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 java.io.PrintWriter;
020 import java.io.StringWriter;
021
022 import org.apache.logging.log4j.core.LogEvent;
023 import org.apache.logging.log4j.core.config.plugins.Plugin;
024 import org.apache.logging.log4j.core.impl.ThrowableFormatOptions;
025 import org.apache.logging.log4j.core.util.Constants;
026 import org.apache.logging.log4j.util.Strings;
027
028
029 /**
030 * Outputs the Throwable portion of the LoggingEvent as a full stacktrace
031 * unless this converter's option is 'short', where it just outputs the first line of the trace, or if
032 * the number of lines to print is explicitly specified.
033 */
034 @Plugin(name = "ThrowablePatternConverter", category = PatternConverter.CATEGORY)
035 @ConverterKeys({ "ex", "throwable", "exception" })
036 public class ThrowablePatternConverter extends LogEventPatternConverter {
037
038 private String rawOption;
039
040 /**
041 * The number of lines to write.
042 */
043 protected final ThrowableFormatOptions options;
044
045 /**
046 * Constructor.
047 * @param name Name of converter.
048 * @param style CSS style for output.
049 * @param options options, may be null.
050 */
051 protected ThrowablePatternConverter(final String name, final String style, final String[] options) {
052 super(name, style);
053 this.options = ThrowableFormatOptions.newInstance(options);
054 if (options != null && options.length > 0) {
055 rawOption = options[0];
056 }
057 }
058
059 /**
060 * Gets an instance of the class.
061 *
062 * @param options pattern options, may be null. If first element is "short",
063 * only the first line of the throwable will be formatted.
064 * @return instance of class.
065 */
066 public static ThrowablePatternConverter newInstance(final String[] options) {
067 return new ThrowablePatternConverter("Throwable", "throwable", options);
068 }
069
070 /**
071 * {@inheritDoc}
072 */
073 @Override
074 public void format(final LogEvent event, final StringBuilder buffer) {
075 final Throwable t = event.getThrown();
076
077 if (isSubShortOption()) {
078 formatSubShortOption(t, buffer);
079 }
080 else if (t != null && options.anyLines()) {
081 formatOption(t, buffer);
082 }
083 }
084
085 private boolean isSubShortOption() {
086 return ThrowableFormatOptions.MESSAGE.equalsIgnoreCase(rawOption) ||
087 ThrowableFormatOptions.LOCALIZED_MESSAGE.equalsIgnoreCase(rawOption) ||
088 ThrowableFormatOptions.FILE_NAME.equalsIgnoreCase(rawOption) ||
089 ThrowableFormatOptions.LINE_NUMBER.equalsIgnoreCase(rawOption) ||
090 ThrowableFormatOptions.METHOD_NAME.equalsIgnoreCase(rawOption) ||
091 ThrowableFormatOptions.CLASS_NAME.equalsIgnoreCase(rawOption);
092 }
093
094 private void formatSubShortOption(final Throwable t, final StringBuilder buffer) {
095 StackTraceElement[] trace;
096 StackTraceElement throwingMethod = null;
097 int len;
098
099 if (t != null) {
100 trace = t.getStackTrace();
101 if (trace !=null && trace.length > 0) {
102 throwingMethod = trace[0];
103 }
104 }
105
106 if (t != null && throwingMethod != null) {
107 String toAppend = Strings.EMPTY;
108
109 if (ThrowableFormatOptions.CLASS_NAME.equalsIgnoreCase(rawOption)) {
110 toAppend = throwingMethod.getClassName();
111 }
112 else if (ThrowableFormatOptions.METHOD_NAME.equalsIgnoreCase(rawOption)) {
113 toAppend = throwingMethod.getMethodName();
114 }
115 else if (ThrowableFormatOptions.LINE_NUMBER.equalsIgnoreCase(rawOption)) {
116 toAppend = String.valueOf(throwingMethod.getLineNumber());
117 }
118 else if (ThrowableFormatOptions.MESSAGE.equalsIgnoreCase(rawOption)) {
119 toAppend = t.getMessage();
120 }
121 else if (ThrowableFormatOptions.LOCALIZED_MESSAGE.equalsIgnoreCase(rawOption)) {
122 toAppend = t.getLocalizedMessage();
123 }
124 else if (ThrowableFormatOptions.FILE_NAME.equalsIgnoreCase(rawOption)) {
125 toAppend = throwingMethod.getFileName();
126 }
127
128 len = buffer.length();
129 if (len > 0 && !Character.isWhitespace(buffer.charAt(len - 1))) {
130 buffer.append(' ');
131 }
132 buffer.append(toAppend);
133 }
134 }
135
136 private void formatOption(final Throwable throwable, final StringBuilder buffer) {
137 final StringWriter w = new StringWriter();
138
139 throwable.printStackTrace(new PrintWriter(w));
140 final int len = buffer.length();
141 if (len > 0 && !Character.isWhitespace(buffer.charAt(len - 1))) {
142 buffer.append(' ');
143 }
144 if (!options.allLines() || !Constants.LINE_SEPARATOR.equals(options.getSeparator())) {
145 final StringBuilder sb = new StringBuilder();
146 final String[] array = w.toString().split(Constants.LINE_SEPARATOR);
147 final int limit = options.minLines(array.length) - 1;
148 for (int i = 0; i <= limit; ++i) {
149 sb.append(array[i]);
150 if (i < limit) {
151 sb.append(options.getSeparator());
152 }
153 }
154 buffer.append(sb.toString());
155
156 } else {
157 buffer.append(w.toString());
158 }
159 }
160
161 /**
162 * This converter obviously handles throwables.
163 *
164 * @return true.
165 */
166 @Override
167 public boolean handlesThrowable() {
168 return true;
169 }
170 }