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	/*
	* Copyright (c) 1994, 2021, Oracle and/or its affiliates. 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. Oracle designates this
	* particular file as subject to the "Classpath" exception as provided
	* by Oracle 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 Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
	* or visit www.oracle.com if you need additional information or have any
	* questions.
	*/

	package java.io;

	import java.nio.channels.FileChannel;
	import jdk.internal.access.SharedSecrets;
	import jdk.internal.access.JavaIOFileDescriptorAccess;
	import sun.nio.ch.FileChannelImpl;


	/**
	* A file output stream is an output stream for writing data to a
	* {@code File} or to a {@code FileDescriptor}. Whether or not
	* a file is available or may be created depends upon the underlying
	* platform. Some platforms, in particular, allow a file to be opened
	* for writing by only one {@code FileOutputStream} (or other
	* file-writing object) at a time. In such situations the constructors in
	* this class will fail if the file involved is already open.
	*
	* <p>{@code FileOutputStream} is meant for writing streams of raw bytes
	* such as image data. For writing streams of characters, consider using
	* {@code FileWriter}.
	*
	* @apiNote
	* To release resources used by this stream {@link #close} should be called
	* directly or by try-with-resources. Subclasses are responsible for the cleanup
	* of resources acquired by the subclass.
	* Subclasses that override {@link #finalize} in order to perform cleanup
	* should be modified to use alternative cleanup mechanisms such as
	* {@link java.lang.ref.Cleaner} and remove the overriding {@code finalize} method.
	*
	* @implSpec
	* If this FileOutputStream has been subclassed and the {@link #close}
	* method has been overridden, the {@link #close} method will be
	* called when the FileInputStream is unreachable.
	* Otherwise, it is implementation specific how the resource cleanup described in
	* {@link #close} is performed.
	*
	* @author Arthur van Hoff
	* @see java.io.File
	* @see java.io.FileDescriptor
	* @see java.io.FileInputStream
	* @see java.nio.file.Files#newOutputStream
	* @since 1.0
	*/
	public class FileOutputStream extends OutputStream
	{
	/**
	* Access to FileDescriptor internals.
	*/
	private static final JavaIOFileDescriptorAccess fdAccess =
	SharedSecrets.getJavaIOFileDescriptorAccess();

	/**
	* The system dependent file descriptor.
	*/
	private final FileDescriptor fd;

	/**
	* The associated channel, initialized lazily.
	*/
	private volatile FileChannel channel;

	/**
	* The path of the referenced file
	* (null if the stream is created with a file descriptor)
	*/
	private final String path;

	private final Object closeLock = new Object();

	private volatile boolean closed;

	/**
	* Creates a file output stream to write to the file with the
	* specified name. A new {@code FileDescriptor} object is
	* created to represent this file connection.
	* <p>
	* First, if there is a security manager, its {@code checkWrite}
	* method is called with {@code name} as its argument.
	* <p>
	* If the file exists but is a directory rather than a regular file, does
	* not exist but cannot be created, or cannot be opened for any other
	* reason then a {@code FileNotFoundException} is thrown.
	*
	* @implSpec Invoking this constructor with the parameter {@code name} is
	* equivalent to invoking {@link #FileOutputStream(String,boolean)
	* new FileOutputStream(name, false)}.
	*
	* @param name the system-dependent filename
	* @throws FileNotFoundException if the file exists but is a directory
	* rather than a regular file, does not exist but cannot
	* be created, or cannot be opened for any other reason
	* @throws SecurityException if a security manager exists and its
	* {@code checkWrite} method denies write access
	* to the file.
	* @see java.lang.SecurityManager#checkWrite(java.lang.String)
	*/
	public FileOutputStream(String name) throws FileNotFoundException {
	this(name != null ? new File(name) : null, false);
	}

	/**
	* Creates a file output stream to write to the file with the specified
	* name. If the second argument is {@code true}, then
	* bytes will be written to the end of the file rather than the beginning.
	* A new {@code FileDescriptor} object is created to represent this
	* file connection.
	* <p>
	* First, if there is a security manager, its {@code checkWrite}
	* method is called with {@code name} as its argument.
	* <p>
	* If the file exists but is a directory rather than a regular file, does
	* not exist but cannot be created, or cannot be opened for any other
	* reason then a {@code FileNotFoundException} is thrown.
	*
	* @param name the system-dependent file name
	* @param append if {@code true}, then bytes will be written
	* to the end of the file rather than the beginning
	* @throws FileNotFoundException if the file exists but is a directory
	* rather than a regular file, does not exist but cannot
	* be created, or cannot be opened for any other reason.
	* @throws SecurityException if a security manager exists and its
	* {@code checkWrite} method denies write access
	* to the file.
	* @see java.lang.SecurityManager#checkWrite(java.lang.String)
	* @since 1.1
	*/
	public FileOutputStream(String name, boolean append)
	throws FileNotFoundException
	{
	this(name != null ? new File(name) : null, append);
	}

