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  • Efficiently separating Read/Compute/Write steps for concurrent processing of entities in Entity/Component systems

    - by TravisG
    Setup I have an entity-component architecture where Entities can have a set of attributes (which are pure data with no behavior) and there exist systems that run the entity logic which act on that data. Essentially, in somewhat pseudo-code: Entity { id; map<id_type, Attribute> attributes; } System { update(); vector<Entity> entities; } A system that just moves along all entities at a constant rate might be MovementSystem extends System { update() { for each entity in entities position = entity.attributes["position"]; position += vec3(1,1,1); } } Essentially, I'm trying to parallelise update() as efficiently as possible. This can be done by running entire systems in parallel, or by giving each update() of one system a couple of components so different threads can execute the update of the same system, but for a different subset of entities registered with that system. Problem In reality, these systems sometimes require that entities interact(/read/write data from/to) each other, sometimes within the same system (e.g. an AI system that reads state from other entities surrounding the current processed entity), but sometimes between different systems that depend on each other (i.e. a movement system that requires data from a system that processes user input). Now, when trying to parallelize the update phases of entity/component systems, the phases in which data (components/attributes) from Entities are read and used to compute something, and the phase where the modified data is written back to entities need to be separated in order to avoid data races. Otherwise the only way (not taking into account just "critical section"ing everything) to avoid them is to serialize parts of the update process that depend on other parts. This seems ugly. To me it would seem more elegant to be able to (ideally) have all processing running in parallel, where a system may read data from all entities as it wishes, but doesn't write modifications to that data back until some later point. The fact that this is even possible is based on the assumption that modification write-backs are usually very small in complexity, and don't require much performance, whereas computations are very expensive (relatively). So the overhead added by a delayed-write phase might be evened out by more efficient updating of entities (by having threads work more % of the time instead of waiting). A concrete example of this might be a system that updates physics. The system needs to both read and write a lot of data to and from entities. Optimally, there would be a system in place where all available threads update a subset of all entities registered with the physics system. In the case of the physics system this isn't trivially possible because of race conditions. So without a workaround, we would have to find other systems to run in parallel (which don't modify the same data as the physics system), other wise the remaining threads are waiting and wasting time. However, that has disadvantages Practically, the L3 cache is pretty much always better utilized when updating a large system with multiple threads, as opposed to multiple systems at once, which all act on different sets of data. Finding and assembling other systems to run in parallel can be extremely time consuming to design well enough to optimize performance. Sometimes, it might even not be possible at all because a system just depends on data that is touched by all other systems. Solution? In my thinking, a possible solution would be a system where reading/updating and writing of data is separated, so that in one expensive phase, systems only read data and compute what they need to compute, and then in a separate, performance-wise cheap, write phase, attributes of entities that needed to be modified are finally written back to the entities. The Question How might such a system be implemented to achieve optimal performance, as well as making programmer life easier? What are the implementation details of such a system and what might have to be changed in the existing EC-architecture to accommodate this solution?

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  • What Color is your Jetpack ?

    - by JoshReuben
    I’m a programmer, Im approaching 40, and I’m fairly decent at my job – I’ll keep doing what I’m doing for as long as they let me!   So what are your career options if you know how to code? A Programmer could be ..   An Algorithm developer Pros Interesting High barriers of entry, potential for startup competitive factor Cons Do you have the skill, qualifications? What are working conditions n this mystery niche ? micro-focus An Academic Pros Low pressure Job security – or is this an illusion ? Cons Low Pay Need a PhD A Software Architect Pros: strategic, rather than tactical Setting technology platform and high level vision You say how it should work, others have to figure out why its not working the way its supposed to ! broad view – you are paid to learn (how do you con people into paying for you to learn ??) Cons: Glorified developer – more often than not! competitive – everyone wants to do it ! loose touch with underlying tech in tough times, first guy to get the axe ! A Software Engineer Pros: interesting, always more to learn fun I can do it Fallback Cons: Nothing new under the sun – been there, done that Dealing with poor requirements, deadlines, other peoples code, overtime C#, XAML, Web - Low barriers of entry –> à race to the bottom A Team leader Pros: Setting code standards and proposing technology choices Cons: Glorified developer – more often than not! Inspecting other peoples code and debugging the problems they cannot fix Dealing with mugbies and prima donas Responsible for QA of others A Project Manager Pros No need for debugging other peoples code Cons Low barrier of entry High pressure Responsible for QA of others Loosing touch with technology A lot of bullshit meetings Have to be an asshole A Product Manager Pros No need for debugging other peoples code Learning new skillset of sales and marketing Cons Travel (I'm a family man) May need to know the bs details of an uninteresting product things I want to work with: AI, algorithms, Numerical Computing, Mathematica, C++ AMP – unfortunately, the work here is few & far between. VS & TFS Extensibility, DSLs (Workflow , Lightswitch), Code Generation – one day, code will write code ! Unity3D, WebGL – fun, fun, fun ! Modern Web – Knockout, SignalR, MVC, Node.Js ??? (tentative – I'll wait until things stabilize as this area is undergoing a pre-Cambrian explosion) Things I don’t want to work with: (but will if I'm asked to !) C# – same old, same old – not learning anything new here Old code – blech ! Environment with code & fix mentality , ad hoc requirements, excessive overtime Pc support, System administration – even after 20 years, people still ask you to do this sometimes ! debugging – my skills are just not there yet Oracle Old tech: VB 6, XSLT, WinForms, Net 3.51 or less Old style Web dev Information Systems: ASP.NET webforms, Reporting services / crystal reports, SQL Server CRUD with manual data layer, XAML MVVM – variations of the same concept, ad nauseaum. Low barriers of entry –> race to the bottom.  Metro – an elegant API coupled to a horrendous UX – I'll wait for market penetration viability before investing further in this.   Conclusion So if you are in a slump, take heart: Programming is a great career choice compared to every other job !

