📄 compressionresponsestream.java
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/*
* CompressionResponseStream.java
* $Header: /home/cvs/jakarta-tomcat-4.0/webapps/examples/WEB-INF/classes/compressionFilters/CompressionResponseStream.java,v 1.7 2003/09/13 14:28:46 funkman Exp $
* $Revision: 1.7 $
* $Date: 2003/09/13 14:28:46 $
*
* ====================================================================
*
* The Apache Software License, Version 1.1
*
* Copyright (c) 1999 The Apache Software Foundation. All rights
* reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* 2. 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.
*
* 3. The end-user documentation included with the redistribution, if
* any, must include the following acknowlegement:
* "This product includes software developed by the
* Apache Software Foundation (http://www.apache.org/)."
* Alternately, this acknowlegement may appear in the software itself,
* if and wherever such third-party acknowlegements normally appear.
*
* 4. The names "The Jakarta Project", "Tomcat", and "Apache Software
* Foundation" must not be used to endorse or promote products derived
* from this software without prior written permission. For written
* permission, please contact apache@apache.org.
*
* 5. Products derived from this software may not be called "Apache"
* nor may "Apache" appear in their names without prior written
* permission of the Apache Group.
*
* THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED 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 APACHE SOFTWARE FOUNDATION OR
* ITS 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.
* ====================================================================
*
* 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/>.
*
* [Additional notices, if required by prior licensing conditions]
*
*/
package jaoso.framework.web.filter.compression;
import java.io.IOException;
import java.util.zip.GZIPOutputStream;
import javax.servlet.ServletOutputStream;
import javax.servlet.http.HttpServletResponse;
/**
* Implementation of <b>ServletOutputStream</b> that works with
* the CompressionServletResponseWrapper implementation.
*
* @author Amy Roh
* @author Dmitri Valdin
* @version $Revision: 1.7 $, $Date: 2003/09/13 14:28:46 $
*/
public class CompressionResponseStream extends ServletOutputStream {
//~ Instance fields ========================================================
/**
* The underlying gzip output stream to which we should write data.
*/
protected GZIPOutputStream gzipstream = null;
/**
* The response with which this servlet output stream is associated.
*/
protected HttpServletResponse response = null;
/**
* The underlying servket output stream to which we should write data.
*/
protected ServletOutputStream output = null;
/**
* The buffer through which all of our output bytes are passed.
*/
protected byte[] buffer = null;
/**
* Has this stream been closed?
*/
protected boolean closed = false;
/**
* The number of data bytes currently in the buffer.
*/
protected int bufferCount = 0;
// ----------------------------------------------------- Instance Variables
/**
* The threshold number which decides to compress or not.
* Users can configure in web.xml to set it to fit their needs.
*/
protected int compressionThreshold = 0;
/**
* The content length past which we will not write, or -1 if there is
* no defined content length.
*/
protected int length = -1;
/**
* Debug level
*/
private int debug = 0;
//~ Constructors ===========================================================
// ----------------------------------------------------------- Constructors
/**
* Construct a servlet output stream associated with the specified Response.
*
* @param response The associated response
*/
public CompressionResponseStream(HttpServletResponse response)
throws IOException {
super();
closed = false;
this.response = response;
this.output = response.getOutputStream();
}
//~ Methods ================================================================
// --------------------------------------------------------- Public Methods
/**
* Set debug level
*/
public void setDebugLevel(int debug) {
this.debug = debug;
}
/**
* Close this output stream, causing any buffered data to be flushed and
* any further output data to throw an IOException.
*/
public void close() throws IOException {
if (debug > 1) {
System.out.println("close() @ CompressionResponseStream");
}
if (closed) {
throw new IOException("This output stream has already been closed");
}
if (gzipstream != null) {
flushToGZip();
gzipstream.close();
gzipstream = null;
} else {
if (bufferCount > 0) {
if (debug > 2) {
System.out.print("output.write(");
System.out.write(buffer, 0, bufferCount);
System.out.println(")");
}
output.write(buffer, 0, bufferCount);
bufferCount = 0;
}
}
output.close();
closed = true;
}
// -------------------------------------------------------- Package Methods
/**
* Has this response stream been closed?
