001/*
002 * (C) Copyright 2006-2016 Nuxeo SA (http://nuxeo.com/) and others.
003 *
004 * Licensed under the Apache License, Version 2.0 (the "License");
005 * you may not use this file except in compliance with the License.
006 * You may obtain a copy of the License at
007 *
008 *     http://www.apache.org/licenses/LICENSE-2.0
009 *
010 * Unless required by applicable law or agreed to in writing, software
011 * distributed under the License is distributed on an "AS IS" BASIS,
012 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
013 * See the License for the specific language governing permissions and
014 * limitations under the License.
015 *
016 * Contributors:
017 *     Nuxeo - initial API and implementation
018 */
019package org.nuxeo.common.utils;
020
021import java.security.SecureRandom;
022import java.util.ArrayList;
023import java.util.Date;
024import java.util.List;
025import java.util.Random;
026import java.util.regex.Pattern;
027
028/**
029 * Utils for identifier generation.
030 *
031 * @author <a href="mailto:[email protected]">Anahide Tchertchian</a>
032 */
033public final class IdUtils {
034
035    private static final String WORD_SPLITTING_REGEXP = "[^a-zA-Z0-9]+";
036
037    public static final String UUID_TYPE_4_REGEXP = "[a-f0-9]{8}-[a-f0-9]{4}-[a-f0-9]{4}-[a-f0-9]{4}-[a-f0-9]{12}";
038
039    private static final Random RANDOM = new SecureRandom();
040
041    // This is an utility class.
042    private IdUtils() {
043    }
044
045    /**
046     * Generates an unique string identifier.
047     */
048    public static String generateStringId() {
049        return String.valueOf(generateLongId());
050    }
051
052    /**
053     * Generates an unique long identifier.
054     */
055    public static long generateLongId() {
056        long r = RANDOM.nextLong();
057        if (r < 0) {
058            r = -r;
059        }
060        return r;
061    }
062
063    /**
064     * Generates an id from a non-null String.
065     * <p>
066     * Replaces accented characters from a string by their ascii equivalent, removes non alphanumerical characters and
067     * replaces spaces by the given wordSeparator character.
068     *
069     * @param s the original String
070     * @param wordSeparator the word separator to use (usually '-')
071     * @param lower if lower is true, remove upper case
072     * @param maxChars maximum longer of identifier characters
073     * @return the identifier String
074     */
075    public static String generateId(String s, String wordSeparator, boolean lower, int maxChars) {
076        s = StringUtils.toAscii(s);
077        s = s.trim();
078        if (lower) {
079            s = s.toLowerCase();
080        }
081        String[] words = s.split(WORD_SPLITTING_REGEXP);
082        // remove blank chars from words, did not get why they're not filtered
083        List<String> wordsList = new ArrayList<>();
084        for (String word : words) {
085            if (word != null && word.length() > 0) {
086                wordsList.add(word);
087            }
088        }
089        if (wordsList.isEmpty()) {
090            return generateStringId();
091        }
092        StringBuilder sb = new StringBuilder();
093        String id;
094        if (maxChars > 0) {
095            // be sure at least one word is used
096            sb.append(wordsList.get(0));
097            for (int i = 1; i < wordsList.size(); i++) {
098                String newWord = wordsList.get(i);
099                if (sb.length() + newWord.length() > maxChars) {
100                    break;
101                } else {
102                    sb.append(wordSeparator).append(newWord);
103                }
104            }
105            id = sb.toString();
106            id = id.substring(0, Math.min(id.length(), maxChars));
107        } else {
108            id = String.join(wordSeparator, wordsList);
109        }
110
111        return id;
112    }
113
114    /**
115     * Check if a given string has the pattern for UUID type 4
116     *
117     * @since 5.7
118     */
119    public static boolean isValidUUID(String uuid) {
120        return Pattern.compile(UUID_TYPE_4_REGEXP).matcher(uuid).matches();
121    }
122
123}