Search Results

Search found 19923 results on 797 pages for 'instance variables'.

Page 570/797 | < Previous Page | 566 567 568 569 570 571 572 573 574 575 576 577  | Next Page >

  • validates_uniqueness_of...limiting scope - How do I restrict someone from creating a certain number

    - by bgadoci
    I have the following code: class Like < ActiveRecord::Base belongs_to :site validates_uniqueness_of :ip_address, :scope => [:site_id] end Which limits a person from "liking" a site more than one time based on a remote ip request. Essentially when someone "likes" a site, a record is created in the Likes table and I use a hidden field to request and pass their ip address to the :ip_address column in the like table. With the above code I am limiting the user to one "like" per their ip address. I would like to limit this to a certain number for instance 10. My initial thought was do something like this: validates_uniqueness_of :ip_address, :scope => [:site_id, :limit => 10] But that doesn't seem to work. Is there a simple syntax here that will allow me to do such a thing?

    Read the article

  • What is the point/purpose of Ruby EventMachine, Python Twisted, or JavaScript Node.js?

    - by CCw
    I don't understand what problem these frameworks solve. Are they replacements for a HTTP server like Apache HTTPD, Tomcat, Mongrel, etc? Or are they more? Why might I use them... some real world examples? I've seen endless examples of chat rooms and broadcast services, but don't see how this is any different than, for instance, setting up a Java program to open sockets and dispatch a thread for each request. I think I understand the non-blocking I/O, but I don't understand how that is any different than a multi-threaded web server.

    Read the article

  • Java library for converting Word documents to PDFs or images

    - by mieze
    Hey there What I need to do is convert Microsoft Word .doc files to PDFs or images. This has to occur in Java. I have done a fair bit of investigation already. I've tried Davisor Publishor but it doesn't give me the accuracy that I need - for instance text overlapping in the output document. Adobe has something called LiveCycle. Anyone tried this? It looks quite massive and a bit of overkill (its an "integrated server solution"). Sounds expensive. Saying that, it doesn't have to be free, or cheap. Even if you just know some names, please shout them my way. Many thanks in advance. Doug

    Read the article

  • How to override built-in getattr in Python?

    - by Stephen Gross
    I know how to override an object's getattr() to handle calls to undefined object functions. However, I would like to achieve the same behavior for the builtin getattr() function. For instance, consider code like this: call_some_undefined_function() Normally, that simply produces an error: Traceback (most recent call last): File "<stdin>", line 1, in <module> NameError: name 'call_some_undefined_function' is not defined I want to override getattr() so that I can intercept the call to "call_some_undefined_function()" and figure out what to do. Is this possible? Thanks, --Steve

    Read the article

  • What languages allow cross-platform native executables to be created?

    - by JT
    I'm frustrated to discover that Java lacks an acceptable solution for creating programs that will run via double-click. Other than .NET for Windows, what modern and high-level programming languages can I write code in that can be compiled for various platforms and run as a native/binary in each (Windows, Linux, OSX (optional)) Assuming I wanted to write code in python, for instance, is there a cohesive way that I could distribute my software which wouldn't require users to do anything special to get it to run? I want to write and distribute software for computer-illiterate and Java has turned out to be a real pain in this respect.

    Read the article

  • @@TRANCOUNT and a current connection

    - by AspOnMyNet
    Assume I connect to SQL server 2008 via SQL Server Management Studio ( SSMS ) and open new window W1 by clicking on New Query tab and write the following inside W1: BEGIN TRANSACTION; If I execute this statement 5 times, and then write (inside W1) SELECT @@TRANCOUNT; , then the value returned will be 5. But if I open another window W2 ( inside the same SSMS instance and thus on the same connection ) and write inside W2 SELECT @@TRANCOUNT; then value returned will be 0. @@TRANCOUNT variable returns the number of active transactions for the current connection. Both W1 and W2 windows were opened on the same connection, so shouldn’t ( according to the above quote ) in both W1 and W2 variable @@TRANCOUNT hold the same value? thanx

    Read the article

  • Service locator for generics

    - by vittore
    Hi everyone, I have say a dozen types T which inherit from EntityObject and IDataObject. I have generic the following interface IDataManager<T> where T : EntityObject, IDataObject ... I have also base class for data managers BaseDataManager<T> : IDataManager<T> where T : EntityObject, IDataObject .... And i have particular classes public class Result : EntityObject, IDataObject .... public class ResultDataManager : BaseDataManager<Result> ... I want to implement service locator, which will return instance of IDataManager<T> for T But I stucked how to implement it in a neat way without a lot of castings. Any ideas?

