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     */
017    package org.apache.logging.log4j.core.appender;
018    
019    import org.apache.logging.log4j.Logger;
020    import org.apache.logging.log4j.core.config.AppenderRef;
021    import org.apache.logging.log4j.core.config.plugins.Plugin;
022    import org.apache.logging.log4j.core.config.plugins.PluginElement;
023    import org.apache.logging.log4j.core.config.plugins.PluginFactory;
024    import org.apache.logging.log4j.status.StatusLogger;
025    
026    /**
027     * The array of failover Appenders.
028     */
029    @Plugin(name = "failovers", category = "Core")
030    public 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    }