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  • How to optimize paging for large in memory database

    - by snakefoot
    I have an application where the entire database is implemented in memory using a stl-map for each table in the database. Each item in the stl-map is a complex object with references to other items in the other stl-maps. The application works with a large amount of data, so it uses more than 500 MByte RAM. Clients are able to contact the application and get a filtered version of the entire database. This is done by running through the entire database, and finding items relevant for the client. When the application have been running for an hour or so, then Windows 2003 SP2 starts to page out parts of the RAM for the application (Eventhough there is 16 GByte RAM on the machine). After the application have been partly paged out then a client logon takes a long time (10 mins) because it now generates a page fault for each pointer lookup in the stl-map. I can see it is possible to tell Windows to lock memory in RAM, but this is generally only recommended for device drivers, and only for "small" amounts of memory. I guess a poor mans solution could be to loop through the entire memory database, and thus tell Windows we are still interested in keeping the datamodel in RAM. I guess another poor mans solution could be to disable the pagefile completely on Windows. I guess the expensive solution would be a SQL database, and then rewrite the entire application to use a database layer. Then hopefully the database system will have implemented means to for fast access. Are there other more elegant solutions ?

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  • Develop multiple very similar projects at once

    - by Raveren
    I am developing a semi-complicated site that is available in several countries at once. Much effort has been put in to make the code bases as similar as possible to one another and ultimately only the config file and some representational data will differ between them. Each project has its own SVN repository which maps directly to a live test site. That part is handled by the IDE we use to work. Now I am in need to create a some sort of system to keep all these projects in sync. The best theoretical solution so far is to create a local hook script that would fire on committing and Merge the committed files from the project that is being committed to all other projects Optionally upload them to the live site, replacing previous files The first problem is that I don't know how I would do the merging - I guess it would be like applying a SVN patch or something. The second is if I do not want to upload the changes to the live server, how would I go about synching the live and local code bases (replace older files?). I am posting this question, not going through the potentially huge trouble of solving the aforementioned problems myself is that I believe this is a pretty common situation and someone would already have a solution and others may benefit from the answers in the future. Lastly, I'm on windows7, develop PHP and use tortoiseSVN.

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  • Does NSClassFromString affect performance?

    - by Tomen
    I want to create a controller that depends on the class of a given instance of a model -(BaseController *)getControllerForModel:(Model *)model { BaseController *controller = nil; Class controllerClass = [BaseController class]; //the default value //find the right controller if ([model isMemberOfClass:[ModelClass1 class]]) controllerClass = [ConcreteController1 class]; else if ([model isMemberOfClass:[ModelClass2 class]]) controllerClass = [ConcreteController2 class]; else if ([model isMemberOfClass:[ModelClass3 class]]) controllerClass = [ConcreteController3 class]; ... else if ([model isMemberOfClass:[ModelClassX class]]) controllerClass = [ConcreteControllerX class]; else Trace(TRACELEVEL_WARNING, @"Unrecognized model type: %@", NSStringFromClass([model class])); //Now instantiate it with the model controller = [[[controllerClass alloc] initWithModel:model] autorelease]; return slotController; } I want to find a more flexible solution to this and thought of having a dictionary, which maps Model-Classes to Controller-Classes and then NSClassFromString could give me the right instance. My question is this: Is NSClassFromString using much of my applications performance if i use it several times (say, 100 times at once)? Or would it be about as fast as the above approach?

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  • How to mix Grammer (Rules) & Dictation (Free speech) with SpeechRecognizer in C#

