Package io.deephaven.engine.table.impl.sources

Class ReversedColumnSource<T>

java.lang.Object
io.deephaven.engine.table.impl.AbstractColumnSource<T>
io.deephaven.engine.table.impl.sources.ReversedColumnSource<T>
All Implemented Interfaces:
ChunkSource<Values>, ChunkSource.WithPrev<Values>, ColumnSource<T>, ElementSource<T>, FillContextMaker, GetContextMaker, DefaultChunkSource<Values>, DefaultChunkSource.WithPrev<Values>, Releasable, TupleExporter<T>, TupleSource<T>
public class ReversedColumnSource<T> extends AbstractColumnSource<T>
This column source wraps another column source, and returns the values in the opposite order. It must be paired with a ReverseOperation (that can be shared among reversed column sources) that implements the RowSet transformations for this source.

  • Constructor Details

    • ReversedColumnSource

      public ReversedColumnSource(@NotNull @NotNull ColumnSource<T> innerSource, @NotNull @NotNull ReverseOperation indexReverser)

  • Method Details

    • getComponentType

      public Class<?> getComponentType()
      Specified by:
      getComponentType in interface ColumnSource<T>
      Overrides:
      getComponentType in class AbstractColumnSource<T>

    • startTrackingPrevValues

      public void startTrackingPrevValues()
      Description copied from interface: ColumnSource
      ColumnSource implementations that track previous values have the option to not actually start tracking previous values until this method is called. This is an option, not an obligation: some simple ColumnSource implementations (like TSingleValueSource for various T) always track previous values; other implementations (like PrevColumnSource) never do; some (like TArrayColumnSource) only start tracking once this method is called. An immutable column source can not have distinct prev values; therefore it is implemented as a no-op.

    • get

      public T get(long rowKey)
      Description copied from interface: ElementSource
      Get the value from the source. This may return boxed values for basic types. RowKeys that are not present are undefined.
      Parameters:
      rowKey - the location in key space to get the value from.
      Returns:
      the value at the rowKey, potentially null.

    • getBoolean

      public Boolean getBoolean(long rowKey)
      Description copied from interface: ElementSource
      Get the value at the rowKey as a Boolean. RowKeys that are not present are undefined.
      Parameters:
      rowKey - the location in key space to get the value from.
      Returns:
      the boolean at the rowKey, potentially null.

    • getByte

      public byte getByte(long rowKey)
      Description copied from interface: ElementSource
      Get the value at the rowKey as a byte. RowKeys that are not present are undefined.
      Parameters:
      rowKey - the location in key space to get the value from.
      Returns:
      the boolean at the rowKey, null values are represented by QueryConstants.NULL_BYTE

    • getChar

      public char getChar(long rowKey)
      Description copied from interface: ElementSource
      Get the value at the rowKey as a char. RowKeys that are not present are undefined.
      Parameters:
      rowKey - the location in key space to get the value from.
      Returns:
      the char at the rowKey, null values are represented by QueryConstants.NULL_CHAR

    • getDouble

      public double getDouble(long rowKey)
      Description copied from interface: ElementSource
      Get the value at the rowKey as a double. RowKeys that are not present are undefined.
      Parameters:
      rowKey - the location in key space to get the value from.
      Returns:
      the double at the rowKey, null values are represented by QueryConstants.NULL_DOUBLE

    • getFloat

      public float getFloat(long rowKey)
      Description copied from interface: ElementSource
      Get the value at the rowKey as a float. RowKeys that are not present are undefined.
      Parameters:
      rowKey - the location in key space to get the value from.
      Returns:
      the float at the rowKey, null values are represented by QueryConstants.NULL_FLOAT

    • getInt

      public int getInt(long rowKey)
      Description copied from interface: ElementSource
      Get the value at the rowKey as an int. RowKeys that are not present are undefined.
      Parameters:
      rowKey - the location in key space to get the value from.
      Returns:
      the int at the rowKey, null values are represented by QueryConstants.NULL_INT

    • getLong

      public long getLong(long rowKey)
      Description copied from interface: ElementSource
      Get the value at the rowKey as a long. RowKeys that are not present are undefined.
      Parameters:
      rowKey - the location in key space to get the value from.
      Returns:
      the long at the rowKey, null values are represented by QueryConstants.NULL_LONG

    • getShort

      public short getShort(long rowKey)
      Description copied from interface: ElementSource
      Get the value at the rowKey as a short. RowKeys that are not present are undefined.
      Parameters:
      rowKey - the location in key space to get the value from.
      Returns:
      the short at the rowKey, null values are represented by QueryConstants.NULL_SHORT

    • getPrev

      public T getPrev(long rowKey)
      Description copied from interface: ElementSource
      Get the previous value at the rowKey. Previous values are used during an UG update cycle to process changes in data. During normal operation previous values will be identical to current values. RowKeys that were not present are undefined.
      Parameters:
      rowKey - the location in key space to get the value from.
      Returns:
      the previous value at the rowKey, potentially null.

    • getPrevBoolean

      public Boolean getPrevBoolean(long rowKey)
      Description copied from interface: ElementSource
      Get the previous value at the rowKey as a Boolean. See ElementSource.getPrev(long) for more details. RowKeys that were not present are undefined.
      Parameters:
      rowKey - the location in key space to get the previous value from.
      Returns:
      the previous boolean at the rowKey, potentially null.

