If denied, the root directory is not returned
* by the iterator. In the case of the default provider, the {@link
* SecurityManager#checkRead(String)} method is invoked to check read access
* to each root directory. It is system dependent if the permission checks
* are done when the iterator is obtained or during iteration.
*
* @return An object to iterate over the root directories
*/
public abstract Iterable The elements of the returned iterator are the {@link
* FileStore FileStores} for this file system. The order of the elements is
* not defined and the file stores may change during the lifetime of the
* Java virtual machine. When an I/O error occurs, perhaps because a file
* store is not accessible, then it is not returned by the iterator.
*
* In the case of the default provider, and a security manager is
* installed, the security manager is invoked to check {@link
* RuntimePermission}("getFileStoreAttributes"). If denied, then
* no file stores are returned by the iterator. In addition, the security
* manager's {@link SecurityManager#checkRead(String)} method is invoked to
* check read access to the file store's top-most directory. If
* denied, the file store is not returned by the iterator. It is system
* dependent if the permission checks are done when the iterator is obtained
* or during iteration.
*
* Usage Example:
* Suppose we want to print the space usage for all file stores:
* The {@link BasicFileAttributeView} is required to be supported and
* therefore the set contains at least one element, "basic".
*
* The {@link FileStore#supportsFileAttributeView(String)
* supportsFileAttributeView(String)} method may be used to test if an
* underlying {@link FileStore} supports the file attributes identified by a
* file attribute view.
*
* @return An unmodifiable set of the names of the supported file attribute
* views
*/
public abstract Set The parsing and conversion to a path object is inherently
* implementation dependent. In the simplest case, the path string is rejected,
* and {@link InvalidPathException} thrown, if the path string contains
* characters that cannot be converted to characters that are legal
* to the file store. For example, on UNIX systems, the NUL (\u0000)
* character is not allowed to be present in a path. An implementation may
* choose to reject path strings that contain names that are longer than those
* allowed by any file store, and where an implementation supports a complex
* path syntax, it may choose to reject path strings that are badly
* formed.
*
* In the case of the default provider, path strings are parsed based
* on the definition of paths at the platform or virtual file system level.
* For example, an operating system may not allow specific characters to be
* present in a file name, but a specific underlying file store may impose
* different or additional restrictions on the set of legal
* characters.
*
* This method throws {@link InvalidPathException} when the path string
* cannot be converted to a path. Where possible, and where applicable,
* the exception is created with an {@link InvalidPathException#getIndex
* index} value indicating the first position in the {@code path} parameter
* that caused the path string to be rejected.
*
* @param first
* the path string or initial part of the path string
* @param more
* additional strings to be joined to form the path string
*
* @return the resulting {@code Path}
*
* @throws InvalidPathException
* If the path string cannot be converted
*/
public abstract Path getPath(String first, String... more);
/**
* Returns a {@code PathMatcher} that performs match operations on the
* {@code String} representation of {@link Path} objects by interpreting a
* given pattern.
*
* The {@code syntaxAndPattern} parameter identifies the syntax and the
* pattern and takes the form:
* A {@code FileSystem} implementation supports the "{@code glob}" and
* "{@code regex}" syntaxes, and may support others. The value of the syntax
* component is compared without regard to case.
*
* When the syntax is "{@code glob}" then the {@code String}
* representation of the path is matched using a limited pattern language
* that resembles regular expressions but with a simpler syntax. For example:
*
* The following rules are used to interpret glob patterns:
*
* The {@code *} character matches zero or more {@link Character
* characters} of a {@link Path#getName(int) name} component without
* crossing directory boundaries. The {@code **} characters matches zero or more {@link Character
* characters} crossing directory boundaries. The {@code ?} character matches exactly one character of a
* name component. The backslash character ({@code \}) is used to escape characters
* that would otherwise be interpreted as special characters. The expression
* {@code \\} matches a single backslash and "\{" matches a left brace
* for example. The {@code [ ]} characters are a bracket expression that
* match a single character of a name component out of a set of characters.
* For example, {@code [abc]} matches {@code "a"}, {@code "b"}, or {@code "c"}.
* The hyphen ({@code -}) may be used to specify a range so {@code [a-z]}
* specifies a range that matches from {@code "a"} to {@code "z"} (inclusive).