    - by Lee Englestone
    I really like Microsofts latest speech recognition (and SpeechSynthesis) offerings. http://msdn.microsoft.com/en-us/library/ms554855.aspx http://estellasays.blogspot.com/2009/04/speech-recognition-in-cnet.html However I feel like I'm somewhat limited when using grammers. Don't get me wrong grammers are great for telling the speech recognition exactly what words / phrases to look out for, however what if I want it to recognise something i've not given it a heads up about? Or I want to parse a phrase which is half pre-determined command name and half random words? For example.. Scenario A - I say "Google [Oil Spill]" and I want it to open Google with search results for the term in brackets which could be anything. Scenario B - I say "Locate [Manchester]" and I want it to search for Manchester in Google Maps or anything else non pre-determined I want it to know that 'Google' and 'Locate' are commands and what comes after it are parameters (and could be anything). Question : Does anyone know how to mix the use of pre-determined grammers (words the speech recognition should recognise) and words not in its pre-determined grammer? Code fragments.. using System.Speech.Recognition; ... ... SpeechRecognizer rec = new SpeechRecognizer(); rec.SpeechRecognized += rec_SpeechRecognized; var c = new Choices(); c.Add("search"); var gb = new GrammarBuilder(c); var g = new Grammar(gb); rec.LoadGrammar(g); rec.Enabled = true; ... ... void rec_SpeechRecognized(object sender, SpeechRecognizedEventArgs e) { if (e.Result.Text == "search") { string query = "How can I get a word not defined in Grammer recognised and passed into here!"; launchGoogle(query); } } ... ... private void launchGoogle(string term) { Process.Start("IEXPLORE", "google.com?q=" + term); }

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  • Does running IIS7 in classic mode affect MVC output caching?

    - by Bob
    I have a need to run an application in classic mode for backwards compatibility with a specific application, and am trying to understand what kind of impact that will have on the performance of an MVC application that is running on the site. If we put a few static file maps (for .js, .css, .png, etc) above the ASP.NET wildcard map to reduce the amount of processing by the ASP.NET handler, will we be approaching the integrated mode in terms of performance? The thing i'm primarily concerned with is any effect this might have on output caching. I understand that integrated mode might (?) allow for the output cache to handle non ASP.NET content, but that isn't really a concern. We're more interested in ensuring that the MVC application has full use of the output cache. Empirically i've found that the two configurations operate on par when things go well, but if the page references resources that are not available, the integrated mode tends to fail much more quickly than the classic mode (e.g. 500 ms vs 10 seconds), reducing 'hang time' on the page load. Thanks for any feedback.

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  • What is jQuery for Document.createElementNS()?

    - by C.W.Holeman II
    What is jQuery for Document.createElementNS()? function emleGraphicToSvg(aGraphicNode) { var lu = function luf(aPrefix){ switch (aPrefix){ case 'xhtml': return 'http://www.w3.org/1999/xhtml'; case 'math': return 'http://www.w3.org/1998/Math/MathML'; case 'svg': return 'http://www.w3.org/2000/svg'; } return ''; }; var svg = document.evaluate("svg:svg", aGraphicNode, lu, XPathResult.FIRST_ORDERED_NODE_TYPE, null). singleNodeValue; $(svg).children().remove(); rect = document.createElementNS(lu('svg'), "rect"); rect.setAttribute("x", "35"); rect.setAttribute("y", "25"); rect.setAttribute("width", "200"); rect.setAttribute("height", "50"); rect.setAttribute("class", "emleGraphicOutline"); svg.appendChild(rect); } The code is a simplified fragment from Emle - Electronic Mathematics Laboratory Equipment JavaScript file emle_lab.js. The Look-Up-Function, luf(), maps a complete reference to a shorten name for the namespace in the XPath string and createElementNS(). The existing svg:svg is located, removed and replaced by a new rectangle.

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  • Calculate distances and sort them

    - by Emir
    Hi guys, I wrote a function that can calculate the distance between two addresses using the Google Maps API. The addresses are obtained from the database. What I want to do is calculate the distance using the function I wrote and sort the places according to the distance. Just like "Locate Store Near You" feature in online stores. I'm going to specify what I want to do with an example: So, lets say we have 10 addresses in database. And we have a variable $currentlocation. And I have a function called calcdist(), so that I can calculate the distances between 10 addresses and $currentlocation, and sort them. Here is how I do it: $query = mysql_query("SELECT name, address FROM table"); while ($write = mysql_fetch_array($query)) { $distance = array(calcdist($currentlocation, $write["address"])); sort($distance); for ($i=0; $i<1; $i++) { echo "<tr><td><strong>".$distance[$i]." kms</strong></td><td>".$write['name']."</td></tr>"; } } But this doesn't work very well. It doesn't sort the numbers. Another challenge: How can I do this in an efficient way? Imagine there are infinite numbers of addresses; how can I sort these addresses and page them?

