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• Direct flow depending on incoming dynamic type

  - by Improfane

  I have a listener class that accepts GUI change events in one method. The incoming event objects have a superclass of a type of GUI Event, the behaviour should depend on the dynamic type of the incoming variable. I wanted to do do lots of methods like: handleGUIEvent(EventChangedX event) handleGUIEvent(EventChangedY event) I am using a single event listener and receiving objects of various types but the behaviour should be different for each. What would you do? I do not want to use a switch statement as this would get unmaintainable.

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• How SqlDataAdapter works internally?

  - by tigrou

  I wonder how SqlDataAdapter works internally, especially when using UpdateCommand for updating a huge DataTable (since it's usually a lot faster that just sending sql statements from a loop). Here is some idea I have in mind : It creates a prepared sql statement (using SqlCommand.Prepare()) with CommandText filled and sql parameters initialized with correct sql types. Then, it loops on datarows that need to be updated, and for each record, it updates parameters values, and call SqlCommand.ExecuteNonQuery(). It creates a bunch of SqlCommand objects with everything filled inside (CommandText and sql parameters). Several SqlCommands at once are then batched to the server (depending of UpdateBatchSize). It uses some special, low level or undocumented sql driver instructions that allow to perform an update on several rows in a effecient way (rows to update would need to be provided using a special data format and a the same sql query (UpdateCommand here) would be executed against each of these rows).

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• How do I validate that my the openid.op_endpoint when a request is completed.

  - by Sam Saffron

  I have an Open ID based authentication system on my site. Occasionally users will have an account registered under [email protected] and they will attempt to login using the google open id provider https://www.google.com/accounts/o8/id, in this case I would like to automatically associate the account and log them in. When the process is done I get a payload from somewhere claiming that openid.op_endpoint=https://www.google.com/accounts/o8/id. My question: Can I trust openid.op_endpoint to be correct? Can this be spoofed somehow by a malicious openid provider? For illustration, lets say someone types in http://evil.org as their openid provider, can I somehow end up getting a request back that claims openid.op_endpoint is google? Do I need to store extra information against the nonce to validate? The spec is kind of tricky to understand

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• Store database, good pattern for simultaneous access

  - by dygi

  I am kinda new to database designing so i ask for some advices or some kind of a good pattern. The situation is that, there is one database, few tables and many users. How should i design the database, or / and which types of queries should i use, to make it work, if users can interact with the database simultaneously? I mean, they have access to and can change the same set of data. I was thinking about transactions, but I am not sure, if that is the right / good / the only solution. I will appreciate some google keywords too.

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• Fallback to another existing MIME type when the required is missing in Rails

  - by fifigyuri

  I want to extend the existing supported HTML type of my site by support for iPhone. For this I registered a new MIME type. I created a layout for iphone and also converted some of the html views to iphone version. However, I did not convert all of the html.erb files. I do not see the reason to convert all views, some of them should not change, some partials simply just remain the same. I guess there should be a solution for this case. I tried to search for ways how to fallback to an existing format, but did not find any answer. Does a way to define fallback for MIME types in Rails exist? How does it work? If it doesn't exist and thus I wanted to solve the issue not the right way, what could simply solve the task of extending an existing site by another format? Thanks for your suggestions.

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• How do i get a document index so i can delete with lucene?

  - by acidzombie24

  Basically i am doing this I think i'll set the document id as the thread id on my site (even if some types of thread wont be searched). So i can search by thread id but i am clue less of how to delete. I found pages that say use the document index and i need to optimize or close before changes take effect but i dont know how to get the document index. How do i? Also i seen one that said to use IndexWriter to delete but i couldnt figure out how to do it with that either.

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• Credit Card checksums and validations that do not require connection to the financial institution

  - by cjavapro

  The validations I know of are: Checksum the whole card number should add up to zero. (range is 0-9) Check the first digit(s) against the card type Check the length against the card type Check the CCV length against the card type (I think all the major types are 3 anyway) Of course make sure it is accepted card type as well as non expired. Are there any other validations :) (I expect many folks did not know about all of these) The reason I ask is because I overheard there was one to checksum number against expiration or CCV.. I just wanted to check.

