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  • Qt Creator draws up build issue: "target pattern contains no %. Stop."

    - by Louis93
    The compile output says no% in line 240 of the makefile. Here is an extract of that portion in the Makefile: debug/lv.simplon.class.o: c:/SimplonQt/include/lv.simplon.class.cpp $(CXX) -c $(CXXFLAGS) $(INCPATH) -o debug/lv.simplon.class.o c:/SimplonQt/include/lv.simplon.class.cpp I'm loading a project I have saved in my C drive in Windows, but I am not sure what exactly is the cause of the problem. Thanks in advance!

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  • Which type of design pattern should be used to create an emulator?

    - by Facon
    I have programmed an emulator, but I have some doubts about how to organizate it properly, because, I see that it has some problems about classes connection (CPU <- Machine Board). For example: I/O ports, interruptions, communication between two or more CPU, etc. I need for the emulator to has the best performance and good understanding of the code. PD: Sorry for my bad English. EDITED: Asking for multiple patterns.

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  • c++ Design pattern for CoW, inherited classes, and variable shared data?

    - by krunk
    I've designed a copy-on-write base class. The class holds the default set of data needed by all children in a shared data model/CoW model. The derived classes also have data that only pertains to them, but should be CoW between other instances of that derived class. I'm looking for a clean way to implement this. If I had a base class FooInterface with shared data FooDataPrivate and a derived object FooDerived. I could create a FooDerivedDataPrivate. The underlying data structure would not effect the exposed getters/setters API, so it's not about how a user interfaces with the objects. I'm just wondering if this is a typical MO for such cases or if there's a better/cleaner way? What peeks my interest, is I see the potential of inheritance between the the private data classes. E.g. FooDerivedDataPrivate : public FooDataPrivate, but I'm not seeing a way to take advantage of that polymorphism in my derived classes. class FooDataPrivate { public: Ref ref; // atomic reference counting object int a; int b; int c; }; class FooInterface { public: // constructors and such // .... // methods are implemented to be copy on write. void setA(int val); void setB(int val); void setC(int val); // copy constructors, destructors, etc. all CoW friendly private: FooDataPrivate *data; }; class FooDerived : public FooInterface { public: FooDerived() : FooInterface() {} private: // need more shared data for FooDerived // this is the ???, how is this best done cleanly? };

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  • What OOP pattern to use when only adding new methods, not data?

    - by Jonathon Reinhart
    Hello eveyone... In my app, I have deal with several different "parameters", which derive from IParameter interface, and also ParamBase abstract base class. I currently have two different parameter types, call them FooParameter and BarParameter, which both derive from ParamBase. Obviously, I can treat them both as IParameters when I need to deal with them generically, or detect their specific type when I need to handle their specific functionality. My question lies in specific FooParameters. I currently have a few specific ones with their own classes which derive from FooParameter, we'll call them FP12, FP13, FP14, etc. These all have certain characteristics, which make me treat them differently in the UI. (Most have names associated with the individual bits, or ranges of bits). Note that these specific, derived FP's have no additional data associated with them, only properties (which refer to the same data in different ways) or methods. Now, I'd like to keep all of these parameters in a Dictionary<String, IParameter> for easy generic access. The problem is, if I want to refer to a specific one with the special GUI functions, I can't write: FP12 fp12 = (FP12)paramList["FP12"] because you can't downcast to a derived type (rightfully so). But in my case, I didn't add any data, so the cast would theoretically work. What type of programming model should I be using instead? Thanks!

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  • The PROMOTE TRANSACTION request failed because there is no local transaction active.

    - by Mark J Miller
    Under what circumstances would I see the above message? I have a single call to SQL Server which is wrapped in a call to TransactionScope. In our development and QA environments MSDTC is turned off and the call succeeds fine. However, in our production environment with MSDTC turned on we are failing with this call. Is there something that would cause this when I am sure we are not looking at a distributed transaction call at all?

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  • How can I capture a multiline pattern using a regular expressions in java?

    - by lampShade
    I have a text file that I need to parse using regular expressions. The text that I need to capture is in multiline groups like this: truck zDoug Doug's house (123) 456-7890 [email protected] 30 61234.56 8/10/2003 vehicle eRob Rob's house (987) 654-3210 [email protected] For this example I need to capture truck followed by the next seven lines.In other words, in this "block" I have 8 groups. This is what I've tried but it will not capture the next line: (truck)\n(\w). NOTE: I'm using the program RegExr to test my regex before I port it to Java.

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  • How might I wrap the FindXFile-style APIs to the STL-style Iterator Pattern in C++?

