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  • C#/LINQ: How to define generically a keySelector for a templated class before calling OrderBy

    - by PierrOz
    Hi Folks, I have the following class defined in C# class myClass<T,U> { public T PropertyOne { get; set; } public U PropertyTwo { get; set; } } I need to write a function that reorder a list of myClass objects and takes two other parameters which define how I do this reorder: does my reordering depend on PropertyOne or PropertyTwo and is it ascending or descending. Let's say this two parameters are boolean. With my current knowledge in LINQ, I would write: public IList<myClass<T,U>> ReOrder(IList<myClass<T,U>> myList, bool usePropertyOne, bool ascending) { if (usePropertyOne) { if (ascending) { return myList.OrderBy(o => o.PropertyOne).ToList(); } else { return myList.OrderByDescending(o => o.PropertyOne).ToList(); } } else { if (ascending) { return myList.OrderBy(o => o.PropertyTwo).ToList(); } else { return myList.OrderByDescending(o => o.PropertyTwo).ToList(); } } } What could be a more efficient/elegant way to do that ? How can I declare the Func,TResult keySelector object to reuse when I call either OrderBy or OrderByDescending? I'm interesting in the answer since in my real life, I can have more than two properties.

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  • C# reflection instantiation

    - by NickLarsen
    I am currently trying to create a generic instance factory for which takes an interface as the generic parameter (enforced in the constructor) and then lets you get instantiated objects which implement that interface from all types in all loaded assemblies. The current implementation is as follows:     public class InstantiationFactory     {         protected Type Type { get; set; }         public InstantiationFactory()         {             this.Type = typeof(T);             if (!this.Type.IsInterface)             {                 // is there a more descriptive exception to throw?                 throw new ArgumentException(/* Crafty message */);             }         }         public IEnumerable GetLoadedTypes()         {             // this line of code found in other stack overflow questions             var types = AppDomain.CurrentDomain.GetAssemblies()                 .SelectMany(a = a.GetTypes())                 .Where(/* lambda to identify instantiable types which implement this interface */);             return types;         }         public IEnumerable GetImplementations(IEnumerable types)         {             var implementations = types.Where(/* lambda to identify instantiable types which implement this interface */                 .Select(x = CreateInstance(x));             return implementations;         }         public IEnumerable GetLoadedImplementations()         {             var loadedTypes = GetLoadedTypes();             var implementations = GetImplementations(loadedTypes);             return implementations;         }         private T CreateInstance(Type type)         {             T instance = default(T);             var constructor = type.GetConstructor(Type.EmptyTypes);             if (/* valid to instantiate test */)             {                 object constructed = constructor.Invoke(null);                 instance = (T)constructed;             }             return instance;         }     } It seems useful to me to have my CreateInstance(Type) function implemented as an extension method so I can reuse it later and simplify the code of my factory, but I can't figure out how to return a strongly typed value from that extension method. I realize I could just return an object:     public static class TypeExtensions     {         public object CreateInstance(this Type type)         {             var constructor = type.GetConstructor(Type.EmptyTypes);             return /* valid to instantiate test */ ? constructor.Invoke(null) : null;         }     } Is it possible to have an extension method create a signature per instance of the type it extends? My perfect code would be this, which avoids having to cast the result of the call to CreateInstance():     Type type = typeof(MyParameterlessConstructorImplementingType);     MyParameterlessConstructorImplementingType usable = type.CreateInstance();

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  • Object Oriented Programming in AS3

    - by Jordan
    I'm building a game in as3 that has balls moving and bouncing off the walls. When the user clicks an explosion appears and any ball that hits that explosion explodes too. Any ball that then hits that explosion explodes and so on. My question is what would be the best class structure for the balls. I have a level system to control levels and such and I've already come up with working ways to code the balls. Here's what I've done. My first attempt was to create a class for Movement, Bounce, Explosion and finally Orb. These all extended each other in the order I just named them. I got it working but having Bounce extend Movement and Explosion extend Bounce, it just doesn't seem very object oriented because what if I wanted to add a box class that didn't move, but did explode? I would need a separate class for that explosion. My second attempt was to create Movement, Bounce and Explosion without extending anything. Instead I passed in a reference to the Orb class to each. Then the class stores that reference and does what it needs to do based on events that are dispatched by the Orb such as update, which was broadcast from Orb every enter frame. This would drive the movement and bounce and also the explosion when the time came. This attempt worked as well but it just doesn't seem right. I've also thought about using Interfaces but because they are more of an outline for classes, I feel like code reuse goes out the window as each class would need its own code for a specific task even if that task is exactly the same. I feel as if I'm searching for some form of multiple inheritance for classes that as3 does not support. Can someone explain to me a better way of doing what I'm attempting to do? Am I being to "Object Oriented" by having classed for Movement, Bounce, Explosion and Orb? Are Interfaces the way to go? Any feedback is appreciated!

