Search Results

Search found 9011 results on 361 pages for 'common'.

Page 280/361 | < Previous Page | 276 277 278 279 280 281 282 283 284 285 286 287  | Next Page >

• Single intent to let user take picture OR pick image from gallery in Android

  - by Damian

  I'm developing an app for Android 2.1 upwards. I want to enable my users to select a profile picture within my app (I'm not using the contacts framework). The ideal solution would be to fire an intent that enables the user to select an image from the gallery, but if an appropriate image is not available then use the camera to take a picture (or vice-versa i.e. allow user to take picture but if they know they already have a suitable image already, let them drop into the gallery and pick said image). Currently I can do one or the other but not both. If I go directly into camera mode using MediaStore.ACTION_IMAGE_CAPTURE then there is no option to drop into the gallery. If I go directly to the gallery using Intent.ACTION_PICK then I can pick an image but if I click the camera button (in top right hand corner of gallery) then a new camera intent is fired. So, any picture that is taken is not returned directly to my application. (Sure you can press the back button to drop back into the gallery and select image from there but this is an extra unnecessary step and is not at all intuitive). So is there a way to combine both or am I going to have to offer a menu to do one or the other from within my application? Seems like it would be a common use case...surely I'm missing something?

  Read the article

• How to rdc to a particular machine that is member of a TS Farm?

  - by Amit Arora

  I created a Terminal Services farm comprising of 3 TS hosts (say, TS1, TS2 and TS3) running Windows 2008 R2 Enterprise, a TS Connection broker and a TS Gateway for the purpose of hosting a windows application as a TS RemoteApp. The setup works just fine. Now, I want to do some further configuration changes on a particular TS host, say TS2 and not on any other TS host. I try to rdc to TS2 but I find myself getting connected to a randomly chosen TS host (sometimes TS1, sometimes TS2, and at other times, TS3). I think rdc connection is also going via the Connection Broker that is forwarding me to a TS host it decides is best. Is there a way I can deterministically connect to a particular TS host using rdc? I don't have option to login locally on a TS host as the entire setup is hosted in a remote data center. I think this is a very common scenario and must have a straight forward solution. It could be as easy as doing rdc to Connection Broker server and disabling it for a while, but I don't know how to do that too. Any help will be highly appreciated.

  Read the article

• what are all the Optimize tricks that you know for asp.net code ?

  - by Aristos

  After some time of many code programming on asp.net, I discover the very big speed different between string and StringBuilder. I know that is very common and known but I just mention it for start. The second think that I have found to speed up the code, is to use the const, and not the static, for declare my configuration constants value (especial the strings). With the const, the compiler not create new object, but just place the value, on the point that you have ask it, but with the static declaration, is create a new memory object and keep its on the memory. My third trick, is when I search for string, I use hash values, and not the string itself. For example, if I need a List<string SomeValues, and place inside strings that I need to search them, I prefer to use List<int SomeHashValue, and I use the hash value to locate the strings. My forth thought that I was wandering, is if is better to place big strings in one line, or separate them in different lines with the + symbol to be more easy to read out. I make some tests and see that the compiler make a good job is some split the string, in many lines, using the + symbol. What other tricks/tips do you know and use on your programming to make it run faster, and maybe use less memory. Well I know, that some times, to make something run faster, you need more memory, more cache. My priority is on speed. Because Speed Counts.

  Read the article

• magento payment process.. how it works in general

  - by spirytus

  hi everyone, got a question and I hope this is right place to ask :).. don’t quite understand how payment works in magento. client goes to checkout and lets say wants to pay as a guest, so provides address etc. and finally gets to payment methods. Then I want clients to pay thru credit card. Already have module installed for gateway (bank?) of my choice. At that point I would expect users to be redirected to 3rd party page (bank hosted) where they giving all the details, only after being returned to my magento site with appropriate message. In magento however it seems like they need to provide cc numbers and details on magento checkout page. I don’t understand if I (or the payment module I installed) need to transfer then all the credit card details to bank? I would have to have checkout page on ssl connection and static ip right? The thing is I want to avoid touching CC numbers at any point and would love to have it done by a bank page. I like the idea of magento interface all the way without redirecting to another page though, the only problem is not sure if would be able to set it all up properly. If anyone could explain to me possible options, what is the common way to do it and how the whole process works that would be very much appreciated. I did my research and looked all over google and various forums still need someones help though. Please let me know if some parts of my question are not quite clear, will try to better explain if necessary.

