A (Web) Service-Oriented Approach to Teaching CS/IS1

Billy Lim, Bryan Hosack, Paul VogtSchool of Information Technology

Illinois State University

INTRODUCTIONSProject Personnel

Workshop Participants

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Schedule

• Project Overview/Experience Report (9:00-10:15am)• Hands-On Exercises (10:30am-12:00pm)• Lunch (12:00-1:00pm)• Assignment Development (1:00-2:30pm)• Discussion /Feedback (2:45-4:00pm)

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Workshop Objectives

1. Disseminate the use of service-oriented approach to teaching CS1/IS1

2. Explore educational innovations for indoctrinating students the state-of-the-art software development practices using SOA

3. Build a learning/research community of service-orientation-in-CS1/IS1 enthusiasts.

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Project Overview

• Began with: – "On Integrating Web Services from the Ground Up into

CS1/CS2," ACM SIGCSE 2005, St. Louis, MO, Feb., 2005. • Now supported by:

– NSF-DUE-CCLI-0837056, "Integrating Service-Oriented Paradigm into Introductory Information Technology Curricula," 2009 – 2011.

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Basic Ideas

• SOA/Web services have gained popularity in many industries and in upper division/graduate CS/IS curricula

• Why not introduce service-orientation earlier in the curriculum?– Service-orientation can make a course more interesting– Service-orientation can better prepare students for upper

division classes and for the industry upon graduation– Service-orientation can introduce sound principles of

software engineering earlier in the curriculum

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Courseware Showcase

• Main project site:– http://www.itk.ilstu.edu/ws4intro

• The site contains info on:– PowerPoint slides– Lab exercises– Programming assignments– Tutorials– List of Web services used

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Experience Report• Outcome 1: Students will provide a better evaluation of

the IT1 course by 10% as compared to traditional IT1 course evaluations. Students will also indicate a positive perception of the SOA/Web services learning experience.

• Outcome 2: Student course grade performance will increase in the IT1 course by 10% as compared to traditional IT1 course performance.

• Outcome 3: Employers of computer science and information technology students will indicate a positive response to an SOA/Web services centered curriculum.

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Experience Report (cont’d)

• Outcome 1: Limited data…partial support– In hindsight we should have chosen a different

measure– The amount of data collected will be limited and

probably won’t be statistically significant

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Experience Report (cont’d)

• Outcome 2: Demographics– 99 students (missing cases were mostly drops)– 34% in WS/SOA section– 12% of the students were female, 88% male– 76% unable to define “What is a WS?” to 88% could

define

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Experience Report (cont’d)

• Outcome 2: Statistically significant improvement in final exam performance and course grade

Final Exam Regression Coefficientsa

Model

Unstandardized CoefficientsStandardized Coefficients

t Sig.

95% Confidence Interval for B

B Std. Error Beta Lower Bound Upper Bound1 (Constant) 12.585 9.105 1.382 .170 -5.494 30.663

Female1 -15.298 6.755 -.166 -2.265 .026 -28.709 -1.886

Class .443 2.346 .014 .189 .851 -4.216 5.101

Tradl1 -11.483 4.669 -.181 -2.459 .016 -20.753 -2.212

CumGPA 23.071 2.524 .662 9.141 .000 18.060 28.083

a. Dependent Variable: FinlExm, Adj R-Squared .493

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Experience Report (cont’d)

• Outcome 2: Statistically significant improvement in course grade

Final Grade Regression Coefficientsa

Model

Unstandardized CoefficientsStandardized Coefficients

t Sig.

95% Confidence Interval for B

B Std. Error Beta Lower Bound Upper Bound1 (Constant) -.515 .338 -1.523 .131 -1.187 .157

Female1 -.673 .251 -.155 -2.682 .009 -1.171 -.175

Class -.192 .087 -.130 -2.207 .030 -.365 -.019

Tradl1 -.456 .173 -.153 -2.630 .010 -.801 -.112

CumGPA 1.325 .094 .807 14.126 .000 1.139 1.511

a. Dependent Variable: GradeAdj R-Squared = .684

Experience Report (cont’d)

Outcome 2: Grading bias and other concerns• Tukey Pairwise Comparison’s

were not significant for the instructors, except for one pairing. This pairing did not include either of the instructor’s teaching the web service sections.

• More data will help alleviate concerns about the grading

Mean Grades Awarded

N Mean Std. Deviation1 127 1.94 1.305

2 39 2.46 1.570

3 15 3.13 1.060

4 3 2.33 2.082

5 36 2.67 1.242

6 65 2.54 1.251

7 36 2.28 1.466

8 10 2.70 1.636

9 27 2.78 1.219

10 10 1.50 1.509

Total 368 2.33 1.376

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Experience Report (cont’d)

• Outcome 3: Employers of computer science and information technology students will indicate a positive response to an SOA/Web services centered curriculum. – Survey developed (see handout)– Companies contacted/to contact: Amazon, Google,

State Farm (other local users), suggestions…

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Experience Report (cont’d)

• Continued interest in students after the completion of the class

• Initial frustration translates to positive response when creating “real-world”-like applications

• Engaging experience for faculty

• Second semester syndrome

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Experience Report (cont’d)

• “Do I have to code this? Isn’t there a Web service to do that?”– A student’s comment on the requirement to “validate … the

state’s 2-letter abbreviation (must be one of the 50 state abbreviations).”