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• Data structure for unrooted trees

  - by Esmond

  I'm having problems figuring out how to build an unrooted tree with weighted edges and what data structure to store such a tree. An example of an unrooted tree would be like the one here: http://www.bio.davidson.edu/courses/GENOMICS/seq/unrooted.gif The problem i am having is the leaves would only have 1 link to the internal nodes and the internal nodes would have 3 links(the internal nodes would have 2 children and a link to another internal node). Do i have to distinguish between the 2 different kinds of nodes or can i have one class having the function of both types of nodes?

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• Getting started with C++ ( the paradigm shift from Python )

  - by orokusaki

  I want to learn C++ so that i can develop C++ Python modules for server-related stuff. I'm a purely dynamic languages developer (Python, PHP, Ruby, etc). I want to learn a fast language, and if I'm going to do this, I'd rather learn a really fast language like C++. Before I even get started though, I understand that suddenly working with static types, a different syntax, and compiling code will be quite the paradigm shift. Is there any advice that a C++ dev who also has dynamic languages experience can give me to me to help me make that shift faster?

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• Passing message over network

  - by Sylvestre Equy

  Hi, I'm currently trying to develop a message-oriented networking framework and I'm a bit stuck on the internal mechanism. Here are the problematic interfaces : public interface IMessage { } public class Connection { public void Subscribe<TMessage>(Action<TMessage> messageCallback); public void Send<TMessage>(TMessage message); } The Send method does not seem complicated, though the mechanism behind Subscribe seems a bit more painful. Obviously when receiving a message on one end of the connection, I'll have to invoke the appropriate delegate. Do you have any advice on how to read messages and easily detect their types ? By the way, I'd like to avoid to use MSMQ.

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• Securing input of private / protected methods?

  - by ts

  Hello, normally, all sane developers are trying to secure input of all public methods (casting to proper types, validating, sanitizing etc.) My question is: are you in your code validating also parameters passed to protected / private methods? In my opinion it is not necessary, if you securize properly parameters of public methods and return values from outside (other classes, db, user input etc...). But I am constantly facing frameworks and apps (ie. prestashop to name one) where validation is often repeated in method call, in method body and once again for securize returned value - which, I think, is creating performace overhead and is also a sign of bad design.

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• sql server db deployment script ignoring constraints etc until commit

  - by Daniel

  Hi all, I am planning on doing a database deployment script for sql server 2005. Currently we have a tool that will run all of the tables, foreign keys, indexes and then data, each of which is located in a separate file with a certain extension (eg. tab, .kci, .fky) and the tool just runs *.tab, *.kci, *.fky into the db etc. Could I possibly combine all of thse into one file and have them run ignoring referential integrity until they are all complete, I would turn it on before we started inserting test data. It is just unmanageable having to maintain 4 or 5 different types of scripts for one table. Are there any issues I should be aware of? Cheers

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• 'Advanced' Console Application

  - by keynesiancross

  Hi all, I'm not sure if this question has been answered elsewhere and I can't seem to find anything through google that isn't a "Hello World" example... I'm coding in C# .NET 4.0. I'm trying to develop a console application that will open, display text, and then wait for the user to input commands, where the commands will run particular business logic. For example: If the user opens the application and types "help", I want to display a number of statements etc etc. I'm not sure how to code the 'event handler' for user input though. Hopefully this makes sense. Any help would be much appreciated! Cheers.

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• Is INT the correct datatype for ABS(CHECKSUM(NEWID()))?

  - by Chad Sellers

  I'm in the process of creating unique customers ID's that is an alternative Id for external use. In the process of adding a new column "cust_uid" with datatype INT for my unique ID's, When I do an INSERT into this new column: Insert Into Customers(cust_uid) Select ABS(CHECKSUM(NEWID())) I get a error: Could not create an acceptable cursor. OLE DB provider "SQLNCLI" for linked server "SHQ2IIS1" returned message "Multiple-step OLE DB operation generated errors. Check each OLE DB status value, if available. No work was done. I've check all data types on both tables and the only things that has changed is the new column in both tables. The update is being done on one Big @$$ table...and for reasons above my pay grade, we would like to have new uid's that are different form the one's that we currently have "so users don't know how many accounts we actually have." Is INT the correct datatype for ABS(CHECKSUM(NEWID())) ?

