Search Results

Search found 4593 results on 184 pages for 'constructor injection'.

Page 127/184 | < Previous Page | 123 124 125 126 127 128 129 130 131 132 133 134  | Next Page >

  • Singletons and other design issues

    - by Ahmed Saleh
    I have worked using different languages like C++/Java and currently AS3. Most applications were computer vision, and small 2D computer games. Most companies that I have worked for, they use Singletons in a language like AS3, to retrieve elements or classes in an easy way. Their problem is basically they needs some variables or to call other functions from other classes. In a language like AS3, there is no private constructor, and they write a hacky code to prevent new instances. In Java and C++ I also faced the situation that I need to use other classe's members or to call their functions in different classes. The question is, is there a better or another design, to let other classes interact with each others without using singletons? I feel that composition is the answer, but I need more detailed solutions or design suggestions.

    Read the article

  • my .jar file won't do anything.

    - by David
    I created a program that more or less holds an array of strings as an object and randomly prints one. so basicaly class Happy { string[] namestrings = new string[#] constructor() { fill with some strings} public static void main (String[]arg) { create instance of class do some junk with it method that prints it } method that prints it {} another method } when i compile and run it on the command line it works fine but when on the comand line i type in jar -cf Happy.jar Fun.class i get a .jar file called Happy and when i click on it i get an error message that reads "the java Jar file happy could not be launched read the consol for possible error messages" I have a mac i'm running lepord if that makes a diference. Whats going on?

    Read the article

  • PHP OOP: Avoid Singleton/Static Methods in Domain Model Pattern

    - by sunwukung
    I understand the importance of Dependency Injection and its role in Unit testing, which is why the following issue is giving me pause: One area where I struggle not to use the Singleton is the Identity Map/Unit of Work pattern (Which keeps tabs on Domain Object state). //Not actual code, but it should demonstrate the point class Monitor{//singleton construction omitted for brevity static $members = array();//keeps record of all objects static $dirty = array();//keeps record of all modified objects static $clean = array();//keeps record of all clean objects } class Mapper{//queries database, maps values to object fields public function find($id){ if(isset(Monitor::members[$id]){ return Monitor::members[$id]; } $values = $this->selectStmt($id); //field mapping process omitted for brevity $Object = new Object($values); Monitor::new[$id]=$Object return $Object; } $User = $UserMapper->find(1);//domain object is registered in Id Map $User->changePropertyX();//object is marked "dirty" in UoW // at this point, I can save by passing the Domain Object back to the Mapper $UserMapper->save($User);//object is marked clean in UoW //but a nicer API would be something like this $User->save(); //but if I want to do this - it has to make a call to the mapper/db somehow $User->getBlogPosts(); //or else have to generate specific collection/object graphing methods in the mapper $UserPosts = $UserMapper->getBlogPosts(); $User->setPosts($UserPosts); Any advice on how you might handle this situation? I would be loathe to pass/generate instances of the mapper/database access into the Domain Object itself to satisfy DI - At the same time, avoiding that results in lots of calls within the Domain Object to external static methods. Although I guess if I want "save" to be part of its behaviour then a facility to do so is required in its construction. Perhaps it's a problem with responsibility, the Domain Object shouldn't be burdened with saving. It's just quite a neat feature from the Active Record pattern - it would be nice to implement it in some way.

    Read the article

  • Doubt in abstract classes

    - by mohit
    public abstract class Person { private String name; public Person(String name) { this.name = name; System.out.println("Person"); } public String getName() { return name; } abstract public String getDescription(); } public class Student extends Person { private String major; public Student(String name, String major) { super(name); this.major = major; } public String getMajor() { return major; } @Override public String getDescription() { return "student" + super.getName() + " having" + major; } } public class PersonTest { public static void main(String[] args) { Person person = new Student("XYZ", "ABC"); System.out.println(person.getDescription()); } } Ques: We cannot create objects of abstract classes, then why Person Constructor has been invoked, even its an abstract class?