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  • Do I need Response.End() in ASP.Net 2.0

    - by Hamish Grubijan
    Hi, I am just starting with ASP.Net. I copied a ex-co-worker's code (from .Net 1.1 era) and it has a Response.End(); in case of an error. There is also a: catch (Exception ex) { Response.Write(ex.Message); Response.End(); } at the end of Page_Load(object sender, System.EventArgs e) which always appends "Thread was aborted." or something like that at the end. I suspect that this worked differently before, or the error conditions were not tested very well. Anyhow, I was able to stop using Response.End(); in case when I do not like the GET parameters, and use return; instead. It seemed to do the right think in a simple case. Is this Ok in general? There are some problems with the code I copied, but I do not want to do a rewrite; I just want to get it running first and find wrinkles later. The Response.End(); caused a mental block for me, however, so I want to figure it out. I want to keep the catch all clause just in case, at least for now. I could also end the method with: catch (System.Threading.ThreadAbortException) { Response.End(); } catch (Exception ex) { Response.Write(ex.Message); Response.End(); } but that just seems extremely stupid, once you think about all of the exceptions being generated. Please give me a few words of wisdom. Feel free to ask if something is not clear. Thanks! P.S. Ex-coworker was not fired and is a good coder - one more reason to reuse his example.

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  • Optimal two variable linear regression SQL statement

    - by Dave Jarvis
    Problem Am looking to apply the y = mx + b equation (where m is SLOPE, b is INTERCEPT) to a data set, which is retrieved as shown in the SQL code. The values from the (MySQL) query are: SLOPE = 0.0276653965651912 INTERCEPT = -57.2338357550468 SQL Code SELECT ((sum(t.YEAR) * sum(t.AMOUNT)) - (count(1) * sum(t.YEAR * t.AMOUNT))) / (power(sum(t.YEAR), 2) - count(1) * sum(power(t.YEAR, 2))) as SLOPE, ((sum( t.YEAR ) * sum( t.YEAR * t.AMOUNT )) - (sum( t.AMOUNT ) * sum(power(t.YEAR, 2)))) / (power(sum(t.YEAR), 2) - count(1) * sum(power(t.YEAR, 2))) as INTERCEPT FROM (SELECT D.AMOUNT, Y.YEAR FROM CITY C, STATION S, YEAR_REF Y, MONTH_REF M, DAILY D WHERE -- For a specific city ... -- C.ID = 8590 AND -- Find all the stations within a 5 unit radius ... -- SQRT( POW( C.LATITUDE - S.LATITUDE, 2 ) + POW( C.LONGITUDE - S.LONGITUDE, 2 ) ) <15 AND -- Gather all known years for that station ... -- S.STATION_DISTRICT_ID = Y.STATION_DISTRICT_ID AND -- The data before 1900 is shaky; and insufficient after 2009. -- Y.YEAR BETWEEN 1900 AND 2009 AND -- Filtered by all known months ... -- M.YEAR_REF_ID = Y.ID AND -- Whittled down by category ... -- M.CATEGORY_ID = '001' AND -- Into the valid daily climate data. -- M.ID = D.MONTH_REF_ID AND D.DAILY_FLAG_ID <> 'M' GROUP BY Y.YEAR ORDER BY Y.YEAR ) t Data The data is visualized here: Questions How do I return the y value against all rows without repeating the same query to collect and collate the data? That is, how do I "reuse" the list of t values? How would you change the query to eliminate outliers (at an 85% confidence interval)? The following results (to calculate the start and end points of the line) appear incorrect. Why are the results off by ~10 degrees (e.g., outliers skewing the data)? (1900 * 0.0276653965651912) + (-57.2338357550468) = -4.66958228 (2009 * 0.0276653965651912) + (-57.2338357550468) = -1.65405406 I would have expected the 1900 result to be around 10 (not -4.67) and the 2009 result to be around 11.50 (not -1.65). Thank you!

