001////////////////////////////////////////////////////////////////////////////////
002// checkstyle: Checks Java source code for adherence to a set of rules.
003// Copyright (C) 2001-2021 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 * <p>
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 * </p>
034 * <ul>
035 * <li>
036 * Property {@code tokens} - tokens to check
037 * Type is {@code java.lang.String[]}.
038 * Validation type is {@code tokenSet}.
039 * Default value is:
040 * <a href="https://checkstyle.org/apidocs/com/puppycrawl/tools/checkstyle/api/TokenTypes.html#CLASS_DEF">
041 * CLASS_DEF</a>,
042 * <a href="https://checkstyle.org/apidocs/com/puppycrawl/tools/checkstyle/api/TokenTypes.html#INTERFACE_DEF">
043 * INTERFACE_DEF</a>,
044 * <a href="https://checkstyle.org/apidocs/com/puppycrawl/tools/checkstyle/api/TokenTypes.html#ENUM_DEF">
045 * ENUM_DEF</a>,
046 * <a href="https://checkstyle.org/apidocs/com/puppycrawl/tools/checkstyle/api/TokenTypes.html#METHOD_DEF">
047 * METHOD_DEF</a>,
048 * <a href="https://checkstyle.org/apidocs/com/puppycrawl/tools/checkstyle/api/TokenTypes.html#CTOR_DEF">
049 * CTOR_DEF</a>,
050 * <a href="https://checkstyle.org/apidocs/com/puppycrawl/tools/checkstyle/api/TokenTypes.html#VARIABLE_DEF">
051 * VARIABLE_DEF</a>,
052 * <a href="https://checkstyle.org/apidocs/com/puppycrawl/tools/checkstyle/api/TokenTypes.html#RECORD_DEF">
053 * RECORD_DEF</a>,
054 * <a href="https://checkstyle.org/apidocs/com/puppycrawl/tools/checkstyle/api/TokenTypes.html#COMPACT_CTOR_DEF">
055 * COMPACT_CTOR_DEF</a>.
056 * </li>
057 * </ul>
058 * <p>
059 * To configure the check:
060 * </p>
061 * <pre>
062 * &lt;module name=&quot;AnnotationOnSameLine&quot;/&gt;
063 * </pre>
064 * <p>
065 * Example:
066 * </p>
067 * <pre>
068 * class Foo {
069 *
070 *   &#64;SuppressWarnings("deprecation")  // violation, annotation should be on the same line
071 *   public Foo() {
072 *   }
073 *
074 *   &#64;SuppressWarnings("unchecked") public void fun2() {  // OK
075 *   }
076 *
077 * }
078 *
079 * &#64;SuppressWarnings("unchecked") class Bar extends Foo {  // OK
080 *
081 *   &#64;Deprecated public Bar() {  // OK
082 *   }
083 *
084 *   &#64;Override  // violation, annotation should be on the same line
085 *   public void fun1() {
086 *   }
087 *
088 *   &#64;Before &#64;Override public void fun2() {  // OK
089 *   }
090 *
091 *   &#64;SuppressWarnings("deprecation")  // violation, annotation should be on the same line
092 *   &#64;Before public void fun3() {
093 *   }
094 *
095 * }
096 * </pre>
097 * <p>
098 * To configure the check to check for annotations applied on
099 * interfaces, variables and constructors:
100 * </p>
101 * <pre>
102 * &lt;module name=&quot;AnnotationOnSameLine&quot;&gt;
103 *   &lt;property name=&quot;tokens&quot;
104 *       value=&quot;INTERFACE_DEF, VARIABLE_DEF, CTOR_DEF&quot;/&gt;
105 * &lt;/module&gt;
106 * </pre>
107 * <p>
108 * Example:
109 * </p>
110 * <pre>
111 * &#64;Deprecated interface Foo {  // OK
112 *
113 *   void doSomething();
114 *
115 * }
116 *
117 * class Bar implements Foo {
118 *
119 *   &#64;SuppressWarnings("deprecation")  // violation, annotation should be on the same line
120 *   public Bar() {
121 *   }
122 *
123 *   &#64;Override  // OK
124 *   public void doSomething() {
125 *   }
126 *
127 *   &#64;Nullable  // violation, annotation should be on the same line
128 *   String s;
129 *
130 * }
131 * </pre>
132 * <p>
133 * Parent is {@code com.puppycrawl.tools.checkstyle.TreeWalker}
134 * </p>
135 * <p>
136 * Violation Message Keys:
137 * </p>
138 * <ul>
139 * <li>
140 * {@code annotation.same.line}
141 * </li>
142 * </ul>
143 *
