diff -u -r1.28 -r1.29
--- DetectorElement.java	23 May 2007 00:09:15 -0000	1.28
+++ DetectorElement.java	25 May 2007 20:16:26 -0000	1.29
@@ -13,7 +13,7 @@

  * Implementation of {@link IDetectorElement}.
  * 
  * @author Jeremy McCormick

- * @version $Id: DetectorElement.java,v 1.28 2007/05/23 00:09:15 jeremy Exp $

+ * @version $Id: DetectorElement.java,v 1.29 2007/05/25 20:16:26 jeremy Exp $

  */
 public class DetectorElement 
 extends Named

@@ -546,4 +546,20 @@

         this.parameters = parameters;
     }
     

+    /**
+     * Default implementation of {@link IDetectorElement#findDetectorElement(IIdentifier)}.
+     * Specific types of {@link IDetectorElement}s can override the default scheme. 
+     */
+    public IDetectorElementContainer findDetectorElement(IIdentifier id)
+    {
+        IDetectorElementContainer search = DetectorElementStore.getInstance().find(id);
+        for (IDetectorElement de : search)
+        {
+            if (!isDescendant(de))
+            {
+                search.remove(de);
+            }
+        }
+        return search;
+    }      

 }

\ No newline at end of file

diff -u -r1.6 -r1.7
--- DetectorElementContainer.java	23 May 2007 00:09:15 -0000	1.6
+++ DetectorElementContainer.java	25 May 2007 20:16:26 -0000	1.7
@@ -13,38 +13,83 @@

 extends ArrayList<IDetectorElement>
 implements IDetectorElementContainer
 {       

-    public IDetectorElement get(String name)

+    public IDetectorElementContainer find(String name)

     {

-        IDetectorElement search=null;

+        IDetectorElementContainer matches = new DetectorElementContainer();

         for ( IDetectorElement de : this )
         {

-            if ( de.getName().equals(name))

+            if (de.getName().equals(name))

             {

-                search = de;
-                break;

+                matches.add(de);

             }
         }

-        return search;

+        return matches;

     }   

-        
-    public boolean contains(String name)

+    
+    public IDetectorElementContainer find(IIdentifier id)

     {

-        return get(name) != null;

+        IDetectorElementContainer matches = new DetectorElementContainer();
+        if (id != null) 
+        {
+            for (IDetectorElement de : this)
+            {
+                if (de.getIdentifier() != null)
+                {
+                    if (de.getIdentifier().equals(id))
+                    {
+                        matches.add(de);
+                    }
+                }
+            }
+        }
+        return matches;

     }

-    
-    public boolean add(IDetectorElement de)

+                
+    public IDetectorElementContainer find(Class<? extends IDetectorElement> klass)

     {

-        if ( contains(de) )

+        DetectorElementContainer matches = new DetectorElementContainer();
+        for (IDetectorElement de : this)
+        {
+            for (Class checkClass : de.getClass().getClasses() )
+            {
+                if (checkClass.equals(klass))
+                {
+                    matches.add(de);
+                }
+            }
+        }
+        return matches;
+    }   
+
+    /**
+     * Current implementation does not allow duplicate name, id, or object.
+     */
+    public boolean add(IDetectorElement de)
+    {                        
+        if (de == null)

         {

-            throw new IllegalArgumentException("The DetectorElement <"+de.getName()+"> is already registered!");

+            throw new IllegalArgumentException("The DetectorElement argument points to null!");

         }

-        
-        if ( get(de.getName()) != null ) 

+
+        if (contains(de))

         {

-            throw new IllegalArgumentException("There is already a DetectorElement called <"+de.getName()+"> in this container!");

+            throw new IllegalArgumentException("The DetectorElement called <"+de.getName()+"> is already registered!");
+        }        
+
+        if (find(de.getName()).size() > 0)
+        {
+            throw new IllegalArgumentException("Duplicate DetectorElement name <"+de.getName()+">.");

         }
         

-        super.add(de);            

