jdk/src/share/classes/java/io/OutputStreamWriter.java
changeset 2 90ce3da70b43
child 5506 202f599c92aa
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/jdk/src/share/classes/java/io/OutputStreamWriter.java	Sat Dec 01 00:00:00 2007 +0000
@@ -0,0 +1,235 @@
+/*
+ * Copyright 1996-2006 Sun Microsystems, Inc.  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.  Sun designates this
+ * particular file as subject to the "Classpath" exception as provided
+ * by Sun 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
+ * CA 95054 USA or visit www.sun.com if you need additional information or
+ * have any questions.
+ */
+
+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 <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
+ * '&#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 </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");
+        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. </p>
+     *
+     * @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.  </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 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();
+    }
+}