Search Results

Search found 23271 results on 931 pages for 'static classes'.

facebook twitter digg google delicious technorati stumbleupon myspace wordpress linkedin gmail igoogle windows live tumblr viadeo yahoo buzz yahoo mail yahoo bookmarks favorites email print

Page 405/931 | < Previous Page | 401 402 403 404 405 406 407 408 409 410 411 412  | Next Page >

  • Call from a singleton class to a function which in turn calls that class's method

    - by dare2be
    Hello, I am still looking for a way to phrase it properly (I'm not a native speaker...). So I have this class SQL which implements the singleton pattern (for obvious reasons) and I also have this function, checkUsr(), which queries the database using one of SQL's methods. Everything works fine as long as I don't call checkUsr() from within the SQL class. When I do so, the scripts just exits and a blank page is displayed - no errors are returned, no exception is thrown... What's happening? And how do I work around this problem? EDIT: class SQL { public static function singleton() { static $instance; if(!isset($instance)) $instance = new SQL; return $instance; } public function tryLoginAuthor( $login, $sha1 ) { (...) } } function checkUsr() { if (!isset($_SESSION['login']) || !isset($_SESSION['sha1'])) throw new Exception('Not logged in', 1); $SQL = SQL::singleton(); $res = $SQL->tryLoginAuthor($_SESSION['login'], $_SESSION['sha1']); if (!isset($res[0])) throw new Exception('Not logged in', 1); }

    Read the article

  • Controlling race condition at startup.

    - by Will Hartung
    I have some code that I want to have some one time initialisation performed. But this code doesn't have a definite lifecycle, so my logic can be potentially invoked by multiple threads before my initialisation is done. So, I want to basically ensure that my logic code "waits" until initialisation is done. This is my first cut. public class MyClass { private static final AtomicBoolean initialised = new AtomicBoolean(false); public void initialise() { synchronized(initialised) { initStuff(); initialised.getAndSet(true); initialised.notifyAll(); } } public void doStuff() { synchronized(initialised) { if (!initialised.get()) { try { initialised.wait(); } catch (InterruptedException ex) { throw new RuntimeException("Uh oh!", ex); } } } doOtherStuff(); } } I basically want to make sure this is going to do what I think it's going to do -- block doStuff until the initialised is true, and that I'm not missing a race condition where doStuff might get stuck on a Object.wait() that will never arrive. Edit: I have no control over the threads. And I want to be able to control when all of the initialisation is done, which is why doStuff() can't call initialise(). I used an AtomicBoolean as it was a combination of a value holder, and an object I could synchronize. I could have also simply had a "public static final Object lock = new Object();" and a simple boolean flag. AtomicBoolean conveniently gave me both. A Boolean can not be modified. The CountDownLatch is exactly what I was looking for. I also considered using a Sempahore with 0 permits. But the CountDownLatch is perfect for just this task.

    Read the article

  • Grails problem with nullable contraint in domain class

    - by xain
    Hi, I'm having the following problem with grails' 1.2.1 domain classes: When I set a constraint attr(nullable:true) and attr is int or bool, this condition isn't reflected in the db (postgresql 8.4). However, if attr is a String, the DB is consistent with the situation. Any hints ? Thanks

    Read the article

  • When should I implement IDisposeable?

    - by Bobby
    What is the best practice for when to implement IDisposeable? Is the best rule of thumb to implement it if you have one managed object in the class, or does it depend if the object was created in the class or just passed in? Should I also do it for classes with no managed objects at all?

    Read the article

  • Java: most efficient way to defensively copy an int[]?

    - by Jason S
    I have an interface DataSeries with a method int[] getRawData(); For various reasons (primarily because I'm using this with MATLAB, and MATLAB handles int[] well) I need to return an array rather than a List. I don't want my implementing classes to return the int[] array because it is mutable. What is the most efficient way to copy an int[] array (sizes in the 1000-1000000 length range) ? Is it clone()?

