1. Chapter 9 Design Engineering
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2. Analysis Model -> Design Model
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3. Design and Quality
the design must implement all of the explicit requirements contained in the analysis model, and it must accommodate all of the implicit requirements desired by the customer.
the design must be a readable, understandable guide for those who generate code and for those who test and subsequently support the software.
the design should provide a complete picture of the software, addressing the data, functional, and behavioral domains from an implementation perspective.
California State University, Los Angeles – cs337 – Part III

4. Quality Guidelines
A design should exhibit an architecture that (1) has been created using recognizable architectural styles or patterns, (2) is composed of components that exhibit good design characteristics and (3) can be implemented in an evolutionary fashion
For smaller systems, design can sometimes be developed linearly.
A design should be modular; that is, the software should be logically partitioned into elements or subsystems
A design should contain distinct representations of data, architecture, interfaces, and components.
A design should lead to data structures that are appropriate for the classes to be implemented and are drawn from recognizable data patterns.
A design should lead to components that exhibit independent functional characteristics.
A design should lead to interfaces that reduce the complexity of connections between components and with the external environment.
A design should be derived using a repeatable method that is driven by information obtained during software requirements analysis.
A design should be represented using a notation that effectively communicates its meaning.
California State University, Los Angeles – cs337 – Part III

5. Design Principles
The design process should not suffer from ‘tunnel vision.’
The design should be traceable to the analysis model.
The design should not reinvent the wheel.
The design should “minimize the intellectual distance” [DAV95] between the software and the problem as it exists in the real world.
The design should exhibit uniformity and integration.
The design should be structured to accommodate change.
The design should be structured to degrade gently, even when aberrant data, events, or operating conditions are encountered.
Design is not coding, coding is not design.
The design should be assessed for quality as it is being created, not after the fact.
The design should be reviewed to minimize conceptual (semantic) errors.
From Davis [DAV95]
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6. Fundamental Concepts abstraction—data, procedure, control
architecture—the overall structure of the software
patterns—”conveys the essence” of a proven design solution
modularity—compartmentalization of data and function
hiding—controlled interfaces
Functional independence—single-minded function and low coupling
refinement—elaboration of detail for all abstractions
Refactoring—a reorganization technique that simplifies the design
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7. Data Abstraction door manufacturer model number type swing direction
inserts
lights
type
number
weight
opening mechanism
implemented as a data structure
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8. Procedural Abstraction
open
details of enter
algorithm
implemented with a "knowledge" of the
object that is associated with enter
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9. Architecture
“The overall structure of the software and the ways in which that structure provides conceptual integrity for a system.” [SHA95a]
Structural properties. This aspect of the architectural design representation defines the components of a system (e.g., modules, objects, filters) and the manner in which those components are packaged and interact with one another. For example, objects are packaged to encapsulate both data and the processing that manipulates the data and interact via the invocation of methods
Extra-functional properties. The architectural design description should address how the design architecture achieves requirements for performance, capacity, reliability, security, adaptability, and other system characteristics.
Families of related systems. The architectural design should draw upon repeatable patterns that are commonly encountered in the design of families of similar systems. In essence, the design should have the ability to reuse architectural building blocks.
California State University, Los Angeles – cs337 – Part III

10. Patterns Design Pattern Template
Pattern name—describes the essence of the pattern in a short but expressive name
Intent—describes the pattern and what it does
Also-known-as—lists any synonyms for the pattern
Motivation—provides an example of the problem
Applicability—notes specific design situations in which the pattern is applicable
Structure—describes the classes that are required to implement the pattern
Participants—describes the responsibilities of the classes that are required to implement the pattern
Collaborations—describes how the participants collaborate to carry out their responsibilities
Consequences—describes the “design forces” that affect the pattern and the potential trade-offs that must be considered when the pattern is implemented
Related patterns—cross-references related design patterns
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11. Modular Design
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12. Modularity: Trade-offs
What is the "right" number of modules
for a specific software design?
module development cost
cost of
software
module
integration
cost
optimal number
number of modules
of modules
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13. Information Hiding module clients • algorithm controlled
interface
• data structure
• details of external interface
• resource allocation policy
clients
"secret"
a specific design decision
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14. Why Information Hiding?
reduces the likelihood of “side effects”
limits the global impact of local design decisions
emphasizes communication through controlled interfaces
discourages the use of global data
leads to encapsulation—an attribute of high quality design
results in higher quality software
California State University, Los Angeles – cs337 – Part III

