com.gemstone.org.jgroups.protocols.COMPRESS Maven / Gradle / Ivy
Go to download
Show more of this group Show more artifacts with this name
Show all versions of gemfire-jgroups Show documentation
Show all versions of gemfire-jgroups Show documentation
SnappyData store based off Pivotal GemFireXD
/** Notice of modification as required by the LGPL
* This file was modified by Gemstone Systems Inc. on
* $Date$
**/
package com.gemstone.org.jgroups.protocols;
import com.gemstone.org.jgroups.Event;
import com.gemstone.org.jgroups.Global;
import com.gemstone.org.jgroups.Header;
import com.gemstone.org.jgroups.Message;
import com.gemstone.org.jgroups.stack.Protocol;
import com.gemstone.org.jgroups.util.ExternalStrings;
import com.gemstone.org.jgroups.util.Streamable;
import java.io.*;
import java.util.Properties;
import java.util.zip.DataFormatException;
import java.util.zip.Deflater;
import java.util.zip.Inflater;
/**
* Compresses the payload of a message. Goal is to reduce the number of messages sent across the wire.
* Should ideally be layered somewhere above a fragmentation protocol (e.g. FRAG).
* @author Bela Ban
* @version $Id: COMPRESS.java,v 1.10 2005/11/03 11:42:59 belaban Exp $
*/
public class COMPRESS extends Protocol {
Deflater deflater=null;
Inflater inflater=null;
/** Values are from 0-9 (0=no compression, 9=best compression) */
int compression_level=Deflater.BEST_COMPRESSION; // this is 9
/** Minimal payload size of a message (in bytes) for compression to kick in */
long min_size=500;
final static String name="COMPRESS";
@Override // GemStoneAddition
public String getName() {
return name;
}
@Override // GemStoneAddition
public void init() throws Exception {
deflater=new Deflater(compression_level);
inflater=new Inflater();
}
@Override // GemStoneAddition
public void destroy() {
deflater.end();
deflater=null;
inflater.end();
inflater=null;
}
@Override // GemStoneAddition
public boolean setProperties(Properties props) {
String str;
super.setProperties(props);
str=props.getProperty("compression_level");
if(str != null) {
compression_level=Integer.parseInt(str);
props.remove("compression_level");
}
str=props.getProperty("min_size");
if(str != null) {
min_size=Long.parseLong(str);
props.remove("min_size");
}
if(props.size() > 0) {
log.error(ExternalStrings.COMPRESS_COMPRESSSETPROPERTIES_THE_FOLLOWING_PROPERTIES_ARE_NOT_RECOGNIZED__0, props);
return false;
}
return true;
}
/**
* If there is no header, we pass the message up. Otherwise we uncompress the payload to its original size.
* @param evt
*/
@Override // GemStoneAddition
public void up(Event evt) {
if(evt.getType() == Event.MSG) {
Message msg=(Message)evt.getArg();
CompressHeader hdr=(CompressHeader)msg.removeHeader(name);
if(hdr != null) {
byte[] compressed_payload=msg.getRawBuffer();
if(compressed_payload != null && compressed_payload.length > 0) {
int original_size=hdr.original_size;
byte[] uncompressed_payload=new byte[original_size];
inflater.reset();
inflater.setInput(compressed_payload, msg.getOffset(), msg.getLength());
try {
inflater.inflate(uncompressed_payload);
if(trace)
log.trace("uncompressed " + compressed_payload.length + " bytes to " +
original_size + " bytes");
msg.setBuffer(uncompressed_payload);
}
catch(DataFormatException e) {
if(log.isErrorEnabled()) log.error(ExternalStrings.COMPRESS_EXCEPTION_ON_UNCOMPRESSION__0, e);
}
}
}
}
passUp(evt);
}
/**
* We compress the payload if it is larger than min_size. In this case we add a header containing
* the original size before compression. Otherwise we add no header.
* Note that we compress either the entire buffer (if offset/length are not used), or a subset (if offset/length
* are used)
* @param evt
*/
@Override // GemStoneAddition
public void down(Event evt) {
if(evt.getType() == Event.MSG) {
Message msg=(Message)evt.getArg();
int length=msg.getLength(); // takes offset/length (if set) into account
if(length >= min_size) {
byte[] payload=msg.getRawBuffer(); // here we get the ref so we can avoid copying
byte[] compressed_payload=new byte[length];
deflater.reset();
deflater.setInput(payload, msg.getOffset(), length);
deflater.finish();
deflater.deflate(compressed_payload);
int compressed_size=deflater.getTotalOut();
byte[] new_payload=new byte[compressed_size];
System.arraycopy(compressed_payload, 0, new_payload, 0, compressed_size);
msg.setBuffer(new_payload);
msg.putHeader(name, new CompressHeader(length));
if(trace)
log.trace("compressed payload from " + length + " bytes to " + compressed_size + " bytes");
}
}
passDown(evt);
}
public static class CompressHeader extends Header implements Streamable {
int original_size=0;
public CompressHeader() {
super();
}
public CompressHeader(int s) {
original_size=s;
}
@Override // GemStoneAddition
public long size(short version) {
return Global.INT_SIZE;
}
public void writeExternal(ObjectOutput out) throws IOException {
out.writeInt(original_size);
}
public void readExternal(ObjectInput in) throws IOException, ClassNotFoundException {
original_size=in.readInt();
}
public void writeTo(DataOutputStream out) throws IOException {
out.writeInt(original_size);
}
public void readFrom(DataInputStream in) throws IOException, IllegalAccessException, InstantiationException {
original_size=in.readInt();
}
}
}