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/RollingFileAppender.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.HashMap;
import java.util.Map;
import java.util.concurrent.TimeUnit;
import java.util.zip.Deflater;

import org.apache.logging.log4j.core.Appender;
import org.apache.logging.log4j.core.Core;
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.appender.rolling.DefaultRolloverStrategy;
import org.apache.logging.log4j.core.appender.rolling.DirectFileRolloverStrategy;
import org.apache.logging.log4j.core.appender.rolling.DirectWriteRolloverStrategy;
import org.apache.logging.log4j.core.appender.rolling.RollingFileManager;
import org.apache.logging.log4j.core.appender.rolling.RolloverStrategy;
import org.apache.logging.log4j.core.appender.rolling.TriggeringPolicy;
import org.apache.logging.log4j.core.config.Configuration;
import org.apache.logging.log4j.core.config.Property;
import org.apache.logging.log4j.core.config.plugins.Plugin;
import org.apache.logging.log4j.core.config.plugins.PluginBuilderAttribute;
import org.apache.logging.log4j.core.config.plugins.PluginBuilderFactory;
import org.apache.logging.log4j.core.config.plugins.PluginElement;
import org.apache.logging.log4j.core.config.plugins.validation.constraints.Required;
import org.apache.logging.log4j.core.net.Advertiser;
import org.apache.logging.log4j.core.util.Booleans;
import org.apache.logging.log4j.core.util.Integers;

/**
 * An appender that writes to files and can roll over at intervals.
 */
@Plugin(name = RollingFileAppender.PLUGIN_NAME, category = Core.CATEGORY_NAME, elementType = Appender.ELEMENT_TYPE, printObject = true)
public final class RollingFileAppender extends AbstractOutputStreamAppender<RollingFileManager> {

    public static final String PLUGIN_NAME = "RollingFile";

    /**
     * Builds FileAppender instances.
     *
     * @param <B>
     *            The type to build
     * @since 2.7
     */
    public static class Builder<B extends Builder<B>> extends AbstractOutputStreamAppender.Builder<B>
            implements org.apache.logging.log4j.core.util.Builder<RollingFileAppender> {

        @PluginBuilderAttribute
        private String fileName;

        @PluginBuilderAttribute
        @Required
        private String filePattern;

        @PluginBuilderAttribute
        private boolean append = true;

        @PluginBuilderAttribute
        private boolean locking;

        @PluginElement("Policy")
        @Required
        private TriggeringPolicy policy;

        @PluginElement("Strategy")
        private RolloverStrategy strategy;

        @PluginBuilderAttribute
        private boolean advertise;

        @PluginBuilderAttribute
        private String advertiseUri;

        @PluginBuilderAttribute
        private boolean createOnDemand;

        @PluginBuilderAttribute
        private String filePermissions;

        @PluginBuilderAttribute
        private String fileOwner;

        @PluginBuilderAttribute
        private String fileGroup;

        @Override
        public RollingFileAppender build() {
            // Even though some variables may be annotated with @Required, we must still perform validation here for
            // call sites that build builders programmatically.
            final boolean isBufferedIo = isBufferedIo();
            final int bufferSize = getBufferSize();
            if (getName() == null) {
                LOGGER.error("RollingFileAppender '{}': No name provided.", getName());
                return null;
            }

            if (!isBufferedIo && bufferSize > 0) {
                LOGGER.warn("RollingFileAppender '{}': The bufferSize is set to {} but bufferedIO is not true", getName(), bufferSize);
            }

            if (filePattern == null) {
                LOGGER.error("RollingFileAppender '{}': No file name pattern provided.", getName());
                return null;
            }

            if (policy == null) {
                LOGGER.error("RollingFileAppender '{}': No TriggeringPolicy provided.", getName());
                return null;
            }

            if (strategy == null) {
                if (fileName != null) {
                    strategy = DefaultRolloverStrategy.newBuilder()
                                        .withCompressionLevelStr(String.valueOf(Deflater.DEFAULT_COMPRESSION))
                                        .withConfig(getConfiguration())
                                        .build();
                } else {
                    strategy = DirectWriteRolloverStrategy.newBuilder()
                                        .withCompressionLevelStr(String.valueOf(Deflater.DEFAULT_COMPRESSION))
                                        .withConfig(getConfiguration())
                                        .build();
                }
            } else if (fileName == null && !(strategy instanceof DirectFileRolloverStrategy)) {
                LOGGER.error("RollingFileAppender '{}': When no file name is provided a {} must be configured", getName(), DirectFileRolloverStrategy.class.getSimpleName());
                return null;
            }

