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  • SelectList in Asp-mvc and data from the database

    - by George
    Hello guys. I'm having some troubles with SelectList in ASP.MVC. Here is the issue: I have a Create View and begind a ViewModel model. The page load just fine (GET verb). But when posting, something happens, and my model is considered invalid, and it cannot insert. Here's what i've tried so far. public class DefinitionFormViewModel { private Repository<Category> categoryRepository = new Repository<Category>(); public Definition ViewDefinition { get; private set; } public SelectList Categories { get; private set; } public DefinitionFormViewModel(Definition def) { ViewDefinition = def; // here i wanted to place it directly, like shown in NerdDinner Tutorial // new SelectList(categoryRepository.All(),ViewDefinition.Category); Categories = new SelectList(categoryRepository.All(), "CategoryId", "CategoryName", ViewDefinition.CategoryId); } } // pageview which inherits DefinitionFormViewModel <div class=editor-field"> <%= Html.DropDownList("Category",Model.Categories) %> <%= Html.ValidationMessageFor(model => Model.ViewDefinition.Category) %> </div> // controller methods [Authorize] public ActionResult Create() { Definition definition = new Definition(); return View(new DefinitionFormViewModel(definition)); } [AcceptVerbs(HttpVerbs.Post), Authorize] public ActionResult Create(int id,Definition definition) { Term term = termRepository.SingleOrDefault(t => t.TermId == id); if (term == null) { return View("NotFound", new NotFoundModel("Termo não encontrado", "Termo não encontrado", "Nos desculpe, mas não conseguimos encontrar o termo solicitado.", "Indíce de Termos", "Index", "Term")); } else { if (ModelState.IsValid) { try { definition.TermId = term.TermId; definition.ResponsibleUser = User.Identity.Name; UpdateModel(definition); term.Definitions.Add(definition); termRepository.SaveAll(); return RedirectToAction("Details", "Term", new { id = term.TermId }); } catch (System.Data.SqlClient.SqlException sqlEx) { ModelState.AddModelError("DatabaseError", "Houve um erro na inserção desta nova definição"); } catch { foreach (RuleViolation rv in definition.GetRuleViolations()) { ModelState.AddModelError(rv.PropertyName, rv.ErrorMessage); } } } } return View(new DefinitionFormViewModel(definition)); } I'm sorry about the long post, but I cant figure this out. I got no graphic errors or exceptions. My execution terminates in if (ModelState.IsValid). Thanks for your time George

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  • MKMap showing detail of annotations

    - by yeohchan
    I have encountered a problem of populating the description for each annotation. Each annotation works, but there is somehow an area when trying to click on it. Here is the code. the one in bold is the one that has the problem. -(void)viewDidLoad{ FlickrFetcher *fetcher=[FlickrFetcher sharedInstance]; NSArray *rec=[fetcher recentGeoTaggedPhotos]; for(NSDictionary *dic in rec){ NSLog(@"%@",dic); NSDictionary *string = [fetcher locationForPhotoID:[dic objectForKey:@"id"]]; double latitude = [[string objectForKey:@"latitude"] doubleValue]; double longitude = [[string objectForKey:@"longitude"]doubleValue]; if(latitude !=0 && latitude != 0 ){ CLLocationCoordinate2D coordinate1 = { latitude,longitude }; **NSDictionary *adress=[NSDictionary dictionaryWithObjectsAndKeys:[dic objectForKey:@"owner"],[dic objectForKey:@"title"],nil];** MKPlacemark *anArea=[[MKPlacemark alloc]initWithCoordinate:coordinate1 addressDictionary:adress]; [mapView addAnnotation:anArea]; } } } Here is what the Flickr class does: #import <Foundation/Foundation.h> #define TEST_HIGH_NETWORK_LATENCY 0 typedef enum { FlickrFetcherPhotoFormatSquare, FlickrFetcherPhotoFormatLarge } FlickrFetcherPhotoFormat; @interface FlickrFetcher : NSObject { NSManagedObjectModel *managedObjectModel; NSManagedObjectContext *managedObjectContext; NSPersistentStoreCoordinator *persistentStoreCoordinator; } // Returns the 'singleton' instance of this class + (id)sharedInstance; // // Local Database Access // // Checks to see if any database exists on disk - (BOOL)databaseExists; // Returns the NSManagedObjectContext for inserting and fetching objects into the store - (NSManagedObjectContext *)managedObjectContext; // Returns an array of objects already in the database for the given Entity Name and Predicate - (NSArray *)fetchManagedObjectsForEntity:(NSString*)entityName withPredicate:(NSPredicate*)predicate; // Returns an NSFetchedResultsController for a given Entity Name and Predicate - (NSFetchedResultsController *)fetchedResultsControllerForEntity:(NSString*)entityName withPredicate:(NSPredicate*)predicate; // // Flickr API access // NOTE: these are blocking methods that wrap the Flickr API and wait on the results of a network request // // Returns an array of Flickr photo information for photos with the given tag - (NSArray *)photosForUser:(NSString *)username; // Returns an array of the most recent geo-tagged photos - (NSArray *)recentGeoTaggedPhotos; // Returns a dictionary of user info for a given user ID. individual photos contain a user ID keyed as "owner" - (NSString *)usernameForUserID:(NSString *)userID; // Returns the photo for a given server, id and secret - (NSData *)dataForPhotoID:(NSString *)photoID fromFarm:(NSString *)farm onServer:(NSString *)server withSecret:(NSString *)secret inFormat:(FlickrFetcherPhotoFormat)format; // Returns a dictionary containing the latitue and longitude where the photo was taken (among other information) - (NSDictionary *)locationForPhotoID:(NSString *)photoID; @end

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  • How to return the date value from DatePickerDialog in Android?

    - by user1855222
    I am new to android . I ve created a Date picker in android using following guide .http://developer.android.com/guide/topics/ui/controls/pickers.html public class DatePickerFragment extends DialogFragment implements DatePickerDialog.OnDateSetListener { StringBuilder sb = new StringBuilder(); public static String date; @Override public Dialog onCreateDialog(Bundle savedInstanceState) { // Use the current date as the default date in the picker final Calendar c = Calendar.getInstance(); int year = c.get(Calendar.YEAR); int month = c.get(Calendar.MONTH); int day = c.get(Calendar.DAY_OF_MONTH); // Create a new instance of DatePickerDialog and return it return new DatePickerDialog(getActivity(), this, year, month, day); } public void onDateSet(DatePicker view, int year, int month, int day) { // Do something with the date chosen by the user sb.append(year); sb.append('-'); sb.append(month+1); sb.append('-'); sb.append(day); date = sb.toString(); System.out.println("The date is "+date); } I need to return this date value (date = sb.toString()) to my MainActivity . Since the onDateSet method is void what should I do ? Additional Information - DatePickerDialog Triggers at the MainActivity class ,But not with single button click . There are several processes happens in side a single button , Date picker will triggers only when certain condition is met . I do not want to display the date value either . Just want it returned for further processing. Appreciate any kind of guidance Changed onDataset method and justshow() public void onDateSet(DatePicker view, int year, int month, int day) { // Do something with the date chosen by the user sb.append(year); sb.append('-'); sb.append(month+1); sb.append('-'); sb.append(day); date = sb.toString(); MainActivity.newdate=sb.toString(); System.out.println("The date is "+MainActivity.newdate); } public void justShow(){ System.out.println("The date is "+MainActivity.newdate); } This is the relevant Part From Main(After making changes suggested in first reply ) DateToken mydate=new DateToken(); String test=dayvals.get(0); DialogFragment df=new DatePickerFragment(); if(test.equalsIgnoreCase("day")){ df.show(getSupportFragmentManager(), "DatePik"); } System.out.println("Date is on Main"+newdate); DatePickerFragment dpf=new DatePickerFragment(); dpf.justShow(); newdate is the static String , but still outputs null. In both MainActivity and justShow methods . But in onDataSet method date outputs correctly

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  • Java: omitting a data member from the equals method.

