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• How do I reliably get the size of my iPhone view taking rotations into consideration?

  - by Sebastian Celis

  My application uses a UITabBarController, multiple UINavigationControllers, and supports autorotation. In order to properly layout the subviews within each UIViewController's main view, I really need to know the size available to the UIViewContoller. I need this size to take the UINavigationBar, the UITabBar, and the status bar all into account, and thus only return the size available to the content view. I thought for sure I could use the following from within the UIViewController's code: CGRect viewControllerBounds = [[self view] bounds]; However, there are a couple of issues with this approach: The first time the view is loaded, viewControllerBounds reports the view as being 320 pixels wide by 460 pixels tall. This is wrong. With a status bar and a navigation bar showing, the height should only be 416 pixels. However, if I rotate the simulator to landscape and then rotate back, the height of viewControllerBounds changes to 416. If I rotate the first view in the navigation controller to landscape mode and then push another view controller onto the stack, viewControllerBounds for the new view reports a width of 300 pixels and a height of 480 pixels. So the view's bounds didn't even take the rotation into account. Is there a better way to do this? I really don't want to have to start hardcoding the widths and heights of all the various UI elements the iPhone OS provides. I have tried setting the autoresizing mask of the UIViewController's view, but that doesn't seem to change anything. The views definitely seem to be displaying properly. When I set a background color that view looks like it takes up all of the space available to it. Any pointers would be greatly appreciated.

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• Need simple advice for graph solving problem

  - by sap

  Hi there, a collegue of mine proposed to me an exercise from an online judge website, which is basically a graph solving problem of an evacuation plan on a small town. i dont need the answer (nor do i want it) i just need an advice on which is the best approach to solving it since im kinda new to these kind of problems. the problem consists of town buildings with workers and fallout shelters in case of a nuclear attack. i have to build an algorithm that will assign the workers of each building to one or more fallout shelters but in a way that some shelters wont became too overcrowded while others remain almost empty (else i would just make the workers go to the nearest one). the problem is this: http://acm.timus.ru/problem.aspx?space=1&num=1237 in case its offline heres the google cached version of it: http://webcache.googleusercontent.com/search?q=cache:t2EPCzezs7AJ:acm.timus.ru/problem.aspx%3Fspace%3D1%26num%3D1237+vladimir+kotov+evacuation+problem&cd=1&hl=pt-PT&ct=clnk&gl=pt what i've done so far is for each building get the nearest shelter and move the number of workers from that build equal to the shelter capacity. then move to the next building. but sometimes the number of workers is greater than the shelter capacity, in that case after i iterate through every building, ill just iterate then again apllying the same algorithm until every building has 0 workers in it, problem is this is hardly the best way to solve it. any tip is welcome, please dont feel like im asking for the answer, i just want an advice in the right direction of solving it. thanks in advance.

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• Re-use of database object in sub-sonic

  - by cantabilesoftware

  Yet another newbie SubSonic/ActiveRecord question. Suppose I want to insert a couple of records, currently I'm doing this: using (var scope = new System.Transactions.TransactionScope()) { // Insert company company c = new company(); c.name = "ACME"; c.Save(); // Insert some options company_option o = new company_option(); o.name = "ColorScheme"; o.value = "Red"; o.company_id = c.company_id; o.Save(); o = new company_option(); o.name = "PreferredMode"; o.value = "Fast"; o.company_id = c.company_id; o.Save(); scope.Complete(); } Stepping through this code however, each of the company/company_option constructors go off and create a new myappDB object which just seems wasteful. Is this the recommended approach or should I be trying to re-use a single DB object - and if so, what's the easiest way to do this?

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• Have I taken a wrong path in programming by being excessively worried about code elegance and style?

