EECS1030Z Test 4

Thursday March 18, 2015, 14:30-15:45
Lab 01
Version H

package test4;

import java.util.ArrayList;
import java.util.List;


/**
 * A rectangle that can move through a sequence of positions.
 * 
 * An animated rectangle has a list of positions that it can move to.
 * A client adds new positions to the list by invoking the addPosition
 * method. When the play method is invoked, the rectangle
 * moves to each position in the list starting from the first position
 * and stopping at the last position. Each time the
 * rectangle moves to a new position it is also drawn to the StdDraw instance.
 * 
 * @author EECS1030_2014_15W
 *
 */
public class AnimatedRectangle extends Rectangle {

  private List positions;

  /**
   * Create an animated rectangle whose coordinates of the lower-left corner are given
   * by position and the upper-right corner are given by
   * oppCorner.
   *
   * The list of positions contains only the initial position position.
   * 
   * @param position
   *            the coordinates of the lower-left corner of this rectangle
   * @param oppCorner
   *            the coordinates of the upper-right corner of this rectangle
   * @pre. position.getX() < oppCorner.getX() && position.getY() < oppCorner.getY()
   */
  public AnimatedRectangle(Point2D position, Point2D oppCorner) {
    super(position, oppCorner);
    this.positions = new ArrayList();
    this.positions.add(new Point2D(position));
  }

  /**
   * Returns a list of positions that are used to animate this rectangle. Modifying
   * the list returned by this method does not modify the list of
   * positions used to animate this rectangle.
   * 
   * @return a list of positions that are used to animate this rectangle
   */
  public List getPositionList() {
    return new ArrayList(this.positions);
  }

  /**
   * Add a position to the end of the list of positions used to animate this rectangle.
   * 
   * @param c the position to add
   */
  public void addPosition(Point2D c) {
    this.positions.add(c);
  }

  /**
   * Animate the rectangle by moving the rectangle to each position in its list
   * of positions starting from the first element in the list. Each time the
   * rectangle is moved it is also drawn to the StdDraw instance.
   */
  public void play() {
    for (Point2D p : this.positions) {
      this.draw();
      this.setPosition(p);
    }
  }

  /**
   * Compares this animated rectangle to the specified object. The result is
   * true if and only if the argument is not null and is an AnimatedRectangle
   * object that has the same position, opposite corner, and position list as
   * this animated rectangle.
   * 
   * @param obj
   *          the object to compare
   * @return true if the given object represents a rectangle with the same
   *         position, opposite corner, and position list as this rectangle,
   *         false otherwise
   * @see java.lang.Object#equals(java.lang.Object)
   */
  @Override
  public boolean equals(Object obj) {
    boolean eq = super.equals(obj);
    if (eq) {
      AnimatedRectangle other = (AnimatedRectangle) obj;
      int lastThis = this.positions.size() - 1;
      int lastOther = other.positions.size() - 1;
      eq = this.positions.get(0).equals(other.positions.get(0)) &&
          this.positions.get(lastThis).equals(other.positions.get(lastOther));
    }
    return eq;
  }

  /**
   * Returns a hash code for this animated rectangle.
   * 
   * @return a hash code for this animated rectangle.
   * @see test4.Rectangle#hashCode()
   */
  @Override
  public int hashCode() {
    return super.hashCode() + 31 * this.positions.hashCode();
  }

}

Other questions

public void someMethod() throws X