WriterOutputStream.java
/*
* Copyright (c) 2008, Harald Kuhr
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* * Redistributions of source code must retain the above copyright notice, this
* list of conditions and the following disclaimer.
*
* * Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
*
* * Neither the name of the copyright holder nor the names of its
* contributors may be used to endorse or promote products derived from
* this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
* CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
package com.twelvemonkeys.io;
import com.twelvemonkeys.lang.DateUtil;
import java.io.*;
import java.nio.ByteBuffer;
import java.nio.CharBuffer;
import java.nio.charset.Charset;
/**
* Wraps a {@code Writer} in an {@code OutputStream}.
* <p>
* <em>Instances of this class are not thread-safe.</em>
* </p>
* <p>
* <em>NOTE: This class is probably not the right way of solving your problem,
* however it might prove useful in JSPs etc.
* If possible, it's always better to use the {@code Writer}'s underlying
* {@code OutputStream}, or wrap it's native backing.
* </em>
* </p>
*
* @author <a href="mailto:harald.kuhr@gmail.com">Harald Kuhr</a>
* @version $Id: //depot/branches/personal/haraldk/twelvemonkeys/release-2/twelvemonkeys-core/src/main/java/com/twelvemonkeys/io/WriterOutputStream.java#2 $
*/
public class WriterOutputStream extends OutputStream {
protected Writer writer;
final protected Decoder decoder;
final ByteArrayOutputStream bufferStream = new FastByteArrayOutputStream(1024);
private volatile boolean isFlushing = false; // Ugly but critical...
private static final boolean NIO_AVAILABLE = isNIOAvailable();
private static boolean isNIOAvailable() {
try {
Class.forName("java.nio.charset.Charset");
return true;
}
catch (Throwable t) {
// Ignore
}
return false;
}
public WriterOutputStream(final Writer pWriter, final String pCharset) {
writer = pWriter;
decoder = getDecoder(pCharset);
}
public WriterOutputStream(final Writer pWriter) {
this(pWriter, null);
}
private static Decoder getDecoder(final String pCharset) {
// NOTE: The CharsetDecoder is typically 10-20% faster than
// StringDecoder according to my tests
// StringEncoder is horribly slow on 1.2 systems, but there's no
// alternative...
if (NIO_AVAILABLE) {
return new CharsetDecoder(pCharset);
}
return new StringDecoder(pCharset);
}
@Override
public void close() throws IOException {
flush();
writer.close();
writer = null;
}
@Override
public void flush() throws IOException {
flushBuffer();
writer.flush();
}
@Override
public final void write(byte[] pBytes) throws IOException {
if (pBytes == null) {
throw new NullPointerException("bytes == null");
}
write(pBytes, 0, pBytes.length);
}
@Override
public final void write(byte[] pBytes, int pOffset, int pLength) throws IOException {
flushBuffer();
decoder.decodeTo(writer, pBytes, pOffset, pLength);
}
@Override
public final void write(int pByte) {
// TODO: Is it possible to know if this is a good place in the stream to
// flush? It might be in the middle of a multi-byte encoded character..
bufferStream.write(pByte);
}
private void flushBuffer() throws IOException {
if (!isFlushing && bufferStream.size() > 0) {
isFlushing = true;
bufferStream.writeTo(this); // NOTE: Avoids cloning buffer array
bufferStream.reset();
isFlushing = false;
}
}
///////////////////////////////////////////////////////////////////////////
public static void main(String[] pArgs) throws IOException {
int iterations = 1000000;
byte[] bytes = "������������������ klashf lkash ljah lhaaklhghdfgu ksd".getBytes("UTF-8");
Decoder d;
long start;
long time;
Writer sink = new PrintWriter(new NullOutputStream());
StringWriter writer;
String str;
d = new StringDecoder("UTF-8");
for (int i = 0; i < 10000; i++) {
d.decodeTo(sink, bytes, 0, bytes.length);
}
start = System.currentTimeMillis();
for (int i = 0; i < iterations; i++) {
d.decodeTo(sink, bytes, 0, bytes.length);
}
time = DateUtil.delta(start);
System.out.println("StringDecoder");
System.out.println("time: " + time);
writer = new StringWriter();
d.decodeTo(writer, bytes, 0, bytes.length);
str = writer.toString();
System.out.println("str: \"" + str + "\"");
System.out.println("chars.length: " + str.length());
System.out.println();
if (NIO_AVAILABLE) {
d = new CharsetDecoder("UTF-8");
for (int i = 0; i < 10000; i++) {
d.decodeTo(sink, bytes, 0, bytes.length);
}
start = System.currentTimeMillis();
for (int i = 0; i < iterations; i++) {
d.decodeTo(sink, bytes, 0, bytes.length);
}
time = DateUtil.delta(start);
System.out.println("CharsetDecoder");
System.out.println("time: " + time);
writer = new StringWriter();
d.decodeTo(writer, bytes, 0, bytes.length);
str = writer.toString();
System.out.println("str: \"" + str + "\"");
System.out.println("chars.length: " + str.length());
System.out.println();
}
OutputStream os = new WriterOutputStream(new PrintWriter(System.out), "UTF-8");
os.write(bytes);
os.flush();
System.out.println();
for (byte b : bytes) {
os.write(b & 0xff);
}
os.flush();
}
///////////////////////////////////////////////////////////////////////////
private static interface Decoder {
void decodeTo(Writer pWriter, byte[] pBytes, int pOffset, int pLength) throws IOException;
}
private static final class CharsetDecoder implements Decoder {
final Charset mCharset;
CharsetDecoder(String pCharset) {
// Handle null-case, to get default charset
String charset = pCharset != null ? pCharset :
System.getProperty("file.encoding", "ISO-8859-1");
mCharset = Charset.forName(charset);
}
public void decodeTo(Writer pWriter, byte[] pBytes, int pOffset, int pLength) throws IOException {
CharBuffer cb = mCharset.decode(ByteBuffer.wrap(pBytes, pOffset, pLength));
pWriter.write(cb.array(), 0, cb.length());
}
}
private static final class StringDecoder implements Decoder {
final String mCharset;
StringDecoder(String pCharset) {
mCharset = pCharset;
}
public void decodeTo(Writer pWriter, byte[] pBytes, int pOffset, int pLength) throws IOException {
String str = mCharset == null ?
new String(pBytes, pOffset, pLength) :
new String(pBytes, pOffset, pLength, mCharset);
pWriter.write(str);
}
}
}