lcsim/src/org/lcsim/util

diff -N Timer.java
--- /dev/null	1 Jan 1970 00:00:00 -0000
+++ Timer.java	27 May 2009 18:06:45 -0000	1.1
@@ -0,0 +1,61 @@

+/*
+ * Timer class
+ */
+package org.lcsim.util;
+
+import org.lcsim.event.EventHeader;
+import org.lcsim.util.aida.AIDA;
+
+/**
+ * Driver to perform timing measurements on a driver.  For each driver that you
+ * want to measure the timing of, instantiate a new instance of Timer with a
+ * unique name.  Then add this driver both before and after the driver to be
+ * timed.  An aida plot will be created showing the distribution of driver
+ * processing times.
+ *
+ * No correction is made for the time taken up in the timing measurement itself.
+ * To estimate this, one could instantiate a copy of Timer and call it twice
+ * in succession.
+ *
+ * @author Richard Partridge
+ */
+public class Timer extends Driver {
+
+    private String _message;
+    private int _last_hash;
+    private long _start = 0;
+    private AIDA _aida;
+
+    /**
+     * Timer constructor.  The message string is passed to aida as the title
+     * for a cloud, so it should be unique for each timing measurement.
+     *
+     * @param message title for aida cloud plot
+     */
+    public Timer(String message) {
+        _message = message;
+        _aida = AIDA.defaultInstance();
+    }
+
+    /**
+     * Timer driver process method.  If this is the first call for a given
+     * event, it saves the start time.  For subsequent calls, it plots the
+     * time difference between the current time and the saved start time.
+     *
+     * @param event event header
+     */
+    @Override
+    public void process(EventHeader event) {
+        super.process(event);
+        int hash = event.hashCode();
+        long time = System.currentTimeMillis();
+        if (hash == _last_hash) {
+            double duration = (time - _start) / 1000.;
+            _aida.cloud1D(_message).fill(duration);
+        } else {
+            _start = time;
+        }
+        _last_hash = hash;
+    }
+
+}