package rebelsky.vec;

/**
 * A vector in two space.
 *
 * @author CSC152 2004F
 * @version 1.0
 */
public abstract class Vec2D
{
	/** Error permitted in comparing two coordiantes. */
	private double BOUNDS = 0.0;

// +----------+-----------------------------------------------------
// | Mutators |
// +----------+


// +-----------+----------------------------------------------------
// | Observers |
// +-----------+
	/**
	 * Determine if this object equals another.
	 */
	public boolean equals(Object other)
	{
		if (other instanceof Vec2D) {
			Vec2D ovec = (Vec2D) other;
			return ((Math.abs(this.getX() - ovec.getX()) <= BOUNDS) 
				&& (Math.abs(this.getY() - ovec.getY()) <= BOUNDS));
		}
		else {
			return false;
		}
	} // equals(Object)
	
	/**
	 * Get the X coordinate of this vector.
	 */
	public abstract double getX();
	
	/**
	 * Get the Y coordinate of this vector.
	 */
	public abstract double getY();
	
	/**
	 * Get the angle of this vector from the origin.
	 */
	public abstract double getAngle();

	/**
	 * Get the radius of this vector.
	 */
	public abstract double getRadius();
	
	/**
	 * Rotate this vector for some amount around the origin.
	 */
	public abstract Vec2D rotate(double angle);

	/**
	 * Stretch this vector by some amount.
	 */
	public abstract Vec2D stretch(double factor);

	/**
	 * Compute the unit vector for this vector (radius 1, same
	 * angle).
	 */
	public abstract Vec2D unitVector();
	
	/**
	 * Convert this vector to a string.
	 */
	public abstract String toString();

} // interface Vec2D