1 ///////////////////////////////////////////////////////////////////////////////////////////////
2 // checkstyle: Checks Java source code and other text files for adherence to a set of rules.
3 // Copyright (C) 2001-2026 the original author or authors.
4 //
5 // This library is free software; you can redistribute it and/or
6 // modify it under the terms of the GNU Lesser General Public
7 // License as published by the Free Software Foundation; either
8 // version 2.1 of the License, or (at your option) any later version.
9 //
10 // This library is distributed in the hope that it will be useful,
11 // but WITHOUT ANY WARRANTY; without even the implied warranty of
12 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 // Lesser General Public License for more details.
14 //
15 // You should have received a copy of the GNU Lesser General Public
16 // License along with this library; if not, write to the Free Software
17 // Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
18 ///////////////////////////////////////////////////////////////////////////////////////////////
19
20 package com.puppycrawl.tools.checkstyle.checks;
21
22 import java.io.File;
23 import java.io.IOException;
24 import java.io.InputStream;
25 import java.io.Serial;
26 import java.nio.file.Files;
27 import java.util.ArrayList;
28 import java.util.Collections;
29 import java.util.Enumeration;
30 import java.util.Iterator;
31 import java.util.List;
32 import java.util.Properties;
33 import java.util.regex.Matcher;
34 import java.util.regex.Pattern;
35
36 import com.puppycrawl.tools.checkstyle.StatelessCheck;
37 import com.puppycrawl.tools.checkstyle.api.AbstractFileSetCheck;
38 import com.puppycrawl.tools.checkstyle.api.FileText;
39
40 /**
41 * <div>
42 * Detects if keys in properties files are in correct order.
43 * </div>
44 *
45 * <p>
46 * Rationale: Sorted properties make it easy for people to find required properties by name
47 * in file. This makes it easier to merge. While there are no problems at runtime.
48 * This check is valuable only on files with string resources where order of lines
49 * does not matter at all, but this can be improved.
50 * E.g.: checkstyle/src/main/resources/com/puppycrawl/tools/checkstyle/messages.properties
51 * You may suppress warnings of this check for files that have a logical structure like
52 * build files or log4j configuration files. See SuppressionFilter.
53 * </p>
54 * <div class="wrapper">
55 * <pre>
56 * <suppress checks="OrderedProperties"
57 * files="log4j.properties|ResourceBundle/Bug.*.properties|logging.properties"/>
58 * </pre>
59 * </div>
60 *
61 * <p>Known limitation: The key should not contain a newline.
62 * The string compare will work, but not the line number reporting.</p>
63 *
64 * @since 8.22
65 */
66 @StatelessCheck
67 public class OrderedPropertiesCheck extends AbstractFileSetCheck {
68
69 /**
70 * Localization key for check violation.
71 */
72 public static final String MSG_KEY = "properties.notSorted.property";
73 /**
74 * Localization key for IO exception occurred on file open.
75 */
76 public static final String MSG_IO_EXCEPTION_KEY = "unable.open.cause";
77 /**
78 * Pattern matching single space.
79 */
80 private static final Pattern SPACE_PATTERN = Pattern.compile(" ");
81
82 /**
83 * Construct the check with default values.
84 */
85 public OrderedPropertiesCheck() {
86 setFileExtensions("properties");
87 }
88
89 /**
90 * Setter to specify the file extensions of the files to process.
91 *
92 * @param extensions the set of file extensions. A missing
93 * initial '.' character of an extension is automatically added.
94 * @throws IllegalArgumentException is argument is null
95 */
96 @Override
97 public final void setFileExtensions(String... extensions) {
98 super.setFileExtensions(extensions);
99 }
100
101 /**
102 * Processes the file and check order.
103 *
104 * @param file the file to be processed
105 * @param fileText the contents of the file.