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  • Generalizing Fibonacci sequence with SICStus Prolog

    - by Christophe Herreman
    I'm trying to find a solution for a query on a generalized Fibonacci sequence (GFS). The query is: are there any GFS that have 885 as their 12th number? The initial 2 numbers may be restricted between 1 and 10. I already found the solution to find the Nth number in a sequence that starts at (1, 1) in which I explicitly define the initial numbers. Here is what I have for this: fib(1, 1). fib(2, 1). fib(N, X) :- N #> 1, Nmin1 #= N - 1, Nmin2 #= N - 2, fib(Nmin1, Xmin1), fib(Nmin2, Xmin2), X #= Xmin1 + Xmin2. For the query mentioned I thought the following would do the trick, in which I reuse the fib method without defining the initial numbers explicitly since this now needs to be done dynamically: fib2 :- X1 in 1..10, X2 in 1..10, fib(1, X1), fib(2, X2), fib(12, 885). ... but this does not seem to work. Is it not possible this way to define the initial numbers, or am I doing something terribly wrong? I'm not asking for the solution, but any advice that could help me solve this would be greatly appreciated.

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  • Extension methods for encapsulation and reusability

    - by tzaman
    In C++ programming, it's generally considered good practice to "prefer non-member non-friend functions" instead of instance methods. This has been recommended by Scott Meyers in this classic Dr. Dobbs article, and repeated by Herb Sutter and Andrei Alexandrescu in C++ Coding Standards (item 44); the general argument being that if a function can do its job solely by relying on the public interface exposed by the class, it actually increases encapsulation to have it be external. While this confuses the "packaging" of the class to some extent, the benefits are generally considered worth it. Now, ever since I've started programming in C#, I've had a feeling that here is the ultimate expression of the concept that they're trying to achieve with "non-member, non-friend functions that are part of a class interface". C# adds two crucial components to the mix - the first being interfaces, and the second extension methods: Interfaces allow a class to formally specify their public contract, the methods and properties that they're exposing to the world. Any other class can choose to implement the same interface and fulfill that same contract. Extension methods can be defined on an interface, providing any functionality that can be implemented via the interface to all implementers automatically. And best of all, because of the "instance syntax" sugar and IDE support, they can be called the same way as any other instance method, eliminating the cognitive overhead! So you get the encapsulation benefits of "non-member, non-friend" functions with the convenience of members. Seems like the best of both worlds to me; the .NET library itself providing a shining example in LINQ. However, everywhere I look I see people warning against extension method overuse; even the MSDN page itself states: In general, we recommend that you implement extension methods sparingly and only when you have to. So what's the verdict? Are extension methods the acme of encapsulation and code reuse, or am I just deluding myself?

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  • Getting the name of a child class in the parent class (static context)

    - by Benoit Myard
    Hi everybody, I'm building an ORM library with reuse and simplicity in mind; everything goes fine except that I got stuck by a stupid inheritance limitation. Please consider the code below: class BaseModel { /* * Return an instance of a Model from the database. */ static public function get (/* varargs */) { // 1. Notice we want an instance of User $class = get_class(parent); // value: bool(false) $class = get_class(self); // value: bool(false) $class = get_class(); // value: string(9) "BaseModel" $class = __CLASS__; // value: string(9) "BaseModel" // 2. Query the database with id $row = get_row_from_db_as_array(func_get_args()); // 3. Return the filled instance $obj = new $class(); $obj->data = $row; return $obj; } } class User extends BaseModel { protected $table = 'users'; protected $fields = array('id', 'name'); protected $primary_keys = array('id'); } class Section extends BaseModel { // [...] } $my_user = User::get(3); $my_user->name = 'Jean'; $other_user = User::get(24); $other_user->name = 'Paul'; $my_user->save(); $other_user->save(); $my_section = Section::get('apropos'); $my_section->delete(); Obviously, this is not the behavior I was expecting (although the actual behavior also makes sense).. So my question is if you guys know of a mean to get, in the parent class, the name of child class.

