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  • DataSets and XML - The Simplistic Approach

    One of the first ways I learned how to read xml data from external data sources was by using a DataSet’s ReadXML function. This function takes file path for an XML document and then converts it to a Dataset. This functionality is great when you need a simple way to process an XML document.  In addition the DataSet object also offers a simple way to save data in an xml format by using the WriteXML function. This function saves the current data in the DataSet to an XML file to be used later. DataSet ds  = New DataSet();String filePath = “http://www.yourdomain.com/someData.xml”;String fileSavePath = “C:\Temp\Test.xml”//Read file for this locationds.readxml(filePath);//Save file to this locationds.writexml(fileSavePath); I have used the ReadXML function before when consuming data from external Rss feeds to display on one of my sites.  It allows me to quickly pull in data from external sites with little to no processing. Example site: MyCreditTech.com

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  • What are the basic skills a BEGINNING JavaScript programmer should have?

    - by Sanford
    In NYC, we are working on creating a collaborative community programming environment and trying to segment out software engineers into differing buckets. At present, we are trying to define: Beginners Intermediates Advanced Experts (and/or Masters) Similar to an apprenticeship, you would need to demonstrate specific skills to achieve different levels. Right now, we have identified Beginner programming skills as: Object - method, attributes, inheritance Variable - math, string, array, boolean - all are objects Basic arithmetic functions - precedence of functions String manipulation Looping - flow control Conditionals - boolean algebra This is a first attempt, and it is a challenge since we know the natural tension between programming and software engineering. How would you create such a skills-based ranking for JavaScript in this manner? For example, what would be the Beginner Javascript skills that you would need to have to advance to the Intermediate Training? And so on.

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  • jqGrid - dynamically load different drop down values for different rows depending on another column value

