Common Object-Oriented Terms

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Abstract class

Back 1

A class that does not have objects instantiated from it

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Abstraction

Back 2

The identification of the essential characteristics of an item

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Aggregation

Back 3

Represents “is part of” or “contains” relationships between two classes or components

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Aggregation hierarchy

Back 4

A set of classes that are related through aggregation

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Association

Back 5

Objects are related (associated) to other objects

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Attribute

Back 6

Something that a class knows (data/information)

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Class

Back 7

A software abstraction of similar objects, a template from which objects are created

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Cohesion

Back 8

The degree of relatedness of an encapsulated unit (such as a component or a class)

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Collaboration

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Classes work together (collaborate) to fulfill their responsibilities

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Composition

Back 10

A strong form of aggregation in which the “whole” is completely responsible for its parts and each “part” object is only associated to the one “whole” object

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Concrete class

Back 11

A class that has objects instantiated from it

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Coupling

Back 12

The degree of dependence between two items

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Encapsulation

Back 13

The grouping of related concepts into one item, such as a class or component

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Information hiding

Back 14

The restriction of external access to attributes

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Inheritance

Back 15

Represents “is a”, “is like”, and “is kind of” relationships. When class “B” inherits from class “A” it automatically has all of the attributes and operations that “A” implements (or inherits from other classes)

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Inheritance hierarchy

Back 16

A set of classes that are related through inheritance

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Instance

Back 17

An object is an instance of a class

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Instantiate

Back 18

We instantiate (create) objects from classes

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Interface

Back 19

The definition of a collection of one or more operation signatures that defines a cohesive set of behaviors

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Message

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A message is either a request for information or a request to perform an action

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Messaging

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In order to collaborate, classes send messages to each other

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Multiple inheritance

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When a class directly inherits from more than one class

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Multiplicity

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A UML concept combining the data modeling concepts of cardinality (how many) and optionality.

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Object

Back 24

A person, place, thing, event, concept, screen, or report

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Object space

Back 25

Main memory + all available storage space on the network, including persistent storage such as a relational database

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Operation

Back 26

Something a class does (similar to a function in structured programming)

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Override

Back 27

Sometimes you need to override (redefine) attributes and/or methods in subclasses

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Pattern

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A reusable solution to a common problem taking relevant forces into account

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Persistence

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The issue of how objects are permanently stored

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Persistent object

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An object that is saved to permanent storage

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Polymorphism

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Different objects can respond to the same message in different ways, enable objects to interact with one another without knowing their exact type

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Single inheritance

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When a class directly inherits from only one class

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Stereotype

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Denotes a common usage of a modeling element

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Subclass

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If class “B” inherits from class “A,” we say that “B” is a subclass of “A”

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Superclass

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If class “B” inherits from class “A,” we say that “A” is a superclass of “B”

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Transient object

Back 36

An object that is not saved to permanent storage