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• 'WebException' error on back button even when calling 'void' async method

  - by BlazingFrog

  I have a windows phone app that allows the user to interact with it. Each interaction will always result in an async WCF call. In addition to that, some interactions will result in opening the browser, maps, email, etc... The problem is that, when hitting the back button, I sometime get the following error "An error (WebException) occurred while transmitting data over the HTTP channel." with the following stack trace: at System.ServiceModel.Channels.HttpChannelUtilities.ProcessGetResponseWebException(WebException webException, HttpWebRequest request, HttpAbortReason abortReason) at System.ServiceModel.Channels.HttpChannelFactory.HttpRequestChannel.HttpChannelAsyncRequest.CompleteGetResponse(IAsyncResult result) at System.ServiceModel.Channels.HttpChannelFactory.HttpRequestChannel.HttpChannelAsyncRequest.OnGetResponse(IAsyncResult result) at System.Net.Browser.ClientHttpWebRequest.<>c__DisplayClassa.<InvokeGetResponseCallback>b__8(Object state2) at System.Threading.ThreadPool.WorkItem.WaitCallback_Context(Object state) at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state) at System.Threading.ThreadPool.WorkItem.doWork(Object o) at System.Threading.Timer.ring() My understanding is that it's happening because my app opened another app (browser, maps, etc) before it had the time to execute the EndMyAsyncMethod(System.IAsyncResult result). Fair enough... What's really annoying is that it seems it should get fixed by cloning the server-side method, only making it void with the following operation contract [OperationContract(IsOneWay = true)] but I'm still getting the error. What's worse is that the exception is thrown in a system-generated part of the code and, thus, cannot be manually caught causing the app to just crash. I simply don't understand the need to execute an Endxxx method when it's explicitely marked as OneWay and void. EDIT I did find a similar issue here. It does seem that it is related to the message getting to the service (not the client callback). My next question is: if I'm now calling a method marked AsyncPattern and OneWay, what exactly should I be waiting for on the client to be sure the message was transmitted successfully? This is new service definition: [OperationContract(IsOneWay = true, AsyncPattern = true)] IAsyncResult BeginCacheQueryWithoutCallback(string param1, QueryInfoDataContract queryInfo, AsyncCallback cb, Object s); void EndCacheQueryWithoutCallback(IAsyncResult r); And the implementation: public IAsyncResult BeginCacheQueryWithoutCallback(string param1, QueryInfoDataContract queryInfo, AsyncCallback cb, Object s) { // do some stuff return new CompletedAsyncResult<string>(""); } public void EndCacheQueryWithoutCallback(IAsyncResult r) { }

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• BlackBerry Deployment Strategies

  - by cagreen

  I'm new to large scale BB app deployment and I'm looking for some clarification on the various methods of deployment. Please bear with me as I'm sure there is more to it than my naive view would lead me to believe. My app is very targeted to corporate users and requires a subscription to some additional services before it can be used. In other words, it's not targeted towards the consumer market, so I'm not worried about people not being able to easily find it online. What do I need to be aware of when looking at deployment strategies? Any gotchas? From my understanding my choices are: - App World small upfront vendor fee users can easily search for and find my app billing handled by RIM 4 licensing models (static, single, pool, dynamic). Though I'm not sure I've seen enough info on the pool and dynamic to fully appreciate how it might help me. - Download from my website billing is handled by me can I enforce the number of licenses that are in use within an organization? is this easier/harder for a user? - What else am I missing?

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• How do virtual destructors work?

  - by Prabhu

  Few hours back I was fiddling with a Memory Leak issue and it turned out that I really got some basic stuff about virtual destructors wrong! Let me put explain my class design. class Base { virtual push_elements() {} }; class Derived:public Base { vector<int> x; public: void push_elements(){ for(int i=0;i <5;i++) x.push_back(i); } }; void main() { Base* b = new Derived(); b->push_elements(); delete b; } The bounds checker tool reported a memory leak in the derived class vector. And I figured out that the destructor is not virtual and the derived class destructor is not called. And it surprisingly got fixed when I made the destructor virtual. Isn't the vector deallocated automatically even if the derived class destructor is not called? Is that a quirk in BoundsChecker tool or is my understanding of virtual destructor wrong?