    - by Renso
    Goal: As we all know the jqGrid examples in the demo and the Wiki always refer to static values for drop down boxes. This of course is a personal preference but in dynamic design these values should be populated from the database/xml file, etc, ideally JSON formatted. Can you do this in jqGrid, yes, but with some custom coding which we will briefly show below (refer to some of my other blog entries for a more detailed discussion on this topic). What you CANNOT do in jqGrid, referrign here up and to version 3.8.x, is to load different drop down values for different rows in the jqGrid. Well, not without some trickery, which is what this discussion is about. Issue: Of course the issue is that jqGrid has been designed for high performance and thus I have no issue with them loading a  reference to a single drop down values list for every column. This way if you have 500 rows or one, each row only refers to a single list for that particuolar column. Nice! SO how easy would it be to simply traverse the grid once loaded on gridComplete or loadComplete and simply load the select tag's options from scratch, via ajax, from memory variable, hard coded etc? Impossible! Since their is no embedded SELECT tag within each cell containing the drop down values (remeber it only has a reference to that list in memory), all you will see when you inspect the cell prior to clicking on it, or even before and on beforeEditCell, is an empty <TD></TD>. When trying to load that list via a click event on that cell will temporarily load the list but jqGrid's last internal callback event will remove it and replace it with the old one, and you are back to square one. Solution: Yes, after spending a few hours on this found a solution to the problem that does not require any updates to jqGrid source code, thank GOD! Before we get into the coding details, the solution here can of course be customized to suite your specific needs, this one loads the entire drop down list that would be needed across all rows once into global variable. I then parse this object that contains all the properties I need to filter the rows depending on which ones I want the user to see based off of another cell value in that row. This only happens when clicking the cell, so no performance penalty. You may of course to load it via ajax when the user clicks the cell, but I found it more effecient to load the entire list as part of jqGrid's normal editoptions: { multiple: false, value: listingStatus } colModel options which again keeps only a reference to the sinlge list, no duplciation. Lets get into the meat and potatoes of it.         var acctId = $('#Id').val();         var data = $.ajax({ url: $('#ajaxGetAllMaterialsTrackingLookupDataUrl').val(), data: { accountId: acctId }, dataType: 'json', async: false, success: function(data, result) { if (!result) alert('Failure to retrieve the Alert related lookup data.'); } }).responseText;         var lookupData = eval('(' + data + ')');         var listingCategory = lookupData.ListingCategory;         var listingStatus = lookupData.ListingStatus;         var catList = '{';         $(lookupData.ListingCategory).each(function() {             catList += this.Id + ':"' + this.Name + '",';         });         catList += '}';         var lastsel;         var ignoreAlert = true;         $(item)         .jqGrid({             url: listURL,             postData: '',             datatype: "local",             colNames: ['Id', 'Name', 'Commission<br />Rep', 'Business<br />Group', 'Order<br />Date', 'Edit', 'TBD', 'Month', 'Year', 'Week', 'Product', 'Product<br />Type', 'Online/<br />Magazine', 'Materials', 'Special<br />Placement', 'Logo', 'Image', 'Text', 'Contact<br />Info', 'Everthing<br />In', 'Category', 'Status'],             colModel: [                 { name: 'Id', index: 'Id', hidden: true, hidedlg: true },                 { name: 'AccountName', index: 'AccountName', align: "left", resizable: true, search: true, width: 100 },                 { name: 'OnlineName', index: 'OnlineName', align: 'left', sortable: false, width: 80 },                 { name: 'ListingCategoryName', index: 'ListingCategoryName', width: 85, editable: true, hidden: false, edittype: "select", editoptions: { multiple: false, value: eval('(' + catList + ')') }, editrules: { required: false }, formatoptions: { disabled: false} }             ],             jsonReader: {                 root: "List",                 page: "CurrentPage",                 total: "TotalPages",                 records: "TotalRecords",                 userdata: "Errors",                 repeatitems: false,                 id: "0"             },             rowNum: $rows,             rowList: [10, 20, 50, 200, 500, 1000, 2000],             imgpath: jQueryImageRoot,             pager: $(item + 'Pager'),             shrinkToFit: true,             width: 1455,             recordtext: 'Traffic lines',             sortname: 'OrderDate',             viewrecords: true,             sortorder: "asc",             altRows: true,             cellEdit: true,             cellsubmit: "remote",             cellurl: editURL + '?rows=' + $rows + '&page=1',             loadComplete: function() {               },             gridComplete: function() {             },             loadError: function(xhr, st, err) {             },             afterEditCell: function(rowid, cellname, value, iRow, iCol) {                 var select = $(item).find('td.edit-cell select');                 $(item).find('td.edit-cell select option').each(function() {                     var option = $(this);                     var optionId = $(this).val();                     $(lookupData.ListingCategory).each(function() {                         if (this.Id == optionId) {                                                       if (this.OnlineName != $(item).getCell(rowid, 'OnlineName')) {                                 option.remove();                                 return false;                             }                         }                     });                 });             },             search: true,             searchdata: {},             caption: "List of all Traffic lines",             editurl: editURL + '?rows=' + $rows + '&page=1',             hiddengrid: hideGrid   Here is the JSON data returned via the ajax call during the jqGrid function call above (NOTE it must be { async: false}: {"ListingCategory":[{"Id":29,"Name":"Document Imaging & Management","OnlineName":"RF Globalnet"} ,{"Id":1,"Name":"Ancillary Department Hardware","OnlineName":"Healthcare Technology Online"} ,{"Id":2,"Name":"Asset Tracking","OnlineName":"Healthcare Technology Online"} ,{"Id":3,"Name":"Asset Tracking","OnlineName":"Healthcare Technology Online"} ,{"Id":4,"Name":"Asset Tracking","OnlineName":"Healthcare Technology Online"} ,{"Id":5,"Name":"Document Imaging & Management","OnlineName":"Healthcare Technology Online"} ,{"Id":6,"Name":"Document Imaging & Management","OnlineName":"Healthcare Technology Online"} ,{"Id":7,"Name":"EMR/EHR Software","OnlineName":"Healthcare Technology Online"}]} I only need the Id and Name for the drop down list, but the third column in the JSON object is important, it is the only that I match up with the OnlineName in the jqGrid column, and then in the loop during afterEditCell simply remove the ones I don't want the user to see. That's it!

