Search Results

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

Page 170/931 | < Previous Page | 166 167 168 169 170 171 172 173 174 175 176 177  | Next Page >

• Invoking public method on a class in a different package via reflection

  - by KARASZI István

  I ran into the following problem. I have two different packages in package a I would like to call the implemented method of an interface in a package b but the implementing class has package visibility. So a simplifed code looks like this: package b; public final class Factory { public static B createB() { return new ImplB(); } public interface B { void method(); } static class ImplB implements B { public void method() { System.out.println("Called"); } } } and the Invoker: package a; import java.lang.reflect.Method; import b.Factory; import b.Factory.B; public final class Invoker { private static final Class<?>[] EMPTY_CLASS_ARRAY = new Class<?>[] {}; private static final Object[] EMPTY_OBJECT_ARRAY = new Object[] {}; public static void main(String... args) throws Exception { final B b = Factory.createB(); b.method(); final Method method = b.getClass().getDeclaredMethod("method", EMPTY_CLASS_ARRAY); method.invoke(b, EMPTY_OBJECT_ARRAY); } } When I start the program it prints out Called as expected and throws an Exception because the package visibility prohibits the calling of the discovered method. So my question is any way to solve this problem? Am I missing something in Java documentation or this is simply not possible although simply calling an implemented method is possible without reflection.

  Read the article

• Fill container with template parameters

  - by phlipsy

  I want to fill the template parameters passed to a variadic template into an array with fixed length. For that purpose I wrote the following helper function templates template<typename ForwardIterator, typename T> void fill(ForwardIterator i) { } template<typename ForwardIterator, typename T, T head, T... tail> void fill(ForwardIterator i) { *i = head; fill<ForwardIterator, T, tail...>(++i); } the following class template template<typename T, T... args> struct params_to_array; template<typename T, T last> struct params_to_array<T, last> { static const std::size_t SIZE = 1; typedef std::array<T, SIZE> array_type; static const array_type params; private: void init_params() { array_type result; fill<typename array_type::iterator, T, head, tail...>(result.begin()); return result; } }; template<typename T, T head, T... tail> struct params_to_array<T, head, tail...> { static const std::size_t SIZE = params_to_array<T, tail...>::SIZE + 1; typedef std::array<T, SIZE> array_type; static const array_type params; private: void init_params() { array_type result; fill<typename array_type::iterator, T, last>(result.begin()); return result; } }; and initialized the static constants via template<typename T, T last> const typename param_to_array<T, last>::array_type param_to_array<T, last>::params = param_to_array<T, last>::init_params(); and template<typename T, T head, T... tail> const typename param_to_array<T, head, tail...>::array_type param_to_array<T, head, tail...>::params = param_to_array<T, head, tail...>::init_params(); Now the array param_to_array<int, 1, 3, 4>::params is a std::array<int, 3> and contains the values 1, 3 and 4. I think there must be a simpler way to achieve this behavior. Any suggestions? Edit: As Noah Roberts suggested in his answer I modified my program like the following: I wrote a new struct counting the elements in a parameter list: template<typename T, T... args> struct count; template<typename T, T head, T... tail> struct count<T, head, tail...> { static const std::size_t value = count<T, tail...>::value + 1; }; template<typename T, T last> stuct count<T, last> { static const std::size_t value = 1; }; and wrote the following function template<typename T, T... args> std::array<T, count<T, args...>::value> params_to_array() { std::array<T, count<T, args...>::value> result; fill<typename std::array<T, count<T, args...>::value>::iterator, T, args...>(result.begin()); return result; } Now I get with params_to_array<int, 10, 20, 30>() a std::array<int, 3> with the content 10, 20 and 30. Any further suggestions?