15. Stepwise Refinement open walk to door; reach for knob; open door;
repeat until door opens
turn knob clockwise;
walk through;
if knob doesn't turn, then
close door.
take key out;
find correct key;
insert in lock;
endif
pull/push door
move out of way;
end repeat
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16. Functional Independence
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17. Sizing Modules: Two Views
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18. Refactoring
Fowler [FOW99] defines refactoring in the following manner:
"Refactoring is the process of changing a software system in such a way that it does not alter the external behavior of the code [design] yet improves its internal structure.”
When software is refactored, the existing design is examined for
redundancy
unused design elements
inefficient or unnecessary algorithms
poorly constructed or inappropriate data structures
or any other design failure that can be corrected to yield a better design.
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19. OO Design Concepts Design classes
Entity classes
Boundary classes
Controller classes
Inheritance—all responsibilities of a superclass is immediately inherited by all subclasses
Messages—stimulate some behavior to occur in the receiving object
Polymorphism—a characteristic that greatly reduces the effort required to extend the design
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20. Design Classes
Analysis classes are refined during design to become entity classes
Boundary classes are developed during design to create the interface (e.g., interactive screen or printed reports) that the user sees and interacts with as the software is used.
Boundary classes are designed with the responsibility of managing the way entity objects are represented to users.
Controller classes are designed to manage
the creation or update of entity objects;
the instantiation of boundary objects as they obtain information from entity objects;
complex communication between sets of objects;
validation of data communicated between objects or between the user and the application.
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21. Inheritance Design options:
The class can be designed and built from scratch. That is, inheritance is not used.
The class hierarchy can be searched to determine if a class higher in the hierarchy (a superclass)contains most of the required attributes and operations. The new class inherits from the superclass and additions may then be added, as required.
The class hierarchy can be restructured so that the required attributes and operations can be inherited by the new class.
Characteristics of an existing class can be overridden and different versions of attributes or operations are implemented for the new class.
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22. Messages
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23. Polymorphism Conventional approach …
case of graphtype:
if graphtype = linegraph then DrawLineGraph (data);
if graphtype = piechart then DrawPieChart (data);
if graphtype = histogram then DrawHisto (data);
if graphtype = kiviat then DrawKiviat (data);
end case;
All of the graphs become subclasses of a general class called graph. Using a concept called overloading [TAY90], each subclass defines an operation called draw. An object can send a draw message to any one of the objects instantiated from any one of the subclasses. The object receiving the message will invoke its own draw operation to create the appropriate graph.
graphtype draw
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24. The Design Model
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25. Design Model Elements Data elements Architectural elements
Data model --> data structures
Data model --> database architecture
Architectural elements
Application domain
Analysis classes, their relationships, collaborations and behaviors are transformed into design realizations
Patterns and “styles” (Chapter 10)
Interface elements
the user interface (UI)
external interfaces to other systems, devices, networks or other producers or consumers of information
internal interfaces between various design components.
Component elements
Deployment elements
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26. Interface Elements
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27. Component Elements
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28. Deployment Elements
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29. Design Patterns
The best designers in any field have an uncanny ability to see patterns that characterize a problem and corresponding patterns that can be combined to create a solution
A description of a design pattern may also consider a set of design forces.
Design forces describe non-functional requirements (e.g., ease of maintainability, portability) associated the software for which the pattern is to be applied.
The pattern characteristics (classes, responsibilities, and collaborations) indicate the attributes of the design that may be adjusted to enable the pattern to accommodate a variety of problems.
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30. Frameworks
A framework is not an architectural pattern, but rather a skeleton with a collection of “plug points” (also called hooks and slots) that enable it to be adapted to a specific problem domain.
Gamma et al note that:
Design patterns are more abstract than frameworks.
Design patterns are smaller architectural elements than frameworks
Design patterns are less specialized than frameworks
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31. Chapter 10 Architectural Design
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32. Why Architecture?
The architecture is not the operational software. Rather, it is a representation that enables a software engineer to:
(1) analyze the effectiveness of the design in meeting its stated requirements,
(2) consider architectural alternatives at a stage when making design changes is still relatively easy, and
(3) reduce the risks associated with the construction of the software.
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33. Why is Architecture Important?
Representations of software architecture are an enabler for communication between all parties (stakeholders) interested in the development of a computer-based system.
The architecture highlights early design decisions that will have a profound impact on all software engineering work that follows and, as important, on the ultimate success of the system as an operational entity.
Architecture “constitutes a relatively small, intellectually graspable model of how the system is structured and how its components work together” [BAS03].
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34. Data Design At the architectural level …
Design of one or more databases to support the application architecture
Design of methods for ‘mining’ the content of multiple databases
navigate through existing databases in an attempt to extract appropriate business-level information
Design of a data warehouse—a large, independent database that has access to the data that are stored in databases that serve the set of applications required by a business
database
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35. Data Design At the component level …
refine data objects and develop a set of data abstractions
implement data object attributes as one or more data structures
review data structures to ensure that appropriate relationships have been established
simplify data structures as required
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36. Data Design—Component Level
1. The systematic analysis principles applied to function and behavior should also be applied to data.
2. All data structures and the operations to be performed on each should be identified.
3. A data dictionary should be established and used to define both data and program design.
4. Low level data design decisions should be deferred until late in the design process.
5. The representation of data structure should be known only to those modules that must make direct use of the data contained within the structure.
6. A library of useful data structures and the operations that may be applied to them should be developed.
7. A software design and programming language should support the specification and realization of abstract data types.
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37. Architectural Styles Data-centered architectures
Each style describes a system category that encompasses: (1) a set of components (e.g., a database, computational modules) that perform a function required by a system, (2) a set of connectors that enable “communication, coordination and cooperation” among components, (3) constraints that define how components can be integrated to form the system, and (4) semantic models that enable a designer to understand the overall properties of a system by analyzing the known properties of its constituent parts.
Data-centered architectures
Data flow architectures
Call and return architectures
Object-oriented architectures
Layered architectures
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38. Data-Centered Architecture
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39. Data Flow Architecture
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40. Call and Return Architecture
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41. Layered Architecture
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42. Architectural Patterns
Concurrency—applications must handle multiple tasks in a manner that simulates parallelism
operating system process management pattern
task scheduler pattern
Persistence—Data persists if it survives past the execution of the process that created it. Two patterns are common:
a database management system pattern that applies the storage and retrieval capability of a DBMS to the application architecture
an application level persistence pattern that builds persistence features into the application architecture
Distribution— the manner in which systems or components within systems communicate with one another in a distributed environment
A broker acts as a ‘middle-man’ between the client component and a server component.
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43. Architectural Design The software must be placed into context
the design should define the external entities (other systems, devices, people) that the software interacts with and the nature of the interaction
A set of architectural archetypes should be identified
An archetype is an abstraction (similar to a class) that represents one element of system behavior
The designer specifies the structure of the system by defining and refining software components that implement each archetype
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44. Architectural Context
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45. Archetypes
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46. Component Structure
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47. Refined Component Structure
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48. Analyzing Architectural Design
1. Collect scenarios.
2. Elicit requirements, constraints, and environment description.
3. Describe the architectural styles/patterns that have been chosen to address the scenarios and requirements:
• module view
• process view
• data flow view
4. Evaluate quality attributes by considered each attribute in isolation.
5. Identify the sensitivity of quality attributes to various architectural attributes for a specific architectural style.
6. Critique candidate architectures (developed in step 3) using the sensitivity analysis conducted in step 5.
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49. An Architectural Design Method
customer requirements
"four bedrooms, three baths,
lots of glass ..."
architectural design
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50. Deriving Program Architecture
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51. Partitioning the Architecture
“horizontal” and “vertical” partitioning are required
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52. Horizontal Partitioning
define separate branches of the module hierarchy for each major function
use control modules to coordinate communication between functions
function 1
function 3
function 2
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53. Vertical Partitioning: Factoring
design so that decision making and work are stratified
decision making modules should reside at the top of the architecture
decision-makers
workers
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54. Why Partitioned Architecture?
results in software that is easier to test
leads to software that is easier to maintain
results in propagation of fewer side effects
results in software that is easier to extend
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55. Structured Design
objective: to derive a program architecture that is partitioned
approach:
the DFD is mapped into a program architecture
the PSPEC and STD are used to indicate the content of each module
notation: structure chart
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56. Flow Characteristics Transform flow Transaction flow
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57. General Mapping Approach
isolate incoming and outgoing flow
boundaries; for transaction flows, isolate
the transaction center
working from the boundary outward, map
DFD transforms into corresponding modules
add control modules as required
refine the resultant program structure
using effective modularity concepts
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58. Transform Mapping
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59. Factoring
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60. First Level Factoring main program controller output input processing
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61. Second Level Mapping
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62. Transaction Flow incoming flow action path T
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63. Transaction Example fixture fixture setting servos commands operator
process
report
operator
display
commands
screen
robot control
robot
control
software
assembly
record
in reality, other
commands
would also be shown
California State University, Los Angeles – cs337 – Part III

