Class and Object Diagrams Quiz

Questions and Answers

What shape represents an n-ary association in UML?

Hollow diamond (correct)

Solid triangle

Hollow circle

Solid square

Which best describes shared aggregation in UML?

Parts exist independently of the whole. (correct)

Parts are intrinsic to the whole.

Parts can only belong to one whole.

Parts are destroyed when the whole is destroyed.

What does a composition indicate in UML?

A part can only be contained in one composite object at a time. (correct)

Parts have a weak dependency on the whole.

A part can exist independently from the whole.

Parts can belong to multiple wholes.

What is the purpose of a generalization relationship?

To emphasize commonalities among classes. Signup and view all the answers

Which statement about subclasses in a generalization relationship is true?

Every instance of a subclass is also an instance of its superclass. Signup and view all the answers

How is an association represented in UML?

By a solid line Signup and view all the answers

What distinguishes composition from shared aggregation?

Parts in composition cannot exist without the whole. Signup and view all the answers

Which term describes the transfer of characteristics from a superclass to its subclasses?

Generalization Signup and view all the answers

In UML, what does the term 'n-ary association' refer to?

An association involving three or more partners. Signup and view all the answers

What is the role of a professor in the context described?

To facilitate lectures without access to student characteristics. Signup and view all the answers

Study Notes

Class and Object Diagrams

Class diagrams model the static structure of a system, outlining elements and their relationships.
Used throughout different software development phases, adapting detail level as the project progresses.
Early phases focus on a conceptual view, facilitating vocabulary definition for the system.
Object diagrams represent actual instances of objects at a particular time, reflecting data in classes.

Class Representation

A class is depicted as a rectangle divided into compartments:
- First compartment: Class name.
- Second compartment: Class attributes (with types, e.g., integer, string).
- Third compartment: Operations (methods) of the class.
Attributes may include a name, type, and optional default value (e.g., = Default).
Operations are executed when called; their signatures show operation name and parameters.

Access Control and Visibility

Visibility defines access permissions for attributes and operations:
- Private: Accessible only by the object itself.
- Public: Accessible by any object.
- Protected: Accessible by the class and its subclasses.
- Package: Accessible by classes within the same package only.
Information hiding is used to protect the internal state of objects.

Multiplicity in Relationships

Describes how many instances of one class relate to instances of another:
- One-to-One: Each entity must have a corresponding single entity (e.g., students and ID cards).
- One-to-Many: A single entity can relate to multiple entities (e.g., students and courses).
- Many-to-Many: Multiple entities can relate to multiple entities (e.g., students and classes).

Associations and Relationships

Binary associations connect instances of two classes, represented by solid lines.
Relationships can be labeled for clarity, with navigability indicating access to partner objects' attributes.
N-ary associations involve more than two classes, depicted with a hollow diamond at the center.

Aggregation and Composition

Aggregation indicates that instances of one class are part of another; two types exist:
- Shared Aggregation: Parts exist independently of the whole.
- Composition: Parts are strictly bound to the whole object.

Generalization and Inheritance

Generalization identifies common characteristics among classes, reducing redundancy.
Inheritance allows subclasses to adopt attributes and behaviors of superclasses, establishing a hierarchical relationship.
Each subclass is also an instance of its superclass, embodying shared characteristics.

Description

Test your understanding of class and object diagrams used in software development. This quiz will cover the static structure of systems, class representation, and access control mechanisms. Ideal for students and professionals looking to reinforce their knowledge in software engineering concepts.