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• Does ActiveRecord make Ruby on Rails code hard to test?

  - by Erik Öjebo

  I've spent most of my time in statically typed languages (primarily C#). I have some bad experiences with the Active Record pattern and unit testing, because of the static methods and the mix of entities and data access code. Since the Ruby community probably is the most test driven of the communities out there, and the Rails ActiveRecord seems popular, there must be some way of combining TDD and ActiveRecord based code in Ruby on Rails. I would guess that the problem goes away in dynamic languages, somehow, but I don't see how. So, what's the trick?

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• setDelegate:self, how does it work?

  - by fuzzygoat

  I have a query regarding how delegates work. My understanding was that delegates take responsibility for doing certain tasks on behalf of another object. locationManager = [[CLLocationManager alloc] init]; [locationManager setDelegate:self]; [locationManager setDistanceFilter:kCLDistanceFilterNone]; [locationManager setDesiredAccuracy:kCLLocationAccuracyBest]; [locationManager startUpdatingLocation]; Am I right in thinking that in the example code above that the instance of CLLocationManager is created on a new thread so that it can get on with trying to find the location information it needs. When it completes its task (or encounters an error) it calls-back using the appropriate methods located in self e.g. locationManager:didUpdateToLocation:fromLocation: Essentially locationManager sends messages to self (which conforms to the correct delegate protocol) when things happen cheers gary

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• addSublayer vs addSubView which is more efficient?

  - by soonio

  I have 5 UIImageViews for displaying 5 images. For my app, I need swap the order of them depending on some events. I achieve this by calling: [anImageView1 removeFromSuperview]; [self.view insertSubview:anImageView1 aboveSubview:anImageView2]; Recently, I've come across a different method for doing this using 1 UIView and 5 UIImageViews. Each layer of UIImageViews are added to this UIView by calling [aView.layer addSublayer:anImageView1.layer]; [aView.layer addSublayer:anImageView2.layer]; etc. and then in order to swap the order of things by calling [anImageView1.layer removeFromSuperLayer]; [aView.layer insertSublayer:anImageView1 above: anImageView2] Both methods work fine, but can someone please point out which method is better and why? I really can't seem to be able to find much on CALayer... Please help! Thank you so much!

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• double checked locking - objective c

  - by bandejapaisa

  I realised double checked locking is flawed in java due to the memory model, but that is usually associated with the singleton pattern and optimizing the creation of the singleton. What about under this case in objective-c: I have a boolean flag to determine if my application is streaming data or not. I have 3 methods, startStreaming, stopStreaming, streamingDataReceived and i protect them from multiple threads using: - (void) streamingDataReceived:(StreamingData *)streamingData { if (self.isStreaming) { @synchronized(self) { if (self.isStreaming) { - (void) stopStreaming { if (self.isStreaming) { @synchronized(self) { if (self.isStreaming) { - (void) startStreaming:(NSArray *)watchlistInstrumentData { if (!self.isStreaming) { @synchronized(self) { if (!self.isStreaming) { Is this double check uneccessary? Does the double check have similar problems in objective-c as in java? What are the alternatives to this pattern (anti-pattern). Thanks

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• Idiomatic ruby for temporary variables within a method

  - by Andrew Grimm

  Within a method, I am using i and j as temporary variables while calculating other variables. What is an idiomatic way of getting rid of i and j once they are no longer needed? Should I use blocks for this purpose? i = positions.first while nucleotide_at_position(i-1) == nucleotide_at_position(i) raise "Assumption violated" if i == 1 i -= 1 end first_nucleotide_position = i j = positions.last while nucleotide_at_position(j+1) == nucleotide_at_position(j) raise "Assumption violated" if j == sequence.length j += 1 end last_nucleotide_position = j Background: I'd like to get rid of i and j once they are no longer needed so that they aren't used by any other code in the method. Gives my code less opportunity to be wrong. I don't know the name of the concept - is it "encapsulation"? The closest concepts I can think of are (warning: links to TV Tropes - do not visit while working) Chekhov'sGun or YouHaveOutlivedYourUsefulness. Another alternative would be to put the code into their own methods, but that may detract from readability.