  Read the article

• Need a hand understanding this Java code please :-)

  - by Brian

  Hi all, Just wondering if anyone would be able to take a look at this code for implementing the quicksort algorithm and answer me a few questions, please :-) public class Run { /*************************************************************************** * Quicksort code from Sedgewick 7.1, 7.2. **************************************************************************/ public static void quicksort(double[] a) { //shuffle(a); // to guard against worst-case quicksort(a, 0, a.length - 1, 0); } static void quicksort(final double[] a, final int left, final int right, final int tdepth) { if (right <= left) return; final int i = partition(a, left, right); if ((tdepth < 4) && ((i - left) > 1000)) { final Thread t = new Thread() { public void run() { quicksort(a, left, i - 1, tdepth + 1); } }; t.start(); quicksort(a, i + 1, right, tdepth + 1); try { t.join(); } catch (InterruptedException e) { throw new RuntimeException("Cancelled", e); } } else { quicksort(a, left, i - 1, tdepth); quicksort(a, i + 1, right, tdepth); } } // partition a[left] to a[right], assumes left < right private static int partition(double[] a, int left, int right) { int i = left - 1; int j = right; while (true) { while (less(a[++i], a[right])) // find item on left to swap ; // a[right] acts as sentinel while (less(a[right], a[--j])) // find item on right to swap if (j == left) break; // don't go out-of-bounds if (i >= j) break; // check if pointers cross exch(a, i, j); // swap two elements into place } exch(a, i, right); // swap with partition element return i; } // is x < y ? private static boolean less(double x, double y) { return (x < y); } // exchange a[i] and a[j] private static void exch(double[] a, int i, int j) { double swap = a[i]; a[i] = a[j]; a[j] = swap; } // shuffle the array a[] private static void shuffle(double[] a) { int N = a.length; for (int i = 0; i < N; i++) { int r = i + (int) (Math.random() * (N - i)); // between i and N-1 exch(a, i, r); } } // test client public static void main(String[] args) { int N = 5000000; // Integer.parseInt(args[0]); // generate N random real numbers between 0 and 1 long start = System.currentTimeMillis(); double[] a = new double[N]; for (int i = 0; i < N; i++) a[i] = Math.random(); long stop = System.currentTimeMillis(); double elapsed = (stop - start) / 1000.0; System.out.println("Generating input: " + elapsed + " seconds"); // sort them start = System.currentTimeMillis(); quicksort(a); stop = System.currentTimeMillis(); elapsed = (stop - start) / 1000.0; System.out.println("Quicksort: " + elapsed + " seconds"); } } My questions are: What is the purpose of the variable tdepth? Is this considered a "proper" implementation of a parallel quicksort? I ask becuase it doesn't use implements Runnable or extends Thread... If it doesn't already, is it possible to modify this code to use multiple threads? By passing in the number of threads you want to use as a parameter, for example...? Many thanks, Brian

  Read the article

• Nginx frontend for AppEngine dev server

  - by benasio

  How to configure nginx for load static ? Static should be given only by the nginx server , everything else nginx + dev_appserver and workingon the same host (localhost or localhost: port) Example request html http://localhost -> nginx -> dev_appserver request static files http://localhost -> nginx

  Read the article

• Lock thread using somthing other than a object

  - by Scott Chamberlain

  when using a lock does the thing you are locking on have to be a object. For example is this legal static DateTime NextCleanup = DateTime.Now; const TimeSpan CleanupInterval = new TimeSpan(1, 0, 0); private static void DoCleanup() { lock ((object)NextCleanup) { if (NextCleanup < DateTime.Now) { NextCleanup = DateTime.Now.Add(CleanupInterval); System.Threading.ThreadPool.QueueUserWorkItem(new System.Threading.WaitCallback(cleanupThread)); } } return; } EDIT-- From reading SLaks' responce I know the above code would be not valid but would this be? static MyClass myClass = new MyClass(); private static void DoCleanup() { lock (myClass) { // } return; }

  Read the article

• 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); } } } }

  Read the article

• Problem invoking C DLL in C#

  - by CristiC

  I'm currently trying to invoke a method made in C from C# C code looks like this: extern "C" int addSum(int a, int b) { return a*b; } extern "C" int getCount() { return 12; } and C# code looks like this: [DllImport("mydll.dll", SetLastError=true)] private static extern int addSum(IntPtr a, IntPtr b); [DllImport("mydll.dll", SetLastError = true)] private static extern int getCount(); public static int mySum(int a, int b) { return suma(a, b); } public static int getMyCount() { return getCount(); } The code returns the right values but i'm getting the following error: addSum' has unbalanced the stack. This is likely because the managed PInvoke signature does not match the unmanaged target signature. Check that the calling convention and parameters of the PInvoke signature match the target unmanaged signature. Any sugestion regarding this issue ? Thanks

  Read the article

• In Grails, How can I create a domain model to link two of another model?

