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  • What design pattern will you choose ?

    - by MemoryLeak
    I want to design a class, which contains a procedure to achieve a goal. And it must follow some order to make sure the last method, let's say "ExecuteIt", to behave correctly. in such a case, what design patter will you use ? which can make sure that the user must call the public method according some ordering. If you really don't know what I am saying, then can you share me some concept of choosing a design patter, or what will you consider while design a class?

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  • Recovering data from hard disk after an accidental Ubuntu reinstallation

    - by Saurabh Agarwal
    My computer got wiped accidentally due to a fresh Ubuntu installation. Since the drive contains very important data and codes, it would be really great if the same could be recovered. It is a 2TB hard drive which had Ubuntu 10.10 earlier. It now has a Ubuntu 12.04 installed on it (which I understand occupies ~4GB). The machine has been powered off since. The installation was done using a usb with the option where the previous ubuntu installation is removed. Since installation doesn't take a lot of time, I'm inclined to think that the disk wasn't completely formatted and that most of the data is still there. I have no experience with recovery and hence a detailed explanation is very helpful. NOTE: I can arrange an additional 2TB hard disk for copying data. My computer has a fast internet connection and I have other computers connected to the network which I may use to access the previous one as well.

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  • Out-Of-Memory while doing Core Data migration

    - by Kamchatka
    Hello, I'm migrating a CoreData model between two versions of an application. I was storing binary data as blobs in the previous version and I want to take them out of the blobs for performance. My issue is that during the migration it seems that Core Data loads everything into memory which leads to Low Memory Warnings and then to my app being killed. Apple documentation suggests the following : http://developer.apple.com/library/mac/documentation/Cocoa/Conceptual/CoreDataVersioning/Articles/vmCustomizingTheProcess.html#//apple_ref/doc/uid/TP40005510-SW9 However, it seems to rely on the fact that the large objects are applied different mapping. In my case, all the objects are basically the same and the same mapping has to be applied to each of them. I don't see in this case how I could apply their technique. How should I handle a migration with very large objects ?

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  • How to study design patterns?

    - by Alien01
    I have read around 4-5 books on design patterns, but still I dont feel I have come closer to intermediate level in design patterns? How should I go studying design patterns? Is there any best book for design pattern? I know this will come only with experience but there must be some way to master these?

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  • Serializing Data Structures in C

    - by src
    I've recently read three separate books on algorithms and data structures, tcp/ip socket programming, and programming with memory. The book about memory briefly discussed the topic of serializing data structures for the purposes of storing it to disk, or sending it across a network. I can't help but wonder why the the other two books didn't discuss serialization at all. After an unsuccessful web/book search I'm left wondering where I can find a good book/paper/tutorial on serializing data structures in C? Where or how did you learn it?

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  • Splitting Logic, Data, Layout and "Hacks"

    - by fjdumont
    Sure, we all heard of programming patterns such as MVVM, MVC and such. But that isn't really what I'm looking into as Layout, Data and Logic is already pretty much split up (XML-Layout markup, Database, insert your language of choice here). The platform I am developing for is hard to maintain over the updated versions and older OSes. The project significantly grew up over the last few months and dealing with different platform versions really is a pain. For example simply disabling an user interface control for all existing versions took me around 40 lines of code in the logic layer, wrangling around with invocation, delegation, singletons that provide UI handling and so on. Is there a clean way to keep track of those "hacks" by maybe excluding it into separate classes or even packages? Should I overwrite existing framework code in order to handle my requirements correctly? If so, does that concept have a name?

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  • How to expose an entity via alternate keys with spring data rest

    - by dan carter
    Spring-data-rest does a great job exposing entities via their primary key for GET, PUT and DELETE etc. operations. /myentityies/123 It also exposes search operations. /myentities/search/byMyOtherKey?myOtherKey=123 In my case the entities have a number of alternate keys. The systems calling us, will know the objects by these IDs, rather than our internal primary key. Is it possible to expose the objects via another URL and have the GET, PUT and DELETE handled by the built-in spring-data-rest controllers? /myentities/myotherkey/456 We'd like to avoid forcing the calling systems to have to make two requests for each update. I've tried playing with @RestResource path value, but there doesn't seem to be a way to add additional paths.

