IObservableList observableBeanList = new WritableList(studentList, Student.class); IObservableSet observableBeanSet = new ListToSetAdapter( observableBeanList); IObservableMap map = AggregateProperties.average( EMFProperties.list(ClassroomPackage.Literals.STUDENT__TEST_RESULTS) .values(ClassroomPackage.Literals.EXAM_RESULT__SCORE)) .observeDetail(observableBeanSet);
Saturday, September 25, 2010
In RCP apps I'm working on, especially when displaying numeric data in a Table, I often find myself wanting to have some aggregation support built into Eclipse's databinding framework. As an example, if I have a list of Students, and each Student has a list of ExamResults, it would be nice to easily bind a TableColumn to the average of each student's exam results. To that end, I've created a new project, net.juckel.rcp.databinding.aggregate. I'm relatively new to extending the databinding framework, so I'd greatly appreciate comments on the the API design, as well as suggestions for how to extend the functionality. As a quick example (pulled from the tests on github), here's how you'd create an observable map for the example given above (average score for each student in a list).