code: /*
   * 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.skywalking.oap.server.core.logging.log4j;
  
  import org.apache.logging.log4j.core.LoggerContext;
  import org.apache.logging.log4j.core.config.Configuration;
  import org.apache.logging.log4j.core.config.ConfigurationFactory;
  import org.apache.logging.log4j.core.config.ConfigurationSource;
  import org.apache.logging.log4j.core.config.Order;
  import org.apache.logging.log4j.core.config.plugins.Plugin;
  
  /**
   * OapConfigurationFactory guarantee the log4j configuration object is {@link OapConfiguration}.
   * It guarantees the downcast {@link Configuration} to {@link OapConfiguration} safely.
   */
  @Plugin(name = "OapConfigurationFactory", category = "ConfigurationFactory")
  @Order(10)
  public class OapConfigurationFactory extends ConfigurationFactory {
      /**
       * Valid file extensions for XML files.
       */
      public static final String[] SUFFIXES = new String[] {".xml", "*"};
  
      /**
       * Returns the file suffixes for XML files.
       * @return An array of File extensions.
       */
      @Override
      public String[] getSupportedTypes() {
          return SUFFIXES;
      }
  
      /**
       * Return the configuration.
       * @param loggerContext The logger context
       * @param source The input source
       * @return the configuration
       */
      @Override
      public Configuration getConfiguration(final LoggerContext loggerContext, final ConfigurationSource source) {
          return new OapConfiguration(loggerContext, source);
      }
  }
  