public abstract class BlobDataCell extends DataCell
Cell implementations extending from this class will be separately written when a table is buffered on disc (each cell into a separate file). This has two advantages:
StringCell, which get copied when buffered multiple times.)
DataRow.getCell(int)method is invoked. (Usually, cells get deserialized when the
RowIterator.next()method is called. This may save much time when the cell is not used as for instance in a row filter, row sampler or sorter node.
SoftReference, allowing for garbage collection when memory gets limited (unless cell is otherwise referenced).
In comparison to ordinary cell implementation, objects of this class take slightly longer to (de)serialize as they get written to a separate blobs directory.
Implementation note: The content of a
usually written to a file
file in the temp directory.
BlobDataCell objects are treated
differently, they are written to a separate directory called
knime_container_date, each blob cell into a separate
|Modifier and Type||Class and Description|
Utility class that holds information where the blob is located.
|Modifier and Type||Field and Description|
Shall blob cells be compressed when saved to blob file.
|Constructor and Description|
|Modifier and Type||Method and Description|
Get the location of the blob or
Set Blob address (which can't be
equalContent, equals, equalsDataCell, getType, hashCode, isMissing, toString
public static final boolean USE_COMPRESSION
true, which means the file is compressed using the gzip compression format.
This field is accessed on the concrete implementation of
BlobDataCell using reflection. If objects of the derived
class shall not be compressed, define a static field with the same
name/type/scope, which returns
nullif it hasn't been stored just yet.
void setBlobAddress(BlobDataCell.BlobAddress blobAddress)
blobAddress- The blob address object.
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