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  • Coordinating typedefs and structs in std::multiset (C++)

    - by Sarah
    I'm not a professional programmer, so please don't hesitate to state the obvious. My goal is to use a std::multiset container (typedef EventMultiSet) called currentEvents to organize a list of structs, of type Event, and to have members of class Host occasionally add new Event structs to currentEvents. The structs are supposed to be sorted by one of their members, time. I am not sure how much of what I am trying to do is legal; the g++ compiler reports (in "Host.h") "error: 'EventMultiSet' has not been declared." Here's what I'm doing: // Event.h struct Event { public: bool operator < ( const Event & rhs ) const { return ( time < rhs.time ); } double time; int eventID; int hostID; }; // Host.h ... void calcLifeHist( double, EventMultiSet * ); // produces compiler error ... void addEvent( double, int, int, EventMultiSet * ); // produces compiler error // Host.cpp #include "Event.h" ... // main.cpp #include "Event.h" ... typedef std::multiset< Event, std::less< Event > > EventMultiSet; EventMultiSet currentEvents; EventMultiSet * cePtr = &currentEvents; ... Major questions Where should I include the EventMultiSet typedef? Are my EventMultiSet pointers obviously problematic? Is the compare function within my Event struct (in theory) okay? Thank you very much in advance.

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  • Ubuntu + virtualenv = a mess? virtualenv hates dist-packages, wants site-packages

    - by lostincode
    Can someone please explain to me what is going on with python in ubuntu 9.04? I'm trying to spin up virtualenv, and the --no-site-packages flag seems to do nothing with ubuntu. I installed virtualenv 1.3.3 with easy_install (which I've upgraded to setuptools 0.6c9) and everything seems to be installed to /usr/local/lib/python2.6/dist-packages I assume that when installing a package using apt-get, it's placed in /usr/lib/python2.6/dist-packages/ ? The issue is, there is a /usr/local/lib/python2.6/site-packages as well that just sits there being empty. It would seem (by looking at the path in a virtualenv) that this is the folder virtualenv uses as backup. Thus even thought I omit --no-site-packages, I cant access my local systems packages from any of my virtualenv's. So my questions are: How do I get virtualenv to point to one of the dist-packages? Which dist-packages should I point it to? /usr/lib/python2.6/dist-packages or /usr/local/lib/python2.6/dist-packages/ What is the point of /usr/lib/python2.6/site-packages? There's nothing in there! Is it first come first serve on the path? If I have a newer version of package XYZ installed in /usr/local/lib/python2.6/dist-packages/ and and older one (from ubuntu repos/apt-get) in /usr/lib/python2.6/dist-packages, which one gets imported when I import xyz? I'm assuming this is based on the path list, yes? Why the hell is this so confusing? Is there something I'm missing here? Where is it defined that easy_install should install to /usr/local/lib/python2.6/dist-packages? Will this affect pip as well? Thanks to anyone who can clear this up!

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  • Queuing using table or MSMQ?

    - by Lieven Cardoen
    A part of the application I'm working on is an swf that shows a test with some 80 questions. Each question is saved to a sql server through WebORB and asp.net. If a candidate finisheds the test, the session needs to be validated. Problem now is that sometimes 350 candidates finish their test at the same moment, and cpu on webserver and sql server explodes (350 validations concurrently). Now, how would I implement queuing here? In the database, there's a table that has a record for each session. One column holds the status. 1 is finished, 2 is validated. I could implement queuing in two ways (as I see it, maybe you have other propositions): A process that checks the table for records with status 1. If it finds one, it validates the session. So, sessions are validated one after one. If a candidate finishes its session, a message is sent to a MSMQ queue. Another process listens to the queue and validates sessions one after one. Now, What would be the best approach? Where do you start the process that will validate sessions? In your global.asax (application_start)? As a windows service? As an exe on the root of the website that is started in application_start? To me, using the table and looking for records with status 1 seems the easiest way.

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  • WCF - "Encountered unexpected character 'c'."

