add buffering for the performance graph to avoid ConcurrentModificationException

closes: http://forum.yacy-websuche.de/viewtopic.php?f=6&t=628

git-svn-id: https://svn.berlios.de/svnroot/repos/yacy/trunk@4281 6c8d7289-2bf4-0310-a012-ef5d649a1542

source/de/anomic/plasma/plasmaProfiling.java

@@ -26,6 +26,7 @@
 
 package de.anomic.plasma;
 
+import java.util.ConcurrentModificationException;
 import java.util.Iterator;
 
 import de.anomic.server.serverProfiling;
@@ -35,6 +36,8 @@ import de.anomic.ymage.ymageMatrix;
 
 public class plasmaProfiling {
     
+    private static ymageChart bufferChart = null;
+
     public static long lastPPMUpdate = System.currentTimeMillis()- 30000;
 
     public static void updateIndexedPage(plasmaSwitchboardQueue.Entry entry) {
@@ -85,6 +88,7 @@ public class plasmaProfiling {
         long time, now = System.currentTimeMillis(), bytes;
         int x0 = 1, x1, y0 = 0, y1, ppm;
         serverProfiling.Event event;
+        try {
             while (i.hasNext()) {
                 event = (serverProfiling.Event) i.next();
                 time = event.time - now;
@@ -113,6 +117,10 @@ public class plasmaProfiling {
                 if (x0 < 0) chart.chartLine(ymageChart.DIMENSION_BOTTOM, ymageChart.DIMENSION_RIGHT, x0, y0, x1, y1);
                 x0 = x1; y0 = y1;
             }
+            bufferChart = chart;
+        } catch (ConcurrentModificationException cme) {
+            chart = bufferChart;
+        }
         
         return chart;
     }