public Collection<VariableSummary> getVariablesCurrentState(
     long processInstanceId, String processId) {
   Map<String, String> properties =
       new HashMap<String, String>(bpmn2Service.getProcessData(processId));
   return VariableHelper.adaptCollection(
       dataService.getVariablesCurrentState(processInstanceId), properties, processInstanceId);
 }
 @Override
 public Collection<VariableSummary> getVariableHistory(long processInstanceId, String variableId) {
   return VariableHelper.adaptCollection(
       dataService.getVariableHistory(processInstanceId, variableId));
 }