Search Results

Search found 5636 results on 226 pages for 'facade pattern'.

facebook twitter digg google delicious technorati stumbleupon myspace wordpress linkedin gmail igoogle windows live tumblr viadeo yahoo buzz yahoo mail yahoo bookmarks favorites email print

Page 10/226 | < Previous Page | 6 7 8 9 10 11 12 13 14 15 16 17  | Next Page >

  • Design Pattern for building a Budget

    - by Scott
    So I've looked at the Builder Pattern, Abstract Interfaces, other design patterns, etc. - and I think I'm over thinking the simplicity behind what I'm trying to do, so I'm asking you guys for some help with either recommending a design pattern I should use, or an architecture style I'm not familiar with that fits my task. So I have one model that represents a Budget in my code. At a high level, it looks like this: public class Budget { public int Id { get; set; } public List<MonthlySummary> Months { get; set; } public float SavingsPriority { get; set; } public float DebtPriority { get; set; } public List<Savings> SavingsCollection { get; set; } public UserProjectionParameters UserProjectionParameters { get; set; } public List<Debt> DebtCollection { get; set; } public string Name { get; set; } public List<Expense> Expenses { get; set; } public List<Income> IncomeCollection { get; set; } public bool AutoSave { get; set; } public decimal AutoSaveAmount { get; set; } public FundType AutoSaveType { get; set; } public decimal TotalExcess { get; set; } public decimal AccountMinimum { get; set; } } To go into more detail about some of the properties here shouldn't be necessary, but if you have any questions about those I will fill more out for you guys. Now, I'm trying to create code that builds one of these things based on a set of BudgetBuildParameters that the user will create and supply. There are going to be multiple types of these parameters. For example, on the sites homepage, there will be an example section where you can quickly see what your numbers look like, so they would be a much simpler set of SampleBudgetBuildParameters then say after a user registers and wants to create a fully filled out Budget using much more information in the DebtBudgetBuildParameters. Now a lot of these builds are going to be using similar code for certain tasks, but might want to also check the status of a users DebtCollection when formulating a monthly spending report, where as a Budget that only focuses on savings might not want to. I'd like to reduce code duplication (obviously) as much as possible, but in my head, every way I can think to do this would require using a base BudgetBuilderFactory to return the correct builder to the caller, and then creating say a SimpleBudgetBuilder that inherits from a BudgetBuilder, and put all duplicate code in the BudgetBuilder, and let the SimpleBudgetBuilder handle it's own cases. Problem is, a lot of the unique cases are unique to 2/4 builders, so there will be duplicate code somewhere in there obviously if I did that. Can anyone think of a better way to either explain a solution to this that may or may not be similar to mine, or a completely different pattern or way of thinking here? I really appreciate it.

    Read the article

  • MVC Communication Pattern

    - by Kedu
    This is kind of a follow up question to this http://stackoverflow.com/questions/23743285/model-view-controller-and-callbacks, but I wanted to post it separately, because its kind of a different topic. I'm working on a multiplayer cardgame for the Android platform. I split the project into MVC which fits the needs pretty good, but I'm currently stuck because I can't figure out a good way to communicate between the different parts. I have everything setup and working with the controller being a big state machine, which is called over and over from the gameloop, and calls getter methods from the GUI and the android/network part to get the input. The input itself in the GUI and network is set by inputlisteners that set a local variable which I read in the getter method. So far so good, this is working. But my problem is, the controller has to check every input separately,so if I want to add an input I have to check in which states its valid and call the getter method from all these states. This is not good, and lets the code look pretty ugly, makes additions uncomfortable and adds redundance. So what I've got from the question I mentioned above is that some kind of command or event pattern will fit my needs. What I want to do is to create a shared and threadsafe queue in the controller and instead of calling all these getter methods, I just check the queue for new input and proceed it. On the other side, the GUI and network don't have all these getters, but instead create an event or command and send it to the controller through, for example, observer/observable. Now my problem: I can't figure out a way, for these commands/events to fit a common interface (which the queue can store) and still transport different kind of data (button clicks, cards that are played, the player id the command comes from, synchronization data etc.). If I design the communication as command pattern, I have to stick all the information that is needed to execute the command into it when its created, that's impossible because the GUI or network has no knowledge of all the things the controller needs to execute stuff that needs to be done when for example a card is played. I thought about getting this stuff into the command when executing it. But over all the different commands I have, I would need all the information the controller has, and thus give the command a reference to the controller which would make everything in it public, which is real bad design I guess. So, I could try some kind of event pattern. I have to transport data in the event. So, like the command, I would have an interface, which all events have in common, and can be stored in the shared queue. I could create a big enum with all the different events that a are possible, save one of these enums in the actual event, and build a big switch case for the events, to proceed different stuff for different events. The problem here: I have different data for all the events. But I need a common interface, to store the events in a queue. How do I get the specific data, if I can only access the event through the interface? Even if that wouldn't be a problem, I'm creating another big switch case, which looks ugly, and when i want to add a new event, I have to create the event itself, the case, the enum, and the method that's called with the data. I could of course check the event with the enum and cast it to its type, so I can call event type specific methods that give me the data I need, but that looks like bad design too.

