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• How to include all objects of an archive in a shared object?

  - by Didier Trosset

  When compiling our project, we create several archives (static libraries), say liby.a and libz.a that each contains an object file defining a function y_function() and z_function(). Then, these archives are joined in a shared object, say libyz.so, that is one of our main distributable target. g++ -fPIC -c -o y.o y.cpp ar cr liby.a y.o g++ -fPIC -c -o z.o z.cpp ar cr libz.a z.o g++ -shared -L. -ly -lz -o libyz.so When using this shared object into the example program, say x.c, the link fails because of an undefined references to functions y_function() and z_function(). g++ x.o -L. -lyz -o xyz It works however when I link the final executable directly with the archives (static libraries). g++ x.o -L. -ly -lz -o xyz My guess is that the object files contained in the archives are not linked into the shared library because they are not used in it. How to force inclusion? Edit: Inclusion can be forced using --whole-archive ld option. But if results in compilation errors: g++ -shared '-Wl,--whole-archive' -L. -ly -lz -o libyz.so /usr/lib/libc_nonshared.a(elf-init.oS): In function `__libc_csu_init': (.text+0x1d): undefined reference to `__init_array_end' /usr/bin/ld: /usr/lib/libc_nonshared.a(elf-init.oS): relocation R_X86_64_PC32 against undefined hidden symbol `__init_array_end' can not be used when making a shared object /usr/bin/ld: final link failed: Bad value Any idea where this comes from?

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• Lazarus Pascal - DB Connection - clarification

  - by itsols

  The following code is from the docs here: Program ConnectDB var AConnection : TSQLConnection; Procedure CreateConnection; begin AConnection := TIBConnection.Create(nil); AConnection.Hostname := 'localhost'; AConnection.DatabaseName := '/opt/firebird/examples/employee.fdb'; AConnection.UserName := 'sysdba'; AConnection.Password := 'masterkey'; end; begin CreateConnection; AConnection.Open; if Aconnection.Connected then writeln('Succesful connect!') else writeln('This is not possible, because if the connection failed, ' + 'an exception should be raised, so this code would not ' + 'be executed'); AConnection.Close; AConnection.Free; end. The main body of the code makes sense to me BUT I don't get where TSQLConnection came from. I cannot use CTRL + Space to autocomplete it either, which means my program has no reference to it. I'm trying to connect to Postgres by the way. Can someone please state what TSQLConnection is? Thanks!

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• 'Forward-Compatible' Program Design

  - by Jeffrey Kern

  The majority of my questions I've asked here so far on StackOverflow have been how to implement individual concepts and techniques towards developing a software-based NES clone via the XNA environment. The small samples that I've thrown together on my PC work relatively great and everything. Except I hit a brick wall. How do I merge all of these samples together. Having proof-of-concept is amazing, except when you need it to go beyond just that. I now have samples strewn about that I'm trying to merge, some of them incomplete. And now I'm stuck with the chicken-and-the-egg situation of where I would like to incorporate these samples together, to make sure they work, but I cannot without test data. And I don't have tools to create test data, because they'd need to be based off of the individual pieces that need to be put together. In my mind, I'm having nightmares with circular reference. For my sample data, I am hoping to save it in XML and write a specification - and then make sample data by hand - but I'm too paranoid of manually creating an XML file full of incorrect data and blaming it on my code, or vice-versa. It doesn't help that the end-result of my work is graphic-oriented, which makes it interseting how a graphic on the screen can be visualized in XML Nodes. I guess, my question is this: What design patterns and disciplines exist in the coding world that address this type of concern? I've always relied on brute-force coding and restarting a project with a whole new code base in attempts to further along my goals, but I doubt that would be the best way to do so. Within my college career, the majority of my programming was to work on simple projects that came out of a book, or with a given correct data set and a verifyable result. I don't have that, as my own design documents that I am going by could be terribly wrong.

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• Are MEF's ComposableParts contracts instance-based?

