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• TypeError: Error #1009 - (Null reference error) With Flash.

  - by Wind Chimez

  I am not an expert in flash, but i do work with AS and tweak Flash projects , though not having deep expertise in it. Currently i need to revamp a flash website done by one another guy, and the code base given to me, upon execution is throwing the following error. "--- TypeError: Error #1009: Cannot access a property or method of a null object reference. at NewSite_fla::MainTimeline/__setProp_ContactOutP1_ContactOut_Contents_0() at NewSite_fla::MainTimeline/frame1() --" The structure of the project is like, it has the different sections split into different movie clips. There is no single main timeline, but click actions on different areas of seperate movie clips will take them between one another. All the AS logic of event handling are written inline in FLA , no seperate Document class exists. Preloader Movie clip is the first one getting loaded. As i understood the error is getting thrown initially itself, and it is not happening due to any Action script logic written inline, because it is throwing error even before hitting the first inline AS code. I am not able to figure Out what exactly it causing the problem, or where to resolve it. I setup the stuff online, for reference if anybody want to take a look at it, and here is the link.You need to have flash debugger turned ON in your browser, if need to see the exception getting triggered. http://tinyurl.com/2alvlfx I really got stuck at this point. Any help will be great.I had not seen the particular solution i am looking for anywhere yet, though Error #1009 is common.

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• How to build Graceful Degradation AJAX web page?

  - by Morgan Cheng

  I want to build web page with "Graceful Degradation". That is, the web page functions even javascript is disabled. Now I have to make design decision on the format of AJAX response. If javascript is disabled, each HTTP request to server will generate HTML as response. The browser refreshes with the returned HTML. That's fine. If javascript is enabled, each AJAX HTTP request to server will generate ... well, JSON or HTML. If it is HTML, it is easy to implement. Just have javascript to replace part of page with the returned HTML. And, in server side, not much code change is needed. If it is JSON, then I have to implement JSON-to-html logic in javascript again which is almost duplicate of server side logic. Duplication is evil. I really don't like it. The benefit is that the bandwidth usage is better than HTML, which brings better performance. So, what's the best solution to Graceful Degradation? AJAX request better to return JSON or HTML?

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• When *not* to use prepared statements?

  - by Ben Blank

  I'm re-engineering a PHP-driven web site which uses a minimal database. The original version used "pseudo-prepared-statements" (PHP functions which did quoting and parameter replacement) to prevent injection attacks and to separate database logic from page logic. It seemed natural to replace these ad-hoc functions with an object which uses PDO and real prepared statements, but after doing my reading on them, I'm not so sure. PDO still seems like a great idea, but one of the primary selling points of prepared statements is being able to reuse them… which I never will. Here's my setup: The statements are all trivially simple. Most are in the form SELECT foo,bar FROM baz WHERE quux = ? ORDER BY bar LIMIT 1. The most complex statement in the lot is simply three such selects joined together with UNION ALLs. Each page hit executes at most one statement and executes it only once. I'm in a hosted environment and therefore leery of slamming their servers by doing any "stress tests" personally. Given that using prepared statements will, at minimum, double the number of database round-trips I'm making, am I better off avoiding them? Can I use PDO::MYSQL_ATTR_DIRECT_QUERY to avoid the overhead of multiple database trips while retaining the benefit of parametrization and injection defense? Or do the binary calls used by the prepared statement API perform well enough compared to executing non-prepared queries that I shouldn't worry about it? EDIT: Thanks for all the good advice, folks. This is one where I wish I could mark more than one answer as "accepted" — lots of different perspectives. Ultimately, though, I have to give rick his due… without his answer I would have blissfully gone off and done the completely Wrong Thing even after following everyone's advice. :-) Emulated prepared statements it is!

