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.annotation;
021
022import java.util.Objects;
023import java.util.Optional;
024import java.util.regex.Pattern;
025import java.util.stream.Stream;
026
027import com.puppycrawl.tools.checkstyle.StatelessCheck;
028import com.puppycrawl.tools.checkstyle.api.AbstractCheck;
029import com.puppycrawl.tools.checkstyle.api.DetailAST;
030import com.puppycrawl.tools.checkstyle.api.TokenTypes;
031import com.puppycrawl.tools.checkstyle.checks.javadoc.JavadocTagInfo;
032import com.puppycrawl.tools.checkstyle.utils.AnnotationUtil;
033import com.puppycrawl.tools.checkstyle.utils.CommonUtil;
034import com.puppycrawl.tools.checkstyle.utils.JavadocUtil;
035
036/**
037 * <div>
038 * Verifies that the {@code @Override} annotation is present
039 * when the {@code @inheritDoc} javadoc tag is present.
040 * </div>
041 *
042 * <p>
043 * Rationale: The &#64;Override annotation helps
044 * compiler tools ensure that an override is actually occurring.  It is
045 * quite easy to accidentally overload a method or hide a static method
046 * and using the &#64;Override annotation points out these problems.
047 * </p>
048 *
049 * <p>
050 * This check will log a violation if using the &#64;inheritDoc tag on a method that
051 * is not valid (ex: private, or static method).
052 * </p>
053 *
054 * <p>
055 * There is a slight difference between the &#64;Override annotation in Java 5 versus
056 * Java 6 and above. In Java 5, any method overridden from an interface cannot
057 * be annotated with &#64;Override. In Java 6 this behavior is allowed.
058 * </p>
059 *
060 * <p>
061 * As a result of the aforementioned difference between Java 5 and Java 6, a
062 * property called {@code javaFiveCompatibility} is available. This
063 * property will only check classes, interfaces, etc. that do not contain the
064 * extends or implements keyword or are not anonymous classes. This means it
065 * only checks methods overridden from {@code java.lang.Object}.
066 * <b>Java 5 Compatibility mode severely limits this check. It is recommended to
067 * only use it on Java 5 source.</b>
068 * </p>
069 * <ul>
070 * <li>
071 * Property {@code javaFiveCompatibility} - Enable java 5 compatibility mode.
072 * Type is {@code boolean}.
073 * Default value is {@code false}.
074 * </li>
075 * </ul>
076 *
077 * <p>
078 * Parent is {@code com.puppycrawl.tools.checkstyle.TreeWalker}
079 * </p>
080 *
081 * <p>
082 * Violation Message Keys:
083 * </p>
084 * <ul>
085 * <li>
086 * {@code annotation.missing.override}
087 * </li>
088 * <li>
089 * {@code tag.not.valid.on}
090 * </li>
091 * </ul>
092 *
093 * @since 5.0
094 */
095@StatelessCheck
096public final class MissingOverrideCheck extends AbstractCheck {
097
098    /**
099     * A key is pointing to the warning message text in "messages.properties"
100     * file.
101     */
102    public static final String MSG_KEY_TAG_NOT_VALID_ON = "tag.not.valid.on";
103
104    /**
105     * A key is pointing to the warning message text in "messages.properties"
106     * file.
107     */
108    public static final String MSG_KEY_ANNOTATION_MISSING_OVERRIDE =
109        "annotation.missing.override";
110
111    /** Compiled regexp to match Javadoc tags with no argument and {}. */
112    private static final Pattern MATCH_INHERIT_DOC =
113            CommonUtil.createPattern("\\{\\s*@(inheritDoc)\\s*\\}");
114
115    /**
116     * Enable java 5 compatibility mode.
117     */
118    private boolean javaFiveCompatibility;
119
120    /**
121     * Setter to enable java 5 compatibility mode.
122     *
123     * @param compatibility compatibility or not
124     * @since 5.0
125     */
126    public void setJavaFiveCompatibility(final boolean compatibility) {
127        javaFiveCompatibility = compatibility;
128    }
129
130    @Override
131    public int[] getDefaultTokens() {
132        return getRequiredTokens();
133    }
134
135    @Override
136    public int[] getAcceptableTokens() {
137        return getRequiredTokens();
138    }
139
140    @Override
141    public boolean isCommentNodesRequired() {
142        return true;
143    }
144
145    @Override
146    public int[] getRequiredTokens() {
147        return new int[]
148        {TokenTypes.METHOD_DEF, };
149    }
150
151    @Override
152    public void visitToken(final DetailAST ast) {
153        final boolean containsTag = containsInheritDocTag(ast);
154        if (containsTag && !JavadocTagInfo.INHERIT_DOC.isValidOn(ast)) {
155            log(ast, MSG_KEY_TAG_NOT_VALID_ON,
156                JavadocTagInfo.INHERIT_DOC.getText());
157        }
158        else {
159            boolean check = true;
160
161            if (javaFiveCompatibility) {
162                final DetailAST defOrNew = ast.getParent().getParent();
163
164                if (defOrNew.findFirstToken(TokenTypes.EXTENDS_CLAUSE) != null
165                    || defOrNew.findFirstToken(TokenTypes.IMPLEMENTS_CLAUSE) != null
166                    || defOrNew.getType() == TokenTypes.LITERAL_NEW) {
167                    check = false;
168                }
169            }
170
171            if (check
172                && containsTag
173                && !AnnotationUtil.hasOverrideAnnotation(ast)) {
174                log(ast, MSG_KEY_ANNOTATION_MISSING_OVERRIDE);
175            }
176        }
177    }
178
179    /**
180     * Checks to see if the ast contains a inheritDoc tag.
181     *
182     * @param ast method AST node
183     * @return true if contains the tag
184     */
185    private static boolean containsInheritDocTag(DetailAST ast) {
186        final DetailAST modifiers = ast.getFirstChild();
187        final DetailAST startNode;
188        if (modifiers.hasChildren()) {
189            startNode = Optional.ofNullable(ast.getFirstChild()
190                    .findFirstToken(TokenTypes.ANNOTATION))
191                .orElse(modifiers);
192        }
193        else {
194            startNode = ast.findFirstToken(TokenTypes.TYPE);
195        }
196        final Optional<String> javadoc =
197            Stream.iterate(startNode.getLastChild(), Objects::nonNull,
198                    DetailAST::getPreviousSibling)
199            .filter(node -> node.getType() == TokenTypes.BLOCK_COMMENT_BEGIN)
200            .map(DetailAST::getFirstChild)
201            .map(DetailAST::getText)
202            .filter(JavadocUtil::isJavadocComment)
203            .findFirst();
204        return javadoc.isPresent()
205                && MATCH_INHERIT_DOC.matcher(javadoc.orElseThrow()).find();
206    }
207
208}