public int getNumRegionsOpened() {
    // TODO: Used by TestRegionPlacement.java and assume monotonically increasing value
    return 0;
  }
Used to check if the meta loading is done.
<p/>
if not we throw PleaseHoldException since we are rebuilding the RegionStates
@param hri region to check if it is already rebuild
@throws PleaseHoldException if meta has not been loaded yet
hbase-server/src/main/java/org/apache/hadoop/hbase/master/assignment/AssignmentManager.java