            final Layout<? extends Serializable> layout = getOrCreateLayout();
            final RollingFileManager manager = RollingFileManager.getFileManager(fileName, filePattern, append,
                    isBufferedIo, policy, strategy, advertiseUri, layout, bufferSize, isImmediateFlush(),
                    createOnDemand, filePermissions, fileOwner, fileGroup, getConfiguration());
            if (manager == null) {
                return null;
            }

            manager.initialize();

            return new RollingFileAppender(getName(), layout, getFilter(), manager, fileName, filePattern,
                    isIgnoreExceptions(), isImmediateFlush(), advertise ? getConfiguration().getAdvertiser() : null,
                    getPropertyArray());
        }

        public String getAdvertiseUri() {
            return advertiseUri;
        }

        public String getFileName() {
            return fileName;
        }

        public boolean isAdvertise() {
            return advertise;
        }

        public boolean isAppend() {
            return append;
        }

        public boolean isCreateOnDemand() {
            return createOnDemand;
        }

        public boolean isLocking() {
            return locking;
        }

        public String getFilePermissions() {
            return filePermissions;
        }

        public String getFileOwner() {
            return fileOwner;
        }

        public String getFileGroup() {
            return fileGroup;
        }

        public B withAdvertise(final boolean advertise) {
            this.advertise = advertise;
            return asBuilder();
        }

        public B withAdvertiseUri(final String advertiseUri) {
            this.advertiseUri = advertiseUri;
            return asBuilder();
        }

        public B withAppend(final boolean append) {
            this.append = append;
            return asBuilder();
        }

        public B withFileName(final String fileName) {
            this.fileName = fileName;
            return asBuilder();
        }

        public B withCreateOnDemand(final boolean createOnDemand) {
            this.createOnDemand = createOnDemand;
            return asBuilder();
        }

        public B withLocking(final boolean locking) {
            this.locking = locking;
            return asBuilder();
        }

        public String getFilePattern() {
            return filePattern;
        }

        public TriggeringPolicy getPolicy() {
            return policy;
        }

        public RolloverStrategy getStrategy() {
            return strategy;
        }

        public B withFilePattern(final String filePattern) {
            this.filePattern = filePattern;
            return asBuilder();
        }

        public B withPolicy(final TriggeringPolicy policy) {
            this.policy = policy;
            return asBuilder();
        }

        public B withStrategy(final RolloverStrategy strategy) {
            this.strategy = strategy;
            return asBuilder();
        }

        public B withFilePermissions(final String filePermissions) {
            this.filePermissions = filePermissions;
            return asBuilder();
        }

        public B withFileOwner(final String fileOwner) {
            this.fileOwner = fileOwner;
            return asBuilder();
        }

        public B withFileGroup(final String fileGroup) {
            this.fileGroup = fileGroup;
            return asBuilder();
        }

    }

    private static final int DEFAULT_BUFFER_SIZE = 8192;

    private final String fileName;
    private final String filePattern;
    private Object advertisement;
    private final Advertiser advertiser;

    private RollingFileAppender(final String name, final Layout<? extends Serializable> layout, final Filter filter,
            final RollingFileManager manager, final String fileName, final String filePattern,
            final boolean ignoreExceptions, final boolean immediateFlush, final Advertiser advertiser,
            final Property[] properties) {
        super(name, layout, filter, ignoreExceptions, immediateFlush, properties, manager);
        if (advertiser != null) {
            final Map<String, String> configuration = new HashMap<>(layout.getContentFormat());
            configuration.put("contentType", layout.getContentType());
            configuration.put("name", name);
            advertisement = advertiser.advertise(configuration);
        }
        this.fileName = fileName;
        this.filePattern = filePattern;
        this.advertiser = advertiser;
    }

    @Override
    public boolean stop(final long timeout, final TimeUnit timeUnit) {
        setStopping();
        final boolean stopped = super.stop(timeout, timeUnit, false);
        if (advertiser != null) {
            advertiser.unadvertise(advertisement);
        }
        setStopped();
        return stopped;
    }

    /**
     * Writes the log entry rolling over the file when required.

