/*
 * 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.gobblin.data.management.version.finder;

import java.io.IOException;
import java.util.Collection;

import org.apache.gobblin.dataset.Dataset;
import org.apache.gobblin.data.management.version.DatasetVersion;

import org.apache.hadoop.fs.RemoteIterator;


/**
 * Finds dataset versions.
 *
 * @param <T> Type of {@link DatasetVersion} expected from this class.
 */
public interface VersionFinder<T extends DatasetVersion> {

  /**
   * Should return class of T.
   */
  public abstract Class<? extends DatasetVersion> versionClass();

  /**
   * Find dataset versions for {@link Dataset}. Each dataset versions represents a single manageable unit in the dataset.
   *
   * @param dataset which contains all versions.
   * @return Collection of {@link DatasetVersion} for each dataset version found.
   * @throws IOException
   */
  public Collection<T> findDatasetVersions(Dataset dataset)
      throws IOException;

  /**
   * Find dataset versions for {@link Dataset}. Each dataset versions represents a single manageable unit in the dataset.
   *
   * @param dataset
   * @return - an iterator
   * @throws IOException
   */
  public default RemoteIterator<T> findDatasetVersion(Dataset dataset)
      throws IOException {
    return (RemoteIterator<T>) findDatasetVersions(dataset).stream().iterator();
  }

  /**
   * Returns a boolean to identify whether to use iteratorVersion or Collections
   * for finding dataset versions
   *
   * @return
   */
  public default boolean useIteratorForFindingVersions() {
    return false;
  }
}
