Class Fish

java.lang.Object
  |
  +--Fish

All Implemented Interfaces:

Locatable

Direct Known Subclasses:

DarterFish, SlowFish

public class Fish

extends java.lang.Object

implements Locatable

AP® Computer Science Marine Biology Simulation:
A Fish object represents a fish in the Marine Biology Simulation. Each fish has a unique ID, which remains constant throughout its life. A fish also maintains information about its location and direction in the environment.

Modification History: - Modified to support a dynamic population in the environment: fish can now breed and die.

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

Version:

1 July 2002

See Also:

Environment, Direction, Location

Constructor Summary

Fish(Environment env, Location loc)
Constructs a fish at the specified location in a given environment.

Fish(Environment env, Location loc, Direction dir)
Constructs a fish at the specified location and direction in a given environment.

Fish(Environment env, Location loc, Direction dir, java.awt.Color col)
Constructs a fish of the specified color at the specified location and direction.

Method Summary

void	act() Acts for one step in the simulation.
protected boolean	breed() Attempts to breed into neighboring locations.
protected void	changeDirection(Direction newDir) Modifies this fish's direction.
protected void	changeLocation(Location newLoc) Modifies this fish's location and notifies the environment.
java.awt.Color	color() Returns this fish's color.
protected void	die() Removes this fish from the environment.
Direction	direction() Returns this fish's direction.
protected java.util.ArrayList	emptyNeighbors() Finds empty locations adjacent to this fish.
Environment	environment() Returns this fish's environment.
protected void	generateChild(Location loc) Creates a new fish with the color of its parent.
int	id() Returns this fish's ID.
boolean	isInEnv() Checks whether this fish is in an environment.
Location	location() Returns this fish's location.
protected void	move() Moves this fish in its environment.
protected Location	nextLocation() Finds this fish's next location.
protected java.awt.Color	randomColor() Generates a random color.
java.lang.String	toString() Returns a string representing key information about this fish.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Constructor Detail

Fish

public Fish(Environment env,
            Location loc)

Constructs a fish at the specified location in a given environment. The Fish is assigned a random direction and random color. (Precondition: parameters are non-null; loc is valid for env.)

Parameters:

env - environment in which fish will live

loc - location of the new fish in env

Fish

public Fish(Environment env,
            Location loc,
            Direction dir)

Constructs a fish at the specified location and direction in a given environment. The Fish is assigned a random color. (Precondition: parameters are non-null; loc is valid for env.)

Parameters:

env - environment in which fish will live

loc - location of the new fish in env

dir - direction the new fish is facing

Fish

public Fish(Environment env,
            Location loc,
            Direction dir,
            java.awt.Color col)

Constructs a fish of the specified color at the specified location and direction. (Precondition: parameters are non-null; loc is valid for env.)

Parameters:

env - environment in which fish will live

loc - location of the new fish in env

dir - direction the new fish is facing

col - color of the new fish

Method Detail

randomColor

protected java.awt.Color randomColor()

Generates a random color.

Returns:

the new random color

id

public int id()

Returns this fish's ID.

Returns:

the unique ID for this fish

environment

public Environment environment()

Returns this fish's environment.

Returns:

the environment in which this fish lives

color

public java.awt.Color color()

Returns this fish's color.

Returns:

the color of this fish

location

public Location location()

Returns this fish's location.

Specified by:

location in interface Locatable

Returns:

the location of this fish in the environment

direction

public Direction direction()

Returns this fish's direction.

Returns:

the direction in which this fish is facing

isInEnv

public boolean isInEnv()

Checks whether this fish is in an environment.

Returns:

true if the fish is in the environment (and at the correct location); false otherwise

toString

public java.lang.String toString()

Returns a string representing key information about this fish.

Overrides:

toString in class java.lang.Object

Returns:

a string indicating the fish's ID, location, and direction

act

public void act()

Acts for one step in the simulation.

breed

protected boolean breed()

Attempts to breed into neighboring locations.

Returns:

true if fish successfully breeds; false otherwise

generateChild

protected void generateChild(Location loc)

Creates a new fish with the color of its parent.

Parameters:

loc - location of the new fish

move

protected void move()

Moves this fish in its environment.

nextLocation

protected Location nextLocation()

Finds this fish's next location. A fish may move to any empty adjacent locations except the one behind it (fish do not move backwards). If this fish cannot move, nextLocation returns its current location.

Returns:

the next location for this fish

emptyNeighbors

protected java.util.ArrayList emptyNeighbors()

Finds empty locations adjacent to this fish.

Returns:

an ArrayList containing neighboring empty locations

changeLocation

protected void changeLocation(Location newLoc)

Modifies this fish's location and notifies the environment.

Parameters:

newLoc - new location value

changeDirection

protected void changeDirection(Direction newDir)

Modifies this fish's direction.

Parameters:

newDir - new direction value

die

protected void die()

Removes this fish from the environment.