001////////////////////////////////////////////////////////////////////////////////
002// checkstyle: Checks Java source code for adherence to a set of rules.
003// Copyright (C) 2001-2020 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.sizes;
021
022import java.util.Arrays;
023import java.util.concurrent.atomic.AtomicInteger;
024
025import com.puppycrawl.tools.checkstyle.StatelessCheck;
026import com.puppycrawl.tools.checkstyle.api.AbstractCheck;
027import com.puppycrawl.tools.checkstyle.api.DetailAST;
028import com.puppycrawl.tools.checkstyle.api.TokenTypes;
029import com.puppycrawl.tools.checkstyle.checks.naming.AccessModifierOption;
030import com.puppycrawl.tools.checkstyle.utils.CheckUtil;
031import com.puppycrawl.tools.checkstyle.utils.TokenUtil;
032
033/**
034 * <p>
035 * Checks the number of record components in the
036 * <a href="https://docs.oracle.com/javase/specs/jls/se14/preview/specs/records-jls.html#jls-8.10.1">
037 * header</a> of a record definition.
038 * </p>
039 * <ul>
040 * <li>
041 * Property {@code max} - Specify the maximum number of components allowed in the header of a
042 * record definition.
043 * Type is {@code int}.
044 * Default value is {@code 8}.
045 * </li>
046 * <li>
047 * Property {@code accessModifiers} - Access modifiers of record definitions where
048 * the number of record components should be checked.
049 * Type is {@code com.puppycrawl.tools.checkstyle.checks.naming.AccessModifierOption[]}.
050 * Default value is {@code public, protected, package, private}.
051 * </li>
052 * </ul>
053 * <p>
054 * To configure the check:
055 * </p>
056 * <pre>
057 * &lt;module name="RecordComponentNumber"/&gt;
058 * </pre>
059 * <p>
060 * Java code example:
061 * </p>
062 * <pre>
063 * public record MyRecord1(int x, int y) { // ok, 2 components
064 *     ...
065 * }
066 *
067 * record MyRecord2(int x, int y, String str,
068 *                           Node node, Order order, Data data
069 *                           String location, Date date, Image image) { // violation, 9 components
070 *     ...
071 * }
072 * </pre>
073 * <p>
074 * To configure the check to allow 5 record components at all access modifier levels
075 * for record definitions:
076 * </p>
077 * <pre>
078 * &lt;module name="RecordComponentNumber"&gt;
079 *   &lt;property name="max" value="5"/&gt;
080 * &lt;/module&gt;
081 * </pre>
082 * <p>
083 * Java code example:
084 * </p>
085 * <pre>
086 * public record MyRecord1(int x, int y, String str) { // ok, 3 components
087 *     ...
088 * }
089 *
090 * public record MyRecord2(int x, int y, String str,
091 *                           Node node, Order order, Data data) { // violation, 6 components
092 *     ...
093 * }
094 * </pre>
095 * <p>
096 * To configure the check to allow 10 record components for a public record definition,
097 * but 3 for private record definitions:
098 * </p>
099 * <pre>
100 * &lt;module name="RecordComponentNumber"&gt;
101 *   &lt;property name="max" value="3"/&gt;
102 *   &lt;property name="accessModifiers" value="private"/&gt;
103 * &lt;/module&gt;
104 * &lt;module name="RecordComponentNumber"&gt;
105 *   &lt;property name="max" value="10"/&gt;
106 *   &lt;property name="accessModifiers" value="public"/&gt;
107 * &lt;/module&gt;
108 * </pre>
109 * <p>
110 * Java code example:
111 * </p>
112 * <pre>
113 * public record MyRecord1(int x, int y, String str) { // ok, public record definition allowed 10
114 *     ...
115 * }
116 *
117 * private record MyRecord2(int x, int y, String str, Node node) { // violation
118 *     ...                                // private record definition allowed 3 components
119 * }
120 * </pre>
121 * <p>
122 * Parent is {@code com.puppycrawl.tools.checkstyle.TreeWalker}
123 * </p>
124 * <p>
125 * Violation Message Keys:
126 * </p>
127 * <ul>
128 * <li>
129 * {@code too.many.components}
130 * </li>
131 * </ul>
132 *
133 * @since 8.36
134 */
135@StatelessCheck
136public class RecordComponentNumberCheck extends AbstractCheck {
137
138    /**
139     * A key is pointing to the warning message text in "messages.properties"
140     * file.
141     */
142    public static final String MSG_KEY = "too.many.components";
143
144    /** Default maximum number of allowed components. */
145    private static final int DEFAULT_MAX_COMPONENTS = 8;
146
147    /** Specify the maximum number of components allowed in the header of a record definition. */
148    private int max = DEFAULT_MAX_COMPONENTS;
149
150    /**
151     * Access modifiers of record definitions where the number
152     * of record components should be checked.
153     */
154    private AccessModifierOption[] accessModifiers = {
155        AccessModifierOption.PUBLIC,
156        AccessModifierOption.PROTECTED,
157        AccessModifierOption.PACKAGE,
158        AccessModifierOption.PRIVATE,
159    };
160
161    /**
162     * Setter to specify the maximum number of components allowed in the header
163     * of a record definition.
164     *
165     * @param value the maximum allowed.
166     */
167    public void setMax(int value) {
168        max = value;
169    }
170
171    /**
172     * Setter to access modifiers of record definitions where the number of record
173     * components should be checked.
174     *
175     * @param accessModifiers access modifiers of record definitions which should be checked.
176     */
177    public void setAccessModifiers(AccessModifierOption... accessModifiers) {
178        this.accessModifiers =
179                Arrays.copyOf(accessModifiers, accessModifiers.length);
180    }
181
182    @Override
183    public int[] getDefaultTokens() {
184        return getAcceptableTokens();
185    }
186
187    @Override
188    public int[] getAcceptableTokens() {
189        return new int[] {
190            TokenTypes.RECORD_DEF,
191        };
192    }
193
194    @Override
195    public int[] getRequiredTokens() {
196        return getAcceptableTokens();
197    }
198
199    @Override
200    public void visitToken(DetailAST ast) {
201        final DetailAST modifiers =
202            ast.findFirstToken(TokenTypes.MODIFIERS);
203        final AccessModifierOption accessModifier =
204            CheckUtil.getAccessModifierFromModifiersToken(modifiers);
205
206        if (matchAccessModifiers(accessModifier)) {
207            final DetailAST recordComponents =
208                ast.findFirstToken(TokenTypes.RECORD_COMPONENTS);
209            final int componentCount = countComponents(recordComponents);
210
211            if (componentCount > max) {
212                log(ast, MSG_KEY, componentCount, max);
213            }
214        }
215    }
216
217    /**
218     * Method to count the number of record components in this record definition.
219     *
220     * @param recordComponents the ast to check
221     * @return the number of record components in this record definition
222     */
223    private static int countComponents(DetailAST recordComponents) {
224        final AtomicInteger count = new AtomicInteger(0);
225        TokenUtil.forEachChild(recordComponents,
226            TokenTypes.RECORD_COMPONENT_DEF,
227            node -> count.getAndIncrement());
228        return count.get();
229    }
230
231    /**
232     * Checks whether a record definition has the correct access modifier to be checked.
233     *
234     * @param accessModifier the access modifier of the record definition.
235     * @return whether the record definition matches the expected access modifier.
236     */
237    private boolean matchAccessModifiers(final AccessModifierOption accessModifier) {
238        return Arrays.stream(accessModifiers)
239                .anyMatch(modifier -> modifier == accessModifier);
240    }
241}