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  • Gridview looses ItemTemplate after columns are removed

    - by Middletone
    I'm trying to bind a datatable to a gridview where I've removed some of the autogenerated columns in the code behind. I've got two template columns and it seems that when I alter the gridview in code behind and remove the non-templated columns that the templates loose the controls that are in them. Using the following as a sample, "Header A" will continue to be visible but "Header B" will dissapear after removing any columsn that are located at index 2 and above. I'm creating columns in my codebehind for the grid as a part of a reporting tool. If I don't remove the columns then there doesn't seem to be an issue. <asp:GridView ID="DataGrid1" runat="server" AutoGenerateColumns="false" AllowPaging="True" PageSize="10" GridLines="Horizontal"> <Columns> <asp:TemplateField HeaderText="Header A" > <ItemTemplate > Text A </ItemTemplate> </asp:TemplateField> <asp:TemplateField> <HeaderTemplate> Header B </HeaderTemplate> <ItemTemplate> Text B </ItemTemplate> </asp:TemplateField> </Columns> </asp:GridView> For i = 2 To DataGrid1.Columns.Count - 1 DataGrid1.Columns.RemoveAt(2) Next EDIT So from what I've read this seems to be a problem that occurs when the grid is altered. Does anyone know of a good workaround to re-initialize the template columns or set them up again so that when the non-template columns are removed that hte templates don't get removed as well?

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  • Testing When Correctness is Poorly Defined?

    - by dsimcha
    I generally try to use unit tests for any code that has easily defined correct behavior given some reasonably small, well-defined set of inputs. This works quite well for catching bugs, and I do it all the time in my personal library of generic functions. However, a lot of the code I write is data mining code that basically looks for significant patterns in large datasets. Correct behavior in this case is often not well defined and depends on a lot of different inputs in ways that are not easy for a human to predict (i.e. the math can't reasonably be done by hand, which is why I'm using a computer to solve the problem in the first place). These inputs can be very complex, to the point where coming up with a reasonable test case is near impossible. Identifying the edge cases that are worth testing is extremely difficult. Sometimes the algorithm isn't even deterministic. Usually, I do the best I can by using asserts for sanity checks and creating a small toy test case with a known pattern and informally seeing if the answer at least "looks reasonable", without it necessarily being objectively correct. Is there any better way to test these kinds of cases?

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  • Most efficient way of checking if Date object and Calendar object are in the same month

    - by Indigenuity
    I am working on a project that will run many thousands of comparisons between dates to see if they are in the same month, and I am wondering what the most efficient way of doing it would be. This isn't exactly what my code looks like, but here's the gist: List<Date> dates = getABunchOfDates(); Calendar month = Calendar.getInstance(); for(int i = 0; i < numMonths; i++) { for(Date date : dates) { if(sameMonth(month, date) .. doSomething } month.add(Calendar.MONTH, -1); } Creating a new Calendar object for every date seems like a pretty hefty overhead when this comparison will happen thousands of times, soI kind of want to cheat a bit and use the deprecated method Date.getMonth() and Date.getYear() public static boolean sameMonth(Calendar month, Date date) { return month.get(Calendar.YEAR) == date.getYear() && month.get(Calendar.MONTH) == date.getMonth(); } I'm pretty close to just using this method, since it seems to be the fastest, but is there a faster way? And is this a foolish way, since the Date methods are deprecated? Note: This project will always run with Java 7

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  • Problem with passing vector of pointers to objects to member function of another object

    - by Jamesz
    Hi, I have a vector of pointers to Mouse objects called 'mice'. I'm passing the mice to the cat by reference. vector <Mouse*> mice; Cat * c; c->lookForMouse(&mice); And here's my lookForMouse() member function void Cat::lookForMouse(vector <Mouse*> *mice) { ... } And now to the problem! Within the function above, I can't seem to access my mice. This below will not work mice[i]->isActive(); The error message I receive suggests to use mice[i].isActive(), but this throws an error saying isActive() is not a member of std::vector<_Ty ... This works though... vector <Mouse*> miceCopy = *mice; miceCopy[i]->isActive(); I understand that I shouldn't be creating another vector of mice here, it defeats the whole point of passing it by reference (let me know if I'm wrong)... Why can't I do mice[i]-isActive() What should I be doing? Thanks for your time and help :D James.

