code: public BoltDeclarer setBolt(String id, IRichBolt bolt, Number parallelismHint) {
      validateComponentName(id);
      BoltDeclarer b = new BoltDeclarer(id, bolt, parallelismHint);
      bolts.put(id, b);
      return b;
    }
docs: Define a new bolt in this topology with the specified amount of parallelism.
  
  @param id the id of this component. This id is referenced by other components that want to consume this bolt's outputs.
  @param bolt the bolt
  @param parallelismHint the number of tasks that should be assigned to execute this bolt. Each task will run on a thread in a process somewhere around the cluster.
  @return use the returned object to declare the inputs to this component