  - by Ygam

  I am in a major stump right now. I am a BSIT graduate, but I only started actual programming less than a year ago. I observed that I have the following attitude in programming: I tend to be more of a purist, scorning unelegant approaches to solving problems using code I tend to look at anything in a large scale, planning everything before I start coding, either in simple flowcharts or complex UML charts I have a really strong impulse on refactoring my code, even if I miss deadlines or prolong development times I am obsessed with good directory structures, file naming conventions, class, method, and variable naming conventions I tend to always want to study something new, even, as I said, at the cost of missing deadlines I tend to see software development as something to engineer, to architect; that is, seeing how things relate to each other and how blocks of code can interact (I am a huge fan of loose coupling) i.e the OOP thinking I tend to combine OOP and procedural coding whenever I see fit I want my code to execute fast (thus the elegant approaches and refactoring) This bothers me because I see my colleagues doing much better the other way around (aside from the fact that they started programming since our first year in college). By the other way around I mean, they fire up coding, gets the job done much faster because they don't have to really look at how clean their codes are or how elegant their algorithms are, they don't bother with OOP however big their projects are, they mostly use web APIs, piece them together and voila! Working code! CLients are happy, they get paid fast, at the expense of a really unmaintainable or hard-to-read code that lacks structure and conventions, or slow executions of certain actions (which the common reasoning against would be that internet connections are much faster these days, hardware is more powerful). The excuse I often receive is clients don't care about how you write the code, but they do care about how long you deliver it. If it works then all is good. Now, did my "purist" approach to programming may have been the wrong way to start programming? Should I just dump these purist concepts and just code the hell up because I have seen it: clients don't really care how beautifully coded it is?

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• Java: Implement own message queue (threadsafe)

  - by derMax

  The task is to implement my own messagequeue that is thread safe. My approach: public class MessageQueue { /** * Number of strings (messages) that can be stored in the queue. */ private int capacity; /** * The queue itself, all incoming messages are stored in here. */ private Vector<String> queue = new Vector<String>(capacity); /** * Constructor, initializes the queue. * * @param capacity The number of messages allowed in the queue. */ public MessageQueue(int capacity) { this.capacity = capacity; } /** * Adds a new message to the queue. If the queue is full, it waits until a message is released. * * @param message */ public synchronized void send(String message) { //TODO check } /** * Receives a new message and removes it from the queue. * * @return */ public synchronized String receive() { //TODO check return "0"; } } If the queue is empty and I call remove(), I want to call wait() so that another thread can use the send() method. Respectively, I have to call notifyAll() after every iteration. Question: Is that possible? I mean does it work that when I say wait() in one method of an object, that I can then execute another method of the same object? And another question: Does that seem to be clever?

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• How to implement custom JSF component for drawing chart?

  - by Roman

  I want to create a component which can be used like: <mc:chart data="#{bean.data}" width="200" height="300" /> where #{bean.data} returns a collection of some objects or chart model object or something else what can be represented as a chart (to put it simple, let's assume it returns a collection of integers). I want this component to generate html like this: <img src="someimg123.png" width="200" height="300"/> The problem is that I have some method which can receive data and return image, like: public RenderedImage getChartImage (Collection<Integer> data) { ... } and I also have a component for drawing dynamic image: <o:dynamicImage width="200" height="300" data="#{bean.readyChartImage}/> This component generates html just as I need but it's parameter is array of bytes or RenderedImage i.e. it needs method in bean like this: public RenderedImage getReadyChartImage () { ... } So, one approach is to use propertyChangedListener on submit to set data (Collection<Integer>) for drawing chart and then use <o:dynamicImage /> component. But I'd like to create my own component which receives data and draws chart. I'm using facelets but it's not so important indeed. Any ideas how to create the desired component? P.S. One solution I was thinking about is not to use <o:dynamicImage/> and use some servlet to stream image. But I don't know how to implement that correctly and how to tie jsf component with servlet and how to save already built chart images (generating new same image for each request can cause performance problems imho) and so on..

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• Java library class to handle scheduled execution of "callbacks"?

