diff -N CheckDisjoint.java
--- /dev/null	1 Jan 1970 00:00:00 -0000
+++ CheckDisjoint.java	13 Oct 2008 07:15:51 -0000	1.1
@@ -0,0 +1,60 @@

+package org.lcsim.contrib.uiowa;
+
+import java.util.*;
+import org.lcsim.util.Driver;
+import org.lcsim.event.EventHeader;
+import org.lcsim.util.*;
+import org.lcsim.event.*;
+import org.lcsim.recon.cluster.directedtree.*;
+import org.lcsim.util.hitmap.*;
+import org.lcsim.util.decision.*;
+import org.lcsim.contrib.uiowa.MuonFinder.*;
+import org.lcsim.recon.pfa.identifier.*;
+
+public class CheckDisjoint extends Driver
+{
+    String m_name1;
+    String m_name2;
+    public CheckDisjoint(String name1, String name2) {
+	m_name1 = name1;
+	m_name2 = name2;
+    }
+
+    public void process(EventHeader event) {
+	Set<Long> set1 = getHits(m_name1, event);
+	Set<Long> set2 = getHits(m_name2, event);
+	for (Long id : set1) {
+	    if (set2.contains(id)) {
+		throw new AssertionError("ERROR: Both "+m_name1+" and "+m_name2+" contain hit with ID "+id);
+	    }
+	}
+	System.out.println("OK: No overlaps between "+set1.size()+" hits in "+m_name1+" and "+set2.size()+" hits in "+m_name2);
+    }
+
+    private Set<Long> getHits(String name, EventHeader event) {
+	Set<Long> output = new HashSet<Long>();
+	Object o = event.get(name);
+	if (o instanceof HitMap) {
+	    HitMap tmpMap = (HitMap)(o);
+	    output.addAll(tmpMap.keySet());
+	} else if (o instanceof Collection) {
+	    List tmpList = (List)(o);
+	    for (Object subObj : tmpList) {
+		if (subObj instanceof CalorimeterHit) {
+		    CalorimeterHit hit = (CalorimeterHit)(subObj);
+		    output.add(hit.getCellID());
+		} else if (subObj instanceof Cluster) {
+		    Cluster clus = (Cluster)(subObj);
+		    for (CalorimeterHit hit : clus.getCalorimeterHits()) {
+			output.add(hit.getCellID());
+		    }
+		} else {
+		    throw new AssertionError("ERROR: Sub-object type "+subObj.getClass().getName()+" not recognized.");
+		}
+	    }
+	} else {
+	    throw new AssertionError("ERROR: Object type "+o.getClass().getName()+" not recognized.");
+	}
+	return output;
+    }
+}