Object-Oriented Software Engineering Chapter 5

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Questions and Answers

What do analysis models in object-oriented software engineering primarily represent?

Detailed implementation specifications

Actual software components and classes

Non-functional requirements

User-level concepts and abstractions (correct)

Which of the following should not be included in an analysis model?

Specific software components like Database (correct)

Use cases analyzing user scenarios

User interactions and requirements

High-level abstractions of user needs

In the context of object-oriented software engineering, what is a primary goal of requirements elicitation?

To create software documentation

To validate existing software features

To define the technical architecture

To uncover user needs and expectations (correct)

What type of diagrams are used to represent user-level interactions in object-oriented analysis?

Sequence diagrams Signup and view all the answers

Which statement accurately describes the purpose of the dynamic model?

It details the behavior of the system over time Signup and view all the answers

What is the main goal of the object modeling process?

To find important abstractions Signup and view all the answers

In class identification during object modeling, which assumption is NOT typically made?

Classes are always found intuitively without analysis. Signup and view all the answers

What defines the system boundary in the context of class identification?

Actors that interact with the system Signup and view all the answers

What activity identifies abstract concepts from lower-level ones in object-oriented modeling?

Generalization Signup and view all the answers

What is a significant challenge faced during class identification?

Determining the system's purpose and boundaries Signup and view all the answers

Which object type is responsible for handling procedures or control logic in a system?

Control Object Signup and view all the answers

What is the primary purpose of dividing objects into types such as Entity, Control, and Boundary?

To better manage changes in the system Signup and view all the answers

According to Abbott’s Technique, which of the following should be used to analyze use cases for identifying objects?

Noun-verb analysis Signup and view all the answers

Which of the following is NOT a type of object discussed?

Participant Object Signup and view all the answers

Which statement correctly reflects the communication capability of Controllers?

Controllers can communicate with Entity Objects and other Controllers. Signup and view all the answers

What aspect of the system is likely to change more frequently than the Entity Objects?

User interface Signup and view all the answers

In the context of Smalltalk’s MVC, what does the 'Model' refer to?

Entity Object Signup and view all the answers

What characterizes a Low-Priority Incident?

It does not need to be addressed if resources are needed for higher-priority incidents. Signup and view all the answers

Which type of object represents persistent information tracked by the system?

Entity Objects Signup and view all the answers

What is the primary role of Control Objects in an object-oriented system?

To implement logic that manages interactions between boundary and entity objects. Signup and view all the answers

Which of the following is an example of a Boundary Object?

A user interface screen Signup and view all the answers

How many types of Incidents are defined in the content?

Three types Signup and view all the answers

What is the purpose of using UML Stereotype mechanism in modeling?

To distinguish between different types of objects in a model. Signup and view all the answers

An Emergency Incident requires:

Immediate handling by a single agency. Signup and view all the answers

Which of these roles does NOT belong to Entity Objects?

Representing system users. Signup and view all the answers

Study Notes

Object-Oriented Software Engineering (OOSE)

OOSE involves using UML, patterns, and Java.
Chapter 5 focuses on analysis and object modelling.

Ambiguity

Figure 5-1 illustrates ambiguity.
It highlights the need for clear definition of system boundaries and identification of objects.

OOSE Development Activities and Products

An overview of OOSE development activities and their products is presented graphically.
Activities include problem statement, requirements elicitation, analysis, functional modeling, dynamic modeling, analysis object model, and system design.
Products include use case diagrams, sequence diagrams, state diagrams, and activity diagrams.

Analysis

Analysis models represent user-level concepts, not software classes.
Models are high-level abstractions that are later realized in more detail for software.
Specific domain concepts and software classes are identified and distinguished.
Domain concepts should be represented in analysis object model.
Software classes that should NOT be represented in analysis model are defined.

Activities During Object Modeling

Main goal of object modeling is to find important abstractions (things and actions).
Steps include identifying classes and their attributes, methods, and associations between classes.
The order of activities is secondary; often iterative and revised based on analysis.

Class Identification

Crucial to Object-Oriented (OO) modeling.
Identifying important entities in a system.
Two basic assumptions:
- Finding classes for new systems (Forward Engineering).
- Identifying classes in existing systems (Reverse Engineering).
Class identification is a complex issue because it depends on context of a system, especially on what the system boundaries are. Understanding how end users view and use a system is crucial.
Identifying the purpose of a system using scenarios and use cases leads to Functional models.

Generalization vs. Specialization

Generalization identifies abstract concepts from lower-level ones.
Specialization identifies more specific concepts from a high-level one.
Useful for creating a hierarchy/taxonomy of abstractions to improve understanding.

Class Hierarchy

Example of a UML generalization hierarchy.
Shows relationships between generalized and specialized classes.

