diff -u -r1.2 -r1.3
--- JetDriver.java	25 Aug 2005 05:54:51 -0000	1.2
+++ JetDriver.java	18 Sep 2007 03:46:26 -0000	1.3
@@ -12,6 +12,7 @@

 import java.util.Map;
 import org.lcsim.event.EventHeader;
 import org.lcsim.event.ReconstructedParticle;

+import org.lcsim.event.Vertex;

 import org.lcsim.util.Driver;
 import org.lcsim.util.aida.AIDA;
 

@@ -19,7 +20,7 @@

  * A simple driver which can be used to find jets from ReconstructedParticles.
  * The resuslting jets are stored in a new collection of ReconstructedParticles.
  * @author tonyj

- * @version $Id: JetDriver.java,v 1.2 2005/08/25 05:54:51 tonyj Exp $

+ * @version $Id: JetDriver.java,v 1.3 2007/09/18 03:46:26 tonyj Exp $

  */
 public class JetDriver extends Driver
 {

@@ -237,5 +238,9 @@

       {
          return null;
       }

+      public Vertex getStartVertex()
+      {
+         return null;
+      }

    }
 }

diff -N SIOVertexBlockHandler.java
--- /dev/null	1 Jan 1970 00:00:00 -0000
+++ SIOVertexBlockHandler.java	18 Sep 2007 03:46:26 -0000	1.1
@@ -0,0 +1,70 @@

+package org.lcsim.util.lcio;
+
+import hep.lcd.io.sio.SIOInputStream;
+import hep.lcd.io.sio.SIOOutputStream;
+import hep.lcd.io.sio.SIOWriter;
+
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.HashSet;
+import java.util.List;
+import java.util.Set;
+import org.lcsim.event.EventHeader;
+import org.lcsim.event.Vertex;
+
+/**
+ *
+ * @author tonyj
+ */
+class SIOVertexBlockHandler extends AbstractBlockHandler
+{
+   private static final String ALGORITHM_TYPES = "_lcio.VertexAlgorithmTypes";
+   private static final String PARAMETER_NAMES = "VertexParameterNames";
+   
+   private List<String> algorithmTypeKeys = new ArrayList<String>();
+   private List<String> parameterNameKeys = new ArrayList<String>();
+   
+   public String getType()
+   { 
+      return "Vertex"; 
+   }
+   public Class getClassForType()
+   { 
+      return Vertex.class; 
+   }
+   void addCollectionElements(LCIOEvent event, LCIOCollection collection, SIOInputStream in, int n, int version) throws IOException
+   {
+      String[] typeKeys = collection.getParameters().getStringMap().get(ALGORITHM_TYPES);
+      String[] parameterNames = collection.getParameters().getStringMap().get(PARAMETER_NAMES);
+      
+      for (int i = 0; i < n; i++)
+         collection.add(new SIOVertex(in, collection.getFlags(), version, typeKeys, parameterNames));
+   }
+   void writeCollectionElement(Object element, SIOOutputStream out, int flags) throws IOException
+   {
+      SIOVertex.write((Vertex) element, out, flags, algorithmTypeKeys, parameterNameKeys);
+   }
+   
+   public void writeBlock(SIOWriter writer, List collection, EventHeader.LCMetaData md) throws IOException
+   {
+      Set<String> types = new HashSet<String>();
+      Set<String> names = new HashSet<String>();
+      for (Vertex v : (List<Vertex>) collection)
+      {
+         types.add(v.getAlgorithmType());
+         for (String name : v.getParameters().keySet())
+         {
+            names.add(name);
+         }
+      }
+      algorithmTypeKeys = new ArrayList(types);
+      String[] keyStrings = new String[types.size()];
+      md.getStringParameters().put(ALGORITHM_TYPES,types.toArray(keyStrings));
+      
+      parameterNameKeys = new ArrayList(names);
+      String[] nameStrings = new String[names.size()];
+      md.getStringParameters().put(PARAMETER_NAMES,names.toArray(nameStrings));     
+      
+      super.writeBlock(writer, collection, md);
+   }
+}

diff -N SIOVertex.java
--- /dev/null	1 Jan 1970 00:00:00 -0000
+++ SIOVertex.java	18 Sep 2007 03:46:26 -0000	1.1
@@ -0,0 +1,117 @@

