7.2. Framework Usage / Code Generation

GMT frameworks are intended to be extensible by specializing a set of base classes. A set of tools provides the capability to generate the skeleton of a component implementation from the specification of its interface. The Figure below (Component Skeleton Generation) shows the relation between generated skeletons and the GMT modeling framework.

The skeleton generation tools are available for every layer of the modeling framework, i.e. they can generate the skeleton of a model element from the metamodel or generate the skeleton of a runtime component from the model specification.

Fig. 7.1 Component Skeleton Generation. The GMT modeling framework is based in the OMG Meta Object Facility specification. The group on the left shows the main entities in the layered modeling architecture. A set of modular plugins allows one to generate skeletons and instances from layer to layer. The gen_skeleton function (1) allows the generation of the skeleton of a model element. The gen_instance function (2) allows the capability to generate the skeleton of an instance of a model element. Instances are created in the next model layer and they inherit the behavior of some of the framework base classes.

The table below describes three common framework use cases and the functionality provided by the frameworks involved.

Table 7.3 Framework Typical Use Cases

Use Case	Framework	Base Classes	Function
Create a new Controller	Core Framework	Base Component	Provides access to observatory services
	Device Control Framework	BaseDeviceController	Provides usable control building blocks
	I/O Framework	IOModule, Device	Provides access to the hardware
Create a new Pipeline	Core Framework	BaseComponent	Provides access to the observatory services
	Data Processing Framework	Pipeline, Filter, Recipe	Defines a reference architecture for data processing pipelines
	Persistence Framework	ObjectStore, FileStore	Provides persistence to files and data structures
Create a new Panel	Core Framework	BaseComponent	Provides access to Observatory Services
	UI Framework	Panel, Widget	Provides reusable visualization components