    - by BillyONeal
    Hello everyone :) I'm working on wrapping up the ugly innards of the FindFirstFile/FindNextFile loop (though my question applies to other similar APIs, such as RegEnumKeyEx or RegEnumValue, etc.) inside iterators that work in a manner similar to the Standard Template Library's istream_iterators. I have two problems here. The first is with the termination condition of most "foreach" style loops. STL style iterators typically use operator!= inside the exit condition of the for, i.e. std::vector<int> test; for(std::vector<int>::iterator it = test.begin(); it != test.end(); it++) { //Do stuff } My problem is I'm unsure how to implement operator!= with such a directory enumeration, because I do not know when the enumeration is complete until I've actually finished with it. I have sort of a hack together solution in place now that enumerates the entire directory at once, where each iterator simply tracks a reference counted vector, but this seems like a kludge which can be done a better way. The second problem I have is that there are multiple pieces of data returned by the FindXFile APIs. For that reason, there's no obvious way to overload operator* as required for iterator semantics. When I overload that item, do I return the file name? The size? The modified date? How might I convey the multiple pieces of data to which such an iterator must refer to later in an ideomatic way? I've tried ripping off the C# style MoveNext design but I'm concerned about not following the standard idioms here. class SomeIterator { public: bool next(); //Advances the iterator and returns true if successful, false if the iterator is at the end. std::wstring fileName() const; //other kinds of data.... }; EDIT: And the caller would look like: SomeIterator x = ??; //Construct somehow while(x.next()) { //Do stuff } Thanks! Billy3

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  • Is There a Good Pattern for Creating a Unique Id based on a Type?

    - by Michael Kelley
    I have a template that creates a unique identifier for each type it is instanced. Here's a streamlined version of the template: template <typename T> class arType { static const arType Id; // this will be unique for every instantiation of arType<>. } // Address of Id is used for identification. #define PA_TYPE_TAG(T) (&arType<T >::Id) This works when you have an executable made purely of static libraries. Unfortunately we're moving to an executable made up of dlls. Each dlls could potentially have its own copy of Id for a type. One obvious solution is to explicitly instantiate all instances of arType. Unfortunately this is cumbersome, and I'd like to ask if anyone can propose a better solution?

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  • How can I override the attribute assignment in an active record object?

    - by ryeguy
    I know you can do this with virtual attributes, but what if the column actually exists? For example, my model has a raw_topic column. When raw_topic is set, I want artist and song_title to be set based off of raw_topic's contents. Ideally, I'd like to override the raw_topic= method, but rails doesn't seem to like that. What's the proper way of doing this? Is a callback the only way?

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  • Why getting active record error when trying to work on arrays?

    - by keruilin
    I have the following association in my User model: has_and_belongs_to_many :friends, :class_name => 'User', :foreign_key => 'friend_id' I have the following uniqueness constraint in my user_users table: UNIQUE KEY `no_duplicate_friends` (`user_id`,`friend_id`) In my code, I am retrieving a user's friends -- friends = user.friends. friends is an array. I have a scenario where I want add the user with all those friends to the friends array. Ex: friends << user_with_all_those_homies However, I get the following error: ActiveRecord::StatementInvalid: Mysql::Error: Duplicate entry '18-18' for key 'no_duplicate_friends': INSERT INTO `users_users` (`friend_id`, `user_id`) VALUES (18, 18) What gives?

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  • How to make TwoWay binding on properties of ObservableCollection of custom class using mvvm pattern?

    - by mill
    I have the following class: public class UserGroup { public string GroupName { get; set; } public bool IsIntheGroup{ get; set; } } I want to bind an ObservableCollection of UserGroup items to listbox containing checkbox’s for each item in the collection and the checkbox is cheked based on the IsIntheGroup property of the UserGroup. In my ViewModel I made an ObservableCollection of the UserGroup class: public ObservableCollection Groups { get; set; } and loaded its contents (instances of UserGroup) from my database model I used the following code in my view: ListBox ItemsSource="{Binding Groups, ValidatesOnDataErrors=True, UpdateSourceTrigger=PropertyChanged}" ListBox.ItemTemplate DataTemplate StackPanel Orientation="Horizontal" CheckBox IsChecked="{Binding IsIntheGroup, Mode=TwoWay}"/ TextBlock Text="{Binding GroupName}" / /StackPanel /DataTemplate /ListBox.ItemTemplate /ListBox The problem is I am not notified when the user checks/unchecks a check box in the list so my two way binding failed… How do I do a two way binding in such a case?

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  • Saving an active record, in what order are the associated objects saved?

    - by Bryan
    In rails, when saving an active_record object, its associated objects will be saved as well. But has_one and has_many association have different order in saving objects. I have three simplified models: class Team < ActiveRecord::Base has_many :players has_one :coach end class Player < ActiveRecord::Base belongs_to :team validates_presence_of :team_id end class Coach < ActiveRecord::Base belongs_to :team validates_presence_of :team_id end I expected that when team.save is called, team should be saved before its associated coach and players. I use the following code to test these models: t = Team.new team.coach = Coach.new team.save! team.save! returns true. But in another test: t = Team.new team.players << Player.new team.save! team.save! gives the following error: > ActiveRecord::RecordInvalid: > Validation failed: Players is invalid I figured out that team.save! saves objects in the following order: 1) players, 2) team, and 3) coach. This is why I got the error: When a player is saved, team doesn't yet have a id, so validates_presence_of :team_id fails in player. Can someone explain to me why objects are saved in this order? This seems not logical to me.