  - by Dave

  I didn't really know how to phrase the title of my questions, so my apologies in advance. I read through parts of the MEF documentation to try to find the answer to my question, but couldn't find it. I'm using ImportMany to allow MEF to create multiple instances of a specific plugin. That plugin Imports several parts, and within calls to a specific instance, it wants these Imports to be singletons. However, what I don't want is for all instances of this plugin to use the same singleton. For example, let's say my application ImportManys Blender appliances. Every time I ask for one, I want a different Blender. However, each Blender Imports a ControlPanel. I want each Blender to have its own ControlPanel. To make things a little more interesting, each Blender can load BlendPrograms, which are also contained within their own assemblies, and MEF takes care of this loading. A BlendProgram might need to access the ControlPanel to get the speed, but I want to ensure that it is accessing the correct ControlPanel (i.e. the one that is associated with the Blender that is associated with the program!) This diagram might clear things up a little bit: As the note shows, I believe that the confusion could come from an inherently-poor design. The BlendProgram shouldn't touch the ControlPanel directly, and instead perhaps the BlendProgram should get the speed via the Blender, which will then delegate the request to its ControlPanel. If this is the case, then I assume the BlendProgram needs to have a reference to a specific Blender. In order to do this, is the right way to leverage MEF and use an ImportingConstructor for BlendProgram, i.e. [ImportingConstructor] public class BlendProgram : IBlendProgram { public BlendProgram( Blender blender) {} } And if this is the case, how do I know that MEF will use the intended Blender plugin?

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• C++ Multiple inheritance with interfaces?

  - by umanga

  Greetings all, I come from Java background and I am having difficulty with multiple inheritance. I have an interface called IView which has init() method.I want to derive a new class called PlaneViewer implementing above interface and extend another class. (QWidget). My implementation is as: IViwer.h (only Header file , no CPP file) : #ifndef IVIEWER_H_ #define IVIEWER_H_ class IViewer { public: //IViewer(); ///virtual //~IViewer(); virtual void init()=0; }; #endif /* IVIEWER_H_ */ My derived class. PlaneViewer.h #ifndef PLANEVIEWER_H #define PLANEVIEWER_H #include <QtGui/QWidget> #include "ui_planeviewer.h" #include "IViewer.h" class PlaneViewer : public QWidget , public IViewer { Q_OBJECT public: PlaneViewer(QWidget *parent = 0); ~PlaneViewer(); void init(); //do I have to define here also ? private: Ui::PlaneViewerClass ui; }; #endif // PLANEVIEWER_H PlaneViewer.cpp #include "planeviewer.h" PlaneViewer::PlaneViewer(QWidget *parent) : QWidget(parent) { ui.setupUi(this); } PlaneViewer::~PlaneViewer() { } void PlaneViewer::init(){ } My questions are: Is it necessary to declare method init() in PlaneViewer interface also , because it is already defined in IView? 2.I cannot complie above code ,give error : PlaneViewer]+0x28): undefined reference to `typeinfo for IViewer' collect2: ld returned 1 exit status Do I have to have implementation for IView in CPP file?

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• How to manipulate *huge* amounts of data

  - by Alejandro

  Hi there! I'm having the following problem. I need to store huge amounts of information (~32 GB) and be able to manipulate it as fast as possible. I'm wondering what's the best way to do it (combinations of programming language + OS + whatever you think its important). The structure of the information I'm using is a 4D array (NxNxNxN) of double-precission floats (8 bytes). Right now my solution is to slice the 4D array into 2D arrays and store them in separate files in the HDD of my computer. This is really slow and the manipulation of the data is unbearable, so this is no solution at all! I'm thinking on moving into a Supercomputing facility in my country and store all the information in the RAM, but I'm not sure how to implement an application to take advantage of it (I'm not a professional programmer, so any book/reference will help me a lot). An alternative solution I'm thinking on is to buy a dedicated server with lots of RAM, but I don't know for sure if that will solve the problem. So right now my ignorance doesn't let me choose the best way to proceed. What would you do if you were in this situation? I'm open to any idea. Thanks in advance!

