Formatting ASCII Charts With jOOQ

A very little known feature in jOOQ is the Formattable.formatChart() capability, which allows for formatting any jOOQ result as an ASCII chart. This can be useful for quick plotting of results in your console application.

Assuming you have a result set of this form (which is what you’re getting when you call result.format() or just result.toString())

+---+---+---+---+
|c  | v1| v2| v3|
+---+---+---+---+
|a  |  1|  2|  3|
|b  |  2|  1|  1|
|c  |  4|  0|  1|
+---+---+---+---+

This result can be produced by any query, or you can construct it without executing a query like this:

Field<String>  c  = field("c", VARCHAR);
Field<Integer> v1 = field("v1", INTEGER);
Field<Integer> v2 = field("v2", INTEGER);
Field<Integer> v3 = field("v3", INTEGER);

Result<Record4<String, Integer, Integer, Integer>> result = 
    create.newResult(c, v1, v2, v3); 
                      
result.add(create.newRecord(c, v1, v2, v3).values("a", 1, 2, 3));
result.add(create.newRecord(c, v1, v2, v3).values("b", 2, 1, 1));
result.add(create.newRecord(c, v1, v2, v3).values("c", 4, 0, 1));

Then, calling result.formatChart() will produce a nice ASCII chart like this, by default:

4.00|                                                  █████████████████████████
3.86|                                                  █████████████████████████
3.73|                                                  █████████████████████████
3.59|                                                  █████████████████████████
3.45|                                                  █████████████████████████
3.32|                                                  █████████████████████████
3.18|                                                  █████████████████████████
3.05|                                                  █████████████████████████
2.91|                                                  █████████████████████████
2.77|                                                  █████████████████████████
2.64|                                                  █████████████████████████
2.50|                                                  █████████████████████████
2.36|                                                  █████████████████████████
2.23|                                                  █████████████████████████
2.09|                                                  █████████████████████████
1.95|                         ██████████████████████████████████████████████████
1.82|                         ██████████████████████████████████████████████████
1.68|                         ██████████████████████████████████████████████████
1.55|                         ██████████████████████████████████████████████████
1.41|                         ██████████████████████████████████████████████████
1.27|                         ██████████████████████████████████████████████████
1.14|                         ██████████████████████████████████████████████████
1.00|███████████████████████████████████████████████████████████████████████████
----+---------------------------------------------------------------------------
    |            a                        b                        c            

It includes the first column as the category label on the x-axis, and the second column as the value to be plotted on the y-axis. You can tweak all sorts of configuration, including height and width:

result.formatChart(new ChartFormat().dimensions(6, 20));

To get this much smaller chart:

4.00|          █████
3.00|          █████
2.00|     ██████████
1.00|███████████████
----+---------------
    |  a    b    c  

To include the values of the other value columns in a stacked chart (which is the default) write:

result.formatChart(new ChartFormat()
    .dimensions(40, 8)
    .values(1, 2, 3)
);

Producing:

6.00|▒▒▒▒▒▒▒▒▒▒▒▒                       
5.00|▒▒▒▒▒▒▒▒▒▒▒▒            ▒▒▒▒▒▒▒▒▒▒▒
4.00|▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒███████████
3.00|▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓███████████
2.00|▓▓▓▓▓▓▓▓▓▓▓▓███████████████████████
1.00|███████████████████████████████████
----+-----------------------------------
    |     a           b          c      

If those default ASCII characters from the sweet old 90s MS-DOS and BBS times don’t align well with your font (e.g. as on this blog), you can switch them like this:

result.formatChart(new ChartFormat()
    .dimensions(40, 8)
    .values(1, 2, 3)
    .shades('@', 'o', '.')
);

And now you’re getting:

6.00|............                       
5.00|............            ...........
4.00|........................@@@@@@@@@@@
3.00|oooooooooooooooooooooooo@@@@@@@@@@@
2.00|oooooooooooo@@@@@@@@@@@@@@@@@@@@@@@
1.00|@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
----+-----------------------------------
    |     a           b          c      

Prefer displaying 100% charts? No problem

result.formatChart(new ChartFormat()
    .dimensions(40, 8)
    .values(1, 2, 3)
    .shades('@', 'o', '.')
    .display(Display.HUNDRED_PERCENT_STACKED)
);

And now, the result is:

100.00%|................................
 80.00%|......................@@@@@@@@@@
 60.00%|...........ooooooooooo@@@@@@@@@@
 40.00%|ooooooooooo@@@@@@@@@@@@@@@@@@@@@
 20.00%|ooooooooooo@@@@@@@@@@@@@@@@@@@@@
  0.00%|@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
-------+--------------------------------
       |     a          b         c     

Who needs MS Excel? No one, if you have jOOQ!