protected EntityType(String entityName,
    String uniqueKeyPropertyName,
    boolean eager,
    boolean isEmbeddedInXML,
    boolean unwrapProxy) 
{
		this.associatedEntityName = entityName;
		this.uniqueKeyPropertyName = uniqueKeyPropertyName;
		this.isEmbeddedInXML = isEmbeddedInXML;
		this.eager = eager;
		this.unwrapProxy = unwrapProxy;
}

 public int compare(Object x,
    Object y,
    EntityMode entityMode) 
{
		return 0; //TODO: entities CAN be compared, by PK, fix this!
}

 public Object deepCopy(Object value,
    EntityMode entityMode,
    SessionFactoryImplementor factory) 
{
		return value; //special case ... this is the leaf of the containment graph, even though not immutable
}

 public Object fromXMLNode(Node xml,
    Mapping factory) throws HibernateException 
{
		if ( !isEmbeddedInXML ) {
			return getIdentifierType(factory).fromXMLNode(xml, factory);
		}
		else {
			return xml;
		}
}

 public final String getAssociatedEntityName() 
{
		return associatedEntityName;
}

 public String getAssociatedEntityName(SessionFactoryImplementor factory) 
{
		return getAssociatedEntityName();
}

 public Joinable getAssociatedJoinable(SessionFactoryImplementor factory) throws MappingException 
{
		return (Joinable) factory.getEntityPersister(associatedEntityName);
}

 public int getHashCode(Object x,
    EntityMode entityMode,
    SessionFactoryImplementor factory) 
{
		EntityPersister persister = factory.getEntityPersister(associatedEntityName);
		if ( !persister.canExtractIdOutOfEntity() ) {
			return super.getHashCode(x, entityMode);
		}
		final Serializable id;
		if (x instanceof HibernateProxy) {
			id = ( (HibernateProxy) x ).getHibernateLazyInitializer().getIdentifier();
		}
		else {
			id = persister.getIdentifier(x, entityMode);
		}
		return persister.getIdentifierType().getHashCode(id, entityMode, factory);
}

 protected final Object getIdentifier(Object value,
    SessionImplementor session) throws HibernateException 
{
		if ( isNotEmbedded(session) ) return value;
		if ( isReferenceToPrimaryKey() ) {
			return ForeignKeys.getEntityIdentifierIfNotUnsaved(associatedEntityName, value, session); //tolerates nulls
		}
		else if (value==null) {
			return null;
		}
		else {
			return session.getFactory()
			        .getEntityPersister( getAssociatedEntityName() )
			        .getPropertyValue( value, uniqueKeyPropertyName, session.getEntityMode() );
		}
}

 public final String getIdentifierOrUniqueKeyPropertyName(Mapping factory) throws MappingException 
{
		if ( isReferenceToPrimaryKey() ) {
			return factory.getIdentifierPropertyName( getAssociatedEntityName() );
		}
		else {
			return uniqueKeyPropertyName;
		}
}

 public final Type getIdentifierOrUniqueKeyType(Mapping factory) throws MappingException 
{
		if ( isReferenceToPrimaryKey() ) {
			return getIdentifierType(factory);
		}
		else {
			return factory.getReferencedPropertyType( getAssociatedEntityName(), uniqueKeyPropertyName );
		}
}

 Type getIdentifierType(Mapping factory) 
{
		return factory.getIdentifierType( getAssociatedEntityName() );
}

 Type getIdentifierType(SessionImplementor session) throws MappingException 
{
		return getIdentifierType( session.getFactory() );
}

 public String getLHSPropertyName() 
{
		return null;
}

 public String getName() 
{
 return associatedEntityName;
}

 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);
		}
}

 public String getPropertyName() 
{
		return null;
}

 public String getRHSUniqueKeyPropertyName() 
{
		return uniqueKeyPropertyName;
}

 public final Class getReturnedClass() 
{
		try {
			return ReflectHelper.classForName(associatedEntityName);
		}
		catch (ClassNotFoundException cnfe) {
			return java.util.Map.class;
		}
}

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.