    - by Villager
    Hello, I am trying to do something that I thought would be simple. I need to create a WCF service that I can post to via JQuery. I have an operation in my WCF service that is defined as follows: [OperationContract] [WebInvoke(Method = "POST", BodyStyle = WebMessageBodyStyle.WrappedRequest, RequestFormat=WebMessageFormat.Json, ResponseFormat=WebMessageFormat.Json)] public string SendMessage(string message, int urgency) { try { // Do stuff return "1"; // 1 represents success } catch (Exception) { return "0"; } } I then try to access this operation from an ASP.NET page via JQuery. My JQuery code to access this operation looks like the following: function sendMessage(message) { $.ajax({ url: "/resources/services/myService.svc/SendMessage", type: "POST", contentType: "application/json; charset=utf-8", data: ({ message: message, urgency: '1' }), dataType: "json", success: function (data) { alert("here!"); }, error: function (req, msg, obj) { alert("error: " + req.responseText); } }); } When I execute this script, the error handler is tripped. In it, I receive an error that says: "Encountered unexpected character 'c'." This message is included with a long stack trace. My question is, what am I doing wrong? I have received other posts such as this one (http://stackoverflow.com/questions/320291/how-to-post-an-array-of-complex-objects-with-json-jquery-to-asp-net-mvc-controll) without any luck. How do I get this basic interaction working? Thank you!

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  • Java-Hibernate: How can I translate these tables to hibernate annotations?

    - by penas
    I need to create a simple application using these tables: http://stackoverflow.com/questions/2612848/are-these-tables-respect-the-3nf-database-normalization I have created the application using simple old JDBC, but I would like to see how the application would look like using Hibernate, but I don't know how to put the sql code in java. I have found LOTS of examples, but I'm pretty much confused about using Hibernate and I don't know If I made such a good joob. For example, for the first three tables: AUTHOR table * Author_ID, PK * First_Name * Last_Name TITLES table * TITLE_ID, PK * NAME * Author_ID, FK DOMAIN table * DOMAIN_ID, PK * NAME * TITLE_ID, FK The code in java: Table 1 @Entity @Table(name = "AUTHORS", schema = "LIBRARY") public class Author{ @Id @GeneratedValue(strategy = GenerationType.AUTO) @Column(name = "Author_ID") private int authorId; @Column(name = "First_Name", nullable = false, length = 50) private String firstName; @Column(name = "Last_Name", nullable = false, length = 40) private String lastName; @OneToMany @JoinColumn(name = "Title_ID") private List<Title> titles; Table 2 @Entity @Table(name = "TITLES") public class Title{ @Id @Column(name = "Title_ID") private int titleID; @Column(name = "Name", nullable = false, length = 50) private String name; @ManyToOne @JoinColumn(name = "Domain_ID") private Domain domains; Table 3 @Entity @Table(name = "DOMAINS") public class Domain{ @Id @GeneratedValue(strategy = GenerationType.AUTO) @Column(name = "Domain_ID") private int Domain_ID; @Column(name = "Name", nullable = false, length = 50) private String name; @OneToOne(mappedBy = "domains") private Title title; } Any good? :)

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  • XSLT, worth investing time in, any actual alternatives?

    - by Keeno
    I realise this has been a few other questions on this topic, and people are saying use your language of choice to manipulate the xml etc etc however, not quite fit my question exactly. Firstly, the scope of the project: We want to develop platform independant e-learning, currently, its a bunch of HTML pages but as they grow and develop they become hard to maintain. The idea: Generate up an XML file + Schema, then produce some XSLT files that process the XML into the eLearning modiles. XML to HTML via XSLT. Why: We would like the flexibily to be able to easy reformat the content (i realise CSS is a viable alternative here) If we decide to alter the pages layout or functionality in anyway, im guessing altering the "shared" XSLT files would be easier than updating the HTML files. So far, we have about 30 modules, with up to 10-30 pages each Depending on some "parameters" we could output drastically different page layouts/structures, above and beyond what CSS can do Now, all this has to be platform independant, and to be able to run "offline" i.e. without a server powering the HTML Negatives ive read so far for XSLT: Overheard? Not exactly sure why...is it the compute power need to convert to HTML? Difficult to learn Better alternatives Now, what I would like to know exactly is: are there actually any viable alternatives for this "offline"? Am I going about it in the correct manner, do you guys have any advice or alternatives. Thanks!