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  • Techniques for separating game model from presentation

    - by liortal
    I am creating a simple 2D game using XNA. The elements that make up the game world are what i refer to as the "model". For instance, in a board game, i would have a GameBoard class that stores information about the board. This information could be things such as: Location Size Details about cells on the board (occupied/not occupied) etc This object should either know how to draw itself, or describe how to draw itself to some other entity (renderer) in order to be displayed. I believe that since the board only contains the data+logic for things regarding it or cells on it, it should not provide the logic of how to draw things (separation of concerns). How can i achieve a good partitioning and easily allow some other entity to draw it properly? My motivations for doing so are: Allow multiple "implementations" of presentation for a single game entity Easier porting to other environments where the presentation code is not available (for example - porting my code to Unity or other game technology that does not rely on XNA).

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  • How would you want to see software intellectual property protected?

    - by glenatron
    Reading answers to this question - and many other discussions of software patents - it seems that most of us as programmers feel that software patents are a bad idea. At the same time we are in the group most likely to lose out if our work is copied or stolen. So what level of Intellectual Property Protection does code and software need? Is copyright sufficient? Are patents necessary? As software is neither a physical object nor simple text, should we be thinking of a third path that falls somewhere between the two? Do we need any protection at all? If you had the facility to set up the law for this, what would you choose?

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  • iOS Support with Windows Azure Mobile Services – now with Push Notifications

    - by ScottGu
    A few weeks ago I posted about a number of improvements to Windows Azure Mobile Services. One of these was the addition of an Objective-C client SDK that allows iOS developers to easily use Mobile Services for data and authentication.  Today I'm excited to announce a number of improvement to our iOS SDK and, most significantly, our new support for Push Notifications via APNS (Apple Push Notification Services).  This makes it incredibly easy to fire push notifications to your iOS users from Windows Azure Mobile Service scripts. Push Notifications via APNS We've provided two complete tutorials that take you step-by-step through the provisioning and setup process to enable your Windows Azure Mobile Service application with APNS (Apple Push Notification Services), including all of the steps required to configure your application for push in the Apple iOS provisioning portal: Getting started with Push Notifications - iOS Push notifications to users by using Mobile Services - iOS Once you've configured your application in the Apple iOS provisioning portal and uploaded the APNS push certificate to the Apple provisioning portal, it's just a matter of uploading your APNS push certificate to Mobile Services using the Windows Azure admin portal: Clicking the “upload” within the “Push” tab of your Mobile Service allows you to browse your local file-system and locate/upload your exported certificate.  As part of this you can also select whether you want to use the sandbox (dev) or production (prod) Apple service: Now, the code to send a push notification to your clients from within a Windows Azure Mobile Service is as easy as the code below: push.apns.send(deviceToken, {      alert: 'Toast: A new Mobile Services task.',      sound: 'default' }); This will cause Windows Azure Mobile Services to connect to APNS (Apple Push Notification Service) and send a notification to the iOS device you specified via the deviceToken: Check out our reference documentation for full details on how to use the new Windows Azure Mobile Services apns object to send your push notifications. Feedback Scripts An important part of working with any PNS (Push Notification Service) is handling feedback for expired device tokens and channels. This typically happens when your application is uninstalled from a particular device and can no longer receive your notifications. With Windows Notification Services you get an instant response from the HTTP server.  Apple’s Notification Services works in a slightly different way and provides an additional endpoint you can connect to poll for a list of expired tokens. As with all of the capabilities we integrate with Mobile Services, our goal is to allow developers to focus more on building their app and less on building infrastructure to support their ideas. Therefore we knew we had to provide a simple way for developers to integrate feedback from APNS on a regular basis.  This week’s update now includes a new screen in the portal that allows you to optionally provide a script to process your APNS feedback – and it will be executed by Mobile Services on an ongoing basis: This script is invoked periodically while your service is active. To poll the feedback endpoint you can simply call the apns object's getFeedback method from within this script: push.apns.getFeedback({       success: function(results) {           // results is an array of objects with a deviceToken and time properties      } }); This returns you a list of invalid tokens that can now be removed from your database. iOS Client SDK improvements Over the last month we've continued to work with a number of iOS advisors to make improvements to our Objective-C SDK. The SDK is being developed under an open source license (Apache 2.0) and is available on github. Many of the improvements are behind the scenes to improve performance and memory usage. However, one of the biggest improvements to our iOS Client API is the addition of an even easier login method.  Below is the Objective-C code you can now write to invoke it: [client loginWithProvider:@"twitter"                     onController:self                        animated:YES                      completion:^(MSUser *user, NSError *error) {      // if no error, you are now logged in via twitter }]; This code will automatically present and dismiss our login view controller as a modal dialog on the specified controller.  This does all the hard work for you and makes login via Twitter, Google, Facebook and Microsoft Account identities just a single line of code. My colleague Josh just posted a short video demonstrating these new features which I'd recommend checking out: Summary The above features are all now live in production and are available to use immediately.  If you don’t already have a Windows Azure account, you can sign-up for a free trial and start using Mobile Services today. Visit the Windows Azure Mobile Developer Center to learn more about how to build apps with Mobile Services. Hope this helps, Scott P.S. In addition to blogging, I am also now using Twitter for quick updates and to share links. Follow me at: twitter.com/scottgu