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  • EAV - is it really bad in all scenarios?

    - by Giedrius
    I'm thinking to use EAV for some of the stuff in one of the projects, but all questions about it in stackoverflow end up to answers calling EAV an anti pattern. But I'm wondering, if is it that wrong in all cases? Let's say shop product entity, it has common features, like name, description, image, price, etc., that take part in logic many places and has (semi)unique features, like watch and beach ball would be described by completely different aspects. So I think EAV would fit for storing those (semi)unique features? All this is assuming, that for showing product list, it is enough info in product table (that means no EAV is involved) and just when showing one product/comparing up to 5 products/etc. data saved using EAV is used. I've seen such approach in Magento commerce and it is quite popular, so may be there are cases, when EAV is reasonable?

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  • C++ include statement required if defining a map in a headerfile.

    - by Justin
    I was doing a project for computer course on programming concepts. This project was to be completed in C++ using Object Oriented designs we learned throughout the course. Anyhow, I have two files symboltable.h and symboltable.cpp. I want to use a map as the data structure so I define it in the private section of the header file. I #include <map> in the cpp file before I #include "symboltable.h". I get several errors from the compiler (MS VS 2008 Pro) when I go to debug/run the program the first of which is: Error 1 error C2146: syntax error : missing ';' before identifier 'table' c:\users\jsmith\documents\visual studio 2008\projects\project2\project2\symboltable.h 22 Project2 To fix this I had to #include <map> in the header file, which to me seems strange. Here are the relevant code files: // symboltable.h #include <map> class SymbolTable { public: SymbolTable() {} void insert(string variable, double value); double lookUp(string variable); void init(); // Added as part of the spec given in the conference area. private: map<string, double> table; // Our container for variables and their values. }; and // symboltable.cpp #include <map> #include <string> #include <iostream> using namespace std; #include "symboltable.h" void SymbolTable::insert(string variable, double value) { table[variable] = value; // Creates a new map entry, if variable name already exist it overwrites last value. } double SymbolTable::lookUp(string variable) { if(table.find(variable) == table.end()) // Search for the variable, find() returns a position, if thats the end then we didnt find it. throw exception("Error: Uninitialized variable"); else return table[variable]; } void SymbolTable::init() { table.clear(); // Clears the map, removes all elements. }

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  • Game planning and software design? I feel that UML is not convenient

    - by user1542
    In my university, they always emphasize and hype about UML design and stuff, in which I feel it is not going to work well with game structure design. Now, I just want a professional advice on how should I begin my game designing? The story is I have some skill in programming and have done many minor game such as getting some 2D platformer working to some extend. The problems that I find about my program is the poor quality design. After coding for a while, things start to break down due to poor planning (When I add new feature, it tends to make me have to recode the whole program). However, to plan everything out without a single design flaw is a bit too ideal. Therefore, any advice to how should I plan my game? How should I put it into visible pictures, so that me and my friends are able to overview the designs? I planned to start coding a game with my friend. This is going to be my first teamwork, so any professional advices would be a pleasure. Is there any other alternatives than UML? Another question is how does "prototyping" normally looks like?

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  • Connecting data to a GUI - OOP

    - by tau
    I have an application with several graphs and tables on it. I worked fast and just made classes like Graph and Table that each contained a request object (pseudo-code): class Graph { private request; public function setDateRange(dateRange) { request.setDateRange(dateRange); } public function refresh() { request.getData(function() { //refresh the display }); } } Upon a GUI event (say, someone changes the date range dropdown), I'd just call the setters on the Graph instance and then refresh it. Well, when I added other GUI elements like tables and whatnot, they all basically had similar methods (setDateRange and other things common to the request). What are some more elegant OOP ways of doing this? The application is very simple and I don't want to over-architect it, but I also don't want to have a bunch of classes with basically the same methods that are just routing to a request object. I also don't want to set up each GUI class as inheriting from the request class, but I'm open to any ideas really.

