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.utils;
021
022import java.lang.reflect.Field;
023import java.lang.reflect.Modifier;
024import java.util.Arrays;
025import java.util.BitSet;
026import java.util.Locale;
027import java.util.Map;
028import java.util.Optional;
029import java.util.ResourceBundle;
030import java.util.Set;
031import java.util.function.Consumer;
032import java.util.function.Predicate;
033import java.util.stream.Collectors;
034import java.util.stream.IntStream;
035
036import com.puppycrawl.tools.checkstyle.api.DetailAST;
037import com.puppycrawl.tools.checkstyle.api.TokenTypes;
038
039/**
040 * Contains utility methods for tokens.
041 *
042 */
043public final class TokenUtil {
044
045    /** Maps from a token name to value. */
046    private static final Map<String, Integer> TOKEN_NAME_TO_VALUE;
047    /** Maps from a token value to name. */
048    private static final Map<Integer, String> TOKEN_VALUE_TO_NAME;
049
050    /** Array of all token IDs. */
051    private static final int[] TOKEN_IDS;
052
053    /** Format for exception message when getting token by given id. */
054    private static final String TOKEN_ID_EXCEPTION_FORMAT = "unknown TokenTypes id '%s'";
055
056    /** Format for exception message when getting token by given name. */
057    private static final String TOKEN_NAME_EXCEPTION_FORMAT = "unknown TokenTypes value '%s'";
058
059    // initialise the constants
060    static {
061        TOKEN_NAME_TO_VALUE = nameToValueMapFromPublicIntFields(TokenTypes.class);
062        TOKEN_VALUE_TO_NAME = invertMap(TOKEN_NAME_TO_VALUE);
063        TOKEN_IDS = TOKEN_NAME_TO_VALUE.values().stream().mapToInt(Integer::intValue).toArray();
064    }
065
066    /** Stop instances being created. **/
067    private TokenUtil() {
068    }
069
070    /**
071     * Gets the IDENT token from the given AST node.
072     *
073     * <p>This method must only be used for AST types where the IDENT token
074     * is guaranteed to NEVER be null. The known types are:
075     * <ul>
076     * <li>{@link TokenTypes#METHOD_DEF}</li>
077     * <li>{@link TokenTypes#CLASS_DEF}</li>
078     * <li>{@link TokenTypes#VARIABLE_DEF}</li>
079     * <li>{@link TokenTypes#PARAMETER_DEF}, <b>but not receiver parameter</b>.</li>
080     * <li>{@link TokenTypes#INTERFACE_DEF}</li>
081     * <li>{@link TokenTypes#ENUM_DEF}</li>
082     * <li>{@link TokenTypes#ANNOTATION_DEF}</li>
083     * <li>{@link TokenTypes#RECORD_DEF}</li>
084     * <li>{@link TokenTypes#LITERAL_CATCH}</li>
085     * </ul>
086     *
087     * @param ast the AST node.
088     * @return the IDENT token (not null).
089     */
090    public static DetailAST getIdent(DetailAST ast) {
091        return NullUtil.notNull(ast.findFirstToken(TokenTypes.IDENT));
092    }
093
094    /**
095     * Gets the value of a static or instance field of type int or of another primitive type
096     * convertible to type int via a widening conversion. Does not throw any checked exceptions.
097     *
098     * @param field from which the int should be extracted
099     * @param object to extract the int value from
100     * @return the value of the field converted to type int
101     * @throws IllegalStateException if this Field object is enforcing Java language access control
102     *         and the underlying field is inaccessible
103     * @see Field#getInt(Object)
104     */
105    public static int getIntFromField(Field field, Object object) {
106        try {
107            return field.getInt(object);
108        }
109        catch (final IllegalAccessException exception) {
110            throw new IllegalStateException(exception);
111        }
112    }
113
114    /**
115     * Creates a map of 'field name' to 'field value' from all {@code public} {@code int} fields
116     * of a class.
117     *
118     * @param cls source class
119     * @return unmodifiable name to value map
120     */
121    public static Map<String, Integer> nameToValueMapFromPublicIntFields(Class<?> cls) {
122        return Arrays.stream(cls.getDeclaredFields())
123            .filter(fld -> Modifier.isPublic(fld.getModifiers()) && fld.getType() == Integer.TYPE)
124            .collect(Collectors.toUnmodifiableMap(
125                Field::getName, fld -> getIntFromField(fld, null))
126            );
127    }
128
129    /**
130     * Inverts a given map by exchanging each entry's key and value.