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  • Creating a SOLID Visual Studio Solution

    The SOLID acronym describes five object-oriented design principles that, when followed, produce code that is cleaner and more maintainable. The last principle, the Dependency Inversion Principle, suggests that details depend upon abstractions. Unfortunately, typical project relationships in .NET applications can make this principle difficult to follow. In this article, I'll describe how one can structure a set of projects in a Visual Studio solution such that DIP can be followed, allowing for the creation of a SOLID solution. You can download the sample solution and use it as a starting point for your new solutions if you like.

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  • How do you navigate and refactor code written in a dynamic language?

    - by Philippe Beaudoin
    I love that writing Python, Ruby or Javascript requires so little boilerplate. I love simple functional constructs. I love the clean and simple syntax. However, there are three things I'm really bad at when developing a large software in a dynamic language: Navigating the code Identifying the interfaces of the objects I'm using Refactoring efficiently I have been trying simple editors (i.e. Vim) as well as IDE (Eclipse + PyDev) but in both cases I feel like I have to commit a lot more to memory and/or to constantly "grep" and read through the code to identify the interfaces. As for refactoring, for example changing method names, it becomes hugely dependent on the quality of my unit tests. And if I try to isolate my unit tests by "cutting them off" the rest of the application, then there is no guarantee that my stub's interface stays up to date with the object I'm stubbing. I'm sure there are workarounds for these problems. How do you work efficiently in Python, Ruby or Javascript?

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  • What functionality should I use in OpenGL 2.0?

    - by Jeffrey
    Considering OpenGL 2.1, we all know that glBegin and glEnd are the devil. Should I use only VBO to render 3d primitives (I can't find VAO in that version, weren't there already?)? Should I still use the matrix stack (why not?)? Should I still use glFrustum? Can I take advantage of shaders in GLSL 1.20? Where can I find a tutorial for VBO in OpenGL 2.1 and the "correct" way of programming in it? Also how am I supposed to animate something. Like a cube moving around an object or a player moving in the scene (static vbo data + shader?)? Note: Take your time to answer this question, I'll accept an answer tomorrow.

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  • How can I get accurate collision resolution on the corners of rectangles?

    - by ssb
    I have a working collision system implemented, and it's based on minimum translation vectors. This works fine in most cases except when the minimum translation vector is not actually in the direction of the collision. For example: When a rectangle is on the far edge on any side of another rectangle, a force can be applied, in this example down, the pushes one rectangle into the other, particularly a static object like a wall or a floor. As in the picture, the collision is coming from above, but because it's on the very edge, it translates to the left instead of back up. I've searched for a while to find an approach but everything I can find deals with general corner collisions where my problem is only in this one limited case. Any suggestions?

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  • Career Development: What should I learn next after Python? and Why? [closed]