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  • Would this data requirement suit a Document -Oriented database?

    - by codecowboy
    I have a requirement to allow users to fill in journal/diary entries per day. I want to provide a handful of known journal templates with x columns to fill in. An example might be a thought diary; a user has to record a thought in one column, describe the situation, rate how they felt etc. The other requirement is that a user should be able to create their own diary templates. They might have a need for a 10 column diary entry per day and might need to rate some aspect out of 50 instead of 10. In an RDBMS, I can see this getting quite complicated. I could have individual tables for my known templates as the fields will be fixed. But for custom diary templates I imagine I would would need a table storing custom_field_types (the diary columns), a table storing entries referencing their field types (custom_entries) and then a third custom_diary table which would store rows matching custom_entries to diaries. Leaving performance / scaling aside, would it be any simpler or make more sense to use a document oriented database like MongoDB to store this data? This is for a web application which might later need an API for mobile devices.

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  • Data structure supporting the following operations

    - by 500865
    I'm looking for a data structure for working with a set of data which is most efficient to do the following : Check whether an item has been categorized or not. (The categorized and uncategorized set are disjoint sets). Get the category of an item. Get all the items in a particular category. Get all the uncategorized items. Remove a particular item from the data set. I was thinking of having a Dictionary<String, Set<String>> to hold all the items in a given category, but that doesn't solve 2.

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  • Need design ideas generators.

    - by Clubspy
    Hello guys I am a web developer and sometimes I have to do some design myself for my customers but design actually is not my best thing to do. I am looking for a program that can help me getting fast and reliable design ideas but I am not looking for code generator like Artisteer. Actually design is a hard task and my designs always look ugly and messy.

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  • Suggestions for opening the Rails toolbox to design a challenge game?

    - by keruilin
    How would you suggest designing a challenge system as part of a food-eating game so that it's automated as possible? All RoR tools, design patterns and logic are at your disposal (e.g., admin consoles, crontab, arch, etc.). Prize goes to whoever can suggest the simplest and most-automated design! Here are the requirements: User has many challenges. Badge has many challenges. (A unique badge is awarded for each challenge won.) Only one challenge can run at a time. Each challenge has a limited number of days that it runs. For example, one challenge can run 3 days, while another runs 7 days. Challenges can be seasonal. For example, "Eat 13 Pumpkins" only runs during the Fall. New challenges are added to the game on an ongoing basis. For example, a new challenge every week. Each challenge has a certain probability of being selected to run. For example, "Eat 10 Pies" challenge has 10% chance of being selected to run. As each new challenge is added to the database, I want the probabilities of running to change dynamically. I want to avoid the scenario where I'm manually updating a database field just to change the probability from 10% to 5%, for example. Challenges act like Easter eggs. Challenge icons pop-up at different places on the webpage. User is awarded a badge for successfully completing a challenge, but only when it's active. There is some wait time between each challenge. Between 1 and 7 days. Which wait time is random, but the probability of the wait time being short is high and the probability of it being a long wait time is low.

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  • What makes my code DDD (domain-driven design) qualified?

    - by oykuo
    Hi All, I'm new to DDD and am thinking about using this design technique in my project. However, what strikes me about DDD is that how basic the idea is. Unlike other design techniques such as MVC and TDD, it doesn't seems to contain any ground breaking ideas. For example, I'm sure some of you will have the same feeling that the idea of root aggregates and repositories are nothing new because when you are was writing MVC web applications you have to have one single master object (i.e. the root aggregate) that contain other minor objects (i.e. value objects and entities) in the model layer in order to send data to a strongly typed view. To me, the only new idea in DDD is probably the "Smart" entities (i.e. you are supposed to have business rules on root aggregates) Separation between value object, root aggregate and entities. Can anyone tell me if I have missed out anything here? If that's all there is to DDD, if I update one of my existing MVC application with the above 2 new ideas, can I claim it's an TDD, MVC and DDD applcation?