64. Refining the Analysis Model1.
write an English language processing narrative
for the level 01 flow model 2.
apply noun/verb parse to isolate processes, data
items, store and entities 3.
develop level 02 and 03 flow models 4.
create corresponding data dictionary entries 5.
refine flow models as appropriate
... now, we're ready to begin design!
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65. Deriving Level 1 Processing narrative for " process operator commands"
Process operator command software reads operator commands from
the cell operator. An error message is displayed for invalid commands.
The command type is determined for valid commands and appropriate
action is taken. When fixture commands are encountered, fixture
status is analyzed and a fixture setting is output to the fixture servos.
When a report is selected, the assembly record file is read and a
report is generated and displayed on the operator display screen.
noun-verb
When robot control switches are selected, control values are sent to
parse
the robot control system.
Process operator command software
reads
operator
commands
from
the cell
operator
. An
error message is
displayed
for
invalid commands .
The
command type is
determined
for
valid commands
and appropriate
action is
taken
. When
fixture commands
are
encountered ,
fixture
status is
analyzed
and a
fixture setting is
output
to the
fixture servos .
When a
report is
selected,
the
assembly record file is
read
and a
report is
generated
and
displayed
on the operator
display screen .
When
robot control switches
are
selected ,
control value
s are
sent to
the
robot control system.
California State University, Los Angeles – cs337 – Part III

