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• Visual Studio - How to use an existing vsproj's project settings as a template for new project?

  - by Jakobud

  There is some software I want to write a plugin for. The software includes some sample plugins. I want to create a new fresh project but I want to use one of the sample plugin vsproj's project settings as a template. It doesn't seem very clear on how to do this. If I do "New Project From Existing Code" that only imports the cpp, h, etc files into the new project. Right now the only way I can see to copy a sample projects settings is to open two instances of VS2005 next to each other and simply mimic the settings... Surely there is a built in method of doing this?

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• Is an ArrayList automatically declared static in Java, if it is an instance variable?

  - by Alex

  I'm trying to do something like this: private class aClass { private ArrayList<String> idProd; aClass(ArrayList<String> prd) { this.idProd=new ArrayList<String>(prd); } public ArrayList<String> getIdProd() { return this.idProd; } } So if I have multiple instances of ArrayLIst<String> (st1 ,st2 ,st3) and I want to make new objects of aClass: { aClass obj1,obj2,obj3; obj1=new aClass(st1); obj2=new aClass(st2); obj3=new aClass(st3); } Will all of the aClass objects return st3 if I access the method getIdProd() for each of them(obj1..obj3)? Is an ArrayList as an instance variable automatically declared static?

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• LINQ .Cast() extension method fails but (type)object works.

  - by Ben Robinson

  To convert between some LINQ to SQL objects and DTOs we have created explicit cast operators on the DTOs. That way we can do the following: DTOType MyDTO = (LinqToSQLType)MyLinq2SQLObj; This works well. However when you try to cast using the LINQ .Cast() extension method it trows an invalid cast exception saying cannot cast type Linq2SQLType to type DTOType. i.e. the below does not work List<DTO.Name> Names = dbContact.tNames.Cast<DTO.Name>() .ToList(); But the below works fine: DAL.tName MyDalName = new DAL.tName(); DTO.Name MyDTOName = (DTO.Name)MyDalName; and the below also works fine List<DTO.Name> Names = dbContact.tNames.Select(name => (DTO.Name)name) .ToList(); Why does the .Cast() extension method throw an invalid cast exception? I have used the .Cast() extension method in this way many times in the past and when you are casting something like a base type to a derived type it works fine, but falls over when the object has an explicit cast operator.

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• Is there a way to bring an application's GUI to the current desktop?

  - by Davy8

  Background: Started a fair amount of work before realizing that a Windows Service cannot start an app with a GUI that displays without potential problems. The proper solution of separating the GUI of the app to be started is non-trivial, so I'm trying to think of alternative solutions. There is a GUI to manage the service that is a separate executable, but the process to be launched (actually multiple instances of it) has its own GUI that needs to be shown. It doesn't need to be made visible by the service itself, but it needs to be at least able to be made visible by another process with a visible GUI. The Windows User that is running the service and that needs to see the GUI of the launched process is the same and known at install time. Is there some way to accomplish this or is it back to the drawing board? Also both the service and the app to launch are both our code and modifiable.

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• Is there any reason why someone would want to create an Core Data model programmatically?

  - by mystify

  I wonder in which cases it would be good to make an NSManagedObjectModel completely programmatically, with NSEntityDescription instances and all this stuff. I'm that kind of person who prefers to code programmatically, rejecting Interface Builder. But when it comes to Core Data, I have a hard time figuring out why I should kill my time NOT using the nice Xcode Data Modeler tool. And since data models are stuck to a given state (except when you want to do some ugly migration operations where thinks probably go wrong and users get mad, really mad), I see no big sense in a data model that's made programmatically for the purpose of changing it all the time. Did I miss something?

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• WPF: Template Binding in Control template

  - by Sam

  I have the following control template. I wish to set the source property for the image control in the control template using Template Binding. But since this is a control template for button control and the button control doesn't have source property, i can't use TemplateBinding in this case. <ControlTemplate x:Key="BtnTemplate" TargetType="Button"> <Border CornerRadius="5" Margin="15" Cursor="Hand"> <StackPanel> <Image Name="Img" Style="{StaticResource ImageStyle}" Source="temp.jpg" Height="100" Width="100" Margin="5"></Image> <Label Content="{TemplateBinding Content}" Background="Transparent" Margin="2"></Label> </StackPanel> </Border> </ControlTemplate> Since i have to set different images for different instances of button, i can't hardcode the path as well. Please let me know how to tackle this situation.