  - by gerges

  Hey all, I'm currently trying to create a Friendship domain object to link two User objects (with a bit of additional data: createDate, confirmedStatus). My domain model looks as follows class Friendship { User userOne User userTwo Boolean confirmed Date createDate Date lastModifiedDate static belongsTo = [userOne:User , userTwo:User] static constraints = { userOne() userTwo() confirmed() createDate() lastModifiedDate() } } I've also added the following entries to the user class static hasMany = [ friendships:Friendship ] static mappedBy = [ friendships:'userOne' , friendships:'userTwo' ] When I do this, the result is a new friendship created (and viewable through the controller) with both users listed in their respective places. When I view the details of userOne, I see the friedship listed. When I view the details of userTwo, no friendship is listed. This is not the behavior I expected. What am I doing incorrectly? Why can't I see the friendship listed under both users?

  Read the article

• Why `is_base_of` works with private inheritance?

  - by Alexey Malistov

  Why the following code works? typedef char (&yes)[1]; typedef char (&no)[2]; template <typename B, typename D> struct Host { operator B*() const; operator D*(); }; template <typename B, typename D> struct is_base_of { template <typename T> static yes check(D*, T); static no check(B*, int); static const bool value = sizeof(check(Host<B,D>(), int())) == sizeof(yes); }; //Test sample class B {}; class D : private B {}; //Exspression is true. int test[is_base_of<B,D>::value && !is_base_of<D,B>::value]; Note that B is private base. Note that operator B*() is const. How does this work? Why this works? Why static yes check(D*, T); is better than static yes check(B*, int); ?

  Read the article

• What alternatives do I have for source control and does GIT does that?

  - by RubberDuck

  I work as a freelancer programmer for some clients and also create apps for myself. When I work for myself, obviously I work alone. I generally don't work in a linear way. My big problems today are: I have a lot of apps that use the same classes I have developed; In the past, I put all these common classes on a directory outside all projects and included them on my apps using absolute paths, but this method sucks because by accident (if you forget) you may change a path or the disk and all projects are broken. Then I decided to copy those classes to my projects every time. Because the majority of these classes do not change frequently, I am relatively ok, but when they change, I am in hell; When I change one of these classes I have to propagate the changes to all other apps using copies of them. I have also tried to create frameworks but thanks to Apple, I cannot create frameworks for iOS and have to create libraries and bundles and create a nightmare of paths from one to the other and to the project to make that sh!t works. So, I am done with frameworks/libraries on Xcode until Xcode is a decent IDE. So, I see I need something better to manage my source code. What I need is this (I never used GIT on Xcode. I have read Apple docs but I still have these points): does git locally on Xcode allows me to deal with assets or just code? Can I have the equivalent of a "framework" (code + assets) managed by git locally? Can an entire xcodeproj be managed as a unity? I mean, Suppose I have a xcodeproj created and want GIT to manage it. How do I enable git on a project that was created without it and start designating files for management. (I have enabled git on Xcode's preferences, but all source control menu is grayed out). Is git the best option? Do I have another? Remember that my main condition is that the files should stay on the local computer. Please save me (I am a bit dramatic today). Thanks.

