// The effort of the worker is the sum of all efforts.
EffortDuration effortWorker = EffortDuration.sum(current,
EffortDuration.parseFromFormattedString((String) this
.getVariableValue("sumHoursPerWorker")));
this.setVariableValue("sumHoursPerWorker",
effortWorker.toFormattedString());
// We calculate here the effort for a particular day
EffortDuration effort = EffortDuration.sum(current, EffortDuration
.parseFromFormattedString((String) this
.getVariableValue("sumHoursPerDay")));
this.setVariableValue("sumHoursPerDay", effort.toFormattedString());