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• Scalability 101: How can I design a scalable web application using PHP?

  - by Legend

  I am building a web-application and have a couple of quick questions. From what I learnt, one should not worry about scalability when initially building the app and should only start worrying when the traffic increases. However, this being my first web-application, I am not quite sure if I should take an approach where I design things in an ad-hoc manner and later "fix" them. I have been reading stories about how people start off with an app that gets millions of users in a week or two. Not that I will face the same situation but I can't help but wonder, how do these people do it? Currently, I bought a shared hosting account on Lunarpages and that got me started in building and testing the application. However, I am interested in learning how to build the same application in a scalable-manner using the cloud, for instance, Amazon's EC2. From my understanding, I can see a couple of components: There is a load balancer that first receives requests and then decides where to route each request This request is then handled by a server replica that then processes the request and updates (if required) the database and sends back the response to the client If a similar request comes in, then a caching mechanism like memcached kicks into picture and returns objects from the cache A blackbox that handles database replication Specifically, I am trying to do the following: Setting up a load balancer (my homework revealed that HAProxy is one such load balancer) Setting up replication so that databases can be synchronized Using memcached Configuring Apache to work with multiple web servers Partitioning application to use Amazon EC2 and Amazon S3 (my application is something that will need great deal of storage) Finally, how can I avoid burning myself when using Amazon services? Because this is just a learning phase, I can probably do with 2-3 servers with a simple load balancer and replication but until I want to avoid paying loads of money accidentally. I am able to find resources on individual topics but am unable to find something that starts off from the big picture. Can someone please help me get started?

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• Questions on Juval Lowy's IDesign C# Coding Standard

  - by Jan

  We are trying to use the IDesign C# Coding standard. Unfortunately, I found no comprehensive document to explain all the rules that it gives, and also his book does not always help. Here are the open questions that remain for me (from chapter 2, Coding Practices): No. 26: Avoid providing explicit values for enums unless they are integer powers of 2 No. 34: Always explicitly initialize an array of reference types using a for loop No. 50: Avoid events as interface members No. 52: Expose interfaces on class hierarchies No. 73: Do not define method-specific constraints in interfaces No. 74: Do not define constraints in delegates Here's what I think about those: I thought that providing explicit values would be especially useful when adding new enum members at a later point in time. If these members are added between other already existing members, I would provide explicit values to make sure the integer representation of existing members does not change. No idea why I would want to do this. I'd say this totally depends on the logic of my program. I see that there is alternative option of providing "Sink interfaces" (simply providing already all "OnXxxHappened" methods), but what is the reason to prefer one over the other? Unsure what he means here: Could this mean "When implementing an interface explicitly in a non-sealed class, consider providing the implementation in a protected virtual method that can be overridden"? (see Programming .NET Components 2nd Edition, end of chapter “Interfaces and Class Hierarchies”). I suppose this is about providing a "where" clause when using generics, but why is this bad on an interface? I suppose this is about providing a "where" clause when using generics, but why is this bad on a delegate?

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• How do I correctly reference georss: point in my xsd?

  - by Chris Hinch

  I am putting together an XSD schema to describe an existing GeoRSS feed, but I am stumbling trying to use the external georss.xsd to validate an element of type georss:point. I've reduced the problem to the smallest components thusly: XML: <?xml version="1.0" encoding="utf-8"?> <this> <apoint>45.256 -71.92</apoint> </this> XSD: <xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema" xmlns:georss="http://www.georss.org/georss"> <xs:import namespace="http://www.georss.org/georss" schemaLocation="http://georss.org/xml/1.1/georss.xsd"/> <xs:element name="this"> <xs:complexType> <xs:sequence> <xs:element name="apoint" type="georss:point"/> </xs:sequence> </xs:complexType> </xs:element> </xs:schema> If I make apoint type "xs: string" instead of "georss: point", the XML validates happily against the XSD, but as soon as I reference an imported type (georss: point), my XML validator (Notepad++ | XML Tools) "cannot parse the schema". What am I doing wrong?

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• Best practice for managing changes to 3rd party open source libraries?

