Package com.tangosol.io

Class DecoratedBinaryDeltaCompressor

  • All Implemented Interfaces:
    DeltaCompressor
    public class DecoratedBinaryDeltaCompressor
extends ExternalizableHelper
implements DeltaCompressor
    A DeltaCompressor implementation that works with decorated binary values.

    The delta format is composed of a leading byte that indicates the format; the format indicator byte is one of the DECO_* field values. If the delta value does not begin with one of the leading DECO_* indicators, then the entire delta is the delta for the "value" portion of the decorated result. The grammar follows: 

     DecoratedBinaryDelta:
   DECO_DELETE_ALL OptionalValueDelta
   DecorationDeltaList DECO_TERM OptionalValueDelta
   DECO_NO_CHANGES-opt ValueDelta
   null

 OptionalValueDelta:
   VALUE_NO_CHANGES
   VALUE_CHANGES-opt ValueDelta

 ValueDelta:
   Binary (as defined by the underlying DeltaCompressor)

 DecorationDeltaList:
   DecorationDelta
   DecorationDeltaList DecorationDelta

 DecorationDelta:
   DECO_INSERT DecorationId Binary
   DECO_UPDATE DecorationId BinaryDelta
   DECO_DELETE DecorationId

 BinaryDelta:
   Binary (as returned by the BinaryDeltaCompressor)

 Binary:
   Length <bytes>

 DecorationId:
 Length:
   <packed-integer>
    Author:
    cp 2009.01.20

    • Constructor Detail

      • DecoratedBinaryDeltaCompressor

        public DecoratedBinaryDeltaCompressor​(DeltaCompressor compressorValue)
        Construct a DecoratedBinaryDeltaCompressor.
        Parameters:
        compressorValue - the compressor responsible for performing delta compression on the underlying Binary value (i.e. the DECO_VALUE decoration)

    • Method Detail

      • extractDelta

        public ReadBuffer extractDelta​(ReadBuffer bufOld,
                               ReadBuffer bufNew)
        Compare an old value to a new value and generate a delta that represents the changes that must be made to the old value in order to transform it into the new value. The generated delta must be a ReadBuffer of non-zero length.

        If the old value is null, the generated delta must be a "replace", meaning that applying it to any value must produce the specified new value.

        Specified by:
        extractDelta in interface DeltaCompressor
        Parameters:
        bufOld - the old value
        bufNew - the new value; must not be null
        Returns:
        the changes that must be made to the old value in order to transform it into the new value, or null to indicate no change