@Override
  public String toString() {
    String ret = "responseId=" + responseId + "\n" +
             "timestamp=" + timestamp + "\n" +
             "startTime=" + agentStartTime + "\n" +
             "hostname="  + hostname + "\n" +
             "currentPingPort=" + currentPingPort + "\n" +
             "prefix=" + prefix + "\n";

    if (hardwareProfile != null)
      ret = ret + "hardwareprofile=" + this.hardwareProfile;
    return ret;
  }
Data model for Ambari Agent to send heartbeat to Ambari Controller.
ambari-server/src/main/java/org/apache/ambari/server/agent/Register.java