Structural Modeling

Introduction A Structural model is a formal way of representating the objects that are used and created by a business system One of the primary purposes of the structural model is to create a vocabulary that can be used by analyst and the user

Slide 3 Classes Templates for creating instances or objects Concrete Abstract Classes represent real world thing. Typical examples include: Application domain, user interface, data structure, file structure, operating environment, document, and multimedia classes

Slide 4 Attributes & Operations Attributes Units of information relevant to the description of the class Only attributes important to the task should be included Operations (Methods) Action that instances/objects can take Focus on relevant problem-specific operations (at this point)

Slide 5 Relationships Generalization Enables inheritance of attributes and operations. Generalization is represented with a-kind-of relationship Example: we say an employee is a-kind-of-person Aggregation Relates parts to wholes Aggregation represents: a-part-of, a-member-of, contained-in, related-to, and associated-with Association Other relationships that do not neatly fit into generalization (a-kind- of) or aggregation (a-part-of)

Slide 6 Your Turn What classes, attributes, and operations that would be required to describe the process of registration for campus housing?

Slide 7 Responsibilities and Collaborations Responsibilities Knowing responsibilities are those things that an instance of a class must be capable of knowing An instance typically knows the values of its attributes and its relationships Doing responsibilities are those things that an instance of a class must be capable of doing. An instance of a class can execute its operations, or it can request a second instance Collaboration Objects working together to service a request

Class Diagram Syntaks

Slide 9 A CRC Card Front: Class name:ID:Type: Description: Responsibilities:Collaborators: Back: Attributes: Relationships: Generalization (a-kind-of): Aggregation (has-parts): Other Associations:

A Class Represents a kind of person, place, or thing about which the system will need to capture and store information Has a name typed in bold and centered in its top compartment Has a list of attributes in its middle compartment Has a list of operations int its bottom compartment Does not exlicitly show operations that are available to all classes

An Attribute Represents properties that describe the state of an object Can be derived from other attributes, shown by placing a slash before the attribute’s name

Object identification Textual Analysis is an analysist of the text in the use-case description Brainstorming: process of set of individuals sitting around table and suggesting potential classes that could be useful for problem under consideration Common Object List is simply a list of objects common to business domain of system Pattern is a simply a useful group of collaborating classes that provide a solution to a commonly occuring problem

An Operation Represents the actions or functions that a class can perform Can be classified as a contructor, query, or update operation Includes parentheses that may contain paremeters of information needed to perform the operation

An Association Represents a relationship between multiple classes or a class and itself Is labeled using a verb phrase or a role name, whichecer better represents the relationship Can exist between one or more classess Contains multiplicity symbols, which represent the minimum and maximum times a class instance can be associated with the related class instance

A generalization Represents a-kind-of relationship between multiple classes

An Aggregation Represents a logical a-part-of relationship between multiple classes or a class itself Is a special form of an association

A composition Represents a physical a-part-of relationship between multiple classes or a class itself Is a special form of an association