Different Object Types

Entity Objects represent persistent information.
Boundary Objects represent interactions with users.
Control Objects mediate between boundaries and entities, implementing logic.

2BWatch Modeling Example

Demonstrates how to distinguish between different object types using UML stereotypes.
Different object types assigned to entities (e.g year, month), control objects (e.g., ChangeDate), and boundary objects (e.g., Button, LCD).

UML Stereotypes

UML provides stereotypes mechanism.
Provides a way to name object types, methods and attributes with symbols, making models easy to understand.
Notation: <>name of element (e.g., <<Entity>>Year).

UML as an Extensible Language

UML is extensible.
Stereotypes can be used for classifying method behavior (e.g., <>).
Icons can be used to represent stereotypes.

Icons for Stereotypes

Using icons improves the visual aspects of class diagrams.
Icons are displayed next to or above an element name to identify the stereotype.

Pros and Cons of Stereotype Graphics

Advantages: Improve diagrams and class diagrams by using graphics/icons.
Disadvantages: Graphics/icons can be difficult to grasp for developers who aren't already familiar with them.

Communication Among Objects

Defines rules for communication between objects.
Actors can talk to boundary objects.
Boundaries objects can talk to controllers.
Entity objects communicate with controllers.
Controllers interact with boundaries, entities, and other controllers, not actors.

Benefit of Object Types

Object types allow changes/adaptations to systems, enhancing system resilience and making it easy to change features.

Finding Participating Objects in Use Cases

Use cases are used to discover participating objects.
Use a textual analysis approach to identify objects and classes.
Include real-world entities, procedures that are kept in models, and interface artifacts (examples provided).

Mapping Parts of Speech to Model Components

Mapping techniques help identify the elements in a model.
Example using Abbot's technique to map words to model components (e.g., "Buy," "toy," "is-a").

Generating a Class Diagram from Flow of Events

Example demonstrating how to create a Class Diagram from a use case/scenario flow of events.

Ways to Find Objects

Various ways, including flow of events in use cases, problem statements, end users/experts knowledge, and general knowledge.

Order of Activities for Object Identification

Sequence of steps for identifying objects, including formulating scenarios, eliciting use cases through expert input(s), and analyzing events with the help of a textual analysis technique (e.g., Abbot's).

Steps in Generating Class Diagrams

Steps involved in creating class diagrams: identifying classes, their attributes/operations, and relationships (associations, multiplicities, inheritance).

Who Uses Class Diagrams?

Users, including domain experts, identify static properties of a system, helping in requirements/analysis (e.g., application domain)
Developers identify and use diagrams to create software systems during analysis, design , object design and implementation stages.

Who Does Not Use Class Diagrams?

Clients and end users may not be interested in detailed class diagrams. They are more focused on project management, and application functionality.

Developers' Different Views on Class Diagrams

Developers' perspectives on class diagrams vary based on their specific role within the development process.
Roles include analyst, system designer, object designer, and implementor/development engineer.

The View of the Analyst

The analyst focuses on the application domain's classes and operations and uses inheritance for relationships.
Analyst is not interested in solution domain operations or classes.

The View of the Designer

Focuses on the solution and the interfaces of subsystems, using references (pointers) between classes.

Goals of the Designer

Goals include ensuring system usability through interface design, and maintainability/reusability, as well as identifying opportunities/potential for reuse of parts within existing or potential software systems (e.g., class libraries, frameworks, design patterns).

The View of the Implementor / Developer Engineer

Roles include:
- Implementing methods/interfaces of classes using programming languages.
- Considering appropriate data structures and algorithms for attributes and operations.
- Extending (or adapting classes for) new or changed situations.
- Class users focus on how classes operate without worrying about individual components.

Why Distinguish Users of Class Diagrams?

Models may not immediately distinguish application and solution classes.
Distinguishing these is a preferred approach but not always practiced in all design settings.
Avoiding solution classes in analysis models is preferred.

Analysis Model vs. Object Design Model

Analysis model is created during analysis phase; focuses on application domain classes; main users include stakeholders and analysts.
Object design model (or Specification model) is created during object design phase; encompasses application and solution domain classes; and is created by/for developers, including class specifiers and extenders.

Summary

System modeling includes Functional + object + dynamic modeling.
Object modeling is a central activity in the development process, including identifying classes and applying rules for creating relationships between them (e.g., Abbot's technique).
Analysis/UML activity diagrams present development steps, from defining use cases, objects, interactions, and associations and attributes to consolidating/reviewing the model.

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Description

This quiz covers Chapter 5 of Object-Oriented Software Engineering, which focuses on analysis and object modeling. It explores the importance of clear definitions, OOSE development activities, and the products involved in the analysis process. Test your knowledge on UML, modeling, and the distinctions between domain concepts and software classes.