  Read the article

• to write log files in two different files

  - by Sun

  my application run on customized client framework,the client framework used log4net to log their own log files. we are(our application) has to use the same log4net to log our log files in our own path(say our customized path). currently the our log files are created but log are not writing in that file.it is writting in the client framework log file. searched lot of sites the link http://stackoverflow.com/questions/308436/log4net-programmatcially-specify-multiple-loggers-with-multiple-file-appenders helped me to configure the log4net config programatically, still im log statemets are not written in my log file.the code used as below public class TraceLog { private string message = string.Empty; private static ILog ILogger = null; private static TraceLog instance = new TraceLog(); private TraceLog() { SetLevel("Log4net.MainForm", "ALL"); AddAppender("Log4net.MainForm", CreateFileAppender("FileAppender", "C:\\mylog.log")); } public static TraceLog Instance { get { return instance; } } public void Debug(string logMessage) { message = PrepareLog(logMessage); ILogger.Debug(message); } protected string PrepareLog(string logMessage) { string message = GetFileMethodLineNumberInfo(); message += logMessage; return message; } protected string GetFileMethodLineNumberInfo() { StackTrace stackTrace = new StackTrace(true); // The position 3 is relative to the index of the specified method StackFrame stackFrame = stackTrace.GetFrame(3); return (stackFrame.GetMethod().DeclaringType.Name + "/" + stackFrame.GetMethod().Name + "/" + stackFrame.GetFileLineNumber() + ":"); } private static void SetLevel(string loggerName, string levelName) { ILogger = LogManager.GetLogger(loggerName); log4net.Repository.Hierarchy.Logger l = (log4net.Repository.Hierarchy.Logger)ILogger.Logger; l.Level = l.Hierarchy.LevelMap[levelName]; } private static void AddAppender(string loggerName, IAppender appender) { ILogger = LogManager.GetLogger(loggerName); log4net.Repository.Hierarchy.Logger l = (log4net.Repository.Hierarchy.Logger)ILogger.Logger; l.AddAppender(appender); } private static IAppender CreateFileAppender(string name, string fileName) { FileAppender appender = new FileAppender(); appender.Name = name; appender.File = fileName; appender.AppendToFile = true; //PatternLayout layout = new PatternLayout(); //layout.ConversionPattern = "%d [%t] %-5p %c [%x] - %m%n"; //layout.ActivateOptions(); //appender.Layout = layout; appender.ActivateOptions(); return appender; } } } anyone pls help how to solve this

  Read the article

• efficient thread-safe singleton in C++

  - by user168715

  The usual pattern for a singleton class is something like static Foo &getInst() { static Foo *inst = NULL; if(inst == NULL) inst = new Foo(...); return *inst; } However, it's my understanding that this solution is not thread-safe, since 1) Foo's constructor might be called more than once (which may or may not matter) and 2) inst may not be fully constructed before it is returned to a different thread. One solution is to wrap a mutex around the whole method, but then I'm paying for synchronization overhead long after I actually need it. An alternative is something like static Foo &getInst() { static Foo *inst = NULL; if(inst == NULL) { pthread_mutex_lock(&mutex); if(inst == NULL) inst = new Foo(...); pthread_mutex_unlock(&mutex); } return *inst; } Is this the right way to do it, or are there any pitfalls I should be aware of? For instance, are there any static initialization order problems that might occur, i.e. is inst always guaranteed to be NULL the first time getInst is called?

  Read the article

• Playing craps, asking and printing

  - by Angelo Mejia

  How do I ask the amount of games of craps someone wants to play and print the number of wins as a result of n number of games? Also How do I make a table in the main method using the previous methods I have? A table like this but shows the results: Percent Wins Games Experiment Number 1 2 3 4 5 6 7 8 9 10 100 1000 10000 100000 1000000 public class CrapsAnalysis { public static int rollDie( int n) { return (int)(Math.random()*n) + 1 ; } public static int rollDice( ) { int die1 ; int die2 ; die1 = rollDie(6) ; die2 = rollDie(6) ; return die1 + die2 ; } public static boolean playOneGame( ) { int newDice ; //repeated dice rolls int roll ; //first roll of the dice int playerPoint = 0 ; //player point if no win or loss on first roll newDice = rollDice() ; roll = rollDice() ; if (roll == 7 || roll == 11) return true; else if (roll == 2 || roll == 3 || roll == 12) return false; else { playerPoint = roll; newDice = rollDice(); do { newDice = rollDice(); } while (newDice != playerPoint || newDice != 7) ; if (newDice == 7) return false; else return true; } } public static int playGames ( int n ) { int numWon = 0; for (int i = 1; i <= n; i++) if(playOneGame()) numWon++; return numWon; } public static void main(String[] args) { //Don't know how to ask and print out the results of the number of wins depending on the n number of games played } }

  Read the article

• What is the simplest way to map a folder on the file system to a url in Tomcat?