  - by Jeff Knecht

  On a recent project, I had to modify an open source library to address a functional deficiency. I followed the SVN best practice of creating a "vendor source" repository and made my changes there. I also submitted the patch to the mailing list of that project. Unfortunately, the project only has a couple of maintainers and they are very slow to commit updates. At some point, I expect the library to be updated, and I expect that my project will want to use the upgraded library. But now I have a potential problem... I don't know whether my patch will have been applied to this future release of the 3rd party library. I also don't know whether my patch will even still be compatible with the internal implementation of the upgraded components. And in all likelihood, someone else will be maintaining my project by that point. Should I name the library in a special way so it is clear that we made special modifications (eg. commons-lang-2.x-for-my-project.jar)? Should I just document the patch and reference the SVN location and a link to the mailing list item in a README? No option that I can think of seems to be fool-proof in an upgrade scenario. What is the best practice for this?

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• Implemeting web-based autocomplete for structured input

  - by ravigad

  I am looking to implement web-based autocomplete for structured commands. So, for example, suppose I was trying to implement a web-based Windows command line with autocomplete, in such a case I would want to suggest all the available commands, then, once a user selects a command, all the options for that command, then if a user enters a switch (say '-' dash or '/' slash) then offer all the switches for that command and all the relevant values that can follow, and so on. All from the same text input box. If you have used version 4.0 of JIRA, I am thinking of something similar to the JQL search input box that they have implemented. I have not managed to find any tutorials that look at this scenario end-to-end (which is a shame, because it would be great to see more applications that do this). What I am looking for is some guidance on the steps needed to implement this solution: Do you have any experience implementing such a solution and if so what components did you use? Would you use a framework such as ANTLR to provide the available options to the end user? If not what would do? Sorry for raising such a general question, but my main problem is working out how the pieces fit together as opposed to, say, how to do autocomplete or how to parse/tokenize an input command...

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• Looking for Simplified Overview of EJB3

  - by sdoca

  Hi I'm looking for a simplified overview of EJB3 components. I seem to understand most of the pieces of the puzzle, but can't quite get them to fit together in my brain as a full picture. I've developed numerous web applications (wars) that have been deployed on Tomcat before, but not a full-fledged EE application (ear). I would like the overview to be as generic as possible. I'm not looking for a tutorial on how to set up EJB3 on Glassfish built in NetBeans or some other vendor specific tutorial that's more about the IDE than the technology. I keep reading about Java, ejb-jar, web and ear modules but am not clear on what these different modules contain and how to use them to put together my app. In my case, I want to write a simple database CRUD web application. The first step is simple; create entity classes that model the database tables my app will be using. I plan on using annotations. Should I create a jar that contains just these enity classes? Is this the ejb-jar module (sometimes referred to as the Java module)? Next, I'll need some business logic classes that make use of the entity classes. These are the session beans (stateless or stateful) correct? Should these be packaged in the same jar as the entity classes or a separate jar? Finally, I'll need some sort of web interface (I'll be creating a JSF portlet) application that makes use of the both the session and entity beans. Together with the above jar(s), this will be my war? Assuming the above to be correct, what is involved in creating an ear? Forgive me if this post is vague, but I'm having a hard time defining what it is I don't understand. Thanks for any help!

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• Adapting the width of a Flexs 3 DataGridColumn to the content of its ItemRenderer ?

  - by phtrivier

  I have the following scenario : A Flex 3 DataGrid is sitting here At runtime, a column is added to this grid The column has a custom ItemRenderer The ItemRenderer inherits from HBox, and adds a few items to the HBOx dynamically My problem is that the width of the column doesn't change. As a consequence, my column stays small, and an ugly horizontal scrollbar is displayed in the line, instead of my content (which is completely unreadable). I would like the column to adapt its width to the content of the HBox in the ItemRenderer. I tried the following : Setting the 'percentWidth' of the ItemRenderer to '100' Invalidating the properties of the ItemRenderer after adding the items The only thing that has a "visible" effect it to force the width of the DataGridColumn. Obviously this is not acceptable since I'm dynamically adding components to the ItemRenderer, and I don't know how many or how big they are. Besides, when I am in the ItemRenderer, I have no access to the column itself (or do I ?) so I cannot force the size of the column from here. So is there a way around this ? Would AdvancedDataGrid help here (notwhistanding the fact that I cannot really use it for other reasons ...) Thanks PH

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• Best practice- How to team-split a django project while still allowing code reusal