    Read the article

  • Java session facade not being found via InitialContext lookups

    - by Hugh Buchanan
    I have a project that is Java EE 5 running on Glassfish. The IDE is Netbeans 6.7.1. We periodically have a very annoying problem with new session facades not being located via InitialContext: javax.naming.NameNotFoundException: No object bound to name java:comp/env/GlobalConfigEntityFacadeLocal In my class (within the same EJB container), I can use the other session facades just fine. This sort of problem happens periodically, and a mixture of clean&build and deleting the build-impl.xml files from nbproject sometimes resolve this. We are not using ejb-jar.xml (stopped using that over a year ago, it is now an empty The code that is calling this is very straight forward: GlobalConfigEntityFacadeLocal globalConfigEntityFacade = null; try { InitialContext ic = new InitialContext(); globalConfigEntityFacade = (GlobalConfigEntityFacadeLocal) ic.lookup("java:comp/env/GlobalConfigEntityFacadeLocal"); ... } catch ( ... ) {} Any advice would be appreciated!!!! Cheers

    Read the article

  • Design pattern for window management in a Java Swing app

    - by Lord Torgamus
    I've just started creating my very first little Java Swing app. When the program opens, it brings up a single, simple window with a label and a couple buttons. Clicking one of those buttons is supposed to wipe out the welcome screen and replace it with a totally different panel. I'm not sure what the best way to create that functionality is. One method would be to pass my JFrame as an argument into... just about every other component, but that feels hacky to me. Or, there's making each panel double as an action listener, but that doesn't seem right, either. Is there a design pattern I should be applying here? "Replace the contents of the main — and only — window" must be a reasonably common operation. A name for the pattern would be enough; I can use Google on my own from there. (I wouldn't say no to a longer explanation, though.)