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  • User preferences using SQL and JavaScript

    - by Shyam
    Hi, I am using Server Side JavaScript - yes, I am actually using Server Side JavaScript. To complexify things even more, I use Oracle as a backend database (10g). With some crazy XSLT and mutant-like HTML generation, I can build really fancy web forms - yes, I am aware of Rails and other likewise frameworks and I choose the path of horror instead. I have no JQuery or other fancy framework at my disposal, just plain ol' JavaScript that should be supported by the underlying engine called Mozilla Rhino. Yes, it is insane and I love it. So, I have a bunch of tables at my disposal and some of them are filled with associative keys that link to values. As I am a people pleaser, I want to add some nifty user-preference driven solutions. My users have all an unique user_id and this user_id is available during the entire session. My initial idea is to have a user preference table, where I have "three" columns: user_id, feature and pref_string. Using a delimiter, such as : or - (haven't thought about a suitable one yet), I could like store a bunch of preferences as a list and store its elements inside an array using the .split-method (similar like the PHP-explode function). The feature column could be like the table name or some identifier for the "feature" i want to link preferences too. I hate hardcoding objects, especially as I want to be able to back these up and reuse this functionality application-wide. Of course I would love better ideas, just keep in mind I cannot just add a library that easily. These preferences could be like "joined" to the table, so I can query it and use its values. I hope it doesn't sounds too complex, because well.. its basically something really simple I need. Thanks!

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  • Suggest the way to design several classes

    - by Oleg Tarasenko
    Hi, I'm building simple application on as3. Kind of starship game. What I want to do is to create several different star ships. Each one should have different images (different look), different sets of animation (e.g. when it's flying, burning, damaged), different kind of weapon and also different controllers (e.g. one can be managed by user, another one by computer, and I want to be able to reuse same ships for AI controller as well as for users controls). Each ship is created in the following way: Create entity Add spatial Add renderers Add other components.... ...... n. init the ship So what I am trying to do: 1) Create StarShip superclass, to store HP (as every ship has it), store spatial (same reason) 2) Create inherited class for any other ship... (It will contain renderer - (responsible for display part), weapon, set of animations), etc What do you think about such way of composition? Maybe it's better to place everything in super class, and then just create instances using long, long, long constructors like: StarShip(hp:HP, animations:DICT, weapon:Weapon, ....) Need advice

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  • C#/.NET library for source code formatting, like the one used by Stack Overflow?

    - by Lasse V. Karlsen
    I am writing a command line tool to convert Markdown text to html output, which seems easy enough. However, I am wondering how to get nice syntax coloring for embedded code blocks, like the one used by Stack Overflow. Does anyone know either: What library StackOverflow is using or if there's a library out there that I can easily reuse? Basically it would need to have some of the same "intelligence" found in the one that Stack Overflow uses, by basically doing a best-attempt at figuring out the language in use to pick the right keywords. Basically, what I want is for my own program to handle a block like the following: if (a == 0) return true; if (a == 1) return false; // fall-back Markdown Sharp, the library I'm using, by default outputs the above as a simple pre/code html block, with no syntax coloring. I'd like the same type of handling as the formatting on Stack Overflow does, the above contains blue "return" keywords for example. Or, hmm, after checking the source of this Stack Overflow page after adding the code example, I notice that it too is formatted like a simple pre/code block. Is it pure javascript-magic at works here, so perhaps there's no such library? If there's no library that will automagically determine a possible language by the keywords used, is there one that would work if I explicitly told it the language? Since this is "my" markdown-commandline-tool, I can easily add syntax if I need to.

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  • WCF service reference namespace differs from original

    - by Thorarin
    I'm having a problem regarding namespaces used by my service references. I have a number of WCF services, say with the namespace MyCompany.Services.MyProduct (the actual namespaces are longer). As part of the product, I'm also providing a sample C# .NET website. This web application uses the namespace MyCompany.MyProduct. During initial development, the service was added as a project reference to the website and uses directly. I used a factory pattern that returns an object instance that implements MyCompany.Services.MyProduct.IMyService. So far, so good. Now I want to change this to use an actual service reference. After adding the reference and typing MyCompany.Services.MyProduct in the namespace textbox, it generates classes in the namespace MyCompany.MyProduct.MyCompany.Services.MyProduct. BAD! I don't want to have to change using directives in several places just because I'm using a proxy class. So I tried prepending the namespace with global::, but that is not accepted. Note that I hadn't even deleted the original assembly references yet, and "reuse types" is enabled, but no reusing was done, apparently. However, I don't want to keep the assembly references around in my sample website for it to work anyway. The only solution I've come up with so far is setting the default namespace for my web application to MyCompany (because it cannot be empty), and adding the service reference as Services.MyProduct. Suppose that a customer wants to use my sample website as a starting point, and they change the default namespace to OtherCompany.Whatever, this will obviously break my workaround. Is there a good solution to this problem? To summarize: I want to generate a service reference proxy in the original namespace, without referencing the assembly. Note: I have seen this question, but there was no solution provided that is acceptable for my use case. Edit: As John Saunders suggested, I've submitted some feedback to Microsoft about this: Feedback item @ Microsoft Connect

