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  • ADO Exception in HQL query

    - by Yoav
    I have 2 classes: Project and DataStructure. Class Project contains member List<DataStructure. My goal is to load a Project and all its DataStructures in one call. public class Project { public virtual string Id { get { } set { } } public virtual string Name { get { } set { } } public virtual ISet<DataStructure> DataStructures { get { } set { } } } public class DataStructure { public virtual string Id { get { } set { } } public virtual string Name { get { } set { } } public virtual string Description { get { } set { } } public virtual Project Project { get { } set { } } public virtual IList<DataField> Fields { get { } set { } } } Note that DataStructure also contains a list of class DataField but I don’t want to load these right now. Mapping in Fluent NHibernate: public class ProjectMap : ClassMap<Project> { public ProjectMap() { Table("PROJECTS"); Id(x => x.Pk, "PK"); Map(x => x.Id, "ID"); Map(x => x.Name, "NAME"); HasMany<DataStructure>(x => x.DataStructures).KeyColumn("FK_PROJECT"); } } public class DataStructureMap : ClassMap<DataStructure> { public DataStructureMap() { Table("DATA_STRUCTURES"); Map(x => x.Id, "ID"); Map(x => x.Name, "NAME"); Map(x => x.Description, "DESCRIPTION"); References<Project>(x => x.Project, "FK_PROJECT"); HasMany<DataField>(x => x.Fields).KeyColumn("FK_DATA_STRUCTURE"); } } This is my query: using (ISession session = SessionFactory.OpenSession()) { IQuery query = session.CreateQuery("from Project pr left join pr.DataStructure"); project = query.List<Project>(); } query.List() returns this exception: NHibernate.Exceptions.GenericADOException: Could not execute query[SQL: SQL not available] ---> System.ArgumentException: The value "System.Object[]" is not of type "Project" and cannot be used in this generic collection.

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  • [C++] std::string manipulation: whitespace, "newline escapes '\'" and comments #

    - by rubenvb
    Kind of looking for affirmation here. I have some hand-written code, which I'm not shy to say I'm proud of, which reads a file, removes leading whitespace, processes newline escapes '\' and removes comments starting with #. It also removes all empty lines (also whitespace-only ones). Any thoughts/recommendations? I could probably replace some std::cout's with std::runtime_errors... but that's not a priority here :) const int RecipeReader::readRecipe() { ifstream is_recipe(s_buffer.c_str()); if (!is_recipe) cout << "unable to open file" << endl; while (getline(is_recipe, s_buffer)) { // whitespace+comment removeLeadingWhitespace(s_buffer); processComment(s_buffer); // newline escapes + append all subsequent lines with '\' processNewlineEscapes(s_buffer, is_recipe); // store the real text line if (!s_buffer.empty()) v_s_recipe.push_back(s_buffer); s_buffer.clear(); } is_recipe.close(); return 0; } void RecipeReader::processNewlineEscapes(string &s_string, ifstream &is_stream) { string s_temp; size_t sz_index = s_string.find_first_of("\\"); while (sz_index <= s_string.length()) { if (getline(is_stream,s_temp)) { removeLeadingWhitespace(s_temp); processComment(s_temp); s_string = s_string.substr(0,sz_index-1) + " " + s_temp; } else cout << "Error: newline escape '\' found at EOF" << endl; sz_index = s_string.find_first_of("\\"); } } void RecipeReader::processComment(string &s_string) { size_t sz_index = s_string.find_first_of("#"); s_string = s_string.substr(0,sz_index); } void RecipeReader::removeLeadingWhitespace(string &s_string) { const size_t sz_length = s_string.size(); size_t sz_index = s_string.find_first_not_of(" \t"); if (sz_index <= sz_length) s_string = s_string.substr(sz_index); else if ((sz_index > sz_length) && (sz_length != 0)) // "empty" lines with only whitespace s_string.clear(); } Some extra info: the first s_buffer passed to the ifstream contains the filename, std::string s_buffer is a class data member, so is std::vector v_s_recipe. Any comment is welcome :)

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  • Why does every thread in my application use a different hibernate session?

    - by Ittai
    Hi, I have a web-application which uses hibernate and for some reason every thread (httprequest or other threads related to queueing) uses a different session. I've implemented a HibernateSessionFactory class which looks like this: public class HibernateSessionFactory { private static final ThreadLocal<Session> threadLocal = new ThreadLocal<Session>(); private static Configuration configuration = new AnnotationConfiguration(); private static org.hibernate.SessionFactory sessionFactory; static { try { configuration.configure(configFile); sessionFactory = configuration.buildSessionFactory(); } catch (Exception e) {} } private HibernateSessionFactory() {} public static Session getSession() throws HibernateException { Session session = (Session) threadLocal.get(); if (session == null || !session.isOpen()) { if (sessionFactory == null) { rebuildSessionFactory();//This method basically does what the static init block does } session = (sessionFactory != null) ? sessionFactory.openSession(): null; threadLocal.set(session); } return session; } //More non relevant methods here. Now from my testing it seems that the threadLocal member is indeed initialized only once when the class is first loaded by the JVM but for some reason when different threads access the getSession() method they use different sessions. When a thread first accesses this class (Session) threadLocal.get(); will return null but as expected all other access requests will yeild the same session. I'm not sure how this can be happening as the threadLocal variable is final and the method threadLocal.set(session) is only used in the above context (which I'm 99.9% sure has to yeild a non null session as I would have encountered a NullPointerException at a different part of my app). I'm not sure this is relevant but these are the main parts of my hibernate.cfg.xml file: <hibernate-configuration> <session-factory> <property name="connection.url">someURL</property> <property name="connection.driver_class"> com.microsoft.sqlserver.jdbc.SQLServerDriver</property> <property name="dialect">org.hibernate.dialect.SQLServerDialect</property> <property name="hibernate.connection.isolation">1</property> <property name="hibernate.connection.username">User</property> <property name="hibernate.connection.password">Password</property> <property name="hibernate.connection.pool_size">10</property> <property name="show_sql">false</property> <property name="current_session_context_class">thread</property> <property name="hibernate.hbm2ddl.auto">update</property> <property name="hibernate.cache.use_second_level_cache">false</property> <property name="hibernate.cache.provider_class">org.hibernate.cache.NoCacheProvider</property> <!-- Mapping files --> I'd appreciate any help granted and of course if anyone has any questions I'd be happy to clarify. Ittai

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  • Flex Air HTMLLoader blank pop up window when flash content is loaded

    - by user128938
    I have a flex Air program that loads external content with the HTMLLoader. Now for some reason whenever I load a page that has any flash content a blank system window pops up outside of my program. It's completely blank, all white with min, max and close buttons. If I close it any flash content I loaded stops working. For the life of my I can't figure out what's happening and there's no messages in the console and no title for the window. Does anyone have any ideas? I appreciate any help you can give. Here's the code I'm using: private var webPage:HTMLLoader; private function registerEvents():void { this.addEventListener(gameLoadEvent.GAME_LOAD, gameLoad); //webPage = new HTMLLoader(); } //function called back from Game Command to load correct game private function gameLoad(event:Event):void { var gameEvent:gameLoadEvent = event as gameLoadEvent; loadgame(gameEvent.url, gameEvent.variables); } private function loadgame(url:String, variableString:String):void { DesktopModelLocator.getInstance().scaleX = 1; DesktopModelLocator.getInstance().scaleY = 1; //var url:String = "http://pro-us.sbt-corp.com/aspx/member/LaunchGame.aspx"; var request:URLRequest = new URLRequest(url); //var variables:URLVariables = new URLVariables("gameNum=17&as=as1&t=demo&package=a&btnQuit=0"); if(variableString != null && variableString != ""){ var variables:URLVariables = new URLVariables(variableString); variables.exampleSessionId = new Date().getTime(); variables.exampleUserLabel = "guest"; request.data = variables; } webPage = HTMLLoader.createRootWindow(true, null, true, null); webPage.height = systemManager.stage.nativeWindow.height - 66; webPage.width = systemManager.stage.nativeWindow.width; webPage.load(request); webPage.navigateInSystemBrowser = false; flexBrowser.addChild(webPage); } ]]> </mx:Script> <mx:HTML id="flexBrowser" width="1366" height="658" backgroundAlpha="0.45" creationComplete="registerEvents();" x="0" y="0"> </mx:HTML>

