1 /***
2 * Redistribution and use in source and binary forms, with or without
3 * modification, are permitted provided that the following conditions are
4 * met :
5 *
6 * . Redistributions of source code must retain the above copyright
7 * notice, this list of conditions and the following disclaimer.
8 *
9 * . Redistributions in binary form must reproduce the above copyright
10 * notice, this list of conditions and the following disclaimer in the
11 * documentation and/or other materials provided with the distribution.
12 *
13 * . The name of the author may not be used to endorse or promote products
14 * derived from this software without specific prior written permission.
15 *
16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
17 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
18 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
19 * DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT,
20 * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
21 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
22 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
24 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
25 * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
26 * POSSIBILITY OF SUCH DAMAGE.
27 *
28 * $Id: RandomIterator.java,v 1.3 2005/08/26 18:09:36 mat007 Exp $
29 */
30
31 package jtge.util.random;
32
33 import java.util.Iterator;
34 import java.util.Vector;
35
36 /***
37 * Wraps an iterator to provide randomization of its elements.
38 *
39 * @author Mathieu Champlon
40 * @version $Revision: 1.3 $ $Date: 2005/08/26 18:09:36 $
41 */
42 public class RandomIterator implements Iterator
43 {
44 /***
45 * The randomized iterator.
46 */
47 private final Iterator iterator;
48
49 /***
50 * Create a random iterator over a list.
51 *
52 * @param random the random number generator
53 * @param iterator the data to randomize
54 */
55 public RandomIterator( final IRandom random, final Iterator iterator )
56 {
57 if( random == null )
58 throw new IllegalArgumentException( "argument 'random' is null" );
59 final Vector vector = new Vector();
60 if( iterator != null )
61 while( iterator.hasNext() )
62 vector.insertElementAt( iterator.next(), random.nextInt( vector.size() + 1 ) );
63 this.iterator = vector.iterator();
64 }
65
66 /***
67 * {@inheritDoc}
68 */
69 public final void remove()
70 {
71 throw new UnsupportedOperationException();
72 }
73
74 /***
75 * {@inheritDoc}
76 */
77 public final boolean hasNext()
78 {
79 return iterator.hasNext();
80 }
81
82 /***
83 * {@inheritDoc}
84 */
85 public final Object next()
86 {
87 return iterator.next();
88 }
89 }