492 lines
18 KiB
Java
492 lines
18 KiB
Java
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/*
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* Copyright (c) 1994, 2013, Oracle and/or its affiliates. All rights reserved.
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* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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*
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* This code is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License version 2 only, as
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* published by the Free Software Foundation. Oracle designates this
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* particular file as subject to the "Classpath" exception as provided
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* by Oracle in the LICENSE file that accompanied this code.
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*
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* This code is distributed in the hope that it will be useful, but WITHOUT
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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* version 2 for more details (a copy is included in the LICENSE file that
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* accompanied this code).
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*
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* You should have received a copy of the GNU General Public License version
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* 2 along with this work; if not, write to the Free Software Foundation,
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* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
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*
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* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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* or visit www.oracle.com if you need additional information or have any
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* questions.
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*/
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package java.io;
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import java.nio.channels.FileChannel;
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import sun.nio.ch.FileChannelImpl;
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import sun.misc.IoTrace;
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/**
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* A file output stream is an output stream for writing data to a
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* <code>File</code> or to a <code>FileDescriptor</code>. Whether or not
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* a file is available or may be created depends upon the underlying
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* platform. Some platforms, in particular, allow a file to be opened
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* for writing by only one <tt>FileOutputStream</tt> (or other
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* file-writing object) at a time. In such situations the constructors in
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* this class will fail if the file involved is already open.
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*
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* <p><code>FileOutputStream</code> is meant for writing streams of raw bytes
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* such as image data. For writing streams of characters, consider using
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* <code>FileWriter</code>.
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*
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* @author Arthur van Hoff
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* @see java.io.File
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* @see java.io.FileDescriptor
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* @see java.io.FileInputStream
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* @see java.nio.file.Files#newOutputStream
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* @since JDK1.0
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*/
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public
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class FileOutputStream extends OutputStream
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{
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/**
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* The system dependent file descriptor.
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*/
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private final FileDescriptor fd;
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/**
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* The path of the referenced file (null if the stream is created with a file descriptor)
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*/
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private final String path;
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/**
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* True if the file is opened for append.
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*/
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private final boolean append;
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/**
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* The associated channel, initalized lazily.
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*/
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private FileChannel channel;
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private final Object closeLock = new Object();
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private volatile boolean closed = false;
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private static final ThreadLocal<Boolean> runningFinalize =
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new ThreadLocal<>();
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private static boolean isRunningFinalize() {
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Boolean val;
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if ((val = runningFinalize.get()) != null)
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return val.booleanValue();
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return false;
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}
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/**
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* Creates a file output stream to write to the file with the
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* specified name. A new <code>FileDescriptor</code> object is
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* created to represent this file connection.
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* <p>
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* First, if there is a security manager, its <code>checkWrite</code>
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* method is called with <code>name</code> as its argument.
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* <p>
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* If the file exists but is a directory rather than a regular file, does
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* not exist but cannot be created, or cannot be opened for any other
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* reason then a <code>FileNotFoundException</code> is thrown.
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*
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* @param name the system-dependent filename
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* @exception FileNotFoundException if the file exists but is a directory
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* rather than a regular file, does not exist but cannot
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* be created, or cannot be opened for any other reason
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* @exception SecurityException if a security manager exists and its
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* <code>checkWrite</code> method denies write access
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* to the file.
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* @see java.lang.SecurityManager#checkWrite(java.lang.String)
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*/
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public FileOutputStream(String name) throws FileNotFoundException {
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this(name != null ? new File(name) : null, false);
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}
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/**
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* Creates a file output stream to write to the file with the specified
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* name. If the second argument is <code>true</code>, then
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* bytes will be written to the end of the file rather than the beginning.
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* A new <code>FileDescriptor</code> object is created to represent this
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* file connection.
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* <p>
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* First, if there is a security manager, its <code>checkWrite</code>
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* method is called with <code>name</code> as its argument.
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* <p>
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* If the file exists but is a directory rather than a regular file, does
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* not exist but cannot be created, or cannot be opened for any other
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* reason then a <code>FileNotFoundException</code> is thrown.
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*
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* @param name the system-dependent file name
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* @param append if <code>true</code>, then bytes will be written
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* to the end of the file rather than the beginning
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* @exception FileNotFoundException if the file exists but is a directory
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* rather than a regular file, does not exist but cannot
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* be created, or cannot be opened for any other reason.
