Validation of proxy declaration in mapping files is broken ?

vikas_s · **Posted:** Tue Mar 14, 2006 7:41 am

Hi,

In a particular parent-child use case, my object graph looks like this :

Code:

[ParentImpl] <implements> [ParentInterface]
[ChildInterface] <extends> [ParentInterface]
[ChildImpl] <extends> [ParentImpl], <implements> [ChildInterface]

While mapping them as hibernate entities, I had specified "proxy=[ParentImpl]" for the parent class and "proxy=[ChildInterface]" for the child one. However, this resulted in Hibernate cribbing "org.hibernate.MappingException: proxy must be either an interface, or the class itself: [ChildImpl]". This looked strange since the proxy specified for child was indeed an interface (as mentioned above).

From the stack trace, I was able to get the piece of code that does this validation. Here is it, from org.hibernate.tuple.PojoTuplizer.buildProxyFactory(...),with my comments added :

Code:

    [...]
Class mappedClass = persistentClass.getMappedClass();
        Class proxyInterface = persistentClass.getProxyInterface();

        if ( proxyInterface!=null && !mappedClass.equals( proxyInterface ) ) {
            if ( !proxyInterface.isInterface() ) {
                throw new MappingException(
                        "proxy must be either an interface, or the class itself: " +
                        getEntityName()
                );
            }
            proxyInterfaces.add( proxyInterface );
        }

        if ( mappedClass.isInterface() ) {
            proxyInterfaces.add( mappedClass );
        }

        Iterator iter = persistentClass.getSubclassIterator();
        while ( iter.hasNext() ) {
            Subclass subclass = ( Subclass ) iter.next();
            Class subclassProxy = subclass.getProxyInterface();
            Class subclassClass = subclass.getMappedClass();

            // *** [Vikas S] : This correctly checks subclassProxy ***
            if ( subclassProxy!=null && !subclassClass.equals( subclassProxy ) ) {

                // *** [Vikas S] : But why proxyInterface ??? Shouldn't this be subclassProxy ??? ***
                if ( !proxyInterface.isInterface() ) {
                    throw new MappingException(
                            "proxy must be either an interface, or the class itself: " +
                            subclass.getEntityName()
                    );
                }
                proxyInterfaces.add( subclassProxy );
            }
        }
      [...]

As mentioned in my inline comment, while iterating through the sub-class mappings it is validating proxyInterface (proxy defined for parent) instead of subclassProxy. Is this intended ??