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.layout;
018
019 import java.nio.charset.Charset;
020 import java.util.HashMap;
021 import java.util.List;
022 import java.util.Map;
023
024 import org.apache.logging.log4j.core.LogEvent;
025 import org.apache.logging.log4j.core.config.Configuration;
026 import org.apache.logging.log4j.core.config.plugins.Plugin;
027 import org.apache.logging.log4j.core.config.plugins.PluginAttribute;
028 import org.apache.logging.log4j.core.config.plugins.PluginConfiguration;
029 import org.apache.logging.log4j.core.config.plugins.PluginElement;
030 import org.apache.logging.log4j.core.config.plugins.PluginFactory;
031 import org.apache.logging.log4j.core.helpers.Booleans;
032 import org.apache.logging.log4j.core.helpers.Charsets;
033 import org.apache.logging.log4j.core.helpers.OptionConverter;
034 import org.apache.logging.log4j.core.pattern.LogEventPatternConverter;
035 import org.apache.logging.log4j.core.pattern.PatternFormatter;
036 import org.apache.logging.log4j.core.pattern.PatternParser;
037 import org.apache.logging.log4j.core.pattern.RegexReplacement;
038
039 /**
040 * <p>A flexible layout configurable with pattern string. The goal of this class
041 * is to {@link org.apache.logging.log4j.core.Layout#toByteArray format} a {@link LogEvent} and return the results.
042 * The format of the result depends on the <em>conversion pattern</em>.
043 * <p>
044 * <p/>
045 * <p>The conversion pattern is closely related to the conversion
046 * pattern of the printf function in C. A conversion pattern is
047 * composed of literal text and format control expressions called
048 * <em>conversion specifiers</em>.
049 *
050 * See the Log4j Manual for details on the supported pattern converters.
051 */
052 @Plugin(name = "PatternLayout", category = "Core", elementType = "layout", printObject = true)
053 public final class PatternLayout extends AbstractStringLayout {
054 /**
055 * Default pattern string for log output. Currently set to the
056 * string <b>"%m%n"</b> which just prints the application supplied
057 * message.
058 */
059 public static final String DEFAULT_CONVERSION_PATTERN = "%m%n";
060
061 /**
062 * A conversion pattern equivalent to the TTCCCLayout.
063 * Current value is <b>%r [%t] %p %c %x - %m%n</b>.
064 */
065 public static final String TTCC_CONVERSION_PATTERN =
066 "%r [%t] %p %c %x - %m%n";
067
068 /**
069 * A simple pattern.
070 * Current value is <b>%d [%t] %p %c - %m%n</b>.
071 */
072 public static final String SIMPLE_CONVERSION_PATTERN =
073 "%d [%t] %p %c - %m%n";
074
075 /** Key to identify pattern converters. */
076 public static final String KEY = "Converter";
077
078 /**
079 * Initial converter for pattern.
080 */
081 private List<PatternFormatter> formatters;
082
083 /**
084 * Conversion pattern.
085 */
086 private final String conversionPattern;
087
088
089 /**
090 * The current Configuration.
091 */
092 private final Configuration config;
093
094 private final RegexReplacement replace;
095
096 private final boolean alwaysWriteExceptions;
097
098 /**
099 * Constructs a EnhancedPatternLayout using the supplied conversion pattern.
100 *
101 * @param config The Configuration.
102 * @param replace The regular expression to match.
103 * @param pattern conversion pattern.
104 * @param charset The character set.
105 * @param alwaysWriteExceptions Whether or not exceptions should always be handled in this pattern (if {@code true},
106 * exceptions will be written even if the pattern does not specify so).