    Read the article

  • .NET Results Class

    - by pm_2
    I have a C# function that does some processing and needs to return figures about what it has processed, success, failure, etc. Can anyone tell me if there are any standard framework classes that will handle this (for example, number of records processed, number successful, failed, etc) ? Alternatively, can anyone say how they usually handle this? Is the best way to create a class, or to use out parameters?

    Read the article

  • Multiple locking task (threading)

    - by Archeg
    I need to implement the class that should perform locking mechanism in our framework. We have several threads and they are numbered 0,1,2,3.... We have a static class called ResourceHandler, that should lock these threads on given objects. The requirement is that n Lock() invokes should be realeased by m Release() invokes, where n = [0..] and m = [0..]. So no matter how many locks was performed on single object, only one Release call is enough to unlock all. Even further if o object is not locked, Release call should perform nothing. Also we need to know what objects are locked on what threads. I have this implementation: public class ResourceHandler { private readonly Dictionary<int, List<object>> _locks = new Dictionary<int, List<object>>(); public static ResourceHandler Instance {/* Singleton */} public virtual void Lock(int threadNumber, object obj) { Monitor.Enter(obj); if (!_locks.ContainsKey(threadNumber)) {_locks.Add(new List<object>());} _locks[threadNumber].Add(obj); } public virtual void Release(int threadNumber, object obj) { // Check whether we have threadN in _lock and skip if not var count = _locks[threadNumber].Count(x => x == obj); _locks[threadNumber].RemoveAll(x => x == obj); for (int i=0; i<count; i++) { Monitor.Exit(obj); } } // ..... } Actually what I am worried here about is thread-safety. I'm actually not sure, is it thread-safe or not, and it's a real pain to fix that. Am I doing the task correctly and how can I ensure that this is thread-safe?

    Read the article

  • How to reduce the Bandwidth Consumption in flex app,while its launching application ?

    - by Thirst for Excellence
    Recently i designed one Abode air Chat application, which gets the chat messages from admin-Application(we bApplication), band width consumption is too high while each client launching air application to pull the data from database to my-amf endpoint. in this am using blazeds,Jetty server,simple java classes(not servlets) calling with remote object, Please any one suggest me few techiniques to 1)reduce the bandwidh consumption while sending message to each client from admin 2)minimize the time to pull the data from database while client launching application. Regards, Thirst for Excellence

    Read the article

  • C++ shared objects

    - by Klaus
    Hello, I have got four classes A, B, C and D. Class A has a member b of class B. Class B has a member c of class C. A has a member D* dpointer; This hierarchy has to be preserved (in fact this is a GUI with app, window, panel as A, B and C). Now B and C must use a method from *dpointer. Is there something more elegant than giving dpointer as a member of B and C ? Is it bad ?

    Read the article

  • meaning of import statement in java file

    - by Rozer
    Can any one clear me exactly what happend when we do import statement in java files. does it inscrease the size of file if we add more and more java classes. why we dont use classloader for the same and what are the restrictin for importing.

    Read the article

  • What will be the OOP approach? (or YOUR approach?)

    - by hsmit
    I'm having difficulties with some general OOP & Java approach. There are various ways to let classes/objects communicate with each other. To give a simple example: I need object A to perform action X. Object A needs P, Q and R to perform this action X. Will then Object A retrieve P, Q and R by itself (within action X), or must these values be parameters for action X?

