Module org.apache.sis.referencing
Package 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 coordinate 0 and coordinate 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 met both Point2D​.hash­Code() and Direct­Position​.hash­Code() contracts, and this class chooses to implements the latter. 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:

  • Constructor Details

    • 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(Point2D p)
      Constructs a 2D position from the coordinates of the specified point. The CRS is initialized to null.
      Parameters:
      p - the point from which to copy the coordinate values.
      Since:
      1.3

    • DirectPosition2D

      public DirectPosition2D(double x, double y)
      Constructs a 2D position from the specified coordinates. 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 coordinate value (not necessarily horizontal).
      y - the second coordinate value (not necessarily vertical).

    • DirectPosition2D

      public DirectPosition2D(CoordinateReferenceSystem crs, double x, double y)
      Constructs a 2D position from the specified coordinates 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 coordinate value (not necessarily horizontal).
      y - the second coordinate 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:

    • 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 cannot be parsed.
      Mismatched­Dimension­Exception - if the given point is not two-dimensional.
      See Also:

  • Method Details

    • 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 coordinate 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 coordinate value along the specified dimension.
      Specified by:
      set­Ordinate in interface Direct­Position
      Parameters:
      dimension - the dimension for the coordinate of interest.
      value - the coordinate 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.