    Read the article

  • Dynamically Loading a DLL

    - by TooFat
    I am trying to simply load a dll written in C# at run time and create an instance of a class in that dll. Assembly a = Assembly.LoadFrom(@"C:\Development\DaDll.dll"); Type type = a.GetType("FileReleaseHandler", true); TestInterface.INeeedHelp handler = Activator.CreateInstance(type) as TestInterface.INeeedHelp; No errors are thrown, and if I step through the code I can walk though the FileReleaseHandler Class as it executes the constructor but the value of handler is always null. What am I missing here? or even is there a better way I should be going about this?

    Read the article

  • C# property in a form class only accessable after formload event

    - by Spooky2010
    using vs2008, c# Howdy, Im instantiating and calling Form B from Form A. FormB has some custom properties, to allow me to pass it things like sqlAdaptors and dataset instances. When i instantiate and show Form B from Form A as a dialog form with a Using statement, it all works fine, but i find the properties i pass are not available in Form B until after the form_load event has fired. I was under the impression the properties when passed to a instantiated class should be available from a constructor, but this is not the case. If it try to access the properties before the form load event i get a null reference exception. Is this correct behavior ? It is very annoying. thanks for any help

    Read the article

  • Android and Google Maps API - Icons

    - by oriharel
    I want to place markers on the map. I want to use the standard Google Maps icons for markers. how do I use them? I don't want to create my own icons. I'm developing for Android. in the documentation they tell me to create a class that overrides ItemizedOverlay but in the constructor I'm asked to provide a drawable object. how do I point to the standard Google Maps ones? thanks.

    Read the article

  • Keep a Google Maps v3 Map Hidden, show when needed

    - by Dr1Ku
    Is there a way of preventing Google Maps (JS, v3) of being displayed from the get-go ? I do some pre-processing and would like to show my 'Loading' spinner until everything is good to go (more eloquently put, hide the map -- e.g. the container div -- until all preprocessing is complete -- at which point, show the map). Hooking to the map's 'idle' event doesn't help that much, since the map is already displayed when this event hits. I know that the container div gets inline-styled by GMaps after loading, my first idea is to clear out the style attr (whilst listening to 'idle'), but it would be interesting to see if there is a way of creating the map and not displaying it until all pre-processing is done. Maybe by using an argument to the new google.maps.Map constructor, or a MapOption ? Any thoughts on this ? Thank you in advance !

    Read the article

  • android java.lang.OutOfMemoryError

    - by xiangdream
    hi, all, when i download large data from website, i got this error information: I/global (20094): Default buffer size used in BufferedInputStream constructor. It would be better to be explicit if an 8k buffer is required. D/dalvikvm(20094): GC freed 6153 objects / 3650840 bytes in 335ms I/dalvikvm-heap(20094): Forcing collection of SoftReferences for 3599051-byte al location D/dalvikvm(20094): GC freed 320 objects / 11400 bytes in 144ms E/dalvikvm-heap(20094): Out of memory on a 3599051-byte allocation. I/dalvikvm(20094): "Thread-9" prio=5 tid=17 RUNNABLE I/dalvikvm(20094): | group="main" sCount=0 dsCount=0 s=0 obj=0x439b9480 I/dalvikvm(20094): | sysTid=25762 nice=0 sched=0/0 handle=4065496 anyone can help me?

    Read the article

  • C# how to dynamically cast an object?

    - by JL
    I am building a helper object that has a property called Mailer. In reality Mailer can be either a System.Net.Mail.MailMessage or a Mono.System.Net.Mail.MailMessage. So I would preferably only want 1 declaration of mailer. For example I don't want: private Mono.Mailing.MailMessage MonoMessage = new Mono.Mailing.MailMessage(); private System.Net.Mail.MailMessage MailMessage = new System.Net.Mail.MailMessage(); I would prefer object mailer; Then in constructor switch (software) { case EnunInternalMailingSoftware.dotnet: this.mailer = new System.Net.Mail.MailMessage(); break; case EnunInternalMailingSoftware.mono: this.mailer = new Mono.Mailing.MailMessage(); break; } The problem is that mailer has no properties at design time. So I can't compile my code. How can this be fixed, am I taking the right approach. Thanks in advance

    Read the article

  • Does a static object within a function introduce a potential race condition?