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  • UPOS RFIDScanner data format

    - by Robert Snyder
    A lot of work that I do currently is based in the OPOS/UPOS world. My company has a device that can read 13.56Mhz tags (RFID), Smart Cards, and Mag Stripe cards. Up until somewhat recently I have only been working with RFID for a very specific scenario. That was to read UltraLight C and Desfire cards. These cards were all setup very specifically so that I could take the data read from those cards and force it into a MSR track2 format. The past couple of weeks, however, I have been working on reading RFID credit cards (since I have a Visa card I've been using mine), and Smart Card credit cards. (The visa card I have has both) In learning how to communicate with SmartCard and reading ISO7816 and EMVCO documents I became a little more familiar with how info is stored. But now I have a question regarding UPOS. The RFID data on my Visa is stored (and read) very similar to how the data is stored and read from the Smart Card on my Visa. Cool. Well in the UPOS spec for SmartCardRW the ReadData method returns a byte array. That's cool, I can just return all that data and then parse it as my heart desires. The RFID though has a LinkedList of Tags. Well this makes sense in terms of my Visa card (reminds me of a question I have in regards to SmartCard, but that is for another question) but what about ULC and Desfire, or for that matter any Mifare card. Pages, Files, Purses don't exactly fit the Tag profile. For instance lets just say I read pages 4-12 on my ULC card. Each page I read is 4 bytes long. Does this mean I have 9 tags in my LinkedList? Is my Tag id the page number? Or then how does that translate to Desfire? I open application 123456 and read file 1 and file 2, Do I have 2 tags? and if so what is my tag id? At least with my Visa I think that I have to use the Tag id (ex 5F24 for my expiration date) and value of {0x15, 0x10, 0x31} Part of me says yes..that makes sense. Another part of me says, "well if that is the case then why doesn't SmartCardRW have Tags?" So that is my question. How do I format my data from those different types of media? or is that the job of my Control Object (the application)? Is so how does it know? The only protocols I have are: // Summary: // Enumerates the available predefined RFID tag protocols the device supports. [Flags] public enum RFIDProtocols { EpcClass0 = 1, RFIDSdt0Plus = 2, EpcClass1 = 4, EpcClass1Gen2 = 8, EpcClass2 = 16, Iso14443A = 4096, Iso14443B = 8192, Iso15693 = 12288, Iso180006B = 16384, Other = 16777216, All = 1073741824, } If I use that well all of my cards that I have are all Iso14443A. I use the ATQA and the SAK to know what type of card I really have. There is no RFID property that lets me specify that. So I'm lost.

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  • Integrating WIF with WCF Data Services

