Source code

001////////////////////////////////////////////////////////////////////////////////
002// checkstyle: Checks Java source code for adherence to a set of rules.
003// Copyright (C) 2001-2020 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.Collections;
026import java.util.Locale;
027import java.util.Map;
028import java.util.Optional;
029import java.util.ResourceBundle;
030import java.util.function.Consumer;
031import java.util.function.Predicate;
032import java.util.stream.Collectors;
033
034import com.puppycrawl.tools.checkstyle.api.DetailAST;
035import com.puppycrawl.tools.checkstyle.api.TokenTypes;
036
037/**
038 * Contains utility methods for tokens.
039 *
040 */
041public final class TokenUtil {
042
043    /** Maps from a token name to value. */
044    private static final Map<String, Integer> TOKEN_NAME_TO_VALUE;
045    /** Maps from a token value to name. */
046    private static final String[] TOKEN_VALUE_TO_NAME;
047
048    /** Array of all token IDs. */
049    private static final int[] TOKEN_IDS;
050
051    /** Prefix for exception when getting token by given id. */
052    private static final String TOKEN_ID_EXCEPTION_PREFIX = "given id ";
053
054    /** Prefix for exception when getting token by given name. */
055    private static final String TOKEN_NAME_EXCEPTION_PREFIX = "given name ";
056
057    // initialise the constants
058    static {
059        TOKEN_NAME_TO_VALUE = nameToValueMapFromPublicIntFields(TokenTypes.class);
060        TOKEN_VALUE_TO_NAME = valueToNameArrayFromNameToValueMap(TOKEN_NAME_TO_VALUE);
061        TOKEN_IDS = TOKEN_NAME_TO_VALUE.values().stream().mapToInt(Integer::intValue).toArray();
062    }
063
064    /** Stop instances being created. **/
065    private TokenUtil() {
066    }
067
068    /**
069     * Gets the value of a static or instance field of type int or of another primitive type
070     * convertible to type int via a widening conversion. Does not throw any checked exceptions.
071     * @param field from which the int should be extracted
072     * @param object to extract the int value from
073     * @return the value of the field converted to type int
074     * @throws IllegalStateException if this Field object is enforcing Java language access control
075     *         and the underlying field is inaccessible
076     * @see Field#getInt(Object)
077     */
078    public static int getIntFromField(Field field, Object object) {
079        try {
080            return field.getInt(object);
081        }
082        catch (final IllegalAccessException exception) {
083            throw new IllegalStateException(exception);
084        }
085    }
086
087    /**
088     * Creates a map of 'field name' to 'field value' from all {@code public} {@code int} fields
089     * of a class.
090     * @param cls source class
091     * @return unmodifiable name to value map
092     */
093    public static Map<String, Integer> nameToValueMapFromPublicIntFields(Class<?> cls) {
094        final Map<String, Integer> map = Arrays.stream(cls.getDeclaredFields())
095            .filter(fld -> Modifier.isPublic(fld.getModifiers()) && fld.getType() == Integer.TYPE)
096            .collect(Collectors.toMap(Field::getName, fld -> getIntFromField(fld, fld.getName())));
097        return Collections.unmodifiableMap(map);
098    }
099
100    /**
101     * Creates an array of map keys for quick value-to-name lookup for the map.
102     * @param map source map
103     * @return array of map keys
104     */
105    public static String[] valueToNameArrayFromNameToValueMap(Map<String, Integer> map) {
106        String[] valueToNameArray = CommonUtil.EMPTY_STRING_ARRAY;
107
108        for (Map.Entry<String, Integer> entry : map.entrySet()) {
109            final int value = entry.getValue();
110            // JavadocTokenTypes.EOF has value '-1' and is handled explicitly.
111            if (value >= 0) {
112                if (value >= valueToNameArray.length) {
113                    final String[] temp = new String[value + 1];
114                    System.arraycopy(valueToNameArray, 0, temp, 0, valueToNameArray.length);
115                    valueToNameArray = temp;
116                }
117                valueToNameArray[value] = entry.getKey();
118            }
119        }
120        return valueToNameArray;
121    }
122
123    /**
124     * Get total number of TokenTypes.
125     * @return total number of TokenTypes.
126     */
127    public static int getTokenTypesTotalNumber() {
128        return TOKEN_IDS.length;
129    }
130
131    /**
132     * Get all token IDs that are available in TokenTypes.
