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  • JSF 2.2 Update from Ed Burns

    - by arungupta
    In a recent interview the JavaServer Faces specification lead, Ed Burns, gave an update on JSF 2.2. This is a required component of the Java EE 7 platform. The work is expected to wrap up by CY 2012 and the schedule is publicly available. The interview provide an update on how Tenant Scope from CDI and multi-templating will be included. It also provide details on which HTML 5 content categories will be addressed. The EG discussions are mirrored at jsr344-experts@javaserverfaces-spec-public. You can also participate in the discussion by posting a message to users@javaserverfaces-spec-public. All the mailing lists are open for subscription anyway and JIRA for spec provide more details about features targeted for the upcoming release. A blog at J-Development provide complete details about the new features coming in this version. And an Early Draft of the specification is available for some time now.

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  • Ed Burns' Servlet 4/HTTP 2 Session at JavaOne 2014

    - by reza_rahman
    For the Java EE track at JavaOne 2014 we are highlighting some key sessions and speakers to better inform you of what you can expect, right up until the start of the conference. To this end we recently interviewed Ed Burns. Ed is a veteran of Sun and now Oracle. He has been and is instrumental in pushing the JSF ecosystem forward as specification lead. Besides his specification lead work Ed is well regarded as an author and speaker on his own right. In addition to carrying the JSF torch Ed will be co-leading the key Servlet 4 specification for Java EE 8, along with Servlet specification guru Shing Wai Chan. The primary goal of Servlet 4 is to enable the fundamentally important changes in HTTP 2 for the entire server-side Java ecosystem. We wanted to talk to Ed about his Servlet 4 session at JavaOne 2014 and HTTP 2 generally: The details for the Servlet 4 session can be found here. Ed has several other key sessions on the track that we hope to talk to him about separately in the near future: What’s Next for JSF?: In this key session, Ed will be sharing the next steps for the continued evolution of the JSF specification in Java EE 8. Where’s My UI? The 2014 JavaOne Web App UI Smackdown: The UI space for web applications, especially in the Java ecosystem continues to be as hotly contested as ever. This is especially true with the (re)introduction of JavaScript based rich client frameworks like AngularJS. This lively panel brings together experts representing the diverse schools of thought for web UIs. Ed will be representing JSF of course. Neal Ford will moderate the panel as an independent and hopefully reasonably neutral party. Adopt-a-JSR for Java EE 7 and Java EE 8: Adopt-a-JSR has been a reasonable success for Java EE 7. With Java EE 8 we are planning to strengthen it far more as away of getting grassroots level participation in the specification efforts. This session will introduce Adopt-a-JSR, share how it worked for Java EE 7 and what we plan to do with it in Java EE 8. Ed will be sharing his perspectives on Adopt-a-JSR for both Java EE 7 and Java EE 8. Besides Ed's sessions, we have a very strong program for the Java EE track and JavaOne overall - just explore the content catalog. If you can't make it, you can be assured that we will make key content available after the conference just as we have always done.

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  • Ed Burns' Servlet 4/HTTP 2 Session at JavaOne

    - by Yolande Poirier
    By Guest Blogger Reza Rahman For the Java EE track at JavaOne 2014 we are highlighting some key sessions and speakers to better inform you of what you can expect, right up until the start of the conference. To this end we recently interviewed Ed Burns. Ed is a veteran of Sun and now Oracle. He has been and is instrumental in pushing the JSF ecosystem forward as specification lead. Besides his specification lead work Ed is well regarded as an author and speaker on his own right. In addition to carrying the JSF torch Ed will be co-leading the key Servlet 4 specification for Java EE 8, along with Servlet specification guru Shing Wai Chan. The primary goal of Servlet 4 is to enable the fundamentally important changes in HTTP 2 for the entire server-side Java ecosystem. We wanted to talk to Ed about his Servlet 4 session at JavaOne 2014 and HTTP 2 generally: The details for the Servlet 4 session can be found here. Ed has several other key sessions on the track that we hope to talk to him about separately in the near future: What’s Next for JSF?: In this key session, Ed will be sharing the next steps for the continued evolution of the JSF specification in Java EE 8. Where’s My UI? The 2014 JavaOne Web App UI Smackdown: The UI space for web applications, especially in the Java ecosystem continues to be as hotly contested as ever. This is especially true with the (re)introduction of JavaScript based rich client frameworks like AngularJS. This lively panel brings together experts representing the diverse schools of thought for web UIs. Ed will be representing JSF of course. Neal Ford will moderate the panel as an independent and hopefully reasonably neutral party. Adopt-a-JSR for Java EE 7 and Java EE 8: Adopt-a-JSR has been a reasonable success for Java EE 7. With Java EE 8 we are planning to strengthen it far more as away of getting grassroots level participation in the specification efforts. This session will introduce Adopt-a-JSR, share how it worked for Java EE 7 and what we plan to do with it in Java EE 8. Ed will be sharing his perspectives on Adopt-a-JSR for both Java EE 7 and Java EE 8. Besides Ed's sessions, we have a very strong program for the Java EE track and JavaOne overall - just explore the content catalog. If you can't make it, you can be assured that we will make key content available after the conference just as we have always done.

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  • Annoying security "feature" in Windows 2008 R2 burns me, but not DVD's

    - by Stan Spotts
    This stuff drives me nuts. I'm all for hardening servers, and reducing security footprints, but I always want the option to allow me to get work done versus securing my system. I use Windows Server 2008 R2 as my laptop OS for a number of reasons I don't need to review here. It's pimped out to work like Windows 7 for most things. But my DVD writer is crippled, and evidently it's on purpose: http://blogs.technet.com/askcore/archive/2010/02/19/windows-server-2008-r2-no-recording-tab-for-cd-dvd-burner.aspx I don't WANT to log in as the local administrator to burn a damned DVD.  WTF isn't this configurable through the registry, or better yet, group policy? There are no security settings that I should not have the option to enable or disable.

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  • Brasero Burns Data, Not Time - or Piles of Discs

    <b>Linux Insider:</b> "There are a lot of CD/DVD burners for Linux out there, but Brasero stands out as a straightforward, easy-to-use, burner that has some nice extra features but won't make you relearn a lot of complex commands if you only use it occasionally. One nicety is the option to start a burn project and finish it much later, even if you're not using a rewritable disc."

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  • Windows-based video creation with Ken Burns effect

    - by Chris Farmer
    I want to create a video of old photos and I would like to use the Ken Burns effect for more pleasant transitions. I don't think I require inserting any existing video clips into this -- I just want to create a video from my images. It would be nice to be able to add titles and captions, too. Which Windows-based software can help me with this?

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  • app burns numbers into iPad screens, how can I prevent this?

