[927] | 1 | // Copyright 2012 Georg-August-Universität Göttingen, Germany
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| 2 | //
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| 3 | // Licensed under the Apache License, Version 2.0 (the "License");
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| 4 | // you may not use this file except in compliance with the License.
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| 5 | // You may obtain a copy of the License at
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| 6 | //
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| 7 | // http://www.apache.org/licenses/LICENSE-2.0
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| 8 | //
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| 9 | // Unless required by applicable law or agreed to in writing, software
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| 10 | // distributed under the License is distributed on an "AS IS" BASIS,
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| 11 | // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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| 12 | // See the License for the specific language governing permissions and
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| 13 | // limitations under the License.
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| 14 |
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[1] | 15 | package de.ugoe.cs.util;
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| 16 |
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[1243] | 17 | import java.util.ArrayList;
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| 18 | import java.util.List;
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| 19 |
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[175] | 20 | /**
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| 21 | * <p>
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| 22 | * Helper class that provides methods to simplify working with {@link String}s.
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| 23 | * </p>
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| 24 | *
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| 25 | * @author Steffen Herbold
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| 26 | * @version 1.0
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| 27 | */
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[1] | 28 | final public class StringTools {
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| 29 |
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[1241] | 30 | /**
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| 31 | * <p>
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| 32 | * Private constructor to prevent initializing of the class.
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| 33 | * </p>
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| 34 | */
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| 35 | private StringTools() {
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[330] | 36 |
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[1241] | 37 | }
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[330] | 38 |
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[1241] | 39 | /**
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| 40 | * <p>
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| 41 | * Simplifies use of operation system specific line separators.
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| 42 | * </p>
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| 43 | */
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| 44 | public final static String ENDLINE = System.getProperty("line.separator");
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[175] | 45 |
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[1241] | 46 | /**
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| 47 | * <p>
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| 48 | * Replaces all occurrences of {@literal &, <, >, ', and "} with their respective XML entities
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| 49 | * {@literal &, <, >, ', and "} without destroying already existing
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| 50 | * entities.
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| 51 | * </p>
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| 52 | *
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| 53 | * @param str
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| 54 | * String where the XML entities are to be replaced
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| 55 | * @return new String, where the XML entities are used instead of the literals
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| 56 | */
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| 57 | public static String xmlEntityReplacement(String str) {
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| 58 | String result = str;
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| 59 | if (result != null && !"".equals(result)) {
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| 60 | result = result.replaceAll("&(?!(?:lt|gt|apos|quot|amp);)", "&");
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| 61 | result = result.replaceAll("<", "<");
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| 62 | result = result.replaceAll(">", ">");
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| 63 | result = result.replaceAll("'", "'");
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| 64 | result = result.replaceAll("\"", """);
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| 65 | }
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| 66 | return result;
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| 67 | }
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[1243] | 68 |
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| 69 | /**
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| 70 | * <p>
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| 71 | * Performs an auto completion of the provided prefix using the given potential completions.
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| 72 | * The method searches for all completions that start with the given prefix and stores them in
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| 73 | * a subset. It then extends the prefix with characters of the subset of completions as long as
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| 74 | * the prefix still prefixes all completions in the subset. The result is then returned. If
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| 75 | * there is no matching completion or if there are several matching completions differing
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| 76 | * in the succeeding letter, the prefix is returned as is. If there is only one matching
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| 77 | * completion this completion is returned.
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| 78 | * </p>
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| 79 | *
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| 80 | * @param prefix the prefix to be further completed
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| 81 | * @param completions the potential completions of the prefix
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| 82 | *
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| 83 | * @return as described
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| 84 | */
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| 85 | public static String autocomplete(String prefix, String[] completions) {
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| 86 | List<String> matchingCompletions = new ArrayList<String>();
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| 87 | for (String completion : completions) {
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| 88 | if (completion.startsWith(prefix)) {
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| 89 | matchingCompletions.add(completion);
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| 90 | }
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| 91 | }
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| 92 |
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| 93 | StringBuffer completedPrefix = new StringBuffer(prefix);
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| 94 |
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| 95 | boolean foundCompletion = false;
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| 96 |
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| 97 | while (!foundCompletion) {
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| 98 | char nextCompletionChar = 0;
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| 99 | for (String completion : matchingCompletions) {
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| 100 | if (completion.length() > completedPrefix.length()) {
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| 101 | if (nextCompletionChar == 0) {
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| 102 | nextCompletionChar = completion.charAt(completedPrefix.length());
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| 103 | }
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| 104 | else if (nextCompletionChar != completion.charAt(completedPrefix.length())) {
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| 105 | foundCompletion = true;
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| 106 | }
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| 107 | }
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| 108 | else {
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| 109 | foundCompletion = true;
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| 110 | }
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| 111 | }
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| 112 |
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| 113 | if (!foundCompletion && (nextCompletionChar != 0)) {
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| 114 | completedPrefix.append(nextCompletionChar);
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| 115 | }
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| 116 | else {
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| 117 | foundCompletion = true;
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| 118 | }
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| 119 | }
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| 120 |
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| 121 | return completedPrefix.toString();
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| 122 | }
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[1] | 123 | }
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