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• Retrieving Data from SQL Server within Excel 2007

  - by Russell Giddings

  I have the following requirements I have relational content stored in a SQL Server 2005 database. I want to retrieve this data, transform it and display it in an Excel 2007 document. I would like this to be pulled from within Excel at the click of a button. As far as I can tell I have the following options... Create a view in Sql Server and reference it within a pivot table using a data connection. Create an Excel workbook using VSTO and create a web service which the workbook pulls data from Create a web service and use JScript with XMLHTTP request objects I currently only have a little experience of any of these methods (I'm very familiar with SQL Server although not pivot tables, I've created many web services although I've never used VSTO and I've used javascript extensively, but never in the context of Excel manipulation). Would you recommend one of the above approaches or is there a better way to do this?

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• MVC: Model View Controller -- does the View call the Model?

  - by Gary Green

  I've been reading about MVC design for a while now and it seems officially the View calls objects and methods in the Model, builds and outputs a view. I think this is mainly wrong. The Controller should act and retrieve/update objects inside the Model, select an appropriate View and pass the information to it so it may display. Only crude and rudiementary PHP variables/simple if statements should appear inside the View. If the View gets the information it needs to display from the Model, surely there will be a lot of PHP inside the View -- completely violating the point of seperating presentation logic.

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• PHP class constant string variable spanning over multiple lines

  - by ebae

  I want to have a string variable for a PHP class, which would be available to all methods. However, this variable is quite long, so I want to separate it into multiple lines. For example, $variable = "line 1" . "line 2" . "line 3"; But above doesn't work. I tried EOD, but EOD is not allowed within class. And when I declare it outside the class, I can't access the variable from within the class. What is the best way?

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• What is the difference among NSString alloc:initWithCString versus stringWithUTF8String?

  - by mobibob

  I thought these two methods were (memory allocation-wise) equivalent, however, I was seeing "out of scope" and "NSCFString" in the debugger if I used what I thought was the convenient method (commented out below) and when I switched to the more explicit method my code stopped crashing! Notice that I am getting the string that is being stored in my container from sqlite3 query. p = (char*) sqlite3_column_text (queryStmt, 1); // GUID = (NSString*) [NSString stringWithUTF8String: (p!=NULL) ? p : ""]; GUID = [[NSString alloc] initWithCString:(p!=NULL) ? p : "" encoding:NSUTF8StringEncoding]; Also note, that if I looked at the values in the debugger and printed them with NSLog they looked correct, however, I don't think new memory was allocated and the value copied. Instead the memory pointer was stored - went out of scope - referenced later - crash!

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• How do I get the java.concurrency.CyclicBarrier to work as expected

  - by Ritesh M Nayak

  I am writing code that will spawn two thread and then wait for them to sync up using the CyclicBarrier class. Problem is that the cyclic barrier isn't working as expected and the main thread doesnt wait for the individual threads to finish. Here's how my code looks: class mythread extends Thread{ CyclicBarrier barrier; public mythread(CyclicBarrier barrier) { this.barrier = barrier; } public void run(){ barrier.await(); } } class MainClass{ public void spawnAndWait(){ CyclicBarrier barrier = new CyclicBarrier(2); mythread thread1 = new mythread(barrier).start(); mythread thread2 = new mythread(barrier).start(); System.out.println("Should wait till both threads finish executing before printing this"); } } Any idea what I am doing wrong? Or is there a better way to write these barrier synchronization methods? Please help.

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• Is generic Money<T_amount> a good idea?

  - by jdk

  I have a Money Type that allows math operations and is sensitive to exchange rates so it will reduce one currency to another if rate is available to calculate in a given currency, rounds by various methods. It has other features that are sensitive to money, but I need to ask if the basic data type used should be made generic in nature. I've realized that the basic data type to hold an amount may differ for financial situations, for example: retail money might be expressed as all cents using int or long where fractions of cents do not matter, decimal is commonly used for its fixed behaviour, sometimes double seems to be used for big finance and large values sometimes a special BigInteger or 3rd-party type is used. I want to know if it would be considered good form to turn Money into Money<T_amount> so it can be used in any one of the above chosen scenarios?

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• Generating Javascript from PHP?