  - by Hanno Fietz

  My program has a component - dubbed the Scheduler - that lets other components register points in time at which they want to be called back. This should work much like the Unix cron service, i. e. you tell the Scheduler "notify me at ten minutes past every full hour". I realize there are no real callbacks in Java. Here's my approach, is there a library which already does this stuff? Feel free to suggest improvements, too. Register call to Scheduler passes: a time specification containing hour, minute, second, year month, dom, dow, where each item may be unspecified, meaning "execute it every hour / minute etc." (just like crontabs) an object containing data that will tell the calling object what to do when it is notified by the Scheduler. The Scheduler does not process this data, just stores it and passes it back upon notification. a reference to the calling object Upon startup, or after a new registration request, the Scheduler starts with a Calendar object of the current system time and checks if there are any entries in the database that match this point in time. If there are, they are executed and the process starts over. If there aren't, the time in the Calendar object is incremented by one second and the entreis are rechecked. This repeats until there is one entry or more that match(es). (Discrete Event Simulation) The Scheduler will then remember that timestamp, sleep and wake every second to check if it is already there. If it happens to wake up and the time has already passed, it starts over, likewise if the time has come and the jobs have been executed. Edit: Thanks for pointing me to Quartz. I'm looking for something much smaller, however.

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• How to intercept, parse and compile?

  - by epitka

  This is a problem I've been struggling to solve for a while. I need a way to either replace code in the method with a parsed code from the template at compile time (PostSharp comes to mind) or to create a dynamic proxy (Linfu or Castle). So given a source code like this [Template] private string GetSomething() { var template = [%=Customer.Name%] } I need it to be compiled into this private string GetSomething() { MemoryStream mStream = new MemoryStream(); StreamWriter writer = new StreamWriter(mStream,System.Text.Encoding.UTF8); writer.Write(@"" ); writer.Write(Customer.Name); StreamReader sr = new StreamReader(mStream); writer.Flush(); mStream.Position = 0; return sr.ReadToEnd(); } It is not important what technology is used. I tried with PostSharp's ImplementMethodAspect but got nowhere (due to lack of experience with it). I also looked into Linfu framework. Can somebody suggest some other approach or way to do this, I would really appreciate. My whole project depends on this.

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• Symfony dynamic forms

  - by Asier

  Hi there, I started with a form, which is made by hand because of it's complexity (it's a javascript modified form, with sortable parts, etc). The problem is that now I need to do the validation, and it's a total mess to do it from scratch in the action using the sfValidator* classes. So, I am thinking to do it using sfForm so that my form validation and error handling can be done more easier and so I can reuse this form for the Edit and Create pages. The form is something like this: <form> <input name="form[year]"/> <textarea name="form[description]"></textarea> <div class="sortable"> <div class="item"> <input name="form[items][0][name]"/> <input name="form[items][0][age]"/> </div> <div class="item"> <input name="form[items][1][name]"/> <input name="form[items][1][age]"/> </div> </div> </form> The thing is that the sortable part of the form can be expanded from 2 to N elements on the client side. So that it has variable items quantity which can be reordered. How can I approach this problem? Any ideas are welcome, thank you. :)

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• PHP import functions

  - by ninuhadida

  Hi, I'm trying to find the best pragmatic approach to import functions on the fly... let me explain. Say I have a directory called functions which has these files: array_select.func.php stat_mediam.func.php stat_mean.func.php ..... I would like to: load each individual file (which has a function defined inside) and use it just like an internal php function.. such as array_pop(), array_shift(), etc. Once I stumbled on a tutorial (which I can't find again now) that compiled user defined functions as part of a PHP installation.. Although that's not a very good solution because on shared/reseller hosting you can't recompile the PHP installation. I don't want to have conflicts with future versions of PHP / other extensions, i.e. if a function named X by me, is suddenly part of the internal php functions (even though it might not have the same functionality per se) I don't want PHP to throw a fatal error because of this and fail miserably. So the best method that I can think of is to check if a function is defined, using function_exists(), if so throw a notice so that it's easy to track in the log files, otherwise define the function. However that will probably translate to having a lot of include/require statement in other files where I need such a function, which I don't really like. Or possibly, read the directory and loop over each *.func.php file and include_once. Though I find this a bit ugly. The question is, have you ever stumbled upon some source code which handled such a case? How was it implemented? Did you ever do something similar? I need as much ideas as possible! :)

