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diff --git a/src/demos/util/SystemTime.java b/src/demos/util/SystemTime.java
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+/*
+ * Copyright (c) 2003 Sun Microsystems, Inc. All Rights Reserved.
+ * 
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ * 
+ * - Redistribution of source code must retain the above copyright
+ *   notice, this list of conditions and the following disclaimer.
+ * 
+ * - Redistribution in binary form must reproduce the above copyright
+ *   notice, this list of conditions and the following disclaimer in the
+ *   documentation and/or other materials provided with the distribution.
+ * 
+ * Neither the name of Sun Microsystems, Inc. or the names of
+ * contributors may be used to endorse or promote products derived from
+ * this software without specific prior written permission.
+ * 
+ * This software is provided "AS IS," without a warranty of any kind. ALL
+ * EXPRESS OR IMPLIED CONDITIONS, REPRESENTATIONS AND WARRANTIES,
+ * INCLUDING ANY IMPLIED WARRANTY OF MERCHANTABILITY, FITNESS FOR A
+ * PARTICULAR PURPOSE OR NON-INFRINGEMENT, ARE HEREBY EXCLUDED. SUN
+ * MICROSYSTEMS, INC. ("SUN") AND ITS LICENSORS SHALL NOT BE LIABLE FOR
+ * ANY DAMAGES SUFFERED BY LICENSEE AS A RESULT OF USING, MODIFYING OR
+ * DISTRIBUTING THIS SOFTWARE OR ITS DERIVATIVES. IN NO EVENT WILL SUN OR
+ * ITS LICENSORS BE LIABLE FOR ANY LOST REVENUE, PROFIT OR DATA, OR FOR
+ * DIRECT, INDIRECT, SPECIAL, CONSEQUENTIAL, INCIDENTAL OR PUNITIVE
+ * DAMAGES, HOWEVER CAUSED AND REGARDLESS OF THE THEORY OF LIABILITY,
+ * ARISING OUT OF THE USE OF OR INABILITY TO USE THIS SOFTWARE, EVEN IF
+ * SUN HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES.
+ * 
+ * You acknowledge that this software is not designed or intended for use
+ * in the design, construction, operation or maintenance of any nuclear
+ * facility.
+ * 
+ * Sun gratefully acknowledges that this software was originally authored
+ * and developed by Kenneth Bradley Russell and Christopher John Kline.
+ */
+
+package demos.util;
+
+/** Implementation of {@link demos.util.Time} interface based
+    on {@link java.lang.System.currentTimeMillis}. Performs smoothing
+    internally to avoid effects of poor granularity of
+    currentTimeMillis on Windows platform in particular. */
+
+public class SystemTime implements Time {
+  private static final int DEFAULT_NUM_SMOOTHING_SAMPLES = 10;
+  private long[] samples = new long[DEFAULT_NUM_SMOOTHING_SAMPLES];
+  private int   numSmoothingSamples;
+  private int   curSmoothingSample; // Index of current sample to be replaced
+  private long baseTime = System.currentTimeMillis();
+  private boolean hasCurTime;
+  private double curTime;
+  private double deltaT;
+
+  /** Sets number of smoothing samples. Defaults to 10. Note that
+      there may be a discontinuity in the reported time after a call
+      to this method. */
+  public void setNumSmoothingSamples(int num) {
+    samples = new long[num];
+    numSmoothingSamples = 0;
+    curSmoothingSample = 0;
+    hasCurTime = false;
+  }
+
+  /** Returns number of smoothing samples; default is 10. */
+  public int getNumSmoothingSamples() {
+    return samples.length;
+  }
+
+  /** Rebases this timer. After very long periods of time the
+      resolution of this timer may decrease; the application can call
+      this to restore higher resolution. Note that there may be a
+      discontinuity in the reported time after a call to this
+      method. */
+  public void rebase() {
+    baseTime = System.currentTimeMillis();
+    setNumSmoothingSamples(samples.length);
+  }
+
+  public void update() {
+    long tmpTime = System.currentTimeMillis();
+    long diffSinceBase = tmpTime - baseTime;
+    samples[curSmoothingSample] = diffSinceBase;
+    curSmoothingSample = (curSmoothingSample + 1) % samples.length;
+    numSmoothingSamples = Math.min(1 + numSmoothingSamples, samples.length);
+    // Average of samples is current time
+    double newCurTime = 0.0;
+    for (int i = 0; i < numSmoothingSamples; i++) {
+      newCurTime += samples[i];
+    }
+    newCurTime /= (1000.0f * numSmoothingSamples);
+    double lastTime = curTime;
+    if (!hasCurTime) {
+      lastTime = newCurTime;
+      hasCurTime = true;
+    }
+    deltaT = newCurTime - lastTime;
+    curTime = newCurTime;
+  }
+
+  public double time() {
+    return curTime;
+  }
+
+  public double deltaT() {
+    return deltaT;
+  }
+}