/*
* GeoTools - The Open Source Java GIS Toolkit
* http://geotools.org
*
* (C) 2004-2008, Open Source Geospatial Foundation (OSGeo)
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation;
* version 2.1 of the License.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*/
package org.geotools.geometry;
import java.awt.geom.Point2D;
import java.io.IOException;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.io.Serializable;
import org.geotools.util.Utilities;
import org.opengis.geometry.DirectPosition;
import org.opengis.geometry.MismatchedDimensionException;
import org.opengis.referencing.crs.CoordinateReferenceSystem;
import org.opengis.util.Cloneable;
/**
* Holds the coordinates for a two-dimensional position within some coordinate reference system.
* <p>
* <b>Note 1:</b><blockquote>
* This class inherits {@linkplain #x x} and {@linkplain #y y} fields. But despite their names,
* they don't need to be oriented toward {@linkplain org.opengis.referencing.cs.AxisDirection#EAST
* East} and {@linkplain org.opengis.referencing.cs.AxisDirection#NORTH North}.
* The (<var>x</var>,<var>y</var>) axis can have any orientation and should be understood as
* "<cite>ordinate 0</cite>" and "<cite>ordinate 1</cite>" values instead. This is not specific
* to this implementation; in Java2D too, the visual axis orientation depend on the
* {@linkplain java.awt.Graphics2D#getTransform affine transform in the graphics context}.
* <p>
* The rational for avoiding axis orientation restriction is that other {@link DirectPosition}
* implementation do not have such restriction, and it would be hard to generalize (what to do
* with {@linkplain org.opengis.referencing.cs.AxisDirection#NORTH_EAST North-East} direction?).
* </blockquote>
* <p>
* <b>Note 2:</b><blockquote>
* <strong>Do not mix instances of this class with ordinary {@link Point2D} instances in a
* {@link java.util.HashSet} or as {@link java.util.HashMap} keys.</strong> It is not possible to
* meet both {@link Point2D#hashCode} and {@link DirectPosition#hashCode} contract, and this class
* choose to implements the later. Concequently, <strong>{@link #hashCode} is inconsistent with
* {@link Point2D#equals}</strong> (but is consistent with {@link DirectPosition#equals}).
* <p>
* In other words, it is safe to add instances of {@code DirectPosition2D} in a
* {@code HashSet<DirectPosition>}, but it is unsafe to add them in a {@code HashSet<Point2D>}.
* Collections that do not rely on {@link Object#hashCode}, like {@link java.util.ArrayList},
* are safe in all cases.
* </blockquote>
*
* @since 2.0
*
* @source $URL$
* @version $Id$
* @author Martin Desruisseaux (IRD)
*
* @see DirectPosition1D
* @see GeneralDirectPosition
* @see java.awt.geom.Point2D
*/
public class DirectPosition2D extends Point2D.Double implements DirectPosition, Serializable, Cloneable {
/**
* Serial number for interoperability with different versions.
*/
private static final long serialVersionUID = 835130287438466996L;
/**
* The coordinate reference system for this position;
*/
private CoordinateReferenceSystem crs;
/**
* Constructs a position initialized to (0,0) with a {@code null}
* coordinate reference system.
*/
public DirectPosition2D() {
}
/**
* Constructs a position with the specified coordinate reference system.
*
* @param crs The coordinate reference system, or {@code null}.
*/
public DirectPosition2D(final CoordinateReferenceSystem crs) {
setCoordinateReferenceSystem(crs);
}
/**
* Constructs a 2D position from the specified ordinates. Despite their name,
* the (<var>x</var>,<var>y</var>) coordinates don't need to be oriented toward
* ({@linkplain org.opengis.referencing.cs.AxisDirection#EAST East},
* {@linkplain org.opengis.referencing.cs.AxisDirection#NORTH North}).
* Those parameter names simply match the {@linkplain #x x} and {@linkplain #y y}
* fields. See the {@linkplain DirectPosition2D class javadoc} for details.
*
* @param x The <var>x</var> value.
* @param y The <var>y</var> value.
*/
public DirectPosition2D(final double x, final double y) {
super(x,y);
}
/**
* Constructs a 2D position from the specified ordinates in the specified CRS. Despite
* their name, the (<var>x</var>,<var>y</var>) coordinates don't need to be oriented toward
* ({@linkplain org.opengis.referencing.cs.AxisDirection#EAST East},
* {@linkplain org.opengis.referencing.cs.AxisDirection#NORTH North}).
* Those parameter names simply match the {@linkplain #x x} and {@linkplain #y y}
* fields. The actual axis orientations are determined by the specified CRS.
* See the {@linkplain DirectPosition2D class javadoc} for details.
*
* @param crs The coordinate reference system, or {@code null}.
* @param x The <var>x</var> value.
* @param y The <var>y</var> value.
*/
public DirectPosition2D(final CoordinateReferenceSystem crs,
final double x, final double y)
{
super(x, y);
setCoordinateReferenceSystem(crs);
}
/**
* Constructs a position from the specified {@link Point2D}.
*
* @param point The point to copy.
*/
public DirectPosition2D(final Point2D point) {
super(point.getX(), point.getY());
if (point instanceof DirectPosition) {
setCoordinateReferenceSystem(((DirectPosition) point).getCoordinateReferenceSystem());
}
}
/**
* Constructs a position initialized to the same values than the specified point.
*
* @param point The point to copy.
*/
public DirectPosition2D(final DirectPosition point) {
setLocation(point);
}
/**
* Returns always {@code this}, the direct position for this
* {@linkplain org.opengis.geometry.coordinate.Position position}.
