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1 /*
2  * Copyright (C) 2007-2010 Júlio Vilmar Gesser.
3  * Copyright (C) 2011, 2013-2016 The JavaParser Team.
4  *
5  * This file is part of JavaParser.
6  *
7  * JavaParser can be used either under the terms of
8  * a) the GNU Lesser General Public License as published by
9  *     the Free Software Foundation, either version 3 of the License, or
10  *     (at your option) any later version.
11  * b) the terms of the Apache License
12  *
13  * You should have received a copy of both licenses in LICENCE.LGPL and
14  * LICENCE.APACHE. Please refer to those files for details.
15  *
16  * JavaParser is distributed in the hope that it will be useful,
17  * but WITHOUT ANY WARRANTY; without even the implied warranty of
18  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
19  * GNU Lesser General Public License for more details.
20  */
21 
22 package com.github.javaparser.utils;
23 
24 import java.io.IOException;
25 import java.io.Reader;
26 import java.util.*;
27 import java.util.function.Predicate;
28 import java.util.function.Function;
29 
30 import static java.util.Arrays.*;
31 
32 /**
33  * Any kind of utility.
34  *
35  * @author Federico Tomassetti
36  */
37 public class Utils {
38     public static final String EOL = System.getProperty("line.separator");
39 
40     public static final Predicate<String> STRING_NOT_EMPTY = s -> !s.isEmpty();
41 
42     /**
43      * @deprecated This is no longer in use by JavaParser, please write your own replacement.
44      */
ensureNotNull(List<T> list)45     public static <T> List<T> ensureNotNull(List<T> list) {
46         return list == null ? new ArrayList<>() : list;
47     }
48 
isNullOrEmpty(Collection<E> collection)49     public static <E> boolean isNullOrEmpty(Collection<E> collection) {
50         return collection == null || collection.isEmpty();
51     }
52 
assertNotNull(T o)53     public static <T> T assertNotNull(T o) {
54         if (o == null) {
55             throw new AssertionError("A reference was unexpectedly null.");
56         }
57         return o;
58     }
59 
assertNonEmpty(String string)60     public static String assertNonEmpty(String string) {
61         if (string == null || string.isEmpty()) {
62             throw new AssertionError("A string was unexpectedly empty.");
63         }
64         return string;
65     }
66 
67     /**
68      * @return string with ASCII characters 10 and 13 replaced by the text "\n" and "\r".
69      */
escapeEndOfLines(String string)70     public static String escapeEndOfLines(String string) {
71         StringBuilder escapedString = new StringBuilder();
72         for (char c : string.toCharArray()) {
73             switch (c) {
74                 case '\n':
75                     escapedString.append("\\n");
76                     break;
77                 case '\r':
78                     escapedString.append("\\r");
79                     break;
80                 default:
81                     escapedString.append(c);
82             }
83         }
84         return escapedString.toString();
85     }
86 
readerToString(Reader reader)87     public static String readerToString(Reader reader) throws IOException {
88         final StringBuilder result = new StringBuilder();
89         final char[] buffer = new char[8 * 1024];
90         int numChars;
91 
92         while ((numChars = reader.read(buffer, 0, buffer.length)) > 0) {
93             result.append(buffer, 0, numChars);
94         }
95 
96         return result.toString();
97     }
98 
99     /**
100      * Puts varargs in a mutable list.
101      * This does not have the disadvantage of Arrays#asList that it has a static size.
102      *
103      * @deprecated This is no longer in use by JavaParser, please write your own replacement.
104      */
105     @Deprecated
arrayToList(T[] array)106     public static <T> List<T> arrayToList(T[] array) {
107         List<T> list = new LinkedList<>();
108         Collections.addAll(list, array);
109         return list;
110     }
111 
112     /**
113      * @deprecated use screamingToCamelCase
114      */
toCamelCase(String original)115     public static String toCamelCase(String original) {
116         return screamingToCamelCase(original);
117     }
118 
119     /**
120      * Transform a string to the camel case conversion.
