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  • Craftsmanship is ALL that Matters

    - by Wayne Molina
    Today, I'm going to talk about a touchy subject: the notion of working in a company that doesn't use the prescribed "best practices" in its software development endeavours.  Over the years I have, using a variety of pseudonyms, asked this question on popular programming forums.  Although I always add in some minor variation of the story to avoid suspicion that it's the same person posting, the crux of the tale remains the same: A Programmer’s Tale A junior software developer has just started a new job at an average company, creating average line-of-business applications for internal use (the most typical scenario programmers find themselves in).  This hypothetical newbie has spent a lot of time reading up on the "theory" of software development, devouring books, blogs and screencasts from well-known and respected software developers in the community in order to broaden his knowledge and "do what the pros do".  He begins his new job, eager to apply what he's learned on a real-world project only to discover that his new teammates doesn't use any of those concepts and techniques.  They hack their way through development, or in a best-case scenario use some homebrew, thrown-together semblance of a framework for their applications that follows not one of the best practices suggested by the “elite” in the software community - things like TDD (TDD as a "best practice" is the only subjective part of this post, but it's included here due to a very large following of respected developers who consider it one), the SOLID principles, well-known and venerable tools, even version control in a worst case and truly nightmarish scenario.  Our protagonist is frustrated that he isn't doing things the "proper" way - a way he's spent personal time digesting and learning about and, more importantly, a way that some of the top developers in the industry advocate - and turns to a forum to ask the advice of his peers. Invariably the answer I, in the guise of the concerned newbie, will receive is that A) I don't know anything and should just shut my mouth and sling code the bad way like everybody else on the team, and B) These "best practices" are fade or a joke, and the only thing that matters is shipping software to your customers. I am here today to say that anyone who says this, or anything like it, is not only full of crap but indicative of exactly the type of “developer” that has helped to give our industry a bad name.  Here is why: One Who Knows Nothing, Understands Nothing On one hand, you have the cognoscenti of the .NET development world.  Guys like James Avery, Jeremy Miller, Ayende Rahien and Rob Conery; all well-respected and noted programmers that are pretty much our version of celebrities.  These guys write blogs, books, and post videos outlining the "correct" way of writing software to make sure it not only works but is maintainable and extensible and a joy to work with.  They tout the virtues of the SOLID principles, or of using TDD/BDD, or using a mature ORM like NHibernate, Subsonic or even Entity Framework. On the other hand, you have Joe Everyman, Lead Software Developer at Initrode Corporation - in our hypothetical story Joe is the junior developer's new boss.  Joe's been with Initrode for 10 years, starting as the company’s very first programmer and over the years building up a little fiefdom of his own until at the present he’s in charge of all Initrode’s software development.  Joe writes code the same way he always has, without bothering to learn much, if anything.  He looked at NHibernate once and found it was "too hard", so he uses a primitive implementation of the TableDataGateway pattern as a wrapper around SqlClient.SqlConnection and SqlClient.SqlCommand instead of an actual ORM (or, in a better case scenario, has created his own ORM); the thought of using LINQ or Entity Framework or really anything other than his own hastily homebrew solution has never occurred to him.  He doesn't understand TDD and considers “testing” to be using the .NET debugger to step through code, or simply loading up an app and entering some values to see if it works.  He doesn't really understand SOLID, and he doesn't care to.  He's worked as a programmer for years, and that's all that counts.  Right?  WRONG. Who would you rather trust?  Someone with years of experience and who writes books, creates well-known software and is akin to a celebrity, or someone with no credibility outside their own minute environment who throws around their clout and company seniority as the "proof" of their ability?  Joe Everyman may have years of experience at Initrode as a programmer, and says to do things "his way" but someone like Jeremy Miller or Ayende Rahien have years of experience at companies just like Initrode, THEY know ten times more than Joe Everyman knows or could ever hope to know, and THEY say to do things "this way". Here's another way of thinking about it: If you wanted to get into politics and needed advice on the best way to do it, would you rather listen to the mayor of Hicktown, USA or Barack Obama?  One is a small-time nobody while the other is very well-known and, as such, would probably have much more accurate and beneficial advice. NOTE: The selection of Barack Obama as an example in no way, shape, or form suggests a political affiliation or political bent to this post or blog, and no political innuendo should be mistakenly read from it; the intent was merely to compare a small-time persona with a well-known persona in a non-software field.  Feel free to replace the name "Barack Obama" with any well-known Congressman, Senator or US President of your choice. DIY Considered Harmful I will say right now that the homebrew development environment is the WORST one for an aspiring programmer, because it relies on nothing outside it's own little box - no useful skill outside of the small pond.  If you are forced to use some half-baked, homebrew ORM created by your Director of Software, you are not learning anything valuable you can take with you in the future; now, if you plan to stay at Initrode for 10 years like Joe Everyman, this is fine and dandy.  However if, like most of us, you want to advance your career outside a very narrow space you will do more harm than good by sticking it out in an environment where you, to be frank, know better than everybody else because you are aware of alternative and, in almost most cases, better tools for the job.  A junior developer who understands why the SOLID principles are good to follow, or why TDD is beneficial, or who knows that it's better to use NHibernate/Subsonic/EF/LINQ/well-known ORM versus some in-house one knows better than a senior developer with 20 years experience who doesn't understand any of that, plain and simple.  Anyone who disagrees is either a liar, or someone who, just like Joe Everyman, Lead Developer, relies on seniority and tenure rather than adapting their knowledge as things evolve. In many cases, the Joe Everymans of the world act this way out of fear - they cannot possibly fathom that a “junior” could know more than them; after all, they’ve spent 10 or more years in the same company, doing the same job, cranking out the same shoddy software.  And here comes a newbie who hasn’t spent 10+ years doing the same things, with a fresh and often radical take on the craft, and Joe Everyman is afraid he might have to put some real effort into his career again instead of just pointing to his 10 years of service at Initrode as “proof” that he’s good, or that he might have to learn something new to improve; in most cases the problem is Joe Everyman, and by extension Initrode itself, has a mentality of just being “good enough”, and mediocrity is the rule of the day. A Thorn Bush is No Place for a Phoenix My advice is that if you work on a team where they don't use the best practices that some of the most famous developers in our field say is the "right" way to do things (and have legions of people who agree), and YOU are aware of these practices and can see why they work, then LEAVE the company.  Find a company where they DO care about quality, and craftsmanship, otherwise you will never be happy.  There is no point in "dumbing" yourself down to the level of your co-workers and slinging code without care to craftsmanship.  In 95% of these situations there will be no point in bringing it to the attention of Joe Everyman because he won't listen; he might even get upset that someone is trying to "upstage" him and fire the newbie, and replace someone with loads of untapped potential with a drone that will just nod affirmatively and grind out the tasks assigned without question. Find a company that has people smart enough to listen to the "best and brightest", and be happy.  Do not, I repeat, DO NOT waste away in a job working for ignorant people.  At the end of the day software development IS a craft, and a level of craftsmanship is REQUIRED for any serious professional.  When you have knowledgeable people with the credibility to back it up saying one thing, and small-time people who are, to put it bluntly, nobodies in the field saying and doing something totally different because they can't comprehend it, leave the nobodies to their own devices to fade into obscurity.  Work for a company that uses REAL software engineering techniques and really cares about craftsmanship.  The biggest issue affecting our career, and the reason software development has never been the respected, white-collar career it was meant to be, is because hacks and charlatans can pass themselves off as professional programmers without following a lick of good advice from programmers much better at the craft than they are.  These modern day snake-oil salesmen entrench themselves in companies by hoodwinking non-technical businesspeople and customers with their shoddy wares, end up in senior/lead/executive positions, and push their lack of knowledge on everybody unfortunate enough to work with/for/under them, crushing any dissent or voices of reason and change under their tyrannical heel and leaving behind a trail of dismayed and, often, unemployed junior developers who were made examples of to keep up the facade and avoid the shadow of doubt being cast upon them. To sum this up another way: If you surround yourself with learned people, you will learn.  Surround yourself with ignorant people who can't, as the saying goes, see the forest through the trees, and you'll learn nothing of any real value.  There is more to software development than just writing code, and the end goal should not be just "shipping software", it should be shipping software that is extensible, maintainable, and above all else software whose creation has broadened your knowledge in some capacity, even if a minor one.  An eager newbie who knows theory and thirsts for knowledge can easily be moulded and taught the advanced topics, but the same can't be said of someone who only cares about the finish line.  This industry needs more people espousing the benefits of software craftsmanship and proper software engineering techniques, and less Joe Everymans who are unwilling to adapt or foster new ways of thinking. Conclusion - I Cast “Protection from Fire” I am fairly certain this post will spark some controversy and might even invite the flames.  Please keep in mind these are opinions and nothing more.  A little healthy rant and subsequent flamewar can be good for the soul once in a while.  To paraphrase The Godfather: It helps to get rid of the bad blood.

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  • /dev/sda1 not a subset of /dev/sda?

    - by Guillaume Brunerie
    Hi, the first entry of my partition table is: $ sudo hexdump -Cv -n 16 -s 446 /dev/sda 000001be 80 01 01 00 83 fe ff ff 3f 00 00 00 81 1c 20 03 |........?..... .| (-Cv describe the output format, -n 16 asks for 16 bytes and -s 446 skips the first 446 bytes) You can see that my first partition is a primary Linux partition and that this partition begin at sector 63 (see for example here for the structure of the partition table). I would then expect that except for the first 63 sectors and the other partitions, /dev/sda1 and /dev/sda are exactly the same. But this is not the case, the sector #2 of /dev/sda1 is not exactly the same as the sector #65 of /dev/sda (but they are very similar, only 16 bytes are different): $ sudo hexdump -Cv -n 512 -s 65b /dev/sda 00008200 00 20 19 00 90 03 64 00 2d 00 05 00 5a 2f 56 00 |. ....d.-...Z/V.| 00008210 b6 b1 16 00 00 00 00 00 02 00 00 00 02 00 00 00 |................| 00008220 00 80 00 00 00 80 00 00 00 20 00 00 d8 38 ee 4c |......... ...8.L| 00008230 9a 01 ef 4c 05 00 24 00 53 ef 01 00 01 00 00 00 |...L..$.S.......| 00008240 59 23 e9 4c 00 4e ed 00 00 00 00 00 01 00 00 00 |Y#.L.N..........| 00008250 00 00 00 00 0b 00 00 00 00 01 00 00 3c 00 00 00 |............<...| 00008260 42 02 00 00 7b 00 00 00 85 23 eb f2 71 67 44 f5 |B...{....#..qgD.| 00008270 bb 8f 6f f2 3a 59 ff 4d 55 62 75 6e 74 75 00 00 |..o.:Y.MUbuntu..| 00008280 00 00 00 00 00 00 00 00 2f 75 62 75 6e 74 75 00 |......../ubuntu.| 00008290 d8 3c df 5d 00 88 ff ff 52 d0 ef 1d 00 00 00 00 |.<.]....R.......| 000082a0 c0 40 51 b6 00 88 ff ff 00 4e c8 bb 00 88 ff ff |[email protected]......| 000082b0 c0 f6 86 b8 00 88 ff ff 30 2e 0d a0 ff ff ff ff |........0.......| 000082c0 38 3d df 5d 00 88 ff ff 00 00 00 00 00 00 fe 03 |8=.]............| 000082d0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................| 000082e0 08 00 00 00 00 00 00 00 00 00 00 00 8a 53 d3 0e |.............S..| 000082f0 7c 7a 43 e4 8b fb ca e0 72 b7 fa c8 01 01 00 00 ||zC.....r.......| 00008300 00 00 00 00 00 00 00 00 16 4c 47 4b 0a f3 03 00 |.........LGK....| 00008310 04 00 00 00 00 00 00 00 00 00 00 00 fe 7f 00 00 |................| 00008320 24 b7 0c 00 fe 7f 00 00 01 00 00 00 22 37 0d 00 |$..........."7..| 00008330 ff 7f 00 00 01 00 00 00 23 37 0d 00 00 00 00 00 |........#7......| 00008340 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 08 |................| 00008350 00 00 00 00 00 00 00 00 00 00 00 00 1c 00 1c 00 |................| 00008360 01 00 00 00 e9 7f 00 00 00 00 00 00 00 00 00 00 |................| 00008370 00 00 00 00 04 00 00 00 9f 7d bb 00 00 00 00 00 |.........}......| 00008380 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................| 00008390 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................| 000083a0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................| 000083b0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................| 000083c0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................| 000083d0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................| 000083e0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................| 000083f0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................| versus $ sudo hexdump -Cv -n 512 -s 2b /dev/sda1 00000400 00 20 19 00 90 03 64 00 2d 00 05 00 5a 2f 56 00 |. ....d.-...Z/V.| 00000410 b6 b1 16 00 00 00 00 00 02 00 00 00 02 00 00 00 |................| 00000420 00 80 00 00 00 80 00 00 00 20 00 00 df 76 ef 4c |......... ...v.L| 00000430 df 76 ef 4c 06 00 24 00 53 ef 01 00 01 00 00 00 |.v.L..$.S.......| 00000440 59 23 e9 4c 00 4e ed 00 00 00 00 00 01 00 00 00 |Y#.L.N..........| 00000450 00 00 00 00 0b 00 00 00 00 01 00 00 3c 00 00 00 |............<...| 00000460 46 02 00 00 7b 00 00 00 85 23 eb f2 71 67 44 f5 |F...{....#..qgD.| 00000470 bb 8f 6f f2 3a 59 ff 4d 55 62 75 6e 74 75 00 00 |..o.:Y.MUbuntu..| 00000480 00 00 00 00 00 00 00 00 2f 75 62 75 6e 74 75 00 |......../ubuntu.| 00000490 d8 3c df 5d 00 88 ff ff 52 d0 ef 1d 00 00 00 00 |.<.]....R.......| 000004a0 c0 40 51 b6 00 88 ff ff 00 4e c8 bb 00 88 ff ff |[email protected]......| 000004b0 c0 f6 86 b8 00 88 ff ff 30 2e 0d a0 ff ff ff ff |........0.......| 000004c0 38 3d df 5d 00 88 ff ff 00 00 00 00 00 00 fe 03 |8=.]............| 000004d0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................| 000004e0 08 00 00 00 00 00 00 00 00 00 00 00 8a 53 d3 0e |.............S..| 000004f0 7c 7a 43 e4 8b fb ca e0 72 b7 fa c8 01 01 00 00 ||zC.....r.......| 00000500 00 00 00 00 00 00 00 00 16 4c 47 4b 0a f3 03 00 |.........LGK....| 00000510 04 00 00 00 00 00 00 00 00 00 00 00 fe 7f 00 00 |................| 00000520 24 b7 0c 00 fe 7f 00 00 01 00 00 00 22 37 0d 00 |$..........."7..| 00000530 ff 7f 00 00 01 00 00 00 23 37 0d 00 00 00 00 00 |........#7......| 00000540 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 08 |................| 00000550 00 00 00 00 00 00 00 00 00 00 00 00 1c 00 1c 00 |................| 00000560 01 00 00 00 e9 7f 00 00 00 00 00 00 00 00 00 00 |................| 00000570 00 00 00 00 04 00 00 00 a3 7d bb 00 00 00 00 00 |.........}......| 00000580 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................| 00000590 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................| 000005a0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................| 000005b0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................| 000005c0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................| 000005d0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................| 000005e0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................| 000005f0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................| For example in the third line, there is a 8.L in the first hexdump and v.L in the second. Why are there differences?