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  • Dealing With Java Default Level Access Specifiers

    - by Tom Tresansky
    I've seen some code in a project recently where some fields in a couple classes have been using the default access modifier without good reason to. It almost looks like a case of "oops, forgot to make these private". Since the classes are used almost exclusively outside of the package they are defined in, the fields are not visible from the calling code, and are treated as private. So the mistake/oversight would not be very noticeable. However, encapsulation is broken. If I wanted to add a new class to the existing package, I could then mess with internal data in objects using fields with default access. So, my questions: Are there any best practices concerning default access specifiers that I should be aware of? Anything that would help prevent this type of accident from re-occurring? Are are any annotations which might say something to the effect of "I really meant for these to be default access"? Using CheckStyle, or any other Eclipse plugins, is there any way to flag instances of default fields, or disallow any not accompanied by, say, a "//default access" comment trailing them?

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  • Resource placement (optimal strategy)

    - by blackened
    I know that this is not exactly the right place to ask this question, but maybe a wise guy comes across and has the solution. I'm trying to write a computer game and I need an algorithm to solve this question: The game is played between 2 players. Each side has 1.000 dollars. There are three "boxes" and each player writes down the amount of money he is going to place into those boxes. Then these amounts are compared. Whoever placed more money in a box scores 1 point (if draw half point each). Whoever scores more points wins his opponents 1.000 dollars. Example game: Player A: [500, 500, 0] Player B: [333, 333, 334] Player A wins because he won Box A and Box B (but lost Box C). Question: What is the optimal strategy to place the money? I have more questions to ask (algorithm related, not math related) but I need to know the answer to this one first. Update (1): After some more research I've learned that these type of problems/games are called Colonel Blotto Games. I did my best and found few (highly technical) documents on the subject. Cutting it short, the problem I have (as described above) is called simple Blotto Game (only three battlefields with symmetric resources). The difficult ones are the ones with, say, 10+ battle fields with non-symmetric resources. All the documents I've read say that the simple Blotto game is easy to solve. The thing is, none of them actually say what that "easy" solution is.

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  • How to implement Administrator rights in Java Application?

    - by Yatendra Goel
    I am developing a Data Modeling Software that is implemented in Java. This application converts the textual data (stored in a database) to graphical form so that users can interpret the data in a more efficient form. Now, this application will be accessed by 3 kinds of persons: 1. Managers (who can fill the database with data and they can also view the visual form of the data after entering the data into the database) 2. Viewers (who can only view the visual form of data that has been filled by managers) 3. Administrators (who can create and manage other administrators, managers and viewers) Now, how to implement 3 diff. views of the same application. Note: Managers, Viewers and Administrators can be located in any part of the world and should access the application through internet. One idea that came in my mind is as follows: Step1: Code all the business logic in EJBs so that it can be used in distributed environment (means which can be accessed by several users through internet) Step2: Code 3 Swing GUI Clients: One for administrators, one for managers and one for viewers. These 3 GUI clients can access business logic written in EJBs. Step3: Distribute the clients corresponding to their users. For instance, manager client to managers. =================================QUESTIONS======================================= Q1. Is the above approach is correct? Q2. This is very common functionality that various softwares have. So, Do they implement this kind of functionality through this way or any other way? Q3. If any other approach would be more better, then what is that approach?

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  • Basic problems (type inference or something else?) in Objective-C/Cocoa.

