Liutauras Vilda

First, pie slices to those who haven't got yet!!!

Some interesting points floating around, which in turn already allowed me to see some deficiencies with my current design. I need to absorb/experiment with each of these first.

But even now, I already can say a big thanks for your time and constructive criticism - I'll get back to each of you (salvin, Piet, Sresh), either late night today or other day once manage to spend some time on it.

6 days ago

In case somebody reads, one of my colleague here, Stephan, raised some concerns (behind the hood, within GitHub platform) regarding the topology, where I mixed up two different contexts Location and Direction into one - Location, and as a result represented directions where to move in order to find neighbours by reusing Location class (and that is bad), which actually represents an absolute path within a world map. So separated these lately and now there are Location and Direction (appear as an inner enum as it is needed just there for the moment).

Another point we discussed that I have an enum Cell which implements (/-ed actually) Mutable interface. And there he had a point. Enum is an immutable from Java's stand point, and to implement Mutable interface was a bit odd, even though the ideas underneath didn't clash much as simply two different domains interfered Java's (immutable enum) and automaton game (where cell mutates). As a result I renamed Mutable idea within the domain entirely, so it became:

Mutable -> Regenerable Mutable.mutate() -> Regenerable.regenerate() MutationRules -> RegenerationRules

And these make much more sense now. Thanks to him.

However, we still got an argument whether to represent Cell as an enum is a good idea. Maybe to have Cell as a regular class with an inner enum State ALIVE, ETC... would be better. I must say I had implemented that 2 days ago - well, more experiments to come.

It is very interesting little project to work on.

1 week ago

salvin francis wrote:I ran that program and it just printed a huge log of dots and zeros !!!
Even a simple JFrame with a single textarea would be great.

Yet again, first of all, thanks for reviewing it.

Yeah. Agree, it isn't user friendly and much interactive yet. But I have created for myself an enhancement item, so at some point will get it done.

However, at this stage my main goal was to come up with a design so it would be simple to understand, easy enough extend and very importantly to test. Tried to keep separate pieces responsible as much as their need to be responsible for, so changing something I wouldn't need to rewrite tests from scratch and similar. Interesting, but initially that was exactly my experience. Started with semi TDD, thought came up with a fairly nice approach, however, trapped to a situation, that I was not able to test everything without exposing objects internals as for instance Location class was relying on World's internal data structure to count alive neighbours around, and I did want to have minimum getters, minimum mutation... etc. So most of the time such figuring out design, but I'll have time for GUI, just my designer's skills aren't anywhere great.

salvin francis wrote:I am glad to see that your glider "wraps-around" the world.

Yep, since all action happens on an infinite grid, I was looking for the way to put this concept in place.

Thanks for comments.

salvin francis wrote:minor suggestions: Maybe World.SIZE could have an access modifier (probably public) ?

Nah

Stephan some time ago suggested, and once again re-read Effective Java by Joshua Bloch, so basically I give visibility as much as it is needed and no more. On that point of view, I'd prefer that even interfaces would provide an ability to implement package-private methods, as sometimes (and I faced this situation too), I exposed method (meaning had to make public) without real need of that, i.e. Cell.mutate() is public, while perfectly could work with package-private visibility.

1 week ago

Jeanne Boyarsky wrote:In World, the indentation of this code misleads about what it does. Since the two forEach() statements are aligned, they imply that they are operating on the same stream.

First - thankful for a review and comments.

Agreed. Indentation was misleading. With streams kind of can get messy when always aligning by the dot ".". I simply now just let IDE to format for me based on by default pre-configured its rules.

Jeanne Boyarsky wrote:More importantly, calling map.put() in a forEach isn't good practice. Is there any reason you can't use a collector which would dispense with the inner forEach() entirely.

That's a good one! I was so concentrated on design, so got less than optimum at other points. Initially I simply had 2 habitual loops, so later decided to replace with forEach, hence got horrible blocks. Just refactored to use collectors you suggested in empty(); nextGeneration(); methods, indeed much better as it hides internals how data structure gets populated. However, a bit struggled until remembered how to do it with specific Map's implementation.

Jeanne Boyarsky wrote:I'm not a fan of the default method in Mutate. It feels like a hack since it isn't used for legacy code.

Well. I was researching about default before attempted to use it. To my disappointment, since Java moving towards modernising herself, I don't understand why default is so implied to be used only for legacy code. It is such a nice feature to have in my opinion (makes even slimmer gap between interface vs abstract class) and it fitted perfectly to my idea. Upon hypothetical requirements change mutable(s), i.e. Monster just need to implement that interface without providing any extras; and define their mutation rules. I'm not up (convinced yet) for removing it and implementing this method in the very same way in each and every concrete Mutable implementation.

Thanks for the comments once again!

1 week ago

Java 11 now available for download

Junilu Lacar wrote:If I had a collection of Book objects, would bookList.toArray(Book[]::new) be easier to read than bookList.toArray(new Book[0])?

With no doubts. new Book[0] is confusing as hell to me, because it gives an impression that it will create a 0 length array, and since we know arrays can't expand, it gives a feeling

while Book[]::new suggests me that it will create an array of the needed size whatever that size might be, which in fact I don't need to know. That's how my brains interpret that.

1 week ago

Java in General

Hello Ranchers,

For a long time I was fascinated about this project, but never attempted to implement it myself. That's changed.
So decided to create a personal construction site and work at it to practice and experiment with various design decisions implementing this cellular automaton.

For the past 3-4 days I wrote and re-wrote.. this project countless number of times (small portion of commits history recorded).
The version I have currently is something I think I could try to justify why I have it like that, and to what angle it has flexibility to offer so I chose to implement it that way.