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• Creating an Admin directory in Rails

  - by matsko

  I've been developing the CMS backend for a website for a few weeks now. The idea is to craft everything in the backend first so that it can manage the database and information that will be displayed on the main website. As of now, I currently have all my code setup in the normal rails MVC structure. So the users admin is /users and videos is /videos. My plans are to take the code for this and move it to a /admin directory. So the two controllers above would need to be accessed by /admin/users and /admin/videos. I'm not sure how todo the ruote (adding the /admin as a prefix) nor am I sure about how to manage the logic. What I'm thinking of doing is setting up an additional 'middle' controller that somehow gets nested between the ApplicationControler and the targetted controller when the /admin directory is accessed. This way, any additional flags and overloaded methods can be spawned for the /admin section only (I believe I could use a filter too for this). If that were to work, then the next issue would be separating the views logic (but that would just be renaming folders and so on). Either I do it that way or I have two rails instances that share the MVC code between them (and I guess the database too), but I fear that would cause lots of duplication errors. Any ideas as to how I should go about doing this? Many thanks!

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• How would I go about sharing variables in a class with Lua?

  - by Nicholas Flynt

  I'm fairly new to Lua, I've been working on trying to implement Lua scripting for logic in a Game Engine I'm putting together. I've had no trouble so far getting Lua up and running through the engine, and I'm able to call Lua functions from C and C functions from Lua. The way the engine works now, each Object class contains a set of variables that the engine can quickly iterate over to draw or process for physics. While game objects all need to access and manipulate these variables in order for the Game Engine itself to see any changes, they are free to create their own variables, a Lua is exceedingly flexible about this so I don't forsee any issues. Anyway, currently the Game Engine side of things are sitting in C land, and I really want them to stay there for performance reasons. So in an ideal world, when spawning a new game object, I'd need to be able to give Lua read/write access to this standard set of variables as part of the Lua object's base class, which its game logic could then proceed to run wild with. So far, I'm keeping two separate tables of objects in place-- Lua spawns a new game object which adds itself to a numerically indexed global table of objects, and then proceeds to call a C++ function, which creates a new GameObject class and registers the Lua index (an int) with the class. So far so good, C++ functions can now see the Lua object and easily perform operations or call functions in Lua land using dostring. What I need to do now is take the C++ variables, part of the GameObject class, and expose them to Lua, and this is where google is failing me. I've encountered a very nice method here which details the process using tags, but I've read that this method is deprecated in favor of metatables. What is the ideal way to accomplish this? Is it worth the hassle of learning how to pass class definitions around using libBind or some equivalent method, or is there a simple way I can just register each variable (once, at spawn time) with the global lua object? What's the "current" best way to do this, as of Lua 5.1.4?

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• Business Objects - Containers or functional?

  - by Walter

  Where I work, we've gone back and forth on this subject a number of times and are looking for a sanity check. Here's the question: Should Business Objects be data containers (more like DTOs) or should they also contain logic that can perform some functionality on that object. Example - Take a customer object, it probably contains some common properties (Name, Id, etc), should that customer object also include functions (Save, Calc, etc.)? One line of reasoning says separate the object from the functionality (single responsibility principal) and put the functionality in a Business Logic layer or object. The other line of reasoning says, no, if I have a customer object I just want to call Customer.Save and be done with it. Why do I need to know about how to save a customer if I'm consuming the object? Our last two projects have had the objects separated from the functionality, but the debate has been raised again on a new project. Which makes more sense? EDIT These results are very similar to our debates. One vote to one side or another completely changes the direction. Does anyone else want to add their 2 cents? EDIT Eventhough the answer sampling is small, it appears that the majority believe that functionality in a business object is acceptable as long as it is simple but persistence is best placed in a separate class/layer. We'll give this a try. Thanks for everyone's input...