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  • Form validation with optional File Upload field callback

    - by MotiveKyle
    I have a form with some input fields and a file upload field in the same form. I am trying to include a callback into the form validation to check for file upload errors. Here is the controller for adding and the callback: public function add() { if ($this->ion_auth->logged_in()): //validate form input $this->form_validation->set_rules('title', 'title', 'trim|required|max_length[66]|min_length[2]'); // link url $this->form_validation->set_rules('link', 'link', 'trim|required|max_length[255]|min_length[2]'); // optional content $this->form_validation->set_rules('content', 'content', 'trim|min_length[2]'); $this->form_validation->set_rules('userfile', 'image', 'callback_validate_upload'); $this->form_validation->set_error_delimiters('<small class="error">', '</small>'); // if form was submitted, process form if ($this->form_validation->run()) { // add pin $pin_id = $this->pin_model->create(); $slug = strtolower(url_title($this->input->post('title'), TRUE)); // path to pin folder $file_path = './uploads/' . $pin_id . '/'; // if folder doesn't exist, create it if (!is_dir($file_path)) { mkdir($file_path); } // file upload config variables $config['upload_path'] = $file_path; $config['allowed_types'] = 'jpg|png'; $config['max_size'] = '2048'; $config['max_width'] = '1920'; $config['max_height'] = '1080'; $config['encrypt_name'] = TRUE; $this->load->library('upload', $config); // upload image file if ($this->upload->do_upload()) { $this->load->model('file_model'); $image_id = $this->file_model->insert_image_to_db($pin_id); $this->file_model->add_image_id_to_pin($pin_id, $image_id); } } // build page else: // User not logged in redirect("login", 'refresh'); endif; } The callback: function validate_upload() { if ($_FILES AND $_FILES['userfile']['name']): if ($this->upload->do_upload()): return true; else: $this->form_validation->set_message('validate_upload', $this->upload->display_errors()); return false; endif; else: return true; endif; } I am getting the error Fatal error: Call to a member function do_upload() on a non-object on line 92 when I try to run this. Line 92 is the if ($this->upload->do_upload()): line in the validate_upload callback. Am I going about this the right way? What's triggering this error?

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  • Why do we have reinterpret_cast in C++ when two chained static_cast can do it's job?

    - by Nawaz
    Say I want to cast A* to char* and vice-versa, we have two choices (I mean, many of us think we've two choices, because both seems to work! Hence the confusion!): struct A { int age; char name[128]; }; A a; char *buffer = static_cast<char*>(static_cast<void*>(&a)); //choice 1 char *buffer = reinterpret_cast<char*>(&a); //choice 2 Both work fine. //convert back A *pA = static_cast<A*>(static_cast<void*>(buffer)); //choice 1 A *pA = reinterpret_cast<A*>(buffer); //choice 2 Even this works fine! So why do we have reinterpret_cast in C++ when two chained static_cast can do it's job? Some of you might think this topic is a duplicate of the previous topics such as listed at the bottom of this post, but it's not. Those topics discuss only theoretically, but none of them gives even a single example demonstrating why reintepret_cast is really needed, and two static_cast would surely fail. I agree, one static_cast would fail. But how about two? If the syntax of two chained static_cast looks cumbersome, then we can write a function template to make it more programmer-friendly: template<class To, class From> To any_cast(From v) { return static_cast<To>(static_cast<void*>(v)); } And then we can use this, as: char *buffer = any_cast<char*>(&a); //choice 1 char *buffer = reinterpret_cast<char*>(&a); //choice 2 //convert back A *pA = any_cast<A*>(buffer); //choice 1 A *pA = reinterpret_cast<A*>(buffer); //choice 2 Also, see this situation where any_cast can be useful: Proper casting for fstream read and write member functions. So my question basically is, Why do we have reinterpret_cast in C++? Please show me even a single example where two chained static_cast would surely fail to do the same job? Which cast to use; static_cast or reinterpret_cast? Cast from Void* to TYPE* : static_cast or reinterpret_cast

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  • TestNG - Factories and Dataproviders

    - by Tim K
    Background Story I'm working at a software firm developing a test automation framework to replace our old spaghetti tangled system. Since our system requires a login for almost everything we do, I decided it would be best to use @BeforeMethod, @DataProvider, and @Factory to setup my tests. However, I've run into some issues. Sample Test Case Lets say the software system is a baseball team roster. We want to test to make sure a user can search for a team member by name. (Note: I'm aware that BeforeMethods don't run in any given order -- assume that's been taken care of for now.) @BeforeMethod public void setupSelenium() { // login with username & password // acknowledge announcements // navigate to search page } @Test(dataProvider="players") public void testSearch(String playerName, String searchTerm) { // search for "searchTerm" // browse through results // pass if we find playerName // fail (Didn't find the player) } This test case assumes the following: The user has already logged on (in a BeforeMethod, most likely) The user has already navigated to the search page (trivial, before method) The parameters to the test are associated with the aforementioned login The Problems So lets try and figure out how to handle the parameters for the test case. Idea #1 This method allows us to associate dataproviders with usernames, and lets us use multiple users for any specific test case! @Test(dataProvider="players") public void testSearch(String user, String pass, String name, String search) { // login with user/pass // acknowledge announcements // navigate to search page // ... } ...but there's lots of repetition, as we have to make EVERY function accept two extra parameters. Not to mention, we're also testing the acknowledge announcements feature, which we don't actually want to test. Idea #2 So lets use the factory to initialize things properly! class BaseTestCase { public BaseTestCase(String user, String password, Object[][] data); } class SomeTest { @Factory public void ... } With this, we end up having to write one factory per test case... Although, it does let us have multiple users per test-case. Conclusion I'm about fresh out of ideas. There was another idea I had where I was loading data from an XML file, and then calling the methods from a program... but its getting silly. Any ideas?

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  • Deleting a node in a family tree

    - by user559142
    Hi, I'm trying to calclulate the best way to delete a node in a family tree. First, a little description of how the app works. My app makes the following assumption: Any node can only have one partner. That means that any child a single node has, it will also be the partner nodes child too. Therefore, step relations, divorces etc aren't compensated for. A node always has two parents - A mother and father cannot be added seperately. If the user doesn't know the details - the nodes attributes are set to a default value. Also any node can add parents, siblings, children to itself. Therefore in law relationships can be added. I have the following classes: FamilyMember String fName; String lName; String dob; String gender; FamilyMember mother, father, partner; ArrayListchildren; int index; int generation; void linkParents(); void linkPartner(); void addChild(); //gets & sets for fields Family ArrayListfamily; void addMember(); void removeMember(); FamilyMember getFamilyMember(index); ArrayListgetFamilyMembers(); FamilyTree Family family; void removeMember(); //need help void displayFamilyMembers(); void addFamilyMember(); void enterDetails(); void displayAncestors(); void displayDescendants(); void printDescendants(); FamilyMember findRootNode(); void sortGenerations(); void getRootGeneration(); I am having trouble with identifying the logic for removing a member. All other functions work fine. Has anyone developed a family tree app before who knows how to deal with removing various different nodes in the family "tree"? e.g. removing a leaf removing a leaf with partner (what if partner has parents etc) removing a parent It seems to be another recursive property but my head is swelling from over thought.

