in regards to indecent exposure for code refactoring, what exactly would be a pliable definition? I keep looking online, but cannot find anything concrete or more than a word/two to define it? Also if you could provide me with a code example (in Java) where you have a case that has Indecent Exposure and a code example of a solution that would be terrific! If you could also give me some pros and cons of Indecent Exposure I would really appreciate.
I find this definition:
Do not expose any array publicly whose compile-time component type in not reifiable.
to be pretty specific; and it comes with code samples, too.
Related
I haven't used before a SAT solver, so I started to learn how to use SAT4J. Mostly, I am using its API, but I am finding hard to understand sometimes what some arguments (in classes or methods) mean or what their format/type is acceptable. For example:
public BinaryClause(IVecInt ps, ILits voc)
My question is if there are some usage examples, which can help me more in understanding the implemented features in SAT4j?
Thank you in advance!
You can find some usage examples of most features in the unit tests:
http://www.sat4j.org/maven234/org.ow2.sat4j.core/xref-test/index.html
BinaryClause class is not meant to be used by end users:
http://www.sat4j.org/maven234/org.ow2.sat4j.core/apidocs/index.html
We try to maintain user level doc up to date. The developer level may change over time, to may lack documentation.
Like many people, I've wanted to really learn smalltalk and TDD. For fun, I've been going through the excellent Tetris TDD tutorial at: https://github.com/orfjackal/tdd-tetris-tutorial/blob/tutorial/README.md
and converting the code to Smalltalk.
I've gotten to the third set of tests (https://github.com/orfjackal/tdd-tetris-tutorial/blob/tutorial/src/test/java/tetris/RotatingTetrominoesTest.java) which wants the objects representing the pieces to be immutable.
I'm not sure how to do this. Every attempt I make breaks the earlier tests. I did create a TetrisTetrominoe class as a subclass of TetrisPiece.
Using Pharo 3.0.
Thanks.
You have to take into account the dramatic difference between languages. Some time ago I've wrote a blog post with thoughts about immutability.
I think that if you want to follow test's for another language, you should try to find some for python or ruby, because they are also dynamic languages.
If you want to maintain immutability, I suggest you going the functional way, where each method that has intent to modify object creates a new one, with required properties. I doubt that this will satisfy java tests as java is not functional as much as it's not dynamic.
In smalltalk you would normally test for immutability by asking the mutators for their senders and then verifying that only the class method that creates the instances refers to it. So for instance:
testOnlyOneMutatorOfPrivateColor
self assert:
(SystemNavigation default allSendersOf: #privateColor:) size = 1
FxCop thought me (basically, from memory) that functions, classes and properties should be written in MajorCamelCase, while private variables should be in minorCamelCase.
I was talking about a reasonably popular project on IRC and quoted some code. One other guy, a fairly notorious troll who was also a half-op (gasp!) didn't seem to agree. Everything oughta be in the same casing, and he quite fervently favored MajorCamelCase, or even underscore_separation.
Ofcourse, he was just a troll so I reckoned I'd just keep doing it the way I already did. Before I learned the above guidelines, I hardly even had a coherent naming style.
He got me thinking, though -- does stuff like this really matter?
You need to make sure that your code is readable in the future. Please remember that you might want to pass the development of your application to someone else and this person will need to read and understand it. You could stop actively working on a project and return to it after a year - and be suprised that you have to read code carefully to understand how it works.
I believe it was Steve McConnell who said that specific naming style does not really matter (you could use anything you want as long as you are consistent) but this only applies when everyone working on the project agree with you.
In general it is better to adopt community-accepted coding styles where possible to facilitate code reuse and shorten learning curves.
If you don't care about long-term maintanability of your project (or consistency or readability) then no, casing (and coding conventions in general) don't really matter. Otherwise, they do matter. See this.
Your specific coding style doesn't matter (much), so long as it is consistent throughout the project.
This improves readability and understanding, as if an identifier is named in a particular way, the reader can (hopefully) be confident as to what that naming style implies.
As regards CamelCase v underscores, etc: again, it's down to your coding convention. One approach which uses both is to apply a prefix with underscore to indicate the module in which the function, or file-scope/global variable, is used, e.g. Config_Update(), Status_Get().
I'm running a refactoring code dojo for some coworkers who asked how refactoring and patterns go together, and I need a sample code base. Anyone know of a good starting point that isn't to horrible they can't make heads or tails of the code, but can rewrite their way to something useful?
I would actually suggesting refactoring some of your and your coworkers' code.
There are always places that an existing codebase can be refactored, and the familiarity with the existing code will help make it feel more like a useful thing and less like an exercise. Find something in your company's code to use as an example, if possible.
Here are some codes, both the original and the refactored version, so you can prepare your kata or simply compare the results once the refactoring is performed:
My books have both shorter examples and a longer, actually a book long example. Code is free to download.
VB Code Examples
C# Code Examples
A nice example from Refactoring Workbook
There are a lot of examples on the internet of simple games like Tic-Tac-Toe or Snake that have a lot of smells but are simple enough to start with refactoring.
