EDIT

 * with a patch. This overriding class appears both in the 'cdmlib-persistence'

 * and the 'cdmlib-remote-webapp' projects to ensure that it is loaded with

 * priority before the original class.

/*

 * Hibernate, Relational Persistence for Idiomatic Java

 *

 * Copyright (c) 2010, 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.type;

import java.io.Serializable;

import java.sql.ResultSet;

import java.sql.SQLException;

import java.util.Map;

import org.dom4j.Element;

import org.dom4j.Node;

import org.hibernate.AssertionFailure;

import org.hibernate.EntityMode;

import org.hibernate.HibernateException;

import org.hibernate.MappingException;

import org.hibernate.engine.internal.ForeignKeys;

import org.hibernate.engine.spi.EntityUniqueKey;

import org.hibernate.engine.spi.Mapping;

import org.hibernate.engine.spi.PersistenceContext;

import org.hibernate.engine.spi.SessionFactoryImplementor;

import org.hibernate.engine.spi.SessionImplementor;

import org.hibernate.internal.util.ReflectHelper;

import org.hibernate.persister.entity.EntityPersister;

import org.hibernate.persister.entity.Joinable;

import org.hibernate.persister.entity.UniqueKeyLoadable;

import org.hibernate.proxy.HibernateProxy;

import org.hibernate.tuple.ElementWrapper;

/**

 * Base for types which map associations to persistent entities.

 *

 * Note : This class overrides the Hibernate EntityType class to provide a

 * workaround for problem in method 'replace'. Need to check if

 * this problem is fixed in later versions of hibernate or open a bug report

 * with a patch. This overriding class appears both in the 'cdmlib-persistence'

 * and the 'cdmlib-remote-webapp' projects to ensure that it is loaded with

 * priority before the original class.

 *

 * @author Gavin King

 */

public abstract class EntityType extends AbstractType implements AssociationType {

	private final TypeFactory.TypeScope scope;

	private final String associatedEntityName;

	protected final String uniqueKeyPropertyName;

	protected final boolean isEmbeddedInXML;

	private final boolean eager;

	private final boolean unwrapProxy;

	private transient Class returnedClass;

	/**

	 * Constructs the requested entity type mapping.

	 *

	 * @param scope The type scope

	 * @param entityName The name of the associated entity.

	 * @param uniqueKeyPropertyName The property-ref name, or null if we

	 * reference the PK of the associated entity.

	 * @param eager Is eager fetching enabled.

	 * @param isEmbeddedInXML Should values of this mapping be embedded in XML modes?

	 * @param unwrapProxy Is unwrapping of proxies allowed for this association; unwrapping

	 * says to return the "implementation target" of lazy prooxies; typically only possible

	 * with lazy="no-proxy".

	 *

	 * @deprecated Use {@link #EntityType(TypeFactory.TypeScope, String, String, boolean, boolean )} instead.

	 * See Jira issue: <a href="https://hibernate.onjira.com/browse/HHH-7771">HHH-7771</a>

	 */

	@Deprecated

	protected EntityType(

			TypeFactory.TypeScope scope,

			String entityName,

			String uniqueKeyPropertyName,

			boolean eager,

			boolean isEmbeddedInXML,

			boolean unwrapProxy) {

		this.scope = scope;

		this.associatedEntityName = entityName;

		this.uniqueKeyPropertyName = uniqueKeyPropertyName;

		this.isEmbeddedInXML = isEmbeddedInXML;

		this.eager = eager;

		this.unwrapProxy = unwrapProxy;

	}

	/**

	 * Constructs the requested entity type mapping.

	 *

	 * @param scope The type scope

	 * @param entityName The name of the associated entity.

	 * @param uniqueKeyPropertyName The property-ref name, or null if we

	 * reference the PK of the associated entity.

	 * @param eager Is eager fetching enabled.

	 * @param unwrapProxy Is unwrapping of proxies allowed for this association; unwrapping

	 * says to return the "implementation target" of lazy prooxies; typically only possible

	 * with lazy="no-proxy".

	 */

	protected EntityType(

			TypeFactory.TypeScope scope,

			String entityName,

			String uniqueKeyPropertyName,

			boolean eager,

			boolean unwrapProxy) {

		this.scope = scope;

		this.associatedEntityName = entityName;

		this.uniqueKeyPropertyName = uniqueKeyPropertyName;

		this.isEmbeddedInXML = true;

		this.eager = eager;

		this.unwrapProxy = unwrapProxy;

	}

	protected TypeFactory.TypeScope scope() {

		return scope;

	}

	/**

	 * An entity type is a type of association type

	 *

	 * @return True.