    - by cchampion
    public class GamePiece { public GamePiece(char cLetter, int nPointValue) { m_cLetter=cLetter; m_nPointValue=nPointValue; m_nTurnPlaced=0; //has not been placed on game board yet. } public char GetLetter() {return m_cLetter;} public int GetPointValue() {return m_nPointValue;} public int GetTurnPlaced() {return m_nTurnPlaced;} public void SetTurnPlaced(int nTurnPlaced) { m_nTurnPlaced=nTurnPlaced; } @Override public boolean equals(Object obj) { /*NOTE to keep this shorter I omitted some of the null checking and instanceof stuff. */ GamePiece other = (GamePiece) obj; //not case sensitive, and I don`t think we want it to be here. if(m_cLetter != other.m_cLetter) { return false; } if(m_nPointValue != other.m_nPointValue) { return false; } /* NOTICE! m_nPointValue purposely omitted. It does not affect hashcode or equals */ return true; } @Override public int hashCode() { /* NOTICE! m_nPointValue purposely omitted. It should not affect hashcode or equals */ final int prime = 41; return prime * (prime + m_nPointValue + m_cLetter); } private char m_cLetter; private int m_nPointValue; private int m_nTurnPlaced;//turn which the game piece was placed on the game board. Does not affect equals or has code! } Consider the given piece of code. This object has been immutable until the introduction of the m_nTurnPlaced member (which can be modified by the SetTurnPlaced method, so now GamePiece becomes mutable). GamePiece is used in an ArrayList, I call contains and remove methods which both rely on the equals method to be implemented. My question is this, is it ok or common practice in Java for some members to not affect equals and hashcode? How will this affect its use in my ArrayList? What type of java Collections would it NOT be safe to use this object now that it is mutable? I've been told that you're not supposed to override equals on mutable objects because it causes some collections to behave "strangely" (I read that somewhere in the java documentation).

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  • Can I call make runtime decided method calls in Java?

    - by Catalin Marin
    I know there is an invoke function that does the stuff, I am overall interested in the "correctness" of using such a behavior. My issue is this: I have a Service Object witch contains methods which I consider services. What I want to do is alter the behavior of those services without later intrusion. For example: class MyService { public ServiceResponse ServeMeDonuts() { do stuff... return new ServiceResponse(); } after 2 months I find out that I need to offer the same service to a new client app and I also need to do certain extra stuff like setting a flag, or make or updating certain data, or encode the response differently. What I can do is pop it up and throw down some IFs. In my opinion this is not good as it means interaction with tested code and may result in un wanted behaviour for the previous service clients. So I come and add something to my registry telling the system that the "NewClient" has a different behavior. So I'll do something like this: public interface Behavior { public void preExecute(); public void postExecute(); } public class BehaviorOfMyService implements Behavior{ String method; String clientType; public void BehaviorOfMyService(String method,String clientType) { this.method = method; this.clientType = clientType; } public void preExecute() { Method preCall = this.getClass().getMethod("pre" + this.method + this.clientType); if(preCall != null) { return preCall.invoke(); } return false; } ...same for postExecute(); public void preServeMeDonutsNewClient() { do the stuff... } } when the system will do something like this if(registrySaysThereIs different behavior set for this ServiceObject) { Class toBeCalled = Class.forName("BehaviorOf" + usedServiceObjectName); Object instance = toBeCalled.getConstructor().newInstance(method,client); instance.preExecute(); ....call the service... instance.postExecute(); .... } I am not particularly interested in correctness of code as in correctness of thinking and approach. Actually I have to do this in PHP, witch I see as a kind of Pop music of programming which I have to "sing" for commercial reasons, even though I play POP I really want to sing by the book, so putting aside my more or less inspired analogy I really want to know your opinion on this matter for it's practical necessity and technical approach. Thanks

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  • Inserting contact with android and querying the result uri returns no entries

    - by th0m4d
    Im developing an application which is dealing with the android contacts API. I implemented methods to insert, update and query contacts. So far everything worked (writing and reading contacts). At one point in my project Im experiencing a strange behaviour. I insert a contact using batch mode. I receive the URI to the RawContact. I do this in a background thread. // use batchmode for contact insertion ArrayList ops = new ArrayList(); int rawContactInsertIndex = ops.size(); // create rawContact ops.add(ContentProviderOperation.newInsert(RawContacts.CONTENT_URI) .withValue(RawContacts.ACCOUNT_TYPE, ConstantsContract.ACCOUNT_TYPE) .withValue(RawContacts.ACCOUNT_NAME, accountName).build()); ops.add(createInsertOperation().withValueBackReference(Data.RAW_CONTACT_ID, rawContactInsertIndex) .withValue(Data.MIMETYPE, StructuredName.CONTENT_ITEM_TYPE) .withValue(StructuredName.DISPLAY_NAME, displayName).withValue(StructuredName.GIVEN_NAME, firstName) .withValue(StructuredName.FAMILY_NAME, lastName).build()); //other data values... ContentProviderResult[] results = context.getContentResolver().applyBatch(ContactsContract.AUTHORITY, ops); if (results.length 0) { result = results[0]; } Then i request and store the lookup uri RawContacts.getContactLookupUri(this.getContentResolver(), myContantRawContactUri); I am able to query the contact using the rawContactUri directly after inserting it (in the same thread). The lookup uri returns null. Uri rawContactUri = appUser.getRawContactUri(ctx); if (rawContactUri == null) { return null; } String lastPathSegment = rawContactUri.getLastPathSegment(); long rawContactId = Long.decode(lastPathSegment); if (rawContactUri != null) { contact = readContactWithID(rawContactId, ContactsContract.Data.RAW_CONTACT_ID); In a different place in the project I want to query the contact i inserted by the stored lookup uri or raw contact uri. Both return no rows from the content provider. I tried it in the main thread and in another background thread. ctx.getContentResolver().query(ContactsContract.Data.CONTENT_URI, null, ContactsContract.Data.RAW_CONTACT_ID + " = ? AND " + ContactsContract.Data.MIMETYPE + " = ?", new String[] { contactID + "", ContactsContract.CommonDataKinds.StructuredName.CONTENT_ITEM_TYPE }, null); My first thought was that it could be related to the context.getContentResolver(). But the android documentation states, that the ContentResolver objects scope is the application's package, so you have on ContentResolver for the whole app. Am I right? What am I doing wrong? Why does the same rawContactUri return the contact at one place and does not on another place? And why do I get a lookup uri from a raw contact, which is not working at all?

