@Override
    public int compare(Constraint c1, Constraint c2) {
      // compare the priorities of the constraints stored in their configuration
      return Long.compare(c1.getConf().getLong(PRIORITY_KEY, DEFAULT_PRIORITY),
        c2.getConf().getLong(PRIORITY_KEY, DEFAULT_PRIORITY));
    }
Get the constraints stored in the table descriptor
@param desc        To read from
@param classloader To use when loading classes. If a special classloader is used on a region,
                   for instance, then that should be the classloader used to load the
                   constraints. This could also apply to unit-testing situation, where want to
                   ensure that class is reloaded or not.
@return List of configured {@link Constraint Constraints}
@throws IOException if any part of reading/arguments fails
hbase-server/src/main/java/org/apache/hadoop/hbase/constraint/Constraints.java