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  • Antenna Aligner Part 4: Role'ing in the deep

    - by Chris George
    Since last time I've been trying to sort out the general workflow of the app. It's fundamentally not hard, there is a list of transmitters, you select a transmitter and it shows the compass view. Having done quite a bit of ajax/asp.net/html in the past, I immediately started off by creating two divs within my 'page', one for the list, one for the compass. Then using the onClick event in the list, this will switch the display attribute on the divs. This seemed to work, but did lead to some dodgy transitional redrawing artefacts which I was not happy with. So after some Googling I realised I was doing it all wrong! JQuery mobile has the concept of giving an object in html a data-role. By giving a div the attribute data-role="page" it is then treated as a separate page on the mobile device. Within the code, this is referenced like a html anchor in the form #mypage. Using this system, page transitions such as fade or slide are automatically applied which adds to the whole authenticity of the app! Here is a simple example: . <a href="#'compasspage">compass</a> . <div data-role="page" id="compasspage" data-add-back-btn="true"> But I don't want just a static link, I want to dynamically create my list, and get each list elements to switch to the compass page with the right information. So here is the jquery that I used to dynamically inject new <li> rows into the <ul> block. $('ul').append($('<li/>', {    //here appendin `<li>`     'data-role': "list-divider" }).append($('<a/>', {    //here appending `<a>` into `<li>`     'href': '#compasspage',     'data-transition': 'none',     'onclick': 'selectTx(' + i + ')',     'html': buttonHtml }))); $('ul').listview('refresh'); This is called within a for loop so the first 5 appropriate transmitters are used. There are several things of interest to note here. Firstly, I could not find a more elegant way to tell the target page which transmitter I've clicked on, so I have used the onclick event as well as the href attribute. The onclick event fires 'selectTx' which simply sets a global member variable to the specific index number I've clicked on. Yes it's not nice, but it works. Secondly, the data-transition attribute is set to 'none'. I wanted the transition between the pages to be a whooshy slidey effect. However this worked going to the compass page, but returning to the list page gave some undesirable visual artefacts (flickering, redrawing etc.). So I decided to remove the transitions all together, which was a shame. Thirdly, rather than embedding loads of html into the append command, I removed this out into a variable 'buttonHtml'. Doing this really tidied up my code. Until next time!

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  • Viewport / Camera Calculation in 2D Game

    - by Dave
    we have a 2D game with some sprites and tiles and some kind of camera/viewport, that "moves" around the scene. so far so good, if we wouldn't had some special behaviour for your camera/viewport translation. normally you could stick the camera to your player figure and center it, resulting in a very cheap, undergraduate, translation equation, like : vec_translation -/+= speed (depending in what keys are pressed. WASD as default.) buuuuuuuuuut, we want our player figure be able to actually reach the bounds, when the viewport/camera has reached a maximum translation. we came up with the following solution (only keys a and d are the shown here, the rest is just adaption of calculation or maybe YOUR super-cool and elegant solution :) ): if(keys[A]) { playerX -= speed; if(playerScreenX <= width / 2 && tx < 0) { playerScreenX = width / 2; tx += speed; } else if(playerScreenX <= width / 2 && (tx) >= 0) { playerScreenX -= speed; tx = 0; if(playerScreenX < 0) playerScreenX = 0; } else if(playerScreenX >= width / 2 && (tx) < 0) { playerScreenX -= speed; } } if(keys[D]) { playerX += speed; if(playerScreenX >= width / 2 && (-tx + width) < sceneWidth) { playerScreenX = width / 2; tx -= speed; } if(playerScreenX >= width / 2 && (-tx + width) >= sceneWidth) { playerScreenX += speed; tx = -(sceneWidth - width); if(playerScreenX >= width - player.width) playerScreenX = width - player.width; } if(playerScreenX <= width / 2 && (-tx + width) < sceneWidth) { playerScreenX += speed; } } i think the code is rather self explaining: keys is a flag container for currently active keys, playerX/-Y is the position of the player according to world origin, tx/ty are the translation components vital to background / npc / item offset calculation, playerOnScreenX/-Y is the actual position of the player figure (sprite) on screen and width/height are the dimensions of the camera/viewport. this all looks quite nice and works well, but there is a very small and nasty calculation error, which in turn sums up to some visible effect. let's consider following piece of code: if(playerScreenX <= width / 2 && tx < 0) { playerScreenX = width / 2; tx += speed; } it can be translated into plain english as : if the x position of your player figure on screen is less or equal the half of your display / camera / viewport size AND there is enough space left LEFT of your viewport/camera then set players x position on screen to width half, increase translation (because we subtract the translation from something we want to move). easy, right?! doing this will create a small delta between playerX and playerScreenX. after so much talking, my question appears now here at the bottom of this document: how do I stick the calculation of my player-on-screen to the actual position of the player AND having a viewport that is not always centered aroung the players figure? here is a small test-case in processing: http://pastebin.com/bFaTauaa thank you for reading until now and thank you in advance for probably answering my question.

