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• How to design a C / C++ library to be usable in many client languages?

  - by Brian Schimmel

  I'm planning to code a library that should be usable by a large number of people in on a wide spectrum of platforms. What do I have to consider to design it right? To make this questions more specific, there are four "subquestions" at the end. Choice of language Considering all the known requirements and details, I concluded that a library written in C or C++ was the way to go. I think the primary usage of my library will be in programs written in C, C++ and Java SE, but I can also think of reasons to use it from Java ME, PHP, .NET, Objective C, Python, Ruby, bash scrips, etc... Maybe I cannot target all of them, but if it's possible, I'll do it. Requirements It would be to much to describe the full purpose of my library here, but there are some aspects that might be important to this question: The library itself will start out small, but definitely will grow to enormous complexity, so it is not an option to maintain several versions in parallel. Most of the complexity will be hidden inside the library, though The library will construct an object graph that is used heavily inside. Some clients of the library will only be interested in specific attributes of specific objects, while other clients must traverse the object graph in some way Clients may change the objects, and the library must be notified thereof The library may change the objects, and the client must be notified thereof, if it already has a handle to that object The library must be multi-threaded, because it will maintain network connections to several other hosts While some requests to the library may be handled synchronously, many of them will take too long and must be processed in the background, and notify the client on success (or failure) Of course, answers are welcome no matter if they address my specific requirements, or if they answer the question in a general way that matters to a wider audience! My assumptions, so far So here are some of my assumptions and conclusions, which I gathered in the past months: Internally I can use whatever I want, e.g. C++ with operator overloading, multiple inheritance, template meta programming... as long as there is a portable compiler which handles it (think of gcc / g++) But my interface has to be a clean C interface that does not involve name mangling Also, I think my interface should only consist of functions, with basic/primitive data types (and maybe pointers) passed as parameters and return values If I use pointers, I think I should only use them to pass them back to the library, not to operate directly on the referenced memory For usage in a C++ application, I might also offer an object oriented interface (Which is also prone to name mangling, so the App must either use the same compiler, or include the library in source form) Is this also true for usage in C# ? For usage in Java SE / Java EE, the Java native interface (JNI) applies. I have some basic knowledge about it, but I should definitely double check it. Not all client languages handle multithreading well, so there should be a single thread talking to the client For usage on Java ME, there is no such thing as JNI, but I might go with Nested VM For usage in Bash scripts, there must be an executable with a command line interface For the other client languages, I have no idea For most client languages, it would be nice to have kind of an adapter interface written in that language. I think there are tools to automatically generate this for Java and some others For object oriented languages, it might be possible to create an object oriented adapter which hides the fact that the interface to the library is function based - but I don't know if its worth the effort Possible subquestions is this possible with manageable effort, or is it just too much portability? are there any good books / websites about this kind of design criteria? are any of my assumptions wrong? which open source libraries are worth studying to learn from their design / interface / souce? meta: This question is rather long, do you see any way to split it into several smaller ones? (If you reply to this, do it as a comment, not as an answer)

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• Seeking STL-aware c++filt

  - by Don Wakefield

  In my development environment, I'm compiling a code base using GNU C++ 3.4.6. Code is under development, and unfortunately crashes now and then. It's nice to be able to run the traceback through a demangler, and I use c++filt 3.4. The problem comes when functions have a number of STL parameters. Consider My_callback::operator()( Status&, std::set<std::string> const&, std::vector<My_parameter*> const&, My_attribute_set const&, std::vector<My_parameter_base*> const&, std::vector<My_parameter> const&, std::set<std::string> const& ) { // ... } When this function is in the traceback, the mangled output on my platform is: (_ZN30My_callbackclER11StatusRKSt3setISsSt4lessISsESaISsEERKSt6vectorIP13My_parameterSaISB_EERK17My_attribute_setRKS9_IP18My_parameter_baseSaISK_EERKS9_ISA_SaISA_EES8_+0x76a) [0x13ffdaa] c++filt kindly demangles it to (My_callback::operator()(Status&, std::set<std::basic_string<char, std::char_traits<char>, std::allocator<char> >, std::less<std::basic_string<char, std::char_traits<char>, std::allocator<char> > >, std::allocator<std::basic_string<char, std::char_traits<char>, std::allocator<char> > > > const&, std::vector<My_parameter*, std::allocator<My_parameter*> > const&, My_attribute_set const&, std::vector<My_parameter_base*, std::allocator<My_parameter_base*> > const&, std::vector<My_parameter, std::allocator<My_parameter> > const&, std::set<std::basic_string<char, std::char_traits<char>, std::allocator<char> >, std::less<std::basic_string<char, std::char_traits<char>, std::allocator<char> > >, std::allocator<std::basic_string<char, std::char_traits<char>, std::allocator<char> > > > const&)+0x76a) [0x13ffdaa] This is the same problem as compiler errors encountered when using templates. However, the STL is a fairly regular and recognizable package of templates. So what I'm hoping is that someone out there has created an enhanced version of c++filt which would dump something closer to the original function signature. Any hints?

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• Help creating a JavaScript mixin in Tapestry5?

  - by shane87

  I am creating a mixin which renders a javascript file when a textfield gains focus. I am new to the idea of mixins in Tapestry, and I am unsure of where to place my original javascript file which i wish to run when the textfield gains focus. The following is an example of my code: The Java mixin class: package asc.mixins; import org.apache.tapestry5.RenderSupport; import org.apache.tapestry5.annotations.AfterRender; import org.apache.tapestry5.annotations.Environmental; import org.apache.tapestry5.annotations.IncludeJavaScriptLibrary; import org.apache.tapestry5.annotations.InjectContainer; import org.apache.tapestry5.corelib.base.AbstractTextField; @IncludeJavaScriptLibrary("js_dasher_mixin.js") public class DasherMixin { @Environmental private RenderSupport renderSupport; @InjectContainer private AbstractTextField field; @AfterRender void addScript() { this.renderSupport.addScript("new JSDasher('%s');", this.field.getClientId()); } } The Javascript mixin file: JSDasher = Class.create({ initialize: function(textField) { this.textField = $(textField); this.textField.observe('focus', this.onFocus.bindAsEventListener(this)); }, onFocus: function(event) { //call my javascript init() function } } part of my javascript file I wish to run when the textfield gains focus: var posX, posY; // Sets up our global variables and dispatches an init request to the server. function init() { posX=0; posY=0; canvas = document.getElementById("canvas"); canvasWidth = canvas.offsetWidth; canvasHeight = canvas.offsetHeight; if (canvas.getContext) { ctx = canvas.getContext("2d"); } canvas.onclick = canvasClicked; canvas.onmousemove = mouseMoved; canvasOffsetX = findPosX(canvas); canvasOffsetY = findPosY(canvas); sessID = -1; sendInitRQ(canvasWidth, canvasHeight); } My javascript file is much larger than above, my question is where should I put my javascript code above? Should it all be contained in the mixin.js file? if so where exactly should it go? Thanks in advance for any help.