    - by Andrew Johnson
    EDIT: My code for this is actually open source, if anyone would be able to look and comment. Things I can think of that might be an issue: using a custom font, using bright green, updating the label too fast? The repo is: https://github.com/andrewljohnson/StopWatch-of-Gaia The class for the time label: https://github.com/andrewljohnson/StopWatch-of-Gaia/blob/master/src/SWPTimeLabel.m The class that runs the timer to update the label: https://github.com/andrewljohnson/StopWatch-of-Gaia/blob/master/src/SWPViewController.m ============= My StopWatch app reportedly screen burns a number of iPads, for temporary periods. Does anyone have a suggestion about how I might prevent this screen persistence? Some known workaround to blank the pixels occasionally? I get emails all the time about it, and you can see numerous reviews here: http://itunes.apple.com/us/app/stopwatch+-timer-for-gym-kitchen/id518178439?mt=8 Apple can not advise me. I sent an email to appreview, and I was told to file a technical support request (DTS). When I filled the DTS, they told me it was not a code issue, and when I further asked for help from DTS, a "senior manager" told me that this was not an issue Apple knew about. He further advised me to file a bug with the Apple Radar bug tracker if I considered it to be a real issue. I filed the Radar bug a few weeks ago, but it has not been acknowledged. Updated radar link for Apple employees, per commenter's notes rdar://12173447

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  • More details on America's Cup use of Oracle Data Mining

    - by charlie.berger
    BMW Oracle Racing's America's Cup: A Victory for Database Technology BMW Oracle Racing's victory in the 33rd America's Cup yacht race in February showcased the crew's extraordinary sailing expertise. But to hear them talk, the real stars weren't actually human. "The story of this race is in the technology," says Ian Burns, design coordinator for BMW Oracle Racing. Gathering and Mining Sailing DataFrom the drag-resistant hull to its 23-story wing sail, the BMW Oracle USA trimaran is a technological marvel. But to learn to sail it well, the crew needed to review enormous amounts of reliable data every time they took the boat for a test run. Burns and his team collected performance data from 250 sensors throughout the trimaran at the rate of 10 times per second. An hour of sailing alone generates 90 million data points.BMW Oracle Racing turned to Oracle Data Mining in Oracle Database 11g to extract maximum value from the data. Burns and his team reviewed and shared raw data with crew members daily using a Web application built in Oracle Application Express (Oracle APEX). "Someone would say, 'Wouldn't it be great if we could look at some new combination of numbers?' We could quickly build an Oracle Application Express application and share the information during the same meeting," says Burns. Analyzing Wind and Other Environmental ConditionsBurns then streamed the data to the Oracle Austin Data Center, where a dedicated team tackled deeper analysis. Because the data was collected in an Oracle Database, the Data Center team could dive straight into the analytics problems without having to do any extract, transform, and load processes or data conversion. And the many advanced data mining algorithms in Oracle Data Mining allowed the analytics team to build vital performance analytics. For example, the technology team could remove masking elements such as environmental conditions to give accurate data on the best mast rotation for certain wind conditions. Without the data mining, Burns says the boat wouldn't have run as fast. "The design of the boat was important, but once you've got it designed, the whole race is down to how the guys can use it," he says. "With Oracle database technology we could compare the incremental improvements in our performance from the first day of sailing to the very last day. With data mining we could check data against the things we saw, and we could find things that weren't otherwise easily observable and findable."

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  • Session Report: What’s New in JSF: A Complete Tour of JSF 2.2

    - by Janice J. Heiss
    On Wednesday, Ed Burns, Consulting Staff Member at Oracle, presented a session, CON3870 -- “What’s New in JSF: A Complete Tour of JSF 2.2,” in which he provided an update on recent developments in JavaServer Faces 2.2. He began by emphasizing that, “JavaServer Faces 2.2 continues the evolution of the Java EE standard user interface technology. Like previous releases, this iteration is very community-driven and transparent.” He pointed out that since JSF was introduced at the 2001 JavaOne Keynote, it has had a long and successful run and has found a home in applications where the UI logic resides entirely on the server where the model and UI logic is. In such cases, the browser performs fairly simple functions. However, developers can take advantage of the power of browsers, something that Project Avatar is focused on by letting developers author their applications so the UI logic is running on the client and communicating to the back end via RESTful web services. “Most importantly,” remarked Burns, “JSF 2.2 offers a really good migration path because even in the scope of one application you could have an app written with JSF that has its UI logic on the server and, on a gradual basis, you could migrate parts of the app over to use client-side technologies. This can be done at any level of granularity – per page or per collection of pages. It all depends on what you want to do.” His presentation, which focused on the basic new features of JSF 2.2, began by restating the scope of JSF and encouraged attendees to check out Roger Kitain’s session: CON5133 “Techniques for Responsive Real-Time Web UIs.” Burns explained that JSF has endured because, “We still need web apps that are maintainable, localizable, quick to build, accessible, secure, look great and are fun to use.” It is used on every continent – the curious can go here to check out where its unofficial usage is tracked. He emphasized the significance of the UI logic being substantially on the server. This: Separates Component Semantics from Rendering, Allows components to “own” their little patch of the UI -- encode/decode, And offers a well-defined lifecycle: Inversion of Control. Burns reminded attendees that JSR-344, the spec for JSF 2.2, is now on Java Community Process 2.8, a revised version of the JCP that allows for more openness and transparency. He then offered some tools for community access to JSF 2.2:    * Public java.net projects spec http://jsf-spec.java.net/ impl http://jsf.java.net/ Open Source: GPL+Classpath Exception    * Mailing Lists [email protected]                                Public readable archive, JSPA signed member read/write [email protected]                                     Public readable archive, any java.net member read/write                         All mail sent to jsr344-experts is sent to users. * Issue Tracker spec http://jsf-spec.java.net/issues/ impl http://jsf.java.net/issues/ JSF 2.2, which is JSR 344, has a Public Review Draft planned by December 2012 with no need for a Renewal Ballot. The Early Draft Review of JSR 344 was published on December 8, 2011. Interested developers are encouraged to offer their input. Six Big Ticket Features of JSF 2.2 Burns summarized the six big ticket features of JSF 2.2:* HTML5 Friendly Markup Support Pass through attributes and elements * Faces Flows* Cross Site Request Forgery Protection* Loading Facelets via ResourceHandler* File Upload Component* Multi-Templating He explained that he called it “HTML 5 friendly” because there is really nothing HTML 5 specific about it -- it could be 4. But it enables developers to use new elements that are present in HTML5 without having a JSF component library that is written to take advantage of those specifically. It gives the page author the ability to use plain HTML5 to write their page, but to still take advantage of the server-side available in JSF. He presented a demo showing JSF 2.2’s ability to leverage the expressiveness of HTML5. Burns then explained the significance of face flows, which offer function points and quantify how much work has taken place, something of great value to JSF users. He went on to talk about JSF 2.2.’s cross-site request forgery protection (CSRF) and offered details about how it protects applications against attack. Then he talked about JSF 2.2’s File Upload Component and explained that the final specification will have Ajax and non-Ajax support. The current milestone has non-Ajax support implemented. He then went on to explain its capacity to add facelets through ResourceHandler. Previously, JSF 2.0 added Facelets and ResourceHandler as disparate units; now in JSF 2.2 the two concepts are unified. Finally, he explained the concept of multi-templating in JSF 2.2 and went on to discuss more medium-level features of the release. For an easy, low maintenance way of staying in touch with JSF developments go to JSF’s Twitter page where every month or so, important updates are offered.

