Entity Type Enhancement

In TG extensive use is made of dynamic entity type enhancements - generated Java classes that enhance entity types they are based on in various ways.

For example:

• Instrumented entity types - enhanced with interception of property setters, which enables property validators and definers.
• Criteria entity types - enhanced with crit-only properites; core component of entity centres.

Entity type enhancements can be categorised into 2 groups:

1. Structural enhancement - the structure of an enhanced type differs from that of its base type. E.g., new properties are added.
   • Criteria entity types
   • Entity types with custom calculated properties
2. Non-structural enhancement - the opposite of structural enhancement.
   • Instrumented entity types
   • Proxied entity types

Structure of an entity type is defined to consist of the following:

• Entity nature
• Properties
• Type-level annotations that affect entity nature or its properties (e.g., @KeyType determines the type of property key).

This categorisation is especially useful in application to computations that operate on the structure of an entity type and use caching: non-structurally enhanced entity types can be treated as their base types.