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  • java - check if string ends with certain pattern

    - by The Learner
    I have string like: This.is.a.great.place.too.work. (or) This/is/a/great/place/too/work/ than my java program should give me that the sentence is valid and it has "work". if i Have : This.is.a.great.place.too.work.hahahha (or) This/is/a/great/place/too/work/hahahah Should not give me that there is a work in the sentance. so I am looking at java strings to find a word at the end of the sentance having . (or),(or)/ before it. How can I achieve that

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  • Best Practice, objects design ASP.NET MVC

    - by DoomStone
    Hello Stackoverflow I have a code design question that have been torbeling me for a while, you see I’m doing a refactoring of my website Cosplay Denmark, a site where cospalyers can upload images of them self in their costumes. The original site was done in php, Zend MVC, but my refactoring is being done in ASP.NET MVC 2. If you take the site http://www.cosplaydanmark.dk/Costumes/ (You can switch to English in the left column (Sprog)) Here you see a list of all the anime’s we have on the site with images, we show the name, how many different characters and how many images there are under this anime. http://www.cosplaydanmark.dk/Costumes/Bleach If you click on an anime will you get a list of characters within the given anime which we have images in, here do we show the character name, how many galleries and how many images. http://www.cosplaydanmark.dk/Costumes/Bleach/Ichigo_Kurosaki/ If you click on the character name, will you get a list of the galleries under the given character in the given anime. Here we have some information about the gallery, such as image count. http://www.cosplaydanmark.dk/Costumes/Bleach/Ichigo_Kurosaki/Admi/ Should you click the gallery do you get a list of the images in the gallery. My database look like this at the moment. As you can might imagine there are a lot of different query’s to create the site, on the first site I need to do a select on the on the “animes” table and for each result, I need to do a count select on characters and galleries. My plan to create this will be one of the following Where the IList, would be a lazy load list. But I can’t decide what would be the best solution for this would be, also if there is a better way of doing this. My priority is to have good performance with a minimum lose of features and code upkeep. I’m using a service pattern with a linq to sql repository. My design is not absolute, I’m willing to change it if it could increase performance :D I hope that I have describe my question good enough for you to understand what I mean, but ask away if there are anything I have missed.

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  • Does my use of the strategy pattern violate the fundamental MVC pattern in iOS?

    - by Goodsquirrel
    I'm about to use the 'strategy' pattern in my iOS app, but feel like my approach violates the somehow fundamental MVC pattern. My app is displaying visual "stories", and a Story consists (i.e. has @properties) of one Photo and one or more VisualEvent objects to represent e.g. animated circles or moving arrows on the photo. Each VisualEvent object therefore has a eventType @property, that might be e.g. kEventTypeCircle or kEventTypeArrow. All events have things in common, like a startTime @property, but differ in the way they are being drawn on the StoryPlayerView. Currently I'm trying to follow the MVC pattern and have a StoryPlayer object (my controller) that knows about both the model objects (like Story and all kinds of visual events) and the view object StoryPlayerView. To chose the right drawing code for each of the different visual event types, my StoryPlayer is using a switch statement. @implementation StoryPlayer // (...) - (void)showVisualEvent:(VisualEvent *)event onStoryPlayerView:storyPlayerView { switch (event.eventType) { case kEventTypeCircle: [self showCircleEvent:event onStoryPlayerView:storyPlayerView]; break; case kEventTypeArrow: [self showArrowDrawingEvent:event onStoryPlayerView:storyPlayerView]; break; // (...) } But switch statements for type checking are bad design, aren't they? According to Uncle Bob they lead to tight coupling and can and should almost always be replaced by polymorphism. Having read about the "Strategy"-Pattern in Head First Design Patterns, I felt this was a great way to get rid of my switch statement. So I changed the design like this: All specialized visual event types are now subclasses of an abstract VisualEvent class that has a showOnStoryPlayerView: method. @interface VisualEvent : NSObject - (void)showOnStoryPlayerView:(StoryPlayerView *)storyPlayerView; // abstract Each and every concrete subclass implements a concrete specialized version of this drawing behavior method. @implementation CircleVisualEvent - (void)showOnStoryPlayerView:(StoryPlayerView *)storyPlayerView { [storyPlayerView drawCircleAtPoint:self.position color:self.color lineWidth:self.lineWidth radius:self.radius]; } The StoryPlayer now simply calls the same method on all types of events. @implementation StoryPlayer - (void)showVisualEvent:(VisualEvent *)event onStoryPlayerView:storyPlayerView { [event showOnStoryPlayerView:storyPlayerView]; } The result seems to be great: I got rid of the switch statement, and if I ever have to add new types of VisualEvents in the future, I simply create new subclasses of VisualEvent. And I won't have to change anything in StoryPlayer. But of cause this approach violates the MVC pattern since now my model has to know about and depend on my view! Now my controller talks to my model and my model talks to the view calling methods on StoryPlayerView like drawCircleAtPoint:color:lineWidth:radius:. But this kind of calls should be controller code not model code, right?? Seems to me like I made things worse. I'm confused! Am I completely missing the point of the strategy pattern? Is there a better way to get rid of the switch statement without breaking model-view separation?

