uk.ac.starlink.ttools.plot2.data

Class SimpleDataStoreFactory

java.lang.Object

uk.ac.starlink.ttools.plot2.data.SimpleDataStoreFactory

All Implemented Interfaces:

DataStore, DataStoreFactory

public class SimpleDataStoreFactory
extends Object
implements DataStoreFactory, DataStore

DataStoreFactory implementation that does no caching. It reads the data as required every time. This has low memory requirements. It may also be faster to use for one-pass plots, but probably not if the same column is used for multiple purposes.

Since:

11 Feb 2013

Author:

Mark Taylor

Constructor Summary

Constructors

Constructor and Description
SimpleDataStoreFactory(TupleRunner runner) 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.
DataStore	readDataStore(DataSpec[] specs, DataStore prevStore) Executes instantly and returns this object.

Methods inherited from class java.lang.Object

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

Constructor Detail

SimpleDataStoreFactory

public SimpleDataStoreFactory(TupleRunner runner)

Constructor.

Parameters:

runner - tuple runner dispensed with DataStores

Method Detail

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

readDataStore

public DataStore readDataStore(DataSpec[] specs,
                               DataStore prevStore)

Executes instantly and returns this object.

Specified by:

readDataStore in interface DataStoreFactory

Parameters:

specs - data specifications; some elements may be null

prevStore - previously obtained DataStore, or null

Returns:

new data store

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

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