uk.ac.starlink.ttools.plot2.layer

Class BinListCollector

java.lang.Object

uk.ac.starlink.ttools.plot2.layer.BinListCollector

All Implemented Interfaces:

SplitCollector<TupleSequence,BinList>

public abstract class BinListCollector
extends Object
implements SplitCollector<TupleSequence,BinList>

Partial SplitCollector implementation for accumulating data in BinLists.

Since:

27 Sep 2019

Author:

Mark Taylor

Constructor Summary

Constructors

Constructor and Description
BinListCollector(Combiner combiner, long nbin) Constructor.

Method Summary

Modifier and Type	Method and Description
BinList	combine(BinList binList1, BinList binList2) Combines the content of two accumulators.
BinList	createAccumulator() Returns a new accumulator into which results can be collected.
static BinList	createDefaultBinList(Combiner combiner, long size) Returns a BinList implementation suitable for a given number of bins and a given combiner.
static BinList	mergeBinLists(BinList binList1, BinList binList2) Returns a BinList with contents corresponding to the aggregation of two input BinLists.

Methods inherited from class java.lang.Object

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

Methods inherited from interface uk.ac.starlink.util.SplitCollector

accumulate

Constructor Detail

BinListCollector

public BinListCollector(Combiner combiner,
                        long nbin)

Constructor.

Parameters:

combiner - combination mode

nbin - bin index limit

Method Detail

createAccumulator

public BinList createAccumulator()

Description copied from interface: SplitCollector

Returns a new accumulator into which results can be collected. Accumulator instances may only be used from one thread at any one time.

Specified by:

createAccumulator in interface SplitCollector<TupleSequence,BinList>

Returns:

new accumulator

combine

public BinList combine(BinList binList1,
                       BinList binList2)

Description copied from interface: SplitCollector

Combines the content of two accumulators. The returned value may or may not be the same object as one of the input values. The input values should not be used following this call. The sequence of the input values is not significant.

Specified by:

combine in interface SplitCollector<TupleSequence,BinList>

Parameters:

binList1 - one input accumulator

binList2 - other input accumulator

Returns:

accumulator containing the combined result of the inputs

createDefaultBinList

public static BinList createDefaultBinList(Combiner combiner,
                                           long size)

Returns a BinList implementation suitable for a given number of bins and a given combiner. This may return an implementation based on a hash, or an array, or some combination.

Parameters:

combiner - combiner

size - maximum number of bins

mergeBinLists

public static BinList mergeBinLists(BinList binList1,
                                    BinList binList2)

Returns a BinList with contents corresponding to the aggregation of two input BinLists. The result is the same as if all the data submitted to the input bin lists had instead been submitted to the output one. The result may or may not be the same object as one of the inputs. The inputs should not be used following this operation.

This method will work for any BinList instances, but it is intended for use with BinLists generated by createDefaultBinList.

Parameters:

binList1 - first input

binList2 - second input

Returns:

aggregation of the inputs