Implement analyzer for cars-assemble concept exercise

[chiarazarrella]

Closes #103

In the design.md of the exercise there is such rule:

• informative: If the solution has if/else-if statements in the productionRatePerHour method, inform the student that creating a helper method to calculate the succes rate might make their code easier to understand.

However, I reused an existing comment: method_too_long, which I think it fits with the request. The only difference is that such comment is of type ACTIONABLE, meanwhile in the design.md file it is requested to be INFORMATIVE.

ToDo:

• Add website-copy comment
• Check comments #2380

[IsaacG]

+cc the @exercism/java maintainers

[kahgoh]

This method seems to check if the number 221 appears anywhere, but the comment in the design.md seems to suggest that it should check if the number appears more than once in the code:

If the solution is repeatedly hard-coding the value 221, inform the student that they could store this value in a field to make the code easier to maintain.

An alternate solution may to set it to a final variable (within a method), especially if it isn't used anywhere else. If the value appears only once, I think that could be fine.

[kahgoh]

Something here seems strange here. You get a list of IfStmts, start iterating, but return true / false depending on whether the first if statement in the list is has an else block? What about the other if statements?

Even if you really did mean to check just the first if statement, I think the not-using-helper-method test would fail if productionRatePerHour used multiple returns like this community solution:

public class CarsAssemble {

    public double productionRatePerHour(double speed) {
        double baseProductionRate = 221;

        if (speed >= 1 && speed <= 4) {
            return speed * baseProductionRate;
        } else if (speed >= 5 && speed <= 8) {
            return speed * baseProductionRate * 0.9;
        } else if (speed == 9) {
            return speed * baseProductionRate * 0.8;
        }
        return speed * baseProductionRate * 0.77;
    }

    public int workingItemsPerMinute(int speed) {
       return (int) productionRatePerHour(speed)/60;

       
    }
}

[kahgoh]

I'm concerned that reusing the MethodTooLong could be confusing for the students. There's nothing in the comment that hints students should move the if statement. I think its really hard for the students to tell that they should move it a helper method because it only tells them to make the method smaller, but we actually them to specifically move the if statement into a separate method. The actionable level may be too high for this comment too.