/* * Copyright 2007-2009 Sun Microsystems, Inc. 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. Sun designates this * particular file as subject to the "Classpath" exception as provided * by Sun 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, * CA 95054 USA or visit www.sun.com if you need additional information or * have any questions. */ package java.nio.file; import java.nio.file.attribute.*; import java.util.Map; import java.io.InputStream; import java.io.OutputStream; import java.io.IOException; /** * A reference to a file. * *

A {@code FileRef} is an object that locates a file and defines methods to * open the file for reading or writing. It also provides access to associated * metadata or file attributes. * * @since 1.7 * @see java.nio.file.attribute.Attributes * @see java.io.File#toPath */ public interface FileRef { /** * Opens the file referenced by this object, returning an input stream to * read from the file. The stream will not be buffered, and is not required * to support the {@link InputStream#mark mark} or {@link InputStream#reset * reset} methods. The stream will be safe for access by multiple concurrent * threads. Reading commences at the beginning of the file. * *

The {@code options} parameter determines how the file is opened. * If no options are present then it is equivalent to opening the file with * the {@link StandardOpenOption#READ READ} option. In addition to the {@code * READ} option, an implementation may also support additional implementation * specific options. * * @return an input stream to read bytes from the file * * @throws IllegalArgumentException * if an invalid combination of options is specified * @throws UnsupportedOperationException * if an unsupported option is specified * @throws IOException * if an I/O error occurs * @throws SecurityException * In the case of the default provider, and a security manager is * installed, the {@link SecurityManager#checkRead(String) checkRead} * method is invoked to check read access to the file. */ InputStream newInputStream(OpenOption... options) throws IOException; /** * Opens or creates the file located by this object for writing, returning * an output stream to write bytes to the file. * *

The {@code options} parameter determines how the file is opened. * If no options are present then this method creates a new file for writing * or truncates an existing file. In addition to the {@link StandardOpenOption * standard} options, an implementation may also support additional * implementation specific options. * *

The resulting stream will not be buffered. The stream will be safe * for access by multiple concurrent threads. * * @param options * options specifying how the file is opened * * @return a new output stream * * @throws IllegalArgumentException * if {@code options} contains an invalid combination of options * @throws UnsupportedOperationException * if an unsupported option is specified * @throws IOException * if an I/O error occurs * @throws SecurityException * In the case of the default provider, and a security manager is * installed, the {@link SecurityManager#checkWrite(String) checkWrite} * method is invoked to check write access to the file. */ OutputStream newOutputStream(OpenOption... options) throws IOException; /** * Returns a file attribute view of a given type. * *

A file attribute view provides a read-only or updatable view of a * set of file attributes. This method is intended to be used where the file * attribute view defines type-safe methods to read or update the file * attributes. The {@code type} parameter is the type of the attribute view * required and the method returns an instance of that type if supported. * The {@link BasicFileAttributeView} type supports access to the basic * attributes of a file. Invoking this method to select a file attribute * view of that type will always return an instance of that class. * *

The {@code options} array may be used to indicate how symbolic links * are handled by the resulting file attribute view for the case that the * file is a symbolic link. By default, symbolic links are followed. If the * option {@link LinkOption#NOFOLLOW_LINKS NOFOLLOW_LINKS} is present then * symbolic links are not followed. This option is ignored by implementations * that do not support symbolic links. * * @param type * the {@code Class} object corresponding to the file attribute view * @param options * options indicating how symbolic links are handled * * @return a file attribute view of the specified type, or {@code null} if * the attribute view type is not available * * @throws UnsupportedOperationException * If options contains an unsupported option. This exception is * specified to allow the {@code LinkOption} enum be extended * in future releases. * * @see Attributes#readBasicFileAttributes */ V getFileAttributeView(Class type, LinkOption... options); /** * Sets the value of a file attribute. * *

The {@code attribute} parameter identifies the attribute to be set * and takes the form: *

* [view-name:]attribute-name *
* where square brackets [...] delineate an optional component and the * character {@code ':'} stands for itself. * *

view-name is the {@link FileAttributeView#name name} of a {@link * FileAttributeView} that identifies a set of file attributes. If not * specified then it defaults to {@code "basic"}, the name of the file * attribute view that identifies the basic set of file attributes common to * many file systems. attribute-name is the name of the attribute * within the set. * *