    Read the article

  • Understanding C# async / await (2) Awaitable / Awaiter Pattern

    - by Dixin
    What is awaitable Part 1 shows that any Task is awaitable. Actually there are other awaitable types. Here is an example: Task<int> task = new Task<int>(() => 0); int result = await task.ConfigureAwait(false); // Returns a ConfiguredTaskAwaitable<TResult>. The returned ConfiguredTaskAwaitable<TResult> struct is awaitable. And it is not Task at all: public struct ConfiguredTaskAwaitable<TResult> { private readonly ConfiguredTaskAwaiter m_configuredTaskAwaiter; internal ConfiguredTaskAwaitable(Task<TResult> task, bool continueOnCapturedContext) { this.m_configuredTaskAwaiter = new ConfiguredTaskAwaiter(task, continueOnCapturedContext); } public ConfiguredTaskAwaiter GetAwaiter() { return this.m_configuredTaskAwaiter; } } It has one GetAwaiter() method. Actually in part 1 we have seen that Task has GetAwaiter() method too: public class Task { public TaskAwaiter GetAwaiter() { return new TaskAwaiter(this); } } public class Task<TResult> : Task { public new TaskAwaiter<TResult> GetAwaiter() { return new TaskAwaiter<TResult>(this); } } Task.Yield() is a another example: await Task.Yield(); // Returns a YieldAwaitable. The returned YieldAwaitable is not Task either: public struct YieldAwaitable { public YieldAwaiter GetAwaiter() { return default(YieldAwaiter); } } Again, it just has one GetAwaiter() method. In this article, we will look at what is awaitable. The awaitable / awaiter pattern By observing different awaitable / awaiter types, we can tell that an object is awaitable if It has a GetAwaiter() method (instance method or extension method); Its GetAwaiter() method returns an awaiter. An object is an awaiter if: It implements INotifyCompletion or ICriticalNotifyCompletion interface; It has an IsCompleted, which has a getter and returns a Boolean; it has a GetResult() method, which returns void, or a result. This awaitable / awaiter pattern is very similar to the iteratable / iterator pattern. Here is the interface definitions of iteratable / iterator: public interface IEnumerable { IEnumerator GetEnumerator(); } public interface IEnumerator { object Current { get; } bool MoveNext(); void Reset(); } public interface IEnumerable<out T> : IEnumerable { IEnumerator<T> GetEnumerator(); } public interface IEnumerator<out T> : IDisposable, IEnumerator { T Current { get; } } In case you are not familiar with the out keyword, please find out the explanation in Understanding C# Covariance And Contravariance (2) Interfaces. The “missing” IAwaitable / IAwaiter interfaces Similar to IEnumerable and IEnumerator interfaces, awaitable / awaiter can be visualized by IAwaitable / IAwaiter interfaces too. This is the non-generic version: public interface IAwaitable { IAwaiter GetAwaiter(); } public interface IAwaiter : INotifyCompletion // or ICriticalNotifyCompletion { // INotifyCompletion has one method: void OnCompleted(Action continuation); // ICriticalNotifyCompletion implements INotifyCompletion, // also has this method: void UnsafeOnCompleted(Action continuation); bool IsCompleted { get; } void GetResult(); } Please notice GetResult() returns void here. Task.GetAwaiter() / TaskAwaiter.GetResult() is of such case. And this is the generic version: public interface IAwaitable<out TResult> { IAwaiter<TResult> GetAwaiter(); } public interface IAwaiter<out TResult> : INotifyCompletion // or ICriticalNotifyCompletion { bool IsCompleted { get; } TResult GetResult(); } Here the only difference is, GetResult() return a result. Task<TResult>.GetAwaiter() / TaskAwaiter<TResult>.GetResult() is of this case. Please notice .NET does not define these IAwaitable / IAwaiter interfaces at all. As an UI designer, I guess the reason is, IAwaitable interface will constraint GetAwaiter() to be instance method. Actually C# supports both GetAwaiter() instance method and GetAwaiter() extension method. Here I use these interfaces only for better visualizing what is awaitable / awaiter. Now, if looking at above ConfiguredTaskAwaitable / ConfiguredTaskAwaiter, YieldAwaitable / YieldAwaiter, Task / TaskAwaiter pairs again, they all “implicitly” implement these “missing” IAwaitable / IAwaiter interfaces. In the next part, we will see how to implement awaitable / awaiter. Await any function / action In C# await cannot be used with lambda. This code: int result = await (() => 0); will cause a compiler error: Cannot await 'lambda expression' This is easy to understand because this lambda expression (() => 0) may be a function or a expression tree. Obviously we mean function here, and we can tell compiler in this way: int result = await new Func<int>(() => 0); It causes an different error: Cannot await 'System.Func<int>' OK, now the compiler is complaining the type instead of syntax. With the understanding of the awaitable / awaiter pattern, Func<TResult> type can be easily made into awaitable. GetAwaiter() instance method, using IAwaitable / IAwaiter interfaces First, similar to above ConfiguredTaskAwaitable<TResult>, a FuncAwaitable<TResult> can be implemented to wrap Func<TResult>: internal struct FuncAwaitable<TResult> : IAwaitable<TResult> { private readonly Func<TResult> function; public FuncAwaitable(Func<TResult> function) { this.function = function; } public IAwaiter<TResult> GetAwaiter() { return new FuncAwaiter<TResult>(this.function); } } FuncAwaitable<TResult> wrapper is used to implement IAwaitable<TResult>, so it has one instance method, GetAwaiter(), which returns a IAwaiter<TResult>, which wraps that Func<TResult> too. FuncAwaiter<TResult> is used to implement IAwaiter<TResult>: public struct FuncAwaiter<TResult> : IAwaiter<TResult> { private readonly Task<TResult> task; public FuncAwaiter(Func<TResult> function) { this.task = new Task<TResult>(function); this.task.Start(); } bool IAwaiter<TResult>.IsCompleted { get { return this.task.IsCompleted; } } TResult IAwaiter<TResult>.GetResult() { return this.task.Result; } void INotifyCompletion.OnCompleted(Action continuation) { new Task(continuation).Start(); } } Now a function can be awaited in this way: int result = await new FuncAwaitable<int>(() => 0); GetAwaiter() extension method As IAwaitable shows, all that an awaitable needs is just a GetAwaiter() method. In above code, FuncAwaitable<TResult> is created as a wrapper of Func<TResult> and implements IAwaitable<TResult>, so that there is a  GetAwaiter() instance method. If a GetAwaiter() extension method  can be defined for Func<TResult>, then FuncAwaitable<TResult> is no longer needed: public static class FuncExtensions { public static IAwaiter<TResult> GetAwaiter<TResult>(this Func<TResult> function) { return new FuncAwaiter<TResult>(function); } } So a Func<TResult> function can be directly awaited: int result = await new Func<int>(() => 0); Using the existing awaitable / awaiter - Task / TaskAwaiter Remember the most frequently used awaitable / awaiter - Task / TaskAwaiter. With Task / TaskAwaiter, FuncAwaitable / FuncAwaiter are no longer needed: public static class FuncExtensions { public static TaskAwaiter<TResult> GetAwaiter<TResult>(this Func<TResult> function) { Task<TResult> task = new Task<TResult>(function); task.Start(); return task.GetAwaiter(); // Returns a TaskAwaiter<TResult>. } } Similarly, with this extension method: public static class ActionExtensions { public static TaskAwaiter GetAwaiter(this Action action) { Task task = new Task(action); task.Start(); return task.GetAwaiter(); // Returns a TaskAwaiter. } } an action can be awaited as well: await new Action(() => { }); Now any function / action can be awaited: await new Action(() => HelperMethods.IO()); // or: await new Action(HelperMethods.IO); If function / action has parameter(s), closure can be used: int arg0 = 0; int arg1 = 1; int result = await new Action(() => HelperMethods.IO(arg0, arg1)); Using Task.Run() The above code is used to demonstrate how awaitable / awaiter can be implemented. Because it is a common scenario to await a function / action, so .NET provides a built-in API: Task.Run(): public class Task2 { public static Task Run(Action action) { // The implementation is similar to: Task task = new Task(action); task.Start(); return task; } public static Task<TResult> Run<TResult>(Func<TResult> function) { // The implementation is similar to: Task<TResult> task = new Task<TResult>(function); task.Start(); return task; } } In reality, this is how we await a function: int result = await Task.Run(() => HelperMethods.IO(arg0, arg1)); and await a action: await Task.Run(() => HelperMethods.IO());

    Read the article

  • Design pattern for animation sequence in LibGDX

    - by kevinyu
    What design pattern to use for sequence of animation that involve different actor in libGDX. For example I am making a game to choose a wolf from a group of sheeps. The first animation played when the game begin is the wolf enter the field that is filled with two sheeps.Then the wolf disguise as a sheep and goes to the center of the screen. Then the game will shuffle the sheeps. After it finished it will ask the player where is the wolf. The game wait for player input. After that the game will show animation to show the player whether their answer is right or wrong. I am currently using State design pattern. There are four states wolfEnterState,DisguiseState,ShuffleState,UserInputState, and answerAnimationState. I feel that my code is messy. I use addAction with action sequence and action completion(new Runnable()) a lot. I feel that the action sequence is getting long. Is there a better solution for this kind of problem

    Read the article

  • Am I missing a pattern?

    - by Ryan Pedersen
    I have a class that is a singleton and off of the singleton are properties that hold the instances of all the performance counters in my application. public interface IPerformanceCounters { IPerformanceCounter AccountServiceCallRate { get; } IPerformanceCounter AccountServiceCallDuration { get; } Above is an incomplete snippet of the interface for the class "PerformanceCounters" that is the singleton. I really don't like the plural part of the name and thought about changing it to "PerformanceCounterCollection" but stopped because it really isn't a collection. I also thought about "PerformanceCounterFactory" but it is really a factory either. After failing with these two names and a couple more that aren't worth mentioning I thought that I might be missing a pattern. Is there a name that make sense or a change that I could make towards a standardized pattern that would help me put some polish on this object and get rid of the plural name? I understand that I might be splitting hairs here but that is why I thought that the "Programmers" exchange was the place for this kind of thing. If it is not... I am sorry and I will not make that mistake again. Thanks!

    Read the article

  • MVP Pattern Philsophical Question - Security Checking in UI

    - by Brian
    Hello, I have a philosophical question about the MVP pattern: I have a component that checks whether a user has access to a certain privilege. This privilege turns on or off certain UI features. For instance, suppose you have a UI grid, and for each row that gets bound, I do a security check to see if certain features in the grid should be enabled or disabled. There are two ways to do this: have the UI/view call the component's method, determine if it has access, and enable/disable or show/hide. The other is have the view fire an event to the presenter, have the presenter do the check and return the access back down to the view through the model or through the event arg. As per the MVP pattern, which component should security checks fit into, the presenter or the view? Since the view is using it to determine its accessibility, it seems more fitting in the view, but it is doing database checks and all inside this business component, and there is business logic there, so I can see the reverse argument too. Thoughts? Thanks.

    Read the article

  • Confused about javascript module pattern implementation

    - by Damon
    I have a class written on a project I'm working on that I've been told is using the module pattern, but it's doing things a little differently than the examples I've seen. It basically takes this form: (function ($, document, window, undefined) { var module = { foo : bar, aMethod : function (arg) { className.bMethod(arg); }, bMethod : function (arg) { console.log('spoons'); } }; window.ajaxTable = ajaxTable; })(jQuery, document, window); I get what's going on here. But I'm not sure how this relates to most of the definitions I've seen of the module (or revealing?) module pattern. like this one from briancray var module = (function () { // private variables and functions var foo = 'bar'; // constructor var module = function () { }; // prototype module.prototype = { constructor: module, something: function () { } }; // return module return module; })(); var my_module = new module(); Is the first example basically like the second except everything is in the constructor? I'm just wrapping my head around patterns and the little things at the beginnings and endings always make me not sure what I should be doing.

    Read the article

  • 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?

    Read the article

  • Question about modeling with MVC (the pattern, not the MS stuff / non web)

    - by paul
    I'm working on an application in which I'm looking to employ the MVC pattern, but I've come up against a design decision point I could use some help with. My application is going to deal with the design of state-machines. Currently the MVC model holds information about the machine's states, inputs, outputs, etc. The view is going to show a diagram for the machine, graphically allowing the user to add new states, establish transitions, and put the states in a pleasing arrangement, among other things. I would like to store part of the diagram's state (e.g. the x and y state positions) when the machine information is stored for later retrieval, and am wondering how best to go about structuring the model(s?) for this. It seems like this UI information is more closely related to the view than to the state-machine model, so I was thinking that a secondary model might be in order, but I am reluctant to pursue this route because of the added complexity. Adding this information to the current model doesn't seem the right way to go about it either. This is the my first time using the MVC pattern so I'm still figuring things out. Any input would be appreciated.

