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.alibaba.metrics.jvm;
  
  import com.alibaba.metrics.Metric;
  import com.alibaba.metrics.MetricName;
  import com.alibaba.metrics.MetricSet;
  import com.alibaba.metrics.PersistentGauge;
  
  import java.lang.management.ManagementFactory;
  import java.lang.management.RuntimeMXBean;
  import java.util.Collections;
  import java.util.HashMap;
  import java.util.Locale;
  import java.util.Map;
  
  /**
   * A set of gauges for the JVM name, vendor, and uptime.
   */
  public class JvmAttributeGaugeSet implements MetricSet {
  
      private final RuntimeMXBean runtime;
  
      /**
       * Creates a new set of gauges.
       */
      public JvmAttributeGaugeSet() {
          this(ManagementFactory.getRuntimeMXBean());
      }
  
      /**
       * Creates a new set of gauges with the given {@link RuntimeMXBean}.
       * @param runtime JVM management interface with access to system properties
       */
      public JvmAttributeGaugeSet(RuntimeMXBean runtime) {
          this.runtime = runtime;
      }
  
      @Override
      public Map<MetricName, Metric> getMetrics() {
          final Map<MetricName, Metric> gauges = new HashMap<MetricName, Metric>();
  
          gauges.put(MetricName.build("name"), new PersistentGauge<String>() {
              @Override
              public String getValue() {
                  return runtime.getName();
              }
          });
  
          gauges.put(MetricName.build("vendor"), new PersistentGauge<String>() {
              @Override
              public String getValue() {
                  return String.format(Locale.US,
                          "%s %s %s (%s)",
                          runtime.getVmVendor(),
                          runtime.getVmName(),
                          runtime.getVmVersion(),
                          runtime.getSpecVersion());
              }
          });
  
          gauges.put(MetricName.build("uptime"), new PersistentGauge<Long>() {
              @Override
              public Long getValue() {
                  return runtime.getUptime();
              }
          });
  
          return Collections.unmodifiableMap(gauges);
      }
  
      @Override
      public long lastUpdateTime() {
          return System.currentTimeMillis();
      }
  }
  