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  • Oracle ZS3 Contest for Partners: Share an unforgettable experience at the Teatro Alla Scala in Milan

    - by Claudia Caramelli-Oracle
    12.00 Dear valued Partner, We are pleased to launch a partner contest exclusive to our partners dedicated to promoting and selling Oracle Systems! You are essential to the success of Oracle and we want to recognize your contribution and effort in driving Oracle Storage to the market. To show our appreciation we are delighted to announce a contest, giving the winners the opportunity to attend a roundtable chaired by Senior Oracle Executives and spend an unforgettable evening at the magnificent Teatro Alla Scala in Milan, followed by a stay at the Grand Hotel et de Milan, courtesy of Oracle. Recognition will be given to 12 partner companies (10 VARs & 2 VADs) who will be recognized for their ZFS storage booking achievement in the broad market between June 1st and July 18th 2014. Criteria of Eligibility A minimum deal value of $30k is required for qualification Partners who are wholly or partially owned by a public sector organization are not eligible for participation  Winners The winning VARs will be: The highest ZS3 or ZBA bookings achievers by COB on July 18th, 2014 in each Oracle EMEA region (1) The highest Oracle on Oracle (2) ZS3 or ZBA bookings achievers by COB on July 18th, 2014 in each Oracle EMEA region The winning VADs (3) will be: The highest ZS3 or ZBA bookings achiever by COB on July 18th 2014 in EMEA The highest Oracle on Oracle (2) ZS3 or ZBA bookings achiever by COB on July 18th 2014 in EMEA  The Prize Winners will be invited to participate to a roundtable chaired by Oracle on Monday September 8th 2014 in Milan and to be guests of Oracle in the evening of September 8th, 2014 at the Teatro Alla Scala. The evening will comprise of a private tour of the Scala museum, cocktail reception at the elegant museum rooms and attending the performance by the renowned Soprano, Maria Agresta. Our guests will then retire for the evening to the Grand Hotel et de Milan, courtesy of Oracle. Oracle shall be the final arbiter in selecting the winners and all winners will be notified via their Oracle account manager.Full details about the contest, expenses covered by Oracle and timetable of events can be found on the Oracle EMEA Hardware (Servers & Storage) Partner Community workspace (FY15 Q1 ZFS Partner Contest). Remember: access to the community workspace requires membership. If you are not a member please register here. Good Luck!! For more information, please contact Sasan Moaveni. (1) Two VAR winners for each EMEA region – Eastern Europe & CIS, Middle East & Africa, South Europe, North Europe, UK/Ireland & Israel - as per the criteria outlined above (2) Oracle on Oracle, in this instance, means ZS3 or ZBA storage attached to DB or DB options, Engineered Systems or Sparc servers sold to the same customer by the same partner within the contest timelines.(3) Two VAD winners, one for each of the criteria outlined above, will be selected from across EMEA. Normal 0 14 false false false IT X-NONE X-NONE MicrosoftInternetExplorer4 /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0cm 5.4pt 0cm 5.4pt; mso-para-margin-top:0cm; mso-para-margin-right:0cm; mso-para-margin-bottom:10.0pt; mso-para-margin-left:0cm; line-height:115%; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:"Times New Roman"; mso-bidi-theme-font:minor-bidi; mso-fareast-language:EN-US;}

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  • Using Recursive SQL and XML trick to PIVOT(OK, concat) a "Document Folder Structure Relationship" table, works like MySQL GROUP_CONCAT

    - by Kevin Shyr
    I'm in the process of building out a Data Warehouse and encountered this issue along the way.In the environment, there is a table that stores all the folders with the individual level.  For example, if a document is created here:{App Path}\Level 1\Level 2\Level 3\{document}, then the DocumentFolder table would look like this:IDID_ParentFolderName1NULLLevel 121Level 232Level 3To my understanding, the table was built so that:Each proposal can have multiple documents stored at various locationsDifferent users working on the proposal will have different access level to the folder; if one user is assigned access to a folder level, she/he can see all the sub folders and their content.Now we understand from an application point of view why this table was built this way.  But you can quickly see the pain this causes the report writer to show a document link on the report.  I wasn't surprised to find the report query had 5 self outer joins, which is at the mercy of nobody creating a document that is buried 6 levels deep, and not to mention the degradation in performance.With the help of 2 posts (at the end of this post), I was able to come up with this solution:Use recursive SQL to build out the folder pathUse SQL XML trick to concat the strings.Code (a reminder, I built this code in a stored procedure.  If you copy the syntax into a simple query window and execute, you'll get an incorrect syntax error) Normal 0 false false false EN-US X-NONE X-NONE MicrosoftInternetExplorer4 /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin-top:0in; mso-para-margin-right:0in; mso-para-margin-bottom:10.0pt; mso-para-margin-left:0in; line-height:115%; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-fareast-font-family:"Times New Roman"; mso-fareast-theme-font:minor-fareast; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:"Times New Roman"; mso-bidi-theme-font:minor-bidi;} -- Get all folders and group them by the original DocumentFolderID in PTSDocument table;WITH DocFoldersByDocFolderID(PTSDocumentFolderID_Original, PTSDocumentFolderID_Parent, sDocumentFolder, nLevel)AS (-- first member      SELECT 'PTSDocumentFolderID_Original' = d1.PTSDocumentFolderID            , PTSDocumentFolderID_Parent            , 'sDocumentFolder' = sName            , 'nLevel' = CONVERT(INT, 1000000)      FROM (SELECT DISTINCT PTSDocumentFolderID                  FROM dbo.PTSDocument_DY WITH(READPAST)            ) AS d1            INNER JOIN dbo.PTSDocumentFolder_DY AS df1 WITH(READPAST)                  ON d1.PTSDocumentFolderID = df1.PTSDocumentFolderID      UNION ALL      -- recursive      SELECT ddf1.PTSDocumentFolderID_Original            , df1.PTSDocumentFolderID_Parent            , 'sDocumentFolder' = df1.sName            , 'nLevel' = ddf1.nLevel - 1      FROM dbo.PTSDocumentFolder_DY AS df1 WITH(READPAST)            INNER JOIN DocFoldersByDocFolderID AS ddf1                  ON df1.PTSDocumentFolderID = ddf1.PTSDocumentFolderID_Parent)-- Flatten out folder path, DocFolderSingleByDocFolderID(PTSDocumentFolderID_Original, sDocumentFolder)AS (SELECT dfbdf.PTSDocumentFolderID_Original            , 'sDocumentFolder' = STUFF((SELECT '\' + sDocumentFolder                                         FROM DocFoldersByDocFolderID                                         WHERE (PTSDocumentFolderID_Original = dfbdf.PTSDocumentFolderID_Original)                                         ORDER BY PTSDocumentFolderID_Original, nLevel                                         FOR XML PATH ('')),1,1,'')      FROM DocFoldersByDocFolderID AS dfbdf      GROUP BY dfbdf.PTSDocumentFolderID_Original) And voila, I use the second CTE to join back to my original query (which is now a CTE for Source as we can now use MERGE to do INSERT and UPDATE at the same time).Each part of this solution would not solve the problem by itself because:If I don't use recursion, I cannot build out the path properly.  If I use the XML trick only, then I don't have the originating folder ID info that I need to link to the document.If I don't use the XML trick, then I don't have one row per document to show in the report.I could conceivably do this in the report function, but I'd rather not deal with the beginning or ending backslash and how to attach the document name.PIVOT doesn't do strings and UNPIVOT runs into the same problem as the above.I'm excited that each version of SQL server provides us new tools to solve old problems and/or enables us to solve problems in a more elegant wayThe 2 posts that helped me along:Recursive Queries Using Common Table ExpressionHow to use GROUP BY to concatenate strings in SQL server?

