001///////////////////////////////////////////////////////////////////////////////////////////////
002// checkstyle: Checks Java source code and other text files for adherence to a set of rules.
003// Copyright (C) 2001-2024 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.javadoc;
021
022import java.util.Optional;
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;
028import com.puppycrawl.tools.checkstyle.utils.CheckUtil;
029import com.puppycrawl.tools.checkstyle.utils.JavadocUtil;
030
031/**
032 * <div>
033 * Checks for missing package definition Javadoc comments in package-info.java files.
034 * </div>
035 *
036 * <p>
037 * Rationale: description and other related documentation for a package can be written up
038 * in the package-info.java file and it gets used in the production of the Javadocs.
039 * See <a
040 * href="https://docs.oracle.com/javase/8/docs/technotes/tools/windows/javadoc.html#packagecomment"
041 * >link</a> for more info.
042 * </p>
043 *
044 * <p>
045 * This check specifically only validates package definitions. It will not validate any methods or
046 * interfaces declared in the package-info.java file.
047 * </p>
048 *
049 * <p>
050 * Parent is {@code com.puppycrawl.tools.checkstyle.TreeWalker}
051 * </p>
052 *
053 * <p>
054 * Violation Message Keys:
055 * </p>
056 * <ul>
057 * <li>
058 * {@code package.javadoc.missing}
059 * </li>
060 * </ul>
061 *
062 * @since 8.22
063 */
064@StatelessCheck
065public class MissingJavadocPackageCheck extends AbstractCheck {
066
067    /**
068     * A key is pointing to the warning message text in "messages.properties"
069     * file.
070     */
071    public static final String MSG_PKG_JAVADOC_MISSING = "package.javadoc.missing";
072
073    @Override
074    public int[] getDefaultTokens() {
075        return getRequiredTokens();
076    }
077
078    @Override
079    public int[] getAcceptableTokens() {
080        return getRequiredTokens();
081    }
082
083    @Override
084    public int[] getRequiredTokens() {
085        return new int[] {TokenTypes.PACKAGE_DEF};
086    }
087
088    @Override
089    public boolean isCommentNodesRequired() {
090        return true;
091    }
092
093    @Override
094    public void visitToken(DetailAST ast) {
095        if (CheckUtil.isPackageInfo(getFilePath()) && !hasJavadoc(ast)) {
096            log(ast, MSG_PKG_JAVADOC_MISSING);
097        }
098    }
099
100    /**
101     * Checks that there is javadoc before ast.
102     * Because of <a href="https://github.com/checkstyle/checkstyle/issues/4392">parser bug</a>
103     * parser can place javadoc comment either as previous sibling of package definition
104     * or (if there is annotation between package def and javadoc) inside package definition tree.
105     * So we should look for javadoc in both places.
106     *
107     * @param ast {@link TokenTypes#PACKAGE_DEF} token to check
108     * @return true if there is javadoc, false otherwise
109     */
110    private static boolean hasJavadoc(DetailAST ast) {
111        final boolean hasJavadocBefore = ast.getPreviousSibling() != null
112            && isJavadoc(ast.getPreviousSibling());
113        return hasJavadocBefore || hasJavadocAboveAnnotation(ast);
114    }
115
116    /**
117     * Checks javadoc existence in annotations list.
118     *
119     * @param ast package def
120     * @return true if there is a javadoc, false otherwise
121     */
122    private static boolean hasJavadocAboveAnnotation(DetailAST ast) {
123        final Optional<DetailAST> firstAnnotationChild = Optional.of(ast.getFirstChild())
124            .map(DetailAST::getFirstChild)
125            .map(DetailAST::getFirstChild);
126        boolean result = false;
127        if (firstAnnotationChild.isPresent()) {
128            for (DetailAST child = firstAnnotationChild.orElseThrow(); child != null;
129                 child = child.getNextSibling()) {
130                if (isJavadoc(child)) {
131                    result = true;
132                    break;
133                }
134            }
135        }
136        return result;
137    }
138
139    /**
140     * Checks that ast is a javadoc comment.
141     *
142     * @param ast token to check
143     * @return true if ast is a javadoc comment, false otherwise
144     */
145    private static boolean isJavadoc(DetailAST ast) {
146        return ast.getType() == TokenTypes.BLOCK_COMMENT_BEGIN && JavadocUtil.isJavadocComment(ast);
147    }
148}