--- java/trunk/conditions/src/test/java/org/hps/conditions/ecal/PhysicalToGainTest.java	                        (rev 0)
+++ java/trunk/conditions/src/test/java/org/hps/conditions/ecal/PhysicalToGainTest.java	2014-04-08 20:17:15 UTC (rev 468)
@@ -0,0 +1,115 @@

+package org.hps.conditions.ecal;
+
+import java.io.File;
+import java.net.URL;
+import java.util.List;
+
+import junit.framework.TestCase;
+
+import org.hps.conditions.ConditionsDriver;
+import org.hps.conditions.TableConstants;
+import org.hps.conditions.ecal.EcalChannel.EcalChannelCollection;
+import org.hps.conditions.ecal.EcalChannel.GeometryId;
+import org.lcsim.conditions.ConditionsManager;
+import org.lcsim.detector.identifier.IIdentifier;
+import org.lcsim.detector.identifier.IIdentifierHelper;
+import org.lcsim.detector.identifier.Identifier;
+import org.lcsim.event.EventHeader;
+import org.lcsim.event.RawCalorimeterHit;
+import org.lcsim.geometry.Detector;
+import org.lcsim.util.Driver;
+import org.lcsim.util.cache.FileCache;
+import org.lcsim.util.loop.LCSimLoop;
+
+/**
+ * This is a simple example of how to retrieve the gain and noise by physical ID (X,Y) in the ECAL.
+ * @author Jeremy McCormick <[log in to unmask]>
+ */
+public class PhysicalToGainTest extends TestCase {
+
+    // This test file has a few events from each of the "good runs" of the 2012 Test Run. 
+    private static final String TEST_FILE_URL = "http://www.lcsim.org/test/hps/conditions_test.slcio";
+                    
+    // Run the test.
+    public void test() throws Exception {
+
+        // Cache a data file from the www.
+        FileCache cache = new FileCache();
+        File testFile = cache.getCachedFile(new URL(TEST_FILE_URL));
+        
+        // Create the record loop.        
+        LCSimLoop loop = new LCSimLoop();
+                        
+        // Configure the loop.
+        loop.setLCIORecordSource(testFile);
+        loop.add(new ConditionsDriver());
+        loop.add(new PhysicalToGainDriver());
+                
+        // Run a few events.
+        loop.loop(1, null);        
+    }   
+    
+    static class PhysicalToGainDriver extends Driver {
+        
+        static final String collectionName = "EcalReadoutHits";
+        EcalConditions ecalConditions = null;
+        IIdentifierHelper helper = null;
+        EcalChannelCollection channels = null;    
+        
+        public void detectorChanged(Detector detector) {
+            
+            // ECAL combined conditions object.
+            ecalConditions = ConditionsManager.defaultInstance()
+                    .getCachedConditions(EcalConditions.class, TableConstants.ECAL_CONDITIONS).getCachedData();
+            
+            // List of channels.
+            channels = ecalConditions.getChannelMap();
+            
+            // ID helper.
+            helper = detector.getSubdetector("Ecal").getDetectorElement().getIdentifierHelper();
+        }
+        
+        public void process(EventHeader event) {
+            if (event.hasCollection(RawCalorimeterHit.class, collectionName)) {
+                
+                // Get ECAL raw hits from event.
+                List<RawCalorimeterHit> hits = event.get(RawCalorimeterHit.class, collectionName);
+                for (RawCalorimeterHit hit : hits) {    
+                                        
+                    // Get the ECAL channel.
+                    EcalChannel channel = findChannel(hit);
+                    
+                    // Get the channel data.
+                    EcalChannelConstants channelData = ecalConditions.getChannelConstants(channel);
+                    
+                    // Get gain and noise.
+                    double gain = channelData.getGain().getGain();
+                    double noise = channelData.getCalibration().getNoise();
+                    
+                    // Debug print the channel data.
+                    System.out.println("channel " + channel.getX() + "," + channel.getY() 
+                            + " has gain " + channelData.getGain().getGain() 
+                            + " and noise " + channelData.getCalibration().getNoise());
+                }
+            }
+        }
+
+        // Convert physical ID to gain value.
+        private EcalChannel findChannel(RawCalorimeterHit hit) {
+            // Make an ID object from raw hit ID.
+            IIdentifier id = new Identifier(hit.getCellID());
+            
+            // Get physical field values.
+            int x = helper.getValue(id, "ix");
+            int y = helper.getValue(id, "iy");
+            
+            // Create an ID to search for in channel collection.
+            GeometryId geometryId = new GeometryId();
+            geometryId.x = x;
+            geometryId.y = y;
+            
+            // Find the ECAL channel.
+            return channels.findChannel(geometryId);
+        }
+    }
+}