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  • PNG Textures not loading on HTC desire

    - by Matthew Tatum
    Hi I'm developing a game for android using OpenGL es and have hit a problem: My game loads fine in the emulator (windows xp and vista from eclipse), it also loads fine on a T-Mobile G2 (HTC Hero) however when I load it on my new HTC Desire none of the textures appear to load correctly (or at all). I'm suspecting the BitmapFactory.decode method although I have no evidence that that is the problem. All of my textures are power of 2 and JPG textures seem to load (although they don't look great quality) but anything that is GIF or PNG just doesn't load at all except for a 2x2 red square which loads fine and one texture that maps to a 3d object but seems to fill each triangle of the mesh with the nearest colour). This is my code for loading images: AssetManager am = androidContext.getAssets(); BufferedInputStream is = null; try { is = new BufferedInputStream(am.open(fileName)); Bitmap bitmap; bitmap = BitmapFactory.decodeStream(is); GLUtils.texImage2D(GL10.GL_TEXTURE_2D, 0, bitmap, 0); bitmap.recycle(); } catch(IOException e) { Logger.global.log(Level.SEVERE, e.getLocalizedMessage()); } finally { try { is.close(); } catch(Exception e) { // Ignore. } } thanks

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  • WCF publish/subscribe service, and ASP.NET MVC client

    - by d3j4vu
    I managed to develop a custom WCF service, using the publish / subscribe model, and hosted inside a managed windows service. Everything's working. I developed an interface as the service contract implementing a method definition marked as a non-one way operation contract (OperationContract(IsOneWay = false)]. This, to make possible returns an instance of a custom class derived from System.Web.Mvc.ActionResult. In the MVC app, event fires ok. It wraps inside an action method, (just the one defined in the interface), but, and this is my current problem, i believe that something relative to the execution context of the windows service (and the hosted wcf counterpart) blocks the execution of the action method in the MVC app. This is what i have until now (some pieces ripped off just to be more clear): /// Method definition for the contract's service. Maps to a MVC ActionMethod. [OperationContract(IsOneWay = false)] ActionResult Imagen(string data, CustomActionResult result); The class to hold an ActionResult derived class instance: public class ServiceEventArgsMvc : ServiceEventArgs { /// <summary> /// /// </summary> public CustomActionResult Result { get; set; } } And the code in the MVC client app: /// <summary> /// Just a simple class to hold an abstract ActionResult derived class instance. /// </summary> public ActionResult Image(string data, CustomActionResult result) { ViewData["data"] = data; return View(); } Ok. ActionMethod sucessfully executes...but when it's done (and usually expected obtain a reditection to a View named Image, like the action method), the WCF service throws a Timeout exception, making clear that he's still waiting for a response from the MVC client. The response never arrives, so the MVC app never finish his work (redirect to the "Image" view as expected). Any ideas?. Guess i'm missing something very simple, but i don't know what it could be. This is drivin' me nuts.

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  • Composing adaptors in Boost::range

    - by bruno nery
    I started playing with Boost::Range in order to have a pipeline of lazy transforms in C++]1. My problem now is how to split a pipeline in smaller parts. Suppose I have: int main(){ auto map = boost::adaptors::transformed; // shorten the name auto sink = generate(1) | map([](int x){ return 2*x; }) | map([](int x){ return x+1; }) | map([](int x){ return 3*x; }); for(auto i : sink) std::cout << i << "\n"; } And I want to replace the first two maps with a magic_transform, i.e.: int main(){ auto map = boost::adaptors::transformed; // shorten the name auto sink = generate(1) | magic_transform() | map([](int x){ return 3*x; }); for(auto i : sink) std::cout << i << "\n"; } How would one write magic_transform? I looked up Boost::Range's documentation, but I can't get a good grasp of it.

