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• Should I care about Junit redundancy when using setUp() with @Before annotation?

  - by c_maker

  Even though developers have switched from junit 3.x to 4.x I still see the following 99% of the time: @Before public void setUp(){/*some setup code*/} @After public void tearDown(){/*some clean up code*/} Just to clarify my point... in Junit 4.x, when the runners are set up correctly, the framework will pick up the @Before and @After annotations no matter the method name. So why do developers keep using the same conventional junit 3.x names? Is there any harm keeping the old names while also using the annotations (other than it makes me feel like devs do not know how this really works and just in case, use the same name AND annotate as well)? Is there any harm in changing the names to something maybe more meaningful, like eachTestMethod() (which looks great with @Before since it reads 'before each test method') or initializeEachTestMethod()? What do you do and why? I know this is a tiny thing (and may probably be even unimportant to some), but it is always in the back of my mind when I write a test and see this. I want to either follow this pattern or not but I want to know why I am doing it and not just because 99% of my fellow developers do it as well.

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• Is there a common programming term for the problems of adding features to an already-featureful program?

  - by Jeremy Friesner

  I'm looking for a commonly used programming term to describe a software-engineering phenomenon, which (for lack of a better way to describe it) I'll illustrate first with a couple of examples-by-analogy: Scenario 1: We want to build/extend a subway system on the outskirts of a small town in Wyoming. There are the usual subway-problems to solve, of course (hiring the right construction company, choosing the best route, buying the subway cars), but other than that it's pretty straightforward to implement the system because there aren't a huge number of constraints to satisfy. Scenario 2: Same as above, except now we need to build/extend the subway system in downtown Los Angeles. Here we face all of the problems we did in case (1), but also additional problems -- most of the applicable space is already in use, and has a vocal constituency which will protest loudly if we inconvenience them by repurposing, redesigning, or otherwise modifying the infrastructure that they rely on. Because of this, extensions to the system happen either very slowly and expensively, or they don't happen at all. I sometimes see a similar pattern with software development -- adding a new feature to a small/simple program is straightforward, but as the program grows, adding further new features becomes more and more difficult, if only because it is difficult to integrate the new feature without adversely affecting any of the large number of existing use-cases or user-constituencies. (even with a robust, adaptable program design, you run into the problem of the user interface becoming so elaborate that the program becomes difficult to learn or use) Is there a term for this phenomenon?

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• Resource Acquisition is Initialization in C#

  - by codeWithoutFear

  Resource Acquisition Is Initialization (RAII) is a pattern I grew to love when working in C++.  It is perfectly suited for resource management such as matching all those pesky new's and delete's.  One of my goals was to limit the explicit deallocation statements I had to write.  Often these statements became victims of run-time control flow changes (i.e. exceptions, unhappy path) or development-time code refactoring. The beauty of RAII is realized by tying your resource creation (acquisition) to the construction (initialization) of a class instance.  Then bind the resource deallocation to the destruction of that instance.  That is well and good in a language with strong destructor semantics like C++, but languages like C# that run on garbage-collecting runtimes don't provide the same instance lifetime guarantees. Here is a class and sample that combines a few features of C# to provide an RAII-like solution: using System; namespace RAII { public class DisposableDelegate : IDisposable { private Action dispose; public DisposableDelegate(Action dispose) { if (dispose == null) { throw new ArgumentNullException("dispose"); } this.dispose = dispose; } public void Dispose() { if (this.dispose != null) { Action d = this.dispose; this.dispose = null; d(); } } } class Program { static void Main(string[] args) { Console.Out.WriteLine("Some resource allocated here."); using (new DisposableDelegate(() => Console.Out.WriteLine("Resource deallocated here."))) { Console.Out.WriteLine("Resource used here."); throw new InvalidOperationException("Test for resource leaks."); } } } } The output of this program is: Some resource allocated here. Resource used here. Unhandled Exception: System.InvalidOperationException: Test for resource leaks. at RAII.Program.Main(String[] args) in c:\Dev\RAII\RAII\Program.cs:line 40 Resource deallocated here. Code without fear! --Don