+package org.lcsim.util.lcio;
+
+import hep.lcd.io.sio.SIOInputStream;
+import hep.lcd.io.sio.SIOOutputStream;
+import hep.lcd.io.sio.SIORef;
+import hep.physics.matrix.SymmetricMatrix;
+import hep.physics.vec.BasicHep3Vector;
+import hep.physics.vec.Hep3Vector;
+
+import java.io.IOException;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+import org.lcsim.event.ReconstructedParticle;
+import org.lcsim.event.Vertex;
+
+/**
+ *
+ * @author Tony Johnson
+ * @version $Id: SIOVertex.java,v 1.1 2007/09/18 03:46:26 tonyj Exp $
+ */
+class SIOVertex implements Vertex
+{
+   private int primary;
+   private String type;
+   private double chi2;
+   private double probability;
+   private SIORef recPRef;
+   private SymmetricMatrix errorMatrix;
+   private Hep3Vector position;
+   private Map<String,Double> parameters;
+   
+   SIOVertex(SIOInputStream in, int flag, int version, String[] keys, String[] parameterNames) throws IOException
+   {
+      this.primary = in.readInt();
+      this.type = keys[in.readInt()];
+      this.chi2 = in.readFloat();
+      this.probability = in.readFloat();
+      this.position = new BasicHep3Vector(in.readFloat(),in.readFloat(),in.readFloat());
+      
+      double[] covMatrix = new double[6];
+      for (int i=0; i<covMatrix.length; i++) covMatrix[i] = in.readFloat();
+      errorMatrix = new SymmetricMatrix(3,covMatrix,true);
+      int n = in.readInt();
+      this.parameters = new HashMap<String,Double>(n);
+      for (int i=0; i<n; i++) 
+      {
+         Float f = in.readFloat();
+         if (!f.isNaN()) parameters.put(parameterNames[i],Double.valueOf(f));
+      }
+      recPRef = in.readPntr();
+      in.readPTag(this);
+   }
+   static void write(Vertex v, SIOOutputStream out, int flag,  List<String> keys, List<String> parameterNames) throws IOException
+   {
+      out.writeInt(v.isPrimary()?1:0);
+      out.writeInt(keys.indexOf(v.getAlgorithmType()));
+      
+      out.writeFloat((float) v.getChi2());
+      out.writeFloat((float) v.getProbability());
+      Hep3Vector vec = v.getPosition();
+      out.writeFloat((float) vec.x());
+      out.writeFloat((float) vec.y());
+      out.writeFloat((float) vec.z());
+      double[] covMatrix = v.getCovMatrix().asPackedArray(true);
+      for (int i=0; i<6; i++) out.writeFloat((float) covMatrix[i]);
+      Map<String,Double> pars = v.getParameters();
+      out.writeInt(parameterNames.size());
+      for (String name : parameterNames) 
+      {
+         Double d = pars.get(name);
+         out.writeFloat(d==null ? Float.NaN : d.floatValue());
+      }
+      out.writePntr(v.getAssociatedParticle());
+      out.writePTag(v);
+   }
+   
+   public boolean isPrimary()
+   {
+      return primary != 0;
+   }
+   
+   public String getAlgorithmType()
+   {
+      return type;
+   }
+   
+   public double getChi2()
+   {
+      return chi2;
+   }
+   
+   public double getProbability()
+   {
+      return probability;
+   }
+   
+   public Hep3Vector getPosition()
+   {
+      return position;
+   }
+   
+   public SymmetricMatrix getCovMatrix()
+   {
+      return errorMatrix;
+   }
+   
+   public Map<String, Double> getParameters()
+   {
+      return parameters;
+   }
+   
+   public ReconstructedParticle getAssociatedParticle()
+   {
+      return (ReconstructedParticle) recPRef.getObject();
+   }
+}

diff -u -r1.5 -r1.6
--- SIOReconstructedParticle.java	11 Sep 2007 21:01:29 -0000	1.5
+++ SIOReconstructedParticle.java	18 Sep 2007 03:46:26 -0000	1.6
@@ -15,18 +15,20 @@

 import org.lcsim.event.ParticleID;
 import org.lcsim.event.ReconstructedParticle;
 import org.lcsim.event.Track;