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  • Need Help on OAuthException Code 2500

    - by Deepak
    I am trying to develop an Facebook application (apps.facebook.com/some_app) using PHP where I need to present some information based on user's music interests. I found that its under "user_likes games". My problems are as follows: To gain access, I have implemented the oauth dialog method as suggested in API in my index page. $auth_url = "http://www.facebook.com/dialog/oauth?client_id=" . $app_id . "&redirect_uri=" . urlencode($canvas_page) ."&scope=user_likes"; After successful authorization I come back to index page with "code" as parameters. http://MY_CANVAS_PAGE/?code=some base64 encoded letters Firstly I don't know if I need access_token just to read user's music interests but I have tried all the methods suggested. I couldn't move forward from this point I have a code like this (in my index page), which redirects for authorization if code parameters is not set. if(empty($code) && !isset($_REQUEST['error'])) { $_SESSION['state'] = md5(uniqid(rand(), TRUE)); //CSRF protection echo("<script> top.location.href='" . $auth_url . "'</script>"); } Currently I am just trying to get user's public information here but with no success. I have tried the signed_request method as suggested but no success $signed_request = $_REQUEST["signed_request"]; list($encoded_sig, $payload) = explode('.', $signed_request, 2); $data = json_decode(base64_decode(strtr($payload, '-_', '+/')), true); echo ("Welcome User: " . $data["user_id"]); Also tried the code found in http://developers.facebook.com/blog/post/500/ but I am getting error when trying to get the debug info using print_r($decoded_response); stdClass Object ( [error] => stdClass Object ( [message] => An active access token must be used to query information about the current user. [type] => OAuthException [code] => 2500 ) ) To get user's public info, I have tried also the suggested example in PHP SDK $facebook = new Facebook(array( 'appId' => MY_APP_ID, //registered facebook APP ID 'secret' => MY_SECRET, //secret key for APP )); $fb_user = $facebook->getUser(); if($fb_user){ try { $user_profile = $facebook->api('/me'); echo $user_profile['email']; } catch(FacebookApiException $e) { $fb_user = null; } } But no success. Can somebody explain me why I am getting this error and how to access the user's music interest properly. Probably I misunderstood the API. Thanks Deepak

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  • Is it possible to reliably auto-decode user files to Unicode? [C#]

    - by NVRAM
    I have a web application that allows users to upload their content for processing. The processing engine expects UTF8 (and I'm composing XML from multiple users' files), so I need to ensure that I can properly decode the uploaded files. Since I'd be surprised if any of my users knew their files even were encoded, I have very little hope they'd be able to correctly specify the encoding (decoder) to use. And so, my application is left with task of detecting before decoding. This seems like such a universal problem, I'm surprised not to find either a framework capability or general recipe for the solution. Can it be I'm not searching with meaningful search terms? I've implemented BOM-aware detection (http://en.wikipedia.org/wiki/Byte_order_mark) but I'm not sure how often files will be uploaded w/o a BOM to indicate encoding, and this isn't useful for most non-UTF files. My questions boil down to: Is BOM-aware detection sufficient for the vast majority of files? In the case where BOM-detection fails, is it possible to try different decoders and determine if they are "valid"? (My attempts indicate the answer is "no.") Under what circumstances will a "valid" file fail with the C# encoder/decoder framework? Is there a repository anywhere that has a multitude of files with various encodings to use for testing? While I'm specifically asking about C#/.NET, I'd like to know the answer for Java, Python and other languages for the next time I have to do this. So far I've found: A "valid" UTF-16 file with Ctrl-S characters has caused encoding to UTF-8 to throw an exception (Illegal character?) (That was an XML encoding exception.) Decoding a valid UTF-16 file with UTF-8 succeeds but gives text with null characters. Huh? Currently, I only expect UTF-8, UTF-16 and probably ISO-8859-1 files, but I want the solution to be extensible if possible. My existing set of input files isn't nearly broad enough to uncover all the problems that will occur with live files. Although the files I'm trying to decode are "text" I think they are often created w/methods that leave garbage characters in the files. Hence "valid" files may not be "pure". Oh joy. Thanks.

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  • How do I replace values within a data frame with a string in R?

    - by Arturito
    short version: How do I replace values within a data frame with a string found within another data frame? longer version: I'm a biologist working with many species of bees. I have a data set with many thousands of bees. Each row has a unique bee ID # along with all the relevant info about that specimen (data of capture, GPS location, etc). The species information for each bee has not been entered because it takes a long time to ID them. When IDing, I end up with boxes of hundred of bees, all of the same species. I enter these into a separate data frame. I am trying to write code that will update the original data file with species information (family, genus, species, sex, etc) as I ID the bees. Currently, in the original data file, the species info is blank and is interpreted as NA within R. I want to have R find all unique bee ID #'s and fill in the species info, but I am having trouble figuring out how to replace the NA values with a string (e.g. "Andrenidae") Here is a simple example of what I am trying to do: rawData<-data.frame(beeID=c(1:20),family=rep(NA,20)) speciesInfo<-data.frame(beeID=seq(1,20,3),family=rep("Andrenidae",7)) rawData[rawData$beeID == 4,"family"] <- speciesInfo[speciesInfo$beeID == 4,"family"] So, I am replacing things as I want, but with a number rather than the family name (a string). What I would eventually like to do is write a little loop to add in all the species info, e.g.: for (i in speciesInfo$beeID){ rawData[rawData$beeID == i,"family"] <- speciesInfo[speciesInfo$beeID == i,"family"] } Thanks in advance for any advice! Cheers, Zak EDIT: I just noticed that the first two methods below add a new column each time, which would cause problems if I needed to add species info multiple times (which I typically do). For example: rawData<-data.frame(beeID=c(1:20),family=rep(NA,20)) Andrenidae<-data.frame(beeID=seq(1,20,3),family=rep("Andrenidae",7)) Halictidae<-data.frame(beeID=seq(1,20,3)+1,family=rep("Halictidae",7)) # using join library(plyr) rawData <- join(rawData, Andrenidae, by = "beeID", type = "left") rawData <- join(rawData, Halictidae, by = "beeID", type = "left") # using merge rawData <- merge(x=rawData,y=Andrenidae,by='beeID',all.x=T,all.y=F) rawData <- merge(x=rawData,y=Halictidae,by='beeID',all.x=T,all.y=F) Is there a way to either collapse the columns so that I have one, unified data frame? Or a way to update the rawData rather than adding a new column each time? Thanks in advance!