  - by Infinity

  I know this sounds kind of vague, but please let me explain- I'm starting work on a brand new project, it will have two main components: "ACME PRODUCT" (think Gmail, Meebo, etc), and "THE SITE" (help, information, marketing stuff, promotional landing pages, etc lots of marketing-induced cruft). So basically the url /acme/* will load stuff in the uber cool ajaxy application, and every other URI will load stuff in the other site. Problem: "THE SITE" component is out of my hands, and will be handled by a consultants team that will work closely with marketing, And I and my team will work solely on the ACME PRODUCT. Question: How to set up the django project in such a way that we can have: Seperate releases. (They can push new marketing pages and functionality without having to worry about the state of our code. Maybe even separate Subversion "projects") Minimize impact (on our product) of whatever flying-unicorns-hocus-pocus the other team codes into the site. Still allow some code reusal. My main concern is that the ACME product needs to be rock solid, and therefore needs to be somewhat isolated of whatever mistakes/code bloopers the consultants make in their marketing side of the site. How have you handled this? Any ideas? Thanks!

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• "java.lang.OutOfMemoryError: Java heap space" in image and array storage

  - by totalconscience

  I am currently working on an image processing demonstration in java (Applet). I am running into the problem where my arrays are too large and I am getting the "java.lang.OutOfMemoryError: Java heap space" error. The algorithm I run creates an NxD float array where: N is the number of pixel in the image and D is the coordinates of each pixel plus the colorspace components of each pixel (usually 1 for grayscale or 3 for RGB). For each iteration of the algorithm it creates one of these NxD float arrays and stores it for later use in a vector, so that the user of the applet may look at the individual steps. My client wants the program to be able to load a 500x500 RGB image and run as the upper bound. There are about 12 to 20 iterations per run so that means I need to be able to store a 12x500x500x5 float in some fashion. Is there a way to process all of this data and, if possible, how? Example of the issue: I am loading a 512 by 512 Grayscale image and even before the first iteration completes I run out of heap space. The line it points me to is: Y.add(new float[N][D]) where Y is a Vector and N and D are described as above. This is the second instance of the code using that line.

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• Remote interface lookup-problem in Glassfish3

  - by andersmo

  I have deployed a war-file, with actionclasses and a facade, and a jar-file with ejb-components (a stateless bean, a couple of entities and a persistence.xml) on glassfish3. My problem is that i cant find my remote interface to the stateless bean from my facade. My bean and interface looks like: @Remote public interface RecordService {... @Stateless(name="RecordServiceBean", mappedName="ejb/RecordServiceJNDI") public class RecordServiceImpl implements RecordService { @PersistenceContext(unitName="record_persistence_ctx") private EntityManager em;... and if i look in the server.log the portable jndi looks like: Portable JNDI names for EJB RecordServiceBean : [java:global/recordEjb/RecordServiceBean, java:global/recordEjb/RecordServiceBean!domain.service.RecordService]|#] and my facade: ...InitialContext ctx= new InitialContext(); try{ recordService = (RecordService) ctx.lookup("java:global/recordEjb/RecordServiceBean!domain.service.RecordService"); } catch(Throwable t){ System.out.println("ooops"); try{ recordService = (RecordService)ctx.lookup("java:global/recordEjb/RecordServiceImpl"); } catch(Throwable t2){ System.out.println("noooo!"); }... } and when the facade makes the first call this exception occur: javax.naming.NamingException: Lookup failed for 'java:global/recordEjb/RecordServiceBean!domain.service.RecordService' in SerialContext [Root exception is javax.naming.NamingException: ejb ref resolution error for remote business interfacedomain.service.RecordService [Root exception is java.lang.ClassNotFoundException: domain.service.RecordService]] and the second call: javax.naming.NamingException: Lookup failed for 'java:global/recordEjb/RecordServiceBean' in SerialContext [Root exception is javax.naming.NamingException: ejb ref resolution error for remote business interfacedomain.service.RecordService [Root exception is java.lang.ClassNotFoundException: domain.service.RecordService]] I have also tested to inject the bean with the @EJB-annotation: @EJB(name="RecordServiceBean") private RecordService recordService; But that doesnt work either. What have i missed? I tried with an ejb-jar.xml but that shouldnt be nessesary. Is there anyone who can tell me how to fix this problem?