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  • UISlider won't display

    - by user290295
    I have been having a lot of difficulty adding custom track images to a UISlider. Whenever I do this, whether to a nib created UISlider or a hand programmed UISlider the slider refuses to display. Also, I even commented the track image code out below and the UISlider still refuses to display. There are other nib created sliders in the controlView that display and function fine. if (![self loadView:keyboardControlView intoSuperview:controlView withNib:@"KeyboardControl"]) { NSLog(@"Could not load controlView from nib into synthControlView"); } // nibSlider is an outlet to a UISlider in the above loaded nib file CGRect sliderFrame = nibSlider.frame; float sliderMinimum = nibSlider.minimumValue; float sliderMaximum = nibSlider.maximumValue; float sliderValue = nibSlider.value; // remove from superview, implicitly releasing UISlider [nibSlider removeFromSuperview]; // reuse pointer to allocate new UISlider using rect obtained from nib nibSlider = [[UISlider alloc] initWithFrame:sliderFrame]; nibSlider.backgroundColor = [UIColor clearColor]; nibSlider.minimumValue = sliderMinimum; nibSlider.maximumValue = sliderMaximum; nibSlider.continuous = YES; nibSlider.value = sliderValue; //[nibSlider setMinimumTrackImage:[[UIImage imageNamed:@"violetslider.png"] //stretchableImageWithLeftCapWidth:5.0 topCapHeight:0.0] forState:UIControlStateNormal]; // //[nibSlider setMaximumTrackImage:[[UIImage imageNamed:@"violetslider.png"] // stretchableImageWithLeftCapWidth:5.0 topCapHeight:0.0] forState:UIControlStateNormal]; [nibSlider addTarget:delegate action:@selector(sliderUpdate:) forControlEvents:UIControlEventValueChanged]; [controlView addSubview:nibSlider]; // do not release here as slider will need to remain cached. push onto a release stack. [nibSlider setNeedsDisplay];

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  • How to use Hibernate SchemaUpdate class with a JPA persistence.xml?

    - by John Rizzo
    I've a main method using SchemaUpdate to display at the console what tables to alter/create and it works fine in my Hibernate project: public static void main(String[] args) throws IOException { //first we prepare the configuration Properties hibProps = new Properties(); hibProps.load(Thread.currentThread().getContextClassLoader().getResourceAsStream("jbbconfigs.properties")); Configuration cfg = new AnnotationConfiguration(); cfg.configure("/hibernate.cfg.xml").addProperties(hibProps); //We create the SchemaUpdate thanks to the configs SchemaUpdate schemaUpdate = new SchemaUpdate(cfg); //The update is executed in script mode only schemaUpdate.execute(true, false); ... I'd like to reuse this code in a JPA project, having no hibernate.cfg.xml file (and no .properties file), but a persistence.xml file (autodetected in the META-INF directory as specified by the JPA spec). I tried this too simple adaptation, Configuration cfg = new AnnotationConfiguration(); cfg.configure(); but it failed with that exception. Exception in thread "main" org.hibernate.HibernateException: /hibernate.cfg.xml not found Has anybody done that? Thanks.

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  • Unit Testing Private Method in Resource Managing Class (C++)

    - by BillyONeal
    I previously asked this question under another name but deleted it because I didn't explain it very well. Let's say I have a class which manages a file. Let's say that this class treats the file as having a specific file format, and contains methods to perform operations on this file: class Foo { std::wstring fileName_; public: Foo(const std::wstring& fileName) : fileName_(fileName) { //Construct a Foo here. }; int getChecksum() { //Open the file and read some part of it //Long method to figure out what checksum it is. //Return the checksum. } }; Let's say I'd like to be able to unit test the part of this class that calculates the checksum. Unit testing the parts of the class that load in the file and such is impractical, because to test every part of the getChecksum() method I might need to construct 40 or 50 files! Now lets say I'd like to reuse the checksum method elsewhere in the class. I extract the method so that it now looks like this: class Foo { std::wstring fileName_; static int calculateChecksum(const std::vector<unsigned char> &fileBytes) { //Long method to figure out what checksum it is. } public: Foo(const std::wstring& fileName) : fileName_(fileName) { //Construct a Foo here. }; int getChecksum() { //Open the file and read some part of it return calculateChecksum( something ); } void modifyThisFileSomehow() { //Perform modification int newChecksum = calculateChecksum( something ); //Apply the newChecksum to the file } }; Now I'd like to unit test the calculateChecksum() method because it's easy to test and complicated, and I don't care about unit testing getChecksum() because it's simple and very difficult to test. But I can't test calculateChecksum() directly because it is private. Does anyone know of a solution to this problem?