    Read the article

  • Can this extension method be improve

    - by Newbie
    I have the following extension method public static class ListExtensions { public static IEnumerable<T> Search<T>(this ICollection<T> collection, string stringToSearch) { foreach (T t in collection) { Type k = t.GetType(); PropertyInfo pi = k.GetProperty("Name"); if (pi.GetValue(t, null).Equals(stringToSearch)) { yield return t; } } } } What it does is by using reflection, it finds the name property and then filteres the record from the collection based on the matching string. This method is being called as List<FactorClass> listFC = new List<FactorClass>(); listFC.Add(new FactorClass { Name = "BKP", FactorValue="Book to price",IsGlobal =false }); listFC.Add(new FactorClass { Name = "YLD", FactorValue = "Dividend yield", IsGlobal = false }); listFC.Add(new FactorClass { Name = "EPM", FactorValue = "emp", IsGlobal = false }); listFC.Add(new FactorClass { Name = "SE", FactorValue = "something else", IsGlobal = false }); List<FactorClass> listFC1 = listFC.Search("BKP").ToList(); It is working fine. But a closer look into the extension method will reveal that Type k = t.GetType(); PropertyInfo pi = k.GetProperty("Name"); is actually inside a foreach loop which is actually not needed. I think we can take it outside the loop. But how? PLease help. (C#3.0)

    Read the article

  • In .NET Xml Serialization, is it possible to serialize a class with an enum property with different

    - by Lasse V. Karlsen
    I have a class, containing a list property, where the list contains objects that has an enum property. When I serialize this, it looks like this: <?xml version="1.0" encoding="ibm850"?> <test> <events> <test-event type="changing" /> <test-event type="changed" /> </events> </test> Is it possible, through attributes, or similar, to get the Xml to look like this? <?xml version="1.0" encoding="ibm850"?> <test> <events> <changing /> <changed /> </events> </test> Basically, use the property value of the enum as a way to determine the tag-name? Is using a class hierarchy (ie. creating subclasses instead of using the property value) the only way? Edit: After testing, it seems even a class-hierarchy won't actually work. If there is a way to structure the classes to get the output I want, even with sub-classes, that is also an acceptable answer. Here's a sample program that will output the above Xml (remember to hit Ctrl+F5 to run in Visual Studio, otherwise the program window will close immediately): using System; using System.Collections.Generic; using System.Xml.Serialization; namespace ConsoleApplication18 { public enum TestEventTypes { [XmlEnum("changing")] Changing, [XmlEnum("changed")] Changed } [XmlType("test-event")] public class TestEvent { [XmlAttribute("type")] public TestEventTypes Type { get; set; } } [XmlType("test")] public class Test { private List<TestEvent> _Events = new List<TestEvent>(); [XmlArray("events")] public List<TestEvent> Events { get { return _Events; } } } class Program { static void Main(string[] args) { Test test = new Test(); test.Events.Add(new TestEvent { Type = TestEventTypes.Changing }); test.Events.Add(new TestEvent { Type = TestEventTypes.Changed }); XmlSerializer serializer = new XmlSerializer(typeof(Test)); XmlSerializerNamespaces ns = new XmlSerializerNamespaces(); ns.Add("", ""); serializer.Serialize(Console.Out, test, ns); } } }

    Read the article

  • Dispose, when is it called?

    - by Snake
    Consider the following code: namespace DisposeTest { using System; class Program { static void Main(string[] args) { Console.WriteLine("Calling Test"); Test(); Console.WriteLine("Call to Test done"); } static void Test() { DisposeImplementation di = new DisposeImplementation(); } } internal class DisposeImplementation : IDisposable { ~DisposeImplementation() { Console.WriteLine("~ in DisposeImplementation instance called"); } public void Dispose() { Console.WriteLine("Dispose in DisposeImplementation instance called"); } } } The Dispose just never get's called, even if I put a wait loop after the Test(); invocation. So that quite sucks. I want to write a class that is straightforward and very easy to use, to make sure that every possible resource is cleaned up. I don't want to put that responsibilty to the user of my class. Possible solution: use using, or call Dispose myself(basicly the same). Can I force the user to use a using? Or can I force the dispose to be called? Calling GC.Collect(); after Test(); doesn't work either. Putting di to null doesn't invoke Dispose either. The Deconstructor DOES work, so the object get's deconstructed when it exits Test()

    Read the article

  • Implementing prototypes OR instantiating class objects

    - by intuited
    I'm wondering how to implement prototypal inheritance in Python. It seems like the way to do this would be to either use a metaclass to cause instantiations to actually be classes, rather than objects, or use some magical powers to transform an existing object into a class. The second method would seem to be more flexible, in that it could be applied to existing objects of varied types, while the first would likely be more convenient for typical use cases. Insights on the practicality of these two approaches, as well as alternative suggestions, are hereby requested.