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  • Writing a method to 'transform' an immutable object: how should I approach this?

    - by Prog
    (While this question has to do with a concrete coding dilemma, it's mostly about what's the best way to design a function.) I'm writing a method that should take two Color objects, and gradually transform the first Color into the second one, creating an animation. The method will be in a utility class. My problem is that Color is an immutable object. That means that I can't do color.setRGB or color.setBlue inside a loop in the method. What I can do, is instantiate a new Color and return it from the method. But then I won't be able to gradually change the color. So I thought of three possible solutions: 1- The client code includes the method call inside a loop. For example: int duration = 1500; // duration of the animation in milliseconds int steps = 20; // how many 'cycles' the animation will take for(int i=0; i<steps; i++) color = transformColor(color, targetColor, duration, steps); And the method would look like this: Color transformColor(Color original, Color target, int duration, int steps){ int redDiff = target.getRed() - original.getRed(); int redAddition = redDiff / steps; int newRed = original.getRed() + redAddition; // same for green and blue .. Thread.sleep(duration / STEPS); // exception handling omitted return new Color(newRed, newGreen, newBlue); } The disadvantage of this approach is that the client code has to "do part of the method's job" and include a for loop. The method doesn't do it's work entirely on it's own, which I don't like. 2- Make a mutable Color subclass with methods such as setRed, and pass objects of this class into transformColor. Then it could look something like this: void transformColor(MutableColor original, Color target, int duration){ final int STEPS = 20; int redDiff = target.getRed() - original.getRed(); int redAddition = redDiff / steps; int newRed = original.getRed() + redAddition; // same for green and blue .. for(int i=0; i<STEPS; i++){ original.setRed(original.getRed() + redAddition); // same for green and blue .. Thread.sleep(duration / STEPS); // exception handling omitted } } Then the calling code would usually look something like this: // The method will usually transform colors of JComponents JComponent someComponent = ... ; // setting the Color in JComponent to be a MutableColor Color mutableColor = new MutableColor(someComponent.getForeground()); someComponent.setForeground(mutableColor); // later, transforming the Color in the JComponent transformColor((MutableColor)someComponent.getForeground(), new Color(200,100,150), 2000); The disadvantage is - the need to create a new class MutableColor, and also the need to do casting. 3- Pass into the method the actual mutable object that holds the color. Then the method could do object.setColor or similar every iteration of the loop. Two disadvantages: A- Not so elegant. Passing in the object that holds the color just to transform the color feels unnatural. B- While most of the time this method will be used to transform colors inside JComponent objects, other kinds of objects may have colors too. So the method would need to be overloaded to receive other types, or receive Objects and have instanceof checks inside.. Not optimal. Right now I think I like solution #2 the most, than solution #1 and solution #3 the least. However I'd like to hear your opinions and suggestions regarding this.

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  • What good technology podcasts are out there?

    - by Michael Stum
    Yes, Podcasts, those nice little Audiobooks I can listen to on the way to work. With the current amount of Podcasts, it's like searching a needle in a haystack, except that the haystack happens to be the Internet and is filled with too many of these "Hot new Gadgets" stuff :( Now, even though I am mainly a .NET developer nowadays, maybe anyone knows some good Podcasts from people regarding the whole software lifecycle? Unit Testing, Continous Integration, Documentation, Deployment... So - what are you guys and gals listening to? Please note that the categorizations are somewhat subjective and may not be 100% accurate as many podcasts cover several areas. Categorization is made against what is considered the "main" area. General Software Engineering / Productivity Stack Overflow TekPub (Requires Paid Subscription) SE Radio 43 Folders Perspectives Dr. Dobb's (now a video feed) The Pragmatic Podcast (Inactive) IT Matters Agile Toolkit Podcast The Stack Trace (Inactive) Parleys Techzing The Startup Success Podcast Berkeley CS class lectures FOSS Weekly .NET / Visual Studio / Microsoft Herding Code Hanselminutes .NET Rocks! Deep Fried Bytes Alt.Net Podcast Polymorphic Podcast Sparkling Client (The Silverlight Podcast) dnrTV! Spaghetti Code ASP.NET Podcast Channel 9 Radio TFS PowerScripting Podcast The Thirsty Developer Elegant Code ConnectedShow Crafty Coders Coding QA jQuery yayQuery The official jQuery podcast Java / Groovy The Java Posse Grails Podcast Java Technology Insider Ruby / Rails Railscasts Rails Envy The Ruby on Rails Podcast Rubiverse Web Design / JavaScript / Ajax WebDevRadio Boagworld The Rissington podcast Ajaxian YUI Theater Unix / Linux / Mac / iPhone Mac Developer Network Hacker Public Radio Linux Outlaws Mac OS Ken LugRadio Linux radio show (Inactive) The Linux Action Show! Linux Kernel Mailing List (LKML) Summary Podcast Stanford's iPhone programming class SysAdmin, Security or Infrastructure RunAs Radio Security Now! Crypto-Gram Security Podcast Hak5 VMWare VMTN Windows Weekly PaulDotCom Security The Register - Semi-Coherent Computing FeatherCast General Tech / Business Tekzilla This Week in Tech The Guardian Tech Weekly PCMag Radio Podcast Entrepreneurship Corner Manager Tools Other / Misc. / Podcast Networks IT Conversations Retrobits Podcast No Agenda Netcast Cranky Geeks The Command Line Freelance Radio IBM developerWorks The Register - Open Season Drunk and Retired Technometria Sod This Radio4Nerds Hacker Medley