	 */

	@Override

    public boolean isAssociationType() {

		return true;

	}

	/**

	 * Explicitly, an entity type is an entity type ;)

	 *

	 * @return True.

	 */

	@Override

    public final boolean isEntityType() {

		return true;

	}

	/**

	 * {@inheritDoc}

	 */

	@Override

    public boolean isMutable() {

		return false;

	}

	/**

	 * Generates a string representation of this type.

	 *

	 * @return string rep

	 */

	@Override

    public String toString() {

		return getClass().getName() + '(' + getAssociatedEntityName() + ')';

	}

	/**

	 * For entity types, the name correlates to the associated entity name.

	 */

	@Override

    public String getName() {

		return associatedEntityName;

	}

	/**

	 * Does this association foreign key reference the primary key of the other table?

	 * Otherwise, it references a property-ref.

	 *

	 * @return True if this association reference the PK of the associated entity.

	 */

	public boolean isReferenceToPrimaryKey() {

		return uniqueKeyPropertyName==null;

	}

	@Override

    public String getRHSUniqueKeyPropertyName() {

		return uniqueKeyPropertyName;

	}

	@Override

    public String getLHSPropertyName() {

		return null;

	}

	public String getPropertyName() {

		return null;

	}

	/**

	 * The name of the associated entity.

	 *

	 * @return The associated entity name.

	 */

	public final String getAssociatedEntityName() {

		return associatedEntityName;

	}

	/**

	 * The name of the associated entity.

	 *

	 * @param factory The session factory, for resolution.

	 * @return The associated entity name.

	 */

	@Override

    public String getAssociatedEntityName(SessionFactoryImplementor factory) {

		return getAssociatedEntityName();

	}

	/**

	 * Retrieves the {@link Joinable} defining the associated entity.

	 *

	 * @param factory The session factory.

	 * @return The associated joinable

	 * @throws MappingException Generally indicates an invalid entity name.

	 */

	@Override

    public Joinable getAssociatedJoinable(SessionFactoryImplementor factory) throws MappingException {

		return ( Joinable ) factory.getEntityPersister( associatedEntityName );

	}

	/**

	 * This returns the wrong class for an entity with a proxy, or for a named

	 * entity.  Theoretically it should return the proxy class, but it doesn't.

	 * <p/>

	 * The problem here is that we do not necessarily have a ref to the associated

	 * entity persister (nor to the session factory, to look it up) which is really

	 * needed to "do the right thing" here...

	 *

	 * @return The entiyt class.

	 */

	@Override

    public final Class getReturnedClass() {

		if ( returnedClass == null ) {

			returnedClass = determineAssociatedEntityClass();

		}

		return returnedClass;

	}

	private Class determineAssociatedEntityClass() {

		try {

			return ReflectHelper.classForName( getAssociatedEntityName() );

		}

		catch ( ClassNotFoundException cnfe ) {

			return java.util.Map.class;

		}

	}

	/**

	 * {@inheritDoc}

	 */

	@Override

    public Object nullSafeGet(ResultSet rs, String name, SessionImplementor session, Object owner)

	throws HibernateException, SQLException {

		return nullSafeGet( rs, new String[] {name}, session, owner );

	}

	/**

	 * {@inheritDoc}

	 */

	@Override

    public final Object nullSafeGet(

			ResultSet rs,

			String[] names,

			SessionImplementor session,

			Object owner) throws HibernateException, SQLException {

		return resolve( hydrate(rs, names, session, owner), session, owner );

	}

	/**

	 * Two entities are considered the same when their instances are the same.

	 *

	 *

	 * @param x One entity instance

	 * @param y Another entity instance

	 * @return True if x == y; false otherwise.

	 */

	@Override

    public final boolean isSame(Object x, Object y) {

		return x == y;

	}

	/**

	 * {@inheritDoc}

	 */

	@Override

    public int compare(Object x, Object y) {

		return 0; //TODO: entities CAN be compared, by PK, fix this! -> only if/when we can extract the id values....

