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 * Copyright (c) 1996, 2019, 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

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 * questions.

 */

package java.io;

import java.nio.CharBuffer;

import java.nio.charset.Charset;

import java.nio.charset.CharsetEncoder;

import sun.nio.cs.StreamEncoder;

/**

 * An OutputStreamWriter is a bridge from character streams to byte streams:

 * Characters written to it are encoded into bytes using a specified {@link

 * java.nio.charset.Charset charset}.  The charset that it uses

 * may be specified by name or may be given explicitly, or the platform's

 * default charset may be accepted.

 *

 * <p> Each invocation of a write() method causes the encoding converter to be

 * invoked on the given character(s).  The resulting bytes are accumulated in a

 * buffer before being written to the underlying output stream.  Note that the

 * characters passed to the write() methods are not buffered.

 *

 * <p> For top efficiency, consider wrapping an OutputStreamWriter within a

 * BufferedWriter so as to avoid frequent converter invocations.  For example:

 *

 * <pre>

 * Writer out

 *   = new BufferedWriter(new OutputStreamWriter(System.out));

 * </pre>

 *

 * <p> A <i>surrogate pair</i> is a character represented by a sequence of two

 * {@code char} values: A <i>high</i> surrogate in the range '&#92;uD800' to

 * '&#92;uDBFF' followed by a <i>low</i> surrogate in the range '&#92;uDC00' to

 * '\uDFFF'.

 *

 * <p> A <i>malformed surrogate element</i> is a high surrogate that is not

 * followed by a low surrogate or a low surrogate that is not preceded by a

 * high surrogate.

 *

 * <p> This class always replaces malformed surrogate elements and unmappable

 * character sequences with the charset's default <i>substitution sequence</i>.

 * The {@linkplain java.nio.charset.CharsetEncoder} class should be used when more

 * control over the encoding process is required.

 *

 * @see BufferedWriter

 * @see OutputStream

 * @see java.nio.charset.Charset

 *

 * @author      Mark Reinhold

 * @since       1.1

 */

public class OutputStreamWriter extends Writer {

    private final StreamEncoder se;

    /**

     * Creates an OutputStreamWriter that uses the named charset.

     *

     * @param  out

     *         An OutputStream

     *

     * @param  charsetName

     *         The name of a supported

     *         {@link java.nio.charset.Charset charset}

     *

     * @throws     UnsupportedEncodingException

     *             If the named encoding is not supported

     */

    public OutputStreamWriter(OutputStream out, String charsetName)

        throws UnsupportedEncodingException

    {

        super(out);

        if (charsetName == null)

            throw new NullPointerException("charsetName");

        se = StreamEncoder.forOutputStreamWriter(out, this, charsetName);

    }

    /**

     * Creates an OutputStreamWriter that uses the default character encoding.

     *

     * @param  out  An OutputStream

     */

    public OutputStreamWriter(OutputStream out) {

        super(out);

        try {

            se = StreamEncoder.forOutputStreamWriter(out, this, (String)null);

        } catch (UnsupportedEncodingException e) {

            throw new Error(e);

        }

    }

    /**

     * Creates an OutputStreamWriter that uses the given charset.

     *

     * @param  out

     *         An OutputStream

     *

     * @param  cs

     *         A charset

     *

     * @since 1.4

     * @spec JSR-51

     */

    public OutputStreamWriter(OutputStream out, Charset cs) {

        super(out);

        if (cs == null)

            throw new NullPointerException("charset");

        se = StreamEncoder.forOutputStreamWriter(out, this, cs);

    }

    /**

     * Creates an OutputStreamWriter that uses the given charset encoder.

     *

     * @param  out

     *         An OutputStream

     *

     * @param  enc

     *         A charset encoder

     *

     * @since 1.4

     * @spec JSR-51

     */

    public OutputStreamWriter(OutputStream out, CharsetEncoder enc) {

        super(out);

        if (enc == null)

            throw new NullPointerException("charset encoder");

        se = StreamEncoder.forOutputStreamWriter(out, this, enc);

    }

    /**

     * Returns the name of the character encoding being used by this stream.

     *

     * <p> If the encoding has an historical name then that name is returned;

     * otherwise the encoding's canonical name is returned.

     *

     * <p> If this instance was created with the {@link

     * #OutputStreamWriter(OutputStream, String)} constructor then the returned

     * name, being unique for the encoding, may differ from the name passed to

     * the constructor.  This method may return {@code null} if the stream has

     * been closed. </p>

     *

     * @return The historical name of this encoding, or possibly

     *         {@code null} if the stream has been closed

     *

     * @see java.nio.charset.Charset

     *

     * @revised 1.4

     * @spec JSR-51

     */

    public String getEncoding() {

        return se.getEncoding();

    }

    /**

     * Flushes the output buffer to the underlying byte stream, without flushing

     * the byte stream itself.  This method is non-private only so that it may

     * be invoked by PrintStream.

     */

    void flushBuffer() throws IOException {

        se.flushBuffer();

    }

    /**

     * Writes a single character.

     *

     * @throws     IOException  If an I/O error occurs

     */

    public void write(int c) throws IOException {

        se.write(c);

    }

    /**

     * Writes a portion of an array of characters.

     *

     * @param  cbuf  Buffer of characters

     * @param  off   Offset from which to start writing characters

     * @param  len   Number of characters to write

     *

     * @throws  IndexOutOfBoundsException

     *          If {@code off} is negative, or {@code len} is negative,

     *          or {@code off + len} is negative or greater than the length

     *          of the given array

     *

     * @throws  IOException  If an I/O error occurs

     */

    public void write(char cbuf[], int off, int len) throws IOException {

        se.write(cbuf, off, len);

    }

    /**

     * Writes a portion of a string.

     *

     * @param  str  A String

     * @param  off  Offset from which to start writing characters

     * @param  len  Number of characters to write

     *

     * @throws  IndexOutOfBoundsException

     *          If {@code off} is negative, or {@code len} is negative,

     *          or {@code off + len} is negative or greater than the length

     *          of the given string

     *

     * @throws  IOException  If an I/O error occurs

     */

    public void write(String str, int off, int len) throws IOException {

        se.write(str, off, len);

    }

    @Override

    public Writer append(CharSequence csq, int start, int end) throws IOException {

        if (csq == null) csq = "null";

        return append(csq.subSequence(start, end));

    }

    @Override

    public Writer append(CharSequence csq) throws IOException {

        if (csq instanceof CharBuffer) {

            se.write((CharBuffer) csq);

        } else {

            se.write(String.valueOf(csq));

        }

        return this;

    }

    /**

     * Flushes the stream.

     *

     * @throws     IOException  If an I/O error occurs

     */

    public void flush() throws IOException {

        se.flush();

    }

    public void close() throws IOException {

        se.close();

    }

}