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  • UIImagePickerController in landscape on iPhone OS >= 3.2

    - by Mike
    Here is the problem. I have to open the UIImagePickerController in landscape. At this phase I am doing the app for iPhone but it will be soon adjusted for iPad. The classical way to force the UIImagePickerController to open in landscape would be to use this solution. But this solution has a problem, specially for iPad, that is the line, [[UIDevice currentDevice] setOrientation:UIInterfaceOrientationLandscapeRight]; because Apple rejects an application for doing that, as they don't want you to set an orientation, because if the user is holding the iPad on landscapeLeft the controller will appear upside down. Apple want you to use your paranormal powers and open the controller the right way for the user. The only problem is this: My controller is to appear when the application starts At this time, the orientation information is not yet available, because it takes a while for the device to discover its orientation; I've tried to get around this using the accelerometer to discover the orientation, but the accelerometer data is not yet available too when the app starts. I could make a routine to delay the application until the orientation is available, showing a black screen to the user in the mean time, or a beach ball, but I wonder if there's a more elegant way to do that! thanks.

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  • Java RegEx API "Look-behind group does not have an obvious maximum length near index ..."

    - by Foo Inc
    Hello, I'm on to some SQL where clause parsing and designed a working RegEx to find a column outside string literals using "Rad Software Regular Expression Desginer" which is using the .NET API. To make sure the designed RegEx works with Java too, I tested it by using the API of course (1.5 and 1.6). But guess what, it won't work. I got the message "Look-behind group does not have an obvious maximum length near index 28". The string that I'm trying to get parsed is Column_1='test''the''stuff''all''day''long' AND Column_2='000' AND TheVeryColumnIWantToFind = 'Column_1=''test''''the''''stuff''''all''''day''''long'' AND Column_2=''000'' AND TheVeryColumnIWantToFind = '' TheVeryColumnIWantToFind = '' AND (Column_3 is null or Column_3 = ''Not interesting'') AND ''1'' = ''1''' AND (Column_3 is null or Column_3 = 'Still not interesting') AND '1' = '1' As you may have guessed, I tried to create some kind of worst case to ensure the RegEx won't fail on more complicated SQL where clauses. The RegEx itself looks like this (?i:(?<!=\s*'(?:[^']|(?:''))*)((?<=\s*)TheVeryColumnIWantToFind(?=(?:\s+|=)))) I'm not sure if there is a more elegant RegEx (there'll most likely be one), but that's not important right now as it does the trick. To explain the RegEx in a few words: If it finds the column I'm after, it does a negative look-behind to figure out if the column name is used in a string literal. If so, it won't match. If not, it'll match. Back to the question. As I mentioned before, it won't work with Java. What will work and result in what I want? I found out, that Java does not seem to support unlimited look-behinds but still I couldn't get it to work. Isn't it right that a look-behind is always putting a limit up on itself from the search offset to the current search position? So it would result in something like "position - offset"?

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  • c# find nearest match to array of doubles

    - by Scott
    Given the code below, how do I compare a List of objects's values with a test value? I'm building a geolocation application. I'll be passing in longitude and latitude and would like to have the service answer back with the location closest to those values. I started down the path of converting to a string, and formatting the values down to two decimal places, but that seemed a bit too ghetto, and I'm looking for a more elegant solution. Any help would be great. Thanks, Scott public class Location : IEnumerable { public string label { get; set; } public double lat { get; set; } public double lon { get; set; } //Implement IEnumerable public IEnumerator GetEnumerator() { return (IEnumerator)this; } } [HandleError] public class HomeController : Controller { private List<Location> myList = new List<Location> { new Location { label="Atlanta Midtown", lon=33.657674, lat=-84.423130}, new Location { label="Atlanta Airport", lon=33.794151, lat=-84.387228}, new Location { label="Stamford, CT", lon=41.053758, lat=-73.530979}, ... } public static int Main(String[] args) { string inLat = "-80.987654"; double dblInLat = double.Parse(inLat); // here's where I would like to find the closest location to the inLat // once I figure out this, I'll implement the Longitude, and I'll be set }

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  • Android: How to keep onItemSelected from firing off on a newly instantiated Spinner