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  • 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!

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  • The Dispose Pattern (and FxCop warnings)

    - by Scott Dorman
    [This is actually a response to Bill’s blog post, but since it isn’t possible to leave this as a comment on his blog it’s a post here.] There are many different ways to implement the Dispose pattern correctly. Some are (in my opinion) better than others. In Bill’s blog post he presents a particular pattern, which is an excerpt from his book (Effective C#). The issue centers around the fact that a reader took the code sample presented in the book and ran FxCop (Code Analysis) on it, which generated a warning: “Ensure that base.Dispose() is always called.” The “lesson learned” that Bill presents is that “tools are there to help us, not control us.” While I completely agree with the belief that tools are there to help us, I think it’s important to understand why FxCop is raising this particular warning. The code presented in Bill’s book looks like: // Have its own disposed flag.private bool disposed = false;protected override void Dispose(bool isDisposing){ // Don't dispose more than once. if (disposed) return; if (isDisposing) { // TODO: free managed resources here. } // TODO: free unmanaged resources here. // Let the base class free its resources. // Base class is responsible for calling // GC.SuppressFinalize( ) base.Dispose(isDisposing); // Set derived class disposed flag: disposed = true;} This code does follow all of the guidelines for implementing the Dispose pattern. In this case, it’s presumably part of a larger example showing how to implement the pattern as part of a base class. The reason FxCop is warning you about this code is the first if statement in the Dispose method, which will cause the method to exit if disposed is true. The problem here is that there is the possibility that if the disposed flag is true, the call to base.Dispose() will never be executed. As Bill points out, it is possible for some other code elsewhere in the class to set this flag. He states that this is an “unlikely occurrence.” While that is probably true, it can be a potentially dangerous assumption to make and is one that can be easily corrected. By changing the code slightly you can remove this assumption and correct the FxCop violation. private bool disposed = false;protected override void Dispose(bool disposing){ if (!disposed) { if (disposing) { // Dispose managed resources. } // Dispose unmanaged resources. disposed = true; } base.Dispose(disposing);} Using this implementation allows the call to base.Dispose() to always occur, which ensures that the the disposal chain is always properly followed. Technorati Tags: .NET,C#,Dispose Pattern

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  • How does this Singleton Web Class persists session data, even though session is not updated in the p

