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• Wondering where to begin

  - by Cat

  Hello all. After being interested for years and years (and years), I have finally decided to start learning how to create software and web applications. Base on recommendations, I have started with learning the basics of web design first (which I am almost done with) and then will move on to the meat of my process: learning the languages. Problem is, I don't know where to start :/ PHP, Ruby, Perl...and where would SQL, JavaScript and .NET fit into the mix? I am assuming they build on each other/play off of each other somewhat so following some sort of 'order' will make the process more logical and digestible. You're probably thinking, "Just go to school for computer engineering, duh!" But I already have a degree and don't plan on going back to school. I believe I have an adequate aptitude for this sort of thing, and although it will be challenging, with the support of the community I know I can do it on my own. Thank in advance everyone and I am very sorry for the length. I look forward to hearing what all you have to say. Warm Regards, Cat

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• How should child views of UIScrollView report their bounds for contentSize?

  - by Mike

  I'm looking more for advice on the correct design for a view. What I have is a UIScrollView that contains one or more custom Views I have created. My problem is, who reports to the scrollview what it's contentSize should be? I have the following: UIView +-UIScrollView +-CustomView 1 with dynamic height depending on data +-CustomView 2 with dynamic Height depending on data The UIViewController creates new instances of the custom views with data and then adds them as subviews to the UIScrollView. The problem I'm having is how to set the value of the scrollview's contentSize? Right now, I'm not doing that and the contents of the scrollview are clipped with no scrolling possible. Should the custom view call [parent setContentSize:] in its drawRect:? Should the UIViewController query the custom view after creation to get its bounds and then call setContentSize? Should I subclass the UIScrollView to override addSubView to query each subview's height? Is there something else I'm missing? I hope I explained that properly. I'm new to this and still getting a handle on things.

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• Architecture for new ASP.NET web application

  - by Anders Abel

  I'm maintaining an application which currently is just a web service (built with WCF) and a database backend. The web service is built in layers with a linq-to-sql data access part with core functionality in an own assembly and on top of that the web service assembly which contains the WCF code. The core assembly also handles all business logic rules (very few actually). The customer now wants a Web interface for the application instead of just accessing it through other applications which are consuming the web service. I'm quite lost on modern web application design, so I would like some advice on what architecture and frameworks to use for the web application. The web application will be using the same core assembly with business rules and the linq-to-sql data access layer as the web service. Some concepts I've thought about are: ASP.NET MVC Webforms AJAX controls - possibly leting the AJAX controls access the existing web service through JSON. Are there any more concepts I should look into? Which one is the best for a fresh project? The development tools are Visual Studio 2008 Team Edition for Developers targeting .NET 3.5. An upgrade to Visual Studio 2010 Premium (or maybe even Ultimate) is possible if it gives any benefits.

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• SSIS - Bulk Update at Database Field Level

  - by Adam

  Hello, Here's our mission: Receive files from clients. Each file contains anywhere from 1 to 1,000,000 records. Records are loaded to a staging area and business-rule validation is applied. Valid records are then pumped into an OLTP database in a batch fashion, with the following rules: If record does not exist (we have a key, so this isn't an issue), create it. If record exists, optionally update each database field. The decision is made based on one of 3 factors...I don't believe it's important what those factors are. Our main problem is finding an efficient method of optionally updating the data at a field level. This is applicable across ~12 different database tables, with anywhere from 10 to 150 fields in each table (original DB design leaves much to be desired, but it is what it is). Our first attempt has been to introduce a table that mirrors the staging environment (1 field in staging for each system field) and contains a masking flag. The value of the masking flag represents the 3 factors. We've then put an UPDATE similar to... UPDATE OLTPTable1 SET Field1 = CASE WHEN Mask.Field1 = 0 THEN Staging.Field1 WHEN Mask.Field1 = 1 THEN COALESCE( Staging.Field1 , OLTPTable1.Field1 ) WHEN Mask.Field1 = 2 THEN COALESCE( OLTPTable1.Field1 , Staging.Field1 ) ... As you can imagine, the performance is rather horrendous. Has anyone tackled a similar requirement? We're a MS shop using a Windows Service to launch SSIS packages that handle the data processing. Unfortunately, we're pretty much novices at this stuff.

