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  • ANTLR - Embedding Java code, evaluate before or after?

    - by wvd
    Hello all, I'm writing a simple scripting language on top of Java/JVM, where you can also embed Java code using the {} brackets. The problem is, how do I parse this in the grammar? I have two options: 1] Allow everything to be in it, such as: [a-z|a-Z|0-9|_|$], and go on 2] Get an extra java grammar and use that grammar to parse that small code (is it actually possible and efficient?) Since option 2] is basically a double-check since when evaluating java code it's also being checked. Now my last question is -- is way that can dynamically execute java code also with objects which have been created at runtime? Thanks, William van Doorn

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  • How created method with signature as List

    - by London
    Hi all, I'm very new to Java programming language so this is probably dumb question but I have to ask it because I can't figure it out on my own. Here is the deal. I want to create method which extracts certain object type from a list. So the method should receive List as argument, meaning list should contain either Object1 or Object2. I've tried like this : public Object1 extractObject(List<?>){ //some pseudo-code ... loop trough list and check if list item is instance of object one return that instance } The problem with declaring method with List<?> as method argument is that I receive compilation error from eclipse Syntax error on token ">", VariableDeclaratorId expected after this token. How do I set the method signature properly to accept object types either Object1 or Object2 ? Thank you

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  • Core Data and BOOL setup

    - by John Valen
    I am working on an app that uses Core Data as its backend for managing SQLite records. I have everything working with strings and numbers, but have just tried adding BOOL fields and can't seem to get things to work. In the .xcdatamodel, I have added a field to my object called isCurrentlyForSale which is not Optional, not Transient, and not Indexed. The attribute's type is set to Boolean with default value NO. When I created the class files from the data model, the boilerplate code added for this property in the .h header was: @property (nonatomic, retain) NSNumber * isCurrentlyForSale; along with the @dynamic isCurrentlyForSale; in the .m implementation file. I've always worked with booleans as simple BOOLs. I've read that I could use NSNumber's numberWithBool and boolValue methods, but this seems like an aweful lot of extra code for something so simple. Can the @property in the header be changed to a simple BOOL? If so is there anything to watch out for? Thanks -John

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  • Why prefix sql function names?

    - by AaronLS
    What is a scenario that exemplifies a good reason to use prefixes, such as fn_GetName, on function names in SQL Server? It would seem that it would be unnecessary since usually the context of its usage would make it clear that it's a function. I have not used any other language that has ever needed prefixes on functions, and I can't think of a good scenario that would show why SQL is any different. My only thinking is that perhaps in older IDE's it was useful for grouping functions together when the database objects were all listed together, but modern IDE's already make it clear what is a function.

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  • How do i connect with dart community to suggest something

    - by Muhammad Umer
    I am new to this stackoverflow and programming. So HI!!!! What i hope to do is tell something that i think is important to Dart community. If somehow it was possible to code android and or iphone apps using dart that would be very awesome and same for Dart.... There is one path, that is making program in dart compiling it to javascript and then making app using Adobe air..... .But looks inefficient. so is there any other way which i am unaware of, via which i can build an android app at least.. using dart i know you can build an app, using javascript..and css+html...so i am looking for html+css+dart. It'd be cool if adobe air supports dart language directly.

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  • why drawRect method is not being called?

    - by user338322
    #import <UIKit/UIKit.h> @interface quartzViewController : UIViewController { IBOutlet UIView *myView; } @end #import "quartzViewController.h" @implementation quartzViewController -(void)drawRect:(CGRect)rect { CGContextRef context = UIGraphicsGetCurrentContext(); CGContextSelectFont(context, "Arial", 24, kCGEncodingFontSpecific); CGContextSetTextPosition(context,80,80); CGContextShowText(context, "hello", 6); //not even this works CGContextShowTextAtPoint(context, 1,1, "hello", 6); } - (void)viewDidLoad { [myView setNeedsDisplay]; [super viewDidLoad]; } Will I have to make any changed in the nib? Thanks

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  • BindableAttribute, Combobox, Selectedvalue property - WinForms

    - by user63891
    I am deriving from combobox (WinForms) and am providing a new implementation for the Selectedvalue property. It works fine as is, but any change to the selectedvalue property is not updating other controls bound to the same "binding context" to change their values accordingly. I did try adding the BindableAttribute(true) to the property, but still it does nottrigger the change in value to the other linked controls. The control's DataBindings.add(...) is all set up. And other controls are also bound to the same data filed on the same datasource. Any ideas what i am doing wrong.