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• How to make a daemon which will accept arbitrary commands

  - by Jono

  Right now the program can be launched in a linux terminal. Once running you can type various commands and the program will do stuff on the machine until the user quits. I would like to make the program into a service that the user runs and it goes to the background. Then the user should be able to make commands to it. Like start and stop, and write something to a log and whatever else my program does. Note that I need to send it arbitrary commands that my program will handle, not just start and stop. Maybe this means it is no longer a daemon - I dont know. How do I do this? Also, if this is not too hard, I would like to be able to run multiple instances of this service. But it is not essential.

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• Is an ArrayList automaticaly declared static in Java, if it is an instance variable?

  - by Alex

  I'm trying to do something like this: private class aClass { private ArrayList<String> idProd; aClass(ArrayList<String> prd) { this.idProd=new ArrayList<String>(prd); } public ArrayList<String> getIdProd() { return this.idProd; } } So if I have multiple instances of ArrayLIst<String> (st1 ,st2 ,st3) and I want to make new objects of aClass: { aClass obj1,obj2,obj3; obj1=new aClass(st1); obj2=new aClass(st2); obj3=new aClass(st3); } Will all of the aClass objects return st3 if I access the method getIdProd() for each of them(obj1..obj3)? Is an ArrayList as an instance variable automatically declared static?

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• How to initialise a STL vector/list with a class without invoking the copy constructor

  - by Warpspace

  I have a C++ program that uses a std::list containing instances of a class. If I call e.g. myList.push_back(MyClass(variable)); it goes through the process of creating a temporary variable, and then immediately copies it to the vector, and afterwards deletes the temporary variable. This is not nearly as efficient as I want, and sucks when you need a deep copy. I would love to have the constructor of my class new something and not have to implement a copy constructor just to allocate my memory for the second time and waste runtime. I'd also rather not have to immediately find the class instance from the vector/list and then manually allocate the memory (or do something horrible like allocate the memory in the copy constructor itself). Is there any way around this (I'm not using Visual Studio BTW)?

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• Asynchrous calls cause StaleObjectStateException

  - by Mulone

  Hi all, I'm struggling with a Grails service. The service gets AJAX calls from the clients and behaves like a simple local cache for remote objects: void **someCallFromClient**() { // extract params def results = remoteService.queryService(params) results.each{ // try to fetch result object from local DB def obj = SomeClass.findBySomeField(result.someField) if (!obj){ obj = new Result(params) obj.save() } // do stuff on obj } } The service works fine when only one client is connected, but as soon as 2 or more clients start bombing the server with requests, I start getting: 2010-05-24 13:09:49,764 [30893094@qtp-26315919-2] ERROR errors.GrailsExceptionResolver - Row was updated or deleted by another transaction (or unsaved-value mapping was incorrect): [ some object #892901] org.hibernate.StaleObjectStateException: Row was updated or deleted by another transaction (or unsaved-value mapping was incorrect): [ some object #892901] // very long stactrace It probably happens when 2 calls are trying to create the same object concurrently. I suppose this is a rather typical situation to end up in. Could you recommend any pattern/good practice to fix this issue? For example, is there a way to say to one of the service instances to hang on and wait for the other to finish its stuff and try again? Cheers!

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• Does "delegate" mean a type or an object?

  - by Michal Czardybon

  Reading from MSDN: "A delegate is a type that references a method. Once a delegate is assigned a method, it behaves exactly like that method." Does then "delegate" mean a type or an object?! ...It cannot be both. It seems to me that the single word is used in two different meanings: a type containing a reference to a method of some specified signature, an object of that type, which can be actually called like a method. I would prefer a more precise vocabulary and use "delegate type" for the first case. I have been recently reading a lot about events and delegates and that ambiguity was making me confused many times. Some other uses of "delegate" word in MSDN in the first meaning: "Custom event delegates are needed only when an event generates event data" "A delegate declaration defines a class that is derived from the class System.Delegate" Some other uses of "delegate" word in MSDN in the second meaning: "specify a delegate that will be called upon the occurrence of some event" "Delegates are objects that refer to methods. They are sometimes described as type-safe function pointers" What do you think? Why did people from Microsoft introduced this ambiguity? Am I the only person to have conceptual problems with different notions being referenced with the same word.