    - by Matt
    Hi, Apologies for how basic these questions are to some. Just started learning Cocoa, working through Hillegass' book, and am trying to write my first program (a GUI Cocoa app that counts the number of characters in a string). I tried this: NSString *string = [textField stringValue]; NSUInteger *stringLength = [string length]; NSString *countString = (@"There are %u characters",stringLength); [label setStringValue:countString]; But I'm getting errors like: Incompatible pointer conversion initializing 'NSUInteger' (aka 'unsigned long'), expected 'NSUInteger *'[-pedantic] for the first line, and this for the second line: Incompatible pointer types initializing 'NSUInteger *', expected 'NSString *' [-pedantic] I did try this first, but it didn't work either: [label setStringValue:[NSString stringWithFormat:@"There are %u characters",[[textField stringValue] length]]] On a similar note, I've only written in easy scripting languages before now, and I'm not sure when I should be allocing/initing objects and when I shouldn't. For example, when is it okay to do this: NSString *myString = @"foo"; or int *length = 5; instead of this: NSString *myString = [[NSString alloc] initWithString:"foo"]; And which ones should I be putting into the header files? I did check Apple's documentation, and CocoaDev, and the book I'm working for but without luck. Maybe I'm looking in the wrong places.. Thanks to anyone who takes the time to reply this: it's appreciated, and thanks for being patient with a beginner. We all start somewhere. EDIT Okay, I tried the following again: [label setStringValue:[NSString stringWithFormat:@"There are %u characters",[[textField stringValue] length]]] And it actually worked this time. Not sure why it didn't the first time, though I think I might have typed %d instead of %u by mistake. However I still don't understand why the code I posted at the top of my original post doesn't work, and I have no idea what the errors mean, and I'd very much like to know because it seems like I'm missing something important there.

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  • Inheritance and type parameters of Traversable

    - by Jesper
    I'm studying the source code of the Scala 2.8 collection classes. I have questions about the hierarchy of scala.collection.Traversable. Look at the following declarations: package scala.collection trait Traversable[+A] extends TraversableLike[A, Traversable[A]] with GenericTraversableTemplate[A, Traversable] trait TraversableLike[+A, +Repr] extends HasNewBuilder[A, Repr] with TraversableOnce[A] package scala.collection.generic trait HasNewBuilder[+A, +Repr] trait GenericTraversableTemplate[+A, +CC[X] <: Traversable[X]] extends HasNewBuilder[A, CC[A] @uncheckedVariance] Question: Why does Traversable extend GenericTraversableTemplate with type parameters [A, Traversable] - why not [A, Traversable[A]]? I tried some experimenting with a small program with the same structure and got a strange error message when I tried to change it to Traversable[A]: error: Traversable[A] takes no type parameters, expected: one I guess that the use of the @uncheckedVariance annotation in GenericTraversableTemplate also has to do with this? (That seems like a kind of potentially unsafe hack to force things to work...). Question: When you look at the hierarchy, you see that Traversable inherits HasNewBuilder twice (once via TraversableLike and once via GenericTraversableTemplate), but with slightly different type parameters. How does this work exactly? Why don't the different type parameters cause an error?

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  • how to keep the height of the div equal to the union of the height of elements inside it

    - by Idlecool
    I have been making a wordpress template. i got stuck at some place... the problem is, how to maintain the size of a div = the size of p tags and img tags... i have seen that the div only able to contain the p tag but the img tag over flows... i have my code in this following order: <div> <p> some contents <img src="an_image"/> some morecontent</p> <div> what i basically want is: div height = <p> height U(union) <img> height but, what actually i am getting is: div height = <p> height; while <img> over flows i have already checked for similar questions on Stack Overflow but was not able to find one which solves a similar problem.. please give me some idea..

