001///////////////////////////////////////////////////////////////////////////////////////////////
002// checkstyle: Checks Java source code and other text files for adherence to a set of rules.
003// Copyright (C) 2001-2022 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 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 * To configure the check:
044 * </p>
045 * <pre>
046 * &lt;module name="MissingJavadocPackage"/&gt;
047 * </pre>
048 * <p>Example:</p>
049 * <pre>
050 * /**
051 * * Provides API classes
052 * *&#47;
053 * package com.checkstyle.api; // no violation
054 * /*
055 * * Block comment is not a javadoc
056 * *&#47;
057 * package com.checkstyle.api; // violation
058 * </pre>
059 * <p>
060 * Parent is {@code com.puppycrawl.tools.checkstyle.TreeWalker}
061 * </p>
062 * <p>
063 * Violation Message Keys:
064 * </p>
065 * <ul>
066 * <li>
067 * {@code package.javadoc.missing}
068 * </li>
069 * </ul>
070 *
071 * @since 8.22
072 */
073@StatelessCheck
074public class MissingJavadocPackageCheck extends AbstractCheck {
075
076    /**
077     * A key is pointing to the warning message text in "messages.properties"
078     * file.
079     */
080    public static final String MSG_PKG_JAVADOC_MISSING = "package.javadoc.missing";
081
082    @Override
083    public int[] getDefaultTokens() {
084        return getRequiredTokens();
085    }
086
087    @Override
088    public int[] getAcceptableTokens() {
089        return getRequiredTokens();
090    }
091
092    @Override
093    public int[] getRequiredTokens() {
094        return new int[] {TokenTypes.PACKAGE_DEF};
095    }
096
097    @Override
098    public boolean isCommentNodesRequired() {
099        return true;
100    }
101
102    @Override
103    public void visitToken(DetailAST ast) {
104        if (CheckUtil.isPackageInfo(getFilePath()) && !hasJavadoc(ast)) {
105            log(ast, MSG_PKG_JAVADOC_MISSING);
106        }
107    }
108
109    /**
110     * Checks that there is javadoc before ast.
111     * Because of <a href="https://github.com/checkstyle/checkstyle/issues/4392">parser bug</a>
112     * parser can place javadoc comment either as previous sibling of package definition
113     * or (if there is annotation between package def and javadoc) inside package definition tree.
114     * So we should look for javadoc in both places.
115     *
116     * @param ast {@link TokenTypes#PACKAGE_DEF} token to check
117     * @return true if there is javadoc, false otherwise
118     */
119    private static boolean hasJavadoc(DetailAST ast) {
120        final boolean hasJavadocBefore = ast.getPreviousSibling() != null
121            && isJavadoc(ast.getPreviousSibling());
122        return hasJavadocBefore || hasJavadocAboveAnnotation(ast);
123    }
124
125    /**
126     * Checks javadoc existence in annotations list.
127     *
128     * @param ast package def
129     * @return true if there is a javadoc, false otherwise
130     */
131    private static boolean hasJavadocAboveAnnotation(DetailAST ast) {
132        final Optional<DetailAST> firstAnnotationChild = Optional.of(ast.getFirstChild())
133            .map(DetailAST::getFirstChild)
134            .map(DetailAST::getFirstChild);
135        boolean result = false;
136        if (firstAnnotationChild.isPresent()) {
137            for (DetailAST child = firstAnnotationChild.get(); child != null;
138                 child = child.getNextSibling()) {
139                if (isJavadoc(child)) {
140                    result = true;
141                    break;
142                }
143            }
144        }
145        return result;
146    }
147
148    /**
149     * Checks that ast is a javadoc comment.
150     *
151     * @param ast token to check
152     * @return true if ast is a javadoc comment, false otherwise
153     */
154    private static boolean isJavadoc(DetailAST ast) {
155        return ast.getType() == TokenTypes.BLOCK_COMMENT_BEGIN && JavadocUtil.isJavadocComment(ast);
156    }
157}