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• Random touchpad and keyboard freezes on new 10.10 installation

  - by ancaleth

  My touchpad and keyboard freeze up on my newly installed Ubuntu 10.10. I was using Ubuntu 10.4 via wubi before on this Laptop where this problem never occurred. (I did not migrate wubi or upgrade to 10.10, it's a fresh start. 64-bit on Dell Studio, plenty of RAM, plenty of free space on partition etc.) I can't say there is a pattern yet, once it happened during the download of packages with the Update Manager, once it was just using Firefox, no other program running. I was forced to shut down manually. In between these crashes the laptop was booted once, updates were installed etc., firefox was used and there weren't any problems. Both crashes should be in the attached kern.log and I noticed there were some error problems before the last crash (at the end, obviously). It seems the wireless was experiencing problems. This wasn't noticed on the user end, since the touchpad + keyboard were already frozen. kern.log: http://paste.ubuntu.com/552617/ How can the freezes be fixed?

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• WordPress mod_rewrite redirect specific folders

  - by Ps Cjef

  As a new user, I'm not allowed to post more than two hyperlinks here. So I have added a space after every http (ignore them and read as full URLs). System: Debian Etch, Apache 2.2 I have a WordPress instance with multiple blogs. I would like to redirect some of the folders based on the year and month, while leaving other folders go to the actual locations. Example: I have archives for a few years, like 2010, 2011 and 2012: http ://mydomain.com/wordpress/myblog/2010/02 http ://mydomain.com/wordpress/myblog/2011/01 http ://mydomain.com/wordpress/myblog/2012/01 I would like to redirect all 2010 and 2011 posts to another blog with the same folder structure: http ://mydomain.com/wordpress/myotherblog/2010/02 http ://mydomain.com/wordpress/myotherblog/2011/01 and so on. I would like to have 2012 and beyond to go to the actual site (http ://mydomain.com/wordpress/myblog/2012/01). I tried mod_rewrite with the following, one rule at a time to test redirection for just one year (and to expand later for other years), and none of them worked! * RewriteEngine is already on since there are some default WordPress rewrites. * RewriteBase is set to http://mydomain.com/wordpress/ . * I put my rule before all the other default WordPress rules are processed. Didn't work solution #1 RedirectMatch 301 /myblog/2010/(.*) /myotherblog/2010/$1 Didn't work solution #2 RewriteRule /myblog/2010/(.*) http ://mydomain.com/myotherblog/2010/$1 [R=301] Didn't work solution #3 RedirectPermanent /myblog/2010/(.*) http ://mydomain.com/myotherblog/2010/$1 I've also tried the above rules with and without a fully qualified URL for the new location. The rewrite log, with log level set to 9, did not provide any useful information. It shows that it looks at the pattern specified against the URL (as mentioned in the rule), but finally what happens is a passthrough to http ://mydomain.com/myblog/ for all URLs or a 500 Internal Server Error. Any ideas on where I could be going wrong or any alternative solutions?

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• design an extendible and pluggable business logic flow handler in php

  - by Broncha

  I am working on a project where I need to allow a pluggable way to inject business processes in the normal data flow. eg There is an ordering system. The standard flow of the application is A consumer orders an item. Pays for it and card is authorized. Admin captures the payment. Order is marked as complete and item is shipped. But this process may vary (extra steps in between) for different clients. Say a client would need to validate the location of the consumer before he is presented with a credit card form, OR his policies might require some other processes in between. I am thinking of using State Pattern for processing orders, saving the current state of the order in database, and initializing the state of order from the saved state. I would also need some mechanism, where a small plugin would be able to inject business specific states in the state machine. Am I thinking the right way? Are there already implemented patterns for this kind of situation? I am working with Codeigniter and basically this would mean for me, to redirect to proper controller according to the current state of the order. Like, if the state of the order is unconfirmed then redirect the user to details page and then change the state to pending. If some client would need to do some validation, then register an intermediate state between unconfirmed and pending Please suggest.