133     * @return array of token IDs
134     */
135    public static int[] getAllTokenIds() {
136        final int[] safeCopy = new int[TOKEN_IDS.length];
137        System.arraycopy(TOKEN_IDS, 0, safeCopy, 0, TOKEN_IDS.length);
138        return safeCopy;
139    }
140
141    /**
142     * Returns the name of a token for a given ID.
143     * @param id the ID of the token name to get
144     * @return a token name
145     * @throws IllegalArgumentException when id is not valid
146     */
147    public static String getTokenName(int id) {
148        if (id > TOKEN_VALUE_TO_NAME.length - 1) {
149            throw new IllegalArgumentException(TOKEN_ID_EXCEPTION_PREFIX + id);
150        }
151        final String name = TOKEN_VALUE_TO_NAME[id];
152        if (name == null) {
153            throw new IllegalArgumentException(TOKEN_ID_EXCEPTION_PREFIX + id);
154        }
155        return name;
156    }
157
158    /**
159     * Returns the ID of a token for a given name.
160     * @param name the name of the token ID to get
161     * @return a token ID
162     * @throws IllegalArgumentException when id is null
163     */
164    public static int getTokenId(String name) {
165        final Integer id = TOKEN_NAME_TO_VALUE.get(name);
166        if (id == null) {
167            throw new IllegalArgumentException(TOKEN_NAME_EXCEPTION_PREFIX + name);
168        }
169        return id;
170    }
171
172    /**
173     * Returns the short description of a token for a given name.
174     * @param name the name of the token ID to get
175     * @return a short description
176     * @throws IllegalArgumentException when name is unknown
177     */
178    public static String getShortDescription(String name) {
179        if (!TOKEN_NAME_TO_VALUE.containsKey(name)) {
180            throw new IllegalArgumentException(TOKEN_NAME_EXCEPTION_PREFIX + name);
181        }
182
183        final String tokenTypes =
184            "com.puppycrawl.tools.checkstyle.api.tokentypes";
185        final ResourceBundle bundle = ResourceBundle.getBundle(tokenTypes, Locale.ROOT);
186        return bundle.getString(name);
187    }
188
189    /**
190     * Is argument comment-related type (SINGLE_LINE_COMMENT,
191     * BLOCK_COMMENT_BEGIN, BLOCK_COMMENT_END, COMMENT_CONTENT).
192     * @param type
193     *        token type.
194     * @return true if type is comment-related type.
195     */
196    public static boolean isCommentType(int type) {
197        return type == TokenTypes.SINGLE_LINE_COMMENT
198                || type == TokenTypes.BLOCK_COMMENT_BEGIN
199                || type == TokenTypes.BLOCK_COMMENT_END
200                || type == TokenTypes.COMMENT_CONTENT;
201    }
202
203    /**
204     * Is argument comment-related type name (SINGLE_LINE_COMMENT,
205     * BLOCK_COMMENT_BEGIN, BLOCK_COMMENT_END, COMMENT_CONTENT).
206     * @param type
207     *        token type name.
208     * @return true if type is comment-related type name.
209     */
210    public static boolean isCommentType(String type) {
211        return isCommentType(getTokenId(type));
212    }
213
214    /**
215     * Finds the first {@link Optional} child token of {@link DetailAST} root node
216     * which matches the given predicate.
217     * @param root root node.
218     * @param predicate predicate.
219     * @return {@link Optional} of {@link DetailAST} node which matches the predicate.
220     */
221    public static Optional<DetailAST> findFirstTokenByPredicate(DetailAST root,
222                                                                Predicate<DetailAST> predicate) {
223        Optional<DetailAST> result = Optional.empty();
224        for (DetailAST ast = root.getFirstChild(); ast != null; ast = ast.getNextSibling()) {
225            if (predicate.test(ast)) {
226                result = Optional.of(ast);
227                break;
228            }
229        }
230        return result;
231    }
232
233    /**
234     * Performs an action for each child of {@link DetailAST} root node
235     * which matches the given token type.
236     * @param root root node.
237     * @param type token type to match.
238     * @param action action to perform on the nodes.
239     */
240    public static void forEachChild(DetailAST root, int type, Consumer<DetailAST> action) {
241        for (DetailAST ast = root.getFirstChild(); ast != null; ast = ast.getNextSibling()) {
242            if (ast.getType() == type) {
243                action.accept(ast);
244            }
245        }
246    }
247
248}