However, do extra pairs of eyes see some illogical design decisions, or have tips what to think about how this could be improved further to avoid some potential limitations I could face when some hypothetical requirements change?

Don't get fooled by the width of the project (only very few source files), but it really taught me many lessons already, and I believe it will again.

From the very first versions I came up with, this recent version I think got shorter twice, I think it has more flexible design, it was way easier to test and achieve good enough test coverage. I'm currently at a stage when I need some subtle tips to move on further refinements (or.. fixes).

Please find project implementation at my GitHub area. For those who don't know the mentioned project, please read the description on Wikipedia.

Thanks.

1 week ago

Software craftsmanship events

Software craftsmanship events worth knowing, attending...

(sorted by the 'when' in an ascending order)

Name	When	Where	About
Hackathon	~Mid of October (lasts 1-2 day(s))	Physical attendance. Facilitated all around the world.	A design sprint-like event in which computer programmers and others involved in software development, including graphic designers, interface designers, project managers, and others, often including subject-matter-experts, collaborate intensively on software projects.
Global Day of Coderetreat	~Mid of November (lasts 1 day)	Physical attendance. Facilitated all around the world.	Intensive practice event, focusing on the fundamentals of software development and design.
Advent of Code	~1st Dec - ~25th Dec (25 days long)	Online attendance.	Fun series of small programming puzzles for a variety of skill levels.

1 week ago

Wiki

Reading in a 16-digit credit card number

And modulus really help you to extract digits.

Think how dividing and using modulus operator you can extract individual digits. Brute force way to understand is to get calculator and play a bit (with some pretty predictable numbers to use for division, modulus) and see what you get.

1 week ago

Reading in a 16-digit credit card number

jon ninpoja wrote:1234567890 % 10000
...
7890 it gave me the last four digits

but why is that?

jon, it is really easy to understand, you just need some primitive (might even dumb) example. Ignore what these mathematicians mumble around (just kidding), nobody understands them apart themselves

Imagine you have 10 apples. So what is the remainder 10 % 3...

So you simply do:
10 - 3 = 7
7 - 3 = 4
4 - 3 = 1
1 - 3 = alert, insufficient fonds. You have only 1 left.

So that 1 is the remainder. How it is implemented internally - not our business (probably differently than I described), but that certainly should help to understand what the remainder is.

Is any clearer now how you got 7890? (1234567890 % 10000)
1234567890 - 10000 = ...
... - 10000 = ...
7890 - 10000 = alert, insuf... Déjà vu

1 week ago

RockPaperScissors

Carey Brown wrote:I haven't looked at all the code, but this is a mistake:
'|' is bit-wise OR and '||' is logical OR. Unless you are doing bit manipulation use logical OR
'&' is bit-wise AND and '&&' is logical AND. Use the logical AND.

Well, in more cases than not, it wouldn't cause code to misbehave, so that's not really a mistake, but more of unappropriate use in my opinion (not in all scenarios, though).

M. Gumblert wrote:hishand == "p"

This one is a mistake.

1 week ago

LinkedList add() method not working

Micheal Bush wrote:Can you solve it??

I'm sure he can, anyway, that is your task for this very exercise. That is a part of learning process, I'm sure you do understand that. If you'd do as he suggested, probably you'd have it solved by now.

If you have been told an exact answer or provided with complete solution - you wouldn't have learned anything. The sooner you'll understand that, the easier is going to be in a future. You need to try to crack down the problems yourself, hints are fine though, we all sometimes need hints.

1 week ago

Is this a problem with composition?

Maurizio Gasparro wrote:Junilu, your explaination about naming the fields or variables and the DRY principle it's veru useful for me because I'm a novice, so I need to know these things.

Not only novices need to be told these type of principles. It is ongoing process. Experienced and well experienced programmers also need to be trained in the same way, even though they know them. Similarly as sportsmen. All of them know their stuff, how to compete, even win, but they do have trainers who help them to refine their techniques so they can aim to be champions, and most importantly - need to be able to keep that level, and presumably grow - that is what coaches do, and this is in fact who Junilu is. So expect to see, hear and learn these type of principles constantly during your career as a programmer.

1 week ago

Trying to make a grading program loop to start from the beginning

Passed OCAJP8 91%

Congratulations on passing and passing with a great score.

Thanks for offering help... and welcome to the Ranch

1 week ago

Certification Results

I'm a bit disappointed that @OP is satisfied with such his approach solving this exercise.

I was studying myself and I know that having everything so chaotic leads nowhere. Better code organization is expected right from the 1st day of Introduction to Programming course. Meaning no prior experience is needed, but better code organization *is* expected. And that is not because somebody requires like that, that is because *that way* is much easier to solve problems.

1. All the comments you have aren't useful. And in some places - misleading. An example:

Scanner input = new Scanner(System.in); System.out.println("Enter Your Name"); //displays name name = input.nextLine();

So what we see here. My guess is that OP's comments referring to the preceding lines. However, if you look closely, this comment is nonsense. I'll leave for OP to figure out what is wrong there.

2. Very first line says Averages5.java, yet the class declaration says it is Averages7. That shows how such comments go out of date in a blink of an eye. So better not to have such comments which say nothing and usually say wrong.

3. Snippet below:
@OP You don't need all these && operators. Think how you could simplify this code. i.e.:

4. Did you learn methods yet? Anyway, since you already using them, i.e.: main(), I'd suggest start organizing your program into methods, where each method does one thing and one thing only. i.e.:

Every little detail is important. You need to take control of your code and don't let the chaotic code ruin your project.

1 week ago