Apache Log4j API provides the interface that applications should code to and provides the adapter components required for implementers to create a logging implementation. Apache Log4j API is a required module to use Apache Log4j.

Bytecode (Java 8) for Apache Log4j API is provided in a separate JAR file like log4j-api-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 API 2.14.1 below.

⏎ org/apache/logging/log4j/internal/DefaultLogBuilder.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.internal;

import org.apache.logging.log4j.Level;
import org.apache.logging.log4j.LogBuilder;
import org.apache.logging.log4j.Logger;
import org.apache.logging.log4j.Marker;
import org.apache.logging.log4j.message.Message;
import org.apache.logging.log4j.message.SimpleMessage;
import org.apache.logging.log4j.status.StatusLogger;
import org.apache.logging.log4j.util.LambdaUtil;
import org.apache.logging.log4j.util.StackLocatorUtil;
import org.apache.logging.log4j.util.Supplier;


/**
 * Collects data for a log event and then logs it. This class should be considered private.
 */
public class DefaultLogBuilder implements LogBuilder {

    private static Message EMPTY_MESSAGE = new SimpleMessage("");
    private static final String FQCN = DefaultLogBuilder.class.getName();
    private static final Logger LOGGER = StatusLogger.getLogger();

    private final Logger logger;
    private Level level;
    private Marker marker;
    private Throwable throwable;
    private StackTraceElement location;
    private volatile boolean inUse;
    private long threadId;

    public DefaultLogBuilder(Logger logger, Level level) {
        this.logger = logger;
        this.level = level;
        this.threadId = Thread.currentThread().getId();
        this.inUse = true;
    }

    public DefaultLogBuilder(Logger logger) {
        this.logger = logger;
        this.inUse = false;
        this.threadId = Thread.currentThread().getId();
    }

    /**
     * This method should be considered internal. It is used to reset the LogBuilder for a new log message.
     * @param level The logging level for this event.
     * @return This LogBuilder instance.
     */
    public LogBuilder reset(Level level) {
        this.inUse = true;
        this.level = level;
        this.marker = null;
        this.throwable = null;
        this.location = null;
        return this;
    }

    @Override
    public LogBuilder withMarker(Marker marker) {
        this.marker = marker;
        return this;
    }

    @Override
    public LogBuilder withThrowable(Throwable throwable) {
        this.throwable = throwable;
        return this;
    }

    @Override
    public LogBuilder withLocation() {
        location = StackLocatorUtil.getStackTraceElement(2);
        return this;
    }

    @Override
    public LogBuilder withLocation(StackTraceElement location) {
        this.location = location;
        return this;
    }

    public boolean isInUse() {
        return inUse;
    }

    @Override
    public void log(Message message) {
        if (isValid()) {
            logMessage(message);
        }
    }

    @Override
    public void log(CharSequence message) {
        if (isValid()) {
            logMessage(logger.getMessageFactory().newMessage(message));
        }
    }

    @Override
    public void log(String message) {
        if (isValid()) {
            logMessage(logger.getMessageFactory().newMessage(message));
        }
    }

    @Override
    public void log(String message, Object... params) {
        if (isValid()) {
            logMessage(logger.getMessageFactory().newMessage(message, params));
        }
    }

    @Override
    public void log(String message, Supplier<?>... params) {
        if (isValid()) {
            logMessage(logger.getMessageFactory().newMessage(message, LambdaUtil.getAll(params)));
        }
    }

    @Override
    public void log(Supplier<Message> messageSupplier) {
        if (isValid()) {
            logMessage(messageSupplier.get());
        }
    }

    @Override
    public void log(Object message) {
        if (isValid()) {
            logMessage(logger.getMessageFactory().newMessage(message));
        }
    }

    @Override
    public void log(String message, Object p0) {
        if (isValid()) {
            logMessage(logger.getMessageFactory().newMessage(message, p0));
        }
    }

    @Override
    public void log(String message, Object p0, Object p1) {
        if (isValid()) {
            logMessage(logger.getMessageFactory().newMessage(message, p0, p1));
        }
    }

    @Override
    public void log(String message, Object p0, Object p1, Object p2) {
        if (isValid()) {
            logMessage(logger.getMessageFactory().newMessage(message, p0, p1, p2));
        }
    }

    @Override
    public void log(String message, Object p0, Object p1, Object p2, Object p3) {
        if (isValid()) {
            logMessage(logger.getMessageFactory().newMessage(message, p0, p1, p2, p3));
        }
    }

    @Override
    public void log(String message, Object p0, Object p1, Object p2, Object p3, Object p4) {
        if (isValid()) {
            logMessage(logger.getMessageFactory().newMessage(message, p0, p1, p2, p3, p4));
        }
    }

    @Override
    public void log(String message, Object p0, Object p1, Object p2, Object p3, Object p4, Object p5) {
        if (isValid()) {
            logMessage(logger.getMessageFactory().newMessage(message, p0, p1, p2, p3, p4, p5));
        }
    }

    @Override
    public void log(String message, Object p0, Object p1, Object p2, Object p3, Object p4, Object p5, Object p6) {
        if (isValid()) {
            logMessage(logger.getMessageFactory().newMessage(message, p0, p1, p2, p3, p4, p5, p6));
        }
    }

    @Override
    public void log(String message, Object p0, Object p1, Object p2, Object p3, Object p4, Object p5, Object p6,
            Object p7) {
        if (isValid()) {
            logMessage(logger.getMessageFactory().newMessage(message, p0, p1, p2, p3, p4, p5, p6, p7));
        }
    }

    @Override
    public void log(String message, Object p0, Object p1, Object p2, Object p3, Object p4, Object p5, Object p6,
            Object p7, Object p8) {
        if (isValid()) {
            logMessage(logger.getMessageFactory().newMessage(message, p0, p1, p2, p3, p4, p5, p6, p7, p8));
        }
    }

    @Override
    public void log(String message, Object p0, Object p1, Object p2, Object p3, Object p4, Object p5, Object p6,
            Object p7, Object p8, Object p9) {
        if (isValid()) {
            logMessage(logger.getMessageFactory().newMessage(message, p0, p1, p2, p3, p4, p5, p6, p7, p8, p9));
        }
    }

    @Override
    public void log() {
        if (isValid()) {
            logMessage(EMPTY_MESSAGE);
        }
    }

    private void logMessage(Message message) {
        try {
            logger.logMessage(level, marker, FQCN, location, message, throwable);
        } finally {
            inUse = false;
        }
    }

    private boolean isValid() {
        if (!inUse) {
            LOGGER.warn("Attempt to reuse LogBuilder was ignored. {}",
                    StackLocatorUtil.getCallerClass(2));
            return false ;
        }
        if (this.threadId != Thread.currentThread().getId()) {
            LOGGER.warn("LogBuilder can only be used on the owning thread. {}",
                    StackLocatorUtil.getCallerClass(2));
            return false;
        }
        return true;
    }
}

⏎ org/apache/logging/log4j/internal/DefaultLogBuilder.java

Or download all of them as a single archive file:

File name: log4j-api-2.14.1-sources.jar
File size: 264773 bytes
Release date: 2021-03-06
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