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.core.LogEvent; 020 import org.apache.logging.log4j.core.config.plugins.Plugin; 021 import org.apache.logging.log4j.core.helpers.Constants; 022 import org.apache.logging.log4j.core.impl.ThrowableFormatOptions; 023 024 import java.io.PrintWriter; 025 import java.io.StringWriter; 026 027 028 /** 029 * Outputs the Throwable portion of the LoggingEvent as a full stacktrace 030 * unless this converter's option is 'short', where it just outputs the first line of the trace, or if 031 * the number of lines to print is explicitly specified. 032 */ 033 @Plugin(name = "ThrowablePatternConverter", type = "Converter") 034 @ConverterKeys({"ex", "throwable", "exception" }) 035 public class ThrowablePatternConverter extends LogEventPatternConverter { 036 037 /** 038 * The number of lines to write. 039 */ 040 protected final ThrowableFormatOptions options; 041 042 /** 043 * Constructor. 044 * @param name Name of converter. 045 * @param style CSS style for output. 046 * @param options options, may be null. 047 */ 048 protected ThrowablePatternConverter(final String name, final String style, final String[] options) { 049 super(name, style); 050 this.options = ThrowableFormatOptions.newInstance(options); 051 } 052 053 /** 054 * Gets an instance of the class. 055 * 056 * @param options pattern options, may be null. If first element is "short", 057 * only the first line of the throwable will be formatted. 058 * @return instance of class. 059 */ 060 public static ThrowablePatternConverter newInstance(final String[] options) { 061 return new ThrowablePatternConverter("Throwable", "throwable", options); 062 } 063 064 /** 065 * {@inheritDoc} 066 */ 067 @Override 068 public void format(final LogEvent event, final StringBuilder toAppendTo) { 069 final Throwable t = event.getThrown(); 070 071 if (t != null && options.anyLines()) { 072 final StringWriter w = new StringWriter(); 073 t.printStackTrace(new PrintWriter(w)); 074 final int len = toAppendTo.length(); 075 if (len > 0 && !Character.isWhitespace(toAppendTo.charAt(len - 1))) { 076 toAppendTo.append(" "); 077 } 078 if (!options.allLines() || !Constants.LINE_SEP.equals(options.getSeparator())) { 079 final StringBuilder sb = new StringBuilder(); 080 final String[] array = w.toString().split(Constants.LINE_SEP); 081 final int limit = options.minLines(array.length) - 1; 082 for (int i = 0; i <= limit; ++i) { 083 sb.append(array[i]); 084 if (i < limit) { 085 sb.append(options.getSeparator()); 086 } 087 } 088 toAppendTo.append(sb.toString()); 089 090 } else { 091 toAppendTo.append(w.toString()); 092 } 093 } 094 } 095 096 /** 097 * This converter obviously handles throwables. 098 * 099 * @return true. 100 */ 101 @Override 102 public boolean handlesThrowable() { 103 return true; 104 } 105 }