* These forms can be mixed so [abce-g] matches {@code "a"}, {@code "b"},
* {@code "c"}, {@code "e"}, {@code "f"} or {@code "g"}. If the character
* after the {@code [} is a {@code !} then it is used for negation so {@code
* [!a-c]} matches any character except {@code "a"}, {@code "b"}, or {@code
* "c"}.
* Within a bracket expression the {@code *}, {@code ?} and {@code \}
* characters match themselves. The ({@code -}) character matches itself if
* it is the first character within the brackets, or the first character
* after the {@code !} if negating. The {@code { }} characters are a group of subpatterns, where
* the group matches if any subpattern in the group matches. The {@code ","}
* character is used to separate the subpatterns. Groups cannot be nested.
* Leading period/dot characters in file name are
* treated as regular characters in match operations. For example,
* the {@code "*"} glob pattern matches file name {@code ".login"}.
* The {@link Files#isHidden} method may be used to test whether a file
* is considered hidden.
* All other characters match themselves in an implementation
* dependent manner. This includes characters representing any {@link
* FileSystem#getSeparator name-separators}. The matching of {@link Path#getRoot root} components is highly
* implementation-dependent and is not specified. When the syntax is "{@code regex}" then the pattern component is a
* regular expression as defined by the {@link java.util.regex.Pattern}
* class.
*
* For both the glob and regex syntaxes, the matching details, such as
* whether the matching is case sensitive, are implementation-dependent
* and therefore not specified.
*
* @param syntaxAndPattern
* The syntax and pattern
*
* @return A path matcher that may be used to match paths against the pattern
*
* @throws IllegalArgumentException
* If the parameter does not take the form: {@code syntax:pattern}
* @throws java.util.regex.PatternSyntaxException
* If the pattern is invalid
* @throws UnsupportedOperationException
* If the pattern syntax is not known to the implementation
*
* @see Files#newDirectoryStream(Path,String)
*/
public abstract PathMatcher getPathMatcher(String syntaxAndPattern);
/**
* Returns the {@code UserPrincipalLookupService} for this file system
* (optional operation). The resulting lookup service may be used to
* lookup user or group names.
*
* Usage Example:
* Suppose we want to make "joe" the owner of a file:
* This method constructs a new watch service that may be used to watch
* registered objects for changes and events.
*
* @return a new watch service
*
* @throws UnsupportedOperationException
* If this {@code FileSystem} does not support watching file system
* objects for changes and events. This exception is not thrown
* by {@code FileSystems} created by the default provider.
* @throws IOException
* If an I/O error occurs
*/
public abstract WatchService newWatchService() throws IOException;
}
* for (FileStore store: FileSystems.getDefault().getFileStores()) {
* long total = store.getTotalSpace() / 1024;
* long used = (store.getTotalSpace() - store.getUnallocatedSpace()) / 1024;
* long avail = store.getUsableSpace() / 1024;
* System.out.format("%-20s %12d %12d %12d%n", store, total, used, avail);
* }
*
*
* @return An object to iterate over the backing file stores
*/
public abstract Iterable
* where {@code ':'} stands for itself.
*
*
* syntax:pattern
*
*
*
*
*
*
*
* {@code *.java}
* Matches a path that represents a file name ending in {@code .java}
*
*
* {@code *.*}
* Matches file names containing a dot
*
*
* {@code *.{java,class}}
* Matches file names ending with {@code .java} or {@code .class}
*
*
* {@code foo.?}
* Matches file names starting with {@code foo.} and a single
* character extension
*
*
* /home/*/*
* Matches /home/gus/data
*
*
*
* /home/**
* Matches /home/gus and
* /home/gus/data
*
*
*
*
* UserPrincipalLookupService lookupService = FileSystems.getDefault().getUserPrincipalLookupService();
* Files.setOwner(path, lookupService.lookupPrincipalByName("joe"));
*
*
* @throws UnsupportedOperationException
* If this {@code FileSystem} does not does have a lookup service
*
* @return The {@code UserPrincipalLookupService} for this file system
*/
public abstract UserPrincipalLookupService getUserPrincipalLookupService();
/**
* Constructs a new {@link WatchService} (optional operation).
*
*