    Read the article

  • Javascript Module pattern with DOM ready

    - by dego89
    I am writing a JS Module pattern to test out code and help me understand the pattern, using a JS Fiddle. What I can't figure out is why my "private methods" on line 25 and 26, when referenced via DOM ready, have a value of undefined. JSFiddle Code Sample: var obj = { key: "value" }; var Module = (function () { var innerVar = "5"; console.log("obj var in Module:"); console.log(obj); function privateFunction() { console.log("privateFunction() called."); innerFunction(); function innerFunction() { console.log("inner function of (private function) called."); } } function _numTwo() { console.log("_numTwo() function called."); } return { test: privateFunction, numTwo: _numTwo } }(obj)); $(document).ready(function () { console.log("$ Dom Ready"); console.log("Module in Dom Ready: "); console.log(Module.test()); });

    Read the article

  • 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.

    Read the article

  • doubleton pattern in C++

    - by benjamin button
    I am aware of the singleton pattern in C++. but what is the logic to get two instances of the object? is there any such pattern where we could easily get 2 pattern. for the logic i could think of is that i can change the singleton pattern itself to have two objects created inside the class.this works. but if the requirement grows like if i need only 3 or only 4 what is the deswign pattern that i could think of to qualify such requirement?

    Read the article

  • Who benefits from the use of Design Patterns?

    Who benefits from the use of design patterns is like asking who benefits from clean air or a good education. All of the stakeholders of a project benefit from the use of design patterns. Project Sponsor Project sponsors benefit from the use of design patterns because they promote reduced development time which translates in to shorter project timelines and greater return on investment compared to other projects that do not make use of design patterns. Project Manager Project managers benefit from the use of design patterns because they reduce the amount of time needed to design a system, and typically the sub components of the system already have a proven track record. System Architect/Engineer System architects/engineers benefit from the use of design patterns because reduce the amount of time needed to design the core a system. The additional time is used to alter the design pattern through the use of innovative design and common design principles to adhere to the project’s requirements. Programmer Programmers benefit from the use of design patterns because they can reuse existing code already established by the design pattern and only have to integrate the changes outlined by the system architects/engineers. Tester Testers benefit from the use of design patterns because they can alter the existing test established for the design pattern to take in to account the changes made by the system architects/engineers. User Users benefit from the use of design patterns because the software is typically delivered sooner than projects that do not incorporate the use of design patterns, and they are assumed that the system will work as designed because it was based on a system that was already proven to work properly.

    Read the article

  • A C# implementation of the CallStream pattern

    - by Bertrand Le Roy
    Dusan published this interesting post a couple of weeks ago about a novel JavaScript chaining pattern: http://dbj.org/dbj/?p=514 It’s similar to many existing patterns, but the syntax is extraordinarily terse and it provides a new form of friction-free, plugin-less extensibility mechanism. Here’s a JavaScript example from Dusan’s post: CallStream("#container") (find, "div") (attr, "A", 1) (css, "color", "#fff") (logger); The interesting thing here is that the functions that are being passed as the first argument are arbitrary, they don’t need to be declared as plug-ins. Compare that with a rough jQuery equivalent that could look something like this: $.fn.logger = function () { /* ... */ } $("selector") .find("div") .attr("A", 1) .css("color", "#fff") .logger(); There is also the “each” method in jQuery that achieves something similar, but its syntax is a little more verbose. Of course, that this pattern can be expressed so easily in JavaScript owes everything to the extraordinary way functions are treated in that language, something Douglas Crockford called “the very best part of JavaScript”. One of the first things I thought while reading Dusan’s post was how I could adapt that to C#. After all, with Lambdas and delegates, C# also has its first-class functions. And sure enough, it works really really well. After about ten minutes, I was able to write this: CallStreamFactory.CallStream (p => Console.WriteLine("Yay!")) (Dump, DateTime.Now) (DumpFooAndBar, new { Foo = 42, Bar = "the answer" }) (p => Console.ReadKey()); Where the Dump function is: public static void Dump(object options) { Console.WriteLine(options.ToString()); } And DumpFooAndBar is: public static void DumpFooAndBar(dynamic options) { Console.WriteLine("Foo is {0} and bar is {1}.", options.Foo, options.Bar); } So how does this work? Well, it really is very simple. And not. Let’s say it’s not a lot of code, but if you’re like me you might need an Advil after that. First, I defined the signature of the CallStream method as follows: public delegate CallStream CallStream (Action<object> action, object options = null); The delegate define a call stream as something that takes an action (a function of the options) and an optional options object and that returns a delegate of its own type. Tricky, but that actually works, a delegate can return its own type. Then I wrote an implementation of that delegate that calls the action and returns itself: public static CallStream CallStream (Action<object> action, object options = null) { action(options); return CallStream; } Pretty nice, eh? Well, yes and no. What we are doing here is to execute a sequence of actions using an interesting novel syntax. But for this to be actually useful, you’d need to build a more specialized call stream factory that comes with some sort of context (like Dusan did in JavaScript). For example, you could write the following alternate delegate signature that takes a string and returns itself: public delegate StringCallStream StringCallStream(string message); And then write the following call stream (notice the currying): public static StringCallStream CreateDumpCallStream(string dumpPath) { StringCallStream str = null; var dump = File.AppendText(dumpPath); dump.AutoFlush = true; str = s => { dump.WriteLine(s); return str; }; return str; } (I know, I’m not closing that stream; sure; bad, bad Bertrand) Finally, here’s how you use it: CallStreamFactory.CreateDumpCallStream(@".\dump.txt") ("Wow, this really works.") (DateTime.Now.ToLongTimeString()) ("And that is all."); Next step would be to combine this contextual implementation with the one that takes an action parameter and do some really fun stuff. I’m only scratching the surface here. This pattern could reveal itself to be nothing more than a gratuitous mind-bender or there could be applications that we hardly suspect at this point. In any case, it’s a fun new construct. Or is this nothing new? You tell me… Comments are open :)

    Read the article

  • How do I recursively delete all files or folders whose names match a pattern in Windows?

    - by zylstra
    For the file example, I would like to delete all files matching .+?[a-f0-9]{4}.html (i.e. any html file ending in a four digit hexadecimal). So paged47c.html would be deleted, but page.html would remain. For the folder example, I would like to delete all folders matching .+?[A-Z]+ (i.e. any folder containing a capital letter). So some-folderSE93_89ds/ would be deleted, but some-folder/ would remain. I don't work much with the command line, but I could probably get an example involving "del" to work for me. Alternatively, is there a simple GUI program for Windows that would do this?

    Read the article

  • JavaScript local alias pattern

    - by Latest Microsoft Blogs
    Here’s a little pattern that is fairly common from JavaScript developers but that is not very well known from C# developers or people doing only occasional JavaScript development. In C#, you can use a “using” directive to create aliases of namespaces Read More......(read more)

    Read the article

  • Which design pattern to use when using ORM?

    - by RPK
    I am writing a small ASP.NET Web Forms application. In my solution explorer, I added various class library projects to define layers, viz: Model Repository Presentation WebUI Someone suggested me that this layered approach is not of much sense if I am using ORM tool like PetaPoco, which itself takes care of separation of data access layer. I want to use PetaPoco micro-ORM and want to know which design pattern is suitable with ORM tools. Do I still need several class library projects to separate the concerns?

    Read the article

  • atftp pcre pattern

    - by CE-SA
    I've a question about the package named 'atftp'. I've got the atftp daemon finally working. Previously I was using tftp-hpa with a custom rule that replaces filenames with capitals into non-capital filenames and replaces the backslashes into forward slashes so that WinPE will boot fine. But in atftp I can't find rules or replacements like that. I'm searching for long, but cannot find or write the right pcre-pattern. Could you help me with this?

    Read the article

  • The Command Pattern

    In this article I will provide a quick refresher on what the command pattern is used for, how it works, and where it fits in the web development world.

    Read the article

facebook twitter digg google delicious technorati stumbleupon myspace wordpress linkedin gmail igoogle windows live tumblr viadeo yahoo buzz yahoo mail yahoo bookmarks favorites email print

< Previous Page | 6 7 8 9 10 11 12 13 14 15 16 17  | Next Page >