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DataNucleus Enhancer is a Java byte-code enhancer for use with DataNucleus.
/**********************************************************************
Copyright (c) 2007 Andy Jefferson and others. All rights reserved.
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.
Contributors:
...
**********************************************************************/
package org.datanucleus.enhancer.asm;
import java.io.ObjectStreamClass;
import java.io.Serializable;
import java.security.AccessController;
import java.security.PrivilegedAction;
import java.util.Iterator;
import java.util.List;
import javax.jdo.spi.PersistenceCapable;
import org.datanucleus.enhancer.ClassEnhancer;
import org.datanucleus.enhancer.ClassField;
import org.datanucleus.enhancer.DataNucleusEnhancer;
import org.datanucleus.enhancer.asm.method.JdoGetViaCheck;
import org.datanucleus.enhancer.asm.method.JdoSetViaCheck;
import org.datanucleus.enhancer.asm.method.DefaultConstructor;
import org.datanucleus.enhancer.asm.method.InitClass;
import org.datanucleus.enhancer.asm.method.JdoGetViaMediate;
import org.datanucleus.enhancer.asm.method.JdoSetViaMediate;
import org.datanucleus.enhancer.asm.method.JdoGetNormal;
import org.datanucleus.enhancer.asm.method.JdoSetNormal;
import org.datanucleus.enhancer.asm.method.WriteObject;
import org.datanucleus.metadata.AbstractClassMetaData;
import org.datanucleus.metadata.AbstractMemberMetaData;
import org.datanucleus.metadata.ClassPersistenceModifier;
import org.datanucleus.metadata.FieldPersistenceModifier;
import org.datanucleus.metadata.PropertyMetaData;
import org.datanucleus.util.ClassUtils;
import org.datanucleus.util.Localiser;
import org.datanucleus.util.StringUtils;
import org.objectweb.asm.ClassAdapter;
import org.objectweb.asm.ClassVisitor;
import org.objectweb.asm.FieldVisitor;
import org.objectweb.asm.MethodVisitor;
import org.objectweb.asm.Opcodes;
import org.objectweb.asm.Type;
/**
* Adapter visitor class for providing enhancement of an existing class using ASM.
* Is created with its own ClassWriter, and is passed to a ClassReader to visit the class.
* All parts of the class to be enhanced are fed through the different visitXXX methods here
* allowing intervention to either enhance an existing method, or to add on new fields/methods/interfaces.
*/
public class JdoClassAdapter extends ClassAdapter
{
/** Localisation of messages */
protected static final Localiser LOCALISER = Localiser.getInstance("org.datanucleus.enhancer.Localisation",
ClassEnhancer.class.getClassLoader());
/** The underlying enhancer. */
protected ASMClassEnhancer enhancer;
/** Whether a default constructor is present. Set if found, and then processed in visitEnd. */
protected boolean hasDefaultConstructor = false;
/** Whether the field serialVersionUID is present. Set if found, and processed in visitEnd. */
protected boolean hasSerialVersionUID = false;
/** Whether the field jdoDetachedState is present. Set if found, and processed in visitEnd. */
protected boolean hasJdoDetachedState = false;
/** Whether the method writeObject(ObjectOutputStream) is present. Set if found, and processed in visitEnd. */
protected boolean hasWriteObject = false;
/** Whether the class already has a static init block. Set if found, and processed in visitEnd. */
protected boolean hasStaticInitialisation = false;
/**
* Constructor.
* If the writer is null it means we just have to check the enhancement status
* @param cv The writer visitor
*/
public JdoClassAdapter(ClassVisitor cv, ASMClassEnhancer enhancer)
{
super(cv);
this.enhancer = enhancer;
}
/**
* Method called to visit the header of the class.
