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Unformatted text preview: 1 OBJECT-ORIENTED DESIGN/UNIFIED MODELING LANGUAGE (OOD/UML) REFERENCE (Ver 2.6) GENERAL FUNDAMENTAL CONCEPTS OF OBJECT ORIENTATION: Abstraction capture the essential, shared characteristics of an entity or group of entities Encapsulation conceal information that does not need to be exposed to an outside entity; bundle related information and functionality within an entity Generalization/Inheritance define elements such as Classes whose characteristics apply to multiple more specialized elements; child elements inherit the characteristics of the parent Interfaces clearly define interactions among entities and with the external environment; allow entities to interact by exchanging messages or other information across controlled boundaries Polymorphism hide details of implementation behind an interface; allow the same service invocation to yield different results depending on circumstances (e.g., the data type of a passed parameter) Modularity decompose complexity to enable understanding; localize effects of changes Hierarchy rank or order abstractions to capture common and unique features among entities DEALING WITH COMPLEXITY USING OOD: Abstraction focuses on the most important aspects of complex entities Facilitates decomposition inherently links information and users with their operations and responsibilities; objects correspond to real-world entities that have defined state and behavior (data and functions) Interface definition is inherent and natural; captures real-world interactions of a system Polymorphism allows tailored functionality w/ common interfaces Facilitates open, loosely coupled, service-oriented, component-based plug n play architectures Facilitates localization and confinement of the effects of design changes or system failures Inheritance minimizes the difficulty of handling variations among related information and actors Facilitates understanding of system states and transitions via the attributes and associations of objects CLASSES AND OBJECTS An Object is a basic entity of a system, providing an identifying label and encapsulating the information and operations associated with that entity; it is the physical entity that can hold information, perform functions and provide services to other Objects or external entities An Object is the instantiation of a Class; the Class abstracts the shared characteristics of its Objects An Association between Classes represents the ability to exchange messages and to request and deliver services; a Link is a semantic relationship between Objects and the instantiation of an Association Class and Object Diagrams capture the identity and interactions of Classes and Objects UML COMMON ELEMENTS 1 0..* Association Link 1 * Class Diagram Class Diagram * * * * * * 1..* 1..* * * * Class Class Package Model Model Element Visual Element Element 1 0..1 0..* 0..* 0..1 0..* 1..*1....
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- Summer '10