Object Oriented Analysis and Design 1

Chapter 9 From Design to Implementation Implementation Model Forward, Reverse, and Round-Trip

Engineering Mapping Designs to Code Test-Driven Development

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Implementation Model

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9.1 Implementation Model Concept of Component Component Diagram Concept of Node Deployment Diagram

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Concept of Component a component is a physical and replaceable

part of a system that conforms to and provides the realization of a set of interfaces.

Graphically, a component is rendered as a rectangle with tabs, usually including only its name.

Login.dll

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Component Diagram

component.javaImageObserver

image.java

A component diagram shows the organizations and dependencies among software components, including source code components, binary code components, and executable components.

Component diagrams contain: Component packages. Components Interfaces Dependency relationships

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Component Diagram Captures the physical structure of the

implementation Built as part of architectural specification Purpose

Organize source code Construct an executable release Specify a physical database

Developed by architects and programmers

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Component Diagram - Example

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Component Diagram - Example

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What is Node? a node is a physical element that exists at run time

and represents a computational resource, generally having at least some memory and, often, processing capability.

A set of components may reside on a node and may also migrate from node to node.

Graphically, a node is rendered as a cube, usually including only its name.

Node #1

<<Node>>

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What Is a Connection? A connection represents a:

Communication mechanism

• Physical medium• Software protocol

Server<<Processor>>

<<RS-232>>

<<10-T Ethernet>>

Connection

Console

Kiosk

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Deployment Diagram A deployment diagram is a diagram that shows

the configuration of run time processing nodes and the components that live on them.

Captures the topology of a system’s hardware Built as part of architectural specification Purpose

Specify the distribution of components Identify performance bottlenecks

Developed by architects, networking engineers, and system engineers

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Deployment Diagram - Example

Course Catalog

<<legacy>>

<<Campus LAN>> <<Campus LAN>>

<<Campus LAN>><<Campus LAN>>

Registration Server

Desktop PC Desktop PC

Billing System

<<legacy>>

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Deployment Diagram -Example

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Deployment Diagram -Example

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9.2 Forward, Reverse, and Round-Trip Engineering Forward Engineering Reverse Engineering Round-Trip Engineering

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Forward Engineering Forward engineering means the generation of code

from UML diagrams Many of the tools can only do the static models:

They can generate class diagrams from code, but can't generate interaction diagrams.

For forward engineering, they can generate the basic (e.g., Java) class definition from a class diagram, but not the method bodies from interaction diagrams.

DemoGenerate

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Reverse Engineering Reverse engineering means generation of UML

diagrams from code Demo

Re-Engineer

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Round-Trip Engineering Round-trip engineering closes the loop

the tool supports generation in either direction and can synchronize between UML diagrams and code, ideally automatically and immediately as either is changed.

Demo

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9.3 Mapping Designs to Code Creating Class Definitions from Class Diagram Creating Methods from Interaction Diagrams Collection Classes in Code

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Creating Class Definitions from Class Diagram Defining a Class with Method Signatures and

Attributes

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Creating Methods from Interaction Diagrams

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Collection Classes in Code

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9.4 Test-Driven Development and Refactoring Test-Driven Development Refactoring

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Test-Driven Development An excellent practice promoted by the iterative and agile

XP method,and applicable to the UP, is test-driven development (TDD). It is also known as test-first development

In OO unit testing TDD-style, test code is written before the class to be tested, and the developer writes unit testing code for nearly all production

code. Unit testing framework

The most popular unit testing framework is the xUnit family (for many languages)

For Java, the popular version is JUnit. There's also an NUnit for .NET,

Example

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Refactoring Refactoring is a structured, disciplined method to

rewrite or restructure existing code without changing its external behavior, applying small transformation steps combined with re-

executing tests each step. Continuously refactoring code is another XP practice

and applicable to all iterative methods Code that's been well-refactored is short, tight, clear,

and without duplicationit looks like the work of a master programmer. Code that doesn't have these qualities smells bad or has

code smells.