/*
* JBoss, Home of Professional Open Source
* Copyright 2005, JBoss Inc., and individual contributors as indicated
* by the @authors tag. See the copyright.txt in the distribution for a
* full listing of individual contributors.
*
* This is free software; you can redistribute it and/or modify it
* under the terms of the GNU Lesser General Public License as
* published by the Free Software Foundation; either version 2.1 of
* the License, or (at your option) any later version.
*
* This software is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this software; if not, write to the Free
* Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
* 02110-1301 USA, or see the FSF site: http://www.fsf.org.
*/
package org.jboss.remoting.marshal.compress;
import java.io.BufferedOutputStream;
import java.io.IOException;
import java.io.ObjectOutputStream;
import java.io.OutputStream;
import java.util.zip.Deflater;
import java.util.zip.GZIPOutputStream;
import org.jboss.remoting.marshal.Marshaller;
import org.jboss.remoting.marshal.VersionedMarshaller;
import org.jboss.remoting.marshal.serializable.SerializableMarshaller;
import org.jboss.remoting.serialization.SerializationStreamFactory;
/**
* <code>CompressingMarshaller</code> and <code>CompressingUnMarshaller</code> are a general
* purpose compressing marshaller / decompressing unmarshaller pair based on Java's GZIP facilities.
* <p/>
* <code>CompressingMarshaller</code> is subclassed from <code>SerializableMarshaller</code>, and by default
* it uses <code>super.write()</code> to marshall an object, which is then
* compressed. Optionally, it can wrap any other marshaller and use that instead of
* <code>SerializableMarshaller</code> to marshall an object before it is compressed. For example,
* <p/>
* <center><code>new CompressingMarshaller(new HTTPMarshaller())</code></center>
* <p/>
* will create a marshaller that compresses the output of an <code>HTTPMarshaller</code>.
*
* @author <a href="mailto:r.sigal@computer.org">Ron Sigal</a>
* @version $Revision: 5337 $
* <p/>
* Copyright (c) 2005
* </p>
*/
public class CompressingMarshaller extends SerializableMarshaller
{
public final static String DATATYPE = "compressible";
private Marshaller wrappedMarshaller;
private static final long serialVersionUID = 8731343309128430753L;
/**
* Create a new CompressingMarshaller.
*/
public CompressingMarshaller()
{
}
/**
* Create a new CompressingMarshaller.
*
* @param marshaller A <code>Marshaller</code> which is used to turn objects into byte streams.
*/
public CompressingMarshaller(Marshaller marshaller)
{
wrappedMarshaller = marshaller;
}
public OutputStream getMarshallingStream(OutputStream outputStream) throws IOException
{
GZIPOutputStream gzos = new SelfCleaningGZipOutputStream(outputStream);
DecomposableBufferedOutputStream bos = new DecomposableBufferedOutputStream(gzos);
return bos;
}
/**
* Writes compressed, marshalled form of <code>dataObject</code> to <code>output</code>.
*
* @param dataObject arbitrary object to be marshalled
* @param output <code>OutputStream</code> to which <code>output</code> is to be marshalled
* @param version wire format version
*/
public void write(Object dataObject, OutputStream output, int version) throws IOException
{
SelfCleaningGZipOutputStream gzos = null;
DecomposableBufferedOutputStream bos = null;
if (output instanceof DecomposableBufferedOutputStream)
{
bos = (DecomposableBufferedOutputStream) output;
gzos = (SelfCleaningGZipOutputStream) bos.getWrappedStream();
gzos.refreshDeflater();
}
else
{
gzos = new SelfCleaningGZipOutputStream(output);
bos = new DecomposableBufferedOutputStream(gzos);
}
ObjectOutputStream oos = SerializationStreamFactory.getManagerInstance(getSerializationType()).createOutput(bos);
if(wrappedMarshaller != null)
{
if (wrappedMarshaller instanceof VersionedMarshaller)
((VersionedMarshaller) wrappedMarshaller).write(dataObject, oos, version);
else
wrappedMarshaller.write(dataObject, oos);
}
else
{
super.write(dataObject, oos, version);
}
oos.flush();
bos.flush();
gzos.finish();
gzos.flush();
}
/**
* Returns a <code>CompressingMarshaller</code>.
*
* @return a <code>CompressingMarshaller</code>.
* @throws CloneNotSupportedException In practice no exceptions are thrown
*/
public Marshaller cloneMarshaller() throws CloneNotSupportedException
{
return new CompressingMarshaller(wrappedMarshaller);
}
/**
* @author Doychin Bondzhev
*/
static class SelfCleaningGZipOutputStream extends GZIPOutputStream
{
boolean used;
public SelfCleaningGZipOutputStream(OutputStream out) throws IOException
{
super(out);
}
void refreshDeflater()
{
if (used)
{
def = new Deflater(Deflater.DEFAULT_COMPRESSION, true);
crc.reset();
}
else
{
used = true;
}
}
/**
* Writes remaining compressed data to the output stream and closes the underlying stream.
* @exception IOException if an I/O error has occurred
*/
public void finish() throws IOException
{
super.finish();
def.end(); // This will release all resources used by zlib native code
}
}
static class DecomposableBufferedOutputStream extends BufferedOutputStream
{
DecomposableBufferedOutputStream(OutputStream out, int size)
{
super(out, size);
}
DecomposableBufferedOutputStream(OutputStream out)
{
super(out);
}
OutputStream getWrappedStream()
{
return out;
}
}
}