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  • Accessing Application Scoped Bean Causes NullPointerException

    - by user2946861
    What is an Application Scoped Bean? I understand it to be a bean which will exist for the life of the application, but that doesn't appear to be the correct interpretation. I have an application which creates an application scoped bean on startup (eager=true) and then a session bean that tries to access the application scoped bean's objects (which are also application scoped). But when I try to access the application scoped bean from the session scoped bean, I get a null pointer exception. Here's excerpts from my code: Application Scoped Bean: @ManagedBean(eager=true) @ApplicationScoped public class Bean1 implements Serializable{ private static final long serialVersionUID = 12345L; protected ArrayList<App> apps; // construct apps so they are available for the session scoped bean // do time consuming stuff... // getters + setters Session Scoped Bean: @ManagedBean @SessionScoped public class Bean2 implements Serializable{ private static final long serialVersionUID = 123L; @Inject private Bean1 bean1; private ArrayList<App> apps = bean1.getApps(); // null pointer exception What appears to be happening is, Bean1 is created, does it's stuff, then is destroyed before Bean2 can access it. I was hoping using application scoped would keep Bean1 around until the container was shutdown, or the application was killed, but this doesn't appear to be the case.

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  • C# Different class objects in one list

    - by jeah_wicer
    I have looked around some now to find a solution to this problem. I found several ways that could solve it but to be honest I didn't realize which of the ways that would be considered the "right" C# or OOP way of solving it. My goal is not only to solve the problems but also to develop a good set of code standards and I'm fairly sure there's a standard way to handle this problem. Let's say I have 2 types of printer hardwares with their respective classes and ways of communicating: PrinterType1, PrinterType2. I would also like to be able to later on add another type if neccessary. One step up in abstraction those have much in common. It should be possible to send a string to each one of them as an example. They both have variables in common and variables unique to each class. (One for instance communicates via COM-port and has such an object, while the other one communicates via TCP and has such an object). I would however like to just implement a List of all those printers and be able to go through the list and perform things as "Send(string message)" on all Printers regardless of type. I would also like to access variables like "PrinterList[0].Name" that are the same for both objects, however I would also at some places like to access data that is specific to the object itself (For instance in the settings window of the application where the COM-port name is set for one object and the IP/port number for another). So, in short something like: In common: Name Send() Specific to PrinterType1: Port Specific to PrinterType2: IP And I wish to, for instance, do Send() on all objects regardless of type and the number of objects present. I've read about polymorphism, Generics, interfaces and such, but I would like to know how this, in my eyes basic, problem typically would be dealt with in C# (and/or OOP in general). I actually did try to make a base class, but it didn't quite seem right to me. For instance I have no use of a "string Send(string Message)" function in the base class itself. So why would I define one there that needs to be overridden in the derived classes when I would never use the function in the base class ever in the first place? I'm really thankful for any answers. People around here seem very knowledgeable and this place has provided me with many solutions earlier. Now I finally have an account to answer and vote with too. EDIT: To additionally explain, I would also like to be able to access the objects of the actual printertype. For instance the Port variable in PrinterType1 which is a SerialPort object. I would like to access it like: PrinterList[0].Port.Open() and have access to the full range of functionality of the underlaying port. At the same time I would like to call generic functions that work in the same way for the different objects (but with different implementations): foreach (printer in Printers) printer.Send(message)

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  • accessing objective c++ methods

    - by Sreelal
    Hi, I am developing an application for iPhone.I am using some objective c++ classes with .h and .mm extensions.My problem is that when i am trying to access a method in .mm file from .m file i am geting a warning that "No '-methodname' found".how can i resolve this warnings Thanks in advance

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  • JQuery/AJAX: Loading external DIVs using dynamic content