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• Code Golf: Duplicate Character Removal in String

  - by Alex

  The challenge: The shortest code, by character count, that detects and removes duplicate characters in a String. Removal includes ALL instances of the duplicated character (so if you find 3 n's, all three have to go), and original character order needs to be preserved. Example Input 1: nbHHkRvrXbvkn Example Output 1: RrX Example Input 2: nbHHkRbvnrXbvkn Example Output 2: RrX (the second example removes letters that occur three times; some solutions have failed to account for this) (This is based on my other question where I needed the fastest way to do this in C#, but I think it makes good Code Golf across languages.)

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• Can I override spring beans instatiated with component scanning?

  - by Pablojim

  If I use component scanning in Spring 2.5 but then also define a controller in xml. Do I get two instances of this bean in my application context? If so which instance will be called for its related RequestMappings? <bean id="myController" class="domain.MyController"> <property name="filters"> <list> <ref local="filter1"/> <ref local="filter2"/> </list> </property> </bean>

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• How to pass data to a C++0x lambda function that will run in a different thread?

  - by Dimitri C.

  In our company we've written a library function to call a function asynchronously in a separate thread. It works using a combination of inheritance and template magic. The client code looks as follows: DemoThread thread; std::string stringToPassByValue = "The string to pass by value"; AsyncCall(thread, &DemoThread::SomeFunction, stringToPassByValue); Since the introduction of lambda functions I'd like to use it in combination with lambda functions. I'd like to write the following client code: DemoThread thread; std::string stringToPassByValue = "The string to pass by value"; AsyncCall(thread, [=]() { const std::string someCopy = stringToPassByValue; }); Now, with the Visual C++ 2010 this code doesn't work. What happens is that the stringToPassByValue is not copied. Instead the "capture by value" feature passes the data by reference. The result is that if the function is executed after stringToPassByValue has gone out of scope, the application crashes as its destructor is called already. So I wonder: is it possible to pass data to a lambda function as a copy? Note: One possible solution would be to modify our framework to pass the data in the lambda parameter declaration list, as follows: DemoThread thread; std::string stringToPassByValue = "The string to pass by value"; AsyncCall(thread, [=](const std::string stringPassedByValue) { const std::string someCopy = stringPassedByValue; } , stringToPassByValue); However, this solution is so verbose that our original function pointer solution is both shorter and easier to read. Update: The full implementation of AsyncCall is too big to post here. In short, what happens is that the AsyncCall template function instantiates a template class holding the lambda function. This class is derived from a base class that contains a virtual Execute() function, and upon an AsyncCall() call, the function call class is put on a call queue. A different thread then executes the queued calls by calling the virtual Execute() function, which is polymorphically dispatched to the template class which then executes the lambda function.

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• Are there any tools to optimize the number of consumer and producer threads on a JMS queue?

  - by lindelof

  I'm working on an application that is distributed over two JBoss instances and that produces/consumes JMS messages on several JMS queues. When we configured the application we had to determine which threading model we would use, in particular the number of producing and consuming threads per queue. We have done this in a rather ad-hoc fashion but after reading the most recent columns by Herb Sutter in Dr Dobbs (in particular this one) I would like to size our threads in a more rigorous manner. Are there any methods/tools to measure the throughput of JMS queues (in particular JBoss Messaging queues) as a function of the number of producing/consuming threads?

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• How efficient is an if statement compared to a test that doesn't use an if? (C++)

  - by Keand64

  I need a program to get the smaller of two numbers, and I'm wondering if using a standard "if x is less than y" int a, b, low; if (a < b) low = a; else low = a; is more or less efficient than this: int a, b, low; low = b + ((a - b) & ((a - b) >> 31)); (or the variation of putting int delta = a - b at the top and rerplacing instances of a - b with that). I'm just wondering which one of these would be more efficient (or if the difference is to miniscule to be relevant), and the efficiency of if-else statements versus alternatives in general.

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• JOIN (SELECT DISTINCT [..] substitute