	}

	/**

	 * {@inheritDoc}

	 */

	@Override

    public Object deepCopy(Object value, SessionFactoryImplementor factory) {

		return value; //special case ... this is the leaf of the containment graph, even though not immutable

	}

	/**

	 * {@inheritDoc}

	 */

	@Override

    public Object replace(

			Object original,

			Object target,

			SessionImplementor session,

			Object owner,

			Map copyCache) throws HibernateException {

		if ( original == null ) {

			return null;

		}

		Object cached = copyCache.get(original);

		if ( cached != null ) {

			return cached;

		}

		else {

			if ( original == target ) {

				return target;

			}

			if ( session.getContextEntityIdentifier( original ) == null  &&

					ForeignKeys.isTransient( associatedEntityName, original, Boolean.FALSE, session ) ) {

			    // final Object copy = session.getFactory().getEntityPersister( associatedEntityName )

                //  .instantiate( null, session );

			    // changed above call to below, because the associatedEntityName could be an abstract class

			    // in which case it cannot be instantiated

				final Object copy = session.getFactory().getEntityPersister( original.getClass().getName() )

						.instantiate( null, session );

				//TODO: should this be Session.instantiate(Persister, ...)?

				copyCache.put( original, copy );

				return copy;

			}

			else {

				Object id = getIdentifier( original, session );

				if ( id == null ) {

					throw new AssertionFailure("non-transient entity has a null id");

				}

				id = getIdentifierOrUniqueKeyType( session.getFactory() )

						.replace(id, null, session, owner, copyCache);

				return resolve( id, session, owner );

			}

		}

	}

	/**

	 * {@inheritDoc}

	 */

	@Override

    public int getHashCode(Object x, SessionFactoryImplementor factory) {

		EntityPersister persister = factory.getEntityPersister(associatedEntityName);

		if ( !persister.canExtractIdOutOfEntity() ) {

			return super.getHashCode( x );

		}

		final Serializable id;

		if (x instanceof HibernateProxy) {

			id = ( (HibernateProxy) x ).getHibernateLazyInitializer().getIdentifier();

		}

		else {

			final Class mappedClass = persister.getMappedClass();

			if ( mappedClass.isAssignableFrom( x.getClass() ) ) {

				id = persister.getIdentifier( x );

			}

			else {

				id = (Serializable) x;

			}

		}

		return persister.getIdentifierType().getHashCode( id, factory );

	}

	@Override

	public boolean isEqual(Object x, Object y, SessionFactoryImplementor factory) {

		// associations (many-to-one and one-to-one) can be null...

		if ( x == null || y == null ) {

			return x == y;

		}

		EntityPersister persister = factory.getEntityPersister(associatedEntityName);

		if ( !persister.canExtractIdOutOfEntity() ) {

			return super.isEqual(x, y );

		}

		final Class mappedClass = persister.getMappedClass();

		Serializable xid;

		if (x instanceof HibernateProxy) {

			xid = ( (HibernateProxy) x ).getHibernateLazyInitializer()

					.getIdentifier();

		}

		else {

			if ( mappedClass.isAssignableFrom( x.getClass() ) ) {

				xid = persister.getIdentifier( x );

			}

			else {

				//JPA 2 case where @IdClass contains the id and not the associated entity

				xid = (Serializable) x;

			}

		}

		Serializable yid;

		if (y instanceof HibernateProxy) {

			yid = ( (HibernateProxy) y ).getHibernateLazyInitializer()

					.getIdentifier();

		}

		else {

			if ( mappedClass.isAssignableFrom( y.getClass() ) ) {

				yid = persister.getIdentifier( y );

			}

			else {

				//JPA 2 case where @IdClass contains the id and not the associated entity

				yid = (Serializable) y;

			}

		}

		return persister.getIdentifierType()

				.isEqual(xid, yid, factory);

	}

	/**

	 * {@inheritDoc}

	 */

	@Override

    public boolean isEmbeddedInXML() {

		return isEmbeddedInXML;

	}

	/**

	 * {@inheritDoc}

	 */

	@Override

    public boolean isXMLElement() {

		return isEmbeddedInXML;

	}

	/**

	 * {@inheritDoc}

	 */

	@Override

    public Object fromXMLNode(Node xml, Mapping factory) throws HibernateException {

		if ( !isEmbeddedInXML ) {

			return getIdentifierType(factory).fromXMLNode(xml, factory);

		}

		else {

			return xml;

		}

	}

	/**

	 * {@inheritDoc}

	 */

	@Override

    public void setToXMLNode(Node node, Object value, SessionFactoryImplementor factory) throws HibernateException {

		if ( !isEmbeddedInXML ) {

			getIdentifierType(factory).setToXMLNode(node, value, factory);

