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Search found 327 results on 14 pages for 'instantiation'.

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  • Guice creates Swing components outside of UI thread problem?

    - by Boris Pavlovic
    I'm working on Java Swing application with Google Guice as an IOC container. Things are working pretty well. There are some UI problems. When a standard L&F is replaced with Pushing pixels Substance L&F application is not running due to Guice's Swing components creation outside of UI thread. Is there a way to tell Guice to create Swing components in the UI thread? Maybe I should create custom providers which will return Swing components after SwingUtilities.invokeAndWait(Runnable) creates them. I don't like the idea of running the whole application in UI thread, but maybe it's just a perfect solution.

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  • Simple vector program error

    - by Codeguru
    Hi iam new to c++ and iam trying out this vector program and i am getting the following error: error: conversion from test*' to non-scalar typetest' requested| Here is the code include include include include using namespace std; class test{ string s; vector <string> v; public: void read(){ ifstream in ("c://test.txt"); while(getline(in,s)) { v.push_back(s); } for(int i=0;i<v.size();i++) { cout<<v[i]<<"\n"; } } }; int main() { cout<<"Opening the file to read and displaying on the screen"< }

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  • OOP - Handling Automated Instances of a Class - PHP

    - by dscher
    This is a topic that, as a beginner to PHP and programming, sort of perplexes me. I'm building a stockmarket website and want users to add their own stocks. I can clearly see the benefit of having each stock be a class instance with all the methods of a class. What I am stumped on is the best way to give that instance a name when I instantiate it. If I have: class Stock() { ....doing stuff..... } what is the best way to give my instances of it a name. Obviously I can write: $newStock = new Stock(); $newStock.getPrice(); or whatever, but if a user adds a stock via the app, where can the name of that instance come from? I guess that there is little harm in always creating a new child with $newStock = new Stock() and then storing that to the DB which leads me to my next question! What would be the best way to retrieve 20 user stocks(for example) into instances of class Stock()? Do I need to instantiate 20 new instances of class Stock() every time the user logs in or is there something I'm missing? I hope someone answers this and more important hope a bunch of people answer this and it somehow helps someone else who is having a hard time wrapping their head around what probably leads to a really elegant solution. Thanks guys!

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  • Is there anything wrong with my Factory class?

    - by Alex
    class PieceFactory { @SuppressWarnings("rawtypes") public Piece createPiece(String pieceType) throws Throwable{ Class pieceClass = Class.forName(pieceType); Piece piece = (Piece) pieceClass.newInstance(); return piece; } } I'm not all used to handling exceptions yet therefore I'm just throwing them, but everywhere I use a method that uses this factory it tells me I have to throw exceptions like throwable. For example, in one of my classes I have a method that instantiates a lot of objects using the method that uses the factory. I can use the method in that class by just throwing the exception, however it won't work if I try to pass a reference to that class to another class and then use the method from there. Then it forces me to try catch the exception. I probably don't need a factory but it seemed interesting and I'd like to try to use patterns. The reason I created the factory was that I have 6 subclasses of Piece and I wan't to use a method to instantiate them by passing the type of subclass I want as an argument to the method.

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  • awakeFromNib and loadView execute for different instances

    - by Kamchatka
    Hi, I'm trying to understand why: NSLog(@"self = %p", self); in awakeFromNib prints a different value than the same NSLog in viewDidLoad? This isn't a huge problem because I don't need the awakeFromNib but I would like to understand how it works. The code that creates the controller is the following: MyViewController *myViewController = [[MyViewController alloc] initWithNibName:@"MyViewController" bundle:nil]; myViewController.image = tmpImage; [self.navigationController pushViewController:myViewController animated:YES]; [myViewController release]; Thanks for any advices!

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  • Constructor within a constructor

    - by Chiramisu
    Is this a bad idea? Does calling a generic private constructor within a public constructor create multiple instances, or is this a valid way of initializing class variables? Private Class MyClass Dim _msg As String Sub New(ByVal name As String) Me.New() 'Do stuff End Sub Sub New(ByVal name As String, ByVal age As Integer) Me.New() 'Do stuff End Sub Private Sub New() 'Initializer constructor Me._msg = "Hello StackOverflow" 'Initialize other variables End Sub End Class

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  • How to set default values to the properties of dynamically loaded types at runtime for XML serializa

    - by Erkan Y.
    I need to serialize dynamically loaded types' classes using XMLSerializer. When using XML serializer non initialized values are not being serialized. I dont have control over the assemblies I am working with so can not use XML attributes for specifying default values on properties. So I think I need to set all properties and sub properties to their default values recursively and then serialize. ( Please let me know if there is any better way ) Followed this : Activator.CreateInstance(propType); but above line complains about not having a parameterless constructor for some types. Tried this : subObject = FormatterServices.GetUninitializedObject(propType); but this one gives an error "value was invalid" with no inner exception. Please let me know if you need any further information.

