/**
    * Logback: the reliable, generic, fast and flexible logging framework.
    * Copyright (C) 1999-2021, QOS.ch. All rights reserved.
    *
    * This program and the accompanying materials are dual-licensed under
    * either the terms of the Eclipse Public License v1.0 as published by
    * the Eclipse Foundation
    *
    *   or (per the licensee's choosing)
   *
   * under the terms of the GNU Lesser General Public License version 2.1
   * as published by the Free Software Foundation.
   */
  package ch.qos.logback.classic.pattern;
  
  import ch.qos.logback.classic.PatternLayout;
  import ch.qos.logback.classic.spi.ILoggingEvent;
  import ch.qos.logback.core.pattern.CompositeConverter;
  import ch.qos.logback.core.pattern.Converter;
  
  public class PrefixCompositeConverter extends CompositeConverter<ILoggingEvent> {
  
      public String convert(ILoggingEvent event) {
          StringBuilder buf = new StringBuilder();
          Converter<ILoggingEvent> childConverter = this.getChildConverter();
  
          for (Converter<ILoggingEvent> c = childConverter; c != null; c = c.getNext()) {
              if (c instanceof MDCConverter) {
                  MDCConverter mdcConverter = (MDCConverter) c;
  
                  String key = mdcConverter.getKey();
                  if (key != null) {
                      buf.append(key).append("=");
                  }
              } else if (c instanceof PropertyConverter) {
                  PropertyConverter pc = (PropertyConverter) c;
                  String key = pc.getKey();
                  if (key != null) {
                      buf.append(key).append("=");
                  }
              } else {
                  String classOfConverter = c.getClass().getName();
  
                  String key = PatternLayout.CONVERTER_CLASS_TO_KEY_MAP.get(classOfConverter);
                  if (key != null)
                      buf.append(key).append("=");
              }
              buf.append(c.convert(event));
          }
          return buf.toString();
      }
  
      protected String transform(ILoggingEvent event, String in) {
          throw new UnsupportedOperationException();
      }
  }