/*
 * Copyright (c) 1996, 2013, Oracle and/or its affiliates. All rights reserved.
 * ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 *
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 */

package java.io;

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. 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
 * '&#92;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 {

 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}
 *
 * @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");
 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 <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 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.
 *
 * @exception 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
 *
 * @exception 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
 *
 * @exception IOException If an I/O error occurs
 */
 public void write(String str, int off, int len) throws IOException {
 se.write(str, off, len);
 }

 /**
 * Flushes the stream.
 *
 * @exception IOException If an I/O error occurs
 */
 public void flush() throws IOException {
 se.flush();
 }

 public void close() throws IOException {
 se.close();
 }
}