* @param version Version of this class
* @param access Access for the class
* @param name name of the class
* @param signature Signature of the class
* @param superName Superclass name (if any)
* @param interfaces Interface(s) implemented
*/
public void visit(int version, int access, String name, String signature, String superName, String[] interfaces)
{
if (enhancer.getClassMetaData().getPersistenceModifier() == ClassPersistenceModifier.PERSISTENCE_CAPABLE)
{
// Check if the class already implements PersistenceCapable/Detachable interfaces
boolean alreadyPersistenceCapable = false;
boolean alreadyDetachable = false;
boolean needsPersistenceCapable = false;
boolean needsDetachable = false;
int numInterfaces = 0;
if (interfaces != null && interfaces.length > 0)
{
numInterfaces = interfaces.length;
for (int i=0;i 0)
{
for (int i=0;i") && desc != null && desc.equals("()V"))
{
// Check for default constructor
hasDefaultConstructor = true;
}
if (name.equals("writeObject") && desc != null && desc.equals("(Ljava/io/ObjectOutputStream;)V"))
{
// Has writeObject() for use in serialisation
hasWriteObject = true;
}
if (name.equals("") && desc != null && desc.equals("()V"))
{
hasStaticInitialisation = true;
}
MethodVisitor mv = cv.visitMethod(access, name, desc, signature, exceptions);
if (mv == null)
{
return null;
}
if (name.equals("jdoPreClear") || name.equals("jdoPostLoad"))
{
// jdoPreClear/jdoPostLoad should not be enhanced (JDO2 spec [10.1, 10.3]
return mv;
}
else if (name.equals("readObject") &&
(desc.equals("(Ljava/io/ObjectOutputStream;)V") || desc.equals("(Ljava/io/ObjectInputStream;)V")))
{
// readObject(ObjectInputStream), readObject(ObjectOutputStream) should not be enhanced (JDO2 spec [21.6])
return mv;
}
String propGetterName = ClassUtils.getFieldNameForJavaBeanGetter(name);
String propSetterName = ClassUtils.getFieldNameForJavaBeanSetter(name);
if (propGetterName != null)
{
AbstractMemberMetaData mmd = enhancer.getClassMetaData().getMetaDataForMember(propGetterName);
if (mmd != null && mmd instanceof PropertyMetaData && mmd.getPersistenceModifier() != FieldPersistenceModifier.NONE)
{
// Property getter method "getXXX" - generated jdoGetXXX
return new JdoPropertyGetterAdapter(mv, enhancer, name, desc, mmd, cv);
}
}
else if (propSetterName != null)
{
AbstractMemberMetaData mmd = enhancer.getClassMetaData().getMetaDataForMember(propSetterName);
if (mmd != null && mmd instanceof PropertyMetaData && mmd.getPersistenceModifier() != FieldPersistenceModifier.NONE)
{
// Property setter method "setXXX" - generates jdoSetXXX
return new JdoPropertySetterAdapter(mv, enhancer, name, desc, mmd, cv);
}
}
// normal method, so just enhance it
return new JdoMethodAdapter(mv, enhancer, name, desc);
}
/**
* Method called at the end of the class.
