org.apache.sis.geometry

Class DirectPosition2D

Object

Point2D

Point2D.Double

DirectPosition2D

All Implemented Interfaces:

Serializable, Cloneable, Position, DirectPosition

public class DirectPosition2D
extends Point2D.Double
implements DirectPosition, Cloneable

A two-dimensional position on top of Java2D point. This implementation is provided for inter-operability between Java2D and GeoAPI.

This class inherits x and y fields. But despite their names, they don't need to be oriented toward East and North respectively. The (x,y) axis can have any direction and should be understood as ordinate 0 and ordinate 1 values instead. This is not specific to this implementation; in Java2D too, the visual axis orientation depend on the affine transform in the graphics context.

Note: The rational for avoiding axis orientation restriction is that other Direct­Position implementations do not have such restriction, and it would be hard to generalize. For example there is no clear "x" or "y" classification for North-East direction.

Caution when used in collections

Do not mix instances of this class with ordinary Point2D instances in a Hash­Set or as Hash­Map keys. It is not possible to meet both Point2D.hash­Code() and Direct­Position.hash­Code() contracts, and this class chooses to implements the later. Consequently, the hash­Code() method of this class is inconsistent with Point2D.equals(Object) but is consistent with Direct­Position.equals(Object).

In other words, it is safe to add instances of Direct­Position2D in a Hash­Set<Direct­Position>, but it is unsafe to add them in a Hash­Set<Point2D>. Collections that do not rely on hash codes, like Array­List, are safe in all cases.

Since:

0.3

See Also:

Direct­Position1D, General­Direct­Position, Point2D, Coordinate­Format, Serialized Form

Defined in the sis-referencing module

Nested Class Summary

Nested classes/interfaces inherited from class Point2D

Point2D.Double, Point2D.Float

Field Summary

Fields inherited from class Point2D.Double

x, y

Constructor Summary

Constructors

Constructor and Description
DirectPosition2D() Constructs a position initialized to (0,0) with a null coordinate reference system.
DirectPosition2D(CharSequence wkt) Constructs a position initialized to the values parsed from the given string in Well Known Text (WKT) format.
DirectPosition2D(CoordinateReferenceSystem crs) Constructs a position initialized to (0,0) with the specified coordinate reference system.
DirectPosition2D(CoordinateReferenceSystem crs, double x, double y) Constructs a 2D position from the specified ordinates in the specified CRS.
DirectPosition2D(DirectPosition position) Constructs a position initialized to the same values than the specified point.
DirectPosition2D(double x, double y) Constructs a 2D position from the specified ordinates.

Method Summary

Modifier and Type	Method and Description
DirectPosition2D	clone() Returns a clone of this point.
boolean	equals(Object object) Compares this point with the specified object for equality.
double[]	getCoordinate() Returns a sequence of numbers that hold the coordinate of this position in its reference system.
CoordinateReferenceSystem	getCoordinateReferenceSystem() Returns the coordinate reference system in which the coordinate is given.
int	getDimension() The length of coordinate sequence (the number of entries).
DirectPosition	getDirectPosition() Returns always this, the direct position for this position.
double	getOrdinate(int dimension) Returns the ordinate at the specified dimension.
int	hashCode() Returns a hash value for this coordinate.
void	setCoordinateReferenceSystem(CoordinateReferenceSystem crs) Sets the coordinate reference system in which the coordinate is given.
void	setLocation(Point2D position) Sets this coordinate to the specified point.
void	setOrdinate(int dimension, double value) Sets the ordinate value along the specified dimension.
String	toString() Formats this position in the Well Known Text (WKT) format.

Methods inherited from class Point2D.Double

get­X, get­Y, set­Location

Methods inherited from class Point2D

distance, distance, distance, distance­Sq, distance­Sq, distance­Sq

Methods inherited from class Object

finalize, get­Class, notify, notify­All, wait, wait, wait

Constructor Detail

DirectPosition2D

public DirectPosition2D()

Constructs a position initialized to (0,0) with a null coordinate reference system.

DirectPosition2D

public DirectPosition2D(CoordinateReferenceSystem crs)

Constructs a position initialized to (0,0) with the specified coordinate reference system.

Parameters:

crs - the coordinate reference system, or null.

DirectPosition2D

public DirectPosition2D(double x,
                        double y)

Constructs a 2D position from the specified ordinates. Despite their names, the (x,y) coordinates don't need to be oriented toward (East, North). Those parameter names simply match the x and y fields. See the class javadoc for details.

Parameters:

x - the first ordinate value (not necessarily horizontal).

y - the second ordinate value (not necessarily vertical).

