/*

  * 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;

     }

 }