/* * 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.attribute; import java.nio.file.*; import java.io.IOException; import java.util.*; import java.util.concurrent.TimeUnit; /** * This class consists exclusively of static methods that operate on or return * the attributes of files or file stores. These methods provide for convenient * use of the {@link AttributeView attribute-views} defined in this package. * * @since 1.7 */ public final class Attributes { private Attributes() { } /** * Splits the given attribute name into the name of an attribute view and * the attribute. If the attribute view is not identified then it assumed * to be "basic". */ private static String[] split(String attribute) { String[] s = new String[2]; int pos = attribute.indexOf(':'); if (pos == -1) { s[0] = "basic"; s[1] = attribute; } else { s[0] = attribute.substring(0, pos++); s[1] = (pos == attribute.length()) ? "" : attribute.substring(pos); } return s; } /** * 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: * 

     *    Attributes.setAttribute(file, "dos:hidden", true);
     *
* * @param file * A file reference that locates the file * @param attribute * The attribute to set * @param value * The attribute value * * @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. */ public static void setAttribute(FileRef file, String attribute, Object value) throws IOException { String[] s = split(attribute); FileAttributeView view = file.getFileAttributeView(s[0]); if (view == null) throw new UnsupportedOperationException("View '" + s[0] + "' not available"); view.setAttribute(s[1], value); } /** * 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)Attributes.getAttribute(file, "unix:uid");
     *
* * @param file * A file reference that locates the file * @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 * * @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. */ public static Object getAttribute(FileRef file, String attribute, LinkOption... options) throws IOException { String[] s = split(attribute); FileAttributeView view = file.getFileAttributeView(s[0], options); if (view != null) return view.getAttribute(s[1]); // view not available return null; } /** * 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 attributes of the final target * of the link are 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 attributes of the symbolic link. * * @param file * A file reference that locates the file * @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. */ public static Map readAttributes(FileRef file, String attributes, LinkOption... options) throws IOException { String[] s = split(attributes); FileAttributeView view = file.getFileAttributeView(s[0], options); if (view != null) { // further split attributes into the first and rest. String[] names = s[1].split(","); int rem = names.length-1; String first = names[0]; String[] rest = new String[rem]; if (rem > 0) System.arraycopy(names, 1, rest, 0, rem); return view.readAttributes(first, rest); } // view not available return Collections.emptyMap(); } /** * Reads the basic file attributes of a file. * *

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 attributes of the final target * of the link are 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 attributes of the symbolic link. This option * should be used where there is a need to determine if a file is a * symbolic link: * 

     *    boolean isSymbolicLink = Attributes.readBasicFileAttributes(file, NOFOLLOW_LINKS).isSymbolicLink();
     *
* *

It is implementation specific if all file attributes are read as an * atomic operation with respect to other file system operations. * * @param file * A file reference that locates the file * @param options * Options indicating how symbolic links are handled * * @return The basic file attributes * * @throws IOException * If an I/O error occurs * @throws SecurityException * In the case of the default provider, the security manager's {@link * SecurityManager#checkRead(String) checkRead} method is invoked * to check read access to file * * @see BasicFileAttributeView#readAttributes */ public static BasicFileAttributes readBasicFileAttributes(FileRef file, LinkOption... options) throws IOException { return file.getFileAttributeView(BasicFileAttributeView.class, options) .readAttributes(); } /** * Reads the POSIX file attributes of a file. * *

The {@code file} parameter locates a file that supports the {@link * PosixFileAttributeView}. This file attribute view provides access to a * subset of the file attributes commonly associated with files on file * systems used by operating systems that implement the Portable Operating * System Interface (POSIX) family of standards. It is implementation * specific if all file attributes are read as an atomic operation with * respect to other file system operations. * *

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 attributes of the final target * of the link are 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 attributes of the symbolic link. * * @param file * A file reference that locates the file * @param options * Options indicating how symbolic links are handled * * @return The POSIX file attributes * * @throws UnsupportedOperationException * If the {@code PosixFileAttributeView} is not available * @throws IOException * If an I/O error occurs * @throws SecurityException * In the case of the default provider, and a security manager is * installed, it denies {@link RuntimePermission}("accessUserInformation") * or its {@link SecurityManager#checkRead(String) checkRead} method * denies read access to the file. * * @see PosixFileAttributeView#readAttributes */ public static PosixFileAttributes readPosixFileAttributes(FileRef file, LinkOption... options) throws IOException { PosixFileAttributeView view = file.getFileAttributeView(PosixFileAttributeView.class, options); if (view == null) throw new UnsupportedOperationException(); return view.readAttributes(); } /** * Reads the DOS file attributes of a file. * *

