bundles/org.simantics.db.impl/src/org/simantics/db/impl/MemWatch.java

   1 package org.simantics.db.impl;
   2
   3 import java.lang.ref.WeakReference;
   4
   5 public class MemWatch {
   6     public static boolean isLowOnMemory() {
   7         return isLowOnMemory;
   8     }
   9     private static boolean DBBUG = false;
  10     private static boolean isLowOnMemory = false;
  11     @SuppressWarnings("unused")
  12     private static MemWatch memWatch = new MemWatch();
  13     private Runtime runtime = Runtime.getRuntime();
  14     @SuppressWarnings("unused")
  15     private WeakReference<Watch> ref = new WeakReference<Watch>(new Watch());
  16     class Watch {
  17         @Override
  18         protected void finalize() throws Throwable {
  19             long fre = runtime.freeMemory();
  20             long tot = runtime.totalMemory();
  21             long max = runtime.maxMemory();
  22             if (tot < max || fre > max / 20)
  23                 isLowOnMemory = false;
  24             else
  25                 isLowOnMemory = true;
  26             if (DBBUG)
  27               System.err.println("Garbage was collected using " + Thread.currentThread().getName()
  28               + " fre=" + fre + " tot=" + tot + " max=" + max
  29               + " low=" + isLowOnMemory);
  30             ref = new WeakReference<Watch>(new Watch());
  31             super.finalize();
  32         }
  33     }
  34 }