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• ASP.Net MVC vs ASP.Net for Complex workflows

  - by Grant Sutcliffe

  I have just become involved in migrating a series of complex workflows with InfoPath UIs to Web-based UIs. I am new to ASP.Net MVC but have started to evaluate it as the technology versus classic ASP.Net for the job. As is typical of most workflows, in each state there are a number of business rules that determine (a) who can view what content; (2) who can edit what content; (3) what the user action options might be (Edit; Reject; Approve), etc. In essence, there is a lot of logic that needs to be applied to each request before presenting the appropriate view. Being more experienced in ASP.Net, I know that presenting the form(s) as required can be easily achieved through code behind pages (enable / disable / hide fields). I have not seen how this can be achieved with ASP.Net MVC (but am realising that new thinking is required of me when working with MVC - ‘Give only the content on a particular View + limited user action options’). Therefore, if using ASP.Net MVC, it looks like I would need to create a lot of views. Much of the content in each view would be the same. Only field enabled status or buttons would differ in most instances for these views in each state. For example: Step01Initiate (‘Has Save’ button); Step01OriginatorView (has ‘Edit’ Button) ; Step01OriginatorEdit (has ‘Save’ button); Step01Review (has ‘Accept’ / ‘Reject’ buttons); Step01ReviewReject (for reviewer notes; has ‘Save’ / ‘Cancel’ buttons). With workflows of up to six states, this would result in a lot of views. I can see the advantages of choosing ASP.MVC (1) ‘thin’ Views in terms of content; and (2) with logic consolidation in Controllers and different Models. Am I thinking along the right lines in terms of applying the MVC – ‘plenty of views’; or is there a better way to achieve my goal (using ASP.Net MVC or classic ASP.Net)?

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• LINQ query code for complex merging of data.

  - by Stacey

  I've posted this before, but I worded it poorly. I'm trying again with a more well thought out structure. Re-writing this a bit to make it more clear. I have the following code and I am trying to figure out the shorter linq expression to do it 'inline'. Please examine the "Run()" method near the bottom. I am attempting to understand how to join two dictionaries together based on a matching identifier in one of the objects - so that I can use the query in this sort of syntax. var selected = from a in items.List() // etc. etc. select a; This is my class structure. The Run() method is what I am trying to simplify. I basically need to do this conversion inline in a couple of places, and I wanted to simplify it a great deal so that I can define it more 'cleanly'. class TModel { public Guid Id { get; set; } } class TModels : List<TModel> { } class TValue { } class TStorage { public Dictionary<Guid, TValue> Items { get; set; } } class TArranged { public Dictionary<TModel, TValue> Items { get; set; } } static class Repository { static public TItem Single<TItem, TCollection>(Predicate<TItem> expression) { return default(TItem); // access logic. } } class Sample { public void Run() { TStorage tStorage = new TStorage(); // access tStorage logic here. Dictionary<TModel, TValue> d = new Dictionary<TModel, TValue>(); foreach (KeyValuePair<Guid, TValue> kv in tStorage.Items) { d.Add(Repository.Single<TModel, TModels>(m => m.Id == kv.Key),kv.Value); } } }

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• How to write a custom solution using a python package, modules etc

  - by morpheous

  I am writing a packacge foobar which consists of the modules alice, bob, charles and david. From my understanding of Python packages and modules, this means I will create a folder foobar, with the following subdirectories and files (please correct if I am wrong) foobar/ __init__.py alice/alice.py bob/bob.py charles/charles.py david/david.py The package should be executable, so that in addition to making the modules alice, bob etc available as 'libraries', I should also be able to use foobar in a script like this: python foobar --args=someargs Question1: Can a package be made executable and used in a script like I described above? Question 2 The various modules will use code that I want to refactor into a common library. Does that mean creating a new sub directory 'foobar/common' and placing common.py in that folder? Question 3 How will the modules foo import the common module ? Is it 'from foobar import common' or can I not use this since these modules are part of the package? Question 4 I want to add logic for when the foobar package is being used in a script (assuming this can be done - I have only seen it done for modules) The code used is something like: if __name__ == "__main__": dosomething() where (in which file) would I put this logic ?

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• Access ADP - For/Against?

