code: /*
   * Copyright © 2014-2017 EntIT Software LLC, a Micro Focus company (L.P.)
   *
   * 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.
   */
  package io.cloudslang.worker.monitor.metrics;
  
  import io.cloudslang.worker.monitor.metric.WorkerPerfMetric;
  import io.cloudslang.worker.monitor.service.WorkerPerformanceMetric;
  import org.apache.commons.lang3.tuple.Pair;
  import oshi.software.os.OSProcess;
  
  import java.io.Serializable;
  
  import static io.cloudslang.worker.monitor.metric.WorkerPerfMetric.formatTo2Decimal;
  import static io.cloudslang.worker.monitor.service.WorkerPerformanceMetric.HEAP_SIZE;
  import static java.lang.Runtime.getRuntime;
  
  public class HeapUtilizationService implements WorkerPerfMetric {
  
      @Override
      public Pair<WorkerPerformanceMetric, Serializable> measure(OSProcess crtProcess, OSProcess oldProcess) {
          return Pair.of(HEAP_SIZE, getCurrentValue());
      }
  
      public double getCurrentValue() {
          // Get current size of heap in bytes
          long totalMemory = getRuntime().totalMemory();
          long freeMemory = getRuntime().freeMemory();
          double allocatedMemory = totalMemory - freeMemory;
          long maxMemory = getRuntime().maxMemory();
          double percentageHeapUsed = (allocatedMemory / formatTo2Decimal(maxMemory)) * 100;
          return formatTo2Decimal(percentageHeapUsed);
      }
  
  
  }
  