docs: public void setCandidateProperties(GlobalProperties gProps, LocalProperties lProps, Channel initialInput) {
  		if (this.cachedPlans != null) {
  			throw new IllegalStateException();
  		} else {
  			this.cachedPlans = Collections.<PlanNode>singletonList(new BulkPartialSolutionPlanNode(this,
  					"PartialSolution ("+this.getOperator().getName()+")", gProps, lProps, initialInput));
  		}
  	}