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• How to analyse Wikipedia article's data base with R?

  - by Tal Galili

  Hi all, This is a "big" question, that I don't know how to start, so I hope some of you can give me a direction. And if this is not a "good" question, I will close the thread with an apology. I wish to go through the database of Wikipedia (let's say the English one), and do statistics. For example, I am interested in how many active editors (which should be defined) Wikipedia had at each point of time (let's say in the last 2 years). I don't know how to build such a database, how to access it, how to know which types of data it has and so on. So my questions are: What tools do I need for this (besides basic R) ? MySQL on my computer? RODBC database connection? How do you start planning for such a project?

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• Alternatives to C++ Reference/Pointer Syntax

  - by Jon Purdy

  What languages other than C and C++ have explicit reference and pointer type qualifiers? People seem to be easily confused by the right-to-left reading order of types, where char*& is "a reference to a pointer to a character", or a "character-pointer reference"; do any languages with explicit references make use of a left-to-right reading order, such as &*char/ref ptr char? I'm working on a little language project, and legibility is one of my key concerns. It seems to me that this is one of those questions to which it's easy for a person but hard for a search engine to provide an answer. Thanks in advance!

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• Beginning with Datampper, Association question

  - by Ian

  I'm just diving into Datamapper (and Sinatra) and have a question about associations. Below are some models I have. This is what I want to implemented. I'm having an issue with Workoutitems and Workout. Workout will be managed separately, but Workoutitems has a single workout associated with each row. Workout - just a list of types of workouts (run, lift, situps, etc) Selected workout - this is the name of a set of workouts, along with notes by the user and trainer. It has a collection of N workoutitems Workoutitems - this takes a workout and a number of repetitions to it that go in the workout set. class Workout include DataMapper::Resource property :id, Serial #PK id property :name, String, :length=50,:required=true # workout name property :description, String, :length=255 #workout description end class Selectedworkout include DataMapper::Resource property :id, Serial property :name, String, :length=50, :required=true property :workout_time, String, :length=20 property :user_notes, String, :length=255 property :coach_notes, String, :length=255 has n, :workoutitems end class Workoutitem include DataMapper::Resource property :id, Serial property :reps, String, :length=50, :required=true belongs_to :selectedworkout end

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• How to call in C# function from Win32 DLL with custom objects

  - by marko

  How to use in C# function from Win32 DLL file made in Delphi. When function parameters are custom delphi objects? Function definition in Delphi: function GetAttrbControls( Code : PChar; InputList: TItemList; var Values : TValArray): Boolean; stdcall; export; Types that use: type TItem = packed record Code : PChar; ItemValue: Variant; end; TItemList = array of TItem; TValArray = array of PChar; Example in C# (doesn't work): [StructLayout(LayoutKind.Sequential)] public class Input { public string Code; public object ItemValue; }; [DllImport("Filename.dll", EntryPoint = "GetValues", CharSet = CharSet.Ansi, ExactSpelling = true, CallingConvention = CallingConvention.Cdecl)] public static extern bool GetValues(string Code, Input[] InputList, ref StringBuilder[] Values);

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• When is porting data from MySQL to CouchDB NOT advisable? Seeking cautionary tales

  - by dan

  I've dabbled in CouchDB and I have pretty good MySQL experience. I've also created one production application that uses both. I like MySQL but I've run into scaling/concurrency issues with MySQL that CouchDB advertises itself as a general solution for. The problem is that I have MySQL based applications that are pretty huge, and I don't really know whether it would be a good idea or not to try to port them over to a CouchDB datastore. I don't want to put in a lot of time and effort only to find out that my application is really not a good fit for CouchDB. Is there any sort of informed consensus on when porting a MySQL based app to CouchDB is NOT advisable? Any cautionary tales? I think CouchDB is really cool and want to use it more. I'd also like to know ahead of time what specific types of data querying scenarios CouchDB is really not good for, or if CouchDB can really replace MySQL for all the applications I create going forward.