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• JUnit confusion: use 'extend Testcase' or '@Test' ?

  - by Rabarberski

  I've found the proper use (or at least the documentation) of JUnit very confusing. This question serves both as a future reference and as a real question. If I've understood correctly, there are two main approaches to create and run a JUnit test: Approach A: create a class that extends TestCase, and start test methods with the word test. When running the class as a JUnit Test (in Eclipse), all methods starting with the word test are automatically run. import junit.framework.TestCase; public class DummyTestA extends TestCase { public void testSum() { int a = 5; int b = 10; int result = a + b; assertEquals(15, result); } } Approach B: create a 'normal' class and prepend a @Test annotation to the method. Note that you do NOT have to start the method with the word test. import org.junit.*; import static org.junit.Assert.*; public class DummyTestB { @Test public void Sum() { int a = 5; int b = 10; int result = a + b; assertEquals(15, result); } } Mixing the two seems not to be a good idea, see e.g. this stackoverflow question: Now, my questions(s): What is the preferred approach, or when would you use one instead of the other? Approach B allows for testing for exceptions by extending the @Test annotation like in @Test(expected = ArithmeticException.class). But how do you test for exceptions when using approach A? When using approach A, you can group a number of test classes in a test suite. TestSuite suite = new TestSuite("All tests");<br/> suite.addTestSuite(DummyTestA.class); suite.addTestSuite(DummyTestAbis.class);` But this can't be used with approach B (since each testclass should subclass TestCase). What is the proper way to group tests for approach B?

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• How does a client find the port number of a server?

  - by Jonathan

  Hello all, I am currently learning about basic networking in java. I have been playing around with the server and client relationship between two of my computers. However, I cannot figure out how distributed programs (say, a videogame), can not only find the 'host' computer, but also the port number on which the server is running in order to create a Socket between the two computers. The only way I really see to create a Socket is with an already known IP Address, and with a known port number. How do you search a LAN network for another computer (host) searching for clients? How do you determine what port the server is located on without 'pinging' all available ports for a response (which, I understand, is bad form... Something about 'server attack'...)? In such a situation as a video game, there can be any number of computers on the same network, and any number of them might be attempting to host, or otherwise running the application. Any other important information, or perhaps reference to a more detailed tutorial than the one I am using, regarding making connections on so very little information on the client side would be appreciated. Many thanks, Jonathan

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• ViewModel Views relation/link/syncroniztion

  - by mehran

  Third try to describing problem: Try 1: Sunchronizing view model and view Try2: WPF ViewModel not active presenter Try3: I have some class for view models: public class Node : INotifyPropertyChanged { Guid NodeId { get; set; } public string Name { get; set; } } public class Connection: INotifyPropertyChanged { public Node StartNode { get; set; } public Node EndNode { get; set; } } public class SettingsPackModel { public List<Node> Nodes { get; private set; } public List<Connection> Connections { get; private set; } } I also have some templates to displays these models: <DataTemplate DataType="{x:Type vm:Node}">…</DataTemplate> <DataTemplate DataType="{x:Type vm:Connection}"> <my:ConnectionElment StartNodeElment="???" EndNodeElment="???"> </my:ConnectionElment> <DataTemplate> But the problem is that DataTemplate for Connection need reference ot two element of type UIElement , how can I pass these two, how can I fill ??? in above expression?