  Read the article

• Partially constructed object / Multi threading

  - by reto

  Heya! I'm using joda due to it's good reputation regarding multi threading. It goes great distances to make multi threaded date handling efficient, for example by making all Date/Time/DateTime objects immutable. But here's a situation where I'm not sure if Joda is really doing the right thing. It probably is correct, but I'd be very interested to see the explanation for it. When a toString() of a DateTime is being called Joda does the following: /* org.joda.time.base.AbstractInstant */ public String toString() { return ISODateTimeFormat.dateTime().print(this); } All formatters are thread safe, as they are as well ready-only. But what's about the formatter-factory: private static DateTimeFormatter dt; /* org.joda.time.format.ISODateTimeFormat */ public static DateTimeFormatter dateTime() { if (dt == null) { dt = new DateTimeFormatterBuilder() .append(date()) .append(tTime()) .toFormatter(); } return dt; } This is a common pattern in single threaded applications. I see the following dangers: Race condition during null check -- worst case: two objects get created. No Problem, as this is solely a helper object (unlike a normal singleton pattern situation), one gets saved in dt, the other is lost and will be garbage collected sooner or later. the static variable might point to a partially constructed object before the objec has been finished initialization (before calling me crazy, read about a similar situation in this Wikipedia article. So how does Joda ensure that not partially created formatter gets published in this static variable? Thanks for your explanations! Reto

  Read the article

• Cannot launch 16-bit application anymore

  - by Nick Bedford

  I'm trying to debug and resolve some issues with a Win32 macro application written C++ however I'm having the strangest issue. I have to launch a 16-bit program and then simulate entering data into and have been using ShellExecute for over two years now. I haven't touched this actual code at all, but now it doesn't work. I'm doing ShellExecute(NULL, "open", exe_path.c_str(), NULL, "", SW_SHOWDEFAULT);. This has worked flawlessly for years but all of sudden, it stopped working. It gives me an ACCESS_DENIED error code. I've Googled and apparently this is a pretty common issue with launching 16-bit apps. The workstation XP SP2 environment hasn't changed at all, and it was actually working until I rebuilt a little while ago (I've rebuilt it before many times). The code is inside a window procedure function and when I take it out and launch the program in the WinMain function it works, but the code has to be in the window procedure... I've tried numerous alternatives but they all give the same issue. The biggest issue with this is it was working then all of a sudden decided it wasn't going to with no change to both code and environment! In fact, it was about half way through testing changes that it thought it'd stop working. Please help as I cannot do anything without the program launching. It's the first step in the code that I'm debugging!

  Read the article

• When I include only the jQuery 1.4 Library, I get an exception, why?

  - by codeninja

  I keep getting this error all over the place where I only have jquery 1.3 or 1.4 included. "setting a property that has only a getter" and a long list of warnings in the Firefox Error Console. What's going on? I can't find any information on this issue =/ <!DOCTYPE HTML PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd"> <html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en-US"> <head> <title>Demo</title> <meta http-equiv="Content-Type" content="text/html; charset=UTF-8"> <link rel="shortcut icon" href="images/favicon.ico"> <link rel="stylesheet" href="css/common.css" type="text/css" /> <link rel="stylesheet" href="css/modules.css" type="text/css" /> <script type="text/javascript" src="js/jquery-1.4.2.min.js"></script> </head> Just some Warning snippets: Warning: reference to undefined property a[++e] Source File: /js/jquery-1.4.2.min.js Line: 30 Warning: reference to undefined property a[0] Source File: /js/jquery-1.4.2.min.js Line: 30 Warning: function oa does not always return a value Source File: /js/jquery-1.4.2.min.js Line: 18, Column: 165 Source Code: th;n<r;n++){j=d[n];a.currentTarget=j.elem;a.data=j.handleObj.data;a.handleObj=j.handleObj;if(j.handleObj.origHandler.apply(j.elem,e)===false){b=false;break}}return b}}function pa(a,b){return"live."+(a&&a!=="*"?a+".":"")+b.replace(/\./g,"`").replace(/ /g,