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  • CultureManager issue

    - by Serge
    I have a bug I don't understand. While the following works fine: Resources.Classes.AFieldFormula.DirectFieldFormula this one throws an exception: new ResourceManager(typeof(Resources.Classes.AFieldFormula)).GetString("DirectFieldFormula"); Could not find any resources appropriate for the specified culture or the neutral culture. Make sure \"Resources.Classes.AFieldFormula.resources\" was correctly embedded or linked into assembly \"MygLogWeb\" at compile time, or that all the satellite assemblies required are loadable and fully signed. How comes? Resource designer.cs file: //------------------------------------------------------------------------------ // <auto-generated> // This code was generated by a tool. // Runtime Version:4.0.30319.18408 // // Changes to this file may cause incorrect behavior and will be lost if // the code is regenerated. // </auto-generated> //------------------------------------------------------------------------------ namespace Resources.Classes { using System; /// <summary> /// A strongly-typed resource class, for looking up localized strings, etc. /// </summary> // This class was auto-generated by the StronglyTypedResourceBuilder // class via a tool like ResGen or Visual Studio. // To add or remove a member, edit your .ResX file then rerun ResGen // with the /str option, or rebuild your VS project. [global::System.CodeDom.Compiler.GeneratedCodeAttribute("System.Resources.Tools.StronglyTypedResourceBuilder", "4.0.0.0")] [global::System.Diagnostics.DebuggerNonUserCodeAttribute()] [global::System.Runtime.CompilerServices.CompilerGeneratedAttribute()] public class AFieldFormula { private static global::System.Resources.ResourceManager resourceMan; private static global::System.Globalization.CultureInfo resourceCulture; [global::System.Diagnostics.CodeAnalysis.SuppressMessageAttribute("Microsoft.Performance", "CA1811:AvoidUncalledPrivateCode")] internal AFieldFormula() { } /// <summary> /// Returns the cached ResourceManager instance used by this class. /// </summary> [global::System.ComponentModel.EditorBrowsableAttribute(global::System.ComponentModel.EditorBrowsableState.Advanced)] public static global::System.Resources.ResourceManager ResourceManager { get { if (object.ReferenceEquals(resourceMan, null)) { global::System.Resources.ResourceManager temp = new global::System.Resources.ResourceManager("MygLogWeb.Classes.AFieldFormula", typeof(AFieldFormula).Assembly); resourceMan = temp; } return resourceMan; } } /// <summary> /// Overrides the current thread's CurrentUICulture property for all /// resource lookups using this strongly typed resource class. /// </summary> [global::System.ComponentModel.EditorBrowsableAttribute(global::System.ComponentModel.EditorBrowsableState.Advanced)] public static global::System.Globalization.CultureInfo Culture { get { return resourceCulture; } set { resourceCulture = value; } } /// <summary> /// Looks up a localized string similar to Direct field. /// </summary> public static string DirectFieldFormula { get { return ResourceManager.GetString("DirectFieldFormula", resourceCulture); } } } }

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  • Wierdness debugging Visual Studio C++ 2008

    - by Jeff Dege
    I have a legacy C++ app, that in its most incarnation we've been building with makefiles and VS2003's command-line tool. I'm trying to get it to build using VS2008 and MsBuild. The build is working OK, but I'm getting errors where I'd never seen errors, before, and stepping through in VS2008's debugger only confuses me. The app links a number of static libraries, which fall into two categories: those that are part of the same application suite, and those that are shared between a number of application suites. Originally, I had a .csproj file for each static library, and two .sln files, one for the application suite (including the suite-specific libraries) and one for the non-suite-specific shared libraries. The shared libraries were included in the link, their projects were not included in the application suite .sln. The application instantiates an object from a class that is defined in one of the shared libraries. The class has a member object of a class that wraps a linked list. The constructor of the linked list class sets its "head" pointer to null. When I run the app, and try to add an element to the linked list, I get an error - the head pointer contains the value 0xCCCCCCCC. So I step through with the debugger. And see weirdness. When the current line in the debugger is in a source file belonging to the static library, the head pointer contains 0x00000000. When I step into the constructor, I can see the pointer being set to that value, and when I'm stepped into any other method of the class, I can see that the head pointer still contains 0x00000000. But when I step out into methods that are defined in the application suite .sln, it contains 0xCCCCCCCC. It's not like it's being overwritten. It changes back and forth depending upon which source file I am currently debugging. So I included the shared library's project in the application suite .sln, and now I see the head pointer containing 0xCCCCCCCC all the time. It looks like the constructor of the linked list class is not being called. So now, I'm entirely confused. Anyone have any ideas?

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  • [C++] Multiple inheritance from template class

    - by Tom P.
    Hello, I'm having issues with multiple inheritance from different instantiations of the same template class. Specifically, I'm trying to do this: template <class T> class Base { public: Base() : obj(NULL) { } virtual ~Base() { if( obj != NULL ) delete obj; } template <class T> T* createBase() { obj = new T(); return obj; } protected: T* obj; }; class Something { // ... }; class SomethingElse { // ... }; class Derived : public Base<Something>, public Base<SomethingElse> { }; int main() { Derived* d = new Derived(); Something* smth1 = d->createBase<Something>(); SomethingElse* smth2 = d->createBase<SomethingElse>(); delete d; return 0; } When I try to compile the above code, I get the following errors: 1>[...](41) : error C2440: '=' : cannot convert from 'SomethingElse *' to 'Something *' 1> Types pointed to are unrelated; conversion requires reinterpret_cast, C-style cast or function-style cast 1> [...](71) : see reference to function template instantiation 'T *Base<Something>::createBase<SomethingElse>(void)' being compiled 1> with 1> [ 1> T=SomethingElse 1> ] 1>[...](43) : error C2440: 'return' : cannot convert from 'Something *' to 'SomethingElse *' 1> Types pointed to are unrelated; conversion requires reinterpret_cast, C-style cast or function-style cast The issue seems to be ambiguity due to member obj being inherited from both Base< Something and Base< SomethingElse , and I can work around it by disambiguating my calls to createBase: Something* smth1 = d->Base<Something>::createBase<Something>(); SomethingElse* smth2 = d->Base<SomethingElse>::createBase<SomethingElse>(); However, this solution is dreadfully impractical, syntactically speaking, and I'd prefer something more elegant. Moreover, I'm puzzled by the first error message. It seems to imply that there is an instantiation createBase< SomethingElse in Base< Something , but how is that even possible? Any information or advice regarding this issue would be much appreciated.

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  • Is it any loose coupling mechanism in Objective-C + Cocoa like C# delegates or C++Qt signals+slots?

