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/*
 * Copyright 2010 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 static de.javakaffee.web.msm.serializer.javolution.ReflectionBinding.XMLJdkProxyFormat.getInterfaceNames;
import static de.javakaffee.web.msm.serializer.javolution.ReflectionBinding.XMLJdkProxyFormat.getInterfaces;
import javolution.xml.stream.XMLStreamException;
import net.sf.cglib.proxy.Callback;
import net.sf.cglib.proxy.Enhancer;
import net.sf.cglib.proxy.Factory;

/**
 * A format that serializes/deserializes cglib proxies.
 * 
 * @author Martin Grotzke
 */
public class CGLibProxyFormat extends CustomXMLFormat {

    private static String DEFAULT_NAMING_MARKER = "$$EnhancerByCGLIB$$";
    
    private static final String CALLBACKS = "callbacks";
    private static final String INTERFACES = "interfaces";
    private static final String SUPERCLASS = "superclass";
   
    /**
     * {@inheritDoc}
     */
    @Override
    public boolean canConvert( final Class cls ) {
        return canSerialize( cls ) || canDeserialize( cls );
    }

    private boolean canDeserialize( final Class cls ) {
        return cls == CGLibProxyMarker.class;
    }

    private boolean canSerialize( final Class cls ) {
        return Enhancer.isEnhanced( cls ) && cls.getName().indexOf( DEFAULT_NAMING_MARKER ) > 0;
    }
    
    /**
     * This class is used as a marker class - written to the class attribute
     * on serialization and checked on deserialization (via {@link CGLibProxyFormat#canConvert(Class)}.
     */
    public static interface CGLibProxyMarker {}
    
    /**
     * Used to determine the class that is used for writing the class
     * attribute to the serialized xml.
     * 

* This implementation returns a marker class so that we know on deserialization * that we should handle/deserialize the serialized xml. *

* * @param the proxy class * @return the marker class {@link CGLibProxyMarker}. * * @see #canConvert(Class) */ @Override public Class getTargetClass( final Class cls ) { return CGLibProxyMarker.class; } /** * {@inheritDoc} */ @Override public boolean isReferenceable() { return false; } /** * {@inheritDoc} */ @Override public Object newInstance( final Class cls, final InputElement xml ) throws XMLStreamException { final Class superclass; try { superclass = Class.forName( xml.getAttribute( SUPERCLASS ).toString() ); } catch ( final ClassNotFoundException e ) { throw new XMLStreamException( e ); } /* this class should be loaded from the webapp, therefore we have access to the correct class loader */ final ClassLoader classLoader = getClass().getClassLoader(); final Class[] interfaces = getInterfaces( xml, INTERFACES, classLoader ); final Callback[] callbacks = xml.get( CALLBACKS ); return createProxy( superclass, interfaces, callbacks ); } private Object createProxy( final Class targetClass, final Class[] interfaces, final Callback[] callbacks ) { final Enhancer e = new Enhancer(); e.setInterfaces( interfaces ); e.setSuperclass( targetClass ); e.setCallbacks( callbacks ); return e.create(); } /** * {@inheritDoc} */ @Override public void read( final InputElement arg0, final Object arg1 ) throws XMLStreamException { // nothing to do... } /** * {@inheritDoc} */ @Override public void write( final Object obj, final OutputElement xml ) throws XMLStreamException { final Class superclass = obj.getClass().getSuperclass(); xml.setAttribute( SUPERCLASS, superclass.getName() ); final String[] interfaceNames = getInterfaceNames( obj ); xml.add( interfaceNames, INTERFACES ); final Callback[] callbacks = ((Factory)obj).getCallbacks(); xml.add( callbacks, CALLBACKS ); } }