  - by FRKT

  Hello, I'd like to find a substitute for using SELECT DISTINCT in a derived table. Let's say I have three tables: CREATE TABLE `trades` ( `tradeID` int(11) unsigned NOT NULL AUTO_INCREMENT, `employeeID` int(11) unsigned NOT NULL, `corporationID` int(11) unsigned NOT NULL, `profit` int(11) NOT NULL, KEY `tradeID` (`tradeID`), KEY `employeeID` (`employeeID`), KEY `corporationID` (`corporationID`) ) ENGINE=MyISAM DEFAULT CHARSET=latin1 CREATE TABLE `corporations` ( `corporationID` int(11) unsigned NOT NULL AUTO_INCREMENT, `name` varchar(255) NOT NULL, PRIMARY KEY (`corporationID`) ) ENGINE=MyISAM DEFAULT CHARSET=latin1 CREATE TABLE `employees` ( `employeeID` int(11) unsigned NOT NULL AUTO_INCREMENT, `name` varchar(255) NOT NULL, PRIMARY KEY (`employeeID`) ) ENGINE=MyISAM DEFAULT CHARSET=latin1 Let's say I'd like to find out how much profit a specific employee has generated. Simple: SELECT SUM(profit) FROM trades JOIN employees ON trades.employeeID = employees.employeeID AND employees.employeeID = 1; It gets trickier if I'd like to query how much revenue a specific corporation has, however. I cannot simply replicate the aforementioned query, because two or more employees from the same company might be involved in the same trade. This query should do the trick: SELECT SUM(profit) FROM trades JOIN (SELECT DISTINCT tradeID FROM trades WHERE trades.corporationID = 1) ... unfortunately, DISTINCT JOINs seem crazy ineffective. Is there any alternative I can use to determine how much revenue a corporation has, taking into account that a corporation might be listed several times with the same tradeID?

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• Is the C++ compiler optimizer allowed to break my destructor ability to be called multiple times?

  - by sharptooth

  We once had an interview with a very experienced C++ developer who couldn't answer the following question: is it necessary to call the base class destructor from the derived class destructor in C++? Obviously the answer is no, C++ will call the base class destructor automagically anyway. But what if we attempt to do the call? As I see it the result will depend on whether the base class destructor can be called twice without invoking erroneous behavior. For example in this case: class BaseSafe { public: ~BaseSafe() { } private: int data; }; class DerivedSafe { public: ~DerivedSafe() { BaseSafe::~BaseSafe(); } }; everything will be fine - the BaseSafe destructor can be called twice safely and the program will run allright. But in this case: class BaseUnsafe { public: BaseUnsafe() { buffer = new char[100]; } ~BaseUnsafe () { delete[] buffer; } private: char* buffer; }; class DerivedUnsafe { public: ~DerivedUnsafe () { BaseUnsafe::~BaseUnsafe(); } }; the explicic call will run fine, but then the implicit (automagic) call to the destructor will trigger double-delete and undefined behavior. Looks like it is easy to avoid the UB in the second case. Just set buffer to null pointer after delete[]. But will this help? I mean the destructor is expected to only be run once on a fully constructed object, so the optimizer could decide that setting buffer to null pointer makes no sense and eliminate that code exposing the program to double-delete. Is the compiler allowed to do that?

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• The most efficient way to calculate an integral in a dataset range

  - by Annalisa

  I have an array of 10 rows by 20 columns. Each columns corresponds to a data set that cannot be fitted with any sort of continuous mathematical function (it's a series of numbers derived experimentally). I would like to calculate the integral of each column between row 4 and row 8, then store the obtained result in a new array (20 rows x 1 column). I have tried using different scipy.integrate modules (e.g. quad, trpz,...). The problem is that, from what I understand, scipy.integrate must be applied to functions, and I am not sure how to convert each column of my initial array into a function. As an alternative, I thought of calculating the average of each column between row 4 and row 8, then multiply this number by 4 (i.e. 8-4=4, the x-interval) and then store this into my final 20x1 array. The problem is...ehm...that I don't know how to calculate the average over a given range. The question I am asking are: Which method is more efficient/straightforward? Can integrals be calculated over a data set like the one that I have described? How do I calculate the average over a range of rows?

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• Getting empty update rectangle in OnPaint after calling InvalidateRect on a layered window

  - by Shawn

  I'm trying to figure out why I've been getting an empty update rectangle when I call InvalidateRect on a transparent window. The idea is that I've drawn something on the window (it gets temporarily switched to have an alpha of 1/255 for the drawing), and then I switch it to full transparent mode (i.e. alpha of 0) in order to interact with the desktop & to be able to move the drawing around the screen on top of the desktop. When I try to move the drawing, I get its bounding rectangle & use it to call InvalidateRect, as such: InvalidateRect(m_hTarget, &winRect, FALSE); I've confirmed that the winRect is indeed correct, and that m_hTarget is the correct window & that its rectangle fully encompasses winRect. I get into the OnPaint handler in the class corresponding to m_hTarget, which is derived from a CWnd. In there, I create a CPaintDC, but when I try to access the update rectangle (dcPaint.m_ps.rcPaint) it's always empty. This rectangle gets passed to a function that determines if we need to update the screen (by using UpdateLayeredWindow in the case of a transparent window). If I hard-code a non-empty rectangle in here, the remaining code works correctly & I am able to move the drawing around the screen. I tried changing the 'FALSE' parameter to 'TRUE' in InvalidateRect, with no effect. I also tried using a standard CDC, and then using BeginPaint/EndPaint method in my OnPaint handler, just to ensure that CPaintDC wasn't doing something odd ... but I got the same results. The code that I'm using was originally designed for opaque windows. If m_hTarget corresponds to an opaque window, the same set of function calls results in the correct (i.e. non-empty) rectangle being passed to OnPaint. Once the window is layered, though, it doesn't seem to work right.