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* @exception SecurityException if a security manager exists and its
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* <code>checkWrite</code> method denies write access
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* to the file.
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* @see java.lang.SecurityManager#checkWrite(java.lang.String)
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* @since JDK1.1
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*/
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public FileOutputStream(String name, boolean append)
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throws FileNotFoundException
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{
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this(name != null ? new File(name) : null, append);
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}
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/**
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* Creates a file output stream to write to the file represented by
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* the specified <code>File</code> object. A new
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* <code>FileDescriptor</code> object is created to represent this
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* file connection.
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* <p>
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* First, if there is a security manager, its <code>checkWrite</code>
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* method is called with the path represented by the <code>file</code>
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* argument as its argument.
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* <p>
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* If the file exists but is a directory rather than a regular file, does
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* not exist but cannot be created, or cannot be opened for any other
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* reason then a <code>FileNotFoundException</code> is thrown.
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*
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* @param file the file to be opened for writing.
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* @exception FileNotFoundException if the file exists but is a directory
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* rather than a regular file, does not exist but cannot
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* be created, or cannot be opened for any other reason
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* @exception SecurityException if a security manager exists and its
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* <code>checkWrite</code> method denies write access
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* to the file.
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* @see java.io.File#getPath()
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* @see java.lang.SecurityException
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* @see java.lang.SecurityManager#checkWrite(java.lang.String)
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*/
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public FileOutputStream(File file) throws FileNotFoundException {
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this(file, false);
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}
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/**
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* Creates a file output stream to write to the file represented by
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* the specified <code>File</code> object. If the second argument is
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* <code>true</code>, then bytes will be written to the end of the file
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* rather than the beginning. A new <code>FileDescriptor</code> object is
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* created to represent this file connection.
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* <p>
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* First, if there is a security manager, its <code>checkWrite</code>
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* method is called with the path represented by the <code>file</code>
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* argument as its argument.
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* <p>
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* If the file exists but is a directory rather than a regular file, does
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* not exist but cannot be created, or cannot be opened for any other
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* reason then a <code>FileNotFoundException</code> is thrown.
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*
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* @param file the file to be opened for writing.
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* @param append if <code>true</code>, then bytes will be written
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* to the end of the file rather than the beginning
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* @exception FileNotFoundException if the file exists but is a directory
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* rather than a regular file, does not exist but cannot
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* be created, or cannot be opened for any other reason
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* @exception SecurityException if a security manager exists and its
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* <code>checkWrite</code> method denies write access
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* to the file.
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* @see java.io.File#getPath()
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* @see java.lang.SecurityException
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* @see java.lang.SecurityManager#checkWrite(java.lang.String)
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* @since 1.4
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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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String name = (file != null ? file.getPath() : null);
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SecurityManager security = System.getSecurityManager();
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if (security != null) {
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security.checkWrite(name);
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}
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if (name == null) {
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throw new NullPointerException();
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}
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/*
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if (file.isInvalid()) {
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throw new FileNotFoundException("Invalid file path");
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}
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*/
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this.fd = new FileDescriptor();
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this.append = append;
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this.path = name;
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fd.incrementAndGetUseCount();
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open(name, append);
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}
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/**
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* Creates a file output stream to write to the specified file
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* descriptor, which represents an existing connection to an actual
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* file in the file system.
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* <p>
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* First, if there is a security manager, its <code>checkWrite</code>
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* method is called with the file descriptor <code>fdObj</code>
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* argument as its argument.
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* <p>
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* If <code>fdObj</code> is null then a <code>NullPointerException</code>
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* is thrown.
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* <p>
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* This constructor does not throw an exception if <code>fdObj</code>
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* is {@link java.io.FileDescriptor#valid() invalid}.
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* However, if the methods are invoked on the resulting stream to attempt
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* I/O on the stream, an <code>IOException</code> is thrown.
