Package org.apache.cassandra.db.transform

Class Transformation<I extends BaseRowIterator<?>>

java.lang.Object
org.apache.cassandra.db.transform.Transformation<I>
Direct Known Subclasses:
DuplicateRowChecker, EmptyPartitionsDiscarder, EnsureOnHeap, Filter, PurgeFunction, RTBoundCloser, RTBoundValidator, ShortReadPartitionsProtection, StoppingTransformation, TopPartitionTracker.TombstoneCounter, WithOnlyQueriedData
public abstract class Transformation<I extends BaseRowIterator<?>> extends Object
We have a single common superclass for all Transformations to make implementation efficient. we have a shared stack for all transformations, and can share the same transformation across partition and row iterators, reducing garbage. Internal code is also simplified by always having a basic no-op implementation to invoke. Only the necessary methods need be overridden. Early termination is provided by invoking the method's stop or stopInPartition methods, rather than having their own abstract method to invoke, as this is both more efficient and simpler to reason about.

  • Constructor Details

    • Transformation

      public Transformation()

  • Method Details

    • onClose

      protected void onClose()
      Run on the close of any (logical) partitions iterator this function was applied to We stipulate logical, because if applied to a transformed iterator the lifetime of the iterator object may be longer than the lifetime of the "logical" iterator it was applied to; if the iterator is refilled with MoreContents, for instance, the iterator may outlive this function

    • onPartitionClose

      protected void onPartitionClose()
      Run on the close of any (logical) rows iterator this function was applied to We stipulate logical, because if applied to a transformed iterator the lifetime of the iterator object may be longer than the lifetime of the "logical" iterator it was applied to; if the iterator is refilled with MoreContents, for instance, the iterator may outlive this function

    • applyToPartition

      protected I applyToPartition(I partition)
      Applied to any rows iterator (partition) we encounter in a partitions iterator

    • applyToRow

      protected Row applyToRow(Row row)
      Applied to any row we encounter in a rows iterator

    • applyToMarker

      protected RangeTombstoneMarker applyToMarker(RangeTombstoneMarker marker)
      Applied to any RTM we encounter in a rows/unfiltered iterator

    • applyToPartitionKey

      protected DecoratedKey applyToPartitionKey(DecoratedKey key)
      Applied to the partition key of any rows/unfiltered iterator we are applied to

    • applyToStatic

      protected Row applyToStatic(Row row)
      Applied to the static row of any rows iterator. NOTE that this is only applied to the first iterator in any sequence of iterators filled by a MoreContents; the static data for such iterators is all expected to be equal

    • applyToDeletion

      protected DeletionTime applyToDeletion(DeletionTime deletionTime)
      Applied to the partition-level deletion of any rows iterator. NOTE that this is only applied to the first iterator in any sequence of iterators filled by a MoreContents; the static data for such iterators is all expected to be equal

    • applyToPartitionColumns

      protected RegularAndStaticColumns applyToPartitionColumns(RegularAndStaticColumns columns)
      Applied to the PartitionColumns of any rows iterator. NOTE: same remark than for applyToDeletion: it is only applied to the first iterator in a sequence of iterators filled by MoreContents.

    • apply

      public static UnfilteredPartitionIterator apply(UnfilteredPartitionIterator iterator, Transformation<? super UnfilteredRowIterator> transformation)

    • apply

      public static PartitionIterator apply(PartitionIterator iterator, Transformation<? super RowIterator> transformation)

    • apply

      public static UnfilteredRowIterator apply(UnfilteredRowIterator iterator, Transformation<?> transformation)

    • apply

      public static RowIterator apply(RowIterator iterator, Transformation<?> transformation)