// $Id: CGLIBLazyInitializer.java 11296 2007-03-18 04:10:09Z scottmarlownovell $
package org.hibernate.proxy.pojo.cglib;
import java.io.Serializable;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import net.sf.cglib.proxy.Callback;
import net.sf.cglib.proxy.CallbackFilter;
import net.sf.cglib.proxy.Enhancer;
import net.sf.cglib.proxy.InvocationHandler;
import net.sf.cglib.proxy.NoOp;
import org.hibernate.HibernateException;
import org.hibernate.LazyInitializationException;
import org.hibernate.proxy.pojo.BasicLazyInitializer;
import org.hibernate.proxy.HibernateProxy;
import org.hibernate.engine.SessionImplementor;
import org.hibernate.type.AbstractComponentType;
import org.hibernate.util.ReflectHelper;
import org.apache.commons.logging.LogFactory;
/**
* A <tt>LazyInitializer</tt> implemented using the CGLIB bytecode generation library
*/
public final class CGLIBLazyInitializer extends BasicLazyInitializer implements InvocationHandler {
private static final CallbackFilter FINALIZE_FILTER = new CallbackFilter() {
public int accept(Method method) {
if ( method.getParameterTypes().length == 0 && method.getName().equals("finalize") ){
return 1;
}
else {
return 0;
}
}
};
private Class[] interfaces;
private boolean constructed = false;
static HibernateProxy getProxy(final String entityName, final Class persistentClass,
final Class[] interfaces, final Method getIdentifierMethod,
final Method setIdentifierMethod, AbstractComponentType componentIdType,
final Serializable id, final SessionImplementor session) throws HibernateException {
// note: interfaces is assumed to already contain HibernateProxy.class
try {
final CGLIBLazyInitializer instance = new CGLIBLazyInitializer(
entityName,
persistentClass,
interfaces,
id,
getIdentifierMethod,
setIdentifierMethod,
componentIdType,
session
);
final HibernateProxy proxy;
Class factory = getProxyFactory(persistentClass, interfaces);
proxy = getProxyInstance(factory, instance);
instance.constructed = true;
return proxy;
}
catch (Throwable t) {
LogFactory.getLog( BasicLazyInitializer.class )
.error( "CGLIB Enhancement failed: " + entityName, t );
throw new HibernateException( "CGLIB Enhancement failed: " + entityName, t );
}
}
public static HibernateProxy getProxy(final Class factory, final String entityName,
final Class persistentClass, final Class[] interfaces,
final Method getIdentifierMethod, final Method setIdentifierMethod,
final AbstractComponentType componentIdType, final Serializable id,
final SessionImplementor session) throws HibernateException {
final CGLIBLazyInitializer instance = new CGLIBLazyInitializer(
entityName,
persistentClass,
interfaces,
id,
getIdentifierMethod,
setIdentifierMethod,
componentIdType,
session
);
final HibernateProxy proxy;
try {
proxy = getProxyInstance(factory, instance);
}
catch (Exception e) {
throw new HibernateException( "CGLIB Enhancement failed: " + persistentClass.getName(), e );
}
instance.constructed = true;
return proxy;
}
private static HibernateProxy getProxyInstance(Class factory, CGLIBLazyInitializer instance) throws InstantiationException, IllegalAccessException {
HibernateProxy proxy;
try {
Enhancer.registerCallbacks(factory, new Callback[]{ instance, null });
proxy = (HibernateProxy)factory.newInstance();
} finally {
// HHH-2481 make sure the callback gets cleared, otherwise the instance stays in a static thread local.
Enhancer.registerCallbacks(factory, null);
}
return proxy;
}
public static Class getProxyFactory(Class persistentClass, Class[] interfaces)
throws HibernateException {
Enhancer e = new Enhancer();
e.setSuperclass( interfaces.length == 1 ? persistentClass : null );
e.setInterfaces(interfaces);
e.setCallbackTypes(new Class[]{
InvocationHandler.class,
NoOp.class,
});
e.setCallbackFilter(FINALIZE_FILTER);
e.setUseFactory(false);
e.setInterceptDuringConstruction( false );
return e.createClass();
}
private CGLIBLazyInitializer(final String entityName, final Class persistentClass,
final Class[] interfaces, final Serializable id, final Method getIdentifierMethod,
final Method setIdentifierMethod, final AbstractComponentType componentIdType,
final SessionImplementor session) {
super(
entityName,
persistentClass,
id,
getIdentifierMethod,
setIdentifierMethod,
componentIdType,
session
);
this.interfaces = interfaces;
}
public Object invoke(final Object proxy, final Method method, final Object[] args) throws Throwable {
if ( constructed ) {
Object result = invoke( method, args, proxy );
if ( result == INVOKE_IMPLEMENTATION ) {
Object target = getImplementation();
try {
final Object returnValue;
if ( ReflectHelper.isPublic( persistentClass, method ) ) {
if ( ! method.getDeclaringClass().isInstance( target ) ) {
throw new ClassCastException( target.getClass().getName() );
}
returnValue = method.invoke( target, args );
}
else {
if ( !method.isAccessible() ) {
method.setAccessible( true );
}
returnValue = method.invoke( target, args );
}
return returnValue == target ? proxy : returnValue;
}
catch ( InvocationTargetException ite ) {
throw ite.getTargetException();
}
}
else {
return result;
}
}
else {
// while constructor is running
if ( method.getName().equals( "getHibernateLazyInitializer" ) ) {
return this;
}
else {
throw new LazyInitializationException( "unexpected case hit, method=" + method.getName() );
}
}
}
protected Object serializableProxy() {
return new SerializableProxy(
getEntityName(),
persistentClass,
interfaces,
getIdentifier(),
getIdentifierMethod,
setIdentifierMethod,
componentIdType
);
}
}