Discussion regarding design changes in bytecode enhancement

Experiment1.java

public class Parent  {

    Long id;

    @OneToMany(
        mappedBy = "parent",
        cascade = {CascadeType.ALL},
        fetch = FetchType.LAZY
    )
    List<Child> children;

    public List<Child> getChildren() {
        return this.$$_hibernate_read_children();
    }

    public void setChildren(List<Child> children) {
        this.$$_hibernate_write_children(children);
    }

    // This is what exists today 

    public List $$_hibernate_read_children() {
        if(this.$$_hibernate_getInterceptor() != null) {
            this.children = (List)this.$$_hibernate_getInterceptor().readObject(this, "children", this.children);
        }

        return this.children;
    }

    public void $$_hibernate_write_children(List var1) {
        if(this.children != null && Hibernate.isPropertyInitialized(this.children, "parent")) {
            Object[] var2 = this.children.toArray();

            for(int var3 = 0; var3 < var2.length; ++var3) {
                Child var4 = (Child)var2[var3];
                if(var1 == null || !var1.contains(var4)) {
                    var4.$$_hibernate_write_parent((Parent)null);
                }
            }
        }

        if(!EqualsHelper.areEqual(this.children, var1)) {
            this.$$_hibernate_trackChange("children");
        }

        List var10 = var1;
        if(this.$$_hibernate_getInterceptor() != null) {
            var10 = (List)this.$$_hibernate_getInterceptor().writeObject(this, "children", this.children, var1);
        }

        this.children = var10;
        Object var6 = null;
        if(var1 != null && Hibernate.isPropertyInitialized(var1, "parent")) {
            Object[] var7 = var1.toArray();

            for(int var8 = 0; var8 < var7.length; ++var8) {
                Child var9 = (Child)var7[var8];
                if(Hibernate.isPropertyInitialized(var9, "parent") && var9.$$_hibernate_read_parent() != this) {
                    var9.$$_hibernate_write_parent(this);
                }
            }
        }
    }

    // THIS IS FOR DISCUSSION

    public enum $$_hibernate_enhanced_attribute_enumer implements EnhancedAttributeEnumeration {
        children
    }

    // I'm considering adding a few static methods to deal with the interception --- let's just say they go on Enhancer class for now

    public List $$_hibernate_read_children() {
        // thos code fragment is only injected if there is lazy loading properties
        if( this.$$_hibernate_getInterceptor() != null ) { 
            this.children = (List) this.$$_hibernate_getInterceptor().readObject( this, EnhancedAttribute.children, this.children );
        }
        return this.children;
    }

    public void $$_hibernate_write_children(List var1) {
        Enhancer.disassociateOneToMany( EnhancedAttribute.children, this.children, "parent"); // iterates over this.children and call $$_hibernate_write_parent(null)

        Enhancer.dirtyCheck( EnhancedAttribute.children, this.children, var1 ); // The logic here is simple, but still ... for completeness

        if( this.$$_hibernate_getInterceptor() != null ) { 
            this.children = (List) this.$$_hibernate_getInterceptor().writeObject( this, EnhancedAttribute.children, this.children );
        }
        
        Enhancer.associateOneToMany( EnhancedAttribute.children, this.children, this, "parent"); // iterates over this.children and call $$_hibernate_write_parent(this)
    }

    // to handle bi-direction assotiation we would need something like this
    // because only we know the actual types on the assotiation
    public static void $$_hibernate_target_association(EnhancedAttribute attribute, Object target, Object value) {
        switch ( ($$_hibernate_enhanced_attribute) attribute ) {
            case children:
                ( (Child) target ).$$_hibernate_write_parent( (Parent) value ); 
        }        
    }

}

// this enum would be the mapping contract to be passed around -- it's our vision of the attribute order and we may be able to explore further optimization with that
interface EnhancedAttributeEnumeration { 
    String name();
    int ordinal();
}

I am working on fork of this to show what I had in mind... But am including some specific in-line comments above

Oh, I guess we cannot do in-line comments :)

One random comment... I very very very much dislike the term "enum" in EnhancedAttributeEnumeration. Another fundamental point in defining something as an enum is the idea that the possibility set is finite and known a-priori. Neither of those 2 hold true here.