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  • Maven + SSDM Build and Runtime Environment Automation

    - by Randy
    Preface: My Company, like most, has several run-time environments and several release versions which themselves are composed of different versions of various jars. For example, let us consider release versions 1.1, 1.2, and 1.3 of Software X, which may be deployed to a developer computer, testing, or production. Software-x-1.1 is itself composed of jarA-0.9.1 and jarB-0.7.5, but software-x-1.3 is composed of jarA-1.7.31 and jarB-0.8.1. Currently we use Spring's PropertyPlaceholderConfigurer to configure run-time variables (such as database credentials), however, properties also change with release versions. We also use Maven 2 POM version 4 to specify which versions of our code need to be used. We place the version numbers of our jars as properties within profiles (dev,test,prod) inside of the parent pom and then reference those version numbers in all project poms. As of right now, we have no way to specify which project versions pertain to a given release other than the most current one. Moreover, we deploy our run-time configurations to the SSDM pickup which then configures and creates the services defined by the built versions of our software. -- Questions: Is there any procedure/tool we can use to build our product by merely providing the run-time environment and version number? IE "build 1.1 dev"? Is there anyway we can store the required jar versions for each release build? We are currently versioning all files, including the parent pom, but merely versioning the parent pom does not record which release version is pertinent to that parent pom. What else can we do to further automate the process of builds? For example, if we could manage run-time configurations within the parent pom that would be a step in the right direction, but that seems like a violation of scope. Any tool outside of our framework is inconceivable at this point, but not in the far future. Summary: How can we automate our build process to the fullest extent without being error prone?

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  • hosting a high traffic facebook app (game)

    - by z3cko
    we are currently developing a high traffic facebook application. all the traffic will be within one month, where there are 500.000 to 1.000.000 expected users. after that month, the game is over and we have a winner - so the app will be archived. we are currently planning to develop the application with ruby on rails and searching for hosting options that can deal with the traffic. the problem is not so much the users, but the peak values: we will have around 500.000 requests coming daily within a short timeframe (lets say within 3 minutes in the worst case) we are expecting 500.000 to 1.000.000 users of the application, with peaks at 1:00pm (timezone GMT+1), where most (up to 80% of the users) will send most of the requests. the requests are from 11th of june to 11.july - after that, the app/game is closed/over. we are currently developing an aggressive caching mechanism - currently we are thinking about 2 or 3 small apps/webservices, that will handle the load. the load is distributed as follows: a) main application, cached data (11 screens, 200k each) b) voting: every day until 1:00pm (timezone GMT+1) - every user votes with about 10k data sent, high concurrent peak values! questions: is there any specific application setup that is recommendable? are there any hosting partners that can be recommended? thanks!

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  • Outstanding issues with jQuery.ajax() in IE8?

    - by RyanV
    I am loading feed-items into a ul using this jQuery .ajax() call, which I basically lifted from http://www.makemineatriple.com/2007/10/bbcnewsticker/ var timestamp = true; //set whether timestamp is displayed in $.ajax({ type: "GET", url: "sample-feed.xml", dataType: "xml", success: function(xml) { $(xml).find('item').each(function(){ var title = $(this).find('title').text(); var link = $(this).find('link').text(); if(title.length >=57){ title = title.substring(0,54) + "..."; } var addItem = '<li class="tickerTitle"><a href="'+link+'">'+title+'</a>'; if (Boolean(timestamp)== true){ var time = new Date(Date.parse($(this).find('pubDate').text())); addItem +='<span class="timestamp">' + makestamp(time) +'</span></li>'; } $('ul#news').append(addItem); }); It works in Chrome 4 and Firefox 3.6, but I load it up in IE8 and somehow the ajax call fails. I have tried to use IE8's Developer tools to see where exactly it fails, but I haven't been successful yet. So two questions Is there anything blatantly wrong with my ajax call here that could be preventing me from seeing it in IE where it works in FF/Chrome? Are there any special considerations I have to make for the Internet Explorer family of browsers with regards to this particular jQuery method? I've done some googling on this but nothing obvious is coming up. One other note: I am currently using jQuery 1.3.2 due to some legacy scripts on the same site. I did try loading 1.4.2 and it had the same results on IE8

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  • Sync two SqlExpress using NHibernate

