Chapter 10 Architectural Design - ocw.usu.ac.idocw.usu.ac.id/course/download/419-REKAYASA...Chapter 10 Architectural Design These courseware materials are to be used in conjunction
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Software Engineering: A Practitioner’s Approach, 6/eSoftware Engineering: A Practitioner’s Approach, 6/e
For University Use OnlyMay be reproduced ONLY for student use at the university level
when used in conjunction with Software Engineering: A Practitioner's Approach.Any other reproduction or use is expressly prohibited.
Why Architecture?Why Architecture?
The architecture is not the operational software. The architecture is not the operational software. Rather, it is a representation that enables a Rather, it is a representation that enables a software engineer to: software engineer to:
(1) analyze the effectiveness of the design in (1) analyze the effectiveness of the design in meeting its stated requirements, meeting its stated requirements,
meeting its stated requirements, meeting its stated requirements,
(2) consider architectural alternatives at a stage (2) consider architectural alternatives at a stage when making design changes is still relatively when making design changes is still relatively easy, and easy, and
(3) reduce the risks associated with the (3) reduce the risks associated with the construction of the software.construction of the software.
Why is Architecture Why is Architecture Important?Important?
�� Representations of software architecture are an enablerRepresentations of software architecture are an enabler for for communication between all parties (stakeholders) interested in the communication between all parties (stakeholders) interested in the development of a computerdevelopment of a computer--based system.based system.
�� The architecture highlights early design decisionsThe architecture highlights early design decisions that will have a that will have a
The architecture highlights early design decisionsThe architecture highlights early design decisions that will have a that will have a profound impact on all software engineering work that follows and, profound impact on all software engineering work that follows and, as important, on the ultimate success of the system as an as important, on the ultimate success of the system as an operational entity.operational entity.
�� Architecture “constitutes a relatively small, intellectually graspable Architecture “constitutes a relatively small, intellectually graspable modelmodel of how the system is structured and how its components work of how the system is structured and how its components work together” [BAS03].together” [BAS03].
Data DesignData Design
�� At the architectural level …At the architectural level …
�� Design of one or more databases to support the Design of one or more databases to support the application architectureapplication architecture
�� Design of methods for ‘Design of methods for ‘miningmining’ the content of multiple ’ the content of multiple
�� review data structures to ensure that appropriate review data structures to ensure that appropriate relationships have been establishedrelationships have been established
�� simplify data structures as requiredsimplify data structures as required
Data DesignData Design——Component LevelComponent Level1. The systematic analysis principles applied to function and 1. The systematic analysis principles applied to function and
behavior should also be applied to data. behavior should also be applied to data. 2. All data structures and the operations to be performed on each 2. All data structures and the operations to be performed on each
should be identified. should be identified.
3. A data dictionary should be established and used to define both 3. A data dictionary should be established and used to define both data and program design. data and program design.
4. Low level data design decisions should be deferred until late in 4. Low level data design decisions should be deferred until late in the design process. the design process.
the design process. the design process. 5. The representation of data structure should be known only to 5. The representation of data structure should be known only to
those modules that must make direct use of the data contained those modules that must make direct use of the data contained
within the structure. within the structure. 6. A library of useful data structures and the operations that may be 6. A library of useful data structures and the operations that may be
applied to them should be developed. applied to them should be developed.
7. A software design and programming language should support 7. A software design and programming language should support
the specification and realization of abstract data types.the specification and realization of abstract data types.
Architectural StylesArchitectural Styles
Each style describes a system category that encompasses: (1) a Each style describes a system category that encompasses: (1) a set of set of componentscomponents (e.g., a database, computational modules) that perform a (e.g., a database, computational modules) that perform a function required by a system, (2) a function required by a system, (2) a set of connectorsset of connectors that enable that enable “communication, coordination and cooperation” among components, “communication, coordination and cooperation” among components, (3) (3) constraintsconstraints that define how components can be integrated to form that define how components can be integrated to form the system, and (4) the system, and (4) semantic modelssemantic models that enable a designer to that enable a designer to understand the overall properties of a system by analyzing the known understand the overall properties of a system by analyzing the known properties of its constituent parts. properties of its constituent parts.
