org.opentripplanner.model.WgsCoordinate Maven / Gradle / Ivy
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package org.opentripplanner.model;
import org.locationtech.jts.geom.Coordinate;
import org.opentripplanner.model.base.ValueObjectToStringBuilder;
import java.io.Serializable;
/**
* This class represent a OTP coordinate.
*
* This is a ValueObject (design pattern).
*/
public final class WgsCoordinate implements Serializable {
private static final String WHY_COORDINATE_DO_NOT_HAVE_HASH_EQUALS =
"Use the 'sameLocation(..)' method to compare coordinates. See JavaDoc on 'equals(..)'";
/**
* A epsilon of 1E-7 gives a precision for coordinates at equator at 1.1 cm,
* which is good enough for compering most coordinates in OTP.
*/
private static final double EPSILON = 1E-7;
private final double latitude;
private final double longitude;
public WgsCoordinate(double latitude, double longitude) {
this.latitude = latitude;
this.longitude = longitude;
}
/**
* Unlike the constructor this factory method retuns {@code null} if both {@code lat} and
* {@code lon} is {@code null}.
*/
public static WgsCoordinate creatOptionalCoordinate(Double latitude, Double longitude) {
if(latitude == null && longitude == null) { return null; }
// Set coordinate is both lat and lon exist
if(latitude != null && longitude != null) {
return new WgsCoordinate(latitude, longitude);
}
throw new IllegalArgumentException(
"Both 'latitude' and 'longitude' must have a value or both must be 'null'."
);
}
public double latitude() {
return latitude;
}
public double longitude() {
return longitude;
}
/** Return OTP domain coordinate as JTS GeoTools Library coordinate. */
public Coordinate asJtsCoordinate() {
return new Coordinate(longitude, latitude);
}
/**
* Compare to coordinates and return {@code true} if they are close together - have the
* same location. The comparison uses an EPSILON of 1E-7 for each axis, for both latitude and
* longitude.
*/
public boolean sameLocation(WgsCoordinate other) {
if (this == other) { return true; }
return isCloseTo(latitude, other.latitude) &&
isCloseTo(longitude, other.longitude);
}
/**
* Not supported, throws UnsupportedOperationException. When we compare to coordinates we want
* see if they are within a given distance, roughly within a square centimeter. This is not
* transitive, hence violating the equals/hasCode guideline. Consider 3 point along
* one of the axis:
*
* | 8mm | 8mm |
* x --- y --- z
*
* Then {@code x.sameLocation(y)} is {@code true} and {@code y.sameLocation(z)} is
* {@code true}, but {@code x.sameLocation(z)} is {@code false}.
*
* Use the {@link #sameLocation(WgsCoordinate)} method instead of equals, and never put this
* class in a Set or use it as a key in a Map.
* @throws UnsupportedOperationException if called.
*/
@Override
public boolean equals(Object obj) {
throw new UnsupportedOperationException(WHY_COORDINATE_DO_NOT_HAVE_HASH_EQUALS);
}
/**
* @throws UnsupportedOperationException if called. See {@link #equals(Object)}
*/
@Override
public int hashCode() {
throw new UnsupportedOperationException(WHY_COORDINATE_DO_NOT_HAVE_HASH_EQUALS);
}
/**
* Return a string on the form: {@code "(60.12345, 11.12345)"}. Up to 5 digits are used
* after the period(.), even if the coordinate is specified with a higher precision.
*/
@Override
public String toString() {
return ValueObjectToStringBuilder.of().addCoordinate(latitude(), longitude()).toString();
}
private static boolean isCloseTo(double a, double b) {
double delta = Math.abs(a - b);
return delta < EPSILON;
}
}