code: public BoltDeclarer setBolt(String id, ITridentBatchBolt bolt, Integer parallelism, Set<String> committerBatches, Map<String, String> batchGroups) {
          markBatchGroups(id, batchGroups);
          Component c = new Component(bolt, parallelism, committerBatches);
          _bolts.put(id, c);
          return new BoltDeclarerImpl(c);
          
      }
docs: map from stream name to batch id