 public Type getSemiResolvedType(SessionFactoryImplementor factory) 
{
		return factory.getEntityPersister(associatedEntityName).getIdentifierType();
}

 public boolean isAssociationType() 
{
		return true;
}

 public boolean isEmbeddedInXML() 
{
		return isEmbeddedInXML;
}

 public final boolean isEntityType() 
{
		return true;
}

 public boolean isEqual(Object x,
    Object y,
    EntityMode entityMode,
    SessionFactoryImplementor factory) 
{
		EntityPersister persister = factory.getEntityPersister(associatedEntityName);
		if ( !persister.canExtractIdOutOfEntity() ) {
			return super.isEqual(x, y, entityMode);
		}
		Serializable xid;
		if (x instanceof HibernateProxy) {
			xid = ( (HibernateProxy) x ).getHibernateLazyInitializer()
					.getIdentifier();
		}
		else {
			xid = persister.getIdentifier(x, entityMode);
		}
		Serializable yid;
		if (y instanceof HibernateProxy) {
			yid = ( (HibernateProxy) y ).getHibernateLazyInitializer()
					.getIdentifier();
		}
		else {
			yid = persister.getIdentifier(y, entityMode);
		}
		return persister.getIdentifierType()
				.isEqual(xid, yid, entityMode, factory);
}

 public boolean isMutable() 
{
		return false;
}

 protected boolean isNotEmbedded(SessionImplementor session) 
{
		return !isEmbeddedInXML && session.getEntityMode()==EntityMode.DOM4J;
}

 protected boolean isNull(Object owner,
    SessionImplementor session) 
{
		return false;
}

 abstract protected boolean isNullable()

 abstract public boolean isOneToOne()

 public boolean isReferenceToPrimaryKey() 
{
		return uniqueKeyPropertyName==null;
}

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

 public final boolean isSame(Object x,
    Object y,
    EntityMode entityMode) 
{
		return x==y;
}

 public boolean isXMLElement() 
{
		return isEmbeddedInXML;
}

 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 ),
				session.getEntityMode(), 
				session.getFactory()
			);
		final PersistenceContext persistenceContext = session.getPersistenceContext();
		Object result = persistenceContext.getEntity(euk);
		//if ( result==null && !persistenceContext.isNonExistant(euk) ) {
		if ( result==null ) {
			result = persister.loadByUniqueKey(uniqueKeyPropertyName, key, session);
		}
		return result==null ? null : persistenceContext.proxyFor(result);
}

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

 public Object nullSafeGet(ResultSet rs,
    String name,
    SessionImplementor session,
    Object owner) throws HibernateException, SQLException 
{
		return nullSafeGet( rs, new String[] {name}, session, owner );
}

 public final Object nullSafeGet(ResultSet rs,
    String[] names,
    SessionImplementor session,
    Object owner) throws HibernateException, SQLException 
{
		return resolve( hydrate(rs, names, session, owner), session, owner );
}

 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;
			//TODO: can this ever get called????
			Object id = getIdentifier(original, session);
			if (id==null) throw new AssertionFailure("cannot copy a reference to an object with a null id");
			id = getIdentifierOrUniqueKeyType( session.getFactory() )
					.replace(id, null, session, owner, copyCache);
			return resolve(id, session, owner);
		}
}

 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 
					);
			}
		}
}

Resolve an identifier or unique key value

 protected final Object resolveIdentifier(Serializable id,
    SessionImplementor session) throws HibernateException 
{
		
		boolean isProxyUnwrapEnabled = unwrapProxy && 
				session.getFactory()
						.getEntityPersister( getAssociatedEntityName() )
						.isInstrumented( session.getEntityMode() );
		Object proxyOrEntity = session.internalLoad( 
				getAssociatedEntityName(), 
				id, 
				eager, 
				isNullable() && !isProxyUnwrapEnabled
			);
		if (proxyOrEntity instanceof HibernateProxy) {
			( (HibernateProxy) proxyOrEntity ).getHibernateLazyInitializer()
					.setUnwrap(isProxyUnwrapEnabled);
		}
		return proxyOrEntity;
}

Resolve an identifier

 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) );
		}
}

 public String toLoggableString(Object value,
    SessionFactoryImplementor factory) throws HibernateException 
{
		if (value==null) return "null";
		EntityPersister persister = factory.getEntityPersister(associatedEntityName);
		StringBuffer result = new StringBuffer()
			.append(associatedEntityName);
		if ( persister.hasIdentifierProperty() ) {
			//TODO: use of a guess here is bad...
			final EntityMode entityMode = persister.guessEntityMode(value);
			final Serializable id;
			if (entityMode==null) {
				if ( isEmbeddedInXML ) {
					throw new ClassCastException( value.getClass().getName() );
				}
				id = (Serializable) value;
			}
			else {
				id = getIdentifier( value, persister, entityMode );
			}
			result.append('#")
				.append( persister.getIdentifierType().toLoggableString(id, factory) );
		}
		return result.toString();
}

 public String toString() 
{
		return getClass().getName() + '(" + getAssociatedEntityName() + ')";
}