Software Architecture EvaluationHafiz Hasanov

Horst Lichter, Software Construction, RWTH Aachen Universityhorst.lichter@swc.rwth-aachen.de

Introduction

Benefits vs. Costs

Challenges

Quality of SA

Classification

Some methods introduced

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Software Architecture(SA) evaluation is a means to achieve SA quality.

Verify quality attributes Identify risks Choose between alternative SA-s Product line potential

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SA evaluation

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Benefits Helps to detect poor design decisions early Positively affects the communication between stakeholders Filters out some possible defects and/or unclear specifications from SA

documentation

Costs Additional effort and recourses Expert evaluation team members

Benefits vs Costs

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Stakeholders‘ involvement

Challenges

Expert team members

5

Quality of SA

The quality of a SA is measured by its relevance to project non-functional requirements.

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Performance Usability Reliability Security Modifiability Sustainability Adaptability

Example quality attributes

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Early evaluation methods Scenario-based Mathematical model-based Simulation-based Experience-based

Late evaluation methods Metrics-based Tool-based

Early vs. Late

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Questioning(Qualitative) Scenarios Questionnaires Checklists

Measuring(Quantitative) Metrics Prototypes, simulations, experiments

Questioning vs. Measuring

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Aims to verify the SA against architectural approaches like design principles and architectural styles.

Early evaluation

Scenario-based method

Questioning method

SAAMSoftware Architecture Analysis Method

Investigation &Analysis

1. Present the ATAM

2. Present business drivers.

Present architecture.

Identify architectural approaches.

Generate quality attribute utility tree

Analyze architectural approaches

Brainstorm & prioritize

Analyze architectural approaches

Present results

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Reveals the sensitivity points, trade-off points and potential risks.

Early evaluation

Scenario-based

Questioning technique

ATAMArchitecture Trade-off Analysis Method

Presentation

Testing

Results

SBAR aims to iteratively reengineer the SA which best suits the quality requirements.

Early evaluation

Questioning or

Measuring technique.

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SBARScenario Based Architecture Reengineering

SBAR aims to iteratively reengineer the SA which best suits the quality requirements.

Early evaluation

Questioning or

Measuring technique. Scenario-based Mathematical model-based Simulation-based Experience-based

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SBARScenario Based Architecture Reengineering

SBAR aims to iteratively reengineer the SA which best suits the quality requirements.

Early evaluation

Questioning or

Measuring technique.

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SBARScenario Based Architecture Reengineering

Impose architectural style Impose architectural pattern Apply design pattern Convert non-functional

requirements to functionality Distribute requirements

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Aims at assessing the modifiability of an SA. ALMA needs to be complemented with other methods for complete evaluation of the SA.

Early evaluation.

Scenario-based method.

Questioning technique might also include measuring activities.

ALMAArchitecture-Level Modifiability Analysis

• Maintenance cost prediction

• Risk assessment• Alternative SA-s

Goal setting

• Modifiability related view

SA respresentation

• Dependent on goal of evaluation

Change scenarios elicitation

• Direct components• Nature of effects• Ripple effects

Change scenarios evaluation

• Analysis• Visualization

Interpreting results

Set of quality attributes are

chosen

Guidelines and respective metrics

Planned SA Actual SA

Deviations

Recommendations to recover

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Late evaluation method, which aims to prevent the SA from deviation during implementation.

Late evaluation.

Measuring technique.

Tvedt et al’s method

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Questions?

Thank you!