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• Law of Demeter in MVC regarding Controller-View communication

  - by Antonio MG

  The scenario: Having a Controller that controls a view composed of complex subviews. Each one of those subviews is a separated class in a separate file. For example, one of those subviews is called ButtonsView, and has a bunch of buttons. The Controller has to access those buttons. Would accessing those buttons like this: controllerMainView.buttonsView.firstButton.state(); be a violation of the LOD? On one hand, it could be yes because the controller is accessing the inner hierarchy of the view. On the other, a Controller should be aware of what happens inside the view and how is composed. Any thoughts?

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• Set modified date = created date or null on record creation?

  - by User

  I've been following the convention of adding created and modified columns to most of my database tables. I also have been leaving the modified column as null on record creation and only setting a value on actual modification. The other alternative is to set the modified date to be equal to created date on record creation. I've been doing it the former way but I recent ran into one con which is seriously making me think of switching. I needed to set a database cache dependency to find out if any existing data has been changed or new data added. Instead of being able to do the following: SELECT MAX(modified) FROM customer I have to do this: SELECT GREATEST(MAX(created), MAX(modified)) FROM customer The negative being that it's a more complicated query and slower. Another thing is in file systems I believe they usually use the second convention of setting modified date = created date on creation. What are the pros and cons of the different methods? That is, what are the issues to consider?

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• Bluetooth push application

  - by Paul Kassey

  I am considering the technical viability of software that I want to write. Is there a way that I can push data to a phone (iPhone or Andriod) via Bluetooth without pairing with it? I want to be able to walk into a room and have a computer push data to my phone when I get a certain distance from it, or push data to any phone automatically when it comes within a certain distance to a Bluetooth-ready device?

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• Brute force algorithm implemented for sudoku solver in C [closed]

  - by 0cool

  This is my code that I have written in C.. It could solve certain level of problems but not the harder one.. I could not locate the error in it, Can you please find that.. # include <stdio.h> # include "sudoku.h" extern int sudoku[size][size]; extern int Arr[size][size]; int i, j, n; int BruteForceAlgorithm (void) { int val; for (i=0; i<size; i++) { for (j=0; j<size; j++) { if (sudoku[i][j]==0) { for (n=1; n<nmax; n++) { val = check (i,j,n); if ( val == 1) { sudoku[i][j]=n; // output(); break; } else if ( val == 0 && n == nmax-1 ) get_back(); } } } } } int get_back (void) { int p,q; int flag=0; for ( p=i; p>=0; p-- ) { for (q=j; q>=0; q-- ) { flag=0; if ( Arr[p][q]==0 && !( p==i && q==j) ) { if ( sudoku[p][q]== nmax-1 ) sudoku[p][q]=0; else { n = sudoku[p][q]; sudoku[p][q]=0; i = p; j = q; flag = 1; break; } } } if ( flag == 1) break; } } Code description: Sudoku.h has definitions related to sudoku solver. 1. size = 9 nmax = 10 2. check(i,j,n) returns 1 if a number "n" can be placed at (i,j) or else "0". What does this code do ? The code starts iterating from sudoku[0][0] to the end... if it finds a empty cell ( we take cell having "0" ), it starts checking for n=1 to n=9 which can be put in that.. as soon as a number can be put in that which is checked by check() it assigns it and breaks from loop and starts finding another empty cell. In case for a particular cell if it doesn't find "n" which can be assigned to sudoku cell.. it goes back to the previous empty cell and start iterating from where it stopped and assigns the next value and continues, Here comes the function get_back(). it iterates back..

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• I want something ready to start with

  - by BDotA

  I am looking for something quick like a weblog in wordpress or blogspot maybe, that when I write a blog post I can put it there, for example if I write something about .NET or Java or Database,..some quick tutorial with some small code samples that visitors can use ... And I don't know anything about webdesign and I just want a ready-made thing to use for this purpose. What do you suggest? any samples of that that I can take a look?

