Notes From Class

Week 1: January 26 and 28, 2005

If you do not have a Glue computer account, please get one. See the FAQ's for step-by-step instructions.
If you can't find Austin/Chancogne at the local bookstore, you can buy it online. For a list of online bookstores and prices, see BookHQ.

Week 2: January 31. February 2 and 4, 2005

I have put your picture on the meet the class page. If you have any objections (e.g., the mug shot isn't up to your usual GQ/Vogue standards), please let me know.
You can test the speed of your internet connection with http://www.dslreports.com/stest .

Week 3: February 7, 9 and 11, 2005

If you need a good terminal emulator for your home PC, go http://www.tucows.com and search on "Term CRT." Take a look at "CRT 4.1.8" -- at home I have an earlier version and I think it's great.

If you have downloaded the bulletproof FTP program to your PC at home, you'll need the IP addresses for wam and glue to insert into the site manager (which is on the left-most pulldown menu). The IP addresses are as follows:

    Site                                  IP addresses
    --------------------------------------------------
    wam.umd.edu                           128.8.10.141
                                          128.8.10.142
                                          128.8.10.143

    glue.umd.edu                           128.8.10.68
                                           128.8.10.71
    --------------------------------------------------

Starting Feb. 10, the class reader is available at the Engineering Copy Center. The cost is $15.00.
The Global Reach Organization reports on Internet Statistics by language. As of 2004, there are 803 million users on the Internet. But here's the surprise, only 287 million of them are English speaking. There are approximately 35 million domain names and 171 million host computers.

Week 4: February 14, 16 and 18, 2005

Homework 1 is available.
Need to find an open lab to do your homework? There are a couple of dozen locations, including the ground floor of Glen Martin Hall and 1120 AVW.

Week 5: February 21, 23 and 25, 2005

We are moving onto Java -- please read Chapter 16 of the class text, Austin/Chancogne.
Take a look at the Library of Programs that use Java Swing and Java 2D from ENCE 489C: Engineering Software Development.

Week 7: March 7, 9 and 11, 2005

On Monday we covered object-oriented program design. Please read chapter 17 of Austin/Chancogne.
On Wednesday we covered two simple Java programs .
Midterm 1 (25%): March 11. Closed book. The midterm will cover Chapters 1 and 2 of the class text, introduction to object-oriented programming concepts and Java, and anything that was written on the board during the first seven weeks of class.

Week 8: March 14, 16 and 18, 2005

Read sections 18.1 - 18.3 in Austin/Chancogne.
I have almost finished grading Midterm 1. I want to spend classtime this week covering material that is in homework 2, and will go over the midterm, Monday after spring break.
Homework 2. Solve problems 3.1, 3.2 and 3.3 in the "Java Programming Exercises" handout.
Available formats: Acrobat ( pdf ), Postscript ( ps ).
Hints. In problems 3.2 and 3.3 you will need to prompt a user for input from the keyboard -- you should use the method keyboardInput() to read a line of text from the keyboard and return it to the calling program as a string. For the relevant details, see pg. 134 of the class handout. See sections 18.11.9 and 18.11.10 in Austin/Chancogne for an explanation of keyboardInput() and the process of converting the string to an appropriate numerical format.
For each problem, hand in a copy of your program source code and a script file showing the I/O of typical program runs.
Due date: March 18, 9am.

Week 9: March 21, 23 and 25, 2005

Spring break -- no class...

Week 10: March 28 and 30. April 1, 2005

Monday -- hand back midterm 1. Go over each question in detail.
Homework 3. Solve problems 3.6, 3.7 and 3.8 in the "Java Programming Exercises" handout.
Available formats: Acrobat ( pdf ), Postscript ( ps ).
For each problem, hand in a copy of your program source code and a script file showing the I/O of typical program runs.
Due date: April 6, 9am.

Week 11: April 4, 6 and 8, 2005

If you couldn't make it to class on Monday, we finished the topic of "branching and looping" constructs. The relevant reading is Section 18.7 in Austin/Chancogne.
The topic for Wednesday is "strings and arrays". The relevant reading is pg's 526-528 of Austin/Chancogne and Java Handouts 4 and 5 in the class reader.

