content: /*
   * 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.asterix.external.api;
  
  import java.io.Closeable;
  import java.io.IOException;
  import java.util.function.LongSupplier;
  import java.util.function.Supplier;
  
  import org.apache.asterix.active.message.ActiveManagerMessage;
  import org.apache.asterix.external.dataflow.AbstractFeedDataFlowController;
  import org.apache.asterix.external.util.ExternalDataConstants;
  import org.apache.asterix.external.util.IFeedLogManager;
  import org.apache.hyracks.api.exceptions.HyracksDataException;
  
  /**
   * This interface represents a record reader that reads data from external source as a set of records
   *
   * @param <T>
   */
  public interface IRecordReader<T> extends Closeable {
  
      /**
       * @return true if the reader has more records remaining, false, otherwise.
       * @throws Exception if an error takes place
       */
      public boolean hasNext() throws Exception;
  
      /**
       * @return the object representing the next record.
       * @throws IOException
       * @throws InterruptedException
       */
      public IRawRecord<T> next() throws IOException, InterruptedException;
  
      /**
       * used to stop reader from producing more records.
       *
       * @return true if the connection to the external source has been suspended, false otherwise.
       */
      public boolean stop();
  
      // TODO: Find a better way to do flushes, this doesn't fit here
  
      /**
       * set a pointer to the controller of the feed. the controller can be used to flush()
       * parsed records when waiting for more records to be pushed
       */
      public void setController(AbstractFeedDataFlowController controller);
  
      // TODO: Find a better way to perform logging. this doesn't fit here
  
      /**
       * set a pointer to the log manager of the feed. the log manager can be used to log
       * progress and errors
       *
       * @throws HyracksDataException
       */
      public void setFeedLogManager(IFeedLogManager feedLogManager) throws HyracksDataException;
  
      /**
       * gives the record reader a chance to recover from IO errors during feed intake
       */
      public boolean handleException(Throwable th);
  
      public default IFeedMarker getProgressReporter() {
          return null;
      }
  
      /**
       * @return JSON String containing ingestion stats
       */
      default String getStats() {
          return null;
      }
  
      default Supplier<String> getDataSourceName() {
          return ExternalDataConstants.EMPTY_STRING;
      }
  
      default LongSupplier getLineNumber() {
          return ExternalDataConstants.NO_LINES;
      }
  
      default void handleGenericEvent(ActiveManagerMessage event) {
          throw new IllegalStateException("unexpected generic event " + event);
      }
  }
  