    - by Josh
    Hi all I'm currently learning Python. I want to know what should I learn next out of these programming langauages: PHP Actionscript 3 Objective-C (iPhone applications) I work in the Multimedia industry and have decided to learn Python as a first programming language seriously because I would like to learn the basics of programming, to mainly write scripts at work that Automate task (eg. Edit multiple XML files quickly) At work we have a senior developer who knows Actionscript and PHP very well (although knows PHP better). We also have been developing iPhone applications for 2 weeks, Our senior developer could learn it although we have lots of work currently with PHP and Actionscript 3 type work and haven't had time or reason to pick up iOS development. Here are the reasons I want to learn each language, But I cannot decide what I'll learn next: PHP: I want to learn PHP because it will help with Web Development. PHP is very wanted by employers. Senior developer at work writes everything in it web sites, CMS etc. (including XML checks and scripts), I will learn a lot from him (once I learn the basics). However, I don't want to learn Web because you have to deal with lots of cross-browser problems. Actionscript 3: At work we are looking to put on another developer to help with online activities and very small games (using Actionscript 3.0 and Flash CS5) for (eg. First Aid Activities etc) I would like to do things that have a element of design as I'm better at Photoshop then developing. I want to be creative, I like to interact with users in a fun way. Objective-C (iPhone applications): We are a all mac office, we may get more iPhone, iPad application work(jobs) that need to be created. Work has found it nearly impossible to find good iPhone developers. I like apple products (Macs and iPhones), I would like to make my own games, applications in my spare time(if I knew how). Should I learn Actionscript first because it would be easier to learn then Objective-C? Should I learn PHP because it is very widely used? Should I learn Objective-C because it is really wanted by employers now?

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  • How to select li range and move them inside div [closed]

    - by user8012
    How can I select a range of li and move them inside div element. For example: <ul> <li>test</li> <li>test</li> <li>test</li> <li>test</li> <li>test</li> <li>test</li> <li>test</li> <li>test</li> <li>test</li> <li>test</li> <li>test</li> <li>test</li> </ul> If the li is more than 6 create a column like this: <ul> <li> <div class="column1"> <ul> <li>test</li> <li>test</li> <li>test</li> <li>test</li> <li>test</li> <li>test</li> </ul> </div> </li> <li> <div class="column2"> <ul> <li>test</li> <li>test</li> <li>test</li> <li>test</li> <li>test</li> <li>test</li> </ul> </div> </li> </ul>

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  • Mobile Multiplayer games and coping with high latency

    - by spaceOwl
    I'm currently researching regarding a design for an online (realtime) mobile multiplayer game. As such, i'm taking into consideration that latencies (lag) is going to be high (perhaps higher than PC/consoles). I'd like to know if there are ways to overcome this or minimize the issues of high latency? The model i'll be using is peer-to-peer (using Photon cloud to broadcast messages to all other players). How do i deal with a scenario where a message about a local object's state at time t will only get to other players at *t + HUGE_LAG* ?

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  • Make objects slide across the screen in random positions

    - by user3475907
    I want to make an object appear randomly at the right hand side of the screen and then slide across the screen and disapear at the left hand side. I am working with libgdx. I have this bit of code but it makes items fall from the top down. Please help. public EntityManager(int amount, OrthoCamera camera) { player = new Player(new Vector2(15, 230), new Vector2(0, 0), this, camera); for (int i = 0; i < amount; i++) { float x = MathUtils.random(0, MainGame.HEIGHT - TextureManager.ENEMY.getHeight()); float y = MathUtils.random(MainGame.WIDTH, MainGame.WIDTH * 10); float speed = MathUtils.random(2, 10); addEntity(new Enemy(new Vector2(x, y), new Vector2(-0, -speed))); }

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  • Why is database developer pay so high? [closed]

    - by user433500
    Just wondering why someone would get 10k+ in some area in US for just writing queries and creating tables. While the average salary for someone who does scripting, object oriented programming, J2EE and database all together is only ~12K in new york city. Is there similar opportunities in cities like new york where only doing database gets one 10K+? What is the rational of companies paying such a high salary to consultants for just writing simple queries? I am sure college grad can do that with ease and will be quite satisfied with a 60k+ pay for a couple of year. Does location really matter so much?

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  • Cost of maintenance depending on paradigms

    - by Anto
    Is there any data on which paradigms allow for code which is easier/cheaper to maintain? Certainly, independantly of the chosen paradigm, good design is cheaper to maintain than bad, but there should probably be major differences coming only from the paradigm choice. Unstructured programming, for instance, generates very messy code (spaghetti code) which is expensive to maintain. In object oriented programming, implementation details are hidden and thus it should be pretty cheap to change those. In functional programming, there are no side effects, thus there is lesser risk of introducing bugs during maintainance, which should be cheaper. Is there any data on which paradigms are the most cost-efficient when coming down to maintenance? If no such data exists, what is your take on the question?