  - by webworm

  I have been tasked with taking an Access 97 application and moving the back-end data to SQL Server while moving the front end to Access 2003 (using Access Data Projects). In the process of this migration the back-end data structures will be changed significantly to support new functionality. If I had my wish we would not be using Access as the front end. I think our application would be much better served by WinForms, WPF, or a web application. We have the time needed to properly plan a business logic layer and implement an excellent solution but powers above me want to stay with Access because that is what they are familiar with. What I could use help with is pros/cons of continuing down this path of Access development. What are some legitimate arguments for and against using Access 2003? Here is what I have come up with so far. Pro Access: Already own Access 2003 licenses Easy GUI development Reports look nice Against Access Having to use VBA (Visual Basic for Applications) ADO vs DAO. Didn't Microsoft change things from Access 2002 to Access 2003? Not tied to Access runtime Choice in front end (WPF, WinForms, even ASP.NET) Maintainability True separation of logic from UI not possible Does Microsoft still support Access ADP? Perhaps there are other issues I am not aware off both for and against Access for application development. I am trying to keep an open mind while at the same time trying to maintain my sanity. I have been using C# since .NET was released and the thought of going back to VBA for six months makes my head hurt. Especially when I feel I could offer so much more if allowed to develop with modern languages and tools?

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• verilog / systemverilog -- What is the behavior of blocking statements across two always blocks?

  - by miles.sherman

  I am wondering about the behavior of the below code. There are two always blocks, one is combinational to calculate the next_state signal, the other is sequential which will perform some logic and determine whether or not to shutdown the system. It does this by setting the shutdown_now signal high and then calling state <= next_state. My question is if the conditions become true that the shutdown_now signal is set (during clock cycle n) in a blocking manner before the state <= next_state line, will the state during clock cycle n+1 be SHUTDOWN or RUNNING? In other words, does the shutdown_now = 1'b1 line block across both state machines since the state signal is dependent on it through the next_state determination? enum {IDLE, RUNNING, SHUTDOWN} state, next_state; logic shutdown_now; // State machine (combinational) always_comb begin case (state) IDLE: next_state <= RUNNING; RUNNING: next_state <= shutdown ? SHUTDOWN : RUNNING; SHUTDOWN: next_state <= SHUTDOWN; default: next_state <= SHUTDOWN; endcase end // Sequential Behavior always_ff @ (posedge clk) begin // Some code here if (/*some condition) begin shutdown_now = 1'b0; end else begin shutdown_now = 1'b1; end state <= next_state; end

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• Problems when handling orientation changes

  - by nixau

  Hi all, I need to handle orientation changes in my Android application. For this purpose I decided to use OrientationEventListener convenience class. But his callback method is given somewhat strange behavior. My application starts in the portrait mode and then eventually switches to the lanscape one. I have some custom code executing in the callback onOrientationChanged method that provides some additional UI handling logic - it has a few calls to findViewById. What is strange is that when switching back from landscape to portrait mode onOrientationChanged callback is called twice, and what's even worse - the second call is dealing with bad Context - findViewById method starts returning null. These calls are made right from the MainThread @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); listener = new OrientationListener(); } @Override protected void onResume() { super.onResume(); // enabling listening listener.enable(); } @Override protected void onPause() { super.onPause(); // disabling listening listener.disable(); } I've replicated the same behavior with a dummy Activity without any logic except for one that deals with orientation hadling. I initiate orientation switch from the Android 2.2 emulator by pressing Ctrl+F11 What could be wrong? Upd: Inner class that implements OrientationEventListener private class OrientationListener extends OrientationEventListener { public OrientationL() { super(getBaseContext()); } @Override public void onOrientationChanged(int orientation) { toString(); } } }

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• what libraries or platforms should I use to build web apps that provide real-time, asynchronous data

