Elaboration 1

8/3/2019 Elaboration 1

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OBJECT ORIENTED ANALYSISAND DESIGN-UNIT II

P. Vinitha


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Objectives

Elaboration

Domain Models

Finding conceptual classes and description classes Associations

Attributes


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UP Phases a recap

Phases describe the functional implementation of

the project. There are several iterations in each

phase. Project phases and general percent of the

project are:

Inception - 5%

Elaboration - 20%

Construction - 65% Transition - 10%


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Inception Phase

At the end of the inception phase is the first major

project milestone:

Stakeholder concurrence on scope definition and

cost/schedule estimates.

Depth and breadth of any architectural prototype that

was developed.

Actual expenditures versus planned expenditures.


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Elaboration Phase

The purpose of the elaboration phase is to analyze the

problem domain, establish a sound architectural

foundation, develop the project plan, and eliminate

the highest risk elements of the project. Elaboration is the initial series of iterations during

which, on a normal project:

The core, risky software architecture is programmed and

tested

The majority of requirements are discovered and stabilized

The major risks are mitigated or retired


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Iteration

The word "iterative" means that it involvesrepetition.

The UML process allows for designs to have

iterative processes. each iteration add some function (based on a use

case) to the system.

Additional features or functions are added in

succeeding iterations.

Each iteration will have a time limit and will havespecific goals. This is called "time boxing".


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Iteration


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Elaboration Phase (Example)

The requirements for the first iteration of the NextGenPOS application follow: Implement a basic, key scenario of the Process Sale use

case: entering items and receiving a cash payment.

Implement a Start Up use case as necessary to support theinitialization needs of the iteration.

Nothing fancy or complex is handled, just a simple happypath scenario, and the design and implementation tosupport it.

There is no collaboration with external services, such as atax calculator or product database.

No complex pricing rules are applied


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Sample Elaboration Artifacts

Artifact Comment

Domain Model This is a visualization of the domain concepts; it is similar to a static

information model of the domain entities.

Design Model This is the set of diagrams that describes the logical design. This

includes software class diagrams, object interaction diagrams,package diagrams, and so forth.

Software

Architecture

Document

A learning aid that summarizes the key architectural issues and their

resolution in the design. It is a summary of the outstanding design

ideas and their motivation in the system.

Data Model This includes the database schemas, and the mapping strategies

between object and non-object representations.

Use-Case

Storyboards, UI

Prototypes

A description of the user interface, paths of navigation, usability

models, and so forth.


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Elaboration Phase

Planning the Next Iteration

Organize requirements and iterations by risk,coverage, and criticality.

Risk includes both technical complexity and otherfactors, such as uncertainty of effort or usability.

Coverage implies that all major parts of the system areat least touched on in early iterations perhaps a "wideand shallow" implementation across manycomponents.

Criticality refers to functions the client considers ofhigh business value


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Elaboration Phase

Ranking the criteria

Use cases or use case scenarios are ranked for

implementation

The ranking is done before iteration-1, but then againbefore iteration-2, and so forth, as new requirements and

new insights influence the order.

Rank Requirement (Use Case or Feature) Comment

High Process Sale

Logging

Scores high on all rankings.

Pervasive. Hard to add late.

Medium Maintain Users

Affects security subdomain.

Low


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Elaboration Phase

The outcome of the elaboration phase is: A use-case model (at least 80% complete) all use cases and

actors have been identified, and most usecase descriptionshave been developed.

Supplementary requirements capturing the non functionalrequirements and any requirements that are not associated

with a specific use case.

A Software Architecture Description.

An executable architectural prototype.

A revised risk list and a revised business case.

A development plan for the overall project.

An updated development case specifying the process to beused.

A preliminary user manual (optional).


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Domain Model


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Domain Model

A domain model is a visual representation ofconceptual classes or real-situation objects in adomain.

Domain models have also been called conceptual

models A UML domain model will relate objects in the system

domain to each other.

It will define concepts and terms.

Objects in the domain model can be:Physical objects

Abstract concepts


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Domain Model (Example)

It illustrates that the conceptual classes of

Payment and Sale are significant in this domain


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Domain Model

Syntax


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Domain Model

There can be multiple relationships between objects inthe domain model.

In the domain model the following are shown:

Concepts (Objects) Attributes of Objects - Attributes must be simple attributes

such as numbers. They cannot be objects, dimensionednumbers, or keys to part of a database.

Association between objects

Multiplicity

Optional direction of relationship arrow

Optional role of object


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Domain Model a "Visual Dictionary

It shows an visual abstraction of the conceptualclasses, because there are many other things onecould communicate about registers, sales, and soforth.

It's easy to understand the terms and especially theirrelationships in a visual language, since our brains aregood at understanding visual elements and lineconnections.

Therefore, the domain model is a visual dictionary ofthe notable abstractions, domain vocabulary, andinformation content of the domain.


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Domain Model a Picture ofSoftware

Business Objects

A UP Domain Model is a visualization of things in areal-situation domain of interest, not of softwareobjects such as Java or C# classes, or software

objects with responsibilities . The following elements are not suitable in a

domain model:

Software artifacts, such as a window or a database,

unless the domain being modeled is of softwareconcepts, such as a model of graphical user interfaces.

Responsibilities or methods.[


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Domain Model a Picture ofSoftware

Business Objects


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Steps to Create a Domain Model

Identify Candidate Conceptual classes

Draw them in a Domain Model, the vocabulary of

the domain

Add associations necessary to record the

relationships that must be retained

Add attributes necessary for information to be

preserved Apply existing Analysis Patterns


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Domain Model

What are Conceptual Classes?

A conceptual class is an idea, thing, or object.

More formally, a conceptual class may be

considered in terms of its symbol, intension, and

extension .

Symbol words or images representing a conceptual class.

Intension the definition of a conceptual class.

Extension the set of examples to which the conceptual

class applies.


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Domain Model

Conceptual class example for the event of a purchase transaction.

Symbol - Sale.

he intension of a Sale - Represents the event of a purchase transaction, and has a date and

time.

he extension ofSale - The set of all sale instances in the universe.


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Domain Models

Three Strategies to Find Conceptual Classes

Reuse or modify existing models.

Use a category list.

Identify noun phrases.


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Domain Models

Method 2: Use a Category List

We can kick-start the creation of a domain model by

making a list of candidate conceptual classes


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Domain Models - Find Conceptual Class

Conceptual Class Category Examples

business transactions

Guideline: These are critical (they involve money), so start with

transactions.

Sale, Payment

Transaction line items

Guideline: Transactions often come with related line items, soconsider these next.

SalesLineItem

Product or service related to a transaction or transaction line item

Guideline: Transactions are for something (a product or service).

Consider these next.

Item

where is the transaction recorded?

Guideline: Important.

Register, Ledger

Roles of people or organizations related to the transaction; actors

in the use case

Guideline:We usually need to know about the parties involved in a

transaction.

Cashier, Customer,

Place of transaction; place of service Store

Conceptual Class Category List.


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Domain Models - Find Conceptual Class

Method 3: Finding Conceptual Classes with Noun PhraseIdentification

Another useful technique is linguistic analysis: Identify the nounsand noun phrases in textual descriptions of a domain, and considerthem as candidate conceptual classes or attributes

Main Success Scenario (or Basic Flow):

Customer arrives at a POS checkout with goods and/or services topurchase.

Cashier starts a new sale.

Cashier enters item identifier.

System records sale line item and presents item description, price, andrunning total. Price calculated from a set of price rules.

Cashier repeats steps 2-3 until indicates done

Elaboration 1

Documents