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• Storing revisions of a document

  - by dev.e.loper

  This is a follow up question to my original question. I'm thinking of going with generating diffs and storing those diffs in the database 'History' table. I'm using diff-match-patch library to generate what is called a 'patch'. On every save, I compare previous and new version and generate this patch. The patch could be used to generate a document at specific point in time. My dilemma is how to store this data. Should I: a Insert a new database record for every patch? b. Store these patches in javascript array and store that array in history table. So there is only one db History record for document with an array of all the patches. Concerns with: a. Too many db records generated. Will be slow and CPU intensive to query. b. Only one record. If record is somehow corrupted/deleted. Entire revision history is gone. I'm looking for suggestions, concerns with either approach.

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• Combinatorial explosion of interfaces: How many is too many?

  - by mga

  I'm a relative newcomer to OOP, and I'm having a bit of trouble creating good designs when it comes to interfaces. Consider a class A with N public methods. There are a number of other classes, B, C, ..., each of which interacts with A in a different way, that is, accesses some subset (<= N) of A's methods. The maximum degree of encapsulation is achieved by implementing an interface of A for each other class, i.e. AInterfaceForB, AInterfaceForC, etc. However, if B, C, ... etc. also interact with A and with each other, then there will be a combinatorial explosion of interfaces (a maximum of n(n-1), to be precise), and the benefit of encapsulation becomes outweighed by a code-bloat. What is the best practice in this scenario? Is the whole idea of restricting access to a class's public functions in different ways for other different classes just silly altogether? One could imagine a language that explicitly allows for this sort of encapsulation (e.g. instead of declaring a function public, one could specify exactly which classes it is visible to); Since this is not a feature of C++, maybe it's misguided to try to do it through the back door with interaces?

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• How should UI layer pass user input to BL layer?

  - by BornToCode

  I'm building an n-tier application, I have UI, BL, DAL & Entities (built from POCO) projects. (All projects have a reference to the Entities). My question is - how should I pass user input from the UI to the BL, as a bunch of strings passed to the BL method and the BL will build the object from the parameters, or should I build the objects inside the UI submit_function and send objects as parameters? EDIT: I wrote n-tier application, but what I actually meant was just layers.

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• Can a table be both Fact and Dimension

  - by PatFromCanada

  Ok, I am a newbie and don't really think "dimensionally" yet, I have most of my initial schema roughed out but I keep flipping back and forth on one table. I have a Contract table and it has a quantity column (tonnes), and a net price column, which need to be summed up a bunch of different ways, and the contract has lots of foreign keys (producer, commodity, futures month etc.) and dates so it appears to be a fact table. Also the contract is never updated, if that makes a difference. However, we create cash tickets which we use to pay out part or all of the contract and they have a contract ID on them so then the contract looks like a dimension in the cash ticket's star schema. Is this a problem? Any ideas on the process to resolve this, because people don't seem to like the idea of joining two fact tables. Should I put producerId and commodityId on the cash ticket? It would seem really weird not to have a contractID on it.

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• Storing translation data as JSON column

  - by j0ntech

  We're deciding on how to store translations of some descriptions of database items. We could go the traditional way and keep a translations table (and a language table and an object_translation linking table) OR we thought it might be better to just have a Description column that contains JSON like the following: { "EN": "This is the translation in English", "EE" : "See on kirjeldus eesti keeles" } Are there any serious downsides as to why we shouldn't use this? (I haven't seen it being used anywhere else)

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• Efficient Algorithm for Recording gameplay's objects positions

  - by Scorch

  So, I have a game idea in mind, and for that I need to record the game around the player. I'me not talking about recording it as video, but rather recording the scene objects, and their positions within the game, and then render them, giving the player the ability to go back and forth, to stop time and move around. I've made a prototype with some data structures in C#, since this is going to be the programming language we'll be using in our game, but if we want the player to be able to go back just five minutes back with the data of just 100 NPC's, it takes almost 1GB of RAM. Right now, I'm just storing a Doubly linked list, each item with the object position. In the game, I'll need to store even more data in each node, so I need something even more ligher. Of course, this algorithm is zero optimized, but still, that is a lot. The alternatives would be create the NPC's that aren't really important to the game when the user is viewing the past, but I don't really like it very much for the sake of realism. I wonder if there is a better way to store this? Thanks in advance, Scorch