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  • jQuery UI blind effect - reveal from bottom

    - by ronnie burns
    This could be really obvious and I'm completely missing it. I've searched for hours and can't seem to find a way to, using jQuery, reveal a hidden div from the bottom up. What I am trying to achieve is exactly as in the following link, but in reverse: http://jqueryui.com/demos/show/ I can slide a div from the bottom to the top, but this reveals itself as it moves, rather than being 'masked' in. Like I said, this could (should?) be really obvious and I'm not seeing it, but I've been looking for ages and can't find a solution to this relatively simple problem. Thanks, Ronnie

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  • OpenJDK DIO Project Now Live! Java SE Embedded API Accessing Peripherals

    - by hinkmond
    The DIO project on OpenJDK is now live! For those who grew up in the 1970's and 1980's, you might remember Ronnie James Dio, lead singer of Black Sabbath after Ozzy was fired, and lead singer of his own band, Dio. Well, this DIO is not that Dio. This DIO is the OpenJDK Device I/O project which provides a Java-level API for accessing generic device peripherals on embedded devices, like your Raspberry Pi running Java SE Embedded software. See: OpenJDK DIO Project Here's a quote: + General Purpose Input/Output (GPIO) + Inter-Integrated Circuit Bus (I2C) + Universal Asynchronous Receiver/Transmitter (UART) + Serial Peripheral Interface If you're familiar with Pi4J, then you're going to like DIO. And, if you liked Ozzy, you probably liked Ronnie James Dio. This will probably make Robert Savage happy too. The part about DIO being live now, not the part about Dio replacing Ozzy, because everyone likes Ozzy. Hinkmond

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  • Validating a linked item&rsquo;s data template in Sitecore

    - by Kyle Burns
    I’ve been doing quite a bit of work in Sitecore recently and last week I encountered a situation that it appears many others have hit.  I was working with a field that had been configured originally as a grouped droplink, but now needed to be updated to support additional levels of hierarchy in the folder structure.  If you’ve done any work in Sitecore that statement makes sense, but if not it may seem a bit cryptic.  Sitecore offers a number of different field types and a subset of these field types focus on providing links either to other items on the content tree or to content that is not stored in Sitecore.  In the case of the grouped droplink, the field is configured with a “root” folder and each direct descendant of this folder is considered to be a header for a grouping of other items and displayed in a dropdown.  A picture is worth a thousand words, so consider the following piece of a content tree: If I configure a grouped droplink field to use the “Current” folder as its datasource, the control that gets to my content author looks like this: This presents a nicely organized display and limits the user to selecting only the direct grandchildren of the folder root.  It also presents the limitation that struck as we were thinking through the content architecture and how it would hold up over time – the authors cannot further organize content under the root folder because of the structure required for the dropdown to work.  Over time, not allowing the hierarchy to go any deeper would prevent out authors from being able to organize their content in a way that it would be found when needed, so the grouped droplink data type was not going to fit the bill. I needed to look for an alternative data type that allowed for selection of a single item and limited my choices to descendants of a specific node on the content tree.  After looking at the options available for links in Sitecore and considering them against each other, one option stood out as nearly perfect – the droptree.  This field type stores its data identically to the droplink and allows for the selection of zero or one items under a specific node in the content tree.  By changing my data template to use droptree instead of grouped droplink, the author is now presented with the following when selecting a linked item: Sounds great, but a did say almost perfect – there’s still one flaw.  The code intended to display the linked item is expecting the selection to use a specific data template (or more precisely it makes certain assumptions about the fields that will be present), but the droptree does nothing to prevent the author from selecting a folder (since folders are items too) instead of one of the items contained within a folder.  I looked to see if anyone had already solved this problem.  I found many people discussing the problem, but the closest that I found to a solution was the statement “the best thing would probably be to create a custom validator” with no further discussion in regards to what this validator might look like.  I needed to create my own validator to ensure that the user had not selected a folder.  Since so many people had the same issue, I decided to make the validator as reusable as possible and share it here. The validator that I created inherits from StandardValidator.  In order to make the validator more intuitive to developers that are familiar with the TreeList controls in Sitecore, I chose to implement the following parameters: ExcludeTemplatesForSelection – serves as a “deny list”.  If the data template of the selected item is in this list it will not validate IncludeTemplatesForSelection – this can either be empty to indicate that any template not contained in the exclusion list is acceptable or it can contain the list of acceptable templates Now that I’ve explained the parameters and the purpose of the validator, I’ll let the code do the rest of the talking: 1: /// <summary> 2: /// Validates that a link field value meets template requirements 3: /// specified using the following parameters: 4: /// - ExcludeTemplatesForSelection: If present, the item being 5: /// based on an excluded template will cause validation to fail. 6: /// - IncludeTemplatesForSelection: If present, the item not being 7: /// based on an included template will cause validation to fail 8: /// 9: /// ExcludeTemplatesForSelection trumps IncludeTemplatesForSelection 10: /// if the same value appears in both lists. Lists are comma seperated 11: /// </summary> 12: [Serializable] 13: public class LinkItemTemplateValidator : StandardValidator 14: { 15: public LinkItemTemplateValidator() 16: { 17: } 18:   19: /// <summary> 20: /// Serialization constructor is required by the runtime 21: /// </summary> 22: /// <param name="info"></param> 23: /// <param name="context"></param> 24: public LinkItemTemplateValidator(SerializationInfo info, StreamingContext context) : base(info, context) { } 25:   26: /// <summary> 27: /// Returns whether the linked item meets the template 28: /// constraints specified in the parameters 29: /// </summary> 30: /// <returns> 31: /// The result of the evaluation. 32: /// </returns> 33: protected override ValidatorResult Evaluate() 34: { 35: if (string.IsNullOrWhiteSpace(ControlValidationValue)) 36: { 37: return ValidatorResult.Valid; // let "required" validation handle 38: } 39:   40: var excludeString = Parameters["ExcludeTemplatesForSelection"]; 41: var includeString = Parameters["IncludeTemplatesForSelection"]; 42: if (string.IsNullOrWhiteSpace(excludeString) && string.IsNullOrWhiteSpace(includeString)) 43: { 44: return ValidatorResult.Valid; // "allow anything" if no params 45: } 46:   47: Guid linkedItemGuid; 48: if (!Guid.TryParse(ControlValidationValue, out linkedItemGuid)) 49: { 50: return ValidatorResult.Valid; // probably put validator on wrong field 51: } 52:   53: var item = GetItem(); 54: var linkedItem = item.Database.GetItem(new ID(linkedItemGuid)); 55:   56: if (linkedItem == null) 57: { 58: return ValidatorResult.Valid; // this validator isn't for broken links 59: } 60:   61: var exclusionList = (excludeString ?? string.Empty).Split(','); 62: var inclusionList = (includeString ?? string.Empty).Split(','); 63:   64: if ((inclusionList.Length == 0 || inclusionList.Contains(linkedItem.TemplateName)) 65: && !exclusionList.Contains(linkedItem.TemplateName)) 66: { 67: return ValidatorResult.Valid; 68: } 69:   70: Text = GetText("The field \"{0}\" specifies an item which is based on template \"{1}\". This template is not valid for selection", GetFieldDisplayName(), linkedItem.TemplateName); 71:   72: return GetFailedResult(ValidatorResult.FatalError); 73: } 74:   75: protected override ValidatorResult GetMaxValidatorResult() 76: { 77: return ValidatorResult.FatalError; 78: } 79:   80: public override string Name 81: { 82: get { return @"LinkItemTemplateValidator"; } 83: } 84: }   In this blog entry, I have shared some code that I found useful in solving a problem that seemed fairly common.  Hopefully the next person that is looking for this answer finds it useful as well.