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  • How to apply CSS theme to only a specific jQuery-UI element?

    - by Thierry-Dimitri Roy
    I have a web site already build with my own CSS theme. I'm using jQuery UI "tabs" widget but no CSS from jQuery-UI. Now, I'm trying to add the "Date Picker" widget in one of my page. It would be great if I could reuse jQuery-UI default theme which is just fine. The problem is that the date picker theme is also applied to my tabs CSS. For example the "ui-widget" css properties is applied to both date picker and tabs elements. I can't seem to find a way to apply the css properties to only the date picker. I can't see a "super selector" that only applies to the date picker DIV. What would be the best way to handle this? [EDIT] The datepicker widget is really the problem. I cannot apply CSS style specific to it. Here is the starting code of the DIV that get pops up: <div style="position: absolute; top: 300.4px; left: 149px; display: block;" id="ui-datepicker-div" class="ui-datepicker ui-widget ui-widget-content ui-helper-clearfix ui-corner-all ui-helper-hidden-accessible"><div class="ui-datepicker-header ui-widget-header ui-helper-clearfix ui-corner-all"> As such, I cannot add a super selector. What would be great would be that the date picker widget supports CSS scope. But it does not. I'm stuck manually editing the jQuery CSS file. The Date Picker is currently being refactored. Hopefully the new code will address this issue.

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  • Recursion in prepared statements

    - by Rob
    I've been using PDO and preparing all my statements primarily for security reasons. However, I have a part of my code that does execute the same statement many times with different parameters, and I thought this would be where the prepared statements really shine. But they actually break the code... The basic logic of the code is this. function someFunction($something) { global $pdo; $array = array(); static $handle = null; if (!$handle) { $handle = $pdo->prepare("A STATEMENT WITH :a_param"); } $handle->bindValue(":a_param", $something); if ($handle->execute()) { while ($row = $handle->fetch()) { $array[] = someFunction($row['blah']); } } return $array; } It looked fine to me, but it was missing out a lot of rows. Eventually I realised that the statement handle was being changed (executed with different param), which means the call to fetch in the while loop will only ever work once, then the function calls itself again, and the result set is changed. So I am wondering what's the best way of using PDO prepared statements in a recursive way. One way could be to use fetchAll(), but it says in the manual that has a substantial overhead. The whole point of this is to make it more efficient. The other thing I could do is not reuse a static handle, and instead make a new one every time. I believe that since the query string is the same, internally the MySQL driver will be using a prepared statement anyway, so there is just the small overhead of creating a new handle on each recursive call. Personally I think that defeats the point. Or is there some way of rewriting this?

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  • Using an ORM with a database that has no defined relationships?

    - by Ahmad
    Consider a database(MSSQL 2005) that consists of 100+ tables which have primary keys defined to a certain degree. There are 'relationships' between tables, however these are not enforced with foreign key constraints. Consider the following simplified example of typical types of tables I am dealing with. The are clear relations between the User and City and Province tables. However, they key issues is the inconsistent data types in the tables and naming conventions. User: UserRowId [int] PK Name [varchar(50)] CityId [smallint] ProvinceRowId [bigint] City: CityRowId [bigint] PK CityDescription [varchar(100)] Province: ProvinceId [int] PK ProvinceDesc [varchar(50)] I am considering a rewrite of the application (in ASP.net MVC) that uses this data source as is similar in design to MVC storefront. However I am going through a proof of concept phase and this is one of the stumbling blocks I have come across. What are my options in terms of ORM choice that can be easily used and why? Should I even be considering an ORM? (The reason I ask this is that most explanations and tutorials all work with relatively cleanly designed existing databases, or newly created ones when compared to mine. I am thus having a very hard time trying to find a way forward with this problem) There is a huge amount of existing SQL queries, would a datamappper(eg IBatis.net) be more suitable since we could easily modify them to work and reuse the investment already made? I have found this question on SO which indicates to me that an ORM can be used - however I get the impression that this a question of mapping? Note: at the moment, the object model is not clearly defined as it was non-existent. The existing system pretty much did almost everything in SQL or consisted of overly complicated, and numerous queries to complete fucntionality. I am pretty much a noob and have zero experience around ORMs and MVC - so this an awesome learning curve I am on.