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• Making a class pseudo-immutable by setting a flag

  - by scott_fakename

  I have a java project that involves building some pretty complex objects. There are quite a lot (dozens) of different ones and some of them have a HUGE number of parameters. They also need to be immutable. So I was thinking the builder pattern would work, but it ends up require a lot of boilerplate. Another potential solution I thought of was to make a mutable class, but give it a "frozen" flag, a-la ruby. Here is a simple example: public class EqualRule extends Rule { private boolean frozen; private int target; public EqualRule() { frozen = false; } public void setTarget(int i) { if (frozen) throw new IllegalStateException( "Can't change frozen rule."); target = i; } public int getTarget() { return target; } public void freeze() { frozen = true; } @Override public boolean checkRule(int i) { return (target == i); } } and "Rule" is just an abstract class that has an abstract "checkRule" method. This cuts way down on the number of objects I need to write, while also giving me an object that becomes immutable for all intents and purposes. This kind of act like the object was its own Builder... But not quite. I'm not too excited, however, about having an immutable being disguised as a bean however. So I had two questions: 1. Before I go too far down this path, are there any huge problems that anyone sees right off the bat? For what it's worth, it is planned that this behavior will be well documented... 2. If so, is there a better solution? Thanks

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• JavaScript and callback nesting

  - by Jake King

  A lot of JavaScript libraries (notably jQuery) use chaining, which allows the reduction of this: var foo = $(".foo"); foo.stop(); foo.show(); foo.animate({ top: 0 }); to this: $(".foo").stop().show().animate({ top: 0 }); With proper formatting, I think this is quite a nice syntactic capability. However, I often see a pattern which I don't particularly like, but appears to be a necessary evil in non-blocking models. This is the ever-present nesting of callback functions: $(".foo").animate({ top: 0, }, { callback: function () { $.ajax({ url: 'ajax.php', }, { callback: function () { ... } }); } }); And it never ends. Even though I love the ease non-blocking models provide, I hate the odd nesting of function literals it forces upon the programmer. I'm interesting in writing a small JS library as an exercise, and I'd love to find a better way to do this, but I don't know how it could be done without feeling hacky. Are there any projects out there that have resolved this problem before? And if not, what are the alternatives to this ugly, meaningless code structure?

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• How can I design my classes for a calendar based on database events?

  - by Gianluca78

  I'm developing a web calendar in php (using Symfony2) inspired by iCal for a project of mine. At this moment, I have two classes: a class "Calendar" and a class "CalendarCell". Here you are the two classes properties and method declarations. class Calendar { private $month; private $monthName; private $year; private $calendarCellList = array(); private $translator; public function __construct($month, $year, $translator) {} public function getCalendarCells() {} public function getMonth() {} public function getMonthName() {} public function getNextMonth() {} public function getNextYear() {} public function getPreviousMonth() {} public function getPreviousYear() {} public function getYear() {} private function calculateDaysPreviousMonth() {} private function calculateNumericDayOfTheFirstDayOfTheWeek() {} private function isCurrentDay(\DateTime $dateTime) {} private function isDifferentMonth(\DateTime $dateTime) {} } class CalendarCell { private $day; private $month; private $dayNameAbbreviation; private $numericDayOfTheWeek; private $isCurrentDay; private $isDifferentMonth; private $translator; public function __construct(array $parameters) {} public function getDay() {} public function getMonth() {} public function getDayNameAbbreviation() {} public function isCurrentDay() {} public function isDifferentMonth() {} } Each calendar day can includes many events stored in a database. My question is: which is the best way to manage these events in my classes? I think to add a eventList property in CalendarCell and populate it with an array of CalendarEvent objects fetched by the database. This kind of solution doesn't allow other coders to reuse the classes without db (because I should inject at least a repository services also) just to create and visualize a calendar... so maybe it could be better to extend CalendarCell (for instance in CalendarCellEvent) and add the database features? I feel like I'm missing some crucial design pattern! Any suggestion will be very appreciated!