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  • Glassfish alive or dead? WebLogic SE cost is less than Glassfish!

    - by JuergenKress
    Is a hot discussion in the community in the last few days! Send us your opinion on tiwtter @wlscommunity #Glassfish #WebLogicCommunity We posted theGlassFishStrategy.pptx at our WebLogic Community Workspace (WebLogic Community membership required). Please read also the Java EE and GlassFish Server Roadmap Update Bruno Borges ?Another great article covering story about #GlassFish. Comments starting to be reasonable ;-) 6 facts helped a lot http://adtmag.com/articles/2013/11/08/oracle-drops-glassfish.aspx … Adam Bien ?What Oracle Could Do For GlassFish Now: Move the sources to GitHub (GitHub is the most popular collaboration p... http://bit.ly/1d1uo24 JAXenter.com ?Oracle evangelist: “GlassFish Open Source Edition is not dead” http://jaxenter.com/oracle-evangelist-glassfish-open-source-edition-is-not-dead-48830.html … GlassFish 6 Facts About #GlassFish Announcement and the Future of #JavaEE http://bit.ly/1bbSVPf via @brunoborges David Blevins ?In support of our #GlassFish friends and open source in general: Feed the Fish http://www.tomitribe.com/blog/2013/11/feed-the-fish/ … #JavaEE #opensource #manifesto GlassFish ?GlassFish Server Open Source Edition 4.1 is scheduled for 2014. Version 5.0 as impl for #JavaEE8 https://blogs.oracle.com/theaquarium/entry/java_ee_and_glassfish_server … #Community focused C2B2 Consulting ?C2B2 continues to offer support for your operational #JEE applications running on #GlassFish http://blog.c2b2.co.uk/2013/11/oracle-dropping-commercial-support-of.html … #Java Markus Eisele ?RT @InfoQ: #GlassFish Commercial Edition is Dead http://bit.ly/17eFB0Z < at least they agree to my points... Adam Bien suggests: Move the sources to GitHub (GitHub is the most popular collaboration platform). It is more likely for an individual to contribute via GitHub, than the current infrastructure. Introduce a business friendlier license like e.g. the Apache license. Companies interesting in providing added value (and commercial support) on top of existing sources would appreciate it. Implement GitHub-based, open source, CI system with nightly builds. Introduce a transparent voting process / pull-request acceptance process. Release more frequently. Keep https://glassfish.java.net as the main hub. C2B2 offers Glassfish support by Steve Millidge Oracle have just announced that commercial support for GlassFish 4 will not be available from Oracle. In light of this announcement I thought I would put together some thoughts about how I see this development. I think the key word in this announcement is "commercial", nowhere does Oracle announce the "death of GlassFish" in contrary Oracle reaffirm; GlassFish Server Open Source Edition continues to be the strategic foundation for Java EE reference implementation going forward. And for developers, updates will be delivered as needed to continue to deliver a great developer experience for GlassFish Server Open Source Edition so GlassFish is not about to go away soon. In a similar fashion RedHat do not provide commercial support for WildFly and only provide commercial support for JBoss EAP. Admittedly JBoss EAP and WildFly are much closer together than GlassFish and WebLogic but WildFly and JBoss EAP are absolutely NOT the same thing. The key going forward to the viability of GlassFish as a production platform is how the GlassFish community develops; How often does the community release binary builds? How open is the community to bug fixes? How much engineering resource does Oracle commit to GlassFish? At this stage we just don't know the answers to these questions. If the GlassFish open source project continues on it's current trajectory without a commercial support offering then I don't see much of a problem. Oracle just have to work harder to sell migration paths to WebLogic in the same way as RedHat have to sell migration paths from WildFly to JBoss EAP. In the meantime C2B2 continues to offer support for your operational JEE applications running on GlassFish and we will endeavour to work with the community to get any bugs fixed. The key difference is we can no longer back our Expert Support with a support contract from Oracle for patches and fixes for any release greater than 3.x. Read the complete article here. 6 Facts About GlassFish Announcement By Bruno.Borges Fact #1 - GlassFish Open Source Edition is not dead GlassFish Server Open Source Edition will remain the reference implementation of Java EE. The current trunk is where an implementation for Java EE 8 will flourish, and this will become the future GlassFish 5.0. Calling "GlassFish is dead" does no good to the Java EE ecosystem. The GlassFish Community will remain strong towards the future of Java EE. Without revenue-focused mind, this might actually help the GlassFish community to shape the next version, and set free from any ties with commercial decisions. Fact #2 - OGS support is not over As I said before, GlassFish Server Open Source Edition will continue. Main change is that there will be no more future commercial releases of Oracle GlassFish Server. New and existing OGS 2.1.x and 3.1.x commercial customers will continue to be supported according to the Oracle Lifetime Support Policy. In parallel, I believe there's no other company in the Java EE business that offers commercial support to more than one build of a Java EE application server. This new direction can actually help customers and partners, simplifying decision through commercial negotiations. Fact #3 - WebLogic is not always more expensive than OGS Oracle GlassFish Server ("OGS") is a build of GlassFish Server Open Source Edition bundled with a set of commercial features called GlassFish Server Control and license bundles such as Java SE Support. OGS has at the moment of this writing the pricelist of U$ 5,000 / processor. One information that some bloggers are mentioning is that WebLogic is more expensive than this. Fact 3.1: it is not necessarily the case. The initial edition of WebLogic is called "Standard Edition" and falls into a policy where some “Standard Edition” products are licensed on a per socket basis. As of current pricelist, US$ 10,000 / socket. If you do the math, you will realize that WebLogic SE can actually be significantly more cost effective than OGS, and a customer can save money if running on a CPU with 4 cores or more for example. Quote from the price list: “When licensing Oracle programs with Standard Edition One or Standard Edition in the product name (with the exception of Java SE Support, Java SE Advanced, and Java SE Suite), a processor is counted equivalent to an occupied socket; however, in the case of multi-chip modules, each chip in the multi-chip module is counted as one occupied socket.” For more details speak to your Oracle sales representative - this is clearly at list price and every customer typically has a relationship with Oracle (like they do with other vendors) and different contractual details may apply. And although OGS has always been production-ready for Java EE applications, it is no secret that WebLogic has always been more enterprise, mission critical application server than OGS since BEA. Different editions of WLS provide features and upgrade irons like the WebLogic Diagnostic Framework, Work Managers, Side by Side Deployment, ADF and TopLink bundled license, Web Tier (Oracle HTTP Server) bundled licensed, Fusion Middleware stack support, Oracle DB integration features, Oracle RAC features (such as GridLink), Coherence Management capabilities, Advanced HA (Whole Service Migration and Server Migration), Java Mission Control, Flight Recorder, Oracle JDK support, etc. Fact #4 - There’s no major vendor supporting community builds of Java EE app servers There are no major vendors providing support for community builds of any Open Source application server. For example, IBM used to provide community support for builds of Apache Geronimo, not anymore. Red Hat does not commercially support builds of WildFly and if I remember correctly, never supported community builds of former JBoss AS. Oracle has never commercially supported GlassFish Server Open Source Edition builds. Tomitribe appears to be the exception to the rule, offering commercial support for Apache TomEE. Fact #5 - WebLogic and GlassFish share several Java EE implementations It has been no secret that although GlassFish and WebLogic share some JSR implementations (as stated in the The Aquarium announcement: JPA, JSF, WebSockets, CDI, Bean Validation, JAX-WS, JAXB, and WS-AT) and WebLogic understands GlassFish deployment descriptors, they are not from the same codebase. Fact #6 - WebLogic is not for GlassFish what JBoss EAP is for WildFly WebLogic is closed-source offering. It is commercialized through a license-based plus support fee model. OGS although from an Open Source code, has had the same commercial model as WebLogic. Still, one cannot compare GlassFish/WebLogic to WildFly/JBoss EAP. It is simply not the same case, since Oracle has had two different products from different codebases. The comparison should be limited to GlassFish Open Source / Oracle GlassFish Server versus WildFly / JBoss EAP. Read the complete article here WebLogic Partner Community For regular information become a member in the WebLogic Partner Community please visit: http://www.oracle.com/partners/goto/wls-emea ( OPN account required). If you need support with your account please contact the Oracle Partner Business Center. Blog Twitter LinkedIn Mix Forum Wiki Technorati Tags: Glassfish,training,WebLogic,WebLogic Community,Oracle,OPN,Jürgen Kress

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  • C#: Why Decorate When You Can Intercept