    - by Christian
    Hello, I am creating a simple project management system which uses NHibernate for object storage. The underlying database is SQL express (at least currently for development). The client runs on either the desktop or laptop. I know I could use web-services and store the DB only on the desktop, but this would force the desktop to be available all the time. I am currently thinking about duplicating the DB, having two instances with "different data". To clarify, we are not talking about a productive app here, its a prototype. One way to achieve this very simple would be the following process: Client: Check if desktop DB is available (through web service) Client: If yes, use desktop storage, no problem here Client: If not, use own DB as storage Client: Poll desktop regulary, as soon as it comes on, sync Client: Switch to desktop storage ... Desktop: Do not attempt any DB operation before checking for required sync Desktop: If sync needed, do it... My question is now, how would you sync? Assume 4 or 5 types of objects, all have GUID as identifiers. Would you always manually "lazy load" all objects of a certain type and feed them to the DB. Would you always drop the whole desktop DB in case the client DB may be newer and out of sync? Again, I want to stress out, I am not assuming any conflicts or stale data, I basically just want to "copy the whole DB from the client". Would you use NHibernate for this? Or would you separate the copy process? When I think about it, my questions comes down to this: Is there any function from NHibernate: SyncDBs_SourceWins_(SourceDB, TargetDB) Thanks for help, Chris

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  • C++: defining maximum/minimum limits for a class

    - by Luis
    Basically what the title says... I have created a class that models time slots in a variable-granularity daily schedule (where for example the first time slot is 30 minutes, but the second time slot can be 40 minutes); the first available slot starts at (a value comparable to) 1. What I want to do now is to define somehow the maximum and minimum allowable values that this class takes and I have two practical questions in order to do so: 1.- does it make sense to define absolute minimum and maximum in such a way for a custom class? Or better, does it suffice that a value always compares as lower-than any other possible value of the type, given the class's defined relational operators, to be defined the min? (and analogusly for the max) 2.- assuming the previous question has an answer modeled after "yes" (or "yes but ..."), how do I define such max/min? I know that there is std::numeric_limits<> but from what I read it is intended for "numeric types". Do I interpret that as meaning "represented as a number" or can I make a broader assumption like "represented with numbers" or "having a correspondence to integers"? After all, it would make sense to define the minimum and maximum for a date class, and maybe for a dictionary class, but numeric_limits may not be intended for those uses (I don't have much experience with it). Plus, numeric_limits has a lot of extra members and information that I don't know what to make with. If I don't use numeric_limits, what other well-known / widely-used mechanism does C++ offer to indicate the available range of values for a class?

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  • Scala: Correcting type inference of representation type over if statement

    - by drhagen
    This is a follow-up to two questions on representation types, which are type parameters of a trait designed to represent the type underlying a bounded type member (or something like that). I've had success creating instances of classes, e.g ConcreteGarage, that have instances cars of bounded type members CarType. trait Garage { type CarType <: Car[CarType] def cars: Seq[CarType] def copy(cars: Seq[CarType]): Garage def refuel(car: CarType, fuel: CarType#FuelType): Garage = copy( cars.map { case `car` => car.refuel(fuel) case other => other }) } class ConcreteGarage[C <: Car[C]](val cars: Seq[C]) extends Garage { type CarType = C def copy(cars: Seq[C]) = new ConcreteGarage(cars) } trait Car[C <: Car[C]] { type FuelType <: Fuel def fuel: FuelType def copy(fuel: C#FuelType): C def refuel(fuel: C#FuelType): C = copy(fuel) } class Ferrari(val fuel: Benzin) extends Car[Ferrari] { type FuelType = Benzin def copy(fuel: Benzin) = new Ferrari(fuel) } class Mustang(val fuel: Benzin) extends Car[Mustang] { type FuelType = Benzin def copy(fuel: Benzin) = new Mustang(fuel) } trait Fuel case class Benzin() extends Fuel I can easily create instances of Cars like Ferraris and Mustangs and put them into a ConcreteGarage, as long as it's simple: val newFerrari = new Ferrari(Benzin()) val newMustang = new Mustang(Benzin()) val ferrariGarage = new ConcreteGarage(Seq(newFerrari)) val mustangGarage = new ConcreteGarage(Seq(newMustang)) However, if I merely return one or the other, based on a flag, and try to put the result into a garage, it fails: val likesFord = true val new_car = if (likesFord) newFerrari else newMustang val switchedGarage = new ConcreteGarage(Seq(new_car)) // Fails here The switch alone works fine, it is the call to ConcreteGarage constructor that fails with the rather mystical error: error: inferred type arguments [this.Car[_ >: this.Ferrari with this.Mustang <: this.Car[_ >: this.Ferrari with this.Mustang <: ScalaObject]{def fuel: this.Benzin; type FuelType<: this.Benzin}]{def fuel: this.Benzin; type FuelType<: this.Benzin}] do not conform to class ConcreteGarage's type parameter bounds [C <: this.Car[C]] val switchedGarage = new ConcreteGarage(Seq(new_car)) // Fails here ^ I have tried putting those magic [C <: Car[C]] representation type parameters everywhere, but without success in finding the magic spot.