  Read the article

• Discussion on SEO best-practices for site development involving php...

  - by Bradley Herman

  Recently in our work, I've started getting some experience with SEO (finally). It's something I've put off for a long time because I've always maintained that SEO is a buzz-word b.s. pseudo-science and more about providing quality, relevant content (assuming proper header tags and the basics are covered). However, sometimes a client doesn't have stellar content yet still demands SEO and high rankings. While it's not how I design sites 100% of the time (as design dictates structure), I typically create a basic template from the design my boss gives me, then I optimize it, and then strip the top and bottom and move those to header.php and footer.php, using the following to bring in the header and footer based on AJAX versus HTML requests: <?php if($_SERVER['HTTP_X_REQUESTED_WITH']==''){ include('includes/header.php'); }?> #content here <?php if($_SERVER['HTTP_X_REQUESTED_WITH']==''){ include('includes/footer.php'); }?> Then, I use jQuery to intercept page requests and I use AJAX to fill in, for example, a #copy div with the new content. This avoids unnecessarily loading all the header and footer info everytime, but still allows users without Java to access pages without any problems. (also to think about, depending on size of content, do the extra http requests added using this method render it more of a server strain versus a single, larger file?) I don't have a really solid understanding of the meta keywords and their SEO significance, but as I recall reading, the keywords, title, and description on a page should match up to the pages content--ie. each page should have slightly different keywords/description while retaining some common ground. What I'm getting at here is trying to foster a discussion on whether my approach is flawed to begin with, if there are things I can do (within reason) that keep the site structure simple but allow for better SEO practices, or if my SEO understandings are wrong. This isn't a question, per say, but hopefully a constructive discussion here that more than just I can learn from. I appreciate any responses and hope to hear from you. Thanks!

  Read the article

• sql-server performance optimization by removing print statements

  - by AG

  We're going through a round of sql-server stored procedure optimizations. The one recommendation we've found that clearly applies for us is 'SET NOCOUNT ON' at the top of each procedure. (Yes, I've seen the posts that point out issues with this depending on what client objects you run the stored procedures from but these are not issues for us.) So now I'm just trying to add in a bit of common sense. If the benefit of SET NOCOUNT ON is simply to reduce network traffic by some small amount every time, wouldn't it also make sense to turn off all the PRINT statements we have in the stored procedures that we only use for debugging? I can't see how it can hurt performance. OTOH, it's a bit of a hassle to implement due to the fact that some of the print statements are the only thing within else clauses, so you can't just always comment out the one line and be done. The change carries some amount of risk so I don't want to do it if it isn't going to actually help. But I don't see eliminating print statements mentioned anywhere in articles on optimization. Is that because it is so obvious no one bothers to mention it?

  Read the article

• is there a Universal Model for languages?

  - by Smandoli

  Many programming languages share generic and even fairly universal features. For example, if you compared Java, VB6, .NET, PHP, Python, then you would find common functions such as control structures, numeric and string manipulation, etc. What has been done to define these features at a meta-language (or language-agnostic) level? UML offers a descriptive reference of software in every aspect, but the real-world focus seems to be data processes. Is UML relevant? I'm not asking "Why we don't have a single language that replaces the current plethora." We need many different tools (at least in this eon). I'm not asking that all languages fit a template -- assembly vs. compiled languages are different enough to make that unfeasible (and some folks call HTML a language, though I wouldn't). Any attempt would start with a properly narrow scope. In line with this, I wouldn't expect the model to cover even a small selection with full validity. I would expect however that such a model could be used to transpose from one language to another (with limited goals -- think jist translation).

