Author: psteitz
Date: Fri Nov 4 16:20:05 2011
New Revision: 1197626
URL: http://svn.apache.org/viewvc?rev=1197626&view=rev
Log:
Changed default non-secure generator to Well19937c and changed default seeds to
add system identity haschode to timestamp. JIRA: MATH-701.
Modified:
commons/proper/math/trunk/src/main/java/org/apache/commons/math/random/RandomDataImpl.java
Modified:
commons/proper/math/trunk/src/main/java/org/apache/commons/math/random/RandomDataImpl.java
URL:
http://svn.apache.org/viewvc/commons/proper/math/trunk/src/main/java/org/apache/commons/math/random/RandomDataImpl.java?rev=1197626&r1=1197625&r2=1197626&view=diff
==============================================================================
---
commons/proper/math/trunk/src/main/java/org/apache/commons/math/random/RandomDataImpl.java
(original)
+++
commons/proper/math/trunk/src/main/java/org/apache/commons/math/random/RandomDataImpl.java
Fri Nov 4 16:20:05 2011
@@ -49,7 +49,7 @@ import org.apache.commons.math.util.Resi
* instance to generate non-secure data and a {@link
java.security.SecureRandom}
* instance to provide data for the <code>nextSecureXxx</code> methods. If no
* <code>RandomGenerator</code> is provided in the constructor, the default is
- * to use a generator based on {@link java.util.Random}. To plug in a different
+ * to use a {@link Well19937c} generator. To plug in a different
* implementation, either implement <code>RandomGenerator</code> directly or
* extend {@link AbstractRandomGenerator}.
* <p>
@@ -81,10 +81,10 @@ import org.apache.commons.math.util.Resi
* When a new <code>RandomDataImpl</code> is created, the underlying random
* number generators are <strong>not</strong> initialized. If you do not
* explicitly seed the default non-secure generator, it is seeded with the
- * current time in milliseconds on first use. The same holds for the secure
- * generator. If you provide a <code>RandomGenerator</code> to the constructor,
- * however, this generator is not reseeded by the constructor nor is it
reseeded
- * on first use.</li>
+ * current time in milliseconds plus the system identity hash code on first
use.
+ * The same holds for the secure generator. If you provide a
<code>RandomGenerator</code>
+ * to the constructor, however, this generator is not reseeded by the
constructor
+ * nor is it reseeded on first use.</li>
* <li>
* The <code>reSeed</code> and <code>reSeedSecure</code> methods delegate to
the
* corresponding methods on the underlying <code>RandomGenerator</code> and
@@ -827,7 +827,8 @@ public class RandomDataImpl implements R
/**
* Returns the RandomGenerator used to generate non-secure random data.
* <p>
- * Creates and initializes a default generator if null.
+ * Creates and initializes a default generator if null. Uses a {@link
Well19937c}
+ * generator with {@code System.currentTimeMillis() + hashCode()} as the
default seed.
* </p>
*
* @return the Random used to generate random data
@@ -835,8 +836,7 @@ public class RandomDataImpl implements R
*/
private RandomGenerator getRan() {
if (rand == null) {
- rand = new JDKRandomGenerator();
- rand.setSeed(System.currentTimeMillis());
+ rand = new Well19937c(System.currentTimeMillis() + hashCode());
}
return rand;
}
@@ -844,7 +844,8 @@ public class RandomDataImpl implements R
/**
* Returns the SecureRandom used to generate secure random data.
* <p>
- * Creates and initializes if null.
+ * Creates and initializes if null. Uses
+ * {@code System.currentTimeMillis() + hashCode()} as the default seed.
* </p>
*
* @return the SecureRandom used to generate secure random data
@@ -852,7 +853,7 @@ public class RandomDataImpl implements R
private SecureRandom getSecRan() {
if (secRand == null) {
secRand = new SecureRandom();
- secRand.setSeed(System.currentTimeMillis());
+ secRand.setSeed(System.currentTimeMillis() + hashCode());
}
return secRand;
}
