diff -N TrackerHitSegment.java
--- /dev/null	1 Jan 1970 00:00:00 -0000
+++ TrackerHitSegment.java	25 Sep 2007 03:28:36 -0000	1.1
@@ -0,0 +1,133 @@

+package org.lcsim.contrib.onoprien.tracking.hit.base;
+
+import hep.physics.matrix.SymmetricMatrix;
+import hep.physics.vec.Hep3Vector;
+import hep.physics.vec.BasicHep3Vector;
+import hep.physics.vec.VecOp;
+
+import org.lcsim.spacegeom.SpacePoint;
+import org.lcsim.spacegeom.SpacePointVector;
+
+import org.lcsim.contrib.onoprien.tracking.geom.Sensor;
+import org.lcsim.contrib.onoprien.tracking.hit.TrackerCluster;
+import org.lcsim.contrib.onoprien.tracking.hit.TrackerHit;
+
+/**
+ * Implementation of {@link TrackerHit} suitable for representing segment-like hits.
+ * Position and covariance matrix can be supplied to the constructor in either
+ * <tt>Sensor</tt> local or global reference frame. Conversion will only be done
+ * if needed, and the results will be cached.
+ * 
+ * @author D.Onoprienko
+ * @version $Id: TrackerHitSegment.java,v 1.1 2007/09/25 03:28:36 onoprien Exp $
+ */
+public class TrackerHitSegment extends TrackerHitAdapter {
+  
+// -- Constructors :  ----------------------------------------------------------
+  
+  /**
+   * Construct a new TrackerHit.
+   * Vector and matrix supplied to the constructor will be owned by the created hit.
+   *
+   * @param cluster    {@link TrackerCluster} from which this hit was created.
+   * @param position   Position of the hit.
+   * @param length     Length of segment defining the hit.
+   * @param covMatrix  Covariance matrix
+   * @param isLocal    <tt>true</tt> if position and covariance matrix are given
+   *                   in the <tt>Sensor</tt> local reference frame, <tt>false</tt>
+   *                   if they are given in the global frame.
+   *
+   */
+  public TrackerHitSegment(TrackerCluster cluster, Hep3Vector position, double length, 
+                           SymmetricMatrix covMatrix, boolean isLocal) {
+    super(cluster);
+    if (isLocal) {
+      _posLocal = position;
+      _covLocal = covMatrix;
+    } else {
+      _posGlobal = position;
+      _covGlobal = covMatrix;      
+    }
+    _length = length;
+  }
+  
+// -- Position and covariance matrix in local coordinates :  -------------------
+  
+  /** 
+   * Returns position of the hit in local reference frame of the {@link Sensor}.
+   */
+  public Hep3Vector getLocalPosition() {
+    if (_posLocal == null) _posLocal = super.getLocalPosition();
+    return _posLocal;
+  }
+  
+  /** 
+   * Returns covariance matrix in local frame. 
+   */
+  public SymmetricMatrix getLocalCovMatrix() {
+    if (_covLocal == null) _covLocal = super.getLocalCovMatrix();
+    return _covLocal;
+  }
+  
+  /** 
+   * Returns <tt>SpacePointVector</tt> pointing from start to end of the segment 
+   * defining the hit in the local reference frame.
+   */
+  public SpacePointVector getLocalSegment() {
+    if (_segLocal == null) {
+      if (_posLocal == null) _posLocal = super.getLocalPosition();
+      Hep3Vector dif = new BasicHep3Vector(0., _length/2., 0.);
+      _segLocal = new SpacePointVector(new SpacePoint(VecOp.sub(_posLocal, dif)), 
+                                       new SpacePoint(VecOp.add(_posLocal, dif)));
+    }
+    return _segLocal;
+  }
+
+// -- Position and covariance matrix in global coordinates :  ------------------
+  
+  /**
+   * 
+   * Returns position of the hit in global reference frame.
+   */
+  public Hep3Vector getPosition() {
+    if (_posGlobal == null) _posGlobal = super.getPosition();
+    return _posGlobal;
+  }
+  
+  /** 
+   * Returns covariance matrix of the hit in global reference frame. 
+   */
+  public SymmetricMatrix getCovMatrix() {
+    if (_covGlobal == null) _covGlobal = super.getCovMatrix();
+    return _covGlobal;
+  }
+
+  /** 
+   * Returns <tt>SpacePointVector</tt> pointing from start to end of the segment 
+   * defining the hit in the global reference frame.
+   */
+  public SpacePointVector getSegment() {
+    if (_segGlobal == null) _segGlobal = super.getSegment();
+    return _segGlobal;
+  }
+
+// -- Length of segment-like hit :  --------------------------------------------
+  
+  /**
+   * 
+   * Returns length of the segment defining the hit. 
+   */
+  public double getLength() {
+    return _length;
+  }
+  
+// -- Private parts :  ---------------------------------------------------------
+
+  Hep3Vector _posLocal;
+  Hep3Vector _posGlobal;
+  SymmetricMatrix _covLocal;
+  SymmetricMatrix _covGlobal;
+  SpacePointVector _segLocal;
+  SpacePointVector _segGlobal;
+  double _length;
+}