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/AbstractOutputStreamAppender.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.Serializable;
import java.util.concurrent.TimeUnit;

import org.apache.logging.log4j.core.Filter;
import org.apache.logging.log4j.core.Layout;
import org.apache.logging.log4j.core.LogEvent;
import org.apache.logging.log4j.core.config.Property;
import org.apache.logging.log4j.core.config.plugins.PluginBuilderAttribute;
import org.apache.logging.log4j.core.util.Constants;

/**
 * Appends log events as bytes to a byte output stream. The stream encoding is defined in the layout.
 *
 * @param <M> The kind of {@link OutputStreamManager} under management
 */
public abstract class AbstractOutputStreamAppender<M extends OutputStreamManager> extends AbstractAppender {

    /**
     * Subclasses can extend this abstract Builder.
     *
     * @param <B> The type to build.
     */
    public abstract static class Builder<B extends Builder<B>> extends AbstractAppender.Builder<B> {

        @PluginBuilderAttribute
        private boolean bufferedIo = true;

        @PluginBuilderAttribute
        private int bufferSize = Constants.ENCODER_BYTE_BUFFER_SIZE;

        @PluginBuilderAttribute
        private boolean immediateFlush = true;

        public int getBufferSize() {
            return bufferSize;
        }

        public boolean isBufferedIo() {
            return bufferedIo;
        }

        public boolean isImmediateFlush() {
            return immediateFlush;
        }

        public B withImmediateFlush(final boolean immediateFlush) {
            this.immediateFlush = immediateFlush;
            return asBuilder();
        }

        public B withBufferedIo(final boolean bufferedIo) {
            this.bufferedIo = bufferedIo;
            return asBuilder();
        }

        public B withBufferSize(final int bufferSize) {
            this.bufferSize = bufferSize;
            return asBuilder();
        }

    }

    /**
     * Immediate flush means that the underlying writer or output stream will be flushed at the end of each append
     * operation. Immediate flush is slower but ensures that each append request is actually written. If
     * <code>immediateFlush</code> is set to {@code false}, then there is a good chance that the last few logs events
     * are not actually written to persistent media if and when the application crashes.
     */
    private final boolean immediateFlush;

    private final M manager;

    /**
     * Instantiates a WriterAppender and set the output destination to a new {@link java.io.OutputStreamWriter}
     * initialized with <code>os</code> as its {@link java.io.OutputStream}.
     *
     * @param name The name of the Appender.
     * @param layout The layout to format the message.
     * @param manager The OutputStreamManager.
     * @deprecated Use {@link #AbstractOutputStreamAppender(String, Layout, Filter, boolean, boolean, Property[], OutputStreamManager)}
     */
    @Deprecated
    protected AbstractOutputStreamAppender(final String name, final Layout<? extends Serializable> layout,
            final Filter filter, final boolean ignoreExceptions, final boolean immediateFlush, final M manager) {
        super(name, filter, layout, ignoreExceptions, Property.EMPTY_ARRAY);
        this.manager = manager;
        this.immediateFlush = immediateFlush;
    }

    /**
     * Instantiates a WriterAppender and set the output destination to a new {@link java.io.OutputStreamWriter}
     * initialized with <code>os</code> as its {@link java.io.OutputStream}.
     *
     * @param name The name of the Appender.
     * @param layout The layout to format the message.
     * @param properties optional properties
     * @param manager The OutputStreamManager.
     */
    protected AbstractOutputStreamAppender(final String name, final Layout<? extends Serializable> layout,
            final Filter filter, final boolean ignoreExceptions, final boolean immediateFlush,
            final Property[] properties, final M manager) {
        super(name, filter, layout, ignoreExceptions, properties);
        this.manager = manager;
        this.immediateFlush = immediateFlush;
    }

    /**
     * Gets the immediate flush setting.
     *
     * @return immediate flush.
     */
    public boolean getImmediateFlush() {
        return immediateFlush;
    }

    /**
     * Gets the manager.
     *
     * @return the manager.
     */
    public M getManager() {
        return manager;
    }

    @Override
    public void start() {
        if (getLayout() == null) {
            LOGGER.error("No layout set for the appender named [" + getName() + "].");
        }
        if (manager == null) {
            LOGGER.error("No OutputStreamManager set for the appender named [" + getName() + "].");
        }
        super.start();
    }

    @Override
    public boolean stop(final long timeout, final TimeUnit timeUnit) {
        return stop(timeout, timeUnit, true);
    }

    @Override
    protected boolean stop(final long timeout, final TimeUnit timeUnit, final boolean changeLifeCycleState) {
        boolean stopped = super.stop(timeout, timeUnit, changeLifeCycleState);
        stopped &= manager.stop(timeout, timeUnit);
        if (changeLifeCycleState) {
            setStopped();
        }
        LOGGER.debug("Appender {} stopped with status {}", getName(), stopped);
        return stopped;
    }

    /**
     * Actual writing occurs here.
     * <p>
     * Most subclasses of <code>AbstractOutputStreamAppender</code> will need to override this method.
     * </p>
     *
     * @param event The LogEvent.
     */
    @Override
    public void append(final LogEvent event) {
        try {
            tryAppend(event);
        } catch (final AppenderLoggingException ex) {
            error("Unable to write to stream " + manager.getName() + " for appender " + getName(), event, ex);
            throw ex;
        }
    }

    private void tryAppend(final LogEvent event) {
        if (Constants.ENABLE_DIRECT_ENCODERS) {
            directEncodeEvent(event);
        } else {
            writeByteArrayToManager(event);
        }
    }

    protected void directEncodeEvent(final LogEvent event) {
        getLayout().encode(event, manager);
        if (this.immediateFlush || event.isEndOfBatch()) {
            manager.flush();
        }
    }

    protected void writeByteArrayToManager(final LogEvent event) {
        final byte[] bytes = getLayout().toByteArray(event);
        if (bytes != null && bytes.length > 0) {
            manager.write(bytes, this.immediateFlush || event.isEndOfBatch());
        }
    }
}

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