+        if (de.getIdentifier() != null)
+        {
+            if (find(de.getIdentifier()).size() > 0)
+            {
+                throw new IllegalArgumentException("Duplicate identifier <"+de.getIdentifier().toString()+">.");
+            }
+        }       
+        
+        super.add(de);

         return true;
     }
 }

\ No newline at end of file

diff -u -r1.4 -r1.5
--- DetectorElementStore.java	23 May 2007 00:09:15 -0000	1.4
+++ DetectorElementStore.java	25 May 2007 20:16:26 -0000	1.5
@@ -22,23 +22,28 @@

 		return store;
 	}
     

-    public IDetectorElement findDetectorElement(IIdentifier id)
-    {        
-        return cache.get(id.getValue());
-    }    
-    

     public boolean add(IDetectorElement de)

-    {            
-        if ( de.getIdentifier() != null )

+    {
+        IIdentifier id = de.getIdentifier();
+        if (id != null)

         {

-            if ( cache.get( de.getIdentifier() ) != null )

+            if (cache.get(id.getValue()) == null)
+            {
+                cache.put(id.getValue(), de);
+            }
+            else 

             {

-                throw new IllegalArgumentException("The identifier <" + de.getIdentifier().toString() + "> on DetectorElement <" + de.getName() + "> already exists.");

+                throw new IllegalArgumentException("Already have cached DetectorElement for id <"+de.getIdentifier()+">.");

             }

-            cache.put(de.getIdentifier().getValue(), de);

         }

-        super.add(de);

         return true;
     }
     

+    public IDetectorElementContainer find(IIdentifier id)
+    {  
+        IDetectorElementContainer match = new DetectorElementContainer();
+        IDetectorElement lookup = cache.get(id.getValue());
+        if (lookup != null) match.add(lookup);
+        return match;
+    }                

 }

\ No newline at end of file

diff -u -r1.18 -r1.19
--- IDetectorElement.java	9 May 2007 00:59:57 -0000	1.18
+++ IDetectorElement.java	25 May 2007 20:16:26 -0000	1.19
@@ -26,7 +26,7 @@

  * 
  * @author jeremym
  * @author tknelson

- * @version $Id: IDetectorElement.java,v 1.18 2007/05/09 00:59:57 jeremy Exp $

+ * @version $Id: IDetectorElement.java,v 1.19 2007/05/25 20:16:26 jeremy Exp $

  */
 public interface IDetectorElement 
 extends IIdentifiable, INamed

@@ -115,7 +115,14 @@

      *         or <code>null</code> if point is not contained within
      *         this DetectorElement or its children.
      */    

-    public IDetectorElement findDetectorElement(Hep3Vector globalPoint);   

+    public IDetectorElement findDetectorElement(Hep3Vector globalPoint);
+    
+    /**
+     * Locate a child detector element by {@link IIdentifier}.
+     * @param  id The <code>IIdentifier</code> of the <code>DetectorElement</code>.
+     * @return    The matching <code>IDetectorElement</code> to the ID.
+     */
+    public IDetectorElementContainer findDetectorElement(IIdentifier id);

     
     /**
      * Get the readout associated with this DetectorElement,

diff -u -r1.7 -r1.8
--- IDetectorElementContainer.java	23 May 2007 00:09:15 -0000	1.7
+++ IDetectorElementContainer.java	25 May 2007 20:16:26 -0000	1.8
@@ -17,26 +17,33 @@

  * @see java.util.ArrayList
  * 
  * @author Jeremy McCormick

- * @version $Id: IDetectorElementContainer.java,v 1.7 2007/05/23 00:09:15 jeremy Exp $

+ * @version $Id: IDetectorElementContainer.java,v 1.8 2007/05/25 20:16:26 jeremy Exp $

  */
 public interface IDetectorElementContainer 
 extends List<IDetectorElement>

-{

+{      

     /**

-     * Get a DetectorElement by name.

+     * Find an {@link IDetectorElement} by class.
+     * @param  klass The class.
+     * @return A <code>List</code> of <code>DetectorElement</code> objects with matching class.
+     */
+    public IDetectorElementContainer find(Class<? extends IDetectorElement> klass);    
+    
+    /**
+     * Find an {@link IDetectorElement} by name.

