title: Optaplanner Drools rules error
body: <p>I have the following Drools rule in Optaplanner:</p>
  
  <pre><code>rule "oneShiftPerDay"
  when
      $leftAssignment : ShiftAssignment($leftId : id, $employee : employee, $shiftDate : shiftDate, employee != null)
      $rightAssignment : ShiftAssignment(employee == $employee, shiftDate == $shiftDate, id &gt; $leftId)
  then
      scoreHolder.addHardConstraintMatch(kcontext, -1); end
  </code></pre>
  
  <p>But when I run the solver I get the following error:</p>
  
  <pre><code>09:02:46.128 [main] ERROR o.d.c.k.b.impl.AbstractKieModule - Unable to build     KieBaseModel:defaultKieBase Error                      importing : 'be.comp.permanenties.domain.solver.EmployeeAssignmentTotal'
  Error importing : 'be.comp.permanenties.domain.solver.EmployeeWorkSequence'
  Rule Compilation error : [Rule name='oneShiftPerDay']
          be/comp/permanenties/solver/Rule_oneShiftPerDay544009415.java (2:220) : Only a type can be imported. be.comp.permanenties.domain.solver.EmployeeWorkSequence resolves to a package
          be/comp/permanenties/solver/Rule_oneShiftPerDay544009415.java (2:978) : Only a type can be imported. be.comp.permanenties.domain.solver.EmployeeAssignmentTotal resolves to a package
  </code></pre>
  
  <p>How can I solve this error? Thanks.</p>
  
  <p>Kind regards,</p>
  
  <p>Nick</p>