+import org.lcsim.event.Vertex;

 import org.lcsim.event.base.BaseReconstructedParticle;
 
 /**
  *
  * @author Tony Johnson

- * @version $Id: SIOReconstructedParticle.java,v 1.5 2007/09/11 21:01:29 tonyj Exp $

+ * @version $Id: SIOReconstructedParticle.java,v 1.6 2007/09/18 03:46:26 tonyj Exp $

  */
 class SIOReconstructedParticle extends BaseReconstructedParticle
 {
    private List<SIORef> tempParticles;
    private List<SIORef> tempTracks;
    private List<SIORef> tempClusters;

+   private SIORef tempVertex;

    
    SIOReconstructedParticle(SIOInputStream in, int flags, int version) throws IOException
    {

@@ -72,8 +74,8 @@

       }
       if (version > 1007)
       {

-         // Fixme: This is not currently accessible
-         SIORef startVertex = in.readPntr();

+         tempVertex = in.readPntr();
+         _vertex = null;

       }
       in.readPTag(this);
    }

@@ -108,6 +110,7 @@

       List<Cluster> clusters = particle.getClusters();
       out.writeInt(clusters.size());
       for (Cluster cluster : clusters) out.writePntr(cluster);

+      out.writePntr(particle.getStartVertex());

       out.writePTag(particle);
    }
    

@@ -143,4 +146,14 @@

       }
       return _tracks == null ? Collections.<Track>emptyList() : _tracks;
    }

+
+   public Vertex getStartVertex()
+   {
+      if (_vertex == null && tempVertex != null)
+      {
+         _vertex = (Vertex) tempVertex.getObject();
+         tempVertex = null;
+      }
+      return super.getStartVertex();
+   }

 }

diff -u -r1.6 -r1.7
--- AbstractBlockHandler.java	26 Aug 2005 00:26:56 -0000	1.6
+++ AbstractBlockHandler.java	18 Sep 2007 03:46:26 -0000	1.7
@@ -43,7 +43,6 @@

       Map<String,int[]> intMap = md.getIntegerParameters();
       Map<String,float[]> floatMap = md.getFloatParameters();
       Map<String,String[]> stringMap = md.getStringParameters();

-      SIOLCParameters colParameters = null;

       SIOLCParameters.write(intMap,floatMap,stringMap,out);
       out.writeInt(collection.size());
       for (Object element : collection)

@@ -53,4 +52,4 @@

       out.close();
    }
    abstract void writeCollectionElement(Object element, SIOOutputStream out, int flags) throws IOException;

-}

\ No newline at end of file

+}

diff -u -r1.8 -r1.9
--- LCIOConstants.java	4 Jun 2007 06:50:39 -0000	1.8
+++ LCIOConstants.java	18 Sep 2007 03:46:26 -0000	1.9
@@ -7,7 +7,7 @@

 public interface LCIOConstants
 {
    int MAJORVERSION = 1;

-   int MINORVERSION = 7;

+   int MINORVERSION = 8;

    
    // bits in flag words
    // SimCalorimeterHit (CH)

diff -u -r1.12 -r1.13
--- HandlerManager.java	4 Jun 2007 06:50:39 -0000	1.12
+++ HandlerManager.java	18 Sep 2007 03:46:26 -0000	1.13
@@ -39,6 +39,7 @@

       register(new SIORawTrackerHitBlockHandler());
       register(new SIOTrackerDataBlockHandler());
       register(new SIOTrackerPulseBlockHandler());

+      register(new SIOVertexBlockHandler());