    - by Micah Burnett
    Ok, I've got this singleton-like web class which uses session to maintain state. I initially thought I was going to have to manipulate the session variables on each "set" so that the new values were updated in the session. However I tried using it as-is, and somehow, it remembers state. For example, if run this code on one page: UserContext.Current.User.FirstName = "Micah"; And run this code in a different browser tab, FirstName is displayed correctly: Response.Write(UserContext.Current.User.FirstName); Can someone tell me (prove) how this data is getting persisted in the session? Here is the class: using System; using System.Collections.Generic; using System.Linq; using System.Web; public class UserContext { private UserContext() { } public static UserContext Current { get { if (System.Web.HttpContext.Current.Session["UserContext"] == null) { UserContext uc = new UserContext(); uc.User = new User(); System.Web.HttpContext.Current.Session["UserContext"] = uc; } return (UserContext)System.Web.HttpContext.Current.Session["UserContext"]; } } private string HospitalField; public string Hospital { get { return HospitalField; } set { HospitalField = value; ContractField = null; ModelType = null; } } private string ContractField; public string Contract { get { return ContractField; } set { ContractField = value; ModelType = string.Empty; } } private string ModelTypeField; public string ModelType { get { return ModelTypeField; } set { ModelTypeField = value; } } private User UserField; public User User { get { return UserField; } set { UserField = value; } } public void DoSomething() { } } public class User { public int UserId { get; set; } public string FirstName { get; set; } }

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  • How to get java singleton object manager to return any type of object?

    - by Robert
    I'm writing an interactive fiction game in java from scratch. I'm currently storing all of my game object references in a hashmap in a singleton called ObjectManager. ObjectManager has a function called get which takes an integer ID and returns the appropriate reference. The problem is that it returns a BaseObject when I need to return subclasses of BaseObject with more functionality. So, what I've done so far is I've added a getEntity function which returns BaseEntity (which is a subclass of BaseObject). However, when I need the function to return to an object that is a subclass of BaseEntity that has added, required functionality, I will need to make another function. I know there is a better way, but I don't know what it is. I know very little of design patterns, and I'm not sure which one to use here. I tried passing 'class' as a parameter, but that didn't get me anywhere. public BaseObject get(int ID){ return (BaseObject)refMap.get(ID); } public BaseEntity getEntity(int ID){ return (BaseEntity)refMap.get(ID); } Thanks, java ninjas!

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  • Pooling (Singleton) Objects Against Connection Pools

    - by kolossus
    Given the following scenario A canned enterprise application that maintains its own connection pool A homegrown client application to the enterprise app. This app is built using Spring framework, with the DAO pattern While I may have a simplistic view of this, I think the following line of thinking is sound: Having a fixed pool of DAO objects, holding on to connection objects from the pool. Clearly, the pool should be capable of scaling up (or down depending on need) and the connection objects must outnumber the DAOs by a healthy margin. Good Instantiating brand new DAOs for every request to access the enterprise app; each DAO will attempt to grab a connection from the pool and release it when it's done. Bad Since these are service objects, there will be no (mutable) state held by the objects (reduced risk of concurrency issues) I also think that with #1, there should be little to no resource contention, while in #2, there'll almost always be a DAO waiting to be serviced. Is my thinking correct and what could go wrong?

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  • Pattern for Accessing MySQL connection

    - by Dipan Mehta
    We have an application which is C++ trying to access MySQL database. There are several (about 5 or so) threads in the application (with Boost library for threading) and in each thread has a few objects, each of which is trying to access Database for its' own purpose. It has a simple ORM kind of model but that really is not an important factor here. There are three potential access patterns i can think of: There could be single connection object per application or thread and is shared between all (or group). The object needs to be thread safe and there will be contentions but MySQL will not be fired with too many connections. Every object could initiate connection on its own. The database needs to take care of concurrency (which i think MySQL can) and the design could be much simpler. There could be two possibilities here. a. either object keeps a persistent connection for its life OR b. object initiate connection as and when needed. To simplify the contention as in case of 1 and not to create too many sockets as in case of 2, we can have group/set based connections. So there could be there could be more than one connection (say N), each of this connection could be shared connection across M objects. Naturally, each of the pattern has different resource cost and would work under different constraints and objectives. What criteria should i use to choose the pattern of this for my own application? What are some of the advantages and disadvantages of each of these pattern over the other? Are there any other pattern which is better? PS: I have been through these questions: mysql, one connection vs multiple and MySQL with mutiple threads and processes But they don't quite answer exactly what i am trying to ask.