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  • Establishing a tcp connection from within a DLL

    - by Nicholas Hollander
    I'm trying to write a piece of code that will allow me to establish a TCP connection from within a DLL file. Here's my situation: I have a ruby application that needs to be able to send and receive data over a socket, but I can not access the native ruby socket methods because of the environment in which it will be running. I can however access a DLL file and run the functions within that, so I figured I would create a wrapper for winsock. Unfortunately, attempting to take a piece of code that should connect to a TCP socket in a normal C++ application throws a slew of LNK2019 errors that I can not for the life of me resolve. This is the method I'm using to connect: //Socket variable SOCKET s; //Establishes a connection to the server int server_connect(char* addr, int port) { //Start up Winsock WSADATA wsadata; int error = WSAStartup(0x0202, &wsadata); //Check if something happened if (error) return -1; //Verify Winock version if (wsadata.wVersion != 0x0202) { //Clean up and close WSACleanup(); return -2; } //Get the information needed to finalize a socket SOCKADDR_IN target; target.sin_family = AF_INET; //Address family internet target.sin_port = _WINSOCKAPI_::htons(port); //Port # target.sin_addr.s_addr = inet_addr(addr); //Create the socket s = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP); if (s == INVALID_SOCKET) { return -3; } //Try connecting if (connect(s, (SOCKADDR *)&target, sizeof(target)) == SOCKET_ERROR) { //Failed to connect return -4; } else { //Success return 1; } } The exact errors that I'm receiving are: Error 1 error LNK2019: unresolved external symbol _closesocket@4 referenced in function _server_disconnect [Project Path] Error 2 error LNK2019: unresolved external symbol _connect@12 referenced in function _server_connect [Project Path] Error 3 error LNK2019: unresolved external symbol _htons@4 referenced in function _server_connect [Project Path] Error 4 error LNK2019: unresolved external symbol _inet_addr@4 referenced in function _server_connect [Project Path] Error 5 error LNK2019: unresolved external symbol _socket@12 referenced in function _server_connect [Project Path] Error 6 error LNK2019: unresolved external symbol _WSAStartup@8 referenced in function _server_connect [Project Path] Error 7 error LNK2019: unresolved external symbol _WSACleanup@0 referenced in function _server_connect [Project Path] Error 8 error LNK1120: 7 unresolved externals [Project Path] 1 1 Many thanks!

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  • Is there a better way to avoid an infinite loop using winforms?

    - by Hamish Grubijan
    I am using .Net 3.5 for now. Right now I am using a using trick to disable and enable events around certain sections of code. The user can change either days, hours, minutes or total minutes, and that should not cause an infinite cascade of events (e.g. minutes changing total, total changing minutes, etc.) While the code does what I want, there might be a better / more straight-forward way. Do you know of any? For brawny points: This control will be used by multiple teams - I do not want to make it embarrassing. I suspect that I do not need to reinvent the wheel when defining hours in a day, days in week, etc. Some other standard .Net library out there must have it. Any other remarks regarding code? This using (EventHacker.DisableEvents(this)) business - that must be a common pattern in .Net ... changing the setting temporarily. What is the name of it? I'd like to be able to refer to it in a comment and also read up more on current implementations. In the general case not only a handle to the thing being changed needs to be remembered, but also the previous state (in this case previous state does not matter - events are turned on and off unconditionally). Then there is also a possibility of multi-threaded hacking. One could also utilize generics to make the code arguably cleaner. Figuring all this out can lead to a multi-page blog post. I'd be happy to hear some of the answers. P.S. Does it seem like I suffer from obsessive compulsive disorder? Some people like to get things finished and move on; I like to keep them open ... there is always a better way. // Corresponding Designer class is omitted. using System; using System.Windows.Forms; namespace XYZ // Real name masked { interface IEventHackable { void EnableEvents(); void DisableEvents(); } public partial class PollingIntervalGroupBox : GroupBox, IEventHackable { private const int DAYS_IN_WEEK = 7; private const int MINUTES_IN_HOUR = 60; private const int HOURS_IN_DAY = 24; private const int MINUTES_IN_DAY = MINUTES_IN_HOUR * HOURS_IN_DAY; private const int MAX_TOTAL_DAYS = 100; private static readonly decimal MIN_TOTAL_NUM_MINUTES = 1; // Anything faster than once per minute can bog down our servers. private static readonly decimal MAX_TOTAL_NUM_MINUTES = (MAX_TOTAL_DAYS * MINUTES_IN_DAY) - 1; // 99 days should be plenty. // The value above was chosen so to not cause an overflow exception. // Watch out for it - numericUpDownControls each have a MaximumValue setting. public PollingIntervalGroupBox() { InitializeComponent(); InitializeComponentCustom(); } private void InitializeComponentCustom() { this.m_upDownDays.Maximum = MAX_TOTAL_DAYS - 1; this.m_upDownHours.Maximum = HOURS_IN_DAY - 1; this.m_upDownMinutes.Maximum = MINUTES_IN_HOUR - 1; this.m_upDownTotalMinutes.Maximum = MAX_TOTAL_NUM_MINUTES; this.m_upDownTotalMinutes.Minimum = MIN_TOTAL_NUM_MINUTES; } private void m_upDownTotalMinutes_ValueChanged(object sender, EventArgs e) { setTotalMinutes(this.m_upDownTotalMinutes.Value); } private void m_upDownDays_ValueChanged(object sender, EventArgs e) { updateTotalMinutes(); } private void m_upDownHours_ValueChanged(object sender, EventArgs e) { updateTotalMinutes(); } private void m_upDownMinutes_ValueChanged(object sender, EventArgs e) { updateTotalMinutes(); } private void updateTotalMinutes() { this.setTotalMinutes( MINUTES_IN_DAY * m_upDownDays.Value + MINUTES_IN_HOUR * m_upDownHours.Value + m_upDownMinutes.Value); } public decimal TotalMinutes { get { return m_upDownTotalMinutes.Value; } set { m_upDownTotalMinutes.Value = value; } } public decimal TotalHours { set { setTotalMinutes(value * MINUTES_IN_HOUR); } } public decimal TotalDays { set { setTotalMinutes(value * MINUTES_IN_DAY); } } public decimal TotalWeeks { set { setTotalMinutes(value * DAYS_IN_WEEK * MINUTES_IN_DAY); } } private void setTotalMinutes(decimal nTotalMinutes) { if (nTotalMinutes < MIN_TOTAL_NUM_MINUTES) { setTotalMinutes(MIN_TOTAL_NUM_MINUTES); return; // Must be carefull with recursion. } if (nTotalMinutes > MAX_TOTAL_NUM_MINUTES) { setTotalMinutes(MAX_TOTAL_NUM_MINUTES); return; // Must be carefull with recursion. } using (EventHacker.DisableEvents(this)) { // First set the total minutes this.m_upDownTotalMinutes.Value = nTotalMinutes; // Then set the rest this.m_upDownDays.Value = (int)(nTotalMinutes / MINUTES_IN_DAY); nTotalMinutes = nTotalMinutes % MINUTES_IN_DAY; // variable reuse. this.m_upDownHours.Value = (int)(nTotalMinutes / MINUTES_IN_HOUR); nTotalMinutes = nTotalMinutes % MINUTES_IN_HOUR; this.m_upDownMinutes.Value = nTotalMinutes; } } // Event magic public void EnableEvents() { this.m_upDownTotalMinutes.ValueChanged += this.m_upDownTotalMinutes_ValueChanged; this.m_upDownDays.ValueChanged += this.m_upDownDays_ValueChanged; this.m_upDownHours.ValueChanged += this.m_upDownHours_ValueChanged; this.m_upDownMinutes.ValueChanged += this.m_upDownMinutes_ValueChanged; } public void DisableEvents() { this.m_upDownTotalMinutes.ValueChanged -= this.m_upDownTotalMinutes_ValueChanged; this.m_upDownDays.ValueChanged -= this.m_upDownDays_ValueChanged; this.m_upDownHours.ValueChanged -= this.m_upDownHours_ValueChanged; this.m_upDownMinutes.ValueChanged -= this.m_upDownMinutes_ValueChanged; } // We give as little info as possible to the 'hacker'. private sealed class EventHacker : IDisposable { IEventHackable _hackableHandle; public static IDisposable DisableEvents(IEventHackable hackableHandle) { return new EventHacker(hackableHandle); } public EventHacker(IEventHackable hackableHandle) { this._hackableHandle = hackableHandle; this._hackableHandle.DisableEvents(); } public void Dispose() { this._hackableHandle.EnableEvents(); } } } }