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*
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* @param fdObj the file descriptor to be opened for writing
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* @exception SecurityException if a security manager exists and its
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* <code>checkWrite</code> method denies
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* write access to the file descriptor
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* @see java.lang.SecurityManager#checkWrite(java.io.FileDescriptor)
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*/
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public FileOutputStream(FileDescriptor fdObj) {
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SecurityManager security = System.getSecurityManager();
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if (fdObj == null) {
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throw new NullPointerException();
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}
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if (security != null) {
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security.checkWrite(fdObj);
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}
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this.fd = fdObj;
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this.path = null;
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this.append = false;
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/*
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* FileDescriptor is being shared by streams.
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* Ensure that it's GC'ed only when all the streams/channels are done
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* using it.
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*/
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fd.incrementAndGetUseCount();
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}
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/**
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* Opens a file, with the specified name, for overwriting or appending.
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* @param name name of file to be opened
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* @param append whether the file is to be opened in append mode
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*/
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private void open(String name, boolean append)
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throws FileNotFoundException {
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if (append) {
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fd.openAppend(name);
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} else {
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fd.openWriteOnly(name);
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}
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}
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/**
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* Writes the specified byte to this file output stream.
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*
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* @param b the byte to be written.
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* @param append {@code true} if the write operation first
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* advances the position to the end of file
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*/
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private void write(int b, boolean append) throws IOException {
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fd.write(b);
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}
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/**
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* Writes the specified byte to this file output stream. Implements
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* the <code>write</code> method of <code>OutputStream</code>.
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*
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* @param b the byte to be written.
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* @exception IOException if an I/O error occurs.
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*/
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public void write(int b) throws IOException {
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Object traceContext = IoTrace.fileWriteBegin(path);
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int bytesWritten = 0;
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try {
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write(b, append);
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bytesWritten = 1;
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} finally {
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IoTrace.fileWriteEnd(traceContext, bytesWritten);
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}
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}
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/**
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* Writes a sub array as a sequence of bytes.
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* @param b the data to be written
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* @param off the start offset in the data
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* @param len the number of bytes that are written
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* @param append {@code true} to first advance the position to the
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* end of file
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* @exception IOException If an I/O error has occurred.
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*/
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private void writeBytes(byte b[], int off, int len, boolean append)
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throws IOException {
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fd.writeBytes(b, off, len);
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}
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/**
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* Writes <code>b.length</code> bytes from the specified byte array
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* to this file output stream.
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*
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* @param b the data.
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* @exception IOException if an I/O error occurs.
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*/
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public void write(byte b[]) throws IOException {
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Object traceContext = IoTrace.fileWriteBegin(path);
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int bytesWritten = 0;
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try {
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writeBytes(b, 0, b.length, append);
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bytesWritten = b.length;
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} finally {
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IoTrace.fileWriteEnd(traceContext, bytesWritten);
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}
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}
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/**
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* Writes <code>len</code> bytes from the specified byte array
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* starting at offset <code>off</code> to this file output stream.
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*
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* @param b the data.
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* @param off the start offset in the data.
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* @param len the number of bytes to write.
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* @exception IOException if an I/O error occurs.
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*/
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public void write(byte b[], int off, int len) throws IOException {
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Object traceContext = IoTrace.fileWriteBegin(path);
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int bytesWritten = 0;
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try {
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writeBytes(b, off, len, append);
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bytesWritten = len;
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} finally {
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IoTrace.fileWriteEnd(traceContext, bytesWritten);
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}
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}
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/**
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* Closes this file output stream and releases any system resources
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* associated with this stream. This file output stream may no longer
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* be used for writing bytes.
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*
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* <p> If this stream has an associated channel then the channel is closed
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* as well.
|
||
|
|
*
|
||
|
|
* @exception IOException if an I/O error occurs.
|
||
|
|
*
|
||
|
|
* @revised 1.4
|
||
|
|
* @spec JSR-51
|
||
|
|
*/
|
||
|
|
public void close() throws IOException {
|
||
|
|
synchronized (closeLock) {
|
||
|
|
if (closed) {
|
||
|
|
return;
|
||
|
|
}
|
||
|
|
closed = true;
|
||
|
|
}
|
||
|
|
|
||
|
|
if (channel != null) {
|
||
|
|
/*
|
||
|
|
* Decrement FD use count associated with the channel
|
||
|
|
* The use count is incremented whenever a new channel
|
||
|
|
* is obtained from this stream.
