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(c) 2010 University of California, Irvine – André van der Hoek

Informatics 122 Software Design II. Lecture 9 André van der Hoek & Alex Baker Duplication of course material for any commercial purpose without the explicit written permission of the professor is prohibited. February 21, 2010 – 18:05:18.

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(c) 2010 University of California, Irvine – André van der Hoek

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  1. Informatics 122Software Design II Lecture 9 André van der Hoek & Alex Baker Duplication of course material for any commercial purpose without the explicit written permission of the professor is prohibited. February 21, 2010 – 18:05:18 (c) 2010 University of California, Irvine – André van der Hoek 1

  2. Today’s Lecture • Component reuse • Assignment 5 February 21, 2010 – 18:05:18 (c) 2010 University of California, Irvine – André van der Hoek 2

  3. build(and thus design) buy or get for free(and thus fit into a design) A Critical Design Tradeoff February 21, 2010 – 18:05:18 (c) 2010 University of California, Irvine – André van der Hoek 3

  4. build(and thus design) buy or get for free(and thus fit into a design) A Critical Design Tradeoff: Benefits full control full understandingflexibilitycompetitive advantage can be instantaneousexternal support quality February 21, 2010 – 18:05:18 (c) 2010 University of California, Irvine – André van der Hoek 4

  5. build(and thus design) buy or get for free(and thus fit into a design) A Critical Design Tradeoff: Drawbacks timecost maintenancestandards licensinglack of customizabilityobsolescenceurgent bugs evaluation cost February 21, 2010 – 18:05:18 (c) 2010 University of California, Irvine – André van der Hoek 5

  6. build(and thus design) buy or get for free(and thus fit into a design) A Critical Design Tradeoff can be instantaneousexternal support quality full control full understandingflexibilitycompetitive advantage timecost maintenancestandards licensinglack of customizabilityobsolescenceurgent bugsevaluation cost February 21, 2010 – 18:05:18 (c) 2010 University of California, Irvine – André van der Hoek 6

  7. build(and thus design) buy or get for free(and thus fit into a design) Our Focus Today can be instantaneousexternal support quality full control full understandingflexibilitycompetitive advantage timecost maintenancestandards licensinglack of customizabilityobsolescenceurgent bugsevaluation cost February 21, 2010 – 18:05:18 (c) 2010 University of California, Irvine – André van der Hoek 7

  8. A New Kind of Design Decision • Less fine control • More learning and using and applying • Similar to recovery February 21, 2010 – 18:05:18 (c) 2010 University of California, Irvine – André van der Hoek 8

  9. Architectural Mismatch • Architectural mismatch stems from mismatched assumptions a reusable component makes about the system structure of which it is to be part • Components • functionality • interfaces • behavior • control model • Connectors • protocols • data model • System topology • Construction • dependencies • initialization Difficult to predict a-priori February 21, 2010 – 18:05:18 (c) 2010 University of California, Irvine – André van der Hoek 9

  10. Architectural Mismatch • Architectural mismatch stems from mismatched assumptions a reusable component makes about the system structure of which it is to be part • Components • functionality • interfaces • behavior • control model • Connectors • protocols • data model • System topology • Construction • dependencies • initialization How much adaptation is too much adaptation? February 21, 2010 – 18:05:18 (c) 2010 University of California, Irvine – André van der Hoek 10

  11. identifypreliminaryarchitecture identifypotentialplaces forreuse establishselectioncriteria (perplace) Component Reuse Process updatearchitecture selectcomponent evaluatecomponents search forapplicablecomponents February 21, 2010 – 18:05:18 (c) 2010 University of California, Irvine – André van der Hoek 11

  12. Identify Preliminary Architecture • Largely as usual • Familiarity with certain reusable components may influence the architectural choices being made February 21, 2010 – 18:05:18 (c) 2010 University of California, Irvine – André van der Hoek 12

  13. Identify Potential Places for Reuse • There are components for just about anything • graph layout • database access • regular expression handling • numerical computing • protein visualization • speech recognition • e-mail handling • index and search • maps • geocoding • … • Judiciously mark the architecture in terms of where reusable components may fit in February 21, 2010 – 18:05:18 (c) 2010 University of California, Irvine – André van der Hoek 13

  14. Establish Selection Criteria (Per Place) • What kind of component does the architecture really need? • functionality • absolutely necessary versus desired functionality • software qualities • How is the component to fit with the rest of the architecture? • some adaptation can be accommodated • Investment • cost • future cost • Reputation • component provider • component itself • … February 21, 2010 – 18:05:18 (c) 2010 University of California, Irvine – André van der Hoek 14

  15. Search for Applicable Components • Google is a wonderful thing • www.google.com • code.google.com • Component repositories • rich in available components • many junk • some decent • occasional gems • Research and professional development literature • Too many is no good • Too few is no good either • although one perfect component would solve the problem February 21, 2010 – 18:05:18 (c) 2010 University of California, Irvine – André van der Hoek 15