    Read the article

  • out of memory error , my app's fault?

    - by arnold
    hello all, i have a aplication on the android market , in wich exceptions and errors are catched and sent to me by acra. But i receive quite a lot out of memory errors.. In different kind of classes...some my app, some general java.. Does this always mean there is a problem in my app, or can it also be the phone ran out of memory due to a other process? Will users also get a fc dialog ? thnks

    Read the article

  • Calling an Overridden Method from a Parent-Class Constructor

    - by Vaibhav Bajpai
    I tried calling an overridden method from a constructor of a parent class and noticed different behavior across languages. C++ - echoes A.foo() class A{ public: A(){foo();} virtual void foo(){cout<<"A.foo()";} }; class B : public A{ public: B(){} void foo(){cout<<"B.foo()";} }; int main(){ B *b = new B(); } Java - echoes B.foo() class A{ public A(){foo();} public void foo(){System.out.println("A.foo()");} } class B extends A{ public void foo(){System.out.println("B.foo()");} } class Demo{ public static void main(String args[]){ B b = new B(); } } C# - echoes B.foo() class A{ public A(){foo();} public virtual void foo(){Console.WriteLine("A.foo()");} } class B : A{ public override void foo(){Console.WriteLine("B.foo()");} } class MainClass { public static void Main (string[] args) { B b = new B(); } } I realize that in C++ objects are created from top-most parent going down the hierarchy, so when the constructor calls the overridden method, B does not even exist, so it calls the A' version of the method. However, I am not sure why I am getting different behavior in Java and C#.

    Read the article

  • nsmutablearray and saving to file

    - by Amir
    hello all, I have class named Shop that contain data members (NSString , NSInteger and nsmutablearray that contain another class(that have also NSString and NSInteger) Now if i use nsmutablearray to hold alist of Shops what is the best way to save the list to file and load it later? again the class Shop contain data memeber that is another class both of the classes have NSString and NSinteger (maybe also NSdata and NSdate) i heard somthing about archiver?? thanks.

    Read the article

  • multiplying all elements in an array by an outside number?

    - by prodo
    I need to multiple all the values in an array by 3000 which in turn would create a new array that I will use to subtract from another array. I've tried to create a separate method that would do that for me but all I got back in the multiplied array was a bunch of numbers and symbols strangely? here is the code that I wrote public static void main(String[] args) { int numberOfTaxpayers = Integer.parseInt(JOptionPane.showInputDialog("Enter how many users you would like to calculate taxes for: "); int[] usernumChild = new int[numberOfTaxPayers]; for (int i = 0; i < usernumChild.length; i++) { usernumChild[i] = Integer.parseInt(JOptionPane.showInputDialog("Enter number of children for user "+ (i+1) +": ")); }//this for loop finds out the number of children per user so we can later multiply each input by 3000 to create an array that determine dependency exemption for each user int[] depndExemp = multiply(usernumChild, 3000);//this was the calling of the multiply method... somewhere here is the error!! }//end main method public static int[] multiply(int[] children, int number) { int array[] = new int[children.length]; for( int i = 0; i < children.length; i++) { children[i] = children[i] * number; }//end for return array; }//this is the method that I was shown in a previous post on how to create return an array in this the dependency exemption array but when I tested this by printing out the dependency array all I received were a jumble of wrong numbers.

    Read the article

facebook twitter digg google delicious technorati stumbleupon myspace wordpress linkedin gmail igoogle windows live tumblr viadeo yahoo buzz yahoo mail yahoo bookmarks favorites email print

< Previous Page | 401 402 403 404 405 406 407 408 409 410 411 412  | Next Page >