    - by James Michael Hare
    We've all heard of the old Decorator Design Pattern (here) or used it at one time or another either directly or indirectly.  A decorator is a class that wraps a given abstract class or interface and presents the same (or a superset) public interface but "decorated" with additional functionality.   As a really simplistic example, consider the System.IO.BufferedStream, it itself is a descendent of System.IO.Stream and wraps the given stream with buffering logic while still presenting System.IO.Stream's public interface:   1: Stream buffStream = new BufferedStream(rawStream); Now, let's take a look at a custom-code example.  Let's say that we have a class in our data access layer that retrieves a list of products from a database:  1: // a class that handles our CRUD operations for products 2: public class ProductDao 3: { 4: ... 5:  6: // a method that would retrieve all available products 7: public IEnumerable<Product> GetAvailableProducts() 8: { 9: var results = new List<Product>(); 10:  11: // must create the connection 12: using (var con = _factory.CreateConnection()) 13: { 14: con.ConnectionString = _productsConnectionString; 15: con.Open(); 16:  17: // create the command 18: using (var cmd = _factory.CreateCommand()) 19: { 20: cmd.Connection = con; 21: cmd.CommandText = _getAllProductsStoredProc; 22: cmd.CommandType = CommandType.StoredProcedure; 23:  24: // get a reader and pass back all results 25: using (var reader = cmd.ExecuteReader()) 26: { 27: while(reader.Read()) 28: { 29: results.Add(new Product 30: { 31: Name = reader["product_name"].ToString(), 32: ... 33: }); 34: } 35: } 36: } 37: }            38:  39: return results; 40: } 41: } Yes, you could use EF or any myriad other choices for this sort of thing, but the germaine point is that you have some operation that takes a non-trivial amount of time.  What if, during the production day I notice that my application is performing slowly and I want to see how much of that slowness is in the query versus my code.  Well, I could easily wrap the logic block in a System.Diagnostics.Stopwatch and log the results to log4net or other logging flavor of choice: 1:     // a class that handles our CRUD operations for products 2:     public class ProductDao 3:     { 4:         private static readonly ILog _log = LogManager.GetLogger(typeof(ProductDao)); 5:         ... 6:         7:         // a method that would retrieve all available products 8:         public IEnumerable<Product> GetAvailableProducts() 9:         { 10:             var results = new List<Product>(); 11:             var timer = Stopwatch.StartNew(); 12:             13:             // must create the connection 14:             using (var con = _factory.CreateConnection()) 15:             { 16:                 con.ConnectionString = _productsConnectionString; 17:                 18:                 // and all that other DB code... 19:                 ... 20:             } 21:             22:             timer.Stop(); 23:             24:             if (timer.ElapsedMilliseconds > 5000) 25:             { 26:                 _log.WarnFormat("Long query in GetAvailableProducts() took {0} ms", 27:                     timer.ElapsedMillseconds); 28:             } 29:             30:             return results; 31:         } 32:     } In my eye, this is very ugly.  It violates Single Responsibility Principle (SRP), which says that a class should only ever have one responsibility, where responsibility is often defined as a reason to change.  This class (and in particular this method) has two reasons to change: If the method of retrieving products changes. If the method of logging changes. Well, we could “simplify” this using the Decorator Design Pattern (here).  If we followed the pattern to the letter, we'd need to create a base decorator that implements the DAOs public interface and forwards to the wrapped instance.  So let's assume we break out the ProductDAO interface into IProductDAO using your refactoring tool of choice (Resharper is great for this). Now, ProductDao will implement IProductDao and get rid of all logging logic: 1:     public class ProductDao : IProductDao 2:     { 3:         // this reverts back to original version except for the interface added 4:     } 5:  And we create the base Decorator that also implements the interface and forwards all calls: 1:     public class ProductDaoDecorator : IProductDao 2:     { 3:         private readonly IProductDao _wrappedDao; 4:         5:         // constructor takes the dao to wrap 6:         public ProductDaoDecorator(IProductDao wrappedDao) 7:         { 8:             _wrappedDao = wrappedDao; 9:         } 10:         11:         ... 12:         13:         // and then all methods just forward their calls 14:         public IEnumerable<Product> GetAvailableProducts() 15:         { 16:             return _wrappedDao.GetAvailableProducts(); 17:         } 18:     } This defines our base decorator, then we can create decorators that add items of interest, and for any methods we don't decorate, we'll get the default behavior which just forwards the call to the wrapper in the base decorator: 1:     public class TimedThresholdProductDaoDecorator : ProductDaoDecorator 2:     { 3:         private static readonly ILog _log = LogManager.GetLogger(typeof(TimedThresholdProductDaoDecorator)); 4:         5:         public TimedThresholdProductDaoDecorator(IProductDao wrappedDao) : 6:             base(wrappedDao) 7:         { 8:         } 9:         10:         ... 11:         12:         public IEnumerable<Product> GetAvailableProducts() 13:         { 14:             var timer = Stopwatch.StartNew(); 15:             16:             var results = _wrapped.GetAvailableProducts(); 17:             18:             timer.Stop(); 19:             20:             if (timer.ElapsedMilliseconds > 5000) 21:             { 22:                 _log.WarnFormat("Long query in GetAvailableProducts() took {0} ms", 23:                     timer.ElapsedMillseconds); 24:             } 25:             26:             return results; 27:         } 28:     } Well, it's a bit better.  Now the logging is in its own class, and the database logic is in its own class.  But we've essentially multiplied the number of classes.  We now have 3 classes and one interface!  Now if you want to do that same logging decorating on all your DAOs, imagine the code bloat!  Sure, you can simplify and avoid creating the base decorator, or chuck it all and just inherit directly.  But regardless all of these have the problem of tying the logging logic into the code itself. Enter the Interceptors.  Things like this to me are a perfect example of when it's good to write an Interceptor using your class library of choice.  Sure, you could design your own perfectly generic decorator with delegates and all that, but personally I'm a big fan of Castle's Dynamic Proxy (here) which is actually used by many projects including Moq. What DynamicProxy allows you to do is intercept calls into any object by wrapping it with a proxy on the fly that intercepts the method and allows you to add functionality.  Essentially, the code would now look like this using DynamicProxy: 1: // Note: I like hiding DynamicProxy behind the scenes so users 2: // don't have to explicitly add reference to Castle's libraries. 3: public static class TimeThresholdInterceptor 4: { 5: // Our logging handle 6: private static readonly ILog _log = LogManager.GetLogger(typeof(TimeThresholdInterceptor)); 7:  8: // Handle to Castle's proxy generator 9: private static readonly ProxyGenerator _generator = new ProxyGenerator(); 10:  11: // generic form for those who prefer it 12: public static object Create<TInterface>(object target, TimeSpan threshold) 13: { 14: return Create(typeof(TInterface), target, threshold); 15: } 16:  17: // Form that uses type instead 18: public static object Create(Type interfaceType, object target, TimeSpan threshold) 19: { 20: return _generator.CreateInterfaceProxyWithTarget(interfaceType, target, 21: new TimedThreshold(threshold, level)); 22: } 23:  24: // The interceptor that is created to intercept the interface calls. 25: // Hidden as a private inner class so not exposing Castle libraries. 26: private class TimedThreshold : IInterceptor 27: { 28: // The threshold as a positive timespan that triggers a log message. 29: private readonly TimeSpan _threshold; 30:  31: // interceptor constructor 32: public TimedThreshold(TimeSpan threshold) 33: { 34: _threshold = threshold; 35: } 36:  37: // Intercept functor for each method invokation 38: public void Intercept(IInvocation invocation) 39: { 40: // time the method invocation 41: var timer = Stopwatch.StartNew(); 42:  43: // the Castle magic that tells the method to go ahead 44: invocation.Proceed(); 45:  46: timer.Stop(); 47:  48: // check if threshold is exceeded 49: if (timer.Elapsed > _threshold) 50: { 51: _log.WarnFormat("Long execution in {0} took {1} ms", 52: invocation.Method.Name, 53: timer.ElapsedMillseconds); 54: } 55: } 56: } 57: } Yes, it's a bit longer, but notice that: This class ONLY deals with logging long method calls, no DAO interface leftovers. This class can be used to time ANY class that has an interface or virtual methods. Personally, I like to wrap and hide the usage of DynamicProxy and IInterceptor so that anyone who uses this class doesn't need to know to add a Castle library reference.  As far as they are concerned, they're using my interceptor.  If I change to a new library if a better one comes along, they're insulated. Now, all we have to do to use this is to tell it to wrap our ProductDao and it does the rest: 1: // wraps a new ProductDao with a timing interceptor with a threshold of 5 seconds 2: IProductDao dao = TimeThresholdInterceptor.Create<IProductDao>(new ProductDao(), 5000); Automatic decoration of all methods!  You can even refine the proxy so that it only intercepts certain methods. This is ideal for so many things.  These are just some of the interceptors we've dreamed up and use: Log parameters and returns of methods to XML for auditing. Block invocations to methods and return default value (stubbing). Throw exception if certain methods are called (good for blocking access to deprecated methods). Log entrance and exit of a method and the duration. Log a message if a method takes more than a given time threshold to execute. Whether you use DynamicProxy or some other technology, I hope you see the benefits this adds.  Does it completely eliminate all need for the Decorator pattern?  No, there may still be cases where you want to decorate a particular class with functionality that doesn't apply to the world at large. But for all those cases where you are using Decorator to add functionality that's truly generic.  I strongly suggest you give this a try!

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  • If Nvidia Shield can stream a game via WiFi (~150-300Mbps), where is the 1-10Gbps wired streaming?

    - by Enigma
    Facts: It is surprising and uncharacteristic that a wireless game streaming solution is the *first to hit the market when a 1000mbps+ Ethernet connection would accomplish the same feat with roughly 6x the available bandwidth. 150-300mbps WiFi is in no way superior to a 1000mbps+ LAN connection aside from well wireless mobility. Throughout time, (since the internet was created) wired services have **always come first yet in this particular case, the opposite seems to be true. We had wired internet first, wired audio streaming, and wired video streaming all before their wireless counterparts. Why? Largely because the wireless bandwidth was and is inferior. Even today despite being significantly better and capable of a lot more, it is still inferior to a wired connection. Situation: Chief among these is that NVIDIA’s Shield handheld game console will be getting a microconsole-like mode, dubbed “Shield Console Mode”, that will allow the handheld to be converted into a more traditional TV-connected console. In console mode Shield can be controlled with a Bluetooth controller, and in accordance with the higher resolution of TVs will accept 1080p game streaming from a suitably equipped PC, versus 720p in handheld mode. With that said 1080p streaming will require additional bandwidth, and while 720p can be done over WiFi NVIDIA will be requiring a hardline GigE connection for 1080p streaming (note that Shield doesn’t have Ethernet, so this is presumably being done over USB). Streaming aside, in console mode Shield will also support its traditional local gaming/application functionality. - http://www.anandtech.com/show/7435/nvidia-consolidates-game-streaming-tech-under-gamestream-brand-announces-shield-console-mode ^ This is not acceptable to me for a number of reasons not to mention the ridiculousness of having a little screen+controller unit sitting there while using a secondary controller and screen instead. That kind of redundant absurdity exemplifies how wrong of a solution that is. They need a second product for this solution without the screen or controller for it to make sense... at which point your just buying a little computer that does what most other larger computers do better. While this secondary project will provide a wired connection, it still shouldn't be necessary to purchase a Shield to have this benefit. Not only this but Intel's WiDi claims game streaming support as well - wirelessly. Where is the wired streaming? All that is required, by my understanding, is the ability to decode H.264 video compression and transmit control/feedback so by any logical comparison, one (Nvidia especially) should have no difficulty in creating an application for PC's (win32/64 environment) that does the exact same thing their android app does. I have 2 video cards capable of streaming (encoding) H.264 so by right they must be capable of decoding it I would think. I should be able to stream to my second desktop or my laptop both of which by hardware comparison are superior to the Shield. I haven't found anything stating plans to allow non-shield owners to do this. Can a third party create this software or does it hinge on some limitation that only Nvidia can overcome? Reiteration of questions: Is there a technical reason (non marketing) for why Nvidia opted to bottleneck the streaming service with a wireless connection limiting the resolution to 720p and introducing intermittent video choppiness when on a wired connection one could achieve, presumably, 1080p with significantly less or zero choppiness? Is there anything limiting developers from creating a PC/Desktop application emulating the same H.264 decoding functionality that circumvents the need to get an Nvidia Shield altogether? (It is not a matter of being too cheap to support Nvidia - I have many Nvidia cards that aren't being used. One should not have to purchase specialty hardware when = hardware already exists) Same questions go for Intel Widi also. I am just utterly perplexed that there are wireless live streaming solution and yet no wired. How on earth can wireless be the goto transmission medium? Is there another solution that takes advantage of H.264 video compression allowing live streaming over a wired connection? (*) - Perhaps this isn't the first but afaik it is the first complete package. (**) - I cant back that up with hard evidence/links but someone probably could. Edit: Maybe this will be the solution I am looking for but I still find it hard to believe that they would be the first and after wireless solutions already exist. In-home Streaming You can play all your Windows and Mac games on your SteamOS machine, too. Just turn on your existing computer and run Steam as you always have - then your SteamOS machine can stream those games over your home network straight to your TV! - http://store.steampowered.com/livingroom/SteamOS/

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  • Clean Code Developer & Certification in IT - MSCC 21.09.2013

