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.whitespace;
  
  import java.util.Arrays;
  import java.util.Locale;
  
  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.CodePointUtil;
  import com.puppycrawl.tools.checkstyle.utils.CommonUtil;
  
  /**
   * <p>
   * Checks line wrapping with separators.
   * </p>
   * <ul>
   * <li>
   * Property {@code option} - Specify policy on how to wrap lines.
   * Type is {@code com.puppycrawl.tools.checkstyle.checks.whitespace.WrapOption}.
   * Default value is {@code eol}.
   * </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#DOT">
   * DOT</a>,
   * <a href="https://checkstyle.org/apidocs/com/puppycrawl/tools/checkstyle/api/TokenTypes.html#COMMA">
   * COMMA</a>.
   * </li>
   * </ul>
   *  <p>
   * To configure the check:
   * </p>
   * <pre>
   * &lt;module name=&quot;SeparatorWrap&quot;/&gt;
   * </pre>
   * <p>
   * Example:
   * </p>
   * <pre>
   * import java.io.
   *          IOException; // OK
   *
   * class Test {
   *
   *   String s;
   *
   *   public void foo(int a,
   *                     int b) { // OK
   *   }
   *
   *   public void bar(int p
   *                     , int q) { // violation, separator comma on new line
   *     if (s
   *           .isEmpty()) { // violation, separator dot on new line
   *     }
   *   }
   *
   * }
   * </pre>
   * <p>
   * To configure the check for
   * <a href="https://checkstyle.org/apidocs/com/puppycrawl/tools/checkstyle/api/TokenTypes.html#METHOD_REF">
   * METHOD_REF</a> at new line:
   * </p>
   * <pre>
   * &lt;module name=&quot;SeparatorWrap&quot;&gt;
   *   &lt;property name=&quot;tokens&quot; value=&quot;METHOD_REF&quot;/&gt;
   *   &lt;property name=&quot;option&quot; value=&quot;nl&quot;/&gt;
   * &lt;/module&gt;
   * </pre>
   * <p>
   * Example:
   * </p>
   * <pre>
   * import java.util.Arrays;
   *
   * class Test2 {
   *
   *   String[] stringArray = {&quot;foo&quot;, &quot;bar&quot;};
   *
   *   void fun() {
   *     Arrays.sort(stringArray, String::
   *       compareToIgnoreCase);  // violation, separator method reference on same line
   *     Arrays.sort(stringArray, String
   *       ::compareTo);  // OK
   *   }
   *
   * }
   * </pre>
   * <p>
   * To configure the check for comma at the new line:
   * </p>
   * <pre>
   * &lt;module name=&quot;SeparatorWrap&quot;&gt;
   *   &lt;property name=&quot;tokens&quot; value=&quot;COMMA&quot;/&gt;
   *   &lt;property name=&quot;option&quot; value=&quot;nl&quot;/&gt;
   * &lt;/module&gt;
   * </pre>
   * <p>
   * Example:
   * </p>
   * <pre>
   * class Test3 {
   *
   *   String s;
   *
   *   int a,
   *     b;  // violation, separator comma on same line
   *
   *   public void foo(int a,
   *                      int b) {  // violation, separator comma on the same line
   *     int r
   *       , t; // OK
   *   }
   *
   *   public void bar(int p
   *                     , int q) {  // OK
   *   }
   *
   * }
   * </pre>
   * <p>
   * Parent is {@code com.puppycrawl.tools.checkstyle.TreeWalker}
   * </p>
   * <p>
   * Violation Message Keys:
   * </p>
   * <ul>
   * <li>
   * {@code line.new}
   * </li>
   * <li>
   * {@code line.previous}
   * </li>
   * </ul>
   *
   * @since 5.8
   */
  @StatelessCheck
  public class SeparatorWrapCheck
      extends AbstractCheck {
  
      /**
       * A key is pointing to the warning message text in "messages.properties"
       * file.
       */
      public static final String MSG_LINE_PREVIOUS = "line.previous";
  
      /**
       * A key is pointing to the warning message text in "messages.properties"
       * file.
       */
      public static final String MSG_LINE_NEW = "line.new";
  
      /** Specify policy on how to wrap lines. */
      private WrapOption option = WrapOption.EOL;
  
      /**
       * Setter to specify policy on how to wrap lines.
       *
       * @param optionStr string to decode option from
       * @throws IllegalArgumentException if unable to decode
       */
      public void setOption(String optionStr) {
          option = WrapOption.valueOf(optionStr.trim().toUpperCase(Locale.ENGLISH));
      }
  
      @Override
      public int[] getDefaultTokens() {
          return new int[] {
              TokenTypes.DOT,
              TokenTypes.COMMA,
          };
      }
  
      @Override
      public int[] getAcceptableTokens() {
          return new int[] {
              TokenTypes.DOT,
              TokenTypes.COMMA,
              TokenTypes.SEMI,
              TokenTypes.ELLIPSIS,
              TokenTypes.AT,
              TokenTypes.LPAREN,
              TokenTypes.RPAREN,
              TokenTypes.ARRAY_DECLARATOR,
              TokenTypes.RBRACK,
              TokenTypes.METHOD_REF,
          };
      }
  
      @Override
      public int[] getRequiredTokens() {
          return CommonUtil.EMPTY_INT_ARRAY;
      }
  
      @Override
      public void visitToken(DetailAST ast) {
          final String text = ast.getText();
          final int colNo = ast.getColumnNo();
          final int lineNo = ast.getLineNo();
          final int[] currentLine = getLineCodePoints(lineNo - 1);
          final int[] substringAfterToken = CodePointUtil.trim(
                  Arrays.copyOfRange(currentLine, colNo + text.length(), currentLine.length)
          );
          final int[] substringBeforeToken = CodePointUtil.trim(
                  Arrays.copyOfRange(currentLine, 0, colNo)
          );
  
          if (option == WrapOption.EOL
                  && substringBeforeToken.length == 0) {
              log(ast, MSG_LINE_PREVIOUS, text);
          }
          else if (option == WrapOption.NL
                   && substringAfterToken.length == 0) {
              log(ast, MSG_LINE_NEW, text);
          }
      }
  
  }
  