  Read the article

• Looking for pros/cons of using GWT or JSF

  - by cliff.meyers

  I'm a long time Java developer who has been building UI with Adobe Flex for the past few years. I'm looking to broaden my repertoire with a RIA technology that runs in a plain-old browser, no plug-ins required. I've read a lot about GWT but don't know much about JSF, especially given the varying implementations. Below are some criteria that are important to me as a developer. I'm hoping that the community might be able to tell me about the strengths and weaknesses of GWT and JSF in each: Layout: is it declarative, programmatic or a mix of both? Control library: how rich is the available control library? How easy is it to extend or write custom controls that "play nice" with the built-ins? Javascript: how much of it do I need to write in order to be successful with the framework? Cross-browser: assuming I'm not writing a lot of my own HTML and JS, do the frameworks function equally well in all modern browsers? Tooling: is a rapid edit/refresh cycle available? How easy is it to debug the client and server code? Bookmarking / Browser Navigation: this is a common problem in Flex; does the framework play nicely with these? I would love to hear any other important pros / cons I might not have covered. Thanks!

  Read the article

• CALayer and Off-Screen Rendering

  - by Luke Mcneice

  I have a Paging UIScrollView with a contentSize large enough to hold a number of small UIScrollViews for zooming, The viewForZoomingInScrollView is a viewController that holds a CALayer for drawing a PDF page onto. This allows me to navigate through a PDF much like the ibooks PDF reader. The code that draws the PDF (Tiled Layers) is located in: - (void)drawLayer:(CALayer *)layer inContext:(CGContextRef)ctx; And simply adding a 'page' to the visible screen calls this method automatically. When I change page there is some delay before all the tiles are drawn, even though the object (page) has already been created. What i want to be able to do is render the next page before the user scrolls to it, thus preventing the visible tiling effect. However, i have found that if the layer is located offscreen adding it to the scrollview doesn't call the drawLayer. Any Ideas/common gotchas here? I have tried: [viewController.view.layer setNeedsLayout]; [viewController.view.layer setNeedsDisplay]; NB: The fact that this is replicating the ibooks functionally is irrelevant within the context of the full app.

  Read the article

• ASP.Net MVC: Showing the same data using different layouts...

  - by vdh_ant

  Hi guys I'm wanting to create a page that allows the users to select how they would like to view their data - i.e. summary (which supports grouping), grid (which supports grouping), table (which supports grouping), map, time line, xml, json etc. Now each layout would probably have different use a different view model, which inherit from a common base class/view model. The reason being that each layout needs the object structure that it deals with to be different (some need hierarchical others a flatter structure). Each layout would call the same repository method and each layout would support the same functionality, i.e. searching and filtering (hence these controls would be shared between layouts). The main exception to this would be sorting which only grid and table views would need to support. Now my question is given this what do people think is the best approach. Using DisplayFor to handle the rendering of the different types? Also how do I work this with the actions... I would imagine that I would use the one action, and pass in the layout types, but then how does this support the grouping required for the summary, grid and table views. Do i treat each grouping as just a layout type Also how would this work from a URL point of view - what do people think is the template to support this layout functionality Cheers Anthony

