/*

 * Copyright (c) 1996, 2006, 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.charset.Charset;

/**

 * 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 <code>charset</code>}.  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.  The size of

 * this buffer may be specified, but by default it is large enough for most

 * purposes.  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

 * <tt>char</tt> 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       JDK1.1

 */

public class OutputStreamWriter extends Writer {

    /**

     * Creates an OutputStreamWriter that uses the named charset.

     *

     * @param  out

     *         An OutputStream

     *

     * @param  charsetName

     *         The name of a supported

     *         {@link java.nio.charset.Charset </code>charset<code>}

     *

     * @exception  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");

        if (!charsetName.toUpperCase().equals("UTF-8")) {

            throw new UnsupportedEncodingException(charsetName);

        }

    }

    /**

     * Creates an OutputStreamWriter that uses the default character encoding.

     *

     * @param  out  An OutputStream

     */

    public OutputStreamWriter(OutputStream out) {

        super(out);

    }

    /**

     * Creates an OutputStreamWriter that uses the given charset. </p>

     *

     * @param  out

     *         An OutputStream

     *

     * @param  cs

     *         A charset

     *

     * @since 1.4

     * @spec JSR-51

     */

    public OutputStreamWriter(OutputStream out, Charset cs) {

        this(out);

    }

    /**

     * Creates an OutputStreamWriter that uses the given charset encoder.  </p>

     *

     * @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 <tt>null</tt> if the stream has

     * been closed. </p>

     *

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

     *         <code>null</code> if the stream has been closed

     *

     * @see java.nio.charset.Charset

     *

     * @revised 1.4

     * @spec JSR-51

     */

    public String getEncoding() {

        return "UTF-8";

    }

    /**

     * 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 {

        out().flush();

    }

    /**

     * Writes a single character.

     *

     * @exception  IOException  If an I/O error occurs

     */

    public void write(int c) throws IOException {

        if (c <= 0x7F) {

            out().write(c);

        } else if (c <= 0x7FF) {

            out().write(0xC0 | (c >> 6));

            out().write(0x80 | (c & 0x3F));

        } else {

            out().write(0xE0 | (c >> 12));

            out().write(0x80 | ((c >> 6) & 0x3F));

            out().write(0x80 | (c & 0x3F));

        }

    }

    /**

     * 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

     *

     * @exception  IOException  If an I/O error occurs

     */

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

        while (len-- > 0) {

            write(cbuf[off++]);

        }

    }

    /**

     * 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

     *

     * @exception  IOException  If an I/O error occurs

     */

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

        while (len-- > 0) {

            write(str.charAt(off++));

        }

    }

    /**

     * Flushes the stream.

     *

     * @exception  IOException  If an I/O error occurs

     */

    public void flush() throws IOException {

        out().flush();

    }

    public void close() throws IOException {

        out().close();

    }

    private OutputStream out() {

        return (OutputStream) lock;

    }

}