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  • Const parameter at constructor causes stackoverflow

    - by Luca
    I've found this strange behavior with VS2005 C++ compiler. Here is the situation: I cannot publish the code, but situation is very simple. Here is initial code: it work perfectly class Foo { public: Foo(Bar &bar) { ... } } The constructor implementation stores a reference, setup some members... indeed nothing special. If I change the code in the following way: class Foo { public: Foo(const Bar &bar) { ... } } I've added a const qualifier to the only constructor routine parameter. It compiles correctly, but the compiler outputs a warning saying that the routine Foo::Foo will cause a stackoverflow (even if the execution path doesn't construct any object Foo); effectively this happens. So, why the code without the const parameter works perfectly, while the one with the const qualifier causes a stackoverflow? What can cause this strange behavior?

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  • Hiding an internal interface in a "friend" assembly

    - by dmo
    I have two assemblies: A and B. A has InternalsVisibleTo set for B. I would like to make calls from A to get information that can only be known by a type defined in B in a way that keeps things internal. I can do this using an internal interface defined in A and implemented explicitly in B. Assembly A internal interface IHasData { Data GetData(); } class ClassA { DoSomething(IHasData); } Assembly B public abstract class ClassB : IHasData { Data IHasData.GetData() { /** do something internal **/ } } The trouble comes when someone references assembly B and derives from ClassB - they get the error: "The type 'AssemblyA.IHasData' is defined in an assembly that is not referenced" even though that type should be invisible to them. If I look at the public type definition I see what I expect - ClassB with no interfaces implemented. Why do I get this error? All of the implementation is in assembly B. I could use IHasData internally in ClassB and that wouldn't require assembly A to be referenced. Can someone help me understand what is going on?

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  • Caching the response of an ASP.NET HTTP Handler server and client side

    - by Bert Vandamme
    Is it possible to cache the response of a http handler on the server and on the client? This doesn't seem to be doing the trick: _context.Response.Cache.SetCacheability(HttpCacheability.Public); _context.Response.Cache.SetExpires(DateTime.Now.AddDays(7)); The _context is the HTTPContext passed as an argument to the ProcessRequest method on the IHttpHandler implementation. Any ideas? Update: The client does cache images that are loaded through the httphandler, but if another client does the same call, the server hasn't got it cached. So for each client that asks for the image, the server goes to the database (and filestream). If we use a aspx page instead of a httphandler together with a caching profile, then the images are cached both on the client and the server.

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  • I need to generate credit card surrogates (tokens) that are format preserving.

    - by jammer59
    For an eCommerce application I need to take a credit card and use the real card for passing through to a payment gateway but I need to store, and return to the transaction initiator, a surrogate that is format preserving. Specifically, this means: 1) The number of digits in the surrogate is the same as the real card number (PAN). 2) The issuer type part of the card -- the initial 1,2 or 4 digits remains the same in the surrogate as in the original PAN. 3) The final 4 digits of the surrogate remain the same (for customer service purposes.) 4) The surrogate passes the Luhn mod10 check for a syntactially valid credit card. I can readily handle requirements 1-3 but #4 has me completely stumped! The final implementation will be either t-sql or c#. Any ideas?

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  • What are these lines doing?

    - by Montecristo
    I'm starting learning javascript for a project, I've found a script that does a part of what I need to do, I'd like to know how it works, both for me and in case it needs to be modified. Originally it was used inside the page, now I've put it in a file on its own and does not work anymore, so I'm dividing it in parts, because I fail to get the whole thing. Here is what bother me most for now: 1) Is this a declaration a function? What is its name? How can it be invoked? (function() { //some code })(); 2) No clue of what is going on here var VARIABLE = VARIABLE || {}; 3) Am I defining a the implementation of methodCall here? Something like overriding a method in Java? VARIABLE.methodCall = function(parameter) { console.log("parameter was: " + parameter); }; Thank you in advance for your help.

