/*
* This code is from "Servlets and JavaServer pages; the J2EE Web Tier",
* http://www.jspbook.com. You may freely use the code both commercially
* and non-commercially. If you like the code, please pick up a copy of
* the book and help support the authors, development of more free code,
* and the JSP/Servlet/J2EE community.
*/
package com.cv.servlet.filter.compression;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.util.zip.GZIPOutputStream;
import javax.servlet.ServletOutputStream;
import javax.servlet.http.HttpServletResponse;
import org.apache.log4j.Logger;
public class GZIPResponseStream extends ServletOutputStream {
private static final Logger LOGGER = Logger.getLogger(GZIPResponseStream.class);
protected ByteArrayOutputStream baos = null;
protected GZIPOutputStream gzipstream = null;
protected boolean closed = false;
protected HttpServletResponse response = null;
protected ServletOutputStream output = null;
public GZIPResponseStream(HttpServletResponse response) throws IOException {
super();
closed = false;
this.response = response;
this.output = response.getOutputStream();
baos = new ByteArrayOutputStream();
gzipstream = new GZIPOutputStream(baos);
}
public void close() throws IOException {
if (closed) {
LOGGER.error(
"LOGGER : This output stream has already been closed" );
throw new IOException("This output stream has already been closed");
}
gzipstream.finish();
byte[] bytes = baos.toByteArray();
response.addHeader("Content-Length", Integer.toString(bytes.length));
response.addHeader("Content-Encoding", "gzip");
output.write(bytes);
output.flush();
output.close();
closed = true;
}
public void flush() throws IOException {
if (closed) {
LOGGER.error(
"LOGGER : Cannot flush a closed output stream" );
throw new IOException("Cannot flush a closed output stream");
}
gzipstream.flush();
}
public void write(int b) throws IOException {
if (closed) {
LOGGER.error(
"LOGGER : Cannot write to a closed output stream" );
throw new IOException("Cannot write to a closed output stream");
}
gzipstream.write((byte) b);
}
public void write(byte b[]) throws IOException {
write(b, 0, b.length);
}
public void write(byte b[], int off, int len) throws IOException {
if (closed) {
LOGGER.error(
"LOGGER : Cannot write to a closed output stream" );
throw new IOException("Cannot write to a closed output stream");
}
gzipstream.write(b, off, len);
}
public boolean closed() {
return (this.closed);
}
public void reset() {
}
} | 
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