    - by cibrax
    A time ago I discussed how a custom REST Starter kit interceptor could be used to parse a SAML token in the Http Authorization header and wrap that into a ClaimsPrincipal that the WCF services could use. The thing is that code was initially created for Geneva framework, so it got deprecated quickly. I recently needed that piece of code for one of projects where I am currently working on so I decided to update it for WIF. As this interceptor can be injected in any host for WCF REST services, also represents an excellent solution for integrating claim-based security into WCF Data Services (previously known as ADO.NET Data Services). The interceptor basically expects a SAML token in the Authorization header. If a token is found, it is parsed and a new ClaimsPrincipal is initialized and injected in the WCF authorization context. public class SamlAuthenticationInterceptor : RequestInterceptor {   SecurityTokenHandlerCollection handlers;   public SamlAuthenticationInterceptor()     : base(false)   {     this.handlers = FederatedAuthentication.ServiceConfiguration.SecurityTokenHandlers;   }   public override void ProcessRequest(ref RequestContext requestContext)   {     SecurityToken token = ExtractCredentials(requestContext.RequestMessage);     if (token != null)     {       ClaimsIdentityCollection claims = handlers.ValidateToken(token);       var principal = new ClaimsPrincipal(claims);       InitializeSecurityContext(requestContext.RequestMessage, principal);     }     else     {       DenyAccess(ref requestContext);     }   }   private void DenyAccess(ref RequestContext requestContext)   {     Message reply = Message.CreateMessage(MessageVersion.None, null);     HttpResponseMessageProperty responseProperty = new HttpResponseMessageProperty() { StatusCode = HttpStatusCode.Unauthorized };     responseProperty.Headers.Add("WWW-Authenticate",           String.Format("Basic realm=\"{0}\"", ""));     reply.Properties[HttpResponseMessageProperty.Name] = responseProperty;     requestContext.Reply(reply);     requestContext = null;   }   private SecurityToken ExtractCredentials(Message requestMessage)   {     HttpRequestMessageProperty request = (HttpRequestMessageProperty)  requestMessage.Properties[HttpRequestMessageProperty.Name];     string authHeader = request.Headers["Authorization"];     if (authHeader != null && authHeader.Contains("<saml"))     {       XmlTextReader xmlReader = new XmlTextReader(new StringReader(authHeader));       var col = SecurityTokenHandlerCollection.CreateDefaultSecurityTokenHandlerCollection();       SecurityToken token = col.ReadToken(xmlReader);                                        return token;     }     return null;   }   private void InitializeSecurityContext(Message request, IPrincipal principal)   {     List<IAuthorizationPolicy> policies = new List<IAuthorizationPolicy>();     policies.Add(new PrincipalAuthorizationPolicy(principal));     ServiceSecurityContext securityContext = new ServiceSecurityContext(policies.AsReadOnly());     if (request.Properties.Security != null)     {       request.Properties.Security.ServiceSecurityContext = securityContext;     }     else     {       request.Properties.Security = new SecurityMessageProperty() { ServiceSecurityContext = securityContext };      }    }    class PrincipalAuthorizationPolicy : IAuthorizationPolicy    {      string id = Guid.NewGuid().ToString();      IPrincipal user;      public PrincipalAuthorizationPolicy(IPrincipal user)      {        this.user = user;      }      public ClaimSet Issuer      {        get { return ClaimSet.System; }      }      public string Id      {        get { return this.id; }      }      public bool Evaluate(EvaluationContext evaluationContext, ref object state)      {        evaluationContext.AddClaimSet(this, new DefaultClaimSet(System.IdentityModel.Claims.Claim.CreateNameClaim(user.Identity.Name)));        evaluationContext.Properties["Identities"] = new List<IIdentity>(new IIdentity[] { user.Identity });        evaluationContext.Properties["Principal"] = user;        return true;      }    } A WCF Data Service, as any other WCF Service, contains a service host where this interceptor can be injected. The following code illustrates how that can be done in the “svc” file. <%@ ServiceHost Language="C#" Debug="true" Service="ContactsDataService"                 Factory="AppServiceHostFactory" %> using System; using System.ServiceModel; using System.ServiceModel.Activation; using Microsoft.ServiceModel.Web; class AppServiceHostFactory : ServiceHostFactory {    protected override ServiceHost CreateServiceHost(Type serviceType, Uri[] baseAddresses)   {     WebServiceHost2 result = new WebServiceHost2(serviceType, true, baseAddresses);     result.Interceptors.Add(new SamlAuthenticationInterceptor());                 return result;   } } WCF Data Services includes an specific WCF host of out the box (DataServiceHost). However, the service is not affected at all if you replace it with a custom one as I am doing in the code above (WebServiceHost2 is part of the REST Starter kit). Finally, the client application needs to pass the SAML token somehow to the data service. In case you are using any Http client library for consuming the data service, that’s easy to do, you only need to include the SAML token as part of the “Authorization” header. If you are using the auto-generated data service proxy, a little piece of code is needed to inject a SAML token into the DataServiceContext instance. That class provides an event “SendingRequest” that any client application can leverage to include custom code that modified the Http request before it is sent to the service. So, you can easily create an extension method for the DataServiceContext that negotiates the SAML token with an existing STS, and adds that token as part of the “Authorization” header. public static class DataServiceContextExtensions {        public static void ConfigureFederatedCredentials(this DataServiceContext context, string baseStsAddress, string realm)   {     string address = string.Format(STSAddressFormat, baseStsAddress, realm);                  string token = NegotiateSecurityToken(address);     context.SendingRequest += (source, args) =>     {       args.RequestHeaders.Add("Authorization", token);     };   } private string NegotiateSecurityToken(string address) { } } I left the NegociateSecurityToken method empty for this extension as it depends pretty much on how you are negotiating tokens from an existing STS. In case you want to end-to-end REST solution that involves an Http endpoint for the STS, you should definitely take a look at the Thinktecture starter STS project in codeplex.

