001///////////////////////////////////////////////////////////////////////////////////////////////
002// checkstyle: Checks Java source code and other text files for adherence to a set of rules.
003// Copyright (C) 2001-2023 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 * <p>
033 * Checks for missing package definition Javadoc comments in package-info.java files.
034 * </p>
035 * <p>
036 * Rationale: description and other related documentation for a package can be written up
037 * in the package-info.java file and it gets used in the production of the Javadocs.
038 * See <a
039 * href="https://docs.oracle.com/javase/8/docs/technotes/tools/windows/javadoc.html#packagecomment"
040 * >link</a> for more info.
041 * </p>
042 * <p>
043 * This check specifically only validates package definitions. It will not validate any methods or
044 * interfaces declared in the package-info.java file.
045 * </p>
046 * <p>
047 * To configure the check:
048 * </p>
049 * <pre>
050 * &lt;module name="MissingJavadocPackage"/&gt;
051 * </pre>
052 * <p>Example:</p>
053 * <pre>
054 * /**
055 * * Provides API classes
056 * *&#47;
057 * package com.checkstyle.api; // no violation
058 * /*
059 * * Block comment is not a javadoc
060 * *&#47;
061 * package com.checkstyle.api; // violation
062 * </pre>
063 * <p>
064 * Parent is {@code com.puppycrawl.tools.checkstyle.TreeWalker}
065 * </p>
066 * <p>
067 * Violation Message Keys:
068 * </p>
069 * <ul>
070 * <li>
071 * {@code package.javadoc.missing}
072 * </li>
073 * </ul>
074 *
075 * @since 8.22
076 */
077@StatelessCheck
078public class MissingJavadocPackageCheck extends AbstractCheck {
079
080    /**
081     * A key is pointing to the warning message text in "messages.properties"
082     * file.
083     */
084    public static final String MSG_PKG_JAVADOC_MISSING = "package.javadoc.missing";
085
086    @Override
087    public int[] getDefaultTokens() {
088        return getRequiredTokens();
089    }
090
091    @Override
092    public int[] getAcceptableTokens() {
093        return getRequiredTokens();
094    }
095
096    @Override
097    public int[] getRequiredTokens() {
098        return new int[] {TokenTypes.PACKAGE_DEF};
099    }
100
101    @Override
102    public boolean isCommentNodesRequired() {
103        return true;
104    }
105
106    @Override
107    public void visitToken(DetailAST ast) {
108        if (CheckUtil.isPackageInfo(getFilePath()) && !hasJavadoc(ast)) {
109            log(ast, MSG_PKG_JAVADOC_MISSING);
110        }
111    }
112
113    /**
114     * Checks that there is javadoc before ast.
115     * Because of <a href="https://github.com/checkstyle/checkstyle/issues/4392">parser bug</a>
116     * parser can place javadoc comment either as previous sibling of package definition
117     * or (if there is annotation between package def and javadoc) inside package definition tree.
118     * So we should look for javadoc in both places.
119     *
120     * @param ast {@link TokenTypes#PACKAGE_DEF} token to check
121     * @return true if there is javadoc, false otherwise
122     */
123    private static boolean hasJavadoc(DetailAST ast) {
124        final boolean hasJavadocBefore = ast.getPreviousSibling() != null
125            && isJavadoc(ast.getPreviousSibling());
126        return hasJavadocBefore || hasJavadocAboveAnnotation(ast);
127    }
128
129    /**
130     * Checks javadoc existence in annotations list.
131     *
132     * @param ast package def
133     * @return true if there is a javadoc, false otherwise
134     */
135    private static boolean hasJavadocAboveAnnotation(DetailAST ast) {
136        final Optional<DetailAST> firstAnnotationChild = Optional.of(ast.getFirstChild())
137            .map(DetailAST::getFirstChild)
138            .map(DetailAST::getFirstChild);
139        boolean result = false;
140        if (firstAnnotationChild.isPresent()) {
141            for (DetailAST child = firstAnnotationChild.get(); child != null;
142                 child = child.getNextSibling()) {
143                if (isJavadoc(child)) {
144                    result = true;
145                    break;
146                }
147            }
148        }
149        return result;
150    }
151
152    /**
153     * Checks that ast is a javadoc comment.
154     *
155     * @param ast token to check
156     * @return true if ast is a javadoc comment, false otherwise
157     */
158    private static boolean isJavadoc(DetailAST ast) {
159        return ast.getType() == TokenTypes.BLOCK_COMMENT_BEGIN && JavadocUtil.isJavadocComment(ast);
160    }
161}