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• bottom uicomponent does not receive mouse events

  - by firemonkey

  HI, I am sure this is very basic, however I am not able to find the solution. I have a base ShapeContainer(UIComponent). I add a uicomponent which has mouse down listener to ShapeContainer. the listener works great. When I add a simple sprite(draw square) on the ShapeContainer, The listener does not work any more. In the code, if I comment below lines, The event listener works fine. var square:Sprite = new Sprite(); square.graphics.lineStyle(4,0x00FF00); square.graphics.drawRect(0,0,20,20); square.mouseEnabled=false; shapeContainer.addChildAt(square,1); I have tried few things like, mouseenabled=false on top sprite. also tried to add addChildAt but non of them did any help. How can I draw a shape and also have the event listener work. enter code here protected function application1_creationCompleteHandler(event:FlexEvent):void { var shapeContainer:UIComponent = new UIComponent(); shapeContainer.x=100; shapeContainer.y=100; shapeContainer.width=200; shapeContainer.height=200; rawChildren.addChild(shapeContainer); var EventListenerShape:UIComponent = new UIComponent(); EventListenerShape.x=100; EventListenerShape.y=100; EventListenerShape.width=200;a EventListenerShape.height=200; EventListenerShape.graphics.clear(); EventListenerShape.graphics.beginFill(0xf1f1f1, 0.1); EventListenerShape.graphics.drawRoundRect(0, 0, 200, 200, 10, 10); EventListenerShape.alpha = 0; EventListenerShape.graphics.endFill(); EventListenerShape.addEventListener(MouseEvent.MOUSE_DOWN, mouseDownfunc); shapeContainer.addChild(EventListenerShape); var square:Sprite = new Sprite(); square.graphics.lineStyle(4,0x00FF00); square.graphics.drawRect(0,0,20,20); square.mouseEnabled=false; shapeContainer.addChildAt(square,1); } private function mouseDownfunc(e:MouseEvent){ trace("mouse Down **"); }    ]]> </mx:Script> <mx:Canvas id="uic" width="100%" height="100%" backgroundColor="0xFFFFFF"> </mx:Canvas>

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• Non Document Centric SharePoint Workflow

  - by Dan Revell

  SharePoint workflows are document centric in that the base thing the workflow runs on has to be a thing; be it a document or just a list item. The workflow itself is task based, so stuff a user has to do. Now I can put any sort of code in these tasks that I want to and even put complex InfoPath forms in for the user to perform the task. This has been fine on all my previous workflows. But what if I want the tasks to be actual official forms themselves. The item that the workflow runs on is just some abstract concept like an event. An example could be an accident has happened. There isn't an accident form, but a whole set of forms that need to be completed by different people. Task forms aren't really a nice way to go, because it locks all the forms into the task list. You can only access the forms by not deleting the tasks when complete and going to the workflow summery and following the task links to the InfoPath forms or going straight to the tasks list and doing a filter on particular "accidents". These are official documents so ideally there would be a library for each type of document and the workflow would orchestrate the completion of the right forms. It would mean each task would have to create a new blank form and then link the user to that form. The user would go complete the form but then have to go back to the task form and click yes I've completed it until the workflow could progress. Well this is short of the workflow monitoring the forms library form for some completion trigger. But then it all gets messy with the user experience from clicking the link in the task email, to open the Infopath task form, to clicking the link in the subsequent Infopath library form and then return through these forms on completion. It just gets messy trying to retrofit this non document centric sort of workflow into SharePoint. I would really appreciate any input on what might be the best way to do this. Store the forms as task forms Store the forms as library forms and create/link from the task forms Store the forms as different infopath views, and use a forms library. The workflow would trigger variables that progress the view the infopath form shows. Using the same form template for both task forms and a forms library and when a task form is complete, copy the xml into the forms library to have a official record outside of the workflow. Thanks

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• Question about design (inheritance, polymorphism)

  - by Dan

  Hi, I have a question about a problem I'm struggling with. Hope you can bear with me. Imagine I have an Object class representing the base class of a hierarchy of physical objects. Later I inherit from it to create an Object1D, Object2D and Object3D classes. Each of these derived classes will have some specific methods and attributes. For example, the 3d object might have functionality to download a 3d model to be used by a renderer. So I'd have something like this: class Object {}; class Object1D : public Object { Point mPos; }; class Object2D : public Object { ... }; class Object3D : public Object { Model mModel; }; Now I'd have a separate class called Renderer, which simply takes an Object as argument and well, renders it :-) In a similar way, I'd like to support different kinds of renderers. For instance, I could have a default one that every object could rely on, and then provide other specific renderers for some kind of objects: class Renderer {}; // Default one class Renderer3D : public Renderer {}; And here comes my problem. A renderer class needs to get an Object as an argument, for example in the constructor in order to retrieve whatever data it needs to render the object. So far so good. But a Renderer3D would need to get an Object3D argument, in order to get not only the basic attributes but also the specific attributes of a 3d object. Constructors would look like this: CRenderer(Object& object); CRenderer3D(Object3D& object); Now how do I specify this in a generic way? Or better yet, is there a better way to design this? I know I could rely on RTTI or similar but I'd like to avoid this if possible as I feel there is probably a better way to deal with this. Thanks in advance!

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• Best method for converting several sets of numbers with several different ratios

  - by C Patton

  I'm working on an open-source harm reduction application for opioid addicts. One of the features in this application is the conversion (in mg/mcg) between common opioids, so people don't overdose by accident. If you're morally against opioid addiction and wouldn't respond because of your morals, please consider that this application is for HARM REDUCTION.. So people don't end up dead. I have this data.. 3mg morphine IV = 10mcg fentanyl IV 2mg morphine oral = 1mg oxycodone oral 3mg oral morphine = 1mg oxymorphone oral 7.0mg morphine oral = 1mg hydromorphone oral 1mg morphine iv = .10mg oxymorphone iv 1mg morphine oral = 1mg hydrocodone oral 1mg morphine oral = 6.67mg codeine oral 1mg morphine oral = .10mg methadone oral And I have a textbox that is the source dosage in mg (a double) that the user can enter in. Underneath this, I have radio boxes for the source substance (ie: morphine) and the destination substance (ie oxycodone) for conversion.. I've been trying to think of the most efficient way to do this, but nearly every seems sloppy. If I were to do something like public static double MorphinetoOxycodone(string morphineValue) { double morphine = Double.Parse(morphineValue); return (morphine / 2 ); } I would also have to make a function for OxycodonetoMorphine, OxycodonetoCodeine, etc.. and then would end up with dozens functions.. There must be an easier way than this that I'm missing. If you'll notice, all of my conversions use morphine as the base value.. what might be the easiest way to use the morphine value to convert one opioid to another? For example, if 1mg morphine oral is equal to 1mg hydrocodone and 1mg morphine oral is equal to .10mg methadone, wouldn't I just multiply 1*.10 to get the hydrocodone-methadone value? Implementing this idea is what I'm having the most trouble with. Any help would be GREATLY appreciated.. and if you'd like, I would add your name/nickname to the credits in this program. It's possible that many, many people around the world will use this (I'm translating it into several languages as well) and to know that your work could've helped an addict from dying.. I think that's a great thing :) -cory