      * 
      * @param  name The name of the DetectorElement.
      * @return      The DetectorElement matching name or
      *              <code>null</code> if none exists.
      */

-    public IDetectorElement get(String name);

+    public IDetectorElementContainer find(String name);

     
     /**

-     * True if contains a DetectorElement with matching name. 

+     * Find an {@link IDetectorElement} by {@link IIdentifier}.

      * 

-     * @param   name The name of the DetectorElement.
-     * @return       True if contains a DetectorElement with
-     *               matching name; False if it does not.

+     * @param  id The id of the DetectorElement.
+     * @return    The DetectorElement matching id or
+     *            <code>null</code> if none exists.

      */

-    public boolean contains(String name);
-}

+    public IDetectorElementContainer find(IIdentifier id);   
+}

\ No newline at end of file

diff -u -r1.4 -r1.5
--- IDetectorElementStore.java	23 May 2007 00:09:15 -0000	1.4
+++ IDetectorElementStore.java	25 May 2007 20:16:26 -0000	1.5
@@ -1,19 +1,15 @@

 package org.lcsim.detector;
 

-import org.lcsim.detector.identifier.IIdentifier;
-

 /**

- * The {@link IDetectorElementStore} is a registry of 
- * all {@link IDetectorElement}s in the current detector.

+ * The {@link IDetectorElementStore} is an {@link IDetectorElementContainer}
+ * containing all {@link IDetectorElement}s in the current detector.

  * 
  * @see IDetectorElement
  * @see IObjectStore
  * 
  * @author jeremym

- * @version $Id: IDetectorElementStore.java,v 1.4 2007/05/23 00:09:15 jeremy Exp $

+ * @version $Id: IDetectorElementStore.java,v 1.5 2007/05/25 20:16:26 jeremy Exp $

  */
 public interface IDetectorElementStore 
 extends IDetectorElementContainer

-{    
-    public IDetectorElement findDetectorElement(IIdentifier id);
-}

\ No newline at end of file

+{}

\ No newline at end of file

diff -u -r1.1 -r1.2
--- IParametersStore.java	22 May 2007 20:02:03 -0000	1.1
+++ IParametersStore.java	25 May 2007 20:16:26 -0000	1.2
@@ -1,13 +1,18 @@

 package org.lcsim.detector;
 
 /**

- * Access to {@link IParameter} objects for the current detector.

+ * Access to all {@link IParameters} objects for the current detector.

  * 
  * @author Jeremy McCormick

- * @version $Id: IParametersStore.java,v 1.1 2007/05/22 20:02:03 jeremy Exp $

+ * @version $Id: IParametersStore.java,v 1.2 2007/05/25 20:16:26 jeremy Exp $

  */
 public interface IParametersStore 
 extends IObjectStore<IParameters>
 {

-    public IParameters getParameters(String name);

+    /**
+     * Get a set of parameters by name.
+     * @param name The name of the parameter set.
+     * @return     The parameters.
+     */
+    public IParameters get(String name);

 }

\ No newline at end of file

diff -u -r1.2 -r1.3
--- XMLConverter.java	22 May 2007 20:02:04 -0000	1.2
+++ XMLConverter.java	25 May 2007 20:16:26 -0000	1.3
@@ -6,9 +6,7 @@

 /**
  * 
  * A generic interface for converting from JDOM/XML 

- * to runtime objects.  The method {@link #convert(Element)} 
- * will be called for all elements with a name that matchs 
- * {@link #getElementName()}.

+ * to runtime objects.  

  * 
  * The activate method does not return a specific type.  It
  * can create one or more Java objects, but these must be

diff -u -r1.18 -r1.19
--- DetectorConverter.java	22 May 2007 20:02:04 -0000	1.18
+++ DetectorConverter.java	25 May 2007 20:16:26 -0000	1.19
@@ -165,7 +165,7 @@

                     ((DetectorElement)subdet.getDetectorElement()).setIdentifierHelper( new IdentifierHelper( iddict ) );
                     
                     // Set the Parameters.