*
* @since 2.5
*/
public DirectPosition getDirectPosition() {
return this;
}
/**
* Returns the coordinate reference system in which the coordinate is given.
* May be {@code null} if this particular {@code DirectPosition} is included
* in a larger object with such a reference to a {@linkplain CoordinateReferenceSystem
* coordinate reference system}.
*
* @return The coordinate reference system, or {@code null}.
*/
public final CoordinateReferenceSystem getCoordinateReferenceSystem() {
return crs;
}
/**
* Set the coordinate reference system in which the coordinate is given.
*
* @param crs The new coordinate reference system, or {@code null}.
*/
public void setCoordinateReferenceSystem(final CoordinateReferenceSystem crs) {
AbstractDirectPosition.checkCoordinateReferenceSystemDimension(crs, 2);
this.crs = crs;
}
/**
* The length of coordinate sequence (the number of entries).
* This is always 2 for <code>DirectPosition2D</code> objects.
*
* @return The dimensionality of this position.
*/
public final int getDimension() {
return 2;
}
/**
* Returns a sequence of numbers that hold the coordinate of this position in its
* reference system.
*
* @return The coordinates
*/
public double[] getCoordinate() {
return new double[] {x,y};
}
/**
* Returns the ordinate at the specified dimension.
*
* @param dimension The dimension in the range 0 to 1 inclusive.
* @return The coordinate at the specified dimension.
* @throws IndexOutOfBoundsException if the specified dimension is out of bounds.
*
* @todo Provides a more detailled error message.
*/
public final double getOrdinate(final int dimension) throws IndexOutOfBoundsException {
switch (dimension) {
case 0: return x;
case 1: return y;
default: throw new IndexOutOfBoundsException(String.valueOf(dimension));
}
}
/**
* Sets the ordinate value along the specified dimension.
*
* @param dimension the dimension for the ordinate of interest.
* @param value the ordinate value of interest.
* @throws IndexOutOfBoundsException if the specified dimension is out of bounds.
*
* @todo Provides a more detailled error message.
*/
public final void setOrdinate(int dimension, double value) throws IndexOutOfBoundsException {
switch (dimension) {
case 0: x=value; break;
case 1: y=value; break;
default: throw new IndexOutOfBoundsException(String.valueOf(dimension));
}
}
/**
* Set this coordinate to the specified direct position. If the specified position
* contains a {@linkplain CoordinateReferenceSystem coordinate reference system},
* then the CRS for this position will be set to the CRS of the specified position.
*
* @param position The new position for this point.
* @throws MismatchedDimensionException if this point doesn't have the expected dimension.
*/
public void setLocation(final DirectPosition position) throws MismatchedDimensionException {
AbstractDirectPosition.ensureDimensionMatch("position", position.getDimension(), 2);
setCoordinateReferenceSystem(position.getCoordinateReferenceSystem());
x = position.getOrdinate(0);
y = position.getOrdinate(1);
}
/**
* Returns a {@link Point2D} with the same coordinate as this direct position.
*
* @return This position as a point.
*/
public Point2D toPoint2D() {
return new Point2D.Double(x,y);
}
/**
* Returns a string representation of this coordinate. The default implementation formats
* this coordinate using a shared instance of {@link org.geotools.measure.CoordinateFormat}.
* This is okay for occasional formatting (for example for debugging purpose). But if there
* is a lot of positions to format, users will get better performance and more control by
* using their own instance of {@link org.geotools.measure.CoordinateFormat}.
*/
@Override
public String toString() {
return AbstractDirectPosition.toString(this);
}
/**
* Returns a hash value for this coordinate. This method implements the
* {@link DirectPosition#hashCode} contract, not the {@link Point2D#hashCode} contract.
*
* @return A hash code value for this position.
*/
@Override
public int hashCode() {
return AbstractDirectPosition.hashCode(this);
}
/**
* Compares this point with the specified object for equality. If the given object implements
* the {@link DirectPosition} interface, then the comparaison is performed as specified in its
* {@link DirectPosition#equals} contract. Otherwise the comparaison is performed as specified
* in {@link Point2D#equals}.
*
* @param object The object to compare with this position.
* @return {@code true} if the given object is equals to this position.
*/
@Override
public boolean equals(final Object object) {
/*
* If the other object implements the DirectPosition interface, performs
* the comparaison as specified in DirectPosition.equals(Object) contract.
*/
if (object instanceof DirectPosition) {
final DirectPosition other = (DirectPosition) object;
if (other.getDimension() == 2 &&
Utilities.equals(other.getOrdinate(0), x) &&
Utilities.equals(other.getOrdinate(1), y) &&
Utilities.equals(other.getCoordinateReferenceSystem(), crs))
{
assert hashCode() == other.hashCode() : this;
return true;
}
return false;
}
/*
* Otherwise performs the comparaison as in Point2D.equals(Object).
* Do NOT check the CRS if the given object is an ordinary Point2D.
* This is necessary in order to respect the contract defined in Point2D.
*/
return super.equals(object);
}
/**
* Returns a clone of this point.
*
* @return A clone of this position.
*/
@Override
public DirectPosition2D clone() {
return (DirectPosition2D) super.clone();
}
/**
* Write this object to the specified stream. This method is necessary
* because the super-class is not serializable.
*/
private void writeObject(final ObjectOutputStream out) throws IOException {
out.defaultWriteObject();
out.writeDouble(x);
out.writeDouble(y);
}
/**
* Read this object from the specified stream. This method is necessary
* because the super-class is not serializable.
*/
private void readObject(final ObjectInputStream in) throws IOException, ClassNotFoundException {
in.defaultReadObject();
x = in.readDouble();
y = in.readDouble();
}
}