Search Results

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

Page 155/797 | < Previous Page | 151 152 153 154 155 156 157 158 159 160 161 162  | Next Page >

• Grails design for domain class initialization from static data

  - by Allison Eer

  I have some data, stateNames, to instantiate an instance of the object Country. Right now, I will only have one Country but stateNames for each country should be different. What is the best way to instantiate the instance of Country with my data? I am new to grails and would appreciate any "best practices" or common designs. One solution I can think of is to use BootStrap to save the unitedStates instance of Country to the database. What are the cons of this approach? Another solution would be to save the data in a file (in xml?) under web-app folder. If I did this approach, should the unitedStates instance of Country be instantiated by a controller?

  Read the article

• Howto check if a object is connected to another in hibernate

  - by codevourer

  Imagine two domain object classes, A and B. A has a bidirectional one-to-many relationship to B. A is related to thousands of B. The relations must be unique, it's not possible to have a duplicate. To check if an instance of B is already connected to a given instance of A, we could perform an easy INNER JOIN but this will only ensure the already persisted relations. What about the current transient relations? class A { @OneToMany private List<B> listOfB; } If we access the listOfB and perform a check of contains() this will fetch all the connected instances of B lazy from the datasource. I only want to validate them by their primary-key. Is there an easy solution where I can do things like "Does this instance of A is connected with this instance of B?" Without loading all these data into memory and perform a based on collections?

  Read the article

• Rails - Paperclip, getting width and height of image in model

  - by Corey Tenold

  Trying to get the width and height of the uploaded image while still in the model on the initial save. Any way to do this? Here's the snippet of code I've been testing with from my model. Of course it fails on "instance.photo_width". has_attached_file :photo, :styles => { :original => "634x471>", :thumb => Proc.new { |instance| ratio = instance.photo_width/instance.photo_height min_width = 142 min_height = 119 if ratio > 1 final_height = min_height final_width = final_height * ratio else final_width = min_width final_height = final_width * ratio end "#{final_width}x#{final_height}" } }, :storage => :s3, :s3_credentials => "#{RAILS_ROOT}/config/s3.yml", :path => ":attachment/:id/:style.:extension", :bucket => 'foo_bucket' So I'm basically trying to do this to get a custom thumbnail width and height based on the initial image dimensions. Any ideas?

  Read the article

• SQLiteOpenHelper getWritableDatabse() fails with no Exception

  - by Michal K

  I have a very strange problem. It only shows from time to time, on several devices. Can't seem to reproduce it when I want, but had it so many times, that I think I know where I get it. So I have a Loader which connects to sqlite through a singleton SQLiteOpenHelper: try{ Log.i(TAG, "Get details offline / db helper: "+DatabaseHelper.getInstance(getContext())); SQLiteDatabase db=DatabaseHelper.getInstance(this.getContext()).getWritableDatabase(); Log.i(TAG, "Get details offline / db: "+db); //doing some work on the db //... } catch(SQLiteException e){ e.printStackTrace(); return null; } catch(Exception e){ e.printStackTrace(); return null; //trying everything to grab some exception or whatever } My SQLIteOpenHelper looks something like this: public class DatabaseHelper extends SQLiteOpenHelper { private static DatabaseHelper mInstance = null; private static Context mCxt; public static DatabaseHelper getInstance(Context cxt) { //using app context ass suggested by CommonsWare Log.i("DBHELPER1", "cxt"+mCxt+" / instance: "+mInstance); if (mInstance == null) { mInstance = new DatabaseHelper(cxt.getApplicationContext()); } Log.i("DBHELPER2", "cxt"+mCxt+" / instance: "+mInstance); mCxt = cxt; return mInstance; } //private constructor private DatabaseHelper(Context context) { super(context, DATABASE_NAME, null, DATABASE_VERSION); this.mCxt = context; } @Override public void onCreate(SQLiteDatabase db) { //some tables created here } @Override public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) { //upgrade code here } It really works great in most cases. But from time to time I get a log similar to this: 06-10 23:49:59.621: I/DBHELPER1(26499): cxtcom.bananout.Bananout@407152c8 / instance: com.bananout.helpers.DatabaseHelper@40827560 06-10 23:49:59.631: I/DBHELPER2(26499): cxtcom.bananout.Bananout@407152c8 / instance: com.bananout.helpers.DatabaseHelper@40827560 06-10 23:49:59.631: I/DetailsLoader(26499): Get event details offline / db helper: com.bananout.helpers.DatabaseHelper@40827560 06-10 23:49:59.631: I/DBHELPER1(26499): cxtcom.bananout.Bananout@407152c8 / instance: com.bananout.helpers.DatabaseHelper@40827560 06-10 23:49:59.651: I/DBHELPER2(26499): cxtcom.bananout.Bananout@407152c8 / instance: com.bananout.helpers.DatabaseHelper@40827560 This line Log.i(TAG, "Get details offline / db: "+db); never gets called! No Exceptions, silence. Plus, the thread with the Loader is not running anymore. So nothing past this line SQLiteDatabase db=DatabaseHelper.getInstance(this.getContext()).getWritableDatabase(); gets executed. What can possibly go wrong on this line?

