code: private boolean getOverwriteOption(Map<String, String> options) {
          boolean bOverwrite = true;
          if (options != null) {
              for (String name : options.keySet()) {
                  if ("overwrite".equals(name.toLowerCase())) {
                      bOverwrite = Boolean.parseBoolean(options.get(name));
                  } else {
                      Utils.require(false, "Unknown OLAP batch option: " + name);
                  }
              }
          }
          return bOverwrite;
      }
docs: Get case-insensitive "overwrite" option. Default to "true".