    It was a very busy weekend this time, and quite some hectic to organise the second meetup on a Saturday for the Mauritius Software Craftsmanship Community (MSCC) but it was absolutely fun. Following, I'm writing a brief summary about the topics we spoke about and the new impulses I got. "What a meetup... I was positively impressed. At the beginning I thought that noone would actually show up but then by the time the room got filled. Lots of conversation, great dialogues and fantastic networking between fresh students, experienced students, experienced employees, and self-employed attendees. That's what community is all about!" Above quote was my first reaction shortly after the gathering. And despite being busy during the weekend and yesterday, I took my time to reflect a little bit on things happened and statements made before writing it here on my blog. Additionally, I was also very curious about possible reactions and blogs from other attendees. Reactions from other craftsmen Let me quickly give you some links and quotes from others first... "Like Jochen posted on facebook, that was indeed a 5+ hours marathon (maybe 4 hours for me but still) … Wohoo! We’re indeed a bunch of crazy geeks who did not realise how time flew as we dived into the myriad discussions that sprouted. Yet in the end everyone was happy (:" -- Ish on MSCC meetup - The marathon (: "And the 4hours spent @ Talking drums bore its fruit..I was doing something I never did before....reading the borrowed book while walking....and though I was not that familiar with things mentionned in the book...I was skimming,scanning & flipping...reading titles...short paragraphs...and I skipped pages till I reached home." -- Yannick on Mauritius Software Craftsmanship 1st Meet-up "Hi Developers, Just wanted to share with you the meetups i attended last Saturday - [...] - The second meetup is the one hosted by Jochen Kirstätter, the MSCC, where the attendees were Craftsman, no woman, this time - all sharing the same passion of being a developer - even though it is on different platforms(Windows - Windows Phone - Linux - Adobe(yes a designer) - .Net) - but we manage to sit at the same table - sharing developer views and experience in the corporate world - also talking about good practice when coding( where Jochen initiated a discussion on Clean Coding ) i could not stay till the end - but from what i have heard - the longer you stay the more fun you have till 1600. Developers in the Facebook grouping i invite you to stay tuned about the various developer communities popping up - where you can come to share and learn good practices, develop the entrepreneurial spirit, and learn and share your passion about technologies" -- Arnaud on Facebook More feedback has been posted on the event directly. So, should I really write more? Wouldn't that spoil the impressions? Starting the day with a surprise Indeed, I was very pleased to stumble over the existence of Mobile Monday Mauritius on LinkedIn, an association about any kind of mobile app development, mobile gadgets and latest smartphones on the market. Despite the Monday in their name they had scheduled their recent meeting on Saturday between 10:00 and 12:00hrs. Wow, what a coincidence! Let's grap the bull by its horns and pay them an introductory visit. As they chose the Ebene Accelerator at the Orange Tower in Ebene it was a no-brainer to leave home a bit earlier and stop by. It was quite an experience and fun to talk to the geeks over there. Really looking forward to organise something together.... Arriving at the venue As the children got a bit uneasy at the MoMo gathering and I didn't want to disturb them too much, we arrived early at Bagatelle. Well, no problems as we went for a decent breakfast at Food Lover's Market. Shortly afterwards we went to our venue location, Talking Drums, and prepared the room for the meeting. We only had to take off a repro-painting of the wall in order to have a decent area for the projector. All went very smooth and my two little ones were of great help. Just in time, our first craftsman Avinash arrived on the spot. And then the waiting started... Luckily, not too long. Bit by bit more and more IT people came to join our meeting. Meanwhile, I used the time to give a brief introduction about the MSCC in general, what we are (hm, maybe I am) trying to achieve and that the recent phase is completely focused on creating more awareness that a community like the MSCC is active here in Mauritius. As soon as we reached some 'critical mass' of about ten people I asked everyone for a short introduction and bio, just in case... Conversation between participants started to kick in and we were actually more networking than having a focus on our topics of the day. Quick updates on latest news and development around the MSCC Finally, Clean Code Developer No matter how the position is actually called, whether it is Software Engineer, Software Developer, Programmer, Architect, or Craftsman, anyone working in IT is facing almost the same obstacles. As for the process of writing software applications there are re-occurring patterns and principles combined with some common exercise and best practices on how to resolve them. Initiated by the must-read book 'Clean Code' by Robert C. Martin (aka Uncle Bob) the concept of the Clean Code Developer (CCD) was born already some years ago. CCD is much likely to traditional martial arts where you create awareness of certain principles and learn how to apply practices to improve your style. The CCD initiative recommends to indicate your level of knowledge and experience with coloured wrist bands - equivalent to the belt colours - for various reasons. Frankly speaking, I think that the biggest advantage here is provided by the obvious recognition of conceptual understanding. For example, take the situation of a team meeting... A member with a higher grade in CCD, say Green grade, sees that there are mainly Red grades to talk to, and adjusts her way of communication to their level of understanding. The choice of words might change as certain elements of CCD are not yet familiar to all team members. So instead of talking in an abstract way which only Green grades could follow the whole scenario comes down to Red grade level. Different story, better results... Similar to learning martial arts, we only covered two grades during this occasion - black and red. Most interestingly, there was quite some positive feedback and lots of questions about the principles and practices of the red grade. And we gathered real-world examples from various craftsman and discussed them. Following the Clean Code Developer Red Grade and some annotations from our meetup: CCD Red Grade - Principles Don't Repeat Yourself - DRY Keep It Simple, Stupid (and Short) - KISS Beware of Optimisations! Favour Composition over Inheritance - FCoI Interestingly most of the attendees already heard about those key words but couldn't really classify or categorize them. It's very similar to a situation in which you do not the particular for a thing and have to describe it to others... until someone tells you the actual name and suddenly all is very simple. CCD Red Grade - Practices Follow the Boy Scouts Rule Root Cause Analysis - RCA Use a Version Control System Apply Simple Refactoring Pattern Reflect Daily Introduction to the principles and practices of Clean Code Developer - here: Red Grade As for the various ToDo's we commonly agreed that the Boy Scout Rule clearly is not limited to software development or IT administration but applies to daily life in general. Same for the root cause analysis, btw. We really had good stories with surprisingly endings and conclusions. A quick check about who is using a version control system brought more drive into the conversation. Not only that we had people that aren't using any VCS at all, we also had the 'classic' approach of backup folders and naming conventions as well as the VCS 'junkie' that has to use multiple systems at a time. Just for the records: Git and GitHub seem to be in favour of some of the attendees. Regarding the daily reflection at the end of the day we came up with an easy solution: Wrap it up as a blog entry! Certifications in IT This is kind of a controversy in IT in general. Is it interesting to go for certifications or are they completely obsolete? What are the possibilities to get certified? What are the options we have in Mauritius? How would certificates stand compared to other educational tracks like Computer Science or Web Design. The ratio between craftsmen with certifications like MCP, MSTS, CCNA or LPI versus the ones without wasn't in favour for the first group but there was a high interest in the topic itself and some were really surprised to hear that exam preparations are completely free available online including temporarily voucher codes for either discounts or completely free exams. Furthermore, we discussed possible options on forming so-called study groups on a specific certificates and organising more frequent meetups in order to learn together. Taking into consideration that we have sponsored access to the video course material of Pluralsight (and now PeepCode as well as TrainSignal), we might give it a try by the end of the year. Current favourites are LPIC Level 1 and one of the Microsoft exams 40-78x. Feedback and ideas for the MSCC The closing conversations and discussions about how the MSCC is recently doing, what are the possibilities and what's (hopefully) going to happen in the future were really fertile and I made a couple of mental bullet points which I'm looking forward to tackle down together with orher craftsmen. Eventually, it might be a good option to elaborate on some issues during our weekly Code & Coffee sessions one Wednesday morning. Active discussion on various IT topics like certifications (LPI, MCP, CCNA, etc) and sharing experience Finally, we made it till the end of the planned time. Well, actually the talk was still on and we continued even after 16:00hrs. Unfortunately, we (the children and I) had to leave for evening activities. My resume of the day... It was great to have 15 craftsmen in one room. There are hundreds of IT geeks out there in Mauritius, and as Mauritius Software Craftsmanship Community we still have a lot of work to do to pass on the message to some more key players and companies. Currently, it seems that we are able to attract a good number of students in Computer Science... but we have a lot more to offer, even or especially for IT people on the job. I'm already looking forward to our next Saturday meetup in the near future. PS: Meetup pictures are courtesy of Nirvan Pagooah. Thanks for sharing...

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  • array and array_view from amp.h

    - by Daniel Moth
    This is a very long post, but it also covers what are probably the classes (well, array_view at least) that you will use the most with C++ AMP, so I hope you enjoy it! Overview The concurrency::array and concurrency::array_view template classes represent multi-dimensional data of type T, of N dimensions, specified at compile time (and you can later access the number of dimensions via the rank property). If N is not specified, it is assumed that it is 1 (i.e. single-dimensional case). They are rectangular (not jagged). The difference between them is that array is a container of data, whereas array_view is a wrapper of a container of data. So in that respect, array behaves like an STL container, whereas the closest thing an array_view behaves like is an STL iterator (albeit with random access and allowing you to view more than one element at a time!). The data in the array (whether provided at creation time or added later) resides on an accelerator (which is specified at creation time either explicitly by the developer, or set to the default accelerator at creation time by the runtime) and is laid out contiguously in memory. The data provided to the array_view is not stored by/in the array_view, because the array_view is simply a view over the real source (which can reside on the CPU or other accelerator). The underlying data is copied on demand to wherever the array_view is accessed. Elements which differ by one in the least significant dimension of the array_view are adjacent in memory. array objects must be captured by reference into the lambda you pass to the parallel_for_each call, whereas array_view objects must be captured by value (into the lambda you pass to the parallel_for_each call). Creating array and array_view objects and relevant properties You can create array_view objects from other array_view objects of the same rank and element type (shallow copy, also possible via assignment operator) so they point to the same underlying data, and you can also create array_view objects over array objects of the same rank and element type e.g.   array_view<int,3> a(b); // b can be another array or array_view of ints with rank=3 Note: Unlike the constructors above which can be called anywhere, the ones in the rest of this section can only be called from CPU code. You can create array objects from other array objects of the same rank and element type (copy and move constructors) and from other array_view objects, e.g.   array<float,2> a(b); // b can be another array or array_view of floats with rank=2 To create an array from scratch, you need to at least specify an extent object, e.g. array<int,3> a(myExtent);. Note that instead of an explicit extent object, there are convenience overloads when N<=3 so you can specify 1-, 2-, 3- integers (dependent on the array's rank) and thus have the extent created for you under the covers. At any point, you can access the array's extent thought the extent property. The exact same thing applies to array_view (extent as constructor parameters, incl. convenience overloads, and property). While passing only an extent object to create an array is enough (it means that the array will be written to later), it is not enough for the array_view case which must always wrap over some other container (on which it relies for storage space and actual content). So in addition to the extent object (that describes the shape you'd like to be viewing/accessing that data through), to create an array_view from another container (e.g. std::vector) you must pass in the container itself (which must expose .data() and a .size() methods, e.g. like std::array does), e.g.   array_view<int,2> aaa(myExtent, myContainerOfInts); Similarly, you can create an array_view from a raw pointer of data plus an extent object. Back to the array case, to optionally initialize the array with data, you can pass an iterator pointing to the start (and optionally one pointing to the end of the source container) e.g.   array<double,1> a(5, myVector.begin(), myVector.end()); We saw that arrays are bound to an accelerator at creation time, so in case you don’t want the C++ AMP runtime to assign the array to the default accelerator, all array constructors have overloads that let you pass an accelerator_view object, which you can later access via the accelerator_view property. Note that at the point of initializing an array with data, a synchronous copy of the data takes place to the accelerator, and then to copy any data back we'll see that an explicit copy call is required. This does not happen with the array_view where copying is on demand... refresh and synchronize on array_view Note that in the previous section on constructors, unlike the array case, there was no overload that accepted an accelerator_view for array_view. That is because the array_view is simply a wrapper, so the allocation of the data has already taken place before you created the array_view. When you capture an array_view variable in your call to parallel_for_each, the copy of data between the non-CPU accelerator and the CPU takes place on demand (i.e. it is implicit, versus the explicit copy that has to happen with the array). There are some subtleties to the on-demand-copying that we cover next. The assumption when using an array_view is that you will continue to access the data through the array_view, and not through the original underlying source, e.g. the pointer to the data that you passed to the array_view's constructor. So if you modify the data through the array_view on the GPU, the original pointer on the CPU will not "know" that, unless one of two things happen: you access the data through the array_view on the CPU side, i.e. using indexing that we cover below you explicitly call the array_view's synchronize method on the CPU (this also gets called in the array_view's destructor for you) Conversely, if you make a change to the underlying data through the original source (e.g. the pointer), the array_view will not "know" about those changes, unless you call its refresh method. Finally, note that if you create an array_view of const T, then the data is copied to the accelerator on demand, but it does not get copied back, e.g.   array_view<const double, 5> myArrView(…); // myArrView will not get copied back from GPU There is also a similar mechanism to achieve the reverse, i.e. not to copy the data of an array_view to the GPU. copy_to, data, and global copy/copy_async functions Both array and array_view expose two copy_to overloads that allow copying them to another array, or to another array_view, and these operations can also be achieved with assignment (via the = operator overloads). Also both array and array_view expose a data method, to get a raw pointer to the underlying data of the array or array_view, e.g. float* f = myArr.data();. Note that for array_view, this only works when the rank is equal to 1, due to the data only being contiguous in one dimension as covered in the overview section. Finally, there are a bunch of global concurrency::copy functions returning void (and corresponding concurrency::copy_async functions returning a future) that allow copying between arrays and array_views and iterators etc. Just browse intellisense or amp.h directly for the full set. Note that for array, all copying described throughout this post is deep copying, as per other STL container expectations. You can never have two arrays point to the same data. indexing into array and array_view plus projection Reading or writing data elements of an array is only legal when the code executes on the same accelerator as where the array was bound to. In the array_view case, you can read/write on any accelerator, not just the one where the original data resides, and the data gets copied for you on demand. In both cases, the way you read and write individual elements is via indexing as described next. To access (or set the value of) an element, you can index into it by passing it an index object via the subscript operator. Furthermore, if the rank is 3 or less, you can use the function ( ) operator to pass integer values instead of having to use an index object. e.g. array<float,2> arr(someExtent, someIterator); //or array_view<float,2> arr(someExtent, someContainer); index<2> idx(5,4); float f1 = arr[idx]; float f2 = arr(5,4); //f2 ==f1 //and the reverse for assigning, e.g. arr(idx[0], 7) = 6.9; Note that for both array and array_view, regardless of rank, you can also pass a single integer to the subscript operator which results in a projection of the data, and (for both array and array_view) you get back an array_view of rank N-1 (or if the rank was 1, you get back just the element at that location). Not Covered In this already very long post, I am not going to cover three very cool methods (and related overloads) that both array and array_view expose: view_as, section, reinterpret_as. We'll revisit those at some point in the future, probably on the team blog. Comments about this post by Daniel Moth welcome at the original blog.

