Examples with RexVisitorImpl org.apache.calcite.rex.RexVisitorImpl used on opensource projects

Example 11 with RexVisitorImpl

use of org.apache.calcite.rex.RexVisitorImpl in project drill by apache.

the class DrillRelOptUtil method analyzeSimpleEquiJoin.

public static List<Pair<Integer, Integer>> analyzeSimpleEquiJoin(Join join) {
    List<Pair<Integer, Integer>> joinConditions = new ArrayList<>();
    try {
        RexVisitor<Void> visitor = new RexVisitorImpl<Void>(true) {

            @Override
            public Void visitCall(RexCall call) {
                if (call.getKind() == SqlKind.AND || call.getKind() == SqlKind.OR) {
                    super.visitCall(call);
                } else {
                    if (call.getKind() == SqlKind.EQUALS) {
                        RexNode leftComparand = call.operands.get(0);
                        RexNode rightComparand = call.operands.get(1);
                        // we bail out!
                        if (!(leftComparand instanceof RexInputRef && rightComparand instanceof RexInputRef)) {
                            joinConditions.clear();
                            throw new Util.FoundOne(call);
                        }
                        int leftFieldCount = join.getLeft().getRowType().getFieldCount();
                        int rightFieldCount = join.getRight().getRowType().getFieldCount();
                        RexInputRef leftFieldAccess = (RexInputRef) leftComparand;
                        RexInputRef rightFieldAccess = (RexInputRef) rightComparand;
                        if (leftFieldAccess.getIndex() >= leftFieldCount + rightFieldCount || rightFieldAccess.getIndex() >= leftFieldCount + rightFieldCount) {
                            joinConditions.clear();
                            throw new Util.FoundOne(call);
                        }
                        /* Both columns reference same table */
                        if ((leftFieldAccess.getIndex() >= leftFieldCount && rightFieldAccess.getIndex() >= leftFieldCount) || (leftFieldAccess.getIndex() < leftFieldCount && rightFieldAccess.getIndex() < leftFieldCount)) {
                            joinConditions.clear();
                            throw new Util.FoundOne(call);
                        } else {
                            if (leftFieldAccess.getIndex() < leftFieldCount) {
                                joinConditions.add(Pair.of(leftFieldAccess.getIndex(), rightFieldAccess.getIndex() - leftFieldCount));
                            } else {
                                joinConditions.add(Pair.of(rightFieldAccess.getIndex(), leftFieldAccess.getIndex() - leftFieldCount));
                            }
                        }
                    }
                }
                return null;
            }
        };
        join.getCondition().accept(visitor);
    } catch (Util.FoundOne ex) {
        Util.swallow(ex, null);
    }
    return joinConditions;
}