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• Why do Google search results include pages disallowed in robots.txt?

  - by Ilmari Karonen

  I have some pages on my site that I want to keep search engines away from, so I disallowed them in my robots.txt file like this: User-Agent: * Disallow: /email Yet I recently noticed that Google still sometimes returns links to those pages in their search results. Why does this happen, and how can I stop it? Background: Several years ago, I made a simple web site for a club a relative of mine was involved in. They wanted to have e-mail links on their pages, so, to try and keep those e-mail addresses from ending up on too many spam lists, instead of using direct mailto: links I made those links point to a simple redirector / address harvester trap script running on my own site. This script would return either a 301 redirect to the actual mailto: URL, or, if it detected a suspicious access pattern, a page containing lots of random fake e-mail addresses and links to more such pages. To keep legitimate search bots away from the trap, I set up the robots.txt rule shown above, disallowing the entire space of both legit redirector links and trap pages. Just recently, however, one of the people in the club searched Google for their own name and was quite surprised when one of the results on the first page was a link to the redirector script, with a title consisting of their e-mail address followed by my name. Of course, they immediately e-mailed me and wanted to know how to get their address out of Google's index. I was quite surprised too, since I had no idea that Google would index such URLs at all, seemingly in violation of my robots.txt rule. I did manage to submit a removal request to Google, and it seems to have worked, but I'd like to know why and how Google is circumventing my robots.txt like that and how to make sure that none of the disallowed pages will show up in their search results. Ps. I actually found out a possible explanation and solution, which I'll post below, while preparing this question, but I thought I'd ask it anyway in case someone else might have the same problem. Please do feel free to post your own answers. I'd also be interested in knowing if other search engines do this too, and whether the same solutions work for them also.

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• Where did I write that code ?

  - by Tarun Arora

  Every been in that situation when you desperately need to find that code you checked into TFS a few days back but just can’t remember what team project, what branch, what solution or what file you checked it into. Well you are not alone… Only if there was a way to efficiently search for files and text with in TFS. It is possible… You need to get your hands on Agent Ransack… This is a stand a lone tool that does not integrate with TFS but gives you the capability to search through text files effortlessly. Agent Ransack searches through files, text or otherwise, fast and efficiently. When searching the contents of files for code, or other text, Agent Ransack displays the text found so you can quickly browse the results without having to separately open each file! Agent Ransack is free for both Personal and Commercial use and can be Download from here.   Set the Look In directory of the Ransack search tool to your TFS Workspace and type the text you would like to scan for, you can limit the search by narrowing down the filter path or the name of the file. Found text is shown with highlighted keywords so you don't need to waste time opening each file looking for the right information.         The regular expression wizard helps you build regular expressions for complex pattern matching searches         You even have the option of searching by modified, created or last accessed date          Export your results to a file for importing into other apps or for sharing with others          Agent Ransack also provides search support for popular Office formats including Office 2007 and OpenOffice Next time you are looking for that illusive line of code whether it is a method declaration, function call, or algorithm that you checked into TFS, use Agent Ransack for a quick search.

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• How to control messages to the same port from different emitters?

  - by Alex In Paris

  Scene: A company has many factories X, each emits a message to the same receive port in a Biztalk server Y; if all messages are processed without much delay, each will trigger an outgoing message to another system Z. Problem: Sometimes a factory loses its connection for a half-day or more and, when the connection is reestablished, thousands of messages get emitted. Now, the messages still get processed well by Y (Biztalk can easily handle the load) but system Z can't handle the flood and may lock up and severely delay the processing of all other messages from the other X. What is the solution? Creating multiple receive locations that permits us to pause one X or another would lose us information if the factory isn't smart enough to know whether the message was received or not. What is the basic pattern to apply in Biztalk for this problem? Would some throttling parameters help to limit the flow from any one X? Or are their techniques on the end part of Y which I should use instead ? I would prefer this last one since I can be confident that the message box will remember any failures, which could then be resumed.