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  • HashMap Memory Leak because of Dynamic Array

    - by Jake M
    I am attempting to create my own HashMap to understand how they work. I am using an array of Linked Lists to store the values(strings) in my hashmap. I am creating the array like this: Node** list; Instead of this: Node* list[nSize]; This is so the array can be any size at runtime. But I think I am getting a memory leak because of how I am doing this. I dont know where the error is but when I run the following simple code the .exe crashes. Why is my application crashing and how can I fix it? Note: I am aware that using a vector would be much better than an array but this is just for learning and I want to challenge myself to create the hashmap using a 'Dynamic' Array. PS: is that the correct term(Dynamic Array) for the kind of array I am using? struct Node { // to implement }; class HashMap { public: HashMap(int dynSize) { *list = new Node[dynSize]; size = dynSize; for (int i=0; i<size; i++) list[i] = NULL; cout << "END\n"; } ~HashMap() { for (int i=0; i<size; i++) delete list[i]; } private: Node** list; // I could use a vector here but I am experimenting with a pointer to an array(pointer), also its more elegant int size; }; int main() { // When I run this application it crashes. Where is my memory leak? HashMap h(5); system("PAUSE"); return 0; }

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  • PHP mail may be filtered out by spam?

    - by Derek
    I am creating a small company, and would like to send out emails to my clients once they have signed up for my service to activate their accounts. I am currently using PHP's mail() function, however I am worried that my emails are being filtered out by spam filters. Is there a better way to go about this? $email = 'XZY Client Email address @ somedomain.com'; $emailSubject = "Welcome to XYZ Service!"; $to = $email; $subject .= "".$emailSubject.""; $headers .= "From: [email protected]\r\n" . "X-Mailer: php"; $headers .= "MIME-Version: 1.0\r\n"; $headers .= "Content-Type: text/html; charset=ISO-8859-1\r\n"; $message = "<html><body>"; $message .= "Welcome to XYZ Service! \n Activate your account by clicking the following link: link..."; mail($to, $subject, $message, $headers); Is there a way to authenticate these emails so that my clients know that they are from my actual service? Thank you in advance!

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  • How can I limit asp.net control actions based on user role?

    - by Duke
    I have several pages or views in my application which are essentially the same for both authenticated users and anonymous users. I'd like to limit the insert/update/delete actions in formviews and gridviews to authenticated users only, and allow read access for both authed and anon users. I'm using the asp.net configuration system for handling authentication and roles. This system limits access based on path so I've been creating duplicate pages for authed and anon paths. The solution that comes to mind immediately is to check roles in the appropriate event handlers, limiting what possible actions are displayed (insert/update/delete buttons) and also limiting what actions are performed (for users that may know how to perform an action in the absence of a button.) However, this solution doesn't eliminate duplication - I'd be duplicating security code on a series of pages rather than duplicating pages and limiting access based on path; the latter would be significantly less complicated. I could always build some controls that offered role-based configuration, but I don't think I have time for that kind of commitment right now. Is there a relatively easy way to do this (do such controls exist?) or should I just stick to path-based access and duplicate pages? Does it even make sense to use two methods of authorization? There are still some pages which are strictly for either role so I'll be making use of path-based authorization anyway. Finally, would using something other than path-based authorization be contrary to typical asp.net design practices, at least in the context of using the asp.net configuration system?

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  • How can I stop the iPhone from displaying a transform change until after the screen is redrawn

    - by Ed Marty
    I have found the UIScrollView's zooming mechanism to be clunk and essentially unusable. So instead, I'm rolling my own. I have a UIView that resizes itself with the pinch-zoom, and that's working fine. When the zoom is complete, the view needs to reset its transform and redraw the images. The zoom works essentially in the same way the UIScrollView does. It sets the transform property of the UIView until complete. Then, when the zoom finishes, I want to reset the transform to CGAffineTransformIdentity, resize the frame to be the size it was before, and tell the view to redraw itself at the new size. It all works pretty well, except when I change the transform to identity then redraw the image, there is a slight flicker before the image completely redraws. This is due to the fact that I'm using a subclass of CATiledLayer, since the view can be of arbitrary size. I've overridden the fadeDuration to be zero, but there is still a flicker while the transform is reset before the redraw is finished. Is there any simple way to overcome this without creating another view to draw with then replacing it?