The {@code file} parameter locates a file that supports the {@link * DosFileAttributeView}. This file attribute view provides access to * legacy "DOS" attributes supported by the file systems such as File * Allocation Table (FAT), commonly used in consumer devices. It is * implementation specific if all file attributes are read as an atomic * operation with respect to other file system operations. * *

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 attributes of the final target * of the link are 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 attributes of the symbolic link. * * @param file * A file reference that locates the file * @param options * Options indicating how symbolic links are handled * * @return The DOS file attributes * * @throws UnsupportedOperationException * If the {@code DosFileAttributeView} is not available * @throws IOException * If an I/O error occurs * @throws SecurityException * In the case of the default provider, the security manager's {@link * SecurityManager#checkRead(String) checkRead} method is invoked * to check read access to file * * @see DosFileAttributeView#readAttributes */ public static DosFileAttributes readDosFileAttributes(FileRef file, LinkOption... options) throws IOException { DosFileAttributeView view = file.getFileAttributeView(DosFileAttributeView.class, options); if (view == null) throw new UnsupportedOperationException(); return view.readAttributes(); } /** * Returns the owner of a file. * *

The {@code file} parameter locates a file that supports the {@link * FileOwnerAttributeView}. This file attribute view provides access to * a file attribute that is the owner of the file. * * @param file * A file reference that locates the file * * @return A user principal representing the owner of the file * * @throws UnsupportedOperationException * If the {@code FileOwnerAttributeView} is not available * @throws IOException * If an I/O error occurs * @throws SecurityException * In the case of the default provider, and a security manager is * installed, it denies {@link RuntimePermission}("accessUserInformation") * or its {@link SecurityManager#checkRead(String) checkRead} method * denies read access to the file. * * @see FileOwnerAttributeView#getOwner */ public static UserPrincipal getOwner(FileRef file) throws IOException { FileOwnerAttributeView view = file.getFileAttributeView(FileOwnerAttributeView.class); if (view == null) throw new UnsupportedOperationException(); return view.getOwner(); } /** * Updates the file owner. * *

The {@code file} parameter locates a file that supports the {@link * FileOwnerAttributeView}. This file attribute view provides access to * a file attribute that is the owner of the file. * * @param file * A file reference that locates the file * @param owner * The new file owner * * @throws UnsupportedOperationException * If the {@code FileOwnerAttributeView} is not available * @throws IOException * If an I/O error occurs * @throws SecurityException * In the case of the default provider, and a security manager is * installed, it denies {@link RuntimePermission}("accessUserInformation") * or its {@link SecurityManager#checkWrite(String) checkWrite} * method denies write access to the file. * * @see FileOwnerAttributeView#setOwner */ public static void setOwner(FileRef file, UserPrincipal owner) throws IOException { FileOwnerAttributeView view = file.getFileAttributeView(FileOwnerAttributeView.class); if (view == null) throw new UnsupportedOperationException(); view.setOwner(owner); } /** * Reads a file's Access Control List (ACL). * *

The {@code file} parameter locates a file that supports the {@link * AclFileAttributeView}. This file attribute view provides access to ACLs * based on the ACL model specified in * RFC 3530. * * @param file * A file reference that locates the file * * @return An ordered list of {@link AclEntry entries} representing the * ACL. The returned list is modifiable. * * @throws UnsupportedOperationException * If the {@code AclAttributeView} is not available * @throws IOException * If an I/O error occurs * @throws SecurityException * In the case of the default provider, and a security manager is * installed, it denies {@link RuntimePermission}("accessUserInformation") * or its {@link SecurityManager#checkRead(String) checkRead} method * denies read access to the file. * * @see AclFileAttributeView#getAcl */ public static List getAcl(FileRef file) throws IOException { AclFileAttributeView view = file.getFileAttributeView(AclFileAttributeView.class); if (view == null) throw new UnsupportedOperationException(); return view.getAcl(); } /** * Updates a file's Access Control List (ACL). * *