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  • Android Linear Layout steching

    - by Maffo
    Hi, I think that's a rather simple Question but I don't get it the way I want it to. I Want do do a Linear Layout in Android with 3 areas. The Top area should have a fixed height, fill_parent width. The second, below the first, should use all the room available, fill_parent width. The third, below the second, should have fixed height, fill_parent width. Here is what i got: <?xml version="1.0" encoding="utf-8"?> <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="fill_parent" android:layout_height="fill_parent" android:orientation="vertical" android:gravity="bottom" android:background="#ff63a920"> <LinearLayout android:id="@+id/top_bar" android:layout_width="fill_parent" android:layout_height="32dp" > </LinearLayout> <com.google.android.maps.MapView android:id="@+id/mymapView" android:layout_width="fill_parent" android:layout_height="fill_parent" android:enabled="true" android:clickable="true" /> <LinearLayout android:id="@+id/bottombar" android:layout_width="fill_parent" android:layout_height="32dp" > </LinearLayout> </LinearLayout> The Problem is, that the mapview in the middle ist too big, so it pushes out the topbar. I Hope you can help me.

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  • How to speed-up a simple method (preferably without changing interfaces or data structures)?

    - by baol
    I have some data structures: all_unordered_m is a big vector containing all the strings I need (all different) ordered_m is a small vector containing the indexes of a subset of the strings (all different) in the former vector position_m maps the indexes of objects from the first vector to their position in the second one. The string_after(index, reverse) method returns the string referenced by ordered_m after all_unordered_m[index]. ordered_m is considered circular, and is explored in natural or reverse order depending on the second parameter. The code is something like the following: struct ordered_subset { // [...] std::vector<std::string>& all_unordered_m; // size = n >> 1 std::vector<size_t> ordered_m; // size << n std::tr1::unordered_map<size_t, size_t> position_m; const std::string& string_after(size_t index, bool reverse) const { size_t pos = position_m.find(index)->second; if(reverse) pos = (pos == 0 ? orderd_m.size() - 1 : pos - 1); else pos = (pos == ordered.size() - 1 ? 0 : pos + 1); return all_unordered_m[ordered_m[pos]]; } }; Given that: I do need all of the data-structures for other purposes; I cannot change them because I need to access the strings: by their id in the all_unordered_m; by their index inside the various ordered_m; I need to know the position of a string (identified by it's position in the first vector) inside ordered_m vector; I cannot change the string_after interface without changing most of the program. How can I speed up the string_after method that is called billions of times and is eating up about 10% of the execution time?

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  • How to speed-up a simple method? (possibily without changing interfaces or data structures)

    - by baol
    Hello. I have some data structures: all_unordered_mordered_m is a big vector containing all the strings I need (all different) ordered_m is a small vector containing the indexes of a subset of the strings (all different) in the former vector position_m maps the indexes of objects from the first vector to their position in the second one. The string_after(index, reverse) method returns the string referenced by ordered_m after all_unordered_m[index]. ordered_m is considered circular, and is explored in natural or reverse order depending on the second parameter. The code is something like the following: struct ordered_subset { // [...] std::vector<std::string>& all_unordered_m; // size = n >> 1 std::vector<size_t> ordered_m; // size << n std::map<size_t, size_t> position_m; // positions of strings in ordered_m const std::string& string_after(size_t index, bool reverse) const { size_t pos = position_m.find(index)->second; if(reverse) pos = (pos == 0 ? orderd_m.size() - 1 : pos - 1); else pos = (pos == ordered.size() - 1 ? 0 : pos + 1); return all_unordered_m[ordered_m[pos]]; } }; Given that: I do need all of the data-structures for other purposes; I cannot change them because I need to access the strings: by their id in the all_unordered_m; by their index inside the various ordered_m; I need to know the position of a string (identified by it's position in the first vector) inside ordered_m vector; I cannot change the string_after interface without changing most of the program. How can I speed up the string_after method that is called billions of times and is eating up about 10% of the execution time?