*/
public boolean closed() {
return (this.closed);
}
/**
* Flush any buffered data for this output stream, which also causes the
* response to be committed.
*/
public void flush() throws IOException {
if (debug > 1) {
System.out.println("flush() @ CompressionResponseStream");
}
if (closed) {
throw new IOException("Cannot flush a closed output stream");
}
if (gzipstream != null) {
gzipstream.flush();
}
}
/**
* DOCUMENT ME!
*
* @throws IOException DOCUMENT ME!
*/
public void flushToGZip() throws IOException {
if (debug > 1) {
System.out.println("flushToGZip() @ CompressionResponseStream");
}
if (bufferCount > 0) {
if (debug > 1) {
System.out.println("flushing out to GZipStream, bufferCount = "
+ bufferCount);
}
writeToGZip(buffer, 0, bufferCount);
bufferCount = 0;
}
}
/**
* Write the specified byte to our output stream.
*
* @param b The byte to be written
*
* @exception IOException if an input/output error occurs
*/
public void write(int b) throws IOException {
if (debug > 1) {
System.out.println("write " + b + " in CompressionResponseStream ");
}
if (closed) {
throw new IOException("Cannot write to a closed output stream");
}
if (bufferCount >= buffer.length) {
flushToGZip();
}
buffer[bufferCount++] = (byte) b;
}
/**
* Write <code>b.length</code> bytes from the specified byte array
* to our output stream.
*
* @param b The byte array to be written
*
* @exception IOException if an input/output error occurs
*/
public void write(byte[] b) throws IOException {
write(b, 0, b.length);
}
/**
* Write <code>len</code> bytes from the specified byte array, starting
* at the specified offset, to our output stream.
*
* @param b The byte array containing the bytes to be written
* @param off Zero-relative starting offset of the bytes to be written
* @param len The number of bytes to be written
*
* @exception IOException if an input/output error occurs
*/
public void write(byte[] b, int off, int len) throws IOException {
if (debug > 1) {
System.out.println("write, bufferCount = " + bufferCount
+ " len = " + len + " off = " + off);
}
if (debug > 2) {
System.out.print("write(");
System.out.write(b, off, len);
System.out.println(")");
}
if (closed) {
throw new IOException("Cannot write to a closed output stream");
}
if (len == 0) {
return;
}
// Can we write into buffer ?
if (len <= (buffer.length - bufferCount)) {
System.arraycopy(b, off, buffer, bufferCount, len);
bufferCount += len;
return;
}
// There is not enough space in buffer. Flush it ...
flushToGZip();
// ... and try again. Note, that bufferCount = 0 here !
if (len <= (buffer.length - bufferCount)) {
System.arraycopy(b, off, buffer, bufferCount, len);
bufferCount += len;
return;
}
// write direct to gzip
writeToGZip(b, off, len);
}
/**
* DOCUMENT ME!
*
* @param b DOCUMENT ME!
* @param off DOCUMENT ME!
* @param len DOCUMENT ME!
*
* @throws IOException DOCUMENT ME!
*/
public void writeToGZip(byte[] b, int off, int len)
throws IOException {
if (debug > 1) {
System.out.println("writeToGZip, len = " + len);
}
if (debug > 2) {
System.out.print("writeToGZip(");
System.out.write(b, off, len);
System.out.println(")");
}
if (gzipstream == null) {
if (debug > 1) {
System.out.println("new GZIPOutputStream");
}
response.addHeader("Content-Encoding", "gzip");
gzipstream = new GZIPOutputStream(output);
}
gzipstream.write(b, off, len);
}
/**
* Set the compressionThreshold number and create buffer for this size
*/
protected void setBuffer(int threshold) {
compressionThreshold = threshold;
buffer = new byte[compressionThreshold];
if (debug > 1) {
System.out.println("buffer is set to " + compressionThreshold);
}
}
}
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