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• Modern alternatives to Java

  - by Ralph

  I have been a Java developer for 14 years and have written an enterprise-level (~500 kloc) Swing application that uses most of the standard library APIs. Recently, I have become disappointed with the progress that the language has made to "modernize" itself, and am looking for an alternative for ongoing development. I have considered moving to the .NET platform, but I have issues with using something the only runs well in Windows (I know about Mono, but that is still far behind Microsoft). I also plan on buying a new Macbook Pro as soon as Apple releases their new rumored Arrandale-based machines and want to develop in an environment that will feel "at home" in Unix/Linux. I have considered using Python or Ruby, but the standard Java library is arguably the largest of any modern language. In JVM-based languages, I looked at Groovy, but am disappointed with its performance. Rumor has it that with the soon-to-be released JDK7, with its InvokeDynamic instruction, this will improve, but I don't know how much. Groovy is also not truly a functional language, although it provides closures and some of the "functional" features on collections. It does not embrace immutability. I have narrowed my search down to two JVM-based alternatives: Scala and Clojure. Each has its strengths and weaknesses. I am looking for opinions. I am not an expert at either of these languages; I have read 2 1/2 books on Scala and am currently reading Stu Halloway's book on Clojure. Scala is strongly statically typed. I know the dynamic language folks claim that static typing is a crutch for not doing unit testing, but it does provide a mechanism for compile-time location of a whole class of errors. Scala is more concise than Java, but not as much as Clojure. Scala's inter-operation with Java seems to be better than Clojure's, in that most Java operations are easier to do in Scala than in Clojure. For example, I can find no way in Clojure to create a non-static initialization block in a class derived from a Java superclass. For example, I like the Apache commons CLI library for command line argument parsing. In Java and Scala, I can create a new Options object and add Option items to it in an initialization block as follows (Java code): final Options options = new Options() { { addOption(new Option("?", "help", false, "Show this usage information"); // other options } }; I can't figure out how to the same thing in Clojure (except by using (doit...)), although that may reflect my lack of knowledge of the language. Clojure's collections are optimized for immutability. They rarely require copy-on-write semantics. I don't know if Scala's immutable collections are implemented using similar algorithms, but Rich Hickey (Clojure's inventor) goes out of his way to explain how that language's data structures are efficient. Clojure was designed from the beginning for concurrency (as was Scala) and with modern multi-core processors, concurrency takes on more importance, but I occasionally need to write simple non-concurrent utilities, and Scala code probably runs a little faster for these applications since it discourages, but does not prohibit, "simple" mutability. One could argue that one-off utilities do not have to be super-fast, but sometimes they do tasks that take hours or days to complete. I know that there is no right answer to this "question", but I thought I would open it up for discussion. Are there other JVM-based languages that can be used for enterprise level development?

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• C# Select clause returns system exception instead of relevant object

  - by Kashif

  I am trying to use the select clause to pick out an object which matches a specified name field from a database query as follows: objectQuery = from obj in objectList where obj.Equals(objectName) select obj; In the results view of my query, I get: base {System.SystemException} = {"Boolean Equals(System.Object)"} Where I should be expecting something like a Car, Make, or Model Would someone please explain what I am doing wrong here? The method in question can be seen here: // this function searches the database's table for a single object that matches the 'Name' property with 'objectName' public static T Read<T>(string objectName) where T : IEquatable<T> { using (ISession session = NHibernateHelper.OpenSession()) { IQueryable<T> objectList = session.Query<T>(); // pull (query) all the objects from the table in the database int count = objectList.Count(); // return the number of objects in the table // alternative: int count = makeList.Count<T>(); IQueryable<T> objectQuery = null; // create a reference for our queryable list of objects T foundObject = default(T); // create an object reference for our found object if (count > 0) { // give me all objects that have a name that matches 'objectName' and store them in 'objectQuery' objectQuery = from obj in objectList where obj.Equals(objectName) select obj; // make sure that 'objectQuery' has only one object in it try { foundObject = (T)objectQuery.Single(); } catch { return default(T); } // output some information to the console (output screen) Console.WriteLine("Read Make: " + foundObject.ToString()); } // pass the reference of the found object on to whoever asked for it return foundObject; } } Note that I am using the interface "IQuatable<T>" in my method descriptor. An example of the classes I am trying to pull from the database is: public class Make: IEquatable<Make> { public virtual int Id { get; set; } public virtual string Name { get; set; } public virtual IList<Model> Models { get; set; } public Make() { // this public no-argument constructor is required for NHibernate } public Make(string makeName) { this.Name = makeName; } public override string ToString() { return Name; } // Implementation of IEquatable<T> interface public virtual bool Equals(Make make) { if (this.Id == make.Id) { return true; } else { return false; } } // Implementation of IEquatable<T> interface public virtual bool Equals(String name) { if (this.Name.Equals(name)) { return true; } else { return false; } } } And the interface is described simply as: public interface IEquatable<T> { bool Equals(T obj); }

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• Rails 3 - development errors in production mode