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• Custom constructors for models in Google App Engine (python)

  - by Nikhil Chelliah

  I'm getting back to programming for Google App Engine and I've found, in old, unused code, instances in which I wrote constructors for models. It seems like a good idea, but there's no mention of it online and I can't test to see if it works. Here's a contrived example, with no error-checking, etc.: class Dog(db.Model): name = db.StringProperty(required=True) breeds = db.StringListProperty() age = db.IntegerProperty(default=0) def __init__(self, name, breed_list, **kwargs): db.Model.__init__(**kwargs) self.name = name self.breeds = breed_list.split() rufus = Dog('Rufus', 'spaniel terrier labrador') rufus.put() The **kwargs are passed on to the Model constructor in case the model is constructed with a specified parent or key_name, or in case other properties (like age) are specified. This constructor differs from the default in that it requires that a name and breed_list be specified (although it can't ensure that they're strings), and it parses breed_list in a way that the default constructor could not. Is this a legitimate form of instantiation, or should I just use functions or static/class methods? And if it works, why aren't custom constructors used more often?

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• jpa join query on a subclass

  - by Brian

  I have the following relationships in JPA (hibernate). Object X has two subclasses, Y and Z. Object A has a manyToOne relationship to object X. (Note, this is a one-sided relationship so object X cannot see object A). Now, I want to get the max value of a column in object A, but only where the relationship is of a specific subtype, ie...Y. So, that equates to...get the max value of column1 in object A, across all instances of A where they have a relationship with Y. Is this possible? I'm a bit lost as how to query it. I was thinking of something like: String query = "SELECT MAX(a.columnName) FROM A a join a.x; Query query = super.entityManager.createQuery(query); query.execute(); However that doesn't take account of the subclass of X...so I'm a bit lost. Any help would be much appreciated.

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• Sharepoint publishing cache- counter missing on WFE(Object Caching)

  - by Ryan

  I want to tune object caching in my sharepoint environment. The way to do is check sharepoint publishing cache counter through perfmon on your farm. I have one application server and 2 WFE but when I am trying to create counter for my WFE its showing Sharepoint publishing cache but I am not able to add any instance of it but when I select my application server I can see all the instances. But If I want to check publishing hit ratio i need to run this on WFE also ...correct me if I m wrong? How to resolve this issue? Also, how to check the hit ratio as our site is not go-live so we don't get enuf users to hit the site to check this thing. Does it means that I can tune it up only my site go live and real load will get on it. Thanks, Amit

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• Referencing text input fields in CKEditor dialogs

  - by rt-uk

  Hi, I've been playing around with this for a couple of weeks now with no success... In a CKEditor dialog, text input fields are renamed with a unique number - e.g. id: 'txtUrl' will become something like id='27_textinput'. How do I reference this? // I feel it should be something like: var myfield = CKEDITOR.instances.myElement.document.$.body.getId('txtUrl'); // or maybe: var myfield = CKEDITOR.dialog.getContentElement('info','txtUrl'); // and then: myfield.value = 'myvalue'; But these don't work. Please help! Thanks in advance, R

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• Singletons vs. Application Context in Android?

  - by mschonaker

  Recalling this post enumerating several problems of using singletons and having seen several examples of Android applications using singleton pattern, I wonder if it's a good idea to use Singletons instead of single instances shared through global application state (subclassing android.os.Application and obtaining it through context.getApplication()). What advantages/drawbacks would have both mechanisms? To be honest, I expect the same answer in this post http://stackoverflow.com/questions/2709071/singleton-pattern-with-web-application-not-a-good-idea but applied to Android. Am I correct? What's different in DalvikVM otherwise? EDIT: I would like to have opinions on several aspects involved: Synchronization Reusability Testing Thanks in advance.

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