org.openstreetmap.josm.data.osm

Class MultipolygonBuilder.IntersectionMatrix

java.lang.Object

org.openstreetmap.josm.data.osm.MultipolygonBuilder.IntersectionMatrix

Enclosing class:

MultipolygonBuilder

private static class MultipolygonBuilder.IntersectionMatrix
extends java.lang.Object

Helper class to avoid unneeded costly intersection calculations. If the intersection between polygons a and b was calculated we also know the result of intersection between b and a. The lookup in the hash tables is much faster than the intersection calculation.

Field Summary

Fields

Modifier and Type	Field and Description
private java.util.Map<Pair<MultipolygonBuilder.JoinedPolygon,MultipolygonBuilder.JoinedPolygon>,Geometry.PolygonIntersection>	results

Constructor Summary

Constructors

Constructor and Description
IntersectionMatrix(java.util.Collection<MultipolygonBuilder.JoinedPolygon> polygons)

Method Summary

Modifier and Type	Method and Description
(package private) Geometry.PolygonIntersection	computeIfAbsent(MultipolygonBuilder.JoinedPolygon a1, MultipolygonBuilder.JoinedPolygon a2, java.util.function.Supplier<Geometry.PolygonIntersection> computation) Returns the precomputed intersection between two polygons if known.
private Geometry.PolygonIntersection	getReverseIntersectionResult(Geometry.PolygonIntersection intersection) Compute the reverse result of the intersection test done by Geometry.polygonIntersection(Area a1, Area a2)

Methods inherited from class java.lang.Object

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

Field Detail

results

private final java.util.Map<Pair<MultipolygonBuilder.JoinedPolygon,MultipolygonBuilder.JoinedPolygon>,Geometry.PolygonIntersection> results

Constructor Detail

IntersectionMatrix

IntersectionMatrix(java.util.Collection<MultipolygonBuilder.JoinedPolygon> polygons)

Method Detail

getReverseIntersectionResult

private Geometry.PolygonIntersection getReverseIntersectionResult(Geometry.PolygonIntersection intersection)

Compute the reverse result of the intersection test done by Geometry.polygonIntersection(Area a1, Area a2)

Parameters:

intersection - the intersection result for polygons a1 and a2 (in that order)

Returns:

the intersection result for a2 and a1

computeIfAbsent

Geometry.PolygonIntersection computeIfAbsent(MultipolygonBuilder.JoinedPolygon a1,
                                             MultipolygonBuilder.JoinedPolygon a2,
                                             java.util.function.Supplier<Geometry.PolygonIntersection> computation)

Returns the precomputed intersection between two polygons if known. Otherwise perform computation.

Parameters:

a1 - first polygon

a2 - second polygon

computation - the computation to perform when intersection is unknown

Returns:

the intersection between two polygons

See Also:

Map.computeIfAbsent(K, java.util.function.Function<? super K, ? extends V>)