66. Level 1 Data Flow Diagram
operator
Error msg
fixture
servos
commands
read
operator
commands
status
analyze
fixture
status
determine
command
type
Fixture setting
fixture
Valid
command
display
screen
select report
control robot
report
generate
send
control
value
assembly record
robot control
California State University, Los Angeles – cs337 – Part III

67. Level 2 Data Flow Diagram
error msg
command
produce
error msg
read
command
fixture setting
format
setting
status
determine
setting
validate
command
invalid command
read
fixture
status
command
raw setting
combined
status
determine
type
valid command
read
record
robot control
record
calculate
output
values
send
control
value
values
format
report
assembly
record
report
start/stop
California State University, Los Angeles – cs337 – Part III

68. Transaction Mapping Principles
isolate the incoming flow path
define each of the action paths by looking for
the "spokes of the wheel"
assess the flow on each action path
define the dispatch and control structure
map each action path flow individually
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69. Transaction Mapping Data flow model mapping program structure f a e bx1 g i
program structure l h k j b t m a x2 x3 x4 n d e f g h
x3.1 l m n i j k
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70. Isolate Flow Paths error msg command produce error msg read command
fixture setting
format
setting
status
determine
setting
validate
command
invalid command
read
fixture
status
command
raw setting
combined
status
determine
type
valid command
read
record
robot control
record
calculate
output
values
send
control
value
values
format
report
assembly
record
report
start/stop
California State University, Los Angeles – cs337 – Part III

71. Map the Flow Model
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72. Refining the Structure Chart
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73. Chapter 11 Component-Level Design
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74. What is a Component?
OMG Unified Modeling Language Specification [OMG01] defines a component as
“… a modular, deployable, and replaceable part of a system that encapsulates implementation and exposes a set of interfaces.”
OO view: a component contains a set of collaborating classes
Conventional view: logic, the internal data structures that are required to implement the processing logic, and an interface that enables the component to be invoked and data to be passed to it.
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75. OO Component
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76. Conventional Component
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77. Basic Design Principles
The Open-Closed Principle (OCP). “A module [component] should be open for extension but closed for modification.
The Liskov Substitution Principle (LSP). “Subclasses should be substitutable for their base classes.
Dependency Inversion Principle (DIP). “Depend on abstractions. Do not depend on concretions.”
The Interface Segregation Principle (ISP). “Many client-specific interfaces are better than one general purpose interface.
The Release Reuse Equivalency Principle (REP). “The granule of reuse is the granule of release.”
The Common Closure Principle (CCP). “Classes that change together belong together.”
The Common Reuse Principle (CRP). “Classes that aren’t reused together should not be grouped together.”
Source: Martin, R., “Design Principles and Design Patterns,” downloaded from
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78. Design Guidelines Components Interfaces Dependencies and Inheritance
Naming conventions should be established for components that are specified as part of the architectural model and then refined and elaborated as part of the component-level model
Interfaces
Interfaces provide important information about communication and collaboration (as well as helping us to achieve the OPC)
Dependencies and Inheritance
it is a good idea to model dependencies from left to right and inheritance from bottom (derived classes) to top (base classes).
California State University, Los Angeles – cs337 – Part III

