@Override
public boolean rewritePost(Mutable<ILogicalOperator> opRef, IOptimizationContext context)
throws AlgebricksException {
ILogicalOperator lo = opRef.getValue();
if (!(lo.getOperatorTag().equals(LogicalOperatorTag.UNNEST))) {
return false;
}
AbstractUnnestOperator auo = (AbstractUnnestOperator) lo;
Mutable<ILogicalExpression> childExpression =
ExpressionToolbox.findFirstFunctionExpression(
auo.getExpressionRef(), BuiltinOperators.CHILD.getFunctionIdentifier());
if (childExpression == null) {
return false;
}
AbstractFunctionCallExpression childFnCall =
(AbstractFunctionCallExpression) childExpression.getValue();
List<Mutable<ILogicalExpression>> list =
(List<Mutable<ILogicalExpression>>) childFnCall.getArguments();
Mutable<ILogicalExpression> mle = (Mutable<ILogicalExpression>) (list).get(0);
ILogicalExpression le = mle.getValue();
if (!(le.getExpressionTag().equals(LogicalExpressionTag.VARIABLE))) {
return false;
}
VariableReferenceExpression varLogicalExpression = (VariableReferenceExpression) le;
Mutable<ILogicalOperator> lop =
OperatorToolbox.findProducerOf(opRef, varLogicalExpression.getVariableReference());
ILogicalOperator lop1 = lop.getValue();
if (!(lop1.getOperatorTag().equals(LogicalOperatorTag.UNNEST))) {
return false;
}
if (OperatorToolbox.getExpressionOf(lop, varLogicalExpression.getVariableReference()) == null) {
return false;
}
ILogicalExpression variableLogicalExpression =
(ILogicalExpression)
OperatorToolbox.getExpressionOf(lop, varLogicalExpression.getVariableReference())
.getValue();
if (!(variableLogicalExpression
.getExpressionTag()
.equals(LogicalExpressionTag.FUNCTION_CALL))) {
return false;
}
AbstractFunctionCallExpression afce =
(AbstractFunctionCallExpression) variableLogicalExpression;
if (!(afce.getFunctionIdentifier()
.equals(BuiltinOperators.DESCENDANT_OR_SELF.getFunctionIdentifier()))) {
return false;
}
// All conditions have been met.
childFnCall.setFunctionInfo(BuiltinOperators.DESCENDANT_OR_SELF);
childFnCall.getArguments().get(0).setValue(afce.getArguments().get(0).getValue());
ILogicalOperator lo1 = opRef.getValue();
Mutable<ILogicalOperator> mlistOfLo = lo1.getInputs().get(0).getValue().getInputs().get(0);
ILogicalOperator ilo = (ILogicalOperator) mlistOfLo.getValue();
lo.getInputs().get(0).setValue((ILogicalOperator) ilo);
return true;
}
@Override
public String visitVariableReferenceExpression(VariableReferenceExpression expr, Integer indent)
throws AlgebricksException {
return expr.toString();
}