  Read the article

• Threads slowing down application and not working properly

  - by Belgin

  I'm making a software renderer which does per-polygon rasterization using a floating point digital differential analyzer algorithm. My idea was to create two threads for rasterization and have them work like so: one thread draws each even scanline in a polygon and the other thread draws each odd scanline, and they both start working at the same time, but the main application waits for both of them to finish and then pauses them before continuing with other computations. As this is the first time I'm making a threaded application, I'm not sure if the following method for thread synchronization is correct: First of all, I use two global variables to control the two threads, if a global variable is set to 1, that means the thread can start working, otherwise it must not work. This is checked by the thread running an infinite loop and if it detects that the global variable has changed its value, it does its job and then sets the variable back to 0 again. The main program also uses an empty while to check when both variables become 0 after setting them to 1. Second, each thread is assigned a global structure which contains information about the triangle that is about to be rasterized. The structures are filled in by the main program before setting the global variables to 1. My dilemma is that, while this process works under some conditions, it slows down the program considerably, and also it fails to run properly when compiled for Release in Visual Studio, or when compiled with any sort of -O optimization with gcc (i.e. nothing on screen, even SEGFAULTs). The program isn't much faster by default without threads, which you can see for yourself by commenting out the #define THREADS directive, but if I apply optimizations, it becomes much faster (especially with gcc -Ofast -march=native). N.B. It might not compile with gcc because of fscanf_s calls, but you can replace those with the usual fscanf, if you wish to use gcc. Because there is a lot of code, too much for here or pastebin, I created a git repository where you can view it. My questions are: Why does adding these two threads slow down my application? Why doesn't it work when compiling for Release or with optimizations? Can I speed up the application with threads? If so, how? Thanks in advance.

  Read the article

• Some Interesting T-SQL Scripts Regarding to Transactions Related to Identity Fields and Table Variab

  This article introduces some interesting T-SQL scripts regarding to transactions related to the identity fields and table variables

  Read the article

• Who needs singletons?

  - by sexyprout

  Imagine you access your MySQL database via PDO. You got some functions, and in these functions, you need to access the database. The first thing I thought of is global, like: $db = new PDO('mysql:host=127.0.0.1;dbname=toto', 'root', 'pwd'); function some_function() { global $db; $db->query('...'); } But it's considered as a bad practice. So, after a little search, I ended up with the Singleton pattern, which "applies to situations in which there needs to be a single instance of a class." According to the example of the manual, we should do this: class Database { private static $instance, $db; private function __construct(){} static function singleton() { if(!isset(self::$instance)) self::$instance = new __CLASS__; return self:$instance; } function get() { if(!isset(self::$db)) self::$db = new PDO('mysql:host=127.0.0.1;dbname=toto', 'user', 'pwd') return self::$db; } } function some_function() { $db = Database::singleton(); $db->get()->query('...'); } some_function(); But I just can't understand why you need that big class when you can do it merely with: class Database { private static $db; private function __construct(){} static function get() { if(!isset(self::$rand)) self::$db = new PDO('mysql:host=127.0.0.1;dbname=toto', 'user', 'pwd'); return self::$db; } } function some_function() { Database::get()->query('...'); } some_function(); This last one works perfectly and I don't need to worry about $db anymore. But maybe I'm forgetting something. So, who's wrong, who's right?

  Read the article

• 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?

