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/MessagePatternConverter.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 java.util.Locale;

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.util.ArrayUtils;
import org.apache.logging.log4j.core.util.Constants;
import org.apache.logging.log4j.core.util.Loader;
import org.apache.logging.log4j.message.Message;
import org.apache.logging.log4j.message.MultiformatMessage;
import org.apache.logging.log4j.status.StatusLogger;
import org.apache.logging.log4j.util.MultiFormatStringBuilderFormattable;
import org.apache.logging.log4j.util.PerformanceSensitive;
import org.apache.logging.log4j.util.StringBuilderFormattable;

/**
 * Returns the event's rendered message in a StringBuilder.
 */
@Plugin(name = "MessagePatternConverter", category = PatternConverter.CATEGORY)
@ConverterKeys({ "m", "msg", "message" })
@PerformanceSensitive("allocation")
public final class MessagePatternConverter extends LogEventPatternConverter {

    private static final String NOLOOKUPS = "nolookups";

    private final String[] formats;
    private final Configuration config;
    private final TextRenderer textRenderer;
    private final boolean noLookups;

    /**
     * Private constructor.
     *
     * @param options
     *            options, may be null.
     */
    private MessagePatternConverter(final Configuration config, final String[] options) {
        super("Message", "message");
        this.formats = options;
        this.config = config;
        final int noLookupsIdx = loadNoLookups(options);
        this.noLookups = Constants.FORMAT_MESSAGES_PATTERN_DISABLE_LOOKUPS || noLookupsIdx >= 0;
        this.textRenderer = loadMessageRenderer(noLookupsIdx >= 0 ? ArrayUtils.remove(options, noLookupsIdx) : options);
    }

    private int loadNoLookups(final String[] options) {
        if (options != null) {
            for (int i = 0; i < options.length; i++) {
                final String option = options[i];
                if (NOLOOKUPS.equalsIgnoreCase(option)) {
                    return i;
                }
            }
        }
        return -1;
    }

    private TextRenderer loadMessageRenderer(final String[] options) {
        if (options != null) {
            for (final String option : options) {
                switch (option.toUpperCase(Locale.ROOT)) {
                case "ANSI":
                    if (Loader.isJansiAvailable()) {
                        return new JAnsiTextRenderer(options, JAnsiTextRenderer.DefaultMessageStyleMap);
                    }
                    StatusLogger.getLogger()
                            .warn("You requested ANSI message rendering but JANSI is not on the classpath.");
                    return null;
                case "HTML":
                    return new HtmlTextRenderer(options);
                }
            }
        }
        return null;
    }

    /**
     * Obtains an instance of pattern converter.
     *
     * @param config
     *            The Configuration.
     * @param options
     *            options, may be null.
     * @return instance of pattern converter.
     */
    public static MessagePatternConverter newInstance(final Configuration config, final String[] options) {
        return new MessagePatternConverter(config, options);
    }

    /**
     * {@inheritDoc}
     */
    @Override
    public void format(final LogEvent event, final StringBuilder toAppendTo) {
        final Message msg = event.getMessage();
        if (msg instanceof StringBuilderFormattable) {

            final boolean doRender = textRenderer != null;
            final StringBuilder workingBuilder = doRender ? new StringBuilder(80) : toAppendTo;

            final int offset = workingBuilder.length();
            if (msg instanceof MultiFormatStringBuilderFormattable) {
                ((MultiFormatStringBuilderFormattable) msg).formatTo(formats, workingBuilder);
            } else {
                ((StringBuilderFormattable) msg).formatTo(workingBuilder);
            }

            // TODO can we optimize this?
            if (config != null && !noLookups) {
                for (int i = offset; i < workingBuilder.length() - 1; i++) {
                    if (workingBuilder.charAt(i) == '$' && workingBuilder.charAt(i + 1) == '{') {
                        final String value = workingBuilder.substring(offset, workingBuilder.length());
                        workingBuilder.setLength(offset);
                        workingBuilder.append(config.getStrSubstitutor().replace(event, value));
                    }
                }
            }
            if (doRender) {
                textRenderer.render(workingBuilder, toAppendTo);
            }
            return;
        }
        if (msg != null) {
            String result;
            if (msg instanceof MultiformatMessage) {
                result = ((MultiformatMessage) msg).getFormattedMessage(formats);
            } else {
                result = msg.getFormattedMessage();
            }
            if (result != null) {
                toAppendTo.append(config != null && result.contains("${")
                        ? config.getStrSubstitutor().replace(event, result) : result);
            } else {
                toAppendTo.append("null");
            }
        }
    }
}

⏎ org/apache/logging/log4j/core/pattern/MessagePatternConverter.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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