    - by Drennen
    I've thought of some less than elegant ways to solve this, but I know I must be missing something. My onItemSelected fires off immediately without any interaction with the user, and this is undesired behavior. I wish for the UI to wait until the user selects something before it does anything. I even tried setting up the listener in the onResume, hoping that would help, but it doesn't. How can I stop this from firing off before the user can touch the control? THANKS public class CMSHome extends Activity { private Spinner spinner; @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.main); // Heres my spinner /////////////////////////////////////////// spinner = (Spinner) findViewById(R.id.spinner); ArrayAdapter<CharSequence> adapter = ArrayAdapter.createFromResource( this, R.array.pm_list, android.R.layout.simple_spinner_item); adapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item); spinner.setAdapter(adapter); }; public void onResume() { super.onResume(); spinner.setOnItemSelectedListener(new MyOnItemSelectedListener()); } public class MyOnItemSelectedListener implements OnItemSelectedListener { public void onItemSelected(AdapterView<?> parent, View view, int pos, long id) { Intent i = new Intent(CMSHome.this, ListProjects.class); i.putExtra("bEmpID", parent.getItemAtPosition(pos).toString()); startActivity(i); Toast.makeText(parent.getContext(), "The pm is " + parent.getItemAtPosition(pos).toString(), Toast.LENGTH_LONG).show(); } public void onNothingSelected(AdapterView parent) { // Do nothing. } } }

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  • Support for nested model and class validation with ASP.NET MVC 2.0

    - by Diep-Vriezer
    I'm trying to validate a model containing other objects with validation rules using the System.ComponentModel.DataAnnotations attributes was hoping the default MVC implementation would suffice: var obj = js.Deserialize(json, objectInfo.ObjectType); if(!TryValidateModel(obj)) { // Handle failed model validation. } The object is composed of primitive types but also contains other classes which also use DataAnnotications. Like so: public class Entry { [Required] public Person Subscriber { get; set; } [Required] public String Company { get; set; } } public class Person { public String FirstName { get; set;} [Required] public String Surname { get; set; } } The problem is that the ASP.NET MVC validation only goes down 1 level and only evaluates the properties of the top level class, as can be read on digitallycreated.net/Blog/54/deep-inside-asp.net-mvc-2-model-metadata-and-validation. Does anyone know an elegant solution to this? I've tried xVal, but they seem to use a non-recursive pattern (http://blog.stevensanderson.com/2009/01/10/xval-a-validation-framework-for-aspnet-mvc/). Someone must have run into this problem before right? Nesting objects in your model doesn't seem so weird if you're designing a web service.

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  • Handle URI hacking gracefully in ASP.NET

    - by asbjornu
    I've written an application that handles most exceptions gracefully, with the page's design intact and a pretty error message. My application catches them all in the Page_Error event and there adds the exception to HttpContext.Curent.Context.Items and then does a Server.Transfer to an Error.aspx page. I find this to be the only viable solution in ASP.NET as there seems to be no other way to do it in a centralized and generic manner. I also handle the Application_Error and there I do some inspection on the exception that occurred to find out if I can handle it gracefully or not. Exceptions I've found I can handle gracefully are such that are thrown after someone hacking the URI to contain characters the .NET framework considers dangerous or basically just illegal at the file system level. Such URIs can look like e.g.: http://exmample.com/"illegal" http://example.com/illegal"/ http://example.com/illegal / (notice the space before the slash at the end of the last URI). I'd like these URIs to respond with a "404 Not Found" and a friendly message as well as not causing any error report to be sent to avoid DDOS attack vectors and such. I have, however, not found an elegant way to catch these types of errors. What I do now is inspect the exception.TargetSite.Name property, and if it's equal to CheckInvalidPathChars, ValidatePath or CheckSuspiciousPhysicalPath, I consider it a "path validation exception" and respond with a 404. This seems like a hack, though. First, the list of method names is probably not complete in any way and second, there's the possibility that these method names gets replaced or renamed down the line which will cause my code to break. Does anyone have an idea how I can handle this less hard-coded and much more future-proof way? PS: I'm using System.Web.Routing in my application to have clean and sensible URIs, if that is of any importance to any given solution.

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  • ListView item background via custom selector

    - by Gil
    Is it possible to apply a custom background to each Listview item via the list selector? The default selector specifies @android:color/transparent for the state_focused="false" case, but changing this to some custom drawable doesn't affect items that aren't selected. Romain Guy seems to suggest in this answer that this is possible. I'm currently achieving the same affect by using a custom background on each view and hiding it when the item is selected/focused/whatever so the selector is shown, but it'd be more elegant to have this all defined in one place. For reference, this is the selector I'm using to try and get this working: <selector xmlns:android="http://schemas.android.com/apk/res/android"> <item android:state_focused="false" android:drawable="@drawable/list_item_gradient" /> <!-- Even though these two point to the same resource, have two states so the drawable will invalidate itself when coming out of pressed state. --> <item android:state_focused="true" android:state_enabled="false" android:state_pressed="true" android:drawable="@drawable/list_selector_background_disabled" /> <item android:state_focused="true" android:state_enabled="false" android:drawable="@drawable/list_selector_background_disabled" /> <item android:state_focused="true" android:state_pressed="true" android:drawable="@drawable/list_selector_background_transition" /> <item android:state_focused="false" android:state_pressed="true" android:drawable="@drawable/list_selector_background_transition" /> <item android:state_focused="true" android:drawable="@drawable/list_selector_background_focus" /> </selector> And this is how I'm setting the selector: <ListView android:id="@android:id/list" android:layout_width="fill_parent" android:layout_height="fill_parent" android:listSelector="@drawable/list_selector_background" /> Thanks in advance for any help!

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  • How to detect if a Surface Contact is over a ScatterView?