  Read the article

• Returning the same type the function was passed

  - by Ken Bloom

  I have the following code implementation of Breadth-First search. trait State{ def successors:Seq[State] def isSuccess:Boolean = false def admissableHeuristic:Double } def breadthFirstSearch(initial:State):Option[List[State]] = { val open= new scala.collection.mutable.Queue[List[State]] val closed = new scala.collection.mutable.HashSet[State] open.enqueue(initial::Nil) while (!open.isEmpty){ val path:List[State]=open.dequeue() if(path.head.isSuccess) return Some(path.reverse) closed += path.head for (x <- path.head.successors) if (!closed.contains(x)) open.enqueue(x::path) } return None } If I define a subtype of State for my particular problem class CannibalsState extends State { //... } What's the best way to make breadthFirstSearch return the same subtype as it was passed? Supposing I change this so that there are 3 different state classes for my particular problem and they share a common supertype: abstract class CannibalsState extends State { //... } class LeftSideOfRiver extends CannibalsState { //... } class InTransit extends CannibalsState { //... } class RightSideOfRiver extends CannibalsState { //... } How can I make the types work out so that breadthFirstSearch infers that the correct return type is CannibalsState when it's passed an instance of LeftSideOfRiver? Can this be done with an abstract type member, or must it be done with generics?

  Read the article

• Web Shop Schema - Document Db

  - by Maxem

  I'd like to evaluate a document db, probably mongo db in an ASP.Net MVC web shop. A little reasoning at the beginning: There are about 2 million products. The product model would be pretty bad for rdbms as there'd be many different kinds of products with unique attributes. For example, there'd be books which have isbn, authors, title, pages etc as well as dvds with play time, directors, artists etc and quite a few more types. In the end, I'd have about 9 different products with a combined column count (counting common columns like title only once) of about 70 to 100 whereas each individual product has 15 columns at most. The three commonly used ways in RDBMS would be: EAV model which would have pretty bad performance characteristics and would make it either impractical or perform even worse if I'd like to display the author of a book in a list of different products (think start page, recommended products etc.). Ignore the column count and put it all in the product table: Although I deal with somewhat bigger databases (row wise), I don't have any experience with tables with more than 20 columns as far as performance is concered but I guess 100 columns would have some implications. Create a table for each product type: I personally don't like this approach as it complicates everything else. C# Driver / Classes: I'd like to use the NoRM driver and so far I think i'll try to create a product dto that contains all properties (grouped within detail classes like book details, except for those properties that should be displayed on list views etc.). In the app I'll use BookBehavior / DvdBehaviour which are wrappers around a product dto but only expose the revelent Properties. My questions now: Are my performance concerns with the many columns approach valid? Did I overlook something and there is a much better way to do it in an RDBMS? Is MongoDb on Windows stable enough? Does my approach with different behaviour wrappers make sense?

  Read the article

• How to write custom (odd) authentication plugins for Wordpress, Joomla and MediaWiki?

  - by Bart van Heukelom

  On our network (a group of related websites - not a LAN) we have a common authentication system which works like this: On a network site ("consumer") the user clicks on a login link This redirects the user to a login page on our auth system ("RAS"). Upon successful login the user is directed back to the consumer site. Extra data is passed in the query string. This extra data does not include any information about the user yet. The consumer site's backend contacts RAS, with this extra data, to get the information about the logged in user (id, name, email, preferences, etc.). So as you can see, the consumer site knows nothing about the authentication method. It doesn't know if it's by username/password, fingerprint, smartcard, or winning a game of poker. This is the main problem I'm encountering when trying to find out how I could write custom authentication plugins for these packages, acting as consumer sites: Wordpress Joomla MediaWiki For example Joomla offers a pretty simple auth plugin system, but it depends on a username/password entered on the Joomla site. Any hints on where to start?