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  • Fastest reliable way for Clojure (Java) and Ruby apps to communicate

    - by jkndrkn
    Hi There, We have cloud-hosted (RackSpace cloud) Ruby and Java apps that will interact as follows: Ruby app sends a request to Java app. Request consists of map structure containing strings, integers, other maps, and lists (analogous to JSON). Java app analyzes data and sends reply to Ruby App. We are interested in evaluating both messaging formats (JSON, Buffer Protocols, Thrift, etc.) as well as message transmission channels/techniques (sockets, message queues, RPC, REST, SOAP, etc.) Our criteria: Short round-trip time. Low round-trip-time standard deviation. (We understand that garbage collection pauses and network usage spikes can affect this value). High availability. Scalability (we may want to have multiple instances of Ruby and Java app exchanging point-to-point messages in the future). Ease of debugging and profiling. Good documentation and community support. Bonus points for Clojure support. What combination of message format and transmission method would you recommend? Why? I've gathered here some materials we have already collected for review: Comparison of various java serialization options Comparison of Thrift and Protocol Buffers (old) Comparison of various data interchange formats Comparison of Thrift and Protocol Buffers Fallacies of Protocol Buffers RPC features Discussion of RPC in the context of AMQP (Message-Queueing) Comparison of RPC and message-passing in distributed systems (pdf) Criticism of RPC from perspective of message-passing fan Overview of Avro from Ruby programmer perspective

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  • Passing the Class<T> in java of a generic list?

    - by Rob Stevenson-Leggett
    I have a method for reading JSON from a service, I'm using Gson to do my serialization and have written the following method using type parameters. public T getDeserializedJSON(Class<T> aClass,String url) { Reader r = getJSONDataAsReader(url); Gson gson = new Gson(); return gson.fromJson(r, aClass); } I'm consuming json which returns just an array of a type e.g. [ { "prop":"value" } { "prop":"value" } ] I have a java class which maps to this object let's call it MyClass. However to use my method I need to do this: RestClient<ArrayList<MyClass>> restClient = new RestClient<ArrayList<MyClass>>(); ArrayList<MyClass> results = restClient.getDeserializedJSON(ArrayList<MyClass>.class, url); However, I can't figure out the syntax to do it. Passing just ArrayList.class doesn't work. So is there a way I can get rid of the Class parameter or how do I get the class of the ArrayList of MyClass?

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  • android use local service to refresh map UI

    - by urobo
    I don't need a strict code related answer I just need somebody to tell me what I am missing. My application has to retrieve from a web service (xmlrpc) the positions of some users I know and update their position on a MapView. So I decided to use a Service and an Activity extending MapActivity to show results. I thought about two solutions: I ) start the service and make it ask every minute for these positions and send them to the activity as a bundle via intent. (This didn't work out well, since once shown I couldn't find a method to let the activity continue refresh itself until she stop receiving intents+data from the service) II ) Incorporate a thread within the activity which starts the service via context.startService(...) every minute. And the MapUI refresh itself once the service send back an intent and stop itself. (Maybe I will fall in the same problem category as before I haven't tryied yet). I am also giving directions (via maps.google ws) in this way I'd like to refresh only users positions on the map and save the route. What Am I missing do you have any suggestions? related to activities/services internal mechanics, don't know launch modes, use broadcast receivers or intent filters? Thanks in advance

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  • Building a J2EE dev/test setup on a single PC

    - by John
    It's been a while since I did Java work, and even then I was never responsible for starting a large project from the very start... there were test/staging/production systems already running, etc, etc. Now I am looking to start a J2EE project from scratch on my trusty workstation, which has never been used for Java development and runs Windows 7 64bit. First of all, I'll be getting Eclipse. As far as writing the code goes I'm pretty happy. And running it through Eclipse is OK, but what I'd really want is to have a VM running MySQL and TomCat on which I can properly deploy my project and run/debug it 'remotely' from my dev PC. And I guess this should be done using Ant instead of letting Eclipse build the WAR for me, so that I don't end up with a dependence on Eclipse. I'm certain Eclipse can do this, so you hit a button and it runs Ant scripts, deploys and debugs for instance, but very hazy on it. Are there any good guides on this? I don't want to be taught Java, or even Ant, but rather the 'glue' parts like getting my test VM up and running under Windows, getting a build/test/deploy/run pipeline running through Eclipse, etc. One point, I only plan to use Windows... hosting a Windows VM on my Windwos desktop. And while I can use command-line tools like ant/svn, I'm much more a GUI person who loves IDE integration... I'd rather this didn't end up an argument about Linux or Vi, etc! I am looking for free, but am a MAPS subscriber, and run Win7 Ultimate in case that makes a difference as far as free VM solutions.