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• what should I read in Windows [closed]

  - by Umesha MS

  I think I am asking generic question. Being a developer in windows what should I read to improve my skills? Do I need to read concepts on need basis or do I need to read concepts well in advance? If I want to read the concepts in advance then what topics do I need to read. (Note : I am a Windows developer. I use c++ programming language, Win32/MFC frame work and I use Visual studio IDE.) Updated: To be more specific when a fresher comes to my team I will ask him to read the following things and I tell him that these are very important. 1)C++ : 1 The C++ Programming Language by Bjarne Stroustrup's 2 Thinking in C++ 2nd Edition by Bruce Eckel 2)Win32/MFC : 1 Programming Applications for Microsoft Windows by Jeffrey Richter 2 windows programming by charles petzold 3 Programming Windows with MFC –by Jeff Prosise For 2 years and above developer I ask them to read 1)Above concepts (C++ and Win32/MFC)are mandate 2)Design Pattern : 1)Gang Of Four. 2)Head first patter. 3)Design princples. But for above 6 years’ experience developer what are the concepts are important.

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• Best practice to collect information from child objects

  - by Markus

  I'm regularly seeing the following pattern: public abstract class BaseItem { BaseItem[] children; // ... public void DoSomethingWithStuff() { StuffCollection collection = new StuffCollection(); foreach(child c : children) c.AddRequiredStuff(collection); // do something with the collection ... } public abstract void AddRequiredStuff(StuffCollection collection); } public class ConcreteItem : BaseItem { // ... public override void AddRequiredStuff(StuffCollection collection) { Stuff stuff; // ... collection.Add(stuff); } } Where I would use something like this, for better information hiding: public abstract class BaseItem { BaseItem[] children; // ... public void DoSomethingWithStuff() { StuffCollection collection = new StuffCollection(); foreach(child c : children) collection.AddRange(c.RequiredStuff()); // do something with the collection ... } public abstract StuffCollection RequiredStuff(); } public class ConcreteItem : BaseItem { // ... public override StuffCollection RequiredStuff() { StuffCollection stuffCollection; Stuff stuff; // ... stuffCollection.Add(stuff); return stuffCollection; } } What are pros and cons of each solution? For me, giving the implementation access to parent's information is some how disconcerting. On the other hand, initializing a new list, just to collect the items is a useless overhead ... What is the better design? How would it change, if DoSomethingWithStuff wouldn't be part of BaseItem but a third class? PS: there might be missing semicolons, or typos; sorry for that! The above code is not meant to be executed, but just for illustration.

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• State Changes in a Component Based Architecture [closed]

  - by Maxem

  I'm currently working on a game and using the naive component based architecture thingie (Entities are a bag of components, entity.Update() calls Update on each updateable component), while the addition of new features is really simple, it makes a few things really difficult: a) multithreading / currency b) networking c) unit testing. Multithreading / Concurrency is difficult because I basically have to do poor mans concurrency (running the entity updates in separate threads while locking only stuff that crashes (like lists) and ignoring the staleness of read state (some states are already updated, others aren't)) Networking: There are no explicit state changes that I could efficiently push over the net. Unit testing: All updates may or may not conflict, so automated testing is at least awkward. I was thinking about these issues a bit and would like your input on these changes / idea: Switch from the naive cba to a cba with sub systems that work on lists of components Make all state changes explicit Combine 1 and 2 :p Example world update: statePostProcessing.Wait() // ensure that post processing has finished Apply(postProcessedState) state = new StateBag() Concurrently( () => LifeCycleSubSystem.Update(state), // populates the state bag () => MovementSubSystem.Update(state), // populates the state bag .... }) statePostProcessing = Future(() => PostProcess(state)) statePostProcessing.Start() // Tick is finished, the post processing happens in the background So basically the changes are (consistently) based on the data for the last tick; the post processing can a) generate network packages and b) fix conflicts / remove useless changes (example: entity has been destroyed - ignore movement etc.). EDIT: To clarify the granularity of the state changes: If I save these post processed state bags and apply them to an empty world, I see exactly what has happened in the game these state bags originated from - "Free" replay capability. EDIT2: I guess I should have used the term Event instead of State Change and point out that I kind of want to use the Event Sourcing pattern

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• How to choose between Tell don't Ask and Command Query Separation?