    - by ticallian
    I need to create a page that will load divs from an external page using Jquery and AJAX. I have come across a few good tutorials, but they are all based on static content, my links and content are generated by PHP. The main tutorial I am basing my code on is from: http://yensdesign.com/2008/12/how-to-load-content-via-ajax-in-jquery/ The exact function i need is as follows: Main page contains a permanent div listing some links containing a parameter. Upon click, link passes parameter to external page. External page filters recordset against parameter and populates div with results. The new div contains a new set of links with new parameters. The external div is loaded underneath the main pages first div. Process can then be repeated creating a chain of divs under each other. The last div in the chain will then direct to a new page collating all the previously used querystrings. I can handle all of the PHP work with populating the divs on the main and external pages. It's the JQuery and AJAX part i'm struggling with. $(document).ready(function(){ var sections = $('a[id^=link_]'); // Link that passes parameter to external page var content = $('div[id^=content_]'); // Where external div is loaded to sections.click(function(){ //load selected section switch(this.id){ case "div01": content.load("external.php?param=1 #section_div01"); break; case "div02": content.load("external.php?param=2 #section_div02"); break; } }); The problem I am having is getting JQuery to pass the dynamically generated parameters to the external page and then retrieve the new div. I can currently only do this with static links (As above).

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  • 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

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  • Do I Need To Reference Indirect DLLs

    - by ChloeRadshaw
    Suppose I have DLLA which is a standalone library that contains classes I use I have DLLB that references DLLA I now have DLLC that references DLLB - Why is it that DLLC also needs a reference to DLLA? Can I not have VS2005 build a dll which contains all the assemblies it needs embedded inside it?

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  • Can I use an ORM (as Subsonic) to work with an API?

    - by Gabotron
    Hello ... I´m new to ORMs and I have a new project I´ll do in .Net MVC. In the Model Layer I´ll create my classes: Videos and I´ll work with APIs as a DataLayer (BrightCove & YouTube APIs). So, I dont have a Relational Database as a Data Layer. Is it possible to work with an ORM (as Subsonic)? Thanks!

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  • Abstract over X

    - by Bruno Bieth
    Sorry for this english related question but I only came across that expression in the context of IT. What does abstracting over something mean ? For example abstracting over objects or abstracting over classes. Thanks

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  • Main point of Application Delegate class

    - by ahmet732
    What's the main point behind putting variables and method signatures inside ApplicationDelegate.h in Objective-C ? By doing this, all those methods and variables are seen by another view controller classes? Is that the point? And also: is there only one application delegate class inside each project?

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  • Ruby: Allowing a module to have settings

    - by JP
    If I'm building a library in ruby, what's the best way to allow users of the library to set module-wide settings that will be available to all sub classes etc of the library? A good example would be if I'm writing a library for posting to a webservice: TheService::File.upload("myfile.txt") # Uploads anonymously TheService::Settings.login("myuser","mypass") # Or any other similar way of doing this TheService::File.upload("myfile.txt") # Uploads as 'myuser' The idea would be that unless TheService::Settings.logout is called then all TheService operations would be conducted under myuser's account. Any ideas?

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  • Java How to find a value in a linked list iteratively and recursively

    - by Roxy
    Hi I have a method that has a reference to a linked list and a int value. So, this method would count and return how often the value happens in the linked list. So, I decided to make a class, public class ListNode{ public ListNode (int v, ListNode n) {value = v; next = n;) public int value; public ListNode next; } Then, the method would start with a public static int findValue(ListNode x, int valueToCount){ // so would I do it like this?? I don't know how to find the value, // like do I check it? for (int i =0; i< x.length ;i++){ valueToCount += valueToCount; } So, I CHANGED this part, If I did this recursively, then I would have public static int findValue(ListNode x, int valueToCount) { if (x.next != null && x.value == valueToCount { return 1 + findValue(x, valueToCount);} else return new findvalue(x, valueToCount); SO, is the recursive part correct now?

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  • Java application profiling / tracking

    - by sarav
    I have a closed source Java application for which vendor has provided APIs for customization. As I have no other documents, i rely completely on the API's javadoc. I want to trace what methods are actually called in different classes for a particular use case. Is there any way to do that with eclipse?