106 */
107 @Override
108 protected void processFiltered(File file, FileText fileText) {
109 final SequencedProperties properties = new SequencedProperties();
110 try (InputStream inputStream = Files.newInputStream(file.toPath())) {
111 properties.load(inputStream);
112 }
113 catch (IOException | IllegalArgumentException exc) {
114 log(1, MSG_IO_EXCEPTION_KEY, file.getPath(), exc.getLocalizedMessage());
115 }
116
117 String previousProp = "";
118 int startLineNo = 0;
119
120 final Iterator<Object> propertyIterator = properties.keys().asIterator();
121
122 while (propertyIterator.hasNext()) {
123
124 final String propKey = (String) propertyIterator.next();
125
126 if (String.CASE_INSENSITIVE_ORDER.compare(previousProp, propKey) > 0) {
127
128 final int lineNo = getLineNumber(startLineNo, fileText, previousProp, propKey);
129 log(lineNo + 1, MSG_KEY, propKey, previousProp);
130 // start searching at position of the last reported validation
131 startLineNo = lineNo;
132 }
133
134 previousProp = propKey;
135 }
136 }
137
138 /**
139 * Method returns the index number where the key is detected (starting at 0).
140 * To assure that we get the correct line it starts at the point
141 * of the last occurrence.
142 * Also, the previousProp should be in file before propKey.
143 *
144 * @param startLineNo start searching at line
145 * @param fileText {@link FileText} object contains the lines to process
146 * @param previousProp key name found last iteration, works only if valid
147 * @param propKey key name to look for
148 * @return index number of first occurrence. If no key found in properties file, 0 is returned
149 */
150 private static int getLineNumber(int startLineNo, FileText fileText,
151 String previousProp, String propKey) {
152 final int indexOfPreviousProp = getIndex(startLineNo, fileText, previousProp);
153 return getIndex(indexOfPreviousProp, fileText, propKey);
154 }
155
156 /**
157 * Inner method to get the index number of the position of keyName.
158 *
159 * @param startLineNo start searching at line
160 * @param fileText {@link FileText} object contains the lines to process
161 * @param keyName key name to look for
162 * @return index number of first occurrence. If no key found in properties file, 0 is returned
163 */
164 private static int getIndex(int startLineNo, FileText fileText, String keyName) {
165 final Pattern keyPattern = getKeyPattern(keyName);
166 int indexNumber = 0;
167 final Matcher matcher = keyPattern.matcher("");
168 for (int index = startLineNo; index < fileText.size(); index++) {
169 final String line = fileText.get(index);
170 matcher.reset(line);
171 if (matcher.matches()) {
172 indexNumber = index;
173 break;
174 }
175 }
176 return indexNumber;
177 }
178
179 /**
180 * Method returns regular expression pattern given key name.
181 *
182 * @param keyName
183 * key name to look for
184 * @return regular expression pattern given key name
185 */
186 private static Pattern getKeyPattern(String keyName) {
187 final String keyPatternString = "^" + SPACE_PATTERN.matcher(keyName)
188 .replaceAll(Matcher.quoteReplacement("\\\\ ")) + "[\\s:=].*";
189 return Pattern.compile(keyPatternString);
190 }
191
192 /**
193 * Private property implementation that keeps order of properties like in file.
194 *
195 * @noinspection ClassExtendsConcreteCollection
196 * @noinspectionreason ClassExtendsConcreteCollection - we require order from
197 * file to be maintained by {@code put} method
198 */
199 private static final class SequencedProperties extends Properties {
200
201 /** A unique serial version identifier. */
202 @Serial
203 private static final long serialVersionUID = 1L;
204
205 /**
206 * Holding the keys in the same order as in the file.
207 */
208 private final List<Object> keyList = new ArrayList<>();
209
210 /**
211 * Returns a copy of the keys.
212 *
213 * @noinspection SynchronizedMethod
214 * @noinspectionreason SynchronizedMethod - synchronized keyword is required
215 * to override the synchronized keys() method from Hashtable parent class,
216 * maintaining thread-safety contract
217 */
218 @Override
219 public synchronized Enumeration<Object> keys() {
220 return Collections.enumeration(keyList);
221 }
222
223 /**
224 * Puts the value into list by its key.
225 *
226 * @param key the hashtable key
227 * @param value the value
228 * @return the previous value of the specified key in this hashtable,
229 * or null if it did not have one
230 * @throws NullPointerException - if the key or value is null
231 */
232 @Override
233 public synchronized Object put(Object key, Object value) {
234 keyList.add(key);
235
236 return null;
237 }
238 }
239 }