org.das2.qstream

Class QdsToDas22

java.lang.Object

org.das2.qstream.QdsToD2sStream

org.das2.qstream.QdsToDas22

public class QdsToDas22
extends QdsToD2sStream

Write QDataSets that vary over at most 2 independent variables as a Das2 stream. Since Das2 streams can have at most 2 independent variables, higher dimensional (not necessarily higher rank) QDataSets can't be written using this code. Streams that can be written have the following plane structure X Y [Y Y Y Y ... ] X YScan [YScan YScan YScan ... ] X Y Z [Z Z Z Z ... ] All binary output is streamed in machine-native order. Since datasets written on one architecture are most likely to be read on the same architecture this choice causes the least amount of byte swapping. This is a direct serialization of QDataSet and does not require any legacy das2 dataset classes such as VectorDataset or TableDataset.

Nested Class Summary

Nested classes/interfaces inherited from class org.das2.qstream.QdsToD2sStream

QdsToD2sStream.PacketXferInfo, QdsToD2sStream.QdsXferInfo, QdsToD2sStream.Sequence1D

Field Summary

Fields inherited from class org.das2.qstream.QdsToD2sStream

bBinary, DEFAUT_FRAC_SEC, DEFAUT_SIG_DIGIT, FIXED_PKT_TAGS, FORMAT_2_2, FORMAT_2_3_BASIC, FORMAT_2_4_GENERAL, formats, nSecDigit, nSigDigit, VAR_PKT_TAGS

Constructor Summary

Constructors

Constructor and Description
QdsToDas22()
QdsToDas22(int genSigDigits, int fracSecDigits)

Method Summary

Modifier and Type	Method and Description
boolean	canWrite(QDataSet qds) Determine if a given dataset be serialized as a das2.2 stream
boolean	write(QDataSet qds, java.io.OutputStream os) Write a QDataSet as a das2.2 stream To test whether it looks like this code could stream a dataset use the canWrite() function.

Methods inherited from class org.das2.qstream.QdsToD2sStream

_stripDotProps, copySimpleProps, getQdsAxis, getSequenceRank1, makeNameFromUnits, newXmlDoc, writeData

Methods inherited from class java.lang.Object

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

Constructor Detail

QdsToDas22

public QdsToDas22()

QdsToDas22

public QdsToDas22(int genSigDigits,
                  int fracSecDigits)

Method Detail

canWrite

public boolean canWrite(QDataSet qds)

Determine if a given dataset be serialized as a das2.2 stream

Specified by:

canWrite in class QdsToD2sStream

Parameters:

qds - The dataset to write

Returns:

true if this dataset can be serialized as a das2.2 stream, false otherwise

write

public boolean write(QDataSet qds,
                     java.io.OutputStream os)
              throws java.io.IOException

Write a QDataSet as a das2.2 stream To test whether it looks like this code could stream a dataset use the canWrite() function. This function may be called multiple times to add additional data to the stream. If a compatible header has already been emitted for a particular dataset it is not re-sent.

Specified by:

write in class QdsToD2sStream

Parameters:

qds - The dataset to write, may have join's bundles etc. but no rank 3 or higher component datasets.

os - an open output stream, which is not closed by this code.

Returns:

true if the entire dataset could be written, false otherwise. IO failures do not return false, they throw. False simply means that this code does not know how (or can't) stream the given dataset. Since deeper inspection occurs when actually writing the data then when testing, false may be returned even if canWrite() returned true.

Throws:

java.io.IOException