org.apache.log4j.pattern.Log4j1MdcPatternConverter Maven / Gradle / Ivy
/*
* 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.log4j.pattern;
import org.apache.logging.log4j.core.LogEvent;
import org.apache.logging.log4j.core.config.plugins.Plugin;
import org.apache.logging.log4j.core.pattern.ConverterKeys;
import org.apache.logging.log4j.core.pattern.LogEventPatternConverter;
import org.apache.logging.log4j.core.pattern.PatternConverter;
import org.apache.logging.log4j.util.TriConsumer;
/**
* Able to handle the contents of the LogEvent's MDC and either
* output the entire contents of the properties, or to output the value of a specific key
* within the property bundle when this pattern converter has the option set.
*/
@Plugin(name = "Log4j1MdcPatternConverter", category = PatternConverter.CATEGORY)
@ConverterKeys({ "properties" })
public final class Log4j1MdcPatternConverter extends LogEventPatternConverter {
/**
* Name of property to output.
*/
private final String key;
/**
* Private constructor.
*
* @param options options, may be null.
*/
private Log4j1MdcPatternConverter(final String[] options) {
super(options != null && options.length > 0 ? "Log4j1MDC{" + options[0] + '}' : "Log4j1MDC", "property");
if (options != null && options.length > 0) {
key = options[0];
} else {
key = null;
}
}
/**
* Obtains an instance of PropertiesPatternConverter.
*
* @param options options, may be null or first element contains name of property to format.
* @return instance of PropertiesPatternConverter.
*/
public static Log4j1MdcPatternConverter newInstance(final String[] options) {
return new Log4j1MdcPatternConverter(options);
}
/**
* {@inheritDoc}
*/
@Override
public void format(final LogEvent event, final StringBuilder toAppendTo) {
if (key == null) {
// if there is no additional options, we output every single Key/Value pair for the MDC
toAppendTo.append('{');
event.getContextData().forEach(APPEND_EACH, toAppendTo);
toAppendTo.append('}');
} else {
// otherwise they just want a single key output
final Object val = event.getContextData().getValue(key);
if (val != null) {
toAppendTo.append(val);
}
}
}
private static TriConsumer APPEND_EACH = (key, value, toAppendTo) -> toAppendTo.append('{').append(key).append(',').append(value).append('}');
}