  Read the article

• Add console.profile statements to JavaScript/jQuery code on the fly.

  - by novogeek

  Hi folks, We have a thick client app using jQuery heavily and want to profile the performance of the code using firebug's console.profile API. The problem is, I don't want to change the code to write the profile statements. Take this example: var search=function(){ this.init=function(){ console.log('init'); } this.ajax=function(){ console.log('ajax'); //make ajax call using $.ajax and do some DOM manipulations here.. } this.cache=function(){ console.log('cache'); } } var instance=new search(); instance.ajax(); I want to profile my instance.ajax method, but I dont want to add profile statements in the code, as that makes it difficult to maintain the code. I'm trying to override the methods using closures, like this: http://www.novogeek.com/post/2010/02/27/Overriding-jQueryJavaScript-functions-using-closures.aspx but am not very sure how I can achieve. Any pointers on this? I think this would help many big projects to profile the code easily without a big change in code. Here is the idea. Just run the below code in firebug console, to know what I'm trying to achieve. var search=function(){ this.init=function(){ console.log('init'); } this.ajax=function(){ console.log('ajax'); //make ajax call using $.ajax and do some DOM manipulations here.. } this.cache=function(){ console.log('cache'); } } var instance=new search(); $.each(instance, function(functionName, functionBody){ (function(){ var dup=functionBody functionBody=function(){ console.log('modifying the old function: ',functionName); console.profile(functionName); dup.apply(this,arguments); console.profileEnd(functionName); } })(); console.log(functionName, '::', functionBody()); }); Now what I need is, if i say instance.ajax(), I want the new ajax() method to be called, along with the console.profile statements. Hope I'm clear with the requirement. Please improvise the above code. Regards, Krishna, http://www.novogeek.com

  Read the article

• Override generic methods in c#

  - by Pascal

  I thought I can not override generic methods of a derived class. http://my.safaribooksonline.com/book/programming/csharp/9780071741163/generics/ch18lev1sec13 The code in this link runs fine. The overriden method is called although the instance type of the base class is used and not the instance of the derived type. Now I am confused because a former question of mine Type parameter declaration must be identifier not a type is about calling the overriding generic method with the instance of base type which did NOT work!

  Read the article

• How to enable a Web portal-based enterprise platform on different domains and hosts without customization [on hold]

  - by S.Jalali

  At Coscend, a cloud and communications software product company, we have built a Web portal-based collaboration platform that we like to host on five different Windows- and Linux-based servers in different hosting environments that run Web servers. Each of these Windows and Linux servers has a different host name and domain name (and IP address). Our team would appreciate your guidance on: (1) Is there a way to implement this Web portal-based platform on these Linux and Windows servers without customizing the host name, domain name and IP address for each individual instance? (2) Is there a way to create some variables using JavaScript for host name and domain name and call them from the different implementations? If a reference to the host/domain names occurs on hundreds of our pages, the variables or objects would replace that. (3) This is part of making these JavaScript modules portable and re-usable for different environments and instances. The portal is written in JavaScript that is embedded in HTML5 and padded with CSS3. Other technologies include Flash, Flex, PostgreSQL and MySQL.

  Read the article

• when to make a method static

  - by Don

  Hi, I'd like to know how people decide whether to define a method as static. I'm aware that a method can only be defined as static if it doesn't require access to instance fields. So lets say we have a method that does not access instance fields, do you always define such a method as static, or only if you need to call it statically (without a reference to an instance). Perhaps another way of asking the same question, is whether you use static or non-static as the default? Thanks, Don

  Read the article

• Thread-safe use of a singleton's members

  - by Anthony Mastrean

  I have a C# singleton class that multiple classes use. Is access through Instance to the Toggle() method thread-safe? If yes, by what assumptions, rules, etc. If no, why and how can I fix it? public class MyClass { private static readonly MyClass instance = new MyClass(); public static MyClass Instance { get { return instance; } } private int value = 0; public int Toggle() { if(value == 0) { value = 1; } else if(value == 1) { value = 0; } return value; } }

  Read the article

• Where can I get a definition of how the code is laid out in VB.NET 2010?

