CPSC 606 : Software Engineering

1
CBD

• CPSC 606 Software Engineering

- Component Based Development -
Presented ByJongyoon Choi
2
Table of contents

• Definition of Component
• Types of Component
• Characteristics of Component
• Standards for Component
• Interface
• Comparison with OOAD
• Catalysis Method

3
Definition of Component

• The definition of component is different between
  people

Definitions

• A component is an independently deliverable
  package of operations. - Texas Instruments
  Literature
• A component is just a physical packaging of a
  society of classes. - Grady Booch
• A replaceable unit of development work which
  encapsulates design decisions and which will be
  composed with other components as part of a
  larger unit. - Desmond DSouza, in Catalysis
• A runtime software component is a dynamically
  bindable package of one or more programs managed
  as a unit and accessed through documented
  interfaces that can be discovered at runtime. -
  Gartner Group

Common features

• identity, reusable, published interface

4
Types of Component1

• We can classify components with broad definition.

Class Library

• The lowest abstraction level
• Very similar to programming code.
• Not enough separation of interface and
  implementation
• It requires high level skill of object skill

Encapsulated Component

• The most common one
• Interface and implementation is separated well
• Higher abstraction level than class library
• Low required skill level and high productivity

5
Types of Component2
Software Framework

• Reusable as a group Set of Items
• User can customize by own needs
• EX) MFC(Microsoft Foundation Class) by Microsoft

Pre-built Application

• It is and application itself
• The smallest level of user coding
• It constructs whole domain as function of
  Pre-built Application
• EX) SAP R3

6
Characteristics of Component

• The component is an independent module

Essential

• Identifiable
• Traceable Replaceable
• Accessed only via interface.
• Services Offered through interfaces should not
  Change
• Accurately Documented Service)

Optional

• Physical Implementation is Hidden
• Independent
• Encapsulated
• Reuse of Services is not constrained by Physical
  Implementation)
• Platform Independent Reuse
• Can be Reused Dynamically
• Offer a Generic Service
• Specialized only via Designated Plug Points
• Certified and Authenticated

Virtual Software Repository by Carnegie Melon
University
7
Standards for Component

• A component has several elements and should
  follow standard specification for interoperability

• Interface Set of operation signatures for
  invoking component service
• Implementation Actual implementation for the
  service
• Container Service provider for locating and
  getting component interface
• EX) CORBA 3.0, Enterprise JavaBeans, COM

8
Interface

• An interface is the core of component

One of the greatest challenges to component
software is designing Interfaces that are
reusable, adaptable, flexible and prepared for
the future
-Inside COM. Rogerson. Microsoft Press
Why important ?

• It connects client with component internal
  implementation
• We can use component if we know the Interface
• We can change component while keeping the
  Interface

How to define ?

• Described by IDL(Interface Definition Language)
• Interface is separated from the Implementation

9
Comparison with OOAD

• CBD and OOAD is not competitive

OOAD

• OOAD is concerned with creating objects
• Design of function inside the component
• OOAD is designing process for internal
  architecture

CBD

• CBD is concerned with making object work
  together
• Design of interface which exposed from component
• CBD is the modulation process to set entire
  specification

10
Catalysis Method1

• Designed by Desmond DSouza

11
Catalysis Method2
Essential Domain Modeling

• define the scope of the domain and make domain
  model

• Preparing a Domain Model

• Preparing a Business Type Model

create type collaboration diagram decompose all
actions to the operation level
12
Catalysis Method3
To-Be System Context Modeling

• Describe system functionality with interaction
  between domain type and interface

• Scope the system interface

• System context model

13
Catalysis Method4
Type Interface Definition

• Preparing an Interfaces Type Model

Decide data type Specify Business Type

• Defining Operation Specification

• Set operation signature
  regCreateConfirmationLetter(InOut
  RegRegistration, Out RegDetailsRegistration
  Details)
• Set pre-condition post-condition
• Pre-condition for regCreateConfirmationLetter
• RegRegistration exists, Reg.Letter Sent False
• Post -condition for regCreateConfirmationLetter
  Confirmation letter created, Reg.Letter Sent
  True, Reg.Confirmation not equal to Null

14
Catalysis Method5
Essential Domain Modeling

• Identifying a Component
• Assign interface to a component

Application User Interface Definition

• Paper Prototyping User Interface Prototype
• Software Prototyping Software Prototype Code
• Usability Testing user feedback

15
Summary

• CBD is promising but it is not easy to apply it

Advantage

• Management of Complexity
• Reduce Development Time
• Increased Productivity
• Improved Quality

Disadvantage

• Development of Components
• Lack of Components
• Component Maintenance Costs
• Reliability and Sensitivity to changes
• Unsatisfied Requirements
• Trust

16
References
Crnkovic, Ivica, Component-based Software
Engineering New Challenges in Software
Development, in 27th Int. Conf. Information
Technology Interfaces 2003, June 1-19, 2003,
Cavtat, Croatia. Desmond F. DSouza, Alan
Cameron Wills, Objects, Components, and
Frameworks with UML, Addison Wesley,
1998 Clemens Szyperski, Component Softeware
beyond object-oriented programming, Addison
Wesley, 1997 John Cheesman, John Daniels, UML
Components, Addison Wesley, 1998
1 2 3 4
17
Questions
1. What is the difference from OOAD ?
2. How can we handle customization ?
3. How can we connect to persistent storage ?
4. Using out side component is always good ?
5. Can we make system like Lego block ?
18
QA