  - by Simon

  Here's my problem... I have a small prototype app (happens to be in Grails hosted on AWS) and I want to add the ability of the user to upload a few (max 10) images. I want to persist these images on disk on the server machine, in a folder location which is outside my WAR. I realise that there is probably a super-scalable solution involving more web servers and optimised static asset serving, but for the approximately 100 users I am likely to get, it's really not worth the effort and cost. So, what is the simplest way I can have a virtual folder from my url map to a physical folder on disk? I sort of want... http://myapp.com/static to map to a folder which I can configure e.g. /var/www/static so I can then have in my code... <img src="/static/user1/picture.jpg"/> I don't particularly mind whether the resulting physical folders are directly browsable. Security will eventually be an issue, but it isn't at the start. So, what are my options? I have looked at virtual hosts on the apache site, but it feels more complicated than I need. I don't want to use the Grails static rendering plugins.

  Read the article

• What is the cost of object creating.

  - by Tony

  Hi If I have to choose between static method and creating an instance and use instance method, I will choose static methods always. but what is the detailed overhead of creating an instance? for example I saw a DAL which can be done with static classes but they choose to make it instance now in the BLL at every single call they call something like. new Customer().GetData(); how far this can be bad? Thanks

  Read the article

• Can I set a PHP class property from an existing variable?

  - by jasondavis

  I am trying to figure out how I want to handle settings in my PHP app. I have pretty much decide that I would like to use a Confg class file so it will be autoloaded and flexible in the future. Below is some stuff I was playing with. I know you cannot set a variable to popluate a Constant so I then try to use a public static property. Why can I not set public static $ip = $_SERVER['REMOTE_ADDR']; ?? <?php // config.class.php class Config { const URL = 'http://www.foo.com'; const DB_User = 'dbname'; public static $test = 'test string'; public static $ip = $_SERVER['REMOTE_ADDR']; } /////////////////////////////////////////////////////// //index.php // works echo Config::URL; // works echo Config::$test; // DOES NOT WORK echo Config::$ip; ?>

  Read the article

• WPF Binding not updating when binded object is updated

  - by Chris Klepeis

  I'm trying to bind to a custom control like so: <my:GanttChartTaskListView Name="ganttChartTaskListView1" ItemsSource="{Binding Source={x:Static local:TaskCollection.taskList}}" /> In my WPF Window constructor I add add an item to my taskList, when it loads I can see that item in my custom control, however, when I subsequently add items it does not update. I tried setting Mode=TwoWay, however, then it says the "Path" is required and I'm not familiar with binding like that (this is new to me). Here is my TaskCollection class: namespace ProjectManager { public static class TaskCollection { private static List<TaskItem> _taskList = new List<TaskItem>(); public static List<TaskItem> taskList { get {return _taskList; } set { _taskList = value; } } } } Any ideas? Is there a better / easier way to do this?

  Read the article

• how to make objects globally accessible?

  - by fayer

  i have this code: class IC_Core { /** * Database * @var IC_Database */ public static $db = NULL; /** * Core * @var IC_Core */ protected static $_instance = NULL; private function __construct() { } public static function getInstance() { if ( ! is_object(self::$_instance)) { self::$_instance = new self(); self::initialize(self::$_instance); } return self::$_instance; } private static function initialize(IC_Core $IC_Core) { self::$db = new IC_Database($IC_Core); } } but when i wanna access IC_Database with: $IC = IC_Core::getInstance(); $IC->db->add() // it says that its not an object. i think the problem lies in self::$db = new IC_Database($IC_Core); but i dont know how to make it work. could someone give me a hand=) thanks!

  Read the article

• A member variable's hashCode() value is different

  - by Jacques René Mesrine

  There's a piece of code that looks like this. The problem is that during bootup, 2 initialization takes place. (1) Some method does a reflection on ForumRepository & performs a newInstance() purely to invoke #setCacheEngine. (2) Another method following that invokes #start(). I am noticing that the hashCode of the #cache member variable is different sometimes in some weird scenarios. Since only 1 piece of code invokes #setCacheEngine, how can the hashCode change during runtime (I am assuming that a different instance will have a different hashCode). Is there a bug here somewhere ? public class ForumRepository implements Cacheable { private static CacheEngine cache; private static ForumRepository instance; public void setCacheEngine(CacheEngine engine) { cache = engine; } public synchronized static void start() { instance = new ForumRepository(); } public synchronized static void addForum( ... ) { cache.add( .. ); System.out.println( cache.hashCode() ); // snipped } public synchronized static void getForum( ... ) { ... cache.get( .. ); System.out.println( cache.hashCode() ); // snipped } }

  Read the article

• In a Visual Studio C++ project with /clr, are its dependencies also compiled to managed code?