*/
public void visitEnd()
{
AbstractClassMetaData cmd = enhancer.getClassMetaData();
if (cmd.getPersistenceModifier() == ClassPersistenceModifier.PERSISTENCE_CAPABLE)
{
// Add any new fields
List fields = enhancer.getFieldsList();
Iterator fieldsIter = fields.iterator();
while (fieldsIter.hasNext())
{
ClassField field = (ClassField)fieldsIter.next();
if (field.getName().equals(enhancer.getDetachedStateFieldName()) && hasJdoDetachedState)
{
// No need to add this field since exists
continue;
}
if (DataNucleusEnhancer.LOGGER.isDebugEnabled())
{
DataNucleusEnhancer.LOGGER.debug(LOCALISER.msg("Enhancer.AddField",
((Class)field.getType()).getName() + " " + field.getName()));
}
cv.visitField(field.getAccess(), field.getName(), Type.getDescriptor((Class)field.getType()), null, null);
}
if (!hasStaticInitialisation)
{
// Add a static initialisation block for the class since nothing added yet
InitClass method = InitClass.getInstance(enhancer);
method.initialise(cv);
method.execute();
method.close();
}
if (!hasDefaultConstructor && enhancer.hasOption(ClassEnhancer.OPTION_GENERATE_DEFAULT_CONSTRUCTOR))
{
// Add a default constructor
DefaultConstructor ctr = DefaultConstructor.getInstance(enhancer);
ctr.initialise(cv);
ctr.execute();
ctr.close();
}
// Add any new methods
List methods = enhancer.getMethodsList();
Iterator methodsIter = methods.iterator();
while (methodsIter.hasNext())
{
ASMClassMethod method = (ASMClassMethod)methodsIter.next();
method.initialise(cv);
method.execute();
method.close();
}
if (Serializable.class.isAssignableFrom(enhancer.cls))
{
// Class is Serializable
if (!hasSerialVersionUID)
{
// Needs "serialVersionUID" field
Long uid = null;
try
{
uid = (Long) AccessController.doPrivileged(new PrivilegedAction()
{
public Object run()
{
return Long.valueOf(ObjectStreamClass.lookup(enhancer.getClassEnhanced()).getSerialVersionUID());
}
});
}
catch (Throwable e)
{
DataNucleusEnhancer.LOGGER.warn(StringUtils.getStringFromStackTrace(e));
}
ClassField cf = new ClassField(enhancer, enhancer.getSerialVersionUidFieldName(),
Opcodes.ACC_PRIVATE | Opcodes.ACC_STATIC | Opcodes.ACC_FINAL, long.class, uid);
if (DataNucleusEnhancer.LOGGER.isDebugEnabled())
{
DataNucleusEnhancer.LOGGER.debug(LOCALISER.msg("Enhancer.AddField",
((Class)cf.getType()).getName() + " " + cf.getName()));
}
cv.visitField(cf.getAccess(), cf.getName(), Type.getDescriptor((Class)cf.getType()), null, cf.getInitialValue());
}
if (!hasWriteObject)
{
ASMClassMethod method = WriteObject.getInstance(enhancer);
method.initialise(cv);
method.execute();
method.close();
}
}
// Add jdoGetXXX, jdoSetXXX for each of the (managed) fields/properties
AbstractMemberMetaData[] fmds = cmd.getManagedMembers();
for (int i = 0; i < fmds.length; i++)
{
if (fmds[i].getPersistenceModifier() == FieldPersistenceModifier.NONE)
{
// Field/Property is not persistent so ignore
continue;
}
byte jdoFlag = fmds[i].getPersistenceFlags();
ASMClassMethod getMethod = null;
ASMClassMethod setMethod = null;
if (fmds[i] instanceof PropertyMetaData)
{
// jdoGetXXX, jdoSetXXX for property are generated when processing existing getXXX, setXXX methods
}
else
{
// Generate jdoGetXXX, jdoSetXXX for field
if ((jdoFlag & PersistenceCapable.MEDIATE_READ) == PersistenceCapable.MEDIATE_READ)
{
getMethod = new JdoGetViaMediate(enhancer, fmds[i]);
}
else if ((jdoFlag & PersistenceCapable.CHECK_READ) == PersistenceCapable.CHECK_READ)
{
getMethod = new JdoGetViaCheck(enhancer, fmds[i]);
}
else
{
getMethod = new JdoGetNormal(enhancer, fmds[i]);
}
if ((jdoFlag & PersistenceCapable.MEDIATE_WRITE) == PersistenceCapable.MEDIATE_WRITE)
{
setMethod = new JdoSetViaMediate(enhancer, fmds[i]);
}
else if ((jdoFlag & PersistenceCapable.CHECK_WRITE) == PersistenceCapable.CHECK_WRITE)
{
setMethod = new JdoSetViaCheck(enhancer, fmds[i]);
}
else
{
setMethod = new JdoSetNormal(enhancer, fmds[i]);
}
}
if (getMethod != null)
{
getMethod.initialise(cv);
getMethod.execute();
getMethod.close();
}
if (setMethod != null)
{
setMethod.initialise(cv);
setMethod.execute();
setMethod.close();
}
}
}
cv.visitEnd();
}
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