  - by Daniel Sterling

  This is a less a question with a simple, practical answer and more a question to foster discussion on the real-time data exchange topic. I'll begin with an example: Google Wave is, at its core, a real-time asynchronous data synchronization engine. Wave supports (or plans to support) concurrent (real-time) document collaboration, disconnected (offline) document editing, conflict resolution, document history and playback with attribution, and server federation. A core part of Wave is the Operational Transformation engine: http://www.waveprotocol.org/whitepapers/operational-transform The OT engine manages document state. Changes between clients are merged and each client has a sane and consistent view of the document at all times; the final document is eventually consistent between all connected clients. My question is: is this system abstract or general enough to be used as a library or generic framework upon which to build web apps that synchronize real-time, asynchronous state in each client? Is the Wave protocol directly used by any current web applications (besides Google's client)? Would it make sense to directly use it for generic state synchronization in a web app? What other existing libraries or frameworks would you consider using when building such a web app? How much code in such an app might be domain-specific logic vs generic state synchronization logic? Or, put another way, how leaky might the state synchronization abstractions be? Comments and discussion welcomed!

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• Avoiding anemic domain model - a real example

  - by cbp

  I am trying to understand Anemic Domain Models and why they are supposedly an anti-pattern. Here is a real world example. I have an Employee class, which has a ton of properties - name, gender, username, etc public class Employee { public string Name { get; set; } public string Gender { get; set; } public string Username { get; set; } // Etc.. mostly getters and setters } Next we have a system that involves rotating incoming phone calls and website enquiries (known as 'leads') evenly amongst sales staff. This system is quite complex as it involves round-robining enquiries, checking for holidays, employee preferences etc. So this system is currently seperated out into a service: EmployeeLeadRotationService. public class EmployeeLeadRotationService : IEmployeeLeadRotationService { private IEmployeeRepository _employeeRepository; // ...plus lots of other injected repositories and services public void SelectEmployee(ILead lead) { // Etc. lots of complex logic } } Then on the backside of our website enquiry form we have code like this: public void SubmitForm() { var lead = CreateLeadFromFormInput(); var selectedEmployee = Kernel.Get<IEmployeeLeadRotationService>() .SelectEmployee(lead); Response.Write(employee.Name + " will handle your enquiry. Thanks."); } I don't really encounter many problems with this approach, but supposedly this is something that I should run screaming from because it is an Anemic Domain Model. But for me its not clear where the logic in the lead rotation service should go. Should it go in the lead? Should it go in the employee? What about all the injected repositories etc that the rotation service requires - how would they be injected into the employee, given that most of the time when dealing with an employee we don't need any of these repositories?

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• How to check for DOM equality with jQuery?

  - by Joseph

  I'm basically building a simple list, and one of the items in the list is selected. I'm accomplishing this by having a "selected" class applied to whichever item I want to have selected. I have two buttons that go forward and backward which traverse this list. However, when the user gets to the first or the last element in the list, I want to do a post back. This is where I'm stuck, because I'm having trouble identifying that the currently selected item is not the first or the last. Simple Example: <div id="list"> <p>item 1</p> <p>item 2</p> <p class="selected">item 3</p> </div> Let's say the user presses the next button, at this point I'm checking for something similar to this: if (jQuery('#list p.selected') == jQuery('#list p:last-child')) //do post back However, this logic is returning false, which leads me to believe I'm approaching this the wrong way. What is the best way for me to check for this kind of logic using jQuery?

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• Is It Incorrect to Make Domain Objects Aware of The Data Access Layer?

  - by Noah Goodrich

  I am currently working on rewriting an application to use Data Mappers that completely abstract the database from the Domain layer. However, I am now wondering which is the better approach to handling relationships between Domain objects: Call the necessary find() method from the related data mapper directly within the domain object Write the relationship logic into the native data mapper (which is what the examples tend to do in PoEAA) and then call the native data mapper function within the domain object. Either it seems to me that in order to preserve the 'Fat Model, Skinny Controller' mantra, the domain objects have to be aware of the data mappers (whether it be their own or that they have access to the other mappers in the system). Additionally it seems that Option 2 unnecessarily complicates the data access layer as it creates table access logic across multiple data mappers instead of confining it to a single data mapper. So, is it incorrect to make the domain objects aware of the related data mappers and to call data mapper functions directly from the domain objects? Update: These are the only two solutions that I can envision to handle the issue of relations between domain objects. Any example showing a better method would be welcome.

