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Semester 1/Programming 1/Java/examples/projects/chapter12/foxes-and-rabbits-v1/Randomizer.java

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+import java.util.Random;
+
+/**
+ * Provide control over the randomization of the simulation. By using the shared, fixed-seed 
+ * randomizer, repeated runs will perform exactly the same (which helps with testing). Set 
+ * 'useShared' to false to get different random behaviour every time.
+ * 
+ * @author David J. Barnes and Michael Kölling
+ * @version 2016.02.29
+ */
+public class Randomizer
+{
+    // The default seed for control of randomization.
+    private static final int SEED = 1111;
+    // A shared Random object, if required.
+    private static final Random rand = new Random(SEED);
+    // Determine whether a shared random generator is to be provided.
+    private static final boolean useShared = true;
+
+    /**
+     * Constructor for objects of class Randomizer
+     */
+    public Randomizer()
+    {
+    }
+
+    /**
+     * Provide a random generator.
+     * @return A random object.
+     */
+    public static Random getRandom()
+    {
+        if(useShared) {
+            return rand;
+        }
+        else {
+            return new Random();
+        }
+    }
+    
+    /**
+     * Reset the randomization.
+     * This will have no effect if randomization is not through a shared Random generator.
+     */
+    public static void reset()
+    {
+        if(useShared) {
+            rand.setSeed(SEED);
+        }
+    }
+}