107 */
108 private PatternLayout(final Configuration config, final RegexReplacement replace, final String pattern,
109 final Charset charset, final boolean alwaysWriteExceptions) {
110 super(charset);
111 this.replace = replace;
112 this.conversionPattern = pattern;
113 this.config = config;
114 this.alwaysWriteExceptions = alwaysWriteExceptions;
115 final PatternParser parser = createPatternParser(config);
116 formatters = parser.parse(pattern == null ? DEFAULT_CONVERSION_PATTERN : pattern, this.alwaysWriteExceptions);
117 }
118
119 /**
120 * Set the <b>ConversionPattern</b> option. This is the string which
121 * controls formatting and consists of a mix of literal content and
122 * conversion specifiers.
123 *
124 * @param conversionPattern conversion pattern.
125 */
126 public void setConversionPattern(final String conversionPattern) {
127 final String pattern = OptionConverter.convertSpecialChars(conversionPattern);
128 if (pattern == null) {
129 return;
130 }
131 final PatternParser parser = createPatternParser(this.config);
132 formatters = parser.parse(pattern, this.alwaysWriteExceptions);
133 }
134
135 public String getConversionPattern() {
136 return conversionPattern;
137 }
138
139 /**
140 * PatternLayout's content format is specified by:<p/>
141 * Key: "structured" Value: "false"<p/>
142 * Key: "formatType" Value: "conversion" (format uses the keywords supported by OptionConverter)<p/>
143 * Key: "format" Value: provided "conversionPattern" param
144 * @return Map of content format keys supporting PatternLayout
145 */
146 @Override
147 public Map<String, String> getContentFormat()
148 {
149 final Map<String, String> result = new HashMap<String, String>();
150 result.put("structured", "false");
151 result.put("formatType", "conversion");
152 result.put("format", conversionPattern);
153 return result;
154 }
155
156 /**
157 * Formats a logging event to a writer.
158 *
159 *
160 * @param event logging event to be formatted.
161 * @return The event formatted as a String.
162 */
163 @Override
164 public String toSerializable(final LogEvent event) {
165 final StringBuilder buf = new StringBuilder();
166 for (final PatternFormatter formatter : formatters) {
167 formatter.format(event, buf);
168 }
169 String str = buf.toString();
170 if (replace != null) {
171 str = replace.format(str);
172 }
173 return str;
174 }
175
176 /**
177 * Create a PatternParser.
178 * @param config The Configuration.
179 * @return The PatternParser.
180 */
181 public static PatternParser createPatternParser(final Configuration config) {
182 if (config == null) {
183 return new PatternParser(config, KEY, LogEventPatternConverter.class);
184 }
185 PatternParser parser = config.getComponent(KEY);
186 if (parser == null) {
187 parser = new PatternParser(config, KEY, LogEventPatternConverter.class);
188 config.addComponent(KEY, parser);
189 parser = (PatternParser) config.getComponent(KEY);
190 }
191 return parser;
192 }
193
194 @Override
195 public String toString() {
196 return conversionPattern;
197 }
198
199 /**
200 * Create a pattern layout.
201 *
202 * @param pattern The pattern. If not specified, defaults to DEFAULT_CONVERSION_PATTERN.
203 * @param config The Configuration. Some Converters require access to the Interpolator.
204 * @param replace A Regex replacement String.
205 * @param charsetName The character set.
206 * @param always If {@code "true"} (default) exceptions are always written even if the pattern contains no exception
207 * tokens.
208 * @return The PatternLayout.
209 */
210 @PluginFactory
211 public static PatternLayout createLayout(
212 @PluginAttribute("pattern") final String pattern,
213 @PluginConfiguration final Configuration config,
214 @PluginElement("Replace") final RegexReplacement replace,
215 @PluginAttribute("charset") final String charsetName,
216 @PluginAttribute("alwaysWriteExceptions") final String always) {
217 final Charset charset = Charsets.getSupportedCharset(charsetName);
218 final boolean alwaysWriteExceptions = Booleans.parseBoolean(always, true);
219 return new PatternLayout(
220 config, replace, pattern == null ? DEFAULT_CONVERSION_PATTERN : pattern, charset, alwaysWriteExceptions
221 );
222 }
223 }