  16. sourceforge.net February 21, 2010 – 18:05:18 (c) 2010 University of California, Irvine – André van der Hoek 16

  17. apache.org February 21, 2010 – 18:05:19 (c) 2010 University of California, Irvine – André van der Hoek 17

  18. Evaluate Components • Apply selection criteria to each of the components found • beware of the platform, deployment needs, licensing terms • matrix of criteria versus components • Additional approaches • trial / evaluation licenses • reading component code • examine sample programs using the component • writing code using the component • Examine the component’s documentation • Analyze architectural impact of the component • Perhaps even “mini integrate” the component February 21, 2010 – 18:05:19 (c) 2010 University of California, Irvine – André van der Hoek 18

  19. Select Component • Choose the optimum component • understand tradeoffs • be prepared to not choose a component February 21, 2010 – 18:05:19 (c) 2010 University of California, Irvine – André van der Hoek 19

  20. Update Architecture • Design any adapters necessary to fit the component • Redesign other components as needed • Restructure architecture as needed • Consider implementers • special role for documentation February 21, 2010 – 18:05:19 (c) 2010 University of California, Irvine – André van der Hoek 20

  21. A Quick Sample Among the Graduate Students • Xalan • Xerces • Lucene • Jung • Kaffe • Bcel • Equip • JLoox • Schematron • GraphViz • Jython • Scriptalicious • … • Xacml • SWT • JOAL • Jetty • Batik • JmDNS • Darwin Streaming Server • Spook • Mplayer • MySQL • live.com RTP/RTSP • gaim im client • … February 21, 2010 – 18:05:19 (c) 2010 University of California, Irvine – André van der Hoek 21

  22. Assignment 5 • Research available components that provide a particular kind of functionality for Calico, set up selection criteria, make a choice of the component that you believe is best, and detail how you would go about integrating the component • Specifically, research components for the following situations • speech recognition – we want to add the ability to use speech to create text labels, for which we need some sort of speech-to-text conversion component that is as reliable as possible • mouse gestures – we would like to integrate more complex mouse gestures; find an existing component that can recognize mouse gestures reliably, possibly employing a learning algorithm • graphics – we want to replace Piccolo, as it is no longer supported, ideally with a drawing framework that has powerful functionality for future extensions yet has minimal impact on the current architecture • distribution – we would like to replace the current home-grown mechanism with an actual real protocol and middleware that is lightweight, fast, and can handle long distance February 21, 2010 – 18:05:19 (c) 2010 University of California, Irvine – André van der Hoek 22

  23. Assignment 5 • Additional constraint • we have $25,000 in funds to spend on this project, but we want to save money for user studies and other assorted expenses, so cost should be (somewhat) minimized • if truly warranted, management can be requested to fund one “big ticket” component, up to possibly $75,000 February 21, 2010 – 18:05:19 (c) 2010 University of California, Irvine – André van der Hoek 23

  24. Assignment 5 • Create a 10 minute presentation that describes for one of the four categories (specific assignments of which category by which team on slide 26) • your search process • candidate components you considered • strengths • weaknesses • your selection criteria • the component you deem best (and why) • Create a document that describes, at the design and code level, the impact of incorporating the chosen components (all four) • from this document, someone should be able to make these changes “effortlessly” February 21, 2010 – 18:05:19 (c) 2010 University of California, Irvine – André van der Hoek 24

  25. Assignment 5 • Presentation in class Thursday, February 25th • Document due at the beginning of class Thursday, February 25th • Graded on breadth and depth of component evaluation, as well as the thoroughness and insightfulness of the document • Each person also needs to submit a team evaluation (new forms available on class webpage) February 21, 2010 – 18:05:19 (c) 2010 University of California, Irvine – André van der Hoek 25

  26. Team Assignments • Team 1 (speech) • ZIMING DAI • RYAN CHRISTOPHER HSU • SEAN LEW TSUSAKI • KYLE STEPHEN LUTZE • JAMES RICHARD BENSON Team 2 (mouse) • TAE SUNG KIM • JORDANIEL CHARLES WOLK • ARREN APPLEBAUM • SOHRAB HEJAZI • GARRETT KIM Team 3 (graphics) • RYAN SCOTT NISSENBAUM • STACEY THUY VI DAO • HUNTER GLENN GILLANE • ALEX RYAN CHUNG • MATTHEW JAMES PALMER • Team 4 (distibution) • SAMUEL JAMES KAUFMAN • KYLE PHILLIP MUSLER • PATRICK CHAO-CHENG LU • JOSHUA ALEXANDER PAPA • JESSE MAYORGA DANIELSON Team 5 (graphics) • LEO ZEN • FRANCISCO MORALES • HIROE ONO • SIMON HUYNH • FRANCESCO MANTOVANI • MICHAEL IDRIS MERCHANT February 21, 2010 – 18:05:19 (c) 2010 University of California, Irvine – André van der Hoek 26

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