As I mentioned in class, I have created a small java program to print floating-point and integer numbers in a tidy table, e.g.,

prompt >>
prompt >> java TidyTable
   number left                right
========= ============ ============
     0/7: 0.0000             0.0000
     1/7: 0.1429             0.1429
    11/7: 1.5714             1.5714
   111/7: 15.8571           15.8571
  1111/7: 158.7143         158.7143
-11111/7: -1587.2856     -1587.2856

       0: 0                       0
      10: 10                     10
    1000: 1000                 1000
-1000000: -1000000         -1000000
========= ============ ============
prompt >>

The source code is: TidyTable.java We will use the doubleToString() and integerToString() methods in homework 4.

Weeks 12 and 13: April 11 through 22, 2005

On Monday we will start the topic of "classes and objects". This is the most important part of Java programming, so please make every effort to come to class!!!

Download the source code files for Circle.java and ColoredCircle.java and compile and run them. You should find that the output for Circle is:

prompt >> java Circle
Wheel 1: Center is at (1.0,2.0): Radius = 2.0

Wheel 2: Center is at (5.0,3.0): Radius = 3.0
Wheel 2: Perimeter = 18.84955592153876
Wheel 2: Area      = 28.274333882308138
prompt >>

Read pg's 511-515 of Austin/Chancogne.

Homework 4 is due on April 27.
Question 4.1. The two files that you will need are Complex.java and Quadratic.java .
After you have downloaded these files to your account, you can compile the program by simply typing:
```
     javac Quadratic.java
```
Then start to fill in the missing details. As with the previous assignments, please hand in a copy of the program source code (i.e., Quadratic.java) and a script file showing I/O for a couple of typical program runs.
Question 4.2. Download the file DataMatrix.java and fill in the missing details in method print(). When you run the completed program, the output should look something like:
```
prompt >> java DataMatrix
Matrix: A
1.0E-4  2.0  0.0  0.0  
0.0  2.0  -23.0  -3000.0  
0.0  0.0  13.0  -140.0  


Matrix: B
row/col             1          2
1            -2785.02     126.44
2            -3680.37   -2016.06

Matrix: C
row/col             1          2          3          4          5          6
1               0.000      4.000      8.000     12.000     16.000     20.000
2              -9.999     -5.999     -1.999      2.000      6.000     10.000
3             -19.999    -15.999    -11.999     -7.999     -3.999      0.000
4             -29.999    -25.999    -21.999    -17.999    -13.999     -9.999
5             -39.999    -35.999    -31.999    -27.999    -23.999    -19.999

Matrix: C
row/col             7          8          9         10
1              24.000     28.000     32.000     36.000
2              14.000     18.000     22.000     26.000
3               4.000      8.000     12.000     16.000
4              -5.999     -1.999      2.000      6.000
5             -15.999    -11.999     -7.999     -3.999
prompt >>
```
Question 4.3. The adjacent figure shows how triangles can be modeled using Vector, Node, Edge and Triangle classes.

The class Vector models two dimensional vectors characterised by (x,y) coordinate pairs. The class Node extends Vector. It adds a name. An edge line segment is characterised by its two "node" end points (i.e., The class Edge uses instances of class Node). Finally, the class Triangle uses three instances of class Node and three instances of class Edge.
To get started, download and compile the files Vector.java , Node.java , Edge.java and Triangle.java . These four files are the solution to homework 4, Fall Semester 2004, plus a code outline for testing whether a point lies inside/outside a triangle. Output from the complete program should look something like:
```
Test output with toString() method
Triangle: "null"
================================= 
Edge("e1") connects nodes (n3, n1)
Edge("e2") connects nodes (n1, n2)
Edge("e3") connects nodes (n2, n3)
Node("n3") is at (3.0,0.0)
Node("n1") is at (3.0,4.0)
Node("n2") is at (0.0,0.0)
================================= 

Perimeter = 12.0
Area      = 6.0

Test pointInsideTriangle() method ...
*** Point (1,1) is INSIDE triangle
*** Point (3,1) is INSIDE triangle
*** Point ( 3.5, 1) is OUTSIDE triangle
*** Point (-3,1) is OUTSIDE triangle
```
Fill in the missing details in the pointInsideTriangle() method.
Related Hint. Paul Burke has prepared a nice discussion of this problem together with three solution approaches.