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  • Is there a quasi-standard set of attributes to annotate thread safety, immutability etc.?

    - by Eugene Beresovksy
    Except for a blog post here and there, describing the custom attributes someone created, but that do not seem to get any traction - like one describing how to enforce immutability, another one on Documenting Thread Safety, modeling the attributes after JCIP annotations - is there any standard emerging? Anything MS might be planning for the future? This is something that should be standard, if there's to be any chance of interoperability between libraries concurrency-wise. Both for documentation purposes, and also to feed static / dynamic test tools. If MS isn't doing anything in that direction, it could be done on CodePlex - but I couldn't find anything there, either. <opinion>Concurrency and thread safety are really hard in imperative and object-languages like C# and Java, we should try to tame it, until we hopefully switch to more appropriate languages.</opinion>

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  • What''s easy extensible technique to store game data?

    - by Miro
    I'm looking for library/technique for storing my game resources - levels, object (effects,world info), items(price,effects,...), NPC(visual info, behavior), everything except graphics/audio stuff. I've seen lua used for Awesome WM configuration. protobuf looks good, but it seems to be designed for network communication. I've tried to write my own parser, but as the project grows it's more and more harder to manage it and catch all the bugs. My requiremets: stability easy extension of data without need to convert older versions to newer good(don't have to be the best) performance of loading not much coding not XML!

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  • JavaOne Latin America 2011: Keynotes, Sessions, Hands-on Lab, Geek Bike Ride, etc.

    - by arungupta
    After a very successful JavaOne San Francisco, the first JavaOne on the road for 2011 is heading to Latin America next week. There are 59 sessions delivered by several rock star speakers and with 60% sessions delivered by the local community. There are strategy, technical and community keynotes. The community keynote on Thursday will particularly be lot of fun with appearances from Java Champions, JUG leaders, jHome, and several others. Also check out the Exhibitor Floor Plan and don't forget to Register! The complete session schedule gives an overview for the list of technical sessions and hands-on lab. There are several Java EE, GlassFish, and WebLogic sessions and are highlighted below: Tuesday, Dec 6 Oracle WebLogic Server XML-Free Programming: Java Server and Client Development without <> Java EE Application in Production: Tips and Tricks to achieve zero downtime Web Applications and Wicket Scala on GlassFish and Java EE 6 REST and Java best practices, issues and solutions for the Enterprise Building a RESTful Web Application with JAX-RS and Ext JS 4 Wednesday, Dec 7 Oracle GlassFish Server in the Virtual World JAX-RS 2.0: What's in JSR 339 ? JSF 343: What's coming in Java Message Service 2.0 ? The Great News of JSF 2.0! Thursday, Dec 8 Servlet 3.1 Update Develop, Deploy, and Monitor a Java EE 6 Application with Clustered GlassFish 3.1 Migrating from EJB/SOAP to REST with JAX-RS: The Case of the Central Bank of Brazil GlassFish REST Administration Back End: An Insider look at a real REST Application Scripting and Agile Java EE Applications with Jython And this is Brazil so a fun element is important. There are the usual Caiprihinas, Churrascaria, late night social dinners, community engagement, and multiple other fun activities. Fabiane Nardon and SOUJava gang are also organizing a Geek Bike Ride on the Sunday (Dec 4th) before JavaOne. The 20k ride (map) starts at 7am and goes through the streets of Sao Paulo. This is an opportunity to meet some of the JavaOne speakers and attendees outside the conference. They've even designed a t-shirt and 32 geeks have signed up so far. I'm glad my discussion with Fabiane during FISL early this year for arranging this bike ride is finally taking shape! I'm definitely looking forward to it and will be bringing nice fruity Odwalla bars for all the riders. Be there to ride with me and many others :-) Stay updated by following @oracledobrasil and @javaoneconf. I'll be there, will you ? Don't wait and register now! And in case you are interested in reading about the experience from last year ... it was lot of fun! Just check out a collage of pictures yourself ... And the complete album at:

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  • How granular should a command be in a CQ[R]S model?