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• C# - Naming a value combined "getter/setter" method (WebForms & Binding)

  - by tyndall

  Looking for some help on some names for a project I'm currently working on. I don't have a compsci degree so I don't know what to call this. I have a method called TryToGetSetValue(Direction direction, object value, object valueOnFail) Then there would be a Direction enum public enum Direction { ModelToForm, FormToModel } Background This is a legacy ASP.NET application. The models, database, and mainframe are designed poorly. I can't put in MVP or MVC patterns yet (too much work). ASP.NET code is a ridiculous mess (partial pages, single-page design, 5x the normal amount of jQuery, everything is a jQuery UI dialog). I'm just trying to put in a bridge so then I can do more refactoring over the next year. I have ~200 fields that need to be set on a GET and written back on a POST. I trying not to x2 these 200 fields and have 400 lines of code to support. What would you call my method? enum? Is there so other form of binding that would be easy to use instead? I'm not a fan of the DetailsView or FormView built-ins of ASP.NET WebForms.

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• How can I improve this search usability?

  - by Craig Whitley

  This is the first real programming attempt of mine, and theres some major flaws. It's a learning project, and I'm currently re-writing the entire thing as my php is is really messy. I really want to get an idea on how I can improve the actual usability and accesibility of the site at the same time though - so I know how to implement it correctly. The website is basically a comparison website for gameserver hosting. As I mentioned, its a learning project and I don't actually expect any revenue from it. At the moment theres only test data in it, so in the game input box select either 'Battlefied Bad Company 2' or 'Call of Duty 4: Modern Warfare' and ignore the actual search results. http://www.laglessfrag.com I wasn't really sure how to work the search functionality. Basically when you click a game in the drop down box, it sends an ajax request and finds all the locations available to that specific game in the database. After selecting the country theres another ajax to find all the citys available to the game in that country - which gives me the two unique identifiers I need to create the search results. One major and fundamental flaw is that without javascript enabled, the site ceases to function. I'll overcome that in the next re-write, but without the ajax functionality stopping the user 'going wrong' - how can I implement a search that requires two fields without creating extra steps in new pages after form submissions? I'm also no designer so my whole layout and css is a bit rubbish, but this was mainly a learning project as I'm interested in applications / programming rather than design. It's also slow as its on shared hosting, but if I can get it to work correctly then I'm not impartial to chucking a bit of money at it for faster hosting and maybe a bit of advertising and seeing where it goes (if anywhere!). Any info appreciated.

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• Exclude specific value from a Min/Max agregate funcion using ICriteria.

  - by sparks

  I have a schedule (Voyages) table like this: ID Arrival Departure OrderIndex 1 01/01/1753 02/10/2009 0 1 02/11/2009 02/15/2009 1 1 02/16/2009 02/19/2009 2 1 02/21/2009 01/01/1753 3 2 01/01/1753 03/01/2009 0 2 03/04/2009 03/07/2009 1 2 03/09/2009 01/01/1753 2 By design i save '01/01/1753' as a default value if the user doesn't fill a the field on the capture screen and for the very first Arrival and the very last Departure which are never provided. Im using Nhibernate and Criteria, and im wondering whats the best way to query this data if i want to know the First departure and last arrival for each voyage in the table. My first thought was a groupby (ID) and then do some Min and Max with the arrival and departure but the `'01/01/1753' VALUE is messing aronud. ... .SetProjection(Projections.ProjectionList() .Add(Projections.GroupProperty("ID"), "ID") .Add(Projections.Min("DepartureDate"), "DepartureDate") .Add(Projections.Max("ArrivalDate"), "ArrivalDate") ) ... So is there a way to skip this value in the Min function comparison (without losing the whole row of data), or there is a better way to do this, maybe utilizing the OrderIndex that always indicate the correct order of the elements, maybe ordering ASC taking the 1st and then Order DESC and taking the 1 st again, but im not quite sure how to do that with criteria syntax.

