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Advanced Software EngineeringURL: http://lore.com/Advanced-Software-Engineering-Univaq/

DISIMDep.nt of Information Engineering, Computer Science and MathematicsUniversity of L’Aquila, Italy

LAB on Software Architecture

Vittorio Cortellessa and Henry Muccini vittorio.cortellessa@univaq.it;henry.muccini@univaq.it

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Copyright Notice

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Non Functional S.E.Performance modelingPerformance analysis

UML UML ProfilingLab

Intro to SASA Case study SA styleADLs Design Decisions Views/Viewpoints

Software Architecture

UML Extra Functional

Lectures

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Problem to be solved

I need a system that: Can detect and predict fire in a building Can communicate to the fire fighters Can communicate to the fire trucks Can route fire trucks towards different fires Can monitor the state of a fire

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System usage scenario There is some smoke on the first apartment in the 4th floor, on Avenue de Fortune 26. A smoke sensor detects the smoke, potential source of a fire, and informs a local server. The local server posts the information on-line, and this information is accessible from the fire station. The fire station has a view on all the alarms and warnings happening at the all time. The system monitors the status of alarms and informs the fire fighters about the entity of the fire, the time it started, the area covered by it, and other sensitive information. Based on such information, the system decides where to send the fire trucks (in case only a limited set of fires can be managed in parallel). The fire fighters jump into the fire truck, turn in their onboard computing system, and get information about the fastest way to get to destination. During the trip, they get all possible updates about the state of the fire. Based on this information, they may decide that a second truck is needed, or one is closer to Avenue de Fortune, or that their service is not needed anymore. When the fire fighters arrive to Avenue de Fortune 26, the entire 4th floor is on fire. By using other sensors, they may know how many people is trapped inside the building: this information is displayed on their devices. Fortunately, nobody is inside the building at this time. Before starting extinguishing the fire, the system discovers that there are some gas cylinders on the 6th floor. They first start securing those devices, and in parallel extinguishing the fire on the 4th floor.

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Overall Architecting Process

Architectural constraints and requirements

Ideas

Constraints

Req1:..Req2:..Req3:..………

Architectural requirements

C2

C3C1

C4

Software Architecture

Software Architecture

synthesis

C2

C3C1

C4Software Architecture

prototypeEvaluation and Decisions making

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Fire Rescue WSN Architecture

Features:• The system has to monitor buildings for humidity, voltage, pressure and

temperature, through WS nodes • Those are related factors to be used to prevent a fire

• Monitored data has to be stored• Statistical information has to be computed• Fire alarms need to be dispatched• Collected data and reports can be accessed via a Web Interface• A management unit receives alarms and warnings, and information to

locate the fire

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Fire Rescue WSN Architecture

- The system has to enable quick but effective decisions on how to fight the fire (in order to plan an Intelligent scheduling and resource allocation)

Non Functional Requirements:• All the alarms sent must be received• In the worst case scenario, alarms sent has to be received within 1

second • The Web application and the data must be secure and private• False alarms must be avoided

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Class Work

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By Next Lecture: readDraw your

architecture

Chapter 1

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Main Concerns

Main Design Decisions to be takenWhat to Model?How to Model?Multiple Views Is the produced one a Good architecture?How to use such an architecture?

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What to model? (1)

HW/SW/DeploymentComponent Types and InstancesStructural and behavioralComponents’ Nesting and sub-systemsWhat can I model, what I cannot ?Requirements and qualitiesStyles

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What to model? (2)

What to model?Which are the high-level components (high level)?Which are the possible configurations (home voting, cabin

voting, …)Components refinementInformation storing and distributionQoS, depending on the configuration (later on)Conflicts among choices (quality conflicts) (later on)What are the architectural-specific decisions?How do they affect the architecture? How the final

product?

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Multiple Views

Define an architecture from different viewpoints:Software ConfigurationHardware Configuration Deployment Configuration

Structural Behavioral

Architectural Styles

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How to model? (1)

There are three different options:Informal box-and-line notationsFormal Architecture Description LanguageUML

component ElevatorPanel is { state { vport : ViewportType; sub_vports : \set ViewportIDType; } invariant { #sub_vports \eqgreater 0; } interface { prov ip_newvpt: createViewport() : ViewportType;

... req ir_selshp: selectShipment(port : PortID; shp : ShipmentID); } operations { prov op_subvpt: { let vpt : ViewportIDType; pre vpt \not_in sub_vports; post (#~sub_vports = #sub_vports + 1) \and (vpt \in sub_vports); }

...

User1

Router Server

Timer

AlarmUR AlarmRS (c)Check1

Nofunc

Clock

AckSR (c)

AckRU1

User2

AlarmUR1

AlarmUR2

Check2

Check

AckRU2

C1

C3

C4

C2

C5

C4'

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How to model? (2)

DrawingPros, cons

Formal languagesPros, cons

Model-based NotationPros, cons

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Quality SA

The quality of a SA depends on how well it satisfies functional and non functional

requirements

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SA-based Analysis

Assessment:A Software Architecture should be realized in order to comply to requirements

Is my architecture really compliant to certain given requirements?

Conformance:An implementation should conform to the Architectural specification

Is my implementation really compliant to my architectural specification?The SA specification, when assessed, acts as an oracle, describing what expectedAnalysis can start even before the code is available

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Software Architecture-level Analysis

Much has been done for SA-level Analysis:Model and Consistency Checking SimulationTesting MonitoringDependence AnalysisPerformance and Reliability AnalysisTradeoff AnalysisComponents CompositionSecurity…

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Code Generation from SA specifications

The goal is to generate a skeleton code, reflecting architectural elements and decisionsThe main approaches so far:

AADLAda, C, Java

FujabaMDA approaches and model transformation

JavaAExtension to Java

ArchJavaThe ACME ADL concepts are automatically mapped into ArchJava concepts