    - by Eye of Hell
    Hello. For a large programs, the standard way to chalenge a complexity is to divide a program code into small objects. Most of the actual programming languages offer this functionality via classes, so is Objective-C. But after source code is separated into small object, the second challenge is to somehow connect them with each over. Standard approaches, supported by most languages are compositon (one object is a member field of another), inheritance, templates (generics) and callbacks. More cryptic techniques include method-level delagates (C#) and signals+slots (C++Qt). I like the delegates / signals idea, since while connecting two objects i can connect individual methods with each over, without objects knowing anything of each over. For C#, it will look like this: var object1 = new CObject1(); var object2 = new CObject2(); object1.SomethingHappened += object2.HandleSomething; In this code, is object1 calls it's SomethingHappened delegate (like a normal method call) the HandleSomething method of object2 will be called. For C++Qt, it will look like this: var object1 = new CObject1(); var object2 = new CObject2(); connect( object1, SIGNAL(SomethingHappened()), object2, SLOT(HandleSomething()) ); The result will be exactly the same. This technique has some advantages and disadvantages, but generally i like it more than interfaces since if program code base grows i can change connections and add new ones without creating tons of interfaces. After examination of Objective-C i havn't found any way to use this technique i like :(. It seems that Objective-C supports message passing perfectly well, but it requres for object1 to have a pointer to object2 in order to pass it a message. If some object needs to be connected to lots of other objects, in Objective-C i will be forced to give him pointers to each of the objects it must be connected. So, the question :). Is it any approach in Objective-C programming that will closely resemble delegate / signal+slot types of connection, not a 'give first object an entire pointer to second object so it can pass a message to it'. Method-level connections are a bit more preferable to me than object-level connection ^_^.

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  • Where are the function literals c++?

    - by academicRobot
    First of all, maybe literals is not the right term for this concept, but its the closest I could think of (not literals in the sense of functions as first class citizens). The idea is that when you make a conventional function call, it compiles to something like this: callq <immediate address> But if you make a function call using a function pointer, it compiles to something like this: mov <memory location>,%rax callq *%rax Which is all well and good. However, what if I'm writing a template library that requires a callback of some sort with a specified argument list and the user of the library is expected to know what function they want to call at compile time? Then I would like to write my template to accept a function literal as a template parameter. So, similar to template <int int_literal> struct my_template {...};` I'd like to write template <func_literal_t func_literal> struct my_template {...}; and have calls to func_literal within my_template compile to callq <immediate address>. Is there a facility in C++ for this, or a work around to achieve the same effect? If not, why not (e.g. some cataclysmic side effects)? How about C++0x or another language? Solutions that are not portable are fine. Solutions that include the use of member function pointers would be ideal. I'm not particularly interested in being told "You are a <socially unacceptable term for a person of low IQ>, just use function pointers/functors." This is a curiosity based question, and it seems that it might be useful in some (albeit limited) applications. It seems like this should be possible since function names are just placeholders for a (relative) memory address, so why not allow more liberal use (e.g. aliasing) of this placeholder. p.s. I use function pointers and functions objects all the the time and they are great. But this post got me thinking about the don't pay for what you don't use principle in relation to function calls, and it seems like forcing the use of function pointers or similar facility when the function is known at compile time is a violation of this principle, though a small one.

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  • Header Guard Issues - Getting Swallowed Alive