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• Changing the parameters of a Javascript function using GreaseMonkey

  - by Dave

  There are a lot of questions here about Greasemonkey, but I didn't see anything directly related to my question. I'm on a website that uses a text editor control, and it's really annoying that they don't allow horizontal resizing (only vertical). So if you are using a cheapo projector that only supports 1024x768, the text runs off of the screen and there's nothing you can do about it. I looked at the page source, and found the section of code that I want Greasemonkey to modify: <script type="text/javascript"> // TinyMCE instance type: CD_TinyMCE tinyMCE.init({ convert_urls : "", mode : "specific_textareas", editor_selector : "rte", theme : "advanced", theme_advanced_toolbar_location : "top", theme_advanced_toolbar_align : "left", theme_advanced_statusbar_location : "bottom", theme_advanced_resizing : true, **theme_advanced_resize_horizontal : false**, ... I just want to change the boldfaced value to true. I tried to approach this the brute force way and replace the text this way: function allowHorizontalResize() { var search_string = "theme_advanced_resize_horizontal : false"; var replace_string = "theme_advanced_resize_horizontal : true"; var doc_text = document.body.innerHTML; document.body.innerHTML = doc_text.replace( search_string, replace_string); } ...but it doesn't work. However, I know the basic search and replace part works because I can use this script to replace text within the editor -- I just can't change the javascript code that initializes the text editor. Can someone explain what I'm doing wrong? Is this even possible?

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• Sencha touch 2/ app workflow with navigation view

  - by eplatonov

  I am trying to understand how can I implement the same functionality which provides navigation view in sencha touch 2, but .... Each item of the 'Ext.NavigationView' component should have it's own unique set of 'navigationBar' elements. I mean set of buttons, for example. I know that I can do something like this: this.getMain().getNavigationBar().rightBox.removeAll(); this.getMain().getNavigationBar().rightBox.add(this.getSettingButton()); //where 'getSettingButton' predefined by me a button And do this action each time when 'push' event happens (clear 'navigationBar' and add appropriate set of buttons) Of course, I even can implement 'Ext.Panel' with 'layout: card' and set of 'Ext.panel' elements in the 'items' property, each of which will be have unique 'toolbar'. To control the behavior I can use 'setActiveItem' method. But, I think each of these approaches is a bit weird, isn't it? I expected that would be much more natural approach to implement it. Most likely I don't know what I need. Confirm my doubts. What is the best way to do it.

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• ASP.NET MVC unit testing

  - by Simon Lomax

  Hi, I'm getting started with unit testing and trying to do some TDD. I've read a fair bit about the subject and written a few tests. I just want to know if the following is the right approach. I want to add the usual "contact us" facility on my web site. You know the thing, the user fills out a form with their email address, enters a brief message and hits a button to post the form back. The model binders do their stuff and my action method accepts the posted data as a model. The action method would then parse the model and use smtp to send an email to the web site administrator infoming him/her that somebody filled out the contact form on their site. Now for the question .... In order to test this, would I be right in creating an interface IDeliver that has a method Send(emailAddress, message) to accept the email address and message body. Implement the inteface in a concrete class and let that class deal with smtp stuff and actually send the mail. If I add the inteface as a parameter to my controller constructor I can then use DI and IoC to inject the concrete class into the controller. But when unit testing I can create a fake or mock version of my IDeliver and do assertions on that. The reason I ask is that I've seen other examples of people generating interfaces for SmtpClient and then mocking that. Is there really any need to go that far or am I not understanding this stuff?