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• Static Variables somehow maintaining state?

  - by gfoley

  I am working on an existing project, setup by another coder. I'm having some trouble understanding how state is being maintained between pages. There is a Class library which has some helper objects. Mostly these objects are just used for there static methods and rarely instantiated or inherited. This is an example class I'm testing with. public sealed class Application { public static string Test; } Now when i run something like the following in the base class of my page, I would expect the result to be "1: 2:Test" all the time (note that "1" is empty), but strangly its only this way the first time it is run. Then every time afterwards its "1:Test 2:Test". Somehow its maintaining the state of the static variable between pages and being refreshed?? Response.Write("1:" + SharedLibrary.Application.Test); SharedLibrary.Application.Test = "Test"; Response.Write(" 2:" + SharedLibrary.Application.Test); I need to create more classes like this, but want to understand why this is occurring in the first place. Many Thanks

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• How do you use FastInfoset with JAXWS?

  - by Chris Kessel

  I've got code that looks like it should be correct based on what I can find, but the spewed output doesn't indicate that it's using FastInfoset. My understanding is the Accept should indicate it can accept Fastinfoset and the response would actually use it, meaning it's not text/xml as the response type. Any idea what I'm doing wrong? I've scoured with Google and I'm having a hard time finding much detail on how to use FastInfoset at all. JaxWsProxyFactoryBean factory = new JaxWsProxyFactoryBean(); factory.getInInterceptors().add(new LoggingInInterceptor()); factory.getOutInterceptors().add(new LoggingOutInterceptor()); factory.setServiceClass( C360Server.class); factory.setAddress("http://localhost:8501/cxfcontroller/cl_v5"); C360Server client = (C360Server)factory.create(); ((BindingProvider)client).getRequestContext().put( "com.sun.xml.ws.client.ContentNegotiation", "optimistic"); C360Request requestTrans = new C360Request(); ... code to fill in the request ... C360Response response = client.findContacts( requestTrans ); The logging doesn't seem to indicate FastInfoset is even attempted though: INFO: Outbound Message --------------------------- ID: 1 Address: http://localhost:8501/cxfcontroller/cl_v5 Encoding: UTF-8 Content-Type: text/xml Headers: {SOAPAction=[""], Authorization=[Basic cWFfc3VwZXI6cWFfc3VwZXI=], Accept=[*/*]} Payload: <soap:Envelope xmlns:soap="http://schemas.xmlsoap.org/soap/envelope/"><soap:Body><ns1:findContacts>...bunch of xml deleted for brevity...</ns1:findContacts></soap:Body></soap:Envelope> -------------------------------------- May 17, 2010 3:23:45 PM org.apache.cxf.interceptor.LoggingInInterceptor logging INFO: Inbound Message ---------------------------- ID: 1 Response-Code: 200 Encoding: UTF-8 Content-Type: text/xml; charset=utf-8 Headers: {content-type=[text/xml; charset=utf-8], Content-Length=[611], Server=[Jetty(6.1.x)]} Payload: <soap:Envelope xmlns:soap="http://schemas.xmlsoap.org/soap/envelope/"><soap:Body><ns1:findContactsResponse>...bunch of xml spew deleted for brevity...</ns1:findContactsResponse></soap:Body></soap:Envelope> -------------------------------------- Any ideas what I'm doing wrong? Even if the server wasn't supporting FastInfoset, I still should see the attempted negotiation in the request, right?

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• MYSQL JOIN WHERE ISSUES - need some kind of if condition