  - by skrafi

  Im using Rails, Passenger (both are 3.0.5) and Nginx on my production server. As I heard, Rails should show public/404.html or public/500.html instead of development errors like ActiveRecord::RecordNotFound or Unknown action but that doesn't happen. I've tried to delete config.ru file and set rack_env or rails_env in nginx.conf but nothing helped. Here is my nginx.conf: worker_processes 1; events { worker_connections 1024; } http { passenger_root /home/makk/.rvm/gems/ruby-1.9.2-p0/gems/passenger-3.0.5; passenger_ruby /home/makk/.rvm/bin/passenger_ruby; #passenger_ruby /home/makk/.rvm/wrappers/ruby-1.9.2-p0/ruby; include mime.types; default_type application/octet-stream; sendfile on; keepalive_timeout 65; server { listen 80; server_name localhost; location / { root /home/makk/projects/1server/deploy/current/public; index index.html index.htm; passenger_enabled on; rack_env production; recursive_error_pages on; if (-f /home/makk/projects/1server/maintenance.html) { return 503; } error_page 404 /404.html; error_page 500 502 504 /500.html; error_page 503 @503; } location @503 { error_page 405 = /maintenance.html; # Serve static assets if found. if (-f $request_filename) { break; } rewrite ^(.*)$ /maintenance.html break; } location ~ ^(\/phpmyadmin\/)(.*)$ { fastcgi_pass 127.0.0.1:9000; fastcgi_index index.php; fastcgi_split_path_info ^(\/phpmyadmin\/)(.*)$; fastcgi_param SCRIPT_FILENAME /usr/share/phpmyadmin/$fastcgi_path_info; include fastcgi_params; } } } It seems that this question duplicates this one but there are no working suggestions. UPD: I have both development and production apps on same PC. In production Rails ignores config.consider_all_requests_local = false (in /config/environments/production.rb) due to local_request? method. So one of possible solutions is listed below (taken from here): # config/initializers/local_request_override.rb module CustomRescue def local_request? return false if Rails.env.production? || Rails.env.staging? super end end ActionController::Base.class_eval do include CustomRescue end Or for Rails 3: class ActionDispatch::Request def local? false end end

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• php, mySQL & AJAX: Unable to use sessions across the scripts in the same domain

  - by Devner

  Hi all, I have the following pages: page1.php, page2.php and page3.php. Code in each of them is as below CODE: page1.php <script type="text/javascript"> $(function(){ $('#imgID').upload({ submit_to_url: "page2.php", file_name: 'myfile1', description : "Image", limit : 1, file_types : "*.jpg", }) }); </script> <body> <form action="page3.php" method="post" enctype="multipart/form-data" name="frm1" id="frm1"> //Some other text fields <input type="submit" name="submit" id="submit" value="Submit" /> </form> </body> page2.php <?php session_start(); $a = $_SESSION['a']; $b = $_SESSION['b']; $c = $_SESSION['c']; $res = mysql_query("SELECT col FROM table WHERE col1 = $a AND col2 = $b AND col3 = $c LIMIT 1"); $num_rows = mysql_num_rows($res); echo $num_rows; //echos 0 when in fact it should have been 1 because the data in the Session exists. //Ok let's proceed further //... Do some stuff... //Store some more values and create new session variables (and assume that page1.php is going to be able to use it) $_SESSION['d'] = 'd'; $_SESSION['e'] = 'e'; $_SESSION['f'] = 'f'; if (move_uploaded_file($_FILES['file']['tmp_name'], $file)) { echo "success"; } else { echo "error ".$_FILES['file']['error']; } ?> page3.php <?php session_start(); if( isset($_POST['submit']) ) { //These sessions are non-existent although the AJAX request //to page2.php may have created them when called via AJAX from within page1.php echo $_SESSION['d'].$_SESSION['e'].$_SESSION['f']; ?> } ?> As the code says it I am posting some info via AJAX call from page1.php to page2.php. page2.php is supposed to be able to use the session values from page1.php i.e. $_SESSION['a'], $_SESSION['b'] and $_SESSION['c'] but it does not. Why? How can I fix this? page2.php is creating some more sessions after some processing is done and a response is sent back to page1.php. The submit button of the form on page1.php is hit and the page gets POST'ed to page3.php. But when the SESSION info that gets created in page2.php is echoed, it's blank signifying that SESSIONS from page2.php are not used. How can I fix this? I looked over a lot of information and have spent about 50 hours trying to do different things with my scripts before arriving at the above conclusions. My app. is custom made using function (not OOPS) and does not use any PHP frameworks & I am not even about to use any as my knowledge of OOP concepts is limited any many frameworks are object oriented. I came across race conditions, but the solutions provided don't help too much. One more solution of using DB to hold sessions and seek and retrieve from DB is the last thing on my mind and I really want to avoid creating table, coding and maintaining code for a task as simple as just keeping sessions across pages in the same domain. So my request is: Is there a way that I can solve the above problem(s) via simple coding in present conditions? Any help is appreciated. Thank you.

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• What is the best way to create related types at runtime?

  - by SniperSmiley

  How do I determine the type of a class that is related to another class at runtime? I have figured out a solution, the only problem is that I ended up having to use a define that has to be used in all of the derived classes. Is there a simpler way to do this that doesn't need the define or a copy paste? Things to note: both the class and the related class will always have their respective base class, the different classes can share a related class, and as in the example I would like the control class to own the view. #include <iostream> #include <string> class model; class view { public: view( model *m ) {} virtual std::string display() { return "view"; } }; #define RELATED_CLASS(RELATED)\ typedef RELATED relatedType;\ virtual relatedType*createRelated(){\ return new relatedType(this);} class model { public: RELATED_CLASS(view) model() {} }; class otherView : public view { public: otherView( model *m ) : view(m) {} std::string display() { return "otherView"; } }; class otherModel : public model { public: RELATED_CLASS(otherView) otherModel() {} }; class control { public: control( model *m ) : m_(m), v_( m->createRelated() ) {} ~control() { delete v_; } std::string display() { return v_->display(); } model *m_; view *v_; }; int main( void ) { model m; otherModel om; model *pm = &om; control c1( &m ); control c2( &om ); control c3( pm ); std::cout << c1.display() << std::endl; std::cout << c2.display() << std::endl; std::cout << c3.display() << std::endl; }

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• How to modify my Response.Document XSD for getting author name form Sharepoint

  - by Rohan Patil

  Hi, This is my XSD currently <?xml version="1.0" encoding="Windows-1252"?> <xsd:schema xmlns:tns="urn:Microsoft.Search.Response.Document" attributeFormDefault="unqualified" elementFormDefault="qualified" targetNamespace="urn:Microsoft.Search.Response.Document" xmlns:xsd="http://www.w3.org/2001/XMLSchema"> <xsd:import namespace="urn:Microsoft.Search.Response.Document.Document" schemaLocation="Microsoft.Search.Response.Document.Document.xsd" /> <xsd:annotation> <xsd:documentation> </xsd:documentation> <xsd:documentation> Defines a Query Respnose from a Windows SharePoint Services 3.0 Query Service. </xsd:documentation> </xsd:annotation> <!-- - - - - - - - - - - - - - - - - - - - - - - - - - --> <!-- Root Element: Document --> <!-- - - - - - - - - - - - - - - - - - - - - - - - - - --> <xsd:element name="Document"> <xsd:complexType> <xsd:sequence> <xsd:element name="Title" type="xsd:string" minOccurs="0" /> <xsd:element name="Action"> <xsd:complexType> <xsd:sequence> <xsd:element name="LinkUrl"> <xsd:complexType> <xsd:simpleContent> <xsd:extension base="xsd:string"> <xsd:attribute name="size" type="xsd:unsignedByte" use="optional" /> <xsd:attribute name="fileExt" type="xsd:string" use="required" /> </xsd:extension> </xsd:simpleContent> </xsd:complexType> </xsd:element> </xsd:sequence> </xsd:complexType> </xsd:element> <xsd:element name="Description" type="xsd:string" minOccurs="0" /> <xsd:element name="Date" type="xsd:dateTime" minOccurs="0" /> <xsd:element xmlns:q1="urn:Microsoft.Search.Response.Document.Document" ref="q1:Properties" minOccurs="0" /> </xsd:sequence> <xsd:attribute name="relevance" type="xsd:unsignedByte" use="optional" /> </xsd:complexType> </xsd:element> </xsd:schema> I want to able to get the author name.. Please help..

