Applied patch from Tomasz Skutnik which allows a Random object to be passed

in. This means that method calls to RandomStringUtils can be predictable.

Submitted by:	Tomasz Skutnik <Tomasz.Skutnik@e-point.pl>


git-svn-id: https://svn.apache.org/repos/asf/jakarta/commons/proper/lang/trunk@137238 13f79535-47bb-0310-9956-ffa450edef68

src/java/org/apache/commons/lang/RandomStringUtils.java

@@ -63,7 +63,7 @@ import java.util.Random;
  * @author <a href="mailto:steven@caswell.name">Steven Caswell</a>
  * @author Stephen Colebourne
  * @since 1.0
- * @version $Id: RandomStringUtils.java,v 1.7 2002/12/23 00:32:24 scolebourne Exp $
+ * @version $Id: RandomStringUtils.java,v 1.8 2003/02/02 03:46:13 bayard Exp $
  */
 public class RandomStringUtils {
 
@@ -191,18 +191,16 @@ public class RandomStringUtils {
     public static String random(int count, int start, int end, boolean letters, boolean numbers) {
         return random(count, start, end, letters, numbers, null);
     }
-    
+
     /**
-     * <p>Creates a random string based on a variety of options.</p>
+     * <p>Creates a random string based on a variety of options, using
+     * default source of randomness.</p>
      *
-	 * <p>If start and end are both <code>0</code>, start and end are set
-     * to <code>' '</code> and <code>'z'</code>, the ASCII printable
-     * characters, will be used, unless letters and numbers are both
-	 * <code>false</code>, in which case, start and end are set to
-     * <code>0</code> and <code>Integer.MAX_VALUE</code>.
-     *
-	 * <p>If set is not <code>null</code>, characters between start and
-     * end are chosen.</p>
+     * This method has exactly the same semantics as {@link
+     * #random(int,int,int,boolean,boolean,char[],Random)}, but
+     * instead of depending on internal source of randomness ({@link
+     * #RANDOM}) it uses externally supplied instance of {@link
+     * Random} class.
      *
      * @param count length of random string to create
      * @param start position in set of chars to start at
@@ -216,6 +214,40 @@ public class RandomStringUtils {
      *  <code>(end - start) + 1</code> characters in the set array.
      */
     public static String random(int count, int start, int end, boolean letters, boolean numbers, char[] set) {
+        return random(count,start,end,letters,numbers,set,RANDOM);
+    }
+
+    /**
+     * <p>Creates a random string based on a variety of options, using
+     * supplied source of randomness.</p>
+     *
+	 * <p>If start and end are both <code>0</code>, start and end are set
+     * to <code>' '</code> and <code>'z'</code>, the ASCII printable
+     * characters, will be used, unless letters and numbers are both
+	 * <code>false</code>, in which case, start and end are set to
+     * <code>0</code> and <code>Integer.MAX_VALUE</code>.
+     *
+	 * <p>If set is not <code>null</code>, characters between start and
+     * end are chosen.</p>
+     *
+     * <p>As a source of randomness is used supplied {@link Random}
+     * instance. This makes method behave predictively, and allows
+     * usage of <code>RandomStringUtils</code> in situations that need
+     * repetitive behaviour.</p>
+     *
+     * @param count length of random string to create
+     * @param start position in set of chars to start at
+     * @param end position in set of chars to end before
+     * @param letters only allow letters?
+     * @param numbers only allow numbers?
+     * @param set set of chars to choose randoms from. If <code>null</code>,
+     *  then it will use the set of all chars.
+     * @param random source of randomness.
+     * @return the random string
+     * @throws ArrayIndexOutOfBoundsException if there are not
+     *  <code>(end - start) + 1</code> characters in the set array.
+     */
+    public static String random(int count, int start, int end, boolean letters, boolean numbers, char[] set, Random random) {
         if( (start == 0) && (end == 0) ) {
             end = (int)'z';
             start = (int)' ';
@@ -231,9 +263,9 @@ public class RandomStringUtils {
         while(count-- != 0) {
             char ch;
             if(set == null) {
-                ch = (char)(RANDOM.nextInt(gap) + start);
+                ch = (char)(random.nextInt(gap) + start);
             } else {
-                ch = set[RANDOM.nextInt(gap) + start];
+                ch = set[random.nextInt(gap) + start];
             }
             if( (letters && numbers && Character.isLetterOrDigit(ch)) ||
                 (letters && Character.isLetter(ch)) ||

src/test/org/apache/commons/lang/RandomStringUtilsTest.java

@@ -54,6 +54,8 @@ package org.apache.commons.lang;
  * <http://www.apache.org/>.
  */
 
+import java.util.Random;
+
 import junit.framework.*;
 import junit.textui.TestRunner;
 /**
@@ -61,7 +63,7 @@ import junit.textui.TestRunner;
  *
  * @author <a href="mailto:steven@caswell.name">Steven Caswell</a>
  * @author <a href="mailto:ridesmet@users.sourceforge.net">Ringo De Smet</a>
- * @version $Id: RandomStringUtilsTest.java,v 1.2 2002/10/08 19:01:39 sullis Exp $
+ * @version $Id: RandomStringUtilsTest.java,v 1.3 2003/02/02 03:46:13 bayard Exp $
  */
 public class RandomStringUtilsTest extends junit.framework.TestCase {
     /**
@@ -148,6 +150,11 @@ public class RandomStringUtilsTest extends junit.framework.TestCase {
         }
         r2 = RandomStringUtils.random(50, set);
         assertTrue("!r1.equals(r2)", !r1.equals(r2));
+
+        long seed = System.currentTimeMillis();
+        r1 = RandomStringUtils.random(50,0,0,true,true,null,new Random(seed));
+        r2 = RandomStringUtils.random(50,0,0,true,true,null,new Random(seed));
+        assertEquals("r1.equals(r2)", r1, r2);
     }
 
     public static void main(String args[]) {