Object Oriented Design

OOD

OOD characteristics - I

• conceptual compatibility with OOA

• notational consistency with OOA

• clean traceability of OOA results

• direct inclusion of OOA results

=> avoids the classical, conceptual “gap” between Analysis and Design

OOD regards

the OOA model as a problem-oriented

“Miniworld”

that needs to be supported and organized

by a computer-based system.

OOD characteristics - II

• OOD extends and refines OOA results

• OOD bridges the gap to the available infrastructure

• OOD is very much about reuse of– objects, – patterns, – and whole architectures

Object-Oriented DesignInfluence Factors & Relations

OOD

OOA Model

Architectures

OOD Model

Patterns

Infrastructure

OOA

Process

The Levels of the OOD Process -

High-Level Design• extend the OOA Model [Coad/Yourdon]

– include “domain components” in the model• acknowledge that we develop a computer-based

system

• include human interface, data management, communications and control aspects (task mgmt)

– decide on a general system architecture• how to organize the above aspects into a well specified

structure (and behavior)

• reuse existing patterns and solutions

The Levels of the OOD Process - Detailed Design

• refine and

• map the OOA Model to the infrastructure– detailed algorithms and datastructures– implementation of OO structures– implementation of states and transitions– optimization– maximize reuse– exception handling– etc.

The OOD “Co-Design” ProcessMatrix of Domain Components and Levels

TMCHIC PDC DMC

high-levelDesign

detailedDesign

Miniworld

extend

refine &map

Object Oriented Design means

to navigate the domain/level matrix

with the purpose

to complete all associated tasks

in a meaningful sequence.

OOD and SW-Architectures

• A clear general architectural concept and a good matching infrastructure will simplify.

• Detailed design is a means to work around mismatches between infrastructure and (architectural) high-level design.

=> specify widely applicable, generic architectures

=> develop compatible, stable infrastructures

OOD Deliverables - I

• extended Static Objectmodel – Coad & Yourdon:

• Problem Domain Component (PDC)

• Human Interaction Component (HIC)

• Task Management Component (TMC)

• Data Management Component (DMC)

• on the level of high-level (and detailed) design

OOD Deliverables - II

• completed & extended Scenarios – extend old scenarios across domains

• reflect the chosen architecture’s dynamics

• build links between domain components

– add new scenarios to accommodate internal organization

• e.g. data backup, rollback, load/save

• on the level of high-level design as diagram

• on the level of detailed design in the dictionary• diagram as necessary

Scenarios

TMCHIC PDC DMC

high-levelDesign

detailedDesign

extend

refine &map

OOD Deliverables - III

• Object Dictionary – document & specify the added domain components

• very much like during analysis: objects, structures, ...

• for high-level design

– map and refine existing specifications• translate structures, STDs, ...

• map to existing patterns and objects

• document optimizations

• for detailed design

• As in OOA it holds for OOD: Static Model and Scenarios are documented as graphical Views of the more complete Object Dictionary.

The OOAD Documentation

TMCHIC PDC DMC

high-levelDesign

detailedDesign

Miniworld

Dictionary

Scenarios

StaticModel

Dictionary

Scenarios

StaticModel