public void init(NimbusData nimbusData) {
this.nimbusData = nimbusData;
this.schedulers = new HashMap<String, IToplogyScheduler>();
IToplogyScheduler defaultScheduler = new DefaultTopologyScheduler();
defaultScheduler.prepare(nimbusData.getConf());
schedulers.put(DEFAULT_SCHEDULER_NAME, defaultScheduler);
thread = new Thread(this);
thread.setName("TopologyAssign");