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  • Finding out the windows group by virtue of which a user is able to access a database in sql server?

    - by Raghu Dodda
    There is a SQL Server 2005 database with mixed-mode authentication. Among others, we have the following logins on the server: our-domain\developers-group-1, and our-domain\developers-group-2 which are AD groups. The our-domain\developer-group-2 is added to the sysadmin role on the server, by virture of which all domain users of that group can access any database as SQL Server implictly maps the sysadmin role to the dbo user in each database. There are two users our-domain\good-user and our-domain\bad-user The issue is the following: Both the good-user and the bad-user have the exact same AD group memberships. They are both members of our-domain\developers-group-1 and our-domain\developers-group-2. The good-user is able to access all the databases, and the bad-user is not. The bad-user is able to login, but he is unable access any databases. By the way, I am the good-user. How do I go about finding out why? Here's what I tried so far: When I do print current_user, I get dbo When I do print system_user, I get my-domain\good-user When I do select * from fn_my_permissions(NULL, 'SERVER'), I see permissions. But if do execute as user='my-domain\good-user'; select * from fn_my_permissions(NULL, 'SERVER'), I dont see any permisisons. And When I do, execute as user='my-domain\bad-user'; select * from fn_my_permissions(NULL, 'SERVER'), I dont see any permisisons. Also, I was wondering if there is a sql command that will tell me, "hey! the current database user is able to access this database because he is a member such-and-such ad-group, which is a login that is mapped to such-and-such user in this database".

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  • Entity Framework does not map 2 columns from a SqlQuery calling a stored procedure

    - by user1783530
    I'm using Code First and am trying to call a stored procedure and have it map to one of my classes. I created a stored procedure, BOMComponentChild, that returns details of a Component with information of its hierarchy in PartsPath and MyPath. I have a class for the output of this stored procedure. I'm having an issue where everything except the two columns, PartsPath and MyPath, are being mapped correctly with these two properties ending up as Nothing. I searched around and from my understanding the mapping bypasses any Entity Framework name mapping and uses column name to property name. The names are the same and I'm not sure why it is only these two columns. The last part of the stored procedure is: SELECT t.ParentID ,t.ComponentID ,c.PartNumber ,t.PartsPath ,t.MyPath ,t.Layer ,c.[Description] ,loc.LocationID ,loc.LocationName ,CASE WHEN sup.SupplierID IS NULL THEN 1 ELSE sup.SupplierID END AS SupplierID ,CASE WHEN sup.SupplierName IS NULL THEN 'Scinomix' ELSE sup.SupplierName END AS SupplierName ,c.Active ,c.QA ,c.IsAssembly ,c.IsPurchasable ,c.IsMachined ,t.QtyRequired ,t.TotalQty FROM BuildProducts t INNER JOIN [dbo].[BOMComponent] c ON c.ComponentID = t.ComponentID LEFT JOIN [dbo].[BOMSupplier] bsup ON bsup.ComponentID = t.ComponentID AND bsup.IsDefault = 1 LEFT JOIN [dbo].[LookupSupplier] sup ON sup.SupplierID = bsup.SupplierID LEFT JOIN [dbo].[LookupLocation] loc ON loc.LocationID = c.LocationID WHERE (@IsAssembly IS NULL OR IsAssembly = @IsAssembly) ORDER BY t.MyPath and the class it maps to is: Public Class BOMComponentChild Public Property ParentID As Nullable(Of Integer) Public Property ComponentID As Integer Public Property PartNumber As String Public Property MyPath As String Public Property PartsPath As String Public Property Layer As Integer Public Property Description As String Public Property LocationID As Integer Public Property LocationName As String Public Property SupplierID As Integer Public Property SupplierName As String Public Property Active As Boolean Public Property QA As Boolean Public Property IsAssembly As Boolean Public Property IsPurchasable As Boolean Public Property IsMachined As Boolean Public Property QtyRequired As Integer Public Property TotalQty As Integer Public Property Children As IDictionary(Of String, BOMComponentChild) = New Dictionary(Of String, BOMComponentChild) End Class I am trying to call it like this: Me.Database.SqlQuery(Of BOMComponentChild)("EXEC [BOMComponentChild] @ComponentID, @PathPrefix, @IsAssembly", params).ToList() When I run the stored procedure in management studio, the columns are correct and not null. I just can't figure out why these won't map as they are the important information in the stored procedure. The types for PartsPath and MyPath are varchar(50).