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• Draw "vision cone" / targetting element onto game world

  - by gkimsey

  I'm wanting to indicate various things using a "pie slice" sort of shape as below. Similar to vision cones in stealth game minimaps, or targetting indicators in RTS type games for frontal area attacks. Something generic enough to be used for both would be ideal. I need to be able to procedurally (and efficiently) change things like the slice width and length, color, transparency, position in the world, etc. For my particular situation, there's no concern with elevation, funky terrain, or really any third axis at all as far as this element is concerned. I have two first inclinations on how to accomplish this: 1) Manually generate the vertices for a main triangle, (possibly two, superimposed to get the border effect), a handful more to approximate the arc at the end, and roll it into a mesh. 2) Use some sort of 2D drawing library to create a circle and mask it off at the right angles, render to texture, and use that. For reference, I have some experience with Ogre3D, but I'm not attached to it as this is a mostly academic pursuit at the moment. Other technologies that might be better at accomplishing this are more than welcome. Finally, I'm kind of curious about how to do a "flashlight" or similar 3D effect that could produce the same result, but on all surfaces in the lit area.

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• Pending and Approval process

  - by zen

  So let's say I have a DB table with 8 columns, one is a unique auto-incrementing used as ID. So I have a page that pulls in the info for each row based on query string ID. I want to give my users the ability to propose changes. Kinda like a wiki setup. So I was thinking I should just have another duplicate table or maybe database altogether (without the auto-incrementing column and maybe with a date edited column) that keeps all proposed changes in queue and then when I approve them, the script can move the row from the proposed DB to the real DB. Does this sound good or is there a better process for this?

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• Many ui panels needs interaction with same object

  - by user877329

  I am developing a tool for simulating systems like the Gray-Scott model (That is systems where spatial distribution depends on time). The actual model is loaded from a DLL or shared object and the simulation is performed by a Simulation object. There are at least two situations when the simulation needs to be destroyed: The user loads a new model The user changes the size of the domain To make sure nothing goes wrong, the current Model, Simulation, and rendering Thread are all managed by an ApplicationState object. But the two cases above are initiated from two different UI objects. Is it then ok to distribute a reference to the ApplicationState object to all panels that need to access at least one method on the ApplicationState object? Another solution would be to use aggregation so that the panel from which the user chooses model knows the simulation parameter panel. Also, the ApplicationState class seems somewhat clumsy, so I would like to have something else

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• Dynamic Strategy Pattern [migrated]

  - by Karl Barker

  So I'm writing a web service architecture which includes FunctionProvider classes which do the actual processing of requests, and a main Endpoint class which receives and delegates requests to the proper FunctionProvider. I don't know exactly the FunctionProviders available at runtime, so I need to be able to 'register' (if that's the right word) them with my main Endpoint class, and query them to see if they match an incoming request. public class MyFunc implements FunctionProvider{ static { MyEndpoint.register(MyFunc); } public Boolean matchesRequest(Request req){...} public void processRequest(Request req){...} } public class MyEndpoint{ private static ArrayList<FunctionProvider> functions = new ArrayList<FunctionProvider>(); public void register(Class clz){ functions.add(clz); } public void doPost(Request request){ //find the FunctionProvider in functions //matching the request } } I've really not done much reflective Java like this (and the above is likely wrong, but hopefully demonstrates my intentions). What's the nicest way to implement this without getting hacky?

