public class CountDataStore extends Object implements uk.ac.starlink.ttools.plot2.data.DataStore
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
can be called.
|Constructor and Description|
|Modifier and Type||Method and Description|
Returns the total number of tuples represented by the tuple sequences dispensed by this data store since construction time.
public CountDataStore(uk.ac.starlink.ttools.plot2.data.DataStore base, int maxCount)
base- base data store to which most operations are delegated
maxCount- maximum number of tuples actually dispensed from tuplesequences acquired from this store
public boolean hasData(uk.ac.starlink.ttools.plot2.data.DataSpec spec)
public uk.ac.starlink.ttools.plot2.data.TupleSequence getTupleSequence(uk.ac.starlink.ttools.plot2.data.DataSpec spec)
public long getTupleCount()
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