public PartitionId getRandomFullyWritablePartition(String partitionClass, List<PartitionId> toExclude) {
    return partitionSelectionHelper.getRandomFullyWritablePartition(partitionClass, toExclude);
  }
Constructor for initial PartitionLayout
@param hardwareLayout the {@link JSONObject} that represents the partition layout
@param clusterMapConfig the {@link ClusterMapConfig} to use.
ambry-clustermap/src/main/java/com/github/ambry/clustermap/PartitionLayout.java