public RegionInfo getOne(String regionName) {
		RegionInfo regionInfo = getAll().get(regionName);
		if (regionInfo != null) {
			return regionInfo;
		}
		throw new NGrinderRuntimeException(regionName + " is not exist");
	}
Get region by region name

@param regionName region name
@return region info
ngrinder-controller/src/main/java/org/ngrinder/region/service/RegionService.java