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  • Agile Testing Days 2012 – Day 2 – Learn through disagreement

    - by Chris George
    I think I was in the right place! During Day 1 I kept on reading tweets about Lean Coffee that has happened earlier that morning. It intrigued me and I figured in for a penny in for a pound, and set my alarm for 6:45am. Following the award night the night before, it was _really_ hard getting up when it went off, but I did and after a very early breakfast, set off for the 10 min walk to the Dorint. With Lean Coffee due to start at 07:30, I arrived at the hotel and made my way to one of the hotel bars. I soon realised I was in the right place as although the bar was empty, there was a table with post-it’s and pens! This MUST be the place! The premise of Lean Coffee is to have several small timeboxed discussions. Everyone writes down what they would like to discuss on post-its that are then briefly explained and submitted to the pile. Once everyone is done, the group dot-votes on the topics. The topics are then sorted by the dot vote counts and the discussions begin. Each discussion had 8 mins to start with, which meant it prevented the discussions getting off topic too much. After the time elapsed, the group had a vote whether to extend the discussion by a further 4 mins or move on. Several discussion were had around training, soft skills etc. The conversations were really interesting and there were quite a few good ideas. Overall it was a very enjoyable experience, certainly worth the early start! Make Melly Happy Following Lean Coffee was real coffee, and much needed that was! The first keynote of the day was “Let’s help Melly (Changing Work into Life)”by Jurgen Appelo. Draw lines to track happiness This was a very interesting presentation, and set the day nicely. The theme to the keynote was projects are about the people, more-so than the actual tasks. So he started by showing a photo of an employee ‘Melly’ who looked happy enough. He then stated that she looked happy but actually hated her job. In fact 50% of Americans hate their jobs. He went on to say that the world over 50% of people hate Americans their jobs. Jurgen talked about many ways to reduce the feedback cycle, not only of the project, but of the people management. Ideas such as Happiness doors, happiness tracking (drawing lines on a wall indicating your happiness for that day), kudo boxes (to compliment a colleague for good work). All of these (and more) ideas stimulate conversation amongst the team, lead to early detection of issues and investigation of solutions. I’ve massively simplified Jurgen’s keynote and have certainly not done it justice, so I will post a link to the video once it’s available. Following more coffee, the next talk was “How releasing faster changes testing” by Alexander Schwartz. This is a topic very close to our hearts at the moment, so I was eager to find out any juicy morsels that could help us achieve more frequent releases, and Alex did not disappoint. He started off by confirming something that I have been a firm believer in for a number of years now; adding more people can do more harm than good when trying to release. This is for a number of reasons, but just adding new people to a team at such a critical time can be more of a drain on resources than they add. The alternative is to have the whole team have shared responsibility for faster delivery. So the whole team is responsible for quality and testing. Obviously you will have the test engineers on the project who have the specialist skills, but there is no reason that the entire team cannot do exploratory testing on the product. This links nicely with the Developer Exploratory testing presented by Sigge on Day 1, and certainly something that my team are really striving towards. Focus on cycle time, so what can be done to reduce the time between dev cycles, release cycles. What’s stops a release, what delays a release? all good solid questions that can be answered. Alex suggested that perhaps the product doesn’t need to be fully tested. Doing less testing will reduce the cycle time therefore get the release out faster. He suggested a risk-based approach to planning what testing needs to happen. Reducing testing could have an impact on revenue if it causes harm to customers, so test the ‘right stuff’! Determine a set of tests that are ‘face saving’ or ‘smoke’ tests. These tests cover the core functionality of the product and aim to prevent major embarrassment if these areas were to fail! Amongst many other very good points, Alex suggested that a good approach would be to release after every new feature is added. So do a bit of work -> release, do some more work -> release. By releasing small increments of work, the impact on the customer of bugs being introduced is reduced. Red Pill, Blue Pill The second keynote of the day was “Adaptation and improvisation – but your weakness is not your technique” by Markus Gartner and proved to be another very good presentation. It started off quoting lines from the Matrix which relate to adapting, improvising, realisation and mastery. It has alot of nerds in the room smiling! Markus went on to explain how through deliberate practice ( and a lot of it!) you can achieve mastery, but then you never stop learning. Through methods such as code retreats, testing dojos, workshops you can continually improve and learn. The code retreat idea was one that interested me. It involved pairing to write an automated test for, say, 45 mins, they deleting all the code, finding a different partner and writing the same test again! This is another keynote where the video will speak louder than anything I can write here! Markus did elaborate on something that Lisa and Janet had touched on yesterday whilst busting the myth that “Testers Must Code”. Whilst it is true that to be a tester, you don’t need to code, it is becoming more common that there is this crossover happening where more testers are coding and more programmers are testing. Markus made a special distinction between programmers and developers as testers develop tests code so this helped to make that clear. “Extending Continuous Integration and TDD with Continuous Testing” by Jason Ayers was my next talk after lunch. We already do CI and a bit of TDD on my project team so I was interested to see what this continuous testing thing was all about and whether it would actually work for us. At the start of the presentation I was of the opinion that it just would not work for us because our tests are too slow, and that would be the case for many people. Jason started off by setting the scene and saying that those doing TDD spend between 10-15% of their time waiting for tests to run. This can be reduced by testing less often, reducing the test time but this then increases the risk of introduced bugs not being spotted quickly. Therefore, in comes Continuous Testing (CT). CT systems run your unit tests whenever you save some code and runs them in the background so you can continue working. This is a really nice idea, but to do this, your tests must be fast, independent and reliable. The latter two should be the case anyway, and the first is ideal, but hard! Jason makes several suggestions to make tests fast. Firstly keep the scope of the test small, secondly spin off any expensive tests into a suite which is run, perhaps, overnight or outside of the CT system at any rate. So this started to change my mind, perhaps we could re-engineer our tests, and continuously run the quick ones to give an element of coverage. This talk was very interesting and I’ve already tried a couple of the tools mentioned on our product (Mighty Moose and NCrunch). Sadly due to the way our solution is built, it currently doesn’t work, but we will look at whether we can make this work because this has the potential to be a mini-game-changer for us. Using the wrong data Gojko’s Hierarchy of Quality The final keynote of the day was “Reinventing software quality” by Gojko Adzic. He opened the talk with the statement “We’ve got quality wrong because we are using the wrong data”! Gojko then went on to explain that we should judge a bug by whether the customer cares about it, not by whether we think it’s important. Why spend time fixing issues that the customer just wouldn’t care about and releasing months later because of this? Surely it’s better to release now and get customer feedback? This was another reference to the idea of how it’s better to build the right thing wrong than the wrong thing right. Get feedback early to make sure you’re making the right thing. Gojko then showed something which was very analogous to Maslow’s heirachy of needs. Successful – does it contribute to the business? Useful – does it do what the user wants Usable – does it do what it’s supposed to without breaking Performant/Secure – is it secure/is the performance acceptable Deployable Functionally ok – can it be deployed without breaking? He then explained that User Stories should focus on change. In other words they should focus on the users needs, not the users process. Describe what the change will be, how that change will happen then measure it! Networking and Beer Following the day’s closing keynote, there were drinks and nibble for the ‘Networking’ evening. This was a great opportunity to talk to people. I find approaching strangers very uncomfortable but once again, when in Rome! Pete Walen and I had a long conversation about only fixing issues that the customer cares about versus fixing issues that make you proud of your software! Without saying much, and asking the right questions, Pete made me re-evaluate my thoughts on the matter. Clever, very clever!  Oh and he ‘bought’ me a beer! My Takeaway Triple from Day 2: release small and release often to minimize issues creeping in and get faster feedback from ‘the real world’ Focus on issues that the customers care about, not what we think is important It’s okay to disagree with someone, even if they are well respected agile testing gurus, that’s how discussion and learning happens!  

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  • OK - What now? How do we become a Social Business?

    - by Michael Snow
    We hope that those of you that attended yesterday's Webcast with Brian Solis enjoyed Brian's discussion with Christian Finn for our last Webcast of the season for the Oracle Social Business Thought Leaders Series.  For those of you that may have missed the webcast or were stuck at a company holiday party - you'll be glad to hear that the webcast will be available On-Demand starting later today (12/14/12). And any of you who'd like to listen to a quick but informative podcast with Brian - can listen to that here. Some of you may still be left with questions about how to get from point A to point B and even more confused than when you started thinking about this new world of Digital Darwinism. The post below, grabbed from an abundance of great thought leadership prose on Brian's blog may help you frame the path you need to start walking sooner versus later to stay off of the endangered species list.  As you explore your path forward, please keep Oracle in mind - we do offer a wide range of solutions to help your organization 12.00 Normal 0 false false false EN-US X-NONE X-NONE MicrosoftInternetExplorer4 /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin:0in; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-fareast-font-family:"Times New Roman"; mso-fareast-theme-font:minor-fareast; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:"Times New Roman"; mso-bidi-theme-font:minor-bidi;} optimize the engagement for your customers, employees and partners. The Path from a Social Brand to a Social Business Brian Solis Originally posted May 2, 2012 I’ve been a long-time supporter of MediaTemple’s (MT)Residence program along with Gary Vaynerchuk, Neil Patel, and many others whom I respect. I wanted to share my “7 questions to answer to become a social business” with you here.. Social Media is pervasive and is becoming the new normal in corporate marketing. Brands who get this right are starting to build their own media networks rich with customer connections numbering in the millions. Right now, Coca-Cola has over 34 million fans on Facebook, but they’re hardly alone. Disney follows just behind with 29 million fans, Starbucks boasts 25 million, and Oreo, Red Bull, and Converse play host to over 20 million fans. If we were to look at other networks such as Twitter and Youtube, we would see a recurring theme. People are connecting en masse with the businesses they support and new media represents the ability to cultivate consumer relationships in ways not possible with traditional earned or paid media. Sounds great right? This might sound abrupt, but the truth is that we’re hardly realizing the potential of what lies before us. Everything begins with understanding not just how other brands are marketing themselves in social media, but also seeing what they’re not doing and envisioning what’s possible. We’re already approaching the first of many crossroads that new media will present. Do we take the path of a social brand or that of a social business? What’s the difference? A social brand is just that, a business that is remodeling or retrofitting its existing marketing practices to new media. A social business is something altogether different as it embraces introspection and extrospection to reevaluate internal and external processes, systems, and opportunities to transform into a living, breathing entity that adapts to market conditions and opportunities. It’s a tough decision to make right now especially at a time when all we read about is how much success many businesses are finding without having to answer this very question. With all of the newfound success in social networks, the truth is that we’re only just beginning to learn what’s possible and that’s where you come in. When compared to the investment in time and resources across the board, social media represents only a small part of the mix. But with your help, that’s all about to change. The CMO Survey, an organization that disseminates the opinions of top marketers in order to predict the future of markets, recently published a report that gave credence to the fact that social media is taking off. One of the most profound takeaways from the report was this gem; “The “like button” [in Facebook] packs more customer-acquisition punch than other demand-generating activities.” With insights like this, it’s easy to see why the race to social is becoming heated. The report also highlighted exactly where social fits in the marketing mix today and as you can see, despite all of the hype, it’s not a dominant focus yet. As of August 2011, the percentage of overall marketing budgets dedicated to social media hovered at around 7%. However, in 2012 the investment in social media will climb to 10%. And, in five years, social media is expected to represent almost 18% of the total marketing budget. Think about that for a moment. In 2016, social media will only represent 18%? Queue the sound of a record scratching here. With businesses finding success in social networks, why are businesses failing to realize the true opportunity brought forth by the ability to listen to, connect with, and engage with customers? While there’s value in earning views, driving traffic, and building connections through the 3F’s (friends, fans and followers), success isn’t just defined simply by what really amounts to low-hanging fruit. The truth is that businesses cannot measure what it is they don’t know to value. As a result, innovation in new engagement initiatives is stifled because we’re applying dated or inflexible frameworks to new paradigms. Social media isn’t owned by marketing, but instead the entire organization. This changes everything and makes your role so much more important. It’s up to you to learn how to think outside of the proverbial social media box to see what others don’t, the ability to improve customers experiences through the evolution of a social brand into a social business. Doing so will translate customer insights from what they do and don’t share in social networks into better products, services, and processes. See, customers want something more from their favorite businesses than creative campaigns, viral content, and everyday dialogue in social networks. Customers want to be heard and they want to know that you’re listening. How businesses use social media must remind them that they’re more than just an audience, consumer, or a conduit to “trigger” a desired social effect. Herein lies both the challenge and opportunity of social media. It’s bigger than marketing. It’s also bigger than customer service. It’s about building relationships with customers that improve experiences and more importantly, teaches businesses how to re-imagine products and internal processes to better adapt to potential crises and seize new opportunities. When it comes down to it, Twitter, Facebook, Youtube, Foursquare, are all channels for listening, learning, and engaging. It’s what you do within each channel that builds a community around your brand. And, at the end of the day, the value of the community you build counts for everything. It’s important to understand that we cannot assume that these networks simply exist for people to lineup for our marketing messages or promotional campaigns. Nor can we assume that they’re reeling in anticipation for simple dialogue. They want value. They want recognition. They want access to exclusive information and offers. They need direction, answers and resolution. What we’re talking about here is the multidimensional makeup of consumers and how a one-sided approach to social media forces the needs for social media to expand beyond traditional marketing to socialize the various departments, lines of business, and functions to engage based on the nature of the situation or opportunity. In the same CMO study, it was revealed that marketers believe that social media has a long way to go toward integrating into the overall company strategy. On a scale of 1-7, with one being “not integrated at all” and seven being “very integrated,” 22% chose “one.” Critical functions such as service, HR, sales, R&D, product marketing and development, IR, CSR, etc. are either not engaged or are operating social media within a silo disconnected from other efforts or possibilities. The problem is that customers don’t view a company by silo, instead they see one company, one brand, and their experience in social media forms an impression that eventually contributes to their view of your brand. The first step here is to understand business priorities and objectives to assess how social media can be additive in achieving these goals. Additionally, surveying the landscape to determine other areas of interest as its specifically related to your business. • Are customers seeking help or direction? • Who are your most valuable customers and what are they sharing? • How can you use social media to acquire and retain customers? - What ideas are circulating and how can you harness user generated activity and content to innovate or adapt to better meet the needs of customers? - How can you broaden a single customer view to recognize the varying needs of customers and how your organization can organize around each circumstance? - What insights exist based on how consumers are interacting with one another? How can this intelligence inform marketing, service, products and other important business initiatives? - How can your business extend their current efforts to deliver better customer experiences and in turn more effectively unit internal collaboration and communication? Customer demands far exceed the capabilities of the marketing department. While creating a social brand is a necessary endeavor, building a social business is an investment in customer relevance now and over time. Beyond relevance, a social business fosters a culture of change that unites employees and customers and sets a foundation for meaningful and beneficial relationships. Innovation, communication, and creativity are the natural byproducts of engagement and transformation. As a social brand, we are competing for the moment. As a social business, we are competing the future in all that we do today.