131     *
132     * @param map source map
133     * @return inverted map
134     */
135    public static Map<Integer, String> invertMap(Map<String, Integer> map) {
136        return map.entrySet().stream()
137            .collect(Collectors.toUnmodifiableMap(Map.Entry::getValue, Map.Entry::getKey));
138    }
139
140    /**
141     * Get total number of TokenTypes.
142     *
143     * @return total number of TokenTypes.
144     */
145    public static int getTokenTypesTotalNumber() {
146        return TOKEN_IDS.length;
147    }
148
149    /**
150     * Get all token IDs that are available in TokenTypes.
151     *
152     * @return array of token IDs
153     */
154    public static int[] getAllTokenIds() {
155        final int[] safeCopy = new int[TOKEN_IDS.length];
156        System.arraycopy(TOKEN_IDS, 0, safeCopy, 0, TOKEN_IDS.length);
157        return safeCopy;
158    }
159
160    /**
161     * Returns the name of a token for a given ID.
162     *
163     * @param id the ID of the token name to get
164     * @return a token name
165     * @throws IllegalArgumentException when id is not valid
166     */
167    public static String getTokenName(int id) {
168        final String name = TOKEN_VALUE_TO_NAME.get(id);
169        if (name == null) {
170            throw new IllegalArgumentException(
171                String.format(Locale.ROOT, TOKEN_ID_EXCEPTION_FORMAT, id));
172        }
173        return name;
174    }
175
176    /**
177     * Returns the ID of a token for a given name.
178     *
179     * @param name the name of the token ID to get
180     * @return a token ID
181     * @throws IllegalArgumentException when id is null
182     */
183    public static int getTokenId(String name) {
184        final Integer id = TOKEN_NAME_TO_VALUE.get(name);
185        if (id == null) {
186            throw new IllegalArgumentException(
187                String.format(Locale.ROOT, TOKEN_NAME_EXCEPTION_FORMAT, name));
188        }
189        return id;
190    }
191
192    /**
193     * Returns the short description of a token for a given name.
194     *
195     * @param name the name of the token ID to get
196     * @return a short description
197     * @throws IllegalArgumentException when name is unknown
198     */
199    public static String getShortDescription(String name) {
200        if (!TOKEN_NAME_TO_VALUE.containsKey(name)) {
201            throw new IllegalArgumentException(
202                String.format(Locale.ROOT, TOKEN_NAME_EXCEPTION_FORMAT, name));
203        }
204
205        final String tokenTypes =
206            "com.puppycrawl.tools.checkstyle.api.tokentypes";
207        final ResourceBundle bundle = ResourceBundle.getBundle(tokenTypes, Locale.ROOT);
208        return bundle.getString(name);
209    }
210
211    /**
212     * Is argument comment-related type (SINGLE_LINE_COMMENT,
213     * BLOCK_COMMENT_BEGIN, BLOCK_COMMENT_END, COMMENT_CONTENT).
214     *
215     * @param type
216     *        token type.
217     * @return true if type is comment-related type.
218     */
219    public static boolean isCommentType(int type) {
220        return type == TokenTypes.SINGLE_LINE_COMMENT
221                || type == TokenTypes.BLOCK_COMMENT_BEGIN
222                || type == TokenTypes.BLOCK_COMMENT_END
223                || type == TokenTypes.COMMENT_CONTENT;
224    }
225
226    /**
227     * Is argument comment-related type name (SINGLE_LINE_COMMENT,
228     * BLOCK_COMMENT_BEGIN, BLOCK_COMMENT_END, COMMENT_CONTENT).
229     *
230     * @param type
231     *        token type name.
232     * @return true if type is comment-related type name.
233     */
234    public static boolean isCommentType(String type) {
235        return isCommentType(getTokenId(type));
236    }
237
238    /**
239     * Finds the first {@link Optional} child token of {@link DetailAST} root node
240     * which matches the given predicate.
241     *
242     * @param root root node.
243     * @param predicate predicate.
244     * @return {@link Optional} of {@link DetailAST} node which matches the predicate.
245     */
246    public static Optional<DetailAST> findFirstTokenByPredicate(DetailAST root,
247                                                                Predicate<DetailAST> predicate) {
248        Optional<DetailAST> result = Optional.empty();
249        for (DetailAST ast = root.getFirstChild(); ast != null; ast = ast.getNextSibling()) {
250            if (predicate.test(ast)) {
251                result = Optional.of(ast);
252                break;
253            }
254        }
255        return result;
256    }
257
258    /**
259     * Performs an action for each child of {@link DetailAST} root node
260     * which matches the given token type.