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• PHP: Next Available Value in an Array, starting with a non-indexed value

  - by Erik Smith

  I've been stumped on this PHP issue for about a day now. Basically, we have an array of hours formatted in 24-hour format, and an arbitrary value ($hour) (also a 24-hour). The problem is, we need to take $hour, and get the next available value in the array, starting with the value that immediately proceeds $hour. The array might look something like: $goodHours = array('8,9,10,11,12,19,20,21). Then the hour value might be: $hour = 14; So, we need some way to know that 19 is the next best time. Additionally, we might also need to get the second, third, or fourth (etc) available value. The issue seems to be that because 14 isn't a value in the array, there is not index to reference that would let us increment to the next value. To make things simpler, I've taken $goodHours and repeated the values several times just so I don't have to deal with going back to the start (maybe not the best way to do it, but a quick fix). I have a feeling this is something simple I'm missing, but I would be so appreciative if anyone could shed some light. Erik

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• ASP.NET MVC Newbie: why isn't my model available when creating a strongly-typed view?

  - by Rax Olgud

  I'm starting with ASP.NET MVC, and working with NerdDinner as reference. I did the following: Created a new project Added a couple of tables Created LINQ to SQL for them Created a new controller My Models directory now contains MyModel.dbml, under which I have MyModel.designer.cs, that contains classes for models relating to both of my tables (let's call them Categories and Products). Now, under my new controller, I would like to create a strongly typed view. So for example I have the following code in my controller (for my application I must work by name, and the "Name" field is unique): public ActionResult Details(string name) { MyModelDataContext db = new MyModelDataContext(); Product user = db.Products.Single(t => t.Name == name); return View(user); } I would like to create a strongly-typed view. So I right-click the line "return View(user)", and choose "Add View...". I click "Create a strongly-typed view". When I click the dropdown of "View data class", I don't see my models, but only: MyProject.Controllers.AccountMembershipService MyProject.Controllers.FormsAuthenticationService What am I missing?

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• i want to convert my aspx.cs to dll

  - by jay rathod

  i have a default.aspx page: <%@ Page Language="C#" AutoEventWireup="true" CodeFile="Default.aspx.cs" Inherits="_Default" %> <!DOCTYPE html> <html xmlns="http://www.w3.org/1999/xhtml"> <head runat="server"> <title></title> </head> <body> <form id="form1" runat="server"> <div> <asp:Button ID="btn" runat="server" Text="clicke here" OnClick="btn_Click"/> <asp:TextBox ID="txt" runat="server"></asp:TextBox> <asp:Label runat="server" ID="lbl"></asp:Label> </div> </div> </form> </body> </html> and default.aspx.cs : public partial class _Default : System.Web.UI.Page { string test; protected void Page_Load(object sender, EventArgs e) { } protected void btn_Click(object sender, EventArgs e) { test = txt.Text; lbl.Text = test; } } now i want to make the dll of my default.aspx.cs file and remove it from the website and give the reference of it. so how can i do this??

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• WPF - How to stop an ItemsControl psuedo-grid's columns from dancing/jumping around during layout

  - by Drew Noakes

  Several other questions on SO have come to the same conclusion I have -- using an ItemsControl with a DataTemplate for each item constructed to position items such that they resemble a grid is much simpler (especially to format) than using a ListView. The code resembles: <StackPanel Grid.IsSharedSizeScope="True"> <!-- Header --> <Grid> <Grid.ColumnDefinitions> <ColumnDefinition Width="Auto" SharedSizeGroup="Column1" /> <ColumnDefinition Width="Auto" SharedSizeGroup="Column2" /> </Grid.ColumnDefinitions> <TextBlock Grid.Column="0" Text="Column Header 1" /> <TextBlock Grid.Column="1" Text="Column Header 2" /> </Grid> <!-- Items --> <ItemsControl ItemsSource="{Binding Path=Values, Mode=OneWay}"> <ItemsControl.ItemTemplate> <DataTemplate> <Grid> <Grid.ColumnDefinitions> <ColumnDefinition Width="Auto" SharedSizeGroup="Column1" /> <ColumnDefinition Width="Auto" SharedSizeGroup="Column2" /> </Grid.ColumnDefinitions> <TextBlock Grid.Column="0" Text="{Binding ColumnProperty1}" /> <TextBlock Grid.Column="1" Text="{Binding ColumnProperty2}" /> </Grid> </DataTemplate> </ItemsControl.ItemTemplate> </ItemsControl> </StackPanel> The problem I'm seeing is that whenever I swap the object to which the ItemsSource is bound (it's an ObservableCollection that I replace the reference to, rather than clear and re-add), the entire 'grid' dances about for a few seconds. Presumably it is making a few layout passes to get all the Auto-width columns to match up. This is very distracting for my users and I'd like to get it sorted out. Has anyone else seen this?