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  • C++: Vector of objects vs. vector of pointers to new objects?

    - by metamemetics
    Hello, I am seeking to improve my C++ skills by writing a sample software renderer. It takes objects consisting of points in a 3d space and maps them to a 2d viewport and draws circles of varying size for each point in view. Which is better: class World{ vector<ObjectBaseClass> object_list; public: void generate(){ object_list.clear(); object_list.push_back(DerivedClass1()); object_list.push_back(DerivedClass2()); or... class World{ vector<ObjectBaseClass*> object_list; public: void generate(){ object_list.clear(); object_list.push_back(new DerivedClass1()); object_list.push_back(new DerivedClass2()); ?? Would be using pointers in the 2nd example to create new objects defeat the point of using vectors, because vectors automatically call the DerivedClass destructors in the first example but not in the 2nd? Are pointers to new objects necessary when using vectors because they handle memory management themselves as long as you use their access methods? Now let's say I have another method in world: void drawfrom(Viewport& view){ for (unsigned int i=0;i<object_list.size();++i){ object_list.at(i).draw(view); } } When called this will run the draw method for every object in the world list. Let's say I want derived classes to be able to have their own versions of draw(). Would the list need to be of pointers then in order to use the method selector (-) ?

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  • Question about singleton property

    - by Jack
    I'm reading the java tutorial for enums located here and have a question: http://java.sun.com/j2se/1.5.0/docs/guide/language/enums.html#Card The part i'm confused about is as follows: "The Card class, above, contains a static factory that returns a deck, but there is no way to get an individual card from its rank and suit. Merely exposing the constructor would destroy the singleton property (that only a single instance of each card is allowed to exist). Here is how to write a static factory that preserves the singleton property, using a nested EnumMap: " Now as I understand, changing the original private "Card" constructor to public would allow us to instantiate an unlimited number of copies of a "Card" object with a given suit+rank. The solution as proposed was to create an EnumMap which would store four Maps (one for each suit), which themselves contained 13 Card objects with the rank as their keys. And so now if you wanted to retrieve a specific Card object from the deck, you would just call the "valueOf" method. My question now is, what's the prevent you with calling the valueOf method as many times as you like? Wouldn't that lead to the same problem as making the original private constructor public? Thanks.

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  • Is there a concise way to map a string to an enum in Objective-C?

    - by zekel
    I have a string I want to parse and return an equivalent enum. I need to use the enum type elsewhere, and I think I like how I'm defining the class. The problem is that I don't know a good way to check the string against the enum values without being redundant about the order of the enums. typedef enum { ZZColorRed, ZZColorGreen, ZZColorBlue, } ZZColorType; - (ZZColorType)parseColor:(NSString *)inputString { // inputString will be @"red", @"green", or @"blue" (trust me) // how can I turn that into ZZColorRed, etc. without // redefining their order like this? NSArray *colors = [NSArray arrayWithObjects:@"red", @"green", @"blue", nil]; return [colors indexOfObject:inputString]; } In Python, I'd probably do something like the following, although to be honest I'm not in love with that either. ## maps url text -> constant string RED_CONSTANT = 1 BLUE_CONSTANT = 2 GREEN_CONSTANT = 3 TYPES = { 'red': RED_CONSTANT, 'green': GREEN_CONSTANT, 'blue': BLUE_CONSTANT, } def parseColor(inputString): return TYPES.get(inputString) ps. I know there are color constants in Cocoa, this is just an example.

