/// <summary>
/// Evaluates the LeftJoin
/// </summary>
/// <param name="context">Evaluation Context</param>
/// <returns></returns>
public BaseMultiset Evaluate(SparqlEvaluationContext context)
{
// Need to be careful about whether we linearize (CORE-406)
if (!CanLinearizeLhs(context))
{
context.InputMultiset = new IdentityMultiset();
}
BaseMultiset lhsResult = context.Evaluate(_lhs);
context.CheckTimeout();
if (lhsResult is NullMultiset)
{
context.OutputMultiset = lhsResult;
}
else if (lhsResult.IsEmpty)
{
context.OutputMultiset = new NullMultiset();
}
else
{
// Only execute the RHS if the LHS had some results
// Need to be careful about whether we linearize (CORE-406)
context.InputMultiset = CanFlowResultsToRhs(context) && !IsCrossProduct ? lhsResult : new IdentityMultiset();
BaseMultiset rhsResult = context.Evaluate(_rhs);
context.CheckTimeout();
context.OutputMultiset = lhsResult.LeftJoin(rhsResult, _filter.Expression);
context.CheckTimeout();
}
context.InputMultiset = context.OutputMultiset;
return(context.OutputMultiset);
}
/// <summary>
/// Evaluates the LeftJoin
/// </summary>
/// <param name="context">Evaluation Context</param>
/// <returns></returns>
public BaseMultiset Evaluate(SparqlEvaluationContext context)
{
BaseMultiset initialInput = context.InputMultiset;
BaseMultiset lhsResult = context.Evaluate(this._lhs);//this._lhs.Evaluate(context);
context.CheckTimeout();
if (lhsResult is NullMultiset)
{
context.OutputMultiset = lhsResult;
}
else if (lhsResult.IsEmpty)
{
context.OutputMultiset = new NullMultiset();
}
else
{
//Only execute the RHS if the LHS had some results
context.InputMultiset = lhsResult;
BaseMultiset rhsResult = context.Evaluate(this._rhs);
context.CheckTimeout();
context.OutputMultiset = lhsResult.LeftJoin(rhsResult, this._filter.Expression);
context.CheckTimeout();
}
context.InputMultiset = context.OutputMultiset;
return(context.OutputMultiset);
}