1 /* 2 * Licensed to the Apache Software Foundation (ASF) under one or more 3 * contributor license agreements. See the NOTICE file distributed with 4 * this work for additional information regarding copyright ownership. 5 * The ASF licenses this file to You under the Apache license, Version 2.0 6 * (the "License"); you may not use this file except in compliance with 7 * the License. You may obtain a copy of the License at 8 * 9 * http://www.apache.org/licenses/LICENSE-2.0 10 * 11 * Unless required by applicable law or agreed to in writing, software 12 * distributed under the License is distributed on an "AS IS" BASIS, 13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 14 * See the license for the specific language governing permissions and 15 * limitations under the license. 16 */ 17 package org.apache.logging.log4j.core.pattern; 18 19 import org.apache.logging.log4j.Logger; 20 import org.apache.logging.log4j.core.LogEvent; 21 import org.apache.logging.log4j.status.StatusLogger; 22 23 /** 24 * LoggingEventPatternConverter is a base class for pattern converters 25 * that can format information from instances of LoggingEvent. 26 */ 27 public abstract class LogEventPatternConverter extends AbstractPatternConverter { 28 29 /** 30 * Allow subclasses access to the status logger without creating another instance. 31 */ 32 protected static final Logger LOGGER = StatusLogger.getLogger(); 33 34 /** 35 * Constructs an instance of LoggingEventPatternConverter. 36 * 37 * @param name name of converter. 38 * @param style CSS style for output. 39 */ 40 protected LogEventPatternConverter(final String name, final String style) { 41 super(name, style); 42 } 43 44 /** 45 * Formats an event into a string buffer. 46 * 47 * @param event event to format, may not be null. 48 * @param toAppendTo string buffer to which the formatted event will be appended. May not be null. 49 */ 50 public abstract void format(final LogEvent event, final StringBuilder toAppendTo); 51 52 /** 53 * {@inheritDoc} 54 */ 55 public void format(final Object obj, final StringBuilder output) { 56 if (obj instanceof LogEvent) { 57 format((LogEvent) obj, output); 58 } 59 } 60 61 /** 62 * Normally pattern converters are not meant to handle Exceptions although 63 * few pattern converters might. 64 * <p/> 65 * By examining the return values for this method, the containing layout will 66 * determine whether it handles throwables or not. 67 * 68 * @return true if this PatternConverter handles throwables 69 */ 70 public boolean handlesThrowable() { 71 return false; 72 } 73 }