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• Delphi Unicode String Type Stored Directly at its Address (or "Unicode ShortString")

  - by Andreas Rejbrand

  I want a string type that is Unicode and that stores the string directly at the adress of the variable, as is the case of the (Ansi-only) ShortString type. I mean, if I declare a S: ShortString and let S := 'My String', then, at @S, I will find the length of the string (as one byte, so the string cannot contain more than 255 characters) followed by the ANSI-encoded string itself. What I would like is a Unicode variant of this. That is, I want a string type such that, at @S, I will find a unsigned 32-bit integer (or a single byte would be enough, actually) containing the length of the string in bytes (or in characters, which is half the number of bytes) followed by the Unicode representation of the string. I have tried WideString, UnicodeString, and RawByteString, but they all appear only to store an adress at @S, and the actual string somewhere else (I guess this has do do with reference counting and such). Update: The most important reason for this is probably that it would be very problematic if sizeof(string) were variable. I suspect that there is no built-in type to use, and that I have to come up with my own way of storing text the way I want (which actually is fun). Am I right? Update I will, among other things, need to use these strings in packed records. I also need manually to read/write these strings to files/the heap. I could live with fixed-size strings, such as <= 128 characters, and I could redesign the problem so it will work with null-terminated strings. But PChar will not work, for sizeof(PChar) = 1 - it's merely an address. The approach I eventually settled for was to use a static array of bytes. I will post my implementation as a solution later today.

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• bind event handler on keydown listen function JavaScript jQuery

  - by user1644123

  I am trying to bind a handler to an event. The event is a keydown function. The handler will listen for hit variables to produce one of two conditions. The 1st condition (odd number of hits) will perform 1 function, the 2nd (even number of hits) will perform another function. To elaborate, the 1st function will scroll to one element, the 2nd will scroll to another element. My syntax may be the wrong approach, but it works for the 1st condition, but not the 2nd. I think I have the conditional statement in the wrong place. How can I rewrite this to work as intended? Thank you kindly, in advance! $(document).keydown(function(e) { switch (e.which) { case 37: break; case 38: break; case 39: break; case 40: //bottom arrow key var hits = 0; if (hits % 2 !== 0) { $('#wrap').animate({ scrollTop: $("#scrollToHere").offset().top }, 2800); } else { $('#wrap').animate({ scrollTop: $("#scroll2ToHere").offset().top }, 2800); } hits++; return false; break; } })? *I moved "var hits = 0;" to the top, but it only works! But is there a way I can reset the whole thing after every two hits? I want to reset because when there is a bug and if I press a 3rd time it scrolls to the very top of the page, where there is no element to make it scroll to the top. Why would it scroll to the top of the page if I never scripted it to do so?? *

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• rails: has_many :through validation?

  - by ramonrails

  Rails 2.1.0 (Cannot upgrade for now due to several constraints) I am trying to achieve this. Any hints? A project has many users through join model A user has many projects through join model Admin class inherits User class. It also has some Admin specific stuff. Admin like inheritance for Supervisor and Operator Project has one Admin, One supervisor and many operators. Now I want to 1. submit data for project, admin, supervisor and operator in a single project form 2. validate all and show errors on the project form. Project has_many :projects_users ; has_many :users, :through => :projects_users User has_many :projects_users ; has_many :projects, :through => :projects_users ProjectsUser = :id integer, :user_id :integer, :project_id :integer, :user_type :string ProjectUser belongs_to :project, belongs_to :user Admin < User # User has 'type:string' column for STI Supervisor < User Operator < User Is the approach correct? Any and all suggestions are welcome.

