--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/demo/share/jfc/SwingSet2/Permuter.java	Fri Mar 23 13:43:39 2018 -0700
@@ -0,0 +1,110 @@
+/*
+ *
+ * Copyright (c) 2007, Oracle and/or its affiliates. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ *   - Redistributions of source code must retain the above copyright
+ *     notice, this list of conditions and the following disclaimer.
+ *
+ *   - Redistributions 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 Oracle nor the names of its
+ *     contributors may be used to endorse or promote products derived
+ *     from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
+ * IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
+ * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+ * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE COPYRIGHT OWNER OR
+ * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+ * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
+ * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
+ * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
+ * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+
+
+import java.util.Random;
+
+/**
+ * An object that implements a cheesy pseudorandom permutation of the integers
+ * from zero to some user-specified value. (The permutation is a linear
+ * function.)
+ *
+ * @author Josh Bloch
+ */
+class Permuter {
+    /**
+     * The size of the permutation.
+     */
+    private int modulus;
+
+    /**
+     * Nonnegative integer less than n that is relatively prime to m.
+     */
+    private int multiplier;
+
+    /**
+     * Pseudorandom nonnegative integer less than n.
+     */
+    private int addend = 22;
+
+    public Permuter(int n) {
+        if (n<0) {
+            throw new IllegalArgumentException();
+        }
+        modulus = n;
+        if (n==1) {
+            return;
+        }
+
+        // Initialize the multiplier and offset
+        multiplier = (int) Math.sqrt(n);
+        while (gcd(multiplier, n) != 1) {
+            if (++multiplier == n) {
+                multiplier = 1;
+            }
+        }
+    }
+
+    /**
+     * Returns the integer to which this permuter maps the specified integer.
+     * The specified integer must be between 0 and n-1, and the returned
+     * integer will be as well.
+     */
+    public int map(int i) {
+        return (multiplier * i + addend) % modulus;
+    }
+
+    /**
+     * Calculate GCD of a and b, which are assumed to be non-negative.
+     */
+    private static int gcd(int a, int b) {
+        while(b != 0) {
+            int tmp = a % b;
+            a = b;
+            b = tmp;
+        }
+        return a;
+    }
+
+    /**
+     * Simple test.  Takes modulus on command line and prints out permutation.
+     */
+    public static void main(String[] args) {
+        int modulus = Integer.parseInt(args[0]);
+        Permuter p = new Permuter(modulus);
+        for (int i=0; i<modulus; i++) {
+            System.out.print(p.map(i)+" ");
+        }
+        System.out.println();
+    }
+}