The {@code file} parameter locates a file that supports the {@link * AclFileAttributeView}. This file attribute view provides access to ACLs * based on the ACL model specified in * RFC 3530. * * @param file * A file reference that locates the file * @param acl * The new file ACL * * @throws UnsupportedOperationException * If the {@code AclFileAttributeView} is not available * @throws IOException * If an I/O error occurs * @throws SecurityException * In the case of the default provider, and a security manager is * installed, it denies {@link RuntimePermission}("accessUserInformation") * or its {@link SecurityManager#checkWrite(String) checkWrite} * method denies write access to the file. * * @see AclFileAttributeView#setAcl */ public static void setAcl(FileRef file, List acl) throws IOException { AclFileAttributeView view = file.getFileAttributeView(AclFileAttributeView.class); if (view == null) throw new UnsupportedOperationException(); view.setAcl(acl); } /** * Updates the value of a file's last modified time attribute. * *

The time value is measured since the epoch * (00:00:00 GMT, January 1, 1970) and is converted to the precision supported * by the file system. Converting from finer to coarser granularities result * in precision loss. * *

If the file system does not support a last modified time attribute then * this method has no effect. * * @param file * A file reference that locates the file * * @param lastModifiedTime * The new last modified time, or {@code -1L} to update it to * the current time * @param unit * A {@code TimeUnit} determining how to interpret the * {@code lastModifiedTime} parameter * * @throws IllegalArgumentException * If the {@code lastModifiedime} parameter is a negative value other * than {@code -1L} * @throws IOException * If an I/O error occurs * @throws SecurityException * In the case of the default provider, the security manager's {@link * SecurityManager#checkWrite(String) checkWrite} method is invoked * to check write access to file * * @see BasicFileAttributeView#setTimes */ public static void setLastModifiedTime(FileRef file, long lastModifiedTime, TimeUnit unit) throws IOException { file.getFileAttributeView(BasicFileAttributeView.class) .setTimes(lastModifiedTime, null, null, unit); } /** * Updates the value of a file's last access time attribute. * *

The time value is measured since the epoch * (00:00:00 GMT, January 1, 1970) and is converted to the precision supported * by the file system. Converting from finer to coarser granularities result * in precision loss. * *

If the file system does not support a last access time attribute then * this method has no effect. * * @param lastAccessTime * The new last access time, or {@code -1L} to update it to * the current time * @param unit * A {@code TimeUnit} determining how to interpret the * {@code lastModifiedTime} parameter * * @throws IllegalArgumentException * If the {@code lastAccessTime} parameter is a negative value other * than {@code -1L} * @throws IOException * If an I/O error occurs * @throws SecurityException * In the case of the default provider, the security manager's {@link * SecurityManager#checkWrite(String) checkWrite} method is invoked * to check write access to file * * @see BasicFileAttributeView#setTimes */ public static void setLastAccessTime(FileRef file, long lastAccessTime, TimeUnit unit) throws IOException { file.getFileAttributeView(BasicFileAttributeView.class) .setTimes(null, lastAccessTime, null, unit); } /** * Sets a file's POSIX permissions. * *

The {@code file} parameter is a reference to an existing file. It * supports the {@link PosixFileAttributeView} that provides access to file * attributes commonly associated with files on file systems used by * operating systems that implement the Portable Operating System Interface * (POSIX) family of standards. * * @param file * A file reference that locates the file * @param perms * The new set of permissions * * @throws UnsupportedOperationException * If {@code PosixFileAttributeView} is not available * @throws ClassCastException * If the sets contains elements that are not of type {@code * PosixFilePermission} * @throws IOException * If an I/O error occurs * @throws SecurityException * In the case of the default provider, and a security manager is * installed, it denies {@link RuntimePermission}("accessUserInformation") * or its {@link SecurityManager#checkWrite(String) checkWrite} * method denies write access to the file. * * @see PosixFileAttributeView#setPermissions */ public static void setPosixFilePermissions(FileRef file, Set perms) throws IOException { PosixFileAttributeView view = file.getFileAttributeView(PosixFileAttributeView.class); if (view == null) throw new UnsupportedOperationException(); view.setPermissions(perms); } /** * Reads the space attributes of a file store. * *

The {@code store} parameter is a file store that supports the * {@link FileStoreSpaceAttributeView} providing access to the space related * attributes of the file store. It is implementation specific if all attributes * are read as an atomic operation with respect to other file system operations. * * @param store * The file store * * @return The file store space attributes * * @throws UnsupportedOperationException * If the file store space attribute view is not supported * @throws IOException * If an I/O error occurs * * @see FileStoreSpaceAttributeView#readAttributes() */ public static FileStoreSpaceAttributes readFileStoreSpaceAttributes(FileStore store) throws IOException { FileStoreSpaceAttributeView view = store.getFileStoreAttributeView(FileStoreSpaceAttributeView.class); if (view == null) throw new UnsupportedOperationException(); return view.readAttributes(); } }