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  • Which design pattern should be used to create an emulator?

    - by Facon
    I have programmed an emulator, but I have some doubts about how to organizate it properly, because, I see that it has some problems about classes connection (CPU <- Machine Board). For example: I/O ports, interruptions, communication between two or more CPU, etc. I need for the emulator to has the best performance and good understanding of the code. PD: Sorry for my bad English. EDITED - Asking for multiple patterns.

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  • How Do I Remove The First 4 Characters From A String If It Matches A Pattern In Ruby

    - by James
    I have the following string: "h3. My Title Goes Here" I basically want to remove the first 4 characters from the string so that I just get back: "My Title Goes Here". The thing is I am iterating over an array of strings and not all have the h3. part in front so I can't just ditch the first 4 characters blindly. I have checked the docs and the closest think I could find was chomp, but that only works for the end of a string. Right now I am doing this: "h3. My Title Goes Here".reverse.chomp(" .3h").reverse This gives me my desired output, but there has to be a better way right? I mean I don't want to reverse a string twice for no reason. I am new to programming so I might have missed something obvious, but I didn't see the opposite of chomp anywhere in the docs. Is there another method that will work? Thanks!

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  • What's the best practice or design pattern for user registration ?

    - by Space Cracker
    We have a big portal that needs user registration to allow them use its services. It's already done in .NET and SOL Server 2005. we are in the phase now of discovering all the problems of the current registration system to build a new robust flexible one that can be extended easily and can be more usable for all services. Could any help me find best practices and design patterns to help me rebuild this using good architectural practices?

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  • How can I refactor that code ? (state pattern ?)

    - by alex
    Hello guys, How can I refactor that code ? public enum enum1 { value1 = 0x01, value2 = 0x02, value3 = 0x03, value4 = 0x04, value5 = 0x05, UNKNOWN = 0xFF } class class1 { private const string STR_VALUE1 = "some text description of value1"; private const string STR_VALUE2 = "some text description of value2"; private const string STR_VALUE3 = "some text description of value3"; private const string STR_VALUE4 = "some text description of value4"; private const string STR_VALUE5 = "some text description of value5"; private const string STR_VALUE6 = "some text description of unknown type"; public static string GetStringByTypeCode(enum1 type) { switch(type) { case enum1.value1: return STR_VALUE1; case enum1.value2: return STR_VALUE2; case enum1.value3: return STR_VALUE3; case enum1.value4: return STR_VALUE4; case enum1.value5: return STR_VALUE5; default: return STR_VALUE6; } } } PS: there are many enum1...enumX and GetStringByTypeCode(enum1) ... GetStringByTypeCode(enumX) methods.

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  • JPA: what is the proper pattern for iterating over large result sets?

    - by Caffeine Coma
    Let's say I have a table with millions of rows. Using JPA, what's the proper way to iterate over a query against that table, such that I don't have all an in-memory List with millions of objects? I suspect that the following will blow up if the table is large: List<Model> models = entityManager().createQuery("from Model m", Model.class).getResultList(); for (Model model : models) { // do something with model } Is pagination (looping and manually updating setFirstResult()/setMaxResult()) really the best solution?

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  • How to check for an active Internet Connection on iPhone SDK?

    - by Brock Woolf
    I would like to check to see if I have an Internet connection on the iPhone using the Cocoa Touch libraries. I came up with a way to do this using an NSUrl. The way I did it seems a bit unreliable (because even Google could one day be down and relying on a 3rd party seems bad) and while I could check to see for a response from some other websites if Google didn't respond, it does seem wasteful and an unnecessary overhead on my application. - (BOOL) connectedToInternet { NSString *URLString = [NSString stringWithContentsOfURL:[NSURL URLWithString:@"http://www.google.com"]]; return ( URLString != NULL ) ? YES : NO; } Is what I have done bad? (Not to mention 'stringWithContentsOfURL' is deprecated in 3.0) And if so what is a better way to accomplish this?

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  • What design pattern should be used to create an emulator?

    - by Facon
    I have programmed an emulator, but I have some doubts about how to organizate it properly, because, I see that it has some problems about classes connection (CPU <- Machine Board). For example: I/O ports, interruptions, communication between two or more CPU, etc. I need for the emulator to has the best performance and good understanding of the code. PD: Sorry for my bad English.

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  • How do I push `sed` matches to the shell call in the replacement pattern?

    - by rassie
    I need to replace several URLs in a text file with some content dependent on the URL itself. Let's say for simplicity it's the first line of the document at the URL. What I'm trying is this: sed "s/^URL=\(.*\)/TITLE=$(curl -s \1 | head -n 1)/" file.txt This doesn't work, since \1 is not set. However, the shell is getting called. Can I somehow push the sed match variables to that subprocess?

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