bundles/org.simantics.modeling.ui/src/org/simantics/modeling/ui/diagramEditor/DisposingPolicy.java

   1 package org.simantics.modeling.ui.diagramEditor;
   2
   3 import gnu.trove.map.hash.TObjectLongHashMap;
   4
   5 import java.util.ArrayDeque;
   6
   7 import org.eclipse.swt.widgets.Display;
   8
   9
  10 public class DisposingPolicy {
  11
  12     public static final boolean DEBUG = false;
  13
  14     public static final int MAX_QUEUE_LENGTH = 8;
  15     public static final long DISPOSE_TIME = 30000L; // ms
  16     public static final long MIN_DELAY = 200L; // ms
  17
  18     private ArrayDeque<Runnable> disposerQueue = new ArrayDeque<Runnable>(MAX_QUEUE_LENGTH);
  19     private TObjectLongHashMap<Runnable> disposeTime =
  20             new TObjectLongHashMap<Runnable>(MAX_QUEUE_LENGTH);
  21     private Runnable currentlyScheduled = null;
  22
  23     private Runnable disposeOne = new Runnable() {
  24         @Override
  25         public void run() {
  26             if(!disposerQueue.isEmpty()) {
  27                 Runnable runnable = disposerQueue.removeFirst();
  28                 disposeTime.remove(runnable);
  29                 currentlyScheduled = null;
  30                 runnable.run();
  31                 if(DEBUG)
  32                     System.out.println("Executed disposer " + runnable);
  33                 if(!disposerQueue.isEmpty())
  34                     scheduleDispose();
  35             }
  36         }
  37     };
  38
  39     private void scheduleDispose() {
  40         currentlyScheduled = disposerQueue.peekFirst();
  41         long delay = Math.max(
  42                 disposeTime.get(currentlyScheduled) - System.currentTimeMillis(),
  43                 MIN_DELAY);
  44         Display.getCurrent().timerExec((int)delay, disposeOne);
  45         if(DEBUG)
  46             System.out.println("Scheduled disposer " + currentlyScheduled + " in " + delay + " ms");
  47     }
  48
  49     /**
  50      * Runs the disposer either after DISPOSE_TIME or when there are
  51      * more than MAX_QUEUE_LENGTH disposers active and this is first
  52      * of them (by activation order). This method must be called from
  53      * UI thread.
  54      */
  55     public void addDisposer(Runnable disposer) {
  56         if(DEBUG)
  57             System.out.println("Added disposer " + disposer);
  58         if(disposeTime.contains(disposer))
  59             return;
  60         if(disposerQueue.size() >= MAX_QUEUE_LENGTH)
  61             disposeOne.run();
  62         disposerQueue.addLast(disposer);
  63         disposeTime.put(disposer, System.currentTimeMillis()+DISPOSE_TIME);
  64         if(disposerQueue.size() == 1)
  65             scheduleDispose();
  66     }
  67
  68     /**
  69      * Cancels a disposer added before. This method must be called from
  70      * UI thread.
  71      */
  72     public void removeDisposer(Runnable disposer) {
  73         if(DEBUG)
  74             System.out.println("Removed disposer " + disposer);
  75         disposerQueue.remove(disposer);
  76         disposeTime.remove(disposer);
  77         if(disposer == currentlyScheduled) {
  78             currentlyScheduled = null;
  79             if(!disposerQueue.isEmpty())
  80                 scheduleDispose();
  81         }
  82     }
  83
  84 }