org.knime.core.data.container
Class DCObjectOutputVersion2

java.lang.Object
  org.knime.core.data.container.DCObjectOutputVersion2

All Implemented Interfaces:

KNIMEStreamConstants

 class DCObjectOutputVersion2
extends Object
implements KNIMEStreamConstants

Object writing the binary stream of a Buffer.

This class provides functionality to write DataCell objects in both possibles modes: Using a custom DataCellSerializer (for DataCell class that offer it) as well as plain (and slow) java serialization.

The general stream layout is as follows: Objects of this class write to a BlockableOutputStream in order to write DataCells to an isolated sandbox. Each DataCell entry is preceded by one or more control bytes, which are written by the associated Buffer. The Buffer also decides when to close a block. DataCell which need to be java serialized are written a freshly created ObjectOutputStream (for each cell a new stream).

Author:

Bernd Wiswedel, University of Konstanz

Field Summary

Fields inherited from interface org.knime.core.data.container.KNIMEStreamConstants

BYTE_ROW_SEPARATOR, BYTE_TYPE_MISSING, BYTE_TYPE_SERIALIZATION, BYTE_TYPE_START, DUMMY_ROW_KEY, TC_ESCAPE, TC_TERMINATE

Constructor Summary

DCObjectOutputVersion2(OutputStream out, Buffer ownerBuffer)
Setups a new output stream.

Method Summary

void	close() Closes the underlying streams.
(package private) void	endBlock() Marks the end of the block.
(package private) void	endRow() Writes the row end identifier.
void	flush() Flushes the underlying streams.
(package private) void	writeBlobAddress(BlobDataCell.BlobAddress address) Writes a given blob address to the stream.
(package private) void	writeControlByte(int controlByte) Writes the argument byte.
(package private) void	writeDataCellPerJavaSerialization(DataCell cell) Writes a cell using java serialization.
(package private) void	writeDataCellPerKNIMESerializer(DataCellSerializer<DataCell> serializer, DataCell cell) Writes a data cell using the serializer.
(package private) void	writeRowKey(RowKey key) Writes a row key by writing the underlying string to the stream.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

DCObjectOutputVersion2

public DCObjectOutputVersion2(OutputStream out,
                              Buffer ownerBuffer)

Setups a new output stream.

Parameters:

out - The stream to write to (the file)

ownerBuffer - the associated buffer.

Method Detail

writeDataCellPerKNIMESerializer

void writeDataCellPerKNIMESerializer(DataCellSerializer<DataCell> serializer,
                                     DataCell cell)
                               throws IOException

Writes a data cell using the serializer. No blocking is done (not here).

Parameters:

serializer - The factory being used to write the cell.

cell - The cell to be written.

Throws:

IOException - If that fails.

See Also:

DataCellSerializer.serialize(DataCell, DataCellDataOutput)

writeDataCellPerJavaSerialization

void writeDataCellPerJavaSerialization(DataCell cell)
                                 throws IOException

Writes a cell using java serialization. This method will create a new ObjectOutputStream for this single cell.

Parameters:

cell - The cell to write.

Throws:

IOException - If any exception occur.

writeBlobAddress

void writeBlobAddress(BlobDataCell.BlobAddress address)
                throws IOException

Writes a given blob address to the stream.

Parameters:

address - to write out.

Throws:

IOException - if that fails

writeRowKey

void writeRowKey(RowKey key)
           throws IOException

Writes a row key by writing the underlying string to the stream.

Parameters:

key - Key to write

Throws:

IOException - In case of stream corruption.

writeControlByte

void writeControlByte(int controlByte)
                throws IOException

Writes the argument byte.

Parameters:

controlByte - The byte to write.

Throws:

IOException - In case of stream corruption.

endBlock

void endBlock()
        throws IOException

Marks the end of the block.

Throws:

IOException - In case of stream corruption.

endRow

void endRow()
      throws IOException

Writes the row end identifier.

Throws:

IOException - In case of stream corruption.

close

public void close()
           throws IOException

Closes the underlying streams.

Throws:

IOException - If the stream closing causes IO problems.

flush

public void flush()
           throws IOException

Flushes the underlying streams.

Throws:

IOException - If the stream flush causes IO problems.