The hierarchy of property descriptor classes mirrors the hierarchy of non-typed data element classes. In the same way that DataElement is the parent for all data elements, AbstractPropertyDescriptor is the parent for all property descriptors and implements the PropertyDescription interface. Property descriptors for simple types inherit directly from this abstract super class in a similar way that data field classes inherit directly from DataElement. The toolkit provides property descriptors for basic types such as String, Integer, Float and Date (StringDescriptor, IntegerDescriptor, FloatDescriptor, and DateDescriptor). These classes are sample implementations of descriptors for simple types. Depending on application requirements, you may need to extend them or replace them with another implementation.

Compound property descriptors describe business objects that inherit from DataCollection (that is, from either KeyedCollection or IndexedCollection) to provide a way of capturing the more complex behavior and structure of the complex types. The toolkit provides the KCollPropertyDescriptor and ICollPropertyDescriptor, subclasses of AbstractPropertyDescriptor to describe compound business objects. The following diagram shows the relationships between the classes in the property descriptor hierarchy: