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  • Testcase runner for parametrized testcases

    - by Razer
    Let me explain my situation. I'm planning a kind of test case runner for doing testcases on external devices, which are microcontroller based. Lets consider the devices: Device 1 Device 2 There exist a lot of test cases which can be run with one of the devices above. For example: Testcase 1 Testcase 2 The main reason that all the testcases can be run with any device is, that the testcases validates some standard and this software should be extensible for future devices. The testcases itself must be runnable with changing parameters. For example Testcase 1 does some Timing Verification the testcase needs as input parameter the datarate: 4800, 9600, 19200. Now hoping you understand the situation, let me explain my design questions. For implementing the test cases I thought about an Attribute based approach, like nunit does it. The more complicated problem is, how to define the parametrized testcases? Like this: Device 1: Testcase 1: datarate: 4800, 9600, 19200 Testcase 2: supply: 1, 2, 3 Device 2: Testcase 1: datarate: 9600, 19200, 38400 Testcase 2: supply: 3, 4, 5 How would you design such a framework? I've done a similar desin in python where I had for every device a XML containing the testcase definitions like: <Testcase="Testcase 1" datarate=4800/> <Testcase="Testcase 1" datarate=9600/> <Testcase="Testcase 1" datarate=19200/>

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  • Designing a plug-in system

    - by madflame991
    I'm working on a Java project and I would like to add a plug-in system. More precisely, I would like to let the user design his own module, pack it into a jar, leave it in a "plugins/" subfolder of my application and be done with it. I've managed to get a child classloader to instantiate objects of classes located in external jars, but now I'm facing a design dilemma: Say Joe makes a plug-in and he packs it in joeplugin.jar. I would really like Joe to have a class named "instantiation.Factory" and I would also like everyone to have this class with this exact location and name. (This factory class obviously implements a interface that I provide and through it I get what I want from the plug-in.) If Joe wouldn't be restricted in this way I would have to look into his entire jar for some class that implements my factory interface and I don't want to imagine how complicated things get. So my question is: should I enforce a strict naming convention for this single class? I have no idea how plug-in systems work.

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  • Procedural content (settlement) generation

    - by instancedName
    I have, lets say, something like a homework or assignment to do. Roughly said I need to write an algorithm (pseudo code is not necessary, just in depth description) of procedure that would generate settlements, environment and a people to populate it with, as part of some larger world generation procedure. The genre of game is not specified, it could be any genre (rpg, strategy, colony simulation etc.) where interacting with large and extensive world is central to the game. Procedure should be called once per settlement. At the time of calling, world generation procedure makes geography, culture and history input available. Output should be map of the village and it's immediate area, and various potential additional information like myths, history, demographic facts etc. Bonus would be quest ant similar stuff, but that not really my focus at the moment. I will leave quality of the output for later when I actually dig little deeper into this topic. I am free to change parameters as long as I have strong explanation for doing so. Setting of the game is undetermined so I am free to use anything that I like the most. Ok, so my actual question is: Can anyone who has some experience in this field of game design recommend me some good literature, or point me in the direction where I should look/reed/study? I'm somewhat experienced game programmer, but I've never been into game design till now so any help will be great. I want to do this assignment as good as I can. As for deadline, it's not strictly set, but lets say I don't want it to take longer then few weeks, one month at worst case.

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  • First Project a big one, How much should we charge?

    - by confuzzled
    Two of my cousins and I started a freelance computer repair/web design business just to make some money on the side during college, and received our first major web design project about three weeks ago. Now we've created websites before, but it was mostly for family businesses and have never really charged money, and most of the websites have been static, and don't really require a CMS. This project, however, was a big one (for us anyways). We created a news site that had several categories, we created the banners, we created a classifieds page (not a web app just something static that they control). Several links, a few graphical assets, CSS drop down menu, RSS feed from a different news site, weather, all the normal stuff you would find on a regular news site. On top of that we put in all the usual Joomla stuff (search, Jcomments, Jslide pictures, JCE, etc.). Then we uploaded the first 10 articles they gave us, and we are going to train them how to use Joomla. Now, at first we decided for 700 dollars. I assumed they just wanted a simple blog like website where they can upload articles. But then we had a meeting, and they asked for a lot more. Note: we did not hard code the template from scratch, but customized the gantry framework to fit their needs. We did code quite a bit however. I estimate that we put in about 50-60 hours in total. I'm wondering if 700 dollars is a bit low, this price is definitely not set in stone. Please keep in mind that this is our first project, and we are newbies, please be kind. Thank You!

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  • What do you wish language designers paid attention to?

    - by Berin Loritsch
    The purpose of this question is not to assemble a laundry list of programming language features that you can't live without, or wish was in your main language of choice. The purpose of this question is to bring to light corners of languge design most language designers might not think about. So, instead of thinking about language feature X, think a little more philisophically. One of my biases, and perhaps it might be controversial, is that the softer side of engineering--the whys and what fors--are many times more important than the more concrete side. For example, Ruby was designed with a stated goal of improving developer happiness. While your opinions may be mixed on whether it delivered or not, the fact that was a goal means that some of the choices in language design were influenced by that philosophy. Please do not post: Syntax flame wars (I could care less whether you use whitespace [Python], keywords [Ruby], or curly braces [Java, C/C++, et. al.] to denote program blocks). That's just an implementation detail. "Any language that doesn't have feature X doesn't deserve to exist" type comments. There is at least one reason for all programming languages to exist--good or bad. Please do post: Philisophical ideas that language designers seem to miss. Technical concepts that seem to be poorly implemented more often than not. Please do provide an example of the pain it causes and if you have any ideas of how you would prefer it to function. Things you wish were in the platform's common library but seldom are. One the same token, things that usually are in a common library that you wish were not. Conceptual features such as built in test/assertion/contract/error handling support that you wish all programming languages would implement properly--and define properly. My hope is that this will be a fun and stimulating topic.

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  • Making money from a custom built interpreter?

    - by annoying_squid
    I have been making considerable progress lately on building an interpreter. I am building it from NASM assembly code (for the core engine) and C (cl.exe the Microsoft compiler for the parser). I really don't have a lot of time but I have a lot of good ideas on how to build this so it appeals to a certain niche market. I'd love to finish this but I need to face reality here ... unless I can make some good monetary return on my investment, there is not a lot of time for me to invest. So I ask the following questions to anyone out there, especially those who have experience in monetizing their programs: 1) How easy is it for a programmer to make good money from one design? (I know this is vague but it will be interesting to hear from those who have experience or know of others' experiences). 2) What are the biggest obstacles to making money from a programming design? 3) For the parser, I am using the Microsoft compiler (no IDE) I got from visual express, so will this be an issue? Will I have to pay royalties or a license fee? 4) As far as I know NASM is a 2-clause BSD licensed application. So this should allow me to use NASM for commericial development unless I am missing something? It's good to know these things before launching into the meat and potatoes of the project.

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  • Is there a canonical source supporting "all-surrogates"?

    - by user61852
    Background The "all-PK-must-be-surrogates" approach is not present in Codd's Relational Model or any SQL Standard (ANSI, ISO or other). Canonical books seems to elude this restrictions too. Oracle's own data dictionary scheme uses natural keys in some tables and surrogate keys in other tables. I mention this because these people must know a thing or two about RDBMS design. PPDM (Professional Petroleum Data Management Association) recommend the same canonical books do: Use surrogate keys as primary keys when: There are no natural or business keys Natural or business keys are bad ( change often ) The value of natural or business key is not known at the time of inserting record Multicolumn natural keys ( usually several FK ) exceed three columns, which makes joins too verbose. Also I have not found canonical source that says natural keys need to be immutable. All I find is that they need to be very estable, i.e need to be changed only in very rare ocassions, if ever. I mention PPDM because these people must know a thing or two about RDBMS design too. The origins of the "all-surrogates" approach seems to come from recommendations from some ORM frameworks. It's true that the approach allows for rapid database modeling by not having to do much business analysis, but at the expense of maintainability and readability of the SQL code. Much prevision is made for something that may or may not happen in the future ( the natural PK changed so we will have to use the RDBMS cascade update funtionality ) at the expense of day-to-day task like having to join more tables in every query and having to write code for importing data between databases, an otherwise very strightfoward procedure (due to the need to avoid PK colisions and having to create stage/equivalence tables beforehand ). Other argument is that indexes based on integers are faster, but that has to be supported with benchmarks. Obviously, long, varying varchars are not good for PK. But indexes based on short, fix-length varchar are almost as fast as integers. The questions - Is there any canonical source that supports the "all-PK-must-be-surrogates" approach ? - Has Codd's relational model been superceded by a newer relational model ?

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  • Web Services and code lists

    - by 0x0me
    Our team heavily discuss the issues how to handle code list in a web service definition. The design goal is to describe a provider API to query a system using various values. Some of them are catalogs resp. code lists. A catalog or code list is a set of key value pairs. There are different systems (at least 3) maintaining possibly different code lists. Each system should implement the provider API, whereas each system might have different code list for the same business entity eg. think of colors. One system know [(1,'red'),(2,'green')] and another one knows [(1,'lightgreen'),(2,'darkgreen'),(3,'red')] etc. The access to the different provider API implementations will be encapsulated by a query service, but there is already one candidate which might use at least one provider API directly. The current options to design the API discussed are: use an abstract code list in the interface definition: the web service interface defines a well known set of code list which are expected to be used for querying and returning data. Each API provider implementation has to mapped the request and response values from those abstract codelist to the system specific one. let the query component handle the code list: the encapsulating query service knows the code list set of each provider API implementation and takes care of mapping the input and output to the system specific code lists of the queried system. do not use code lists in the query definition at all: Just query code lists by a plain string and let the provider API implementation figure out the right value. This might lead to a loose of information and possibly many false positives, due to the fact that the input string could not be canonical mapped to a code list value (eg. green - lightgreen or green - darkgreen or both) What are your experiences resp. solutions to such a problem? Could you give any recommendation?

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  • Looking for a better Factory pattern (Java)

    - by Sam Goldberg
    After doing a rough sketch of a high level object model, I am doing iterative TDD, and letting the other objects emerge as a refactoring of the code (as it increases in complexity). (That whole approach may be a discussion/argument for another day.) In any case, I am at the point where I am looking to refactor code blocks currently in an if-else blocks into separate objects. This is because there is another another value combination which creates new set of logical sub-branches. To be more specific, this is a trading system feature, where buy orders have different behavior than sell orders. Responses to the orders have a numeric indicator field which describes some event that occurred (e.g. fill, cancel). The combination of this numeric indicator field plus whether it is a buy or sell, require different processing buy the code. Creating a family of objects to separate the code for the unique handling each of the combinations of the 2 fields seems like a good choice at this point. The way I would normally do this, is to create some Factory object which when called with the 2 relevant parameters (indicator, buysell), would return the correct subclass of the object. Some times I do this pattern with a map, which allows to look up a live instance (or constructor to use via reflection), and sometimes I just hard code the cases in the Factory class. So - for some reason this feels like not good design (e.g. one object which knows all the subclasses of an interface or parent object), and a bit clumsy. Is there a better pattern for solving this kind of problem? And if this factory method approach makes sense, can anyone suggest a nicer design?

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  • ASP.NET Webforms developers and web designers: how to interact?

    - by just_name
    I'm an ASP.NET Webforms developer, and I face some problems when I deal with designers. Designers always complain about the asp.net server controls. They'd rather just have an html file and create css files along with the required images to go with those. Sometimes, if the design phase is done in advance, I get html files with related css files, but then we face many problems integrating the design with the aspx files (sever controls an telerik controls ... etc). What I want to ask about is: How do I overcome these problems? The designers prefer php- and mvc developers because of the problems with .net server controls. I need to know how to interact with the designers in the correct way. Are there any tools or applications to provide the designers with the rendered (html page) of the .aspx pages? By that I mean the page in runtime rather than the aspx in Visual Studio. They do use Web Expression but they want the rendered page in html as well.

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  • Object desing problem for simple school application

    - by Aragornx
    I want to create simple school application that provides grades,notes,presence,etc. for students,teachers and parents. I'm trying to design objects for this problem and I'm little bit confused - because I'm not very experienced in class designing. Some of my present objects are : class PersonalData() { private String name; private String surename; private Calendar dateOfBirth; [...] } class Person { private PersonalData personalData; } class User extends Person { private String login; private char[] password; } class Student extends Person { private ArrayList<Counselor> counselors = new ArrayList<>(); } class Counselor extends Person { private ArrayList<Student> children = new ArrayList<>(); } class Teacher extends Person { private ArrayList<ChoolClass> schoolClasses = new ArrayList<>(); private ArrayList<Subject> subjects = new ArrayList<>(); } This is of course a general idea. But I'm sure it's not the best way. For example I want that one person could be a Teacher and also a Parent(Counselor) and present approach makes me to have two Person objects. I want that user after successful logging in get all roles that it has (Student or Teacher or (Teacher & Parent) ). I think I should make and use some interfaces but I'm not sure how to do this right. Maybe like this: interface Role { } interface TeacherRole implements Role { void addGrade( Student student, Grade grade, [...] ); } class Teacher implements TeacherRole { private Person person; [...] } class User extends Person{ ArrayList<Role> roles = new ArrayList<>(); } Please if anyone could help me to make this right or maybe just point me to some literature/article that covers practical objects design.

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  • How to correctly write an installation or setup document

    - by UmNyobe
    I just joined a small start-up as a software engineer after graduation. The start-up is 4 year old, and I am working with the CEO and the COO, even if there are some people abroad. Basically they both used to do almost everything. I am currently on some kind of training phase. I have at my disposition architecture, setup and installation internal documentation. Architecture documentation is like a bible and should contain complete information. The rest are used to give directions in different processes. The issue is that these documents are more or less dated, as they just didn't have the time to change them. I will be in charge of training the next hires, and updating these documents is part of my training. In some there is a lot of hard-coded information like: Install this_module_which_still_exists cd this_dir_name_changed cp this_file_name_changed other_dir_name_changed ./config_script.sh ./execute_script.sh The issues i have faced : Either the module installation is completely different (for instance now there is an rpm, or a different OS) Either names changed, and i need to switch old names by new names Description of the purpose of the current step missing. Information about a whole topic is missing Fortunately these guys are around and I get all the information I want and all the explanations I need. I want to bring a design to the next documents so in the future people don't feel like they are completely rewriting a document each time they are updating it. Do you have suggestions? If there is a lightweight design methodology available online you can point me to it's nice too. One thing I will do for sure is set up a versioning repository for the documents alone. There is already one for the source code so I don't know why internal documents deserve a different treatment.

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  • Help with Abstract Factory Pattern

    - by brazc0re
    I need help with a abstract factory pattern design. This question is a continuation of: Design help with parallel process I am really confused where I should be initializing all of the settings for each type of medium (ex: RS232, TCP/IP, etc). Attached is the drawing on how I am setting up the pattern: As shown, when a medium is created, each medium imposes a ICreateMedium interface. I would assume that the Create() method also create the proper object, such as SerialPort serialPort = new SerialPort("COM1", baud); however, TCPIPMedium would have an issue with the interface because it wouldn't need to initialize a serial port object. I know I am doing something majorly wrong here. I just can't figure it out and have been stuck for a while. What I also get confused on show the interface IMedium will get access to the communication object once it is created so it can write out the appropriate byte[] packet. Any guidance would be greatly appreciated. My main goal is to have the Communicator class spit a packet out without caring which type of medium is active.

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  • .net developers and web designers: how to interact?

    - by just_name
    I'm an asp.net developer, and I face some problems when I deal with designers. The designer always complains about the asp.net server controls. They rather just have an html file and create css files along with the required images to go with those. Sometimes if the design phase is done in advance I get html files with related css files, but then we face many problems integrating the design with the aspx files (sever controls an telerik controls ... etc). What I want to ask about is: How to overcome these problems? The designers prefer php- and mvc developers because of the problems with .net server controls. I need to know how to interact with the designers in a correct way. Are there any tools or applications to provide the designers with the rendered (html page) of the .aspx pages? By that I mean the page in runtime rather than the aspx in visual studio. They do use Web Expression but they want the rendered page in html as well.

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  • Replace conditional with polymorphism refactoring or similar?

    - by Anders Svensson
    Hi, I have tried to ask a variant of this question before. I got some helpful answers, but still nothing that felt quite right to me. It seems to me this shouldn't really be that hard a nut to crack, but I'm not able to find an elegant simple solution. (Here's my previous post, but please try to look at the problem stated here as procedural code first so as not to be influenced by the earlier explanation which seemed to lead to very complicated solutions: http://stackoverflow.com/questions/2772858/design-pattern-for-cost-calculator-app ) Basically, the problem is to create a calculator for hours needed for projects that can contain a number of services. In this case "writing" and "analysis". The hours are calculated differently for the different services: writing is calculated by multiplying a "per product" hour rate with the number of products, and the more products are included in the project, the lower the hour rate is, but the total number of hours is accumulated progressively (i.e. for a medium-sized project you take both the small range pricing and then add the medium range pricing up to the number of actual products). Whereas for analysis it's much simpler, it is just a bulk rate for each size range. How would you be able to refactor this into an elegant and preferably simple object-oriented version (please note that I would never write it like this in a purely procedural manner, this is just to show the problem in another way succinctly). I have been thinking in terms of factory, strategy and decorator patterns, but can't get any to work well. (I read Head First Design Patterns a while back, and both the decorator and factory patterns described have some similarities to this problem, but I have trouble seeing them as good solutions as stated there. The decorator example seems very complicated for just adding condiments, but maybe it could work better here, I don't know. And the factory pattern example with the pizza factory...well it just seems to create such a ridiculous explosion of classes, at least in their example. I have found good use for factory patterns before, but I can't see how I could use it here without getting a really complicated set of classes) The main goal would be to only have to change in one place (loose coupling etc) if I were to add a new parameter (say another size, like XSMALL, and/or another service, like "Administration"). Here's the procedural code example: public class Conditional { private int _numberOfManuals; private string _serviceType; private const int SMALL = 2; private const int MEDIUM = 8; public int GetHours() { if (_numberOfManuals <= SMALL) { if (_serviceType == "writing") return 30 * _numberOfManuals; if (_serviceType == "analysis") return 10; } else if (_numberOfManuals <= MEDIUM) { if (_serviceType == "writing") return (SMALL * 30) + (20 * _numberOfManuals - SMALL); if (_serviceType == "analysis") return 20; } else //i.e. LARGE { if (_serviceType == "writing") return (SMALL * 30) + (20 * (MEDIUM - SMALL)) + (10 * _numberOfManuals - MEDIUM); if (_serviceType == "analysis") return 30; } return 0; //Just a default fallback for this contrived example } } All replies are appreciated! I hope someone has a really elegant solution to this problem that I actually thought from the beginning would be really simple... Regards, Anders

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  • Is it worthwhile to implement observer pattern in PHP?

    - by Extrakun
    I have been meaning to make use of design pattern in PHP, such as the observer pattern, but that I have to recreate the observers' relationship each time the page is loaded pains me. As references are saved as a new concrete objects in session, there is no way to preserve relationships between subscribers and their observers unless you use a GUID or some other properties to form a lookup, and store that property instead. With the cost of recreating the relationships each time a page is loaded, is it worthwhile to use design patterns such as observers in PHP, compared to having a clean design? Any real-world experience to share?