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  • Class hierarchy problem in this social network model

    - by Gerenuk
    I'm trying to design a class system for a social network data model - basically a link/object system. Now I have roughly the following structure (simplified and only relevant methods shown) class Data: "used to handle the data with mongodb" "can link, unlink data and also return other linked data" "is basically a proxy object that only stores _id and accesses mongodb on requests" "it looks like {_id: ..., _out: [id1, id2,...], _inc: [id3, id4, ...]}" def get_node(self, id) "create a new Data object from the underlying mongodb" "each data object can potentially create a reference object to new mongo data" "this is needed when the data returns the linked objects" class Node: """ this class proxies linking calls to .data it includes additional network logic operations whereas Data only contains a basic database solution """ def __init__(self, data): "the infrastructure realization is stored as composition by an included object data" "Node bascially proxies most calls to the infrastructure object data" def get_node(self, data): "creates a new object of class Object or Link depending on data" class Object(Node): "can have multiple connections to Link" class Link(Node): "has one 'in' and one 'out' connection to an Object" This system is working, however maybe wouldn't work outside Python. Note that after reading links Now I have two questions here: 1) I want to infrastructure of the data storage to be replacable. Earlier I had Data as a superclass of Node so that it provided the neccessary calls. But (without dirty Python tricks) you cannot replace the superclass dynamically. Is using composition therefore recommended? The drawback is that I have to proxy most calls (link, unlink etc). Any thoughts? 2) The class Node contains the common method .get_node which is used to built new Object or Link instances after reading out the data. Some attribute of data decided whether the object which is only stored by id should be instantiated as an Object or Link class. The problem here is that Node needs to know about Object and Link in advance, which seems dodgy. Do you see a different solution? Both Object and Link need to instantiate one of all possible types depending on what the find in their linked data. Are there any other ideas how to implement a flexible Object/Link structure where the underlying database storage is isolated?

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  • How to disable authentication schemes for WCF Data Services

    - by Schneider
    When I deployed my WCF Data Services to production hosting I started to get the following error (or similar depending on which auth schemes are active): IIS specified authentication schemes 'Basic, Anonymous', but the binding only supports specification of exactly one authentication scheme. Valid authentication schemes are Digest, Negotiate, NTLM, Basic, or Anonymous. Change the IIS settings so that only a single authentication scheme is used. Apparently WCF Data Services (WCF in general?) cannot handle having more than once authentication scheme active. OK so I am aware that I can disable all-but-one authentication scheme on the web application via IIS control panel .... via a support request!! Is there a way to specify a single authentication scheme on a per-service level in the web.config? I thought this might be as straight forward as making a change to <system.serviceModel> but... it turns out that WCF Data Services do not configure themselves in the web config. If you look at the DataService<> class it does not implement a [ServiceContract] hence you cannot refer to it in the <service><endpoint>...which I presume would be needed for changing its configuration via XML. P.S. Our host is using II6, but both solutions for IIS6 & IIS7 appreciated.

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  • Correctly assigning value to a Core Data attribute with an integer data-type

    - by Gordon Fontenot
    I'm missing something here, and feeling like an idiot about it. I'm using a UIPickerView in my app, and I need to assign the row number to a 32-bit integer attribute for a Core Data object. To do this, I am using this method: -(void)pickerView:(UIPickerView *)pickerView didSelectRow:(NSInteger)row inComponent:(NSInteger)component { object.integerValue = row; } This is giving me a warning: warning: passing argument 1 of 'setIntegerValue:' makes pointer from integer without a cast What am I mixing up here? --Edit 1-- Ok, so I can get rid of the warning by changing the method to do the following: NSNumber *number = [NSNumber numberWithInteger:row]; object.integerValue = rating; However, I still get a value of 0 for object.integerValue if I use NSLog to print it out. object.integerValue has a max value of 5, so I print out number instead, and then I'm getting a number above 62,000,000. Which doesn't seem right to me, since there are 5 rows. If I NSLog the row variable, I get a number between 0 and 5. So why do I end up with a completely different number after casting the number to NSNumber? --Edit 2-- Ok, so I'm realizing that there is some fundamental idea that I don't understand. I now understand that the 60 million + number can be cast back to the correct 0-5 number by using integerValue. So, it seems my question is how can I save an integer between 0-5 to the attribute if the NSNumber that is returned is over 60 million? Do I need to be using a different data type?