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  • Using visitor pattern with large object hierarchy

    - by T. Fabre
    Context I've been using with a hierarchy of objects (an expression tree) a "pseudo" visitor pattern (pseudo, as in it does not use double dispatch) : public interface MyInterface { void Accept(SomeClass operationClass); } public class MyImpl : MyInterface { public void Accept(SomeClass operationClass) { operationClass.DoSomething(); operationClass.DoSomethingElse(); // ... and so on ... } } This design was, however questionnable, pretty comfortable since the number of implementations of MyInterface is significant (~50 or more) and I didn't need to add extra operations. Each implementation is unique (it's a different expression or operator), and some are composites (ie, operator nodes that will contain other operator/leaf nodes). Traversal is currently performed by calling the Accept operation on the root node of the tree, which in turns calls Accept on each of its child nodes, which in turn... and so on... But the time has come where I need to add a new operation, such as pretty printing : public class MyImpl : MyInterface { // Property does not come from MyInterface public string SomeProperty { get; set; } public void Accept(SomeClass operationClass) { operationClass.DoSomething(); operationClass.DoSomethingElse(); // ... and so on ... } public void Accept(SomePrettyPrinter printer) { printer.PrettyPrint(this.SomeProperty); } } I basically see two options : Keep the same design, adding a new method for my operation to each derived class, at the expense of maintainibility (not an option, IMHO) Use the "true" Visitor pattern, at the expense of extensibility (not an option, as I expect to have more implementations coming along the way...), with about 50+ overloads of the Visit method, each one matching a specific implementation ? Question Would you recommand using the Visitor pattern ? Is there any other pattern that could help solve this issue ?

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  • How does this Singleton-like web class persists session data, even though session is not updated in

    - by Micah Burnett
    Ok, I've got this singleton-like web class which uses session to maintain state. I initially thought I was going to have to manipulate the session variables on each "set" so that the new values were updated in the session. However I tried using it as-is, and somehow, it remembers state. For example, if run this code on one page: UserContext.Current.User.FirstName = "Micah"; And run this code in a different browser tab, FirstName is displayed correctly: Response.Write(UserContext.Current.User.FirstName); Can someone tell me (prove) how this data is getting persisted in the session? Here is the class: using System; using System.Collections.Generic; using System.Linq; using System.Web; public class UserContext { private UserContext() { } public static UserContext Current { get { if (System.Web.HttpContext.Current.Session["UserContext"] == null) { UserContext uc = new UserContext(); uc.User = new User(); System.Web.HttpContext.Current.Session["UserContext"] = uc; } return (UserContext)System.Web.HttpContext.Current.Session["UserContext"]; } } private string HospitalField; public string Hospital { get { return HospitalField; } set { HospitalField = value; ContractField = null; ModelType = null; } } private string ContractField; public string Contract { get { return ContractField; } set { ContractField = value; ModelType = string.Empty; } } private string ModelTypeField; public string ModelType { get { return ModelTypeField; } set { ModelTypeField = value; } } private User UserField; public User User { get { return UserField; } set { UserField = value; } } public void DoSomething() { } } public class User { public int UserId { get; set; } public string FirstName { get; set; } } I added this to a watch, and can see that the session variable is definitely being set somewhere: (UserContext)System.Web.HttpContext.Current.Session["UserContext"]; As soon as a setter is called the Session var is immediately updated: set { HospitalField = value; //<--- here ContractField = null; ModelType = null; }