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  • how to create class alert using lcdui package in blackberry

    - by Baby
    Advance Thanks.i am new to blackberry developement.i try the following code for creating alert using lcdui package.but nothing will coming when i am running Plz help me. package alertpack; import javax.microedition.lcdui.Alert; import javax.microedition.lcdui.AlertType; import javax.microedition.lcdui.Command; import javax.microedition.lcdui.CommandListener; import javax.microedition.lcdui.Display; import javax.microedition.lcdui.Displayable; import javax.microedition.lcdui.Form; import javax.microedition.lcdui.Screen; import javax.microedition.midlet.MIDlet; import javax.microedition.midlet.MIDletStateChangeException; import net.rim.device.api.ui.Color; import net.rim.device.api.ui.Graphics; public class alertclass extends MIDlet implements CommandListener { private Display display; private Alert alert; private Form form = new Form("Throw Exception"); private Command exit = new Command("Exit", Command.SCREEN, 1); //public static void main(String[] args) //{ //} private boolean exitFlag = false; public alertclass(){ display = Display.getDisplay(this); form.addCommand(exit); form.setCommandListener(this); } protected void destroyApp(boolean unconditional) throws MIDletStateChangeException { // TODO Auto-generated method stub if (unconditional == false) { throw new MIDletStateChangeException(); } } protected void pauseApp() { // TODO Auto-generated method stub } protected void startApp() throws MIDletStateChangeException { // TODO Auto-generated method stub display.setCurrent(form); } public void commandAction(Command c, Displayable d) { // TODO Auto-generated method stub if (c == exit) { try { if (exitFlag == false) { alert = new Alert("Busy", "Please try again.", null, AlertType.WARNING); alert.setTimeout(Alert.FOREVER); display.setCurrent(alert, form); destroyApp(false); } else { destroyApp(true); notifyDestroyed(); } } catch (Exception exception) { exitFlag = true; } } } }

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  • BinaryFormatter in C# a good way to read files?

    - by mr-pac
    I want to read a binary file which was created outside of my program. One obvious way in C# to read a binary file is to define class representing the file and then use a BinaryReader and read from the file via the Read* methods and assign the return values to the class properties. What I don't like with the approach is that I manually have to write code that reads the file, although the defined structure represents how the file is stored. I also have to keep the order correct when I read. After looking a bit around I came across the BinaryFormatter which can automatically serialize and deserialze object in binary format. One great advantage would be that I can read and also write the file without creating additional code. However I wonder if this approach is good for files created from other programs on not just serialized .NET objects. Take for example a graphics format file like BMP. Would it be a good idea to read the file with a BinaryFormatter or is it better to manually and write via BinaryReader and BinaryWriter? Or are there any other approaches which suit better? I'am not looking for concrete examples but just for an advice what is the best way to implement that.

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  • XML File as Excel file.

    - by FrustratedWithFormsDesigner
    I have a number of reports that I run against my database that need to eventually go to the end-users as Excel spreadsheets. Initially, I was creating text reports, but the steps to convert the text to a spreadsheet were a bit cumbersome. There were too many steps to import text to the spreadsheet, and multi-line text rows were imported as individual rows in Excel (which was incorrect). Currently, I am generating simple XML saving the file with an ".xls" extension. This works better, but there is still the problem of Excel prompting the user with an XML import dialogue every time they open the file, and then having to save a new file if they add notes or change the layout to the file (which they almost certainly will be doing). Sample "xls" file: <?xml version="1.0" standalone="yes"?> <report_rows> <row> <NAME>Test Data</NAME> <COUNT>345</COUNT> </row> <!-- many more row elements... --> </report_rows> Is there any way to add markup to the file to hint to Excel how it should import and handle the file? Ideally, the end user should be able to open and save the file like any othe spreadsheet they create directly from Excel. Is this even possible? UPDATE: We are running Office 2003 here. UPDATE: The XML is generated from a sqlplus script, no option to use C#/.NET here.