    - by gjnave
    I'm totally at wit's end: I can't figure out how my dependency issues. I've read countless posts and blogs and reworked my code so many times that I can't even remember what almost worked and what didnt. I continually get not only redefinition errors, but class not defined errors. I rework the header guards and remove some errors simply to find others. I somehow got everything down to one error but then even that got broke while trying to fix it. Would you please help me figure out the problem? card.cpp #include <iostream> #include <cctype> #include "card.h" using namespace std; // ====DECL====== Card::Card() { abilities = 0; flavorText = 0; keywords = 0; artifact = 0; classType = new char[strlen("Card") + 1]; classType = "Card"; } Card::~Card (){ delete name; delete abilities; delete flavorText; artifact = NULL; } // ------------ Card::Card(const Card & to_copy) { name = new char[strlen(to_copy.name) +1]; // creating dynamic array strcpy(to_copy.name, name); type = to_copy.type; color = to_copy.color; manaCost = to_copy.manaCost; abilities = new char[strlen(to_copy.abilities) +1]; strcpy(abilities, to_copy.abilities); flavorText = new char[strlen(to_copy.flavorText) +1]; strcpy(flavorText, to_copy.flavorText); keywords = new char[strlen(to_copy.keywords) +1]; strcpy(keywords, to_copy.keywords); inPlay = to_copy.inPlay; tapped = to_copy.tapped; enchanted = to_copy.enchanted; cursed = to_copy.cursed; if (to_copy.type != ARTIFACT) artifact = to_copy.artifact; } // ====DECL===== int Card::equipArtifact(Artifact* to_equip){ artifact = to_equip; } Artifact * Card::unequipArtifact(Card * unequip_from){ Artifact * to_remove = artifact; artifact = NULL; return to_remove; // put card in hand or in graveyard } int Card::enchant( Card * to_enchant){ to_enchant->enchanted = true; cout << "enchanted" << endl; } int Card::disenchant( Card * to_disenchant){ to_disenchant->enchanted = false; cout << "Enchantment Removed" << endl; } // ========DECL===== Spell::Spell() { currPower = basePower; currToughness = baseToughness; classType = new char[strlen("Spell") + 1]; classType = "Spell"; } Spell::~Spell(){} // --------------- Spell::Spell(const Spell & to_copy){ currPower = to_copy.currPower; basePower = to_copy.basePower; currToughness = to_copy.currToughness; baseToughness = to_copy.baseToughness; } // ========= int Spell::attack( Spell *& blocker ){ blocker->currToughness -= currPower; currToughness -= blocker->currToughness; } //========== int Spell::counter (Spell *& to_counter){ cout << to_counter->name << " was countered by " << name << endl; } // ============ int Spell::heal (Spell *& to_heal, int amountOfHealth){ to_heal->currToughness += amountOfHealth; } // ------- Creature::Creature(){ summoningSick = true; } // =====DECL====== Land::Land(){ color = NON; classType = new char[strlen("Land") + 1]; classType = "Land"; } // ------ int Land::generateMana(int mana){ // ... // } card.h #ifndef CARD_H #define CARD_H #include <cctype> #include <iostream> #include "conception.h" class Artifact; class Spell; class Card : public Conception { public: Card(); Card(const Card &); ~Card(); protected: char* name; enum CardType { INSTANT, CREATURE, LAND, ENCHANTMENT, ARTIFACT, PLANESWALKER}; enum CardColor { WHITE, BLUE, BLACK, RED, GREEN, NON }; CardType type; CardColor color; int manaCost; char* abilities; char* flavorText; char* keywords; bool inPlay; bool tapped; bool cursed; bool enchanted; Artifact* artifact; virtual int enchant( Card * ); virtual int disenchant (Card * ); virtual int equipArtifact( Artifact* ); virtual Artifact* unequipArtifact(Card * ); }; // ------------ class Spell: public Card { public: Spell(); ~Spell(); Spell(const Spell &); protected: virtual int heal( Spell *&, int ); virtual int attack( Spell *& ); virtual int counter( Spell*& ); int currToughness; int baseToughness; int currPower; int basePower; }; class Land: public Card { public: Land(); ~Land(); protected: virtual int generateMana(int); }; class Forest: public Land { public: Forest(); ~Forest(); protected: int generateMana(); }; class Creature: public Spell { public: Creature(); ~Creature(); protected: bool summoningSick; }; class Sorcery: public Spell { public: Sorcery(); ~Sorcery(); protected: }; #endif conception.h -- this is an "uber class" from which everything derives class Conception{ public: Conception(); ~Conception(); protected: char* classType; }; conception.cpp Conception::Conception{ Conception(){ classType = new char[11]; char = "Conception"; } game.cpp -- this is an incomplete class as of this code #include <iostream> #include <cctype> #include "game.h" #include "player.h" Battlefield::Battlefield(){ card = 0; } Battlefield::~Battlefield(){ delete card; } Battlefield::Battlefield(const Battlefield & to_copy){ } // =========== /* class Game(){ public: Game(); ~Game(); protected: Player** player; // for multiple players Battlefield* root; // for battlefield getPlayerMove(); // ask player what to do addToBattlefield(); removeFromBattlefield(); sendAttack(); } */ #endif game.h #ifndef GAME_H #define GAME_H #include "list.h" class CardList(); class Battlefield : CardList{ public: Battlefield(); ~Battlefield(); protected: Card* card; // make an array }; class Game : Conception{ public: Game(); ~Game(); protected: Player** player; // for multiple players Battlefield* root; // for battlefield getPlayerMove(); // ask player what to do addToBattlefield(); removeFromBattlefield(); sendAttack(); Battlefield* field; }; list.cpp #include <iostream> #include <cctype> #include "list.h" // ========== LinkedList::LinkedList(){ root = new Node; classType = new char[strlen("LinkedList") + 1]; classType = "LinkedList"; }; LinkedList::~LinkedList(){ delete root; } LinkedList::LinkedList(const LinkedList & obj) { // code to copy } // --------- // ========= int LinkedList::delete_all(Node* root){ if (root = 0) return 0; delete_all(root->next); root = 0; } int LinkedList::add( Conception*& is){ if (root == 0){ root = new Node; root->next = 0; } else { Node * curr = root; root = new Node; root->next=curr; root->it = is; } } int LinkedList::remove(Node * root, Node * prev, Conception* is){ if (root = 0) return -1; if (root->it == is){ root->next = root->next; return 0; } remove(root->next, root, is); return 0; } Conception* LinkedList::find(Node*& root, const Conception* is, Conception* holder = NULL) { if (root==0) return NULL; if (root->it == is){ return root-> it; } holder = find(root->next, is); return holder; } Node* LinkedList::goForward(Node * root){ if (root==0) return root; if (root->next == 0) return root; else return root->next; } // ============ Node* LinkedList::goBackward(Node * root){ root = root->prev; } list.h #ifndef LIST_H #define LIST_H #include <iostream> #include "conception.h" class Node : public Conception { public: Node() : next(0), prev(0), it(0) { it = 0; classType = new char[strlen("Node") + 1]; classType = "Node"; }; ~Node(){ delete it; delete next; delete prev; } Node* next; Node* prev; Conception* it; // generic object }; // ---------------------- class LinkedList : public Conception { public: LinkedList(); ~LinkedList(); LinkedList(const LinkedList&); friend bool operator== (Conception& thing_1, Conception& thing_2 ); protected: virtual int delete_all(Node*); virtual int add( Conception*& ); // virtual Conception* find(Node *&, const Conception*, Conception* ); // virtual int remove( Node *, Node *, Conception* ); // removes question with keyword int display_all(node*& ); virtual Node* goForward(Node *); virtual Node* goBackward(Node *); Node* root; // write copy constrcutor }; // ============= class CircularLinkedList : public LinkedList { public: // CircularLinkedList(); // ~CircularLinkedList(); // CircularLinkedList(const CircularLinkedList &); }; class DoubleLinkedList : public LinkedList { public: // DoubleLinkedList(); // ~DoubleLinkedList(); // DoubleLinkedList(const DoubleLinkedList &); protected: }; // END OF LIST Hierarchy #endif player.cpp #include <iostream> #include "player.h" #include "list.h" using namespace std; Library::Library(){ root = 0; } Library::~Library(){ delete card; } // ====DECL========= Player::~Player(){ delete fname; delete lname; delete deck; } Wizard::~Wizard(){ delete mana; delete rootL; delete rootH; } // =====Player====== void Player::changeName(const char[] first, const char[] last){ char* backup1 = new char[strlen(fname) + 1]; strcpy(backup1, fname); char* backup2 = new char[strlen(lname) + 1]; strcpy(backup1, lname); if (first != NULL){ fname = new char[strlen(first) +1]; strcpy(fname, first); } if (last != NULL){ lname = new char[strlen(last) +1]; strcpy(lname, last); } return 0; } // ========== void Player::seeStats(Stats*& to_put){ to_put->wins = stats->wins; to_put->losses = stats->losses; to_put->winRatio = stats->winRatio; } // ---------- void Player::displayDeck(const LinkedList* deck){ } // ================ void CardList::findCard(Node* root, int id, NodeCard*& is){ if (root == NULL) return; if (root->it.id == id){ copyCard(root->it, is); return; } else findCard(root->next, id, is); } // -------- void CardList::deleteAll(Node* root){ if (root == NULL) return; deleteAll(root->next); root->next = NULL; } // --------- void CardList::removeCard(Node* root, int id){ if (root == NULL) return; if (root->id = id){ root->prev->next = root->next; // the prev link of root, looks back to next of prev node, and sets to where root next is pointing } return; } // --------- void CardList::addCard(Card* to_add){ if (!root){ root = new Node; root->next = NULL; root->prev = NULL; root->it = &to_add; return; } else { Node* original = root; root = new Node; root->next = original; root->prev = NULL; original->prev = root; } } // ----------- void CardList::displayAll(Node*& root){ if (root == NULL) return; cout << "Card Name: " << root->it.cardName; cout << " || Type: " << root->it.type << endl; cout << " --------------- " << endl; if (root->classType == "Spell"){ cout << "Base Power: " << root->it.basePower; cout << " || Current Power: " << root->it.currPower << endl; cout << "Base Toughness: " << root->it.baseToughness; cout << " || Current Toughness: " << root->it.currToughness << endl; } cout << "Card Type: " << root->it.currPower; cout << " || Card Color: " << root->it.color << endl; cout << "Mana Cost" << root->it.manaCost << endl; cout << "Keywords: " << root->it.keywords << endl; cout << "Flavor Text: " << root->it.flavorText << endl; cout << " ----- Class Type: " << root->it.classType << " || ID: " << root->it.id << " ----- " << endl; cout << " ******************************************" << endl; cout << endl; // ------- void CardList::copyCard(const Card& to_get, Card& put_to){ put_to.type = to_get.type; put_to.color = to_get.color; put_to.manaCost = to_get.manaCost; put_to.inPlay = to_get.inPlay; put_to.tapped = to_get.tapped; put_to.class = to_get.class; put_to.id = to_get.id; put_to.enchanted = to_get.enchanted; put_to.artifact = to_get.artifact; put_to.class = to_get.class; put.to.abilities = new char[strlen(to_get.abilities) +1]; strcpy(put_to.abilities, to_get.abilities); put.to.keywords = new char[strlen(to_get.keywords) +1]; strcpy(put_to.keywords, to_get.keywords); put.to.flavorText = new char[strlen(to_get.flavorText) +1]; strcpy(put_to.flavorText, to_get.flavorText); if (to_get.class = "Spell"){ put_to.baseToughness = to_get.baseToughness; put_to.basePower = to_get.basePower; put_to.currToughness = to_get.currToughness; put_to.currPower = to_get.currPower; } } // ---------- player.h #ifndef player.h #define player.h #include "list.h" // ============ class CardList() : public LinkedList(){ public: CardList(); ~CardList(); protected: virtual void findCard(Card&); virtual void addCard(Card* ); virtual void removeCard(Node* root, int id); virtual void deleteAll(); virtual void displayAll(); virtual void copyCard(const Conception*, Node*&); Node* root; } // --------- class Library() : public CardList(){ public: Library(); ~Library(); protected: Card* card; int numCards; findCard(Card&); // get Card and fill empty template } // ----------- class Deck() : public CardList(){ public: Deck(); ~Deck(); protected: enum deckColor { WHITE, BLUE, BLACK, RED, GREEN, MIXED }; char* deckName; } // =============== class Mana(int amount) : public Conception { public: Mana() : displayTotal(0), classType(0) { displayTotal = 0; classType = new char[strlen("Mana") + 1]; classType = "Mana"; }; protected: int accrued; void add(); void remove(); int displayTotal(); } inline Mana::add(){ accrued += 1; } inline Mana::remove(){ accrued -= 1; } inline Mana::displayTotal(){ return accrued; } // ================ class Stats() : public Conception { public: friend class Player; friend class Game; Stats() : wins(0), losses(0), winRatio(0) { wins = 0; losses = 0; if ( (wins + losses != 0) winRatio = wins / (wins + losses); else winRatio = 0; classType = new char[strlen("Stats") + 1]; classType = "Stats"; } protected: int wins; int losses; float winRatio; void int getStats(Stats*& ); } // ================== class Player() : public Conception{ public: Player() : wins(0), losses(0), winRatio(0) { fname = NULL; lname = NULL; stats = NULL; CardList = NULL; classType = new char[strlen("Player") + 1]; classType = "Player"; }; ~Player(); Player(const Player & obj); protected: // member variables char* fname; char* lname; Stats stats; // holds previous game statistics CardList* deck[]; // hold multiple decks that player might use - put ll in this private: // member functions void changeName(const char[], const char[]); void shuffleDeck(int); void seeStats(Stats*& ); void displayDeck(int); chooseDeck(); } // -------------------- class Wizard(Card) : public Player(){ public: Wizard() : { mana = NULL; rootL = NULL; rootH = NULL}; ~Wizard(); protected: playCard(const Card &); removeCard(Card &); attackWithCard(Card &); enchantWithCard(Card &); disenchantWithCard(Card &); healWithCard(Card &); equipWithCard(Card &); Mana* mana[]; Library* rootL; // Library Library* rootH; // Hand } #endif

