/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You under the Apache license, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the license for the specific language governing permissions and
* limitations under the license.
*/
package org.apache.logging.log4j.core.layout;
import org.apache.logging.log4j.core.LogEvent;
import org.apache.logging.log4j.core.config.Configuration;
import org.apache.logging.log4j.core.config.plugins.Plugin;
import org.apache.logging.log4j.core.config.plugins.PluginAttr;
import org.apache.logging.log4j.core.config.plugins.PluginConfiguration;
import org.apache.logging.log4j.core.config.plugins.PluginElement;
import org.apache.logging.log4j.core.config.plugins.PluginFactory;
import org.apache.logging.log4j.core.helpers.OptionConverter;
import org.apache.logging.log4j.core.pattern.LogEventPatternConverter;
import org.apache.logging.log4j.core.pattern.PatternFormatter;
import org.apache.logging.log4j.core.pattern.PatternParser;
import org.apache.logging.log4j.core.pattern.RegexReplacement;
import java.nio.charset.Charset;
import java.util.List;
/**
* <p>A flexible layout configurable with pattern string. The goal of this class
* is to {@link #format format} a {@link LogEvent} and return the results.
* The format of the result depends on the <em>conversion pattern</em>.
* <p>
* <p/>
* <p>The conversion pattern is closely related to the conversion
* pattern of the printf function in C. A conversion pattern is
* composed of literal text and format control expressions called
* <em>conversion specifiers</em>.
*
* See the Log4j Manual for details on the supported pattern converters.
*/
@Plugin(name = "PatternLayout", type = "Core", elementType = "layout", printObject = true)
public final class PatternLayout extends AbstractStringLayout {
/**
* Default pattern string for log output. Currently set to the
* string <b>"%m%n"</b> which just prints the application supplied
* message.
*/
public static final String DEFAULT_CONVERSION_PATTERN = "%m%n";
/**
* A conversion pattern equivalent to the TTCCCLayout.
* Current value is <b>%r [%t] %p %c %x - %m%n</b>.
*/
public static final String TTCC_CONVERSION_PATTERN =
"%r [%t] %p %c %x - %m%n";
/**
* A simple pattern.
* Current value is <b>%d [%t] %p %c - %m%n</b>.
*/
public static final String SIMPLE_CONVERSION_PATTERN =
"%d [%t] %p %c - %m%n";
private static final String KEY = "Converter";
/**
* Initial converter for pattern.
*/
private List<PatternFormatter> formatters;
/**
* Conversion pattern.
*/
private String conversionPattern;
/**
* True if any element in pattern formats information from exceptions.
*/
private boolean handlesExceptions;
/**
* The current Configuration.
*/
private final Configuration config;
private final RegexReplacement replace;
/**
* Constructs a EnhancedPatternLayout using the supplied conversion pattern.
*
* @param config The Configuration.
* @param replace The regular expression to match.
* @param pattern conversion pattern.
* @param charset The character set.
*/
private PatternLayout(Configuration config, final RegexReplacement replace, final String pattern,
final Charset charset) {
super(charset);
this.replace = replace;
this.conversionPattern = pattern;
this.config = config;
PatternParser parser = createPatternParser(config);
formatters = parser.parse((pattern == null) ? DEFAULT_CONVERSION_PATTERN : pattern);
handlesExceptions = parser.handlesExceptions();
}
/**
* Set the <b>ConversionPattern</b> option. This is the string which
* controls formatting and consists of a mix of literal content and
* conversion specifiers.
*
* @param conversionPattern conversion pattern.
*/
public void setConversionPattern(final String conversionPattern) {
String pattern = OptionConverter.convertSpecialChars(conversionPattern);
if (pattern == null) {
return;
}
PatternParser parser = createPatternParser(this.config);
formatters = parser.parse(pattern);
handlesExceptions = parser.handlesExceptions();
}
/**
* Formats a logging event to a writer.
*
* @param event logging event to be formatted.
* @return The event formatted as a String.
*/
public String formatAs(final LogEvent event) {
StringBuilder buf = new StringBuilder();
for (PatternFormatter formatter : formatters) {
formatter.format(event, buf);
}
String str = buf.toString();
if (replace != null) {
str = replace.format(str);
}
return config == null ? str : config.getSubst().replace(event, str);
}
/**
* Create a PatternParser.
* @param config The Configuration.
* @return The PatternParser.
*/
public static PatternParser createPatternParser(Configuration config) {
if (config == null) {
return new PatternParser(config, KEY, LogEventPatternConverter.class);
}
PatternParser parser = (PatternParser) config.getComponent(KEY);
if (parser == null) {
parser = new PatternParser(config, KEY, LogEventPatternConverter.class);
config.addComponent(KEY, parser);
parser = (PatternParser) config.getComponent(KEY);
}
return parser;
}
@Override
public String toString() {
return conversionPattern;
}
/**
* Create a pattern layout.
* @param pattern The pattern. If not specified, defaults to DEFAULT_CONVERSION_PATTERN.
* @param config The Configuration. Some Converters require access to the Interpolator.
* @param replace A Regex replacement String.
* @param charset The character set.
* @return The PatternLayout.
*/
@PluginFactory
public static PatternLayout createLayout(@PluginAttr("pattern") String pattern,
@PluginConfiguration Configuration config,
@PluginElement("replace") RegexReplacement replace,
@PluginAttr("charset") String charset) {
Charset c = Charset.isSupported("UTF-8") ? Charset.forName("UTF-8") : Charset.defaultCharset();
if (charset != null) {
if (Charset.isSupported(charset)) {
c = Charset.forName(charset);
} else {
LOGGER.error("Charset " + charset + " is not supported for layout, using " + c.displayName());
}
}
return new PatternLayout(config, replace, pattern == null ? DEFAULT_CONVERSION_PATTERN : pattern, c);
}
}