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• Using DTOs and BOs

  - by ryanzec

  One area of question for me about DTOs/BOs is about when to pass/return the DTOs and when to pass/return the BOs. My gut reaction tells me to always map NHibernate to the DTOs, not BOs, and always pass/return the DTOs. Then whenever I needed to perform business logic, I would convert my DTO into a BO. The way I would do this is that my BO would have a have a constructor that takes a parameter that is the type of my interface (that defines the required fields/properties) that both my DTO and BO implement as the only argument. Then I would be able to create my BO by passing it the DTO in the constructor (since both with implement the same interface, they both with have the same properties) and then be able to perform my business logic with that BO. I would then also have a way to convert a BO to a DTO. However, I have also seen where people seem to only work with BOs and only work with DTOs in the background where to the user, it looks like there are no DTOs. What benefits/downfalls are there with this architecture vs always using BO's? Should I always being passing/returning either DTOs or BOs or mix and match (seems like mixing and matching could get confusing)?

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• PHP: Aggregate Model Classes or Uber Model Classes?

  - by sunwukung

  In many of the discussions regarding the M in MVC, (sidestepping ORM controversies for a moment), I commonly see Model classes described as object representations of table data (be that an Active Record, Table Gateway, Row Gateway or Domain Model/Mapper). Martin Fowler warns against the development of an anemic domain model, i.e. a class that is nothing more than a wrapper for CRUD functionality. I've been working on an MVC application for a couple of months now. The DBAL in the application I'm working on started out simple (on account of my understanding - oh the benefits of hindsight), and is organised so that Controllers invoke Business Logic classes, that in turn access the database via DAO/Transaction Scripts pertinent to the task at hand. There are a few "Entity" classes that aggregate these DAO objects to provide a convenient CRUD wrapper, but also embody some of the "behaviour" of that Domain concept (for example, a user - since it's easy to isolate). Taking a look at some of the code, and thinking along refactoring some of the code into a Rich Domain Model, it occurred to me that were I to try and wrap the CRUD routines and behaviour of say, a Company into a single "Model" class, that would be a sizeable class. So, my question is this: do Models represent domain objects, business logic, service layers, all of the above combined? How do you go about defining the responsibilities for these components?

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• TypeError: Error #1009 - (Null reference error) With Flash.

  - by Wind Chimez

  I am not an expert in flash, but i do work with AS and tweak Flash projects , though not having deep expertise in it. Currently i need to revamp a flash website done by one another guy, and the code base given to me, upon execution is throwing the following error. "--- TypeError: Error #1009: Cannot access a property or method of a null object reference. at NewSite_fla::MainTimeline/__setProp_ContactOutP1_ContactOut_Contents_0() at NewSite_fla::MainTimeline/frame1() --" The structure of the project is like, it has the different sections split into different movie clips. There is no single main timeline, but click actions on different areas of seperate movie clips will take them between one another. All the AS logic of event handling are written inline in FLA , no seperate Document class exists. Preloader Movie clip is the first one getting loaded. As i understood the error is getting thrown initially itself, and it is not happening due to any Action script logic written inline, because it is throwing error even before hitting the first inline AS code. I am not able to figure Out what exactly it causing the problem, or where to resolve it. I really got stuck at this point. Any help will be great.I had not seen the particular solution i am looking for anywhere yet, though Error #1009 is common. I uploaded the fla, here ( http://tinyurl.com/249e95p ), for reference.It may not be working , since the included/refered video files and all are not there, but reviwing the action code/movie clips will be possible. Please let me know if somebody will be able to trace the issue exactly.