		}

		else {

			Element elt = (Element) value;

			replaceNode( node, new ElementWrapper(elt) );

		}

	}

	@Override

    public String getOnCondition(String alias, SessionFactoryImplementor factory, Map enabledFilters)

	throws MappingException {

		if ( isReferenceToPrimaryKey() ) { //TODO: this is a bit arbitrary, expose a switch to the user?

			return "";

		}

		else {

			return getAssociatedJoinable( factory ).filterFragment( alias, enabledFilters );

		}

	}

	/**

	 * Resolve an identifier or unique key value

	 */

	@Override

    public Object resolve(Object value, SessionImplementor session, Object owner) throws HibernateException {

		if ( isNotEmbedded( session ) ) {

			return value;

		}

		if ( value == null ) {

			return null;

		}

		else {

			if ( isNull( owner, session ) ) {

				return null; //EARLY EXIT!

			}

			if ( isReferenceToPrimaryKey() ) {

				return resolveIdentifier( (Serializable) value, session );

			}

			else {

				return loadByUniqueKey( getAssociatedEntityName(), uniqueKeyPropertyName, value, session );

			}

		}

	}

	@Override

    public Type getSemiResolvedType(SessionFactoryImplementor factory) {

		return factory.getEntityPersister( associatedEntityName ).getIdentifierType();

	}

	protected final Object getIdentifier(Object value, SessionImplementor session) throws HibernateException {

		if ( isNotEmbedded(session) ) {

			return value;

		}

		if ( isReferenceToPrimaryKey() ) {

			return ForeignKeys.getEntityIdentifierIfNotUnsaved( getAssociatedEntityName(), value, session ); //tolerates nulls

		}

		else if ( value == null ) {

			return null;

		}

		else {

			EntityPersister entityPersister = session.getFactory().getEntityPersister( getAssociatedEntityName() );

			Object propertyValue = entityPersister.getPropertyValue( value, uniqueKeyPropertyName );

			// We now have the value of the property-ref we reference.  However,

			// we need to dig a little deeper, as that property might also be

			// an entity type, in which case we need to resolve its identitifier

			Type type = entityPersister.getPropertyType( uniqueKeyPropertyName );

			if ( type.isEntityType() ) {

				propertyValue = ( ( EntityType ) type ).getIdentifier( propertyValue, session );

			}

			return propertyValue;

		}

	}

	/**

	 * @deprecated To be removed in 5.  Removed as part of removing the notion of DOM entity-mode.

	 * See Jira issue: <a href="https://hibernate.onjira.com/browse/HHH-7771">HHH-7771</a>

	 */

	@Deprecated

	protected boolean isNotEmbedded(SessionImplementor session) {

//		return !isEmbeddedInXML;

		return false;

	}

	/**

	 * Generate a loggable representation of an instance of the value mapped by this type.

	 *

	 * @param value The instance to be logged.

	 * @param factory The session factory.

	 * @return The loggable string.

	 * @throws HibernateException Generally some form of resolution problem.

	 */

	@Override

    public String toLoggableString(Object value, SessionFactoryImplementor factory) {

		if ( value == null ) {

			return "null";

		}

		EntityPersister persister = factory.getEntityPersister( associatedEntityName );

		StringBuilder result = new StringBuilder().append( associatedEntityName );

		if ( persister.hasIdentifierProperty() ) {

			final EntityMode entityMode = persister.getEntityMode();

			final Serializable id;

			if ( entityMode == null ) {

				if ( isEmbeddedInXML ) {

					throw new ClassCastException( value.getClass().getName() );

				}

				id = ( Serializable ) value;

			} else if ( value instanceof HibernateProxy ) {

				HibernateProxy proxy = ( HibernateProxy ) value;

				id = proxy.getHibernateLazyInitializer().getIdentifier();

			}

			else {

				id = persister.getIdentifier( value );

			}

			result.append( '#' )

				.append( persister.getIdentifierType().toLoggableString( id, factory ) );

		}

		return result.toString();

	}

	/**

	 * Is the association modeled here defined as a 1-1 in the database (physical model)?

	 *

	 * @return True if a 1-1 in the database; false otherwise.

	 */

	public abstract boolean isOneToOne();

	/**

	 * Is the association modeled here a 1-1 according to the logical moidel?

	 *

	 * @return True if a 1-1 in the logical model; false otherwise.