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• Closing Connections on asynchronous messaging in JMS

  - by The Elite Gentleman

  Hi Everyone! I have created a JMS wrapper (similar to Springs JmsTemplate since I'm not using Springs) and I was wondering: If I setup asynchronous messaging, when is a good time to close connections and JMS relates resources (so that the Connection Factory in the Resource Pool can be available)? Thanks Here's the source code for receiving JMS messages public Message receive() throws JMSException { QueueConnection connection = null; QueueSession session = null; QueueReceiver consumer = null; try { // TODO Auto-generated method stub connection = factory.createQueueConnection(); if (connection != null && getExceptionListener() != null) { connection.setExceptionListener(getExceptionListener()); } session = connection.createQueueSession(isSessionTransacted(), getAcknowledgeMode()); consumer = session.createReceiver(queue); if (getMessageListener() != null) { consumer.setMessageListener(getMessageListener()); } //Begin connection.start(); if (getMessageListener() == null) { return null; } return receive(session, consumer); } catch (JMSException e) { // TODO: handle exception logger.error(e.getLocalizedMessage(), e); throw e; } finally { JMSUtil.closeMessageConsumer(consumer); JMSUtil.closeSession(session, false); //false = don't commit. JMSUtil.closeConnection(connection, true); //true = stop before close. } As you can see, if getMessageListener() != null then apply it to the MessageConsumer. Am I doing this correctly? The same approach has also been taken for JMS Topic.

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• Core Data, Bindings, value transformers : crash when saving

  - by Gael

  Hi, I am trying to store a PNG image in a core data store backed by an sqlite database. Since I intend to use this database on an iPhone I can't store NSImage objects directly. I wanted to use bindings and an NSValueTransformer subclass to handle the transcoding from the NSImage (obtained by an Image well on my GUI) to an NSData containing the PNG binary representation of the image. I wrote the following code for the ValueTransformer : + (Class)transformedValueClass { return [NSImage class]; } + (BOOL)allowsReverseTransformation { return YES; } - (id)transformedValue:(id)value { if (value == nil) return nil; return [[[NSImage alloc] initWithData:value] autorelease]; } - (id)reverseTransformedValue:(id)value { if (value == nil) return nil; if(![value isKindOfClass:[NSImage class]]) { NSLog(@"Type mismatch. Expecting NSImage"); } NSBitmapImageRep *bits = [[value representations] objectAtIndex: 0]; NSData *data = [bits representationUsingType:NSPNGFileType properties:nil]; return data; } The model has a transformable property configured with this NSValueTransformer. In Interface Builder a table column and an image well are both bound to this property and both have the proper value transformer name (an image dropped in the image well shows up in the table column). The transformer is registered and called every time an image is added or a row is reloaded (checked with NSLog() calls). The problem arises when I am trying to save the managed objects. The console output shows the error message : [NSImage length]: unrecognized selector sent to instance 0x1004933a0 It seems like core data is using the value transformer to obtain the NSImage back from the NSData and then tries to save the NSImage instead of the NSData. There are probably workarounds such as the one presented in this post but I would really like to understand why my approach is flawn. Thanks in advance for your ideas and explanations.

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• Benefits of migrating my work to a new web development framework?

  - by John

  When I first started programming with PHP, I was ignorant of other php frameworks (like code igniter, cake php, etc...). So I fell into the trap of re-inventing wheels, which had the benefit of being "fun" and "educational". Overtime, I discovered other open source products that I found useful, like smarty templating engine, jquery library, tcpdf library, fdf etc...so I started bundling these technologies along with things I've built over the years into a LAMP development framework to make life easier for myself. This pass year, I've been having fun developing on the code igniter framework. It does many of the things I do in my framework. Coding in CI feels natural because the MVC and ORM feels similar to the MVC and ORM of my framework. So now I'm contemplating migrating a lot of the plugins in my framework over to CI. The pros and cons I can think of for such a project are: Pros: benefit from the vast community of CI developers lots of other developers will be familiar with it better documentation Cons: I've built a lot of useful plugins against my own framework, and it will take a lot of time to move even just the essential ones at the moment, I still, work faster against my own framework than CI, just because I'm more familiar with it even if I did migrate to CI, there will always be newer and better frameworks in the near future, and i'll be contemplating this scenario again So my question is the following: perhaps I should leave my old framework as is, and for each new project I receive, I make a decision on whether the requirements are best served by developing with CI or my own framework. Is this the right approach?