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  • Force deletion of slot in boost::signals2

    - by villintehaspam
    Hi! I have found that boost::signals2 uses sort of a lazy deletion of connected slots, which makes it difficult to use connections as something that manages lifetimes of objects. I am looking for a way to force slots to be deleted directly when disconnected. Any ideas on how to work around the problem by designing my code differently are also appreciated! This is my scenario: I have a Command class responsible for doing something that takes time asynchronously, looking something like this (simplified): class ActualWorker { public: boost::signals2<void ()> OnWorkComplete; }; class Command : boost::enable_shared_from_this<Command> { public: ... void Execute() { m_WorkerConnection = m_MyWorker.OnWorkDone.connect(boost::bind(&Command::Handle_OnWorkComplete, shared_from_this()); // launch asynchronous work here and return } boost::signals2<void ()> OnComplete; private: void Handle_OnWorkComplete() { // get a shared_ptr to ourselves to make sure that we live through // this function but don't keep ourselves alive if an exception occurs. shared_ptr<Command> me = shared_from_this(); // Disconnect from the signal, ideally deleting the slot object m_WorkerConnection.disconnect(); OnComplete(); // the shared_ptr now goes out of scope, ideally deleting this } ActualWorker m_MyWorker; boost::signals2::connection m_WorkerConnection; }; The class is invoked about like this: ... boost::shared_ptr<Command> cmd(new Command); cmd->OnComplete.connect( foo ); cmd->Execute(); // now go do something else, forget all about the cmd variable etcetera. the Command class keeps itself alive by getting a shared_ptr to itself which is bound to the ActualWorker signal using boost::bind. When the worker completes, the handler in Command is invoked. Now, since I would like the Command object to be destroyed, I disconnect from the signal as can be seen in the code above. The problem is that the actual slot object is not deleted when disconnected, it is only marked as invalid and then deleted at a later time. This in turn appears to depend on the signal to fire again, which it doesn't do in my case, leading to the slot never expiring. The boost::bind object thus never goes out of scope, holding a shared_ptr to my object that will never get deleted. I can work around this by binding using the this pointer instead of a shared_ptr and then keeping my object alive using a member shared_ptr which I then release in the handler function, but it kind of makes the design feel a bit overcomplicated. Is there a way to force signals2 to delete the slot when disconnecting? Or is there something else I could do to simplify the design? Any comments are appreciated!

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  • Subclassing and adding data members

    - by Marius
    I have an hierarchy of classes that looks like the following: class Critical { public: Critical(int a, int b) : m_a(a), m_b(b) { } virtual ~Critical() { } int GetA() { return m_a; } int GetB() { return m_b; } void SetA(int a) { m_a = a; } void SetB(int b) { m_b = b; } protected: int m_a; int m_b; }; class CriticalFlavor : public Critical { public: CriticalFlavor(int a, int b, int flavor) : Critical(a, b), m_flavor(flavor) { } virtual ~CriticalFlavor() { } int GetFlavor() { return m_flavor; } void SetFlavor(int flavor) { m_flavor = flavor; } protected: int m_flavor; }; class CriticalTwist : public Critical { public: CriticalTwist(int a, int b, int twist) : Critical(a, b), m_twist(twist) { } virtual ~CriticalTwist() { } int GetTwist() { return m_twist; } void SetTwist(int twist) { m_twist = twist; } protected: int m_twist; }; The above does not seem right to me in terms of the design and what bothers me the most is the fact that the addition of member variables seems to drive the interface of these classes (the real code that does the above is a little more complex but still embracing the same pattern). That will proliferate when in need for another "Critical" class that just adds some other property. Does this feel right to you? How could I refactor such code? An idea would be to have just a set of interfaces and use composition when it comes to the base object like the following: class Critical { public: virtual int GetA() = 0; virtual int GetB() = 0; virtual void SetA(int a) = 0; virtual void SetB(int b) = 0; }; class CriticalImpl { public: CriticalImpl(int a, int b) : m_a(a), m_b(b) { } ~CriticalImpl() { } int GetA() { return m_a; } int GetB() { return m_b; } void SetA(int a) { m_a = a; } void SetB(int b) { m_b = b; } private: int m_a; int m_b; }; class CriticalFlavor { public: virtual int GetFlavor() = 0; virtual void SetFlavor(int flavor) = 0; }; class CriticalFlavorImpl : public Critical, public CriticalFlavor { public: CriticalFlavorImpl(int a, int b, int flavor) : m_flavor(flavor), m_critical(new CriticalImpl(a, b)) { } ~CriticalFlavorImpl() { delete m_critical; } int GetFlavor() { return m_flavor; } void SetFlavor(int flavor) { m_flavor = flavor; } int GetA() { return m_critical-GetA(); } int GetB() { return m_critical-GetB(); } void SetA(int a) { m_critical-SetA(a); } void SetB(int b) { m_critical-SetB(b); } private: int m_flavor; CriticalImpl* m_critical; };

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  • I am unsure of how to access a persistence entity from a JSP page?