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  • Is it possible to create an enum whose object can't be created but can be used for readonly purpose

    - by Shantanu Gupta
    I created an enum where I stored some table names. I want it to be used to get the name of the table like ds.Tables[BGuestInfo.TableName.L_GUEST_TYPE.ToString()]. public enum TableName : byte { L_GUEST_TYPE = 0 ,L_AGE_GROUP = 1 ,M_COMPANY = 2 ,L_COUNTRY = 3 ,L_EYE_COLOR = 4 ,L_GENDER = 5 ,L_HAIR_COLOR = 6 ,L_STATE_PROVINCE = 7 ,L_STATUS = 8 ,L_TITLE = 9 ,M_TOWER = 10 ,L_CITY = 11 ,L_REGISTER_TYPE = 12 } This is my enum. Now I have not created any object of this enum so that no one can use it for other than read only purpose. For this enum to be accessible in outer classes as well I have to make it public which means some outer class can create its object as well. So what can i do so as to restrict its object creation.

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  • What happens when I instantiate class in Python?

    - by Konstantin
    Could you clarify some ideas behind Python classes and class instances? Consider this: class A(): name = 'A' a = A() a.name = 'B' # point 1 (instance of class A is used here) print a.name print A.name prints: B A if instead in point 1 I use class name, output is different: A.name = 'B' # point 1 (updated, class A itself is used here) prints: B B Even if classes in Python were some kind of prototype for class instances, I'd expect already created instances to remain intact, i.e. output like this: A B Can you explain what is actually going on?

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  • .NET object creation and generations

    - by nimoraca
    Is there a way to tell the .NET to allocate a new object in generation 2 heap. I have a problem where I need to allocate approximately 200 MB of objects, do something with them, and throw them away. What happens here is that all the data gets copied two times (from gen0 to gen1 and then from gen1 to gen2).

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  • How can a class's memory-allocated address be determined from within the contructor?

    - by Jim Fell
    Is it possible to get the memory-allocated address of a newly instantiated class from within that class's constructor during execution of said constructor? I am developing a linked list wherein multiple classes have multiple pointers to like classes. Each time a new class instantiates, it needs to check its parent's list to make sure it is included. If I try to do something like this: MyClass() // contructor { extern MyClass * pParent; for ( int i = 0; i < max; i++ ) { pParent->rels[i] == &MyClass; // error } } I get this error: error C2275: 'namespace::MyClass' : illegal use of this type as an expression Any thoughts or suggestions would be appreciated. Thanks.

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  • Segmentation fault on instationation of more than 1 object

    - by ECE
    I have a class called "Vertex.hpp" which is as follows: #include <iostream> #include "Edge.hpp" #include <vector> using namespace std; /** A class, instances of which are nodes in an HCTree. */ class Vertex { public: Vertex(char * str){ *name=*str; } vector<Vertex*> adjecency_list; vector<Edge*> edge_weights; char *name; }; #endif When I instantiate an object of type Vector as follows: Vertex *first_read; Vertex *second_read; in.getline(input,256); str=strtok(input," "); first_read->name=str; str=strtok(NULL, " "); second_read->name=str; A segmentation fault occurs when more than 1 object of type Vector is instantiated. Why would this occur if more than 1 object is instantiated, and how can i allow multiple objects to be instantiated?

