Structural Modelling and Class Diagrams

Flashcards on System Analysis and Design focusing on Structural Modelling, Object-Oriented concepts, and Class Diagrams, based on lecture notes.

Class

A UML diagram element that represents types of existing objects within a system, characterized by a name, attributes, and operations.

Attributes

Characteristics of a class that describe the data it holds.

Operations

Activities that a class can perform, defining its behavior.

Relationships

Connections between classes, indicating their relationships and how they interact.

Generalization

A type of relationship indicating that one class is a specialized form of another (a 'is a' relationship).

Aggregation

A type of relationship indicating that one class is a part of another (a 'has a' relationship).

Association

A relationship between classes that doesn't fit neatly into generalization or aggregation.

Multiplicity

Indicates how many instances of one class are related to another class.

Generalization

Denotes inheritance, where a subclass inherits properties and operations from a superclass.

Aggregation

Denotes a 'part-of' relationship, where one class is a component of another.

Composition

A special type of aggregation where the 'part' class cannot exist independently of the whole.

Self-Relationship

A relationship where a class is related to itself.

Structural Modelling

Identifying classes and objects from the problem domain and modeling the system’s structure.

Brainstorming

Creating an initial list by people offering ideas, of classes or objects, attributes, operations and relationships.

Common Objects List

A list of objects commonly found in business domains like physical things, users, events, interactions, places, organisations and catalogues.

Textual analysis of use-case descriptions

A way to create a rough first cut to provide an object list, like physical things, roles, events, from nouns, attributes and verbs.

Patterns

A useful group of collaborating classes that provide a solution to a commonly occurring problem.

CRC Cards

A technique using index cards to document Classes Responsibilities and Collaborations.

Responsibilities

What a class must do, manifested later as operations.

Collaboration

Other classes that are necessary to perform a responsibility.

Operation balance

An activity in an activity diagram should be related to one or more operations on a class diagram.

Messaging

Methods are called from within methods of other objects of the same or different classes.

Information Hiding

Ensures data/operation security with different access levels.

Public

A public attribute/methods is accessible from anywhere.

Private

A private attribute/method is only accessible within the class

Abstract Classes

Classes that cannot be directly instantiated.