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  • MVC Architecture

    Model-View-Controller (MVC) is an architectural design pattern first written about and implemented by  in 1978. Trygve developed this pattern during the year he spent working with Xerox PARC on a small talk application. According to Trygve, “The essential purpose of MVC is to bridge the gap between the human user's mental model and the digital model that exists in the computer. The ideal MVC solution supports the user illusion of seeing and manipulating the domain information directly. The structure is useful if the user needs to see the same model element simultaneously in different contexts and/or from different viewpoints.”  Trygve Reenskaug on MVC The MVC pattern is composed of 3 core components. Model View Controller The Model component referenced in the MVC pattern pertains to the encapsulation of core application data and functionality. The primary goal of the model is to maintain its independence from the View and Controller components which together form the user interface of the application. The View component retrieves data from the Model and displays it to the user. The View component represents the output of the application to the user. Traditionally the View has read-only access to the Model component because it should not change the Model’s data. The Controller component receives and translates input to requests on the Model or View components. The Controller is responsible for requesting methods on the model that can change the state of the model. The primary benefit to using MVC as an architectural pattern in a project compared to other patterns is flexibility. The flexibility of MVC is due to the distinct separation of concerns it establishes with three distinct components.  Because of the distinct separation between the components interaction is limited through the use of interfaces instead of classes. This allows each of the components to be hot swappable when the needs of the application change or needs of availability change. MVC can easily be applied to C# and the .Net Framework. In fact, Microsoft created a MVC project template that will allow new project of this type to be created with the standard MVC structure in place before any coding begins. The project also creates folders for the three key components along with default Model, View and Controller classed added to the project. Personally I think that MVC is a great pattern in regards to dealing with web applications because they could be viewed from a myriad of devices. Examples of devices include: standard web browsers, text only web browsers, mobile phones, smart phones, IPads, IPhones just to get started. Due to the potentially increasing accessibility needs and the ability for components to be hot swappable is a perfect fit because the core functionality of the application can be retained and the View component can be altered based on the client’s environment and the View component could be swapped out based on the calling device so that the display is targeted to that specific device.

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  • iOS - Unit tests for KVO/delegate codes

    - by ZhangChn
    I am going to design a MVC pattern. It could be either designed as a delegate pattern, or a Key-Value-Observing(KVO), to notify the controller about changing models. The project requires certain quality control procedures to conform to those verification documents. My questions: Does delegate pattern fit better for unit testing than KVO? If KVO fits better, would you please suggest some sample codes?

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  • How to create a manager class without global variables nor singletons?

    - by Omega
    I would like to implement some kind of manager class in my application. It will be in charge of loading textures, processing them, distributing them etc... At first, I wanted to make a global variable that simply contains an instance of my manager class. I found this question: http://stackoverflow.com/questions/4646577/global-variables-in-java. However, the users there seem to recommend to never use global variables. Fine then, I once heard about Singletons, so I though I could use that instead. I mean, creating just one instance of my manager class sounds good. However, I found this other question: When is Singleton appropriate?, which basically tells me that Singletons are, in most scenarios, some kind of anti-pattern. Now I am a bit lost - what other approach can I take to create my manager class, whose only requirement is to be accessible from anywhere?

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  • Static Access To Multiple Instance Variable

    - by Qua
    I have a singleton instance that is referenced throughout the project which works like a charm. It saves me the trouble from having to pass around an instance of the object to every little class in the project. However, now I need to manage multiple instances of the previous setup, which means that the singleton pattern breaks since each instance would need it's own singleton instance. What options are there to still maintain static access to the singleton? To be more specific, we have our game engine and several components and plugins reference the engine through a static property. Now our server needs to host multiple game instances each having their own engine, which means that on the server side the singleton pattern breaks. I'm trying to avoid all the classes having the engine in the constructor.

