UI DSL
Purpose
The UI DSL facilitates the creation of model-based user interfaces (UIs) and their integration into complex applications. It is not intended for styling and design specifications.
Using UI DSL, layouts and fields can easily be defined along with the appropriate validation and binding mechanisms. The underlying ECView model uses Eclipse databinding to create an efficient databinding between UI elements and the Java objects they represent. The UI model is kept independent of rendering implementations so that it can be easily re-used.
By referencing DTO models (as defined by the DTO DSL) in the UI DSL, UI model and internal application logic can be tightly interwoven. The ECView UI model is extensible and allows for a straightforward implementation of new UI elements.
The UI DSL is used to define UI models along with the desired validators and databindings. Valid UI DSL files are compiled to ECView model definitions (Java classes) that are interpreted by the UI renderer in real time. Thus, the UI DSL acts as a simplified frontend for the ECView model.
In the reference implementation, Vaadin has been chosen as the UI framework that is used to render the UI model. However, since the model-view-controller distinction has been observed, it is possible to change the rendering service without having to change the underlying UI model. For example, JavaFX might be used to render the exact same UI model as Vaadin.
ECView is a UI model based on the Eclipse Modeling Framework (EMF). It defines various UI elements and their properties and possible relations. UI elements are thus represented as EObjects and can be manipulated accordingly. Furthermore, databinding can be done efficiently by using the Eclipse databinding mechanism. ECView attaches so-called editparts to its model elements. Acting as controllers, these editparts tie the application's model and its visual representation together. Editparts are responsible for making changes to the model. ECView provides support for various validation mechanisms (min-length, max-length, regex ...). The `UI DSL can make use of such validations easily and allows the definition of additional custom validators using Xexpressions. Application logic can interface with the UI model using the editparts of the respective model elements (reading values, changing visibility etc.). Furthermore, the rendered UI may be addressed by application logic directly, if necessary.
