Apache Log4j Core Implementation provides the functional components of the logging system. Users are free to create their own plugins and include them in the logging configuration. Apache Log4j Core is a required module to use Apache Log4j.

Bytecode (Java 8) for Apache Log4j Core Implementation is provided in a separate JAR file like log4j-core-2.14.1.jar.

Source Code files for Apache Log4j API are provided in both binary packge like apache-log4j-2.14.1-bin.zip and source package like apache-log4j-2.14.1-src.zip. You can download them at Apache Log4j Website.

You can also browse Source Code files for Apache Log4j Core Implementation 2.14.1 below.

⏎ org/apache/logging/log4j/core/pattern/LogEventPatternConverter.java

/*
 * 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.pattern;

import org.apache.logging.log4j.core.LogEvent;

/**
 * LoggingEventPatternConverter is a base class for pattern converters
 * that can format information from instances of LoggingEvent.
 */
public abstract class LogEventPatternConverter extends AbstractPatternConverter {

    /**
     * Constructs an instance of LoggingEventPatternConverter.
     *
     * @param name  name of converter.
     * @param style CSS style for output.
     */
    protected LogEventPatternConverter(final String name, final String style) {
        super(name, style);
    }

    /**
     * Formats an event into a string buffer.
     *
     * @param event      event to format, may not be null.
     * @param toAppendTo string buffer to which the formatted event will be appended.  May not be null.
     */
    public abstract void format(final LogEvent event, final StringBuilder toAppendTo);

    /**
     * {@inheritDoc}
     */
    @Override
    public void format(final Object obj, final StringBuilder output) {
        if (obj instanceof LogEvent) {
            format((LogEvent) obj, output);
        }
    }

    /**
     * Normally pattern converters are not meant to handle Exceptions although few pattern converters might.
     * <p>
     * By examining the return values for this method, the containing layout will determine whether it handles
     * throwables or not.
     * </p>
     *
     * @return true if this PatternConverter handles throwables
     */
    public boolean handlesThrowable() {
        return false;
    }

    public boolean isVariable() {
        return true;
    }
}

⏎ org/apache/logging/log4j/core/pattern/LogEventPatternConverter.java

Or download all of them as a single archive file:

File name: log4j-core-2.14.1-sources.jar
File size: 1281358 bytes
Release date: 2021-03-06
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