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 */ 017package org.apache.logging.log4j.core.pattern; 018 019import java.util.concurrent.atomic.AtomicLong; 020 021import org.apache.logging.log4j.core.LogEvent; 022import org.apache.logging.log4j.core.config.plugins.Plugin; 023import org.apache.logging.log4j.util.PerformanceSensitive; 024 025/** 026 * Formats the event sequence number. 027 */ 028@Plugin(name = "SequenceNumberPatternConverter", category = "Converter") 029@ConverterKeys({ "sn", "sequenceNumber" }) 030@PerformanceSensitive("allocation") 031public final class SequenceNumberPatternConverter extends LogEventPatternConverter { 032 033 private static final AtomicLong SEQUENCE = new AtomicLong(); 034 035 /** 036 * Singleton. 037 */ 038 private static final SequenceNumberPatternConverter INSTANCE = 039 new SequenceNumberPatternConverter(); 040 041 /** 042 * Private constructor. 043 */ 044 private SequenceNumberPatternConverter() { 045 super("Sequence Number", "sn"); 046 } 047 048 /** 049 * Obtains an instance of SequencePatternConverter. 050 * 051 * @param options options, currently ignored, may be null. 052 * @return instance of SequencePatternConverter. 053 */ 054 public static SequenceNumberPatternConverter newInstance(final String[] options) { 055 return INSTANCE; 056 } 057 058 /** 059 * {@inheritDoc} 060 */ 061 @Override 062 public void format(final LogEvent event, final StringBuilder toAppendTo) { 063 toAppendTo.append(SEQUENCE.incrementAndGet()); 064 } 065}