Package com.google.common.geometry

Class S2RegionCoverer.ActiveCovering

java.lang.Object

com.google.common.geometry.S2RegionCoverer.ActiveCovering

Enclosing class:

S2RegionCoverer

final class S2RegionCoverer.ActiveCovering
extends Object

This class tracks the state of a covering while it is underway.

Field Summary

Fields

Modifier and Type	Field	Description
(package private) final PriorityQueue<S2RegionCoverer.QueueEntry>	candidateQueue	Prioritized candidates to explore next.
(package private) int	candidatesCreatedCounter	Counter of number of candidates created, for performance evaluation.
(package private) final boolean	interiorCovering	True if we're covering the interior.
(package private) final S2Region	region	The region being covered.
(package private) final ArrayList<S2CellId>	result	Cell ids that have been added to the covering so far.

Constructor Summary

Constructors

Constructor	Description
ActiveCovering(boolean interior, S2Region region)

Method Summary

Modifier and Type	Method	Description
private void	addCandidate(S2RegionCoverer.Candidate candidate)	Process a candidate by either adding it to the result list or expanding its children and inserting it into the priority queue.
private int	expandChildren(S2RegionCoverer.Candidate candidate, S2Cell cell, int numLevels)	Populate the children of "candidate" by expanding the given number of levels from the given cell.
private void	getCoveringInternal()	Generates a covering and stores it in result.
private void	getInitialCandidates()	Computes a set of initial candidates that cover the given region.
private int	maxChildrenShift()	Return the log base 2 of the maximum number of children of a candidate.
private S2RegionCoverer.Candidate	newCandidate(S2Cell cell)	If the cell intersects the given region, return a new candidate with no children, otherwise return null.

Methods inherited from class java.lang.Object

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

Field Details

interiorCovering

final boolean interiorCovering

True if we're covering the interior.

region

final S2Region region

The region being covered.

candidatesCreatedCounter

int candidatesCreatedCounter

Counter of number of candidates created, for performance evaluation.

result

final ArrayList<S2CellId> result

Cell ids that have been added to the covering so far.

candidateQueue

final PriorityQueue<S2RegionCoverer.QueueEntry> candidateQueue

Prioritized candidates to explore next.

Constructor Details

ActiveCovering

ActiveCovering(boolean interior,
 S2Region region)

Method Details

newCandidate

private S2RegionCoverer.Candidate newCandidate(S2Cell cell)

If the cell intersects the given region, return a new candidate with no children, otherwise return null. Also marks the candidate as "terminal" if it should not be expanded further.

maxChildrenShift

private int maxChildrenShift()

Return the log base 2 of the maximum number of children of a candidate.

addCandidate

private void addCandidate(S2RegionCoverer.Candidate candidate)

Process a candidate by either adding it to the result list or expanding its children and inserting it into the priority queue. Passing a null argument does nothing.

expandChildren

private int expandChildren(S2RegionCoverer.Candidate candidate,
 S2Cell cell,
 int numLevels)

Populate the children of "candidate" by expanding the given number of levels from the given cell. Returns the number of children that were marked "terminal".

getInitialCandidates

private void getInitialCandidates()

Computes a set of initial candidates that cover the given region.

getCoveringInternal

private void getCoveringInternal()

Generates a covering and stores it in result.