com.google.uzaygezen.core

Class ListConcatCombiner<T extends Comparable<T>,V extends Content<V>,R extends Range<T,V>>

java.lang.Object

com.google.uzaygezen.core.ListConcatCombiner<T,V,R>

All Implemented Interfaces:

FilterCombiner<RangeListFilter<T,V,R>,V,R>

public class ListConcatCombiner<T extends Comparable<T>,V extends Content<V>,R extends Range<T,V>>
extends Object
implements FilterCombiner<RangeListFilter<T,V,R>,V,R>

Filter combiner that works with filters consisting in a list of ranges, and concatenates them. It only works with non-empty lists, and it never produces empty lists. And the input filters must always start and end at the boundaries of the filtered index; all filters produced by this class have that property as well.

Author:

Daniel Aioanei

Constructor Summary

Constructors

Constructor and Description
ListConcatCombiner(int threshold)

Method Summary

Methods

Modifier and Type	Method and Description
SelectiveFilter<RangeListFilter<T,V,R>>	combine(FilteredIndexRange<RangeListFilter<T,V,R>,R> lower, FilteredIndexRange<RangeListFilter<T,V,R>,R> higher, V gapEstimate) If the gap is zero, joins the last index range and the first index range into one range that covers both, and keeps the other ranges intact.
String	toString()
static <T extends Comparable<T>,V extends Content<V>,R extends Range<T,V>> ListConcatCombiner<T,V,R>	unbounded()

Methods inherited from class java.lang.Object

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

Constructor Detail

ListConcatCombiner

public ListConcatCombiner(int threshold)

Method Detail

unbounded

public static <T extends Comparable<T>,V extends Content<V>,R extends Range<T,V>> ListConcatCombiner<T,V,R> unbounded()

combine

public SelectiveFilter<RangeListFilter<T,V,R>> combine(FilteredIndexRange<RangeListFilter<T,V,R>,R> lower,
                                              FilteredIndexRange<RangeListFilter<T,V,R>,R> higher,
                                              V gapEstimate)

If the gap is zero, joins the last index range and the first index range into one range that covers both, and keeps the other ranges intact. Otherwise it concatenates the two lists of ranges. Note that we don't use the full information available in gapEstimate. Instead we extract its signum and use that to optimise the situation when the gap is zero.

Specified by:

combine in interface FilterCombiner<RangeListFilter<T extends Comparable<T>,V extends Content<V>,R extends Range<T,V>>,V extends Content<V>,R extends Range<T,V>>

Parameters:

lower - must not be empty

higher - must not be empty

gapEstimate - the estimate of the number of points in the gap between the index ranges. If zero, then it is guaranteed that there are no data points in between. If non zero, it is just an estimate and its accuracy depends on the accuracy provided by the RegionInspector in use. If the two ranges are adjacent, i.e. firstFilteredRange.getIndexRange().getEnd() == secondFilteredRange.getIndexRange().getStart(), then the gap estimate is guaranteed to be zero.

Returns:

the computed list and whether the threshold was exceeded or one of the two filters already had potential over-selectivity.

toString

public String toString()

Overrides:

toString in class Object