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  • Screen shots and documentation on the cheap

    - by Kyle Burns
    Occasionally I am surprised to open up my toolbox and find a great tool that I've had for years and never noticed.  The other day I had just such an experience with Windows Server 2008.  A co-worker of mine was squinting to read to screenshots that he had taken using the "Print Screen, paste" method in WordPad and asked me if there was a better tool available at a reasonable cost.  My first instinct was to take a look at CamStudio for him, but I also knew that he had an immediate need to take some more screenshots, so I decided to check and see if the Snipping Tool found in Windows 7 is also available in Windows Server 2008.  I clicked the Start button and typed “snip” into the search bar and while the Snipping Tool did not come up, a Control Panel item labeled “Record steps to reproduce a problem” did. The application behind the Control Panel entry was “Problem Steps Recorder” (PSR.exe) and I have confirmed that it is available in Windows 7 and Windows Server 2008 R2 but have not checked other platforms.  It presents a pretty minimal and intuitive interface in providing a “Start Record”, “Stop Record”, and “Add Comment” button.  The “Start Record” button shockingly starts recording and, sure enough, the “Stop Record” button stops recording.  The “Add Comment” button prompts for a comment and for you to highlight the area of the screen to which your comment is related.  Once you’re done recording, the tool outputs an MHT file packaged in a ZIP archive.  This file contains a series of screen shots depicting the user’s interactions and giving timestamps and descriptive text (such as “User left click on “Test” in “My Page – Windows Internet Explorer”) as well as the comments they made along the way and some diagnostics about the applications captured. The Problem Steps Recorder looks like a simple solution to the most common of my needs for documentation that can turn “I can’t understand how to make it do what you’re reporting” to “Oh, I see what you’re talking about and will fix it right away”.  I you’re like me and haven’t yet discovered this tool give it a whirl and see for yourself.

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  • Using Sitecore RenderingContext Parameters as MVC controller action arguments

    - by Kyle Burns
    I have been working with the Technical Preview of Sitecore 6.6 on a project and have been for the most part happy with the way that Sitecore (which truly is an MVC implementation unto itself) has been expanded to support ASP.NET MVC. That said, getting up to speed with the combined platform has not been entirely without stumbles and today I want to share one area where Sitecore could have really made things shine from the "it just works" perspective. A couple days ago I was asked by a colleague about the usage of the "Parameters" field that is defined on Sitecore's Controller Rendering data template. Based on the standard way that Sitecore handles a field named Parameters, I was able to deduce that the field expected key/value pairs separated by the "&" character, but beyond that I wasn't sure and didn't see anything from a documentation perspective to guide me, so it was time to dig and find out where the data in the field was made available. My first thought was that it would be really nice if Sitecore handled the parameters in this field consistently with the way that ASP.NET MVC handles the various parameter collections on the HttpRequest object and automatically maps them to parameters of the action method executing. Being the hopeful sort, I configured a name/value pair on one of my renderings, added a parameter with matching name to the controller action and fired up the bugger to see... that the parameter was not populated. Having established that the field's value was not going to be presented to me the way that I had hoped it would, the next assumption that I would work on was that Sitecore would handle this field similar to how they handle other similar data and would plug it into some ambient object that I could reference from within the controller method. After a considerable amount of guessing, testing, and cracking code open with Redgate's Reflector (a must-have companion to Sitecore documentation), I found that the most direct way to access the parameter was through the ambient RenderingContext object using code similar to: string myArgument = string.Empty; var rc = Sitecore.Mvc.Presentation.RenderingContext.CurrentOrNull; if (rc != null) {     var parms = rc.Rendering.Parameters;     myArgument = parms["myArgument"]; } At this point, we know how this field is used out of the box from Sitecore and can provide information from Sitecore's Content Editor that will be available when the controller action is executing, but it feels a little dirty. In order to properly test the action method I would have to do a lot of setup work and possible use an isolation framework such as Pex and Moles to get at a value that my action method is dependent upon. Notice I said that my method is dependent upon the value but in order to meet that dependency I've accepted another dependency upon Sitecore's RenderingContext.  I'm a big believer in, when possible, ensuring that any piece of code explicitly advertises dependencies using the method signature, so I found myself still wanting this to work the same as if the parameters were in the request route, querystring, or form by being able to add a myArgument parameter to the action method and have this parameter populated by the framework. Lucky for us, the ASP.NET MVC framework is extremely flexible and provides some easy to grok and use extensibility points. ASP.NET MVC is able to provide information from the request as input parameters to controller actions because it uses objects which implement an interface called IValueProvider and have been registered to service the application. The most basic statement of responsibility for an IValueProvider implementation is "I know about some data which is indexed by key. If you hand me the key for a piece of data that I know about I give you that data". When preparing to invoke a controller action, the framework queries registered IValueProvider implementations with the name of each method argument to see if the ValueProvider can supply a value for the parameter. (the rest of this post will assume you're working along and make a lot more sense if you do) Let's pull Sitecore out of the equation for a second to simplify things and create an extremely simple IValueProvider implementation. For this example, I first create a new ASP.NET MVC3 project in Visual Studio, selecting "Internet Application" and otherwise taking defaults (I'm assuming that anyone reading this far in the post either already knows how to do this or will need to take a quick run through one of the many available basic MVC tutorials such as the MVC Music Store). Once the new project is created, go to the Index action of HomeController.  This action sets a Message property on the ViewBag to "Welcome to ASP.NET MVC!" and invokes the View, which has been coded to display the Message. For our example, we will remove the hard coded message from this controller (although we'll leave it just as hard coded somewhere else - this is sample code). For the first step in our exercise, add a string parameter to the Index action method called welcomeMessage and use the value of this argument to set the ViewBag.Message property. The updated Index action should look like: public ActionResult Index(string welcomeMessage) {     ViewBag.Message = welcomeMessage;     return View(); } This represents the entirety of the change that you will make to either the controller or view.  If you run the application now, the home page will display and no message will be presented to the user because no value was supplied to the Action method. Let's now write a ValueProvider to ensure this parameter gets populated. We'll start by creating a new class called StaticValueProvider. When the class is created, we'll update the using statements to ensure that they include the following: using System.Collections.Specialized; using System.Globalization; using System.Web.Mvc; With the appropriate using statements in place, we'll update the StaticValueProvider class to implement the IValueProvider interface. The System.Web.Mvc library already contains a pretty flexible dictionary-like implementation called NameValueCollectionValueProvider, so we'll just wrap that and let it do most of the real work for us. The completed class looks like: public class StaticValueProvider : IValueProvider {     private NameValueCollectionValueProvider _wrappedProvider;     public StaticValueProvider(ControllerContext controllerContext)     {         var parameters = new NameValueCollection();         parameters.Add("welcomeMessage", "Hello from the value provider!");         _wrappedProvider = new NameValueCollectionValueProvider(parameters, CultureInfo.InvariantCulture);     }     public bool ContainsPrefix(string prefix)     {         return _wrappedProvider.ContainsPrefix(prefix);     }     public ValueProviderResult GetValue(string key)     {         return _wrappedProvider.GetValue(key);     } } Notice that the only entry in the collection matches the name of the argument to our HomeController's Index action.  This is the important "secret sauce" that will make things work. We've got our new value provider now, but that's not quite enough to be finished. Mvc obtains IValueProvider instances using factories that are registered when the application starts up. These factories extend the abstract ValueProviderFactory class by initializing and returning the appropriate implementation of IValueProvider from the GetValueProvider method. While I wouldn't do so in production code, for the sake of this example, I'm going to add the following class definition within the StaticValueProvider.cs source file: public class StaticValueProviderFactory : ValueProviderFactory {     public override IValueProvider GetValueProvider(ControllerContext controllerContext)     {         return new StaticValueProvider(controllerContext);     } } Now that we have a factory, we can register it by adding the following line to the end of the Application_Start method in Global.asax.cs: ValueProviderFactories.Factories.Add(new StaticValueProviderFactory()); If you've done everything right to this point, you should be able to run the application and be presented with the home page reading "Hello from the value provider!". Now that you have the basics of the IValueProvider down, you have everything you need to enhance your Sitecore MVC implementation by adding an IValueProvider that exposes values from the ambient RenderingContext's Parameters property. I'll provide the code for the IValueProvider implementation (which should look VERY familiar) and you can use the work we've already done as a reference to create and register the factory: public class RenderingContextValueProvider : IValueProvider {     private NameValueCollectionValueProvider _wrappedProvider = null;     public RenderingContextValueProvider(ControllerContext controllerContext)     {         var collection = new NameValueCollection();         var rc = RenderingContext.CurrentOrNull;         if (rc != null && rc.Rendering != null)         {             foreach(var parameter in rc.Rendering.Parameters)             {                 collection.Add(parameter.Key, parameter.Value);             }         }         _wrappedProvider = new NameValueCollectionValueProvider(collection, CultureInfo.InvariantCulture);         }     public bool ContainsPrefix(string prefix)     {         return _wrappedProvider.ContainsPrefix(prefix);     }     public ValueProviderResult GetValue(string key)     {         return _wrappedProvider.GetValue(key);     } } In this post I've discussed the MVC IValueProvider used to map data to controller action method arguments and how this can be integrated into your Sitecore 6.6 MVC solution.

