private boolean validOp(String opValue) {
    try {
      UpdateOp.valueOf(opValue.toUpperCase());
      return true;
    } catch (IllegalArgumentException ex) {
      return false;
    }
  }
Update data for a key or set of keys

@param region gemfire data region
@param keys comma seperated list of keys
@param opValue type of update (put, replace, cas etc)
@param json new data for the key(s)
@return JSON document
geode-web-api/src/main/java/org/apache/geode/rest/internal/web/controllers/PdxBasedCrudController.java