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• How to restrict text search to a certain subset of the database ?

  - by Nikhil Garg

  I have a large central database of around 1 million heavy records. In my app, for every user I would have a subset of rows from central table, which would be very small (probably 100 records each).When a particular user has logged in , I would want to search on this data set only. Example: Say I have a central database of all cars in the world. I have a user profile for General Motors(GM) , Ferrari etc. When GM is logged in I just want to search(a full text search and not fire a sql query) for those cars which are manufactured by GM. Also GM may launch/withdraw a model in which case central db would be updated & so would be rowset associated with GM. In case of acquisitions, db of certain profiles may change without launch/removal of new car. So central db wont change then , but rowsets may. Whats the best way to implement such a design ? These smaller row sets would need to be dynamic depending on user activities. We are on Rails 2.3.5 and use thinking_sphinx as the connector and Sphinx/MySQL for search and relational associations.

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• Injecting Dependencies into Domain Model classes with Nhibernate (ASP.NET MVC + IOC)

  - by Sunday Ironfoot

  I'm building an ASP.NET MVC application that uses a DDD (Domain Driven Design) approach with database access handled by NHibernate. I have domain model class (Administrator) that I want to inject a dependency into via an IOC Container such as Castle Windsor, something like this: public class Administrator { public virtual int Id { get; set; } //.. snip ..// public virtual string HashedPassword { get; protected set; } public void SetPassword(string plainTextPassword) { IHashingService hasher = IocContainer.Resolve<IHashingService>(); this.HashedPassword = hasher.Hash(plainTextPassword); } } I basically want to inject IHashingService for the SetPassword method without calling the IOC Container directly (because this is suppose to be an IOC Anti-pattern). But I'm not sure how to go about doing it. My Administrator object either gets instantiated via new Administrator(); or it gets loaded via NHibernate, so how would I inject the IHashingService into the Administrator class? On second thoughts, am I going about this the right way? I was hoping to avoid having my codebase littered with... currentAdmin.Password = HashUtils.Hash(password, Algorithm.Sha512); ...and instead get the domain model itself to take care of hashing and neatly encapsulate it away. I can envisage another developer accidently choosing the wrong algorithm and having some passwords as Sha512, and some as MD5, some with one salt, and some with a different salt etc. etc. Instead if developers are writing... currentAdmin.SetPassword(password); ...then that would hide those details away and take care of those problems listed above would it not?

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• Pass checkbox values with Jquery to PHP and display result in div

  - by user1343955

  I want to filter realtime results with jQuery (just like on this site http://shop.www.hi.nl/hi/mcsmambo.p?M5NextUrl=RSRCH). So when someones checks a checkbox the results should update realtime (in a div). Now I'm a newbie with jQuery and I've tried lots of examples but I can't get it to work. Here's my code, could anyone tell what I'm doing wrong? Thank you very much! HTML <div id="c_b"> Kleur:<br /> <input type="checkbox" name="kleur[1]" value="Blauw"> Blauw <br /> <input type="checkbox" name="kleur[2]" value="Wit"> Wit <br /> <input type="checkbox" name="kleur[3]" value="Zwart"> Zwart <br /> <br /> Operating System:<br /> <input type="checkbox" name="os[1]" value="Android"> Android <br /> <input type="checkbox" name="os[2]" value="Apple iOS"> Apple iOS <br /> </div> <div id="myResponse">Here should be the result</div> jQuery function updateTextArea() { var allVals = []; $('#c_b :checked').each(function() { allVals.push($(this).val()); }); var dataString = $(allVals).serialize(); $.ajax({ type:'POST', url:'/wp-content/themes/u-design/filteropties.php', data: dataString, success: function(data){ $('#myResponse').html(data); } }); } $(document).ready(function() { $('#c_b input').click(updateTextArea); updateTextArea(); }); PHP //Just to see if the var passing works echo var_export($_POST);

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• Creating content for rails-based applications