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  • Build Dependencies and Silverlight 4

    - by Kyle Burns
    At my current position, I’ve been doing quite a bit of Silverlight development and have also been working with TFS2010 build services to enable continuous integration.  One of the critical pieces of a successful continuous build setup (and also one of the benefits of having one) is that the build system should be able to “get latest” against the source repository and immediately build with no errors.  This can break down both in an automated build scenario and a “new guy” scenario when the solution has external dependencies that may not be present in the build environment. The method that I use to address the dependency issue is to store all of the binaries upon which my solution depends in a folder under the solution root called “Reference Items”.  I keep this folder as part of the solution and check all of the binaries into source control so when I get the latest version of the solution from source control all of the binaries are downloaded to my machine as well and gets me closer to the ideal where a new developer installs the development IDE, get latest and can immediately build and run unit tests before jumping into coding the feature of the day. This all sounds pretty good (and it is), but a little while back I ran into one of those little hiccups that requires a little manual intervention.  The issue that I ran into is that with Silverlight (at least version 4), the behavior of the “Add Reference” command when adding reference to a DLL that is present in the GAC is to omit the HintPath element that it includes with regular .Net projects, so even if the DLL is setting in the Reference Items folder and downloaded to the build machine it cannot be found at compile time and the build will fail. To work around this behavior, you need to be comfortable editing the XML project files generated by Visual Studio (in my case this is typically a .csproj file).  Simply open the project file in your favorite text editor, find the Reference element that refers to the component, and modify the XML to include the HintPath.  Here’s a before and after example of the component that ultimately led me to the investigation behind this post: Before: <Reference Include="Telerik.Windows.Controls, Version=2011.2.920.1040, Culture=neutral, PublicKeyToken=5803cfa389c90ce7, processorArchitecture=MSIL" /> After: <Reference Include="Telerik.Windows.Controls, Version=2011.2.920.1040, Culture=neutral, PublicKeyToken=5803cfa389c90ce7, processorArchitecture=MSIL">       <HintPath>..\Reference Items\Telerik.Windows.Controls.dll</HintPath>     </Reference>

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  • Cant access ephemeral storage on Amazon ubuntu instance

    - by matt burns
    I want to utilise my ephemeral storage as mentioned in this question but I seem to be falling at the first hurdle. I can't even see /mnt: ~$ df -ah Filesystem Size Used Avail Use% Mounted on /dev/xvda1 8.0G 855M 6.8G 12% / proc 0 0 0 - /proc sysfs 0 0 0 - /sys none 0 0 0 - /sys/fs/fuse/connections none 0 0 0 - /sys/kernel/debug none 0 0 0 - /sys/kernel/security udev 288M 8.0K 288M 1% /dev devpts 0 0 0 - /dev/pts tmpfs 119M 152K 118M 1% /run none 5.0M 0 5.0M 0% /run/lock none 296M 0 296M 0% /run/shm This is from a vanilla instance of an ubuntu AMI (12.04-amd64-server-20120424 ami-a29943cb) I'm not bothered about resizing the partition, I just want to be able to use the space for writing temp files.

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  • When is my View too smart?

    - by Kyle Burns
    In this posting, I will discuss the motivation behind keeping View code as thin as possible when using patterns such as MVC, MVVM, and MVP.  Once the motivation is identified, I will examine some ways to determine whether a View contains logic that belongs in another part of the application.  While the concepts that I will discuss are applicable to most any pattern which favors a thin View, any concrete examples that I present will center on ASP.NET MVC. Design patterns that include a Model, a View, and other components such as a Controller, ViewModel, or Presenter are not new to application development.  These patterns have, in fact, been around since the early days of building applications with graphical interfaces.  The reason that these patterns emerged is simple – the code running closest to the user tends to be littered with logic and library calls that center around implementation details of showing and manipulating user interface widgets and when this type of code is interspersed with application domain logic it becomes difficult to understand and much more difficult to adequately test.  By removing domain logic from the View, we ensure that the View has a single responsibility of drawing the screen which, in turn, makes our application easier to understand and maintain. I was recently asked to take a look at an ASP.NET MVC View because the developer reviewing it thought that it possibly had too much going on in the view.  I looked at the .CSHTML file and the first thing that occurred to me was that it began with 40 lines of code declaring member variables and performing the necessary calculations to populate these variables, which were later either output directly to the page or used to control some conditional rendering action (such as adding a class name to an HTML element or not rendering another element at all).  This exhibited both of what I consider the primary heuristics (or code smells) indicating that the View is too smart: Member variables – in general, variables in View code are an indication that the Model to which the View is being bound is not sufficient for the needs of the View and that the View has had to augment that Model.  Notable exceptions to this guideline include variables used to hold information specifically related to rendering (such as a dynamically determined CSS class name or the depth within a recursive structure for indentation purposes) and variables which are used to facilitate looping through collections while binding. Arithmetic – as with member variables, the presence of arithmetic operators within View code are an indication that the Model servicing the View is insufficient for its needs.  For example, if the Model represents a line item in a sales order, it might seem perfectly natural to “normalize” the Model by storing the quantity and unit price in the Model and multiply these within the View to show the line total.  While this does seem natural, it introduces a business rule to the View code and makes it impossible to test that the rounding of the result meets the requirement of the business without executing the View.  Within View code, arithmetic should only be used for activities such as incrementing loop counters and calculating element widths. In addition to the two characteristics of a “Smart View” that I’ve discussed already, this View also exhibited another heuristic that commonly indicates to me the need to refactor a View and make it a bit less smart.  That characteristic is the existence of Boolean logic that either does not work directly with properties of the Model or works with too many properties of the Model.  Consider the following code and consider how logic that does not work directly with properties of the Model is just another form of the “member variable” heuristic covered earlier: @if(DateTime.Now.Hour < 12) {     <div>Good Morning!</div> } else {     <div>Greetings</div> } This code performs business logic to determine whether it is morning.  A possible refactoring would be to add an IsMorning property to the Model, but in this particular case there is enough similarity between the branches that the entire branching structure could be collapsed by adding a Greeting property to the Model and using it similarly to the following: <div>@Model.Greeting</div> Now let’s look at some complex logic around multiple Model properties: @if (ModelPageNumber + Model.NumbersToDisplay == Model.PageCount         || (Model.PageCount != Model.CurrentPage             && !Model.DisplayValues.Contains(Model.PageCount))) {     <div>There's more to see!</div> } In this scenario, not only is the View code difficult to read (you shouldn’t have to play “human compiler” to determine the purpose of the code), but it also complex enough to be at risk for logical errors that cannot be detected without executing the View.  Conditional logic that requires more than a single logical operator should be looked at more closely to determine whether the condition should be evaluated elsewhere and exposed as a single property of the Model.  Moving the logic above outside of the View and exposing a new Model property would simplify the View code to: @if(Model.HasMoreToSee) {     <div>There’s more to see!</div> } In this posting I have briefly discussed some of the more prominent heuristics that indicate a need to push code from the View into other pieces of the application.  You should now be able to recognize these symptoms when building or maintaining Views (or the Models that support them) in your applications.