    - by Jeremy Friesner
    I'm curious about the following code: class MyClass { public: MyClass() : _myArray(new int[1024]) {} ~MyClass() {delete [] _myArray;} private: int * _myArray; }; // This function may be called by different threads in an unsynchronized manner void MyFunction() { static const MyClass _myClassObject; [...] } Is there a possible race condition in the above code? Specifically, is the compiler likely to generate code equivalent to the following, "behind the scenes"? void MyFunction() { static bool _myClassObjectInitialized = false; if (_myClassObjectInitialized == false) { _myClassObjectInitialized = true; _myClassObject.MyClass(); // call constructor to set up object } [...] } ... in which case, if two threads were to call MyFunction() nearly-simultaneously, then _myArray might get allocated twice, causing a memory leak? Or is this handled correctly somehow?

    Read the article

  • What characters are NOT escaped with a mysqli prepared statement?

    - by barfoon
    Hey everyone, I'm trying to harden some of my PHP code and use mysqli prepared statements to better validate user input and prevent injection attacks. I switched away from mysqli_real_escape_string as it does not escape % and _. However, when I create my query as a mysqli prepared statement, the same flaw is still present. The query pulls a users salt value based on their username. I'd do something similar for passwords and other lookups. Code: $db = new sitedatalayer(); if ($stmt = $db->_conn->prepare("SELECT `salt` FROM admins WHERE `username` LIKE ? LIMIT 1")) { $stmt->bind_param('s', $username); $stmt->execute(); $stmt->bind_result($salt); while ($stmt->fetch()) { printf("%s\n", $salt); } $stmt->close(); } else return false; Am I composing the statement correctly? If I am what other characters need to be examined? What other flaws are there? What is best practice for doing these types of selects? Thanks,

    Read the article

  • Vector of Object Pointers, general help and confusion

    - by Staypuft
    Have a homework assignment in which I'm supposed to create a vector of pointers to objects Later on down the load, I'll be using inheritance/polymorphism to extend the class to include fees for two-day delivery, next day air, etc. However, that is not my concern right now. The final goal of the current program is to just print out every object's content in the vector (name & address) and find it's shipping cost (weight*cost). My Trouble is not with the logic, I'm just confused on few points related to objects/pointers/vectors in general. But first my code. I basically cut out everything that does not mater right now, int main, will have user input, but right now I hard-coded two examples. #include <iostream> #include <string> #include <vector> using namespace std; class Package { public: Package(); //default constructor Package(string d_name, string d_add, string d_zip, string d_city, string d_state, double c, double w); double calculateCost(double, double); void Print(); ~Package(); private: string dest_name; string dest_address; string dest_zip; string dest_city; string dest_state; double weight; double cost; }; Package::Package() { cout<<"Constucting Package Object with default values: "<<endl; string dest_name=""; string dest_address=""; string dest_zip=""; string dest_city=""; string dest_state=""; double weight=0; double cost=0; } Package::Package(string d_name, string d_add, string d_zip, string d_city, string d_state, string r_name, string r_add, string r_zip, string r_city, string r_state, double w, double c){ cout<<"Constucting Package Object with user defined values: "<<endl; string dest_name=d_name; string dest_address=d_add; string dest_zip=d_zip; string dest_city=d_city; string dest_state=d_state; double weight=w; double cost=c; } Package::~Package() { cout<<"Deconstructing Package Object!"<<endl; delete Package; } double Package::calculateCost(double x, double y){ return x+y; } int main(){ double cost=0; vector<Package*> shipment; cout<<"Enter Shipping Cost: "<<endl; cin>>cost; shipment.push_back(new Package("tom r","123 thunder road", "90210", "Red Bank", "NJ", cost, 10.5)); shipment.push_back(new Package ("Harry Potter","10 Madison Avenue", "55555", "New York", "NY", cost, 32.3)); return 0; } So my questions are: I'm told I have to use a vector of Object Pointers, not Objects. Why? My assignment calls for it specifically, but I'm also told it won't work otherwise. Where should I be creating this vector? Should it be part of my Package Class? How do I go about adding objects into it then? Do I need a copy constructor? Why? What's the proper way to deconstruct my vector of object pointers? Any help would be appreciated. I've searched for a lot of related articles on here and I realize that my program will have memory leaks. Using one of the specialized ptrs from boost:: will not be available for me to use. Right now, I'm more concerned with getting the foundation of my program built. That way I can actually get down to the functionality I need to create. Thanks.