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  • Matrix Multiplication with C++ AMP

    - by Daniel Moth
    As part of our API tour of C++ AMP, we looked recently at parallel_for_each. I ended that post by saying we would revisit parallel_for_each after introducing array and array_view. Now is the time, so this is part 2 of parallel_for_each, and also a post that brings together everything we've seen until now. The code for serial and accelerated Consider a naïve (or brute force) serial implementation of matrix multiplication  0: void MatrixMultiplySerial(std::vector<float>& vC, const std::vector<float>& vA, const std::vector<float>& vB, int M, int N, int W) 1: { 2: for (int row = 0; row < M; row++) 3: { 4: for (int col = 0; col < N; col++) 5: { 6: float sum = 0.0f; 7: for(int i = 0; i < W; i++) 8: sum += vA[row * W + i] * vB[i * N + col]; 9: vC[row * N + col] = sum; 10: } 11: } 12: } We notice that each loop iteration is independent from each other and so can be parallelized. If in addition we have really large amounts of data, then this is a good candidate to offload to an accelerator. First, I'll just show you an example of what that code may look like with C++ AMP, and then we'll analyze it. It is assumed that you included at the top of your file #include <amp.h> 13: void MatrixMultiplySimple(std::vector<float>& vC, const std::vector<float>& vA, const std::vector<float>& vB, int M, int N, int W) 14: { 15: concurrency::array_view<const float,2> a(M, W, vA); 16: concurrency::array_view<const float,2> b(W, N, vB); 17: concurrency::array_view<concurrency::writeonly<float>,2> c(M, N, vC); 18: concurrency::parallel_for_each(c.grid, 19: [=](concurrency::index<2> idx) restrict(direct3d) { 20: int row = idx[0]; int col = idx[1]; 21: float sum = 0.0f; 22: for(int i = 0; i < W; i++) 23: sum += a(row, i) * b(i, col); 24: c[idx] = sum; 25: }); 26: } First a visual comparison, just for fun: The beginning and end is the same, i.e. lines 0,1,12 are identical to lines 13,14,26. The double nested loop (lines 2,3,4,5 and 10,11) has been transformed into a parallel_for_each call (18,19,20 and 25). The core algorithm (lines 6,7,8,9) is essentially the same (lines 21,22,23,24). We have extra lines in the C++ AMP version (15,16,17). Now let's dig in deeper. Using array_view and extent When we decided to convert this function to run on an accelerator, we knew we couldn't use the std::vector objects in the restrict(direct3d) function. So we had a choice of copying the data to the the concurrency::array<T,N> object, or wrapping the vector container (and hence its data) with a concurrency::array_view<T,N> object from amp.h – here we used the latter (lines 15,16,17). Now we can access the same data through the array_view objects (a and b) instead of the vector objects (vA and vB), and the added benefit is that we can capture the array_view objects in the lambda (lines 19-25) that we pass to the parallel_for_each call (line 18) and the data will get copied on demand for us to the accelerator. Note that line 15 (and ditto for 16 and 17) could have been written as two lines instead of one: extent<2> e(M, W); array_view<const float, 2> a(e, vA); In other words, we could have explicitly created the extent object instead of letting the array_view create it for us under the covers through the constructor overload we chose. The benefit of the extent object in this instance is that we can express that the data is indeed two dimensional, i.e a matrix. When we were using a vector object we could not do that, and instead we had to track via additional unrelated variables the dimensions of the matrix (i.e. with the integers M and W) – aren't you loving C++ AMP already? Note that the const before the float when creating a and b, will result in the underling data only being copied to the accelerator and not be copied back – a nice optimization. A similar thing is happening on line 17 when creating array_view c, where we have indicated that we do not need to copy the data to the accelerator, only copy it back. The kernel dispatch On line 18 we make the call to the C++ AMP entry point (parallel_for_each) to invoke our parallel loop or, as some may say, dispatch our kernel. The first argument we need to pass describes how many threads we want for this computation. For this algorithm we decided that we want exactly the same number of threads as the number of elements in the output matrix, i.e. in array_view c which will eventually update the vector vC. So each thread will compute exactly one result. Since the elements in c are organized in a 2-dimensional manner we can organize our threads in a two-dimensional manner too. We don't have to think too much about how to create the first argument (a grid) since the array_view object helpfully exposes that as a property. Note that instead of c.grid we could have written grid<2>(c.extent) or grid<2>(extent<2>(M, N)) – the result is the same in that we have specified M*N threads to execute our lambda. The second argument is a restrict(direct3d) lambda that accepts an index object. Since we elected to use a two-dimensional extent as the first argument of parallel_for_each, the index will also be two-dimensional and as covered in the previous posts it represents the thread ID, which in our case maps perfectly to the index of each element in the resulting array_view. The kernel itself The lambda body (lines 20-24), or as some may say, the kernel, is the code that will actually execute on the accelerator. It will be called by M*N threads and we can use those threads to index into the two input array_views (a,b) and write results into the output array_view ( c ). The four lines (21-24) are essentially identical to the four lines of the serial algorithm (6-9). The only difference is how we index into a,b,c versus how we index into vA,vB,vC. The code we wrote with C++ AMP is much nicer in its indexing, because the dimensionality is a first class concept, so you don't have to do funny arithmetic calculating the index of where the next row starts, which you have to do when working with vectors directly (since they store all the data in a flat manner). I skipped over describing line 20. Note that we didn't really need to read the two components of the index into temporary local variables. This mostly reflects my personal choice, in some algorithms to break down the index into local variables with names that make sense for the algorithm, i.e. in this case row and col. In other cases it may i,j,k or x,y,z, or M,N or whatever. Also note that we could have written line 24 as: c(idx[0], idx[1])=sum  or  c(row, col)=sum instead of the simpler c[idx]=sum Targeting a specific accelerator Imagine that we had more than one hardware accelerator on a system and we wanted to pick a specific one to execute this parallel loop on. So there would be some code like this anywhere before line 18: vector<accelerator> accs = MyFunctionThatChoosesSuitableAccelerators(); accelerator acc = accs[0]; …and then we would modify line 18 so we would be calling another overload of parallel_for_each that accepts an accelerator_view as the first argument, so it would become: concurrency::parallel_for_each(acc.default_view, c.grid, ...and the rest of your code remains the same… how simple is that? Comments about this post by Daniel Moth welcome at the original blog.

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  • Why does Gnumake from parent directory behave differently?

    - by WilliamKF
    I am stumped as to why when I do a gnumake from the parent directory it behaves incorrectly, whereas, if I cd to the subdirectory and do gnumake it works correctly. In the parent makefile, I have a rule like this: .PHONY: zlib-1.2.5 zlib-1.2.5: @ echo Issuing $(MAKE) in $@ ... pushd zlib-1.2.5; make; popd Which gives different result than doing the same from the toplevel pushd zlib-1.2.5; make; popd There is a something from the parent makefile that is making its way into the subdirectory makefile and causing it to behave incorrectly, but I don't know how to find it. The symptom I see is that the subdirectory config generated makefile rule for zlib misses the dependencies and I get this result going straight to the ar without generating the .o(s) first: cd ~/src; make zlib-1.2.5 CPPFLAGS_AUTO = < > Issuing make in zlib-1.2.5 ... pushd zlib-1.2.5; make; popd ~/src/zlib-1.2.5 ~/src make[1]: Entering directory `/disk2/user/src/zlib-1.2.5' ar rc libz.a adler32.o compress.o crc32.o deflate.o gzclose.o gzlib.o gzread.o gzwrite.o infback.o inffast.o inflate.o inftrees.o trees.o uncompr.o zutil.o ar: adler32.o: No such file or directory make[1]: *** [libz.a] Error 1 gcc -shared -Wl,-soname,libz.so.1,--version-script,zlib.map -O3 -fPIC -D_LARGEFILE64_SOURCE=1 -o libz.so.1.2.5 adler32.lo compress.lo crc32.lo deflate.lo gzclose.lo gzlib.lo gzread.lo gzwrite.lo infback.lo inffast.lo inflate.lo inftrees.lo trees.lo uncompr.lo zutil.lo -lc -L. libz.a gcc: adler32.lo: No such file or directory gcc: compress.lo: No such file or directory gcc: crc32.lo: No such file or directory gcc: deflate.lo: No such file or directory [...] make[1]: *** [libz.so.1.2.5] Error 1 make[1]: Target `all' not remade because of errors. make[1]: Leaving directory `/disk2/user/src/zlib-1.2.5' ~/src Versus from the zlib directory where it works correctly: cd ~/src/zlib-1.2.5; make gcc -O3 -D_LARGEFILE64_SOURCE=1 -c -o example.o example.c gcc -O3 -D_LARGEFILE64_SOURCE=1 -c -o adler32.o adler32.c gcc -O3 -D_LARGEFILE64_SOURCE=1 -c -o compress.o compress.c gcc -O3 -D_LARGEFILE64_SOURCE=1 -c -o crc32.o crc32.c [...] gcc -O3 -D_LARGEFILE64_SOURCE=1 -c -o zutil.o zutil.c ar rc libz.a adler32.o compress.o crc32.o deflate.o gzclose.o gzlib.o gzread.o gzwrite.o infback.o inffast.o inflate.o inftrees.o trees.o uncompr.o zutil.o (ranlib libz.a || true) >/dev/null 2>&1 gcc -O3 -D_LARGEFILE64_SOURCE=1 -o example example.o -L. libz.a gcc -O3 -D_LARGEFILE64_SOURCE=1 -c -o minigzip.o minigzip.c gcc -O3 -D_LARGEFILE64_SOURCE=1 -o minigzip minigzip.o -L. libz.a mkdir objs 2>/dev/null || test -d objs gcc -O3 -fPIC -D_LARGEFILE64_SOURCE=1 -DPIC -c -o objs/adler32.o adler32.c mv objs/adler32.o adler32.lo mkdir objs 2>/dev/null || test -d objs gcc -O3 -fPIC -D_LARGEFILE64_SOURCE=1 -DPIC -c -o objs/compress.o compress.c mv objs/compress.o compress.lo [...] mkdir objs 2>/dev/null || test -d objs gcc -O3 -fPIC -D_LARGEFILE64_SOURCE=1 -DPIC -c -o objs/zutil.o zutil.c mv objs/zutil.o zutil.lo gcc -shared -Wl,-soname,libz.so.1,--version-script,zlib.map -O3 -fPIC -D_LARGEFILE64_SOURCE=1 -o libz.so.1.2.5 adler32.lo compress.lo crc32.lo deflate.lo gzclose.lo gzlib.lo gzread.lo gzwrite.lo infback.lo inffast.lo inflate.lo inftrees.lo trees.lo uncompr.lo zutil.lo -lc -L. libz.a rm -f libz.so libz.so.1 ln -s libz.so.1.2.5 libz.so ln -s libz.so.1.2.5 libz.so.1 rmdir objs gcc -O3 -D_LARGEFILE64_SOURCE=1 -o examplesh example.o -L. libz.so.1.2.5 gcc -O3 -D_LARGEFILE64_SOURCE=1 -o minigzipsh minigzip.o -L. libz.so.1.2.5 gcc -O3 -D_LARGEFILE64_SOURCE=1 -o example64 example64.o -L. libz.a gcc -O3 -D_LARGEFILE64_SOURCE=1 -o minigzip64 minigzip64.o -L. libz.a

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  • PHP framework question

    - by iconiK
    I'm currently working on a browser-based MMO and have chosen the LAMP stack because of the extremely low cost to start with in production (versus Windows + IIS + ASP.NET/C# + SQL Server, even though I have MSDN Universal). However I will need a PHP framework for this as it's no easy task. I am not restricted by anything other than the ability to run on Linux, as I will use a dedicated cloud hosting solution (and a VMWare image for development) and can configure it as needed. In no specific order: It has to be easily scalable; this is crucial. If the game becomes a steady success it will eventually outgrow the server beyond what the host provides and would have to be moved to several load-balanced servers. It is crucial that this can be done with minimum effort. I do know this might require following strict conventions, so if you know of any for your suggested framework please explain what would be needed. It has to provide modules for all the core tasks: authentication, ACL, database access, MVC, and so on. One or two missing modules are fine, as long as they can easily be written and integrated. It should support internationalization. I think there is no excuse for any web framework not to provide means of translating the application and switching between languages without a lot of effort from the programmer. Must have very good community support and preferably commercial support as well. Yes, I do know QCodo/QCubed is so nice, but it is not mature enough for this task. Smooth AJAX support is required. Whether the framework comes with AJAX-capable widgets or has an easy way of adding AJAX is not relevant, as long as AJAX is easily doable. I plan to use jQuery + Dojo or one of them alone - not exactly sure. Auto-magically doing stuff when it improves readability and relieves a lot of effort would be especially nice if it is generally reliable and does not interfere with other requirements. This seems to be the case of CakePHP. I have read a lot of comparisons and I know it's a really hot debate. The general answer is "try and see for yourself what suits you". However, I can't say it is easy for this task and I'm calling for your experience with building applications with similar requirements. So far I'm tied up between Zend and CakePHP by the general criteria, however, all well-known frameworks offer the same functionality in some way or another with different approaches each with it's own advantages and disadvantages. Edits: I am kinda new to MVC, however, I am willing to learn it and I don't care if a framework is easier for those new to MVC. I have lots of time to learn MVC and any other architectures (or whatever they're called) you recommend. I will use Zend as a utility "framework", even though it's just a collection of libraries (some good ones though, as I have been told). Current PHP contenders are: CakePHP, Kohana, Zend alone.