121      * <p>
122      * For example "ABC_DEF" becomes "abcDef"
123      */
screamingToCamelCase(String original)124     public static String screamingToCamelCase(String original) {
125         StringBuilder sb = new StringBuilder();
126         String[] parts = original.toLowerCase().split("_");
127         for (int i = 0; i < parts.length; i++) {
128             sb.append(i == 0 ? parts[i] : capitalize(parts[i]));
129         }
130         return sb.toString();
131     }
132 
133 
134     /**
135      * @param input "aCamelCaseString"
136      * @return "A_CAMEL_CASE_STRING"
137      */
camelCaseToScreaming(String input)138     public static String camelCaseToScreaming(String input) {
139         if (input.isEmpty()) {
140             return "";
141         }
142         StringBuilder scream = new StringBuilder(input.substring(0, 1).toUpperCase());
143         for (char c : input.substring(1).toCharArray()) {
144             if (Character.isUpperCase(c)) {
145                 scream.append("_");
146             }
147             scream.append(Character.toUpperCase(c));
148         }
149         return scream.toString();
150     }
151 
152     /**
153      * Return the next word of the string, in other words it stops when a space is encountered.
154      */
nextWord(String string)155     public static String nextWord(String string) {
156         int index = 0;
157         while (index < string.length() && !Character.isWhitespace(string.charAt(index))) {
158             index++;
159         }
160         return string.substring(0, index);
161     }
162 
163     /**
164      * Make an indent by appending indentLevel tab characters to the builder.
165      */
indent(StringBuilder builder, int indentLevel)166     public static StringBuilder indent(StringBuilder builder, int indentLevel) {
167         for (int i = 0; i < indentLevel; i++) {
168             builder.append("\t");
169         }
170         return builder;
171     }
172 
173     /**
174      * Capitalizes the first character in the string.
175      */
capitalize(String s)176     public static String capitalize(String s) {
177         return stringTransformer(s, "capitalize", String::toUpperCase);
178     }
179 
180     /**
181      * Lower-cases the first character in the string.
182      */
decapitalize(String s)183     public static String decapitalize(String s) {
184         return stringTransformer(s, "decapitalize", String::toLowerCase);
185     }
186 
stringTransformer(String s, String operationDescription, Function<String, String> transformation)187     private static String stringTransformer(String s, String operationDescription, Function<String, String> transformation) {
188         if (s.isEmpty()) {
189             throw new IllegalArgumentException(String.format("You cannot %s an empty string", operationDescription));
190         }
191         return transformation.apply(s.substring(0, 1)) +
192                 s.substring(1);
193     }
194 
195     /**
196      * @return true if the value is null, an empty Optional, or an empty String.
197      */
valueIsNullOrEmpty(Object value)198     public static boolean valueIsNullOrEmpty(Object value) {
199         if (value == null) {
200             return true;
201         }
202         if (value instanceof Optional) {
203             if (((Optional) value).isPresent()) {
204                 value = ((Optional) value).get();
205             } else {
206                 return true;
207             }
208         }
209         if (value instanceof Collection) {
210             if (((Collection) value).isEmpty()) {
211                 return true;
212             }
213         }
214         return false;
215     }
216 
217     /**
218      * @return a set of the items.
219      */
set(T... items)220     public static <T> Set<T> set(T... items) {
221         return new HashSet<>(asList(items));
222     }
223 
224     /**
225      * @return content with all kinds of EOL characters replaced by endOfLineCharacter
226      */
normalizeEolInTextBlock(String content, String endOfLineCharacter)227     public static String normalizeEolInTextBlock(String content, String endOfLineCharacter) {
228         return content
229                 .replaceAll("\\R", endOfLineCharacter);
230     }
231 
232     /**
233      * @return the filename with the last "." and everything following it removed.
234      */
removeFileExtension(String filename)235     public static String removeFileExtension(String filename) {
236         int extensionIndex = filename.lastIndexOf(".");
237         if (extensionIndex == -1)
238             return filename;
239 
240         return filename.substring(0, extensionIndex);
241     }
242 
243     /**
244      * Like {@link String#trim()}, but only the trailing spaces.
245      */
trimTrailingSpaces(String line)246     public static String trimTrailingSpaces(String line) {
247         while (line.length() > 0 && line.charAt(line.length() - 1) <= 0x20) {
248             line = line.substring(0, line.length() - 1);
249         }
250         return line;
251     }
252 
253 }
254