Package uk.ac.starlink.topcat.plot2
Class CountDataStore
java.lang.Object
uk.ac.starlink.topcat.plot2.CountDataStore
- All Implemented Interfaces:
uk.ac.starlink.ttools.plot2.data.DataStore
Wrapper data store implementation used only for counting the number
of tuples requested from it.
The intention is that an operation involving data access can be
run using this data store to find out how many tuples in total
would be read by the operation. In order to run quickly however,
this implementation does not supply all those rows, it truncates
the number of tuples dispensed per sequence to a given (small) number.
When the operation is complete, the getTupleCount()
method
can be called.
- Since:
- 15 Nov 2013
- Author:
- Mark Taylor
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Constructor Summary
ConstructorsConstructorDescriptionCountDataStore
(uk.ac.starlink.ttools.plot2.data.DataStore base, int maxCount) Constructor. -
Method Summary
Modifier and TypeMethodDescriptionlong
Returns the total number of tuples represented by the tuple sequences dispensed by this data store since construction time.uk.ac.starlink.ttools.plot2.data.TupleRunner
uk.ac.starlink.ttools.plot2.data.TupleSequence
getTupleSequence
(uk.ac.starlink.ttools.plot2.data.DataSpec spec) boolean
hasData
(uk.ac.starlink.ttools.plot2.data.DataSpec spec)
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Constructor Details
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CountDataStore
public CountDataStore(uk.ac.starlink.ttools.plot2.data.DataStore base, int maxCount) Constructor.- Parameters:
base
- base data store to which most operations are delegatedmaxCount
- maximum number of tuples actually dispensed from tuplesequences acquired from this store
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Method Details
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hasData
public boolean hasData(uk.ac.starlink.ttools.plot2.data.DataSpec spec) - Specified by:
hasData
in interfaceuk.ac.starlink.ttools.plot2.data.DataStore
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getTupleSequence
public uk.ac.starlink.ttools.plot2.data.TupleSequence getTupleSequence(uk.ac.starlink.ttools.plot2.data.DataSpec spec) - Specified by:
getTupleSequence
in interfaceuk.ac.starlink.ttools.plot2.data.DataStore
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getTupleRunner
public uk.ac.starlink.ttools.plot2.data.TupleRunner getTupleRunner()- Specified by:
getTupleRunner
in interfaceuk.ac.starlink.ttools.plot2.data.DataStore
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getTupleCount
public long getTupleCount()Returns the total number of tuples represented by the tuple sequences dispensed by this data store since construction time.- Returns:
- total tuple count for non-truncated tuple sequences dispensed to date, or -1 if not known
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