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• PHPUnit: Testing if a protected method was called

  - by Luiz Damim

  I´m trying to test if a protected method is called in a public interface. <?php abstract class SomeClassAbstract { abstract public foo(); public function doStuff() { $this->_protectedMethod(); } protected function _protectedMethod(); { // implementation is irrelevant } } <?php class MyTest extends PHPUnit_Framework_TestCase { public function testCalled() { $mock = $this->getMockForAbstractClass('SomeClass'); $mock->expects($this->once()) ->method('_protectedMethod'); $mock->doStuff(); } } I know it is called correctly, but PHPUnit says its never called. The same happens when I test the other way, when a method is never called: <?php abstract class AnotherClassAbstract { abstract public foo(); public function doAnotherStuff() { $this->_loadCache(); } protected function _loadCache(); { // implementation is irrelevant } } <?php class MyTest extends PHPUnit_Framework_TestCase { public function testCalled() { $mock = $this->getMockForAbstractClass('AnotherClass'); $mock->expects($this->once()) ->method('_loadCache'); $mock->doAnotherStuff(); } } The method is called but PHPUnit says that it is not. What I´m doing wrong? Edit I wasn´t declaring my methods with double colons, it was just for denoting that it was a public method (interface). Updated to full class/methods declarations. Edit 2 I should have said that I´m testing some method implementations in an abstract class (edited the code to reflect this). Since I can not instantiate the class, how can I test this? I´m thinking in creating an SomeClassSimple extending SomeClassAbstract and testing this one instead. Is it the right approach?

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• .NET How would I build a DAL to meet my requirments?

  - by Jonno

  Assuming that I must deploy an asp.net app over the following 3 servers: 1) DB - not public 2) 'middle' - not public 3) Web server - public I am not allowed to connect from the web server to the DB directly. I must pass through 'middle' - this is purely to slow down an attacker if they breached the web server. All db access is via stored procedures. No table access. I simply want to provide the web server with a ado dataset (I know many will dislike this, but this is the requirement). Using asmx web services - it works, but XML serialisation is slow and it's an extra set of code to maintain and deploy. Using a ssh/vpn tunnel so that the one connects to the db 'via' the middle server, seems to remove any possible benefit of maintaining 'middle'. Using WCF binary/tcp removes the XML problem, but still there is extra code. Is there an approach that provides the ease of ssh/vpn, but the potential benefit of having the dal on the middle server? Many thanks.

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• Need advice on comparing the performance of 2 equivalent linq to sql queries

  - by uvita

  I am working on tool to optimize linq to sql queries. Basically it intercepts the linq execution pipeline and makes some optimizations like for example removing a redundant join from a query. Of course, there is an overhead in the execution time before the query gets executed in the dbms, but then, the query should be processed faster. I don't want to use a sql profiler because I know that the generated query will be perform better in the dbms than the original one, I am looking for a correct way of measuring the global time between the creation of the query in linq and the end of its execution. Currently, I am using the Stopwatch class and my code looks something like this: var sw = new Stopwatch(); sw.Start(); const int amount = 100; for (var i = 0; i < amount; i++) { ExecuteNonOptimizedQuery(); } sw.Stop(); Console.Writeline("Executing the query {2} times took: {0}ms. On average, each query took: {1}ms", sw.ElapsedMilliseconds, sw.ElapsedMilliseconds / amount, amount); Basically the ExecutenNonOptimizedQuery() method creates a new DataContext, creates a query and then iterates over the results. I did this for both versions of the query, the normal one and the optimized one. I took the idea from this post from Frans Bouma. Is there any other approach/considerations I should take? Thanks in advance!

