/*
* Hibernate, Relational Persistence for Idiomatic Java
*
* Copyright (c) 2008-2011, Red Hat Inc. or third-party contributors as
* indicated by the @author tags or express copyright attribution
* statements applied by the authors. All third-party contributions are
* distributed under license by Red Hat Inc.
*
* This copyrighted material is made available to anyone wishing to use, modify,
* copy, or redistribute it subject to the terms and conditions of the GNU
* Lesser General Public License, as published by the Free Software Foundation.
*
* This program 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 distribution; if not, write to:
* Free Software Foundation, Inc.
* 51 Franklin Street, Fifth Floor
* Boston, MA 02110-1301 USA
*/
package org.hibernate.bytecode.internal.javassist;
import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.DataInputStream;
import java.io.DataOutputStream;
import java.io.IOException;
import java.security.ProtectionDomain;
import javassist.ClassClassPath;
import javassist.ClassPool;
import javassist.bytecode.ClassFile;
import org.jboss.logging.Logger;
import org.hibernate.HibernateException;
import org.hibernate.bytecode.buildtime.spi.ClassFilter;
import org.hibernate.bytecode.spi.AbstractClassTransformerImpl;
import org.hibernate.internal.CoreMessageLogger;
/**
* Enhance the classes allowing them to implements InterceptFieldEnabled
* This interface is then used by Hibernate for some optimizations.
*
* @author Emmanuel Bernard
* @author Steve Ebersole
* @author Dustin Schultz
*/
public class JavassistClassTransformer extends AbstractClassTransformerImpl {
private static final CoreMessageLogger LOG = Logger.getMessageLogger(CoreMessageLogger.class,
JavassistClassTransformer.class.getName());
public JavassistClassTransformer(ClassFilter classFilter, org.hibernate.bytecode.buildtime.spi.FieldFilter fieldFilter) {
super( classFilter, fieldFilter );
}
@Override
protected byte[] doTransform(
ClassLoader loader,
String className,
Class classBeingRedefined,
ProtectionDomain protectionDomain,
byte[] classfileBuffer) {
ClassFile classfile;
try {
// WARNING: classfile only
classfile = new ClassFile( new DataInputStream( new ByteArrayInputStream( classfileBuffer ) ) );
}
catch (IOException e) {
LOG.unableToBuildEnhancementMetamodel( className );
return classfileBuffer;
}
// This is the same as ClassPool.getDefault() but ensures a new ClassPool per
ClassPool cp = new ClassPool();
cp.appendSystemPath();
cp.appendClassPath(new ClassClassPath(this.getClass()));
cp.appendClassPath(new ClassClassPath(classfile.getClass()));
try {
cp.makeClassIfNew(new ByteArrayInputStream(classfileBuffer));
} catch (IOException e) {
throw new RuntimeException(e.getMessage(), e);
}
FieldTransformer transformer = getFieldTransformer( classfile, cp );
if ( transformer != null ) {
LOG.debugf( "Enhancing %s", className );
DataOutputStream out = null;
try {
transformer.transform( classfile );
ByteArrayOutputStream byteStream = new ByteArrayOutputStream();
out = new DataOutputStream( byteStream );
classfile.write( out );
return byteStream.toByteArray();
}
catch (Exception e) {
LOG.unableToTransformClass( e.getMessage() );
throw new HibernateException( "Unable to transform class: " + e.getMessage() );
}
finally {
try {
if ( out != null ) out.close();
}
catch (IOException e) {
//swallow
}
}
}
return classfileBuffer;
}
protected FieldTransformer getFieldTransformer(final ClassFile classfile, final ClassPool classPool) {
if ( alreadyInstrumented( classfile ) ) {
return null;
}
return new FieldTransformer(
new FieldFilter() {
public boolean handleRead(String desc, String name) {
return fieldFilter.shouldInstrumentField( classfile.getName(), name );
}
public boolean handleWrite(String desc, String name) {
return fieldFilter.shouldInstrumentField( classfile.getName(), name );
}
public boolean handleReadAccess(String fieldOwnerClassName, String fieldName) {
return fieldFilter.shouldTransformFieldAccess( classfile.getName(), fieldOwnerClassName, fieldName );
}
public boolean handleWriteAccess(String fieldOwnerClassName, String fieldName) {
return fieldFilter.shouldTransformFieldAccess( classfile.getName(), fieldOwnerClassName, fieldName );
}
}, classPool
);
}
private boolean alreadyInstrumented(ClassFile classfile) {
String[] intfs = classfile.getInterfaces();
for ( int i = 0; i < intfs.length; i++ ) {
if ( FieldHandled.class.getName().equals( intfs[i] ) ) {
return true;
}
}
return false;
}
}