    - by Bart Roozendaal
    This is a (kind of) similar situation as in the SDK Sample Shopping Cart for MS Surface. I have an application with two ScatterViews. The first covers the complete Surface window ('surface'). The second resides in a TagVisualization object ('pod'). There might be more than one pod available (if more than one tag is down on the table). I would like to be able to drag a ScatterViewItem from the 'pod' to the 'surface' or another 'pod'. I have no problems in detecting if a ScatterViewItem is leaving its ScatterView parent. Also, no problems in reparenting the ScatterViewItem. However, I want to detect which ScatterView the item is being dragged on. In the SDK Sample they have used a visual element (an ellipse in this case) which is below the ScatterViews. VisualTreeHelper.HitTest is used to determine if the contact is over the ellipse. If so, the 'connected' ScatterView is found. I don't think this is a very elegant solution. I wouldn't want a visual element put in there, just to detect if a contact is over a ScatterView. Are there betterwways to accomplish this kind of 'hittesting'? Thanks, Bart

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  • Echo styles into the mashup of a google map and wordpress custom fields

    - by zac
    Using wordpress, I am pulling in a custom fields from specific posts to fill in the content for a google generated map. I am using this code var point = new GLatLng(48.5139,-123.150531); var marker = createMarker(point,"Lime Kiln State Park", '<?php $post_id = 182; $my_post = get_post($post_id); $title = $my_post->post_title; $snip = get_post_meta($post_id, 'mapExcerpt', true); echo $title; echo $snip; ?>') map.addOverlay(marker); I am trying to echo css style blocks but this causes a javascript error var point = new GLatLng(48.5139,-123.150531); var marker = createMarker(point,"Lime Kiln State Park", '<?php $post_id = 182; $my_post = get_post($post_id); $title = $my_post->post_title; $snip = get_post_meta($post_id, 'mapExcerpt', true); echo "<div class='theTitle'>"; echo $title; echo "</div>"; echo $snip; ?>') map.addOverlay(marker); I get the error missing ) after argument list and the output is var point = new GLatLng(48.5139,-123.150531); var marker = createMarker(point,"Lime Kiln State Park", '<div class='theTitle'>Site Title</div>Site excerpt') map.addOverlay(marker); Can someone please show me a more elegant (working) solution for this?

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  • How do I get a PHP class constructor to call its parent's parent's constructor

    - by Paulo
    I need to have a class constructor in PHP call its parent's parent's (grandparent?) constructor without calling the parent constructor. // main class that everything inherits class Grandpa { public function __construct() { } } class Papa extends Grandpa { public function __construct() { // call Grandpa's constructor parent::__construct(); } } class Kiddo extends Papa { public function __construct() { // THIS IS WHERE I NEED TO CALL GRANDPA'S // CONSTRUCTOR AND NOT PAPA'S } } I know this is a bizarre thing to do and I'm attempting to find a means that doesn't smell bad but nonetheless, I'm curious if it's possible. EDIT I thought I should post the rationale for the chosen answer. The reason being; it most elegant solutionto the problem of wanting to call the "grandparent's" constructor while retaining all the values. It's certainly not the best approach nor is it OOP friendly, but that's not what the question was asking. For anyone coming across this question at a later date - Please find another solution. I was able to find a much better approach that didn't wreak havoc on the class structure. So should you.

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  • Obj-C component-based game architecture and message forwarding

    - by WanderWeird
    Hello, I've been trying to implement a simple component-based game object architecture using Objective-C, much along the lines of the article 'Evolve Your Hierarchy' by Mick West. To this end, I've successfully used a some ideas as outlined in the article 'Objective-C Message Forwarding' by Mike Ash, that is to say using the -(id)forwardingTargetForSelector: method. The basic setup is I have a container GameObject class, that contains three instances of component classes as instance variables: GCPositioning, GCRigidBody, and GCRendering. The -(id)forwardingTargetForSelector: method returns whichever component will respond to the relevant selector, determined using the -(BOOL)respondsToSelector: method. All this, in a way, works like a charm: I can call a method on the GameObject instance of which the implementation is found in one of the components, and it works. Of course, the problem is that the compiler gives 'may not respond to ...' warnings for each call. Now, my question is, how do I avoid this? And specifically regarding the fact that the point is that each instance of GameObject will have a different set of components? Maybe a way to register methods with the container objects, on a object per object basis? Such as, can I create some kind of -(void)registerMethodWithGameObject: method, and how would I do that? Now, it may or may not be obvious that I'm fairly new to Cocoa and Objective-C, and just horsing around, basically, and this whole thing may be very alien here. Of course, though I would very much like to know of a solution to my specific issue, anyone who would care to explain a more elegant way of doing this would additionally be very welcome. Much appreciated, -Bastiaan

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  • Re-ordering child nodes in django-MPTT

    - by Dominic Rodger
    I'm using Ben Firshman's fork of django-MPTT (hat tip to Daniel Roseman for the recommendation). I've got stuck trying to re-order nodes which share a common parent. I've got a list of primary keys, like this: ids = [5, 9, 7, 3] All of these nodes have a parent, say with primary key 1. At present, these nodes are ordered [5, 3, 9, 7], how can I re-order them to [5, 9, 7, 3]? I've tried something like this: last_m = MyModel.get(pk = ids.pop(0)) last_m.move_to(last_m.parent, position='first-child') for id in ids: m = MyModel.get(pk = id) m.move_to(last_m, position='right') Which I'd expect to do what I want, per the docs on move_to, but it doesn't seem to change anything. Sometimes it seems to move the first item in ids to be the first child of its parent, sometimes it doesn't. Am I right in my reading of the docs for move_to that calling move_to on a node n with position=right and a target which is a sibling of n will move n to immediately after the target? It's possible I've screwed up my models table in trying to figure this out, so maybe the code above is actually right. It's also possible there's a much more elegant way of doing this (perhaps one that doesn't involve O(n) selects and O(n) updates). Have I misunderstood something? Bonus question: is there a way of forcing django-MPTT to rebuild lft and rght values for all instances of a given model?

