OOPortal OOPortal


Problem Analysis  «Prev  Next»
Lesson 8Basic object modeling
ObjectiveDefine Basic Object Modeling

Define Basic Object Modeling

Modeling as translation

Modeling is a process of abstracting a concept from one domain into a representation of it in another domain. Object modeling means translating words into class definitions.

Nouns to classes


Problem Domain Language
Earlier, you learned how to find classes by evaluating the nouns in everything you have gathered on the project up to this point:
  1. the problem statement,
  2. the data dictionary, and
  3. the use case model.
Each class was given a name and a purpose. Now place these classes on the class diagram. Begin to group them according to how they are used in the problem statement and use cases.

Class grouping according to how they are used in the problem statement.

Verbs to associations

How do objects of the classes in the diagram relate to one another? Look for verbs in the user vocabulary to uncover these relationships, or associations . Here are some questions to ask to help you find and name associations:
  1. What does one object do to the other object(s)?
  2. Does one object ask for help from another object(s)?
  3. Does one object send messages to, or notify, another object(s)?

Try to state the association using active verbs rather than passive verbs, for example, "holds" versus "is held by." Verb phrases are OK too, for example, "defines the use of".
In the course project, a customer selects a seat that he or she is interested in, and the system places that seat on hold for that customer. Name the association to reflect this fact much the same way you would write a sentence. Use the class names and add the verb:

Associations using class name in combination with a verb.