  - by Aristotle

  Are there any libraries or tools specifically designed to help PHP programmers write Javascript? Essentially, converting the PHP logic into Javascript logic. For instance: $document = new Document($html); $myFoo = $document->getElementById("foo"); $myFoo->value = "Hello World"; Being converted into the following output: var myFoo = document.getElementById("foo"); myFoo.value = "Hello World"; Of course it would be excellent if more complicated solutions could be derived too, perhaps converting objects and internal methods into javascript-objects, etc.

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• Are All Dynamic Languages Typo-friendly?

  - by yar

  With Java on one side and Ruby/Groovy on the other, I know that in the second camp I'm free to make typos which will not get caught until run-time. Is this true of all dynamically-typed languages? Edit: I've been asked to elaborate on the type of typo. In Ruby and in Groovy, you can assign to a variable with an accidental name that is never read. You can call methods that don't exist (obviously your tests should catch this, it's been said). You can refer to classes that don't exist, etc. etc. Basically any valid syntax, even with typographical errors, is valid in both Ruby and Groovy.

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• Touch area changing on custom UIButton with image and title on landscape mode

  - by gkedmi

  hello all I'm trying to build a button that looks like the icons on the iphone , with an image and a title bellow.I'm working in landscape mode. I have a custom button on the IB with image and title and inside the code I use the methods : [aButton setTitleEdgeInsets:UIEdgeInsetsMake(60.0, -50.0, 0.0, 0.0)]; [aButton setImageEdgeInsets:UIEdgeInsetsMake(-10.0, 29.0, 0.0, 0.0)]; my problem is that the area that react to the touch events is very small and is on the top left of the button , another problem is that if I change my button size I have to calculate again manually the values for these 2 functions. Is there any easy way to do it?and if not how can I fix the touch area? thanks Gilad

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• Graphviz DOT arange Nodes in circles

  - by Ivo Wetzel

  OK here's my problem, I'm generating a graph of a python module, including all the files with their functions/methods/classes. I want to arrange it so, that nodes gather in circles around their parent nodes, currently everything is on one gargantuan horizontal row, which makes the thing 50k pixels wide and also let's the svg converter fail(only renders about the half of the graph). I went trough the docs(http://www.graphviz.org/doc/info/attrs.html) but couldn't find anything that seems to do the trick. So the question is: Is there a simple way to do this or do I have to layout the whole thing by myself? :/

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• Representing Objective C Protocols on UML class diagrams

  - by joec

  How should i correctly reference protocols on a UML class diagram? For example my ListViewController conforms to the UITableViewDataSource and UITableViewDelegate protocols... where do i put the cellForRowAtIndexPath or numberOfRowsInSection methods? ... in ListViewController where they are implemented or in something like this: <<Protocol>> UITableViewDataSource --------------------- --------------------- -numberOfRowsInSection If i did the latter what would be the association between the ListViewController class and the protocol box be? All i have to show is how i hook into Cocoa Touch some how. Thanks.

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• Graph databases and Php

  - by stagas

  I want to use a graph database using php. Can you point out some resources on where to get started? Is there any example code / tutorial out there? Or are there any other methods of storing data that relate to each other in totally random/abstract situations? Very abstract example of the relations needed: John relates to Mary, both relate to School, John is Tall, Mary is Short, John has Blue Eyes, Mary has Green Eyes, query I want is which people are related to 'Short people that have Green Eyes and go to School' - answer John It is possible in MySQL but it would require a fixed set of attributes/columns for each item and a complex non-flexible query, instead I need every attribute to be an item by itself and instead of 'belonging' to something, to be 'related' to something.

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• Convert/Cast base type to Derived type

  - by user102533

  I am extending the existing .NET framework class by deriving it. How do I convert an object of base type to derived type? public class Results { //Framework methods } public class MyResults : Results { //Nothing here } //I call the framework method public static MyResults GetResults() { Results results = new Results(); //Results results = new MyResults(); //tried this as well. results = CallFrameworkMethod(); return (MyResults)results; //Throws runtime exception } I understand that this happens as I am trying to cast a base type to a derived type and if derived type has additional properties, then the memory is not allocated. When I do add the additional properties, I don't care if they are initialized to null. How do I do this without doing a manual copy?