  - by Matthias Hryniszak

  Hi, I'm facing a problem of cleaning up my application in Ruby on Rails. What I have is a pretty standard 3-panel, header and footer layout where different parts of the screen contain different functionality. By that I mean for example that the header contains (among others) a select that allows one to select parts of the application and a context-dependent menu. The main content area contains obviously the most interactive stuff whereas side panels contain quick-links with stuff like shopping-cart preview, list of potentially attractive products for the customer, a selector to narrow down the list of options... I was wondering how do I go about simplifying the design. Right now I have the stuff that provides data for the "common" stuff (as opposed to direct content that's placed in the center) called from all the actions (with a filter) but that doesn't feel right for me. I've read that "components" are also not the way to go for obvious performance reasons. Is there something that's more like component-oriented (other frameworks do have that kind of stuff - Grails: <ui:include ../>, ASP.NET MVC: <% Html.RenderAction() %>)? Best regards, Matthias.

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• MySQL table data transformation -- how can I dis-aggreate MySQL time data?

  - by lighthouse65

  We are coding for a MySQL data warehousing application that stores descriptive data (User ID, Work ID, Machine ID, Start and End Time columns in the first table below) associated with time and production quantity data (Output and Time columns in the first table below) upon which aggregate (SUM, COUNT, AVG) functions are applied. We now wish to dis-aggregate time data for another type of analysis. Our current data table design: +---------+---------+------------+---------------------+---------------------+--------+------+ | User ID | Work ID | Machine ID | Event Start Time | Event End Time | Output | Time | +---------+---------+------------+---------------------+---------------------+--------+------+ | 080025 | ABC123 | M01 | 2008-01-24 16:19:15 | 2008-01-24 16:34:45 | 2120 | 930 | +---------+---------+------------+---------------------+---------------------+--------+------+ Reprocessing dis-aggregation that we would like to do would be to transform table content based on a granularity of minutes, rather than the current production event ("Event Start Time" and "Event End Time") granularity. The resulting reprocessing of existing table rows would look like: +---------+---------+------------+---------------------+--------+ | User ID | Work ID | Machine ID | Production Minute | Output | +---------+---------+------------+---------------------+--------+ | 080025 | ABC123 | M01 | 2010-01-24 16:19 | 133 | | 080025 | ABC123 | M01 | 2010-01-24 16:20 | 133 | | 080025 | ABC123 | M01 | 2010-01-24 16:21 | 133 | | 080025 | ABC123 | M01 | 2010-01-24 16:22 | 133 | | 080025 | ABC123 | M01 | 2010-01-24 16:23 | 133 | | 080025 | ABC123 | M01 | 2010-01-24 16:24 | 133 | | 080025 | ABC123 | M01 | 2010-01-24 16:25 | 133 | | 080025 | ABC123 | M01 | 2010-01-24 16:26 | 133 | | 080025 | ABC123 | M01 | 2010-01-24 16:27 | 133 | | 080025 | ABC123 | M01 | 2010-01-24 16:28 | 133 | | 080025 | ABC123 | M01 | 2010-01-24 16:29 | 133 | | 080025 | ABC123 | M01 | 2010-01-24 16:30 | 133 | | 080025 | ABC123 | M01 | 2010-01-24 16:31 | 133 | | 080025 | ABC123 | M01 | 2010-01-24 16:22 | 133 | | 080025 | ABC123 | M01 | 2010-01-24 16:33 | 133 | | 080025 | ABC123 | M01 | 2010-01-24 16:34 | 133 | +---------+---------+------------+---------------------+--------+ So the reprocessing would take an existing row of data created at the granularity of production event and modify the granularity to minutes, eliminating redundant (Event End Time, Time) columns while doing so. It assumes a constant rate of production and divides output by the difference in minutes plus one to populate the new table's Output column. I know this can be done in code...but can it be done entirely in a MySQL insert statement (or otherwise entirely in MySQL)? I am thinking of a INSERT ... INTO construction but keep getting stuck. An additional complexity is that there are hundreds of machines to include in the operation so there will be multiple rows (one for each machine) for each minute of the day. Any ideas would be much appreciated. Thanks.