     * @param event The LogEvent.
     */
    @Override
    public void append(final LogEvent event) {
        getManager().checkRollover(event);
        super.append(event);
    }

    /**
     * Returns the File name for the Appender.
     * @return The file name.
     */
    public String getFileName() {
        return fileName;
    }

    /**
     * Returns the file pattern used when rolling over.
     * @return The file pattern.
     */
    public String getFilePattern() {
        return filePattern;
    }

    /**
     * Returns the triggering policy.
     * @param <T> TriggeringPolicy type
     * @return The TriggeringPolicy
     */
    public <T extends TriggeringPolicy> T getTriggeringPolicy() {
        return getManager().getTriggeringPolicy();
    }

    /**
     * Creates a RollingFileAppender.
     * @param fileName The name of the file that is actively written to. (required).
     * @param filePattern The pattern of the file name to use on rollover. (required).
     * @param append If true, events are appended to the file. If false, the file
     * is overwritten when opened. Defaults to "true"
     * @param name The name of the Appender (required).
     * @param bufferedIO When true, I/O will be buffered. Defaults to "true".
     * @param bufferSizeStr buffer size for buffered IO (default is 8192).
     * @param immediateFlush When true, events are immediately flushed. Defaults to "true".
     * @param policy The triggering policy. (required).
     * @param strategy The rollover strategy. Defaults to DefaultRolloverStrategy.
     * @param layout The layout to use (defaults to the default PatternLayout).
     * @param filter The Filter or null.
     * @param ignore If {@code "true"} (default) exceptions encountered when appending events are logged; otherwise
     *               they are propagated to the caller.
     * @param advertise "true" if the appender configuration should be advertised, "false" otherwise.
     * @param advertiseUri The advertised URI which can be used to retrieve the file contents.
     * @param config The Configuration.
     * @return A RollingFileAppender.
     * @deprecated Use {@link #newBuilder()}.
     */
    @Deprecated
    public static <B extends Builder<B>> RollingFileAppender createAppender(
            // @formatter:off
            final String fileName,
            final String filePattern,
            final String append,
            final String name,
            final String bufferedIO,
            final String bufferSizeStr,
            final String immediateFlush,
            final TriggeringPolicy policy,
            final RolloverStrategy strategy,
            final Layout<? extends Serializable> layout,
            final Filter filter,
            final String ignore,
            final String advertise,
            final String advertiseUri,
            final Configuration config) {
            // @formatter:on
        final int bufferSize = Integers.parseInt(bufferSizeStr, DEFAULT_BUFFER_SIZE);
        // @formatter:off
        return RollingFileAppender.<B>newBuilder()
        .withAdvertise(Boolean.parseBoolean(advertise))
        .withAdvertiseUri(advertiseUri)
        .withAppend(Booleans.parseBoolean(append, true))
        .withBufferedIo(Booleans.parseBoolean(bufferedIO, true))
        .withBufferSize(bufferSize)
        .setConfiguration(config)
        .withFileName(fileName)
        .withFilePattern(filePattern).setFilter(filter).setIgnoreExceptions(Booleans.parseBoolean(ignore, true))
                .withImmediateFlush(Booleans.parseBoolean(immediateFlush, true)).setLayout(layout)
                .withCreateOnDemand(false)
                .withLocking(false).setName(name)
                .withPolicy(policy)
                .withStrategy(strategy)
                .build();
        // @formatter:on
    }

    /**
     * Creates a new Builder.
     *
     * @return a new Builder.
     * @since 2.7
     */
    @PluginBuilderFactory
    public static <B extends Builder<B>> B newBuilder() {
        return new Builder<B>().asBuilder();
    }
}

⏎ org/apache/logging/log4j/core/appender/RollingFileAppender.java

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File name: log4j-core-2.14.1-sources.jar
File size: 1281358 bytes
Release date: 2021-03-06
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