  - by Breezer

  Hi Well this will be hard to explain but ill do my best The thing is i have 4 tables all with a specific column to relate to eachother. 1 table with users(agent_users) , 1 with working hours(agent_pers), 1 with sold items(agent_stat),1 with project(agent_pro) the user and the project table is irrelevant in the issue at hand but to give you a better understanding why certain tables is included in my query i decided to still mention them =) The thing is that I use 2 pages to insert data to the working hour and the sold items during that time tables, then i have a third page to summarize everything for current month, the query for that is as following: SELECT *, SUM(sv_p_kom),SUM(sv_p_gick),SUM(sv_p_lunch) FROM (( agent_users LEFT JOIN agent_pers ON agent_users.sv_aid = agent_pers.sv_p_uid) LEFT JOIN agent_stat ON agent_pers.sv_p_uid = agent_stat.sv_s_uid) LEFT JOIN agent_pro ON agent_pers.sv_p_pid=agent_pro.p_id WHERE MONTH(agent_pers.sv_p_datum) =7 GROUP BY sv_aname so the problem is now that i dont want sold items from previous months to get included in the data received, i know i could solve that by simple adding in the WHERE part MONTH(agent_stat.sv_s_datum) =7 but then if no items been sold that month no data at all will show up not the time or anything. Any aid on how i could solve this is greatly appreciated. if there's something that's not so clear dont hesitate to ask and ill try my best to answer. after all my english isn't the best out there :P regards breezer

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• Life Scope of Temporary Variable

  - by Yan Cheng CHEOK

  #include <cstdio> #include <string> void fun(const char* c) { printf("--> %s\n", c); } std::string get() { std::string str = "Hello World"; return str; } int main() { const char *cc = get().c_str(); // cc is not valid at this point. As it is pointing to // temporary string internal buffer, and the temporary string // has already been destroyed at this point. fun(cc); // But I am surprise this call will yield valid result. // It seems that the returned temporary string is valid within // scope (...) // What my understanding is, scope means {...} // Is this valid behavior guarantee by C++ standard? Or it depends // on your compiler vendor implementations? fun(get().c_str()); getchar(); } The output is : --> --> Hello World Hello, may I know the correct behavior is guarantee by C++ standard, or it depends on your compiler vendor implementations? I have tested this under VC2008 and VC6. Works fine for both.

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• Why doesn't the Java Collections API include a Graph implementation?

  - by dvanaria

  I’m currently learning the Java Collections API and feel I have a good understanding of the basics, but I’ve never understood why this standard API doesn’t include a Graph implementation. The three base classes are easily understandable (List, Set, and Map) and all their implementations in the API are mostly straightforward and consistent. Considering how often graphs come up as a potential way to model a given problem, this just doesn’t make sense to me (it’s possible it does exist in the API and I’m not looking in the right place of course). Steve Yegge suggests in one of his blog posts that a programmer should consider graphs first when attacking a problem, and if the problem domain doesn’t fit naturally into this data structure, only then consider the alternative structures. My first guess is that there is no universal way to represent graphs, or that their interfaces may not be generic enough for an API implementation to be useful? But if you strip down a graph to its basic components (vertices and a set of edges that connect some or all of the vertices) and consider the ways that graphs are commonly constructed (methods like addVertex(v) and insertEdge(v1, v2)) it seems that a generic Graph implementation would be possible and useful. Thanks for helping me understand this better.

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• Finding cause of memory leaks in large PHP stacks

  - by Mike B

  I have CLI script that runs over several thousand iterations between runs and it appears to have a memory leak. I'm using a tweaked version of Zend Framework with Smarty for view templating and each iteration uses several MB worth of code. The first run immediately uses nearly 8MB of memory (which is fine) but every following run adds about 80kb. My main loop looks like this (very simplified) $users = UsersModel::getUsers(); foreach($users as $user) { $obj = new doSomethingAwesome(); $obj->run($user); $obj = null; unset($obj); } The point is that everything in scope should be unset and the memory freed. My understanding is that PHP runs through its garbage collection process at it's own desire but it does so at the end of functions/methods/scripts. So something must be leaking memory inside doSomethingAwesome() but as I said it is a huge stack of code. Ideally, I would love to find some sort of tool that displayed all my variables no matter the scope at some point during execution. Some sort of symbol-table viewer for php. Does anything like that or any other tools that could help nail down memory leaks in php exist?