	/**
	* Creates a file output stream to write to the file represented by
	* the specified {@code File} object. A new
	* {@code FileDescriptor} object is created to represent this
	* file connection.
	* <p>
	* First, if there is a security manager, its {@code checkWrite}
	* method is called with the path represented by the {@code file}
	* argument as its argument.
	* <p>
	* If the file exists but is a directory rather than a regular file, does
	* not exist but cannot be created, or cannot be opened for any other
	* reason then a {@code FileNotFoundException} is thrown.
	*
	* @param file the file to be opened for writing.
	* @throws FileNotFoundException if the file exists but is a directory
	* rather than a regular file, does not exist but cannot
	* be created, or cannot be opened for any other reason
	* @throws SecurityException if a security manager exists and its
	* {@code checkWrite} method denies write access
	* to the file.
	* @see java.io.File#getPath()
	* @see java.lang.SecurityException
	* @see java.lang.SecurityManager#checkWrite(java.lang.String)
	*/
	public FileOutputStream(File file) throws FileNotFoundException {
	this(file, false);
	}

	/**
	* Creates a file output stream to write to the file represented by
	* the specified {@code File} object. If the second argument is
	* {@code true}, then bytes will be written to the end of the file
	* rather than the beginning. A new {@code FileDescriptor} object is
	* created to represent this file connection.
	* <p>
	* First, if there is a security manager, its {@code checkWrite}
	* method is called with the path represented by the {@code file}
	* argument as its argument.
	* <p>
	* If the file exists but is a directory rather than a regular file, does
	* not exist but cannot be created, or cannot be opened for any other
	* reason then a {@code FileNotFoundException} is thrown.
	*
	* @param file the file to be opened for writing.
	* @param append if {@code true}, then bytes will be written
	* to the end of the file rather than the beginning
	* @throws FileNotFoundException if the file exists but is a directory
	* rather than a regular file, does not exist but cannot
	* be created, or cannot be opened for any other reason
	* @throws SecurityException if a security manager exists and its
	* {@code checkWrite} method denies write access
	* to the file.
	* @see java.io.File#getPath()
	* @see java.lang.SecurityException
	* @see java.lang.SecurityManager#checkWrite(java.lang.String)
	* @since 1.4
	*/
	public FileOutputStream(File file, boolean append)
	throws FileNotFoundException
	{
	String name = (file != null ? file.getPath() : null);
	@SuppressWarnings("removal")
	SecurityManager security = System.getSecurityManager();
	if (security != null) {
	security.checkWrite(name);
	}
	if (name == null) {
	throw new NullPointerException();
	}
	if (file.isInvalid()) {
	throw new FileNotFoundException("Invalid file path");
	}
	this.fd = new FileDescriptor();
	fd.attach(this);
	this.path = name;

	open(name, append);
	FileCleanable.register(fd); // open sets the fd, register the cleanup
	}

	/**
	* Creates a file output stream to write to the specified file
	* descriptor, which represents an existing connection to an actual
	* file in the file system.
	* <p>
	* First, if there is a security manager, its {@code checkWrite}
	* method is called with the file descriptor {@code fdObj}
	* argument as its argument.
	* <p>
	* If {@code fdObj} is null then a {@code NullPointerException}
	* is thrown.
	* <p>
	* This constructor does not throw an exception if {@code fdObj}
	* is {@link java.io.FileDescriptor#valid() invalid}.
	* However, if the methods are invoked on the resulting stream to attempt
	* I/O on the stream, an {@code IOException} is thrown.
	*
	* @param fdObj the file descriptor to be opened for writing
	* @throws SecurityException if a security manager exists and its
	* {@code checkWrite} method denies
	* write access to the file descriptor
	* @see java.lang.SecurityManager#checkWrite(java.io.FileDescriptor)
	*/
	public FileOutputStream(FileDescriptor fdObj) {
	@SuppressWarnings("removal")
	SecurityManager security = System.getSecurityManager();
	if (fdObj == null) {
	throw new NullPointerException();
	}
	if (security != null) {
	security.checkWrite(fdObj);
	}
	this.fd = fdObj;
	this.path = null;

	fd.attach(this);
	}

	/**
	* Opens a file, with the specified name, for overwriting or appending.
	* @param name name of file to be opened
	* @param append whether the file is to be opened in append mode
	*/
	private native void open0(String name, boolean append)
	throws FileNotFoundException;

