Android的BLE技术中的GattAttributes是干什么的？

最近在研究BLE技术发现了这个东西有一点不明白，有一个GattAttributes的文件

/**

• This class includes a small subset of standard GATT attributes for demonstration purposes.
  */
  public class SampleGattAttributes {
  private static HashMap attributes = new HashMap();
  public static String HEART_RATE_MEASUREMENT = "00002a37-0000-1000-8000-00805f9b34fb";
  public static String CLIENT_CHARACTERISTIC_CONFIG = "00002902-0000-1000-8000-00805f9b34fb";

  static {
  // Sample Services.
  attributes.put("0000180d-0000-1000-8000-00805f9b34fb", "Heart Rate Service");
  attributes.put("0000180a-0000-1000-8000-00805f9b34fb", "Device Information Service");
  // Sample Characteristics.
  attributes.put(HEART_RATE_MEASUREMENT, "Heart Rate Measurement");
  attributes.put("00002a29-0000-1000-8000-00805f9b34fb", "Manufacturer Name String");
  }

  public static String lookup(String uuid, String defaultName) {
  String name = attributes.get(uuid);
  return name == null ? defaultName : name;
  }
  }

翻译说是一种协议，请问用来干嘛的？