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• Android: Creating custom class of resources

  - by Sebastian

  Hi, R class on android has it's limitations. You can't use the resources dynamically for loading audio, pictures or whatever. If you wan't for example, load a set of audio files for a choosen object you can't do something like: R.raw."string-upon-choosen-object" I'm new to android and at least I didn't find how you could do that, depending on what objects are choosen or something more dynamic than that. So, I thought about making it dynamic with a little of memory overhead. But, I'm in doubt if it's worth it or just working different with external resources. The idea is this: Modify the ant build xml to execute my own task. This task, is a java program that parses the R.java file building a set of HashMaps with it's pair (key, value). I have done this manually and It's working good. So I need some experts voice about it. This is how I will manage the whole thing: Generate a base Application class, e.g. MainApplicationResources that builds up all the require methods and attributes. Then, you can access those methods invoking getApplication() and then the desired method. Something like this: package [packageName] import android.app.Application; import java.util.HashMap; public class MainActivityResources extends Application { private HashMap<String,Integer> [resNameObj1]; private HashMap<String,Integer> [resNameObj2]; ... private HashMap<String,Integer> [resNameObjN]; public MainActivityResources() { super(); [resNameObj1] = new HashMap<String,Integer>(); [resNameObj1].put("[resNameObj1_Key1]", new Integer([resNameObj1_Value1])); [resNameObj1].put("[resNameObj1_Key2]", new Integer([resNameObj1_Value2])); [resNameObj2] = new HashMap<String,Integer>(); [resNameObj2].put("[resNameObj2_Key1]", new Integer([resNameObj2_Value1])); [resNameObj2].put("[resNameObj2_Key2]", new Integer([resNameObj2_Value2])); ... [resNameObjN] = new HashMap<String,Integer>(); [resNameObjN].put("[resNameObjN_Key1]", new Integer([resNameObjN_Value1])); [resNameObjN].put("[resNameObjN_Key2]", new Integer([resNameObjN_Value2])); } public int get[ResNameObj1](String resourceName) { return [resNameObj1].get(resourceName).intValue(); } public int get[ResNameObj2](String resourceName) { return [resNameObj2].get(resourceName).intValue(); } ... public int get[ResNameObjN](String resourceName) { return [resNameObjN].get(resourceName).intValue(); } } The question is: Will I add too much memory use of the device? Is it worth it? Regards,

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• User created Validator wont call Client side validation Javascript on 'complex' user control.

  Hi All, I have created a user control (from System.Web.UI.UserControl), and created my own validator for the user control (from System.Web.UI.WebControls.BaseValidator). Everything works ok until I try to get the user control to do client side validation. While trying to debug this issue I have set 'Control to Validate' to a text box instead of the custom user control, and the client side script works fine! It appears to me that it has an a issue with my composite user control I have created. Has anyone encountered this issue before? Has anyone else seen client side validation fail on custom user controls? Some extra info : The composite control is a drop down list and 'loader image', as it is a ajax enabled drop down list (using ICallbackEventHandler). I know that the client side javascript is being written to the page, and have placed an alert('random message') as the first line in the validator function that only appears if it is validating a text box (i.e. not when it is validating my custom control) Language : C# (ASP.NET 2.0) and jQuery 1.2.6 in aspx file : <rms:UserDDL ID="ddlUserTypes" runat="server" PreLoad="true" /> <rms:DDLValidator ID="userTypesVal" ControlToValidate="ddlUserTypes" ErrorMessage="You have not selected a UserType" runat="server" Text="You have not selected a UserType" Display="Dynamic" EnableClientScript="true" /> in validator code behind protected string ScriptBlock { get { string nl = System.Environment.NewLine; return "<script type=\"text/javascript\">" + nl + " function " + ScriptBlockFunctionName + "(ctrl)" + nl + " {" + nl + " alert('Random message'); " + nl + " var selVal = $('#' + ctrl.controltovalidate).val(); " + nl + " alert(selVal);" + nl + " if (selVal === '-1') return false; " + nl + " return false; " + nl + " }" + nl + "</script>"; } } protected override void OnPreRender(EventArgs e) { if (this.DetermineRenderUplevel() && this.EnableClientScript) { Page.ClientScript.RegisterExpandoAttribute(this.ClientID, "evaluationfunction", this.ScriptBlockFunctionName); Page.ClientScript.RegisterClientScriptBlock(GetType(), this.ScriptBlockKey, this.ScriptBlock); } base.OnPreRender(e); } I know my ControlPropertiesValid() and EvaluateIsValid() work ok. I appreciate any help on this issue. Noel.

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• Internet Explorer Automation: how to suppress Open/Save dialog?