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  • genStrAsCharArray optimisation benefits

    - by Rich
    Hi I am looking into the options available to me for optimising the performance of JBoss 5.1.0. One of the options I am looking at is setting genStrAsCharArray to true in <JBOSS_HOME>/server/<PROFILE>/deployers/jbossweb.deployer/web.xml. This affects the generation of .java code from .JSPs. The comment describes this flag as: Should text strings be generated as char arrays, to improve performance in some cases? I have a few questions about this. Is this the generation of Strings in the dynamic parts of the JSP page (ie each time the page is called) or is it the generation of Strings in the static parts (ie when the .java is built from the JSP)? "in some cases" - which cases are these? What are the situations where the performance is worse? Does this speed up the generation of the .java, the compilation of the .class or the execution of the .class? At a more technical level (and the answer to this will probably depend on the answer to part 1), why can the use of char arrays improve performance? Thanks in advance Rich

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  • Strategies for dealing with Circular references caused by JPA relationships?

    - by ams
    I am trying to partition my application into modules by features packaged into separate jars such as feature-a.jar, feature-b.jar, ... etc. Individual feature jars such as feature-a.jar should contain all the code for a feature a including jpa entities, business logic, rest apis, unit tests, integration test ... etc. The problem I am running into is that bi-directional relationships between JPA entities cause circular references between the jar files. For example Customer entity should be in customer.jar and the Order should be in order.jar but Customer references order and order references customer making it hard to split them into separate jars / eclipse projects. Options I see for dealing with the circular dependencies in JPA entities: Option 1: Put all the entities into one jar / one project Option 2: Don't map certain bi-directianl relationships to avoid circular dependencies across projects. Questions: What rules / principles have you used to decide when to do bi-directional mapping vs. not? Have you been able to break jpa entities into their own projects / jar by features if so how did you avoid the circular dependencies issues?

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  • ActiveRecord Validations for Models with has_many, belongs_to associations and STI

    - by keruilin
    I have four models: User Award Badge GameWeek The associations are as follows: User has many awards. Award belongs to user. Badge has many awards. Award belongs to badge. User has many game_weeks. GameWeek belongs to user. GameWeek has many awards. Award belongs to game_week. Thus, user_id, badge_id and game_week_id are foreign keys in awards table. Badge implements an STI model. Let's just say it has the following subclasses: BadgeA and BadgeB. Some rules to note: The game_week_id fk can be nil for BadgeA, but can't be nil for BadgeB. Here are my questions: For BadgeA, how do I write a validation that it can only be awarded one time? That is, the user can't have more than one -- ever. For BadgeB, how do I write a validation that it can only be awarded one time per game week?