    Read the article

  • Can't get Angular Dart Router to work

    - by JesterXL
    I've tried this syntax in AngularDart 0.11.0: Angular Dart passing data from route service into a controller module.value(RouteInitializerFn, configureRoutes); void configureRoutes(Router router, RouteViewFactory views) { print("configureRoutes"); views.configure({ 'login': ngRoute( path: '/login', view: 'login/login.tpl.html'), 'today': ngRoute( path: '/today', view: '/today/today.tpl.html') }); However, my routing function never seems to get called. I've used both a print statement and breakpoint to no avail. When I attempt to call it like so: WorkoutLoggerApplication(this.rootScope, this.router) { print("WorkoutLoggerApplication::constructor"); new Future.delayed(new Duration(seconds: 2), () { router.go("login", {}); }); } I get: Bad state: Invalid route name: login I've tried 0.10.0, but no dice. I've also tried 3 varieties of the new bind function format, both also don't seem to ever fire the routing function.

    Read the article

  • LLVM Clang 5.0 explicit in copy-initialization error

    - by kevzettler
    I'm trying to compile an open source project on OSX that has only been tested on Linux. $: g++ -v Configured with: --prefix=/Applications/Xcode.app/Contents/Developer/usr --with-gxx-include-dir=/usr/include/c++/4.2.1 Apple LLVM version 5.0 (clang-500.2.79) (based on LLVM 3.3svn) Target: x86_64-apple-da I'm trying to compile with the following command line options g++ -MMD -Wall -std=c++0x -stdlib=libc++ -Wno-sign-compare -Wno-unused-variable -ftemplate-depth=1024 -I /usr/local/Cellar/boost/1.55.0/include/boost/ -g -O3 -c level.cpp -o obj-opt/level.o I am seeing several errors that look like this: ./square.h:39:70: error: chosen constructor is explicit in copy-initialization int strength = 0, double flamability = 0, map<SquareType, int> constructions = {}, bool ticking = false); The project states the following are requirements for the Linux setup. How can I confirm I'm making that? gcc-4.8.2 git libboost 1.5+ with libboost-serialize libsfml-dev 2+ (Ubuntu ppa that contains libsfml 2: ) freeglut-dev libglew-dev

    Read the article

  • Can there be two public section in a class? If yes then why ? And in which circumstances we do so?

    - by Abhi
    Dear all I have a doubt related to class. For example class A { public: A() { ..... ..... } void cleanup() { .... .... .... } public: UINT a; ULONG b; }; In the above example there are two public section, In first section i am defining constructor and the method and in the second section i am declaring data members. Does the above class i.e. A is correct. Can we do so? If yes then why we needed and in which circumstances we should use it? Also we can do the entire thing in one section then why un necessary we r taking two section...? Thanks and regards Abhineet Agarwal

    Read the article

  • Why isn't my log4net appender buffering?

