/*
    * Licensed to the Apache Software Foundation (ASF) under one or more
    * contributor license agreements. See the NOTICE file distributed with
    * this work for additional information regarding copyright ownership.
    * The ASF licenses this file to You under the Apache license, Version 2.0
    * (the "License"); you may not use this file except in compliance with
    * the License. You may obtain a copy of the License at
    *
    *      http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the license for the specific language governing permissions and
   * limitations under the license.
   */
  package org.apache.logging.log4j.core.pattern;
  
  import org.apache.logging.log4j.core.LogEvent;
  import org.apache.logging.log4j.core.config.plugins.Plugin;
  import org.apache.logging.log4j.util.ProcessIdUtil;
  
  @Plugin(name = "ProcessIdPatternConverter", category = "Converter")
  @ConverterKeys({ "pid", "processId" })
  public final class ProcessIdPatternConverter extends LogEventPatternConverter {
      private static final String DEFAULT_DEFAULT_VALUE = "???";
      private final String pid;
  
      /**
       * Private constructor.
       */
      private ProcessIdPatternConverter(final String... options) {
          super("Process ID", "pid");
          final String defaultValue = options.length > 0 ? options[0] : DEFAULT_DEFAULT_VALUE;
          final String discoveredPid = ProcessIdUtil.getProcessId();
          pid = discoveredPid.equals(ProcessIdUtil.DEFAULT_PROCESSID) ? defaultValue : discoveredPid;
      }
  
      /**
       * Returns the process ID.
       * @return the process ID
       */
      public String getProcessId() {
          return pid;
      }
  
      public static void main(final String[] args) {
          System.out.println(new ProcessIdPatternConverter().pid);
      }
  
      /**
       * Obtains an instance of ProcessIdPatternConverter.
       *
       * @param options options, currently ignored, may be null.
       * @return instance of ProcessIdPatternConverter.
       */
      public static ProcessIdPatternConverter newInstance(final String[] options) {
          return new ProcessIdPatternConverter(options);
      }
  
      /**
       * {@inheritDoc}
       */
      @Override
      public void format(final LogEvent event, final StringBuilder toAppendTo) {
          toAppendTo.append(pid);
      }
  }