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.sizes;
021
022import java.util.Set;
023
024import com.puppycrawl.tools.checkstyle.StatelessCheck;
025import com.puppycrawl.tools.checkstyle.api.AbstractCheck;
026import com.puppycrawl.tools.checkstyle.api.DetailAST;
027import com.puppycrawl.tools.checkstyle.api.TokenTypes;
028import com.puppycrawl.tools.checkstyle.utils.AnnotationUtil;
029import com.puppycrawl.tools.checkstyle.utils.CommonUtil;
030
031/**
032 * <div>
033 * Checks the number of parameters of a method or constructor.
034 * </div>
035 *
036 * @since 3.0
037 */
038@StatelessCheck
039public class ParameterNumberCheck extends AbstractCheck {
040
041    /**
042     * A key is pointing to the warning message text in "messages.properties" file.
043     */
044    public static final String MSG_KEY = "maxParam";
045
046    /** Default maximum number of allowed parameters. */
047    private static final int DEFAULT_MAX_PARAMETERS = 7;
048
049    /** Specify the maximum number of parameters allowed. */
050    private int max = DEFAULT_MAX_PARAMETERS;
051
052    /** Ignore number of parameters for methods with {@code @Override} annotation. */
053    private boolean ignoreOverriddenMethods;
054
055    /**
056     * Ignore methods and constructors annotated with the specified annotation(s).
057     */
058    private Set<String> ignoreAnnotatedBy = Set.of();
059
060    /**
061     * Creates a new {@code ParameterNumberCheck} instance.
062     */
063    public ParameterNumberCheck() {
064        // no code by default
065    }
066
067    /**
068     * Setter to specify the maximum number of parameters allowed.
069     *
070     * @param max the max allowed parameters
071     * @since 3.0
072     */
073    public void setMax(int max) {
074        this.max = max;
075    }
076
077    /**
078     * Setter to ignore number of parameters for methods with {@code @Override} annotation.
079     *
080     * @param ignoreOverriddenMethods set ignore overridden methods
081     * @since 6.2
082     */
083    public void setIgnoreOverriddenMethods(boolean ignoreOverriddenMethods) {
084        this.ignoreOverriddenMethods = ignoreOverriddenMethods;
085    }
086
087    /**
088     * Setter to ignore methods and constructors annotated with the specified annotation(s).
089     *
090     * @param annotationNames specified annotation(s)
091     * @since 10.15.0
092     */
093    public void setIgnoreAnnotatedBy(String... annotationNames) {
094        ignoreAnnotatedBy = Set.of(annotationNames);
095    }
096
097    @Override
098    public int[] getDefaultTokens() {
099        return getAcceptableTokens();
100    }
101
102    @Override
103    public int[] getAcceptableTokens() {
104        return new int[] {TokenTypes.METHOD_DEF, TokenTypes.CTOR_DEF};
105    }
106
107    @Override
108    public int[] getRequiredTokens() {
109        return CommonUtil.EMPTY_INT_ARRAY;
110    }
111
112    @Override
113    public void visitToken(DetailAST ast) {
114        final DetailAST params = ast.findFirstToken(TokenTypes.PARAMETERS);
115        final int count = params.getChildCount(TokenTypes.PARAMETER_DEF);
116        if (count > max && !shouldIgnoreNumberOfParameters(ast)) {
117            final DetailAST name = ast.findFirstToken(TokenTypes.IDENT);
118            log(name, MSG_KEY, max, count);
119        }
120    }
121
122    /**
123     * Determine whether to ignore number of parameters.
124     *
125     * @param ast the token to process
126     * @return true if number of parameters should be ignored.
127     */
128    private boolean shouldIgnoreNumberOfParameters(DetailAST ast) {
129        return isIgnoredOverriddenMethod(ast) || isAnnotatedByIgnoredAnnotations(ast);
130    }
131
132    /**
133     * Checks if method is overridden and should be ignored.
134     *
135     * @param ast method definition to check
136     * @return true if method is overridden and should be ignored.
137     */
138    private boolean isIgnoredOverriddenMethod(DetailAST ast) {
139        return ignoreOverriddenMethods && AnnotationUtil.hasOverrideAnnotation(ast);
140    }
141
142    /**
143     * Checks if method or constructor is annotated by ignored annotation(s).
144     *
145     * @param ast method or constructor definition to check
146     * @return true if annotated by ignored annotation(s).
147     */
148    private boolean isAnnotatedByIgnoredAnnotations(DetailAST ast) {
149        return AnnotationUtil.containsAnnotation(ast, ignoreAnnotatedBy);
150    }
151
152}