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;
  
  import java.util.Locale;
  
  import com.puppycrawl.tools.checkstyle.api.AuditEvent;
  import com.puppycrawl.tools.checkstyle.api.SeverityLevel;
  
  /**
   * Represents the default formatter for log message.
   * Default log message format is:
   * [SEVERITY LEVEL] filePath:lineNo:columnNo: message. [CheckName]
   * When the module id of the message has been set, the format is:
   * [SEVERITY LEVEL] filePath:lineNo:columnNo: message. [ModuleId]
   */
  public class AuditEventDefaultFormatter implements AuditEventFormatter {
  
      /** Length of all separators. */
      private static final int LENGTH_OF_ALL_SEPARATORS = 10;
  
      /** Suffix of module names like XXXXCheck. */
      private static final String SUFFIX = "Check";
  
      @Override
      public String format(AuditEvent event) {
          final String fileName = event.getFileName();
          final String message = event.getMessage();
  
          final SeverityLevel severityLevel = event.getSeverityLevel();
          final String severityLevelName;
          if (severityLevel == SeverityLevel.WARNING) {
              // We change the name of severity level intentionally
              // to shorten the length of the log message.
              severityLevelName = "WARN";
          }
          else {
              severityLevelName = severityLevel.getName().toUpperCase(Locale.US);
          }
  
          // Avoid StringBuffer.expandCapacity
          final int bufLen = calculateBufferLength(event, severityLevelName.length());
          final StringBuilder sb = new StringBuilder(bufLen);
  
          sb.append('[').append(severityLevelName).append("] ")
              .append(fileName).append(':').append(event.getLine());
          if (event.getColumn() > 0) {
              sb.append(':').append(event.getColumn());
          }
          sb.append(": ").append(message).append(" [");
          if (event.getModuleId() == null) {
              final String checkShortName = getCheckShortName(event);
              sb.append(checkShortName);
          }
          else {
              sb.append(event.getModuleId());
          }
          sb.append(']');
  
          return sb.toString();
      }
  
      /**
       * Returns the length of the buffer for StringBuilder.
       * bufferLength = fileNameLength + messageLength + lengthOfAllSeparators +
       * + severityNameLength + checkNameLength.
       *
       * @param event audit event.
       * @param severityLevelNameLength length of severity level name.
       * @return the length of the buffer for StringBuilder.
       */
      private static int calculateBufferLength(AuditEvent event, int severityLevelNameLength) {
          return LENGTH_OF_ALL_SEPARATORS + event.getFileName().length()
              + event.getMessage().length() + severityLevelNameLength
              + getCheckShortName(event).length();
      }
  
      /**
       * Returns check name without 'Check' suffix.
       *
       * @param event audit event.
       * @return check name without 'Check' suffix.
       */
      private static String getCheckShortName(AuditEvent event) {
          final String checkFullName = event.getSourceName();
          String checkShortName = checkFullName.substring(checkFullName.lastIndexOf('.') + 1);
          if (checkShortName.endsWith(SUFFIX)) {
              final int endIndex = checkShortName.length() - SUFFIX.length();
              checkShortName = checkShortName.substring(0, endIndex);
          }
          return checkShortName;
      }
  
  }
  