/**
 * Class that models a jar containing black and white marbles.
 *   @author Dave Reed
 *   @version 4/9/08
 */
public class MarbleJar {
	private int numBlack;    // number of black marbles in the jar
	private int numWhite;    // number of white marbles in the jar

	/**
	 * Constructs a marble jar.
	 *   @param black number of black marbles initially in the jar
	 *   @param white number of while marbles initially in the jar
	 */
	public MarbleJar(int black, int white)
	{
		this.numBlack = black;
		this.numWhite = white;
	}

	/**
	 * Simulates drawing (and removing) a random marble from the jar.
	 *   @return the color of the drawn marble ("BLACK" or "WHITE")
	 */
	public String drawMarble() {
	    if (this.isEmpty()) {
	        return "JAR IS EMPTY";
	    }
	    else {
	        Die d = new Die(this.numBlack + this.numWhite);
	        if (d.roll() <= this.numBlack) {
	            this.numBlack--;
	            return "BLACK";
	        }
	        else {
	            this.numWhite--;
	            return "WHITE";
	        }
	    }
	}
	
	/**
	 * Determines if the jar is empty.
	 *   @return true if no marbles in the jar; else false
	 */
	public boolean isEmpty() {
	    return (this.numBlack + this.numWhite == 0);
	}
	
	/**
	 * Adds a marble to the jar.
	 *   @param color the color of the added marble ("BLACK" or "WHITE")
	 */
	public void addMarble(String color) {
	    if (color.equals("BLACK")) {
	        this.numBlack++;
	    }
	    else if (color.equals("WHITE")) {
	        this.numWhite++;
	    }
	}
}