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  • Personal project in Java

    - by Chuck
    My first project in java is going to be a program (eventually I have to create a GUI interface but for now CLI would do) to keep track of my books (something similar to what libraries have only a simpler). I need to be able to insert, update, remove, show all books, update, search(by name or author or date). For the design I was thinking one main class Library which will have all of the above as methods that connect to the db and retrieve the data. Is this approach ok? I realize it's simple but it's my first real project and I would appreciate a little feedback. Also, is it too soon to consider reading up on design patterns and database design ?

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  • User Control as container

    - by Luca
    I'm designing a simple expander control. I've derived from UserControl, drawn inner controls, built, run; all ok. Since an inner Control is a Panel, I'd like to use it as container at design time. Indeed I've used the attributes: [Designer(typeof(ExpanderControlDesigner))] [Designer("System.Windows.Forms.Design.ParentControlDesigner, System.Design", typeof(IDesigner))] Great I say. But it isn't... The result is that I can use it as container at design time but: The added controls go back the inner controls already embedded in the user control Even if I push to top a control added at design time, at runtime it is back again on controls embedded to the user control I cannot restrict the container area at design time into a Panel area What am I missing? Here is the code for completeness... why this snippet of code is not working? [Designer(typeof(ExpanderControlDesigner))] [Designer("System.Windows.Forms.Design.ParentControlDesigner, System.Design", typeof(IDesigner))] public partial class ExpanderControl : UserControl { public ExpanderControl() { InitializeComponent(); .... [System.Security.Permissions.PermissionSet(System.Security.Permissions.SecurityAction.Demand, Name = "FullTrust")] internal class ExpanderControlDesigner : ControlDesigner { private ExpanderControl MyControl; public override void Initialize(IComponent component) { base.Initialize(component); MyControl = (ExpanderControl)component; // Hook up events ISelectionService s = (ISelectionService)GetService(typeof(ISelectionService)); IComponentChangeService c = (IComponentChangeService)GetService(typeof(IComponentChangeService)); s.SelectionChanged += new EventHandler(OnSelectionChanged); c.ComponentRemoving += new ComponentEventHandler(OnComponentRemoving); } private void OnSelectionChanged(object sender, System.EventArgs e) { } private void OnComponentRemoving(object sender, ComponentEventArgs e) { } protected override void Dispose(bool disposing) { ISelectionService s = (ISelectionService)GetService(typeof(ISelectionService)); IComponentChangeService c = (IComponentChangeService)GetService(typeof(IComponentChangeService)); // Unhook events s.SelectionChanged -= new EventHandler(OnSelectionChanged); c.ComponentRemoving -= new ComponentEventHandler(OnComponentRemoving); base.Dispose(disposing); } public override System.ComponentModel.Design.DesignerVerbCollection Verbs { get { DesignerVerbCollection v = new DesignerVerbCollection(); v.Add(new DesignerVerb("&asd", new EventHandler(null))); return v; } } } I've found many resources (Interaction, designed, limited area), but nothing was usefull for being operative...

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  • Plagued by multithreaded bugs

