public interface Rate extends IMetric {
  /**
   * Get value of Rate
   * @return
   */
  long getCount();

  /**
   * Get one minute rate
   * @return
   */
  double getOneMinuteRate();

  /**
   * Get mean rate
   * @return
   */
  double getMeanRate();

  /**
   * Get five minute rate
   * @return
   */
  double getFiveMinuteRate();

  /**
   * Get fifteen minute rate
   * @return
   */
  double getFifteenMinuteRate();

  /**
   * mark in rate
   */
  void mark();

  /**
   * mark n in rate
   * @param n
   */
  void mark(long n);
}

public interface Histogram extends IMetric {
  /**
   * update histogram by value
   * @param value
   */
  void update(int value);

  /**
   * update histogram by value
   * @param value
   */
  void update(long value);

  /**
   * get value of histogram
   * @return
   */
  long count();

  /**
   * tak snapshot of histogram
   * @return
   */
  HistogramSnapshot takeSnapshot();
}




public interface HistogramSnapshot {

  /**
   * Get value by quantile
   * @param quantile
   * @return
   */
  public abstract double getValue(double quantile);

  /**
   * Get values in snapshot
   * @return
   */
  public abstract long[] getValues();

  /**
   * Get size of value in snapshot
   * @return
   */
  public abstract int size();

  /**
   * Get median of values
   * @return
   */
  public double getMedian();

  /**
   * Get min of values
   * @return
   */
  public abstract long getMin();

  /**
   * Get mean of values
   * @return
   */
  public abstract double getMean();

  /**
   * Get max of values
   * @return
   */
  public abstract long getMax();

  /**
   * Writes the values of the snapshot to the given stream.
   *
   * @param output an output stream
   */
  public abstract void dump(OutputStream output);
}

public interface Timer extends IMetric {

  /**
   * update time of timer
   * @param duration
   * @param unit
   */
  void update(long duration, TimeUnit unit);

  /**
   * update timer by millisecond
   * @param durationMillis
   */
  default void updateMillis(long durationMillis) {
    update(durationMillis, TimeUnit.MILLISECONDS);
  }

  /**
   * update timer by microseconds
   * @param durationMicros
   */
  default void updateMicros(long durationMicros) {
    update(durationMicros, TimeUnit.MICROSECONDS);
  }

  /**
   * update timer by nanoseconds
   * @param durationNanos
   */
  default void updateNanos(long durationNanos) {
    update(durationNanos, TimeUnit.NANOSECONDS);
  }

  /**
   * take snapshot of timer
   * @return
   */
  HistogramSnapshot takeSnapshot();

  /**
   * It's not safe to use the update interface.
   *
   * @return the getOrCreatRate related with the getOrCreateTimer
   */
  Rate getImmutableRate();
}

public interface MetricManager {
  /**
   * Get Counter
   * If exists, then return
   * or create one to return
   * @param metric
   * @param tags string appear in pairs, like sg="ln" will be "sg", "ln"
   * @return
   */
  Counter getOrCreateCounter(String metric, String... tags);

  /**
   * Get Guage
   * If exists, then return
   * or create one to return
   * @param metric
   * @param tags string appear in pairs, like sg="ln" will be "sg", "ln"
   * @return
   */
  Gauge getOrCreatGauge(String metric, String... tags);

  /**
   * Get Rate
   * If exists, then return
   * or create one to return
   * @param metric
   * @param tags string appear in pairs, like sg="ln" will be "sg", "ln"
   * @return
   */
  Rate getOrCreatRate(String metric, String... tags);

  /**
   * Get Histogram
   * If exists, then return
   * or create one to return
   * @param metric
   * @param tags string appear in pairs, like sg="ln" will be "sg", "ln"
   * @return
   */
  Histogram getOrCreateHistogram(String metric, String... tags);

  /**
   * Get Timer
   * If exists, then return
   * or create one to return
   * @param metric
   * @param tags string appear in pairs, like sg="ln" will be "sg", "ln"
   * @return
   */
  Timer getOrCreateTimer(String metric, String... tags);