• “But that’s just calling the Web service to get a word from the dictionary, right?”– A student’s remark on needing to handle the part of the

assignment that requires them to hit a Web service to randomly generate a word (after he has already completed the part where he provides his own word) in the Hangman program.

Session 2: Web services in CS1/IS1

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Reusable Components

• Most programs are created by combining components that exist already, not from scratch!

• Reusing components saves time and money.

• Reused components are likely to be better developed, and more reliable.

• New components should be designed to be reusable by other applications.Don’t reinvent the wheels!

Source: Savitch & Carrano 2009 CS1 text

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Software Reuse

Package names

Class names

Description of class Scanner

Source: Savitch & Carrano 2009 CS1 text

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Software Reuse via SOA/WS

• Latest form of reuse is via “services”• SOA (Service-Oriented Architecture)

– “A system for linking resources on demand. In an SOA, resources are made available to other participants in the network as independent services that are accessed in a standardized way. This provides for more flexible loose coupling of resources than in traditional systems architectures.” –Sybase

– “Architecture that describes an entity (e.g., application or enterprise) as a set of interdependent services. SOA provides for reuse of existing services and the rapid deployment of new business capabilities based on existing assets.” -- CIO.gov

– Many others …

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Software Reuse via SOA/WS

• One popular way of implementing SOA is via Web services• WS (Web Service)

– "a software system designed to support interoperable machine-to-machine interaction over a network. It has an interface described in a machine-processable format (specifically WSDL). Other systems interact with the Web service in a manner prescribed by its description using SOAP-messages, typically conveyed using HTTP with an XML serialization in conjunction with other Web-related standards.“ – W3C

– Laymen terms: a piece of program that can interact with another program using standardized Web protocols

– Examples: Google Maps API, Flickr API, Twitter API, Amazon Web services. (API = Application Programming Interface)

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NetBeans Generated Code Templatetry { // Call Web Service Operation <someService> service = new <someService>; < someServicePort> port = service.get<someServicePort>(); // TODO initialize WS operation arguments here declarations of arguments here // TODO process result here <someResult> result = port.methodOfInterest(argument list); System.out.println("Result = "+result);} catch (Exception ex) { // TODO handle custom exceptions here}

Bold: Statements of interests; Wish Exception ex wasprinted as part of the template.

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Decision Structure try { // Call Web Service Operation com.cdyne.ws.profanityws.profanity.Profanity service = new com.cdyne.ws.profanityws.profanity.Profanity(); com.cdyne.ws.profanityws.profanity.ProfanitySoap port = service.getProfanitySoap(); // TODO initialize WS operation arguments here java.lang.String text = “You smoked weed? Dumb!"; // TODO process result here com.cdyne.ws.profanityws.profanity.FilterReturn result = port.simpleProfanityFilter(text); if (result.isFoundProfanity())

… else

… } catch (Exception ex) { // TODO handle custom exceptions here }

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Repetition Structuremypackage.ISUDirectoryLookUpService service = new mypackage.ISUDirectoryLookUpService();mypackage.ISUDirectoryLookUp port = service.getISUDirectoryLookUpPort();// TODO initialize WS operation arguments herejava.lang.String lastName = aLastName;java.lang.String firstName = "";java.lang.String city = "";java.lang.String state = "";java.lang.String zip = "";// TODO process result heremypackage.DirectoryResult result = port.findPerson(lastName, firstName, city, state, zip);

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Repetition Structure (2)Int listingSize = result.getItems().getDirectoryRecord().size();for (int i = 0; i < listingSize; i++) { firstName = result.getItems().getDirectoryRecord().get(i).getFirstName(); lastName = result.getItems().getDirectoryRecord().get(i).getLastName(); zip = result.getItems().getDirectoryRecord().get(i).getZip(); phone = result.getItems().getDirectoryRecord().get(i).getPhone(); state = result.getItems().getDirectoryRecord().get(i).getState(); cityNamePrint = result.getItems().getDirectoryRecord().get(i).getCity();}

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Hands-on Activities

• http://r2d2.itk.ilstu.edu/ws4intro/wordpress/?page_id=295

Session 3: Curriculum Development in CS1/IS1

http://r2d2.itk.ilstu.edu/ws4intro/wordpress/?page_id=308

Session 4: The Future of Web services in CS1/IS1 (and CS2/IS2?)

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Group Discussion Topics

• Phase II objectives?

• Viability of the current curriculum in other academic institutions?

• Synthesis across the curriculum?

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Please tell us what you think!

and

THANK YOU FOR ATTENDING!

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