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  • How to use NInject (or other DI / IoC container) with the model binder in ASP.NET MVC 2 ?

    - by Andrei Rinea
    Let's say I have an User entity and I would want to set it's CreationTime property in the constructor to DateTime.Now. But being a unit test adopter I don't want to access DateTime.Now directly but use an ITimeProvider : public class User { public User(ITimeProvider timeProvider) { // ... this.CreationTime = timeProvider.Now; } // ..... } public interface ITimeProvider { public DateTime Now { get; } } public class TimeProvider : ITimeProvider { public DateTime Now { get { return DateTime.Now; } } } I am using NInject 2 in my ASP.NET MVC 2.0 application. I have a UserController and two Create methods (one for GET and one for POST). The one for GET is straight forward but the one for POST is not so straight and not so forward :P because I need to mess with the model binder to tell it to get a reference of an implementation of ITimeProvider in order to be able to construct an user instance. public class UserController : Controller { [HttpGet] public ViewResult Create() { return View(); } [HttpPost] public ActionResult Create(User user) { // ... } } I would also like to be able to keep all the features of the default model binder. Any chance to solve this simple/elegant/etc? :D

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  • Remove duplicates from a sorted ArrayList while keeping some elements from the duplicates

    - by js82
    Okay at first I thought this would be pretty straightforward. But I can't think of an efficient way to solve this. I figured a brute force way to solve this but that's not very elegant. I have an ArrayList. Contacts is a VO class that has multiple members - name, regions, id. There are duplicates in ArrayList because different regions appear multiple times. The list is sorted by ID. Here is an example: Entry 0 - Name: John Smith; Region: N; ID: 1 Entry 1 - Name: John Smith; Region: MW; ID: 1 Entry 2 - Name: John Smith; Region: S; ID: 1 Entry 3 - Name: Jane Doe; Region: NULL; ID: 2 Entry 4 - Name: Jack Black; Region: N; ID: 3 Entry 6 - Name: Jack Black; Region: MW; ID: 3 Entry 7 - Name: Joe Don; Region: NE; ID: 4 I want to transform the list to below by combining duplicate regions together for the same ID. Therefore, the final list should have only 4 distinct elements with the regions combined. So the output should look like this:- Entry 0 - Name: John Smith; Region: N,MW,S; ID: 1 Entry 1 - Name: Jane Doe; Region: NULL; ID: 2 Entry 2 - Name: Jack Black; Region: N,MW; ID: 3 Entry 3 - Name: Joe Don; Region: NE; ID: 4 What are your thoughts on the optimal way to solve this? I am not looking for actual code but ideas or tips to go about the best way to get it done. Thanks for your time!!!

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  • Update multiple rows with known keys without inserting new rows if nonexistent keys are found

    - by Kirzilla
    Hello, Let's imagine that we have table items... table: items item_id INT PRIMARY AUTO_INCREMENT title VARCHAR(255) views INT Let's imagine that it is filled with something like (1, item-1, 10), (2, item-2, 10), (3, item-3, 15) I want to make multi update view for this items from data taken from this array [item_id] = [views] '1' => '50', '2' => '60', '3' => '70', '5' => '10' IMPORTANT! Please note that we have item_id=5 in array, but we don't have item_id=5 in database. I can use INSERT ... ON DUPLICATE KEY UPDATE, but this way image_id=5 will be inserted into talbe items. How to avoid inserting new key? I just want item_id=5 be skipped because it is not in table. Of course, before execution I can select existing keys from items table; then compare with keys in array; delete nonexistent keys and perform INSERT ... ON DUPLICATE KEY UPDATE. But maybe there is some more elegant solutions? Thank you.

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  • Porting a select loop application to Android with NDK. Design question.

    - by plaisthos
    Hi, I have an network application which uses a select loop like this: bool shutdown=false; while (!shutdown) { [do something] select(...,timeout); } THe main loop cannot work like this in an Android application anymore since the application needs to receive Intents, need to handle GUI, etc. I think I have basically three possibilities: Move the main loop to the java part of the application. Let the loop run in its own thread and somehow communicate from/to java. Screw Android <= 2.3 and use a native activity and use AInputQueue/ALooper instead of select. The first possibility is not easy since java has no select which works on fds. Simply using the select and return after each loop to java is not an elegant possibility either since that requires setting the timeout to something like 20ms to have a good response time in the java part of the program. The second probability sound nicer but I have do some communication between java and the c++/c part of the program. Things that cold work: Using a socket, kind of ugly. using native calls in the "java gui thread" and callback from native in the "c thread". Both threads need to have thread safe implementations but this is managable. I have not explored the third possibility but I think that it is not the way to go. I think I can hack something together which will work but I asking what is the best path to chose.

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  • Mocking WebResponse's from a WebRequest

    - by Rob Cooper
    I have finally started messing around with creating some apps that work with RESTful web interfaces, however, I am concerned that I am hammering their servers every time I hit F5 to run a series of tests.. Basically, I need to get a series of web responses so I can test I am parsing the varying responses correctly, rather than hit their servers every time, I thought I could do this once, save the XML and then work locally. However, I don't see how I can "mock" a WebResponse, since (AFAIK) they can only be instantiated by WebRequest.GetResponse How do you guys go about mocking this sort of thing? Do you? I just really don't like the fact I am hammering their servers :S I dont want to change the code too much, but I expect there is a elegant way of doing this.. Update Following Accept Will's answer was the slap in the face I needed, I knew I was missing a fundamental point! Create an Interface that will return a proxy object which represents the XML. Implement the interface twice, on that uses WebRequest, the other that returns static "responses". The interface implmentation then either instantiates the return type based on the response, or the static XML. You can then pass the required class when testing or at production to the service layer. Once I have the code knocked up, I'll paste some samples. Thanks Will :)

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