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• proper use of volatile keyword

  - by luke

  I think i have a pretty good idea about the volatile keyword in java, but i'm thinking about re-factoring some code and i thought it would be a good idea to use it. i have a class that is basically working as a DB Cache. it holds a bunch of objects that it has read from a database, serves requests for those objects, and then occasionally refreshes the database (based on a timeout). Heres the skeleton public class Cache { private HashMap mappings =....; private long last_update_time; private void loadMappingsFromDB() { //.... } private void checkLoad() { if(System.currentTimeMillis() - last_update_time > TIMEOUT) loadMappingsFromDB(); } public Data get(ID id) { checkLoad(); //.. look it up } } So the concern is that loadMappingsFromDB could be a high latency operation and thats not acceptable, So initially i thought that i could spin up a thread on cache startup and then just have it sleep and then update the cache in the background. But then i would need to synchronize my class (or the map). and then i would just be trading an occasional big pause for making every cache access slower. Then i thought why not use volatile i could define the map reference as volatile private volatile HashMap mappings =....; and then in get (or anywhere else that uses the mappings variable) i would just make a local copy of the reference: public Data get(ID id) { HashMap local = mappings; //.. look it up using local } and then the background thread would just load into a temp table and then swap the references in the class HashMap tmp; //load tmp from DB mappings = tmp;//swap variables forcing write barrier Does this approach make sense? and is it actually thread-safe?

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• http-post request for a long String in iOS

  - by onkar

  I am looking to send a very long String, which is an image that is encoded into a String. I need to send that information using POST method. I have implemented the same in Android using key-value pair, I need to implement the same in iOS using key-value pair. Please help me with useful resources/approach. EDIT 1 What have I tried [dictionnary setObject:@"admin" forKey:@"username"]; [dictionnary setObject:@"123123" forKey:@"password"]; NSError *error = nil; NSData *jsonData = [NSJSONSerialization dataWithJSONObject:dictionnary options:kNilOptions error:&error]; NSString *urlString = @"MY CALL URL"; NSURL *url = [NSURL URLWithString:urlString]; NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:url]; [request setHTTPMethod:@"POST"]; [request setHTTPBody:jsonData]; NSURLResponse *response = NULL; NSError *requestError = NULL; NSData *responseData = [NSURLConnection sendSynchronousRequest:request returningResponse:&response error:&requestError]; NSLog(@"response is obtained"); NSString *responseString = [[NSString alloc] initWithData:responseData encoding:NSUTF8StringEncoding] ; NSLog(@"%@", responseString); EDIT 2 Error I am getting Request Error Error Domain=kCFErrorDomainCFNetwork Code=303 "The operation couldn’t be completed. (kCFErrorDomainCFNetwork error 303.)" UserInfo=0x7ba0120 {NSErrorFailingURLKey=http://yahoo.com/, NSErrorFailingURLStringKey=http://yahoo.com/}

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• Core principles, rules, and habits for CS students

  - by Asad Butt

  No doubt there is a lot to read on blogs, in books, and on Stack Overflow, but can we identify some guidelines for CS students to use while studying? For me these are: Finish your course books early and read 4-5 times more material relative to your course work. Programming is the one of the fastest evolving professions. Follow the blogs on a daily basis for the latest updates, news, and technologies. Instead of relying on assignments and exams, do at least one extra, non-graded, small to medium-sized project for every programming course. Fight hard for internships or work placements even if they are unpaid, since 3 months of work 1 year at college. Practice everything, every possible and impossible way. Try doing every bit of your assignments project yourself; i.e. fight for every inch. Rely on documentation as the first source for help and samples, Google, and online forums as the last source. Participate often in online communities and forums to learn the best possible approach for every solution to your problem. (After doing your bit.) Make testing one of your habits as it is getting more important everyday in programming. Make writing one of your habits. Write something productive once or twice a week and publish it.

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