|
||
|
|
*/
|
||
|
|
fd.decrementAndGetUseCount();
|
||
|
|
channel.close();
|
||
|
|
}
|
||
|
|
|
||
|
|
/*
|
||
|
|
* Decrement FD use count associated with this stream
|
||
|
|
*/
|
||
|
|
int useCount = fd.decrementAndGetUseCount();
|
||
|
|
|
||
|
|
/*
|
||
|
|
* If FileDescriptor is still in use by another stream, the finalizer
|
||
|
|
* will not close it.
|
||
|
|
*/
|
||
|
|
if ((useCount <= 0) || !isRunningFinalize()) {
|
||
|
|
close0();
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
/**
|
||
|
|
* Returns the file descriptor associated with this stream.
|
||
|
|
*
|
||
|
|
* @return the <code>FileDescriptor</code> object that represents
|
||
|
|
* the connection to the file in the file system being used
|
||
|
|
* by this <code>FileOutputStream</code> object.
|
||
|
|
*
|
||
|
|
* @exception IOException if an I/O error occurs.
|
||
|
|
* @see java.io.FileDescriptor
|
||
|
|
*/
|
||
|
|
public final FileDescriptor getFD() throws IOException {
|
||
|
|
if (fd != null) return fd;
|
||
|
|
throw new IOException();
|
||
|
|
}
|
||
|
|
|
||
|
|
/**
|
||
|
|
* Returns the unique {@link java.nio.channels.FileChannel FileChannel}
|
||
|
|
* object associated with this file output stream. </p>
|
||
|
|
*
|
||
|
|
* <p> The initial {@link java.nio.channels.FileChannel#position()
|
||
|
|
* </code>position<code>} of the returned channel will be equal to the
|
||
|
|
* number of bytes written to the file so far unless this stream is in
|
||
|
|
* append mode, in which case it will be equal to the size of the file.
|
||
|
|
* Writing bytes to this stream will increment the channel's position
|
||
|
|
* accordingly. Changing the channel's position, either explicitly or by
|
||
|
|
* writing, will change this stream's file position.
|
||
|
|
*
|
||
|
|
* @return the file channel associated with this file output stream
|
||
|
|
*
|
||
|
|
* @since 1.4
|
||
|
|
* @spec JSR-51
|
||
|
|
*/
|
||
|
|
public FileChannel getChannel() {
|
||
|
|
synchronized (this) {
|
||
|
|
if (channel == null) {
|
||
|
|
channel = FileChannelImpl.open(fd, path, false, true, append, this);
|
||
|
|
|
||
|
|
/*
|
||
|
|
* Increment fd's use count. Invoking the channel's close()
|
||
|
|
* method will result in decrementing the use count set for
|
||
|
|
* the channel.
|
||
|
|
*/
|
||
|
|
fd.incrementAndGetUseCount();
|
||
|
|
}
|
||
|
|
return channel;
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
/**
|
||
|
|
* Cleans up the connection to the file, and ensures that the
|
||
|
|
* <code>close</code> method of this file output stream is
|
||
|
|
* called when there are no more references to this stream.
|
||
|
|
*
|
||
|
|
* @exception IOException if an I/O error occurs.
|
||
|
|
* @see java.io.FileInputStream#close()
|
||
|
|
*/
|
||
|
|
protected void finalize() throws IOException {
|
||
|
|
if (fd != null) {
|
||
|
|
if (fd == FileDescriptor.out || fd == FileDescriptor.err) {
|
||
|
|
flush();
|
||
|
|
} else {
|
||
|
|
|
||
|
|
/*
|
||
|
|
* Finalizer should not release the FileDescriptor if another
|
||
|
|
* stream is still using it. If the user directly invokes
|
||
|
|
* close() then the FileDescriptor is also released.
|
||
|
|
*/
|
||
|
|
runningFinalize.set(Boolean.TRUE);
|
||
|
|
try {
|
||
|
|
close();
|
||
|
|
} finally {
|
||
|
|
runningFinalize.set(Boolean.FALSE);
|
||
|
|
}
|
||
|
|
}
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
private void close0() throws IOException
|
||
|
|
{
|
||
|
|
fd.close();
|
||
|
|
}
|
||
|
|
|
||
|
|
}
|