  - by ByteWorker

  I am just starting out learning Visual Basic 2010. I have books and videos. The books all seem to be written for people who have some programming experience, even the books that say they are for beginners. The videos were great until they started talking about variables. I got the basics of them but they started into complicated variables and I don’t see the need for them right away. Where can I go to see code for fairly intricate applications written out, with an over lay of definitions of which part of the code is a method as opposed to a class and so on? Also, I am working at a company that does not use SQL. So I need to use Access 2007 for all of my tables. Is there much of a difference to the coding?

  Read the article

• Is there any mercurial hosting actually *on* Amazon EC2?

  - by Neil Trodden

  I need to be able to update my ec2 instance from a label in mercurial when it resets so my application is always set at the right revision. It'd be great to be able to push my changes to a mercurial host and have my instances automatically update across the ec2 network when they are reset! I really don't want to host mercurial on the same instance (or even a dedicated instance)

  Read the article

• using static methods and classes

  - by vedant1811

  I know that static methods/variables are associated with the class and not the objects of the class and are useful in situations when we need to keep count of, say the number of objects of the class that were created. Non-static members on the other hand may need to work on the specific object (i.e. to use the variables initialized by the constructor) My question what should we do when we need neither of the functionalities? Say I just need a utility function that accepts value(s) and returns a value besed solely on the values passed. I want to know whether such methods should be static or not. How is programming efficiency affected and which is a better coding practice/convention and why. PS: I don't want to spark off a debate, I just want a subjective answer and/or references.

  Read the article

• How can this Ambient Context become null?

  - by Mark Seemann

  Can anyone help me explain how TimeProvider.Current can become null in the following class? public abstract class TimeProvider { private static TimeProvider current = DefaultTimeProvider.Instance; public static TimeProvider Current { get { return TimeProvider.current; } set { if (value == null) { throw new ArgumentNullException("value"); } TimeProvider.current = value; } } public abstract DateTime UtcNow { get; } public static void ResetToDefault() { TimeProvider.current = DefaultTimeProvider.Instance; } } Observations All unit tests that directly reference TimeProvider also invokes ResetToDefault() in their Fixture Teardown. There is no multithreaded code involved. Once in a while, one of the unit tests fail because TimeProvider.Current is null (NullReferenceException is thrown). This only happens when I run the entire suite, but not when I just run a single unit test, suggesting to me that there is some subtle test interdependence going on. It happens approximately once every five or six test runs. When a failure occurs, it seems to be occuring in the first executed tests that involves TimeProvider.Current. More than one test can fail, but only one fails in a given test run. FWIW, here's the DefaultTimeProvider class as well: public class DefaultTimeProvider : TimeProvider { private readonly static DefaultTimeProvider instance = new DefaultTimeProvider(); private DefaultTimeProvider() { } public override DateTime UtcNow { get { return DateTime.UtcNow; } } public static DefaultTimeProvider Instance { get { return DefaultTimeProvider.instance; } } } I suspect that there's some subtle interplay going on with static initialization where the runtime is actually allowed to access TimeProvider.Current before all static initialization has finished, but I can't quite put my finger on it. Any help is appreciated.

  Read the article

• Python - Access a class from a list using a key

  - by Fake Name

  Is there any way to make a list of classes behave like a set in python? Basically, I'm working on a piece of software that does some involved string comparison, and I have a custom class for handling the strings. Therefore, there is an instance of the class for each string. As a result, I have a large list containing all these classes. I would like to be able to access them like list[key], where in this case, the key is a string the class is based off of. It seems to me that I sould be able to do this somewhat easily, by adding something like __cmp__ to the class, but either I'm being obtuse (likely), or Im missing someting in the docs. Basically, I want to be able to do something like this (Python prompt example): >>class a: ... def __init__(self, x): ... self.var = x ... >>> from test import a >>> cl = set([a("Hello"), a("World"), a("Pie")]) >>> print cl set([<test.a instance at 0x00C866C0>, <test.a instance at 0x00C866E8>, <test.a instance at 0x00C86710>]) >>> cl["World"] <test.a instance at 0x00C866E8> Thanks!

  Read the article

• How can I improve these online java programming puzzles I wrote for my (middle/high school) students?

