IPartitioner partitioner = null;
Range<Token> jobRange = null;
if (jobKeyRange != null && jobKeyRange.start_token != null)
{
partitioner = ConfigHelper.getInputPartitioner(context.getConfiguration());
assert partitioner.preservesOrder() : "ConfigHelper.setInputKeyRange(..) can only be used with a order preserving paritioner";
assert jobKeyRange.start_key == null : "only start_token supported";
assert jobKeyRange.end_key == null : "only end_token supported";
jobRange = new Range<Token>(partitioner.getTokenFactory().fromString(jobKeyRange.start_token),
partitioner.getTokenFactory().fromString(jobKeyRange.end_token),
partitioner);