1
22
23 package com.liferay.util;
24
25 import com.liferay.portal.kernel.util.StringMaker;
26 import com.liferay.portal.kernel.util.StringPool;
27 import com.liferay.portal.kernel.util.StringUtil;
28
29 import java.io.BufferedReader;
30 import java.io.File;
31 import java.io.FileReader;
32 import java.io.IOException;
33
34 import java.util.ArrayList;
35 import java.util.Collection;
36 import java.util.Comparator;
37 import java.util.Enumeration;
38 import java.util.Iterator;
39 import java.util.List;
40 import java.util.Set;
41 import java.util.TreeSet;
42
43
49 public class ListUtil {
50
51 public static List copy(List master) {
52 if (master == null) {
53 return null;
54 }
55
56 List copy = new ArrayList(master.size());
57
58 copy(master, copy);
59
60 return copy;
61 }
62
63 public static void copy(List master, List copy) {
64 if ((master == null) || (copy == null)) {
65 return;
66 }
67
68 copy.clear();
69
70 Iterator itr = master.iterator();
71
72 while (itr.hasNext()) {
73 Object obj = itr.next();
74
75 copy.add(obj);
76 }
77 }
78
79 public static void distinct(List list) {
80 distinct(list, null);
81 }
82
83 public static void distinct(List list, Comparator comparator) {
84 if ((list == null) || (list.size() == 0)) {
85 return;
86 }
87
88 Set set = null;
89
90 if (comparator == null) {
91 set = new TreeSet();
92 }
93 else {
94 set = new TreeSet(comparator);
95 }
96
97 Iterator itr = list.iterator();
98
99 while (itr.hasNext()) {
100 Object obj = itr.next();
101
102 if (set.contains(obj)) {
103 itr.remove();
104 }
105 else {
106 set.add(obj);
107 }
108 }
109 }
110
111 public static List fromArray(Object[] array) {
112 if ((array == null) || (array.length == 0)) {
113 return new ArrayList();
114 }
115
116 List list = new ArrayList(array.length);
117
118 for (int i = 0; i < array.length; i++) {
119 list.add(array[i]);
120 }
121
122 return list;
123 }
124
125 public static List fromCollection(Collection c) {
126 if ((c != null) && (c instanceof List)) {
127 return (List)c;
128 }
129
130 if ((c == null) || (c.size() == 0)) {
131 return new ArrayList();
132 }
133
134 List list = new ArrayList(c.size());
135
136 Iterator itr = c.iterator();
137
138 while (itr.hasNext()) {
139 list.add(itr.next());
140 }
141
142 return list;
143 }
144
145 public static List fromEnumeration(Enumeration enu) {
146 List list = new ArrayList();
147
148 while (enu.hasMoreElements()) {
149 Object obj = enu.nextElement();
150
151 list.add(obj);
152 }
153
154 return list;
155 }
156
157 public static List fromFile(String fileName) throws IOException {
158 return fromFile(new File(fileName));
159 }
160
161 public static List fromFile(File file) throws IOException {
162 List list = new ArrayList();
163
164 BufferedReader br = new BufferedReader(new FileReader(file));
165
166 String s = StringPool.BLANK;
167
168 while ((s = br.readLine()) != null) {
169 list.add(s);
170 }
171
172 br.close();
173
174 return list;
175 }
176
177 public static List fromString(String s) {
178 return fromArray(StringUtil.split(s, StringPool.NEW_LINE));
179 }
180
181 public static List subList(List list, int begin, int end) {
182 List newList = new ArrayList();
183
184 int normalizedSize = list.size() - 1;
185
186 if ((begin < 0) || (begin > normalizedSize) || (end < 0) ||
187 (begin > end)) {
188
189 return newList;
190 }
191
192 for (int i = begin; i < end && i <= normalizedSize; i++) {
193 newList.add(list.get(i));
194 }
195
196 return newList;
197 }
198
199 public static String toString(List list, String param) {
200 return toString(list, param, StringPool.COMMA);
201 }
202
203 public static String toString(List list, String param, String delimiter) {
204 StringMaker sm = new StringMaker();
205
206 for (int i = 0; i < list.size(); i++) {
207 Object bean = list.get(i);
208
209 Object value = BeanUtil.getObject(bean, param);
210
211 if (value == null) {
212 value = StringPool.BLANK;
213 }
214
215 sm.append(value.toString());
216
217 if ((i + 1) != list.size()) {
218 sm.append(delimiter);
219 }
220 }
221
222 return sm.toString();
223 }
224
225 }