| /* FileDescriptor.java -- Opaque file handle class |
| Copyright (C) 1998, 1999, 2000, 2001, 2002, 2003, 2004 |
| Free Software Foundation, Inc. |
| |
| This file is part of GNU Classpath. |
| |
| GNU Classpath is free software; you can redistribute it and/or modify |
| it under the terms of the GNU General Public License as published by |
| the Free Software Foundation; either version 2, or (at your option) |
| any later version. |
| |
| GNU Classpath 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 for more details. |
| |
| You should have received a copy of the GNU General Public License |
| along with GNU Classpath; see the file COPYING. If not, write to the |
| Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA |
| 02110-1301 USA. |
| |
| Linking this library statically or dynamically with other modules is |
| making a combined work based on this library. Thus, the terms and |
| conditions of the GNU General Public License cover the whole |
| combination. |
| |
| As a special exception, the copyright holders of this library give you |
| permission to link this library with independent modules to produce an |
| executable, regardless of the license terms of these independent |
| modules, and to copy and distribute the resulting executable under |
| terms of your choice, provided that you also meet, for each linked |
| independent module, the terms and conditions of the license of that |
| module. An independent module is a module which is not derived from |
| or based on this library. If you modify this library, you may extend |
| this exception to your version of the library, but you are not |
| obligated to do so. If you do not wish to do so, delete this |
| exception statement from your version. */ |
| |
| |
| package java.io; |
| |
| import gnu.java.nio.channels.FileChannelImpl; |
| |
| import java.nio.channels.ByteChannel; |
| import java.nio.channels.FileChannel; |
| |
| /** |
| * This class represents an opaque file handle as a Java class. It should |
| * be used only to pass to other methods that expect an object of this |
| * type. No system specific information can be obtained from this object. |
| * |
| * @author Aaron M. Renn (arenn@urbanophile.com) |
| * @author Tom Tromey (tromey@cygnus.com) |
| * @date September 24, 1998 |
| */ |
| public final class FileDescriptor |
| { |
| /** |
| * A <code>FileDescriptor</code> representing the system standard input |
| * stream. This will usually be accessed through the |
| * <code>System.in</code>variable. |
| */ |
| public static final FileDescriptor in |
| = new FileDescriptor (FileChannelImpl.in); |
| |
| /** |
| * A <code>FileDescriptor</code> representing the system standard output |
| * stream. This will usually be accessed through the |
| * <code>System.out</code>variable. |
| */ |
| public static final FileDescriptor out |
| = new FileDescriptor (FileChannelImpl.out); |
| |
| /** |
| * A <code>FileDescriptor</code> representing the system standard error |
| * stream. This will usually be accessed through the |
| * <code>System.err</code>variable. |
| */ |
| public static final FileDescriptor err |
| = new FileDescriptor (FileChannelImpl.err); |
| |
| final ByteChannel channel; |
| |
| /** |
| * This method is used to initialize an invalid FileDescriptor object. |
| */ |
| public FileDescriptor() |
| { |
| channel = null; |
| } |
| |
| /** |
| * This method is used to initialize a FileDescriptor object. |
| */ |
| FileDescriptor(ByteChannel channel) |
| { |
| this.channel = channel; |
| } |
| |
| |
| /** |
| * This method forces all data that has not yet been physically written to |
| * the underlying storage medium associated with this |
| * <code>FileDescriptor</code> |
| * to be written out. This method will not return until all data has |
| * been fully written to the underlying device. If the device does not |
| * support this functionality or if an error occurs, then an exception |
| * will be thrown. |
| */ |
| public void sync () throws SyncFailedException |
| { |
| if (channel instanceof FileChannel) |
| { |
| try |
| { |
| ((FileChannel) channel).force(true); |
| } |
| catch (IOException ex) |
| { |
| if (ex instanceof SyncFailedException) |
| throw (SyncFailedException) ex; |
| else |
| throw new SyncFailedException(ex.toString()); |
| } |
| } |
| } |
| |
| /** |
| * This methods tests whether or not this object represents a valid open |
| * native file handle. |
| * |
| * @return <code>true</code> if this object represents a valid |
| * native file handle, <code>false</code> otherwise |
| */ |
| public boolean valid () |
| { |
| return channel != null && channel.isOpen(); |
| } |
| } |