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/filter/ThresholdFilter.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.filter;

import org.apache.logging.log4j.Level;
import org.apache.logging.log4j.Marker;
import org.apache.logging.log4j.core.Filter;
import org.apache.logging.log4j.core.LogEvent;
import org.apache.logging.log4j.core.Logger;
import org.apache.logging.log4j.core.config.Node;
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.PluginFactory;
import org.apache.logging.log4j.message.Message;
import org.apache.logging.log4j.util.PerformanceSensitive;

/**
 * This filter returns the onMatch result if the level in the LogEvent is the same or more specific
 * than the configured level and the onMismatch value otherwise. For example, if the ThresholdFilter
 * is configured with Level ERROR and the LogEvent contains Level DEBUG then the onMismatch value will
 * be returned since ERROR events are more specific than DEBUG.
 *
 * The default Level is ERROR.
 */
@Plugin(name = "ThresholdFilter", category = Node.CATEGORY, elementType = Filter.ELEMENT_TYPE, printObject = true)
@PerformanceSensitive("allocation")
public final class ThresholdFilter extends AbstractFilter {

    private final Level level;

    private ThresholdFilter(final Level level, final Result onMatch, final Result onMismatch) {
        super(onMatch, onMismatch);
        this.level = level;
    }

    @Override
    public Result filter(final Logger logger, final Level testLevel, final Marker marker, final String msg,
                         final Object... params) {
        return filter(testLevel);
    }

    @Override
    public Result filter(final Logger logger, final Level testLevel, final Marker marker, final Object msg,
                         final Throwable t) {
        return filter(testLevel);
    }

    @Override
    public Result filter(final Logger logger, final Level testLevel, final Marker marker, final Message msg,
                         final Throwable t) {
        return filter(testLevel);
    }

    @Override
    public Result filter(final LogEvent event) {
        return filter(event.getLevel());
    }

    private Result filter(final Level testLevel) {
        return testLevel.isMoreSpecificThan(this.level) ? onMatch : onMismatch;
    }

    @Override
    public Result filter(final Logger logger, final Level level, final Marker marker, final String msg,
            final Object p0) {
        return filter(level);
    }

    @Override
    public Result filter(final Logger logger, final Level level, final Marker marker, final String msg,
            final Object p0, final Object p1) {
        return filter(level);
    }

    @Override
    public Result filter(final Logger logger, final Level level, final Marker marker, final String msg,
            final Object p0, final Object p1, final Object p2) {
        return filter(level);
    }

    @Override
    public Result filter(final Logger logger, final Level level, final Marker marker, final String msg,
            final Object p0, final Object p1, final Object p2, final Object p3) {
        return filter(level);
    }

    @Override
    public Result filter(final Logger logger, final Level level, final Marker marker, final String msg,
            final Object p0, final Object p1, final Object p2, final Object p3,
            final Object p4) {
        return filter(level);
    }

    @Override
    public Result filter(final Logger logger, final Level level, final Marker marker, final String msg,
            final Object p0, final Object p1, final Object p2, final Object p3,
            final Object p4, final Object p5) {
        return filter(level);
    }

    @Override
    public Result filter(final Logger logger, final Level level, final Marker marker, final String msg,
            final Object p0, final Object p1, final Object p2, final Object p3,
            final Object p4, final Object p5, final Object p6) {
        return filter(level);
    }

    @Override
    public Result filter(final Logger logger, final Level level, final Marker marker, final String msg,
            final Object p0, final Object p1, final Object p2, final Object p3,
            final Object p4, final Object p5, final Object p6,
            final Object p7) {
        return filter(level);
    }

    @Override
    public Result filter(final Logger logger, final Level level, final Marker marker, final String msg,
            final Object p0, final Object p1, final Object p2, final Object p3,
            final Object p4, final Object p5, final Object p6,
            final Object p7, final Object p8) {
        return filter(level);
    }

    @Override
    public Result filter(final Logger logger, final Level level, final Marker marker, final String msg,
            final Object p0, final Object p1, final Object p2, final Object p3,
            final Object p4, final Object p5, final Object p6,
            final Object p7, final Object p8, final Object p9) {
        return filter(level);
    }

    public Level getLevel() {
        return level;
    }

    @Override
    public String toString() {
        return level.toString();
    }

    /**
     * Creates a ThresholdFilter.
     * @param level The log Level.
     * @param match The action to take on a match.
     * @param mismatch The action to take on a mismatch.
     * @return The created ThresholdFilter.
     */
    // TODO Consider refactoring to use AbstractFilter.AbstractFilterBuilder
    @PluginFactory
    public static ThresholdFilter createFilter(
            @PluginAttribute("level") final Level level,
            @PluginAttribute("onMatch") final Result match,
            @PluginAttribute("onMismatch") final Result mismatch) {
        final Level actualLevel = level == null ? Level.ERROR : level;
        final Result onMatch = match == null ? Result.NEUTRAL : match;
        final Result onMismatch = mismatch == null ? Result.DENY : mismatch;
        return new ThresholdFilter(actualLevel, onMatch, onMismatch);
    }

}

⏎ org/apache/logging/log4j/core/filter/ThresholdFilter.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