cdmlib-commons/src/main/java/eu/etaxonomy/cdm/common/JvmMonitor.java

   1 /**
   2 * Copyright (C) 2016 EDIT
   3 * European Distributed Institute of Taxonomy
   4 * http://www.e-taxonomy.eu
   5 *
   6 * The contents of this file are subject to the Mozilla Public License Version 1.1
   7 * See LICENSE.TXT at the top of this package for the full license terms.
   8 */
   9 package eu.etaxonomy.cdm.common;
  10
  11 import java.lang.management.GarbageCollectorMXBean;
  12 import java.lang.management.ManagementFactory;
  13 import java.lang.management.MemoryMXBean;
  14 import java.lang.management.MemoryUsage;
  15 import java.util.List;
  16
  17 import org.apache.logging.log4j.LogManager;
  18 import org.apache.logging.log4j.Logger;
  19
  20 /**
  21  * @author a.kohlbecker
  22  * @since Jul 1, 2016
  23  */
  24 public class JvmMonitor {
  25
  26     public static final Logger logger = LogManager.getLogger();
  27
  28     private long gcTimeLast = 0;
  29
  30     private long lastCheckTime = 0;
  31
  32     /**
  33      * Returns the sum of approximate accumulated collection elapsed time in milliseconds
  34      * as reported by all garbage collectors.
  35      *
  36      * This method returns -1 if the collection elapsed time is undefined.
  37      *
  38      * @return
  39      */
  40     public long gcTime() {
  41         List<GarbageCollectorMXBean> gcMXBeans = ManagementFactory.getGarbageCollectorMXBeans();
  42
  43         //logger.setLevel(Level.DEBUG);
  44
  45         long gcTimeSum = -1;
  46         long collectorGcTime;
  47         for(GarbageCollectorMXBean gcMXBean : gcMXBeans){
  48                 if(gcTimeSum == -1) {
  49                     gcTimeSum = 0;
  50                 }
  51                 collectorGcTime = gcMXBean.getCollectionTime();
  52                 logger.debug("cgMxBean: " + gcMXBean.getName()
  53                         + " gcTime = " + collectorGcTime
  54                         + " gcCount = " + gcMXBean.getCollectionCount());
  55                 if(collectorGcTime != -1) {
  56                     // only sum up if the time is defined
  57                     gcTimeSum += gcMXBean.getCollectionTime();
  58                 }
  59         }
  60         logger.debug("gcTimeSum = " + gcTimeSum);
  61         return gcTimeSum;
  62
  63     }
  64
  65     public MemoryUsage getHeapMemoryUsage(){
  66
  67         MemoryMXBean memoryMXBean = ManagementFactory.getMemoryMXBean();
  68         if(memoryMXBean != null){
  69             logger.debug("HeapMemoryUsage: " + memoryMXBean.getHeapMemoryUsage());
  70             return memoryMXBean.getHeapMemoryUsage();
  71         }
  72         return null;
  73     }
  74
  75
  76     public boolean hasFreeHeap(long freeHeapLimit) {
  77
  78         if(!_hasFreeHeap(freeHeapLimit)) {
  79             Runtime.getRuntime().gc();
  80             return _hasFreeHeap(freeHeapLimit);
  81         }
  82         return true;
  83     }
  84
  85     private boolean _hasFreeHeap(long freeHeapLimit) {
  86         long freeHeap = getFreeHeap(false);
  87         return freeHeap > freeHeapLimit;
  88     }
  89
  90     public long getFreeHeap(boolean gcBeforeMeasure) {
  91         if(gcBeforeMeasure) {
  92             Runtime.getRuntime().gc();
  93         }
  94         MemoryUsage heapUsage = getHeapMemoryUsage();
  95         long freeHeap =  heapUsage.getMax() - heapUsage.getUsed();
  96         return freeHeap;
  97     }
  98
  99     /**
 100      * Returns the gcTime in milliseconds as obtained through {@link #gctime()} of the
 101      * time interval since this method has been called the last time and now.
 102      *
 103      * @return
 104      */
 105     public long getGCtimeSiceLastCheck() {
 106         long gcTimeNow = gcTime();
 107         long gcTimeSince = gcTimeNow - gcTimeLast;
 108         gcTimeLast = gcTimeNow;
 109         lastCheckTime  = System.currentTimeMillis();
 110         return gcTimeSince;
 111     }
 112
 113     /**
 114      * Returns the time spend in gc as proportion (0.0 to 1.0) of the
 115      * time interval since this method has been called the last time and now.
 116      *
 117      * @return
 118      */
 119     public double getGCRateSiceLastCheck() {
 120
 121         long gcTimeSince = getGCtimeSiceLastCheck();
 122         long timeDiff = System.currentTimeMillis() - lastCheckTime;
 123         double gcRate = gcTimeSince / (double) timeDiff;
 124         return gcRate;
 125     }
 126
 127
 128
 129
 130 }