-                    ((DetectorElement)subdet.getDetectorElement()).setParameters(ParametersStore.getInstance().getParameters(subdet.getName()));

+                    ((DetectorElement)subdet.getDetectorElement()).setParameters(ParametersStore.getInstance().get(subdet.getName()));

                 }
 			}            
 		}		

diff -u -r1.18 -r1.19
--- SiTrackerBarrelConverter.java	23 May 2007 00:09:16 -0000	1.18
+++ SiTrackerBarrelConverter.java	25 May 2007 20:16:26 -0000	1.19
@@ -10,7 +10,6 @@

 
 import org.jdom.DataConversionException;
 import org.jdom.Element;

-import org.lcsim.detector.DetectorElement;

 import org.lcsim.detector.IDetectorElement;
 import org.lcsim.detector.ILogicalVolume;
 import org.lcsim.detector.IPhysicalVolume;

@@ -30,6 +29,7 @@

 import org.lcsim.detector.solids.ISolid;
 import org.lcsim.detector.solids.Tube;
 import org.lcsim.detector.tracker.silicon.ChargeCarrier;

+import org.lcsim.detector.tracker.silicon.DeSiTrackerBarrel;

 import org.lcsim.detector.tracker.silicon.SiSensor;
 import org.lcsim.detector.tracker.silicon.SiStrips;
 import org.lcsim.detector.tracker.silicon.SiTrackerBarrelLayer;

@@ -44,7 +44,7 @@

 {
     public void convert( Subdetector subdet, Detector detector)
     {        

-    	subdet.setDetectorElement( new DeSubdetector( detector, subdet ) );

+    	subdet.setDetectorElement( new DeSiTrackerBarrel( subdet.getName(), detector.getDetectorElement()));

     	
         Map<String, ILogicalVolume> modules = buildModules(subdet);
         

diff -u -r1.5 -r1.6
--- IIdentifiable.java	22 May 2007 20:02:05 -0000	1.5
+++ IIdentifiable.java	25 May 2007 20:16:26 -0000	1.6
@@ -2,11 +2,11 @@

 
 /**
  * A mix-in interface for objects that have an associated {@link IIdentifier},

- * corresponding {@IExpandedIdentifier}, and an {@link IIdentifierHelper}

+ * corresponding {@link IExpandedIdentifier}, and an {@link IIdentifierHelper}

  * for performing pack and unpack operations on these objects.
  *  
  * @author Jeremy McCormick

- * @version $Id: IIdentifiable.java,v 1.5 2007/05/22 20:02:05 jeremy Exp $

+ * @version $Id: IIdentifiable.java,v 1.6 2007/05/25 20:16:26 jeremy Exp $

  */
 public interface IIdentifiable 
 {

diff -u -r1.4 -r1.5
--- IIdentifierField.java	19 May 2007 00:39:51 -0000	1.4
+++ IIdentifierField.java	25 May 2007 20:16:26 -0000	1.5
@@ -6,7 +6,7 @@

  * an ordered collection of these fields.
  *
  * @author Jeremy McCormick

- * @version $Id: IIdentifierField.java,v 1.4 2007/05/19 00:39:51 jeremy Exp $

+ * @version $Id: IIdentifierField.java,v 1.5 2007/05/25 20:16:26 jeremy Exp $

  */
 public interface IIdentifierField
 {

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

     /**
      * Pack a single value of this field into a {@link IIdentifier}.
      * 

-     * @param value
-     * @return

+     * @param value A value to pack into this field.
+     * @return An identifier with the packed value.

      */
     public IIdentifier pack( int value );
     

@@ -93,7 +93,7 @@

      * 
      * @param id The <code>ExpandedIdentifier</code>.
      * @return The field value.

-     * @throw IllegalArgumentException if field index is not valid for the id.

+     * @throws IllegalArgumentException if field index is not valid for the id.