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  • Why do we (really) program to interfaces?

    - by Kyle Burns
    One of the earliest lessons I was taught in Enterprise development was "always program against an interface".  This was back in the VB6 days and I quickly learned that no code would be allowed to move to the QA server unless my business objects and data access objects each are defined as an interface and have a matching implementation class.  Why?  "It's more reusable" was one answer.  "It doesn't tie you to a specific implementation" a slightly more knowing answer.  And let's not forget the discussion ending "it's a standard".  The problem with these responses was that senior people didn't really understand the reason we were doing the things we were doing and because of that, we were entirely unable to realize the intent behind the practice - we simply used interfaces and had a bunch of extra code to maintain to show for it. It wasn't until a few years later that I finally heard the term "Inversion of Control".  Simply put, "Inversion of Control" takes the creation of objects that used to be within the control (and therefore a responsibility of) of your component and moves it to some outside force.  For example, consider the following code which follows the old "always program against an interface" rule in the manner of many corporate development shops: 1: ICatalog catalog = new Catalog(); 2: Category[] categories = catalog.GetCategories(); In this example, I met the requirement of the rule by declaring the variable as ICatalog, but I didn't hit "it doesn't tie you to a specific implementation" because I explicitly created an instance of the concrete Catalog object.  If I want to test the functionality of the code I just wrote I have to have an environment in which Catalog can be created along with any of the resources upon which it depends (e.g. configuration files, database connections, etc) in order to test my functionality.  That's a lot of setup work and one of the things that I think ultimately discourages real buy-in of unit testing in many development shops. So how do I test my code without needing Catalog to work?  A very primitive approach I've seen is to change the line the instantiates catalog to read: 1: ICatalog catalog = new FakeCatalog();   once the test is run and passes, the code is switched back to the real thing.  This obviously poses a huge risk for introducing test code into production and in my opinion is worse than just keeping the dependency and its associated setup work.  Another popular approach is to make use of Factory methods which use an object whose "job" is to know how to obtain a valid instance of the object.  Using this approach, the code may look something like this: 1: ICatalog catalog = CatalogFactory.GetCatalog();   The code inside the factory is responsible for deciding "what kind" of catalog is needed.  This is a far better approach than the previous one, but it does make projects grow considerably because now in addition to the interface, the real implementation, and the fake implementation(s) for testing you have added a minimum of one factory (or at least a factory method) for each of your interfaces.  Once again, developers say "that's too complicated and has me writing a bunch of useless code" and quietly slip back into just creating a new Catalog and chalking any test failures up to "it will probably work on the server". This is where software intended specifically to facilitate Inversion of Control comes into play.  There are many libraries that take on the Inversion of Control responsibilities in .Net and most of them have many pros and cons.  From this point forward I'll discuss concepts from the standpoint of the Unity framework produced by Microsoft's Patterns and Practices team.  I'm primarily focusing on this library because it questions about it inspired this posting. At Unity's core and that of most any IoC framework is a catalog or registry of components.  This registry can be configured either through code or using the application's configuration file and in the most simple terms says "interface X maps to concrete implementation Y".  It can get much more complicated, but I want to keep things at the "what does it do" level instead of "how does it do it".  The object that exposes most of the Unity functionality is the UnityContainer.  This object exposes methods to configure the catalog as well as the Resolve<T> method which is used to obtain an instance of the type represented by T.  When using the Resolve<T> method, Unity does not necessarily have to just "new up" the requested object, but also can track dependencies of that object and ensure that the entire dependency chain is satisfied. There are three basic ways that I have seen Unity used within projects.  Those are through classes directly using the Unity container, classes requiring injection of dependencies, and classes making use of the Service Locator pattern. The first usage of Unity is when classes are aware of the Unity container and directly call its Resolve method whenever they need the services advertised by an interface.  The up side of this approach is that IoC is utilized, but the down side is that every class has to be aware that Unity is being used and tied directly to that implementation. Many developers don't like the idea of as close a tie to specific IoC implementation as is represented by using Unity within all of your classes and for the most part I agree that this isn't a good idea.  As an alternative, classes can be designed for Dependency Injection.  Dependency Injection is where a force outside the class itself manipulates the object to provide implementations of the interfaces that the class needs to interact with the outside world.  This is typically done either through constructor injection where the object has a constructor that accepts an instance of each interface it requires or through property setters accepting the service providers.  When using dependency, I lean toward the use of constructor injection because I view the constructor as being a much better way to "discover" what is required for the instance to be ready for use.  During resolution, Unity looks for an injection constructor and will attempt to resolve instances of each interface required by the constructor, throwing an exception of unable to meet the advertised needs of the class.  The up side of this approach is that the needs of the class are very clearly advertised and the class is unaware of which IoC container (if any) is being used.  The down side of this approach is that you're required to maintain the objects passed to the constructor as instance variables throughout the life of your object and that objects which coordinate with many external services require a lot of additional constructor arguments (this gets ugly and may indicate a need for refactoring). The final way that I've seen and used Unity is to make use of the ServiceLocator pattern, of which the Patterns and Practices team has also provided a Unity-compatible implementation.  When using the ServiceLocator, your class calls ServiceLocator.Retrieve in places where it would have called Resolve on the Unity container.  Like using Unity directly, it does tie you directly to the ServiceLocator implementation and makes your code aware that dependency injection is taking place, but it does have the up side of giving you the freedom to swap out the underlying IoC container if necessary.  I'm not hugely concerned with hiding IoC entirely from the class (I view this as a "nice to have"), so the single biggest problem that I see with the ServiceLocator approach is that it provides no way to proactively advertise needs in the way that constructor injection does, allowing more opportunity for difficult to track runtime errors. This blog entry has not been intended in any way to be a definitive work on IoC, but rather as something to spur thought about why we program to interfaces and some ways to reach the intended value of the practice instead of having it just complicate your code.  I hope that it helps somebody begin or continue a journey away from being a "Cargo Cult Programmer".