  - by Arcymag

  I'm teaching some middle and high school students programming right now, and I found that some of them really liked online programming puzzles. So I created http://www.kapparate.com/coder/ , and right now there's 4 categories of puzzles. All the puzzles are set up right now so that variables are pre-initialized, and the user plugs in some code in the middle. For example, the problem might say these are pre-initialized: int x = ????; int y = ????; int z; and then the program might ask the student to write the final line of code: z = x + y;. Now I know I could go a long way in improving the usability of this site (like having an area that lists the pre-defined variables), but I was wondering if this concept seems sound. I know some sites have kids fill in functions, but not all of my students know what functions are yet, and I'm trying to introduce online programming puzzles before that.

  Read the article

• How to get or Kill all instances from certain class?

  - by Ehab Sutan

  How can I get all instances from a certain class or kill all instances of certain class? For Example, I've a Class MyClass which I intantiate three times as m1, m2 and m3. Is there a way to get or kill all these instances? more clarification : when I've a "settings form" class. When the user click Settings button the application makes instance from this class. When he clicks the same button again it makes new instance. I want it show the 1st instance only and not making new instance

  Read the article

• Typeclass instances for unnamed types in Scala

  - by ncreep

  How would one encode the following constraint in Scala (pseudocode)? def foo(x: T forSome { type T has a Numeric[T] instance in scope }) = { val n= implicitly[...] // obtain the Numeric instance for x n.negate(x) // and use it with x } In words: I need a type class instance for my input argument, but I don't care about the argument's type, I just need to obtain the instance and use it on my argument. It doesn't have to be an existential type, but I need to avoid type parameters in the def's signature. Thanks.

  Read the article

• Storing and reading file paths from _TCHAR *argv[]

  - by ArsenArsen

  How to convert from _TCHAR* to "" and to keep all : and /? I tried: int _tmain(int argc, _TCHAR* argv[]) { if(!argv[1]){ std::cout<<"No Variables.\r\n"; system("PAUSE"); return 0; std::exit; } std::cout<<"Path: "<<argv[1]<<"\r\n"; system("PAUSE"); return 0; } But, output is either "No variables." or "Path: C" (when I changed _TCHAR to const char and char) or either "Path: 00038706"

  Read the article

• PHP troubleshooting unexpected T_PUBLIC error

  - by jasondavis

  PHP is driving me insane right now, please help me, I must be missing something. In this VERY BASIC example below I get this error... Parse error:syntax error, unexpected T_PUBLIC in C:\filename here on line 12 On this line.... public static function getInstance(){ The code... <?PHP class Session{ private static $instance; function __construct() { { session_start(); echo 'Session object created<BR><BR>'; } public static function getInstance(){ if (!self::$instance) { self::$instance = new Session(); } return self::$instance; } }

  Read the article

• Can someone please help me in setting up Zend framework? [closed]

  - by Rolen Koh

  I need help in setting up Zend framework on my PC. I am using XAMPP on Windows 7. I read tutorials and did what they suggested but don't know why it is not running. I need stepwise help. I have downloaded Zend version 1.11.13 and extracted the contents in a C drive folder. I have also set up environment variables and also made proper changes in php.ini file. But still not working. May be I am missing something or doing something incorrectly. So could you please give me step by step details of everything from download to setting environment variables and etc? It'll be very helpful. Thanks a lot in advance.

  Read the article

• How to efficiently get all instances from deeper level in Cocoa model?

  - by Johan Kool

  In my Cocoa Mac app I have an instance A which contains an unordered set of instances B which in turn has an ordered set of instances C. An instance of C can only be in one instance B and B only in one A.   I would like to have an unordered set of all instances C available on instance A. I could enumerate over all instances B each time, but that seems expensive for something I need to do often. However, I am a bit worried that keeping track of instances C in A could become cumbersome and be the cause of  inconsistencies, for example if an instance C gets removed from B but not from A.  Solution 1 Use a NSMutableSet in A and add or remove C instances whenever I do the same operation in B.  Solution 2 Use a weak referenced NSHashTable in A. When deleting a C from B, it should disappear for A as well.  Solution 3 Use key value observing in A to keep track of changes in B, and update a NSMutableSet in A accordingly.  Solution 4 Simply iterate over all instances B to create the set whenever I need it.   Which way is best? Are there any other approaches that I missed?  NB I don't and won't use CoreData for this app.

  Read the article

< Previous Page | 151 152 153 154 155 156 157 158 159 160 161 162  | Next Page >