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• When creating a GUI wizard, should all pages/tabs be of the same size? [closed]

  - by Job

  I understand that some libraries would force me to, but my question is general. If I have a set of buttons at the bottom: Back, Next, Cancel?, (other?), then should their location ever change? If the answer is no, then what do I do about pages with little content? Do I stretch things? Place them in the lone upper left corner? According to Steve Krug, it does not make sense to add anything to GUI that does not need to be there. I understand that there are different approaches to wizards - some have tabs, others do not. Some tabs are lined horizontally at the top; others - vertically on the left. Some do not show pages/tabs, and are simply sequences of dialogs. This is probably a must when the wizard is "non-linear", e.g. some earlier choices can result in branching. Either way the problem is the same - sacrifice on the consistency of the "big picture" (outline of the page/tab + location of buttons), or the consistency of details (some tabs might be somewhat packed; others having very little content). A third choice, I suppose is putting extra effort in the content in order to make sure that organizing the content such that it is more or less evenly distributed from page to page. However, this can be difficult to do (say, when the very first tab contains only a choice of three things, and then branches off from there; there are probably other examples), and hard to maintain this balance if any of the content changes later. Can you recommend a good approach? A link to a relevant good blog post or a chapter of a book is also welcome. Let me know if you have questions.

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• How to fundamentally approach creating a 'financial planner' application?

  - by Anonymous -

  I want to create a financial planning application (for personal use), for which the overall functionality will be this: User (me..) can create different 'scenarios'. Each scenario is configured with different incomings/outgoings. Scenarios can be 'explored' in a calendar format with projections taking into account tax, interest (on both debt and savings) and so on and so forth. My problem lies in how to fundamentally approach the project. I've considered: When creating incomings/outgoings for a script to apply them to each day in a 'days' table of a database, acting as a method of caching. This means that if I wanted to look at January 14th, 2074 there aren't thousands of cycles of calculations to run through and the result can just be pulled. Do each calculation dynamically, but again, I'm finding it hard to visuallize how I would handle different tax allowances (I'm based in the UK by the way), payrises and 'changes' to my incomings/outgoings. I've sat on this for a couple of days and am struggling to come up with an elegant approach to my problem. There may well be software out there that does what I'm looking to do (in fact I'm sure it is) but I would like to develop this myself for learning purposes, to be able to add it to my personal life 'toolset' and to allow me to expand on it in the future. Many thanks to all who have any input on my dilemna.

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• Mobile Compatibility: traditional website look vs native application ?

  - by Siddiqui

  I have a question related to mobile compatible websites, I have seen two type of websites One in which they adopt traditional website look and adjust website according to mobile screen, if they have lot of information which can not be adjust according to screen then they expand the height of page, so that user can scroll the page to see more information... In the second approach they used native application look means use navigation-bar, tab-bar, tool-bar, scroll-view just like in native applications. Height and width of page adjust according to screen size, if they have more information then they use scroll-view etc... My question is: which approach is better then other, in which approach you feel more comfortable to use website.

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• Implenting ActiveRecord with inheritance?

  - by King

  I recently converted an old application that was using XML files as the data store to use SQL instead. To avoid a lot of changes I basically created ActiveRecord style classes that inherited from the original business objects. For example SomeClassRecord :SomeClass //ID Property //Save method I then used this new class in place of the other one, because of polymorphism I didn't need to change any methods that took SomeClass as a parameter. Would this be considered 'Bad'? What would be a better alternative?

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• Is there such a thing these days as programming in the small?

  - by WeNeedAnswers

  With all the programming languages that are out there, what exactly does it mean to program in the small and is it still possible, without the possibility of re-purposing to the large. The original article which mentions in the small was dated to 1975 and referred to scripting languages (as glue languages). Maybe I am missing the point, but any language that you can built components of code out of, I would regard to being able to handle "in the large". Is there a confusion on what Objects are and do they really figure as being mandatory to being able to handle "the large". Many have argued that this is the true meaning of "In the large" and that the concepts of objects are best fit for the job.

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• Is it a good idea to dynamically position and size controls on a form or statically set them?