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  • When should I use indexed arrays of OpenGL vertices?

    - by Tartley
    I'm trying to get a clear idea of when I should be using indexed arrays of OpenGL vertices, drawn with gl[Multi]DrawElements and the like, versus when I should simply use contiguous arrays of vertices, drawn with gl[Multi]DrawArrays. (Update: The consensus in the replies I got is that one should always be using indexed vertices.) I have gone back and forth on this issue several times, so I'm going to outline my current understanding, in the hopes someone can either tell me I'm now finally more or less correct, or else point out where my remaining misunderstandings are. Specifically, I have three conclusions, in bold. Please correct them if they are wrong. One simple case is if my geometry consists of meshes to form curved surfaces. In this case, the vertices in the middle of the mesh will have identical attributes (position, normal, color, texture coord, etc) for every triangle which uses the vertex. This leads me to conclude that: 1. For geometry with few seams, indexed arrays are a big win. Follow rule 1 always, except: For geometry that is very 'blocky', in which every edge represents a seam, the benefit of indexed arrays is less obvious. To take a simple cube as an example, although each vertex is used in three different faces, we can't share vertices between them, because for a single vertex, the surface normals (and possible other things, like color and texture co-ord) will differ on each face. Hence we need to explicitly introduce redundant vertex positions into our array, so that the same position can be used several times with different normals, etc. This means that indexed arrays are of less use. e.g. When rendering a single face of a cube: 0 1 o---o |\ | | \ | | \| o---o 3 2 (this can be considered in isolation, because the seams between this face and all adjacent faces mean than none of these vertices can be shared between faces) if rendering using GL_TRIANGLE_FAN (or _STRIP), then each face of the cube can be rendered thus: verts = [v0, v1, v2, v3] colors = [c0, c0, c0, c0] normal = [n0, n0, n0, n0] Adding indices does not allow us to simplify this. From this I conclude that: 2. When rendering geometry which is all seams or mostly seams, when using GL_TRIANGLE_STRIP or _FAN, then I should never use indexed arrays, and should instead always use gl[Multi]DrawArrays. (Update: Replies indicate that this conclusion is wrong. Even though indices don't allow us to reduce the size of the arrays here, they should still be used because of other performance benefits, as discussed in the comments) The only exception to rule 2 is: When using GL_TRIANGLES (instead of strips or fans), then half of the vertices can still be re-used twice, with identical normals and colors, etc, because each cube face is rendered as two separate triangles. Again, for the same single cube face: 0 1 o---o |\ | | \ | | \| o---o 3 2 Without indices, using GL_TRIANGLES, the arrays would be something like: verts = [v0, v1, v2, v2, v3, v0] normals = [n0, n0, n0, n0, n0, n0] colors = [c0, c0, c0, c0, c0, c0] Since a vertex and a normal are often 3 floats each, and a color is often 3 bytes, that gives, for each cube face, about: verts = 6 * 3 floats = 18 floats normals = 6 * 3 floats = 18 floats colors = 6 * 3 bytes = 18 bytes = 36 floats and 18 bytes per cube face. (I understand the number of bytes might change if different types are used, the exact figures are just for illustration.) With indices, we can simplify this a little, giving: verts = [v0, v1, v2, v3] (4 * 3 = 12 floats) normals = [n0, n0, n0, n0] (4 * 3 = 12 floats) colors = [c0, c0, c0, c0] (4 * 3 = 12 bytes) indices = [0, 1, 2, 2, 3, 0] (6 shorts) = 24 floats + 12 bytes, and maybe 6 shorts, per cube face. See how in the latter case, vertices 0 and 2 are used twice, but only represented once in each of the verts, normals and colors arrays. This sounds like a small win for using indices, even in the extreme case of every single geometry edge being a seam. This leads me to conclude that: 3. When using GL_TRIANGLES, one should always use indexed arrays, even for geometry which is all seams. Please correct my conclusions in bold if they are wrong.

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  • Can't get my object to point at the mouse.

    - by melignus
    I'm using a combination of SDL and OpenGL in a sort of crash course project to teach myself how this all works. I'm really only interested in OpenGL as a way to use acceleration in 2D games so I just need this to work in a 2D plane. I have been having a lot of problems today with my current issue, I would like an object to point towards the mouse while the mouse button is clicked and then of course stay pointing in that direction after the mouse is lifted. void Square::handle_input() { //If a key was pressed if( event.type == SDL_KEYDOWN ) { //Adjust the velocity switch( event.key.keysym.sym ) { case SDLK_UP: upUp = false; yVel = -1; break; case SDLK_DOWN: downUp = false; yVel = 1; break; case SDLK_LEFT: leftUp = false; xVel = -1; break; case SDLK_RIGHT: rightUp = false; xVel = 1; break; case SDLK_w: wUp = false; sAng = 1; break; case SDLK_s: sUp = false; sAng = -1; break; } } //If a key was released else if( event.type == SDL_KEYUP ) { //Adjust the velocity switch( event.key.keysym.sym ) { case SDLK_UP: upUp = true; yVel = 0; break; case SDLK_DOWN: downUp = true; yVel = 0; break; case SDLK_LEFT: leftUp = true; xVel = 0; break; case SDLK_RIGHT: rightUp = true; xVel = 0; break; case SDLK_w: wUp = true; sAng = 0; break; case SDLK_s: sUp = true; sAng = 0; break; } } //If a mouse button was pressed if( event.type == SDL_MOUSEBUTTONDOWN ) { switch ( event.type ) { case SDL_MOUSEBUTTONDOWN: mouseUp = false; mousex == event.button.x; mousey == event.button.y; break; case SDL_MOUSEBUTTONUP: mouseUp = true; break; } } } And then this is called at the end of my Object::Move call which also handles x and y translation if (!mouseUp) { xVect = mousex - x; yVect = mousey - y; radAng = atan2 ( mousey - y, mousex - x ); sAng = radAng * 180 / 3.1415926l; } Right now when I click the object turns and faces down to the bottom left but then no longer changes direction. I'd really appreciate any help I could get here. I'm guessing there might be an issue here with state versus polled events but from all the tutorials that I've been through I was pretty sure I had fixed that. I've just hit a wall and I need some advice!

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  • Why don't I just build the whole web app in Javascript and Javascript HTML Templates?

    - by viatropos
    I'm getting to the point on an app where I need to start caching things, and it got me thinking... In some parts of the app, I render table rows (jqGrid, slickgrid, etc.) or fancy div rows (like in the New Twitter) by grabbing pure JSON and running it through something like Mustache, jquery.tmpl, etc. In other parts of the app, I just render the info in pure HTML (server-side HAML templates), and if there's searching/paginating, I just go to a new URL and load a new HTML page. Now the problem is in caching and maintainability. On one hand I'm thinking, if everything was built using Javascript HTML Templates, then my app would serve just an HTML layout/shell, and a bunch of JSON. If you look at the Facebook and Twitter HTML source, that's basically what they're doing (95% json/javascript, 5% html). This would make it so my app only needed to cache JSON (pages, actions, and/or records). Which means you'd hit the cache no matter if you were some remote api developer accessing a JSON api, or the strait web app. That is, I don't need 2 caches, one for the JSON, one for the HTML. That seems like it'd cut my cache store down in half, and streamline things a little bit. On the other hand, I'm thinking, from what I've seen/experienced, generating static HTML server-side, and caching that, seems to be much better performance wise cross-browser; you get the graphics instantly and don't have to wait that split-second for javascript to render it. StackOverflow seems to do everything in plain HTML, and you can tell... everything appears at once. Notice how though on twitter.com, the page is blank for .5-1 seconds, and the page chunks in: the javascript has to render the json. The downside with this is that, for anything dynamic (like endless scrolling, or grids), I'd have to create javascript templates anyway... so now I have server-side HAML templates, client-side javascript templates, and a lot more to cache. My question is, is there any consensus on how to approach this? What are the benefits and drawbacks from your experience of mixing the two versus going 100% with one over the other? Update: Some reasons that factor into why I haven't yet made the decision to go with 100% javascript templating are: Performance. Haven't formally tested, but from what I've seen, raw html renders faster and more fluidly than javascript-generated html cross-browser. Plus, I'm not sure how mobile devices handle dynamic html performance-wise. Testing. I have a lot of integration tests that work well with static HTML, so switching to javascript-only would require 1) more focused pure-javascript testing (jasmine), and 2) integrating javascript into capybara integration tests. This is just a matter of time and work, but it's probably significant. Maintenance. Getting rid of HAML. I love HAML, it's so easy to write, it prints pretty HTML... It makes code clean, it makes maintenance easy. Going with javascript, there's nothing as concise. SEO. I know google handles the ajax /#!/path, but haven't grasped how this will affect other search engines and how older browsers handle it. Seems like it'd require a significant setup.

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  • bulls and cows game -- programming algorithm(python)

    - by IcyFlame
    This is a simulation of the game Cows and Bulls with three digit numbers I am trying to get the number of cows and bulls between two numbers. One of which is generated by the computer and the other is guessed by the user. I have parsed the two numbers I have so that now I have two lists with three elements each and each element is one of the digits in the number. So: 237 will give the list [2,3,7]. And I make sure that the relative indices are maintained.the general pattern is:(hundreds, tens, units). And these two lists are stored in the two lists: machine and person. ALGORITHM 1 So, I wrote the following code, The most intuitive algorithm: cows and bulls are initialized to 0 before the start of this loop. for x in person: if x in machine: if machine.index(x) == person.index(x): bulls += 1 print x,' in correct place' else: print x,' in wrong place' cows += 1 And I started testing this with different type of numbers guessed by the computer. Quite randomly, I decided on 277. And I guessed 447. Here, I got the first clue that this algorithm may not work. I got 1 cow and 0 bulls. Whereas I should have got 1 bull and 1 cow. This is a table of outputs with the first algorithm: Guess Output Expected Output 447 0 bull, 1 cow 1 bull, 1 cow 477 2 bulls, 0 cows 2 bulls, 0 cows 777 0 bulls, 3 cows 2 bulls, 0 cows So obviously this algorithm was not working when there are repeated digits in the number randomly selected by the computer. I tried to understand why these errors are taking place, But I could not. I have tried a lot but I just could not see any mistake in the algorithm(probably because I wrote it!) ALGORITHM 2 On thinking about this for a few days I tried this: cows and bulls are initialized to 0 before the start of this loop. for x in range(3): for y in range(3): if x == y and machine[x] == person[y]: bulls += 1 if not (x == y) and machine[x] == person[y]: cows += 1 I was more hopeful about this one. But when I tested this, this is what I got: Guess Output Expected Output 447 1 bull, 1 cow 1 bull, 1 cow 477 2 bulls, 2 cows 2 bulls, 0 cows 777 2 bulls, 4 cows 2 bulls, 0 cows The mistake I am making is quite clear here, I understood that the numbers were being counted again and again. i.e.: 277 versus 477 When you count for bulls then the 2 bulls come up and thats alright. But when you count for cows: the 7 in 277 at units place is matched with the 7 in 477 in tens place and thus a cow is generated. the 7 in 277 at tens place is matched with the 7 in 477 in units place and thus a cow is generated.' Here the matching is exactly right as I have written the code as per that. But this is not what I want. And I have no idea whatsoever on what to do after this. Furthermore... I would like to stress that both the algorithms work perfectly, if there are no repeated digits in the number selected by the computer. Please help me with this issue. P.S.: I have been thinking about this for over a week, But I could not post a question earlier as my account was blocked(from asking questions) because I asked a foolish question. And did not delete it even though I got 2 downvotes immediately after posting the question.