79. Cohesion Conventional view: OO view: Levels of cohesion
the “single-mindedness” of a module
OO view:
cohesion implies that a component or class encapsulates only attributes and operations that are closely related to one another and to the class or component itself
Levels of cohesion
Functional
Layer
Communicational
Sequential
Procedural
Temporal
utility
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80. Coupling Conventional view: OO view: Level of coupling
The degree to which a component is connected to other components and to the external world
OO view:
a qualitative measure of the degree to which classes are connected to one another
Level of coupling
Content
Common
Control
Stamp
Data
Routine call
Type use
Inclusion or import
External
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81. Component Level Design-I
Step 1. Identify all design classes that correspond to the problem domain.
Step 2. Identify all design classes that correspond to the infrastructure domain.
Step 3. Elaborate all design classes that are not acquired as reusable components.
Step 3a. Specify message details when classes or component collaborate.
Step 3b. Identify appropriate interfaces for each component.
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82. Component-Level Design-II
Step 3c. Elaborate attributes and define data types and data structures required to implement them.
Step 3d. Describe processing flow within each operation in detail.
Step 4. Describe persistent data sources (databases and files) and identify the classes required to manage them.
Step 5. Develop and elaborate behavioral representations for a class or component.
Step 6. Elaborate deployment diagrams to provide additional implementation detail.
Step 7. Factor every component-level design representation and always consider alternatives.
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83. Collaboration Diagram
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84. Refactoring
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85. Activity Diagram
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86. Statechart
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87. Object Constraint Language (OCL)
complements UML by allowing a software engineer to use a formal grammar and syntax to construct unambiguous statements about various design model elements
simplest OCL language statements are constructed in four parts:
(1) a context that defines the limited situation in which the statement is valid;
(2) a property that represents some characteristics of the context (e.g., if the context is a class, a property might be an attribute)
(3) an operation (e.g., arithmetic, set-oriented) that manipulates or qualifies a property, and
(4) keywords (e.g., if, then, else, and, or, not, implies) that are used to specify conditional expressions.
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88. OCL Example
context PrintJob::validate(upperCostBound : Integer, custDeliveryReq :
Integer)
pre: upperCostBound > 0
and custDeliveryReq > 0
and self.jobAuthorization = 'no'
post: if self.totalJobCost <= upperCostBound
and self.deliveryDate <= custDeliveryReq
then
self.jobAuthorization = 'yes'
endif
California State University, Los Angeles – cs337 – Part III

89. Algorithm Design the closest design activity to coding the approach:
review the design description for the component
use stepwise refinement to develop algorithm
use structured programming to implement procedural logic
use ‘formal methods’ to prove logic
California State University, Los Angeles – cs337 – Part III

90. Stepwise Refinement open walk to door; reach for knob; open door;
repeat until door opens
turn knob clockwise;
walk through;
if knob doesn't turn, then
close door.
take key out;
find correct key;
insert in lock;
endif
pull/push door
move out of way;
end repeat
California State University, Los Angeles – cs337 – Part III