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  • iPhone noob - different method types?

    - by codemonkey
    My apologies in advance for what is probably a really dumb question. I'm familiar (or at least getting familiar) with instance and class methods in objective-c, but have also seen method implementations that look like this: #import "Utilities.h" #import "CHAPPAppDelegate.h" #import "AppState.h" @implementation Utilities CHAPPAppDelegate* GetAppDelegate() { return (CHAPPAppDelegate *)[UIApplication sharedApplication].delegate; } AppState* GetAppState() { return [GetAppDelegate() appState]; } @end What are these? While I'm sure this is documented somewhere, I don't know what term to use in searching for an explanation of what's being done here. I like the syntax methods like this let me use when calling them, but I'm not sure exactly what I'm doing, what the implications are, how to send parameters to these types of functions, etc? To clarify how I ended up in this position, I started using these methods in a "utilities" class of mine after reading some online blog describing the author's preference for declaring these functions this way. Now I can't seem to track down a more detailed explanation of what exactly the differences are, etc.

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  • I'm new to C++. Please Help me with the Linked List (What functions to add)?

    - by Igal
    DEAR All; Hi, I'm just beginner to C++; Please help me to understand: What functions should be in the Linked list class ? I think there should be overloaded operators << and ; Please help me to improve the code (style, errors, etc,) Thanks for advance. Igal. Please review the small code for the integer List (enclosed MyNODE.h and ListDriver1.cpp); MyNODE.h // This is my first attempt to write linked list. Igal Spector, June 2010. #include <iostream.h> #include <assert.h> //Forward Declaration of the classes: class ListNode; class TheLinkedlist; // Definition of the node (WITH IMPLEMENTATION !!!, without test drive): class ListNode{ friend class TheLinkedlist; public: // constructor: ListNode(const int& value, ListNode *next= 0); // note: no destructor, as this handled by TheLinkedList class. // accessor: return data in the node. // int Show() const {return theData;} private: int theData; //the Data ListNode* theNext; //points to the next node in the list. }; //Implementations: //constructor: inline ListNode::ListNode(const int &value,ListNode *next) :theData(value),theNext(next){} //end of ListNode class, now for the LL class: class TheLinkedlist { public: //constructors: TheLinkedlist(); virtual ~TheLinkedlist(); // Accessors: void InsertAtFront(const &); void AppendAtBack(const &); // void InOrderInsert(const &); bool IsEmpty()const;//predicate function void Print() const; private: ListNode * Head; //pointer to first node ListNode * Tail; //pointer to last node. }; //Implementation: //Default constructor inline TheLinkedlist::TheLinkedlist():Head(0),Tail(0) {} //Destructor inline TheLinkedlist::~TheLinkedlist(){ if(!IsEmpty()){ //list is not empty cout<<"\n\tDestroying Nodes"<<endl; ListNode *currentPointer=Head, *tempPtr; while(currentPointer != 0){ //Delete remaining Nodes. tempPtr=currentPointer; cout<<"The node: "<<tempPtr->theData <<" is Destroyed."<<endl<<endl; currentPointer=currentPointer->theNext; delete tempPtr; } Head=Tail = 0; //don't forget this, as it may be checked one day. } } //Insert the Node to the beginning of the list: void TheLinkedlist::InsertAtFront(const int& value){ ListNode *newPtr = new ListNode(value,Head); assert(newPtr!=0); if(IsEmpty()) //list is empty Head = Tail = newPtr; else { //list is NOT empty newPtr->theNext = Head; Head = newPtr; } } //Insert the Node to the beginning of the list: void TheLinkedlist::AppendAtBack(const int& value){ ListNode *newPtr = new ListNode(value, NULL); assert(newPtr!=0); if(IsEmpty()) //list is empty Head = Tail = newPtr; else { //list is NOT empty Tail->theNext = newPtr; Tail = newPtr; } } //is the list empty? inline bool TheLinkedlist::IsEmpty() const { return (Head == 0); } // Display the contents of the list void TheLinkedlist::Print()const{ if ( IsEmpty() ){ cout << "\n\t The list is empty!!"<<endl; return; } ListNode *tempPTR = Head; cout<<"\n\t The List is: "; while ( tempPTR != 0 ){ cout<< tempPTR->theData <<" "; tempPTR = tempPTR->theNext; } cout<<endl<<endl; } ////////////////////////////////////// The test Driver: //Driver test for integer Linked List. #include <iostream.h> #include "MyNODE.h" // main Driver int main(){ cout<< "\n\t This is the test for integer LinkedList."<<endl; const int arraySize=11, ARRAY[arraySize]={44,77,88,99,11,2,22,204,50,58,12}; cout << "\n\tThe array is: "; //print the numbers. for (int i=0;i<arraySize; i++) cout<<ARRAY[i]<<", "; TheLinkedlist list; //declare the list for(int index=0;index<arraySize;index++) list.AppendAtBack( ARRAY[index] );//create the list cout<<endl<<endl; list.Print(); //print the list return 0; //end of the program. }