    Read the article

  • Retrieving datatypes from underlying database

    - by H4mm3rHead
    Hi, Im making an application that displays information about an underlying database. The database can be anything, but is typically either Oracle, MSSQL or MySQL. I am trying to extract the datatype but cannot seem to get this right. I have a DbConnection because i dont know whether I need a OleDbConnection or an OdbcConnection. On this connection I make a GetSchema("Columns", "mytablename") query and gets the result back. It seems though that there are some inconsistencies with my datatypes or the query returns different datatypes for the different databases. For instance, in my MSSQL database I query and get an integer back (which seems to be the OleDbType) which I map to a datatype. My varchars is now of type char - no length - and this confuses me a bit. I guess my main question is something like: Is there any way of making a uniform way of extracting datatypes across providers and having an "accurate" representation of the datatype?

    Read the article

  • Text code decoding

    - by Diana Villafane
    Hello. I am an English/Spanish Spanish/English translator. I have been given a job where I have to translate Spanish text messages sent from cell phones. Some of them are in code. I assume each set of figures represents a letter. Is there any website where I can find information on how to decipher the code? For instance, the first message says: ‘0x69 ox61 0x6e 0x70 0x72 0x2e 0x6e 0x65 0x74 0x2f 0x3f 0x64 0x34 0x39 0x31 0x66 0x30 0x37 0x38 0x35 0x35 0x32 0x39 0x62 0x36 0x31 0x31 0x00 Thank you for any help you provide. Diana

    Read the article

  • iPhone 4.0 Screen Resolution and writing robust code...

    - by Magic Bullet Dave
    Does anyone know what will happen with existing apps when they run on the iPhone 4.0 in terms of the new screen resolution? I am assuming, just like developing for the iPad that there should be no hard coded screen resolutions in your code. I'd also like advice on the best way of writing robust code to work well on any device. For instance, detecting the screen resolution is not enough - on the iPad the screen is physically bigger so you can display more items on it. On the new iPhone the screen is the same physical size but higher resolution, so the likely thing is that you wont want to display more items, just higher resolution versions of them. Any help would be useful, Regards Dave EDIT: I have read the other similar posts, I guess what I really would like to know is what is the recommended way to write code for all App Store devices in a robust way so they a) all work b) make best use of the device.

    Read the article

  • Domain Model and Contracts

    - by devoured elysium
    I am modelling a DVD Rental Store: A Client gives its clientNumber to the System. The System checks whenever the given clientNumber is valid. The Client gives the name of the DVD he wants to rent. ... n. ...I will later have to form an association between a new instance of "RentDVD" class concept to the current Client c. My Domain Model is something like: I've made the Contract for the first and second operations as: Preconditions: none Postconditions: there exists a Client c such that c.clientNumber = clientNumber. Now, I don't know if I should form an association between this Client c and the DVDStore(that I intend to use as front-end). If I don't make the association, how will I later be able to "reference" this same Client? Should I be making an association between Client and a different concept? Thanks

    Read the article

  • hibernate Query by primary key

    - by adisembiring
    Hi ... I wanna create query by primary key. Supposed I have class primary key, PersonKey, the properties is name and id. I have Person class, the property is PersonKey, address, DOB. Now, I wanna search person by primary key. First, I create instance of PersonKey, and set the name become: joe, and id become:007 can I get the person by ID, by pass the key variable ??? person.findByKey(someKey); , but the logic do not criteria

    Read the article

  • Sqlalchemy layout with WSGI application

    - by TheDude
    I'm working on writing a small WSGI application using Bottle and SqlAlchemy and am confused on how the "layout" of my application should be in terms of SqlAlchemy. My confusion is with creating engines and sessions. My understanding is that I should only create one engine with the 'create_engine' method. Should I be creating an engine instance in the global namespace in some sort of singleton pattern and creating sessions based off of it? How have you done this in your projects? Any insight would be appreciated. The examples in the documentation dont seem to make this entirely clear (unless I'm missing something obvious). Any thoughts?

    Read the article

  • How to convert code to properly release memory

    - by BankStrong
    I've taken over a code base that has subtle flaws - audio player goes mute, unlogged crashes, odd behavior, etc. I found a way to provoke one instance of the problem and tracked it to this code snippet: NSURL *soundURL = [NSURL fileURLWithPath:[[NSBundle mainBundle] pathForResource:[[soundsToPlay objectAtIndex:count] description] ofType:@"mp3"]]; self.audioPlayer = nil; self.audioPlayer = [[AVAudioPlayer alloc] initWithContentsOfURL:soundURL error:nil]; self.audioPlayer.delegate = self; AudioSessionSetActive(YES); [audioPlayer play]; When I comment out the 2nd line (nil) and add a release to the end, this problem stops. [self.audioPlayer release]; Where do I go from here? Nils are used in a similar fashion throughout the code (and may cause similar problems) - is there a safe way to remove them? I'm new to memory management - how can I discern proper nil usage from bad nil usage?

    Read the article

  • Can't get results from a IQueryable.

    - by StackPointer
    Hi! I have the following code in Linq to Entity: var policy= from pol in conn.Policy where pol.Product.DESCRIPTION=="someProduct" SELECT pol; Then, the table Policy, has some dependencies for a table called Entity. If I do this: foreach(Policy p in policy){ if(!p.Entity.IsLoaded) p.Entity.Load(); IEnumerable<Entity> entities= from ent in p.Entity Where ent.EntityType.DESCRIPTION=="SomeEntityType" select ent; Console.Writeline(entities.ElementAt(0).NAME); } It says, "Object not set to an instance", but if I do: foreach(Policy p in policy){ if(!p.Entity.IsLoaded) p.Entity.Load(); foreach(Entity et in p.Entity)Console.Write(et.NAME); } It works! Can anyone tell me why? Thank you, Best regards.

    Read the article

  • how to translate Haskell into Scalaz?

    - by TOB
    One of my high school students and I are going to try to do a port of Haskell's Parsec parser combinator library into Scala. (It has the advantage over Scala's built-in parsing library that you can pass state around fairly easily because all the parsers are monads.) The first hitch I've come across is trying to figure out how Functor works in scalaz. Can someone explain how to convert this Haskell code: data Reply s u a = Ok a !(State s u) ParseError | Error ParseError instance Functor (Reply s u) where fmap f (Ok x s e) = Ok (f x) s e fmap _ (Error e) = Error e -- XXX into Scala (using Scalaz, I assume). I got as far as sealed abstract class Reply[S, U, A] case class Ok[S, U, A](a: A, state: State[S, U], error: ParseError) extends Reply[S, U, A] case class Error[S, U, A](error: ParseError) extends Reply[S, U, A] and know that I should make Reply extend the scalaz.Functor trait, but I can't figure out how to do that. (Mostly I'm having trouble figuring out what the F[_] parameter does.) Any help appreciated! Thanks, Todd

    Read the article

  • Cannot figure out how to get rid of memory leak

    - by Mark S.
    I'm trying to test for memory leaks in my iphone and I'm not having much luck getting rid of this one. Here is the code that is leaking. - (id)initWithManagedObjectContext:(NSManagedObjectContext *)aMoc delegate:(id)aDelegate runSync:(BOOL)aRunSync { if (self = [super init]) { self.moc = aMoc; self.settingsManager = [[VacaCalcSettingsManager alloc] initWithManagedObjectContext:self.moc]; self.delegate = aDelegate; calendar = [[NSCalendar alloc] initWithCalendarIdentifier:NSGregorianCalendar]; self.runSync = aRunSync; } return self; } It is leaking on the self.settingsManager = [[VacaCalcSettingsManager alloc] initWithManagedObjectContext:self.moc]; line. The self.settingManager instance variable is released in the dealloc method of the class. I'm not sure what other information would be pertinent. Please let me know and I can provide it. Thanks for any assistance. -Mark

    Read the article

  • String.fromCharCode & CharacterSets

    - by jAndy
    Hi Folks, I recently tried to mirror some input within input(text) fields. Using String.fromCharCode(event.which) for instance, translates all 'standard' characters correctly. Well it translates them all to uppercase, but that you can easily catch by looking up the shift key aswell. My Problem is, it can't translate characters like dots, commas, questionmarks etc. First guess was that I have to define a character encoding set, but that does not seem to help. Maybe it'm completly off? Kind Regards --Andy

    Read the article

  • C# : What if a static method is called from multiple threads?

    - by Holli
    In my Application I have a static method that is called from multiple threads at the same time. Is there any danger of my data being mixed up? In my first attempt the method was not static and I was creating multiple instance of the class. In that case my data got mixed up somehow. I am not sure how this happens because it only happens sometimes. I am still debugging. But now the method is static on I have no problems so far. Maybe it's just luck. I don't know for sure.

    Read the article

  • Best practices for using Hg with Grails?

    - by leeand00
    What should I check in/not check in? Since many of the files are sometimes auto-generated I'm not entirely sure how to handle this using version control...does it have something to do with tags? For instance in ANT, I know not to check-in my target/bin directories...but Grails adds another level of confusion to this...since some of code is generated and some of it is not. (It may become clearer as I go...but it seems to be that there needs to be some way of being able to tell what was just generated and what was modified by a developer so that it needs to be placed in version control)

    Read the article

  • Is there a pattern that allows a constructor to be called only from a specific factory and from nowh

    - by willem
    We have a class, say LegacyUserSettingsService. LegacyUserSettingsService implements an interface, IUserSettingsService. You can get an instance of the IUserSettingsService by calling our ApplicationServicesFactory. The factory uses Spring.NET to construct the concrete LegacyUserSettingsService. The trouble is that new developers sometimes do their own thing and construct new instances of the LegacyUserSettingsService directly (instead of going via the factory). Is there a way to protect the constructor of the concrete class so it can only be called from the factory? A well-known pattern perhaps? Note that the concrete class resides in a different assembly (separate from the Factory's assembly, so the internal keyword is not a solution). The factory assembly references the other assembly that contains the concrete class. Any ideas?

    Read the article

  • python class attribute

    - by chnet
    Hi, i have a question about class attribute in python. class base : def __init__ (self): pass derived_val = 1 t1 = base() t2 = base () t2.derived_val +=1 t2.__class__.derived_val +=2 print t2.derived_val # its value is 2 print t2.__class__.derived_val # its value is 3 The results are different. I also use id() function to find t2.derived_val and t2.class.derived_val have different memory address. My problem is derived_val is class attribute. Why it is different in above example? Is it because the instance of class copy its own derived_val beside the class attribute?

    Read the article

  • Track unicode words from Twitter using Ruby and the Tweetstream API

    - by Régis B.
    I am trying to track a set of keywords from Twitter by using the Streaming API (can't post the link here because of spam limitations: google twitter streaming API). I am doing this inside Ruby, using the TweetStream gem: http://bit.ly/cODAWI The problem I have is that I want to track keywords that contain some unicode/UTF-8 characters. For instance: require 'rubygems' require 'tweetstream' TweetStream::Client.new("my_user_name", "my_password").track("é") do |s| puts s.text end (you can try it out, provided you installed the tweetstream and json gems) This piece of code does not print anything, while replacing "é" with "e" outputs a bunch of tweets continuously. I did not find any reliable documentation about Unicode in Ruby, so I have no idea where the problem comes from. Thanks for your help!

    Read the article

  • Type patterns in Haskell

    - by finnsson
    I'm trying to compile a simple example of generic classes / type patterns (see http://www.haskell.org/ghc/docs/latest/html/users_guide/generic-classes.html) in Haskell but it won't compile. Any ideas about what's wrong with the code would be helpful. According to the documentation there should be a module Generics with the data types Unit, :*:, and :+: but ghc (6.12.1) complaints about Not in scope: data constructor 'Unit' etc. It seems like there's a package instant-generics with the data types :*:, :+: and U but when I import that module (instead of Generics) I get the error Illegal type pattern in the generic bindings {myPrint _ = ""} The complete source code is import Generics.Instant class MyPrint a where myPrint :: a -> String myPrint {| U |} _ = "" myPrint {| a :*: b |} (x :*: y) = "" (show x) ++ ":*:" ++ (show y) myPrint {| a :+: b |} _ = "" data Foo = Foo String instance MyPrint a => MyPrint a main = myPrint $ Foo "hi" and I compile it using ghc --make Foo.hs -fglasgow-exts -XGenerics -XUndecidableInstances P.S. The module Generics export no data types, only the functions: canDoGenerics mkGenericRhs mkTyConGenericBinds validGenericInstanceType validGenericMethodType

    Read the article

  • Rails find_or_create by more than one attribute?

    - by tybro0103
    There is a handy dynamic attribute in active-record called find_or_create_by: Model.find_or_create_by_<attribute>(:<attribute> => "") But what if I need to find_or_create by more than one attribute? Say I have a model to handle a M:M relationship between Group and Member called GroupMember. I could have many instances where member_id = 4, but I don't ever want more than once instance where member_id = 4 and group_id = 7. I'm trying to figure out if it's possible to do something like this: GroupMember.find_or_create(:member_id => 4, :group_id => 7) I realize there may be better ways to handle this, but I like the convenience of the idea of find_or_create.

    Read the article

< Previous Page | 566 567 568 569 570 571 572 573 574 575 576 577  | Next Page >