    - by Eric
    I've created a custom log4net appender. It descends from log4net.Appender.SmtpAppender which descends from log4net.Appender.BufferingAppenderSkeleton. I programatically setup the following parameters in its constructor: this.Lossy = false; //don't drop any messages this.BufferSize = 3; //buffer up to 3 messages this.Threshold = log4net.Core.Level.Error; //append messages of Error or higher this.Evaluator = new log4net.Core.LevelEvaluator(Level.Off); //don't flush the buffer for any message, regardless of level I expect this would buffer 3 events of level Error or higher and deliver those events when the buffer is filled. However, I'm finding that the events are not buffered at all; instead, SendBuffer() is called immediately every time an error is logged. Is there a mistake in my configuration? Thanks

    Read the article

  • Explanation of output

    - by Anon
    My program class Building { Building() { System.out.print("b "); } Building(String name) { this(); System.out.print("bn " + name); } }; public class House extends Building { House() { System.out.print("h "); // this is line# 1 } House(String name) { this(); // This is line#2 System.out.print("hn " + name); } public static void main(String[] args) { new House("x "); } } We know that compiler will write a call to super() as the first line in the child class's constructor. Therefore should not the output be: b (call from compiler written call to super(), before line#2 b (again from compiler written call to super(),before line#1 ) h hn x But the output is b h hn x Why is that?

    Read the article

  • Android: automatically choose debug/release Maps api key?

    - by tomash
    Is it possible to automatically detect, which certificate was used for signing APK? I'd like to have both debug and release Maps certificates in application and pass valid one to MapView constructor. With such setup I will not make mistake while releasing application - I'm using debug certificate on emulator and my device, then sign with release one before sending app to Market. I was thinking about detecting my particular device or whether debugger is connected but it is not perfect. Maybe some file marking need for debug certificate? Is there any better way?

    Read the article

  • How do I override a Spring bean definition yet still reference the overriden bean?

    - by Kevin
    I'm attempting to implement a delegate Service provider by overriding the bean definition for the original service with my delegate Service. However, as the name would imply, the delegate Service needs a reference to the original service to delegate calls to. I'm having trouble figuring out how to override the bean definition while using the original bean def without running into a circular reference issue. For example: <!-- Original service def in spring-context.xml --> <bean id="service" class="com.mycompany.Service"/> <!-- Overridden definition in spring-plugin-context.xml --> <bean id="service" class="com.mycompany.DelegatedService"/> <constructor-arg ref="service"/> </bean> Is this possible?

    Read the article

  • Is there any performance issue using Row_Number to implement table paging in Sql Server 2008?

    - by majkinetor
    I want to implement table paging using this method: SET @PageNum = 2; SET @PageSize = 10; WITH OrdersRN AS ( SELECT ROW_NUMBER() OVER(ORDER BY OrderDate, OrderID) AS RowNum ,* FROM dbo.Orders ) SELECT * FROM OrdersRN WHERE RowNum BETWEEN (@PageNum - 1) * @PageSize + 1 AND @PageNum * @PageSize ORDER BY OrderDate ,OrderID; Is there anything I should be aware of ? Table has millions of records. Thx. EDIT: After using suggested MAXROWS method for some time (which works really really fast) I had to switch back to ROW_NUMBER method because of its greater flexibility. I am also very happy about its speed so far (I am working with View having more then 1M records with 10 columns). To use any kind of query I use following modification: PROCEDURE [dbo].[PageSelect] ( @Sql nvarchar(512), @OrderBy nvarchar(128) = 'Id', @PageNum int = 1, @PageSize int = 0 ) AS BEGIN SET NOCOUNT ON Declare @tsql as nvarchar(1024) Declare @i int, @j int if (@PageSize <= 0) OR (@PageSize > 10000) SET @PageSize = 10000 -- never return more then 10K records SET @i = (@PageNum - 1) * @PageSize + 1 SET @j = @PageNum * @PageSize SET @tsql = 'WITH MyTableOrViewRN AS ( SELECT ROW_NUMBER() OVER(ORDER BY ' + @OrderBy + ') AS RowNum ,* FROM MyTableOrView WHERE ' + @Sql + ' ) SELECT * FROM MyTableOrViewRN WHERE RowNum BETWEEN ' + CAST(@i as varchar) + ' AND ' + cast(@j as varchar) exec(@tsql) END If you use this procedure make sure u prevented sql injection.

