/**
  * Converts the given VariableSlot into an annotation using the given AnnotationBuiklder
  *
  * @param variable VariableSlot to convert
  * @param annotationBuilder appropriate annotation for the actual class of the VariableSlot which
  *     could be subtype of VariableSlot. Eg. CombVariableSlots use combVarBuilder which is
  *     parameterized to build @CombVarAnnots
  * @return An annotation representing variable
  */
 private AnnotationMirror convertVariable(
     final VariableSlot variable, final AnnotationBuilder annotationBuilder) {
   annotationBuilder.setValue("value", variable.getId());
   return annotationBuilder.build();
 }
 /** @inheritDoc */
 @Override
 public void addVariable(final VariableSlot slot) {
   variables.put(slot.getId(), slot);
 }