public ReadWriteLock getLock(LockArea lockArea) {
    return m_locks.get(lockArea);
  }
Gets a lock for the specified lock area. There is a 1:1 relationship
between a lock area and a lock.
<p/>
If the {@link LockArea} is not enabled, then this will return an empty
{@link Lock} implementation which doesn't actually lock anything.

@param lockArea
         the lock area to get the lock for (not {@code null}).
@return the lock to use for the specified lock area (never {@code null}).
ambari-server/src/main/java/org/apache/ambari/server/orm/TransactionalLocks.java