  Read the article

• Compiling Objective-C project on Linux (Ubuntu)

  - by Alex

  How to make an Objective-C project work on Ubuntu? My files are: Fraction.h #import <Foundation/NSObject.h> @interface Fraction: NSObject { int numerator; int denominator; } -(void) print; -(void) setNumerator: (int) n; -(void) setDenominator: (int) d; -(int) numerator; -(int) denominator; @end Fraction.m #import "Fraction.h" #import <stdio.h> @implementation Fraction -(void) print { printf( "%i/%i", numerator, denominator ); } -(void) setNumerator: (int) n { numerator = n; } -(void) setDenominator: (int) d { denominator = d; } -(int) denominator { return denominator; } -(int) numerator { return numerator; } @end main.m #import <stdio.h> #import "Fraction.h" int main( int argc, const char *argv[] ) { // create a new instance Fraction *frac = [[Fraction alloc] init]; // set the values [frac setNumerator: 1]; [frac setDenominator: 3]; // print it printf( "The fraction is: " ); [frac print]; printf( "\n" ); // free memory [frac release]; return 0; } I've tried two approaches to compile it: Pure gcc: $ sudo apt-get install gobjc gnustep gnustep-devel $ gcc `gnustep-config --objc-flags` -o main main.m -lobjc -lgnustep-base /tmp/ccIQKhfH.o:(.data.rel+0x0): undefined reference to `__objc_class_name_Fraction' I created a GNUmakefile Makefile: include ${GNUSTEP_MAKEFILES}/common.make TOOL_NAME = main main_OBJC_FILES = main.m include ${GNUSTEP_MAKEFILES}/tool.make ... and ran: $ source /usr/share/GNUstep/Makefiles/GNUstep.sh $ make Making all for tool main... Linking tool main ... ./obj/main.o:(.data.rel+0x0): undefined reference to `__objc_class_name_Fraction' So in both cases compiler gets stuck at undefined reference to `__objc_class_name_Fraction' Do you have and idea how to resolve this issue?

  Read the article

• How would you mask data returned in a Dynamic Data for Entities website?

  - by David Stratton

  I'm doing this in Visual Studio 2008, not 2010, in case there is a relevant difference between the two versions of the Dynamic Data websites. How would I mask data in the automatically generated tables in a Dynamic Data for Entities website? The scenario is we have one table where we want to allow users to ENTER sensitive data, but not VIEW sensitive data, so... (In the list below, I'm using "template" to mean "The web page generated automatically based on the schema and action. I'm sure that's the wrong terminology, but the meaning should be clear.) The "Insert" template should have the field's textbox available for the user to type a value in. The "Edit" template should have the field's textbox blanked out (empty string) regardless of what was in the field in the database in the first place, but the user should be able to type in new data and have it save The "View" template should either have the data for this field masked, or non-visible. The auto-generated table showing the list of records should also have this field masked or non-visible. I can do this easily with standard Web Forms, but I'm having a hard time figuring this out in the Dynamic Data site I'm working on. Masking data is such a common task, I have to believe Microsoft thought of this and provided a way to do it...

  Read the article

• Left/Right/Inner joins using C# and LINQ

  - by Keith Barrows

  I am trying to figure out how to do a series of queries to get the updates, deletes and inserts segregated into their own calls. I have 2 tables, one in each of 2 databases. One is a Read Only feeds database and the other is the T-SQL R/W Production source. There are a few key columns in common between the two. What I am doing to setup is this: List<model.AutoWithImage> feedProductList = _dbFeed.AutoWithImage.Where(a => a.ClientID == ClientID).ToList(); List<model.vwCompanyDetails> companyDetailList = _dbRiv.vwCompanyDetails.Where(a => a.ClientID == ClientID).ToList(); foreach (model.vwCompanyDetails companyDetail in companyDetailList) { List<model.Product> productList = _dbRiv.Product.Include("Company").Where(a => a.Company.CompanyId == companyDetail.CompanyId).ToList(); } Now that I have a (source) list of products from the feed, and an existing (target) list of products from my prod DB I'd like to do 3 things: Find all SKUs in the feed that are not in the target Find all SKUs that are in both, that are active feed products and update the target Find all SKUs that are in both, that are inactive and soft delete from the target What are the best practices for doing this without running a double loop? Would prefer a LINQ 4 Objects solution as I already have my objects. EDIT: BTW, I will need to transfer info from feed rows to target rows in the first 2 instances, just set a flag in the last instance. TIA

