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%
   */
  
  /**
   * Implement a do-nothing {@link Metric}
   */
  enum NullMetric implements Metric {
      INSTANCE
      ;
  
      private static final Timer NULL_TIMER = new Timer() {
          @Override
          public String name() {
              return null;
          }
  
          @Override
          public void stop() {
          }
  
          @Override
          public long ns() {
              return 0;
          }
  
          @Override
          public void close() {
              stop();
          }
      };
  
      @Override
      public void countOnce(String name) {
      }
  
      @Override
      public Timer startTimer(String name) {
          return NULL_TIMER;
      }
  
  }
  