  - by Dakotah North

  The principle Tell Don't Ask says: you should endeavor to tell objects what you want them to do; do not ask them questions about their state, make a decision, and then tell them what to do. The problem is that, as the caller, you should not be making decisions based on the state of the called object that result in you then changing the state of the object. The logic you are implementing is probably the called object’s responsibility, not yours. For you to make decisions outside the object violates its encapsulation. A simple example of "Tell, don't Ask" is Widget w = ...; if (w.getParent() != null) { Panel parent = w.getParent(); parent.remove(w); } and the tell version is ... Widget w = ...; w.removeFromParent(); But what if I need to know the result from the removeFromParent method? My first reaction was just to change the removeFromParent to return a boolean denoting if the parent was removed or not. But then I came across Command Query Separation Pattern which says NOT to do this. It states that every method should either be a command that performs an action, or a query that returns data to the caller, but not both. In other words, asking a question should not change the answer. More formally, methods should return a value only if they are referentially transparent and hence possess no side effects. Are these two really at odds with each other and how do I choose between the two? Do I go with the Pragmatic Programmer or Bertrand Meyer on this?

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• When decomposing a large function, how can I avoid the complexity from the extra subfunctions?

  - by missingno

  Say I have a large function like the following: function do_lots_of_stuff(){ { //subpart 1 ... } ... { //subpart N ... } } a common pattern is to decompose it into subfunctions function do_lots_of_stuff(){ subpart_1(...) subpart_2(...) ... subpart_N(...) } I usually find that decomposition has two main advantages: The decomposed function becomes much smaller. This can help people read it without getting lost in the details. Parameters have to be explicitly passed to the underlying subfunctions, instead of being implicitly available by just being in scope. This can help readability and modularity in some situations. However, I also find that decomposition has some disadvantages: There are no guarantees that the subfunctions "belong" to do_lots_of_stuff so there is nothing stopping someone from accidentally calling them from a wrong place. A module's complexity grows quadratically with the number of functions we add to it. (There are more possible ways for things to call each other) Therefore: Are there useful convention or coding styles that help me balance the pros and cons of function decomposition or should I just use an editor with code folding and call it a day? EDIT: This problem also applies to functional code (although in a less pressing manner). For example, in a functional setting we would have the subparts be returning values that are combined in the end and the decomposition problem of having lots of subfunctions being able to use each other is still present. We can't always assume that the problem domain will be able to be modeled on just some small simple types with just a few highly orthogonal functions. There will always be complicated algorithms or long lists of business rules that we still want to correctly be able to deal with. function do_lots_of_stuff(){ p1 = subpart_1() p2 = subpart_2() pN = subpart_N() return assembleStuff(p1, p2, ..., pN) }

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• How to populate a private container for unit test?

  - by Sardathrion

  I have a class that defines a private (well, __container to be exact since it is python) container. I am using the information within said container as part of the logic of what the class does and have the ability to add/delete the elements of said container. For unit tests, I need to populate this container with some data. That date depends on the test done and thus putting it all in setUp() would be impractical and bloated -- plus it could add unwanted side effects. Since the data is private, I can only add things via the public interface of the object. This run codes that need not be run during a unit test and in some case is just a copy and paste from another test. Currently, I am mocking the whole container but somehow it does not feel that elegant a solution. Due to Python mocking frame work (mock), this requires the container to be public -- so I can use patch.dict(). I would rather keep that data private. What pattern can one use to still populate the containers without excising the public method so I have data to test with? Is there a way to do this with mock' patch.dict() that I missed?

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• Are super methods in JavaScript limited to functional inheritance, as per Crockford's book?