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  • Singleton code linker errors in vc 9.0. Runs fine in linux compiled with gcc

    - by user306560
    I have a simple logger that is implemented as a singleton. It works like i want when I compile and run it with g++ in linux but when I compile in Visual Studio 9.0 with vc++ I get the following errors. Is there a way to fix this? I don't mind changing the logger class around, but I would like to avoid changing how it is called. 1>Linking... 1>loggerTest.obj : error LNK2005: "public: static class Logger * __cdecl Logger::getInstance(void)" (?getInstance@Logger@@SAPAV1@XZ) already defined in Logger.obj 1>loggerTest.obj : error LNK2005: "public: void __thiscall Logger::log(class std::basic_string<char,struct std::char_traits<char>,class std::allocator<char> > const &)" (?log@Logger@@QAEXABV?$basic_string@DU?$char_traits@D@std@@V?$allocator@D@2@@std@@@Z) already defined in Logger.obj 1>loggerTest.obj : error LNK2005: "public: void __thiscall Logger::closeLog(void)" (?closeLog@Logger@@QAEXXZ) already defined in Logger.obj 1>loggerTest.obj : error LNK2005: "private: static class Logger * Logger::_instance" (?_instance@Logger@@0PAV1@A) already defined in Logger.obj 1>Logger.obj : error LNK2001: unresolved external symbol "private: static class std::basic_string<char,struct std::char_traits<char>,class std::allocator<char> > Logger::_path" (?_path@Logger@@0V?$basic_string@DU?$char_traits@D@std@@V?$allocator@D@2@@std@@A) 1>loggerTest.obj : error LNK2001: unresolved external symbol "private: static class std::basic_string<char,struct std::char_traits<char>,class std::allocator<char> > Logger::_path" (?_path@Logger@@0V?$basic_string@DU?$char_traits@D@std@@V?$allocator@D@2@@std@@A) 1>Logger.obj : error LNK2001: unresolved external symbol "private: static class boost::mutex Logger::_mutex" (?_mutex@Logger@@0Vmutex@boost@@A) 1>loggerTest.obj : error LNK2001: unresolved external symbol "private: static class boost::mutex Logger::_mutex" (?_mutex@Logger@@0Vmutex@boost@@A) 1>Logger.obj : error LNK2001: unresolved external symbol "private: static class std::basic_ofstream<char,struct std::char_traits<char> > Logger::_log" (?_log@Logger@@0V?$basic_ofstream@DU?$char_traits@D@std@@@std@@A) 1>loggerTest.obj : error LNK2001: unresolved external symbol "private: static class std::basic_ofstream<char,struct std::char_traits<char> > Logger::_log" (?_log@Logger@@0V?$basic_ofstream@DU?$char_traits@D@std@@@std@@A) The code, three files Logger.h Logger.cpp test.cpp #ifndef __LOGGER_CPP__ #define __LOGGER_CPP__ #include "Logger.h" Logger* Logger::_instance = 0; //string Logger::_path = "log"; //ofstream Logger::_log; //boost::mutex Logger::_mutex; Logger* Logger::getInstance(){ { boost::mutex::scoped_lock lock(_mutex); if(_instance == 0) { _instance = new Logger; _path = "log"; } } //mutex return _instance; } void Logger::log(const std::string& msg){ { boost::mutex::scoped_lock lock(_mutex); if(!_log.is_open()){ _log.open(_path.c_str()); } if(_log.is_open()){ _log << msg.c_str() << std::endl; } } } void Logger::closeLog(){ Logger::_log.close(); } #endif ` ... #ifndef __LOGGER_H__ #define __LOGGER_H__ #include <iostream> #include <string> #include <fstream> #include <boost/thread/mutex.hpp> #include <boost/thread.hpp> using namespace std; class Logger { public: static Logger* getInstance(); void log(const std::string& msg); void closeLog(); protected: Logger(){} private: static Logger* _instance; static string _path; static bool _logOpen; static ofstream _log; static boost::mutex _mutex; //check mutable }; #endif test.cpp ` #include <iostream> #include "Logger.cpp" using namespace std; int main(int argc, char *argv[]) { Logger* log = Logger::getInstance(); log->log("hello world\n"); return 0; }

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  • Ranking based string matching algorithm..for Midi Music

    - by Taha
    i am working on midi music project. What i am trying to do is:- matching the Instrument midi track with the similar instrument midi track... for example Flute track in a some midi music is matched against the Flute track in some other music midi file... After matching ,the results should come ranking wise according to their similarity.. Like 1) track1 2) track2 3) track3 I have this sort of string coming from my midi music .. F4/0.01282051282051282E4/0.01282051282051282Eb4/0.01282051282051282 D4/0.01282051282051282C#4/0.01282051282051282C4/0.01282051282051282 Which ranking algorithm with good metrics should i use for such data ? Thanking you in anticipation!

