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/util/datetime/DatePrinter.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.util.datetime;

import java.text.FieldPosition;
import java.util.Calendar;
import java.util.Date;
import java.util.Locale;
import java.util.TimeZone;

/**
 * DatePrinter is the "missing" interface for the format methods of
 * {@link java.text.DateFormat}. You can obtain an object implementing this
 * interface by using one of the FastDateFormat factory methods.
 * <p>
 * Warning: Since binary compatible methods may be added to this interface in any
 * release, developers are not expected to implement this interface.
 * </p>
 *
 * <p>
 * Copied and modified from <a href="https://commons.apache.org/proper/commons-lang/">Apache Commons Lang</a>.
 * </p>
 *
 * @since Apache Commons Lang 3.2
 */
public interface DatePrinter {

    /**
     * <p>Formats a millisecond {@code long} value.</p>
     *
     * @param millis  the millisecond value to format
     * @return the formatted string
     * @since 2.1
     */
    String format(long millis);

    /**
     * <p>Formats a {@code Date} object using a {@code GregorianCalendar}.</p>
     *
     * @param date  the date to format
     * @return the formatted string
     */
    String format(Date date);

    /**
     * <p>Formats a {@code Calendar} object.</p>
     * The TimeZone set on the Calendar is only used to adjust the time offset.
     * The TimeZone specified during the construction of the Parser will determine the TimeZone
     * used in the formatted string.
     *
     * @param calendar  the calendar to format.
     * @return the formatted string
     */
    String format(Calendar calendar);

    /**
     * <p>Formats a millisecond {@code long} value into the
     * supplied {@code Appendable}.</p>
     *
     * @param millis  the millisecond value to format
     * @param buf  the buffer to format into
     * @param <B> the Appendable class type, usually StringBuilder or StringBuffer.
     * @return the specified string buffer
     * @since 3.5
     */
    <B extends Appendable> B format(long millis, B buf);

    /**
     * <p>Formats a {@code Date} object into the
     * supplied {@code Appendable} using a {@code GregorianCalendar}.</p>
     *
     * @param date  the date to format
     * @param buf  the buffer to format into
     * @param <B> the Appendable class type, usually StringBuilder or StringBuffer.
     * @return the specified string buffer
     * @since 3.5
     */
    <B extends Appendable> B format(Date date, B buf);

    /**
     * <p>Formats a {@code Calendar} object into the supplied {@code Appendable}.</p>
     * The TimeZone set on the Calendar is only used to adjust the time offset.
     * The TimeZone specified during the construction of the Parser will determine the TimeZone
     * used in the formatted string.
     *
     * @param calendar  the calendar to format
     * @param buf  the buffer to format into
     * @param <B> the Appendable class type, usually StringBuilder or StringBuffer.
     * @return the specified string buffer
     * @since 3.5
     */
    <B extends Appendable> B format(Calendar calendar, B buf);


    // Accessors
    //-----------------------------------------------------------------------
    /**
     * <p>Gets the pattern used by this printer.</p>
     *
     * @return the pattern, {@link java.text.SimpleDateFormat} compatible
     */
    String getPattern();

    /**
     * <p>Gets the time zone used by this printer.</p>
     *
     * <p>This zone is always used for {@code Date} printing. </p>
     *
     * @return the time zone
     */
    TimeZone getTimeZone();

    /**
     * <p>Gets the locale used by this printer.</p>
     *
     * @return the locale
     */
    Locale getLocale();

    /**
     * <p>Formats a {@code Date}, {@code Calendar} or
     * {@code Long} (milliseconds) object.</p>
     *
     * @param obj  the object to format
     * @param toAppendTo  the buffer to append to
     * @param pos  the position - ignored
     * @return the buffer passed in
     * @see java.text.DateFormat#format(Object, StringBuffer, FieldPosition)
     */
    StringBuilder format(Object obj, StringBuilder toAppendTo, FieldPosition pos);
}

⏎ org/apache/logging/log4j/core/util/datetime/DatePrinter.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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