  - by CrystalBlue

  I've worked mostly with interface building tools such as xCode's Interface Builder and Visual Studio's environment to place forms and position them on screens. But I'm finding that with my latest project, placing controls on the form through a graphical interface is not going to work. This more has to do with the number of custom controls I have to create that I can't visually see before hand. When I first tackled this, I began to position all of my controls relative to the last ones that I created. Doing this had its own pros and cons. On the one hand, this gave me the opportunity to set one number (a margin for example) and when I changed the margin, the controls all sized correctly to one another (such as shortening controls in the center while keeping controls next to the margin the same). But this started to become a spiders-web of code that I knew wouldn't go very far before getting dangerous. Change one number and everything re sizes, but remove one control and you've created many more errors and size problems for all the other controls. It became more surgery then small changes to controls and layout. Is there a good way or maybe a preferred way to determine when I should be using relative or absolute positioning in forms?

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• Best way to manage a changelog

  - by Gnial0id

  I'm currently developing a WinForm application. In order to inform the client about the improvements and corrections made during the last version, I would like to manage and display a changelog. I mostly found existing changelog on website (the term changelog is pretty used) or explanation on how to manage the release numbers, which I don't care. So, these are my questions: Is there a good practice in changelog management (using XML, pure text in the app, etc.) in a desktop application ? What is the best way to display it (external website, inside the winform application) ? Thanks.

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• Customer Reviews on Company Listings [closed]

  - by GSTAR

  I'm not sure if this is the right place but I am after some general advice on a feature I am looking to implement on my website. The website I have is a Wedding Directory. Here, companies can advertise in the form of a directory listing. This listing contains the company details - such as what they do and how you can contact them. There are three packages available - Basic package is free and Silver and Gold packages are charged for. Now in order to further enhance the directory, I want to enable customer reviews for each listing. This is basically whereby customers who have used a particular company's service can write a review (and rate out of 5) of their experience. The dilemma I face is that if customers are to be paying for their listings then surely they will expect to not have content on their listing that would tarnish their reputation (i.e. negative reviews). But at the same time I want to be impartial and help my site visitors to make informed choices on which companies to book when arranging their weddings. Of course I will exercise my ability to remove offensive or fake reviews but I do not want to be removing reviews just to satisfy my clients. Suppose a client pays me a premium fee to have their listing on my front page and at the top of the listings. Now suppose that client gets lost of negative reviews - the fact that they have increased visibility means that they will also get increased bad publicity. This in turn means they won't renew their package and will most likely request the listing to be taken down. So, how can I get the right balance here and keep everyone happy?

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• Would this data requirement suit a Document -Oriented database?

  - by codecowboy

  I have a requirement to allow users to fill in journal/diary entries per day. I want to provide a handful of known journal templates with x columns to fill in. An example might be a thought diary; a user has to record a thought in one column, describe the situation, rate how they felt etc. The other requirement is that a user should be able to create their own diary templates. They might have a need for a 10 column diary entry per day and might need to rate some aspect out of 50 instead of 10. In an RDBMS, I can see this getting quite complicated. I could have individual tables for my known templates as the fields will be fixed. But for custom diary templates I imagine I would would need a table storing custom_field_types (the diary columns), a table storing entries referencing their field types (custom_entries) and then a third custom_diary table which would store rows matching custom_entries to diaries. Leaving performance / scaling aside, would it be any simpler or make more sense to use a document oriented database like MongoDB to store this data? This is for a web application which might later need an API for mobile devices.

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• Using Copyrighted Images

  - by TMP

  I was thinking about developing a sidescrolling platformer very similar to an old Mario and Luigi game for NES. To start out I was thinking about taking the images from a site like this: http://www.mariouniverse.com/sprites/nes/smb3 Which clearly states a copyright. I was wondering how far I am allowed to take these images. I figure I'm probably allowed to use it for personal development, but what if I publish the game as an exe file and send it to some friends? I figured a definite no-no would be selling the game with the copyrighted images included. A secondary question would be whether or not I would be allowed to modify them slightly and then call them my own.

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