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 com.puppycrawl.tools.checkstyle.StatelessCheck;
023import com.puppycrawl.tools.checkstyle.api.DetailNode;
024import com.puppycrawl.tools.checkstyle.api.JavadocTokenTypes;
025import com.puppycrawl.tools.checkstyle.utils.CommonUtil;
026import com.puppycrawl.tools.checkstyle.utils.JavadocUtil;
027
028/**
029 * <div>
030 * Checks that the block tag is followed by description.
031 * </div>
032 *
033 * <ul>
034 * <li>
035 * Property {@code violateExecutionOnNonTightHtml} - Control when to print violations
036 * if the Javadoc being examined by this check violates the tight html rules defined at
037 * <a href="https://checkstyle.org/writingjavadocchecks.html#Tight-HTML_rules">Tight-HTML Rules</a>.
038 * Type is {@code boolean}.
039 * Default value is {@code false}.
040 * </li>
041 * <li>
042 * Property {@code javadocTokens} - javadoc tokens to check
043 * Type is {@code java.lang.String[]}.
044 * Validation type is {@code tokenSet}.
045 * Default value is
046 * <a href="https://checkstyle.org/apidocs/com/puppycrawl/tools/checkstyle/api/JavadocTokenTypes.html#PARAM_LITERAL">
047 * PARAM_LITERAL</a>,
048 * <a href="https://checkstyle.org/apidocs/com/puppycrawl/tools/checkstyle/api/JavadocTokenTypes.html#RETURN_LITERAL">
049 * RETURN_LITERAL</a>,
050 * <a href="https://checkstyle.org/apidocs/com/puppycrawl/tools/checkstyle/api/JavadocTokenTypes.html#THROWS_LITERAL">
051 * THROWS_LITERAL</a>,
052 * <a href="https://checkstyle.org/apidocs/com/puppycrawl/tools/checkstyle/api/JavadocTokenTypes.html#EXCEPTION_LITERAL">
053 * EXCEPTION_LITERAL</a>,
054 * <a href="https://checkstyle.org/apidocs/com/puppycrawl/tools/checkstyle/api/JavadocTokenTypes.html#DEPRECATED_LITERAL">
055 * DEPRECATED_LITERAL</a>.
056 * </li>
057 * </ul>
058 *
059 * <p>
060 * Parent is {@code com.puppycrawl.tools.checkstyle.TreeWalker}
061 * </p>
062 *
063 * <p>
064 * Violation Message Keys:
065 * </p>
066 * <ul>
067 * <li>
068 * {@code javadoc.missed.html.close}
069 * </li>
070 * <li>
071 * {@code javadoc.parse.rule.error}
072 * </li>
073 * <li>
074 * {@code javadoc.unclosedHtml}
075 * </li>
076 * <li>
077 * {@code javadoc.wrong.singleton.html.tag}
078 * </li>
079 * <li>
080 * {@code non.empty.atclause}
081 * </li>
082 * </ul>
083 *
084 * @since 6.0
085 */
086@StatelessCheck
087public class NonEmptyAtclauseDescriptionCheck extends AbstractJavadocCheck {
088
089    /**
090     * A key is pointing to the warning message text in "messages.properties"
091     * file.
092     */
093    public static final String MSG_KEY = "non.empty.atclause";
094
095    @Override
096    public int[] getDefaultJavadocTokens() {
097        return new int[] {
098            JavadocTokenTypes.PARAM_LITERAL,
099            JavadocTokenTypes.RETURN_LITERAL,
100            JavadocTokenTypes.THROWS_LITERAL,
101            JavadocTokenTypes.EXCEPTION_LITERAL,
102            JavadocTokenTypes.DEPRECATED_LITERAL,
103        };
104    }
105
106    @Override
107    public void visitJavadocToken(DetailNode ast) {
108        if (isEmptyTag(ast.getParent())) {
109            log(ast.getLineNumber(), MSG_KEY);
110        }
111    }
112
113    /**
114     * Tests if block tag is empty.
115     *
116     * @param tagNode block tag.
117     * @return true, if block tag is empty.
118     */
119    private static boolean isEmptyTag(DetailNode tagNode) {
120        final DetailNode tagDescription =
121                JavadocUtil.findFirstToken(tagNode, JavadocTokenTypes.DESCRIPTION);
122        return tagDescription == null
123            || hasOnlyEmptyText(tagDescription);
124    }
125
126    /**
127     * Tests if description node is empty (has only new lines and blank strings).
128     *
129     * @param description description node.
130     * @return true, if description node has only new lines and blank strings.
131     */
132    private static boolean hasOnlyEmptyText(DetailNode description) {
133        boolean result = true;
134        for (DetailNode child : description.getChildren()) {
135            if (child.getType() != JavadocTokenTypes.LEADING_ASTERISK
136                    && !CommonUtil.isBlank(child.getText())) {
137                result = false;
138                break;
139            }
140        }
141        return result;
142    }
143
144}