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  • How to check for palindrome using Python logic

    - by DrOnline
    My background is only a 6 month college class in basic C/C++, and I'm trying to convert to Python. I may be talking nonsense, but it seems to me C, at least at my level, is very for-loop intensive. I solve most problems with these loops. And it seems to me the biggest mistake people do when going from C to Python is trying to implement C logic using Python, which makes things run slowly, and it's just not making the most of the language. I see on this website: http://hyperpolyglot.org/scripting (serach for "c-style for", that Python doesn't have C-style for loops. Might be outdated, but I interpret it to mean Python has its own methods for this. I've tried looking around, I can't find much up to date (Python 3) advice for this. How can I solve a palindrome challenge in Python, without using the for loop? I've done this in C in class, but I want to do it in Python, on a personal basis. The problem is from the Euler Project, great site btw. def isPalindrome(n): lst = [int(n) for n in str(n)] l=len(lst) if l==0 || l==1: return True elif len(lst)%2==0: for k in range (l) ##### else: while (k<=((l-1)/2)): if (list[]): ##### for i in range (999, 100, -1): for j in range (999,100, -1): if isPalindrome(i*j): print(i*j) break I'm missing a lot of code here. The five hashes are just reminders for myself. Concrete questions: 1) In C, I would make a for loop comparing index 0 to index max, and then index 0+1 with max-1, until something something. How to best do this in Python? 2) My for loop (in in range (999, 100, -1), is this a bad way to do it in Python? 3) Does anybody have any good advice, or good websites or resources for people in my position? I'm not a programmer, I don't aspire to be one, I just want to learn enough so that when I write my bachelor's degree thesis (electrical engineering), I don't have to simultaneously LEARN an applicable programming language while trying to obtain good results in the project. "How to go from basic C to great application of Python", that sort of thing. 4) Any specific bits of code to make a great solution to this problem would also be appreciated, I need to learn good algorithms.. I am envisioning 3 situations. If the value is zero or single digit, if it is of odd length, and if it is of even length. I was planning to write for loops... PS: The problem is: Find the highest value product of two 3 digit integers that is also a palindrome.

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  • How to define generic super type for static factory method?

    - by Esko
    If this has already been asked, please link and close this one. I'm currently prototyping a design for a simplified API of a certain another API that's a lot more complex (and potentially dangerous) to use. Considering the related somewhat complex object creation I decided to use static factory methods to simplify the API and I currently have the following which works as expected: public class Glue<T> { private List<Type<T>> types; private Glue() { types = new ArrayList<Type<T>>(); } private static class Type<T> { private T value; /* some other properties, omitted for simplicity */ public Type(T value) { this.value = value; } } public static <T> Glue<T> glueFactory(String name, T first, T second) { Glue<T> g = new Glue<T>(); Type<T> firstType = new Glue.Type<T>(first); Type<T> secondType = new Glue.Type<T>(second); g.types.add(firstType); g.types.add(secondType); /* omitted complex stuff */ return g; } } As said, this works as intended. When the API user (=another developer) types Glue<Horse> strongGlue = Glue.glueFactory("2HP", new Horse(), new Horse()); he gets exactly what he wanted. What I'm missing is that how do I enforce that Horse - or whatever is put into the factory method - always implements both Serializable and Comparable? Simply adding them to factory method's signature using <T extends Comparable<T> & Serializable> doesn't necessarily enforce this rule in all cases, only when this simplified API is used. That's why I'd like to add them to the class' definition and then modify the factory method accordingly. PS: No horses (and definitely no ponies!) were harmed in writing of this question.

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  • Why is my Interface Builder wiring so bonkers and what can I do to straighten it out?

    - by editor
    I've been working on an iPhone application in XCode and Interface Builder of the Tab Bar project type. After getting a table view of topics (business sectors) working fine I realized that I would need to add a Navigation Control to allow the user to drill into a subtopics (subsectors) table. As a green Objective-C developer, that was confusing, but I managed to get it working by reading various documentation trying out a few different IB options. My current setup is a Tab Bar Controller with Tab 1 as a Navigation Controller and Tab 2 a plain view with a Table View placed into it. The wiring works: I can log when table rows are selected and I'm ready to push a new View Controller onto the stack so that I can display the subtopics Table View. My problem: For some reason the first tab's Table View is a delegate and dataSource of the second ta. It doesn't make sense to me and I can't figure out why that's the only setup that works. Here is the wiring: Navigation Controller (Sectors) is a delegate of Tab Bar Navigation Bar is a delegate of Navigation Controller (Sectors) View Contoller (Sectors) has a view of Table View Table View (in Navigation Controller (Sectors)) is a delegate of First View Controller (Companies) Table View (in Navigation Controller (Sectors)) is a dataSource outlet of First View Controller (Companies) First View Controller (Companies) First View Contoller (Sectors) has a view of Table View Table View (in First View Controller (Companies)) is not hooked up to a dataSource outlet and is not a delegate When I click the tab buttons and look at the Inspector I see that the first tab is correctly hooked up to my MainWindow.xib and the second tab has selected a nib called SecondView.xib. It's in the File's Owner of MainWindow.xib where I inherit UITableViewDataSource and UITableViewDelegate (and also UITabBarControllerDelegate) in the .h, and in the .m where I implement the delegate methods. Why does this setup only work when the Table View in my first tab (View Controller (Sectors)) is a delegate and dataSource of the second tab? I'm confused: why wouldn't it need to be hooked up to the Navigation Controller-enabled tab in which the Table View is seen (Navigation Controller (Sectors))? The Table View seen on the second tab has neither dataSource and is not a delegate. I'm having trouble getting a pushViewController to fire (self.navigationController is not nil but the new View Controller still doesn't load) and I suspect that I need to work out this IB wiring issue before I can troubleshoot why the Nav Controller won't push a new View Controller onto the stack. if(nil == self.navigationController) { NSLog(@"self.navigationController is nil."); } else { NSLog(@"self.navigationController is not nil."); SectorList *subsectorViewController = [[SectorList alloc] initWithNibName:@"SectorList" bundle:nil]; subsectorViewController.title = @"Subsectors"; [[self navigationController] pushViewController:subsectorViewController animated:YES]; [subsectorViewController release]; }

