content: /*
   * Licensed to the Apache Software Foundation (ASF) under one or more
   * contributor license agreements. See the NOTICE file distributed with
   * this work for additional information regarding copyright ownership.
   * The ASF licenses this file to You under the Apache License, Version 2.0
   * (the "License"); you may not use this file except in compliance with
   * the License. You may obtain a copy of the License at
   *
   *    http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
  package org.apache.kafka.streams;
  
  import org.apache.kafka.common.Metric;
  import org.apache.kafka.common.MetricName;
  import org.apache.kafka.common.metrics.Sensor;
  
  import java.util.Map;
  
  /**
   * The Kafka Streams metrics interface for adding metric sensors and collecting metric values.
   */
  public interface StreamsMetrics {
  
      /**
       * Get read-only handle on global metrics registry.
       *
       * @return Map of all metrics.
       */
      Map<MetricName, ? extends Metric> metrics();
  
      /**
       * Add a latency, rate and total sensor for a specific operation, which will include the following metrics:
       * <ol>
       * <li>average latency</li>
       * <li>max latency</li>
       * <li>invocation rate (num.operations / seconds)</li>
       * <li>total invocation count</li>
       * </ol>
       * Whenever a user records this sensor via {@link Sensor#record(double)} etc., it will be counted as one invocation
       * of the operation, and hence the rate / count metrics will be updated accordingly; and the recorded latency value
       * will be used to update the average / max latency as well.
       *
       * <p>Note that you can add more metrics to this sensor after you created it, which can then be updated upon
       * {@link Sensor#record(double)} calls.
       *
       * <p>The added sensor and its metrics can be removed with {@link #removeSensor(Sensor) removeSensor()}.
       *
       * @param scopeName          name of the scope, which will be used as part of the metric type, e.g.: "stream-[scope]-metrics".
       * @param entityName         name of the entity, which will be used as part of the metric tags, e.g.: "[scope]-id" = "[entity]".
       * @param operationName      name of the operation, which will be used as the name of the metric, e.g.: "[operation]-latency-avg".
       * @param recordingLevel     the recording level (e.g., INFO or DEBUG) for this sensor.
       * @param tags               additional tags of the sensor
       * @return The added sensor.
       * @see #addRateTotalSensor(String, String, String, Sensor.RecordingLevel, String...)
       * @see #removeSensor(Sensor)
       * @see #addSensor(String, Sensor.RecordingLevel, Sensor...)
       */
      Sensor addLatencyRateTotalSensor(final String scopeName,
                                       final String entityName,
                                       final String operationName,
                                       final Sensor.RecordingLevel recordingLevel,
                                       final String... tags);
  
      /**
       * Add a rate and a total sensor for a specific operation, which will include the following metrics:
       * <ol>
       * <li>invocation rate (num.operations / time unit)</li>
       * <li>total invocation count</li>
       * </ol>
       * Whenever a user records this sensor via {@link Sensor#record(double)} etc.,
       * it will be counted as one invocation of the operation, and hence the rate / count metrics will be updated accordingly.
       *
       * <p>Note that you can add more metrics to this sensor after you created it, which can then be updated upon
       * {@link Sensor#record(double)} calls.
       *
       * <p>The added sensor and its metrics can be removed with {@link #removeSensor(Sensor) removeSensor()}.
       *
       * @param scopeName          name of the scope, which will be used as part of the metrics type, e.g.: "stream-[scope]-metrics".
       * @param entityName         name of the entity, which will be used as part of the metric tags, e.g.: "[scope]-id" = "[entity]".
       * @param operationName      name of the operation, which will be used as the name of the metric, e.g.: "[operation]-total".
       * @param recordingLevel     the recording level (e.g., INFO or DEBUG) for this sensor.
       * @param tags               additional tags of the sensor
       * @return The added sensor.
       * @see #addLatencyRateTotalSensor(String, String, String, Sensor.RecordingLevel, String...)
       * @see #removeSensor(Sensor)
       * @see #addSensor(String, Sensor.RecordingLevel, Sensor...)
       */
      Sensor addRateTotalSensor(final String scopeName,
                                final String entityName,
                                final String operationName,
                                final Sensor.RecordingLevel recordingLevel,
                                final String... tags);
  
      /**
       * Generic method to create a sensor.
       * Note that for most cases it is advisable to use
       * {@link #addRateTotalSensor(String, String, String, Sensor.RecordingLevel, String...) addRateTotalSensor()}
       * or {@link #addLatencyRateTotalSensor(String, String, String, Sensor.RecordingLevel, String...) addLatencyRateTotalSensor()}
       * to ensure metric name well-formedness and conformity with the rest of the Kafka Streams code base.
       * However, if the above two methods are not sufficient, this method can also be used.
       *
       * @param name           name of the sensor.
       * @param recordingLevel the recording level (e.g., INFO or DEBUG) for this sensor
       * @return The added sensor.
       * @see #addRateTotalSensor(String, String, String, Sensor.RecordingLevel, String...)
       * @see #addLatencyRateTotalSensor(String, String, String, Sensor.RecordingLevel, String...)
       * @see #removeSensor(Sensor)
       */
      Sensor addSensor(final String name,
                       final Sensor.RecordingLevel recordingLevel);
  
      /**
       * Generic method to create a sensor with parent sensors.
       * Note that for most cases it is advisable to use
       * {@link #addRateTotalSensor(String, String, String, Sensor.RecordingLevel, String...) addRateTotalSensor()}
       * or {@link #addLatencyRateTotalSensor(String, String, String, Sensor.RecordingLevel, String...) addLatencyRateTotalSensor()}
       * to ensure metric name well-formedness and conformity with the rest of the Kafka Streams code base.
       * However, if the above two methods are not sufficient, this method can also be used.
       *
       * @param name           name of the sensor
       * @param recordingLevel the recording level (e.g., INFO or DEBUG) for this sensor
       * @return The added sensor.
       * @see #addRateTotalSensor(String, String, String, Sensor.RecordingLevel, String...)
       * @see #addLatencyRateTotalSensor(String, String, String, Sensor.RecordingLevel, String...)
       * @see #removeSensor(Sensor)
       */
      Sensor addSensor(final String name,
                       final Sensor.RecordingLevel recordingLevel,
                       final Sensor... parents);
  
      /**
       * Remove a sensor.
       * @param sensor sensor to be removed
       */
      void removeSensor(final Sensor sensor);
  }
  