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jlechner |
/* FileOutputStream.java -- Writes to a file on disk.
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Copyright (C) 1998, 2001, 2003, 2004, 2005 Free Software Foundation, Inc.
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This file is part of GNU Classpath.
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GNU Classpath is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2, or (at your option)
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any later version.
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GNU Classpath is distributed in the hope that it will be useful, but
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WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with GNU Classpath; see the file COPYING. If not, write to the
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Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
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02110-1301 USA.
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Linking this library statically or dynamically with other modules is
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making a combined work based on this library. Thus, the terms and
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conditions of the GNU General Public License cover the whole
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combination.
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As a special exception, the copyright holders of this library give you
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permission to link this library with independent modules to produce an
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executable, regardless of the license terms of these independent
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modules, and to copy and distribute the resulting executable under
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terms of your choice, provided that you also meet, for each linked
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independent module, the terms and conditions of the license of that
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module. An independent module is a module which is not derived from
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or based on this library. If you modify this library, you may extend
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this exception to your version of the library, but you are not
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obligated to do so. If you do not wish to do so, delete this
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exception statement from your version. */
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package java.io;
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import gnu.java.nio.channels.FileChannelImpl;
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import java.nio.channels.FileChannel;
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/* Written using "Java Class Libraries", 2nd edition, ISBN 0-201-31002-3
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* "The Java Language Specification", ISBN 0-201-63451-1
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* Status: Complete to version 1.1.
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*/
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/**
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* This classes allows a stream of data to be written to a disk file or
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* any open <code>FileDescriptor</code>.
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*
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* @author Aaron M. Renn (arenn@urbanophile.com)
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* @author Tom Tromey (tromey@cygnus.com)
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*/
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public class FileOutputStream extends OutputStream
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{
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private FileDescriptor fd;
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private FileChannelImpl ch;
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/**
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* This method initializes a <code>FileOutputStream</code> object to write
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* to the named file. The file is created if it does not exist, and
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* the bytes written are written starting at the beginning of the file if
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* the <code>append</code> argument is <code>false</code> or at the end
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* of the file if the <code>append</code> argument is true.
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* <p>
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* Before opening a file, a security check is performed by calling the
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* <code>checkWrite</code> method of the <code>SecurityManager</code> (if
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* one exists) with the name of the file to be opened. An exception is
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* thrown if writing is not allowed.
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*
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* @param path The name of the file this stream should write to
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* @param append <code>true</code> to append bytes to the end of the file,
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* or <code>false</code> to write bytes to the beginning
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*
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* @exception SecurityException If write access to the file is not allowed
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* @exception FileNotFoundException If a non-security error occurs
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*/
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public FileOutputStream (String path, boolean append)
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throws SecurityException, FileNotFoundException
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{
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this (new File(path), append);
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}
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/**
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* This method initializes a <code>FileOutputStream</code> object to write
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* to the named file. The file is created if it does not exist, and
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* the bytes written are written starting at the beginning of the file.
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* <p>
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* Before opening a file, a security check is performed by calling the
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* <code>checkWrite</code> method of the <code>SecurityManager</code> (if
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* one exists) with the name of the file to be opened. An exception is
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* thrown if writing is not allowed.
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*
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* @param path The name of the file this stream should write to
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*
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* @exception SecurityException If write access to the file is not allowed
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* @exception FileNotFoundException If a non-security error occurs
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*/
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public FileOutputStream (String path)
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throws SecurityException, FileNotFoundException
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{
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this (path, false);
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}
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/**
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* This method initializes a <code>FileOutputStream</code> object to write
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* to the specified <code>File</code> object. The file is created if it
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* does not exist, and the bytes written are written starting at the
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* beginning of the file.
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* <p>
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* Before opening a file, a security check is performed by calling the
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* <code>checkWrite</code> method of the <code>SecurityManager</code> (if
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* one exists) with the name of the file to be opened. An exception is
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* thrown if writing is not allowed.
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*
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* @param file The <code>File</code> object this stream should write to
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*
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* @exception SecurityException If write access to the file is not allowed
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* @exception FileNotFoundException If a non-security error occurs
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*/
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public FileOutputStream (File file)
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throws SecurityException, FileNotFoundException
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{
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this (file, false);
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}
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/**
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* This method initializes a <code>FileOutputStream</code> object to write
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* to the specified <code>File</code> object. The file is created if it
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* does not exist, and the bytes written are written starting at the
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* beginning of the file if the <code>append</code> parameter is
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* <code>false</code>. Otherwise bytes are written at the end of the
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* file.