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• File Storage for Web Applications: Filesystem vs DB vs NoSQL engines

  - by El Yobo

  I have a web application that stores a lot of user generated files. Currently these are all stored on the server filesystem, which has several downsides for me. When we move "folders" (as defined by our application) we also have to move the files on disk (although this is more due to strange design decisions on the part of the original developers than a requirement of storing things on the filesystem). It's hard to write tests for file system actions; I have a mock filesystem class that logs actions like move, delete etc, without performing them, which more or less does the job, but I don't have 100% confidence in the tests. I will be adding some other jobs which need to access the files from other service to perform additional tasks (e.g. indexing in Solr, generating thumbnails, movie format conversion), so I need to get at the files remotely. Doing this over network shares seems dodgy... Dealing with permissions on the filesystem as sometimes given us problems in the past, although now that we've moved to a pure Linux environment this should be less of an issue. What are the downsides of storing files as BLOBs in MySQL? I guess that it would massively increase the database size and reduce the effectiveness of caches, but are there other problems? Do the same problems exist with NoSQL systems like Cassandra? Does anyone have any other suggestions that might be appropriate?

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• Making Javascript and HTML5 games

  - by Jeff Meatball Yang

  A long time ago (Netscape 4-era), I wrote Javascript-based games: Pong, Minesweeper, and John Conway's Life among them. I'm getting back into it, and want to get my hands even dirtier. I have a few games in mind: Axis & Allies clone, with rugged maps and complex rules. Tetris clone, possibly with real-time player-vs-player or player-vs-computer mode Breakout clone, with a couple weapons and particle velocities In all of these, I have only a few objectives: Use JavaScript and HTML 5 - it should run on Chrome, Safari, or maybe an iPad. Start small and simple, then build-up features. Learn something new about game design and implementation. So my questions are: How would you implement these games? Do you have any technology recommendations? If you've written these games, what was the hardest part? N.B. I also want to start from first-principles - if you recommend a framework/library, I would appreciate some theory or implementation details behind it. These games are different enough that I should learn something new from each one.

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• How to identify the type of socket data?

  - by Nitesh Panchal

  Hello, May be i am not able to express my doubt properly in this question but still i will try. Basically i created a simple socket based chat program and everything works fine. But i think i have made many patches in it from the design point of view. I have used ObjectInputStream and ObjectOutputStreams in my program. The question i want to ask is how do i identify the different type of data that i send across the network? say if it is simple String type object i directly add to List<String> chatMessages. Now if want to ban certain users i created an another class :- public class User{ private String name; private String id; //getters and setters } This User class means no importance to me till now but i only created it to properly identify the action. Thus if i receive an instanceOf User i can be sure that some user is to be banned. That way i dont have to hardcode strings. I mean first i thought of sending something like "Banned User :" + userName and then i used to check if string startsWith "Banned User :" then i take some action :p. I've created a User class but it means no importance to me in my program. I want to know whether directly sending strings is good way or create a class for every action that is good. If i am not clear please let me know. If i have hundreds of action do i have to create hundreds of classes so i can check via instanceOf? Say now if i plan to create a BUZZ like facility that is available in yahoo messenger. Should i again create an another class named BUZZ? so it can be identified easily?

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• Should a new language compiler target the JVM?

