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 package org.apache.logging.log4j.core.pattern; 018 019 import org.apache.logging.log4j.Logger; 020 import org.apache.logging.log4j.core.LogEvent; 021 import org.apache.logging.log4j.status.StatusLogger; 022 023 /** 024 * LoggingEventPatternConverter is a base class for pattern converters 025 * that can format information from instances of LoggingEvent. 026 */ 027 public abstract class LogEventPatternConverter extends AbstractPatternConverter { 028 029 /** 030 * Allow subclasses access to the status logger without creating another instance. 031 */ 032 protected static final Logger LOGGER = StatusLogger.getLogger(); 033 034 /** 035 * Constructs an instance of LoggingEventPatternConverter. 036 * 037 * @param name name of converter. 038 * @param style CSS style for output. 039 */ 040 protected LogEventPatternConverter(final String name, final String style) { 041 super(name, style); 042 } 043 044 /** 045 * Formats an event into a string buffer. 046 * 047 * @param event event to format, may not be null. 048 * @param toAppendTo string buffer to which the formatted event will be appended. May not be null. 049 */ 050 public abstract void format(final LogEvent event, final StringBuilder toAppendTo); 051 052 /** 053 * {@inheritDoc} 054 */ 055 @Override 056 public void format(final Object obj, final StringBuilder output) { 057 if (obj instanceof LogEvent) { 058 format((LogEvent) obj, output); 059 } 060 } 061 062 /** 063 * Normally pattern converters are not meant to handle Exceptions although 064 * few pattern converters might. 065 * <p/> 066 * By examining the return values for this method, the containing layout will 067 * determine whether it handles throwables or not. 068 * 069 * @return true if this PatternConverter handles throwables 070 */ 071 public boolean handlesThrowable() { 072 return false; 073 } 074 }