• Complete the method moveRocketBy(). The method should move the rocket upwards by the amount given by the method's argument. In other words, the method needs to change the y-positions of the parts of the rocket.

  To do this, first set the nose position, and then set the body and jet positions relative to the nose and body, respectively. You must make use of the methods you wrote for part a., as well as other methods.

  Test your method moveRocketBy() in the OUWorkspace, using the test code included in the README.TXT file for this project, to check that the rocket moves up and down correctly.

  (3 marks)

• c.Complete the methods pulse1(), pulse2() and pulse3(), as described below.
  • i.The pulse1() method should do the following:
  • set the diameter of jet to 6
  • reset the position of the jet (because its size is now different, and we want it to stay centred underneath the body)
  • set the colour of jet to red.
  • ii.The pulse2() method should do the following:
  • set the diameter of jet to 12
  • reset the position of the jet (because its size is now different, and we want it to stay centred underneath the body)
  • set the colour of jet to orange.
  • iii.The pulse3() method should do the following:
  • set the diameter of jet to 24
  • reset the position of the jet (because its size is now different, and we want it to stay centred underneath the body)
  • set the colour of jet to red.

  To test your completed methods, execute the statements in part a. to create an instance of Rocket.

  Execute the next three lines of code, which are included in the README.TXT file for this project, one line at a time observing the results in the Graphical Display:

  • r.pulse1();
  • r.pulse2();
  • r.pulse3();

public class Rocket { private Triangle nose; // represents the rocket's nose cone private Square body; // represents the rocket's body private Circle jet; // represents the blast from the rocket's engine

/** * Constructor for objects of class Rocket */ public Rocket(Triangle t, Square s, Circle c) { //first, we store references to the workspace shape objects this.nose = t; this.body = s; this.jet = c;

//sets the initial positions of the nose. //The other parts need to be set relative to these positions. this.nose.setXPos(50); this.nose.setYPos(300);

//sets the body relative to the nose, using the helper methods this.body.setXPos(getBodyXPos()); this.body.setYPos(getBodyYPos());

//The jet is invisible to begin with, because it uses //the background colour of WHITE, but you can use BLACK //to help you see it while testing this.jet.setColour(OUColour.WHITE); this.jet.setDiameter(10);

//sets the jet position relative to the body, using the helper methods this.jet.setXPos(getJetXPos()); this.jet.setYPos(getJetYPos()); }

private int getBodyXPos() { //to be written in Q1(a)(i) return 0; }

private int getBodyYPos() { //to be written in Q1(a)(ii) return 0; } private int getJetXPos() { //to be written in Q1(a)(iii) return 0; }

private int getJetYPos() { //to be written in Q1(a)(iv) return 0; }

/** * Moves the nose of the receiver * by anInt units. * Moves other rocket components relative to the * position of the nose. */ public void moveRocketBy(int anInt) { //to be written in Q1(b) }

/** * Sets the diameter of the receiver's jet to * 6, alters its xPos so its centre aligns with the body centre * and sets its colour to red. */ public void pulse1() { //to be written in Q1(c)(i) }

/** * Sets the diameter of the receiver's jet to * 12, alters its xPos so its centre aligns with the body centre * and sets its colour to orange. */ public void pulse2() { //to be written in Q1(c)(ii) }

/** * Sets the diameter of the receiver's jet to * 24, alters its xPos so its centre aligns with the body centre * and sets its colour to red. */ public void pulse3() { //to be written in Q1(c)(iii) }

/** * Simulates the ignition of the rocket's jets */ public void ignition() { //to be written in Q1(d) }

/** * Moves the entire rocket in a loop repeated * 100 times, animating the jet as it goes, so the rocket * moves upwards by speed units every 4th iteration */ public void animateRocket(int speed) { //to be written in Q1(e) }

/** * Prompts the user to enter the number of units they want the * rocket to move upwards at a time (speed) * * If the number of units provided would eventually cause the tip of the * nose to go past the top of the Graphical Display, the user * is informed via a dialogue box that the rocket will not launch. * * Otherwise the rocket launches as required. */ public void launch() { //to be written in Q1(f) }

/** * Causes execution to pause by time number of milliseconds */ public void delay(int time) { try { Thread.sleep(time); } catch (Exception e) { System.out.println(e);