1
22
23 package com.liferay.portal.kernel.util;
24
25 import java.util.Iterator;
26 import java.util.LinkedHashSet;
27 import java.util.List;
28 import java.util.Random;
29 import java.util.Set;
30
31
37 public class Randomizer extends Random {
38
39 public static Randomizer getInstance() {
40 return _instance;
41 }
42
43 public Randomizer() {
44 super();
45 }
46
47 public Randomizer(long seed) {
48 super(seed);
49 }
50
51 public int[] nextInt(int n, int size) {
52 if (size > n) {
53 size = n;
54 }
55
56 Set set = new LinkedHashSet();
57
58 for (int i = 0; i < size; i++) {
59 while (true) {
60 Integer value = new Integer(nextInt(n));
61
62 if (!set.contains(value)) {
63 set.add(value);
64
65 break;
66 }
67 }
68 }
69
70 int[] array = new int[set.size()];
71
72 Iterator itr = set.iterator();
73
74 for (int i = 0; i < array.length; i++) {
75 array[i] = ((Integer)itr.next()).intValue();
76 }
77
78 return array;
79 }
80
81 public void randomize(char array[]) {
82 int length = array.length;
83
84 for(int i = 0; i < length - 1; i++) {
85 int x = nextInt(length);
86 char y = array[i];
87
88 array[i] = array[i + x];
89 array[i + x] = y;
90
91 length--;
92 }
93 }
94
95 public void randomize(int array[]) {
96 int length = array.length;
97
98 for(int i = 0; i < length - 1; i++) {
99 int x = nextInt(length);
100 int y = array[i];
101
102 array[i] = array[i + x];
103 array[i + x] = y;
104
105 length--;
106 }
107 }
108
109 public void randomize(List list) {
110 int size = list.size();
111
112 for(int i = 0; i <= size; i++) {
113 int j = nextInt(size);
114 Object obj = list.get(i);
115
116 list.set(i, list.get(i + j));
117 list.set(i + j, obj);
118
119 size--;
120 }
121 }
122
123 public void randomize(Object array[]) {
124 int length = array.length;
125
126 for(int i = 0; i < length - 1; i++) {
127 int x = nextInt(length);
128 Object y = array[i];
129
130 array[i] = array[i + x];
131 array[i + x] = y;
132
133 length--;
134 }
135 }
136
137 public String randomize(String s) {
138 if (s == null) {
139 return null;
140 }
141
142 char[] array = s.toCharArray();
143
144 randomize(array);
145
146 return new String(array);
147 }
148
149 private static Randomizer _instance = new Randomizer();
150
151 }