Usage Example: * Suppose we want to set the DOS "hidden" attribute: * 

     *    file.setAttribute("dos:hidden", true);
     *
* * @param attribute * the attribute to set * @param value * the attribute value * @param options * options indicating how symbolic links are handled * * @throws UnsupportedOperationException * if the attribute view is not available or it does not support * updating the attribute * @throws IllegalArgumentException * if the attribute value is of the correct type but has an * inappropriate value * @throws ClassCastException * If the attribute value is not of the expected type or is a * collection containing elements that are not of the expected * type * @throws IOException * If an I/O error occurs * @throws SecurityException * In the case of the default provider, and a security manager is * installed, its {@link SecurityManager#checkWrite(String) checkWrite} * method denies write access to the file. If this method is invoked * to set security sensitive attributes then the security manager * may be invoked to check for additional permissions. */ void setAttribute(String attribute, Object value, LinkOption... options) throws IOException; /** * Reads the value of a file attribute. * *

The {@code attribute} parameter identifies the attribute to be read * and takes the form: *

* [view-name:]attribute-name *
* where square brackets [...] delineate an optional component and the * character {@code ':'} stands for itself. * *

view-name is the {@link FileAttributeView#name name} of a {@link * FileAttributeView} that identifies a set of file attributes. If not * specified then it defaults to {@code "basic"}, the name of the file * attribute view that identifies the basic set of file attributes common to * many file systems. attribute-name is the name of the attribute. * *

The {@code options} array may be used to indicate how symbolic links * are handled for the case that the file is a symbolic link. By default, * symbolic links are followed and the file attribute of the final target * of the link is read. If the option {@link LinkOption#NOFOLLOW_LINKS * NOFOLLOW_LINKS} is present then symbolic links are not followed and so * the method returns the file attribute of the symbolic link. * *

Usage Example: * Suppose we require the user ID of the file owner on a system that * supports a "{@code unix}" view: * 

     *    int uid = (Integer)file.getAttribute("unix:uid");
     *
* * @param attribute * the attribute to read * @param options * options indicating how symbolic links are handled * @return the attribute value or {@code null} if the attribute view * is not available or it does not support reading the attribute * * reading the attribute * @throws IOException * if an I/O error occurs * @throws SecurityException * In the case of the default provider, and a security manager is * installed, its {@link SecurityManager#checkRead(String) checkRead} * method denies read access to the file. If this method is invoked * to read security sensitive attributes then the security manager * may be invoked to check for additional permissions. */ Object getAttribute(String attribute, LinkOption... options) throws IOException; /** * Reads a set of file attributes as a bulk operation. * *

The {@code attributes} parameter identifies the attributes to be read * and takes the form: *

* [view-name:]attribute-list *
* where square brackets [...] delineate an optional component and the * character {@code ':'} stands for itself. * *

view-name is the {@link FileAttributeView#name name} of a {@link * FileAttributeView} that identifies a set of file attributes. If not * specified then it defaults to {@code "basic"}, the name of the file * attribute view that identifies the basic set of file attributes common to * many file systems. * *

The attribute-list component is a comma separated list of * zero or more names of attributes to read. If the list contains the value * {@code "*"} then all attributes are read. Attributes that are not supported * are ignored and will not be present in the returned map. It is * implementation specific if all attributes are read as an atomic operation * with respect to other file system operations. * *

The following examples demonstrate possible values for the {@code * attributes} parameter: * *

* * * * * * * * * * * * * * * * * *
{@code "*"} Read all {@link BasicFileAttributes basic-file-attributes}.
{@code "size,lastModifiedTime,lastAccessTime"} Reads the file size, last modified time, and last access time * attributes.
{@code "posix:*"} Read all {@link PosixFileAttributes POSIX-file-attributes}..
{@code "posix:permissions,owner,size"} Reads the POSX file permissions, owner, and file size.
*
* *

The {@code options} array may be used to indicate how symbolic links * are handled for the case that the file is a symbolic link. By default, * symbolic links are followed and the file attribute of the final target * of the link is read. If the option {@link LinkOption#NOFOLLOW_LINKS * NOFOLLOW_LINKS} is present then symbolic links are not followed and so * the method returns the file attribute of the symbolic link. * * @param attributes * The attributes to read * @param options * Options indicating how symbolic links are handled * * @return A map of the attributes returned; may be empty. The map's keys * are the attribute names, its values are the attribute values * * @throws IOException * If an I/O error occurs * @throws SecurityException * In the case of the default provider, and a security manager is * installed, its {@link SecurityManager#checkRead(String) checkRead} * method denies read access to the file. If this method is invoked * to read security sensitive attributes then the security manager * may be invoke to check for additional permissions. */ Map readAttributes(String attributes, LinkOption... options) throws IOException; }