C H A P T E R 1 |
Component Overview |
The components in the Web Application Framework Component Library fall into four basic groups: Visual Components, Model Components, Command Components, and Non-Visual Components. See the following sections for more information.
The IDE supports the use of both extensible and non-extensible visual components.
Extensible components are components that can be subclassed. Subclassing of extensible components is transparently facilitated by the IDE. The Web Application Framework IDE wizards automatically create an application-specific class which extends the component base class.
Non-extensible components, visual and non-visual alike, are components that are not normally subclassed in the course of Web Application Framework IDE usage. When a new non-extensible visual component is selected from the component palette, a named instance is created rather than a new subtype.
Visual components are components that developers use to assemble a user interface for an application.
Model components are components that act as a business delegate or a data proxy to an arbitrary data store (Java class, CORBA object, EJB, database, mainframe, ERP system, transaction processor, etc.).
Command components encapsulate arbitrary behavior. Typically, command components encapsulate request handling logic or controller functionality. Command fields (buttons, HREFs) are the primary consumers of command components.
A command that links together two or more command components to be invoked in sequence |
Dependent = Dependent property (for example, a property that is dependent on the value of another property)
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