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.util.regex.Pattern;
023
024import com.puppycrawl.tools.checkstyle.StatelessCheck;
025import com.puppycrawl.tools.checkstyle.api.AbstractCheck;
026import com.puppycrawl.tools.checkstyle.api.DetailAST;
027import com.puppycrawl.tools.checkstyle.api.TokenTypes;
028
029/**
030 * <div>
031 * Checks for {@code TODO:} comments. Actually it is a generic
032 * <a href="https://docs.oracle.com/en/java/javase/17/docs/api/java.base/java/util/regex/Pattern.html">
033 * pattern</a> matcher on Java comments. To check for other patterns
034 * in Java comments, set the {@code format} property.
035 * </div>
036 *
037 * <p>
038 * Notes:
039 * Using {@code TODO:} comments is a great way to keep track of tasks that need to be done.
040 * Having them reported by Checkstyle makes it very hard to forget about them.
041 * </p>
042 *
043 * @since 3.0
044 */
045@StatelessCheck
046public class TodoCommentCheck extends AbstractCheck {
047
048    /**
049     * A key is pointing to the warning message text in "messages.properties" file.
050     */
051    public static final String MSG_KEY = "todo.match";
052
053    /**
054     * Specify pattern to match comments against.
055     */
056    private Pattern format = Pattern.compile("TODO:");
057
058    /**
059     * Creates a new {@code TodoCommentCheck} instance.
060     */
061    public TodoCommentCheck() {
062        // no code by default
063    }
064
065    @Override
066    public boolean isCommentNodesRequired() {
067        return true;
068    }
069
070    /**
071     * Setter to specify pattern to match comments against.
072     *
073     * @param pattern
074     *        pattern of 'todo' comment.
075     * @since 3.0
076     */
077    public void setFormat(Pattern pattern) {
078        format = pattern;
079    }
080
081    @Override
082    public int[] getDefaultTokens() {
083        return getRequiredTokens();
084    }
085
086    @Override
087    public int[] getAcceptableTokens() {
088        return getRequiredTokens();
089    }
090
091    @Override
092    public int[] getRequiredTokens() {
093        return new int[] {TokenTypes.COMMENT_CONTENT };
094    }
095
096    @Override
097    public void visitToken(DetailAST ast) {
098        final String[] lines = ast.getText().split("\n", -1);
099
100        for (String line : lines) {
101            if (format.matcher(line).find()) {
102                log(ast, MSG_KEY, format.pattern());
103            }
104        }
105    }
106
107}