/*
* $HeadURL: http://svn.apache.org/repos/asf/httpcomponents/httpcore/tags/4.0/module-main/src/main/java/org/apache/http/impl/io/AbstractSessionOutputBuffer.java $
* $Revision: 744526 $
* $Date: 2009-02-14 18:04:18 +0100 (Sat, 14 Feb 2009) $
*
* ====================================================================
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing,
* software distributed under the License is distributed on an
* "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
* KIND, either express or implied. See the License for the
* specific language governing permissions and limitations
* under the License.
* ====================================================================
*
* This software consists of voluntary contributions made by many
* individuals on behalf of the Apache Software Foundation. For more
* information on the Apache Software Foundation, please see
* <http://www.apache.org/>.
*
*/
package org.apache.http.impl.io;
import java.io.IOException;
import java.io.OutputStream;
import org.apache.http.io.SessionOutputBuffer;
import org.apache.http.io.HttpTransportMetrics;
import org.apache.http.params.CoreProtocolPNames;
import org.apache.http.params.HttpParams;
import org.apache.http.params.HttpProtocolParams;
import org.apache.http.protocol.HTTP;
import org.apache.http.util.ByteArrayBuffer;
import org.apache.http.util.CharArrayBuffer;
/**
* Abstract base class for session output buffers that stream data to
* an arbitrary {@link OutputStream}. This class buffers small chunks of
* output data in an internal byte array for optimal output performance.
* <p>
* {@link #writeLine(CharArrayBuffer)} and {@link #writeLine(String)} methods
* of this class use CR-LF as a line delimiter.
*
* @since 4.0
*/
public abstract class AbstractSessionOutputBuffer implements SessionOutputBuffer {
private static final byte[] CRLF = new byte[] {HTTP.CR, HTTP.LF};
private static final int MAX_CHUNK = 256;
private OutputStream outstream;
private ByteArrayBuffer buffer;
private String charset = HTTP.US_ASCII;
private boolean ascii = true;
private HttpTransportMetricsImpl metrics;
/**
* Initializes this session output buffer.
* <p>
* The following HTTP parameters affect the initialization:
* <p>
* The {@link CoreProtocolPNames#HTTP_ELEMENT_CHARSET}
* parameter determines the charset to be used for encoding HTTP lines. If
* not specified, <code>US-ASCII</code> will be used per default.
*
* @param outstream the destination output stream.
* @param buffersize the size of the internal buffer.
* @param params HTTP parameters.
*
* @see CoreProtocolPNames#HTTP_ELEMENT_CHARSET
*/
protected void init(final OutputStream outstream, int buffersize, final HttpParams params) {
if (outstream == null) {
throw new IllegalArgumentException("Input stream may not be null");
}
if (buffersize <= 0) {
throw new IllegalArgumentException("Buffer size may not be negative or zero");
}
if (params == null) {
throw new IllegalArgumentException("HTTP parameters may not be null");
}
this.outstream = outstream;
this.buffer = new ByteArrayBuffer(buffersize);
this.charset = HttpProtocolParams.getHttpElementCharset(params);
this.ascii = this.charset.equalsIgnoreCase(HTTP.US_ASCII)
|| this.charset.equalsIgnoreCase(HTTP.ASCII);
this.metrics = new HttpTransportMetricsImpl();
}
protected void flushBuffer() throws IOException {
int len = this.buffer.length();
if (len > 0) {
this.outstream.write(this.buffer.buffer(), 0, len);
this.buffer.clear();
this.metrics.incrementBytesTransferred(len);
}
}
public void flush() throws IOException {
flushBuffer();
this.outstream.flush();
}
public void write(final byte[] b, int off, int len) throws IOException {
if (b == null) {
return;
}
// Do not want to buffer largish chunks
// if the byte array is larger then MAX_CHUNK
// write it directly to the output stream
if (len > MAX_CHUNK || len > this.buffer.capacity()) {
// flush the buffer
flushBuffer();
// write directly to the out stream
this.outstream.write(b, off, len);
this.metrics.incrementBytesTransferred(len);
} else {
// Do not let the buffer grow unnecessarily
int freecapacity = this.buffer.capacity() - this.buffer.length();
if (len > freecapacity) {
// flush the buffer
flushBuffer();
}
// buffer
this.buffer.append(b, off, len);
}
}
public void write(final byte[] b) throws IOException {
if (b == null) {
return;
}
write(b, 0, b.length);
}
public void write(int b) throws IOException {
if (this.buffer.isFull()) {
flushBuffer();
}
this.buffer.append(b);
}
/**
* Writes characters from the specified string followed by a line delimiter
* to this session buffer.
* <p>
* This method uses CR-LF as a line delimiter.
*
* @param s the line.
* @exception IOException if an I/O error occurs.
*/
public void writeLine(final String s) throws IOException {
if (s == null) {
return;
}
if (s.length() > 0) {
write(s.getBytes(this.charset));
}
write(CRLF);
}
/**
* Writes characters from the specified char array followed by a line
* delimiter to this session buffer.
* <p>
* This method uses CR-LF as a line delimiter.
*
* @param s the buffer containing chars of the line.
* @exception IOException if an I/O error occurs.
*/
public void writeLine(final CharArrayBuffer s) throws IOException {
if (s == null) {
return;
}
if (this.ascii) {
int off = 0;
int remaining = s.length();
while (remaining > 0) {
int chunk = this.buffer.capacity() - this.buffer.length();
chunk = Math.min(chunk, remaining);
if (chunk > 0) {
this.buffer.append(s, off, chunk);
}
if (this.buffer.isFull()) {
flushBuffer();
}
off += chunk;
remaining -= chunk;
}
} else {
// This is VERY memory inefficient, BUT since non-ASCII charsets are
// NOT meant to be used anyway, there's no point optimizing it
byte[] tmp = s.toString().getBytes(this.charset);
write(tmp);
}
write(CRLF);
}
public HttpTransportMetrics getMetrics() {
return this.metrics;
}
}