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• rbind.zoo doesn't seem create consistent zoo object

  - by a-or-b

  I want to rbind.zoo two zoo object together. When I was testing I came across the following issue(?)... Note: The below is an example, there is clearly no point to it apart from being illustrative. I have an zoo object, call it, 'X'. I want to break it into two parts and then rbind.zoo them together. When I compare it to the original object then all.equal gives differences. It appears that the '$class' attribute differs, but I can't see how or why. Is I make these xts objects then the all.equal works as expected. i.e. ..... X.date <- as.POSIXct(paste("2003-", rep(1:4, 4:1), "-", sample(1:28, 10, replace = TRUE), sep = "")) X <- zoo(matrix(rnorm(24), ncol = 2), X.date) a <- X[c(1:3), ] # first 3 elements b <- X[c(4:6), ] # second 3 elements c <- rbind.zoo(a, b) # rbind into an object of 6 elements d <- X[c(1:6), ] # all 6 elements all.equal(c, d) # are they equal? ~~~~ all.equal gives me the following difference: "Attributes: < Component 3: Attributes: < Length mismatch: comparison on first 1 components "

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• Calling a WPF Appliaction and modify exposed properties?

  - by Justin

  I have a WPF Keyboard Application, it is developed in such a way that an application could call it and modify its properties to adapt the Keyboard to do what it needs to. Right now I have a file *.Keys.Set which tells the appliaction (on open) to style itself according to that new style. I know this file could be passed as a command line argument into the appliaction. That would not be a problem. My concern is, is thier a way via a managed environment to change the properties of the executable as long as they are exposed properly, an example: 'Creates a new instance of the Keyboard Appliaction Dim e_key as new WpfAppliaction("C:\egt\components\keyboard.exe") 'Sets the style path e_key.SetStylePath("c:\users\joe\apps\me\default.keys.set") e_key.Refresh() 'Applies the style e_key.HideMenu() 'Hides the menu e_key.ShowDeck("PIN") 'Shows the custom "deck" of keyboard keys the developer 'Created in the style appliaction. ''work with events and resposne 'Clear the instance from memory e_key.close e_key.dispose e_key = nothing This would allow my application to become easily accessible to other Touch Screen Application Developers, allowing them to use my key_board and keep the functionality they need. It seems like it might be possible because (name of executable).application shows all the exposed functions, properties, and values. I just have never done this before. Any help would be appreciated, thank you in advance.

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• PHP OO vs Procedure with AJAX

  - by vener

  I currently have a AJAX heavy(almost everything) intranet webapp for a business. It is highly modularized(components and modules ala Joomla), with plenty of folders and files. ~ 80-100 different viewing pages (each very unique in it's own sense) on last count and will likely to increase in the near future. I based around the design around commands and screens, the client request a command and sends the required data and receives the data that is displayed via javascript on the screen. That said, there are generally two types of files, a display files with html, javascript, and a little php for templating. And also a php backend file with a single switch statement with actions such as, save, update and delete and maybe other function. There is very little code reuse. Recently, I have been adding an server sided undo function that requires me to reuse some code. So, I took the chance to try out OOP but I notice that some functions are so simple, that creating a class, retrieving all the data then update all the related rows on the database seems like overkill for a simple action as speed is quite critical. Also I noticed there is only one class in an entire file. So, what if the entire php is a class. So, between creating a class and methods, and using global variables and functions. Which is faster?

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• smart phone UI limitations

  - by Manny

  I would like to know, what limitations there are for how far one can go in terms of replacing UI components of current touch screen smart phones, in particular iPhone, Blackberry and android based phones. What I would like to do is create a custom UI for dialing out and incoming calls. I have some experience with Blackberry development. The theme builder for it, can be used to customize certain items on the incoming call screen, but it doesn't look like that you can increase the size of answer button. I know Blackberry also gives you access to all the phone APIs, but I'm not sure that you can create your own UI that can gain preference over the Blackberry incoming call screen. And if you try to customize the incoming call screen by adding any buttons to it, they would be rendered as pictures. I could possibly design a complete UI for android, since different manufactures have different UI for android based phones. Can I do what I want to do using iPhone, Blackberry or android? Or any other phone for that matter? I am guessing may be for Nokia phones using Qt, but I prefer the 3 platforms I listed. Thanks for all your help.

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• Spring annotation-based container configuration context:include & exclude filters

  - by lisak

  Hey, first off I point to the similar question. I spent more than an hour to set this up, but PathMatchingResourcePatternResolver still scans everything. I have one common.xml (that is imported from specific.xml) and a specific.xml bean definition file. The context is loaded from specific.xml. In common.xml there is this element: <context:component-scan base-package="cz.instance.transl"> <context:exclude-filter type="aspectj" expression="cz.instance.transl.model..* &amp;&amp; cz.instance.transl.service..* &amp;&amp; cz.instance.transl.hooks..*"/> </context:component-scan> Where classes in packages like cz.instance.transl.service.* should not be subject of scanning, but everything else in here cz.instance.transl.* should be scanned through. But PathMatchingResourcePatternResolver marks everything as matching resources. It is the same with regex. BTW: in xml style configuration, one can have many components that share a common.xml beans via "import resource" when loading context. How this is done when Annotation-based container configuration is used ?