  - by kindohm

  In Douglas Crockford's "JavaScript: The Good Parts", he walks through three types of inheritance: classical, prototypal, and functional. In the part on functional inheritance he writes: "The functional pattern also gives us a way to deal with super methods." He then goes on to implement a method named "superior" on all Objects. However, in the way he uses the superior method, it just looks like he is copying the method on the super object for later use: // crockford's code: var coolcat = function(spec) { var that = cat(spec), super_get_name = that.superior('get_name'); that.get_name = function (n) { return 'like ' + super_get_name() + ' baby'; }; return that; }; The original get_name method is copied to super_get_name. I don't get what's so special about functional inheritance that makes this possible. Can't you do this with classical or prototypal inheritance? What's the difference between the code above and the code below: var CoolCat = function(name) { this.name = name; } CoolCat.prototype = new Cat(); CoolCat.prototype.super_get_name = CoolCat.prototype.get_name; CoolCat.prototype.get_name = function (n) { return 'like ' + this.super_get_name() + ' baby'; }; Doesn't this second example provide access to "super methods" too?

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• How to divide work to a network of computers?

  - by Morpork

  Imagine a scenario as follows: Lets say you have a central computer which generates a lot of data. This data must go through some processing, which unfortunately takes longer than to generate. In order for the processing to catch up with real time, we plug in more slave computers. Further, we must take into account the possibility of slaves dropping out of the network mid-job as well as additional slaves being added. The central computer should ensure that all jobs are finished to its satisfaction, and that jobs dropped by a slave are retasked to another. The main question is: What approach should I use to achieve this? But perhaps the following would help me arrive at an answer: Is there a name or design pattern to what I am trying to do? What domain of knowledge do I need to achieve the goal of getting these computers to talk to each other? (eg. will a database, which I have some knowledge of, be enough or will this involve sockets, which I have yet to have knowledge of?) Are there any examples of such a system? The main question is a bit general so it would be good to have a starting point/reference point. Note I am assuming constraints of c++ and windows so solutions pointing in that direction would be appreciated.

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• How to avoid the GameManager god object?

  - by lorancou

  I just read an answer to a question about structuring game code. It made me wonder about the ubiquitous GameManager class, and how it often becomes an issue in a production environment. Let me describe this. First, there's prototyping. Nobody cares about writing great code, we just try to get something running to see if the gameplay adds up. Then there's a greenlight, and in an effort to clean things up, somebody writes a GameManager. Probably to hold a bunch of GameStates, maybe to store a few GameObjects, nothing big, really. A cute, little, manager. In the peaceful realm of pre-production, the game is shaping up nicely. Coders have proper nights of sleep and plenty of ideas to architecture the thing with Great Design Patterns. Then production starts and soon, of course, there is crunch time. Balanced diet is long gone, the bug tracker is cracking with issues, people are stressed and the game has to be released yesterday. At that point, usually, the GameManager is a real big mess (to stay polite). The reason for that is simple. After all, when writing a game, well... all the source code is actually here to manage the game. It's easy to just add this little extra feature or bugfix in the GameManager, where everything else is already stored anyway. When time becomes an issue, no way to write a separate class, or to split this giant manager into sub-managers. Of course this is a classical anti-pattern: the god object. It's a bad thing, a pain to merge, a pain to maintain, a pain to understand, a pain to transform. What would you suggest to prevent this from happening?

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• MVC and delegation

  - by timjver

  I am a beginning iOS programmer and use the Model-View-Controller model as a design pattern: my model doesn't know anything about my view (in order to make it compatible with any view), my view doesn't know anything about my model so they interact via my controller. A very usual way for a view to interact with the controller is through delegation: when the user interacts with the app, my view will notify my controller, which can call some methods of my model and update my view, if necessary. However, would it make sense to also make my controller the delegate of my model? I'm not convinced this is the way to go. It could be handy for my model to notify my controller of some process being finished, for example, or to ask for extra input of the user if it doesn't have enough information to complete the task. The downside of this, though, is that my controller would be the delegate for both my controller and my model, so there wouldn't be really a proper way to notify my model of changes in my view, and vice versa. (correct me if I'm wrong.) Conclusion: I don't really think it's a good idea to to have my controller to be the delegate of my model, but just being the delegate of my view would be fine. Is this the way most MVC models handle? Or is there a way to have the controller be the delegate of both the controller and the model, with proper communication between them? Like I said, I'm a beginner, so I want to do such stuff the right way immediately, rather than spending loads of hours on models that won't work anyway. :)