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  • Linux C debugging library to detect memory corruptions

    - by calandoa
    When working sometimes ago on an embedded system with a simple MMU, I used to program dynamically this MMU to detect memory corruptions. For instance, at some moment at runtime, the foo variable was overwritten with some unexpected data (probably by a dangling pointer or whatever). So I added the additional debugging code : at init, the memory used by foo was indicated as a forbidden region to the MMU; each time foo was accessed on purpose, access to the region was allowed just before then forbidden just after; a MMU irq handler was added to dump the master and the address responsible of the violation. This was actually some kind of watchpoint, but directly self-handled by the code itself. Now, I would like to reuse the same trick, but on a x86 platform. The problem is that I am very far from understanding how is working the MMU on this platform, and how it is used by Linux, but I wonder if any library/tool/system call already exist to deal with this problem. Note that I am aware that various tools exist like Valgrind or GDB to manage memory problems, but as far as I know, none of these tools car be dynamically reconfigured by the debugged code. I am mainly interested for user space under Linux, but any info on kernel mode or under Windows is also welcome!

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  • Why are my connections not closed even if I explicitly dispose of the DataContext?

    - by Chris Simpson
    I encapsulate my linq to sql calls in a repository class which is instantiated in the constructor of my overloaded controller. The constructor of my repository class creates the data context so that for the life of the page load, only one data context is used. In my destructor of the repository class I explicitly call the dispose of the DataContext though I do not believe this is necessary. Using performance monitor, if I watch my User Connections count and repeatedly load a page, the number increases once per page load. Connections do not get closed or reused (for about 20 minutes). I tried putting Pooling=false in my config to see if this had any effect but it did not. In any case with pooling I wouldn't expect a new connection for every load, I would expect it to reuse connections. I've tried putting a break point in the destructor to make sure the dispose is being hit and sure enough it is. So what's happening? Some code to illustrate what I said above: The controller: public class MyController : Controller { protected MyRepository rep; public MyController () { rep = new MyRepository(); } } The repository: public class MyRepository { protected MyDataContext dc; public MyRepository() { dc = getDC(); } ~MyRepository() { if (dc != null) { //if (dc.Connection.State != System.Data.ConnectionState.Closed) //{ // dc.Connection.Close(); //} dc.Dispose(); } } // etc } Note: I add a number of hints and context information to the DC for auditing purposes. This is essentially why I want one connection per page load

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  • Java downcasting and is-A has-A relationship

    - by msharma
    HI, I have a down casting question, I am a bit rusty in this area. I have 2 clasess like this: class A{ int i; String j ; //Getters and setters} class B extends A{ String k; //getter and setter} I have a method like this, in a Utility helper class: public static A converts(C c){} Where C are objects that are retireved from the database and then converted. The problem is I want to call the above method by passing in a 'C' and getting back B. So I tried this: B bClasss = (B) Utility.converts(c); So even though the above method returns A I tried to downcast it to B, but I get a runtime ClassCastException. Is there really no way around this? DO I have to write a separate converts() method which returns a B class type? If I declare my class B like: class B { String k; A a;} // So instead of extending A it has-a A, getter and setters also then I can call my existing method like this: b.setA(Utility.converts(c) ); This way I can reuse the existing method, even though the extends relationship makes more sense. What should I do? Any help much appreciated. Thanks.

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  • Extjs 4.1 How to call controller action method from form