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• Why does Microsoft advise against readonly fields with mutable values?

  - by Weeble

  In the Design Guidelines for Developing Class Libraries, Microsoft say: Do not assign instances of mutable types to read-only fields. The objects created using a mutable type can be modified after they are created. For example, arrays and most collections are mutable types while Int32, Uri, and String are immutable types. For fields that hold a mutable reference type, the read-only modifier prevents the field value from being overwritten but does not protect the mutable type from modification. This simply restates the behaviour of readonly without explaining why it's bad to use readonly. The implication appears to be that many people do not understand what "readonly" does and will wrongly expect readonly fields to be deeply immutable. In effect it advises using "readonly" as code documentation indicating deep immutability - despite the fact that the compiler has no way to enforce this - and disallows its use for its normal function: to ensure that the value of the field doesn't change after the object has been constructed. I feel uneasy with this recommendation to use "readonly" to indicate something other than its normal meaning understood by the compiler. I feel that it encourages people to misunderstand the meaning of "readonly", and furthermore to expect it to mean something that the author of the code might not intend. I feel that it precludes using it in places it could be useful - e.g. to show that some relationship between two mutable objects remains unchanged for the lifetime of one of those objects. The notion of assuming that readers do not understand the meaning of "readonly" also appears to be in contradiction to other advice from Microsoft, such as FxCop's "Do not initialize unnecessarily" rule, which assumes readers of your code to be experts in the language and should know that (for example) bool fields are automatically initialised to false, and stops you from providing the redundancy that shows "yes, this has been consciously set to false; I didn't just forget to initialize it". So, first and foremost, why do Microsoft advise against use of readonly for references to mutable types? I'd also be interested to know: Do you follow this Design Guideline in all your code? What do you expect when you see "readonly" in a piece of code you didn't write?

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• Force a view change from a button when using UITabBarController

  - by user342197

  Hello - When using a UITabBarController, when the user enters some data on View1 and presses a button, I need to perform some calculations and present the results on View2. I have an AppDelegate, View1Controller, View2Controller, and View3Controller (View3 is a basically static view). My AppDelgate declares UITabBarController *rootController; On View1, I have the calculations being performed in an IBAction for buttonPressed; however, I can't seem to force the view to switch to View2 programmatically. I have done a lot of searching for similar problems, and think I should be doing something like "self.rootController.selectedIndex = 1"; however,when I do this from within buttonPressed on my View1Controller, I get an error "request for member rootController in something not in a structure or union". I think I'm missing something basic here... probably need do do something with my AppDelegate, but I'm banging my head against the wall. Can anyone provide some guidance in this situation...like key things I should do in View1Controller header and implementation with reference to my AppDelgate? Thank you!

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• Flash Without a SWF File?

  - by PeterAllenWebb

  Is there any way to embed Flash completely in HTML, without reference to an external SWF file? I ask because I would like to send an HTML file as an email attachment that the recipient will open in a browser and fill out as a form. The last step is that they will copy the result to their clipboard, paste it into a new message, and email it back. I cannot reliably copy to the clipboard with JavaScript because of the security issues, but there are simple Flash apps to add that capability. I know I could just display the response text (which will be Base64 encoded) to the recipient and have them copy/paste, but it would be nice to provide this small convenience to them. Also, so you are aware, the text is often too large to include in an email using mailto. Yes. This needs to be done via email. The users have slow, occasional satellite email access and no other data connection to the interwebs. To make things worse, I cannot make them install anything. It is a difficult situation.

