org.das2.qstream

Interface StreamHandler

All Known Implementing Classes:

FormatStreamHandler, MinMaxReduceFilter, NullFilter, QDataSetsFilter, QDataSetsFilter.QDataSetSink, QDataSetStreamHandler, ReduceFilter, RenderTypeFilter, StripDescriptors, ToAsciiStreamHandler, TrimStreamHandler

public interface StreamHandler

This describes an object that is able to receive a stream from StreamTool.readStream, which breaks the stream up into descriptors and packets. This was copied from das2's das2stream library to create QStream, which is to replace it. See http://das2.org/wiki/index.php/Das2/QStreams

Method Summary

Modifier and Type	Method and Description
void	packet(PacketDescriptor pd, java.nio.ByteBuffer data) receive a data packet from the stream.
void	packetDescriptor(PacketDescriptor pd) description of a new packet type.
void	streamClosed(StreamDescriptor sd) indicates the stream end is encountered.
void	streamComment(StreamComment sd) comments on the stream.
void	streamDescriptor(StreamDescriptor sd) initial description of the stream.
void	streamException(StreamException se) This is used to indicate an exception occurred in the source.

Method Detail

streamDescriptor

void streamDescriptor(StreamDescriptor sd)
               throws StreamException

initial description of the stream. This contains global properties of the stream. TODO: should codes expect only one of these? I think most probably do, but the spec says we should be able to pick up in the middle, implying that steamDescriptors may be resent.

Parameters:

sd -

Throws:

StreamException

packetDescriptor

void packetDescriptor(PacketDescriptor pd)
               throws StreamException

description of a new packet type. This packetDescriptor will also be sent as packets of data are received.

Parameters:

pd -

Throws:

StreamException

packet

void packet(PacketDescriptor pd,
            java.nio.ByteBuffer data)
     throws StreamException

receive a data packet from the stream. The packet descriptor is used to describe the packet contents, and the ByteBuffer contains the bytes. The byte buffer will have its position at the beginning of the data, and the limit will be the end of the data. Note for filters, the buffer must be reset!

Parameters:

pd - PacketDescriptor describing the data.

data - ByteBuffer containing the data.

Throws:

StreamException - when something is wrong with the content of the stream.

streamClosed

void streamClosed(StreamDescriptor sd)
           throws StreamException

indicates the stream end is encountered.

Parameters:

sd -

Throws:

StreamException

streamException

void streamException(StreamException se)
              throws StreamException

This is used to indicate an exception occurred in the source.

Parameters:

se -

Throws:

StreamException

streamComment

void streamComment(StreamComment sd)
            throws StreamException

comments on the stream.

Parameters:

sd -

Throws:

StreamException