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:Devmydemo>javac CurrencyClient.java D:Devmydemo>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:perlinperl.exe
BEGIN { warn "Invoking a public FX Web Services...
" }
# 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...
";
print getRate('us', 'taiwan'), "
";
|
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:Devmydemo>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.
37The Web Services Phenomenon and Emerging Trends 37 References Bibliography Web Services Trends [ch02biblio01div01entry01] John Hagel III and John Seely Brown "Your Next IT Strategy " Harvard Business Review October 2001 Web Services Case Studies [ch02biblio01div02entry01] David Chappell and Tyler Jewell Java Web Services California O Reilly 2002 [ch02biblio01div02entry02] Anton Fricko " Tasting SOAP--Project Experience with Web Serv ices " IBM developerWorks Live! Conference 2002 [ch02biblio01div02entry03] 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 [ch02biblio01div02entry04] 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 [ch02biblio01div02entry05] Chris Nelson " Web Services Real Enterprise Usage " IBM developer Works Live! Conference 2002 [ch02biblio01div02entry06] Trans Canada TCPL http //www infoworld com/articles/hn/xml/ 02/03/18/020318hnspine xml [ch02biblio01div02entry07] Kevin Yin " A Reference Architecture for Smart Web Service " August 17 2001 http //dcb sun com/practices/devnotebook/webserv_refarch jsp
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
38The Web Services Phenomenon and Emerging Trends [ch02biblio01div02entry08] EzraZask ed The e Finance Report New York Wiley 2001 38 Grid Computing and Web Services [ch02biblio01div03entry01] Global Grid Forum http //www gridforum org/ogsi wg/drafts/draft ggf ogsi gridservice 23_2003 02 17 pdf pers html#OverviewPapers [ch02biblio01div03entry02] The Globus Project http //www globus org/research/pa [ch02biblio01div03entry03] 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 [ch02biblio01div03entry04] Tom Sullivan "Sun Combines Grid Computing Web Services " http // www infoworld com/article/02/02/15/020215hnsunonegrid_1 html [ch02biblio01div03entry05] Liang Jie Zhang Jen Yao Chung and Qun Zhou " Developing Grid computing applications Part 1 " http //www 106 ibm com/developerworks/webservices/li brary/ws grid1/ [ch02biblio01div03entry06] Liang Jie Zhang Jen Yao Chung and Qun Zhou " Developing Grid computing applications Part 2 " http //www 106 ibm com/developerworks/webservices/li brary/ws grid2/ Other References [ch02biblio01div04entry01] White label service using Web Services i Deal http //www lighthouse partners com/wallstreettng/presentations/Frank%20LaQuinta ppt