144 * @since 8.2
145 */
146@StatelessCheck
147public class AnnotationOnSameLineCheck extends AbstractCheck {
148
149    /** A key is pointing to the warning message text in "messages.properties" file. */
150    public static final String MSG_KEY_ANNOTATION_ON_SAME_LINE = "annotation.same.line";
151
152    @Override
153    public int[] getDefaultTokens() {
154        return new int[] {
155            TokenTypes.CLASS_DEF,
156            TokenTypes.INTERFACE_DEF,
157            TokenTypes.ENUM_DEF,
158            TokenTypes.METHOD_DEF,
159            TokenTypes.CTOR_DEF,
160            TokenTypes.VARIABLE_DEF,
161            TokenTypes.RECORD_DEF,
162            TokenTypes.COMPACT_CTOR_DEF,
163        };
164    }
165
166    @Override
167    public int[] getAcceptableTokens() {
168        return new int[] {
169            TokenTypes.CLASS_DEF,
170            TokenTypes.INTERFACE_DEF,
171            TokenTypes.ENUM_DEF,
172            TokenTypes.METHOD_DEF,
173            TokenTypes.CTOR_DEF,
174            TokenTypes.VARIABLE_DEF,
175            TokenTypes.PARAMETER_DEF,
176            TokenTypes.ANNOTATION_DEF,
177            TokenTypes.TYPECAST,
178            TokenTypes.LITERAL_THROWS,
179            TokenTypes.IMPLEMENTS_CLAUSE,
180            TokenTypes.TYPE_ARGUMENT,
181            TokenTypes.LITERAL_NEW,
182            TokenTypes.DOT,
183            TokenTypes.ANNOTATION_FIELD_DEF,
184            TokenTypes.RECORD_DEF,
185            TokenTypes.COMPACT_CTOR_DEF,
186        };
187    }
188
189    @Override
190    public int[] getRequiredTokens() {
191        return CommonUtil.EMPTY_INT_ARRAY;
192    }
193
194    @Override
195    public void visitToken(DetailAST ast) {
196        DetailAST nodeWithAnnotations = ast;
197        if (ast.getType() == TokenTypes.TYPECAST) {
198            nodeWithAnnotations = ast.findFirstToken(TokenTypes.TYPE);
199        }
200        DetailAST modifiersNode = nodeWithAnnotations.findFirstToken(TokenTypes.MODIFIERS);
201        if (modifiersNode == null) {
202            modifiersNode = nodeWithAnnotations.findFirstToken(TokenTypes.ANNOTATIONS);
203        }
204        if (modifiersNode != null) {
205            for (DetailAST annotationNode = modifiersNode.getFirstChild();
206                    annotationNode != null;
207                    annotationNode = annotationNode.getNextSibling()) {
208                if (annotationNode.getType() == TokenTypes.ANNOTATION
209                        && !TokenUtil.areOnSameLine(annotationNode, getNextNode(annotationNode))) {
210                    log(annotationNode, MSG_KEY_ANNOTATION_ON_SAME_LINE,
211                          getAnnotationName(annotationNode));
212                }
213            }
214        }
215    }
216
217    /**
218     * Finds next node of ast tree.
219     *
220     * @param node current node
221     * @return node that is next to given
222     */
223    private static DetailAST getNextNode(DetailAST node) {
224        DetailAST nextNode = node.getNextSibling();
225        if (nextNode == null) {
226            nextNode = node.getParent().getNextSibling();
227        }
228        return nextNode;
229    }
230
231    /**
232     * Returns the name of the given annotation.
233     *
234     * @param annotation annotation node.
235     * @return annotation name.
236     */
237    private static String getAnnotationName(DetailAST annotation) {
238        DetailAST identNode = annotation.findFirstToken(TokenTypes.IDENT);
239        if (identNode == null) {
240            identNode = annotation.findFirstToken(TokenTypes.DOT).getLastChild();
241        }
242        return identNode.getText();
243    }
244
245}