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  • Question about design (inheritance, polymorphism)

    - by Dan
    Hi, I have a question about a problem I'm struggling with. Hope you can bear with me. Imagine I have an Object class representing the base class of a hierarchy of physical objects. Later I inherit from it to create an Object1D, Object2D and Object3D classes. Each of these derived classes will have some specific methods and attributes. For example, the 3d object might have functionality to download a 3d model to be used by a renderer. So I'd have something like this: class Object {}; class Object1D : public Object { Point mPos; }; class Object2D : public Object { ... }; class Object3D : public Object { Model mModel; }; Now I'd have a separate class called Renderer, which simply takes an Object as argument and well, renders it :-) In a similar way, I'd like to support different kinds of renderers. For instance, I could have a default one that every object could rely on, and then provide other specific renderers for some kind of objects: class Renderer {}; // Default one class Renderer3D : public Renderer {}; And here comes my problem. A renderer class needs to get an Object as an argument, for example in the constructor in order to retrieve whatever data it needs to render the object. So far so good. But a Renderer3D would need to get an Object3D argument, in order to get not only the basic attributes but also the specific attributes of a 3d object. Constructors would look like this: CRenderer(Object& object); CRenderer3D(Object3D& object); Now how do I specify this in a generic way? Or better yet, is there a better way to design this? I know I could rely on RTTI or similar but I'd like to avoid this if possible as I feel there is probably a better way to deal with this. Thanks in advance!

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  • D3 fisheye on width on bar chart

    - by Dexter Tan
    i have been trying to create a vertical bar chart with a d3 fisheye cartesian distortion with only the x-axis being distorted. I have succeeded in distorting the x position of the vertical bars on mouseover with the following code: var maxMag = d3.max(dataset, function(d) { return d.value[10]; }); var minDate = d3.min(dataset, function(d) { return new Date(d.value[1], d.value[2]-1, d.value[3]).getTime(); }); var maxDate = d3.max(dataset, function(d) { return new Date(d.value[1], d.value[2]-1, d.value[3]).getTime(); }); var yScale = d3.scale.linear().domain([0, maxMag]).range([0, h]); var xScale = d3.fisheye.scale(d3.scale.linear).domain([minDate, maxDate]).range([0, w]).focus(w/2); var bar = svg.append("g") .attr("class", "bars") .selectAll(".bar") .data(dataset) .enter().append("rect") .attr("class", "bar") .attr("y", function(d) { return h - yScale(d.value[10]); }) .attr("width", w/dataset.length) .attr("height", function(d) { return yScale(d.value[10]); }) .attr("fill", function(d) { return (d.value[10] <= 6? "yellow" : "orange" ); }) .call(position); // Positions the bars based on data. function position(bar) { bar.attr("x", function(d) { var date = null; if (d.date != null) { date = d.date; } else { date = new Date(d.value[1],0,1); if (d.value[2] != null) date.setMonth(d.value[2]-1); if (d.value[3] != null) date.setMonth(d.value[3]); d.date = date; } return xScale(date.getTime()); }); } svg.on("mousemove", function() { var mouse = d3.mouse(this); xScale.distortion(2.5).focus(mouse[0]); bar.call(position); }); However at this point, applying fisheye on the width remains a mystery to me. I have tried several methods like using a fisheye scale for width however it does not work as expected. What i wish to do is to have the width of a bar expand on mouseover, the same way a single vertical bar is singled out on mouseover with the cartesian distortion. Any clues or help will be much appreciated! edit: http://dexter.xumx.me to view the visualisation i am talking about for easier understanding!

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  • Phonegap web view thinks device screen taller than it is - results in offscreen tabbar

    - by Stin
    I have a jQTouch application loaded via server, so all I need to do is display the webpage full screen in PhoneGap for a faux-Native app. Unfortunatley each solution I've tried in PhoneGap has an issue: it thinks the screen size is taller than it is. This resuls in the tabbar that is pinned to the bottom being permantly offscreen and there fore unusable. You should be able to recreate this with my code below and going to the iTabbar online demo. Any thoughts on how to correct this issue? For background, going to the app page in iOS safari works fine, as well as saving the page to the home screen. In both cases the webview stops at the bottom of the screen and the tabbar is therefore viewable. Also, I'm using build.phonegap.com to compile (I'm not compiling locally) I've tried two methods: load the childBrowser plugin and call up the page (with navbar hidden via options) set the following config.xml parameter to prevent phonegap from switching to Safari, and then just load the link (preferable as it's cleaner in my mind. I've pasted my index.html and config.xml below) Details on the config.xml paramater: Open all links in WebView stay-in-webview with values true or false example: <preference name="stay-in-webview" value="true" /> if set to true, all links (even with target set to blank) will open in the app's webview only use this preference if you want pages from your server to take over your entire app default is false (Source: https://build.phonegap.com/docs/config-xml) my index.html: <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN" "http://www.w3.org/TR/html4/strict.dtd"> <html> <head> <meta http-equiv="Content-type" content="text/html;charset=utf-8"> <title>MyApp</title> <script src="phonegap.js"></script> </head> <body> <p><a href="http://www.itabbar.com/itabbar/demo.html#home">Launch iTabbar</a></p> </body> </html> my config.xml: <?xml version="1.0" encoding="UTF-8" ?> <widget xmlns = "http://www.w3.org/ns/widgets" xmlns:gap = "http://phonegap.com/ns/1.0" id = "com.phonegap.myapp" versionCode="10" version = "1.0.0"> <!-- versionCode is optional and Android only --> <name>MyApp</name> <description> My app is... </description> <author href="https://myurl.com" email="[email protected]"> me </author> <preference name="stay-in-webview" value="true" /> </widget>

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  • IQueryable and lazy loading