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  • Stop trying to be perfect

    - by Kyle Burns
    Yes, Bob is my uncle too.  I also think the points in the Manifesto for Software Craftsmanship (manifesto.softwarecraftsmanship.org) are all great.  What amazes me is that tend to confuse the term “well crafted” with “perfect”.  I'm about to say something that will make Quality Assurance managers and many development types as well until you think about it as a craftsman – “Stop trying to be perfect”. Now let me explain what I mean.  Building software, as with building almost anything, often involves a series of trade-offs where either one undesired characteristic is accepted as necessary to achieve another desired one (or maybe stave off one that is even less desirable) or a desirable characteristic is sacrificed for the same reasons.  This implies that perfection itself is unattainable.  What is attainable is “sufficient” and I think that this really goes to the heart both of what people are trying to do with Agile and with the craftsmanship movement.  Simply put, sufficient software drives the greatest business value.   I've been in many meetings where “how can we keep anything from ever going wrong” has become the thing that holds us in analysis paralysis.  I've also been the guy trying way too hard to perfect some function to make sure that every edge case is accounted for.  Somewhere in there, something a drill instructor said while I was in boot camp occurred to me.  In response to being asked a question by another recruit having to do with some edge case (I can barely remember the context), he said “What if grasshoppers had machine guns?  Would the birds still **** with them?”  It sounds funny, but there's a lot of wisdom in those words.   “Sufficient” is different for every situation and it’s important to understand what sufficient means in the context of the work you’re doing.  If I’m writing a timesheet application (and please shoot me if I am), I’m going to have a much higher tolerance for imperfection than if you’re writing software to control life support systems on spacecraft.  I’m also likely to have less need for high volume performance than if you’re writing software to control stock trading transactions.   I’d encourage anyone who has read this far to instead of trying to be perfect, try to create software that is sufficient in every way.  If you’re working to make a component that is sufficient “better”, ask yourself if there is any component left that is not yet sufficient.  If the answer is “yes” you’re working on the wrong thing and need to adjust.  If the answer is “no”, why aren’t you shipping and delivering business value?

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  • Obtaining positional information in the IEnumerable Select extension method

    - by Kyle Burns
    This blog entry is intended to provide a narrow and brief look into a way to use the Select extension method that I had until recently overlooked. Every developer who is using IEnumerable extension methods to work with data has been exposed to the Select extension method, because it is a pretty critical piece of almost every query over a collection of objects.  The method is defined on type IEnumerable and takes as its argument a function that accepts an item from the collection and returns an object which will be an item within the returned collection.  This allows you to perform transformations on the source collection.  A somewhat contrived example would be the following code that transforms a collection of strings into a collection of anonymous objects: 1: var media = new[] {"book", "cd", "tape"}; 2: var transformed = media.Select( item => 3: { 4: Media = item 5: } ); This code transforms the array of strings into a collection of objects which each have a string property called Media. If every developer using the LINQ extension methods already knows this, why am I blogging about it?  I’m blogging about it because the method has another overload that I hadn’t seen before I needed it a few weeks back and I thought I would share a little about it with whoever happens upon my blog.  In the other overload, the function defined in the first overload as: 1: Func<TSource, TResult> is instead defined as: 1: Func<TSource, int, TResult>   The additional parameter is an integer representing the current element’s position in the enumerable sequence.  I used this information in what I thought was a pretty cool way to compare collections and I’ll probably blog about that sometime in the near future, but for now we’ll continue with the contrived example I’ve already started to keep things simple and show how this works.  The following code sample shows how the positional information could be used in an alternating color scenario.  I’m using a foreach loop because IEnumerable doesn’t have a ForEach extension, but many libraries do add the ForEach extension to IEnumerable so you can update the code if you’re using one of these libraries or have created your own. 1: var media = new[] {"book", "cd", "tape"}; 2: foreach (var result in media.Select( 3: (item, index) => 4: new { Item = item, Index = index })) 5: { 6: Console.ForegroundColor = result.Index % 2 == 0 7: ? ConsoleColor.Blue : ConsoleColor.Yellow; 8: Console.WriteLine(result.Item); 9: }

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  • How do I start my career on a 3-year-old degree [on hold]

    - by Gabriel Burns
    I received my bachelor's degree in Com S (second major in math) in December 2011. I didn't have the best GPA (I was excellent at programming projects and had a deep understanding of CS concepts, but school is generally not the best format for displaying my strengths), and my only internship was with a now-defunct startup. After graduation I applied for several jobs, had a fair number of interviews, but never got hired. After a while, I got somewhat discouraged, and though I still said I was looking, and occasionally applied for something, my pace slowed down considerably. I remain convinced that software development is the right path for me, and that I could make a real contribution to someones work force, but I'm at a loss as to how I can convince anyone of this. My major problems are as follows. Lack of professional experience-- a problem for every entry-level programmer, I suppose, but everyone seems to want someone with a couple of years under their belt. Rustiness-- I've not really done any programming in about a year, and since school all I've really done is various programming competitions and puzzles. (codechef, hackerrank, etc.) I need a way to sharpen my skills. Long term unemployment-- while I had a basic fast-food job after I graduated, I've been truly unemployed for about a year now. Furthermore, no one has ever hired me as a programmer, and any potential employer is liable to wonder why. Old References-- my references are all college professors and one supervisor from my internship, none of whom I've had any contact with since I graduated. Confidence-- I have no doubt that I could be a good professional programmer, and make just about any employer glad that they hired me, but I'm aware of my red flags as a candidate, and have a hard time heading confidently into an interview. How can I overcome these problems and keep my career from being over before it starts?

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  • Where's the source code?

    - by Kyle Burns
    I've been contacted by several people through this blog asking about the missing source code for the "Beginning Windows 8 Application Development - XAML Edition" book (the book is available at http://www.amazon.com/gp/product/1430245662/http://www.amazon.com/gp/product/1430245662/) and wanted to share this with others who may have come to this blog looking for it but may not have communicated with me.  The publisher (Apress) does know that the source code is not posted on the book's product page and will be correcting it.  Apress is located in New York City and things were slowed down a little bit last week due to the storm, but I've been assured they will be correcting the product page as soon as they can.  Thanks to everyone who has bought the book and I especially appreciate your patience.

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  • Varnish 3.0.2 to Apache2 sometimes return error 503

