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/appender/rolling/CronTriggeringPolicy.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.appender.rolling;

import java.text.ParseException;
import java.util.Date;
import java.util.Objects;
import java.util.concurrent.TimeUnit;

import org.apache.logging.log4j.core.Core;
import org.apache.logging.log4j.core.LogEvent;
import org.apache.logging.log4j.core.config.Configuration;
import org.apache.logging.log4j.core.config.ConfigurationScheduler;
import org.apache.logging.log4j.core.config.CronScheduledFuture;
import org.apache.logging.log4j.core.config.Scheduled;
import org.apache.logging.log4j.core.config.plugins.Plugin;
import org.apache.logging.log4j.core.config.plugins.PluginAttribute;
import org.apache.logging.log4j.core.config.plugins.PluginConfiguration;
import org.apache.logging.log4j.core.config.plugins.PluginFactory;
import org.apache.logging.log4j.core.util.CronExpression;

/**
 * Rolls a file over based on a cron schedule.
 */
@Plugin(name = "CronTriggeringPolicy", category = Core.CATEGORY_NAME, printObject = true)
@Scheduled
public final class CronTriggeringPolicy extends AbstractTriggeringPolicy {

    private static final String defaultSchedule = "0 0 0 * * ?";
    private RollingFileManager manager;
    private final CronExpression cronExpression;
    private final Configuration configuration;
    private final boolean checkOnStartup;
    private volatile Date lastRollDate;
    private CronScheduledFuture<?> future;

    private CronTriggeringPolicy(final CronExpression schedule, final boolean checkOnStartup,
            final Configuration configuration) {
        this.cronExpression = Objects.requireNonNull(schedule, "schedule");
        this.configuration = Objects.requireNonNull(configuration, "configuration");
        this.checkOnStartup = checkOnStartup;
    }

    /**
     * Initializes the policy.
     *
     * @param aManager
     *            The RollingFileManager.
     */
    @Override
    public void initialize(final RollingFileManager aManager) {
        this.manager = aManager;
        final Date now = new Date();
        final Date lastRollForFile = cronExpression.getPrevFireTime(new Date(this.manager.getFileTime()));
        final Date lastRegularRoll = cronExpression.getPrevFireTime(new Date());
        aManager.getPatternProcessor().setCurrentFileTime(lastRegularRoll.getTime());
        LOGGER.debug("LastRollForFile {}, LastRegularRole {}", lastRollForFile, lastRegularRoll);
        aManager.getPatternProcessor().setPrevFileTime(lastRegularRoll.getTime());
        aManager.getPatternProcessor().setTimeBased(true);
        if (checkOnStartup && lastRollForFile != null && lastRegularRoll != null &&
                lastRollForFile.before(lastRegularRoll)) {
            lastRollDate = lastRollForFile;
            rollover();
        }

        final ConfigurationScheduler scheduler = configuration.getScheduler();
        if (!scheduler.isExecutorServiceSet()) {
            // make sure we have a thread pool
            scheduler.incrementScheduledItems();
        }
        if (!scheduler.isStarted()) {
            scheduler.start();
        }
        lastRollDate = lastRegularRoll;
        future = scheduler.scheduleWithCron(cronExpression, now, new CronTrigger());
        LOGGER.debug(scheduler.toString());
    }

    /**
     * Determines whether a rollover should occur.
     *
     * @param event
     *            A reference to the currently event.
     * @return true if a rollover should occur.
     */
    @Override
    public boolean isTriggeringEvent(final LogEvent event) {
        return false;
    }

    public CronExpression getCronExpression() {
        return cronExpression;
    }

    /**
     * Creates a ScheduledTriggeringPolicy.
     *
     * @param configuration
     *            the Configuration.
     * @param evaluateOnStartup
     *            check if the file should be rolled over immediately.
     * @param schedule
     *            the cron expression.
     * @return a ScheduledTriggeringPolicy.
     */
    @PluginFactory
    public static CronTriggeringPolicy createPolicy(@PluginConfiguration final Configuration configuration,
            @PluginAttribute("evaluateOnStartup") final String evaluateOnStartup,
            @PluginAttribute("schedule") final String schedule) {
        CronExpression cronExpression;
        final boolean checkOnStartup = Boolean.parseBoolean(evaluateOnStartup);
        if (schedule == null) {
            LOGGER.info("No schedule specified, defaulting to Daily");
            cronExpression = getSchedule(defaultSchedule);
        } else {
            cronExpression = getSchedule(schedule);
            if (cronExpression == null) {
                LOGGER.error("Invalid expression specified. Defaulting to Daily");
                cronExpression = getSchedule(defaultSchedule);
            }
        }
        return new CronTriggeringPolicy(cronExpression, checkOnStartup, configuration);
    }

    private static CronExpression getSchedule(final String expression) {
        try {
            return new CronExpression(expression);
        } catch (final ParseException pe) {
            LOGGER.error("Invalid cron expression - " + expression, pe);
            return null;
        }
    }

    private void rollover() {
    	manager.rollover(cronExpression.getPrevFireTime(new Date()), lastRollDate);
        if (future != null) {
            lastRollDate = future.getFireTime();
        }
    }

    @Override
    public boolean stop(final long timeout, final TimeUnit timeUnit) {
        setStopping();
        final boolean stopped = stop(future);
        setStopped();
        return stopped;
    }

    @Override
    public String toString() {
        return "CronTriggeringPolicy(schedule=" + cronExpression.getCronExpression() + ")";
    }

    private class CronTrigger implements Runnable {

        @Override
        public void run() {
            rollover();
        }
    }
}

⏎ org/apache/logging/log4j/core/appender/rolling/CronTriggeringPolicy.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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