001/*
002 * Licensed to the Apache Software Foundation (ASF) under one or more
003 * contributor license agreements. See the NOTICE file distributed with
004 * this work for additional information regarding copyright ownership.
005 * The ASF licenses this file to You under the Apache license, Version 2.0
006 * (the "License"); you may not use this file except in compliance with
007 * the License. You may obtain a copy of the License at
008 *
009 *      http://www.apache.org/licenses/LICENSE-2.0
010 *
011 * Unless required by applicable law or agreed to in writing, software
012 * distributed under the License is distributed on an "AS IS" BASIS,
013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014 * See the license for the specific language governing permissions and
015 * limitations under the license.
016 */
017package org.apache.logging.log4j.core.appender;
018
019import org.apache.logging.log4j.Logger;
020import org.apache.logging.log4j.core.config.AppenderRef;
021import org.apache.logging.log4j.core.config.plugins.Plugin;
022import org.apache.logging.log4j.core.config.plugins.PluginElement;
023import org.apache.logging.log4j.core.config.plugins.PluginFactory;
024import org.apache.logging.log4j.status.StatusLogger;
025
026/**
027 * The array of failover Appenders.
028 */
029@Plugin(name = "failovers", category = "Core")
030public final class FailoversPlugin {
031
032    private static final Logger LOGGER = StatusLogger.getLogger();
033
034    /**
035     * Prevent instantiation.
036     */
037    private FailoversPlugin() {
038    }
039
040    /**
041     * Returns the appender references.
042     * @param refs The references to return.
043     * @return The appender references.
044     */
045    @PluginFactory
046    public static String[] createFailovers(@PluginElement("AppenderRef") final AppenderRef... refs) {
047
048        if (refs == null) {
049            LOGGER.error("failovers must contain an appender reference");
050            return null;
051        }
052        final String[] arr = new String[refs.length];
053        for (int i = 0; i < refs.length; ++i) {
054            arr[i] = refs[i].getRef();
055        }
056        return arr;
057    }
058}