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/WriterManager.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;

import java.io.IOException;
import java.io.Writer;
import java.util.concurrent.TimeUnit;

import org.apache.logging.log4j.core.StringLayout;

/**
 * Manages a Writer so that it can be shared by multiple Appenders and will
 * allow appenders to reconfigure without requiring a new writer.
 */
public class WriterManager extends AbstractManager {

    /**
     * Creates a Manager.
     *
     * @param name The name of the stream to manage.
     * @param data The data to pass to the Manager.
     * @param factory The factory to use to create the Manager.
     * @param <T> The type of the WriterManager.
     * @return A WriterManager.
     */
    public static <T> WriterManager getManager(final String name, final T data,
                                                 final ManagerFactory<? extends WriterManager, T> factory) {
        return AbstractManager.getManager(name, factory, data);
    }
    protected final StringLayout layout;

    private volatile Writer writer;

    public WriterManager(final Writer writer, final String streamName, final StringLayout layout,
            final boolean writeHeader) {
        super(null, streamName);
        this.writer = writer;
        this.layout = layout;
        if (writeHeader && layout != null) {
            final byte[] header = layout.getHeader();
            if (header != null) {
                try {
                    this.writer.write(new String(header, layout.getCharset()));
                } catch (final IOException e) {
                    logError("Unable to write header", e);
                }
            }
        }
    }

    protected synchronized void closeWriter() {
        final Writer w = writer; // access volatile field only once per method
        try {
            w.close();
        } catch (final IOException ex) {
            logError("Unable to close stream", ex);
        }
    }

    /**
     * Flushes any buffers.
     */
    public synchronized void flush() {
        try {
            writer.flush();
        } catch (final IOException ex) {
            final String msg = "Error flushing stream " + getName();
            throw new AppenderLoggingException(msg, ex);
        }
    }

    protected Writer getWriter() {
        return writer;
    }

    /**
     * Returns the status of the stream.
     * @return true if the stream is open, false if it is not.
     */
    public boolean isOpen() {
        return getCount() > 0;
    }

    /**
     * Default hook to write footer during close.
     */
    @Override
    public boolean releaseSub(final long timeout, final TimeUnit timeUnit) {
        writeFooter();
        closeWriter();
        return true;
    }

    protected void setWriter(final Writer writer) {
        final byte[] header = layout.getHeader();
        if (header != null) {
            try {
                writer.write(new String(header, layout.getCharset()));
                this.writer = writer; // only update field if writer.write() succeeded
            } catch (final IOException ioe) {
                logError("Unable to write header", ioe);
            }
        } else {
            this.writer = writer;
        }
    }

    /**
     * Some output streams synchronize writes while others do not. Synchronizing here insures that
     * log events won't be intertwined.
     * @param str the string to write
     * @throws AppenderLoggingException if an error occurs.
     */
    protected synchronized void write(final String str)  {
        try {
            writer.write(str);
        } catch (final IOException ex) {
            final String msg = "Error writing to stream " + getName();
            throw new AppenderLoggingException(msg, ex);
        }
    }

    /**
     * Writes the footer.
     */
    protected void writeFooter() {
        if (layout == null) {
            return;
        }
        final byte[] footer = layout.getFooter();
        if (footer != null && footer.length > 0) {
            write(new String(footer, layout.getCharset()));
        }
    }
}

⏎ org/apache/logging/log4j/core/appender/WriterManager.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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