    - by pharma_joe
    Hi, I am just learning Java EE, I have created a Persistence entity for a User object, which is stored in the database. I am now trying to create a JSP page that will allow a client to enter a new User object into the System. I am unsure of how the JSP page interacts with the User facade, the tutorials are confusing me a little. This is the code for the facade: <html> <head> <meta http-equiv="Content-Type" content="text/html; charset=UTF-8"> <title>Add User to System</title> </head> <body> <h2>Add User</h2> <h3>Please fill out the details to add a user to the system</h3> <form action=""> <label>Email:</label> <input type="text" name="email"><br /> <label>Password:</label> <input type="password" name="name"><br /> <label>Name:</label> <input type="text" name="name"><br /> <label>Address:</label> <input type="text" name="address"><br /> <label>Type:</label> <select name="type"> <option>Administrator</option> <option>Member</option> </select><br /> <input type="submit" value="Add" name="add"/> <input type="reset" value="clear" /> </form> </body> This is the code I have to add a new User object within the User facade class: @Stateless public class CinemaUserFacade { @PersistenceContext(unitName = "MonashCinema-warPU") private EntityManager em; public void create(CinemaUser cinemaUser) { em.persist(cinemaUser); } I am finding it a little difficult to get my head around the whole MVC thing, getting there but would appreciate it if someone could turn the light on for me!

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  • C++ vector of strings, pointers to functions, and the resulting frustration.

    - by Kyle
    So I am a first year computer science student, for on of my final projects, I need to write a program that takes a vector of strings, and applies various functions to these. Unfortunately, I am really confused on how to use pointer to pass the vector from function to function. Below is some sample code to give an idea of what I am talking about. I also get an error message when I try to deference any pointer. thanks. #include <iostream> #include <cstdlib> #include <vector> #include <string> using namespace std; vector<string>::pointer function_1(vector<string>::pointer ptr); void function_2(vector<string>::pointer ptr); int main() { vector<string>::pointer ptr; vector<string> svector; ptr = &svector[0]; function_1(ptr); function_2(ptr); } vector<string>::pointer function_1(vector<string>::pointer ptr) { string line; for(int i = 0; i < 10; i++) { cout << "enter some input ! \n"; // i need to be able to pass a reference of the vector getline(cin, line); // through various functions, and have the results *ptr.pushback(line); // reflectedin main(). But I cannot use member functions } // of vector with a deferenced pointer. return(ptr); } void function_2(vector<string>::pointer ptr) { for(int i = 0; i < 10; i++) { cout << *ptr[i] << endl; } }

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  • HtmlHelperExtensions are not visible in view mvc3 asp.net

    - by user1299372
    I've added a class for the HTML Custom Extensions: using System; using System.Linq.Expressions; using System.Text; using System.Web.Mvc; using System.Web.Mvc.Html; namespace App.MvcHtmlHelpers { public static class HtmlHelperExtensions { public static MvcHtmlString ComboBox(HtmlHelper html, string name, SelectList items, string selectedValue) { var sb = new StringBuilder(); sb.Append(html.DropDownList(name + "_hidden", items, new { @style = "width: 200px;", @onchange = "$('input#" + name + "').val($(this).val());" })); sb.Append(html.TextBox(name, selectedValue, new { @style = "margin-left: -199px; width: 179px; height: 1.2em; border: 0;" })); return MvcHtmlString.Create(sb.ToString()); } public static MvcHtmlString ComboBoxFor<TModel, TProperty>(HtmlHelper<TModel> html, Expression<Func<TModel, TProperty>> expression, SelectList items) { var me = (MemberExpression)expression.Body; var name = me.Member.Name; var sb = new StringBuilder(); sb.Append(html.DropDownList(name + "_hidden", items, new { @style = "width: 200px;", @onchange = "$('input#" + name + "').val($(this).val());" })); sb.Append(html.TextBoxFor(expression, new { @style = "margin-left: -199px; width: 179px; height: 1.2em; border: 0;" })); return MvcHtmlString.Create(sb.ToString()); } I've also registered it in my site web config: <namespaces> <add namespace="System.Web.Helpers" /> <add namespace="System.Web.Mvc" /> <add namespace="System.Web.Mvc.Ajax" /> <add namespace="System.Web.Mvc.Html" /> <add namespace="System.Web.Routing" /> <add namespace="System.Web.WebPages" /> <add namespace="App.MvcHtmlHelpers"/> </namespaces> In my view, I import the namespace: <%@ Import Namespace="RSPWebApp.MvcHtmlHelpers" %> But when I go to call it in the view, it doesn't recognize the custom extension. Can someone help me by telling me what I might have missed? Thanks so much in advance! <%:Html.ComboBoxFor(a => a.Street2, streetAddressListItems) %

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  • Inbreeding-immune database structure

    - by Nick Savage
    I have an application that requires a "simple" family tree. I would like to be able to perform queries that will give me data for an entire family given one id from a member in the family. I say simple because it does not need to take into account adoption or any other obscurities. The requirements for the application are as follows: Any two people will not be able to breed if they're from the same genetic line Needs to allow for the addition of new family lines (new people with no previous family) Need to be able to pull siblings, parents separately through queries I'm having trouble coming up with the proper structure for the database. So far I've come up with two solutions but they're not very reliable and will probably get out of hand quite quickly. Solution 1 involves placing a family_ids field on the people table and storing a list of unique family ids. Each time two people breed the lists are checked against each other to make sure no ids match and if everything checks out will merge the two lists and set that as the child's family_ids field. Example: Father (family_ids: (null)) breeds with Mother (family_ids: (213, 519)) -> Child (family_ids: (213, 519)) breeds with Random Person (family_ids: (813, 712, 122, 767)) -> Grandchild (family_ids: (213, 519, 813, 712, 122, 767)) And so on and so forth... The problem I see with this is the lists becoming unreasonably large as time goes on. Solution 2 uses cakephp's associations to declare: public $belongsTo = array( 'Father' => array( 'className' => 'User', 'foreignKey' => 'father_id' ), 'Mother' => array( 'className' => 'User', 'foreignKey' => 'mother_id' ) ); Now setting recursive to 2 will fetch the results of the mother and father, along with their mother and father, and so on and so forth all the way down the line. The problem with this route is that the data is in nested arrays and I'm unsure of how to efficiently work through the code. If anyone would be able to steer me in the direction of the most efficient way to handle what I want to achieve that would be tremendously helpful. Any and all help is greatly appreciated and I'll gladly answer any questions anyone has. Thanks a lot.

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  • Is it a good or bad practice to call instance methods from a java constructor?

    - by Steve
    There are several different ways I can initialize complex objects (with injected dependencies and required set-up of injected members), are all seem reasonable, but have various advantages and disadvantages. I'll give a concrete example: final class MyClass { private final Dependency dependency; @Inject public MyClass(Dependency dependency) { this.dependency = dependency; dependency.addHandler(new Handler() { @Override void handle(int foo) { MyClass.this.doSomething(foo); } }); doSomething(0); } private void doSomething(int foo) { dependency.doSomethingElse(foo+1); } } As you can see, the constructor does 3 things, including calling an instance method. I've been told that calling instance methods from a constructor is unsafe because it circumvents the compiler's checks for uninitialized members. I.e. I could have called doSomething(0) before setting this.dependency, which would have compiled but not worked. What is the best way to refactor this? Make doSomething static and pass in the dependency explicitly? In my actual case I have three instance methods and three member fields that all depend on one another, so this seems like a lot of extra boilerplate to make all three of these static. Move the addHandler and doSomething into an @Inject public void init() method. While use with Guice will be transparent, it requires any manual construction to be sure to call init() or else the object won't be fully-functional if someone forgets. Also, this exposes more of the API, both of which seem like bad ideas. Wrap a nested class to keep the dependency to make sure it behaves properly without exposing additional API:class DependencyManager { private final Dependency dependency; public DependecyManager(Dependency dependency) { ... } public doSomething(int foo) { ... } } @Inject public MyClass(Dependency dependency) { DependencyManager manager = new DependencyManager(dependency); manager.doSomething(0); } This pulls instance methods out of all constructors, but generates an extra layer of classes, and when I already had inner and anonymous classes (e.g. that handler) it can become confusing - when I tried this I was told to move the DependencyManager to a separate file, which is also distasteful because it's now multiple files to do a single thing. So what is the preferred way to deal with this sort of situation?