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  • Licensing for the undecided

    - by Jasper
    I am creating a game in C++. Now I am not sure on how I will distribute it yet - though I am pretty sure that I won't be asking money for it. And I am looking into a licensing and I wondered if there is a license that is suited for the undecided like me. My current releases (which are really really early versions of the game, with far from full functionality) are executable only. However, I am actually thinking that I might release the source on an open source license. For now, I am the only contributor, so that would be no problem as I only need my own permission to move to a less restrictive license. However, when I allow other people to contribute, I would need all their permissions to do so (right?). So I was wondering if there is a license that let's me distribute the game executable only for now, but will let me switch to a less restrictive license if I want. Basically I need a license in which contributors give permission to switch to a less restrictive license up front. Does anybody know of license (or other construction) that would allow me to do so?

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  • Export sheet from Excel to CSV

    - by Mike Wills
    I am creating a spread sheet to help ease the entry of data into one of our systems. They are entering inventory items into this spread sheet to calculate the unit cost of the item (item cost + tax + S&H). The software we purchased cannot do this. Aan invoice can have one or more lines (duh!) and I calculate the final unit cost. This is working fine. I then want to take that data and create a CSV from that so they can load it into our inventory system. I currently have a second tab that is laid out like I want the CSV, and I do an equal cell (=Sheet!A3) to get the values on the "export sheet". The problem is when they save this to a CSV, there are many blank lines that need to be deleted before they can upload it. I want a file that only contains the data that is needed. I am sure this could be done in VBA, but I don't know where to start or know how to search for an example to start. Any direction or other options would be appreciated.

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  • Stop CDATA tags from being output-escaped when writing to XML in C#

    - by Smallgods
    We're creating a system outputting some data to an XML schema. Some of the fields in this schema need their formatting preserved, as it will be parsed by the end system into potentially a Word doc layout. To do this we're using <![CDATA[Some formatted text]]> tags inside of the App.Config file, then putting that into an appropriate property field in a xsd.exe generated class from our schema. Ideally the formatting wouldn't be out problem, but unfortunately thats just how the system is going. The App.Config section looks as follows: <header> <![CDATA[Some sample formatted data]]> </header> The data assignment looks as follows: HeaderSection header = ConfigurationManager.GetSection("header") as HeaderSection; report.header = "<[CDATA[" + header.Header + "]]>"; Finally, the Xml output is handled as follows: xs = new XmlSerializer(typeof(report)); fs = new FileStream (reportLocation, FileMode.Create); xs.Serialize(fs, report); fs.Flush(); fs.Close(); This should in theory produce in the final Xml a section that has information with CDATA tags around it. However, the angled brackets are being converted into &lt; and &gt; I've looked at ways of disabling Outout Escaping, but so far can only find references to XSLT sheets. I've also tried @"<[CDATA[" with the strings, but again no luck. Any help would be appreciated!

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  • Tree-like queues

    - by Rehno Lindeque
    I'm implementing a interpreter-like project for which I need a strange little scheduling queue. Since I'd like to try and avoid wheel-reinvention I was hoping someone could give me references to a similar structure or existing work. I know I can simply instantiate multiple queues as I go along, I'm just looking for some perspective by other people who might have better ideas than me ;) I envision that it might work something like this: The structure is a tree with a single root. You get a kind of "insert_iterator" to the root and then push elements onto it (e.g. a and b in the example below). However, at any point you can also split the iterator into multiple iterators, effectively creating branches. The branches cannot merge into a single queue again, but you can start popping elements from the front of the queue (again, using a kind of "visitor_iterator") until empty branches can be discarded (at your discretion). x -> y -> z a -> b -> { g -> h -> i -> j } f -> b Any ideas? Seems like a relatively simple structure to implement myself using a pool of circular buffers but I'm following the "think first, code later" strategy :) Thanks

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  • Data Warehouse: Modelling a future schedule