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• Acessing a wordpress database from an iPhone App.

  - by Code

  Hi guys, I've been asked to create an app that will get data back from a database where the CMS will be Wordpress. I've never used a CMS so I'm trying to get a (overview)picture in my head of how it could all work and what each of the components would be. And what a CMS actually brings to the party. Creating the app itself is pretty clear. I've done a few already. I've made a database before and shouldnt cause a problem. But what is going to be in the middle between the app and the database? Part A: I'm guessing iphone apps typically would call some php file that's hosted on the server? The php then would make a call to the database and return the data somehow, maybe as xml. But this is really basic and wouldnt require a CMS. Just a database and a phpfile, or am I wrong? Part B: If i wanted to run a check on the database every minute to see if any of the data in database was no longer valid and remove it if needed, that would require somekind of program running on the server. So that program would be Wordpress, since it is managing the content, so a content management system is actually needed and is for these kind of taskes. Am i understanding the role of CMS? Many Thanks, -Code

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• Add Source file link to the default ASP.NET Server Error page?

  - by Max Schilling

  Has anyone ever thought to attempt to modify the default ASP.NET Server error page to provide a link BACK to the error source in Visual Studio? Consider the following standard error page in ASP.NET: Server Error in '/myproject' Application. Invalid object name 'usp_DoSomething'. Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code. Exception Details: System.Data.SqlClient.SqlException: Invalid object name 'usp_DoSomething'. Source Error: Line 4323: cmd.CommandText = "usp_DoSomething"; Line 4324: Line 4325: using (var dr = cmd.ExecuteReader()) Line 4326: { Line 4327: if (dr != null) Source File: c:\development\myproject\myproject.components\providers\sql\sqldataprovider.cs Line: 4325 When an error like this is generated, the HTML has the source back to the file the error occurs in and the line number. Has anyone ever written or thought of writing some mechanism to turn the text into a link back to the error in Visual Studio? I've never seen anything that does it, but it just seems like it would be a helluva nice feature and I think about it in the back of my mind every time an error occurs when I have to manually go find it in the source. It would just be nice to be able to click a link to take me straight there. Anyone written any, or know of any solutions for this. I use Chrome or Firefox as my browsers of choice, but I'd even consider using IE again if someone found a plugin that did this. Thanks, Max

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• OpenGL Pixel Format Attributes (NSOpenGLPixelFormatAttibutes) explanation?

  - by nacho4d

  Hi, I am not new to OpenGL, but not an expert. Many tutorials teach how to draw, 3D, 2D, projections, orthogonal, etc, but How about setting a the view? (NSOpenGLView in Cocoa, Macs). For example I have this: - (id) initWithFrame: (NSRect) frame { GLuint attribs[] = { //PF: PixelAttibutes NSOpenGLPFANoRecovery, NSOpenGLPFAWindow, NSOpenGLPFAAccelerated, NSOpenGLPFADoubleBuffer, NSOpenGLPFAColorSize, 24, NSOpenGLPFAAlphaSize, 8, NSOpenGLPFADepthSize, 24, NSOpenGLPFAStencilSize, 8, NSOpenGLPFAAccumSize, 0, 0 }; NSOpenGLPixelFormat* fmt = [[NSOpenGLPixelFormat alloc] initWithAttributes: (NSOpenGLPixelFormatAttribute*) attribs]; return self = [super initWithFrame:frame pixelFormat: [fmt autorelease]]; } And I don't understand very well their usage, specially when combining them. For example: If I want my view to be capable of full screen should I write NSOpenGLPFAFullScreen only ? or both? (by capable I mean not always in full screen) Regarding Double Buffer, what is this exactly? (Below: Apple's definition) If present, this attribute indicates that only double-buffered pixel formats are considered. Otherwise, only single-buffered pixel formats are considered Regarding Color: if NSOpenGLPFAColorSize is 24 and NSOpenGLPFAColorSize is 8 then it means that alpha and RGB components are treated differently? what happen if I set the former to 32 and the later to 0? Etc, etc,In general how do I learn to set my view from scratch? Thanks in advance. Ignacio.

