core/src/main/java/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 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.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.plugins.Plugin;
import org.apache.logging.log4j.core.config.plugins.PluginAttr;
import org.apache.logging.log4j.core.config.plugins.PluginConfiguration;
import org.apache.logging.log4j.core.config.plugins.PluginElement;
import org.apache.logging.log4j.core.config.plugins.PluginFactory;
import org.apache.logging.log4j.core.layout.PatternLayout;
import org.apache.logging.log4j.core.net.Advertiser;

import java.io.Serializable;
import java.util.HashMap;
import java.util.Map;

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

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


    private RollingFileAppender(final String name, final Layout<T> layout, final Filter filter,
                                final RollingFileManager manager, final String fileName,
                                final String filePattern, final boolean handleException, final boolean immediateFlush,
                                Advertiser advertiser) {
        super(name, layout, filter, handleException, immediateFlush, manager);
        if (advertiser != null)
        {
            Map<String, String> configuration = new HashMap<String, String>(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 void stop() {
        super.stop();
        if (advertiser != null) {
            advertiser.unadvertise(advertisement);
        }
    }

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

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

    /**
     * Create 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 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 suppress "true" if exceptions should be hidden from the application, "false" otherwise.
     * The default is "true".
     * @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.
     */
    @PluginFactory
    public static <S extends Serializable> RollingFileAppender<S> createAppender(
                                              @PluginAttr("fileName") final String fileName,
                                              @PluginAttr("filePattern") final String filePattern,
                                              @PluginAttr("append") final String append,
                                              @PluginAttr("name") final String name,
                                              @PluginAttr("bufferedIO") final String bufferedIO,
                                              @PluginAttr("immediateFlush") final String immediateFlush,
                                              @PluginElement("policy") final TriggeringPolicy policy,
                                              @PluginElement("strategy") RolloverStrategy strategy,
                                              @PluginElement("layout") Layout<S> layout,
                                              @PluginElement("filter") final Filter filter,
                                              @PluginAttr("suppressExceptions") final String suppress,
                                              @PluginAttr("advertise") final String advertise,
                                              @PluginAttr("advertiseURI") final String advertiseURI,
                                              @PluginConfiguration final Configuration config) {

        final boolean isAppend = append == null ? true : Boolean.valueOf(append);
        final boolean handleExceptions = suppress == null ? true : Boolean.valueOf(suppress);
        final boolean isBuffered = bufferedIO == null ? true : Boolean.valueOf(bufferedIO);
        final boolean isFlush = immediateFlush == null ? true : Boolean.valueOf(immediateFlush);
        boolean isAdvertise = advertise == null ? false : Boolean.valueOf(advertise);
        if (name == null) {
            LOGGER.error("No name provided for FileAppender");
            return null;
        }

        if (fileName == null) {
            LOGGER.error("No filename was provided for FileAppender with name "  + name);
            return null;
        }

        if (filePattern == null) {
            LOGGER.error("No filename pattern provided for FileAppender with name "  + name);
            return null;
        }

        if (policy == null) {
            LOGGER.error("A TriggeringPolicy must be provided");
            return null;
        }

        if (strategy == null) {
            strategy = DefaultRolloverStrategy.createStrategy(null, null, "true", config);
        }

        if (layout == null) {
            @SuppressWarnings({"unchecked", "UnnecessaryLocalVariable"})
            Layout<S> l = (Layout<S>)PatternLayout.createLayout(null, null, null, null, null);
            layout = l;
        }

        final RollingFileManager manager = RollingFileManager.getFileManager(fileName, filePattern, isAppend,
            isBuffered, policy, strategy, advertiseURI, layout);
        if (manager == null) {
            return null;
        }

        return new RollingFileAppender<S>(name, layout, filter, manager, fileName, filePattern,
            handleExceptions, isFlush, isAdvertise ? config.getAdvertiser() : null);
    }
}