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• How to see external libraries code when debugging

  - by Sanva

  Hello!! First of all... this is my message #1 in this place, so... please be nice with me ;) I just started recently to study Gnome apps/libraries and I found that debuggers are an excellent way to learn, because seeing the code running helps a lot in understanding the structure of the program. But I have a problem. For example, debugging gnome-panel I found a lot of calls to external functions (basically the GTK+ functions), and although pretending to see all the code of all the functions applications like this call would be crazy, there are a lot that will be very interesting to see in action. The problem is that the debugger hasn't the code of those libraries loaded and it can't show it to me —at most it shows the line number where the execution is. I'm using Nemiver and when it tries to enter in an external function it claims because it can't find a file it supposed to be somewhere. For example, trying to enter in gtk_window_set_default_icon_name it tries to load /build/buildd/gtk+2.0-2.16.1/gtk/gtkwindow.c, and calling XSetIOErrorHandler, ../../src/ErrHndlr.c. So now I think that I'm doing something wrong... Why Nevimer are looking for those source files in those places?? My system does not even have the /build/buildd/ folders... and I don't know if I'm doing something wrong or I need to install somethig or what. Any suggestion? How do you debug this kind of applications? Best regards and thanks a lot for your time —and forgive me if my English is bad.

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• How to make write operation idempotent?

  - by Morgan Cheng

  I'm reading article about recently release Gizzard sharding framework by twitter(http://engineering.twitter.com/2010/04/introducing-gizzard-framework-for.html). It mentions that all write operations must be idempotent to make sure high reliability. According to wikipedia, "Idempotent operations are operations that can be applied multiple times without changing the result." But, IMHO, in Gazzard case, idempotent write operation should be operations that sequence doesn't matter. Now, my question is: How to make write operation idempotent? The only thing I can image is to have a version number attached to each write. For example, in blog system. Each blog must have a $blog_id and $content. In application level, we always write a blog content like this write($blog_id, $content, $version). The $version is determined to be unique in application level. So, if application first try to set one blog to "Hello world" and second want it to be "Goodbye", the write is idempotent. We have such two write operations: write($blog_id, "Hello world", 1); write($blog_id, "Goodbye", 2); These two operations are supposed to changed two different records in DB. So, no matter how many times and what sequence these two operations executed, the results are same. This is just my understanding. Please correct me if I'm wrong.

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• DDD: Enum like entities

  - by Chris

  Hi all, I have the following DB model: **Person table** ID | Name | StateId ------------------------------ 1 Joe 1 2 Peter 1 3 John 2 **State table** ID | Desc ------------------------------ 1 Working 2 Vacation and domain model would be (simplified): public class Person { public int Id { get; } public string Name { get; set; } public State State { get; set; } } public class State { private int id; public string Name { get; set; } } The state might be used in the domain logic e.g.: if(person.State == State.Working) // some logic So from my understanding, the State acts like a value object which is used for domain logic checks. But it also needs to be present in the DB model to represent a clean ERM. So state might be extended to: public class State { private int id; public string Name { get; set; } public static State New {get {return new State([hardCodedIdHere?], [hardCodeNameHere?]);}} } But using this approach the name of the state would be hardcoded into the domain. Do you know what I mean? Is there a standard approach for such a thing? From my point of view what I am trying to do is using an object (which is persisted from the ERM design perspective) as a sort of value object within my domain. What do you think? Question update: Probably my question wasn't clear enough. What I need to know is, how I would use an entity (like the State example) that is stored in a database within my domain logic. To avoid things like: if(person.State.Id == State.Working.Id) // some logic or if(person.State.Id == WORKING_ID) // some logic

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• Should I use a regular server instead of AWS?

  - by Jon Ramvi

  Reading about and using the Amazon Web Services, I'm not really able to grasp how to use it correctly. Sorry about the long question: I have a EC2 instance which mostly does the work of a web server (apache for file sharing and Tomcat with Play Framework for the web app). As it's a web server, the instance is running 24/7. It just came to my attention that the data on the EC2 instance is non persistent. This means I lose my database and files if it's stopped. But I guess it also means my server settings and installed applications are lost as they are just files in the same way as the other data. This means that I will either have to rewrite the whole app to use amazon CloudDB or write some code which stores the db on S3 and make my own AMI with the correct applications installed and configured. Or can this be quick-fixed by using EBS somehow? My question is 1. is my understanding of aws is correct? and 2. is it's worth it? It could be a possibility to just set up a regular dedicated server where everything is persistent, as you would expect. Would love to have the scaleability of aws though..

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• Are .NET's regular expressions Turing complete?

