edu.kzoo.grid

Class Direction

java.lang.Object

edu.kzoo.grid.Direction

public class Direction
extends java.lang.Object

AP® Computer Science Marine Biology Simulation:
The Direction class encapsulates the notion of a compass direction such as North, East, South, West.

The Direction class is copyright© 2002 College Entrance Examination Board (www.collegeboard.com).

Field Summary

Fields

Modifier and Type	Field and Description
static Direction	EAST
static int	FULL_CIRCLE Number of degrees in compass.
static Direction	NORTH
static Direction	NORTHEAST
static Direction	NORTHWEST
static Direction	SOUTH
static Direction	SOUTHEAST
static Direction	SOUTHWEST
static Direction	WEST

Constructor Summary

Constructors

Constructor and Description
Direction() Constructs a default Direction object facing North.
Direction(int degrees) Constructs a Direction object.
Direction(java.lang.String str) Constructs a Direction object.

Method Summary

Modifier and Type	Method and Description
boolean	equals(java.lang.Object other) Indicates whether some other Direction object is "equal to" this one.
int	hashCode() Generates a hash code for this direction.
int	inDegrees() Returns this direction value in degrees.
static Direction	randomDirection() Returns a random direction.
Direction	reverse() Returns the direction that is the reverse of this Direction object.
Direction	roundedDir(int numDirections, Direction startingDir) Rounds this direction to the nearest "cardinal" direction.
Direction	toLeft() Returns the direction that is a quarter turn to the left of this Direction object.
Direction	toLeft(int deg) Returns the direction that is deg degrees to the left of this Direction object.
Direction	toRight() Returns the direction that is a quarter turn to the right of this Direction object.
Direction	toRight(int deg) Returns the direction that is deg degrees to the right of this Direction object.
java.lang.String	toString() Represents this direction as a string.

Methods inherited from class java.lang.Object

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

Field Detail

NORTH

public static final Direction NORTH

NORTHEAST

public static final Direction NORTHEAST

EAST

public static final Direction EAST

SOUTHEAST

public static final Direction SOUTHEAST

SOUTH

public static final Direction SOUTH

SOUTHWEST

public static final Direction SOUTHWEST

WEST

public static final Direction WEST

NORTHWEST

public static final Direction NORTHWEST

FULL_CIRCLE

public static final int FULL_CIRCLE

Number of degrees in compass.

See Also:

Constant Field Values

Constructor Detail

Direction

public Direction()

Constructs a default Direction object facing North.

Direction

public Direction(int degrees)

Constructs a Direction object.

Parameters:

degrees - initial compass direction in degrees

Direction

public Direction(java.lang.String str)

Constructs a Direction object.

Parameters:

str - compass direction specified as a string, e.g. "North"

Throws:

java.lang.IllegalArgumentException - if string doesn't match a known direction name

Method Detail

inDegrees

public int inDegrees()

Returns this direction value in degrees.

Returns:

the value of this Direction object in degrees

equals

public boolean equals(java.lang.Object other)

Indicates whether some other Direction object is "equal to" this one.

Overrides:

equals in class java.lang.Object

Parameters:

other - the other position to test

Returns:

true if other represents the same direction; false otherwise

hashCode

public int hashCode()

Generates a hash code for this direction.

Overrides:

hashCode in class java.lang.Object

Returns:

a hash code for a Direction object

toRight

public Direction toRight()

Returns the direction that is a quarter turn to the right of this Direction object.

Returns:

the new direction

toRight

public Direction toRight(int deg)

Returns the direction that is deg degrees to the right of this Direction object.

Parameters:

deg - the number of degrees to turn

Returns:

the new direction

toLeft

public Direction toLeft()

Returns the direction that is a quarter turn to the left of this Direction object.

Returns:

the new direction

toLeft

public Direction toLeft(int deg)

Returns the direction that is deg degrees to the left of this Direction object.

Parameters:

deg - the number of degrees to turn

Returns:

the new direction

reverse

public Direction reverse()

Returns the direction that is the reverse of this Direction object.

Returns:

the reverse direction

toString

public java.lang.String toString()

Represents this direction as a string.

Overrides:

toString in class java.lang.Object

Returns:

a string indicating the direction

roundedDir

public Direction roundedDir(int numDirections,
                            Direction startingDir)

Rounds this direction to the nearest "cardinal" direction.

The choice of possible cardinal directions depends on the number of cardinal directions and the starting direction. For example, the two cardinal directions starting at NORTH are NORTH and SOUTH. The two cardinal directions starting at EAST are EAST and WEST. The four cardinal directions starting at NORTH are NORTH, EAST, SOUTH, and WEST. The four cardinal directions starting from NORTHEAST are NORTHEAST, SOUTHEAST, SOUTHWEST, and NORTHWEST. (Precondition: 0 < numDirections <= 360)

Parameters:

numDirections - the number of "cardinal" directions

startingDir - the starting cardinal direction

Returns:

the current direction rounded to a "cardinal" direction

randomDirection

public static Direction randomDirection()

Returns a random direction.

Returns:

a direction