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 com.aliyun.odps.table.metrics;
  
  import java.util.HashMap;
  import java.util.Map;
  import java.util.Optional;
  
  /**
   * A collection of metrics.
   */
  public class Metrics {
  
      private final Map<String, Metric> metricMap = new HashMap<>();
  
      public void register(Metric metric) {
          metricMap.put(metric.name(), metric);
      }
  
      public Optional<Metric> get(String name) {
          if (metricMap.containsKey(name)) {
              return Optional.of(metricMap.get(name));
          } else {
              return Optional.empty();
          }
      }
  
      public Optional<Counter> counter(String name) {
          if (metricMap.containsKey(name)) {
              return Optional.of((Counter) metricMap.get(name));
          } else {
              return Optional.empty();
          }
      }
  
      public <T, G extends Gauge<T>> Optional<G> gauge(String name) {
          if (metricMap.containsKey(name)) {
              return Optional.of((G) metricMap.get(name));
          } else {
              return Optional.empty();
          }
      }
  
      // TODO: toString
  }
  