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  • Static classes and/or singletons -- How many does it take to become a code smell?

    - by Earlz
    In my projects I use quite a lot of static classes. These are usually classes that naturally seem to fit into a single-instance type of thing. Many times I use static classes and recently I've started using some singletons. How many of these does it take to become a code smell? For instance, in my recent project which has a lot of static classes is an Authentication library for ASP.Net. I use a static class for a helper class that fixes ASP.Net error codes so it can be used like CustomErrorsFixer.Fix(Context); Or my authentication class itself is a static class //in global.asax's begin_application Authentication.SomeState="blah"; Authentication.SomeOption=true; //etc //in global.asax's begin_request Authentication.Authenticate(); When are static or singleton classes bad to use? Am I doing it wrong, or am I just in a project that by definition has very little per-instance state associated with it? The only per-instance state I have is stored in HttpContext.Current.Items like so: /// <summary> /// The current user logged in for the HTTP request. If there is not a user logged in, this will be null. /// </summary> public static UserData CurrentUser{ get{ return HttpContext.Current.Items["fscauth_currentuser"] as UserData; //use HttpContext.Current as a little place to persist static data for this request } private set{ HttpContext.Current.Items["fscauth_currentuser"]=value; } }

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  • using sed to replace two patterns within a larger pattern

    - by Hair of the Dog
    Using sed how could I replace two patterns within a larger pattern on a single line? Given a single line of text I want to find a pattern (Let's call this the outer pattern) and then within that outer pattern replace two inner patterns. Here's a one line example of the input text: Z:\source\private\main\developer\foo\setenv.sh(25): export 'FONTCONFIG_PATH'="$WINE_SHARED_SUPPORT/X11/etc/fonts" In the example above the outer pattern is "/^.*([[:digit:]]+):/" which should equal "Z:\source\private\main\developer\foo\setenv.sh(25):" The two inner patterns are "/^[A-Za-z]:/" and "/\/". Another way to phrase my question is: Using sed I know how to perform replacements of a pattern using the "s" command, but how do I limit the range of "s" command so it only works on the portion of the input string up to the "(25):"? The ultimate result I am trying to get is the line of text is transformed into this: /enlistments/source/private/main/developer/foo/setenv.sh(25): export 'FONTCONFIG_PATH'="$WINE_SHARED_SUPPORT/X11/etc/fonts"

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  • Expando Object and dynamic property pattern

    - by Al.Net
    I have read about 'dynamic property pattern' of Martin Fowler in his site under the tag 1997 in which he used dictionary kind of stuff to achieve this pattern. And I have come across about Expando object in c# very recently. When I see its implementation, I am able to see IDictionary implemented. So Expando object uses dictionary to store dynamic properties and is it what, Martin Fowler already defined 15 years ago?

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  • Identifying which pattern fits better.