    }
    static HandlerManager instance()
    {

diff -N Vertex.java
--- /dev/null	1 Jan 1970 00:00:00 -0000
+++ Vertex.java	18 Sep 2007 03:46:27 -0000	1.1
@@ -0,0 +1,46 @@

+package org.lcsim.event;
+
+import hep.physics.matrix.SymmetricMatrix;
+import hep.physics.vec.Hep3Vector;
+import java.util.Map;
+
+/**
+ * A representation of a vertex
+ * @author tonyj
+ */
+public interface Vertex
+{
+    /** Checks if the Vertex is the primary vertex of the event.
+     *  Only one primary vertex per event is allowed
+     */
+    boolean isPrimary();
+
+    /** Type code for the algorithm that has been used to create the vertex - check/set the 
+     *  collection parameters AlgorithmName and  AlgorithmType.
+     */
+    String getAlgorithmType();
+
+     /** Chi squared of the vertex fit.
+     */
+    double getChi2();
+
+    /** Probability of the vertex fit.
+     */
+    double getProbability();
+
+    /** Position of the vertex
+     */
+    Hep3Vector getPosition();
+
+    /** Covariance matrix of the position 
+     */
+    SymmetricMatrix getCovMatrix();
+
+    /** Additional parameters related to this vertex.
+     */
+    Map<String,Double> getParameters();
+
+    /** Returns Reconstructed Particle associated to the Vertex
+     */
+    ReconstructedParticle getAssociatedParticle(); 
+}

diff -u -r1.2 -r1.3
--- ReconstructedParticle.java	28 Jun 2006 04:48:31 -0000	1.2
+++ ReconstructedParticle.java	18 Sep 2007 03:46:27 -0000	1.3
@@ -7,7 +7,7 @@

 /**
  * Represents a fully reconstructed particle.
  * @author tonyj

- * @version $Id: ReconstructedParticle.java,v 1.2 2006/06/28 04:48:31 jstrube Exp $

+ * @version $Id: ReconstructedParticle.java,v 1.3 2007/09/18 03:46:27 tonyj Exp $

  */
 public interface ReconstructedParticle
 {

@@ -89,5 +89,10 @@

    /**Returns this particles momentum and energy as a four vector
     */
    HepLorentzVector asFourVector();

+   
+   /**
+    * Returns the start vertex, or <code>null</code> if none is known
+    */
+   public Vertex getStartVertex();

 }
 

diff -u -r1.2 -r1.3
--- CheatReconstructedParticle.java	28 Sep 2005 00:35:50 -0000	1.2
+++ CheatReconstructedParticle.java	18 Sep 2007 03:46:27 -0000	1.3
@@ -21,6 +21,7 @@

 import org.lcsim.event.ReconstructedParticle;
 import org.lcsim.event.Track;
 import org.lcsim.event.MCParticle;

+import org.lcsim.event.Vertex;

 import org.lcsim.recon.ztracking.cheater.CheatTrack;
 import org.lcsim.recon.cluster.cheat.CheatCluster;
 

@@ -221,5 +222,10 @@

         StringBuffer sb = new StringBuffer("CheatReconstructedParticle: \n");
         sb.append("E: "+getEnergy());
         return sb.toString();

+    } 
+
+    public Vertex getStartVertex()
+    {
+        return null; 

     }
 }

diff -u -r1.10 -r1.11
--- MCFastReconstructedParticle.java	16 Feb 2007 01:34:36 -0000	1.10
+++ MCFastReconstructedParticle.java	18 Sep 2007 03:46:27 -0000	1.11
@@ -1,5 +1,6 @@

 package org.lcsim.mc.fast.reconstructedparticle;
 

+import org.lcsim.event.Vertex;

 import org.lcsim.mc.fast.MCFast;
 import hep.physics.vec.BasicHep3Vector;
 import hep.physics.vec.BasicHepLorentzVector;

@@ -233,4 +234,9 @@

         sb.append("E: "+getEnergy());
         return sb.toString();
     }

+
+    public Vertex getStartVertex()
+    {
+        return null;
+    }

 }