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/DateParser.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.ParseException;
import java.text.ParsePosition;
import java.util.Calendar;
import java.util.Date;
import java.util.Locale;
import java.util.TimeZone;

/**
 * DateParser is the "missing" interface for the parsing 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>
 * 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 DateParser {

    /**
     * Equivalent to DateFormat.parse(String).
     *
     * See {@link java.text.DateFormat#parse(String)} for more information.
     * @param source A <code>String</code> whose beginning should be parsed.
     * @return A <code>Date</code> parsed from the string
     * @throws ParseException if the beginning of the specified string cannot be parsed.
     */
    Date parse(String source) throws ParseException;

    /**
     * Equivalent to DateFormat.parse(String, ParsePosition).
     *
     * See {@link java.text.DateFormat#parse(String, ParsePosition)} for more information.
     *
     * @param source A <code>String</code>, part of which should be parsed.
     * @param pos A <code>ParsePosition</code> object with index and error index information
     * as described above.
     * @return A <code>Date</code> parsed from the string. In case of error, returns null.
     * @throws NullPointerException if text or pos is null.
     */
    Date parse(String source, ParsePosition pos);

    /**
     * Parses a formatted date string according to the format.  Updates the Calendar with parsed fields.
     * Upon success, the ParsePosition index is updated to indicate how much of the source text was consumed.
     * Not all source text needs to be consumed.  Upon parse failure, ParsePosition error index is updated to
     * the offset of the source text which does not match the supplied format.
     *
     * @param source The text to parse.
     * @param pos On input, the position in the source to start parsing, on output, updated position.
     * @param calendar The calendar into which to set parsed fields.
     * @return true, if source has been parsed (pos parsePosition is updated); otherwise false (and pos errorIndex is updated)
     * @throws IllegalArgumentException when Calendar has been set to be not lenient, and a parsed field is
     * out of range.
     *
     * @since 3.5
     */
    boolean parse(String source, ParsePosition pos, Calendar calendar);

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

    /**
     * <p>
     * Gets the time zone used by this parser.
     * </p>
     *
     * <p>
     * The default {@link TimeZone} used to create a {@link Date} when the {@link TimeZone} is not specified by
     * the format pattern.
     * </p>
     *
     * @return the time zone
     */
    TimeZone getTimeZone();

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

    /**
     * Parses text from a string to produce a Date.
     *
     * @param source A <code>String</code> whose beginning should be parsed.
     * @return a <code>java.util.Date</code> object
     * @throws ParseException if the beginning of the specified string cannot be parsed.
     * @see java.text.DateFormat#parseObject(String)
     */
    Object parseObject(String source) throws ParseException;

    /**
     * Parses a date/time string according to the given parse position.
     *
     * @param source A <code>String</code> whose beginning should be parsed.
     * @param pos the parse position
     * @return a <code>java.util.Date</code> object
     * @see java.text.DateFormat#parseObject(String, ParsePosition)
     */
    Object parseObject(String source, ParsePosition pos);
}

⏎ org/apache/logging/log4j/core/util/datetime/DateParser.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
Download 

⇒ Source Code for Apache Log4j JDK Logging Adapter

⇐ Source Code for Apache Log4j API

⇑ Downloading and Reviewing Apache Log4j Packages

⇑⇑ FAQ for Apache Log4j