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  • Problems with instantiating in JAVA

    - by PUPIALEX
    When running, below programme cannot reach the end of the main function.. I am new to JAVA, and cannot find its defections.. I need your help. Thanks. import java.util.*; class Schedule { public String day; private int startTime, endTime; public Schedule(String input_day, int input_start, int input_end) { day = input_day; startTime = input_start; endTime = input_end; } /* clashWith: to check whether this schedule clash with a Schedule called otherSchedule * PRE-Condition : input must be of Schedule type * POST-Condition : return true if two Schedule clash, return false if not. */ public boolean clashWith(Schedule otherSchedule) { if(this.day != otherSchedule.day || this.endTime <= otherSchedule.startTime || this.startTime >= otherSchedule.endTime) return false; return true; } } class Module { String code; Schedule lecture, tutorial, lab; public Module(String input_code, Schedule input_lecture, Schedule input_tutorial, Schedule input_lab) { code = input_code; lecture = input_lecture; tutorial = input_tutorial; lab = input_lab; } /* count: to count number of classes(lecture, tutorial, and lab of only this Module) on day. * For example: when day = "Monday", lecture is on Monday, tutorial is on Monday * but lab is on Tuesday, then return 2. (lecture and tutorial are on Monday). * PRE-Condition : * POST-Condition : */ public int count(String day) { int num = 0; if(lecture.day == day) num++; if(tutorial.day == day) num++; if(lab.day == day) num++; return num; } /* clashWith: to check whether this module clash with a Module called otherModule * PRE-Condition : * POST-Condition : */ public boolean clashWith(Module otherModule) { if(lecture.clashWith(otherModule.lecture) || lecture.clashWith(otherModule.tutorial) || lecture.clashWith(otherModule.lab) ) return true; if(tutorial.clashWith(otherModule.lecture) || tutorial.clashWith(otherModule.tutorial) || tutorial.clashWith(otherModule.lab)) return true; if(lab.clashWith(otherModule.lecture) || lab.clashWith(otherModule.tutorial) || lab.clashWith(otherModule.lab)) return true; return false; } } class Timetable { Vector<Module> listOfModule; public Timetable() { } /* checkClash: to check whether otherModule clash with one of * the modules in our timetable list. * PRE-Condition : * POST-Condition : */ public boolean checkClash(Module otherModule) { for(Module c: listOfModule) if(c.clashWith(otherModule)) return true; return false; } /* add: to add a new module to the timetable list. * PRE-Condition : * POST-Condition : */ public void add(Module module) { listOfModule.add(module); } /* count: to count number of classes on day. * PRE-Condition : * POST-Condition : */ public int count(String day) { int count_day=0; for(Module c: listOfModule) count_day += c.count(day); return count_day; } } public class Main { public static void main(String[] args) { Scanner input = new Scanner(System.in); int num_operation; String code ; Timetable userTimetable = new Timetable(); num_operation = input.nextInt(); for(int i=0;i<num_operation;i++) { if(input.next() == "MODULE") { code = input.next(); String day; int start, end; Schedule getLecSche = new Schedule(input.next(),input.nextInt(),input.nextInt()); Schedule getTutSche = new Schedule(input.next(),input.nextInt(),input.nextInt()); Schedule getLabSche = new Schedule(input.next(),input.nextInt(),input.nextInt()); Module userModule = new Module(code, getLecSche, getTutSche, getLabSche); System.out.println("Reached line 162"); if(!userTimetable.checkClash(userModule)) { userTimetable.add(userModule); System.out.println("Added"); } else System.out.println("Clashed"); } else if(input.next() == "COUNT"){ code = input.next(); System.out.println(userTimetable.count(code)); } } } }

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  • Create a new instance in a static function of an abstract class

    - by arno
    abstract class db_table { static function get_all_rows() { ... while(...) { $rows[] = new self(); ... } return $rows; } } class user extends db_table { } $rows = user::get_all_rows(); I want to create instances of a class from a static method defined in the abstract parent class but PHP tells me "Fatal error: Cannot instantiate abstract class ..." How should I implement it correctly?

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  • Load all tab bar views when application first runs

    - by codenoobie
    Here's the problem. I have a tab bar controller with 4 separate views. When I navigate from the first view to the second view, it takes some time to load up the second view. What I want to do is be able to load and initialize all of my tab bar views during my splash screen. That way, when the user navigates between the tab views, there is no wait time. So the question is... how do I manually initialize my individual tab bar views in my app delegate? And once again, thank you stackoverflow!

