content: /*
   * The Alluxio Open Foundation licenses this work under the Apache License, version 2.0
   * (the "License"). You may not use this work except in compliance with the License, which is
   * available at www.apache.org/licenses/LICENSE-2.0
   *
   * This software is distributed on an "AS IS" basis, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND,
   * either express or implied, as more fully set forth in the License.
   *
   * See the NOTICE file distributed with this work for information regarding copyright ownership.
   */
  
  package alluxio.hadoop;
  
  import alluxio.conf.AlluxioConfiguration;
  import alluxio.conf.PropertyKey;
  
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  import java.util.HashMap;
  import java.util.Map;
  import javax.annotation.concurrent.ThreadSafe;
  
  /**
   * Utility class for merging {@link AlluxioConfiguration} with Hadoop's Configuration class.
   */
  @ThreadSafe
  public final class HadoopConfigurationUtils {
    private static final Logger LOG = LoggerFactory.getLogger(HadoopConfigurationUtils.class);
  
    private HadoopConfigurationUtils() {} // Prevent instantiation.
  
    /**
     * Extracts relevant configuration from Hadoop {@link org.apache.hadoop.conf.Configuration}.
     *
     * @param hadoopConf the {@link org.apache.hadoop.conf.Configuration} to extract
     * @return all relevant properties in a Map instance
     */
    public static Map<String, Object> getConfigurationFromHadoop(
        org.apache.hadoop.conf.Configuration hadoopConf) {
      Map<String, Object> alluxioConfProperties = new HashMap<>();
      // Load any Alluxio configuration parameters in the Hadoop configuration.
      for (Map.Entry<String, String> entry : hadoopConf) {
        String propertyName = entry.getKey();
        if (PropertyKey.isValid(propertyName)) {
          alluxioConfProperties.put(propertyName, entry.getValue());
        }
      }
      return alluxioConfProperties;
    }
  
    /**
     * Merges an {@link AlluxioConfiguration} into an hadoop
     * {@link org.apache.hadoop.conf.Configuration}.
     *
     * @param source The source hadoop configuration
     * @param alluxioConf the alluxio configuration to merge
     * @return a hadoop configuration object with the properties from the {@link AlluxioConfiguration}
     */
    public static org.apache.hadoop.conf.Configuration mergeAlluxioConfiguration(
        org.apache.hadoop.conf.Configuration source, AlluxioConfiguration alluxioConf) {
      org.apache.hadoop.conf.Configuration mergedConf = new org.apache.hadoop.conf.Configuration();
      source.forEach((Map.Entry<String, String> e) -> mergedConf.set(e.getKey(), e.getValue()));
      alluxioConf.copyProperties().forEach((PropertyKey pk, Object val) -> {
        if (val != null) {
          mergedConf.set(pk.getName(), String.valueOf(val));
        }
      });
      return mergedConf;
    }
  }
  