/**
    * Logback: the reliable, generic, fast and flexible logging framework.
    * Copyright (C) 1999-2015, 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.access.common.pattern;
  
  import ch.qos.logback.access.common.spi.IAccessEvent;
  import ch.qos.logback.core.util.OptionHelper;
  
  public class RequestHeaderConverter extends AccessConverter {
  
      String key;
  
      @Override
      public void start() {
          key = getFirstOption();
          if (OptionHelper.isNullOrEmpty(key)) {
              addWarn("Missing key for the requested header. Defaulting to all keys.");
              key = null;
          }
          super.start();
      }
  
      @Override
      public String convert(IAccessEvent accessEvent) {
          if (!isStarted()) {
              return "INACTIVE_HEADER_CONV";
          }
  
          if (key != null) {
              return accessEvent.getRequestHeader(key);
          } else {
              return accessEvent.getRequestHeaderMap().toString();
          }
      }
  
  }