	 */

	public boolean isLogicalOneToOne() {

		return isOneToOne();

	}

	/**

	 * Convenience method to locate the identifier type of the associated entity.

	 *

	 * @param factory The mappings...

	 * @return The identifier type

	 */

	Type getIdentifierType(Mapping factory) {

		return factory.getIdentifierType( getAssociatedEntityName() );

	}

	/**

	 * Convenience method to locate the identifier type of the associated entity.

	 *

	 * @param session The originating session

	 * @return The identifier type

	 */

	Type getIdentifierType(SessionImplementor session) {

		return getIdentifierType( session.getFactory() );

	}

	/**

	 * Determine the type of either (1) the identifier if we reference the

	 * associated entity's PK or (2) the unique key to which we refer (i.e.

	 * the property-ref).

	 *

	 * @param factory The mappings...

	 * @return The appropriate type.

	 * @throws MappingException Generally, if unable to resolve the associated entity name

	 * or unique key property name.

	 */

	public final Type getIdentifierOrUniqueKeyType(Mapping factory) throws MappingException {

		if ( isReferenceToPrimaryKey() ) {

			return getIdentifierType(factory);

		}

		else {

			Type type = factory.getReferencedPropertyType( getAssociatedEntityName(), uniqueKeyPropertyName );

			if ( type.isEntityType() ) {

				type = ( ( EntityType ) type).getIdentifierOrUniqueKeyType( factory );

			}

			return type;

		}

	}

	/**

	 * The name of the property on the associated entity to which our FK

	 * refers

	 *

	 * @param factory The mappings...

	 * @return The appropriate property name.

	 * @throws MappingException Generally, if unable to resolve the associated entity name

	 */

	public final String getIdentifierOrUniqueKeyPropertyName(Mapping factory)

	throws MappingException {

		if ( isReferenceToPrimaryKey() ) {

			return factory.getIdentifierPropertyName( getAssociatedEntityName() );

		}

		else {

			return uniqueKeyPropertyName;

		}

	}

	protected abstract boolean isNullable();

	/**

	 * Resolve an identifier via a load.

	 *

	 * @param id The entity id to resolve

	 * @param session The orginating session.

	 * @return The resolved identifier (i.e., loaded entity).

	 * @throws org.hibernate.HibernateException Indicates problems performing the load.

	 */

	protected final Object resolveIdentifier(Serializable id, SessionImplementor session) throws HibernateException {

		boolean isProxyUnwrapEnabled = unwrapProxy &&

				session.getFactory()

						.getEntityPersister( getAssociatedEntityName() )

						.isInstrumented();

		Object proxyOrEntity = session.internalLoad(

				getAssociatedEntityName(),

				id,

				eager,

				isNullable() && !isProxyUnwrapEnabled

		);

		if ( proxyOrEntity instanceof HibernateProxy ) {

			( ( HibernateProxy ) proxyOrEntity ).getHibernateLazyInitializer()

					.setUnwrap( isProxyUnwrapEnabled );

		}

		return proxyOrEntity;

	}

	protected boolean isNull(Object owner, SessionImplementor session) {

		return false;

	}

	/**

	 * Load an instance by a unique key that is not the primary key.

	 *

	 * @param entityName The name of the entity to load

	 * @param uniqueKeyPropertyName The name of the property defining the uniqie key.

	 * @param key The unique key property value.

	 * @param session The originating session.

	 * @return The loaded entity

	 * @throws HibernateException generally indicates problems performing the load.

	 */

	public Object loadByUniqueKey(

			String entityName,

			String uniqueKeyPropertyName,

			Object key,

			SessionImplementor session) throws HibernateException {

		final SessionFactoryImplementor factory = session.getFactory();

		UniqueKeyLoadable persister = ( UniqueKeyLoadable ) factory.getEntityPersister( entityName );

		//TODO: implement caching?! proxies?!

		EntityUniqueKey euk = new EntityUniqueKey(

				entityName,

				uniqueKeyPropertyName,

				key,

				getIdentifierOrUniqueKeyType( factory ),

				persister.getEntityMode(),

				session.getFactory()

		);

		final PersistenceContext persistenceContext = session.getPersistenceContext();

		Object result = persistenceContext.getEntity( euk );

		if ( result == null ) {

			result = persister.loadByUniqueKey( uniqueKeyPropertyName, key, session );

		}

		return result == null ? null : persistenceContext.proxyFor( result );

	}

}