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• Image resizing - sometimes very poor quality?!

  - by eWolf

  I'm resizing some images to the screen resolution of the user; if the aspect ratio is wrong, the image should be cut. My code looks like this: protected void ConvertToBitmap(string filename) { var origImg = System.Drawing.Image.FromFile(filename); var widthDivisor = (double)origImg.Width / (double)System.Windows.Forms.Screen.PrimaryScreen.Bounds.Width; var heightDivisor = (double)origImg.Height / (double)System.Windows.Forms.Screen.PrimaryScreen.Bounds.Height; int newWidth, newHeight; if (widthDivisor < heightDivisor) { newWidth = (int)((double)origImg.Width / widthDivisor); newHeight = (int)((double)origImg.Height / widthDivisor); } else { newWidth = (int)((double)origImg.Width / heightDivisor); newHeight = (int)((double)origImg.Height / heightDivisor); } var newImg = origImg.GetThumbnailImage(newWidth, newHeight, null, IntPtr.Zero); newImg.Save(this.GetBitmapPath(filename), System.Drawing.Imaging.ImageFormat.Bmp); } In most cases, this works fine. But for some images, the result has an extremely poor quality. It looks like the would have been resized to something very small (thumbnail size) and enlarged again.. But the resolution of the image is correct. What can I do? Example orig image: Example resized image: Note: I have a WPF application but I use the WinForms function for resizing because it's easier and because I already need a reference to System.Windows.Forms for a tray icon.

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• boost::shared_ptr in Objective-C++

  - by John Smith

  This is a better understanding of a question I had earlier. I have the following Objective-C++ object @interface OCPP { MyCppobj * cppobj; } @end @implementation OCPP -(OCPP *) init { cppobj = new MyCppobj; } @end Then I create a completely differently obj which needs to use cppobj in a boost::shared_ptr (I have no choice in this matter, it's part of a huge library which I cannot change) @interface NOBJ -(void) use_cppobj_as_shared_ptr { //get an OCPP obj called occ from somewhere.. //troubling line here } @end I have tried the following and that failed: I tried synthesising cppobj. Then I created a shared_ptr in "troubling line" in the following way: MyCppobj * cpp = [occ cppobj]; bsp = boost::shared_ptr<MyCppobj>(cpp); It works fine first time around. Then I destroy the NOBJ and recreate it. When I for cppobj it's gone. Presumably shared_ptr decided it's no longer needed and did away with it. So I need help. How can I keep cppobj alive? Is there a way to destroy bsp (or it's reference to cppobj) without destroying cppobj?

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• How do I grab and use a variables coming back through ValueList from an AJAX call?

  - by Mel

  I'm trying the following code to execute a search and it's not working. On the search.cfm page, the only value coming back is the value I input into the search field (even if I click an autosuggest value, it's not coming back; only the letters I actually type myself come back). <cfform class="titleSearchForm" id="searchForm" action="search.cfm?GameID=#cfautosuggestvalue.GameID#" method="post"> <fieldset> <cfinput type="text" class="titleSearchField" name="TitleName" onChange="form.submit()" autosuggest="cfc:gz.cfcomp.search.AutoSuggestSearch({cfautosuggestvalue})"> <input type="button" class="titleSearchButton" value=" " /> </fieldset> </cfform> Query in CFC: <cfquery name="SearchResult" datasource="myDSN"> SELECT CONCAT(titles.TitleName, ' on ', platforms.PlatformAbbreviation) AS sResult, games.GameID FROM games Inner Join platforms ON games.PlatformID = platforms.PlatformID Inner Join titles ON titles.TitleID = games.TitleID WHERE UCase(titleName) LIKE Ucase('#ARGUMENTS.SearchString#%') ORDER BY titleName ASC; </cfquery> Two things: First of all, I would like to get the GameID back to the page making the AJAX request; I know why it is not coming back: Because I'm only returning sResult var, which does not include the GameID. Is there a way to return the GameID value without displaying it? The second thing: How to I grab a value from the auto-suggest once it is returned? Say I want to grab the GameID, or if I can't do that, the "TitleName" to use that in my query? I tried passing it to the form this way: action="search.cfm?GameID=#cfautosuggestvalue.GameID#" - but that does not work. How do I reference the autosuggestionvalue varaibles for use? Thanks