    - by Nelson
    I'm having a hard time determining the best way to handle this... With Entity Framework (and L2S), LINQ queries return IQueryable. I have read various opinions on whether the DAL/BLL should return IQueryable, IEnumerable or IList. Assuming we go with IList, then the query is run immediately and that control is not passed on to the next layer. This makes it easier to unit test, etc. You lose the ability to refine the query at higher levels, but you could simply create another method that allows you to refine the query and still return IList. And there are many more pros/cons. So far so good. Now comes Entity Framework and lazy loading. I am using POCO objects with proxies in .NET 4/VS 2010. In the presentation layer I do: foreach (Order order in bll.GetOrders()) { foreach (OrderLine orderLine in order.OrderLines) { // Do something } } In this case, GetOrders() returns IList so it executes immediately before returning to the PL. But in the next foreach, you have lazy loading which executes multiple SQL queries as it gets all the OrderLines. So basically, the PL is running SQL queries "on demand" in the wrong layer. Is there any sensible way to avoid this? I could turn lazy loading off, but then what's the point of having this "feature" that everyone was complaining EF1 didn't have? And I'll admit it is very useful in many scenarios. So I see several options: Somehow remove all associations in the entities and add methods to return them. This goes against the default EF behavior/code generation and makes it harder to do some composite (multiple entity) LINQ queries. It seems like a step backwards. I vote no. If we have lazy loading anyway which makes it hard to unit test, then go all the way and return IQueryable. You'll have more control farther up the layers. I still don't think this is a good option because IQueryable ties you to L2S, L2E, or your own full implementation of IQueryable. Lazy loading may run queries "on demand", but doesn't tie you to any specific interface. I vote no. Turn off lazy loading. You'll have to handle your associations manually. This could be with eager loading's .Include(). I vote yes in some specific cases. Keep IList and lazy loading. I vote yes in many cases, only due to the troubles with the others. Any other options or suggestions? I haven't found an option that really convinces me.

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  • Is it ok to dynamic cast "this" as a return value?

    - by Panayiotis Karabassis
    This is more of a design question. I have a template class, and I want to add extra methods to it depending on the template type. To practice the DRY principle, I have come up with this pattern (definitions intentionally omitted): template <class T> class BaseVector: public boost::array<T, 3> { protected: BaseVector<T>(const T x, const T y, const T z); public: bool operator == (const Vector<T> &other) const; Vector<T> operator + (const Vector<T> &other) const; Vector<T> operator - (const Vector<T> &other) const; Vector<T> &operator += (const Vector<T> &other) { (*this)[0] += other[0]; (*this)[1] += other[1]; (*this)[2] += other[2]; return *dynamic_cast<Vector<T> * const>(this); } } template <class T> class Vector : public BaseVector<T> { public: Vector<T>(const T x, const T y, const T z) : BaseVector<T>(x, y, z) { } }; template <> class Vector<double> : public BaseVector<double> { public: Vector<double>(const double x, const double y, const double z); Vector<double>(const Vector<int> &other); double norm() const; }; I intend BaseVector to be nothing more than an implementation detail. This works, but I am concerned about operator+=. My question is: is the dynamic cast of the this pointer a code smell? Is there a better way to achieve what I am trying to do (avoid code duplication, and unnecessary casts in the user code)? Or am I safe since, the BaseVector constructor is private?

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  • What is the best practice for adding persistence to an MVC model?

    - by etheros
    I'm in the process of implementing an ultra-light MVC framework in PHP. It seems to be a common opinion that the loading of data from a database, file etc. should be independent of the Model, and I agree. What I'm unsure of is the best way to link this "data layer" into MVC. Datastore interacts with Model //controller public function update() { $model = $this->loadModel('foo'); $data = $this->loadDataStore('foo', $model); $data->loadBar(9); //loads data and populates Model $model->setBar('bar'); $data->save(); //reads data from Model and saves } Controller mediates between Model and Datastore Seems a bit verbose and requires the model to know that a datastore exists. //controller public function update() { $model = $this->loadModel('foo'); $data = $this->loadDataStore('foo'); $model->setDataStore($data); $model->getDataStore->loadBar(9); //loads data and populates Model $model->setBar('bar'); $model->getDataStore->save(); //reads data from Model and saves } Datastore extends Model What happens if we want to save a Model extending a database datastore to a flatfile datastore? //controller public function update() { $model = $this->loadHybrid('foo'); //get_class == Datastore_Database $model->loadBar(9); //loads data and populates $model->setBar('bar'); $model->save(); //saves } Model extends datastore This allows for Model portability, but it seems wrong to extend like this. Further, the datastore cannot make use of any of the Model's methods. //controller extends model public function update() { $model = $this->loadHybrid('foo'); //get_class == Model $model->loadBar(9); //loads data and populates $model->setBar('bar'); $model->save(); //saves } EDIT: Model communicates with DAO //model public function __construct($dao) { $this->dao = $dao; } //model public function setBar($bar) { //a bunch of business logic goes here $this->dao->setBar($bar); } //controller public function update() { $model = $this->loadModel('foo'); $model->setBar('baz'); $model->save(); } Any input on the "best" option - or alternative - is most appreciated.

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  • Java HTTP Request Occasionally Hangs

    - by behrk2
    Hello Everyone, For the majority of the time, my HTTP Requests work with no problem. However, occasionally they will hang. The code that I am using is set up so that if the request succeeds (with a response code of 200 or 201), then call screen.requestSucceeded(). If the request fails, then call screen.requestFailed(). When the request hangs, however, it does so before one of the above methods are called. Is there something wrong with my code? Should I be using some sort of best practice to prevent any hanging? The following is my code. I would appreciate any help. Thanks! HttpConnection connection = (HttpConnection) Connector.open(url + connectionParameters); connection.setRequestMethod(method); connection.setRequestProperty("WWW-Authenticate", "OAuth realm=api.netflix.com"); if (method.equals("POST")) { connection.setRequestProperty("Content-type", "application/x-www-form-urlencoded"); } int responseCode = connection.getResponseCode(); System.out.println("RESPONSE CODE: " + responseCode); if (connection instanceof HttpsConnection) { HttpsConnection secureConnection = (HttpsConnection) connection; String issuer = secureConnection.getSecurityInfo() .getServerCertificate().getIssuer(); UiApplication.getUiApplication().invokeLater( new DialogRunner( "Secure Connection! Certificate issued by: " + issuer)); } if (responseCode != 200 && responseCode != 201) { screen.requestFailed("Unexpected response code: " + responseCode); connection.close(); return; } String contentType = connection.getHeaderField("Content-type"); ByteArrayOutputStream baos = new ByteArrayOutputStream(); InputStream responseData = connection.openInputStream(); byte[] buffer = new byte[20000]; int bytesRead = 0; while ((bytesRead = responseData.read(buffer)) > 0) { baos.write(buffer, 0, bytesRead); } baos.close(); connection.close(); screen.requestSucceeded(baos.toByteArray(), contentType); } catch (IOException ex) { screen.requestFailed(ex.toString()); }

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  • How to do a search from a list with non-prefix keywords

