diff -u -r1.10 -r1.11
--- TrackerDigiDriver.java	9 Aug 2012 21:14:33 -0000	1.10
+++ TrackerDigiDriver.java	9 Aug 2012 21:51:26 -0000	1.11
@@ -30,7 +30,7 @@

  * algorithm like Seed Tracker.
  * 
  * @author jeremym

- * @version $Id: TrackerDigiDriver.java,v 1.10 2012/08/09 21:14:33 meeg Exp $

+ * @version $Id: TrackerDigiDriver.java,v 1.11 2012/08/09 21:51:26 meeg Exp $

  */
 public class TrackerDigiDriver extends Driver {
     // Debug switch for development.

@@ -267,28 +267,30 @@

         List<RawTrackerHit> rawHits = new ArrayList<RawTrackerHit>();
         List<SiTrackerHit> stripHits1D = new ArrayList<SiTrackerHit>();
 

-        // Make raw hits.
-        for (SiSensor sensor : processSensors) {
-            rawHits.addAll(stripDigitizer.makeHits(sensor));
-        }

+        if (event.hasCollection(SimTrackerHit.class, this.readoutCollectionName)) {
+            // Make raw hits.
+            for (SiSensor sensor : processSensors) {
+                rawHits.addAll(stripDigitizer.makeHits(sensor));
+            }

-        // Make strip hits.
-        for (SiSensor sensor : processSensors) {
-            stripHits1D.addAll(stripClusterer.makeHits(sensor));
-        }

+            // Make strip hits.
+            for (SiSensor sensor : processSensors) {
+                stripHits1D.addAll(stripClusterer.makeHits(sensor));
+            }

-        // Debug prints.
-        if (debug) {
-            if (event.hasCollection(SimTrackerHit.class, this.readoutCollectionName)) {
-                List<SimTrackerHit> simHits = event.get(SimTrackerHit.class, this.readoutCollectionName);
-                System.out.println("SimTrackerHit collection " + this.readoutCollectionName + " has " + simHits.size() + " hits.");
-                System.out.println("RawTrackerHit collection " + this.rawTrackerHitOutputCollectionName + " has " + rawHits.size() + " hits.");
-                System.out.println("TrackerHit collection " + this.stripHitOutputCollectionName + " has " + stripHits1D.size() + " hits.");
-            } else {
-                System.out.println("SimTrackerHit collection " + this.readoutCollectionName + " not found.");

+            // Debug prints.
+            if (debug) {
+                if (event.hasCollection(SimTrackerHit.class, this.readoutCollectionName)) {
+                    List<SimTrackerHit> simHits = event.get(SimTrackerHit.class, this.readoutCollectionName);
+                    System.out.println("SimTrackerHit collection " + this.readoutCollectionName + " has " + simHits.size() + " hits.");
+                    System.out.println("RawTrackerHit collection " + this.rawTrackerHitOutputCollectionName + " has " + rawHits.size() + " hits.");
+                    System.out.println("TrackerHit collection " + this.stripHitOutputCollectionName + " has " + stripHits1D.size() + " hits.");
+                } else {
+                    System.out.println("SimTrackerHit collection " + this.readoutCollectionName + " not found.");
+                }

             }
         }

-

+        

         // Put output hits into collection.
         int flag = LCIOUtil.bitSet(0, 31, true); // Turn on 64-bit cell ID.
         event.put(this.rawTrackerHitOutputCollectionName, rawHits, RawTrackerHit.class, flag, toString());