    - by Pat
    I'm creating a DW that will contain data on financial securities such as bonds and loans. These securities are associated with payment schedules. For example, a bond could pay quarterly, while a mortage would usually pay monthly (sometimes biweekly). The payment schedule is created when the security is traded and, in the majority of cases, will remain unchanged. However, the design would need to accomodate those cases where it does change. I'm currently attempting to model this data and I'm having difficulty coming up with a workable design. One of the most commonly queried fields is "next payment date". Users often want to know when a security will pay next. Therefore, I want to make it as easy as possible for them to get the next payment date and amount for each security. Also, users often run historical queries in which case they'd want the next payment date and amount as of a specific point in time. For example, they may want to look back at 1/31/09 and query the next payment dates (which would usually be in February 2009 for mortgages). It's also common that they want to query a security's entire payment schedule, which might consist of 360 records (30 year mortgage x 12 payments/year). Since the next payment date and amount would be changing each month or even biweekly, these fields wouldn't seem to fit into a slow-changing dimension very well. It would probably make more sense to use a fact table, but I'm unsure of how to model it. Any ideas would be greatly appreciated.

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  • Django - partially validating form

    - by aeter
    I'm new to Django, trying to process some forms. I have this form for entering information (creating a new ad) in one template: class Ad(models.Model): ... category = models.CharField("Category",max_length=30, choices=CATEGORIES) sub_category = models.CharField("Subcategory",max_length=4, choices=SUBCATEGORIES) location = models.CharField("Location",max_length=30, blank=True) title = models.CharField("Title",max_length=50) ... I validate it with "is_valid()" just fine. Basically for the second validation (another template) I want to validate only against "category" and "sub_category": In another template, I want to use 2 fields from the same form ("category" and "sub_category") for filtering information - and now the "is_valid()" method would not work correctly, cause it validates the entire form, and I need to validate only 2 fields. I have tried with the following: ... if request.method == 'POST': # If a filter for data has been submitted: form = AdForm(request.POST) try: form = form.clean() category = form.category sub_category = form.sub_category latest_ads_list = Ad.objects.filter(category=category) except ValidationError: latest_ads_list = Ad.objects.all().order_by('pub_date') else: latest_ads_list = Ad.objects.all().order_by('pub_date') form = AdForm() ... but it doesn't work. How can I validate only the 2 fields category and sub_category?

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  • Ruby on Rails login using legacy user database

    - by ricsmania
    Hello, I have a Rails application that connects to a legacy database (Oracle) and displays some information from a particular user. Right now the user is passed as a URL parameter, but this has obvious security issues because users should only be able to see their own data. To solve that, I want to implement a user login, and I did some research and came across 2 components for that, restful_authentication and authlogic. The problem is that I need to use an existing user/password database instead of creating a new one, which is the common way to use those components. The password is encrypted by a custom Oracle package, but let's assume it is stored as plain text to make things simpler. I only need very basic functionality, which is login a user and keep them logged in forever until logout. No changes to the database will be made by this application, so there's no need for sign up, e-mail activation, reset password, etc. Can someone point me in the right direction on how to do that? Is any of those 2 components a good solution? If not, what would be recommended? Thanks!

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  • Domain validates but won't save

    - by marko
    I have the following setup. Class, say, Car that has a CarPart (belongsTo=[car:Car]). When I'm creating a Car I also want to create som default CarParts, so I do def car = new Car(bla bla bla) def part = new CarPart(car:car) Now, when I do car.validate() or part.validate() it seems fine. But when I do if(car.save && part.save() I get this exception: 2012-03-24 14:02:21,943 [http-8080-4] ERROR util.JDBCExceptionReporter - Batch entry 0 insert into car_part (version, car_id, id) values ('0', '297', '298') was aborted. Call getNextException to see the cause. 2012-03-24 14:02:21,943 [http-8080-4] ERROR util.JDBCExceptionReporter - ERROR: value too long for type character varying(6) 2012-03-24 14:02:21,943 [http-8080-4] ERROR events.PatchedDefaultFlushEventListener - Could not synchronize database state with session org.hibernate.exception.DataException: Could not execute JDBC batch update Stacktrace follows: java.sql.BatchUpdateException: Batch entry 0 insert into car_part (version, deal_id, id) values ('0', '297', '298') was aborted. Call getNextException to see the cause. at org.postgresql.jdbc2.AbstractJdbc2Statement$BatchResultHandler.handleError(AbstractJdbc2Statement.java:2621) at org.postgresql.core.v3.QueryExecutorImpl.processResults(QueryExecutorImpl.java:1837) at org.postgresql.core.v3.QueryExecutorImpl.execute(QueryExecutorImpl.java:407) at org.postgresql.jdbc2.AbstractJdbc2Statement.executeBatch(AbstractJdbc2Statement.java:2754) at $Proxy20.flush(Unknown Source) at ristretto.DealController$_closure5.doCall(DealController.groovy:109) at ristretto.DealController$_closure5.doCall(DealController.groovy) at java.lang.Thread.run(Thread.java:722) Any ideas?