  Read the article

• HTML file: add annotations through IHTMLDocument

  - by peterchen

  I need to add "annotations" to existing HTML documents - best in the form of string property values I can read & write by name. Apparently (to me), meta elements in the header seem to be the common way - i.e. adding/modifying elements like <head> <meta name="unique-id_property-name" content="property-value"/> ... </head> Question 1: Ist that "acceptable" / ok, or is there a better way to add meta data? I have a little previous experience with getting/mut(il)ating HTML contents through the document in an web browser control. For this task, I've already loaded the HTML document into a HTMLDocument object, but I'm not sure how to go on: // what I have IHTMLDocument2Ptr doc; doc.CreateInstance(__uuidof(HTMLDocument)); IPersistFile pf = doc; pf->Load(fileName, STGM_READ); // everything ok until here Questions 2: Should I be using anything else than HTMLDocument? Questions 3..N: How do I get the head element? How do I get the value of a meta element with a given name? How do I set the value of a meta element (adding the item if and only if it doesn't exist yet)? doc->all returns a collection of all tags, which I can enumerate even though count returns 0. I could scan that for head, then scan that for all meta where the name starts with a certain string, etc. - but this feels very clumsy.

  Read the article

• C++0x rvalue references and temporaries

  - by Doug

  (I asked a variation of this question on comp.std.c++ but didn't get an answer.) Why does the call to f(arg) in this code call the const ref overload of f? void f(const std::string &); //less efficient void f(std::string &&); //more efficient void g(const char * arg) { f(arg); } My intuition says that the f(string &&) overload should be chosen, because arg needs to be converted to a temporary no matter what, and the temporary matches the rvalue reference better than the lvalue reference. This is not what happens in GCC and MSVC. In at least G++ and MSVC, any lvalue does not bind to an rvalue reference argument, even if there is an intermediate temporary created. Indeed, if the const ref overload isn't present, the compilers diagnose an error. However, writing f(arg + 0) or f(std::string(arg)) does choose the rvalue reference overload as you would expect. From my reading of the C++0x standard, it seems like the implicit conversion of a const char * to a string should be considered when considering if f(string &&) is viable, just as when passing a const lvalue ref arguments. Section 13.3 (overload resolution) doesn't differentiate between rvalue refs and const references in too many places. Also, it seems that the rule that prevents lvalues from binding to rvalue references (13.3.3.1.4/3) shouldn't apply if there's an intermediate temporary - after all, it's perfectly safe to move from the temporary. Is this: Me misreading/misunderstand the standard, where the implemented behavior is the intended behavior, and there's some good reason why my example should behave the way it does? A mistake that the compiler vendors have somehow all made? Or a mistake based on common implementation strategies? Or a mistake in e.g. GCC (where this lvalue/rvalue reference binding rule was first implemented), that was copied by other vendors? A defect in the standard, or an unintended consequence, or something that should be clarified?

  Read the article

• How can I make a family of singletons?

  - by Jay

  I want to create a set of classes that share a lot of common behavior. Of course in OOP when you think that you automatically think "abstract class with subclasses". But among the things I want these classes to do is to each have a static list of instances of the class. The list should function as sort of a singleton within the class. I mean each of the sub-classes has a singleton, not that they share one. "Singleton" to that subclass, not a true singleton. But if it's a static, how can I inherit it? Of course code like this won't work: public abstract A { static List<A> myList; public static List getList() { if (myList==null) myList=new ArrayList<A>(10); return myList; } public static A getSomethingFromList() { List listInstance=getList(); ... do stuff with list ... } public int getSomethingFromA() { ... regular code acting against current instance ... } } public class A1 extends A { ... } public class A2 extends A { ... } A1 somethingfromA1List=(A1) A1.getSomethingFromList(); A2 somethingfromA2List=(A2) A2.getSomethingFromList(); The contents of the list for each subclass would be different, but all the code to work on the lists would be the same. The problem with the above code is that I'd only have one list for all the subclasses, and I want one for each. Yes, I could replicate the code to declare the static list in each of the subclasses, but then I'd also have to replicate all the code that adds to the lists and searches the list, etc, which rather defeats the purpose of subclassing. Any ideas on how to do this without replicating code?