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  • Doubts About Core Data NSManagedObject Deep Copy

    - by Jigzat
    Hello everyone, I have a situation where I must copy one NSManagedObject from the main context into an editing context. It sounds unnecessary to most people as I have seen in similar situations described in Stackoverflow but I looks like I need it. In my app there are many views in a tab bar and every view handles different information that is related to the other views. I think I need multiple MOCs since the user may jump from tab to tab and leave unsaved changes in some tab but maybe it saves data in some other tab/view so if that happens the changes in the rest of the views are saved without user consent and in the worst case scenario makes the app crash. For adding new information I got away by using an adding MOC and then merging changes in both MOCs but for editing is not that easy. I saw a similar situation here in Stackoverflow but the app crashes since my data model doesn't seem to use NSMutableSet for the relationships (I don't think I have a many-to-many relationship, just one-to-many) I think it can be modified so I can retrieve the relationships as if they were attributes for (NSString *attr in relationships) { [cloned setValue:[source valueForKey:attr] forKey:attr]; } but I don't know how to merge the changes of the cloned and original objects. I think I could just delete the object from the main context, then merge both contexts and save changes in the main context but I don't know if is the right way to do it. I'm also concerned about database integrity since I'm not sure that the inverse relationships will keep the same reference to the cloned object as if it were the original one. Can some one please enlighten me about this?

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  • Binding Data to a TextBlock using Domain Data Source

    - by TFisher
    I have a map with hotspots for each state (done in Expression Blend). I capture each MouseEnter of the state (1 thru 50). I pass that into my Domain Data Source: Dim activebox As Path = TryCast(sender, Path) activebox.Fill = mouseOverColor Dim StateID As Integer = CInt(Right(activebox.Name, 2)) Dim _StateContext As New StateContext myDataGrid.ItemsSource = _StateContext.States _StateContext.Load(_StateContext.GetStateByStateIDQuery(StateID.Text)) The above works fine for a datagrid, listbox and even a dataform. But I created a popup with a stackpanel that has textblocks. popupStatesBox.DataContext = ?????????????? popupStatesBox.IsOpen = True 'popup does open but has no data -- popupStatesBox.xaml <Popup x:Name="popupStatsBox" Margin="8,35,0,8" DataContext="{Binding}" IsOpen="false" Width="268" HorizontalAlignment="Left"> <StackPanel x:Name="Layout" Background="Black"> <TextBlock x:Name="tbState" Text="{Binding StateName /> <TextBlock x:Name="tbAbbrev" Text="{Binding Abbreviation}" /> </StackPanel> </Popup> How do I get the textblocks to display the values from the _StateContext. StackPanel has DataContext but no ItemsSource. What am I missing?

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  • [Smalltalk] Store List of Instruction

    - by Luciano Lorenti
    Hi all, I have a design Problem. i have a Drawer class wich invokes a serie of methods of a kind-of-brush class and i have a predefined shapes which i want to draw. Each shape uses a list of instance methods from the drawer. I can have more than 1 brush object. I want to add custom shapes on runtime in the drawer instance, especifying the list of methods of the new shape. i've created a class method for every predefined shape that returns a BlockClosure with the instruccions. Obviously i have to give to each BlockClosure the brush object as parameter. I imagine a collection with all the BlockClosures in each instance of the Drawer Class. Maybe i can inherit a SequenceableCollection and make a instruccion collection. Each element of the collection it's a instruction and i give the brush object when i instance this new collection. I really don't know the best way to store these steps. (Maybe a shared variable?)

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