org.das2.qstream

Class QDataSetStreamHandler

java.lang.Object

org.das2.qstream.QDataSetStreamHandler

All Implemented Interfaces:

StreamHandler

public class QDataSetStreamHandler
extends java.lang.Object
implements StreamHandler

reads a stream and produces QDataSets representing the data found on the stream. The stream is read in, and then getDataSet or getDataSet(name) is called to retrieve datasets.

Field Summary

Fields

Modifier and Type	Field and Description
static java.lang.String	BUILDER_JOIN_CHILDREN

Constructor Summary

Constructors

Constructor and Description
QDataSetStreamHandler()

Method Summary

Modifier and Type	Method and Description
MutablePropertyDataSet	flattenJoin(QDataSet ds) since an appended series of rank 1 datasets will return as a rank 2 join, this utility provides a standard place to flatten it.
QDataSet	getDataSet() return the default dataset for the stream.
QDataSet	getDataSet(java.lang.String name) return the dataset from the stream.
java.util.List<java.lang.String>	getDataSetNames() return a list of available datasets
java.util.Map<java.lang.String,java.lang.String>	getDataSetNamesAndDescriptions() return a list of available datasets and their label (or name if not available).
boolean	getReadPackets() if true, then packets are interpreted.
static boolean	isFlattenableJoin(QDataSet ds) If the dataset is a join of appendable datasets, then we can append them to reduce the rank by 1 and make one long time series.
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	setReadPackets(boolean val) set this is false if you just want to look at the empty dataset metadata.
void	streamClosed(StreamDescriptor sd) indicates the stream end is encountered.
void	streamComment(StreamComment se) 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.

Methods inherited from class java.lang.Object

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

Field Detail

BUILDER_JOIN_CHILDREN

public static final java.lang.String BUILDER_JOIN_CHILDREN

See Also:

Constant Field Values

Constructor Detail

QDataSetStreamHandler

public QDataSetStreamHandler()

Method Detail

getDataSetNames

public java.util.List<java.lang.String> getDataSetNames()

return a list of available datasets

Returns:

getDataSetNamesAndDescriptions

public java.util.Map<java.lang.String,java.lang.String> getDataSetNamesAndDescriptions()

return a list of available datasets and their label (or name if not available).

Returns:

streamDescriptor

public void streamDescriptor(StreamDescriptor sd)
                      throws StreamException

Description copied from interface: StreamHandler

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.

Specified by:

streamDescriptor in interface StreamHandler

Throws:

StreamException

packetDescriptor

public void packetDescriptor(PacketDescriptor pd)
                      throws StreamException

Description copied from interface: StreamHandler

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

Specified by:

packetDescriptor in interface StreamHandler

Throws:

StreamException

packet

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

Description copied from interface: StreamHandler

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!

Specified by:

packet in interface StreamHandler

Parameters:

pd - PacketDescriptor describing the data.

data - ByteBuffer containing the data.

Throws:

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

streamClosed

public void streamClosed(StreamDescriptor sd)
                  throws StreamException

Description copied from interface: StreamHandler

indicates the stream end is encountered.

Specified by:

streamClosed in interface StreamHandler

Throws:

StreamException

streamComment

public void streamComment(StreamComment se)
                   throws StreamException

Description copied from interface: StreamHandler

comments on the stream.

Specified by:

streamComment in interface StreamHandler

Throws:

StreamException

streamException

public void streamException(StreamException se)
                     throws StreamException

Description copied from interface: StreamHandler

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

Specified by:

streamException in interface StreamHandler

Throws:

StreamException

getDataSet

public QDataSet getDataSet(java.lang.String name)

return the dataset from the stream.

Parameters:

name - the name of the dataset to retrieve.

Returns:

the dataset

getDataSet

public QDataSet getDataSet()

return the default dataset for the stream. The default dataset is identified in the stream packet descriptor dataset_id attribute.

Returns:

the default dataset

setReadPackets

public void setReadPackets(boolean val)

set this is false if you just want to look at the empty dataset metadata.

Parameters:

val -

getReadPackets

public boolean getReadPackets()

if true, then packets are interpreted.

Returns:

isFlattenableJoin

public static boolean isFlattenableJoin(QDataSet ds)

If the dataset is a join of appendable datasets, then we can append them to reduce the rank by 1 and make one long time series. These datasets should be equivalent, however most of the system doesn't implement this (and probably never will). So this is a bit of a kludge, where I don't want to flatten a dataset automatically, but we probably want to.

Parameters:

ds - a join dataset of rank 2 or rank 3.

Returns:

true if the data can be joined.

flattenJoin

public MutablePropertyDataSet flattenJoin(QDataSet ds)

since an appended series of rank 1 datasets will return as a rank 2 join, this utility provides a standard place to flatten it. This will also flatten DEPENDNAME_0.

Parameters:

ds - rank 2 or 3 join dataset.

Returns:

rank 1 or 2 dataset.