  - by Pindatjuh

  I'm developing a new language. My initial target was to compile to native x86 for the Windows platform, but now I am in doubt. I've seen some new languages target the JVM (most notable Scala and Clojure). Ofcourse it's not possible to port every language easily to the JVM; to do so, it may lead to small changes to the language and it's design. So that's the reason behind this doubt, and thus this question: Is targetting the JVM a good idea, when creating a compiler for a new language? Or should I stick with x86? I have experience in generating JVM bytecode. Are there any workarounds to JVM's GC? The language has deterministic implicit memory management. How to produce JIT-compatible bytecode, such that it will get the highest speedup? Is it similar to compiling for IA-32, such as the 4-1-1 muops pattern on Pentium? I can imagine some advantages (please correct me if I'm wrong): JVM bytecode is easier than x86. Like x86 communicates with Windows, JVM communicates with the Java Foundation Classes. To provide I/O, Threading, GUI, etc. Implementing "lightweight"-threads.I've seen a very clever implementation of this at http://www.malhar.net/sriram/kilim/. Most advantages of the Java Runtime (portability, etc.) The disadvantages, as I imagined, are: Less freedom? On x86 it'll be more easy to create low-level constructs, while JVM has a higher level (more abstract) processor. Most disadvantages of the Java Runtime (no native dynamic typing, etc.)

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• .NET: How to know when serialization is completed?

  - by Ian Boyd

  When I construct my control (which inherits DataGrid), I add specific rows and columns. This works great at design time. Unfortunately, at runtime I add my rows and columns in the same constructor, but then the DataGrid is serialized (after the constructor runs) adding more rows and columns. After serialization is complete, I need to clear everything and re-initialize the rows and columns. Is there a protected method that I can override to know when the control is done serializing? Of course, I'd prefer to not have to do the work in the constructor, throw it away, and do it again after (potential) serialization. Is there a preferred event that is the equivalent of "set yourself up now", so that it is called once whether I'm serialized or not? The serialization i speak of comes from the InitializeComponent() method in the form's code-behind file. #region Windows Form Designer generated code /// <summary> /// Required method for Designer support - do not modify /// the contents of this method with the code editor. /// </summary> private void InitializeComponent() { ... } It would have been perfect if InitializeComponent was a virtual method defined by Control, then i could just override it and then perform my processing after i call base: protected override void InitializeComponent() { base.InitializeComponent(); InitializeMe(); } But it's not an ancestor method, it's declared only in the code-behind file. i notice that InitializeComponent calls SuspendLayout and ResumeLayout on various Controls. i thought it could override ResumeLayout, and perform my initialization then: public override void ResumeLayout() { base.ResumeLayout(); InitializeMe(); } But ResumeLayout is not virtual, so that's out. Anymore ideas? i can't be the first person to create a custom control.

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• Practical refactoring using unit tests

  - by awhite

  Having just read the first four chapters of Refactoring: Improving the Design of Existing Code, I embarked on my first refactoring and almost immediately came to a roadblock. It stems from the requirement that before you begin refactoring, you should put unit tests around the legacy code. That allows you to be sure your refactoring didn't change what the original code did (only how it did it). So my first question is this: how do I unit-test a method in legacy code? How can I put a unit test around a 500 line (if I'm lucky) method that doesn't do just one task? It seems to me that I would have to refactor my legacy code just to make it unit-testable. Does anyone have any experience refactoring using unit tests? And, if so, do you have any practical examples you can share with me? My second question is somewhat hard to explain. Here's an example: I want to refactor a legacy method that populates an object from a database record. Wouldn't I have to write a unit test that compares an object retrieved using the old method, with an object retrieved using my refactored method? Otherwise, how would I know that my refactored method produces the same results as the old method? If that is true, then how long do I leave the old deprecated method in the source code? Do I just whack it after I test a few different records? Or, do I need to keep it around for a while in case I encounter a bug in my refactored code? Lastly, since a couple people have asked...the legacy code was originally written in VB6 and then ported to VB.NET with minimal architecture changes.

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• jQuery: Stop browser scrolling on event update beyond the fold?