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  • Large ListView containing images in Android

    - by Marco W.
    For various Android applications, I need large ListViews, i.e. such views with 100-300 entries. All entries must be loaded in bulk when the application is started, as some sorting and processing is necessary and the application cannot know which items to display first, otherwise. So far, I've been loading the images for all items in bulk as well, which are then saved in an ArrayList<CustomType> together with the rest of the data for each entry. But of course, this is not a good practice, as you're very likely to have an OutOfMemoryException then: The references to all images in the ArrayList prevent the garbage collector from working. So the best solution is, obviously, to load only the text data in bulk whereas the images are then loaded as needed, right? The Google Play application does this, for example: You can see that images are loaded as you scroll to them, i.e. they are probably loaded in the adapter's getView() method. But with Google Play, this is a different problem, anyway, as the images must be loaded from the Internet, which is not the case for me. My problem is not that loading the images takes too long, but storing them requires too much memory. So what should I do with the images? Load in getView(), when they are really needed? Would make scrolling sluggish. So calling an AsyncTask then? Or just a normal Thread? Parametrize it? I could save the images that are already loaded into a HashMap<String,Bitmap>, so that they don't need to be loaded again in getView(). But if this is done, you have the memory problem again: The HashMap stores references to all images, so in the end, you could have the OutOfMemoryException again. I know that there are already lots of questions here that discuss "Lazy loading" of images. But they mainly cover the problem of slow loading, not too much memory consumption.

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  • Nested Data XML design

    - by esryl
    Looking to nest (to unlimited levels) elements in XML. Like so: <items> <item> <name>Item One</name> <item> <name>Item Two</name> </item> <item> <name>Item Three</name> <item> <name>Item Four</name> </item> <!-- etc... --> </item> </item> </items> However. While browsing for a solution I noticed in the comments of: http://stackoverflow.com/questions/988139/weird-nesting-in-xml while the above is well formed it would not validate against any sinsible DTD. Two things, what is a better way of nesting similar elements, and secondly what would be the design of the DTD. UPDATE: Would prefer to validate against an XML Schema rather than DTD.

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  • How to select LI except first and second ?

    - by Wazdesign
    Here is the structure of the content, I want to select all LI except the first two (ie no-link) jQuery(document).ready(function(){ var nosubnav = jQuery('.first-level li:not(:has(ul))'); var nosubnavsize = jQuery('.first-level li:not(:has(ul))').size(); jQuery(nosubnav).css('border' , '1px solid red'); alert('List item which does not have submenu '+nosubnavsize); }); div class="navigation-container"> <ul class="first-level"> <li><a href="#">No Link</a></li> <li><a href="#">No Link</a></li> <li><a href="#">Link 1</a></li> <li><a href="#">Link 2</a> <ul> <li><a href="#">Link2.1</a></li> <li><a href="#">Link2.2</a> <ul> <li><a href="#">Link 2.2.1</a></li> </ul> </li> </ul> </li> <li><a href="#">Link </a></li> </ul> </div> related Question : http://stackoverflow.com/questions/2771801/how-to-count-li-which-does-not-have-ul

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  • Does the pointer to free() have to point to beginning of the memory block, or can it point to the interior?

    - by Lambert
    The question is in the title... I searched but couldn't find anything. Edit: I don't really see any need to explain this, but because people think that what I'm saying makes no sense (and that I'm asking the wrong questions), here's the problem: Since people seem to be very interested in the "root" cause of all the problem rather than the actual question asked (since that apparently helps things get solved better, let's see if it does), here's the problem: I'm trying to make a D runtime library based on NTDLL.dll, so that I can use that library for subsystems other than the Win32 subsystem. So that forces me to only link with NTDLL.dll. Yes, I'm aware that the functions are "undocumented" and could change at any time (even though I'd bet a hundred dollars that wcstombs will still do the same exact thing 20 years from now, if it still exists). Yes, I know people (especially Microsoft) don't like developers linking to that library, and that I'll probably get criticized for the right here. And yes, those two points above mean that programs like chkdsk and defragmenters that run before the Win32 subsystem aren't even supposed to be created in the first place, because it's literally impossible to link with anything like kernel32.dll or msvcrt.dll and still have NT-native executables, so we developers should just pretend that those stages are meant to be forever out of our reaches. But no, I doubt that anyone here would like me to paste a few thousand lines of code and help me look through them and try to figure out why memory allocations that aren't failing are being rejected by the source code I'm modifying. So that's why I asked about a different problem than the "root" cause, even though that's supposedly known to be the best practice by the community. If things still don't make sense, feel free to post comments below! :)

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