Being.java

package ge.edu.freeuni.sdp.snake.model;

/**
 * Base class for all actors in this game: food, snakes etc. 
 * Implements only alive or dead functionality.
 */
public abstract class Being {
	
	private int _numLives;
	
	public Being(){
		// usual beings live for once.
		this(1);
	}
	
	public Being(int numLives){
		_numLives = numLives;
	}
	
	public  int getLives(){
		return _numLives;
	}
	
	public abstract BeingKind getKind();

	public final boolean isAlive() {
		return _numLives > 0;
	}

	public void kill() {
		_numLives--;
	}

	/**
	 * This method will be called by the Universe whenever head of
	 * other actor overlaps with any position occupied by this being
	 * During interaction this being is allowed to kill other being.
	 * @param other
	 */
	public abstract void interactWith(Being other);

	/**
	 * Returns true if given point is occupied by being, false otherwise. 
	 * @param point
	 * @return
	 */
	public abstract boolean contains(Point point);

	/**
	 * Returns head. Only head can eat or kill. 
	 * @return
	 */
	public abstract Point getHead();

	/**
	 * Will be called by universe. Being can change it's position inside this method.
	 * According to moving direction set and topology of the universe. 
	 * @param topology
	 */
	public abstract void move(Topology topology);

	/**
	 * Direction will be set only when being must change it's moving direction.
	 * Otherwise being must remember it's previous direction and continue moving 
	 * in that direction whenever move is called.
	 * @param direction
	 */
	public abstract void setDirection(Direction direction);
}