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1   /*
2    * Licensed to the Apache Software Foundation (ASF) under one or more
3    * contributor license agreements. See the NOTICE file distributed with
4    * this work for additional information regarding copyright ownership.
5    * The ASF licenses this file to You under the Apache license, Version 2.0
6    * (the "License"); you may not use this file except in compliance with
7    * the License. You may obtain a copy of the License at
8    *
9    *      http://www.apache.org/licenses/LICENSE-2.0
10   *
11   * Unless required by applicable law or agreed to in writing, software
12   * distributed under the License is distributed on an "AS IS" BASIS,
13   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14   * See the license for the specific language governing permissions and
15   * limitations under the license.
16   */
17  package org.apache.logging.log4j.core.appender;
18  
19  import org.apache.logging.log4j.Logger;
20  import org.apache.logging.log4j.core.Core;
21  import org.apache.logging.log4j.core.config.AppenderRef;
22  import org.apache.logging.log4j.core.config.plugins.Plugin;
23  import org.apache.logging.log4j.core.config.plugins.PluginElement;
24  import org.apache.logging.log4j.core.config.plugins.PluginFactory;
25  import org.apache.logging.log4j.status.StatusLogger;
26  
27  /**
28   * The array of failover Appenders.
29   */
30  @Plugin(name = "failovers", category = Core.CATEGORY_NAME)
31  public final class FailoversPlugin {
32  
33      private static final Logger LOGGER = StatusLogger.getLogger();
34  
35      /**
36       * Prevent instantiation.
37       */
38      private FailoversPlugin() {
39      }
40  
41      /**
42       * Returns the appender references.
43       * @param refs The references to return.
44       * @return The appender references.
45       */
46      @PluginFactory
47      public static String[] createFailovers(@PluginElement("AppenderRef") final AppenderRef... refs) {
48  
49          if (refs == null) {
50              LOGGER.error("failovers must contain an appender reference");
51              return null;
52          }
53          final String[] arr = new String[refs.length];
54          for (int i = 0; i < refs.length; ++i) {
55              arr[i] = refs[i].getRef();
56          }
57          return arr;
58      }
59  }