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.cli.hms;
  
  import alluxio.cli.ValidationTaskResult;
  import alluxio.cli.ValidationUtils;
  import alluxio.collections.Pair;
  import alluxio.util.ExceptionUtils;
  
  import org.apache.hadoop.hive.metastore.IMetaStoreClient;
  import org.apache.hadoop.hive.metastore.api.Database;
  import org.apache.hadoop.hive.metastore.api.NoSuchObjectException;
  
  /**
   * A task which, given a metastore client can retrieve information from a user-specified
   * database.
   */
  public class DatabaseValidationTask extends MetastoreValidationTask<IMetaStoreClient, String> {
  
    private final String mDbName;
  
    /**
     * Create a new instance of {@link DatabaseValidationTask}.
     *
     * @param dbName the database name to get information from
     * @param prereq a pre-requisite task that provides a metastore client
     */
    public DatabaseValidationTask(String dbName,
        MetastoreValidationTask<?, IMetaStoreClient> prereq) {
      super(prereq);
      mDbName = dbName;
    }
  
    @Override
    Pair<ValidationTaskResult, String> getValidationWithResult() throws InterruptedException {
      if (mInputTask == null) {
        return new Pair<>(new ValidationTaskResult(ValidationUtils.State.FAILED, getName(),
            "Did not have a pre-requisite task to obtain HMS client for database check", ""), null);
      }
      Pair<ValidationTaskResult, IMetaStoreClient> res = mInputTask.getValidationWithResult();
      if (res.getFirst().getState() != ValidationUtils.State.OK) {
        return new Pair<>(res.getFirst(), null);
      }
      IMetaStoreClient client = res.getSecond();
      try {
        Database database = client.getDatabase(mDbName);
        return new Pair<>(new ValidationTaskResult(ValidationUtils.State.OK, getName(),
            String.format("Database (name: %s, description: %s)",
                database.getName(), database.getDescription()), ""), mDbName);
      } catch (NoSuchObjectException e) {
        return new Pair<>(
            new ValidationTaskResult(ValidationUtils.State.FAILED, getName(),
                ExceptionUtils.asPlainText(e),
                "Please make sure the given database name is valid "
                    + "and existing in the target hive metastore"), null);
      } catch (Throwable t) {
        return new Pair<>(new ValidationTaskResult(ValidationUtils.State.FAILED, getName(),
            ExceptionUtils.asPlainText(t), "Failed to get database from remote hive metastore"),
            null);
      } finally {
        client.close();
      }
    }
  
    @Override
    public String getName() {
      return "getDatabaseCheck";
    }
  }
  