    - by aNui
    First of all, sorry if my english or my post got any mistakes. I am programming a program to search the name from the list and I need to find them if the keyword is not in front of the names (that's what I mean non-prefix) e.g. if I my list is the music instruments and I type "guit" to the search textbox. It should find the names "Guitar, Guitarrón, Acoustic Guitar, Bass Guitar, ..." or something like this Longdo Dictionary's search suggestion. here is my simple and stupid algorithm (that's all I can do) const int SEARCHROWLIMIT = 30; private string[] DoSearch(string Input, string[] ListToSearch) { List<string> FoundNames = new List<string>(); int max = 0; bool over = false; for (int k = 0; !over; k++) { foreach (string item in ListToSearch) { max = (max > item.Length) ? max : item.Length; if (k > item.Length) continue; if (k >= max) { over = true; break; } if (!Input.Equals("Search") && item.Substring(k, item.Length - k).StartsWith(Input, StringComparison.OrdinalIgnoreCase)) { bool exist = false; int i = 0; while (!exist && i < FoundNames.Count) { if (item.Equals(FoundNames[i])) { exist = true; break; } i++; } if (!exist && FoundNames.Count < SEARCHROWLIMIT) FoundNames.Add(item); else if (FoundNames.Count >= SEARCHROWLIMIT) over = true; } } } return FoundNames.ToArray(); } I think this algorithm is too slow for a large number of names and after several trial-and-error, I decided to add SEARCHROWLIMIT to breaks the operation And I also think there're some readymade methods that can do that. And another problem is I need to search music instruments by a category like strings, percussions, ... and by the country of origins. So I need to search them with filter by type and country. please help me. P.S. Me and my friends are just student from Thailand and developing the project to compete in Microsoft Imagine Cup 2010 and please become fan on our facebook page [KRATIB][3]. And we're so sorry we don't have much information in English but you can talk to us in English.

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  • Which programming language to choose? (for a specific problem/domain, details inside)

    - by Bijan
    I am building a trading portfolio management system that is responsible for production, optimization, and simulation of non-high frequency trading portfolios (dealing with 1min or 3min bars of data, not tick data). I plan on employing Amazon web services to take on the entire load of the application. I have four choices that I am considering as language. a) Java b) C++ c) C# d) Python Here is the scope of the extremes of the project scope. This isn't how it will be, maybe ever, but it's within the scope of the requirements: Weekly simulation of 10,000,000 trading systems. (Each trading system is expected to have its own data mining methods, including feature selection algorithms which are extremely computationally-expensive. Imagine 500-5000 features using wrappers. These are not run often by any means, but it's still a consideration) Real-time production of portfolio w/ 100,000 trading strategies Taking in 1 min or 3 min data from every stock/futures market around the globe (approx 100,000) Portfolio optimization of portfolios with up to 100,000 strategies. (rather intensive algorithm) Speed is a concern, but I believe that Java can handle the load. I just want to make sure that Java CAN handle the above requirements comfortably. I don't want to do the project in C++, but I will if it's required. The reason C# is on there is because I thought it was a good alternative to Java, even though I don't like Windows at all and would prefer Java if all things are the same. Python - I've read somethings on PyPy and pyscho that claim python can be optimized with JIT compiling to run at near C-like speeds.... That's pretty much the only reason it is on this list, besides that fact that Python is a great language and would probably be the most enjoyable language to code in, which is not a factor at all for this project, but a perk. To sum up: - real time production - weekly simulations of a large number of systems - weekly/monthly optimizations of portfolios - large numbers of connections to collect data from There is no dealing with millisecond or even second based trades. The only consideration is if Java can possibly deal with this kind of load when spread out of a necessary amount of EC2 servers. Thank you guys so much for your wisdom.

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  • Java program has errors, 80 lines of code

    - by user2961687
    I have a problem with a program. It contains a lot of errors in Eclipse. Sorry for my english and thank you in advance. Here is the task: I. Declare a class that contains private fields Jam: String taste, double weight Create constructors containing variables as parameters: (String taste, double weight), (double weight), (String taste). Parameters constructors should initialize class fields. In case the constructor does not provide the necessary parameter, it must be assumed that the field taste must have the value "No Name" and weight - 100.0. Introduce the use of all constructors creating objects that represent three kinds of jams. Note: it must be assumed that the only constructor with two parameters can be assigned to fields of the class. Declare a class Jar that contains the field Jam jam, a dedicated constructor initiating all declared fields and methods: open close isItOpen Next, create an object of class Jar and fill it with the selected type of jam, operations repeat for all the kinds of jams. This is my code this far: public class App { public static void main(String[] args) { Jam strawberry = new Jam("strawberry", 20.45); Jam raspberry = new Jam(40.50); Jam peach = new Jam("peach"); Jar jar_1 = new Jar(); Jar jar_2 = new Jar(); Jar jar_3 = new Jar(); jar_1.open(); jar_1.fillIn(strawberry); jar_2.fillIn(peach); jar_3.fillIn(raspberry); } } class Jam { String taste; double weight; public Jam(String taste, double weight) { this.taste = taste; this.weight = weight; } public Jam(double weight) { this.taste = "No name"; this.weight = weight; } public Jam(String taste) { this.taste = taste; this.weight = 100.0; } } class Jar { public Jam Jam = new Jam(); private String state_jar; public Jar() { Jam.weight = 0; Jam.taste = ""; state_jar = "closed"; } public static String open() { state_jar = open; return state_jar; } public static String close() { state_jar = "closed"; return state_jar; } public static boolean isItOpen() { return state_jar; } public void fillIn(Jam jam) { if (isItOpen == false) open(); this.Jam.weight = jam.weight; this.Jam.taste = jam.taste; this.Jam.close(); } }

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  • What is the most effective way to test for combined keyboard arrow direction in ActionScript 3.0?

    - by Relee
    I need to monitor the direction a user is indicating using the four directional arrow keys on a keyboard in ActionScript 3.0 and I want to know the most efficient and effective way to do this. I've got several ideas of how to do it, and I'm not sure which would be best. I've found that when tracking Keyboard.KEY_DOWN events, the event repeats as long as the key is down, so the event function is repeated as well. This broke the method I had originally chosen to use, and the methods I've been able to think of require a lot of comparison operators. The best way I've been able to think of would be to use bitwise operators on a uint variable. Here's what I'm thinking var _direction:uint = 0x0; // The Current Direction That's the current direction variable. In the Keyboard.KEY_DOWN event handler I'll have it check what key is down, and use a bitwise AND operation to see if it's already toggled on, and if it's not, I'll add it in using basic addition. So, up would be 0x1 and down would be 0x2 and both up and down would be 0x3, for example. It would look something like this: private function keyDownHandler(e:KeyboardEvent):void { switch(e.keyCode) { case Keyboard.UP: if(!(_direction & 0x1)) _direction += 0x1; break; case Keyboard.DOWN: if(!(_direction & 0x2)) _direction += 0x2; break; // And So On... } } The keyUpHandler wouldn't need the if operation since it only triggers once when the key goes up, instead of repeating. I'll be able to test the current direction by using a switch statement labeled with numbers from 0 to 15 for the sixteen possible combinations. That should work, but it doesn't seem terribly elegant to me, given all of the if statements in the repeating keyDown event handler, and the huge switch. private function checkDirection():void { switch(_direction) { case 0: // Center break; case 1: // Up break; case 2: // Down break; case 3: // Up and Down break; case 4: // Left break; // And So On... } } Is there a better way to do this?

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