Flash® Builder™ 4 and Flex® 4 Bible

Chapter 18. Modeling and Managing Data

IN THIS CHAPTER

• Using the <fx:Model> tag to model data items

• Embedding data with <fx:Model>

• Creating value object classes in ActionScript

• Storing data sets in client memory with the ArrayList and ArrayCollection classes

• Filtering and sorting data with the ArrayCollection class

• Traversing, searching, and bookmarking data objects with the IViewCursor interface

Flex applications are stateful; that is, they have the capability to remember data persistently for the duration of the user's session in a way that classic Web applications usually don't. One of the most common tasks you must accomplish as an application developer is to create a framework for storing data that the application can use at runtime.

The content of an application's data can come from many sources: XML files, databases or other server-side resources, or remote functions wrapped by and exposed as SOAP-style or Representational State Transfer (REST)-style Web services. Regardless of how the data comes to an application, though, a Flex application stores the data in exactly the same way: as a data model.

In this chapter, I describe common techniques for modeling data in Flex applications. I start with creating single-object data models: ActionScript classes designed to hold one instance of a data entity at a time. (A data instance might represent a row in a database table or a single element in an XML file.) You can represent such data instances with the <fx:Model> tag, a generic data object, ...