001    /**
002     * Copyright (c) 2000-2010 Liferay, Inc. All rights reserved.
003     *
004     * This library is free software; you can redistribute it and/or modify it under
005     * the terms of the GNU Lesser General Public License as published by the Free
006     * Software Foundation; either version 2.1 of the License, or (at your option)
007     * any later version.
008     *
009     * This library is distributed in the hope that it will be useful, but WITHOUT
010     * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
011     * FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more
012     * details.
013     */
014    
015    package com.liferay.portal.kernel.util;
016    
017    import com.liferay.portal.kernel.io.unsync.UnsyncBufferedReader;
018    
019    import java.io.File;
020    import java.io.FileReader;
021    import java.io.IOException;
022    
023    import java.util.Collection;
024    import java.util.Enumeration;
025    import java.util.HashSet;
026    import java.util.Iterator;
027    import java.util.List;
028    import java.util.Set;
029    
030    /**
031     * @author Brian Wing Shun Chan
032     */
033    public class SetUtil {
034    
035            public static <E> Set<E> fromArray(E[] array) {
036                    if ((array == null) || (array.length == 0)) {
037                            return new HashSet<E>();
038                    }
039    
040                    Set<E> set = new HashSet<E>(array.length);
041    
042                    for (int i = 0; i < array.length; i++) {
043                            set.add(array[i]);
044                    }
045    
046                    return set;
047            }
048    
049            public static Set<Long> fromArray(long[] array) {
050                    if ((array == null) || (array.length == 0)) {
051                            return new HashSet<Long>();
052                    }
053    
054                    Set<Long> set = new HashSet<Long>(array.length);
055    
056                    for (int i = 0; i < array.length; i++) {
057                            set.add(array[i]);
058                    }
059    
060                    return set;
061            }
062    
063            @SuppressWarnings("rawtypes")
064            public static <E> Set<E> fromCollection(Collection<E> c) {
065                    if ((c != null) && (Set.class.isAssignableFrom(c.getClass()))) {
066                            return (Set)c;
067                    }
068    
069                    if ((c == null) || (c.size() == 0)) {
070                            return new HashSet<E>();
071                    }
072    
073                    return new HashSet<E>(c);
074            }
075    
076            public static <E> Set<E> fromEnumeration(Enumeration<E> enu) {
077                    Set<E> set = new HashSet<E>();
078    
079                    while (enu.hasMoreElements()) {
080                            set.add(enu.nextElement());
081                    }
082    
083                    return set;
084            }
085    
086            public static Set<String> fromFile(File file) throws IOException {
087                    Set<String> set = new HashSet<String>();
088    
089                    UnsyncBufferedReader unsyncBufferedReader = new UnsyncBufferedReader(
090                            new FileReader(file));
091    
092                    String s = StringPool.BLANK;
093    
094                    while ((s = unsyncBufferedReader.readLine()) != null) {
095                            set.add(s);
096                    }
097    
098                    unsyncBufferedReader.close();
099    
100                    return set;
101            }
102    
103            public static Set<String> fromFile(String fileName) throws IOException {
104                    return fromFile(new File(fileName));
105            }
106    
107            public static <E> Set<E> fromIterator(Iterator<E> itr) {
108                    Set<E> set = new HashSet<E>();
109    
110                    while (itr.hasNext()) {
111                            set.add(itr.next());
112                    }
113    
114                    return set;
115            }
116    
117            public static <E> Set<E> fromList(List<E> array) {
118                    if ((array == null) || (array.size() == 0)) {
119                            return new HashSet<E>();
120                    }
121    
122                    return new HashSet<E>(array);
123            }
124    
125            public static Set<String> fromString(String s) {
126                    return fromArray(StringUtil.split(s, StringPool.NEW_LINE));
127            }
128    
129    }