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  • template; Point<2, double>; Point<3, double>

    - by Oops
    Hi, I want to create my own Point struct it is only for purposes of learning C++. I have the following code: template <int dims, typename T> struct Point { T X[dims]; Point(){} Point( T X0, T X1 ) { X[0] = X0; X[1] = X1; } Point( T X0, T X1, T X2 ) { X[0] = X0; X[1] = X1; X[2] = X2; } Point<dims, int> toint() { //how to distinguish between 2D and 3D ??? Point<dims, int> ret = Point<dims, int>( (int)X[0], (int)X[1]); return ret; } std::string str(){ //how to distinguish between 2D and 3D ??? std::stringstream s; s << "{ X0: " << X[0] << " | X1: " << X[1] << " }"; return s.str(); } }; int main(void) { Point<2, double> p2d = Point<2, double>( 12.3, 45.6 ); Point<3, double> p3d = Point<3, double>( 12.3, 45.6, 78.9 ); Point<2, int> p2i = p2d.toint(); //OK Point<3, int> p3i = p3d.toint(); //m??? std::cout << p2d.str() << std::endl; //OK std::cout << p3d.str() << std::endl; //m??? std::cout << p2i.str() << std::endl; //m??? std::cout << p3i.str() << std::endl; //m??? char c; std::cin >> c; return 0; } of couse until now the output is not what I want. my questions is: how to take care of the dimensions of the Point (2D or 3D) in member functions of the Point? many thanks in advance Oops

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  • Is it possible to create a C++ factory system that can create an instance of any "registered" object

    - by chrensli
    Hello, I've spent my entire day researching this topic, so it is with some scattered knowledge on the topic that i come to you with this inquiry. Please allow me to describe what I am attempting to accomplish, and maybe you can either suggest a solution to the immediate question, or another way to tackle the problem entirely. I am trying to mimic something related to how XAML files work in WPF, where you are essentially instantiating an object tree from an XML definition. If this is incorrect, please inform. This issue is otherwise unrelated to WPF, C#, or anything managed - I solely mention it because it is a similar concept.. So, I've created an XML parser class already, and generated a node tree based on ObjectNode objects. ObjectNode objects hold a string value called type, and they have an std::vector of child ObjectNode objects. The next step is to instantiate a tree of objects based on the data in the ObjectNode tree. This intermediate ObjectNode tree is needed because the same ObjectNode tree might be instantiated multiple times or delayed as needed. The tree of objects that is being created is such that the nodes in the tree are descendants of a common base class, which for now we can refer to as MyBase. Leaf nodes can be of any type, not necessarily derived from MyBase. To make this more challenging, I will not know what types of MyBase derived objects might be involved, so I need to allow for new types to be registered with the factory. I am aware of boost's factory. Their docs have an interesting little design paragraph on this page: o We may want a factory that takes some arguments that are forwarded to the constructor, o we will probably want to use smart pointers, o we may want several member functions to create different kinds of objects, o we might not necessarily need a polymorphic base class for the objects, o as we will see, we do not need a factory base class at all, o we might want to just call the constructor - without #new# to create an object on the stack, and o finally we might want to use customized memory management. I might not be understanding this all correctly, but that seems to state that what I'm trying to do can be accomplished with boost's factory. But all the examples I've located, seem to describe factories where all objects are derived from a base type. Any guidance on this would be greatly appreciated. Thanks for your time!

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  • avoiding enums as interface identifiers c++ OOP

    - by AlasdairC
    Hi I'm working on a plugin framework using dynamic loaded shared libraries which is based on Eclipse's (and probally other's) extension-point model. All plugins share similar properties (name, id, version etc) and each plugin could in theory satisfy any extension-point. The actual plugin (ie Dll) handling is managed by another library, all I am doing really is managing collections of interfaces for the application. I started by using an enum PluginType to distinguish the different interfaces, but I have quickly realised that using template functions made the code far cleaner and would leave the grunt work up to the compiler, rather than forcing me to use lots of switch {...} statements. The only issue is where I need to specify like functionality for class members - most obvious example is the default plugin which provides a particular interface. A Settings class handles all settings, including the default plugin for an interface. ie Skin newSkin = settings.GetDefault<ISkin>(); How do I store the default ISkin in a container without resorting to some other means of identifying the interface? As I mentioned above, I currently use a std::map<PluginType, IPlugin> Settings::defaults member to achieve this (where IPlugin is an abstract base class which all plugins derive from. I can then dynamic_cast to the desired interface when required, but this really smells of bad design to me and introduces more harm than good I think. would welcome any tips edit: here's an example of the current use of default plugins typedef boost::shared_ptr<ISkin> Skin; typedef boost::shared_ptr<IPlugin> Plugin; enum PluginType { skin, ..., ... } class Settings { public: void SetDefault(const PluginType type, boost::shared_ptr<IPlugin> plugin) { m_default[type] = plugin; } boost::shared_ptr<IPlugin> GetDefault(const PluginType type) { return m_default[type]; } private: std::map<PluginType, boost::shared_ptr<IPlugin> m_default; }; SkinManager::Initialize() { Plugin thedefault = g_settings.GetDefault(skinplugin); Skin defaultskin = boost::dynamic_pointer_cast<ISkin>(theskin); defaultskin->Initialize(); } I would much rather call the getdefault as the following, with automatic casting to the derived class. However I need to specialize for every class type. template<> Skin Settings::GetDefault<ISkin>() { return boost::dynamic_pointer_cast<ISkin>(m_default(skin)); }

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  • Is throwing an exception a healthy way to exit?

    - by ramaseshan
    I have a setup that looks like this. class Checker { // member data Results m_results; // see below public: bool Check(); private: bool Check1(); bool Check2(); // .. so on }; Checker is a class that performs lengthy check computations for engineering analysis. Each type of check has a resultant double that the checker stores. (see below) bool Checker::Check() { // initilisations etc. Check1(); Check2(); // ... so on } A typical Check function would look like this: bool Checker::Check1() { double result; // lots of code m_results.SetCheck1Result(result); } And the results class looks something like this: class Results { double m_check1Result; double m_check2Result; // ... public: void SetCheck1Result(double d); double GetOverallResult() { return max(m_check1Result, m_check2Result, ...); } }; Note: all code is oversimplified. The Checker and Result classes were initially written to perform all checks and return an overall double result. There is now a new requirement where I only need to know if any of the results exceeds 1. If it does, subsequent checks need not be carried out(it's an optimisation). To achieve this, I could either: Modify every CheckN function to keep check for result and return. The parent Check function would keep checking m_results. OR In the Results::SetCheckNResults(), throw an exception if the value exceeds 1 and catch it at the end of Checker::Check(). The first is tedious, error prone and sub-optimal because every CheckN function further branches out into sub-checks etc. The second is non-intrusive and quick. One disadvantage is I can think of is that the Checker code may not necessarily be exception-safe(although there is no other exception being thrown anywhere else). Is there anything else that's obvious that I'm overlooking? What about the cost of throwing exceptions and stack unwinding? Is there a better 3rd option?

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