AnserModel:
getValueAt(int row, int col) method returns Answer Objects
added removeValueAt(int row) method
ProblemModel:
getValueAt(int, int) method returns Problem Objects
added removeValueAt(int row) method
Modified Files:
src/java/de/fhworms/ztt/ox/examrepository/AnswerModel.java
src/java/de/fhworms/ztt/ox/examrepository/ProblemModel.java
src_test/java/unit/de/fhworms/ztt/ox/examrepository/AnswerModelTest.java
