$8\mathrm{.}48$ Program $12$: QR Code class

Instructor note:

Read about command$-$line arguments. We will show you in class how to use them.

To set command$-$line arguments in IntelliJ IDE. Modify the area called "Program arguments" $($outlined in the image with blue$).$

To set command$-$line arguments in Eclipse IDE:

Step $1$: Select the $$Run$$ tab from the top menu, then $->$Run Configurations...$.$

Step $2$: Specify the Program Arguments in the Arguments Tab.

Step $3$: Click on the Run button.

Introduction

This lab uses things you learned in your introductory programming class. Some of those things are:

constants

random numbers

overloaded methods

passing$/$returning arrays

filling and printing a one$-$dimensional array

filling and printing a two$-$dimensional array

Just for fun, we've included a GUI to visualize your QR code! Get it from the Program $12$ Assignment on Canvas.

Specifications

You will create a class QRCode that fills a grid with values that can be interpreted to visualize a QRCode image. $($This is not a true QRCode but a pattern similar to one.$)$

Required elements

QRCode class methods are instance methods.

Your program will contain a main method that creates an instance of QRCode and calls its methods such that the result output is a grid dim x dim with Finder values in the upper left, lower left, and upper right corners.

The dimension for the grid and the seed for the Random object must be passed in from the command line.

If two arguments are not passed in from the command line, your program should use constants defined below:

DEFAULT$\_$DIMENSION $30$

DEFAULT$\_$SEED $160$

Methods that return a value must pass unit tests that will not be made available for view, that is$,$ those methods should be thoroughly tested by you prior to submitting your program.

Only the print methods may have output to the console.

Class members must conform to the UML diagram below:

$================$ Class Name $================$

QRCode

$=============$ Private Variables $============$

$-$ grid : int$[][]$

$==============$ Public methods $==============$

$+$ createPattern$($dim : int, seed : int$)$ : int$[]$

$+$ setGrid$($dim : int, pattern : int$[])$ : void

$+$ getGrid$()$ : int$[][]$

$+$ setFinder$($xPos : int, yPos : int$)$ : void

$-$ fillSquare$($startX : int, startY : int, width : int, color: int$)$ : void $//$ possible helper method

$+$ addFinders$($dimension : int$)$ : void

$+$ print$()$ : void

$+$ print$($pattern : int$[])$ : void

$+$ print$($matrix : int$[][])$ : void

Method specifications

createPattern returns a new one$-$dimensional array the size of dim squared. The array should be filled with random $0\text{'}$s and $1\text{'}$s which are generated by a java.util.Random object constructed with the given seed.

setGrid takes in the dimension dim and instantiates a two$-$dimensional array size of dim by dim. The grid is then filled row by row from the pattern provided by the one$-$dimensional pattern passed in$.$

getGrid returns a representation of the grid member.

addFinders calls setFinder for each of the three finders $($upper left, upper right, lower left$)$ positions

setFinder calls fillSquare for each border$/$box which will overwrite the existing grid with the Finder pattern described here, placing a finder in each of the upper left, upper right, and lower left corners of the grid. If a grid is null, it returns null. The upper left corner of a Finder pattern is given by the parameters xPos and yPos which are the column and row, respectively, in the class member grid.

$-$ The output border is two pixels in width. All values are set to $1($WHITE in the GUI$).$

$-$ The next inner border is two pixels in width. All values are set to $0($BLACK in the GUI$).$

$-$ The next inner border is two pixels in width. All values are set to $2($WHITE in the GUI$).$

$-$ The innermost box is $3$x$3$ pixels. All values are set to $3($BLACK in the GUI$).$

fillSquare sets the specified color of a square given the dimension $($length$)$ and starting coordinates of the upper left corner of the square area. The border width is passed in but not used $($oops$!).$

print outputs the class member grid as a two$-$dimensional grid with no spaces between values in a row

print$($pattern$)$ outputs the one$-$dimensional pattern passed a a parameter as a two$-$dimensional grid with no spaces between values in a row

print$($matrix$)$ outputs the two$-$dimensional matrix passed as a parameter row by row with no spaces between values in a row

Testing

Things to test for are the correct number of command line arguments, a null pointer passed in if a pattern, grid, or matrix parameter structure has not actually been created yet, and the values of the Finder are as expected, among other things you can thing of$.$ Using the visualization testing program we provided will help verify the Finder values, plus you can pick out the pattern in the output too.

Here is an example of the code with the GUI: QR code with default values

Output with default values:

$111111111111111100111000100001111001001010010111111111111111$

$1111$