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• How to quickly search through a very large list of strings / records on a database

  - by Giorgio

  I have the following problem: I have a database containing more than 2 million records. Each record has a string field X and I want to display a list of records for which field X contains a certain string. Each record is about 500 bytes in size. To make it more concrete: in the GUI of my application I have a text field where I can enter a string. Above the text field I have a table displaying the (first N, e.g. 100) records that match the string in the text field. When I type or delete one character in the text field, the table content must be updated on the fly. I wonder if there is an efficient way of doing this using appropriate index structures and / or caching. As explained above, I only want to display the first N items that match the query. Therefore, for N small enough, it should not be a big issue loading the matching items from the database. Besides, caching items in main memory can make retrieval faster. I think the main problem is how to find the matching items quickly, given the pattern string. Can I rely on some DBMS facilities, or do I have to build some in-memory index myself? Any ideas? EDIT I have run a first experiment. I have split the records into different text files (at most 200 records per file) and put the files in different directories (I used the content of one data field to determine the directory tree). I end up with about 50000 files in about 40000 directories. I have then run Lucene to index the files. Searching for a string with the Lucene demo program is pretty fast. Splitting and indexing took a few minutes: this is totally acceptable for me because it is a static data set that I want to query. The next step is to integrate Lucene in the main program and use the hits returned by Lucene to load the relevant records into main memory.

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• Architecture for dashboard showing aggregated stats [on hold]

  - by soulnafein

  I'd like to know what are common architectural pattern for the following problem. Web application A has information on sales, users, responsiveness score, etc. Some of this information are computationally intensive and or have a complex business logic (e.g. responsiveness score). I'm building a separate application (B) for internal admin tasks that modifies data in web application A and report on data from web application A. For writing I'm planning to use a restful api. E.g. create a new entity, update entity, etc. In application B I'd like to show some graphs and other aggregate data for the previous 12 months. I'm planning to store the aggregate data for each month in redis. Some data should update more often, e.g every 10 minutes. I can think of 3 ways of doing this. A scheduled task in app B that connects to an api of app A that provides some aggregated data. Then app B stores it in Redis and use that to visualise pages. Cons: it makes complex calculation within a web request, requires lot's of work e.g. api server and client, storing, etc., pros: business logic still lives in app A. A scheduled task in app A that aggregates data in an non-web process and stores it directly in Redis to be accessed by app B. A scheduled task in app A that aggregates data in a non-web process and uses an api in app B to save it. I'd like to know if there is a well known architectural solution to this type of problems and if not what are other pros/cons for the solution I've suggested?

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• How should I structure the implementation of turn-based board game rules?

  - by Setzer22

  I'm trying to create a turn-based strategy game on a tilemap. I'm using design by component so far, but I can't find a nice way to fit components into the part I want to ask. I'm struggling with the "game rules" logic. That is, the code that displays the menu, allows the player to select units, and command them, then tells the unit game objects what to do given the player input. The best way I could thing of handling this was using a big state machine, so everything that could be done in a "turn" is handled by this state machine, and the update code of this state machine does different things depending on the state. However, this approach leads to a large amount of code (anything not model-related) going into a big class. Of course I can subdivide this big class into more classes, but it doesn't feel modular and upgradable enough. I'd like to know of better systems to handle this in order to be able to upgrade the game with new rules without having a monstruous if/else chain (or switch / case, for that matter). Any ideas? What specific design pattern other than MVC should I be using?

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