001///////////////////////////////////////////////////////////////////////////////////////////////
002// checkstyle: Checks Java source code and other text files for adherence to a set of rules.
003// Copyright (C) 2001-2026 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 com.puppycrawl.tools.checkstyle.StatelessCheck;
023import com.puppycrawl.tools.checkstyle.api.AbstractCheck;
024import com.puppycrawl.tools.checkstyle.api.DetailAST;
025import com.puppycrawl.tools.checkstyle.api.TokenTypes;
026import com.puppycrawl.tools.checkstyle.utils.CommonUtil;
027import com.puppycrawl.tools.checkstyle.utils.TokenUtil;
028
029/**
030 * <div>
031 * Checks that annotations are located on the same line with their targets.
032 * Verifying with this check is not good practice, but it is using by some style guides.
033 * </div>
034 *
035 * @since 8.2
036 */
037@StatelessCheck
038public class AnnotationOnSameLineCheck extends AbstractCheck {
039
040    /** A key is pointing to the warning message text in "messages.properties" file. */
041    public static final String MSG_KEY_ANNOTATION_ON_SAME_LINE = "annotation.same.line";
042
043    /**
044     * Creates a new {@code AnnotationOnSameLineCheck} instance.
045     */
046    public AnnotationOnSameLineCheck() {
047        // no code by default
048    }
049
050    @Override
051    public int[] getDefaultTokens() {
052        return new int[] {
053            TokenTypes.CLASS_DEF,
054            TokenTypes.INTERFACE_DEF,
055            TokenTypes.ENUM_DEF,
056            TokenTypes.METHOD_DEF,
057            TokenTypes.CTOR_DEF,
058            TokenTypes.VARIABLE_DEF,
059            TokenTypes.RECORD_DEF,
060            TokenTypes.COMPACT_CTOR_DEF,
061        };
062    }
063
064    @Override
065    public int[] getAcceptableTokens() {
066        return new int[] {
067            TokenTypes.CLASS_DEF,
068            TokenTypes.INTERFACE_DEF,
069            TokenTypes.ENUM_DEF,
070            TokenTypes.METHOD_DEF,
071            TokenTypes.CTOR_DEF,
072            TokenTypes.VARIABLE_DEF,
073            TokenTypes.PARAMETER_DEF,
074            TokenTypes.ANNOTATION_DEF,
075            TokenTypes.TYPECAST,
076            TokenTypes.LITERAL_THROWS,
077            TokenTypes.IMPLEMENTS_CLAUSE,
078            TokenTypes.TYPE_ARGUMENT,
079            TokenTypes.LITERAL_NEW,
080            TokenTypes.DOT,
081            TokenTypes.ANNOTATION_FIELD_DEF,
082            TokenTypes.RECORD_DEF,
083            TokenTypes.COMPACT_CTOR_DEF,
084        };
085    }
086
087    @Override
088    public int[] getRequiredTokens() {
089        return CommonUtil.EMPTY_INT_ARRAY;
090    }
091
092    @Override
093    public void visitToken(DetailAST ast) {
094        DetailAST nodeWithAnnotations = ast;
095        if (ast.getType() == TokenTypes.TYPECAST) {
096            nodeWithAnnotations = ast.findFirstToken(TokenTypes.TYPE);
097        }
098        DetailAST modifiersNode = nodeWithAnnotations.findFirstToken(TokenTypes.MODIFIERS);
099        if (modifiersNode == null) {
100            modifiersNode = nodeWithAnnotations.findFirstToken(TokenTypes.ANNOTATIONS);
101        }
102        if (modifiersNode != null) {
103            for (DetailAST annotationNode = modifiersNode.getFirstChild();
104                    annotationNode != null;
105                    annotationNode = annotationNode.getNextSibling()) {
106                if (annotationNode.getType() == TokenTypes.ANNOTATION
107                        && !TokenUtil.areOnSameLine(annotationNode,
108                        modifiersNode.getNextSibling())) {
109                    log(annotationNode, MSG_KEY_ANNOTATION_ON_SAME_LINE,
110                          getAnnotationName(annotationNode));
111                }
112            }
113        }
114    }
115
116    /**
117     * Returns the name of the given annotation.
118     *
119     * @param annotation annotation node.
120     * @return annotation name.
121     */
122    private static String getAnnotationName(DetailAST annotation) {
123        DetailAST identNode = annotation.findFirstToken(TokenTypes.IDENT);
124        if (identNode == null) {
125            identNode = annotation.findFirstToken(TokenTypes.DOT).getLastChild();
126        }
127        return identNode.getText();
128    }
129
130}