Software Engineering 1 Object-oriented Analysis and Design Chap 24 Iteration 2 More Patterns

Software Engineering 2 Object-oriented Analysis and Design From Iteration 1 to 2  When iteration-1 ends, the following should be accomplished: m All the software has been tested: unit, acceptance, load, usability, and so on. m The idea in the UP is to do early, realistic, and continuous verification of quality and correctness, so that early feedback guides the developers to adapt and improve the system. m Customers have been regularly engaged in evaluating the partial system, to obtain feedback for adaptation and clarification of requirements. m The system, across all subsystems, has been completely integrated and stabilized as a baselined internal release.

Software Engineering 3 Object-oriented Analysis and Design From Iteration 1 to 2  Some activities also be included m An iteration planning meeting to decide what to work on in the next iteration, resolve questions, and identify major tasks. m The start of the new iteration, use a UML tool to reverse engineer diagrams from the source code of the last iteration (the results are part of Design Model). m to illustrate the starting point of the logical design for the next iteration. m Usability analysis and engineering for the UI is underway. m Database modeling and implementation is underway. m Another two-day (for example) requirements workshop occurs, and more use cases are written in their fully dressed format.  During elaboration, while perhaps 10% of the most risky requirements are being designed and implemented, there is a parallel activity to deeply explore and define perhaps 80% of the use cases for the system. m Participants include developers/architect from the first iteration, so that the investigation and questioning during this workshop is informed from the insights gained from actually quickly building some software.

Software Engineering 4 Object-oriented Analysis and Design Iteration-2 Requirements and Emphasis: Object Design and Patterns 1  For case studies iteration-2 ignores requirements analysis and domain analysis, and focuses on object design with responsibilities and GRASP, and applying some GoF design patterns.  Iteration-2 of the NextGen POS application handles several interesting requirements: m Support for variations in third-party external services. For example, different tax calculators must be connectable to the system, and each has a unique interface. m Complex pricing rules. m A design to refresh a GUI window when the sale total changes.  These interesting requirements may be identified during inception. (e.g., the Process Sale use case indicates the pricing problem)

Software Engineering 5 Object-oriented Analysis and Design Iteration-2 Requirements and Emphasis: Object Design and Patterns 2  Main Success Scenario of Process Sale use case : m 1.Customer arrives at a POS checkout with goods and/or services to purchase. m 2.Cashier tells System to create a new sale. m 3.Cashier enters item identifier. m 4.System records sale line item and presents item description, price, and running total. Price calculated from a set of price rules. m...  Supplementary Specification record details of the domain rules for pricing, and indicate the need to support varying external systems.

Software Engineering 6 Object-oriented Analysis and Design Iteration-2 Requirements and Emphasis: Object Design and Patterns 3... Senior15% off. Preferred Customer10% off. Each retailer uses different rules.Employee20% off. Retailer policy.High.Purchaser discount rules.RULE4 SourceChangeabilityRuleID  Supplementary Specification m... m Interfaces m Software Interfaces m For most external collaborating systems (tax calculator, accounting, inventory,... ) we need to be able to plug in varying systems and thus varying interfaces. m... m Domain (Business) Rules

Software Engineering 7 Object-oriented Analysis and Design Iteration-2 Requirements and Emphasis: Object Design and Patterns 4  Supplementary Specification m Information in Domains of Interest m Pricing m In addition to the pricing rules described in the domain rules section, note that products have an original price, and optionally a permanent markdown price. A product's price (before further discounts) is the permanent markdown price, if present. Organizations maintain the original price even if there is a permanent markdown price, for accounting and tax reasons. m...

Software Engineering 8 Object-oriented Analysis and Design Iteration-2 Requirements and Emphasis: Object Design and Patterns 5  Incremental Development for a Use Case Across Iterations m Because of these requirements, we are revisiting the Process Sale use case in iteration-2, but implementing more scenarios. m It is common to work on varying scenarios or features of the same use case over several iterations and gradually extend the system to ultimately handle all the functionality required. m Short, simple use cases may be completely implemented within one iteration. m One scenario should not be split across iterations; an iteration should complete one or more end-to-end scenarios. m Iteration-1 made simplifications so that the problem and solution were not overly complex to explore.