DirectPosition2D

public DirectPosition2D(CoordinateReferenceSystem crs,
                        double x,
                        double y)

Constructs a 2D position from the specified ordinates in the specified CRS. Despite their names, the (x,y) coordinates don't need to be oriented toward (East, North). Those parameter names simply match the x and y fields. The actual axis orientations are determined by the specified CRS. See the class javadoc for details.

Parameters:

crs - the coordinate reference system, or null.

x - the first ordinate value (not necessarily horizontal).

y - the second ordinate value (not necessarily vertical).

DirectPosition2D

public DirectPosition2D(DirectPosition position)
                 throws MismatchedDimensionException

Constructs a position initialized to the same values than the specified point.

Parameters:

position - the position to copy.

Throws:

Mismatched­Dimension­Exception - if the given position is not two-dimensional.

See Also:

set­Location(Point2D)

DirectPosition2D

public DirectPosition2D(CharSequence wkt)
                 throws IllegalArgumentException

Constructs a position initialized to the values parsed from the given string in Well Known Text (WKT) format. The given string is typically a POINT element like below:

POINT(6 10)

Parameters:

wkt - the POINT or other kind of element to parse.

Throws:

Illegal­Argument­Exception - if the given string can not be parsed.

Mismatched­Dimension­Exception - if the given point is not two-dimensional.

See Also:

to­String(), Coordinate­Format

Method Detail

getDirectPosition

public final DirectPosition getDirectPosition()

Returns always this, the direct position for this position.

Specified by:

get­Direct­Position in interface Position

getDimension

public final int getDimension()

The length of coordinate sequence (the number of entries). This is always 2 for Direct­Position2D objects.

Specified by:

get­Dimension in interface Direct­Position

Returns:

the dimensionality of this position.

getCoordinateReferenceSystem

public final CoordinateReferenceSystem getCoordinateReferenceSystem()

Returns the coordinate reference system in which the coordinate is given. May be null if this particular Direct­Position is included in a larger object with such a reference to a CRS.

Specified by:

get­Coordinate­Reference­System in interface Direct­Position

Returns:

the coordinate reference system, or null.

setCoordinateReferenceSystem

public void setCoordinateReferenceSystem(CoordinateReferenceSystem crs)

Sets the coordinate reference system in which the coordinate is given.

Parameters:

crs - the new coordinate reference system, or null.

getCoordinate

public final double[] getCoordinate()

Returns a sequence of numbers that hold the coordinate of this position in its reference system.

API note: This method is final for ensuring consistency with the x and y fields, which are public.

Specified by:

get­Coordinate in interface Direct­Position

Returns:

the coordinate.

getOrdinate

public final double getOrdinate(int dimension)
                         throws IndexOutOfBoundsException

Returns the ordinate at the specified dimension.

API note: This method is final for ensuring consistency with the x and y fields, which are public.

Specified by:

get­Ordinate in interface Direct­Position

Parameters:

dimension - the dimension in the range 0 to 1 inclusive.

Returns:

the coordinate at the specified dimension.

Throws:

Index­Out­Of­Bounds­Exception - if the specified dimension is out of bounds.

setOrdinate

public void setOrdinate(int dimension,
                        double value)
                 throws IndexOutOfBoundsException

Sets the ordinate value along the specified dimension.

Specified by:

set­Ordinate in interface Direct­Position

Parameters:

dimension - the dimension for the ordinate of interest.

value - the ordinate value of interest.

Throws:

Index­Out­Of­Bounds­Exception - if the specified dimension is out of bounds.

setLocation

public void setLocation(Point2D position)

Sets this coordinate to the specified point. If the specified position is also a Direct­Position containing a non-null coordinate reference system (CRS), then the CRS for this position will be set to the CRS of the given point.

Overrides:

set­Location in class Point2D

Parameters:

position - the new position for this point.

toString

public String toString()

Formats this position in the Well Known Text (WKT) format. The output is like below:

POINT(x y)

The string returned by this method can be parsed by the Direct­Position2D constructor.

Overrides:

to­String in class Point2D.Double

hashCode

public int hashCode()

Returns a hash value for this coordinate. This method implements the Direct­Position.hash­Code() contract, not the Point2D.hash­Code() contract.

Specified by:

hash­Code in interface Direct­Position

Overrides:

hash­Code in class Point2D

Returns:

a hash code value for this position.

equals

public boolean equals(Object object)

Compares this point with the specified object for equality. If the given object implements the Direct­Position interface, then the comparison is performed as specified in the Direct­Position.equals(Object) contract. Otherwise the comparison is performed as specified in the Point2D.equals(Object) contract.

Specified by:

equals in interface Direct­Position

Overrides:

equals in class Point2D

Parameters:

object - the object to compare with this position.

Returns:

true if the given object is equal to this position.

clone

public DirectPosition2D clone()

Returns a clone of this point.

Overrides:

clone in class Point2D

Returns:

a clone of this position.