Source code

001///////////////////////////////////////////////////////////////////////////////////////////////
002// checkstyle: Checks Java source code and other text files for adherence to a set of rules.
003// Copyright (C) 2001-2026 the original author or authors.
004//
005// This library is free software; you can redistribute it and/or
006// modify it under the terms of the GNU Lesser General Public
007// License as published by the Free Software Foundation; either
008// version 2.1 of the License, or (at your option) any later version.
009//
010// This library is distributed in the hope that it will be useful,
011// but WITHOUT ANY WARRANTY; without even the implied warranty of
012// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
013// Lesser General Public License for more details.
014//
015// You should have received a copy of the GNU Lesser General Public
016// License along with this library; if not, write to the Free Software
017// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
018///////////////////////////////////////////////////////////////////////////////////////////////
019
020package com.puppycrawl.tools.checkstyle.checks;
021
022import java.io.File;
023import java.io.IOException;
024import java.io.InputStream;
025import java.io.Serial;
026import java.nio.file.Files;
027import java.util.ArrayList;
028import java.util.Collections;
029import java.util.Enumeration;
030import java.util.Iterator;
031import java.util.List;
032import java.util.Properties;
033import java.util.regex.Matcher;
034import java.util.regex.Pattern;
035
036import com.puppycrawl.tools.checkstyle.StatelessCheck;
037import com.puppycrawl.tools.checkstyle.api.AbstractFileSetCheck;
038import com.puppycrawl.tools.checkstyle.api.FileText;
039
040/**
041 * <div>
042 * Detects if keys in properties files are in correct order.
043 * </div>
044 *
045 * <p>
046 *   Rationale: Sorted properties make it easy for people to find required properties by name
047 *   in file. This makes it easier to merge. While there are no problems at runtime.
048 *   This check is valuable only on files with string resources where order of lines
049 *   does not matter at all, but this can be improved.
050 *   E.g.: checkstyle/src/main/resources/com/puppycrawl/tools/checkstyle/messages.properties
051 *   You may suppress warnings of this check for files that have a logical structure like
052 *   build files or log4j configuration files. See SuppressionFilter.
053 * </p>
054 * <div class="wrapper">
055 * <pre>
056 * &lt;suppress checks="OrderedProperties"
057 *   files="log4j.properties|ResourceBundle/Bug.*.properties|logging.properties"/&gt;
058 * </pre>
059 * </div>
060 *
061 * <p>Known limitation: The key should not contain a newline.
062 * The string compare will work, but not the line number reporting.</p>
063 *
064 * @since 8.22
065 */
066@StatelessCheck
067public class OrderedPropertiesCheck extends AbstractFileSetCheck {
068
069    /**
070     * Localization key for check violation.
071     */
072    public static final String MSG_KEY = "properties.notSorted.property";
073    /**
074     * Localization key for IO exception occurred on file open.
075     */
076    public static final String MSG_IO_EXCEPTION_KEY = "unable.open.cause";
077    /**
078     * Pattern matching single space.
079     */
080    private static final Pattern SPACE_PATTERN = Pattern.compile(" ");
081
082    /**
083     * Construct the check with default values.
084     */
085    public OrderedPropertiesCheck() {
086        setFileExtensions("properties");
087    }
088
089    /**
090     * Setter to specify the file extensions of the files to process.
091     *
092     * @param extensions the set of file extensions. A missing
093     *         initial '.' character of an extension is automatically added.
094     * @throws IllegalArgumentException is argument is null
095     */
096    @Override
097    public final void setFileExtensions(String... extensions) {
098        super.setFileExtensions(extensions);
099    }
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}