Application Class

The Application class provides a superclass for all user application classes. Each user application is defined as an instance of the Application class. The Application class defines standard properties and methods for the running of any application.

Each time you create a new schema, an instance of the Application class is created for that schema. When you load a schema from a file and there is application data (in the .ddb or .ddx form and data definition file), JADE creates an instance of the Application class for each application defined in this file.

Each schema also has a subclass of the Application class. A transient instance of this class is automatically made available to the runtime copy of the application. To access this transient instance, use the app system variable in your method logic; for example, use app.name to access the name of the application. This transient instance is unique to a specific copy of the application. Changes made to the properties are retained until the application copy is terminated. (This data is therefore not available to other copies of the application.)

Transient objects that are automatically created by JADE cannot be shared, including the application object and exclusive collections. (For details about specifying the creation of transient objects that can be shared across threads, see "create Instruction", in Chapter 1 of the JADE Developer’s Reference.)

Unpredictable results may occur when several processes concurrently access and modify transient objects that are not shared.

You can remove user-defined applications from a schema, providing that at least one application remains in the schema.

For details about the constants, properties, and methods defined in the Application class, see "Application Class Constants", "Application Properties", and "Application Methods", in the following subsections.

Object

RootSchemaApp, user-defined Application classes