code: /**
   * This file is part of Eclipse Steady.
   *
   * 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.
   *
   * SPDX-License-Identifier: Apache-2.0
   * SPDX-FileCopyrightText: Copyright (c) 2018-2020 SAP SE or an SAP affiliate company and Eclipse Steady contributors
   */
  package org.eclipse.steady.shared.util;
  
  import org.apache.logging.log4j.Logger;
  
  /**
   * <p>MemoryMonitor class.</p>
   */
  public class MemoryMonitor implements Runnable {
  
    private static final Logger log =
        org.apache.logging.log4j.LogManager.getLogger(MemoryMonitor.class);
  
    private long memoSleepTimeMs = 2000; // Every  2 seconds
    private long memoPrintTimeMs = 60000; // Every 60 seconds
    private boolean continueMonitoring = true;
    private Runtime runtime = null;
  
    private long jvmMax = -1;
    private long maxUsed = -1;
    private double avgUsed = -1;
  
    /**
     * <p>Constructor for MemoryMonitor.</p>
     */
    public MemoryMonitor() {
      this.runtime = Runtime.getRuntime();
      this.jvmMax = this.runtime.maxMemory();
    }
  
    /** {@inheritDoc} */
    @Override
    public void run() {
      long mem_total = 0, mem_free = 0, mem_used = 0, sum_used = 0, no_samples = 0, waited = 0;
      try {
        while (this.continueMonitoring) {
  
          // Sleep defined time
          Thread.sleep(this.memoSleepTimeMs);
          waited += this.memoSleepTimeMs;
  
          // Monitor mem consumption
          mem_total = this.runtime.totalMemory();
          mem_free = this.runtime.freeMemory();
          mem_used = mem_total - mem_free;
  
          // Update stats
          no_samples++;
          sum_used += mem_used;
          this.avgUsed = (double) sum_used / (double) no_samples;
          if (mem_used > this.maxUsed) this.maxUsed = mem_used;
  
          // Print?
          if (waited >= this.memoPrintTimeMs) {
            waited = 0;
            MemoryMonitor.log.info(
                "Memory consumption (used/avg): ["
                    + StringUtil.byteToMBString(mem_used)
                    + "/"
                    + StringUtil.byteToMBString(this.avgUsed)
                    + "], JVM (free/total/max): ["
                    + StringUtil.byteToMBString(mem_free)
                    + "/"
                    + StringUtil.byteToMBString(mem_total)
                    + "/"
                    + StringUtil.byteToMBString(this.jvmMax)
                    + "]");
          }
        }
      } catch (InterruptedException e) {
        MemoryMonitor.log.error("Memory monitor interrupted:" + e.getMessage());
      }
    }
  
    /**
     * <p>stop.</p>
     */
    public void stop() {
      this.continueMonitoring = false;
    }
    /**
     * <p>Getter for the field <code>jvmMax</code>.</p>
     *
     * @return a long.
     */
    public long getJvmMax() {
      return this.jvmMax;
    }
    /**
     * <p>Getter for the field <code>maxUsed</code>.</p>
     *
     * @return a long.
     */
    public long getMaxUsed() {
      return this.maxUsed;
    }
    /**
     * <p>Getter for the field <code>avgUsed</code>.</p>
     *
     * @return a double.
     */
    public double getAvgUsed() {
      return this.avgUsed;
    }
  }
  