    - by koncurrency
    On my new team that I manage, the majority of our code is platform, TCP socket, and http networking code. All C++. Most of it originated from other developers that have left the team. The current developers on the team are very smart, but mostly junior in terms of experience. Our biggest problem: multi-threaded concurrency bugs. Most of our class libraries are written to be asynchronous by use of some thread pool classes. Methods on the class libraries often enqueue long running taks onto the thread pool from one thread and then the callback methods of that class get invoked on a different thread. As a result, we have a lot of edge case bugs involving incorrect threading assumptions. This results in subtle bugs that go beyond just having critical sections and locks to guard against concurrency issues. What makes these problems even harder is that the attempts to fix are often incorrect. Some mistakes I've observed the team attempting (or within the legacy code itself) includes something like the following: Common mistake #1 - Fixing concurrency issue by just put a lock around the shared data, but forgetting about what happens when methods don't get called in an expected order. Here's a very simple example: void Foo::OnHttpRequestComplete(statuscode status) { m_pBar->DoSomethingImportant(status); } void Foo::Shutdown() { m_pBar->Cleanup(); delete m_pBar; m_pBar=nullptr; } So now we have a bug in which Shutdown could get called while OnHttpNetworkRequestComplete is occuring on. A tester finds the bug, captures the crash dump, and assigns the bug to a developer. He in turn fixes the bug like this. void Foo::OnHttpRequestComplete(statuscode status) { AutoLock lock(m_cs); m_pBar->DoSomethingImportant(status); } void Foo::Shutdown() { AutoLock lock(m_cs); m_pBar->Cleanup(); delete m_pBar; m_pBar=nullptr; } The above fix looks good until you realize there's an even more subtle edge case. What happens if Shutdown gets called before OnHttpRequestComplete gets called back? The real world examples my team has are even more complex, and the edge cases are even harder to spot during the code review process. Common Mistake #2 - fixing deadlock issues by blindly exiting the lock, wait for the other thread to finish, then re-enter the lock - but without handling the case that the object just got updated by the other thread! Common Mistake #3 - Even though the objects are reference counted, the shutdown sequence "releases" it's pointer. But forgets to wait for the thread that is still running to release it's instance. As such, components are shutdown cleanly, then spurious or late callbacks are invoked on an object in an state not expecting any more calls. There are other edge cases, but the bottom line is this: Multithreaded programming is just plain hard, even for smart people. As I catch these mistakes, I spend time discussing the errors with each developer on developing a more appropriate fix. But I suspect they are often confused on how to solve each issue because of the enormous amount of legacy code that the "right" fix will involve touching. We're going to be shipping soon, and I'm sure the patches we're applying will hold for the upcoming release. Afterwards, we're going to have some time to improve the code base and refactor where needed. We won't have time to just re-write everything. And the majority of the code isn't all that bad. But I'm looking to refactor code such that threading issues can be avoided altogether. One approach I am considering is this. For each significant platform feature, have a dedicated single thread where all events and network callbacks get marshalled onto. Similar to COM apartment threading in Windows with use of a message loop. Long blocking operations could still get dispatched to a work pool thread, but the completion callback is invoked on on the component's thread. Components could possibly even share the same thread. Then all the class libraries running inside the thread can be written under the assumption of a single threaded world. Before I go down that path, I am also very interested if there are other standard techniques or design patterns for dealing with multithreaded issues. And I have to emphasize - something beyond a book that describes the basics of mutexes and semaphores. What do you think? I am also interested in any other approaches to take towards a refactoring process. Including any of the following: Literature or papers on design patterns around threads. Something beyond an introduction to mutexes and semaphores. We don't need massive parallelism either, just ways to design an object model so as to handle asynchronous events from other threads correctly. Ways to diagram the threading of various components, so that it will be easy to study and evolve solutions for. (That is, a UML equivalent for discussing threads across objects and classes) Educating your development team on the issues with multithreaded code. What would you do?

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  • How to Correct & Improve the Design of this Code?

    - by DaveDev
    HI Guys, I've been working on a little experiement to see if I could create a helper method to serialize any of my types to any type of HTML tag I specify. I'm getting a NullReferenceException when _writer = _viewContext.Writer; is called in protected virtual void Dispose(bool disposing) {/*...*/} I think I'm at a point where it almost works (I've gotten other implementations to work) and I was wondering if somebody could point out what I'm doing wrong? Also, I'd be interested in hearing suggestions on how I could improve the design? So basically, I have this code that will generate a Select box with a number of options: // the idea is I can use one method to create any complete tag of any type // and put whatever I want in the content area <% using (Html.GenerateTag<SelectTag>(Model, new { href = Url.Action("ActionName") })) { %> <%foreach (var fund in Model.Funds) {%> <% using (Html.GenerateTag<OptionTag>(fund)) { %> <%= fund.Name %> <% } %> <% } %> <% } %> This Html.GenerateTag helper is defined as: public static MMTag GenerateTag<T>(this HtmlHelper htmlHelper, object elementData, object attributes) where T : MMTag { return (T)Activator.CreateInstance(typeof(T), htmlHelper.ViewContext, elementData, attributes); } Depending on the type of T it'll create one of the types defined below, public class HtmlTypeBase : MMTag { public HtmlTypeBase() { } public HtmlTypeBase(ViewContext viewContext, params object[] elementData) { base._viewContext = viewContext; base.MergeDataToTag(viewContext, elementData); } } public class SelectTag : HtmlTypeBase { public SelectTag(ViewContext viewContext, params object[] elementData) { base._tag = new TagBuilder("select"); //base.MergeDataToTag(viewContext, elementData); } } public class OptionTag : HtmlTypeBase { public OptionTag(ViewContext viewContext, params object[] elementData) { base._tag = new TagBuilder("option"); //base.MergeDataToTag(viewContext, _elementData); } } public class AnchorTag : HtmlTypeBase { public AnchorTag(ViewContext viewContext, params object[] elementData) { base._tag = new TagBuilder("a"); //base.MergeDataToTag(viewContext, elementData); } } all of these types (anchor, select, option) inherit from HtmlTypeBase, which is intended to perform base.MergeDataToTag(viewContext, elementData);. This doesn't happen though. It works if I uncomment the MergeDataToTag methods in the derived classes, but I don't want to repeat that same code for every derived class I create. This is the definition for MMTag: public class MMTag : IDisposable { internal bool _disposed; internal ViewContext _viewContext; internal TextWriter _writer; internal TagBuilder _tag; internal object[] _elementData; public MMTag() {} public MMTag(ViewContext viewContext, params object[] elementData) { } public void Dispose() { Dispose(true /* disposing */); GC.SuppressFinalize(this); } protected virtual void Dispose(bool disposing) { if (!_disposed) { _disposed = true; _writer = _viewContext.Writer; _writer.Write(_tag.ToString(TagRenderMode.EndTag)); } } protected void MergeDataToTag(ViewContext viewContext, object[] elementData) { Type elementDataType = elementData[0].GetType(); foreach (PropertyInfo prop in elementDataType.GetProperties()) { if (prop.PropertyType.IsPrimitive || prop.PropertyType == typeof(Decimal) || prop.PropertyType == typeof(String)) { object propValue = prop.GetValue(elementData[0], null); string stringValue = propValue != null ? propValue.ToString() : String.Empty; _tag.Attributes.Add(prop.Name, stringValue); } } var dic = new Dictionary<string, object>(StringComparer.OrdinalIgnoreCase); var attributes = elementData[1]; if (attributes != null) { foreach (PropertyDescriptor descriptor in TypeDescriptor.GetProperties(attributes)) { object value = descriptor.GetValue(attributes); dic.Add(descriptor.Name, value); } } _tag.MergeAttributes<string, object>(dic); _viewContext = viewContext; _viewContext.Writer.Write(_tag.ToString(TagRenderMode.StartTag)); } } Thanks Dave