  - by Michael

  To be a bit more clear. If I have a Visual Studio C++ solution that has two projects, say a static library with CLR support turned off, and a second project with CLR support turned on that depends on this static library, does the static library get compiled as managed code? What about libraries that the CLR project uses that are external to this solution, do they also get compiled as managed code?

  Read the article

• Timer in java ,time difference problem

  - by javatechi

  I want to create a timer for my app. The sample code is shown below. When the method datetwo() is called the same time in milliseconds is shown as there in the main method. Please help me out with this import java.util.Date; import java.util.Timer; public class TimerChe { Timer timer; static Date date = new Date(); static Date date2 = new Date(); public static void timerMethod(){ new Thread() { public void run() { try { while (true) { sleep(10000); datetwo(); } } catch (InterruptedException ex) { } } }.start(); } public static void datetwo() { System.out.println ("OK, It's time to do something!") ; System.out.println("The Time is " + date2.getTime() + " milliseconds since 1970/01/01"); } public static void main(String args[]) throws Exception { System.out.println("The Time is " + date.getTime() + " milliseconds since 1970/01/01" ); System.out.println ("Schedule something to do in the mean time.") ; timerMethod(); } }

  Read the article

• What's my best approach on this simple hierarchy Java Problem?

  - by Nazgulled

  First, I'm sorry for the question title but I can't think of a better one to describe my problem. Feel free to change it :) Let's say I have this abstract class Box which implements a couple of constructors, methods and whatever on some private variables. Then I have a couple of sub classes like BoxA and BoxB. Both of these implement extra things. Now I have another abstract class Shape and a few sub classes like Square and Circle. For both BoxA and BoxB I need to have a list of Shape objects but I need to make sure that only Square objects go into BoxA's list and only Circle objects go into BoxB's list. For that list (on each box), I need to have a get() and set() method and also a addShape() and removeShape() methods. Another important thing to know is that for each box created, either BoxA or BoxB, each respectively Shape list is exactly the same. Let's say I create a list of Square's named ls and two BoxA objects named boxA1 and boxA2. No matter what, both boxA1 and boxA2 must have the same ls list. This is my idea: public abstract class Box { // private instance variables public Box() { // constructor stuff } // public instance methods } public class BoxA extends Box { // private instance variables private static List<Shape> list; public BoxA() { // constructor stuff } // public instance methods public static List<Square> getList() { List<Square> aux = new ArrayList<Square>(); for(Square s : list.values()) { aux.add(s.clone()); // I know what I'm doing with this clone, don't worry about it } return aux; } public static void setList(List<Square> newList) { list = new ArrayList<Square>(newList); } public static void addShape(Square s) { list.add(s); } public static void removeShape(Square s) { list.remove(list.indexOf(s)); } } As the list needs to be the same for that type of object, I declared as static and all methods that work with that list are also static. Now, for BoxB the class would be almost the same regarding the list stuff. I would only replace Square by Triangle and the problem was solved. So, for each BoxA object created, the list would be only one and the same for each BoxB object created, but a different type of list of course. So, what's my problem you ask? Well, I don't like the code... The getList(), setList(), addShape() and removeShape() methods are basically repeated for BoxA and BoxB, only the type of the objects that the list will hold is different. I can't think of way to do it in the super class Box instead. Doing it statically too, using Shape instead of Square and Triangle, wouldn't work because the list would be only one and I need it to be only one but for each sub class of Box. How could I do this differently and better? P.S: I could not describe my real example because I don't know the correct words in English for the stuff I'm doing, so I just used a box and shapes example, but it's basically the same.