    • getPrevByte

      public byte getPrevByte(long rowKey)
      Description copied from interface: ElementSource
      Get the previous value at the rowKey as a byte. See ElementSource.getPrev(long) for more details. RowKeys that were not present are undefined.
      Parameters:
      rowKey - the location in key space to get the previous value from.
      Returns:
      the previous boolean at the rowKey, null values are represented by QueryConstants.NULL_BYTE

    • getPrevChar

      public char getPrevChar(long rowKey)
      Description copied from interface: ElementSource
      Get the previous value at the rowKey as a char. See ElementSource.getPrev(long) for more details. RowKeys that were not present are undefined.
      Parameters:
      rowKey - ohe location in key space to get the previous value from.
      Returns:
      the previous char at the rowKey, null values are represented by QueryConstants.NULL_CHAR

    • getPrevDouble

      public double getPrevDouble(long rowKey)
      Description copied from interface: ElementSource
      Get the previous value at the rowKey as a double. See ElementSource.getPrev(long) for more details. RowKeys that were not present are undefined.
      Parameters:
      rowKey - the location in key space to get the previous value from.
      Returns:
      the previous double at the rowKey, null values are represented by QueryConstants.NULL_DOUBLE

    • getPrevFloat

      public float getPrevFloat(long rowKey)
      Description copied from interface: ElementSource
      Get the previous value at the rowKey as a float. See ElementSource.getPrev(long) for more details. RowKeys that were not present are undefined.
      Parameters:
      rowKey - the location in key space to get the previous value from.
      Returns:
      the previous float at the rowKey, null values are represented by QueryConstants.NULL_FLOAT

    • getPrevInt

      public int getPrevInt(long rowKey)
      Description copied from interface: ElementSource
      Get the previous value at the rowKey as an int. See ElementSource.getPrev(long) for more details. RowKeys that were not present are undefined.
      Parameters:
      rowKey - the location in key space to get the previous value from.
      Returns:
      the previous int at the rowKey, null values are represented by QueryConstants.NULL_INT

    • getPrevLong

      public long getPrevLong(long rowKey)
      Description copied from interface: ElementSource
      Get the previous value at the rowKey as a long. See ElementSource.getPrev(long) for more details.
      Parameters:
      rowKey - the location in key space to get the previous value from.
      Returns:
      the previous long at the rowKey, null values are represented by QueryConstants.NULL_LONG

    • getPrevShort

      public short getPrevShort(long rowKey)
      Description copied from interface: ElementSource
      Get the previous value at the rowKey as a short. See ElementSource.getPrev(long) for more details. RowKeys that were not present are undefined.
      Parameters:
      rowKey - the location in key space to get the previous value from.
      Returns:
      the previous short at the rowKey, null values are represented by QueryConstants.NULL_SHORT

    • isImmutable

      public boolean isImmutable()
      Description copied from interface: ColumnSource
      Determine if this column source is immutable, meaning that the values at a given row key never change.
      Returns:
      true if the values at a given row key of the column source never change, false otherwise

    • makeFillContext

      public ReversedColumnSource<T>.io.deephaven.engine.table.impl.sources.ReversedColumnSource.FillContext makeFillContext(int chunkCapacity, SharedContext sharedContext)
      Description copied from interface: FillContextMaker
      Allocate a new ChunkSource.FillContext for filling chunks from this FillContextMaker, typically a ChunkSource.
      Parameters:
      chunkCapacity - The maximum size of any WritableChunk that will be filled with this context
      sharedContext - Shared store of intermediate results.
      Returns:
      A context for use with fill operations

    • fillChunk

      public void fillChunk(@NotNull ChunkSource.FillContext _context, @NotNull @NotNull WritableChunk<? super Values> destination, @NotNull @NotNull RowSequence rowSequence)
      Description copied from interface: ChunkSource
      Populates the given destination chunk with data corresponding to the keys from the given RowSequence.
      Specified by:
      fillChunk in interface ChunkSource<T>
      Overrides:
      fillChunk in class AbstractColumnSource<T>
      Parameters:
      _context - A context containing all mutable/state related data used in retrieving the Chunk.
      destination - The chunk to be populated according to rowSequence. No assumptions shall be made about the size of the chunk shall be made. The chunk will be populated from position [0,rowSequence.size()).
      rowSequence - An RowSequence representing the keys to be fetched

    • fillPrevChunk

      public void fillPrevChunk(@NotNull ChunkSource.FillContext _context, @NotNull @NotNull WritableChunk<? super Values> destination, @NotNull @NotNull RowSequence rowSequence)
      Description copied from interface: ChunkSource.WithPrev
      Populates the given destination chunk with data corresponding to the keys from the given RowSequence.
      Specified by:
      fillPrevChunk in interface ChunkSource.WithPrev<T>
      Overrides:
      fillPrevChunk in class AbstractColumnSource<T>
      Parameters:
      _context - A context containing all mutable/state related data used in retrieving the Chunk.
      destination - The chunk to be populated according to rowSequence. No assumptions shall be made about the size of the chunk shall be made. The chunk will be populated from position [0,rowSequence.size()).
      rowSequence - An RowSequence representing the keys to be fetched

    • isStateless

      public boolean isStateless()
      Description copied from interface: ColumnSource
      Most column sources will return the same value for a given row without respect to the order that the rows are read. Those columns sources are considered "stateless" and should return true. Some column sources, however may be dependent on evaluation order. For example, a formula that updates a Map must be evaluated from the first row to the last row. A column source that has the potential to depend on the order of evaluation must return false.
      Returns:
      true if this is a stateless column source