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  • Creating an instance within the Class itself

    - by didxga
    What's going on when the assignment statement executed at Line 4, does compiler ignore the new operator and keep the foo variable being null or something else happen to handle this awkward moment? public class Foo { // creating an instance before its constructor has been invoked, suppose the "initializing" // gets printed in constructor as a result of the next line, of course it will not print it private Foo foo = new Foo();//Line 4 public Foo() { System.out.println("initializing"); } }

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  • Is it possible to create an enum whose instance can't be created but can be used for readonly purpos

    - by Shantanu Gupta
    I created an enum where I stored some table names. I want it to be used to get the name of the table like ds.Tables[BGuestInfo.TableName.L_GUEST_TYPE.ToString()]. public class a { public enum TableName : byte { L_GUEST_TYPE = 0 ,L_AGE_GROUP = 1 ,M_COMPANY = 2 ,L_COUNTRY = 3 ,L_EYE_COLOR = 4 ,L_GENDER = 5 ,L_HAIR_COLOR = 6 ,L_STATE_PROVINCE = 7 ,L_STATUS = 8 ,L_TITLE = 9 ,M_TOWER = 10 ,L_CITY = 11 ,L_REGISTER_TYPE = 12 } } class b { a.TableName x; //trying to restrict this ds.Tables[a.TableName.L_GUEST_TYPE] //accessible and can be used like this } This is my enum. Now I have not created any instance of this enum so that no one can use it for other than read only purpose. For this enum to be accessible in outer classes as well I have to make it public which means some outer class can create its object as well. So what can i do so as to restrict its instance creation.

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  • Manipulate method functionality call

    - by danrichardson
    Hello, is it possibly in c# to have some sort of base class functionality which is manipulated slightly based on the class. For instance say i have the following code (which will quite obviously not compile it's meant to only be for demonstrative purposes) class BaseFunctionality { public virtual bool adminCall public static string MethodName(int id, string parameter) { if (adminCall) return dbcall.Execute(); else return dbcall.ExecuteMe(); } } class Admin : BaseFunctionality { override bool adminCall = true; } class Front : BaseFunctionality { override bool adminCall = false; } Now what i would like to be able to do is; string AdminCall = Admin.MethodName(1, "foo"); string FrontCall = Front.MethodName(2, "bar"); Is their any way to do something like this? I'm trying to do everything with static methods so i do not have to instantiate classes all the time, and have nice clean code which is only being manipulated in one place. The idea behind this is so that there is minimal code repeating and makes things easier to expand on, so for instance another class could implement the BaseFunctionality later on. Thanks Dan

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  • Trying to instantiate a class member in C++ with a variable name

    - by MarcZero
    Hello. I am writing a program for class that is asking us to create a class of "book". We are then supposed to create new instantiations of that class upon demand from the user. I am new to C++ so I am attempting to code this out but am running into a problem. The main problem is how do I instantiate a class with a variable if I don't know how many I will have to do ahead of time. The user could ask to add 1 book or 1000. I am looking at this basic code: This is the simple code I started with. I wanted to have an index int keep a number and have the book class I create be called by that int (0, 1, 2, etc...) So I attempted to convert the incoming index int into a string, but I'm kind of stuck from here. void addBook(int index){ string bookName; std::stringstream ss; ss << index; book bookName; cout << "Enter the Books Title: "; cin >> bookName.title; } But obviously this doesn't work as "bookName" is a string to the computer and not the class member I tried to create. All of the tutorials I have seen online and in my text show the classes being instantiated with names in the code, but I just don't know how to make it variable so I can create any amount of "books" that the user might want. Any insight on this would be appreciated. Thank you for your time.

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  • When does a const return type interfere with template instantiation?

    - by Rimo
    From Herb Sutter's GotW #6 Return-by-value should normally be const for non-builtin return types. ... Note: Lakos (pg. 618) argues against returning const value, and notes that it is redundant for builtins anyway (for example, returning "const int"), which he notes may interfere with template instantiation. While Sutter seems to disagree on whether to return a const value or non-const value when returning an object of a non-built type by value with Lakos, he generally agrees that returning a const value of a built-in type (e.g const int) is not a good idea. While I understand why that is useless because the return value cannot be modified as it is an rvalue, I cannot find an example of how that might interfere with template instantiation. Please give me an example of how having a const qualifier for a return type might interfere with template instantiation.

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  • Why instantiation of static nested class object is allowed?

    - by Parag Meshram
    I have started learning Java language for Android Application developement. As per my understanding based on static class, we cannot instantiate object of static class. But why instantiation of static nested class object is allowed in following situaltion? class EnclosingClass { //... class static StaticInnerClass { //... } } Why we can create object of inner class if it is marked as static? EnclosingClass.StaticInnerClass s = new EnclosingClass.StaticInnerClass()

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