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• Entity Framework in layered architecture

  - by Kamyar

  I am using a layered architecture with the Entity Framework. Here's What I came up with till now (All the projects Except UI are class library): Entities: The POCO Entities. Completely persistence ignorant. No Reference to other projects. Generated by Microsoft's ADO.Net POCO Entity Generator. DAL: The EDMX (Entity Model) file with the context class. (t4 generated). References: Entities BLL: Business Logic Layer. Will implement repository pattern on this layer. References: Entities, DAL. This is where the objectcontext gets populated: var ctx=new DAL.MyDBEntities(); UI: The presentation layer: ASP.NET website. References: Entities, BLL + a connection string entry to entities in the config file (question #2). Now my three questions: Is my layer discintion approach correct? In my UI, I access BLL as follows: var customerRep = new BLL.CustomerRepository(); var Customer = customerRep.GetByID(myCustomerID); The problem is that I have to define the entities connection string in my UI's web.config/app.config otherwise I get a runtime exception. IS defining the entities connectionstring in UI spoils the layers' distinction? Or is it accesptible in a muli layered architecture. Should I take any additional steps to perform chage tracking, lazy loading, etc (by etc I mean the features that Entity Framework covers in a conventional, 1 project, non POCO code generation)? Thanks and apologies for the lengthy question.

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• Accessing a Class Member from a First-Class Function

  - by dbyrne

  I have a case class which takes a list of functions: case class A(q:Double, r:Double, s:Double, l:List[(Double)=>Double]) I have over 20 functions defined. Some of these functions have their own parameters, and some of them also use the q, r, and s values from the case class. Two examples are: def f1(w:Double) = (d:Double) => math.sin(d) * w def f2(w:Double, q:Double) = (d:Double) => d * q * w The problem is that I then need to reference q, r, and s twice when instantiating the case class: A(0.5, 1.0, 2.0, List(f1(3.0), f2(4.0, 0.5))) //0.5 is referenced twice I would like to be able to instantiate the class like this: A(0.5, 1.0, 2.0, List(f1(3.0), f2(4.0))) //f2 already knows about q! What is the best technique to accomplish this? Can I define my functions in a trait that the case class extends? EDIT: The real world application has 7 members, not 3. Only a small number of the functions need access to the members. Most of the functions don't care about them.

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• Loading enumerations from database

  - by Mosh

  Hello, I have a problem with mapping .NET enumerations to database tables. Imagine I have a table called Statuses with the following values: StatusID | Name 1 Draft 2 Ready ... ... In the application layer, I can either use a Repository to get all Statuses as an IList object. However, the problem with this approach is that I cannot reference a certain status in my business logic. For example, how can I implement something like this? if (myObject.Status is Ready) do this else if (myObject.Status is Draft) do that... Since the statuses are loaded dynamically, I cannot tell for sure what particular Status object in the List represents the Draft or Ready status. Alternatively, I could just use an enumeration like public enum Statuses { Draft, Ready }; Then I could easily use an enumeration in my business logic. if (myObject.Status == Statuses.Draft) // do something... However, the problem with this approach is that every time the user wants to modify the list of Statuses (adding a new status, or renaming an existing status) the application has to be re-compiled. We cannot load the statuses dynamically from the database. Has anyone else come across a similar situation? Any solutions/patterns? Cheers, Mosh

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• Using XPath on String in Android (JAVA)