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  • 15 Stylish Navigation Menus For Inspiration

    - by Jyoti
    A site’s navigation menu is one of the most prominent things that users see when they first visit. There are many ways to design a navigation menu  and since almost all websites have some form of navigation designers have to push their creative limits to build one that’s remarkable and outstanding. In this article, you’ll [...]

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  • Windows Azure End to End Examples

    - by BuckWoody
    I’m fascinated by the way people learn. I’m told there are several methods people use to understand new information, from reading to watching, from experiencing to exploring. Personally, I use multiple methods of learning when I encounter a new topic, usually starting with reading a bit about the concepts. I quickly want to put those into practice, however, especially in the technical realm. I immediately look for examples where I can start trying out the concepts. But I often want a “real” example – not just something that represents the concept, but something that is real-world, showing some feature I could actually use. And it’s no different with the Windows Azure platform – I like finding things I can do now, and actually use. So when I started learning Windows Azure, I of course began with the Windows Azure Training Kit – which has lots of examples and labs, presentations and so on. But from there, I wanted more examples I could learn from, and eventually teach others with. I was asked if I would write a few of those up, so here are the ones I use. CodePlex CodePlex is Microsoft’s version of an “Open Source” repository. Anyone can start a project, add code, documentation and more to it and make it available to the world, free of charge, using various licenses as they wish. Microsoft also uses this location for most of the examples we publish, and sample databases for SQL Server. If you search in CodePlex for “Azure”, you’ll come back with a list of projects that folks have posted, including those of us at Microsoft. The source code and documentation are there, so you can learn using actual examples of code that will do what you need. There’s everything from a simple table query to a full project that is sort of a “Corporate Dropbox” that uses Windows Azure Storage. The advantage is that this code is immediately usable. It’s searchable, and you can often find a complete solution to meet your needs. The disadvantage is that the code is pretty specific – it may not cover a huge project like you’re looking for. Also, depending on the author(s), you might not find the documentation level you want. Link: http://azureexamples.codeplex.com/site/search?query=Azure&ac=8    Tailspin Microsoft Patterns and Practices is a group here that does an amazing job at sharing standard ways of doing IT – from operations to coding. If you’re not familiar with this resource, make sure you read up on it. Long before I joined Microsoft I used their work in my daily job – saved a ton of time. It has resources not only for Windows Azure but other Microsoft software as well. The Patterns and Practices group also publishes full books – you can buy these, but many are also online for free. There’s an end-to-end example for Windows Azure using a company called “Tailspin”, and the work covers not only the code but the design of the full solution. If you really want to understand the thought that goes into a Platform-as-a-Service solution, this is an excellent resource. The advantages are that this is a book, it’s complete, and it includes a discussion of design decisions. The disadvantage is that it’s a little over a year old – and in “Cloud” years that’s a lot. So many things have changed, improved, and have been added that you need to treat this as a resource, but not the only one. Still, highly recommended. Link: http://msdn.microsoft.com/en-us/library/ff728592.aspx Azure Stock Trader Sometimes you need a mix of a CodePlex-style application, and a little more detail on how it was put together. And it would be great if you could actually play with the completed application, to see how it really functions on the actual platform. That’s the Azure Stock Trader application. There’s a place where you can read about the application, and then it’s been published to Windows Azure – the production platform – and you can use it, explore, and see how it performs. I use this application all the time to demonstrate Windows Azure, or a particular part of Windows Azure. The advantage is that this is an end-to-end application, and online as well. The disadvantage is that it takes a bit of self-learning to work through.  Links: Learn it: http://msdn.microsoft.com/en-us/netframework/bb499684 Use it: https://azurestocktrader.cloudapp.net/