  - by Vladimir Dyuzhev

  When controlling IE instance via MSHTML, how to suppress Open/Save dialogs for non-HTML content? I need to get data from another system and import it into our one. Due to budget constraints no development (e.g. WS) can be done on the other side for some time, so my only option for now is to do web scrapping. The remote site is ASP.NET-based, so simple HTML requests won't work -- too much JS. I wrote a simple C# application that uses MSHTML and SHDocView to control an IE instance. So far so good: I can perform login, navigate to desired page, populate required fields and do submit. Then I face a couple of problems: First is that report is opening in another window. I suspect I can attach to that window too by enumerating IE windows in the system. Second, more troublesome, is that report itself is CSV file, and triggers Open/Save dialog. I'd like to avoid it and make IE save the file into given location OR I'm fine with programmatically clicking dialog buttons too (how?) I'm actually totally non-Windows guy (unix/J2EE), and hope someone with better knowledge would give me a hint how to do those tasks. Thanks! UPDATE I've found a promising document on MSDN: http://msdn.microsoft.com/en-ca/library/aa770041.aspx Control the kinds of content that are downloaded and what the WebBrowser Control does with them once they are downloaded. For example, you can prevent videos from playing, script from running, or new windows from opening when users click on links, or prevent Microsoft ActiveX controls from downloading or executing. Slowly reading through... UPDATE 2: MADE IT WORK, SORT OF... Finally I made it work, but in an ugly way. Essentially, I register a handler "before navigate", then, in the handler, if the URL is matching my target file, I cancel the navigation, but remember the URL, and use WebClient class to access and download that temporal URL directly. I cannot copy the whole code here, it contains a lot of garbage, but here are the essential parts: Installing handler: _IE2.FileDownload += new DWebBrowserEvents2_FileDownloadEventHandler(IE2_FileDownload); _IE.BeforeNavigate2 += new DWebBrowserEvents2_BeforeNavigate2EventHandler(IE_OnBeforeNavigate2); Recording URL and then cancelling download (thus preventing Save dialog to appear): public string downloadUrl; void IE_OnBeforeNavigate2(Object ob1, ref Object URL, ref Object Flags, ref Object Name, ref Object da, ref Object Head, ref bool Cancel) { Console.WriteLine("Before Navigate2 "+URL); if (URL.ToString().EndsWith(".csv")) { Console.WriteLine("CSV file"); downloadUrl = URL.ToString(); } Cancel = false; } void IE2_FileDownload(bool activeDocument, ref bool cancel) { Console.WriteLine("FileDownload, downloading "+downloadUrl+" instead"); cancel = true; } void IE_OnNewWindow2(ref Object o, ref bool cancel) { Console.WriteLine("OnNewWindow2"); _IE2 = new SHDocVw.InternetExplorer(); _IE2.BeforeNavigate2 += new DWebBrowserEvents2_BeforeNavigate2EventHandler(IE_OnBeforeNavigate2); _IE2.Visible = true; o = _IE2; _IE2.FileDownload += new DWebBrowserEvents2_FileDownloadEventHandler(IE2_FileDownload); _IE2.Silent = true; cancel = false; return; } And in the calling code using the found URL for direct download: ... driver.ClickButton(".*_btnRunReport"); driver.WaitForComplete(); Thread.Sleep(10000); WebClient Client = new WebClient(); Client.DownloadFile(driver.downloadUrl, "C:\\affinity.dump"); (driver is a simple wrapper over IE instance = _IE) Hope that helps someone.

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• How do I classify using SVM Classifier?

  - by Gomathi

  I'm doing a project in liver tumor classification. Actually I initially used Region Growing method for liver segmentation and from that I segmented tumor using FCM. I,then, obtained the texture features using Gray Level Co-occurence Matrix. My output for that was stats = autoc: [1.857855266614132e+000 1.857955341199538e+000] contr: [5.103143332457753e-002 5.030548650257343e-002] corrm: [9.512661919561399e-001 9.519459060378332e-001] corrp: [9.512661919561385e-001 9.519459060378338e-001] cprom: [7.885631654779597e+001 7.905268525471267e+001] Now how should I give this as an input to the SVM program. function [itr] = multisvm( T,C,tst ) %MULTISVM(2.0) classifies the class of given training vector according to the % given group and gives us result that which class it belongs. % We have also to input the testing matrix %Inputs: T=Training Matrix, C=Group, tst=Testing matrix %Outputs: itr=Resultant class(Group,USE ROW VECTOR MATRIX) to which tst set belongs %----------------------------------------------------------------------% % IMPORTANT: DON'T USE THIS PROGRAM FOR CLASS LESS THAN 3, % % OTHERWISE USE svmtrain,svmclassify DIRECTLY or % % add an else condition also for that case in this program. % % Modify required data to use Kernel Functions and Plot also% %----------------------------------------------------------------------% % Date:11-08-2011(DD-MM-YYYY) % % This function for multiclass Support Vector Machine is written by % ANAND MISHRA (Machine Vision Lab. CEERI, Pilani, India) % and this is free to use. email: [email protected] % Updated version 2.0 Date:14-10-2011(DD-MM-YYYY) u=unique(C); N=length(u); c4=[]; c3=[]; j=1; k=1; if(N>2) itr=1; classes=0; cond=max(C)-min(C); while((classes~=1)&&(itr<=length(u))&& size(C,2)>1 && cond>0) %This while loop is the multiclass SVM Trick c1=(C==u(itr)); newClass=c1; svmStruct = svmtrain(T,newClass); classes = svmclassify(svmStruct,tst); % This is the loop for Reduction of Training Set for i=1:size(newClass,2) if newClass(1,i)==0; c3(k,:)=T(i,:); k=k+1; end end T=c3; c3=[]; k=1; % This is the loop for reduction of group for i=1:size(newClass,2) if newClass(1,i)==0; c4(1,j)=C(1,i); j=j+1; end end C=c4; c4=[]; j=1; cond=max(C)-min(C); % Condition for avoiding group %to contain similar type of values %and the reduce them to process % This condition can select the particular value of iteration % base on classes if classes~=1 itr=itr+1; end end end end Kindly guide me. Images:

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• How do I create a Spring 3 + Tiles 2 webapp using REST-ful URLs?

  - by Ichiro Furusato

  I'm having a heck of a time resolving URLs with Spring 3.0 MVC. I'm just building a HelloWorld to try out how to build a RESTful webapp in Spring, nothing theoretically complicated. All of the examples I've been able to find are based on configurations that pay attention to file extensions ("*.htm" or "*.do"), include an artificial directory name prefix ("/foo") or even prefix paths with a dot (ugly), all approaches that use some artificial regex pattern as a signal to the resolver. For a REST approach I want to avoid all that muck and use only the natural URL patterns of my application. I would assume (perhaps incorrectly) that in web.xml I'd set a url-pattern of "/*" and pass everything to the DispatcherServlet for resolution, then just rely on URL patterns in my controller. I can't reliably get my resolver(s) to catch the URL patterns, and in all my trials this results in a resource not found error, a stack overflow (loop), or some kind of opaque Spring 3 ServletException stack trace — one of my ongoing frustrations with Spring generally is that the error messages are not often very helpful. I want to work with a Tiles 2 resolver. I've located my *.jsp files in WEB-INF/views/ and have a single line index.jsp file at the application root redirecting to the index file set by my layout.xml (the Tiles 2 Configurer). I do all the normal Spring 3 high-level configuration: <mvc:annotation-driven /> <mvc:view-controller path="/" view-name="index"/> <context:component-scan base-package="com.acme.web.controller" /> ...followed by all sorts of combinations and configurations of UrlBasedViewResolver, InternalResourceViewResolver, UrlFilenameViewController, etc. with all manner of variantions in my Tiles 2 configuration file. Then in my controller I've trying to pick up my URL patterns. Problem is, I can't reliably even get the resolver(s) to catch the patterns to send to my controller. This has now stretched to multiple days with no real progress on something I thought would be very simple to implement. I'm perhaps trying to do too much at once, though I would think this should be a simple (almost a default) configuration. I'm just trying to create a simple HelloWorld-type application, I wouldn't expect this is rocket science. Rather than me post my own configurations (which have ranged all over the map), does anyone know of an online example that: shows a simple Spring 3 MVC + Tiles 2 web application that uses REST-ful URLs (i.e., avoiding forced URL patterns such as file extensions, added directory names or dots) and relies solely on Spring 3 code/annotations (i.e., nothing outside of Spring MVC itself) to accomplish this? Is there an easy way to do this? Thanks very much for any help.