    Read the article

  • Resizing an image with alpha channel

    - by Hafthor
    I am writing some code to generate images - essentially I have a source image that is large and includes transparent regions. I use GDI+ to open that image and add additional objects. What I want to do next is to save this new image much smaller, so I used the Bitmap constructor that takes a source Image object and a height and width, then saved that. I was expecting the alpha channel to be smoothed like the color channels, but this did not happen -- it did result in a couple of semitransparent pixels, but overall it is very blocky. What gives? Using img As New Bitmap("source100x100.png") ''// Drawing stuff Using simg As New Bitmap(img, 20, 20) simg.Save("target20x20.png") End Using End Using Edit: I think what I want is SuperSampling, like what Paint.NET does when set to "Best Quality"

    Read the article

  • how to read httpWebRequest's request stream in c#, i got error" the stream is not readable" ?

    - by sam
    hi i want to read request stream from a custom httpWebRequest class that inherits from httpWebRequest and i have tried to read the request stream in different stages but sitll not sure how to archieve that in the class,thanks very much for any help. This custom httpWebRequest is used to serilize soap message and i want to know what request has been sent in string format. I also implemented custom HttpRequestCreator,HttpWebResponse but till cant find a place/stage i can read the request stream. If i output everything in a memory stream then copy the content to request stream, anyone knows which stage i can do it in the constructor, BeginGetRequestStream,EndGetRequestStream or GetRequestStream?

    Read the article

  • How do I reference members of a single object passed to the View?

    - by Juxtaposed
    I'm new to MVC2 in ASP.NET/C#, so please forgive me if I misunderstand something. I have code similar to this in my Controller: var singleInstance = new Person("John"); ViewData["myInstance"] = singleInstance; return View(); So in my view, Index.aspx, I want to be able to reference members in that object. For example, Person has a member called Name, which is set in the constructor. In the view I want to get Person.Name from what is stored in the ViewData object. Ex.: <%= ViewData["myInstance"].name %> That doesn't work. The only real workaround I've found is to do something like this: <% var thePerson = ViewData["myInstance"]; print (or whatever the method is) thePerson.Name; %> Any help would be much appreciated... This was so much easier in PHP/Zend Framework... sigh

    Read the article

  • Spring @Value annotation not using defaults when property is not present

    - by garyj
    Hi All I am trying to use @Value annotation in the parameters of a constructor as follows: @Autowired public StringEncryptor( @Value("${encryptor.password:\"\"}") String password, @Value("${encryptor.algorithm:\"PBEWithMD5AndTripleDES\"}") String algorithm, @Value("${encryptor.poolSize:10}") Integer poolSize, @Value("${encryptor.salt:\"\"}") String salt) { ... } When the properties file is present on the classpath, the properties are loaded perfectly and the test executes fine. However when I remove the properties file from the classpath, I would have expected that the default values would have been used, for example poolSize would be set to 10 or algorithm to PBEWithMD5AndTripleDES however this is not the case. Running the code through a debugger (which would only work after changing @Value("${encryptor.poolSize:10}") Integer poolSize to @Value("${encryptor.poolSize:10}") String poolSize as it was causing NumberFormatExceptions) I find that the defaults are not being set and the parameters are in the form of: poolSize = ${encryptor.poolSize:10} or algorithm = ${encryptor.algorithm:"PBEWithMD5AndTripleDES"} rather than the expected poolSize = 10 or algorithm = "PBEWithMD5AndTripleDES" Based on SPR-4785 the notation such as ${my.property:myDefaultValue} should work. Yet it's not happening for me! Thank you

    Read the article

< Previous Page | 123 124 125 126 127 128 129 130 131 132 133 134  | Next Page >