added new seeding methods for random generators

this will allow implementing some modern and efficient generators
that require a lots of bits for seeding in the form of complete integer arrays

git-svn-id: https://svn.apache.org/repos/asf/commons/proper/math/trunk@796543 13f79535-47bb-0310-9956-ffa450edef68

src/java/org/apache/commons/math/random/AbstractRandomGenerator.java

@@ -61,6 +61,23 @@ public abstract class AbstractRandomGenerator implements RandomGenerator {
         cachedNormalDeviate = Double.NaN;
     }
 
+    /** {@inheritDoc} */
+    public void setSeed(int seed) {
+        setSeed((long) seed);
+    }
+
+    /** {@inheritDoc} */
+    public void setSeed(int[] seed) {
+        // the following number is the largest prime that fits in 32 bits (it is 2^32 - 5)
+        final long prime = 4294967291l;
+
+        long combined = 0l;
+        for (int s : seed) {
+            combined = combined * prime + s;
+        }
+        setSeed(combined);
+    }
+
     /**
      * Sets the seed of the underyling random number generator using a 
      * <code>long</code> seed.  Sequences of values generated starting with the

src/java/org/apache/commons/math/random/JDKRandomGenerator.java

@@ -26,6 +26,25 @@ import java.util.Random;
  * @version $Revision$ $Date$
  */
 public class JDKRandomGenerator extends Random implements RandomGenerator {
-    /** Serializable version identifier */
+
-    private static final long serialVersionUID = -3561898582944940550L;
+    /** Serializable version identifier. */
+    private static final long serialVersionUID = -7745277476784028798L;
+
+    /** {@inheritDoc} */
+    public void setSeed(int seed) {
+        setSeed((long) seed);
+    }
+
+    /** {@inheritDoc} */
+    public void setSeed(int[] seed) {
+        // the following number is the largest prime that fits in 32 bits (it is 2^32 - 5)
+        final long prime = 4294967291l;
+
+        long combined = 0l;
+        for (int s : seed) {
+            combined = combined * prime + s;
+        }
+        setSeed(combined);
+    }
+
 }

src/java/org/apache/commons/math/random/RandomAdaptor.java

@@ -27,8 +27,8 @@ import java.util.Random;
  */
 public class RandomAdaptor extends Random implements RandomGenerator {
     
-    /** Serializable version identifier */
+    /** Serializable version identifier. */
-    private static final long serialVersionUID = 2570805822599485047L;
+    private static final long serialVersionUID = 2306581345647615033L;
 
     /** Wrapped randomGenerator instance */
     private RandomGenerator randomGenerator = null;
@@ -173,17 +173,26 @@ public class RandomAdaptor extends Random implements RandomGenerator {
         return randomGenerator.nextLong();
     }
 
-    /**
+    /** {@inheritDoc} */
-     * Sets the seed of the underyling random number generator using a 
+    public void setSeed(int seed) {
-     * <code>long</code> seed.  Sequences of values generated starting with the
+        if (randomGenerator != null) {  // required to avoid NPE in constructor
-     * same seeds should be identical.
+            randomGenerator.setSeed(seed);
-     *
+        }
-     * @param seed the seed value
+    }
-     */
+
+    /** {@inheritDoc} */
+    public void setSeed(int[] seed) {
+        if (randomGenerator != null) {  // required to avoid NPE in constructor
+            randomGenerator.setSeed(seed);
+        }
+    }
+
+    /** {@inheritDoc} */
     @Override
     public void setSeed(long seed) {
         if (randomGenerator != null) {  // required to avoid NPE in constructor
             randomGenerator.setSeed(seed);
         }
     }
+
 }

src/java/org/apache/commons/math/random/RandomGenerator.java

@@ -26,11 +26,32 @@ package org.apache.commons.math.random;
  */
 public interface RandomGenerator {
     
+    /**
+     * Sets the seed of the underyling random number generator using an
+     * <code>int</code> seed.
+     * <p>Sequences of values generated starting with the same seeds
+     * should be identical.
+     * </p>
+     * @param seed the seed value
+     */
+    void setSeed(int seed);
+
+    /**
+     * Sets the seed of the underyling random number generator using an
+     * <code>int</code> array seed.
+     * <p>Sequences of values generated starting with the same seeds
+     * should be identical.
+     * </p>
+     * @param seed the seed value
+     */
+    void setSeed(int[] seed);
+    
     /**
      * Sets the seed of the underyling random number generator using a
-     * <code>long</code> seed.  Sequences of values generated starting with the
+     * <code>long</code> seed.
-     * same seeds should be identical.
+     * <p>Sequences of values generated starting with the same seeds
-     *
+     * should be identical.
+     * </p>
      * @param seed the seed value
      */
     void setSeed(long seed);

src/test/org/apache/commons/math/random/RandomAdaptorTest.java

@@ -98,7 +98,14 @@ public class RandomAdaptorTest extends RandomDataTest {
             return 0;
         }
 
+        public void setSeed(int seed) {
+        }
+        
+        public void setSeed(int[] seed) {
+        }
+
         public void setSeed(long seed) {
         }
+
     }
 }