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  • Triggering custom events in AJAX callbacks

    - by Sabrina Gelbart
    I'm pretty new to JavaScript, but one of the things that's been frustrating is that our AJAX callbacks have been getting packed with different functionality, making it difficult to keep everything separated and organized. I'm really new to programming, I have a feeling learning MVC a bit more would help me, but for now using custom events seems like it could help me keep my code a lot cleaner and prevent some problems. Here's what I'm talking about: function myAjaxFunction(){ $.post('ajax/test.html', function(data) { $(document).trigger('testDataLoaded',data); }); } function myOtherFunctionThatsDependentUponAjax(){ $(document).one('testDataLoaded', function(data){ alert (data); } } I also don't know if it's ok that I'm triggering document or not... Are there any patterns that look like this that I can read more about? What are the potential problems with this?

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  • Windows Azure End to End Examples

    - by BuckWoody
    I’m fascinated by the way people learn. I’m told there are several methods people use to understand new information, from reading to watching, from experiencing to exploring. Personally, I use multiple methods of learning when I encounter a new topic, usually starting with reading a bit about the concepts. I quickly want to put those into practice, however, especially in the technical realm. I immediately look for examples where I can start trying out the concepts. But I often want a “real” example – not just something that represents the concept, but something that is real-world, showing some feature I could actually use. And it’s no different with the Windows Azure platform – I like finding things I can do now, and actually use. So when I started learning Windows Azure, I of course began with the Windows Azure Training Kit – which has lots of examples and labs, presentations and so on. But from there, I wanted more examples I could learn from, and eventually teach others with. I was asked if I would write a few of those up, so here are the ones I use. CodePlex CodePlex is Microsoft’s version of an “Open Source” repository. Anyone can start a project, add code, documentation and more to it and make it available to the world, free of charge, using various licenses as they wish. Microsoft also uses this location for most of the examples we publish, and sample databases for SQL Server. If you search in CodePlex for “Azure”, you’ll come back with a list of projects that folks have posted, including those of us at Microsoft. The source code and documentation are there, so you can learn using actual examples of code that will do what you need. There’s everything from a simple table query to a full project that is sort of a “Corporate Dropbox” that uses Windows Azure Storage. The advantage is that this code is immediately usable. It’s searchable, and you can often find a complete solution to meet your needs. The disadvantage is that the code is pretty specific – it may not cover a huge project like you’re looking for. Also, depending on the author(s), you might not find the documentation level you want. Link: http://azureexamples.codeplex.com/site/search?query=Azure&ac=8    Tailspin Microsoft Patterns and Practices is a group here that does an amazing job at sharing standard ways of doing IT – from operations to coding. If you’re not familiar with this resource, make sure you read up on it. Long before I joined Microsoft I used their work in my daily job – saved a ton of time. It has resources not only for Windows Azure but other Microsoft software as well. The Patterns and Practices group also publishes full books – you can buy these, but many are also online for free. There’s an end-to-end example for Windows Azure using a company called “Tailspin”, and the work covers not only the code but the design of the full solution. If you really want to understand the thought that goes into a Platform-as-a-Service solution, this is an excellent resource. The advantages are that this is a book, it’s complete, and it includes a discussion of design decisions. The disadvantage is that it’s a little over a year old – and in “Cloud” years that’s a lot. So many things have changed, improved, and have been added that you need to treat this as a resource, but not the only one. Still, highly recommended. Link: http://msdn.microsoft.com/en-us/library/ff728592.aspx Azure Stock Trader Sometimes you need a mix of a CodePlex-style application, and a little more detail on how it was put together. And it would be great if you could actually play with the completed application, to see how it really functions on the actual platform. That’s the Azure Stock Trader application. There’s a place where you can read about the application, and then it’s been published to Windows Azure – the production platform – and you can use it, explore, and see how it performs. I use this application all the time to demonstrate Windows Azure, or a particular part of Windows Azure. The advantage is that this is an end-to-end application, and online as well. The disadvantage is that it takes a bit of self-learning to work through.  Links: Learn it: http://msdn.microsoft.com/en-us/netframework/bb499684 Use it: https://azurestocktrader.cloudapp.net/

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  • Procedural landscape generation but not just fractals

    - by Richard Fabian
    In large procedural landscape games, the land seems dull, but that's probably because the real world is largely dull, with only limited places where the scenery is dramatic or tactical. Looking at world generation from this point of view, a landscape generator for a game needs to not follow the rules of landscaping, but instead some rules married to the expectations of the gamer. For example, there could be a choke point / route generator that creates hills ravines, rivers and mountains between cities, rather than cities plotted on the land based on the resources or conditions generated by the mountains and rainfall patterns. Is there any existing work being done like this? Start with cities or population centres and then add in terrain afterwards?

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