OOP-Test-2019

Rules

• You can access the Java reference and the Processing reference or the git reference if you need to look something up
• No use of notes or previously written code
• No collaboration or communication
• You can use your own computers and Visual Studio code or if on the lab computers you can use the shell scripts ./compile.sh and ./run.sh to compile and run your programs

Description

Resistors are electrical components that resist the flow of current through a circuit. The amount of resistance is measured in ohms. The resistance of a resistor can be evaluated by reading the colour bars. Here is a picture of one:

For the lab test today you will be making a program to visualise resistors with different resistances. This is what your finished sketch will look like:

There are two files in the data folder of the repository. The file colours.csv looks like this:

colour,r,g,b,value
black,0,0,0,0
brown,165,42,42,1
red,255,0,0,2
...
...

r,g,b are the RGB values of a colour and the value column repesents the value associated with the colour. Looking at the above extract from the file, you can see that the colour black represents the value 0 and the color red represents the value 2.

The second file is called resistors.csv and this file contains the resistors you will be visualising. Below is the contents of file:

618
27
195
93

Instructions

• Fork this repository to get the starter project. Clone the forked repo to your computer and check the upstream and origin remotes are set correctly
• Make a class called Colour that encapsulates the columns from a single row from the colours.csv file. Make the r,g,b and value fields public and the colour (String) field private. Make accessor methods for the colour field. Make a constructor that takes initial values and assigns them to the fields. Make an appropriate toString method.
• In UI.java:
  • Declare an ArrayList called colours that can hold instances of the Colour class
  • Write a method called loadColours that populates the ArrayList from the rows in colours.csv. You can use the Processing loadTable method to do this. To get full marks for this, you should write an appropriate overloaded constructor on the Colour object.
  • Write a method called printColours that prints the contents of the colours ArrayList to the console
  • Write a method public Color findColor(int value) in the class UI.java that returns the colour object associated with the value parameter.
• Make a class called Resistor that has the following public int fields:
  • value
  • ones
  • tens
  • hundreds
• Make a constructor that takes value as a parameter and assigns all fields. Here is some sample Java code that you can adapt that takes a value and calculates the ones, tens and hundreds. You will also find this code with some example usages in the file UI.java.

int hundreds = (value / 100);
int tens = (value - (hundreds * 100)) / 10;
int ones = value - ((hundreds * 100)  + (tens * 10));
print(hundreds + ",");
print(tens + ",");
println(ones);

In the above code, if value was 381, then hundreds would be 3, tens would be 8 and ones would be 1

• In UI.java, make an ArrayList called resistors to hold instances of the Resistor class. Populate this ArrayList from the rows in resistors.csv
• Write code in the draw method of UI.java that renders the resistors as per the screenshot above. To get full marks for this part, you should write an appropriate render method on the resistor class.

Marking Scheme

Description	Marks
Colour class, colours ArrayList population and printing	20 marks
Searching the colours ArrayList	10 marks
Resistor class, ArrayList population	20 marks
Drawing the resistors	40 marks
Use of git	10 marks

To get full marks for use of git you should make at least 5 commented commits on your repo at regular intervals or whenever you get something working.

Submit the URL to your git repository through this link