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  • Binding a value to one of two possibilities in Guice

    - by Kelvin Chung
    Suppose I have a value for which I have a default, which can be overridden if System.getProperty("foo") is set. I have one module for which I have bindConstant().annotatedWith(Names.named("Default foo")).to(defaultValue); I'm wondering what the best way of implementing a module for which I want to bind something annotated with "foo" to System.getProperty("foo"), or, if it does not exist, the "Default foo" binding. I've thought of a simple module like so: public class SimpleIfBlockModule extends AbstractModule { @Override public void configure() { requireBinding(Key.get(String.class, Names.named("Default foo"))); if (System.getProperties().containsKey("foo")) { bindConstant().annotatedWith(Names.named("foo")).to(System.getProperty("foo")); } else { bind(String.class).annotatedWith(Names.named("foo")).to(Key.get(String.class, Names.named("Default foo"))); } } } I've also considered creating a "system property module" like so: public class SystemPropertyModule extends PrivateModule { @Override public void configure() { Names.bindProperties(binder(), System.getProperties()); if (System.getProperties().contains("foo")) { expose(String.class).annotatedWith(Names.named("foo")); } } } And using SystemPropertyModule to create an injector that a third module, which does the binding of "foo". Both of these seem to have their downsides, so I'm wondering if there is anything I should be doing differently. I was hoping for something that's both injector-free and reasonably generalizable to multiple "foo" attributes. Any ideas?

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  • WPF C# Client/Server announcement system

    - by manemawanna
    I'm currently in the process of creating an announcement system at my place of work. The role of this system will be to replace all users email due to people misusing it and generally abusing the facility. The system will consist of: Web Portal: Will allow staff to enter any important announcements (this will be restricted via AD). SQL Server 2k5 DB: Will hold the announcements along with records of staff members and if they've read the announcements etc. Front End: Created in WPF & C# which is nearly complete, it will display the announcements to the users. Web Page: Client will contact every so often, which will return an xml file for the client to read. However my boss has now shifted the goal posts and would like the announcements to appear to the user once they are written to the database, rather than waiting on the client to contact the webpage. So now I'm a bit unsure as to how to go about this. I have one idea where I would create a small server application to monitor for new announcements then contact the clients to inform them to approach the website for the information they need. But I'm just looking to see if theres a better or more efficient way to do this or if someone else has a more appropriate idea or suggestion.

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  • Custom UIButton Memory Management in dealloc

    - by ddawber
    I am hoping to clarify the processes going on here. I have created a subclass of UIButton whose init method looks like this: - (id)initWithTitle:(NSString *)title frame:(CGRect)btnFrame { self = [UIButton buttonWithType:UIButtonTypeCustom]; [self setTitle:title forState:UIControlStateNormal]; self.frame = btnFrame; return self; } In my view controller I am creating one of these buttons and adding it as a subview: myButton = [[CustomButton alloc] initWithTitle:@"Title" frame:someFrame]; [self.view addSubview:myButton]; In the view controller's dealloc method I log the retain count of my button: - (void)dealloc { NSLog(@"RC: %d", [myButton retainCount]); //RC = 2 [super dealloc]; NSLog(@"RC: %d", [myButton retainCount]); //RC = 1 } The way I understand it, myButton is not actually retained, even though I invoked it using alloc, because in my subclass I created an autorelease button (using buttonWithType:). In dealloc, does this mean that, when dealloc is called the superview releases the button and its retain count goes down to 1? The button has not yet been autoreleased? Or do I need to get that retain count down to zero after calling [super dealloc]? Cheers.