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• How to avoid GUI freeze when calling Beginthread API?

  - by isa

  Below just a simple race between 2 button in 2 threads, and this will freeze other components on the form. procedure moveButton1(); var I: Integer; begin for I := 0 to 6000 do Form1.Button1.Left := Form1.Button1.Left - 1; Form1.Caption := 'Button1 won!'; EndThread(0); end; procedure moveButton2(); var I: Integer; begin for I := 0 to 6000 do Form1.Button2.Left := Form1.Button2.Left - 1; Form1.Caption := 'Button2 won!'; EndThread(0); end; procedure TForm1.Button3Click(Sender: TObject); var thread1, thread2,tick : Integer; id1, id2 : LongWord; begin thread1 := BeginThread(nil, 0, Addr(moveButton1), nil, 0, id1); thread2 := BeginThread(nil, 0, Addr(moveButton2), nil, 0, id2); CloseHandle(thread1); CloseHandle(thread2); end;

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• data ownership and performance

  - by Ami

  We're designing a new application and we ran into some architectural question when thinking about data ownership. we broke down the system into components, for example Customer and Order. each of this component/module is responsible for a specific business domain, i.e. Customer deals with CRUD of customers and business process centered around customers (Register a n new customer, block customer account, etc.). each module is the owner of a set of database tables, and only that module may access them. if another module needs data that is owned by another module, it retrieves it by requesting it from that module. so far so good, the question is how to deal with scenarios such as a report that needs to show all the customers and for each customer all his orders? in such a case we need to get all the customers from the Customer module, iterate over them and for each one get all the data from the Order module. performance won't be good...obviously it would be much better to have a stored proc join customers table and orders table, but that would also mean direct access to the data that is owned by another module, creating coupling and dependencies that we wish to avoid. this is a simplified example, we're dealing with an enterprise application with a lot of business entities and relationships, and my goal is to keep it clean and as loosely coupled as possible. I foresee in the future many changes to the data scheme, and possibly splitting the system into several completely separate systems. I wish to have a design that would allow this to be done in a relatively easy way. Thanks!

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• cakephp isAuthorized() not being called

  - by Jack B Nimble

  I am trying to use the isAuthorized() method to do a check for an admin flag, but the function never seems to be called. Even when I set the function to always return false, it allows any user. It just seems like it isn't being called. Do I need to do something more than setting $this-Auth-authorize = 'controller' ? from /app/app_controller.php class AppController extends Controller { var $components = array('Auth'); function beforeFilter() { $this->Auth->loginAction = array('controller' => 'users', 'action' => 'login'); $this->Auth->loginRedirect = array('controller' => 'pages', 'display' => 'home'); $this->Auth->logoutRedirect = '/'; $this->Auth->authorize = 'controller'; $this->Auth->userScope = array('User.active' => 1); } function isAuthorized() { if (strpos($this->action, "admin_") != false) { if ($this->Auth->user('isAdmin') == '0') { return false; } } return true; } }

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• What do you call a generalized (non-GUI-related) "Model-View-Controller" architecture?

  - by dcuccia

  I am currently refactoring code that coordinates multiple hardware components for data acquisition, and feeling a bit like I'm recreating the wheel. In particular, an MVC-like pattern seems to be emerging. Except, this has nothing to do with a GUI and I'm worried that I'm forcing this particular pattern where another might be more appropriate. Here's my scenario: Individual hardware "component" classes obey interface contracts for each hardware type. Previously, component instances were orchestrated by a single monolithic InstrumentController class, which relied heavily on configuration + branching logic for executing a specific acquisition sequence. After an iteration, I have a separate controller for each component, with these controllers all managed by a small InstrumentControllerBase (or its derivatives). The composite system will receive "input" either programmatically or via inter-hardware component triggering - in either case these interactions are routed to, and handled by, the appropriate controller. So, I have something that feels MVC-esque, but I don't know if that's because I'm forcing the point. With little direct MVC experience in application development, it's hard to know if I'm just trying to make my scenario fit MVC, where another pattern might be a good alternative or complimentary. My problem is, search results and wiki documentation of these family of patterns seems to immediately drop me into GUI-specific discussions. I understand "M means Model data and the V means View" - but do you call the superset pattern? Component-Commander-Controller? Whence can I exhume examples exemplary?