  - by Rav

  I am looking for some examples of using xpath in Android? Or if anyone can share their experiences. I have been struggeling to make tail or head of this problem :-( I have a string that contains a standard xml file. I believe I need to convert that into an xml document. I have found this code which I think will do the trick: public static Document stringToDom(String xmlSource) throws SAXException, ParserConfigurationException, IOException { DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance(); DocumentBuilder builder = factory.newDocumentBuilder(); return builder.parse(new InputSource(new StringReader(xmlSource))); } Next steps Assuming the code above is OK, I need to apply xpath to get values from cat: "/animal/mammal/feline/cat" I look at the dev doc here: http://developer.android.com/reference/javax/xml/xpath/XPath.html and also look online, but I am not sure where to start! I have tried to use the following code: XPathFactory xPathFactory = XPathFactory.newInstance(); // To get an instance of the XPathFactory object itself. XPath xPath = xPathFactory.newXPath(); // Create an instance of XPath from the factory class. String expression = "SomeXPathExpression"; XPathExpression xPathExpression = xPath.compile(expression); // Compile the expression to get a XPathExpression object. Object result = xPathExpression.evaluate(xmlDocument); // Evaluate the expression against the XML Document to get the result. But I get "Cannot be resolved". Eclipse doesn't seem to be able to fix this import. I tried manually entering: javax.xml.xpath.XPath But this did not work. Does anyone know any good source code that I can utilise, for Android platform? 1.5

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• Getting auth token for dropbox account from accountmanager in android

  - by user1490880

  I am trying to get auth token for a dropbox account configured in device from account manager. I am using accountManager.getAuthToken(account, "DROPBOX",null,Hello.this, new GetAuthTokenCallback(), null);//account" is dropbox account I am seeing a Allow/Deny page. I click on Allow, but the callback is not getting invoked at all and i dont get the auth token. I got the authtoken for a google account with this(with a different authtokentype). What i am missing. I am not sure about the authTokenType parameter for dropbox. Also are there any other parameter specific for dropbox like the bundle parameter that i am missing. Is this way possible for dropbox? Check below for the function parameters public AccountManagerFuture<Bundle> getAuthToken (Account account, String authTokenType, Bundle options, Activity activity, AccountManagerCallback<Bundle> callback, Handler handler) Link: http://developer.android.com/reference/android/accounts/AccountManager.html UPDATE I assume since we are able to create a dropbox account in android Accounts and Sync(Settings), there must be a dropbox authenticator that has all the functions in AbstractAccountAuthenticator implemented including getAuthToken(). So dropbox should support giving auth token i think. Also dropbox uses oauth1, whereas account manager uses outh 2.0. So is this an issue.Can anyone comment on this?

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• In a bidirectional JPA OneToMany/ManyToOne association, what is meant by "the inverse side of the as

  - by Bytecode Ninja

  In these examples on TopLink JPA Annotation Reference: Example 1-59 @OneToMany - Customer Class With Generics @Entity public class Customer implements Serializable { ... @OneToMany(cascade=ALL, mappedBy="customer") public Set<Order> getOrders() { return orders; } ... } Example 1-60 @ManyToOne - Order Class With Generics @Entity public class Order implements Serializable { ... @ManyToOne @JoinColumn(name="CUST_ID", nullable=false) public Customer getCustomer() { return customer; } ... } It seams to me that the Customer entity is the owner of the association. However, in the explanation for the mappedBy attribute in the same document, it is written that: if the relationship is bidirectional, then set the mappedBy element on the inverse (non-owning) side of the association to the name of the field or property that owns the relationship as Example 1-60 shows. However, if I am not wrong, looks like in the example the mappedBy is actually specified on the owning side of the association, rather than the non-owning side. So my question is basically: In a bidirectional (one-to-many/many-to-one) association, which of the entities is the owner? How can we designate the One side as the owner? How can we designate the Many side as the owner? What is meant by "the inverse side of the association"? How can we designate the One side as the inverse? How can we designate the Many side as the inverse? Thanks in advance.

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