code: ///////////////////////////////////////////////////////////////////////////////////////////////
  // checkstyle: Checks Java source code and other text files for adherence to a set of rules.
  // Copyright (C) 2001-2023 the original author or authors.
  //
  // This library is free software; you can redistribute it and/or
  // modify it under the terms of the GNU Lesser General Public
  // License as published by the Free Software Foundation; either
  // version 2.1 of the License, or (at your option) any later version.
  //
  // This library is distributed in the hope that it will be useful,
  // but WITHOUT ANY WARRANTY; without even the implied warranty of
  // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  // Lesser General Public License for more details.
  //
  // You should have received a copy of the GNU Lesser General Public
  // License along with this library; if not, write to the Free Software
  // Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  ///////////////////////////////////////////////////////////////////////////////////////////////
  
  package com.puppycrawl.tools.checkstyle.checks.sizes;
  
  import com.puppycrawl.tools.checkstyle.StatelessCheck;
  import com.puppycrawl.tools.checkstyle.api.AbstractCheck;
  import com.puppycrawl.tools.checkstyle.api.DetailAST;
  import com.puppycrawl.tools.checkstyle.api.TokenTypes;
  import com.puppycrawl.tools.checkstyle.utils.AnnotationUtil;
  import com.puppycrawl.tools.checkstyle.utils.CommonUtil;
  
  /**
   * <p>
   * Checks the number of parameters of a method or constructor.
   * </p>
   * <ul>
   * <li>
   * Property {@code max} - Specify the maximum number of parameters allowed.
   * Type is {@code int}.
   * Default value is {@code 7}.
   * </li>
   * <li>
   * Property {@code ignoreOverriddenMethods} - Ignore number of parameters for
   * methods with {@code @Override} annotation.
   * Type is {@code boolean}.
   * Default value is {@code false}.
   * </li>
   * <li>
   * Property {@code tokens} - tokens to check
   * Type is {@code java.lang.String[]}.
   * Validation type is {@code tokenSet}.
   * Default value is:
   * <a href="https://checkstyle.org/apidocs/com/puppycrawl/tools/checkstyle/api/TokenTypes.html#METHOD_DEF">
   * METHOD_DEF</a>,
   * <a href="https://checkstyle.org/apidocs/com/puppycrawl/tools/checkstyle/api/TokenTypes.html#CTOR_DEF">
   * CTOR_DEF</a>.
   * </li>
   * </ul>
   * <p>
   * To configure the check:
   * </p>
   * <pre>
   * &lt;module name="ParameterNumber"/&gt;
   * </pre>
   * <p>
   * To configure the check to allow 10 parameters for a method:
   * </p>
   * <pre>
   * &lt;module name="ParameterNumber"&gt;
   *   &lt;property name="max" value="10"/&gt;
   *   &lt;property name="tokens" value="METHOD_DEF"/&gt;
   * &lt;/module&gt;
   * </pre>
   * <p>
   * To configure the check to ignore number of parameters for methods with
   * {@code @Override} or {@code @java.lang.Override annotation}.
   * </p>
   * <p>
   * Rationale: developer may need to override method with many parameters from
   * 3-rd party library. In this case developer has no control over number of parameters.
   * </p>
   * <pre>
   * &lt;module name="ParameterNumber"&gt;
   *   &lt;property name="ignoreOverriddenMethods" value="true"/&gt;
   * &lt;/module&gt;
   * </pre>
   * <p>
   * Java code example:
   * </p>
   * <pre>
   * &#064;Override
   * public void needsLotsOfParameters(int a,
   *     int b, int c, int d, int e, int f, int g, int h) {
   *     ...
   * }
   * </pre>
   * <p>
   * Parent is {@code com.puppycrawl.tools.checkstyle.TreeWalker}
   * </p>
   * <p>
   * Violation Message Keys:
   * </p>
   * <ul>
   * <li>
   * {@code maxParam}
   * </li>
   * </ul>
   *
   * @since 3.0
   */
  @StatelessCheck
  public class ParameterNumberCheck
      extends AbstractCheck {
  
      /**
       * A key is pointing to the warning message text in "messages.properties"
       * file.
       */
      public static final String MSG_KEY = "maxParam";
  
      /** Default maximum number of allowed parameters. */
      private static final int DEFAULT_MAX_PARAMETERS = 7;
  
      /** Specify the maximum number of parameters allowed. */
      private int max = DEFAULT_MAX_PARAMETERS;
  
      /** Ignore number of parameters for methods with {@code @Override} annotation. */
      private boolean ignoreOverriddenMethods;
  
      /**
       * Setter to specify the maximum number of parameters allowed.
       *
       * @param max the max allowed parameters
       */
      public void setMax(int max) {
          this.max = max;
      }
  
      /**
       * Setter to ignore number of parameters for methods with {@code @Override} annotation.
       *
       * @param ignoreOverriddenMethods set ignore overridden methods
       */
      public void setIgnoreOverriddenMethods(boolean ignoreOverriddenMethods) {
          this.ignoreOverriddenMethods = ignoreOverriddenMethods;
      }
  
      @Override
      public int[] getDefaultTokens() {
          return getAcceptableTokens();
      }
  
      @Override
      public int[] getAcceptableTokens() {
          return new int[] {TokenTypes.METHOD_DEF, TokenTypes.CTOR_DEF};
      }
  
      @Override
      public int[] getRequiredTokens() {
          return CommonUtil.EMPTY_INT_ARRAY;
      }
  
      @Override
      public void visitToken(DetailAST ast) {
          final DetailAST params = ast.findFirstToken(TokenTypes.PARAMETERS);
          final int count = params.getChildCount(TokenTypes.PARAMETER_DEF);
          if (count > max && !shouldIgnoreNumberOfParameters(ast)) {
              final DetailAST name = ast.findFirstToken(TokenTypes.IDENT);
              log(name, MSG_KEY, max, count);
          }
      }
  
      /**
       * Determine whether to ignore number of parameters for the method.
       *
       * @param ast the token to process
       * @return true if this is overridden method and number of parameters should be ignored
       *         false otherwise
       */
      private boolean shouldIgnoreNumberOfParameters(DetailAST ast) {
          // if you override a method, you have no power over the number of parameters
          return ignoreOverriddenMethods
                  && AnnotationUtil.hasOverrideAnnotation(ast);
      }
  
  }
  