  Read the article

• Binary Search Tree for specific intent

  - by Luís Guilherme

  We all know there are plenty of self-balancing binary search trees (BST), being the most famous the Red-Black and the AVL. It might be useful to take a look at AA-trees and scapegoat trees too. I want to do deletions insertions and searches, like any other BST. However, it will be common to delete all values in a given range, or deleting whole subtrees. So: I want to insert, search, remove values in O(log n) (balanced tree). I would like to delete a subtree, keeping the whole tree balanced, in O(log n) (worst-case or amortized) It might be useful to delete several values in a row, before balancing the tree I will most often insert 2 values at once, however this is not a rule (just a tip in case there is a tree data structure that takes this into account) Is there a variant of AVL or RB that helps me on this? Scapegoat-trees look more like this, but would also need some changes, anyone who has got experience on them can share some thougts? More precisely, which balancing procedure and/or removal procedure would help me keep this actions time-efficient?

  Read the article

• Populating a foreign key table with variable user input

  - by Vincent

  I'm working on a website that will be based on user contributed data, submitted using a regular HTML form. To simplify my question, let's say that there will be two fields in the form: "User Name" and "Country" (this is just an example, not the actual site). There will be two tables in the database : "countries" and "users," with "users.country_id" being a foreign key to the "countries" table (one-to-many). The initial database will be empty. Users from all over the world will submit their names and the countries they live in and eventually the "countries" table will get filled out with all of the country names in the world. Since one country can have several alternative names, input like Chile, Chili, Chilli will generate 3 different records in the countries table, but in fact there is only one country. When I search for records from Chile, Chili and Chilli will not be included. So my question is - what would be the best way to deal with a situation like this, with conditions such that the initial database is empty, no other resources are available and everything is based on user input? How can I organize it in such way that Chile, Chili and Chilli would be treated as one country, with minimum manual interference. What are the best practices when it comes to normalizing user submitted data and is there a scientific term for this? I'm sure this is a common problem. Again, I used country names just to simplify my question, it can be anything that has possible different spellings.

  Read the article

• Getting rid of nested using(...) statements

  - by Ghostrider

  Sometimes I need to use several disposable objects within a function. Most common case is having StreamReader and StreamWriter but sometimes it's even more than this. Nested using statements quickly add up and look ugly. To remedy this I've created a small class that collects IDisposable objects and disposes of them when it itself is disposed. public class MultiDispose : HashSet<IDisposable>, IDisposable { public MultiDispose(params IDisposable[] objectsToDispose) { foreach (IDisposable d in objectsToDispose) { this.Add(d); } } public T Add<T>(T obj) where T : IDisposable { base.Add(obj); return obj; } public void DisposeObject(IDisposable obj) { obj.Dispose(); base.Remove(obj); } #region IDisposable Members public void Dispose() { foreach (IDisposable d in this) { d.Dispose(); } } #endregion } So my code now looks like this: using (MultiDispose md = new MultiDispose()) { StreamReader rdr = md.Add(new StreamReader(args[0])); StreamWriter wrt = md.Add(new StreamWriter(args[1])); WhateverElseNeedsDisposing w = md.Add(new WhateverElseNeedsDisposing()); // code } Is there anything wrong with this approach that can cause problems down the road? I left the Remove function inherited from the HashSet on purpose so that the class would be more flexible. Surely misusing this function can lead to objects not being disposed of properly, but then there many other ways to shoot yourself in the foot without this class.

  Read the article

< Previous Page | 276 277 278 279 280 281 282 283 284 285 286 287  | Next Page >