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
040    extends AbstractCheck {
041
042    /**
043     * A key is pointing to the warning message text in "messages.properties"
044     * file.
045     */
046    public static final String MSG_KEY = "maxParam";
047
048    /** Default maximum number of allowed parameters. */
049    private static final int DEFAULT_MAX_PARAMETERS = 7;
050
051    /** Specify the maximum number of parameters allowed. */
052    private int max = DEFAULT_MAX_PARAMETERS;
053
054    /** Ignore number of parameters for methods with {@code @Override} annotation. */
055    private boolean ignoreOverriddenMethods;
056
057    /**
058     * Ignore methods and constructors annotated with the specified annotation(s).
059     */
060    private Set<String> ignoreAnnotatedBy = Set.of();
061
062    /**
063     * Creates a new {@code ParameterNumberCheck} instance.
064     */
065    public ParameterNumberCheck() {
066        // no code by default
067    }
068
069    /**
070     * Setter to specify the maximum number of parameters allowed.
071     *
072     * @param max the max allowed parameters
073     * @since 3.0
074     */
075    public void setMax(int max) {
076        this.max = max;
077    }
078
079    /**
080     * Setter to ignore number of parameters for methods with {@code @Override} annotation.
081     *
082     * @param ignoreOverriddenMethods set ignore overridden methods
083     * @since 6.2
084     */
085    public void setIgnoreOverriddenMethods(boolean ignoreOverriddenMethods) {
086        this.ignoreOverriddenMethods = ignoreOverriddenMethods;
087    }
088
089    /**
090     * Setter to ignore methods and constructors annotated with the specified annotation(s).
091     *
092     * @param annotationNames specified annotation(s)
093     * @since 10.15.0
094     */
095    public void setIgnoreAnnotatedBy(String... annotationNames) {
096        ignoreAnnotatedBy = Set.of(annotationNames);
097    }
098
099    @Override
100    public int[] getDefaultTokens() {
101        return getAcceptableTokens();
102    }
103
104    @Override
105    public int[] getAcceptableTokens() {
106        return new int[] {TokenTypes.METHOD_DEF, TokenTypes.CTOR_DEF};
107    }
108
109    @Override
110    public int[] getRequiredTokens() {
111        return CommonUtil.EMPTY_INT_ARRAY;
112    }
113
114    @Override
115    public void visitToken(DetailAST ast) {
116        final DetailAST params = ast.findFirstToken(TokenTypes.PARAMETERS);
117        final int count = params.getChildCount(TokenTypes.PARAMETER_DEF);
118        if (count > max && !shouldIgnoreNumberOfParameters(ast)) {
119            final DetailAST name = ast.findFirstToken(TokenTypes.IDENT);
120            log(name, MSG_KEY, max, count);
121        }
122    }
123
124    /**
125     * Determine whether to ignore number of parameters.
126     *
127     * @param ast the token to process
128     * @return true if number of parameters should be ignored.
129     */
130    private boolean shouldIgnoreNumberOfParameters(DetailAST ast) {
131        return isIgnoredOverriddenMethod(ast) || isAnnotatedByIgnoredAnnotations(ast);
132    }
133
134    /**
135     * Checks if method is overridden and should be ignored.
136     *
137     * @param ast method definition to check
138     * @return true if method is overridden and should be ignored.
139     */
140    private boolean isIgnoredOverriddenMethod(DetailAST ast) {
141        return ignoreOverriddenMethods && AnnotationUtil.hasOverrideAnnotation(ast);
142    }
143
144    /**
145     * Checks if method or constructor is annotated by ignored annotation(s).
146     *
147     * @param ast method or constructor definition to check
148     * @return true if annotated by ignored annotation(s).
149     */
150    private boolean isAnnotatedByIgnoredAnnotations(DetailAST ast) {
151        return AnnotationUtil.containsAnnotation(ast, ignoreAnnotatedBy);
152    }
153
154}