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• T-SQL How To: Compare and List Duplicate Entries in a Table

  - by Dan7el

  SQL Server 2000. Single table has a list of users that includes a unique user ID and a non-unique user name. I want to search the table and list out any users that share the same non-unique user name. For example, my table looks like this: ID User Name Name == ========= ==== 0 parker Peter Parker 1 parker Mary Jane Parker 2 heroman Joseph (Joey) Carter Jones 3 thehulk Bruce Banner What I want to do is do a SELECT and have the result set be: ID User Name Name == ========= ==== 0 parker Peter Parker 1 parker Mary Jane Parker from my table. I'm not a T-SQL guru. I can do the basic joins and such, but I'm thinking there must be an elegant way of doing this. Barring elegance, there must be ANY way of doing this. I appreciate any methods that you can help me with on this topic. Thanks! ---Dan---

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• DRY programming dilemma

  - by fayer

  the situation is like this: im creating a Logger class that can write to a file but the write_to_file() function is in a helper class as a static function. i could call that function but then the Log class would be dependent to the helper class. isn't dependency bad? but if i can let it use a helper function then what is the point of having helper functions? what should one prioritize here: using helper functions and have to include this helper class everywhere (but the other 99 methods wont be useful) or just copy and paste into the Log class (but then if i have done this 100 times and then make a change i have to change in 100 places). share your thoughts and experience!

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• jQuery - How to remove a DOM element BEFORE complete page load

  - by webfac

  Now this may seem like a silly question, but I need to know how to remove a DOM element BEFORE it is displayed to the user. In short, I am using a div that has a background image alerting the user to enable javascript before proceeding. If the user has javascript enabled I am using jQuery to remove the DOM element, in this case $(".check-js") which is the div housing the image. Using the conventional methods to unload DOM objects as follows does not work because it waits for the page load to complete, then removes the element, causing the image to flicker on and off each time the page loads: $(function(){ $(".check-js").css( {display:"none"} ) }) I simply want to remove the div if the user has js enabled, and he must never see this div. Any suggestions and I will be grateful, thanks.

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• What are the best measures to protect content from being crawled?

  - by Moak

  I've been crawling a lot of websites for content recently and am surprised how no site so far was able to put up much resistance. Ideally the site I'm working on should not be able to be harvested so easily. So I was wondering what are the best methods to stop bots from harvesting your web content. Obvious solutions: Robots.txt (yea right) IP blacklists What can be done to catch bot activity? What can be done to make data extraction difficult? What can be done to give them crap data? Just looking for ideas, no right/wrong answer

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• How does Entity Framework 4.0 determine which parameters are required for the factory method of an e

  - by Scott Davies

  Hi, I am working with Entity Framework 4.0 (VS 2010 Beta 2, NOT RC). I can model the EDM and produce the required database. When I ask VS to generate the code for the model, it generates the expected .designer.cs file. When I look at the factory methods for each entity that the designer has generated, I've noticed that it doesn't include all of the properties of the entity. Is it correct to say that the factory method only includes properties that cannot be null ? This appears to be the case, but I'm not entirely sure. Thanks, Scott

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• Why does a multilanguage solution not work?

  - by Lukas

  My solution has a C# application project C# User Controls project C++ Mathematics project One of the UserControls uses function from the Mathematics (C++ project). This UserControl is used in the application. Building and starting the application works just fine. When typing the IntelliSense suggests all the contained classes and methods. The UserControl appears correctly, but on clicking a button which calls the C++ function I get a BadImageFormatException (it pops out on the end of the automatically created Main function). The help suggests to use /fixed:no for linking, but that is already set up.

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• To call SelectMany dynamically in the way of System.Linq.Dynamic

  - by user341127

  In System.Linq.Dynamic, there are a few methods to form Select, Where and other Linq statements dynamically. But there is no for SelectMany. The method for Select is as the following: public static IQueryable Select(this IQueryable source, string selector, params object[] values) { if (source == null) throw new ArgumentNullException("source"); if (selector == null) throw new ArgumentNullException("selector"); LambdaExpression lambda = DynamicExpression.ParseLambda(source.ElementType, null, selector, values); IQueryable result = source.Provider.CreateQuery( Expression.Call( typeof(Queryable), "Select", new Type[] { source.ElementType, lambda.Body.Type }, source.Expression, Expression.Quote(lambda))); return result; } I tried to modify the above code, after hours working, I couldn't find a way out. Any suggestions are welcome. Ying

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