Week 14: April 25, 27 and 29, 2005
- Midterm 2 (25%): April 29. Open book and open notes. The midterm will cover object-oriented and programming concepts in Java, the homeworks, and anything that was written on the board during the first 12 weeks of class.
Week 15: May 2, 4 and 6, 2005
- Introduction to ArrayLists
  Most models of engineering applications need to work with collections of objects whose size may change over time. The standard array data structure is good for storing groups of objects of fixed size, but performs poorly when the number of items changes a lot and/or objects need to be kept in order. We need easy-to-use facilities for assembling lists, retrieving items from the list, keeping the list items in order, printing objects, and so forth.
  The ArrayList class in Java provides facilities for building lists of generic objects. To see how the class Arraylist works in practice, please download, compile, and run the files ArrayTest1.java , ArrayTest2.java , Triangle.java , Edge.java , and Node.java .
  Program ArrayTest1 builds/prints a list of strings and then incrementally assembles a list of polygon edges and vertices. Finally, we use the java Iterator to walk along the polygon edges and compute the perimeter. The output is as follows:
```
Walk along list and print strings
=================================
Name = node 1
Name = node 2
Name = node 3
Name = node 4
Name = node 5

Polygon node list
====================================
Node("p1") is at (0.0,0.0)
Node("p2") is at (5.0,0.0)
Node("p3") is at (5.0,5.0)
Node("p4") is at (2.5,7.0)
Node("p5") is at (0.0,5.0)
Node("p6") is at (0.0,0.0)
====================================

Polygon edge list
====================================
Edge("e1") connects nodes (p1, p2)
Edge("e2") connects nodes (p2, p3)
Edge("e3") connects nodes (p3, p4)
Edge("e4") connects nodes (p4, p5)
Edge("e5") connects nodes (p5, p6)
Edge("e6") connects nodes (p6, p1)
====================================
Polygon perimeter = 21.40312423743285
====================================
```
  Program ArrayTest2 builds a list of three triangles, adds them to a list, and then walks along the list printing contents of each object in a string format. The output is as follows:
```
Print triangles
=================================
Triangle: "A"
=================================
Edge("e1") connects nodes (n3, n1)
Edge("e2") connects nodes (n1, n2)
Edge("e3") connects nodes (n2, n3)
Node("n3") is at (3.0,0.0)
Node("n1") is at (3.0,4.0)
Node("n2") is at (0.0,0.0)
=================================

Triangle: "C"
=================================
Edge("e1") connects nodes (n3, n1)
Edge("e2") connects nodes (n1, n2)
Edge("e3") connects nodes (n2, n3)
Node("n3") is at (2.0,0.0)
Node("n1") is at (-1.0,-4.0)
Node("n2") is at (2.0,-1.0)
=================================

Triangle: "B"
=================================
Edge("e1") connects nodes (n3, n1)
Edge("e2") connects nodes (n1, n2)
Edge("e3") connects nodes (n2, n3)
Node("n3") is at (1.0,0.0)
Node("n1") is at (1.0,4.0)
Node("n2") is at (1.0,1.0)
=================================
```
- Homework 5 is due on May 11. (No Extensions)
  Download the java source code and data files for the "blue pole" layout program. The contents of each file are as follows:
  - Vector.java . Defines (x,y) components for a two-dimensional vector.
  - Node.java . Extends vector and adds a name.
  - Edge.java . Defines an edge in the triangle. Edge contains two references to nodes, node1 and node2.
  - Pole.java . A pole is a node with extra color information.
  - PoleNetwork.java . This class contains methods to read a collection of poles from pole.txt and load them into an arraylist.
  - Triangle.java . Define a triangle as three edges and three nodes.
  - TriangleGUI.java . Graphical user interface for the "blue pole" application program.
  - TriangleMesh.java . This class contains methods to read a collection of triangles from triangle.txt. The mesh of triangles defines the shape and layout of buildings.
  - triangle.txt . Contains data for triangles in the triangle mesh.
  - pole.txt . Contains data for poles in the "blue pole" network.
  - TriangleGUI.html . This file contains html code for running the "blue pole" application program in the appletviewer. (The page will show up as a white web page with a broken applet. Use "view" "source" to see the html source, and then copy and paste the html code into your directory).
  To compile the program simply type:
```
    javac TriangleGUI.java
```
  The java compiler is pretty smart!. It will automatically identify the dependecies among files and compile all of the java source code. To run the program in the appletviewer, type:
```
    appletviewer TriangleGUI.html
```
  Question 5.1.