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• Beginner's guide for rails

  - by piemesons

  Hello friends i need a book/ tutorials for rails without using scoffold. All the books mentioned in the other questions are creating some depot application or etc using scaffold and then explaining things. I believe in the thing that creating big depot is worthless when you are not getting anything. All of my frnds are suggesting me to go for this pragmatic book. look i understand the book is good but i m not getting the proper things. I got the logic cause i m good in php doctrine. asp.net c c++ so i m getting the things but i m not feeling confident. I want to have a another book. Can anybody suggest me some other books. I m saying this cause it really feels good when u create a simple form and insert the values in db and u can retreive those values and MOST IMP you can explain the whole logic of the that small form application instaed of that colorfull Depot application in which things are done with scaffold and u r not getting the thing and u are confused abt the real picture.

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• How would the 'Model' in a Rails-type webapp be implemented in a functional programming langauge?

  - by ceptorial

  In MVC web development frameworks such as Ruby on Rails, Django, and CakePHP, HTTP requests are routed to controllers, which fetch objects which are usually persisted to a backend database store. These objects represent things like users, blog posts, etc., and often contain logic within their methods for permissions, fetching and/or mutating other objects, validation, etc. These frameworks are all very much object oriented. I've been reading up recently on functional programming and it seems to tout tremendous benefits such as testability, conciseness, modularity, etc. However most of the examples I've seen for functional programming implement trivial functionality like quicksort or the fibonnacci sequence, not complex webapps. I've looked at a few 'functional' web frameworks, and they all seem to implement the view and controller just fine, but largely skip over the whole 'model' and 'persistence' part. (I'm talking more about frameworks like Compojure which are supposed to be purely functional, versus something Lift which conveniently seems to use the OO part of Scala for the model -- but correct me if I'm wrong here.) I haven't seen a good explanation of how functional programming can be used to provide the metaphor that OO programming provides, i.e. tables map to objects, and objects can have methods which provide powerful, encapsulated logic such as permissioning and validation. Also the whole concept of using SQL queries to persist data seems to violate the whole 'side effects' concept. Could someone provide an explanation of how the 'model' layer would be implemented in a functionally programmed web framework?

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• Can I use a specific model from within a behavior in CakePHP?

  - by Paul Willy

  I'm trying to write a behavior that will give my models access to a simple workflow engine I've devised. The workflow engine itself works as a CakePHP model, with workflow data stored in the database just as any other model data is stored. Basically what I want to do is have the behavior use the workflow model whenever an action is called on the base model. For example, if the edit() action is executed for Posts, then the Post (with the behavior attached) will trigger the workflow behavior with its own model name, action, and id as arguments (e.g. [Post, edit, 1]). Then the behavior will invoke the functionality of the Workflow model, which has a record for what to do when edit is run on Posts (e.g. send e-mail to users who are subscribed to that post) and will carry that out. My question is, what is the proper way to invoke model/controller methods from within the behavior? The model to be used from within the behavior will always be Workflow, but the behavior should be usable from basically any model (aside from Workflow itself). I know I could run SQL queries directly from the behavior, but of course this is not the Cake way :-) Or, am I going about this in the wrong way? I want to store a certain amount of logic in the database so that it is easily configurable by different users, and not have endless configuration checks within the model/controller logic itself so that workflow steps can be easily added/changed/removed in the future.

