package net.sf.flatpack;
   
   import java.util.Iterator;
   import java.util.NoSuchElementException;
   import java.util.Optional;
   import java.util.Spliterator;
   import java.util.Spliterators;
   import java.util.stream.Stream;
   import java.util.stream.StreamSupport;
  
  /**
   * New with jdk8, define stream() methods. You should
   * start using this BUT note that it will only return VALID Records, any invalid row will be skipped.
   *
   * @author Benoit Xhenseval
   * @since 3.4
   */
  public interface StreamingDataSet extends RecordDataSet {
      /**
       * @since 4.0
       * @return a stream of Records
       */
      default Stream<Record> stream() {
          return StreamSupport
                  .stream(Spliterators.spliteratorUnknownSize(spliterator(), Spliterator.ORDERED | Spliterator.NONNULL | Spliterator.IMMUTABLE), false);
      }
  
      /**
       * @since 4.0
       * @return a stream of Records
       */
      default Stream<Record> parallelStream() {
          return StreamSupport
                  .stream(Spliterators.spliteratorUnknownSize(spliterator(), Spliterator.ORDERED | Spliterator.NONNULL | Spliterator.IMMUTABLE), true);
      }
  
      default Iterator<Record> spliterator() {
          return new Iterator<Record>() {
              Optional<Record> nextData = Optional.empty();
  
              @Override
              public boolean hasNext() {
                  if (nextData.isPresent()) {
                      return true;
                  } else {
                      if (StreamingDataSet.this.next()) {
                          nextData = getRecord();
                      } else {
                          nextData = Optional.empty();
                      }
                      return nextData.isPresent();
                  }
              }
  
              @Override
              public Record next() {
                  if (nextData.isPresent() || hasNext()) {
                      final Record line = nextData.isPresent() ? nextData.get() : null;
                      nextData = Optional.empty();
                      return line;
                  } else {
                      throw new NoSuchElementException();
                  }
              }
          };
      }
  }