diff -N FilterMCBunches.java
--- /dev/null	1 Jan 1970 00:00:00 -0000
+++ FilterMCBunches.java	21 Jun 2012 18:53:57 -0000	1.1
@@ -0,0 +1,159 @@

+package org.lcsim.hps.users.meeg;
+
+import java.io.*;
+
+import java.util.List;
+import org.apache.commons.cli.CommandLine;
+import org.apache.commons.cli.CommandLineParser;
+import org.apache.commons.cli.HelpFormatter;
+import org.apache.commons.cli.Option;
+import org.apache.commons.cli.Options;
+import org.apache.commons.cli.ParseException;
+import org.apache.commons.cli.PosixParser;
+import org.lcsim.event.EventHeader;
+import org.lcsim.event.SimCalorimeterHit;
+import org.lcsim.event.SimTrackerHit;
+import org.lcsim.event.base.BaseLCSimEvent;
+import org.lcsim.util.lcio.LCIOReader;
+import org.lcsim.util.lcio.LCIOWriter;
+
+/**
+ * Selects LCIO events passing a cut; spaces out these events with blank events.
+ * Intended use is to clean up a photon-run MC file before running trigger and readout sim.
+ *
+ * @author Sho Uemura <[log in to unmask]>
+ * @version $Id: FilterMCBunches.java,v 1.1 2012/06/21 18:53:57 meeg Exp $
+ */
+public class FilterMCBunches {
+
+    /**
+     * Defines command line options for this program.
+     *
+     * @return The command line options.
+     */
+    private static Options createCommandLineOptions() {
+        Options options = new Options();
+
+        options.addOption(new Option("e", true, "Interval between non-empty events"));
+        options.addOption(new Option("n", true, "Number of events to read"));
+
+        return options;
+    }
+
+    /**
+     * This method will execute the EVIO to LCIO conversion and perform an
+     * intermediate LCSim job. Then the resultant LCIO events will be written to
+     * disk.
+     *
+     * @param args The command line arguments.
+     */
+    public static void main(String[] args) {
+        // Set up command line parsing.
+        Options options = createCommandLineOptions();
+        if (args.length == 0) {
+            System.out.println("FilterMCBunches <input file> <output file>");
+            HelpFormatter help = new HelpFormatter();
+            help.printHelp(" ", options);
+            System.exit(1);
+        }
+        CommandLineParser parser = new PosixParser();
+
+        // Parse command line arguments.
+        CommandLine cl = null;
+        try {
+            cl = parser.parse(options, args);
+        } catch (ParseException e) {
+            throw new RuntimeException("Problem parsing command line options.", e);
+        }
+
+        String[] parsedArgs = cl.getArgs();
+        String inFileName = parsedArgs[0];
+        String outFileName = parsedArgs[1];
+        LCIOReader reader = null;
+        try {
+            reader = new LCIOReader(new File(inFileName));
+        } catch (IOException e) {
+            throw new RuntimeException(e);
+        }
+
+        LCIOWriter writer = null;
+        try {
+            writer = new LCIOWriter(new File(outFileName));
+        } catch (IOException e) {
+            throw new RuntimeException(e);
+        }
+
+        int nEmpty = 0;
+        if (cl.hasOption("e")) {
+            nEmpty = Integer.valueOf(cl.getOptionValue("e"));
+        }
+
+        int nEvents = -1;
+        if (cl.hasOption("n")) {
+            nEvents = Integer.valueOf(cl.getOptionValue("n"));
+        }
+        int readEvents = 0;
+        int writtenEvents = 0;
+
+        String detectorName = null;
+        while (nEvents == -1 || readEvents < nEvents) {
+            EventHeader event;
+            try {
+                event = reader.read();
+            } catch (IOException e) {
+                break;
+            }
+            readEvents++;
+
+            if (detectorName == null) {
+                detectorName = event.getDetectorName();
+            }
+
+            if (goodEvent(event)) {
+                writtenEvents++;
+                try {
+                    writer.write(event);
+                } catch (IOException e) {
+                    break;
+                }
+
+                for (int i = 1; i < nEmpty; i++) {
+                    event = new BaseLCSimEvent(0, 0, detectorName);
+                    try {
+                        writer.write(event);
+                    } catch (IOException e) {
+                        break;
+                    }
+                }
+            }
+        }
+
+        System.out.format("Read %d events, wrote %d of them\n", readEvents, writtenEvents);
+        try {
+            reader.close();
+            writer.close();
+        } catch (IOException e) {
+            throw new RuntimeException(e);
+        }
+    }
+
+    private static boolean goodEvent(EventHeader event) {
+        List<SimCalorimeterHit> ecalHits = event.getSimCalorimeterHits("EcalHits");
+        List<SimTrackerHit> trackerHits = event.getSimTrackerHits("TrackerHits");
+
+        double maxE = 0;
+        double totalE = 0;
+        for (SimCalorimeterHit hit : ecalHits) {
+            totalE += hit.getRawEnergy();
+            if (hit.getRawEnergy() > maxE) {
+                maxE = hit.getRawEnergy();
+            }
+        }
+
+//        System.out.format("%d SimCalorimeterHits, %d SimTrackerHits, maxE %f, totalE %f\n", ecalHits.size(), trackerHits.size(), maxE, totalE);
+
+
+//        return (ecalHits.size() + trackerHits.size() != 0);
+        return (totalE>0.01);
+    }
+}

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