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Object Oriented Implementation

This document discusses object-oriented implementation including model transformations, refactoring, forward and reverse engineering. It covers mapping concepts like associations to collections and contracts to exceptions. It also discusses optimizing object models and mapping models to persistent storage schemas.

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Pramod Parajuli

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0% found this document useful (0 votes)

56 views33 pages

Object Oriented Implementation

Uploaded by

Pramod Parajuli

We take content rights seriously. If you suspect this is your content, claim it here.

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Download as ODP, PDF, TXT or read online on Scribd

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OBJECT-ORIENTED

SOFTWARE ENGINEERING
UNIT 06 : Object Oriented Implementation

© 2018, PRAMOD PARAJULI

Disclaimer
These slides are part of teaching materials for Object Oriented
Software Engineering (OOSE). These slides do not cover all
aspect of learning OOSE, nor are these be taken as primary
source of information. As the core textbooks and reference
books for learning the subject has already been specified and
provided to the students, students are encouraged to learn
from the original sources.

Contents in these slides are copyrighted to the instructor and

authors of original texts where applicable.
OOSE UNIT 06 - Object Oriented Implementation
Reference:
Bruegge B., and Dutoit A. H. 2010, Object-oriented Software
Engineering using UML, Patterns and Java, 3rd ed., Prentice Hall
(Chapter 10)

OOSE UNIT 06 - Object Oriented Implementation

MAPPING CONCEPTS
 Model transformations
 Refactorings
 Forward engineering
 Reverse engineering

OOSE UNIT 06 - Object Oriented Implementation

MODEL TRANSFORMATION
Applied to object model and results in another object
model.

OOSE UNIT 06 - Object Oriented Implementation

REFACTORING
To improve source code readability or modifiability
without changing its behavior.

OOSE UNIT 06 - Object Oriented Implementation

FORWARD ENGINEERING

OOSE UNIT 06 - Object Oriented Implementation

REVERSE ENGINEERING
 Mapping source code elements back to a set of
model elements.
 CASE tools help build an approximate model.
 Approximate – because forward engineering may lose
information e.g. associations are turned into collections
of references.

OOSE UNIT 06 - Object Oriented Implementation

TRANSFORMATION PRINCIPLES
 Each transformation must address a single criteria.
 Each transformation must be local.
 Each transformation must be applied in isolation to
other changes.
 Each transformation must be followed by a
validation step.

OOSE UNIT 06 - Object Oriented Implementation

TRANSFORMATIONS
Transform models
 Optimising the object design models i.e. class models
 Mapping associations to collections
 Mapping operations contracts to exceptions
 Mapping the class model to a persistent storage schema

OOSE UNIT 06 - Object Oriented Implementation

OPTIMISING THE OBJECT DESIGN MODEL
Optimising access paths
 Repeated association traversals – frequent operations
between two objects through other objects must be simplified
by creating an association.
 “Many” associations – decrease search time by reducing the
“many” to “one”
 Misplaced attributes – reduce excessive modeling, calling vs.
hosting classes

OOSE UNIT 06 - Object Oriented Implementation

OPTIMISING THE OBJECT DESIGN MODEL
Collapsing objects

OOSE UNIT 06 - Object Oriented Implementation

OPTIMISING THE OBJECT DESIGN MODEL
Delaying
expensive
computations

OOSE UNIT 06 - Object Oriented Implementation

OPTIMISING THE OBJECT DESIGN MODEL
Caching the result of expensive computations
 If some values are repeatedly access after
computation, its better to keep them in cache.

OOSE UNIT 06 - Object Oriented Implementation

MAPPING ASSOCIATIONS TO COLLECTIONS

OOSE UNIT 06 - Object Oriented Implementation

MAPPING ASSOCIATIONS TO COLLECTIONS

OOSE UNIT 06 - Object Oriented Implementation

MAPPING ASSOCIATIONS TO COLLECTIONS

OOSE UNIT 06 - Object Oriented Implementation

MAPPING ASSOCIATIONS TO COLLECTIONS

OOSE UNIT 06 - Object Oriented Implementation

QUALIFIED ASSOCIATIONS

OOSE UNIT 06 - Object Oriented Implementation

ASSOCIATION CLASSES

OOSE UNIT 06 - Object Oriented Implementation

MAPPING CONTRACTS TO EXCEPTIONS
Contracts help in;
 Checking preconditions
 Checking postconditions
 Checking invariants
 Dealing with inheritance

OOSE UNIT 06 - Object Oriented Implementation

MAPPING CONTRACTS TO EXCEPTIONS
Example

OOSE UNIT 06 - Object Oriented Implementation

OOSE UNIT 06 - Object Oriented Implementation
OOSE UNIT 06 - Object Oriented Implementation
MAPPING CONTRACTS TO EXCEPTIONS