    - by Ronnie Jespersen
    Hey guys I hope you can help me out here. I have an Ngingx parsing http and https to a varnish cache(3.0.2). From the varnish it is sent to apache2. Now I have for some time been tracking some strange 503 errors. But I cant seem to find the silver bullet. Currently I am logging the 503 errors through varnish this way: sudo varnishlog -c -m TxStatus:503 >> /home/rj/varnishlog503.log and then referring to the apache access log to see if any 503 requests have been handled. Today I had a health check from the firewall that failed: 20 SessionOpen c 127.0.0.1 34319 :8081 20 ReqStart c 127.0.0.1 34319 607335635 20 RxRequest c HEAD 20 RxURL c /health-check 20 RxProtocol c HTTP/1.0 20 RxHeader c X-Real-IP: 192.168.3.254 20 RxHeader c Host: 192.168.3.189 20 RxHeader c X-Forwarded-For: 192.168.3.254 20 RxHeader c Connection: close 20 RxHeader c User-Agent: Astaro Service Monitor 0.9 20 RxHeader c Accept: */* 20 VCL_call c recv lookup 20 VCL_call c hash 20 Hash c /health-check 20 VCL_return c hash 20 VCL_call c miss fetch 20 Backend c 33 aurum aurum 20 FetchError c http first read error: -1 11 (No error recorded) 20 VCL_call c error deliver 20 VCL_call c deliver deliver 20 TxProtocol c HTTP/1.1 20 TxStatus c 503 20 TxResponse c Service Unavailable 20 TxHeader c Server: Varnish 20 TxHeader c Content-Type: text/html; charset=utf-8 20 TxHeader c Retry-After: 5 20 TxHeader c Content-Length: 879 20 TxHeader c Accept-Ranges: bytes 20 TxHeader c Date: Wed, 06 Jun 2012 12:35:12 GMT 20 TxHeader c X-Varnish: 607335635 20 TxHeader c Age: 60 20 TxHeader c Via: 1.1 varnish 20 TxHeader c Connection: close 20 Length c 879 20 ReqEnd c 607335635 1338986052.649786949 1338986112.648169994 0.000160217 59.997980356 0.000402689 Now the backend server (apache) does not have any 503 error in the access log at this point. So I am confused. Is this varnish throwing a 503 because it thinks apache is to slow? There is a lot traffic coming through at this point so I know the server is up and running. I do have other 503 error codes with posts and gets so there is really no pattern. It seems to be at random times and random requests. Even in the morning when the server dosen't seem to be doing anything. I do see another pattern in the log: 4 VCL_call c recv pass 4 VCL_call c hash 4 Hash c /?id=412 4 VCL_return c hash 4 VCL_call c pass pass 4 FetchError c no backend connection 4 VCL_call c error deliver 4 VCL_call c deliver deliver Here fetcherror says "no backend connection". A summery of the FetchErrors in todays log: 16 FetchError c http first read error: -1 11 (No error recorded) 5 FetchError c http first read error: -1 11 (No error recorded) 4 FetchError c http first read error: -1 11 (No error recorded) 19 FetchError c http first read error: -1 11 (No error recorded) 5 FetchError c http first read error: -1 11 (No error recorded) 23 FetchError c http first read error: -1 11 (No error recorded) 24 FetchError c http first read error: -1 11 (No error recorded) 16 FetchError c http first read error: -1 11 (No error recorded) 6 FetchError c http first read error: -1 11 (No error recorded) 4 FetchError c http first read error: -1 11 (No error recorded) 5 FetchError c http first read error: -1 11 (No error recorded) 4 FetchError c http first read error: -1 11 (No error recorded) 4 FetchError c http first read error: -1 11 (No error recorded) 22 FetchError c http first read error: -1 11 (No error recorded) 6 FetchError c http first read error: -1 11 (No error recorded) 21 FetchError c http first read error: -1 11 (No error recorded) 26 FetchError c no backend connection 4 FetchError c no backend connection 20 FetchError c http first read error: -1 11 (No error recorded) 39 FetchError c http first read error: -1 11 (No error recorded) I haven't changed the default timeout values for varnish. This is my configuration for one of the backend servers. backend xenon { .host = "192.168.3.187"; .port = "80"; .probe = { .url = "/health-check/"; .interval = 3s; .window = 5; .threshold = 2; } } I'm running prefork module on apache2 with this configuration <IfModule mpm_prefork_module> StartServers 1 MinSpareServers 2 MaxSpareServers 5 MaxClients 200 MaxRequestsPerChild 75 </IfModule> and only PHP files is sent to the server. Every other static file is handled by Nginx. Any ideas? ------- EDIT -------------- Some more debuging information I have run a varnishadm debug.health Backend radon is Healthy Current states good: 5 threshold: 2 window: 5 Average responsetime of good probes: 0.002560 Oldest Newest ================================================================ 4444444444444444444444444444444444444444444444444444444444444444 Good IPv4 XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX Good Xmit RRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRR Good Recv HHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHH Happy Backend xenon is Healthy Current states good: 5 threshold: 2 window: 5 Average responsetime of good probes: 0.002760 Oldest Newest ================================================================ 4444444444444444444444444444444444444444444444444444444444444444 Good IPv4 XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX Good Xmit RRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRR Good Recv HHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHH Happy Backend iridium is Healthy Current states good: 5 threshold: 2 window: 5 Average responsetime of good probes: 0.000849 Oldest Newest ================================================================ 4444444444444444444444444444444444444444444444444444444444444444 Good IPv4 XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX Good Xmit RRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRR Good Recv HHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHH Happy Backend aurum is Healthy Current states good: 5 threshold: 2 window: 5 Average responsetime of good probes: 0.002100 Oldest Newest ================================================================ 4444444444444444444444444444444444444444444444444444444444444444 Good IPv4 XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX Good Xmit RRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRR Good Recv HHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHH Happy And I have been monitoring varnishstat from the two load balancers 3224774 3.99 2.61 backend_conn - Backend conn. success 27 0.00 0.00 backend_unhealthy - Backend conn. not attempted 63 0.00 0.00 backend_fail - Backend conn. failures 358798 0.00 0.29 backend_reuse - Backend conn. reuses 21035 0.00 0.02 backend_toolate - Backend conn. was closed 379834 0.00 0.31 backend_recycle - Backend conn. recycles 26 0.00 0.00 backend_retry - Backend conn. retry 3217751 5.99 2.61 backend_conn - Backend conn. success 32 0.00 0.00 backend_fail - Backend conn. failures 364185 0.00 0.30 backend_reuse - Backend conn. reuses 27077 0.00 0.02 backend_toolate - Backend conn. was closed 391263 0.00 0.32 backend_recycle - Backend conn. recycles 36 0.00 0.00 backend_retry - Backend conn. retry Notice that none of them have reported backend_fail. /Ronnie

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  • Algorithm for a lucky game [on hold]

    - by Ronnie
    Assume we have the following Keno(lottery type) game: From 80 numbers(from 1 to 80), 20 are being drawn. The players choose 1 or 2 or 3..... or 12 numbers to play(12 categories). If they choose for example 4 then they win if they predict correctly a certain amount of numbers(2,3 or 4) from the 4 they have played and lose if the predict only 1 or 0 numbers. They win X times their money accordingly to some predefined factor depending on how many numbers they predict from each category. The same with the other categories. And e.g 11 out of 11 gives 250000 times your money and 12 out of 12 gives 1000000 your money. So the company would want to avoid winnings so high. Every draw by the company is being made every 5 minutes and in each draw around 120000 (let's say) different predictions(Keno tickets) are being played. Let's assume 12000 are being played in category 10 and 12000 in category 11 and also 12000 in category 12. I'm wondering if there is an algorithm to allow the company that provides the game in the 5 minutes between the drawings, to find a 20 number set, in order to avoid any "12 out of 12" and "11 out of 11" and "11 out of 12" and "10 out of 11" and "10 out of 10" winning ticket. That means is there any algorithm, where in a time of less than 1 minute approximately(in todays hardware), to be able to find a 20 number set so that none of the 12000 12 and 11 and 10 number sets that the players played(in categories 10,11 and 12) contains any winning of "12 out of 12" and "11 out of 11" and "11 out of 12" and "10 out of 11" and "10 out of 10"? Or even better the generalization of the problem: What is the best algorithm(from a perspective of minimal time), to be able to find a Y number set from numbers 1 to Z(e.g Y=20, Z=80) so that none of the X sets of K-numbers that are being played(in category K) contains more than K-m numbers from the Y-set? (Note that for Y=K and m=1 there is a practical algorithm.)

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  • Linux installation on Acer Aspire One D270

    - by ronnie
    I was planning to buy Acer Aspire One D270 within a few days and as everybody installs linux on their netbook I was also planning to do that. Now, my question is how is Acer's hardware compatibility with linux and specifically in respect to the new Acer Aspire One D270. Has anybody tried installing linux on these new netbooks. It will be a great help if a D270 user can share his/her experience with linux usage. I read on some forums that there is some linux driver issue with Intel GMA 3600 and that people are not able to adjust their brightness. So, as I am a linux noob is this a major issue or not. Specs: RAM : 2Gb DDR3 Processor: Intel N2600(Cedar Trail) Graphics: Intel GMA 3600 HardDisk: 320Gb 5400 rpm

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