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