  /**
   * Update Counter
   * @param delta
   * @param metric
   * @param tags
   */
  void count(int delta, String metric, String... tags);

  /**
   * Update Counter
   * @param delta
   * @param metric
   * @param tags
   */
  void count(long delta, String metric, String... tags);

  /**
   * update Gauge
   * @param value
   * @param metric
   * @param tags
   */
  void gauge(int value, String metric, String... tags);

  /**
   * update Gauge
   * @param value
   * @param metric
   * @param tags
   */
  void gauge(long value, String metric, String... tags);

  /**
   * update Rate
   * @param value
   * @param metric
   * @param tags
   */
  void rate(int value, String metric, String... tags);

  /**
   * update Rate
   * @param value
   * @param metric
   * @param tags
   */
  void rate(long value, String metric, String... tags);

  /**
   * update Histogram
   * @param value
   * @param metric
   * @param tags
   */
  void histogram(int value, String metric, String... tags);

  /**
   * update Histogram
   * @param value
   * @param metric
   * @param tags
   */
  void histogram(long value, String metric, String... tags);

  /**
   * update Timer
   * @param delta
   * @param timeUnit
   * @param metric
   * @param tags
   */
  void timer(long delta, TimeUnit timeUnit, String metric, String... tags);

  /**
   * remove counter
   * @param metric
   * @param tags
   */
  void removeCounter(String metric, String... tags);

  /**
   * remove gauge
   * @param metric
   * @param tags
   */
  void removeGauge(String metric, String... tags);

  /**
   * remove rate
   * @param metric
   * @param tags
   */
  void removeRate(String metric, String... tags);

  /**
   * remove histogram
   * @param metric
   * @param tags
   */
  void removeHistogram(String metric, String... tags);

  /**
   * update timer
   * @param metric
   * @param tags
   */
  void removeTimer(String metric, String... tags);

  /**
   * get all metric keys.
   *
   * @return all MetricKeys, key is metric name, value is tags, which is a string array.
   */
  List<String[]> getAllMetricKeys();

  /**
   * Get all counters
   * @return [name, tags...] -> counter
   */
  Map<String[], Counter> getAllCounters();

  /**
   * Get all gauges
   * @return [name, tags...] -> gauge
   */
  Map<String[], Gauge> getAllGauges();

  /**
   * Get all rates
   * @return [name, tags...] -> rate
   */
  Map<String[], Rate> getAllRates();

  /**
   * Get all histogram
   * @return [name, tags...] -> histogram
   */
  Map<String[], Histogram> getAllHistograms();

  /**
   * Get all timers
   * @return [name, tags...] -> timer
   */
  Map<String[], Timer> getAllTimers();

  /**
   * whether is enable monitor
   * @return
   */
  boolean isEnable();

  /**
   * enable pre-defined metric set.
   *
   * @param metric which metric set we want to collect
   */
  void enablePredefinedMetric(PredefinedMetric metric);

  /**
   * init something.
   *
   * @return whether success
   */
  boolean init();

  /**
   * stop everything and clear
   *
   * @return
   */
  boolean stop();

  /**
   * Get name of manager
   * @return
   */
  String getName();
}

public interface CompositeReporter {

  /**
   * Start all reporter
   * @return
   */
  boolean start();

  /**
   * Start reporter by name
   * name values in jmx, prometheus, iotdb, internal
   * @param reporter
   * @return
   */
  boolean start(String reporter);

  /**
   * Stop all reporter
   * @return
   */
  boolean stop();

  /**
   * Stop reporter by name
   * name values in jmx, prometheus, iotdb, internal
   * @param reporter
   * @return
   */
  boolean stop(String reporter);

  /**
   * set manager to reporter
   * @param metricManager
   */
  void setMetricManager(MetricManager metricManager);

  /**
   * Get name of CompositeReporter
   * @return
   */
  String getName();

public interface MetricReporter {
  boolean start();

  boolean start(String reporter);

  boolean stop();

  boolean stop(String reporter);

  String getName();
}