Bug 324587

Description Martin Taal 2010-09-06 10:25:20 EDT

Applications often need to visualize an object in the user interface. In reports, comboboxes, grids etc. A way of doing is to introduce the title concept for an object, so each object has a title which is used to display that object in a combobox or in a grid. 

The title is defined on type level by either flagging the efeatures which make up the title or by providing an expression on type level which references the efeatures.

Implementation decisions:
- what expression language should be used for the title definition, performance is important here
- how to model the title at runtime: in the model as annotations or using java annotations? The first is flexible but can be more complex, the second introduces compile time dependencies on Texo and means that reflexion needs to be used which implies a performance hit. Another choice can be to generate code which for specific types takes care of returning the title (and id). The disadvantage is that title spec changes always require a re-generation, on the other hand, titles/ids don't change that often.

The same solution as for the title also needs to be provided for the Id, so we should be able to retrieve the id of an object based on information provided in the class/eclass of that object. We can make use of the JPA @Id annotation but this functionality also needs to be provided for non-jpa cases.