diff -N DetectorService.java
--- /dev/null	1 Jan 1970 00:00:00 -0000
+++ DetectorService.java	21 Sep 2007 01:42:12 -0000	1.1
@@ -0,0 +1,62 @@

+package org.lcsim.services;
+
+import org.lcsim.conditions.DetectorLocator;
+import org.lcsim.detector.IDetectorElement;
+import org.lcsim.geometry.Detector;
+
+/**
+ * A service for locating a {@link org.lcsim.detector.IDetectorElement} given a 
+ * fully qualified path string.
+ * 
+ * @author jeremym
+ * @version $Id: DetectorService.java,v 1.1 2007/09/21 01:42:12 jeremy Exp $
+ */
+public class DetectorService 
+{
+	/**
+	 * Find an {@link org.lcsim.detector.IDetectorElement} given a fully qualified
+	 * path string.  
+	 * 
+	 * The path string should in the format "/FullDetectorName/Subsys/Subcomponent",
+	 * for instance, "/sid01/VertexBarrel/VertexBarrel_layer0".
+	 * 
+	 * This method uses the conditions system to locate the full detector 
+	 * from the first portion of the path.  This has the side effect of setting 
+	 * the "current" detector and triggering the conditions listeners
+	 * of the default ConditionsManager that the detector has changed.  For this
+	 * reason, it is not advisable to call this method in the event loop, as there
+	 * is quite a lot of overhead to looking up and building the full detector
+	 * from scratch.
+	 * 
+	 * @param pathString A fully qualified path string including the name of the detector.
+	 * @return A {@link org.lcsim.detector.IDetectorElement} matching the <code>pathString</code>.
+	 */
+	public IDetectorElement getDetectorElement(String pathString)
+	{
+		// Strip out leading '/' char.
+		if (pathString.charAt(0) == '/')
+			pathString = pathString.substring(1);
+				
+		// Make a path to lookup.
+		String path[] = pathString.split("/");
+						
+		// Path cannot be empty.
+		if (path.length == 0)
+			throw new IllegalArgumentException("Path string is empty!");
+				
+		// Lookup the detector by name.
+		String detectorName = path[0];		
+		Detector detector = DetectorLocator.findDetector(detectorName);		
+		IDetectorElement de = detector.getDetectorElement();
+		
+		// Find the detector subcomponent if there is one in the path.
+		if (path.length > 1)
+		{
+			String subpath[] = new String[path.length - 1];
+			System.arraycopy(path, 1, subpath, 0, path.length - 1);
+			de = de.findDetectorElement(subpath);
+		}
+
+		return de;
+	}
+}

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