2.7 Perspectives

2.7.1 Highlights

  • Reduction of total cost of ownership and easier integration with partners and legacy systems are the key business drivers for Web Services.

  • Web Services is gaining more momentum in industry implementation and has wider vendor support.

  • There are early success stories of Web Services implementation.

  • There are a few ways to present a business case to implement Web Services, but they must be put in the context of the future (long- term benefits, non-quantitative benefits) and reusability, not one-off development costs.

2.7.2 Best Practices and Pitfalls

The following are some ideas regarding establishing a business case for Web Services implementation.

Best Practices

  • When presenting a Web Services business case, always present both the short-term and long-term benefits.

  • Compare alternatives with risk mitigation.

  • Cite scenarios showing how your company can make use of Web Services. Remember to bring Use Case Studies as part of your story.

Pitfalls

  • Do not quantify ROI for the business case ”it is too early to see the result. Using hard figures too early will not win the confidence of your business audience.

  • Do not start the business case with Web Services technology details. Business audiences do not like a business case for technology's sake.

2.7.3 Paper and Pencil

Objective

Invoking Web Services can be very easy. The objective of this exercise is to learn how to invoke a public Web Service (with a Web Services Description Language) using a rich client (non-Java) and a Java client, respectively.

Exercise

The following site: http://www.xmethods.net/sd/2001/CurrencyExchangeService.wsdl contains a service definition for a currency exchange service provided by xmethods.net. Write a rich client to invoke the remote Web Service. You may develop a Java client or a SOAP-Lite client. A Java sample program is available from http://www.xmethods.net/download/servicefiles/CurrencyClient.java . You can download SOAP-Lite from http://www.soaplite.com .

Procedures for Java Client

You need to install and configure your J2SE SDK with CLASSPATH and PATH set. Refer to Appendix C in this book for details. Download the CurrencyClient.java and save a local copy. Execute the following commands to compile and execute the client program (see Figure 2-9):

Figure 2-9 Invoking a public Web Service with Java client
 D:\Dev\mydemo>  javac CurrencyClient.java  D:\Dev\mydemo>  java CurrencyClient  34.19 

The CurrencyClient.java program will invoke the currency exchange service at http://services.xmethods.com:80/soap . It specifies the sell/buy cross-currency pair United States to Taiwan, which returns the spot rate US$1 = 34.19 Taiwan yen.

Procedures for SOAP-Lite Client

You need to install and configure SOAP-Lite with Perl 5.0 or higher with PATH pointing to the Perl 5.x distribution. Refer to Appendix C for details.

The sample SOAP-Lite client is shown in Figure 2-10. You only need to specify the "service" with the WSDL, and the operation name (that is, getRate) with the input parameters. The result is shown in Figure 2-11.

Figure 2-10 Sample SOAP-Lite Client Code
 #!perl -w #!d:\perl\bin\perl.exe BEGIN { warn "Invoking a public FX Web Services...\n" } # import interface. All methods from loaded service are imported by default use SOAP::Lite    service =>  'http://www.xmethods.net/sd/2001/CurrencyExchangeService.wsdl',  ; warn "Loaded...\n"; print  getRate('us', 'taiwan'),  "\n"; 

Execute the SOAP-Lite program just like any Perl script. This should render the same result as the Java client for the sell/buy currency pair United States to Taiwan.

Figure 2-11 Invoking a Public Web Service with SOAP-Lite Client
 D:\Dev\mydemo>  perl myCurrencyRate.pl  Invoking a public FX Web Services... Loaded... 34.19 

2.7.4 References

Web Services Trends

John Hagel III and John Seely Brown. "Your Next IT Strategy." Harvard Business Review , October 2001.

Web Services Case Studies

David Chappell and Tyler Jewell. Java Web Services. (California: O'Reilly, 2002).

Anton Fricko. " Tasting SOAP ”Project Experience with Web Services ." IBM developerWorks Live! Conference 2002 .

Tim Hilgenberg and John A. Hansen. " Building a Highly Robust, Secure Web Services Conference Architecture to Process 4 Million Transactions per Day ." IBM developerWorks Live! Conference 2002

IDC. "People's Insurance Company of China: eBusiness Portal Attracts New Customers and Reduces Costs." http://www.sun.com/service/about/success/recent/picc.html

Chris Nelson. " Web Services Real Enterprise Usage ." IBM developerWorks Live! Conference 2002.

Trans-Canada (TCPL). http://www.infoworld.com/articles/hn/xml/02/03/18/020318hnspine.xml

Kevin Yin. " A Reference Architecture for Smart Web Service ." August 17, 2001. http://dcb.sun.com/practices/devnotebook/webserv_refarch.jsp

Ezra Zask, ed. The e-Finance Report . New York: Wiley, 2001.

Grid Computing and Web Services

Global Grid Forum. http://www.gridforum.org/ogsi-wg/drafts/draft-ggf-ogsi-gridservice-23_2003-02-17.pdf

The Globus Project. http://www.globus.org/research/papers.html#OverviewPapers

The Securities Industry Middleware Council. " The Future of Middleware: Grid Computing and Web Services ." November 19, 2002, General Meeting. http://www.simc-inc.org/archive0203/Grid/agenda19nov2002.htm

Tom Sullivan. "Sun Combines Grid Computing, Web Services." http://www.infoworld.com/article/02/02/15/020215hnsunonegrid_1.html

Liang-Jie Zhang, Jen-Yao Chung, and Qun Zhou. " Developing Grid computing applications, Part 1 ." http://www-106.ibm.com/developerworks/ webservices /library/ws-grid1/

Liang-Jie Zhang, Jen-Yao Chung, and Qun Zhou. " Developing Grid computing applications, Part 2 ." http://www-106.ibm.com/developerworks/webservices/library/ws-grid2/

Other References

White label service using Web Services (i-Deal). http://www.lighthouse-partners.com/wallstreettng/presentations/Frank%20LaQuinta.ppt



J2EE Platform Web Services
J2EE Platform Web Services
ISBN: 0131014021
EAN: 2147483647
Year: 2002
Pages: 127
Authors: Ray Lai

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