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  • Getting the eventargs of registered events

    - by Bjorn Vdkerckhove
    i'm new with maps and openlayers, but i'm playing around with openlayers because i'll need mapfunctionality in my next project. The map is an image (because it's a drawn map of a medieval town). I found how i can register events, and it's working. But the problem is, that the "eventargs" is not working as in the examples i found. In one of the examples they are getting the x and y values after the users panned like this: map.events.register('moveend', map, function (e) { alert(e.xy); }); If i try this in visual studio, e doesn't have a 'xy' property. What am i missing? This is the code i have right now: <script type="text/javascript"> var map, layer; function init() { var windowHeight = $(window).height(); var windowWidth = $(window).width(); var mapdiv = $('#map'); mapdiv.css({width: windowWidth + 'px', height: windowHeight + 'px'}); map = new OpenLayers.Map('map', { maxResolution: 1000 }); layer = new OpenLayers.Layer.Image( 'Globe ESA', '[url]', new OpenLayers.Bounds(-180.0, -12333.5, 21755.5, 90.0), new OpenLayers.Size(windowWidth, windowHeight), { numZoomLevels: 100 }); map.addLayer(layer); nav = new OpenLayers.Control.Navigation(); map.addControl(nav); //events test map.events.register('moveend', map, function (e) { alert(e.xy); }); map.zoomToMaxExtent(); } </script> In the examples of openlayer, they don't use the eventargs, but there must be a way to get the zoomlevel, or the x and y after panning, right? Thank you!

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  • What is the meaning of @ModelAttribute annotation at method argument level?

    - by beemaster
    Spring 3 reference teaches us: When you place it on a method parameter, @ModelAttribute maps a model attribute to the specific, annotated method parameter I don't understand this magic spell, because i sure that model object's alias (key value if using ModelMap as return type) passed to the View after executing of the request handler method. Therefore when request handler method executes the model object's name can't be mapped to the method parameter. To solve this contradiction i went to stackoverflow and found this detailed example. The author of example said: // The "personAttribute" model has been passed to the controller from the JSP It seems, he is charmed by Spring reference... To dispel the charms i deployed his sample app in my environment and cruelly cut @ModelAttribute annotation from method MainController.saveEdit. As result the application works without any changes! So i conclude: the @ModelAttribute annotation is not needed to pass web form's field values to the argument's fields. Then i stuck to the question: what is the mean of @ModelAttribute annotation? If the only mean is to set alias for model object in View, then why this way better than explicitly adding of object to ModelMap?

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  • Encode_JSON Errors in Lasso 8.6.2 After Period of Time

    - by ATP_JD
    We are in the process of converting apps from Lasso 8 to Lasso 9, and as an intermediate step, have upgraded from 8.5.5 to 8.6.2 (which runs alongside 9 on our new box, in different virtual hosts). I am finding that with 8.6.2 we are getting a slew of errors on pages that call encode_json. The weird thing with these errors is that they don't start happening until some period of time after the site starts. Then, some hours later, all encode_json calls begin to fail with error messages like this: An error occurred while processing your request. Error Information Error Message: No tag, type or constant was defined under the name "?????????????????" with arguments: array: (pair: (-find)=([\x{0020}-\x{21}\x{23}-\x{5b}\x{5d}-\x{10fff}])), (r) at: onCompare with params: 'r' at: JSON with params: 'reload', -Options=array: (-Internal) at: JSON with params: @map: (reload)=(false), (tcstring)=(LZU), (timestring)=(10:42 AM&nbsp;&nbsp;&nbsp;1442Z) at: [...].lasso with params: 'pageloadtime'='1383038310' on line: 31 at position: 1 Error Code: -9948 (Yes, those Chinese(?) characters are in the error message.) I have removed the 8.5.5 encode_json tag from LassoStartup, so we are using the correct built-in method. The encode_json method fails for any and all parameters I throw at it from simple strings to arrays of maps. Upon restarting the site, encode_json resumes working for an hour or two, seemingly depending on load. On 8.5.5, we don't have this problem. Does anyone have experience with this issue? Any advice regarding trying the 8.5.5 tag swap encode_json to see if I can override the built-in method? Maybe it will work better? Thanks in advance for your time and assistance. -Justin

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