  Read the article

• C# ApplicationContext usage

  - by rd42

  Apologies if my terminology is off, I'm new to C#. I'm trying to use an ApplicationContext file to store mysql conn values, like dbname, username, password. The class with mysql conn string is "using" the namespace for the ApplicationContext, but when I print out the connection string, the values are making it. A friend said, "I'm not initializing it" but couldn't stay to expand on what "it" was. and the "Console.WriteLine("1");" in ApplicationContext.cs never shows up. Do I need to create an ApplicationContext object and the call Initialize() on that object? Thanks for any help. ApplicationContext.cs: namespace NewApplication.Context { class ApplicationContext { public static string serverName; public static string username; public static string password; public static void Initialize() { //need to read through config here try { Console.WriteLine("1"); XmlDocument xDoc = new XmlDocument(); xDoc.Load(".\\Settings.xml"); XmlNodeList serverNodeList = xDoc.GetElementsByTagName("DatabaseServer"); XmlNodeList usernameNodeList = xDoc.GetElementsByTagName("UserName"); XmlNodeList passwordNodeList = xDoc.GetElementsByTagName("Password"); } catch (Exception ex) { // MessageBox.Show(ex.ToString()); //TODO: Future write to log file username = "user"; password = "password"; serverName = "localhost"; } } } } MySQLManager.cs: note: dbname is the same as the username as you'll see in the code, I copied this from a friend who does that. using System; using System.Collections.Generic; using System.Linq; using System.Text; using MySql.Data; using MySql.Data.MySqlClient; using NewApplication.Context; namespace NewApplication.DAO { class MySQLManager { private static MySqlConnection conn; public static MySqlConnection getConnection() { if (conn == null || conn.State == System.Data.ConnectionState.Closed) { string connStr = "server=" + ApplicationContext.serverName + ";user=" + ApplicationContext.username + ";database=" + ApplicationContext.username + ";port=3306;password=" + ApplicationContext.password + ";"; conn = new MySqlConnection(connStr); try { Console.WriteLine("Connecting to MySQL... "); Console.WriteLine("Connection string: " + connStr + "\n"); conn.Open(); // Perform databse operations // conn.Close(); } catch (Exception ex) { Console.WriteLine(ex.ToString()); } } return conn; } } } and, thanks for still reading, this is the code that uses the two previous files: class LogDAO { MySqlConnection conn; public LogDAO() { conn = MySQLManager.getConnection(); } Thank you, rd42

  Read the article

• c# template member functions

  - by user3730583

  How can I define a template member function in C# For instance I will fill any collection which supports an Add(...) member function, please check out the sample code below public class CInternalCollection { public static void ExternalCollectionTryOne<T<int>>(ref T<int> ext_col, int para_selection = 0) { foreach (int int_value in m_int_col) { if (int_value > para_selection) ext_col.Add(int_value); } } public static void ExternalCollectionTryTwo<T>(ref T ext_col, int para_selection = 0) { foreach (int int_value in m_int_col) { if (int_value > para_selection) ext_col.Add(int_value); } } static int[] m_int_col = { 0, -1, -3, 5, 7, -8 }; } The ExternalCollectionTryOne<...(...) would be the preferred kind, because the int type can be explicit defined, but results in an error: Type parameter declaration must be an identifier not a type The type or namespace name 'T' could not be found (are you missing a using directive or an assembly reference?) The ExternalCollectionTryTwo<...(...) results in an error: 'T' does not contain a definition for 'Add' and no extension method 'Add' accepting a first argument of type 'T' could be found (are you missing a using directive or an assembly reference?)... I hope the problem is clear – any suggestions? ----------------------------- edit -------------------------- The answers with the interface ICollection<.. without a template member works fine and thanks all for this hint, but I still cannot define successfully a member template(generic) function So a more simpler example ... how can I define this public class CAddCollectionValues { public static void AddInt<T>(ref T number, int selection) { T new_T = new T(); //this line is just an easy demonstration to get a compile error with type T foreach (int i_value in m_int_col) { if (i_value > selection) number += i_value; //again the type T cannot be used } } static int[] m_int_col = { 0, -1, -3, 5, 7, -8 }; }

  Read the article

• Focus process window, ShowWindow vs System Tray

  - by ais

  I try open process window, this code work if window state is minimize, but if program in system tray window isn't opened. [DllImport("User32")] private static extern int SetForegroundWindow(IntPtr hwnd); [DllImport("User32")] private static extern bool ShowWindow(IntPtr hWnd, int nCmdShow); private static void ShowWindow(Process process) { ShowWindow(process.MainWindowHandle, SW_RESTORE); SetForegroundWindow(process.MainWindowHandle); }

  Read the article

< Previous Page | 166 167 168 169 170 171 172 173 174 175 176 177  | Next Page >