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  • Suggest resources for learning Scheme.

    - by EmFi
    I'll be starting a new job soon where Scheme is heavily used. I currently do not know Scheme, but my employer assures me that is not a problem. Regardless I'd like to hit the ground running and have a working knowledge of the language before my start date. So I'm looking for good resources from which to learn Scheme. I have had minimal exposure to functional languages. Really only a small chunk of a course devoted to Haskell. But I have a strong background in procedural and OO and procedural languages. Before it gets requested by a commenter, I am competent with the following languages: C, C++, C#, Java, Perl, Python, and Ruby.

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  • Proxy object references in MVC code

    - by krystan honour
    Hi there, I am just figuring out best practice with MVC now I have a project where we have chosen to use it in anger. My question is. If creating a list view which is bound to an IEnumerable is this bad practise? Would it be better to seperate the code generated by the WCF Service reference into a datastructure which essentially holds the same data but abstracts further from the service, meaning that the UI is totally unaware of the service implementation beneath. or do people just bind to the proxy object types and have done with it ? My personal feeling is to create an abstraction but this seems to violate the DRY principle.

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  • what is the wrong in this code(openAl in vc++)

    - by maiajam
    hi how are you all? i need your help i have this code #include <conio.h> #include <stdlib.h> #include <stdio.h> #include <al.h> #include <alc.h> #include <alut.h> #pragma comment(lib, "openal32.lib") #pragma comment(lib, "alut.lib") /* * These are OpenAL "names" (or "objects"). They store and id of a buffer * or a source object. Generally you would expect to see the implementation * use values that scale up from '1', but don't count on it. The spec does * not make this mandatory (as it is OpenGL). The id's can easily be memory * pointers as well. It will depend on the implementation. */ // Buffers to hold sound data. ALuint Buffer; // Sources are points of emitting sound. ALuint Source; /* * These are 3D cartesian vector coordinates. A structure or class would be * a more flexible of handling these, but for the sake of simplicity we will * just leave it as is. */ // Position of the source sound. ALfloat SourcePos[] = { 0.0, 0.0, 0.0 }; // Velocity of the source sound. ALfloat SourceVel[] = { 0.0, 0.0, 0.0 }; // Position of the Listener. ALfloat ListenerPos[] = { 0.0, 0.0, 0.0 }; // Velocity of the Listener. ALfloat ListenerVel[] = { 0.0, 0.0, 0.0 }; // Orientation of the Listener. (first 3 elements are "at", second 3 are "up") // Also note that these should be units of '1'. ALfloat ListenerOri[] = { 0.0, 0.0, -1.0, 0.0, 1.0, 0.0 }; /* * ALboolean LoadALData() * * This function will load our sample data from the disk using the Alut * utility and send the data into OpenAL as a buffer. A source is then * also created to play that buffer. */ ALboolean LoadALData() { // Variables to load into. ALenum format; ALsizei size; ALvoid* data; ALsizei freq; ALboolean loop; // Load wav data into a buffer. alGenBuffers(1, &Buffer); if(alGetError() != AL_NO_ERROR) return AL_FALSE; alutLoadWAVFile((ALbyte *)"C:\Users\Toshiba\Desktop\Graduation Project\OpenAL\open AL test\wavdata\FancyPants.wav", &format, &data, &size, &freq, &loop); alBufferData(Buffer, format, data, size, freq); alutUnloadWAV(format, data, size, freq); // Bind the buffer with the source. alGenSources(1, &Source); if(alGetError() != AL_NO_ERROR) return AL_FALSE; alSourcei (Source, AL_BUFFER, Buffer ); alSourcef (Source, AL_PITCH, 1.0 ); alSourcef (Source, AL_GAIN, 1.0 ); alSourcefv(Source, AL_POSITION, SourcePos); alSourcefv(Source, AL_VELOCITY, SourceVel); alSourcei (Source, AL_LOOPING, loop ); // Do another error check and return. if(alGetError() == AL_NO_ERROR) return AL_TRUE; return AL_FALSE; } /* * void SetListenerValues() * * We already defined certain values for the Listener, but we need * to tell OpenAL to use that data. This function does just that. */ void SetListenerValues() { alListenerfv(AL_POSITION, ListenerPos); alListenerfv(AL_VELOCITY, ListenerVel); alListenerfv(AL_ORIENTATION, ListenerOri); } /* * void KillALData() * * We have allocated memory for our buffers and sources which needs * to be returned to the system. This function frees that memory. */ void KillALData() { alDeleteBuffers(1, &Buffer); alDeleteSources(1, &Source); alutExit(); } int main(int argc, char *argv[]) { printf("MindCode's OpenAL Lesson 1: Single Static Source\n\n"); printf("Controls:\n"); printf("p) Play\n"); printf("s) Stop\n"); printf("h) Hold (pause)\n"); printf("q) Quit\n\n"); // Initialize OpenAL and clear the error bit. alutInit(NULL, 0); alGetError(); // Load the wav data. if(LoadALData() == AL_FALSE) { printf("Error loading data."); return 0; } SetListenerValues(); // Setup an exit procedure. atexit(KillALData); // Loop. ALubyte c = ' '; while(c != 'q') { c = getche(); switch(c) { // Pressing 'p' will begin playing the sample. case 'p': alSourcePlay(Source); break; // Pressing 's' will stop the sample from playing. case 's': alSourceStop(Source); break; // Pressing 'h' will pause the sample. case 'h': alSourcePause(Source); break; }; } return 0; } and it is run willbut i cant here any thing also i am new in programong and wont to program a virtual reality sound in my graduation project and start to learn opeal and vc++ but i dont how to start and from where i must begin and i want to ask if i need to learn about API win ?? and if i need how i can learn that thank you alote and i am sorry coz of my english

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  • How do Ruby and Python implement their interactive consoles?

    - by sxa
    When implementing the interpreter for my programming language I first thought of a simple console window which allows the user to enter some code which is then executed as a standalone program as a shell. But there are severe problems: If every line of code the user enters is handled as a standalone program, it has to go through the tokenizer and parser and is then just executed by the interpreter - what about functions then? How can the Python/Ruby interactive consoles (IDLE, irb) "share" the code? How is the code entered handled? Example: >> def x: >> print("Blah") >> >> x() Where is the function stored so it can be called at any time again? How can the interactive console take everything entered as obviously one program without executing everything over and over again?

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  • How do you write an idiomatic Scala Quicksort function?

    - by Don Mackenzie
    I recently answered a question with an attempt at writing a quicksort function in scala, I'd seen something like the code below written somewhere. def qsort(l: List[Int]): List[Int] = { l match { case Nil => Nil case pivot::tail => qsort(tail.filter(_ < pivot)) ::: pivot :: qsort(tail.filter(_ >= pivot)) } } My answer received some constructive criticism pointing out that List was a poor choice of collection for quicksort and secondly that the above wasn't tail recursive. I tried to re-write the above in a tail recursive manner but didn't have much luck. Is it possible to write a tail recursive quicksort? or, if not, how can it be done in a functional style? Also what can be done to maximise the efficiency of the implementation? Thanks in advance.

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  • Why does Windows 7 change encoding of characters in runtime?