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• FLEX: how to better align my Tile component to the puppet (and how to solve roll over out effects) ?

  - by Patrick

  hi, At the moment my Puppets are larger on the left if I add them the <mx:Tile> component (with tags): http://dl.dropbox.com/u/72686/puppets.png how can I move my Tile component to the right ? In order to align with the left border of my puppets ? <mx:Tile id="tagsPopup" width="200" visible="false" > <mx:LinkButton label="Tag1" /> <mx:LinkButton label="Tag2" /> <mx:LinkButton label="Tag3" /> <mx:LinkButton label="Tag4" /> </mx:Tile> <mx:VBox verticalGap="0"> <mx:Image id="puppet" source="@Embed(source='../icons/userIcon.png')" /> <mx:Label id="username" text="Nickname" visible="false" fontWeight="bold" /> </mx:VBox> 2nd Question: I want to add objects on top of the puppets, some of them are visible only when the mouse is over, and they are overlying the ones are permanently visible. How do you suggest to implement it ? I was thinking to add in MXML all visible elements and then use Actionscript to add the fade in fade out components. However I just realize it is quite tricky, because I want the user select for example tag1, tag2 and tag3, with the mouse. Instead now they disappear when the mouse rolls out from the puppet image. Any guideline ? thanks

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• boost::asio::io_service throws exception

  - by Ace

  Okay, I seriously cannot figure this out. I have a DLL project in MSVC that is attempting to use Asio (from Boost 1.45.0), but whenever I create my io_service, an exception is thrown. Here is what I am doing for testing purposes: void run() { boost::this_thread::sleep(boost::posix_time::seconds(5)); try { boost::asio::io_service io_service; } catch (std::exception & e) { MessageBox(NULL, e.what(), "Exception", MB_OK); } } BOOL WINAPI DllMain(HINSTANCE hinstDLL, DWORD fdwReason, LPVOID lpvReserved) { if (fdwReason == DLL_PROCESS_ATTACH) { boost::thread thread(run); } return TRUE; } This is what the message box shows: winsock: WSAStartup cannot function at this time because the underlying system it uses to provide network services is currently unavailable Here is what MSDN says about it (error code 10091, WSASYSNOTREADY): Network subsystem is unavailable. This error is returned by WSAStartup if the Windows Sockets implementation cannot function at because the underlying system it uses to provide network services is currently unavailable. Users should check: That the appropriate Windows Sockets DLL file is in the current path. That they are not trying to use more than one Windows Sockets implementation simultaneously. If there is more than one Winsock DLL on your system, be sure the first one in the path is appropriate for the network subsystem currently loaded. The Windows Sockets implementation documentation to be sure all necessary components are currently installed and configured correctly. Yet none of this seems to apply to me (or so I think). Here is my command line: /O2 /GL /D "_WIN32_WINNT=0x0501" /D "_WINDLL" /FD /EHsc /MD /Gy /Fo"Release\" /Fd"Release\vc90.pdb" /W3 /WX /nologo /c /TP /errorReport:prompt If anyone knows what might be wrong, please help me out! Thanks.

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• Set JTabbedPane width to constant

  - by msp

  I'm implementing an UI in Java Swing. Therefore I use a JTabbedPane. The tabbedPane has no components at startup. When i add a tab to the tabbedpane, the width of the tabbedpane increases, when i remove the tab, the width resizes to the width at the startup. This should not happen. The tabbedpane is placed on a JPanel which has a gridbag layout. Layout code: Container contentPane = mainFrame.getContentPane(); contentPane.setLayout( new GridBagLayout() ); GridBagConstraints c = new GridBagConstraints(); // add the component tree initComponentTree(); c.gridx = 0; c.gridy = 0; c.gridheight = 1; c.gridwidth = 1; c.fill = GridBagConstraints.BOTH; c.anchor = GridBagConstraints.LINE_START; c.weightx = 1; c.weighty = 1; contentPane.add( componentTree, c ); // add the tabbed pane initTabbedPane(); c.gridx = 1; c.weightx = 10; contentPane.add( tabbedPane, c ); // add the status panel initStatusPanel(); c.gridx = 0; c.gridy = 1; c.gridwidth = 2; c.fill = GridBagConstraints.HORIZONTAL; c.anchor = GridBagConstraints.LINE_START; c.weightx = 0; c.weighty = 0; contentPane.add( statusPanel, c ); Hope someone can help!

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