001/*
002 * Licensed to the Apache Software Foundation (ASF) under one or more
003 * contributor license agreements.  See the NOTICE file distributed with
004 * this work for additional information regarding copyright ownership.
005 * The ASF licenses this file to You under the Apache License, Version 2.0
006 * (the "License"); you may not use this file except in compliance with
007 * the License.  You may obtain a copy of the License at
008 *
009 *      http://www.apache.org/licenses/LICENSE-2.0
010 *
011 * Unless required by applicable law or agreed to in writing, software
012 * distributed under the License is distributed on an "AS IS" BASIS,
013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014 * See the License for the specific language governing permissions and
015 * limitations under the License.
016 */
017
018package org.apache.log4j.pattern;
019
020import org.apache.log4j.spi.LoggingEvent;
021
022
023/**
024 * Formats the event sequence number.
025 *
026 * @author Ceki Gülcü
027 */
028public class SequenceNumberPatternConverter
029  extends LoggingEventPatternConverter {
030  /**
031   * Singleton.
032   */
033  private static final SequenceNumberPatternConverter INSTANCE =
034    new SequenceNumberPatternConverter();
035
036  /**
037   * Private constructor.
038   */
039  private SequenceNumberPatternConverter() {
040    super("Sequence Number", "sn");
041  }
042
043  /**
044   * Obtains an instance of SequencePatternConverter.
045   * @param options options, currently ignored, may be null.
046   * @return instance of SequencePatternConverter.
047   */
048  public static SequenceNumberPatternConverter newInstance(
049    final String[] options) {
050    return INSTANCE;
051  }
052
053  /**
054   * {@inheritDoc}
055   */
056  public void format(final LoggingEvent event, final StringBuffer toAppendTo) {
057    toAppendTo.append("0");
058  }
059}