UML Diagrams Class Diagram Class diagrams Class diagrams

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UML Diagrams Class Diagram

UML Diagrams Class Diagram

Class diagrams � Class diagrams show the classes of the system, their interrelationships (including

Class diagrams � Class diagrams show the classes of the system, their interrelationships (including inheritance, aggregation, and association), and the operations and attributes of the classes. � Class diagrams are used for a wide variety of purposes, including both conceptual/domain modeling and detailed design modeling.

Class diagrams elements 1. 2. 3. 4. 5. 6. 7. Class Attribute Methods (Operations)

Class diagrams elements 1. 2. 3. 4. 5. 6. 7. Class Attribute Methods (Operations) Generalization Association Multiplicity Aggregation

1. Class An object is any person, place, thing, concept, event, screen, or report

1. Class An object is any person, place, thing, concept, event, screen, or report applicable to your system. � A class is a representation of an object and, in many ways, it is simply a template from which objects are created. � Although thousands of students attend the university, you would only model one class, called Student, which would represent the entire collection of students. �

2. Attribute � An attribute of a class represents a characteristic of a class.

2. Attribute � An attribute of a class represents a characteristic of a class. � Characteristics of interest of a passenger, for example, are name and age.

3. Methods (Operations) � � � � The operations describe how a class can

3. Methods (Operations) � � � � The operations describe how a class can interact with data. All classes have different access levels depending on the access modifier (visibility). Here are the following access levels with their corresponding symbols: Public (+) Private (-) Protected (#) Static (underlined)

4. Generalization � Terms such as superclass, subclass, or inheritance come to mind when

4. Generalization � Terms such as superclass, subclass, or inheritance come to mind when thinking about the object-oriented approach. � Generalization is the process of extracting shared characteristics from two or more classes, and combining them into a generalized superclass. Shared characteristics can be attributes, associations, or methods.

4. Generalization

4. Generalization

5. Association � An association represents a relationship between two classes. � An association

5. Association � An association represents a relationship between two classes. � An association indicates that objects of one class have a relationship with objects of another class, in which this connection has a specifically defined meaning.

6. Multiplicity �A multiplicity allows for statements about the number of objects that are

6. Multiplicity �A multiplicity allows for statements about the number of objects that are involved in an association.

7. Aggregation � An aggregation is a special case of an association meaning "consists

7. Aggregation � An aggregation is a special case of an association meaning "consists of“

Examples

Examples