  - by neezer

  I have several links at the bottom of my page that update content at the top of my page (more than a viewport away). Here's the gist of what the update looks like: $('#private-photo div').fadeOut(function() { $(this).html('<%= escape_javascript(image_tag current_user.private_photo.image.url(:profile)) %>'); }).fadeIn(); Basically it's just fading out the old content and fading in the new content. My problem is that when this happens, the browser window automatically scrolls up just far enough so that the bottom of the updated content (#private-photo div) appears at the top of the browser viewport. I do not want this to happen. I want the content to be updated (still fading in and out), but without the browser viewport realigning its focus. I want to keep the animation because if the user has a big enough screen, or if they are using a link closer to the top of the page, I still want them to see the animation. Any ideas about how to prevent the browser from scrolling as described? If not, any suggestions for workarounds? FYI, I have this same problem in Safari 4, Chrome (for Mac), & Firefox 3.5. EDIT: Here's the link that calls the update action, which is itself inside a Colorbox: $('a.edit-photo').colorbox({ title: function() { return 'Edit Photo in ' + $(this).attr('rel'); }, overlayClose: false, onComplete: function() { $('#edit-photo-modal').submit(function(e) { $('#photo_submit').after('<span id="saving">Saving...</span>'); e.preventDefault(); $.post($(this).attr('action'), $(this).serialize(), function() { $('#edit-photo-modal #saving').text('Saved!'); }, "script"); }); } }); The lightbox opens, presents a form fetched through an AJAX request, then (on submit) triggers the update action mentioned above. I had these links outside of the Colorbox in an earlier design revision, and they exhibited the same problem, so I've ruled out Colorbox itself as a cause. If you need anymore info, let me know!

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• Are MEF's ComposableParts contracts instance-based?

  - by Dave

  I didn't really know how to phrase the title of my questions, so my apologies in advance. I read through parts of the MEF documentation to try to find the answer to my question, but couldn't find it. I'm using ImportMany to allow MEF to create multiple instances of a specific plugin. That plugin Imports several parts, and within calls to a specific instance, it wants these Imports to be singletons. However, what I don't want is for all instances of this plugin to use the same singleton. For example, let's say my application ImportManys Blender appliances. Every time I ask for one, I want a different Blender. However, each Blender Imports a ControlPanel. I want each Blender to have its own ControlPanel. To make things a little more interesting, each Blender can load BlendPrograms, which are also contained within their own assemblies, and MEF takes care of this loading. A BlendProgram might need to access the ControlPanel to get the speed, but I want to ensure that it is accessing the correct ControlPanel (i.e. the one that is associated with the Blender that is associated with the program!) This diagram might clear things up a little bit: As the note shows, I believe that the confusion could come from an inherently-poor design. The BlendProgram shouldn't touch the ControlPanel directly, and instead perhaps the BlendProgram should get the speed via the Blender, which will then delegate the request to its ControlPanel. If this is the case, then I assume the BlendProgram needs to have a reference to a specific Blender. In order to do this, is the right way to leverage MEF and use an ImportingConstructor for BlendProgram, i.e. [ImportingConstructor] public class BlendProgram : IBlendProgram { public BlendProgram( Blender blender) {} } And if this is the case, how do I know that MEF will use the intended Blender plugin?

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• Different Scala Actor Implementations Overview

  - by Stefan K.

  I'm trying to find the 'right' actor implementation for my thesis. I realized there is a bunch of them and it's a bit confusing to pick one. Personally I'm especially interested in remote actors, but I guess a complete overview would be helpful to many others. This is a pretty general question, so feel free to answer just for the implementation you know about. I know about the following Scala Actor implementations (SAI). Please add the missing ones. Scala 2.7 (difference to) Scala 2.8 Akka (http://www.akkasource.org/) Lift (http://liftweb.net/) Scalaz (http://code.google.com/p/scalaz/) What are the target use-cases for these SAIs (lightweight vs. "heavy" enterprise framework)? do they support remote actors? What shortcomings do remote actors have in the SAIs? How is their performace? How active is there community? How easy are they to get started? How good is the documentation? How easy are they to extend? How stable are they? Which projects are using them? What are their shortcomings? What are their design principles? Are they thread based or event based (receive/ react) or both? Nested receiveS hotswapping the Actor’s message loop

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• retrieving object information with Doctrine