    - by Aaronaught
    I'm considering a project to migrate part of our WCF-based SOA over to a service bus model (probably nServiceBus) and using some basic pub-sub to achieve Command-Query Separation. I'm not new to SOA, or even to service bus models, but I confess that until recently my concept of "separation" was limited to run-of-the-mill database mirroring and replication. Still, I'm attracted to the idea because it seems to provide all the benefits of an eventually-consistent system while sidestepping many of the obvious drawbacks (most notably the lack of proper transactional support). I've read a lot on the subject from Udi Dahan who is basically the guru on ESB architectures (at least in the Microsoft world), but one thing he says really puzzles me: As we get larger entities with more fields on them, we also get more actors working with those same entities, and the higher the likelihood that something will touch some attribute of them at any given time, increasing the number of concurrency conflicts. [...] A core element of CQRS is rethinking the design of the user interface to enable us to capture our users’ intent such that making a customer preferred is a different unit of work for the user than indicating that the customer has moved or that they’ve gotten married. Using an Excel-like UI for data changes doesn’t capture intent, as we saw above. -- Udi Dahan, Clarified CQRS From the perspective described in the quotation, it's hard to argue with that logic. But it seems to go against the grain with respect to SOAs. An SOA (and really services in general) are supposed to deal with coarse-grained messages so as to minimize network chatter - among many other benefits. I realize that network chatter is less of an issue when you've got highly-distributed systems with good message queuing and none of the baggage of RPC, but it doesn't seem wise to dismiss the issue entirely. Udi almost seems to be saying that every attribute change (i.e. field update) ought to be its own command, which is hard to imagine in the context of one user potentially updating hundreds or thousands of combined entities and attributes as it often is with a traditional web service. One batch update in SQL Server may take a fraction of a second given a good highly-parameterized query, table-valued parameter or bulk insert to a staging table; processing all of these updates one at a time is slow, slow, slow, and OLTP database hardware is the most expensive of all to scale up/out. Is there some way to reconcile these competing concerns? Am I thinking about it the wrong way? Does this problem have a well-known solution in the CQS/ESB world? If not, then how does one decide what the "right level" of granularity in a Command should be? Is there some "standard" one can use as a starting point - sort of like 3NF in databases - and only deviate when careful profiling suggests a potentially significant performance benefit? Or is this possibly one of those things that, despite several strong opinions being expressed by various experts, is really just a matter of opinion?

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  • What are deferred callbacks?

    - by tentimes
    I understand the idea of a callback, where I pass a function into another function and that function then uses the supplied function at will. I am struggling to understand deferred callbacks, even after googling it. Could someone provide a simple explanation please? I program in Ruby, but also know C/C++ a bit, but most of all I was a experienced assembly language programmer. So I am wondering is it a bit like a stack of callback addresses that get pop'd? I am hoping to learn jquery or node.js and these deferred callbacks seem integral to both. I understand basic threading principles (though mutex object makes my head hurt ;)

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  • Ripping MP3s in Rhythmbox Ubuntu 12.10 (64 bit)?

    - by James Fellows Yates
    I installed a couple of days ago Ubuntu 12.10 (64 bit). I today tried ripping a CD in the MP3 format. However, whenever I try to rip, it says it is missing an extra multimedia plugin "Gstreamer extra plug-ins (i386)". I then try to install the :i386 version of the gstreamer-ugly plugins, but then I get the same problem but with the id3-demuxer (or something similar) The Terminal output I get from both problems (but replace the "MPEG-1 Layer 3 (MP3) encoder" with the "ID3-demuxer" name) is: james@clefairy:~$ rhythmbox (rhythmbox:24122): GLib-GObject-CRITICAL **: g_object_unref: assertion `G_IS_OBJECT (object)' failed Rhythmbox-Message: Missing plugin: gstreamer|0.10|rhythmbox|MPEG-1 Layer 3 (MP3) encoder|encoder-audio/mpeg, mpegversion=(int)1, layer=(int)3 /usr/lib/python2.7/dist-packages/gobject/constants.py:24: Warning: g_boxed_type_register_static: assertion `g_type_from_name (name) == 0' failed import gobject._gobject It doesn't help that each time I have to install/remove the entire Gstreamer-ugly collection each time - I can't find that specific file. The CD plays fine, it's the ripping plugin that doesn't seem to work. I didn't have this problem previously on 12.04 (64 bit).

