RLS — Simplication of Error Type (Figure 6):

Error Type classes are defined for each Error Information class in Figure 6. However it seems to be unnatural and too complex to define such classes just for discriminating error types. Implementation also is hard.

More natural way would be defining one class that is an enumeration of various error types like the case of RoLo Attribute SingleValue in Figure 21.

Instead of the way suggested in the summary, we decided to use only a single
class for describing RoLo error types and use hierarchy of RoLo error type
instances to represent the relationships instead of the class hierarchy in the
original specification. By this change, we can decrease the complexity of defining
classes that is never instantiated while preserving the original functionality and
extendibility.