�� Concurrency Concurrency —— applications must handle multiple tasks in a applications must handle multiple tasks in a manner that enables parallelism manner that enables parallelism �� operating system process managementoperating system process management patternpattern
�� task schedulertask scheduler patternpattern
�� Persistence Persistence —— Data persists if it survives past the execution of Data persists if it survives past the execution of the process that created it. Two patterns are common: the process that created it. Two patterns are common:
�� a a database management systemdatabase management system pattern that applies the storage and pattern that applies the storage and
�� a a database management systemdatabase management system pattern that applies the storage and pattern that applies the storage and retrieval capability of a DBMS to the application architectureretrieval capability of a DBMS to the application architecture
�� an an application levelapplication level persistencepersistence pattern that builds persistence pattern that builds persistence features into the application architecturefeatures into the application architecture
�� Distribution Distribution —— the manner in which systems or components the manner in which systems or components within systems communicate with one another in a distributed within systems communicate with one another in a distributed environmentenvironment
�� AA brokerbroker acts as a ‘middleacts as a ‘middle--man’ between the client component and a man’ between the client component and a server component.server component.
Architectural DesignArchitectural Design
�� The software must be placed into contextThe software must be placed into context
�� the design should define the external entities (other systems, the design should define the external entities (other systems, devices, people) that the software interacts with and the nature devices, people) that the software interacts with and the nature of the interactionof the interaction
�� A set of architectural archetypes should be identifiedA set of architectural archetypes should be identified
�� A set of architectural archetypes should be identifiedA set of architectural archetypes should be identified
�� AnAn archetypearchetype is an abstraction (similar to a class) that is an abstraction (similar to a class) that represents one element of system behaviorrepresents one element of system behavior
�� The designer specifies the structure of the system by The designer specifies the structure of the system by defining and refining software components that defining and refining software components that implement each archetypeimplement each archetype
1. Collect scenarios. 1. Collect scenarios. 2. Elicit requirements, constraints, and environment 2. Elicit requirements, constraints, and environment description. description. 3. Describe the architectural styles/patterns that have been 3. Describe the architectural styles/patterns that have been chosen to address the scenarios and requirements:chosen to address the scenarios and requirements:
• module view• module view• process view• process view
• process view• process view• data flow view• data flow view
4. Evaluate quality attributes by considered each attribute 4. Evaluate quality attributes by considered each attribute in isolation. in isolation. 5. Identify the sensitivity of quality attributes to various 5. Identify the sensitivity of quality attributes to various architectural attributes for a specific architectural style. architectural attributes for a specific architectural style. 6. Critique candidate architectures (developed in step 3) 6. Critique candidate architectures (developed in step 3) using the sensitivity analysis conducted in step 5.using the sensitivity analysis conducted in step 5.
An Architectural Design MethodAn Architectural Design Method
Develop level 02 and 03 flow modelsDevelop level 02 and 03 flow models
Create corresponding data dictionary entriesCreate corresponding data dictionary entries
Refine flow models as appropriateRefine flow models as appropriate
... now, we're ready to begin design!... now, we're ready to begin design!
3.3.
4.4.
5.5.
Deriving Level 1Deriving Level 1Processing narrative for " process operator commands"Processing narrative for " process operator commands"
Process operator command software reads operator commands from Process operator command software reads operator commands from the cell operator. An error message is displayed for invalid commands. the cell operator. An error message is displayed for invalid commands. The command type is determined for valid commands and appropriate The command type is determined for valid commands and appropriate action is taken. When fixture commands are encountered, fixture action is taken. When fixture commands are encountered, fixture status is analyzed and a fixture setting is output to the fixture servos. 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 When a report is selected, the assembly record file is read and a report is generated and displayed on the operator display screen. report is generated and displayed on the operator display screen. When robot control switches are selected, control values are sent to When robot control switches are selected, control values are sent to the robot control system. the robot control system.
Processing narrative for " process operator commands"Processing narrative for " process operator commands"
the robot control system. the robot control system.
Process operator command software Process operator command software readsreads operator operator commandscommands from from the cell the cell operatoroperator. An . An error messageerror message is is displayeddisplayed for for invalid commandsinvalid commands. . The The command typecommand type is is determineddetermined for for valid commandsvalid commands and appropriate and appropriate action is action is takentaken. When . When fixture commandsfixture commands are are encounteredencountered, , fixture fixture statusstatus is is analyzedanalyzed and a and a fixture settingfixture setting is is outputoutput to the to the fixture servosfixture servos. . When a When a reportreport is is selectedselected,, the the assembly record fileassembly record file is is readread and a and a report is report is generatedgenerated and and displayeddisplayed on the operator on the operator display screendisplay screen. . When When robot control switchesrobot control switches are are selectedselected, , control valuecontrol values s are are sentsent to to the the robot control system. robot control system.