	// wrap native call to allow instrumentation
	/**
	* Opens a file, with the specified name, for overwriting or appending.
	* @param name name of file to be opened
	* @param append whether the file is to be opened in append mode
	*/
	private void open(String name, boolean append)
	throws FileNotFoundException {
	open0(name, append);
	}

	/**
	* Writes the specified byte to this file output stream.
	*
	* @param b the byte to be written.
	* @param append {@code true} if the write operation first
	* advances the position to the end of file
	*/
	private native void write(int b, boolean append) throws IOException;

	/**
	* Writes the specified byte to this file output stream. Implements
	* the {@code write} method of {@code OutputStream}.
	*
	* @param b the byte to be written.
	* @throws IOException if an I/O error occurs.
	*/
	public void write(int b) throws IOException {
	write(b, fdAccess.getAppend(fd));
	}

	/**
	* Writes a sub array as a sequence of bytes.
	* @param b the data to be written
	* @param off the start offset in the data
	* @param len the number of bytes that are written
	* @param append {@code true} to first advance the position to the
	* end of file
	* @throws IOException If an I/O error has occurred.
	*/
	private native void writeBytes(byte b[], int off, int len, boolean append)
	throws IOException;

	/**
	* Writes {@code b.length} bytes from the specified byte array
	* to this file output stream.
	*
	* @param b the data.
	* @throws IOException if an I/O error occurs.
	*/
	public void write(byte b[]) throws IOException {
	writeBytes(b, 0, b.length, fdAccess.getAppend(fd));
	}

	/**
	* Writes {@code len} bytes from the specified byte array
	* starting at offset {@code off} to this file output stream.
	*
	* @param b the data.
	* @param off the start offset in the data.
	* @param len the number of bytes to write.
	* @throws IOException if an I/O error occurs.
	*/
	public void write(byte b[], int off, int len) throws IOException {
	writeBytes(b, off, len, fdAccess.getAppend(fd));
	}

	/**
	* Closes this file output stream and releases any system resources
	* associated with this stream. This file output stream may no longer
	* be used for writing bytes.
	*
	* <p> If this stream has an associated channel then the channel is closed
	* as well.
	*
	* @apiNote
	* Overriding {@link #close} to perform cleanup actions is reliable
	* only when called directly or when called by try-with-resources.
	* Do not depend on finalization to invoke {@code close};
	* finalization is not reliable and is deprecated.
	* If cleanup of native resources is needed, other mechanisms such as
	* {@linkplain java.lang.ref.Cleaner} should be used.
	*
	* @throws IOException if an I/O error occurs.
	*
	* @revised 1.4
	*/
	public void close() throws IOException {
	if (closed) {
	return;
	}
	synchronized (closeLock) {
	if (closed) {
	return;
	}
	closed = true;
	}

	FileChannel fc = channel;
	if (fc != null) {
	// possible race with getChannel(), benign since
	// FileChannel.close is final and idempotent
	fc.close();
	}

	fd.closeAll(new Closeable() {
	public void close() throws IOException {
	fd.close();
	}
	});
	}

	/**
	* Returns the file descriptor associated with this stream.
	*
	* @return the {@code FileDescriptor} object that represents
	* the connection to the file in the file system being used
	* by this {@code FileOutputStream} object.
	*
	* @throws 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> The initial {@link java.nio.channels.FileChannel#position()
	* position} 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
	*/
	public FileChannel getChannel() {
	FileChannel fc = this.channel;
	if (fc == null) {
	synchronized (this) {
	fc = this.channel;
	if (fc == null) {
	this.channel = fc = FileChannelImpl.open(fd, path, false,
	true, false, this);
	if (closed) {
	try {
	// possible race with close(), benign since
	// FileChannel.close is final and idempotent
	fc.close();
	} catch (IOException ioe) {
	throw new InternalError(ioe); // should not happen
	}
	}
	}
	}
	}
	return fc;
	}

	private static native void initIDs();

	static {
	initIDs();
	}
	}

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