  - by Robert

  Regular expressions are often pointed to as the classical example of a language that is not Turning complete. For example "regular expressions" is given in as the answer to this SO question looking for languages that are not Turing complete. In my, perhaps somewhat basic, understanding of the notion of Turning completeness, this means that regular expressions cannot be used check for patterns that are "balanced". Balanced meaning have an equal number of opening characters as closing characters. This is because to do this would require you to have some kind of state, to allow you to match the opening and closing characters. However the .NET implementation of regular expressions introduces the notion of a balanced group. This construct is designed to let you backtrack and see if a previous group was matched. This means that a .NET regular expressions: ^(?<p>a)*(?<-p>b)*(?(p)(?!))$ Could match a pattern that: ab aabb aaabbb aaaabbbb ... etc. ... Does this means .NET's regular expressions are Turing complete? Or are there other things that are missing that would be required for the language to be Turing complete?

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• How can I help fellow students struggling in programming classes?

  - by David Barry

  I'm a computer science student finishing up my second semester of programming classes. I've enjoyed them quite a bit, and learned a lot, but it seems other students are struggling with the concepts and assignments more than I am. When an assignment is due, the inevitable group email comes out the day or two before with people needing some help either with a specific part of the problem, or sometimes people just seem to have a hard time knowing where to start. I'd really like to be able to help out, but I have a hard time thinking of the right way to give them help without giving them the answer. When I'm having trouble understanding a concept, a code snippet can go along way to helping me, but at the same time if it makes a lot of sense, it can be difficult to think of another way to go about it. Plus the Academic Integrity section of each assignment is always looming overhead warning against sharing code with others. I've tried using pseudo code to help give others an idea on program flow, leaving them to figure out how to implement certain aspects of it, but I didn't get too much feedback and don't know how much it actually helped them out, or if it just confused them further. So I'm basically looking to see if anyone has experience with this, or good ways that I can help out other students to nudge them in the right direction or help them think about the problem in the right way.

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• Explanation of `self` usage during dealloc?

  - by Greg

  I'm trying to lock down my understanding of proper memory management within Objective-C. I've gotten into the habit of explicitly declaring self.myProperty rather than just myProperty because I was encountering occasional scenarios where a property would not be set to the reference that I intended. Now, I'm reading Apple documentation on releasing IBOutlets, and they say that all outlets should be set to nil during dealloc. So, I put this in place as follows and experienced crashes as a result: - (void)dealloc { [self.dataModel close]; [self.dataModel release], self.dataModel = nil; [super dealloc]; } So, I tried taking out the "self" references, like so: - (void)dealloc { [dataModel close]; [dataModel release], dataModel = nil; [super dealloc]; } This second system seems to work as expected. However, it has me a bit confused. Why would self cause a crash in that case, when I thought self was a fairly benign reference more used as a formality than anything else? Also, if self is not appropriate in this case, then I have to ask: when should you include self references, and when should you not?

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• Why does instanceof seem to work in a static generic function sometimes?

  - by michael

  Greetings. This is my first post in this site. I thought that because of type erasure, one could not expect the following code to compile, and indeed, it did not compile on an earlier version of Eclipse. My understanding was that instanceof was a run-time operator and could not know about the generic type which would be, by run-time, compiled away: public static <E extends Comparable<? super E>> void SampleForQuestion(E e) { if ( !(e instanceof String) ) System.out.println("I am not a String"); else System.out.println("I am a String"); } However, I was surprised to see that one of your threads actually included some code like this in an answer, and my latest Eclipse (Galileo on Windows with JVM 1.6 rev 20) is perfectly happy with it -- and it works, too. (I did notice that someone said it worked on Eclipse but not in another IDE/JDK in that thread, but don't remember the specifics.) Can someone explain why it works, and more importantly, because I have to guide my students, whether it should be expected to work in the future. Thank you. (I hope the code formatting comes through correctly - it looks indented correctly from my perspective and there are no tabs.)

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• How do I loop through elements inside a div?

