ps2
Class Route

java.lang.Object
  ps2.Route

public class Route
extends Object

A Route is a path that traverses arbitrary GeoSegments, regardless of their names.

Routes are immutable. New Routes can be constructed by adding a segment to the end of a Route. An added segment must be properly oriented; that is, its p1 field must correspond to the end of the original Route, and its p2 field corresponds to the end of the new Route.

Because a Route is not necessarily straight, its length -- the distance traveled by following the path from start to end -- is not necessarily the same as the distance along a straight line between its endpoints.

Lastly, a Route may be viewed as a sequence of geographical features, using the getGeoFeatures() method which returns a List.

Specification Fields

• start - : GeoPoint // location of the start of the route
• end - : GeoPoint // location of the end of the route
• startHeading - : angle // direction of travel at the start of the route, in degrees
• endHeading - : angle // direction of travel at the end of the route, in degrees
• geoFeatures - : sequence // a sequence of geographic features that make up this Route
• geoSegments - : sequence // a sequence of segments that make up this Route

Derived Fields

• length : real // total length of the route, in miles
• endingGeoSegment : GeoSegment // last GeoSegment of the route

Constructor Summary

Route(GeoSegment gs)

Method Summary

Route	addSegment(GeoSegment gs) Creates a new route that is equal to this route with gs appended to its end.
boolean	equals(Object o) Compares the specified Object with this Route for equality.
GeoPoint	getEnd()
double	getEndHeading()
GeoSegment	getEndingGeoSegment()
List<GeoFeature>	getGeoFeatures() Returns a List of GeoFeature objects.
List<GeoSegment>	getGeoSegments() Returns a List of GeoSegment objects.
double	getLength()
GeoPoint	getStart()
double	getStartHeading()
int	hashCode()
String	toString()

Methods inherited from class java.lang.Object

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

Constructor Detail

Route

public Route(GeoSegment gs)

Requires:

gs != null

Effects:

Constructs a new Route.

Method Detail

getStart

public GeoPoint getStart()

Returns:

location of the start of the route

getEnd

public GeoPoint getEnd()

Returns:

location of the end of the route

getEndingGeoSegment

public GeoSegment getEndingGeoSegment()

Returns:

the last GeoSegment of the route

getStartHeading

public double getStartHeading()

Returns:

direction (in compass heading) of travel at the start of the route, in degrees

getEndHeading

public double getEndHeading()

Returns:

direction of travel at the end of the route, in degrees

getLength

public double getLength()

Returns:

total length of the route, in miles. NOTE: this is NOT as-the-crow-flies, but rather the total distance required to traverse the route. These values are not necessarily equal.

addSegment

public Route addSegment(GeoSegment gs)

Creates a new route that is equal to this route with gs appended to its end.

Returns:

a new Route r such that r.end = gs.p2 && r.endHeading = gs.heading && r.length = this.length + gs.length

Requires:

gs != null && gs.p1 = this.end

getGeoFeatures

public List<GeoFeature> getGeoFeatures()

Returns a List of GeoFeature objects. The concatenation of the GeoFeatures, in order, is equivalent to this route. No two consecutive GeoFeature objects have the same name.

Returns:

a List of GeoFeatures such that

      this.start        = a.get(0).start
   && this.startHeading = a.get(0).startHeading
   && this.end          = a.get(a.length - 1).end
   && this.endHeading   = a.get(a.length - 1).endHeading
   && this.length       =  sum (0 ≤ i < a.size) . a.get(i).length
   && for all integers i .
          (0 ≤ i < a.size - 1 ⇒ (a.get(i).name != a.get(i+1).name &&
                                       a.get(i).end   = a.get(i+1).start))
 

See Also:

GeoFeature

getGeoSegments

public List<GeoSegment> getGeoSegments()

Returns a List of GeoSegment objects. The concatentation of the GeoSegments, in order, is equivalent to this route.

Returns:

a List of GeoSegments such that

      this.start        = a.get(0).p1
   && this.startHeading = a.get(0).heading
   && this.end          = a.get( a.size - 1 ).p2
   && this.endHeading   = a.get( a.size - 1 ).heading
   && this.length       =  sum (0 ≤ i < a.size) . a.get(i).length
   && for all integers i .
          (0 ≤ i < a.size-1 ⇒ (a.get(i).p2 = a.get(i+1).p1))
 

See Also:

GeoSegment

equals

public boolean equals(Object o)

Compares the specified Object with this Route for equality.

Overrides:

equals in class Object

Returns:

true iff (o instanceof Route) && (o.geoFeatures and this.geoFeatures contain the same elements in the same order).

hashCode

public int hashCode()

Overrides:

hashCode in class Object

Returns:

a valid hash code for this.

toString

public String toString()

Overrides:

toString in class Object

Returns:

a string representation of this.