001///////////////////////////////////////////////////////////////////////////////////////////////
002// checkstyle: Checks Java source code and other text files for adherence to a set of rules.
003// Copyright (C) 2001-2025 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 * Since version 7.3
047 * <a href="https://checkstyle.org/apidocs/com/puppycrawl/tools/checkstyle/api/JavadocTokenTypes.html#PARAM_LITERAL">
048 * PARAM_LITERAL</a>,
049 * <a href="https://checkstyle.org/apidocs/com/puppycrawl/tools/checkstyle/api/JavadocTokenTypes.html#RETURN_LITERAL">
050 * RETURN_LITERAL</a>,
051 * <a href="https://checkstyle.org/apidocs/com/puppycrawl/tools/checkstyle/api/JavadocTokenTypes.html#THROWS_LITERAL">
052 * THROWS_LITERAL</a>,
053 * <a href="https://checkstyle.org/apidocs/com/puppycrawl/tools/checkstyle/api/JavadocTokenTypes.html#EXCEPTION_LITERAL">
054 * EXCEPTION_LITERAL</a>,
055 * <a href="https://checkstyle.org/apidocs/com/puppycrawl/tools/checkstyle/api/JavadocTokenTypes.html#DEPRECATED_LITERAL">
056 * DEPRECATED_LITERAL</a>.
057 * </li>
058 * </ul>
059 *
060 * <p>
061 * Parent is {@code com.puppycrawl.tools.checkstyle.TreeWalker}
062 * </p>
063 *
064 * <p>
065 * Violation Message Keys:
066 * </p>
067 * <ul>
068 * <li>
069 * {@code javadoc.missed.html.close}
070 * </li>
071 * <li>
072 * {@code javadoc.parse.rule.error}
073 * </li>
074 * <li>
075 * {@code javadoc.unclosedHtml}
076 * </li>
077 * <li>
078 * {@code javadoc.wrong.singleton.html.tag}
079 * </li>
080 * <li>
081 * {@code non.empty.atclause}
082 * </li>
083 * </ul>
084 *
085 * @since 6.0
086 */
087@StatelessCheck
088public class NonEmptyAtclauseDescriptionCheck extends AbstractJavadocCheck {
089
090    /**
091     * A key is pointing to the warning message text in "messages.properties"
092     * file.
093     */
094    public static final String MSG_KEY = "non.empty.atclause";
095
096    @Override
097    public int[] getDefaultJavadocTokens() {
098        return new int[] {
099            JavadocTokenTypes.PARAM_LITERAL,
100            JavadocTokenTypes.RETURN_LITERAL,
101            JavadocTokenTypes.THROWS_LITERAL,
102            JavadocTokenTypes.EXCEPTION_LITERAL,
103            JavadocTokenTypes.DEPRECATED_LITERAL,
104        };
105    }
106
107    @Override
108    public void visitJavadocToken(DetailNode ast) {
109        if (isEmptyTag(ast.getParent())) {
110            log(ast.getLineNumber(), MSG_KEY);
111        }
112    }
113
114    /**
115     * Tests if block tag is empty.
116     *
117     * @param tagNode block tag.
118     * @return true, if block tag is empty.
119     */
120    private static boolean isEmptyTag(DetailNode tagNode) {
121        final DetailNode tagDescription =
122                JavadocUtil.findFirstToken(tagNode, JavadocTokenTypes.DESCRIPTION);
123        return tagDescription == null
124            || hasOnlyEmptyText(tagDescription);
125    }
126
127    /**
128     * Tests if description node is empty (has only new lines and blank strings).
129     *
130     * @param description description node.
131     * @return true, if description node has only new lines and blank strings.
132     */
133    private static boolean hasOnlyEmptyText(DetailNode description) {
134        boolean result = true;
135        for (DetailNode child : description.getChildren()) {
136            if (child.getType() != JavadocTokenTypes.LEADING_ASTERISK
137                    && !CommonUtil.isBlank(child.getText())) {
138                result = false;
139                break;
140            }
141        }
142        return result;
143    }
144
145}