  - by crosenblum

  I have to make a custom function for search/replace text, because firefox counts text nodes differently than IE, Google Chrome, etc.. I am trying to use this code, that I saw at Firefox WhiteSpace Issue since in my other function, I am looping numerically through nodes, which serves my functional needs perfectly, in other browsers. But refuses to work, as part of a search/replace function that takes place after some ajax content is loaded. Here is the code, that I have tried to get to work, but I must be missing the correct understanding of the context of how to loop thru elements inside a div. // get all childnodes inside div function div_translate(divid) { // list child nodes of parent if (divid != null) { // var children = parent.childNodes, child; var parentNode = divid; // start loop thru child nodes for(var node=parentNode.firstChild;node!=null;node=node.nextSibling){ // begin check nodeType if(node.nodeType == 1){ // get value of this node var value = content(node); // get class of this node var myclass = node.attr('class'); console.log(myclass); // begin check if value undefined if (typeof(value) != 'undefined' && value != null) { console.log(value); // it is a text node. do magic. for (var x = en_count; x > 0; x--) { // get current english phrase var from = en_lang[x]; // get current other language phrase var to = other_lang[x]; if (value.match(from)) { content(node, value.replace(from, to)); } } } // end check if value undefined } // end check nodeType } // end loop thru child nodes } }

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• How do i select all text nodes using XSL?

  - by user323719

  I want to get the generate-id(.) of all the text nodes after node and before node . I am looking for some generic XSL and not tightly coupled to the sample input pattern mentioned below. For any input pattern i want to get the ids of all the text nodes between node and . Sample input for better understanding: <a> <b> <c> This is first text node </c> </b> <d> <e> This is my second text node </e> <f> This is my <m/>third text node </f> <g> One more text node </g> <h> <i> This is my fourth text node </i> </h> <j> This is my fifth <n/>text node </j> <k> <l> This is my sixth text node </l> </k> </d> </a> Expected output: Generate id of the text nodes with values "third text node ", "One more text node", "This is my fourth text node", "This is my fifth" which lie inbetween nodes <m/> and <n/> Please give your ideas.

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• Copy constructor called even when returning by reference?

  - by Johnyy

  Hi, I am testing the return of local objects by reference. My original test went well but something else happens unexpected. #include <iostream> using namespace std; class MyInt { public: MyInt(int i){ value = new int(i); } ~MyInt(){ delete value; } int getValue(){ return *value; } MyInt(const MyInt &b){ cout<<"Copy"<<endl; } private: int* value; }; MyInt& returnref(){ MyInt a(10); cout<<"Returning from returnref()"<<endl; return a; } int main(){ MyInt a = returnref(); cout<<a.getValue()<<endl; return 0; } My console prints "Returning from ..." then "Copy" then a random value. My understanding of pass by reference is that it does not need to make any copy. Why is it not doing what I expected?

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• Strange behaviour of NSScanner on simple whitespace removal

  - by Michael Waterfall

  I'm trying to replace all multiple whitespace in some text with a single space. This should be a very simple task, however for some reason it's returning a different result than expected. I've read the docs on the NSScanner and it seems like it's not working properly! NSScanner *scanner = [[NSScanner alloc] initWithString:@"This is a test of NSScanner !"]; NSMutableString *result = [[NSMutableString alloc] init]; NSString *temp; NSCharacterSet *whitespace = [NSCharacterSet whitespaceCharacterSet]; while (![scanner isAtEnd]) { // Scan upto and stop before any whitespace [scanner scanUpToCharactersFromSet:whitespace intoString:&temp]; // Add all non whotespace characters to string [result appendString:temp]; // Scan past all whitespace and replace with a single space if ([scanner scanCharactersFromSet:whitespace intoString:NULL]) { [result appendString:@" "]; } } But for some reason the result is @"ThisisatestofNSScanner!" instead of @"This is a test of NSScanner !". If you read through the comments and what each line should achieve it seems simple enough!? scanUpToCharactersFromSet should stop the scanner just as it encounters whitespace. scanCharactersFromSet should then progress the scanner past the whitespace up to the non-whitespace characters. And then the loop continues to the end. What am I missing or not understanding?

