B. Ramamurthy

1
Developing Applications with SaaS (Software as a
Service)

• B. Ramamurthy

2
References

• http//www.netbeans.org/kb/docs/websvc/zillow.html
  
• Introduction to Web Services - NetBeans IDE
  6.1-6.5

3
Web services

• Web services are components that expose a
  software module for use by distributed
  applications.
• The operations offered by a service are usually
  exposed using one or more interfaces.
• There are two popular programming models
  available for interacting with the web services
  (WS)
• REST-based. REpresentational State Transfer is a
  new way to create and communicate with web
  services. In REST, resources have URIs and are
  manipulated through HTTP header operations. For
  more details, see RESTful Web Services.
• SOAP/WSDL-based. In traditional web service
  models, web service interfaces are exposed
  through WSDL documents (a type of XML), which
  have URLs. Subsequent message exchange is in
  SOAP, another type of XML document. For more
  details, see SOAP-based Web Services.

4
Software as a Service (SaaS)

• SaaS refers to a software application delivery
  model where a software vendor develops a
  web-native software application and hosts and
  operates the application for use by its customers
  over the Internet. SaaS is an increasingly
  popular model for providing software
  functionality as it is economical in terms of
  both cost and customer hardware resources. ref
  1 on slide 2
• You can be a consumer of SaaS or provider/vendor
  of SaaS.
• For example, providing a nutritional counseling
  SaaS.
• Consuming the SaaS provided Zillow.
• We will work on developing an application that
  consumes SaaS offered by Zillow.
• Zillow.com is a Seattle, Washington-based online
  real estate service company founded in 2005 by
  Rich Barton and Lloyd Frink, former Microsoft
  executives and founders of Expedia.

5
Steps in SaaS Application Development

• Choose the SaaS you want to work with.
• Register yourself with the vendor sometimes it
  is free and other times you may have to pay for
  using the SaaS (eg. Amazon ECS and S3)
• Decide on the model for interaction REST or
  SOAP. This is not a big deal if you are using an
  IDE since IDE like Netbeans hides the details of
  this model and provides a uniform view.
• Create a web application that will consume the
  SaaS.
• Create a servlet or JSP to insert the web service
  request.
• Drag and drop the web service request, make sure
  you initialize the input parameters to the WS.
• Build a front-end (JSP) so that application can
  be tested with user defined parameters.
• Build a persistent model for storing any data
  that may be generated (this is the database
  component we will look at this in a future
  presentation.)

6
Zillow Application

• Registering To Receive the Zillow API Key
• Creating the Servlet
• Adding the Zillow GetRegionChart Operation to the
  Servlet
• Adding the API Key to the Project
• Modifying the Servlet to Return the Chart Graphic
  
• Running the Zillow Region Chart Servlet
• We will add a JSP as user interface to the above
  application so that we can run the application
  for any user input.