    - by Daniel Grillo
    I'm developing a software to program a device. I have some commands like Reset, Read_Version, Read_memory, Write_memory, Erase_memory. Reset and Read_Version are fixed. They don't need parameters. Read_memory and Erase_memory need the same parameters that are Length and Address. Write_memory needs Lenght, Address and Data. For each command, I have the same steps in sequence, that are something like this sendCommand, waitForResponse, treatResponse. I'm having difficulty to identify which pattern should I use. Factory, Template Method, Strategy or other pattern. Edit I'll try to explain better taking in count the given comments and answers. I've already done this software and now I'm trying to refactoring it. I'm trying to use patterns, even if it is not necessary because I'm taking advantage of this little software to learn about some patterns. Despite I think that one (or more) pattern fits here and it could improve my code. When I want to read version of the software of my device, I don't have to assembly the command with parameters. It is fixed. So I have to send it. After wait for response. If there is a response, treat (or parse) it and returns. To read a portion of the memory (maximum of 256 bytes), I have to assembly the command using the parameters Len and Address. So I have to send it. After wait for response. If there is a response, treat (or parse) it and returns. To write a portion in the memory (maximum of 256 bytes), I have to assembly the command using the parameters Len, Address and Data. So I have to send it. After wait for response. If there is a response, treat (or parse) it and returns. I think that I could use Template Method because I have almost the same algorithm for all. But the problem is some commands are fixes, others have 2 or 3 parameters. I think that parameters should be passed on the constructor of the class. But each class will have a constructor overriding the abstract class constructor. Is this a problem for the template method? Should I use other pattern?

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  • AntFarm anti-pattern -- strategies to avoid, antidotes to help heal from

    - by alchemical
    I'm working on a 10 page web site with a database back-end. There are 500+ objects in use, trying to implement the MVP pattern in ASP.Net. I'm tracing the code-execution from a single-page, my finger has been on F-11 in Visual Studio for about 40 minutes, there seems to be no end, possibly 1000+ method calls for one web page! If it was just 50 objects that would be one thing, however, code execution snakes through all these objects just like millions of ants frantically woring in their giant dirt mound house, riddled with object tunnels. Hence, a new anti-pattern is born : AntFarm. AntFarm is also known as "OO-Madnes", "OO-Fever", OO-ADD, or simply design-pattern junkie. This is not the first time I've seen this, nor my associates at other companies. It seems that this style is being actively propogated, or in any case is a misunderstanding of the numerous OO/DP gospels going around... I'd like to introduce an anti-pattern to the anti-pattern: GST or "Get Stuff Done" AKA "Get Sh** done" AKA GRD (GetRDone). This pattern focused on just what it says, getting stuff done, in a simple way. I may try to outline it more in a later post, or please share your ideas on this antidote pattern. Anyway, I'm in the midst of a great example of AntFarm anti-pattern as I write (as a bonus, there is no documentation or comments). Please share you thoughts on how this anti-pattern has become so prevelant, how we can avoid it, and how can one undo or deal with this pattern in a live system one must work with!

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  • Patterns: Local Singleton vs. Global Singleton?

    - by Mike Rosenblum
    There is a pattern that I use from time to time, but I'm not quite sure what it is called. I was hoping that the SO community could help me out. The pattern is pretty simple, and consists of two parts: A singleton factory, which creates objects based on the arguments passed to the factory method. Objects created by the factory. So far this is just a standard "singleton" pattern or "factory pattern". The issue that I'm asking about, however, is that the singleton factory in this case maintains a set of references to every object that it ever creates, held within a dictionary. These references can sometimes be strong references and sometimes weak references, but it can always reference any object that it has ever created. When receiving a request for a "new" object, the factory first searches the dictionary to see if an object with the required arguments already exits. If it does, it returns that object, if not, it returns a new object and also stores a reference to the new object within the dictionary. This pattern prevents having duplicative objects representing the same underlying "thing". This is useful where the created objects are relatively expensive. It can also be useful where these objects perform event handling or messaging - having one object per item being represented can prevent multiple messages/events for a single underlying source. There are probably other reasons to use this pattern, but this is where I've found this useful. My question is: what to call this? In a sense, each object is a singleton, at least with respect to the data it contains. Each is unique. But there are multiple instances of this class, however, so it's not at all a true singleton. In my own personal terminology, I tend to call the factory method a "global singleton". I then call the created objects "local singletons". I sometimes also say that the created objects have "reference equality", meaning that if two variables reference the same data (the same underlying item) then the reference they each hold must be to the same exact object, hence "reference equality". But these are my own invented terms, and I am not sure that they are good ones. Is there standard terminology for this concept? And if not, could some naming suggestions be made? Thanks in advance...

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