© 2007 Pearson Education, Inc. Publishing as Pearson Addison-Wesley 1 Finalizing Software Architectures

© 2007 Pearson Education, Inc. Publishing as Pearson Addison-Wesley 2 Objectives  To present SAD quality characteristics  To survey different kinds of reviews  To present an example of an architecture inspection checklist  To present active design reviews in detail  To advocate continuous review during the design process

© 2007 Pearson Education, Inc. Publishing as Pearson Addison-Wesley 3 Topics  SAD quality characteristics  Reviews  Types of reviews  An architecture inspection checklist  Active design reviews  Continuous review

© 2007 Pearson Education, Inc. Publishing as Pearson Addison-Wesley 4 SAD Quality Characteristics 1  Feasibility—The SAD specifies a program that can be built.  Adequacy—The SAD specifies a program that will satisfy its requirements.  Well-Formedness—The notations in the SAD are used correctly.

© 2007 Pearson Education, Inc. Publishing as Pearson Addison-Wesley 5 SAD Quality Characteristics 2  Completeness—The SAD includes all required sections; contains models needed to explain the design; and specifies all important component characteristics, relationships, interactions, etc.  Clarity—The SAD is understandable to someone familiar with the problem and notations.  Consistency—A single program can satisfy the specifications in the SAD.

© 2007 Pearson Education, Inc. Publishing as Pearson Addison-Wesley 6 Reviews A review is an examination and evaluation of a work product or process by a team of qualified individuals.

© 2007 Pearson Education, Inc. Publishing as Pearson Addison-Wesley 7 Types of Reviews  Desk Check—An assessment of a design by the designer  Walkthrough—An informal presentation to a team of designers  Inspection—A formal review by a trained inspection team  Audit—A review conducted by experts from outside the design team  Active Review—An examination by experts who answer specific questions about the design

© 2007 Pearson Education, Inc. Publishing as Pearson Addison-Wesley 8 An Architecture Inspection Checklist  The notations used for each model are correct.  Every required section of the SAD is present.  The SAD specifies the program’s main components.  The SAD specifies the states and state transitions for all components with important states.  The SAD specifies important or complex component collaborations.  The SAD specifies each component’s responsibilities.  The SAD specifies each component’s interface.  The SAD specifies each component’s important properties.  The SAD specifies each component’s important relationships to other components.  The SAD clearly states the connections between different architectural models.  The SAD states the rationale for all important design decisions.  Each design rationale states the problem to be solved and the constraints on the designer.  Each design rationale summarizes the major design alternatives and their evaluations.  Each design rationale explains why the final design was selected.  All specifications are clear.  No specification contradicts any other specification in the SAD.

© 2007 Pearson Education, Inc. Publishing as Pearson Addison-Wesley 9 Active Design Reviews  Remedies problems with traditional reviews Lack of expertise Cursory reviews  Forces reviewers to engage the document in their areas of expertise by asking them to answer specific questions about design details

© 2007 Pearson Education, Inc. Publishing as Pearson Addison-Wesley 10 Active Design Review Process

© 2007 Pearson Education, Inc. Publishing as Pearson Addison-Wesley 11 Review Preparation  Identify Review Goals—Designers choose aspects of the design they want checked.  Choose Reviewers—Designers identify two to four qualified reviewers and obtain their consent to do the review.  Create Questions—Designers formulate questions to be answered by reviewers. Force reviewers to understand the design Ask reviewers to solve problems, explain something, etc.

© 2007 Pearson Education, Inc. Publishing as Pearson Addison-Wesley 12 Review Performance  Hold an Overview Meeting—Designers sketch the architecture, explain the process, set deadlines, etc.  Do Reviews—The reviewers do their reviews on their own. May meet with designers are send s to get clarification, explanations, etc. Deliver their results when complete

© 2007 Pearson Education, Inc. Publishing as Pearson Addison-Wesley 13 Review Completion  Study Reviews—Designers study the review results. May meet with reviewers or questions

© 2007 Pearson Education, Inc. Publishing as Pearson Addison-Wesley 14 Continuous Review  The sooner a defect is fixed, the cheaper it is to fix.  Reviews must be done when design artifacts are complete as a final quality check.  Reviews should also be done during the design process to catch defects as soon as possible.  Different kinds of reviews are appropriate at different stages of the process (discuss).

© 2007 Pearson Education, Inc. Publishing as Pearson Addison-Wesley 15 Summary  A SAD should be reviewed when substantially complete to ensure that it Specifies a feasible and adequate architecture; Has well-formed models; and Is complete, clear, and consistent.  Various sorts of reviews can be used.  An effective form of review is the active review.  Reviews should be done when artifacts are complete and also throughout the design process.