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• WriteableBitmap failing badly, pixel array very inaccurate

  - by dawmail333

  I have tried, literally for hours, and I have not been able to budge this problem. I have a UserControl, that is 800x369, and it contains, simply, a path that forms a worldmap. I put this on a landscape page, then I render it into a WriteableBitmap. I then run a conversion to turn the 1d Pixels array into a 2d array of integers. Then, to check the conversion, I wire up the custom control's click command to use the Point.X and Point.Y relative to the custom control in the newly created array. My logic is thus: wb = new WriteableBitmap(worldMap, new TranslateTransform()); wb.Invalidate(); intTest = wb.Pixels.To2DArray(wb.PixelWidth); My conversion logic is as such: public static int[,] To2DArray(this int[] arr,int rowLength) { int[,] output = new int[rowLength, arr.Length / rowLength]; if (arr.Length % rowLength != 0) throw new IndexOutOfRangeException(); for (int i = 0; i < arr.Length; i++) { output[i % rowLength, i / rowLength] = arr[i]; } return output; } Now, when I do the checking, I get completely and utterly strange results: apparently all pixels are either at values of -1 or 0, and these values are completely independent of the original colours. Just for posterity: here's my checking code: private void Check(object sender, MouseButtonEventArgs e) { Point click = e.GetPosition(worldMap); ChangeNotification(intTest[(int)click.X,(int)click.Y].ToString()); } The result show absolutely no correlation to the path that the WriteableBitmap has rendered into it. The path has a fill of solid white. What the heck is going on? I've tried for hours with no luck. Please, this is the major problem stopping me from submitting my first WP7 app. Any guidance?

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• Aspect-Oriented Programming in OOP world - breaking rules ?

  - by Maksim Kondratyuk

  Hi 2 all! When I worked on asp.net mvc web site project, I investigated different approaches for validation. Some of them were DataAnotation validation and Validation Block. They use attributes for setting up rules for validation. Like this: [Required] public string Name {get;set;} I was confused how this approach combines with SRP (single responsibilty principle) from OOP world. Also I don't like any business logic in business objects, I prefer "poor business objects" model, but when I decorate my business objects with validation attributes for real requirements, they become ugly (Has a lot of attributes / with localization logic and so on). Idea with attributes realy simple, but in my opinion the validation decoration should be separated from object. I'm not sure is the approach to separate validation rules to xml files or to another objects, maybe it is a solution. Another bad side of AOP - problems with unit testin such code. When I decorated some controller actions with custom attributes for example to import/export TempData between actions or initialize some required services I can't to write proper unit test for testing this actions. Do you think that attributes don't break srp or you just disregard this and think that it's simplest , is not worst way ? P.S. I read some likes articles and discussions and I just want to put things in proper order. P.P.S. sorry for my "fluent" english :=)

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• Displaying tree path of record in SQL Server 2005

  - by jskiles1

  An example of my tree table is: ([id] is an identity) [id], [parent_id], [path] 1, NULL, 1 2, 1, 1-2 3, 1, 1-3 4, 3, 1-3-4 My goal is to query quickly for multiple rows of this table and view the full path of the node from its root, through its superiors, down to itself. The ultimate question is, should I generate this path on inserts and maintain it in its own column or generate this path on query to save disk space? I guess it depends if this table is write heavy or read heavy. I've been contemplating several approaches to using the "path" characteristic of this parent/child relationship and I just can't seem to settle on one. This "path" is simply for display purposes and serves absolutely no purpose other than that. Here is what I have done to implement this "path." AFTER INSERT TRIGGER - requires passing a NULL path to the insert and updating the path for the record at the inserted rows identity INSTEAD OF INSERT TRIGGER - does not require insert to have NULL path passed, but does require the trigger to insert with a NULL path and updating the path for the record at SCOPE_IDENTITY() STORED PROCEDURE - requiring all inserts into this table to be done through the stored procedure implementing the trigger logic VIEW - requires building the path in the view 1 and 2 seem annoying if massive amounts of data are entered at once. 3 seems annoying because all inserts must go through the procedure in order to have a valid path populated. 1, 2, and 3 require maintaining a path column on the table. 4 removes all the limitations of the above but require the view to perform the path logic and requires use of the view if a path is to be displayed. I have successfully implemented all of the above approaches and I'm mainly looking for some advice. Am I way off the mark here or are any of the above acceptable? Each has it's advantages and disadvantages.

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