      */
     public int getFieldValue( IExpandedIdentifier id );    
 }

\ No newline at end of file

diff -N DeSiTrackerBarrel.java
--- /dev/null	1 Jan 1970 00:00:00 -0000
+++ DeSiTrackerBarrel.java	25 May 2007 20:16:27 -0000	1.1
@@ -0,0 +1,40 @@

+package org.lcsim.detector.tracker.silicon;
+
+import org.lcsim.detector.DetectorElement;
+import org.lcsim.detector.IDetectorElement;
+import org.lcsim.detector.IDetectorElementContainer;
+import org.lcsim.detector.identifier.IExpandedIdentifier;
+import org.lcsim.detector.identifier.IIdentifier;
+import org.lcsim.detector.identifier.IIdentifierHelper;
+
+/**
+ * A {@link IDetectorElement} for SiTrackerBarrel.
+ *
+ * @author Jeremy McCormick
+ * @version $Id: DeSiTrackerBarrel.java,v 1.1 2007/05/25 20:16:27 jeremy Exp $
+ */
+
+public class DeSiTrackerBarrel
+extends DetectorElement
+{
+    public DeSiTrackerBarrel(String name, IDetectorElement parent)
+    {
+        super(name, parent);
+    }    
+    
+    public IDetectorElementContainer findDetectorElement(IIdentifier id)
+    {        
+        // Get the IdentifierHelper.
+        IIdentifierHelper helper = getIdentifierHelper();
+     
+        // Make an expanded identifier containing only geometric fields.
+        IExpandedIdentifier expId = 
+            helper.unpack(id, 0, helper.getIdentifierDictionary().getFieldIndex("side") - 1);
+
+        // Repack the Identifier.
+        IIdentifier geomId = helper.pack(expId);
+
+        // Use super method once non-geometric fields have been stripped out.
+        return super.findDetectorElement(geomId);
+    }    
+}

\ No newline at end of file

diff -u -r1.8 -r1.9
--- SiSensor.java	23 May 2007 00:09:16 -0000	1.8
+++ SiSensor.java	25 May 2007 20:16:27 -0000	1.9
@@ -513,10 +513,9 @@

     /**
      * Make an {@link IIdentifier} for a given strip number and side number.
      * 

-     * @author Jeremy McCormick
-     * @param stripNumber The strip number, which should be from 1 to nstrips-1.

+     * @param stripNumber The strip number, which should be from 1 to nstrips - 1.

      * @param sideNumber  The side number, which should be 1 or -1.

-     * @return A 64-bit   Identifier for the strip.

+     * @return A 64-bit   A packed id for the strip.

      */
     public IIdentifier makeStripId( int stripNumber, int sideNumber )
     {

diff -u -r1.13 -r1.14
--- SimpleDetectorTest.java	16 May 2007 23:27:38 -0000	1.13
+++ SimpleDetectorTest.java	25 May 2007 20:16:27 -0000	1.14
@@ -300,7 +300,6 @@

 	{
 		DummyDE(IPhysicalVolumePath support)
 		{

-			//super("dummy",null,support,null);

             super("dummy");
             setSupport(support);
 		}

diff -u -r1.10 -r1.11
--- DetectorConverterTest.java	9 May 2007 00:59:59 -0000	1.10
+++ DetectorConverterTest.java	25 May 2007 20:16:27 -0000	1.11
@@ -11,6 +11,7 @@

 import junit.framework.TestCase;
 import junit.framework.TestSuite;
 

+import org.lcsim.detector.DetectorElementContainer;

 import org.lcsim.detector.IDetectorElement;
 import org.lcsim.detector.IGeometryInfo;
 import org.lcsim.detector.IPhysicalVolume;

@@ -73,11 +74,13 @@

         // Check for top-level DEs that should have been built.
         for ( String de : des ) 
         {

+            IDetectorElement search = deDetector.getChildren().find(de).get(0);
+            

             // Check that the DE was created.

-            assertTrue("The expected DetectorElement <" + de + "> is missing!", deDetector.getChildren().get(de) != null);

+            assertTrue("The expected DetectorElement <" + de + "> is missing!", search != null);

-            // Check that the DeDetector is findable from this DE.
-            List<DeDetector> detectorSearch = deDetector.getChildren().get(de).findAncestors(DeDetector.class); 

+            // Check that the DeDetector is findable from this node.
+            List<DeDetector> detectorSearch = search.findAncestors(DeDetector.class);

             assertTrue( detectorSearch.size() == 1);
             assertTrue( detectorSearch.get(0).getName().equals("test_detector"));
         }