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• multiple clients - one server connection with sockets tcp/ip c# .net

  - by jagse

  Hello guys, I need to develop a client server system where I can have multiple clients communicating with one server at the same time. I want to communicate xml serialized objects and also need to send and receive other commands to invoke methods. Now, I am just starting with socket programming in C# and .Net and found that the asynchronous I/O is the way to go so that the methods dont block the execution of code. Also there are many examples of how to make a simple client server system. So I have a basic understanding of how that works. Anyway, what still is not clear to me is how I can set up a server which can manage connections to multiple clients? Can I just create a new socket per connection and then store those in some kind of list? Do I need some kind of multiplexing to achieve this? Do I have to listen at multiple ports? What`s the best way here? And the other thing is if I need to develop my own protocol to differentiate between what I am actually sending over the network -- xml serialized object or a command which might be just a string encoded in ascII or something. Or would I develop my own protocol just to send these commands? Any kind of help is apreciated! If someone knows a good book which covers this sort of stuff, let me know. Cheers I forgot to mention that some of my clients which are supposed to communicate with my server will be pda and I therefore use the compact framework... So this might bring in some restrictions...

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• Why is BorderLayout calling setSize() and setBounds()?

  - by ags

  I'm trying to get my head around proper use of the different LayoutManagers to make my GUI design skills more efficient and effective. For me, that usually requires a detailed understanding of what is going on under the hood. I've found some good discussion of the interaction and consequences of a Container using BorderLayout containing a Container using FlowLayout. I understand it for the most part, but wanted to confirm my mental model and to do so I am looking at the code for BorderLayout. In the code snippet below taken from BorderLayout.layoutContainer(), note the calls to the child Component's setSize() method followed by setBounds(). Looking at the source for these methods of Component, setSize() actually calls setBounds() with the current values for Component.x and Component.y. Why is this done (and not entirely redudant?) Doesn't the setBounds() call completely overwrite the results of the setSize() call? if ((c=getChild(NORTH,ltr)) != null) { c.setSize(right - left, c.height); Dimension d = c.getPreferredSize(); c.setBounds(left, top, right - left, d.height); top += d.height + vgap; } I'm also tring to understand where/when the child Component's size is initially set (before the LayoutManager.layoutContainer() method is called). Finally, this post itself raises a "meta-question": in a situation like this, where the source is available elsewhere, is the accepteed protocol to include the entire method? Or some other way to make it easier for folks to participate in the thread? Thanks.

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• Android SDK not recognizing debug-able device.

  - by kal.zekdor

  I'm new to Android development, and am attempting to run a test application on my actual device. I followed the instructions at http://developer.android.com/guide/developing/device.html (and related links), but the Android Debug Bridge (adb) doesn't recognize my connected device. Some quick background info, I'm running WinXP, developing with Eclipse, with a Motorola Droid running Android 2.1 as my physical device. An overview of the steps I've taken: Installed the Android SDK, downloading all necessary packages. Enabled USB Debugging on my device. Connected Device via USB, installing the driver from the SDK folder. I'll stop here (though I continued to setup my application to be debug-able in Eclipse), because I at this point I noticed a problem. Running "sdk\tools\adb devices" at this point (at least, by my understanding), should list my device as connected. However, running this yields only: List of devices attached My device recognizes that it's connected to a computer in debug mode, and my computer recognizes the device. However, I can't seem to get the sdk to recognize it. I'll leave out the steps I used to setup Eclipse for debugging on a device, as it doesn't seem relevant to the problem. I'll include them if requested. If anyone has any ideas, I'd greatly appreciate some assistance. Thanks in advance for your time.

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• How do I create a simple Windows form to access a SQL Server database?

  - by NoCatharsis

  I believe this is a very novice question, and if I'm using the wrong forum to ask, please advise. I have a basic understanding of databasing with MS SQL Server, and programming with C++ and C#. I'm trying to teach myself more by setting up my own database with MS SQL Server Express 2008 R2 and accessing it via Windows forms created in C# Express 2010. At this point, I just want to keep it to free or Express dev tools (not necessarily Microsoft though). Anyway, I created a database using the instructions provided here and I set the data types appropriately for each column (no errors in setup at least). Now I'm designing the GUI in C# Express but I've kind of hit a wall as far as the database connection. Is there a simple way to access the database I created locally using C# Express? Can anyone suggest a guide that has all this spelled out already? I am a self-learner so I look forward to teaching myself how to use these applications, but any pointers to start me off in the right direction would be greatly appreciated.

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