    - by LukLed
    I have a delphi form: and my code: when I run this form in Windows 7, I see: In design time, form had polish letters in first label, but it doesn't have them in runtime. It looks ok on Vista or Windows XP. When I set caption of second label in code, everything works fine and characters are properly encoded. First 5 codes of top label on Windows 7: 65 97 69 101 83 First 5 codes of top label on Windows Vista/XP: 165 185 202 234 140 First 5 codes of bottom label on every system: 165 185 202 234 140 Windows 7 changes encoding, why? My system settings seem to be ok. I have proper language set for non-unicode applications in control panel.

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  • EF 4.x generated entity classes (POCO) and Map files

    - by JBeckton
    I have an MVC 4 app that I am working on and using the code first implementation except I cheated a bit and created my database first then generated my entity classes (poco) from my database using the EF power tools (reverse engineer). I guess you can say I did database first method but I have no edmx file just the context class and my entity classes (poco) I have a few projects in the works using MVC and EF with pocos but just the one project I used the tool to generate my pocos from the database. My question is about the mapping files that get created when I generate my pocos using the tool. What is the purpose of these Map files? I figured the map files are needed when generating the db from the model like with the true code first method, in my case where I am using a tool to generate my model from the database do the map files have any influence on how my app uses the entity classes?

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  • Java - how to tell class of an object?

    - by lkm
    Given a method that accepts as a parameter a certain supertype. Is there any way, within that method, to determine the actual class of the object that was passed to it? I.e. if a subtype of the allowable parameter was actually passed, is there a way to find out which type it is? If this isn't possible can someone explain why not (from a language design perspective)? Thanks Update: just to make sure I was clear void doSomething(MyType myType) { //determine if myType is MyType OR one of its subclasses } Since the method signature specifies the parameter as being MyType, then how can one tell if the object is actually a subtype of MyType (and which one).

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  • How to enable reading non-ascii characters in Servlets

    - by Daziplqa
    How to make the servlet accept non-ascii (Arabian, chines, etc) characters passed from JSPs? I've tried to add the following to top of JSPs: <%@page language="java" contentType="text/html; charset=UTF-8" pageEncoding="UTF-8"%> And to add the following in each post/get method in the servlet: request.setCharacterEncoding("UTF-8"); response.setCharacterEncoding("UTF-8"); I've tried to add a Filter that executes the above two statements instead of in the servlet. To be quite honest, these was working in the past, but now it doesn't work anymore. I am using tomcat 5.0.28/6.x.x on JDK1.6 on both Win & Linux boxes.

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  • Auto-complete/suggestion popup menu in GtkTextView

    - by Tyler
    I'm trying to create a system that will allow me to respond to the current text and auto-complete/suggest what should come next. For example if the user starts to type "Batm" then the system would respond with a menu showing the full completed word "Batman". Think of an IDE like Eclipse or Visual Studio and you get the idea. I understand how to create a popup menu in Gtk+ but what I don't understand is the following: How do I grab the word that the user is currently typing from a GtkTextView (or SourceView) so that I can do a lookup and offer suggestions? How do I position the menu in such a way that it sits next to the current text item (like it would in an IDE)? If anyone could offer suggestions or even a link to a tutorial or example on how to do this correctly I would be forever grateful. As always thanks for you help! Programming language: C

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  • Thread used for ServiceConnection callback (Android)

    - by Jannick
    Hi I'm developing an activity that binds to a local service (in onCreate of the activity): bindService(new Intent(this, CommandService.class), svcConn, BIND_AUTO_CREATE); I would like to be able to call methods through the IBinder in my lifecycle methods, but can not be sure that onServiceConnected have been called prior to these. I'm thinking of handling this by adding a queue of sorts in the ServiceConnection implementation, so that the method calls (Command pattern) will be executed once the connection is established. My questions are then: Is this stupid, any better ways? :) Are there any specification for which thread will be used to execute the ServiceConnection callbacks? More to the point, do I need to worry about synchronizing a queue datastructure? Edit - something like: public void onServiceConnected(ComponentName name, IBinder service) { dispatchService = (DispatchAsync)service; for(ExecutionTask task : queue){ dispatchService.execute(task.getCommand(), task); } }

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