25.11. Equation Generator: Returning User-Defined Types

With the exception of the WelcomeRESTJSONService (Fig. 25.15), the web services we’ve demonstrated all received and returned primitive-type instances. It is also possible to process instances of complete user-defined types in a web service. These types can be passed to or returned from web-service methods.

This section presents an EquationGenerator web service that generates random arithmetic equations of type Equation. The client is a math-tutoring application that inputs information about the mathematical question that the user wishes to attempt (addition, subtraction or multiplication) and the skill level of the user (1 specifies equations using numbers from 1 to 10, 2 specifies equations involving numbers from 10 to 100, and 3 specifies equations containing numbers from 100 to 1000). The web service then generates an equation consisting of random numbers in the proper range. The client application receives the Equation and displays the sample question to the user.