The UI Engine can be extended to support new kinds of ULC objects like widgets and data types (that is, type converters and formatters). This section demonstrates the required steps for implementing a ULC widget. As discussed in Overview of ULC, a ULC widget consists of two half objects:
In addition to the half objects, there is the real widget, which often
already exists and needs to be adapted to be used in ULC. The
development of a ULC extension is demonstrated based on the PieChart widget,
which is shown in the following illustration:
Implementing a new ULC widget requires the following steps:
The real widget and the UI half must be implemented in Java. The faceless half can be implemented in either Java and Smalltalk, depending on the needs of your business.