Release date: Tuesday, 26.06.12 - Due date: Monday, 10.07.12, 23:59

We have an implementation of a class Rectangle that stores its coordinates in two instances of the class Interval, one for the horizontal and one for the vertical extension of the Rectangle.

1. Review the code below. Give us six ideas how to improve it. If you can name a bad smell somewhere, do it. Which refactorings would you apply? We won't count the suggestion to introduce getter-methods. (Maybe you understand later why (see 3)).
2. Give us for four cases the code that we would get after your refactoring.
3. Optional! Reviewing your code after executing the refactorings, could you imagine why we suggest being reluctant concerning the introduction of getter-methods?

You can find the source code for this task (with a JUnit-test) as well in your repository in the project A12T01_Refactoring.

package gui;
import model.Rectangle;

public class View {
  public Rectangle rectangle;
  public void redraw() {
    System.out.println(rectangle);
  }
}

package model;
import static java.lang.Math.*;
import gui.View;

public class Rectangle {

  private Interval horizontal;
  private Interval vertical;
  private View view;

  public Rectangle(View view, int startX, int startY, int endX, int endY) {
    if ((startX > endX) || (startY > endY))
      throw new IllegalArgumentException("Parameters in wrong order.");
    this.horizontal = new Interval(startX, endX);
    this.vertical = new Interval(startY, endY);
    this.view = view; view.rectangle = this;
  }

  /**
   * Create an empty Rectangle with no location.
   */
  public Rectangle(View view) {
    this.horizontal = null;
    this.vertical = null;
    this.view = view; view.rectangle = this;
  }
 
  public Vertex getCenter() {
    if (horizontal == null)
      return null;
    return new Vertex((horizontal.start + horizontal.end) / 2,
        (vertical.start + vertical.end) / 2);
  }

  public boolean contains(Rectangle parameter) {
    if (parameter.horizontal == null)
      return false;
    if (horizontal == null)
      return false;
    // check whether the horizontal interval
    // contains the horizontal interval
    // in the other rectangle
    // AND
    // check whether the vertical interval
    // contains the vertical interval
    // in the other rectangle
    return ((horizontal.start <= parameter.horizontal.start) 
      && (parameter.horizontal.end <= horizontal.end))
      && ((vertical.start <= parameter.vertical.start) 
      && (parameter.vertical.end <= vertical.end));
  }

  /**
   * Enlarge the Rectangle just enough so that it contains the other
   * Rectangle. If the Rectangle was empty it gets the same extension
   * as the other Rectangle.
   */
  public void accommodate(Rectangle other) {
    if ((other == null) || (other.horizontal == null))
      return;
    if (horizontal == null) {
      horizontal = new Interval(other.horizontal);
      vertical = new Interval(other.vertical);
      return;
    }
    horizontal.start = min(other.horizontal.start, horizontal.start);
    horizontal.end = max(other.horizontal.end, horizontal.end);
    vertical.start = min(other.vertical.start, vertical.start);
    vertical.end = max(other.vertical.end, vertical.end);
    view.redraw();	
  }

  public boolean equals(Object obj) {
    if (!(obj instanceof Rectangle))
      return false;
    Rectangle other = (Rectangle) obj;
    if (horizontal == null)
      return (other.horizontal == null);
    return (horizontal.equals(other.horizontal))
        && (vertical.equals(other.vertical));
  }

  public String toString() {
    return "Rectangle(" + horizontal + " x " + vertical + ")";
  }
}

Decide whether the following statements are correct or wrong. Give the answer and a short explanation (1-2 sentences) in a text file.

Evaluation: For this assignment you get 0,5 points for every correct answer with a reasonable explanation. During the final exam you get +1 point for every correct answer and -1 point for every incorrect answer. The minimal number of points for each of the section is 0, this means e.g. giving three incorrect answers in the first block does not influence the points for the second block.

public void methodA(){
   if (...) { ... } else { ... }
   if (...) { ... } else { ... } 
}	

  
public void methodB(){
   if (...) { 
      if (...) { ... } else { ... } 
   } else { 
     ... 
   } 
}