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  • In OpenGl ES 2, should I allocate multiple transformation matrices?

    - by thm4ter
    In OpenGl ES 2, should I declare just one transformation matrix, and share it across all objects or should I declare a transformation matrix in each object that needs it? for clarification... something like this: public class someclass{ public static float[16] transMatrix = new float[16]; ... public static void translate(int x, int y){ //do translation here } } public class someotherclass{ ... void draw(GL10 unused){ someclass.translate(10,10); //draw } } verses something like this: public class obj1{ public static float[16] transMatrix = new float[16]; ... void draw(GL10 unused){ //translate //draw } } public class obj2{ public static float[16] transMatrix = new float[16]; ... void draw(GL10 unused){ //translate //draw } }

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  • concurrency::index<N> from amp.h

    - by Daniel Moth
    Overview C++ AMP introduces a new template class index<N>, where N can be any value greater than zero, that represents a unique point in N-dimensional space, e.g. if N=2 then an index<2> object represents a point in 2-dimensional space. This class is essentially a coordinate vector of N integers representing a position in space relative to the origin of that space. It is ordered from most-significant to least-significant (so, if the 2-dimensional space is rows and columns, the first component represents the rows). The underlying type is a signed 32-bit integer, and component values can be negative. The rank field returns N. Creating an index The default parameterless constructor returns an index with each dimension set to zero, e.g. index<3> idx; //represents point (0,0,0) An index can also be created from another index through the copy constructor or assignment, e.g. index<3> idx2(idx); //or index<3> idx2 = idx; To create an index representing something other than 0, you call its constructor as per the following 4-dimensional example: int temp[4] = {2,4,-2,0}; index<4> idx(temp); Note that there are convenience constructors (that don’t require an array argument) for creating index objects of rank 1, 2, and 3, since those are the most common dimensions used, e.g. index<1> idx(3); index<2> idx(3, 6); index<3> idx(3, 6, 12); Accessing the component values You can access each component using the familiar subscript operator, e.g. One-dimensional example: index<1> idx(4); int i = idx[0]; // i=4 Two-dimensional example: index<2> idx(4,5); int i = idx[0]; // i=4 int j = idx[1]; // j=5 Three-dimensional example: index<3> idx(4,5,6); int i = idx[0]; // i=4 int j = idx[1]; // j=5 int k = idx[2]; // k=6 Basic operations Once you have your multi-dimensional point represented in the index, you can now treat it as a single entity, including performing common operations between it and an integer (through operator overloading): -- (pre- and post- decrement), ++ (pre- and post- increment), %=, *=, /=, +=, -=,%, *, /, +, -. There are also operator overloads for operations between index objects, i.e. ==, !=, +=, -=, +, –. Here is an example (where no assertions are broken): index<2> idx_a; index<2> idx_b(0, 0); index<2> idx_c(6, 9); _ASSERT(idx_a.rank == 2); _ASSERT(idx_a == idx_b); _ASSERT(idx_a != idx_c); idx_a += 5; idx_a[1] += 3; idx_a++; _ASSERT(idx_a != idx_b); _ASSERT(idx_a == idx_c); idx_b = idx_b + 10; idx_b -= index<2>(4, 1); _ASSERT(idx_a == idx_b); Usage You'll most commonly use index<N> objects to index into data types that we'll cover in future posts (namely array and array_view). Also when we look at the new parallel_for_each function we'll see that an index<N> object is the single parameter to the lambda, representing the (multi-dimensional) thread index… In the next post we'll go beyond being able to represent an N-dimensional point in space, and we'll see how to define the N-dimensional space itself through the extent<N> class. Comments about this post by Daniel Moth welcome at the original blog.

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  • How to See Which Group Policies are Applied to Your PC and User Account

    - by Taylor Gibb
    We have shown you a lot of tips and tricks here at How-To Geek that require the modification of  a Group Policy Object. Over time you may have wondered which Group Policy settings you have edited–so here’s how to figure that out. Note: This will work on Windows 7 Professional and higher, as well as the Windows 8 Release Preview. HTG Explains: What Is RSS and How Can I Benefit From Using It? HTG Explains: Why You Only Have to Wipe a Disk Once to Erase It HTG Explains: Learn How Websites Are Tracking You Online

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