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• XML Schema for a .NET type that inherits and implements

  - by John Ruiz

  Hi, Please consider the following three .NET types: I have an interface, an abstract class, and a concrete class. My question is how to write the XML Schema to include the properties from the interface and from the abstract class. public interface IStartable { bool RequiresKey { get; set; } void Start(object key); } public abstract class Vehicle { uint WheelCount { get; set; } } public class Car : Vehicle, IStartable { public bool RequiresKey { get; set; } public string Make { get; set; } publilc string Model { get; set; } public Car() {} public void Start(object key) { // start car with key } } I don't know how to complete this schema: <xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema" targetNamespace="cars" xmlns="cars" xmlns:c="cars"> <!-- How do I get car to have vehicle's wheelcount AND IStartable's RequiresKey? --> <xs:element name="Car" type="c:Car" /> <xs:complexType name="Car"> <xs:complexContent> <xs:extension base="c:Vehicle"> <xs:group ref=c:CarGroup" /> </xs:extension> </xs:complexContent> </xs:complexType> <xs:group name="CarGroup"> <xs:sequence> <xs:element name="Make" type="xs:token" /> <xs:element name="Model" type="xs:token" /> </xs:sequence> </xs:group> <xs:complexType name="Vehicle"> <xs:sequence> <xs:element name="WheelCount" type="xs:unsignedInt" /> </xs:sequence> </xs:complexType> <xs:complexType name="IStartable"> <xs:sequence> <xs:element name="RequiresKey" type="xs:boolean" /> </xs:sequence> </xs:complexType> </xs:schema>

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• How do I display a jquery dialog box before the entire page is loaded?

  - by obarshay

  On my site a number of operations can take a long time to complete. When I know a page will take a while to load, I would like to display a progress indicator while the page is loading. Ideally I would like to say something along the lines of: $("#dialog").show("progress.php"); and have that overlay on top of the page that is being loaded (disappearing after the operation is completed). Coding the progress bar and displaying progress is not an issue, the issue is getting a progress indicator to pop up WHILE the page is being loaded. I have been trying to use JQuery's dialogs for this but they only appear after the page is already loaded. This has to be a common problem but I am not familiar enough with JavaScript to know the best way to do this. Here's simple example to illustrate the problem. The code below fails to display the dialog box before the 20 second pause is up. I have tried in Chrome and Firefox. In fact I don't even see the "Please Wait..." text. Here's the code I am using: <html> <head> <link type="text/css" href="http://jqueryui.com/latest/themes/base/ui.all.css" rel="stylesheet" /> <script type="text/javascript" src="http://jqueryui.com/latest/jquery-1.3.2.js"></script> <script type="text/javascript" src="http://jqueryui.com/latest/ui/ui.core.js"></script> <script type="text/javascript" src="http://jqueryui.com/latest/ui/ui.dialog.js"></script> </head> <body> <div id="please-wait">My Dialog</div> <script type="text/javascript"> $("#please-wait").dialog(); </script> <?php flush(); echo "Waiting..."; sleep(20); ?> </body> </html>

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• Rails & Twilio: Receiving nil when storing texts received from Twilio

  - by Jon Smooth

  I have set up the request URL in my Twilio account to have it POST to: myurl.com/receivetext. It appears to be successfully posting because when I check the database using the Heroku console I see the following: Post id: 5, body: nil, from: nil, created_at: "2012-06-14 17:28:01", updated_at: "2012-06-14 17:28:01" Why is it receiving nil for the body and from attributes? I can't figure out what I'm doing wrong! The created and updated at are storing successfully but the two attributes that I care about continue to be stored as nil. Here's the Receive Text controller which is receiving the Post request from Twilio: class ReceiveTextController < ApplicationController def index @post=Post.create!(body: params[:Body], from: params[:From]) end end EDIT: When I dump the params I receive the following: "{\"controller\"=\"receive_text\", \"action\"=\"index\"}" I attained this by inserting the following into my ReceiveText controller. @params = Post.create!(body: params.inspect, from: "Dumping Params") and then opening up the Heroku console to find the database entry with from = "Dumping Params". I simulated a Twilio request with a curl with the following command curl -X POST myurl.com/receivetext route -d 'AccountSid=AC123&From=%2B19252411234' I checked the production database again and noticed that the curl request did work when obtaining the FROM atribute. It stored the following: params.inspect returned "{\"AccountSid\"=\"AC123\", \"From\"=\"+19252411234\", \"co..." I received a comment stating: "As long as twilio is hitting the same URL with the same method (GET/POST) it should be filling the params array as well" I have no idea how to make this comment actionable. Any help would be greatly appreciated! I'm very new to rails. Here's my database migration (I have both attributes set to string. I have tried setting it to text and that didn't work either) : class CreatePosts < ActiveRecord::Migration def change create_table :posts do |t| t.string :body t.string :from t.timestamps end end end Here is my Post model: class Post < ActiveRecord::Base attr_accessible :body, :from end Routes (everything appears to be routing just fine) : MovieApp::Application.routes.draw do get "receive_text/index" get "pages/home" get "send_text/send_text_message" root to: 'pages#home' match '/receivetext', to: 'receive_text#index' match '/pages/home', to: 'pages#home' match '/sendtext', to: 'send_text#send_text_message' end Here's my gemfile (incase it helps) source 'https://rubygems.org' gem 'rails', '3.2.3' gem 'badfruit' gem 'twilio-ruby' gem 'logger' gem 'jquery-rails' group :production do gem 'pg' end group :development, :test do gem 'sqlite3' end group :assets do gem 'sass-rails', '~> 3.2.3' gem 'coffee-rails', '~> 3.2.1' gem 'uglifier', '>= 1.0.3' end

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• Dependency Injection: I don't get where to start!

