uk.ac.starlink.ttools.plot2.data

Class StepDataStore

java.lang.Object

uk.ac.starlink.ttools.plot2.data.StepDataStore

All Implemented Interfaces:

DataStore

public class StepDataStore
extends Object
implements DataStore

Wrapper data store implementation that dispenses all column data as evenly spaced subsamples by row.

Since:

13 Nov 2013

Author:

Mark Taylor

Constructor Summary

Constructors

Constructor and Description
StepDataStore(DataStore base, int step) Constructor.

Method Summary

Modifier and Type	Method and Description
TupleRunner	getTupleRunner() Returns an object that manages iteration over tuples.
TupleSequence	getTupleSequence(DataSpec spec) Returns the data described by a given DataSpec as a sequence of tuples.
boolean	hasData(DataSpec spec) Indicates whether this store has the data described by a given DataSpec.

Methods inherited from class java.lang.Object

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

Constructor Detail

StepDataStore

public StepDataStore(DataStore base,
                     int step)

Constructor.

Parameters:

base - base data store to which most behaviour is delegated

step - stride indicating the size of the subsample; step=1 means all rows, step=2 means every other one etc

Method Detail

getTupleSequence

public TupleSequence getTupleSequence(DataSpec spec)

Description copied from interface: DataStore

Returns the data described by a given DataSpec as a sequence of tuples. Must only be called if DataStore.hasData(uk.ac.starlink.ttools.plot2.data.DataSpec) returns true for the given DataSpec; if not, behaviour is undefined.

Specified by:

getTupleSequence in interface DataStore

Parameters:

spec - plot data specification object

Returns:

sequence of values which can be used to perform a plot

hasData

public boolean hasData(DataSpec spec)

Description copied from interface: DataStore

Indicates whether this store has the data described by a given DataSpec.

Specified by:

hasData in interface DataStore

Parameters:

spec - plot data specification object

getTupleRunner

public TupleRunner getTupleRunner()

Description copied from interface: DataStore

Returns an object that manages iteration over tuples. Where possible, the returned TupleRunner should be used for iteration when using this DataStore, since it contains the chosen policy for parallel execution. If only sequential processing is supported however, TupleSequences acquired from this store can be used directly.

Specified by:

getTupleRunner in interface DataStore

Returns:

tuple runner