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  • jquery cousin element

    - by salmane
    I am trying to locate the closest element that contains a class....this is in an effort to find the "cousin" of the current element that i have.. the following did not work : $('myelement').closest ('*:has(.class1)').find('class_cousin') I am using the * in closest since i am not sure what type element is the one i am looking for nor do I know if it has any classes or ID ( i am trying to keep it general for a plugin) any idea how I could do it? thank you

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  • Access to and availability of private member functions in C++

    - by David
    I am wandering the desert of my brain. I'm trying to write something like the following: class MyClass { // Peripherally Related Stuff public: void TakeAnAction(int oneThing, int anotherThing) { switch(oneThing){ case THING_A: TakeThisActionWith(anotherThing); break; //cases THINGS_NOT_A: }; }; private: void TakeThisActionWith(int thing) { string outcome = new string; outcome = LookUpOutcome(thing); // Do some stuff based on outcome return; } string LookUpOutcome(int key) { string oc = new string; oc = MyPrivateMap[key]; return oc; } map<int, string> MyPrivateMap; Then in the .cc file where I am actually using these things, while compiling the TakeAnAction section, it [CC, the solaris compiler] throws an an error: 'The function LookUpOutcome must have a prototype' and bombs out. In my header file, I have declared 'string LookUpOutcome(int key);' in the private section of the class. I have tried all sorts of variations. I tried to use 'this' for a little while, and it gave me 'Can only use this in non-static member function.' Sadly, I haven't declared anything static and these are all, putatively, member functions. I tried it [on TakeAnAction and LookUp] when I got the error, but I got something like, 'Can't access MyPrivateMap from LookUp'. MyPrivateMap could be made public and I could refer to it directly, I guess, but my sensibility says that is not the right way to go about this [that means that namespace scoped helper functions are out, I think]. I also guess I could just inline the lookup and subsequent other stuff, but my line-o-meter goes on tilt. I'm trying desperately not to kludge it.

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  • How do I remove an old JPanel and add a new one?

    - by Roman
    I would like to remove an old JPanel from the Window (JFrame) and add a new one. How should I do it? I tried the following: public static void showGUI() { JFrame frame = new JFrame("Colored Trails"); frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); frame.add(partnerSelectionPanel); frame.setSize(600,400); frame.setVisible(true); } private static void updateGUI(final int i, final JLabel label, final JPanel partnerSelectionPanel) { SwingUtilities.invokeLater( new Runnable() { public void run() { label.setText(i + " seconds left."); } partnerSelectionPanel.setVisible(false); \\ <------------ } ); } So, my code update the "old" JPanel and them it makes the whole JPanel invisible. It was the idea. But it does not work. The compiler complains about the line indicated with "<------------". It writes: <identifier> expected, illegal start of type.

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  • Container of Generic Types in java

    - by Cyker
    I have a generic class Foo<T> and parameterized types Foo<String> and Foo<Integer>. Now I want to put different parameterized types into a single ArrayList. What is the correct way of doing this? Candidate 1: public class MMM { public static void main(String[] args) { Foo<String> fooString = new Foo<String>(); Foo<Integer> fooInteger = new Foo<Integer>(); ArrayList<Foo<?> > list = new ArrayList<Foo<?> >(); list.add(fooString); list.add(fooInteger); for (Foo<?> foo : list) { // Do something on foo. } } } class Foo<T> {} Candidate 2: public class MMM { public static void main(String[] args) { Foo<String> fooString = new Foo<String>(); Foo<Integer> fooInteger = new Foo<Integer>(); ArrayList<Foo> list = new ArrayList<Foo>(); list.add(fooString); list.add(fooInteger); for (Foo foo : list) { // Do something on foo. } } } class Foo<T> {} In a word, it is related to the difference between Foo<?> and the raw type Foo. Update: Grep What is the difference between the unbounded wildcard parameterized type and the raw type? on this link may be helpful.

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