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• How to use #ifdef entities as part of functions in header files

  - by Crazyjavahacking

  I would like to ask if it is possible to use the entities defined in #ifdef block in header files. To be clear, I have following code: #ifdef #include <winsock2.h> #define SOCKET_HANDLE SOCKET #define CONNECTION_HANDLE SOCKET #endif SOCKET_HANDLE createServerSocket(const char* hostAddress, short port); I am Java developer and this seems completely fine for me. However compiler has a problem with this. Can you explain why is that code a problem? Also how can I force to compile it. (The idea is to have generic interface and conditional compilation to determine real types according to running platform at compile time.) Thanks

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• How do you manage web navigation info in your application?

  - by Dave

  I’m building an application where different users will have different menu items available to them depending on what they’ve paid for. There will also be multiple levels to the menu hierarchy. What’s the best approach to this problem? I’m assuming I need a database table that represents the menu hierarchy, including the parent-child relationships of the nodes in the navigation as well as the sorting of the items. Then another table which I use to manage whether a user is authorized to access a particular item in that table. When I render the view, I’d reference the menus, and the access rights of the user to output the menu, and I’d also need a function to check that same authorization from each controller in case a user manually types in a URL of a controller they’re not supposed to have access to. Is this the right approach? Any suggestions for caching this to prevent the constant look-ups of this type of info? I’m open to any suggestions on how you may have approached this type of requirement.

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• Why am I getting a TypeError when looping?

  - by Lee Crabtree

  I'm working on a Python extension module, and one of my little test scripts is doing something strange, viz.: x_max, y_max, z_max = m.size for x in xrange(x_max): for y in xrange(y_max): for z in xrange(z_max): #do my stuff What makes no sense is that the loop gets to the end of the first 'z' iteration, then throws a TypeError, stating that "an integer is required". If I put a try...except TypeError around it and check the types of x, y, and z, they all come back as < type 'int' . Am I missing something here?

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• Documented process for using facebook connect for the iPhone to upload photos

  - by Corey Floyd

  After looking I did come accross this post on the facebook forums: link They are feeding the facebook object a UIImage. That seems logical, but where is this documented? The API documentation is generalized to all platforms. Where are the iPhone specific requirements for arguments and their data types? Thanks **Update***** I still have not came across any API docs pertaining to Cocoa. I did, however, gather the information I needed by piecing together forum information, Facebook sample code, and some glue. Hopefully they'll issue something a little more concrete over the next few months.

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• Problem when trying to define Show for my Point3D type in Haskell

  - by devoured elysium

  I am trying to define Show for my Point3D type: type Point3D = (Integer, Integer, Integer) instance Show Point3D where show (x,y,z) = "<" ++ (show x) ++ "," ++ (show y) ++ "," ++ (show z) ++ ">" yet I must be missing something in the sintax, as I am always getting an error: Illegal instance declaration for `Show Point3D' (All instance types must be of the form (T t1 ... tn) where T is not a synonym. Use -XTypeSynonymInstances if you want to disable this.) In the instance declaration for `Show Point3D' What am I doing wrong?

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• How to get a dynamic attribute name in cfloop over query in ColdFusion

  - by Kip

  I'm inside a cfloop over a query. I want to get an attribute, but I won't know what that attribute will be until runtime. Using #qryResult[MyAttr]# fails with the error "Complex object types cannot be converted to simple values." What is the syntax for doing this? Here is a simplified example: <cfquery datasource="TestSource" name="qryResult"> SELECT * FROM MyTable </cfquery> <cfloop query="qryResult"> <cfset MyAttr="autoid" /> <cfoutput> Test 1: #qryResult.autoid# <br/> <!--- succeeds ---> Test 2: #qryResult[MyAttr]# <br/> <!--- fails ---> </cfoutput> </cfloop>

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