The first chapter in Martin Fowler "Refactoring" is a good starting point to refactoring. I understood most of the concepts when one of my teachers at school used this example.
What is the general knowledge level of your coworkers?
Something basic as code duplication should be easy to wrap their heads around. Two pieces of (nearly) identical code that can be refactored into a reusable method, class, whatever. Using a (past) example from your own codebase would be good.
I would recommend you to develop a simple example project for a specific requirement.
Then you add one more requirement and make changes to the existing classes . You keep on doing this and show them how you are finding it difficult to make each change when the code is not designed properly. This will make them realize easily because, this is what those ppl will be doing in their day to day work. Make them realize that , if patterns and principles are not followed from beginning, how are they going to end up in mess at the end.
When they realize that,then you start from scratch or refactor the existing messed up code .Now add a requirement and make them realize that it is easy to make a change in the refactored code, so that you need to test only a few classes. One change would not affect others and so on.
You could use the computer ,keyboard and printer class as an example. Add requirements like, you will be wanting the computer to read from mouse , then one more requirement can be like your computer would want to save it in hard disk than printing. Finally your refactored code should be like, your computer class should depend on abstract input device class and output device class. And your keyboard class should inherit from Inputdevice class.
Clean Code: A Handbook of Agile Software Craftsmanship by Robert C. Martin considers refactoring.
I'm loving Refactoring Guru examples.
In there you can find design patterns examples too.
Refactoring is non-functional requirement when code perform correct functionality for which it is designed however difficult to debug, requires more effort to maintain and some performance bottleneck. Refactoring is to change to be easily maintainable, good readability and improve efficiency.
Thus we need to focus on criteria to make code more readable, easy to maintain.
Its obvious that having very large method/function might be difficult to understand.
Class depends on other hundreds of class make thing worst while debugging.
Code should be readable just like reading some workflow.
You can also use tools like sonar which can help you to identify critical criteria such as "Cyclomatic Complexity"
http://www.sonarsource.org/managing-cyclomatic-complexity-to-increase-maintainability/
You ask them to write code them self and check how tool does refactoring.
Apart from that, you can write code in eclipse and there is option available which does refactoring for you...
It's a bit dated (2003), but IBM has several refactoring examples (that work[ed?] in Eclipse) at http://www.ibm.com/developerworks/library/os-ecref/
In response to a previous question on how to achieve a certain effect with Swing, I was directed to JDesktopPane and JInternalFrame. Unfortunately, scala.swing doesn't seem to have any wrapper for either class, so I'm left with extending it.
What do I have to know and do to make minimally usable wrappers for these classes, to be used with and by scala.swing, and what would be the additional steps to make most of them?
Edit:
As suggested by someone, let me explain the effect I intend to achieve. My program controls (personal) lottery bets. So I have a number of different tickets, each of which can have a number of different bets, and varying validities.
The idea is displaying each of these tickets in a separate "space", and the JInternalFrames seems to be just what I want, and letting people create new tickets, load them from files, save them to files, and generally checking or editing the information in each.
Besides that, there needs to be a space to display the lottery results, and I intend to evolve the program to be able to control collective bets -- who contributed with how much, and how any winning should be split. I haven't considered the interface for that yet.
Please note that:
I can't "just use" the Java classes, and still take full advantage of Scala swing features. The answers in the previous question already tell me how to do what I want with the Java classes, and that is not what I'm asking here.
Reading the source code of existing scala.swing classes to learn how to do it is the work I'm trying to avoid with this question.
You might consider Scala's "implicit conversions" mechanism. You could do something like this:
implicit def enrichJInternalFrame(ji : JInternalFrame) =
new RichJInternalFrame(ji)
You now define a class RichJInternalFrame() which takes a JInternalFrame, and has whatever methods you'd like to extend JInternalFrame with, eg:
class RichJInternalFrame(wrapped : JInternalFrame) {
def showThis = {
wrapped.show()
}
}
This creates a new method showThis which just calls show on the JInternalFrame. You could now call this method on a JInternalFrame:
val jif = new JInternalFrame()
println(jif.showThis);
Scala will automatically convert jif into a RichJInternalFrame and let you call this method on it.
You can import all java libraries directly into your scala code.
Try the scala tutorial section: "interaction with Java".
Java in scala
You might be be able to use the scala.swing source as reference e.g. http://lampsvn.epfl.ch/svn-repos/scala/scala/trunk/src/swing/scala/swing/Button.scala
What sort of scala features are you trying to use with it? That might help in coming up with with an answer. I.e. - what is it you're trying to do with it, potentially in Java? Then we can try to come up with a nicer way to do it with Scala and/or create a wrapper for the classes which would make what you're trying to do even easier.
In JRuby, you could mix in one (or more) traits into JDesktopPane or JInternalFrame instead of extending them. This way you wouldn't have to wrap the classes but just use the existing objects. As far as I know, this is not possible with Scala traits.
Luckily, there is a solution, almost as flexible as Ruby's: lexically open classes. This blog article gives an excellent introduction, IMHO.