Starting Object-Oriented Analysis › Object Modeling with CA Gen

Object Modeling with CA Gen

The following table presents the vocabulary of object modeling methods with the equivalent or broadly equivalent terms from CA Gen.

Object modeling is an alternative technique for modeling an area of a business. It bears many similarities with the data/activity analysis approach, but it does differ in some important ways:

• Business entities and activities are integrated into a single model. This tighter integration of models produces a robust model early in the development process.
• Business entities are perceived to own and perform business activities. In fact, each aspect of the functionality of the business area should be regarded as owned by some business entity (usually called an object or instance). We call each discrete unit of functionality an operation of the business entity.
• In object modeling you document generic classes of business entities, rather than individual business entities. These classes continue to be termed entity types, although they are variously termed object types or classes or concepts in object modeling methods.
• In object models, entity types are perceived to be packages of functionality that maintain data about themselves. They also continue to correspond to types of things (tangible or intangible) that the business has to monitor. For example, the entity type Customer performs operations like Change Credit Rating and Offer Discount. It also keeps data about itself such as Name, Address, Payment Statistics, and Sales Statistics. This data can only be accessed through the operation of the business entity.
• An operation of an entity may need information about entities of other types, or may need to update the data of other types. For example, when an Order is changed, the credit rating of the Customer may need to be checked and the Customer statistics may need to be changed. An operation of one entity often needs to use the operations of other entities. The Change Order operation is not allowed to directly manipulate data but must be done under CA Gen control using CA Gen operations.
• Each entity is regarded as a black box of functionality: each entity encapsulates its data. This style of modeling ensures entity types are relatively independent, which encourages reuse and promotes the maintainability and software quality of applications based on object models.
• To summarize: an object model describes the problem domain as a mesh of intercommunication, functioning, black-box entity types, instead of by a cross-related, entity and activity models.

The following illustration should help you understand features that enable entity types to be regarded as object types (or classes) and hence to be used as building blocks within objects models.