    - by Omar Faruq
    Extjs 4.1 How to call controller action method from form which is already use in a button action but i want this method reuse from a form field but do not how i can do? // here is my controller code init: function() { this.control({ 'itemsgrid': { removeitem: this.removeUser }, 'salewindow button[action=resetAll]': { click: this.resertform }, 'salewindow button[action=saveOrder]' : { click : this.onsaveOrder }, 'salewindow button[action=PDF]' : { click : this. pdfreport } }); }, resertform : function(button){ var store = Ext.data.StoreManager.get('Items'); store.destroy(); var vatstore = Ext.data.StoreManager.get('Vats'); vatstore.reload(); var rebatestore = Ext.data.StoreManager.get('Rebates'); rebatestore.reload(); Ext.getCmp('calculation-form').getForm().reset(); Ext.getCmp('itemform2').getForm().reset(); Ext.getCmp('itemsgrid').subtotalquantity(p=0); store.reload(); var co=store.getCount(); console.log(co); Ext.getCmp('customerID').setValue('0'); var a = Ext.getCmp('customerID').getValue(); Ext.getCmp('itemform2').customerinfo(a); } //and here is my from field listener { xtype : 'textfield', name : 'BranchId', fieldLabel : 'Branch Id', allowNegative : false, id : 'branchid', value : '1', onBlur: function(){ restoreItem();// i want call this method from here whis is stay in controller } }

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  • Examples using Active Directory/LDAP groups for permissions \ roles in Rails App.

    - by Nick Gorbikoff
    Hello. I was wondering how other people implemented this scenario. I have an internal rails app ( inventory management, label printing, shipping,etc). I'm rewriting security on the system, cause the old way got to cumbersome to maintain ( users table, passwords, roles) - I used restful_authentication and roles. It was implemented about 3 years ago. I already implemented AuthLogic with ruby-ldap-net to authenticate users ( actually that was surprisingly easy, compared to how I struggled with other frameworks/languages before). Next step is roles. I already have groups defined in Active Directory - so I don't want to run a separate roles system in my rails app, I just want to reuse Active Directory groups - since that part of the system is already maintained for other purposes ( shared drives, backups, pc access, etc) So I was wondering if others had experience implementing permissions/roles in a rails app based on groups in Active Directory or LDAP. Also the roles requirements are pretty complex. Here is an example: For instance I have users that belong to the supervisors group in AD and to inventory dept, so I was that user to be able to run "advanced" tasks in invetory - adjust qty, run reports, however other "supervisors" from other departmanets, shouldn't be able to do this, also Top Management - should be able to use those reports (regardless weather they belong to the invetory or not), but not Middle Management, unless they are in inventory group. Admins of the system (Domain Admins) should have unrestricted access to the system , except for HR & Finances part unless they are in HR ( like you don't want all system admins (except for one authorized one) to see personal info of other employees). I looked at acl9, cancan, aegis. I was wondering if there are any advantaged/cons to using one versus the other for this particular use of system access based on AD. Suggest other systems if you had good experience. Thank you!!!

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  • Pass ng-model and place-holder value into directive

    - by Zen
    I have a segment of code needs to be reuse a lot, there for I want to just create a directive for it. <div class="btn-group"> <div class="input-group"> <div class="has-feedback"> <input type="text" class="form-control" placeholder="BLAH BLAH" ng-model="model"> <span class="times form-control-feedback" ng-click="model=''" ng-show="model.length > 0"></span> </div> </div> </div> I want to use this code as template in directive. Create a directive used as follow: <div search-Field ng-model="model" placeholder="STRING"></div> to replace to old html, ng-model and placeholder will be as variables. angular.module('searchField', []) .directive('searchField', [function () { return { scope: { placeholder: '@', ngModel: '=' }, templateUrl: 'Partials/_SearchInputGroup.html' } }]); Is it the way of doing it?

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  • Connections hanging on read()

    - by viraptor
    Hi, Short version: I've got a strange issue with a server accepting TCP connections. Even though there are normally some processes waiting, at some volume of connections it hangs. Long version: The server is written in Perl and binds a $srv socket with the reuse flag and listen == 5. Afterwards, it forks into 10 processes with a loop of $clt=$srv->accept(); do_processing($clt); $clt->shutdown(2); The client written in C is also very simple - it sends some lines, then receives all lines available and does a shutdown(sockfd, 2); There's nothing async going on and at the end both send and receive queues are empty (as reported by netstat). Connections last only ~20ms. All clients behave the same way, are the same implementation, etc. Now let's say I'm accepting X connections from client 1 and another X from client 2. Processes still report that they're idle all the time. If I add another X connections from client 3, suddenly the server processes start hanging just after accepting. The first blocking thing they do after accept(); is while (<$clt>) ... - but they don't get any data (on the first try already). Suddenly all 10 processes are in this state and do not stop waiting. On strace, the server processes seem to hang on read(), which makes sense. There are loads of connections in TIME_WAIT state belonging to that server (~100 when the problem starts to manifest), but this might be a red herring. What could be happening here?

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