Package org.apache.hadoop.mapred.join

Interface ComposableRecordReader<K extends WritableComparable,V extends Writable>

All Superinterfaces:
AutoCloseable, Closeable, Comparable<ComposableRecordReader<K,?>>, RecordReader<K,V>
All Known Implementing Classes:
InnerJoinRecordReader, JoinRecordReader, MultiFilterRecordReader, OuterJoinRecordReader, OverrideRecordReader, WrappedRecordReader
@Public @Stable public interface ComposableRecordReader<K extends WritableComparable,V extends Writable> extends RecordReader<K,V>, Comparable<ComposableRecordReader<K,?>>
Additional operations required of a RecordReader to participate in a join.

  • Method Summary

    Modifier and Type
    Method
    Description
    void
    accept(org.apache.hadoop.mapred.join.CompositeRecordReader.JoinCollector jc, K key)
    While key-value pairs from this RecordReader match the given key, register them with the JoinCollector provided.
    boolean
    hasNext()
    Returns true if the stream is not empty, but provides no guarantee that a call to next(K,V) will succeed.
    int
    id()
    Return the position in the collector this class occupies.
    K
    key()
    Return the key this RecordReader would supply on a call to next(K,V)
    void
    key(K key)
    Clone the key at the head of this RecordReader into the object provided.
    void
    skip(K key)
    Skip key-value pairs with keys less than or equal to the key provided.

    Methods inherited from interface java.lang.Comparable

    compareTo

    Methods inherited from interface org.apache.hadoop.mapred.RecordReader

    close, createKey, createValue, getPos, getProgress, next

  • Method Details

    • id

      int id()
      Return the position in the collector this class occupies.

    • key

      K key()
      Return the key this RecordReader would supply on a call to next(K,V)

    • key

      void key(K key) throws IOException
      Clone the key at the head of this RecordReader into the object provided.
      Throws:
      IOException

    • hasNext

      boolean hasNext()
      Returns true if the stream is not empty, but provides no guarantee that a call to next(K,V) will succeed.

    • skip

      void skip(K key) throws IOException
      Skip key-value pairs with keys less than or equal to the key provided.
      Throws:
      IOException

    • accept

      void accept(org.apache.hadoop.mapred.join.CompositeRecordReader.JoinCollector jc, K key) throws IOException
      While key-value pairs from this RecordReader match the given key, register them with the JoinCollector provided.
      Throws:
      IOException