261     *
262     * @param root root node.
263     * @param type token type to match.
264     * @param action action to perform on the nodes.
265     */
266    public static void forEachChild(DetailAST root, int type, Consumer<DetailAST> action) {
267        for (DetailAST ast = root.getFirstChild(); ast != null; ast = ast.getNextSibling()) {
268            if (ast.getType() == type) {
269                action.accept(ast);
270            }
271        }
272    }
273
274    /**
275     * Determines if two ASTs are on the same line.
276     *
277     * @param ast1   the first AST
278     * @param ast2   the second AST
279     *
280     * @return true if they are on the same line.
281     */
282    public static boolean areOnSameLine(DetailAST ast1, DetailAST ast2) {
283        return ast1.getLineNo() == ast2.getLineNo();
284    }
285
286    /**
287     * Is type declaration token type (CLASS_DEF, INTERFACE_DEF,
288     * ANNOTATION_DEF, ENUM_DEF, RECORD_DEF).
289     *
290     * @param type
291     *        token type.
292     * @return true if type is type declaration token type.
293     */
294    public static boolean isTypeDeclaration(int type) {
295        return type == TokenTypes.CLASS_DEF
296                || type == TokenTypes.INTERFACE_DEF
297                || type == TokenTypes.ANNOTATION_DEF
298                || type == TokenTypes.ENUM_DEF
299                || type == TokenTypes.RECORD_DEF;
300    }
301
302    /**
303     * Determines if the token type belongs to the given types.
304     *
305     * @param type the Token Type to check
306     * @param types the acceptable types
307     *
308     * @return true if type matches one of the given types.
309     */
310    public static boolean isOfType(int type, int... types) {
311        boolean matching = false;
312        for (int tokenType : types) {
313            if (tokenType == type) {
314                matching = true;
315                break;
316            }
317        }
318        return matching;
319    }
320
321    /**
322     * Determines if the token type belongs to the given types.
323     *
324     * @param type the Token Type to check
325     * @param types the acceptable types
326     *
327     * @return true if type matches one of the given types.
328     */
329    public static boolean isOfType(int type, Set<Integer> types) {
330        return types.contains(type);
331    }
332
333    /**
334     * Determines if the AST belongs to the given types.
335     *
336     * @param ast the AST node to check
337     * @param types the acceptable types
338     *
339     * @return true if type matches one of the given types.
340     */
341    public static boolean isOfType(DetailAST ast, int... types) {
342        return ast != null && isOfType(ast.getType(), types);
343    }
344
345    /**
346     * Determines if given AST is a root node, i.e. if the type
347     * of the token we are checking is {@code COMPILATION_UNIT}.
348     *
349     * @param ast AST to check
350     * @return true if AST is a root node
351     */
352    public static boolean isRootNode(DetailAST ast) {
353        return ast.getType() == TokenTypes.COMPILATION_UNIT;
354    }
355
356    /**
357     * Checks if a token type is a literal true or false.
358     *
359     * @param tokenType the TokenType
360     * @return true if tokenType is LITERAL_TRUE or LITERAL_FALSE
361     */
362    public static boolean isBooleanLiteralType(final int tokenType) {
363        final boolean isTrue = tokenType == TokenTypes.LITERAL_TRUE;
364        final boolean isFalse = tokenType == TokenTypes.LITERAL_FALSE;
365        return isTrue || isFalse;
366    }
367
368    /**
369     * Creates a new {@code BitSet} from array of tokens.
370     *
371     * @param tokens to initialize the BitSet
372     * @return tokens as BitSet
373     */
374    public static BitSet asBitSet(int... tokens) {
375        return IntStream.of(tokens)
376                .collect(BitSet::new, BitSet::set, BitSet::or);
377    }
378
379    /**
380     * Creates a new {@code BitSet} from array of tokens.
381     *
382     * @param tokens to initialize the BitSet
383     * @return tokens as BitSet
384     */
385    public static BitSet asBitSet(String... tokens) {
386        return Arrays.stream(tokens)
387                .map(String::trim)
388                .filter(Predicate.not(String::isEmpty))
389                .mapToInt(TokenUtil::getTokenId)
390                .collect(BitSet::new, BitSet::set, BitSet::or);
391    }
392
393}