content: package act.metric;
  
  /*-
   * #%L
   * ACT Framework
   * %%
   * Copyright (C) 2014 - 2017 ActFramework
   * %%
   * Licensed 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.
   * #L%
   */
  
  import java.util.List;
  
  /**
   * {@code MetricStore} back all {@link Metric} instances generated
   * in ActFramework.
   */
  public interface MetricStore {
  
      /**
       * Increment one on counter specified
       * @param name A string specify the counter
       */
      void countOnce(String name);
  
      void onTimerStart(String name);
  
      void onTimerStop(Timer timer);
  
      /**
       * Returns the counts of counter specified
       *
       * @param name A string specifies the counter
       * @return the counts or {@code null} if the counter cannot be found
       */
      Long count(String name);
  
      /**
       * Returns the aggregated time in nanoseconds of timer specified
       *
       * @param name A string specifies the timer
       * @return the aggregated time in nanoseconds or {@code null} if counter cannot be found
       */
      Long ns(String name);
  
      /**
       * Returns all counter names
       * @return counter names in a list
       */
      List<MetricInfo> counters();
  
      /**
       * Returns all timer names
       * @return timer names in a list
       */
      List<MetricInfo> timers();
  
      /**
       * Clear metric data
       */
      void clear();
  }
  