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* <p>
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* Before opening a file, a security check is performed by calling the
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* <code>checkWrite</code> method of the <code>SecurityManager</code> (if
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* one exists) with the name of the file to be opened. An exception is
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* thrown if writing is not allowed.
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*
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* @param file The <code>File</code> object this stream should write to
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* @param append <code>true</code> to append bytes to the end of the file,
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* or <code>false</code> to write bytes to the beginning
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*
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* @exception SecurityException If write access to the file is not allowed
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* @exception FileNotFoundException If a non-security error occurs
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*/
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public FileOutputStream (File file, boolean append)
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throws FileNotFoundException
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{
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SecurityManager s = System.getSecurityManager();
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if (s != null)
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s.checkWrite(file.getPath());
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ch = FileChannelImpl.create(file, (append
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? FileChannelImpl.WRITE
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| FileChannelImpl.APPEND
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: FileChannelImpl.WRITE));
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}
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/**
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* This method initializes a <code>FileOutputStream</code> object to write
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* to the file represented by the specified <code>FileDescriptor</code>
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* object. This method does not create any underlying disk file or
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* reposition the file pointer of the given descriptor. It assumes that
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* this descriptor is ready for writing as is.
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* <p>
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* Before opening a file, a security check is performed by calling the
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* <code>checkWrite</code> method of the <code>SecurityManager</code> (if
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* one exists) with the specified <code>FileDescriptor</code> as an argument.
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* An exception is thrown if writing is not allowed.
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*
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* @param fdObj The <code>FileDescriptor</code> this stream should write to
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*
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* @exception SecurityException If write access to the file is not allowed
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*/
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public FileOutputStream (FileDescriptor fdObj)
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throws SecurityException
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{
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// Hmm, no other exception but this one to throw, but if the descriptor
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// isn't valid, we surely don't have "permission" to write to it.
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if (!fdObj.valid())
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throw new SecurityException("Invalid FileDescriptor");
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SecurityManager s = System.getSecurityManager();
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if (s != null)
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s.checkWrite(fdObj);
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fd = fdObj;
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ch = (FileChannelImpl) fdObj.channel;
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}
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FileOutputStream(FileChannelImpl ch)
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{
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this.ch = ch;
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}
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protected void finalize () throws IOException
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{
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// We don't actually need this, but we include it because it is
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// mentioned in the JCL.
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}
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/**
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* This method returns a <code>FileDescriptor</code> object representing
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* the file that is currently being written to
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*
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* @return A <code>FileDescriptor</code> object for this stream
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*
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* @exception IOException If an error occurs
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*/
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public final FileDescriptor getFD () throws IOException
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{
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synchronized (this)
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{
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if (fd == null)
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fd = new FileDescriptor (ch);
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return fd;
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}
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}
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/**
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* This method writes a single byte of data to the file.
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*
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* @param b The byte of data to write, passed as an <code>int</code>
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*
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* @exception IOException If an error occurs
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*/
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public void write (int b) throws IOException
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{
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ch.write (b);
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}
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/**
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* This method writes all the bytes in the specified array to the
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* file.
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*
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* @param buf The array of bytes to write to the file
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*
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* @exception IOException If an error occurs
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*/
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public void write (byte[] buf)
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throws IOException
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{
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write (buf, 0, buf.length);
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}
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/**
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* This method writes <code>len</code> bytes from the byte array
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* <code>buf</code> to the file starting at index <code>offset</code>.
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*
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* @param buf The array of bytes to write to the file
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* @param offset The offset into the array to start writing bytes from
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* @param len The number of bytes to write to the file
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*
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* @exception IOException If an error occurs
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*/
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public void write (byte[] buf, int offset, int len)
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throws IOException
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{
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if (offset < 0
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|| len < 0
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|| offset + len > buf.length)
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throw new ArrayIndexOutOfBoundsException ();
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ch.write (buf, offset, len);
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}
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/**
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* This method closes the underlying file. Any further attempts to
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* write to this stream will likely generate an exception since the
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* file is closed.
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*
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* @exception IOException If an error occurs
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*/
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public void close () throws IOException
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{
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ch.close();
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}
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/**
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* This method creates a java.nio.channels.FileChannel.
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* Nio does not allow one to create a file channel directly.
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* A file channel must be created by first creating an instance of
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* Input/Output/RandomAccessFile and invoking the getChannel() method on it.
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*/
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public synchronized FileChannel getChannel()
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{
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return ch;
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}
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} // class FileOutputStream
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