The purpose of this section is to describe how policy templates can be defined. This provides a very important advantage – the ability to define standard templates, or specifications, that can be used to manage different types of managed entities. <br/>Note that there is no PolicySpecification class, since the Policy class is used to define common attributes and relationships that all Policy entities inherit.<br/>The main purpose of all entities in the PolicySpecification ABE, from the business point-of-view, is to provide a standardized structure of the entity that the Spec refers to.<br/>PolicyEvents have invariant as well as instance-specific characteristics and behavior. This gives rise to the concept of a PolicyEventSpec, which is shown in Figure below.<br/>A PolicyEventSpec is an abstract base class that is used to define the invariant characteristics and behavior (attributes, methods, constraints, and relationships) of a PolicyEvent. The composite pattern is used to define stand-alone and aggregated PolicyEventSpecs.<br/>
