Package org.apache.druid.frame.write.columnar

Interface FrameColumnWriter

All Superinterfaces:
AutoCloseable, Closeable
All Known Implementing Classes:
ComplexFrameColumnWriter, DoubleArrayFrameColumnWriter, DoubleFrameColumnWriter, FloatArrayFrameColumnWriter, FloatFrameColumnWriter, LongArrayFrameColumnWriter, LongFrameColumnWriter, NumericArrayFrameColumnWriter, StringFrameColumnWriter
public interface FrameColumnWriter extends Closeable
Represent writers for the columnar frames. The class objects must be provided with information on what values to write, usually provided as a ColumnValueSelector and where to write to, usually temporary growable memory addSelection() will be called repeatedly, as the current value to write gets updated. For the final write, call writeTo(org.apache.datasketches.memory.WritableMemory, long), which will copy the values we have added so far to the destination memory.

  • Method Summary

    Modifier and Type
    Method
    Description
    boolean
    addSelection()
    Adds the current value to the writer
    void
    close()
     
    long
    size()
    Size (in bytes) of the column data that will get written when writeTo(org.apache.datasketches.memory.WritableMemory, long) will be called
    void
    undo()
    Reverts the last added value.
    long
    writeTo(org.apache.datasketches.memory.WritableMemory memory, long position)
    Writes the value of the column to the provided memory at the given position

  • Method Details

    • addSelection

      boolean addSelection()
      Adds the current value to the writer

    • undo

      void undo()
      Reverts the last added value. Undo calls cannot be called in successsion

    • size

      long size()
      Size (in bytes) of the column data that will get written when writeTo(org.apache.datasketches.memory.WritableMemory, long) will be called

    • writeTo

      long writeTo(org.apache.datasketches.memory.WritableMemory memory, long position)
      Writes the value of the column to the provided memory at the given position

    • close

      void close()
      Specified by:
      close in interface AutoCloseable
      Specified by:
      close in interface Closeable