Lab 2 Lab 3 - part I

Introduction

Note! All classes at the university are cancelled between 6:00PM on Wednesday and 6:00PM on Thursday, in observance of Rosh Hashana. The traditional lab 2 and lab 3 material has been combined into a single lab, due not next week but in two weeks' time.
This page describes part I of the lab. There is nothing you must hand in after doing this work, but be sure to save your work so you can hand it in next week.

We have just begun to look at the structure of Java source code files in class. Writing those files can be an overwhelming task for students who are new to the task. You were just introduced to the lab environment in Baldy 21 and you worked briefly with Eclipse to edit a text file. In this lab, you will work a little more with Eclipse and work with the ideas we have been explored in class about the design of object oriented systems. You will build a simple program that uses the ideas we have been discussing so far in class.

Objectives

The high-level objectives of this lab are to have you,

familiarize yourself with the Eclipse environment,
use DrJava to run a small Java program, and
observe the behavior of an object oriented system.

The following are the new concepts covered in this lab:

using CVS repositories,
Eclipse environment vocabulary,
instantiating classes using the new operator, and
using the DrJava plugin.

Assignment Specifications

The basic building block of an object oriented program is the object. You have learned in class how to create an object at runtime by instantiating a class using the new operator. In this lab you will practice doing exactly that: creating instances of a pre-built class.

To make things interesting, the class you will be instantiating has some random behaviors built in. This means that something slightly different will happen each time you instantiate it.

Helpful Hints

Read through the entire lab before you start working, so that you know what to expect. Make sure you save your work often, and keep track of what you are expected to submit (next week).

Do not be afraid to refer to earlier labs to recall what things mean or what commands are available for you to use.

Reading

Make sure you have read chapter 1 of the book before coming to lab. Also make sure you have reviewed your lecture notes. It might also be helpful to begin looking at Chapter 1 of the Eclipse book.

Lab set-up tasks

At your lab session your teaching assistant will briefly discuss how to carry out each of the set-up tasks below. She or he will also be available to answer questions you might have. Before you start work on the lab itself, you must carry out each of the following set-up tasks. Your teaching assistant will guide you through this process.

Step 1: Log in

The first thing you must do when you are in the lab is log in at the SunRay in front of you. Remember that this logs you into a machine named,

styx.cse.buffalo.edu

To get access to the prompt [recall that you need the prompt to type commands to Linux], you use the Applications menu and select System Tools and then select Terminal. It is probably always a good idea to open a terminal when you log in. Recall that a terminal window looks like this:

Step 2: Start Eclipse

The second thing you need to do is start Eclipse. In Lab 1 you learned about the eclipse & command, and you also made an icon for Eclipse on your desktop. Use one of them to get Eclipse started.

Step 3: Seeing the connections to code repositories

If you do not have a tab in the lower portion of your screen that says "CVS Repositories", you should open that View so that you can see what Repositories you have connections to. To do this, select Window -> Show View -> Other. You should then select to expand the entry for CVS and select CVS Repositories and click OK. You will now see a view tab on the bottom of your screen that shows which repositories you have access to:

Step 4: Check out Lab project from LabSkeletons repository

Open the LabSkeletons repository (click on the "+" or triangle to the left of its name to "spin" it open). Open "Head", and then a dialog will pop up prompting you for your password. The password here is the same one you typed to log into the machine in Baldy 21. Type your password in and then click "OK".

Then the files in the Lab Skeletons Repository will be visible. Select Lab3:

Now right-click (on Lab3), and select "Check out".

In the left-most pane you will now see the Lab project in your workspace. You should expand out the project to see what is inside it. You will notice a package with a file named Driver.java in it.

Lab Assignment

Make an object!

Select the DrJava perspective. In the interactions pane, create an instance of the lab3.partI.Driver class (you may need to enlarge the window that opens up). Once you have finished looking at what is going on, close the window. This will cause DrJava to reset its interactions pane.

Create another instance of the lab3.partI.Driver class. Is anything different in the behavior of the program? When you are done, close the window.

Run the program as many times as you like.

Use the Eclipse text editor to create a text file in the Lab project named "PartIExplanation.txt". In that file describe in your own words what the program does. Save the file for next week.

Meet your Mentor (CSE 503 students are exempt from this part of the lab)

The non-coding portion of this lab is to attend the first meeting that your mentor is having. The mentors have collected your schedules and will be finding a meeting time that works for them as well as (most of) the people that sent him/her e-mail. As the mentors schedule times, we will post them here:

Mentor Meeting time Meeting place

Amy Evans T 2-3, R 5-6 Student Union lobby

Jacob Joyce M 3-4, T 6-7 Outside Bell 101

Jonathan Cantwell W 5-6 Flag room in student union

Kyle Carbone T 4-5, M 3-4 Capen Group Study area (basement)

Matthew Taylor M 2-3, F 2-3 Bottom floor of Capen library, by tables

Michael Hausknecht R 8-9 Baldy 121

Ka Kei (Michael) Iao T 5-6, F 10-11 Capen Cafe

Nischal Vasant T 5-6 Student Union lobby (between Putnams and the UB seal)

Rajitha Jayasinghe

Rishi Sharma F 4-6 Capen Group Study area (basement)

Russell Manzella W 5-6 Flag room in student union

Stephen Fey T 2-3, R 5-6 Student Union lobby

Tushar Saxena T 6-7 Capen Group Study area (basement)

Zeb Lohnes M 1-2, M 3-4 Baldy 21, Baldy lounge by Kiva

You should go to the meeting and find out what mentoring is all about and what kinds of information you can share as a group. Your mentor will record your attendance at this meeting and your attendance will be a portion of the lab grade for this lab.

Your mentor will be in touch via e-mail or through the course website. If you are having difficulty attending one of the mentor meetings from your recitation, please note the schedules of other mentor meetings. You can attend another mentor's meeting to gain credit for this portion of the lab. If you are having difficulties with this part of the assignment, please contact your instructor.

Note: The first meeting may actually occur after this lab is due for you. You are still required to turn in the coding portion on time. You should then attend the meeting at its scheduled time.

What you hand in

As explained in the note at the start of the lab, there is nothing for you to hand in this week.

Due dates

As explained in the note at the start of the lab, there is nothing for you to hand in this week.