  - by Andy

  I have several articles about Dependency Injection, and I can see the benefits, especially when it comes to unit testing. The units can me loosely coupled, and mocking of dependencies can be made. The trouble is - I just don't get where to start. Consider this snippet below of (much edited for the purpose of this post) code that I have. I am instantiating a Plc object from the main form, and passing in a communications mode via the Connect method. In it's present form it becomes hard to test, because I can't isolate the Plc from the CommsChannel to unit test it. (Can I?) The class depends on using a CommsChannel object, but I am only passing in a mode that is used to create this channel within the Plc itself. To use dependancy injection, I should really pass in an already created CommsChannel (via an 'ICommsChannel' interface perhaps) to the Connect method, or maybe via the Plc constructor. Is that right? But then that would mean creating the CommsChannel in my main form first, and this doesn't seem right either, because it feels like everything will come back to the base layer of the main form, where everything begins. Somehow it feels like I am missing a crucial piece of the puzzle. Where do you start? You have to create an instance of something somewhere, but I'm struggling to understand where that should be. public class Plc() { public bool Connect(CommsMode commsMode) { bool success = false; // Create new comms channel. this._commsChannel = this.GetCommsChannel(commsMode); // Attempt connection success = this._commsChannel.Connect(); return this._connected; } private CommsChannel GetCommsChannel(CommsMode mode) { CommsChannel channel; switch (mode) { case CommsMode.RS232: channel = new SerialCommsChannel( SerialCommsSettings.Default.ComPort, SerialCommsSettings.Default.BaudRate, SerialCommsSettings.Default.DataBits, SerialCommsSettings.Default.Parity, SerialCommsSettings.Default.StopBits); break; case CommsMode.Tcp: channel = new TcpCommsChannel( TCPCommsSettings.Default.IP_Address, TCPCommsSettings.Default.Port); break; default: // Throw unknown comms channel exception. } return channel; } }

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• Classes to Entities; Like-class inheritence problems

  - by Stacey

  Beyond work, some friends and I are trying to build a game of sorts; The way we structure some of it works pretty well for a normal object oriented approach, but as most developers will attest this does not always translate itself well into a database persistent approach. This is not the absolute layout of what we have, it is just a sample model given for sake of representation. The whole project is being done in C# 4.0, and we have every intention of using Entity Framework 4.0 (unless Fluent nHibernate can really offer us something we outright cannot do in EF). One of the problems we keep running across is inheriting things in database models. Using the Entity Framework designer, I can draw the same code I have below; but I'm sure it is pretty obvious that it doesn't work like it is expected to. To clarify a little bit; 'Items' have bonuses, which can be of anything. Therefore, every part of the game must derive from something similar so that no matter what is 'changed' it is all at a basic enough level to be hooked into. Sounds fairly simple and straightforward, right? So then, we inherit everything that pertains to the game from 'Unit'. Weights, Measures, Random (think like dice, maybe?), and there will be other such entities. Some of them are similar, but in code they will each react differently. We're having a really big problem with abstracting this kind of thing into a database model. Without 'Enum' support, it is proving difficult to translate into multiple tables that still share a common listing. One solution we've depicted is to use a 'key ring' type approach, where everything that attaches to a character is stored on a 'Ring' with a 'Key', where each Key has a Value that represents a type. This works functionally but we've discovered it becomes very sluggish and performs poorly. We also dislike this approach because it begins to feel as if everything is 'dumped' into one class; which makes management and logical structure difficult to adhere to. I was hoping someone else might have some ideas on what I could do with this problem. It's really driving me up the wall; To summarize; the goal is to build a type (Unit) that can be used as a base type (Table per Type) for generic reference across a relatively global scope, without having to dump everything into a single collection. I can use an Interface to determine actual behavior so that isn't too big of an issue. This is 'roughly' the same idea expressed in the Entity Framework.

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• Virtual member call in a constructor when assigning value to property

  - by comecme

  I have an Abstract class and a Derived class. The abstract class defines an abstract property named Message. In the derived class, the property is implemented by overriding the abstract property. The constructor of the derived class takes a string argument and assigns it to its Message property. In Resharper, this assignment leads to a warning "Virtual member call in constructor". The AbstractClass has this definition: public abstract class AbstractClass { public abstract string Message { get; set; } protected AbstractClass() { } public abstract void PrintMessage(); } And the DerivedClass is as follows: using System; public class DerivedClass : AbstractClass { private string _message; public override string Message { get { return _message; } set { _message = value; } } public DerivedClass(string message) { Message = message; // Warning: Virtual member call in a constructor } public DerivedClass() : this("Default DerivedClass message") {} public override void PrintMessage() { Console.WriteLine("DerivedClass PrintMessage(): " + Message); } } I did find some other questions about this warning, but in those situations there is an actual call to a method. For instance, in this question, the answer by Matt Howels contains some sample code. I'll repeat it here for easy reference. class Parent { public Parent() { DoSomething(); } protected virtual void DoSomething() {}; } class Child : Parent { private string foo; public Child() { foo = "HELLO"; } protected override void DoSomething() { Console.WriteLine(foo.ToLower()); } } Matt doesn't describe on what error the warning would appear, but I'm assuming it will be on the call to DoSomething in the Parent constructor. In this example, I understand what is meant by a virtual member being called. The member call occurs in the base class, in which only a virtual method exists. In my situation however, I don't see why assigning a value to Message would be calling a virtual member. Both the call to and the implementation of the Message property are defined in the derived class. Although I can get rid of the error by making my Derived Class sealed, I would like to understand why this situation is resulting in the warning.

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• SVN: Branches for Every Little Change?

  - by yar

  Hi. We have a client (who has a client, who has a client) who is driving us mad with change requests to a code base (in PHP). Our first response was to just work in a main trunk in SVN, but the client often comes back and requests that a certain change needs to get pushed to the live servers ASAP. On the other hand, other changes get reduced in priority suddenly, which originally came grouped with other changes (seemingly). We are thinking of using a branch for every change request. Is this mad? What other solutions might work? Thanks! Edit: This is a really hard question to choose the correct answer for. Thanks to everybody for your great answers. Edit: I know that the best answer I chose was not particularly popular. I too wanted to find a technical solution to this problem. But now I think that if the client wants software with features that can be deployed in a modular fashion... this problem should not be solved in our use of the version control system. It would have to be designed into the software. Edit: Now it's almost a month later and my coworker/client has convinced me that multiple branches is the way to go. This is not just due to the client's insanity, but also based on our need to be able to determine if a feature is "ready to go" or "needs more work" or whatever. I don't have the SVN with me, but we merge using the advice from the SVN Cookbook: you merge the branch from the revision it was branched to the head revision. Also, using this system, we merge all branches at some point and that becomes the new QA and then live build. Then we branch from that. Last Edit (Perhaps): Months later, this system is still working out for us. We create branches for every ticket and rarely have problems. On the other hand, we do try to keep things separate as far as what people are working on... Two Years Later: We use GIT now, and now this system is actually quite reasonable.

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