1. B. RAMAMURTHY Developing Applications with SaaS (Software as a Service) 11/4/2015 1

2. References http://www.netbeans.org/kb/docs/websvc/zillow.html Introduction to Web Services - NetBeans IDE 6.1-6.5 11/4/2015 2

3. Web services 11/4/2015 3 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.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.SOAP-based Web Services

4. Software as a Service (SaaS) 11/4/2015 4 “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 11/4/2015 5 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 11/4/2015 6 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.