Referee Scheduler CIS 758 Blue Elephant Tony DiCola Mauktik Gandhi Jeff Mathew Tim McConnell Todd Sahl Eugene Talagrand

Presentation Outline Product Demonstration / Overview Functional Requirements Intro Non-Functional Requirements Intro Process Intro Non-Functional Requirements in Detail  Traceability through Design, Arch., Impl.

Product Demo Let’s check it out

Requirements Overview C Core Functionality U Usability P Performance S Security S Supportability Non-FunctionalRequirements FunctionalRequirements

Main Use Case  Allowing Referees to Schedule Online Main Additional Functional Req.  Security – No Unauthorized Browsing CSSPU CS

Core Non-Functional Reqs Usability  Easy to Learn to Use Supportability  Easy to Learn to Program Performance  Speedy Enough Under Concurrent Load SPU

Process Intro Lightweight RUP, ala Craig Larman  Step-by-Step OOAD  Inception, Elaboration Bounded Iterations New Methodology, Martin Fowler  Adaptive, People Oriented Rapid UI Prototyping w/ Feedback T-Model, Middleware Technologies  From J2EE Best Practices Article

T Model by Middleware Co.

Metrics? Fowler: Product of Manufacturing Optimization Ramnath: Do It Please Blue Elephant: We Tried  Timesheets  Hard to Keep Up With

Metrics: Results Anecdotal Results:  Productivity Increased as: Configuration Management Settled Down  Initial Problems: Eclipse Tomcat Hibernate, MySQL Struts Members Became Familiar with Core Architecture – MVC, Struts, JSP, JSTL

Core Architecture - MVC

MVC Continued

Transactions

Transactions contd.

Concurrency Transient vs. Persistent Objects Optimistic Locking  Built in Support in Hibernate  Finer Grain Control Available with Custom Code

Security - Requirements Access to registered users only  Prevent public browsing Access control and Roles  Referees vs. Administrators Password Security  Encrypted passwords in database  notification when password changes CSSPU

Security - Architecture User class hierarchy  Hibernate mapping  Access Control Filter  Logical Paths  Tomcat Roles ? CSSPU

Security - Architecture Password Service  SHA1 – One-way encryption function  Random password Generation Service  Java Mailing API CSSPU

Usability - Requirements No End User Training Possible Successful Adoption Hinges on Transparent Usability End Users are not Computer Experts Accessibility CSSPU

Usability - Design Transparent Navigation  Shallow Information Hierarchy  Tabbed Interface  Clear, Consistent Page Sections  Consistent Placement of Feedback CSSPU

Usability – Design Continued Task Oriented Design  Minimal Text & Images, No ‘Happy Talk’  Built In Help  JavaScript Validation of Input Accessibility  Text-Only Browser Support  Minimal Browser Dependency CSSPU

Usability Architecture & Impl. Common, Ubiquitous Technologies  Server Pages, JavaScript, CSS Focus on Architecture Extensibility  Templating, Page Composition Used Standardized Libraries  JSTL - Simpler Language, Easier for Page Designers CSSPU

Usability Process Iterative Prototype  Broad and Shallow  Little or No Functionality  Feedback From Clients and Users CSSPU

Supportability Requirements Extensibility  Additional Use Cases to be Implemented  Requirements Change Over Time Maintainability  Future Maintenance Programmers Need to Understand Architecture, Code Configurability CSSPU

Supportability Design Separation of Concerns into Tiers  Presentation Layer  Workflow Layer  Business Delegate Layer  Domain Model Layer  Data Access Object Layer  Data Source Layer CSSPU

Supportability Design Contd. Separation of Concerns into Tiers  Decoupling of Components of Application Limits Effect of Change in one area Makes Code Easier to Comprehend Allows Parallel Development via Interfaces CSSPU

Supportability Design Contd. Documentation of Design  Short Papers on Technologies / Design Patterns  Use Case Diagrams / Sequence Diagrams  Pointers to Good Resources  Doxygen API Documentation CSSPU

Supportability Architecture Strict Adherence to MVC Pattern Use of Popular Frameworks  Workflow by Struts  Persistence by Hibernate Configurability  Strategy Patterns  Externalized Strings CSSPU

Supportability - Process Incremental Refactorings  Refactored Packages  Page Composition  Externalized Strings  Class Based CSS Design CSSPU

Performance - Requirements Thousands of Games and Users During Initial Sign-Up Period, Several Hundred Concurrent Users  Site Must Remain Usable and Responsive under Load CSSPU

Performance – Design Cont. Presentation Layer: XSL-T was used for the first 4 Weeks  Provides Extensibility, but very Computationally Intensive JSP/JSTL Refactoring One Week of Performance Testing CSSPU

Performance – Design Cont. Keeping Games in Memory  Required 300 MB of RAM for 300 users Client Side Sorting, Filtering of Conflicting Games Offloaded to User to Reduce Server Load  Optimized Primary Database Query Trade-off between memory, CPU and Database performance CSSPU

Performance - Process Speed of Main Use Case always considered Refactored Session cache design CSSPU