/*
* Copyright 2009 Martin Grotzke
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*
*/
package de.javakaffee.web.msm.serializer.javolution;
import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.util.Map;
import javolution.xml.XMLObjectReader;
import javolution.xml.XMLObjectWriter;
import javolution.xml.XMLReferenceResolver;
import javolution.xml.stream.XMLStreamException;
import org.apache.catalina.Loader;
import org.apache.catalina.Manager;
import org.apache.juli.logging.Log;
import org.apache.juli.logging.LogFactory;
import de.javakaffee.web.msm.MemcachedBackupSession;
import de.javakaffee.web.msm.SessionAttributesTranscoder;
import de.javakaffee.web.msm.TranscoderDeserializationException;
/**
* A {@link net.spy.memcached.transcoders.Transcoder} that serializes catalina
* {@link org.apache.catalina.session.StandardSession}s using <a
* href="http://javolution.org/">Javolutions</a> <a href="http://javolution.org/target/site/apidocs/javolution/xml/package-summary.html#package_description"
* > xml data binding</a> facilities.
* <p>
* Objects are serialized to/from xml using javolutions built in
* {@link javolution.xml.XMLFormat}s for standard types, custom/user types are bound using the
* {@link ReflectionFormat}.
* </p>
* <p>
* Additionally it's worth to note that cyclic dependencies are supported.
* </p>
*
* @author <a href="mailto:martin.grotzke@javakaffee.de">Martin Grotzke</a>
*/
public class JavolutionTranscoder implements SessionAttributesTranscoder {
static final String REFERENCE_ATTRIBUTE_ID = "__id";
static final String REFERENCE_ATTRIBUTE_REF_ID = "__ref";
private static final Log LOG = LogFactory.getLog( JavolutionTranscoder.class );
private final Manager _manager;
private final ReflectionBinding _xmlBinding;
/**
* Constructor.
*
* @param manager
* the manager
*/
public JavolutionTranscoder( final Manager manager ) {
this( manager, false );
}
/**
* Constructor.
*
* @param manager
* the manager
* @param copyCollectionsForSerialization
* specifies, if iterating over collection elements shall be done
* on a copy of the collection or on the collection itself
* @param customFormats a list of {@link CustomXMLFormat}s or <code>null</code>.
*/
public JavolutionTranscoder( final Manager manager, final boolean copyCollectionsForSerialization,
final CustomXMLFormat<?> ... customFormats ) {
_manager = manager;
final Loader loader = _manager.getContainer().getLoader();
_xmlBinding = new ReflectionBinding( loader.getClassLoader(), copyCollectionsForSerialization, customFormats );
}
/**
* Constructor.
*
* @param classLoader
* the classLoader
* @param copyCollectionsForSerialization
* specifies, if iterating over collection elements shall be done
* on a copy of the collection or on the collection itself
* @param customFormats a list of {@link CustomXMLFormat}s or <code>null</code>.
*/
public JavolutionTranscoder( final ClassLoader classLoader, final boolean copyCollectionsForSerialization,
final CustomXMLFormat<?> ... customFormats ) {
_manager = null;
_xmlBinding = new ReflectionBinding( classLoader, copyCollectionsForSerialization, customFormats );
}
/**
* {@inheritDoc}
*/
@Override
public byte[] serializeAttributes( final MemcachedBackupSession session, final Map<String, Object> attributes ) {
return doSerialize( attributes, "attributes" );
}
private byte[] doSerialize( final Object object, final String name ) {
if ( object == null ) {
throw new NullPointerException( "Can't serialize null" );
}
XMLObjectWriter writer = null;
try {
final ByteArrayOutputStream bos = new ByteArrayOutputStream();
writer = XMLObjectWriter.newInstance( bos );
final XMLReferenceResolver xmlReferenceResolver = new XMLReferenceResolver();
xmlReferenceResolver.setIdentifierAttribute( REFERENCE_ATTRIBUTE_ID );
xmlReferenceResolver.setReferenceAttribute( REFERENCE_ATTRIBUTE_REF_ID );
writer.setReferenceResolver( xmlReferenceResolver );
writer.setBinding( _xmlBinding );
writer.write( object, name );
writer.flush();
if ( LOG.isDebugEnabled() ) {
LOG.debug( "Returning serialized data:\n" + new String( bos.toByteArray() ) );
}
return bos.toByteArray();
} catch ( final Exception e ) {
LOG.error( "caught exception", e );
throw new IllegalArgumentException( "Could not serialize object", e );
} finally {
closeSilently( writer );
}
}
/**
* Get the object represented by the given serialized bytes.
*
* @param in
* the bytes to deserialize
* @return the resulting object
*/
@Override
public Map<String, Object> deserializeAttributes( final byte[] in ) {
if ( LOG.isDebugEnabled() ) {
LOG.debug( "Reading serialized data:\n" + new String( in ) );
}
return doDeserialize( in, "attributes" );
}
private <T> T doDeserialize( final byte[] in, final String name ) {
// getLogger().info( "Loading serialized:\n" + new String( in ) );
XMLObjectReader reader = null;
try {
final ByteArrayInputStream bis = new ByteArrayInputStream( in );
reader = XMLObjectReader.newInstance( bis );
final XMLReferenceResolver xmlReferenceResolver = new XMLReferenceResolver();
xmlReferenceResolver.setIdentifierAttribute( REFERENCE_ATTRIBUTE_ID );
xmlReferenceResolver.setReferenceAttribute( REFERENCE_ATTRIBUTE_REF_ID );
reader.setReferenceResolver( xmlReferenceResolver );
reader.setBinding( _xmlBinding );
if ( !reader.hasNext() ) {
throw new IllegalStateException( "reader has no input" );
}
return reader.<T> read( name );
} catch ( final RuntimeException e ) {
LOG.warn( "Caught Exception decoding "+ in.length +" bytes of data", e );
throw new TranscoderDeserializationException(e);
} catch ( final XMLStreamException e ) {
LOG.warn( "Caught Exception decoding "+ in.length +" bytes of data", e );
throw new TranscoderDeserializationException( e );
} finally {
closeSilently( reader );
}
}
private void closeSilently( final XMLObjectWriter stream ) {
if ( stream != null ) {
try {
stream.close();
} catch ( final XMLStreamException e ) {
// fail silently
}
}
}
private void closeSilently( final XMLObjectReader stream ) {
if ( stream != null ) {
try {
stream.close();
} catch ( final XMLStreamException e ) {
// fail silently
}
}
}
}