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.underfs.hdfs;
  
  import alluxio.AlluxioURI;
  import alluxio.conf.AlluxioConfiguration;
  import alluxio.conf.Configuration;
  import alluxio.conf.PropertyKey;
  import alluxio.underfs.UnderFileSystem;
  import alluxio.underfs.UnderFileSystemConfiguration;
  import alluxio.underfs.UnderFileSystemFactory;
  
  import com.google.common.base.Preconditions;
  
  import javax.annotation.concurrent.ThreadSafe;
  
  /**
   * Factory for creating {@link HdfsUnderFileSystem}.
   *
   * It caches created {@link HdfsUnderFileSystem}s, using the scheme and authority pair as the key.
   */
  @ThreadSafe
  public class HdfsUnderFileSystemFactory implements UnderFileSystemFactory {
  
    /**
     * Constructs a new {@link HdfsUnderFileSystemFactory}.
     */
    public HdfsUnderFileSystemFactory() { }
  
    @Override
    public UnderFileSystem create(String path, UnderFileSystemConfiguration conf) {
      Preconditions.checkNotNull(path, "path");
      return HdfsUnderFileSystem.createInstance(new AlluxioURI(path), conf);
    }
  
    @Override
    public boolean supportsPath(String path) {
      // This loads the static configuration from the JVM's system properties and the site properties
      // file at the time of instantiation. Because of this, setting the property
      // UNDERFS_HDFS_PREFIXES programmatically *not* work.
  
      if (path != null) {
        // TODO(hy): In Hadoop 2.x this can be replaced with the simpler call to
        // FileSystem.getFileSystemClass() without any need for having users explicitly declare the
        // file system schemes to treat as being HDFS. However as long as pre 2.x versions of Hadoop
        // are supported this is not an option and we have to continue to use this method.
        for (final String prefix : Configuration.global()
            .getList(PropertyKey.UNDERFS_HDFS_PREFIXES)) {
          if (path.startsWith(prefix)) {
            return true;
          }
        }
      }
      return false;
    }
  
    @Override
    public boolean supportsPath(String path, UnderFileSystemConfiguration conf) {
      if (path != null) {
        // This loads the configuration from the JVM's system properties and the site properties file
        // on disk. Because of this, setting the property UNDERFS_HDFS_PREFIXES programmatically *not*
        // work.
        AlluxioConfiguration alluxioConf = Configuration.global();
  
        // TODO(hy): In Hadoop 2.x this can be replaced with the simpler call to
        // FileSystem.getFileSystemClass() without any need for having users explicitly declare the
        // file system schemes to treat as being HDFS. However as long as pre 2.x versions of Hadoop
        // are supported this is not an option and we have to continue to use this method.
        for (final String prefix : alluxioConf.getList(PropertyKey.UNDERFS_HDFS_PREFIXES)) {
          if (path.startsWith(prefix)) {
            if (!conf.isSetByUser(PropertyKey.UNDERFS_VERSION)
                || HdfsVersion.matches(conf.getString(PropertyKey.UNDERFS_VERSION), getVersion())) {
              return true;
            }
          }
        }
      }
      return false;
    }
  
    @Override
    public String getVersion() {
      return alluxio.UfsConstants.UFS_HADOOP_VERSION;
    }
  }
  