  In the prototype implementation, blue poles are defined by their name and (x,y) position. Extend the capabilities of Pole.java and the graphical user interface code so that poles are also defined by whether or not they contain a camera, and whether or not they are in service.
  To help you get started, the revised version of Pole.java might look like:
```
public class Pole extends Node {
   protected Color color;

   protected boolean bHasCamera;
   protected boolean bInService;

   ... details of Pole.java go here ...
```
  Variables "bHasCamera" and "bInService" will be either true or false. The extended pole.txt file might look like:
```
6
A   0.5 0.5  true   true
B   4.5 2.8  true   true
C   9.0 0.0  true  false
D   9.3 2.5 false   true
E  10.0 7.0  true   true
F  15.0 7.0  true   true
```
  Here, the fourth column of data indicates whether or not the pole contains a camera. The fifth columns of data indicates whether or not the pole is in service (notice that the pole beside A.V. Williams is, in fact, currently out of service!).
  Extend Pole.java to account for the additional functionality. You will need new methods for setCamera() and setService(), and will need to extend the constructors and toString(). Unless otherwise indicated, assume that "bHasCamera" and "bInService" are false. Extend main() to exercise all of the new parts of Pole.java.
  Then modify/extend PoleNetwork.java to read and process nodes in the extended file format shown above.
  Note. To help you out, my solution uses ideas from "GettinStarted.java" and the "Demo Strings" programs that are in class reader. The output to my solution for the Pole program is:
```
Pole("A") is at (1.0,2.0)
"Has camera" is false
"In service" is false
Pole("B") is at (3.0,8.0)
"Has camera" is true
"In service" is false
```
  The output to my solution for the PoleNetwork program is:
```
List of Poles                    
=================================
Pole("A") is at (0.5,0.5)
"Has camera" is true
"In service" is true
Pole("B") is at (4.5,2.8)
"Has camera" is true
"In service" is true
Pole("C") is at (9.0,0.0)
"Has camera" is true
"In service" is false
Pole("D") is at (9.3,2.5)
"Has camera" is false
"In service" is true
Pole("E") is at (10.0,7.0)
"Has camera" is true
"In service" is false
Pole("F") is at (15.0,7.0)
"Has camera" is true
"In service" is true
```
  What to Hand In.
  You should be able to complete this part of the assignment without using graphics at all. Hand in a copy of your program source code indicating all places where (just mark this up with a pen) where you have modified the code. Also, hand in a script file demonstrating the new functionality of Pole.java and PoleNetwork.java.
  Question 5.2.
  The prototype implementation allows a user to click on a point that lies inside a building, and the program will report the closest pole.
  Modify the program functionality so that:
  - The closest pole will be printed only if the point is outside. Otherwise, an error message should be displayed somewhere on the upper screen.
  - If a user clicks on a pole (i.e., the distance to the pole is less than a certain small number), then details of that pole (i.e., camera status, operational status) will be printed on the screen.
  Hand in a screendump of the "blue pole" application program that shows the modified program functionality.
  Screendumps (or screen shots) on Linux/Unix Systems
  On systems running the X Window System, the standard utility to dump an image of an X Window is xwd(1), The program xwd produces XWD X Window Dump image data. It can be invoked in the following way:
```
    xwd -root -out root.xwd
```
  xwd can also be used to dump a single window if provided with the -id option followed by the corresponding window id, for further info see man 1 xwd [1] (http://www.hmug.org/man/1/xwd.html). When run remotely, xwd is useful for taking screen shots of modal menus in action.
  For more info, see: Answers.com: Screenshot .
- Reading
  Read Chapter 19 of Austin/Chancogne. Focus on pages 554-565, 569-571 and Section 19.7 Handling AWT Events. The latter is very detailed, sorry. The architecture of the "blue pole" application is similar to Program 19.4, and has a class layout similar to that shown in Figures 19.18 and 19.19.
Week 16: May 9 and 11, 2005
- May 11. Last class. Overview of the course and hints for doing well on the final exam. Come to class with your questions.
- May 11. Handout solutions to homework 5.
Final Exam: May 19 (Thursday), 8.00am-10.00am. The final exam will be open book and open notes. There are three questions. Question 1 is on basic java concepts (30 pts). Question 2 is on java program development (30 pts). Question 3 is on java program development with graphical user interfaces (30 pts). Make sure that you bring Austin/Chancogne to the exam.

Developed in January 2005 by Mark Austin
Copyright © 2005, Department of Civil and Environmental Engineering, University of Maryland