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  • Need help with threads in a client/server

    - by nunos
    For college, I am developing a local relay chat. I have to program a chat server and client that will only work on sending messages on different terminal windows on the same computer with threads and fifos. The fifos part I am having no trouble, the threads part is the one that is giving me some headaches. The server has one thread for receiving commands from a fifo (used by all clients) and another thread for each client that is connected. For each client that is connected I need to know a certain information. Firstly, I was using global variables, which worked as longs as there was only one client connected, which is much of a chat, to chat alone. So, ideally I would have some data like: -nickname -name -email -etc... per client that is connected. However, I don't know how to do that. I could create a client_data[MAX_NUMBER_OF_THREADS] where client_data was a struct with everything I needed to have access to, but this would require to, in every communication between server and client to ask for the id of the client in the array client_data and that does not seem very pratical I could also instantiate a client_data immediately after creating the thread but it would only be available in that block, and that is not very pratical either. As you can see I am in need of a little guidance here. Any comment, piece of code or link to any relevant information is greatly appreciated. Thanks.

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  • Reduce durability in MySQL for performance

    - by Paul Prescod
    My site occasionally has fairly predictable bursts of traffic that increase the throughput by 100 times more than normal. For example, we are going to be featured on a television show, and I expect in the hour after the show, I'll get more than 100 times more traffic than normal. My understanding is that MySQL (InnoDB) generally keeps my data in a bunch of different places: RAM Buffers commitlog binary log actual tables All of the above places on my DB slave This is too much "durability" given that I'm on an EC2 node and most of the stuff goes across the same network pipe (file systems are network attached). Plus the drives are just slow. The data is not high value and I'd rather take a small chance of a few minutes of data loss rather than have a high probability of an outage when the crowd arrives. During these traffic bursts I would like to do all of that I/O only if I can afford it. I'd like to just keep as much in RAM as possible (I have a fair chunk of RAM compared to the data size that would be touched over an hour). If buffers get scarce, or the I/O channel is not too overloaded, then sure, I'd like things to go to the commitlog or binary log to be sent to the slave. If, and only if, the I/O channel is not overloaded, I'd like to write back to the actual tables. In other words, I'd like MySQL/InnoDB to use a "write back" cache algorithm rather than a "write through" cache algorithm. Can I convince it to do that? If this is not possible, I am interested in general MySQL write-performance optimization tips. Most of the docs are about optimizing read performance, but when I get a crowd of users, I am creating accounts for all of them, so that's a write-heavy workload.

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  • Implementing a scrabble trainer (cheater)

    - by bstullkid
    Hello, I've recently been playing alot of online scrabble so I decided to make a program that quickly searches through a dictionary of 200,000+ words with an input of up to any 26 letters. My first attempt was fail as it took a while when you input 8 or more letters (just a basic look through dictionary and cancel out a letter if its found kind of thing), so I made a tree like structure containing only an array of 26 of the same structure and a flag to indicate the end of a word, doing that It can output all possible words in under a second even with an input of 26 characters. But it seems that when I input 12 or more letters with some of the same characters repeated i get duplicates; can anyone see why I would be getting duplicates with this code? (ill post my program at the bottom) Also, the next step once the duplicates are weeded out is to actually be able to input the letters on the game board and then have it calculate the best word you can make on a given board. I am having trouble trying to figure out a good algorithm that can analyze a scrabble board and an input of letters and output a result; the possible words that could be made I have no problem with but actually checking a board efficiently (ie can this word fit here, or here etc... without creating a non dictionary word in the process on some other string of letters) Anyone have a idea for an approach at that? (given a scrabble board, and an input of 7 letters, find all possible valid words or word sets that you can make) lol crap i forgot to email myself the code from my other computer thats in another state... ill post it on monday when I get back there! btw the dictionary im using is sowpods (http://www.calvin.edu/~rpruim/scrabble/ospd3.txt)

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