91. Algorithm Design Model
represents the algorithm at a level of detail that can be reviewed for quality
options:
graphical (e.g. flowchart, box diagram)
pseudocode (e.g., PDL) choice of many
programming language
decision table
conduct walkthrough to assess quality
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92. Structured Programming for Procedural Design
uses a limited set of logical constructs:
sequence
conditional
— if-then-else, select-case
loops
— do-while, repeat until
leads to more readable, testable code
can be used in conjunction with ‘proof of correctness’
important for achieving high quality,
but not enough
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93. A Structured Procedural Design
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94. Decision Table
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95. Program Design Language (PDL)
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96. Why Design Language?
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97. Chapter 12 User Interface Design
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98. Interface Design Easy to learn? Easy to use? Easy to understand?
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99. Interface Design Typical Design Errors lack of consistency
too much memorization
no guidance / help
no context sensitivity
poor response
Arcane/unfriendly
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100. Golden Rules Place the user in control Reduce the user’s memory load
Make the interface consistent
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101. Place the User in Control
Define interaction modes in a way that does not force a user into unnecessary or undesired actions.
Provide for flexible interaction.
Allow user interaction to be interruptible and undoable.
Streamline interaction as skill levels advance and allow the interaction to be customized.
Hide technical internals from the casual user.
Design for direct interaction with objects that appear on the screen.
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102. Reduce the User’s Memory Load
Reduce demand on short-term memory.
Establish meaningful defaults.
Define shortcuts that are intuitive.
The visual layout of the interface should be based on a real world metaphor.
Disclose information in a progressive fashion.
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103. Make the Interface Consistent
Allow the user to put the current task into a meaningful context.
Maintain consistency across a family of applications.
If past interactive models have created user expectations, do not make changes unless there is a compelling reason to do so.
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104. User Interface Design Models
User model — a profile of all end users of the system
Design model — a design realization of the user model
Mental model (system perception) — the user’s mental image of what the interface is
Implementation model — the interface “look and feel” coupled with supporting information that describe interface syntax and semantics
California State University, Los Angeles – cs337 – Part III

105. User Interface Design Process
California State University, Los Angeles – cs337 – Part III

106. Interface Analysis Interface analysis means understanding
(1) the people (end-users) who will interact with the system through the interface;
(2) the tasks that end-users must perform to do their work,
(3) the content that is presented as part of the interface
(4) the environment in which these tasks will be conducted.
California State University, Los Angeles – cs337 – Part III

107. User Analysis
Are users trained professionals, technician, clerical, or manufacturing workers?
What level of formal education does the average user have?
Are the users capable of learning from written materials or have they expressed a desire for classroom training?
Are users expert typists or keyboard phobic?
What is the age range of the user community?
Will the users be represented predominately by one gender?
How are users compensated for the work they perform?
Do users work normal office hours or do they work until the job is done?
Is the software to be an integral part of the work users do or will it be used only occasionally?
What is the primary spoken language among users?
What are the consequences if a user makes a mistake using the system?
Are users experts in the subject matter that is addressed by the system?
Do users want to know about the technology the sits behind the interface?
California State University, Los Angeles – cs337 – Part III

108. Task Analysis and Modeling
Answers the following questions …
What work will the user perform in specific circumstances?
What tasks and subtasks will be performed as the user does the work?
What specific problem domain objects will the user manipulate as work is performed?
What is the sequence of work tasks—the workflow?
What is the hierarchy of tasks?
Use-cases define basic interaction
Task elaboration refines interactive tasks
Object elaboration identifies interface objects (classes)
Workflow analysis defines how a work process is completed when several people (and roles) are involved
California State University, Los Angeles – cs337 – Part III

109. Swimlane Diagram
California State University, Los Angeles – cs337 – Part III

110. Analysis of Display Content
Are different types of data assigned to consistent geographic locations on the screen (e.g., photos always appear in the upper right hand corner)?
Can the user customize the screen location for content?
Is proper on-screen identification assigned to all content?
If a large report is to be presented, how should it be partitioned for ease of understanding?
Will mechanisms be available for moving directly to summary information for large collections of data.
Will graphical output be scaled to fit within the bounds of the display device that is used?
How will color to be used to enhance understanding?
How will error messages and warning be presented to the user?
California State University, Los Angeles – cs337 – Part III

111. Interface Design Steps
Using information developed during interface analysis (SEPA, Section 12.3), define interface objects and actions (operations).
Define events (user actions) that will cause the state of the user interface to change. Model this behavior.
Depict each interface state as it will actually look to the end-user.
Indicate how the user interprets the state of the system from information provided through the interface.
California State University, Los Angeles – cs337 – Part III

112. Interface Design Patterns
Patterns are available for
The complete UI
Page layout
Forms and input
Tables
Direct data manipulation
Navigation
Searching
Page elements
e-Commerce
California State University, Los Angeles – cs337 – Part III

113. Design Issues Response time Help facilities Error handling
Menu and command labeling
Application accessibility
Internationalization
California State University, Los Angeles – cs337 – Part III

114. Design Evaluation Cycle
California State University, Los Angeles – cs337 – Part III