Memory of last datamatrix in case puck detection is flickering during load.

src/main/java/ch/psi/mxsc/Controller.java

@@ -701,6 +701,9 @@ public class Controller {
                 if (isDoorClosed()){
                     return;
                 }
+                insertedPuckDatamatrix = null;
+                removedPuck = null;
+                
             } else {                
                 Controller.getInstance().setLaserPos((Puck)null);
             }
@@ -781,6 +784,7 @@ public class Controller {
             System.out.println("Detected Puck: " + datamatrix);
             onPuckScanned(datamatrix);
         }
+        removedPuck = null;
     }
 
     public void onSampleBarcode(String datamatrix) {
@@ -808,19 +812,28 @@ public class Controller {
             currentDetection = detection;
         }
     }
+    String insertedPuckDatamatrix;
+    Puck removedPuck;    
 
     public void onPuckInserted(Puck puck) {
         playSound("mounted");
         String datamatrix = getMainFrame().getPuckDatamatrix();
-        logPuckDetectionChange(puck, true);
+        logPuckDetectionChange(puck, true);        
         onPuckScanned(null);
-        onPuckMounted(puck, datamatrix);        
+        if ((datamatrix==null) || (datamatrix.isBlank())){
+            if (puck == removedPuck){
+                datamatrix = insertedPuckDatamatrix;
+            }
+        }
+        onPuckMounted(puck, datamatrix);    
+        insertedPuckDatamatrix = datamatrix;
+        removedPuck = null;
     }
 
     public void onPuckRemoved(Puck puck) {
         playSound("unmounted");
         logPuckDetectionChange(puck, false);
-        onPuckUnmounted(puck);        
+        onPuckUnmounted(puck);         
     }
 
     void linkPuckDatamatrix(Puck puck, String datamatrix, boolean showMessage) {
@@ -1021,6 +1034,7 @@ public class Controller {
             } else {
                 linkPuckDatamatrix(puck, null, true);
             }
+            removedPuck = puck;
         }
     }