  - by ajsie

  i want to fetch information from the database using objects. i really like this approach cause this is more OOP: $user = Doctrine_Core::getTable('User')->find(1); echo $user->Email['address']; echo $user->Phonenumbers[0]->phonenumber; rather than: $q = Doctrine_Query::create() ->from('User u') ->leftJoin('u.Email e') ->leftJoin('u.Phonenumbers p') ->where('u.id = ?', 1); $user = $q->fetchOne(); echo $user->Email['address']; echo $user->Phonenumbers[0]['phonenumber']; the problem is that the first one uses 3 queries (3 different tables), while the second one uses only 1 (and is therefore recommended technique). but i feel that it destroys the object oriented design. cause ORM is meant to give us an OOP approach so that we could focus on objects and not the relational database. but now they want us to go back to use SQL like pattern. there isn't a way to get information form multiple tables not using DQL? the above examples are taken from the documentation: doctrine

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• Forward declaration of derived inner class

  - by Loom

  I ran into problem implementing some variations of factory method. // from IFoo.h struct IFoo { struct IBar { virtual ~IBar() = 0; virtual void someMethod() = 0; }; virtual IBar *createBar() = 0; }; // from Foo.h struct Foo : IFoo { // implementation of Foo, Bar in Foo.cpp struct Bar : IBar { virtual ~Bar(); virtual void someMethod(); }; virtual Bar *createBar(); // implemented in Foo.cpp }; I'd like to place declaration of Foo::Bar in Foo.cpp. For now I cannot succeed: struct Foo : IFoo { //struct Bar; //1. error: invalid covariant return type // for ‘virtual Foo::Bar* //struct Bar : IBar; //2. error: expected ‘{’ before ‘;’ token virtual Bar *createBar(); // virtual IBar *createBar(); // Is not acceptable by-design }; Is there a trick to have just forward declaration of Boo in Foo.hpp and to have full declaration in Foo.cpp?

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• Is my method for avoiding dynamic_cast<> faster than dynamic_cast<> itself ?

  - by ereOn

  Hi, I was answering a question a few minutes ago and it raised to me another one: In one of my projects, I do some network message parsing. The messages are in the form of: [1 byte message type][2 bytes payload length][x bytes payload] The format and content of the payload are determined by the message type. I have a class hierarchy, based on a common class Message. To instanciate my messages, i have a static parsing method which gives back a Message* depending on the message type byte. Something like: Message* parse(const char* frame) { // This is sample code, in real life I obviously check that the buffer // is not NULL, and the size, and so on. switch(frame[0]) { case 0x01: return new FooMessage(); case 0x02: return new BarMessage(); } // Throw an exception here because the mesage type is unknown. } I sometimes need to access the methods of the subclasses. Since my network message handling must be fast, I decived to avoid dynamic_cast<> and I added a method to the base Message class that gives back the message type. Depending on this return value, I use a static_cast<> to the right child type instead. I did this mainly because I was told once that dynamic_cast<> was slow. However, I don't know exactly what it really does and how slow it is, thus, my method might be as just as slow (or slower) but far more complicated. What do you guys think of this design ? Is it common ? Is it really faster than using dynamic_cast<> ? Any detailed explanation of what happen under the hood when one use dynamic_cast<> is welcome !

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• How to debug PHP?

  - by NutMotion

  Anyone's been trying himself at object oriented programming ? Most probably every developer I guess:D I for one have never studied OO design patterns thoroughly, and trying to put it all together now does prove at times thrilling, and many times frustrating also. Even more so when trying to do it in : PHP! All-in-all, my boss asked me to add some Database persistence functions to her server, but most of all, she asked me to translate her already working procedural code into a working Object Oriented code. Here I am, still standing on my PHP OO project. I'm (already) fed up with this "file logging only" PHP capability. I believe there must be some (free or not too much expansive) PHP debugging utility ? I've heard about Zend Studio and PHPEd so far, which didn't quite do the trick for whatever reasons. WIRCW("Which I don't Remember Correctly Why" lol) What say yé? on debugging PHP ? Is there a tool that provides a good debug mode? what's more, don't forget I'm not speaking about the classical web Request/response model. Talking about a debugging facility which can enable you to trigger a web service (aka client request) and go into debug mode on the SOAP web service side. Thks for any input.

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