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.whitespace;
021
022import com.puppycrawl.tools.checkstyle.StatelessCheck;
023import com.puppycrawl.tools.checkstyle.api.AbstractCheck;
024import com.puppycrawl.tools.checkstyle.api.DetailAST;
025import com.puppycrawl.tools.checkstyle.api.TokenTypes;
026import com.puppycrawl.tools.checkstyle.utils.CommonUtil;
027
028/**
029 * <div>
030 * Checks that a token is followed by whitespace, with the exception that it
031 * does not check for whitespace after the semicolon of an empty for iterator.
032 * Use Check
033 * <a href="https://checkstyle.org/checks/whitespace/emptyforiteratorpad.html">
034 * EmptyForIteratorPad</a> to validate empty for iterators.
035 * </div>
036 *
037 * @since 3.0
038 */
039@StatelessCheck
040public class WhitespaceAfterCheck
041    extends AbstractCheck {
042
043    /**
044     * A key is pointing to the warning message text in "messages.properties"
045     * file.
046     */
047    public static final String MSG_WS_NOT_FOLLOWED = "ws.notFollowed";
048
049    /**
050     * A key is pointing to the warning message text in "messages.properties"
051     * file.
052     */
053    public static final String MSG_WS_TYPECAST = "ws.typeCast";
054
055    /**
056     * Creates a new {@code WhitespaceAfterCheck} instance.
057     */
058    public WhitespaceAfterCheck() {
059        // no code by default
060    }
061
062    @Override
063    public int[] getDefaultTokens() {
064        return new int[] {
065            TokenTypes.COMMA,
066            TokenTypes.SEMI,
067            TokenTypes.TYPECAST,
068            TokenTypes.LITERAL_IF,
069            TokenTypes.LITERAL_ELSE,
070            TokenTypes.LITERAL_WHILE,
071            TokenTypes.LITERAL_DO,
072            TokenTypes.LITERAL_FOR,
073            TokenTypes.LITERAL_FINALLY,
074            TokenTypes.LITERAL_RETURN,
075            TokenTypes.LITERAL_YIELD,
076            TokenTypes.LITERAL_CATCH,
077            TokenTypes.DO_WHILE,
078            TokenTypes.ELLIPSIS,
079            TokenTypes.LITERAL_SWITCH,
080            TokenTypes.LITERAL_SYNCHRONIZED,
081            TokenTypes.LITERAL_TRY,
082            TokenTypes.LITERAL_CASE,
083            TokenTypes.LAMBDA,
084            TokenTypes.LITERAL_WHEN,
085        };
086    }
087
088    @Override
089    public int[] getAcceptableTokens() {
090        return new int[] {
091            TokenTypes.COMMA,
092            TokenTypes.SEMI,
093            TokenTypes.TYPECAST,
094            TokenTypes.LITERAL_IF,
095            TokenTypes.LITERAL_ELSE,
096            TokenTypes.LITERAL_WHILE,
097            TokenTypes.LITERAL_DO,
098            TokenTypes.LITERAL_FOR,
099            TokenTypes.LITERAL_FINALLY,
100            TokenTypes.LITERAL_RETURN,
101            TokenTypes.LITERAL_YIELD,
102            TokenTypes.LITERAL_CATCH,
103            TokenTypes.DO_WHILE,
104            TokenTypes.ELLIPSIS,
105            TokenTypes.LITERAL_SWITCH,
106            TokenTypes.LITERAL_SYNCHRONIZED,
107            TokenTypes.LITERAL_TRY,
108            TokenTypes.LITERAL_CASE,
109            TokenTypes.LAMBDA,
110            TokenTypes.LITERAL_WHEN,
111            TokenTypes.ANNOTATIONS,
112            TokenTypes.SINGLE_LINE_COMMENT,
113        };
114    }
115
116    @Override
117    public int[] getRequiredTokens() {
118        return CommonUtil.EMPTY_INT_ARRAY;
119    }
120
121    @Override
122    public boolean isCommentNodesRequired() {
123        return true;
124    }
125
126    @Override
127    public void visitToken(DetailAST ast) {
128        final int type = ast.getType();
129        if (type == TokenTypes.TYPECAST) {
130            final DetailAST targetAST = ast.findFirstToken(TokenTypes.RPAREN);
131            final int[] line = getLineCodePoints(targetAST.getLineNo() - 1);
132            if (!isFollowedByWhitespace(targetAST, line)) {
133                log(targetAST, MSG_WS_TYPECAST);
134            }
135        }
136        else if (type == TokenTypes.ANNOTATIONS) {
137            if (ast.getFirstChild() != null) {
138                DetailAST targetAST = ast.getFirstChild().getLastChild();
139                if (targetAST.getType() == TokenTypes.DOT) {
140                    targetAST = targetAST.getLastChild();
141                }
142                final int[] line = getLineCodePoints(targetAST.getLineNo() - 1);
143                if (!isFollowedByWhitespace(targetAST, line)) {
144                    final Object[] message = {targetAST.getText()};
145                    log(targetAST, MSG_WS_NOT_FOLLOWED, message);
146                }
147            }
148        }
149        else if (type == TokenTypes.SINGLE_LINE_COMMENT) {
150            if (!isCommentFollowedByWhitespace(ast)) {
151                log(ast, MSG_WS_NOT_FOLLOWED, ast.getText());
152            }
153        }
154        else {
155            final int[] line = getLineCodePoints(ast.getLineNo() - 1);
156            if (!isFollowedByWhitespace(ast, line)) {
157                final Object[] message = {ast.getText()};
158                log(ast, MSG_WS_NOT_FOLLOWED, message);
159            }
160        }
161    }
162
163    /**
164     * Checks whether a single-line comment is followed by whitespace.
165     *
166     * @param ast AST token representing the single-line comment.
167     * @return {@code true} if the comment content is empty or is
168     *         followed by whitespace after any leading slashes.
169     */
170    private static boolean isCommentFollowedByWhitespace(DetailAST ast) {
171        final DetailAST commentContent = ast.findFirstToken(TokenTypes.COMMENT_CONTENT);
172        final String commentText = commentContent.getText();
173        int index = 0;
174        while (commentText.charAt(index) == '/') {
175            index++;
176        }
177        final int codePoint = commentText.codePointAt(index);
178        return Character.isWhitespace(codePoint);
179    }
180
181    /**
182     * Checks whether token is followed by a whitespace.
183     *
184     * @param targetAST Ast token.
185     * @param line Unicode code points array of line associated with the ast token.
186     * @return true if ast token is followed by a whitespace.
187     */
188    private static boolean isFollowedByWhitespace(DetailAST targetAST, int... line) {
189        final int after =
190            targetAST.getColumnNo() + targetAST.getText().length();
191        boolean followedByWhitespace = true;
192
193        if (after < line.length) {
194            final int codePoint = line[after];
195
196            followedByWhitespace = codePoint == ';'
197                || codePoint == ')'
198                || Character.isWhitespace(codePoint);
199        }
200        return followedByWhitespace;
201    }
202
203}