org.springframework.data.couchbase.repository.query.support

Class PointInShapeEvaluator

java.lang.Object

org.springframework.data.couchbase.repository.query.support.PointInShapeEvaluator

Direct Known Subclasses:

AwtPointInShapeEvaluator

public abstract class PointInShapeEvaluator
extends Object

PointInShapeEvaluator can be used to tell if a particular Point is contained by a Polygon or Circle. It is most useful to eliminate false positive when a geo query has been made using a bounding box approximation. For the purpose of this class, a point on the edge of a polygon isn't considered within it. On the contrary a point on the edge of a circle is considered in it (distance from center <= radius). To that end, additional methods that return a List of objects with false positives removed are also provided. However, these need a Converter<T, Point> to extract the location attribute that should be tested against the polygon/circle.

Author:

Simon Baslé

See Also:

for a simple implementation based on AWT standard library.

Constructor Summary

Constructors

Constructor and Description
PointInShapeEvaluator()

Method Summary

Modifier and Type	Method and Description
abstract boolean	pointInCircle(Point p, Circle c) Determine if a Point is contained by a Circle.
abstract boolean	pointInCircle(Point p, Point center, Distance radius) Determine if a Point is contained by a Circle represented by its center Point and Distance radius.
abstract boolean	pointInPolygon(Point p, Point... points) Determine if a Point is contained by a polygon represented as an array of points.
abstract boolean	pointInPolygon(Point p, Polygon polygon) Determine if a Point is contained by a Polygon.
<T> List<T>	removeFalsePositives(Collection<? extends T> boundingBoxResults, Converter<T,Point> locationExtractor, Circle circle) Utility method to remove false positives from a collection of objects that have a notion of location, where we want to only include values that are located within a circle.
<T> List<T>	removeFalsePositives(Collection<? extends T> boundingBoxResults, Converter<T,Point> locationExtractor, Point... polygon) Utility method to remove false positives from a collection of objects that have a notion of location, where we want to only include values that are located within a polygon.
<T> List<T>	removeFalsePositives(Collection<? extends T> boundingBoxResults, Converter<T,Point> locationExtractor, Point center, Distance radius) Utility method to remove false positives from a collection of objects that have a notion of location, where we want to only include values that are located within a circle.
<T> List<T>	removeFalsePositives(Collection<? extends T> boundingBoxResults, Converter<T,Point> locationExtractor, Polygon polygon) Utility method to remove false positives from a collection of objects that have a notion of location, where we want to only include values that are located within a polygon.

Methods inherited from class java.lang.Object

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

Constructor Detail

PointInShapeEvaluator

public PointInShapeEvaluator()

Method Detail

pointInPolygon

public abstract boolean pointInPolygon(Point p,
                                       Polygon polygon)

Determine if a Point is contained by a Polygon.

Parameters:

p - the point to test.

polygon - the polygon we want the point to be in.

Returns:

true if the polygon contains the point, false otherwise.

pointInPolygon

public abstract boolean pointInPolygon(Point p,
                                       Point... points)

Determine if a Point is contained by a polygon represented as an array of points. The points are not required to form a closed shape, but can (by having the first and last points be the same).

Parameters:

p - the point to test.

points - the Point[] representation of the polygon we want the point to be in.

Returns:

true if the polygon contains the point, false otherwise.

pointInCircle

public abstract boolean pointInCircle(Point p,
                                      Circle c)

Determine if a Point is contained by a Circle.

Parameters:

p - the point to test.

c - the Circle we want the point to be in.

Returns:

true if the circle contains the point, false otherwise.

pointInCircle

public abstract boolean pointInCircle(Point p,
                                      Point center,
                                      Distance radius)

Determine if a Point is contained by a Circle represented by its center Point and Distance radius.

Parameters:

p - the point to test.

center - the center Point of the Circle we want the point to be in.

radius - the Distance radius of the Circle we want the point to be in.

Returns:

true if the circle contains the point, false otherwise.

removeFalsePositives

public <T> List<T> removeFalsePositives(Collection<? extends T> boundingBoxResults,
                                        Converter<T,Point> locationExtractor,
                                        Polygon polygon)

Utility method to remove false positives from a collection of objects that have a notion of location, where we want to only include values that are located within a polygon. The collection should usually be already contained in the bounding box approximation of the polygon for maximum efficiency.

Type Parameters:

T - the type of located value objects in the collection.

Parameters:

boundingBoxResults - the collections of located objects approximately inside the target polygon.

locationExtractor - a Converter to extract the location of the value objects.

polygon - the target polygon.

Returns:

a List of the value objects which location has been verified to actually be contained within the polygon.

removeFalsePositives

public <T> List<T> removeFalsePositives(Collection<? extends T> boundingBoxResults,
                                        Converter<T,Point> locationExtractor,
                                        Circle circle)

Utility method to remove false positives from a collection of objects that have a notion of location, where we want to only include values that are located within a circle. The collection should usually be already contained in the bounding box approximation of the circle for maximum efficiency.

Type Parameters:

T - the type of located value objects in the collection.

Parameters:

boundingBoxResults - the collections of located objects approximately inside the target circle.

locationExtractor - a Converter to extract the location of the value objects.

circle - the target circle.

Returns:

a List of the value objects which location has been verified to actually be contained within the circle.

removeFalsePositives

public <T> List<T> removeFalsePositives(Collection<? extends T> boundingBoxResults,
                                        Converter<T,Point> locationExtractor,
                                        Point... polygon)

Utility method to remove false positives from a collection of objects that have a notion of location, where we want to only include values that are located within a polygon. The collection should usually be already contained in the bounding box approximation of the polygon for maximum efficiency.

Type Parameters:

T - the type of located value objects in the collection.

Parameters:

boundingBoxResults - the collections of located objects approximately inside the target polygon.

locationExtractor - a Converter to extract the location of the value objects.

polygon - the target polygon, as an array of Point (not necessarily closed).

Returns:

a List of the value objects which location has been verified to actually be contained within the polygon.

removeFalsePositives

public <T> List<T> removeFalsePositives(Collection<? extends T> boundingBoxResults,
                                        Converter<T,Point> locationExtractor,
                                        Point center,
                                        Distance radius)

Utility method to remove false positives from a collection of objects that have a notion of location, where we want to only include values that are located within a circle. The collection should usually be already contained in the bounding box approximation of the circle for maximum efficiency.

Type Parameters:

T - the type of located value objects in the collection.

Parameters:

boundingBoxResults - the collections of located objects approximately inside the target circle.

locationExtractor - a Converter to extract the location of the value objects.

center - the center of the target circle.

radius - the radius of the target circle.

Returns:

a List of the value objects which location has been verified to actually be contained within the circle.