// 6. Translate Window spec
RowResolver inputRR = relToHiveRR.get(srcRel);
WindowSpec wndSpec = ((WindowFunctionSpec) wExpSpec).getWindowSpec();
List<RexNode> partitionKeys = getPartitionKeys(wndSpec.getPartition(), converter, inputRR);
List<RexFieldCollation> orderKeys = getOrderKeys(wndSpec.getOrder(), converter, inputRR);
RexWindowBound upperBound = getBound(wndSpec.windowFrame.start, converter);
RexWindowBound lowerBound = getBound(wndSpec.windowFrame.end, converter);
boolean isRows = ((wndSpec.windowFrame.start instanceof RangeBoundarySpec) || (wndSpec.windowFrame.end instanceof RangeBoundarySpec)) ? true
: false;
w = cluster.getRexBuilder().makeOver(optiqAggFnRetType, optiqAggFn, optiqAggFnArgs,
partitionKeys, ImmutableList.<RexFieldCollation> copyOf(orderKeys), lowerBound,