// Copyright (c) 2003-2012, Jodd Team (jodd.org). All Rights Reserved.
package jodd.servlet.filter;
import java.io.IOException;
import java.util.zip.GZIPOutputStream;
import javax.servlet.ServletOutputStream;
import javax.servlet.http.HttpServletResponse;
public class GzipResponseStream extends ServletOutputStream {
/**
* Construct a servlet output stream associated with the specified Response.
*
* @param response The associated response
*
* @exception IOException
*/
public GzipResponseStream(HttpServletResponse response) throws IOException {
super();
closed = false;
this.response = response;
this.output = response.getOutputStream();
}
/**
* The threshold number which decides to compress or not.
*/
protected int compressionThreshold;
/**
* The buffer through which all of our output bytes are passed.
*/
protected byte[] buffer;
/**
* The number of data bytes currently in the buffer.
*/
protected int bufferCount;
/**
* The underlying gzip output stream to which we should write data.
*/
protected GZIPOutputStream gzipstream;
/**
* Has this stream been closed?
*/
protected boolean closed;
/**
* The content length past which we will not write, or -1 if there is no
* defined content length.
*/
protected int length = -1;
/**
* The response with which this servlet output stream is associated.
*/
protected HttpServletResponse response;
/**
* The underlying servlet output stream to which we should write data.
*/
protected ServletOutputStream output;
/**
* Set the compressionThreshold number and create buffer for this size
*/
protected void setBuffer(int threshold) {
compressionThreshold = threshold;
buffer = new byte[compressionThreshold];
}
/**
* Close this output stream, causing any buffered data to be flushed and any
* further output data to throw an IOException.
*
* @exception IOException
*/
@Override
public void close() throws IOException {
if (closed == true) {
return;
}
if (gzipstream != null) {
flushToGZip();
gzipstream.close();
gzipstream = null;
} else {
if (bufferCount > 0) {
output.write(buffer, 0, bufferCount);
bufferCount = 0;
}
}
output.close();
closed = true;
}
/**
* Flush any buffered data for this output stream, which also causes the
* response to be committed.
*
* @exception IOException
*/
@Override
public void flush() throws IOException {
if (closed) {
return;
}
if (gzipstream != null) {
gzipstream.flush();
}
}
public void flushToGZip() throws IOException {
if (bufferCount > 0) {
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
*/
@Override
public void write(int b) throws IOException {
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 byte array to be written
*
* @exception IOException
* if an input/output error occurs
*/
@Override
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 byte array containing the bytes to be written
* @param off zero-relative starting offset of the bytes to be written
* @param len number of bytes to be written
*
* @exception IOException
* if an input/output error occurs
*/
@Override
public void write(byte b[], int off, int len) throws IOException {
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);
}
public void writeToGZip(byte b[], int off, int len) throws IOException {
if (gzipstream == null) {
gzipstream = new GZIPOutputStream(output);
response.addHeader("Content-Encoding", "gzip");
}
gzipstream.write(b, off, len);
}
/**
* Has this response stream been closed?
*
* @return true if stream has been closed
*/
public boolean closed() {
return(this.closed);
}
}
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