/**
    * Logback: the reliable, generic, fast and flexible logging framework.
    * Copyright (C) 1999-2011, 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 java.util.Map;
  
  import ch.qos.logback.classic.spi.ILoggingEvent;
  import ch.qos.logback.classic.spi.LoggerContextVO;
  
  public final class PropertyConverter extends ClassicConverter {
  
    String key;
  
    public void start() {
      String optStr = getFirstOption();
      if (optStr != null) {
        key = optStr;
        super.start();
      }
    }
  
    public String convert(ILoggingEvent event) {
      if (key == null) {
        return "Property_HAS_NO_KEY";
      } else {
        LoggerContextVO lcvo = event.getLoggerContextVO();
        Map<String, String> map = lcvo.getPropertyMap();
        String val = map.get(key);
        if (val != null) {
          return val;
        } else {
          return System.getProperty(key);
        }
      }
    }
  }