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  • Inheritance Mapping Strategies with Entity Framework Code First CTP5: Part 3 – Table per Concrete Type (TPC) and Choosing Strategy Guidelines

    - by mortezam
    This is the third (and last) post in a series that explains different approaches to map an inheritance hierarchy with EF Code First. I've described these strategies in previous posts: Part 1 – Table per Hierarchy (TPH) Part 2 – Table per Type (TPT)In today’s blog post I am going to discuss Table per Concrete Type (TPC) which completes the inheritance mapping strategies supported by EF Code First. At the end of this post I will provide some guidelines to choose an inheritance strategy mainly based on what we've learned in this series. TPC and Entity Framework in the Past Table per Concrete type is somehow the simplest approach suggested, yet using TPC with EF is one of those concepts that has not been covered very well so far and I've seen in some resources that it was even discouraged. The reason for that is just because Entity Data Model Designer in VS2010 doesn't support TPC (even though the EF runtime does). That basically means if you are following EF's Database-First or Model-First approaches then configuring TPC requires manually writing XML in the EDMX file which is not considered to be a fun practice. Well, no more. You'll see that with Code First, creating TPC is perfectly possible with fluent API just like other strategies and you don't need to avoid TPC due to the lack of designer support as you would probably do in other EF approaches. Table per Concrete Type (TPC)In Table per Concrete type (aka Table per Concrete class) we use exactly one table for each (nonabstract) class. All properties of a class, including inherited properties, can be mapped to columns of this table, as shown in the following figure: As you can see, the SQL schema is not aware of the inheritance; effectively, we’ve mapped two unrelated tables to a more expressive class structure. If the base class was concrete, then an additional table would be needed to hold instances of that class. I have to emphasize that there is no relationship between the database tables, except for the fact that they share some similar columns. TPC Implementation in Code First Just like the TPT implementation, we need to specify a separate table for each of the subclasses. We also need to tell Code First that we want all of the inherited properties to be mapped as part of this table. In CTP5, there is a new helper method on EntityMappingConfiguration class called MapInheritedProperties that exactly does this for us. Here is the complete object model as well as the fluent API to create a TPC mapping: public abstract class BillingDetail {     public int BillingDetailId { get; set; }     public string Owner { get; set; }     public string Number { get; set; } }          public class BankAccount : BillingDetail {     public string BankName { get; set; }     public string Swift { get; set; } }          public class CreditCard : BillingDetail {     public int CardType { get; set; }     public string ExpiryMonth { get; set; }     public string ExpiryYear { get; set; } }      public class InheritanceMappingContext : DbContext {     public DbSet<BillingDetail> BillingDetails { get; set; }              protected override void OnModelCreating(ModelBuilder modelBuilder)     {         modelBuilder.Entity<BankAccount>().Map(m =>         {             m.MapInheritedProperties();             m.ToTable("BankAccounts");         });         modelBuilder.Entity<CreditCard>().Map(m =>         {             m.MapInheritedProperties();             m.ToTable("CreditCards");         });                 } } The Importance of EntityMappingConfiguration ClassAs a side note, it worth mentioning that EntityMappingConfiguration class turns out to be a key type for inheritance mapping in Code First. Here is an snapshot of this class: namespace System.Data.Entity.ModelConfiguration.Configuration.Mapping {     public class EntityMappingConfiguration<TEntityType> where TEntityType : class     {         public ValueConditionConfiguration Requires(string discriminator);         public void ToTable(string tableName);         public void MapInheritedProperties();     } } As you have seen so far, we used its Requires method to customize TPH. We also used its ToTable method to create a TPT and now we are using its MapInheritedProperties along with ToTable method to create our TPC mapping. TPC Configuration is Not Done Yet!We are not quite done with our TPC configuration and there is more into this story even though the fluent API we saw perfectly created a TPC mapping for us in the database. To see why, let's start working with our object model. For example, the following code creates two new objects of BankAccount and CreditCard types and tries to add them to the database: using (var context = new InheritanceMappingContext()) {     BankAccount bankAccount = new BankAccount();     CreditCard creditCard = new CreditCard() { CardType = 1 };                      context.BillingDetails.Add(bankAccount);     context.BillingDetails.Add(creditCard);     context.SaveChanges(); } Running this code throws an InvalidOperationException with this message: The changes to the database were committed successfully, but an error occurred while updating the object context. The ObjectContext might be in an inconsistent state. Inner exception message: AcceptChanges cannot continue because the object's key values conflict with another object in the ObjectStateManager. Make sure that the key values are unique before calling AcceptChanges. The reason we got this exception is because DbContext.SaveChanges() internally invokes SaveChanges method of its internal ObjectContext. ObjectContext's SaveChanges method on its turn by default calls AcceptAllChanges after it has performed the database modifications. AcceptAllChanges method merely iterates over all entries in ObjectStateManager and invokes AcceptChanges on each of them. Since the entities are in Added state, AcceptChanges method replaces their temporary EntityKey with a regular EntityKey based on the primary key values (i.e. BillingDetailId) that come back from the database and that's where the problem occurs since both the entities have been assigned the same value for their primary key by the database (i.e. on both BillingDetailId = 1) and the problem is that ObjectStateManager cannot track objects of the same type (i.e. BillingDetail) with the same EntityKey value hence it throws. If you take a closer look at the TPC's SQL schema above, you'll see why the database generated the same values for the primary keys: the BillingDetailId column in both BankAccounts and CreditCards table has been marked as identity. How to Solve The Identity Problem in TPC As you saw, using SQL Server’s int identity columns doesn't work very well together with TPC since there will be duplicate entity keys when inserting in subclasses tables with all having the same identity seed. Therefore, to solve this, either a spread seed (where each table has its own initial seed value) will be needed, or a mechanism other than SQL Server’s int identity should be used. Some other RDBMSes have other mechanisms allowing a sequence (identity) to be shared by multiple tables, and something similar can be achieved with GUID keys in SQL Server. While using GUID keys, or int identity keys with different starting seeds will solve the problem but yet another solution would be to completely switch off identity on the primary key property. As a result, we need to take the responsibility of providing unique keys when inserting records to the database. We will go with this solution since it works regardless of which database engine is used. Switching Off Identity in Code First We can switch off identity simply by placing DatabaseGenerated attribute on the primary key property and pass DatabaseGenerationOption.None to its constructor. DatabaseGenerated attribute is a new data annotation which has been added to System.ComponentModel.DataAnnotations namespace in CTP5: public abstract class BillingDetail {     [DatabaseGenerated(DatabaseGenerationOption.None)]     public int BillingDetailId { get; set; }     public string Owner { get; set; }     public string Number { get; set; } } As always, we can achieve the same result by using fluent API, if you prefer that: modelBuilder.Entity<BillingDetail>()             .Property(p => p.BillingDetailId)             .HasDatabaseGenerationOption(DatabaseGenerationOption.None); Working With The Object Model Our TPC mapping is ready and we can try adding new records to the database. But, like I said, now we need to take care of providing unique keys when creating new objects: using (var context = new InheritanceMappingContext()) {     BankAccount bankAccount = new BankAccount()      {          BillingDetailId = 1                          };     CreditCard creditCard = new CreditCard()      {          BillingDetailId = 2,         CardType = 1     };                      context.BillingDetails.Add(bankAccount);     context.BillingDetails.Add(creditCard);     context.SaveChanges(); } Polymorphic Associations with TPC is Problematic The main problem with this approach is that it doesn’t support Polymorphic Associations very well. After all, in the database, associations are represented as foreign key relationships and in TPC, the subclasses are all mapped to different tables so a polymorphic association to their base class (abstract BillingDetail in our example) cannot be represented as a simple foreign key relationship. For example, consider the the domain model we introduced here where User has a polymorphic association with BillingDetail. This would be problematic in our TPC Schema, because if User has a many-to-one relationship with BillingDetail, the Users table would need a single foreign key column, which would have to refer both concrete subclass tables. This isn’t possible with regular foreign key constraints. Schema Evolution with TPC is Complex A further conceptual problem with this mapping strategy is that several different columns, of different tables, share exactly the same semantics. This makes schema evolution more complex. For example, a change to a base class property results in changes to multiple columns. It also makes it much more difficult to implement database integrity constraints that apply to all subclasses. Generated SQLLet's examine SQL output for polymorphic queries in TPC mapping. For example, consider this polymorphic query for all BillingDetails and the resulting SQL statements that being executed in the database: var query = from b in context.BillingDetails select b; Just like the SQL query generated by TPT mapping, the CASE statements that you see in the beginning of the query is merely to ensure columns that are irrelevant for a particular row have NULL values in the returning flattened table. (e.g. BankName for a row that represents a CreditCard type). TPC's SQL Queries are Union Based As you can see in the above screenshot, the first SELECT uses a FROM-clause subquery (which is selected with a red rectangle) to retrieve all instances of BillingDetails from all concrete class tables. The tables are combined with a UNION operator, and a literal (in this case, 0 and 1) is inserted into the intermediate result; (look at the lines highlighted in yellow.) EF reads this to instantiate the correct class given the data from a particular row. A union requires that the queries that are combined, project over the same columns; hence, EF has to pad and fill up nonexistent columns with NULL. This query will really perform well since here we can let the database optimizer find the best execution plan to combine rows from several tables. There is also no Joins involved so it has a better performance than the SQL queries generated by TPT where a Join is required between the base and subclasses tables. Choosing Strategy GuidelinesBefore we get into this discussion, I want to emphasize that there is no one single "best strategy fits all scenarios" exists. As you saw, each of the approaches have their own advantages and drawbacks. Here are some rules of thumb to identify the best strategy in a particular scenario: If you don’t require polymorphic associations or queries, lean toward TPC—in other words, if you never or rarely query for BillingDetails and you have no class that has an association to BillingDetail base class. I recommend TPC (only) for the top level of your class hierarchy, where polymorphism isn’t usually required, and when modification of the base class in the future is unlikely. If you do require polymorphic associations or queries, and subclasses declare relatively few properties (particularly if the main difference between subclasses is in their behavior), lean toward TPH. Your goal is to minimize the number of nullable columns and to convince yourself (and your DBA) that a denormalized schema won’t create problems in the long run. If you do require polymorphic associations or queries, and subclasses declare many properties (subclasses differ mainly by the data they hold), lean toward TPT. Or, depending on the width and depth of your inheritance hierarchy and the possible cost of joins versus unions, use TPC. By default, choose TPH only for simple problems. For more complex cases (or when you’re overruled by a data modeler insisting on the importance of nullability constraints and normalization), you should consider the TPT strategy. But at that point, ask yourself whether it may not be better to remodel inheritance as delegation in the object model (delegation is a way of making composition as powerful for reuse as inheritance). Complex inheritance is often best avoided for all sorts of reasons unrelated to persistence or ORM. EF acts as a buffer between the domain and relational models, but that doesn’t mean you can ignore persistence concerns when designing your classes. SummaryIn this series, we focused on one of the main structural aspect of the object/relational paradigm mismatch which is inheritance and discussed how EF solve this problem as an ORM solution. We learned about the three well-known inheritance mapping strategies and their implementations in EF Code First. Hopefully it gives you a better insight about the mapping of inheritance hierarchies as well as choosing the best strategy for your particular scenario. Happy New Year and Happy Code-Firsting! References ADO.NET team blog Java Persistence with Hibernate book a { color: #5A99FF; } a:visited { color: #5A99FF; } .title { padding-bottom: 5px; font-family: Segoe UI; font-size: 11pt; font-weight: bold; padding-top: 15px; } .code, .typeName { font-family: consolas; } .typeName { color: #2b91af; } .padTop5 { padding-top: 5px; } .padTop10 { padding-top: 10px; } .exception { background-color: #f0f0f0; font-style: italic; padding-bottom: 5px; padding-left: 5px; padding-top: 5px; padding-right: 5px; }

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  • Adding Client Validation To DataAnnotations DataType Attribute

    - by srkirkland
    The System.ComponentModel.DataAnnotations namespace contains a validation attribute called DataTypeAttribute, which takes an enum specifying what data type the given property conforms to.  Here are a few quick examples: public class DataTypeEntity { [DataType(DataType.Date)] public DateTime DateTime { get; set; }   [DataType(DataType.EmailAddress)] public string EmailAddress { get; set; } } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } This attribute comes in handy when using ASP.NET MVC, because the type you specify will determine what “template” MVC uses.  Thus, for the DateTime property if you create a partial in Views/[loc]/EditorTemplates/Date.ascx (or cshtml for razor), that view will be used to render the property when using any of the Html.EditorFor() methods. One thing that the DataType() validation attribute does not do is any actual validation.  To see this, let’s take a look at the EmailAddress property above.  It turns out that regardless of the value you provide, the entity will be considered valid: //valid new DataTypeEntity {EmailAddress = "Foo"}; .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } Hmmm.  Since DataType() doesn’t validate, that leaves us with two options: (1) Create our own attributes for each datatype to validate, like [Date], or (2) add validation into the DataType attribute directly.  In this post, I will show you how to hookup client-side validation to the existing DataType() attribute for a desired type.  From there adding server-side validation would be a breeze and even writing a custom validation attribute would be simple (more on that in future posts). Validation All The Way Down Our goal will be to leave our DataTypeEntity class (from above) untouched, requiring no reference to System.Web.Mvc.  Then we will make an ASP.NET MVC project that allows us to create a new DataTypeEntity and hookup automatic client-side date validation using the suggested “out-of-the-box” jquery.validate bits that are included with ASP.NET MVC 3.  For simplicity I’m going to focus on the only DateTime field, but the concept is generally the same for any other DataType. Building a DataTypeAttribute Adapter To start we will need to build a new validation adapter that we can register using ASP.NET MVC’s DataAnnotationsModelValidatorProvider.RegisterAdapter() method.  This method takes two Type parameters; The first is the attribute we are looking to validate with and the second is an adapter that should subclass System.Web.Mvc.ModelValidator. Since we are extending DataAnnotations we can use the subclass of ModelValidator called DataAnnotationsModelValidator<>.  This takes a generic argument of type DataAnnotations.ValidationAttribute, which lucky for us means the DataTypeAttribute will fit in nicely. So starting from there and implementing the required constructor, we get: public class DataTypeAttributeAdapter : DataAnnotationsModelValidator<DataTypeAttribute> { public DataTypeAttributeAdapter(ModelMetadata metadata, ControllerContext context, DataTypeAttribute attribute) : base(metadata, context, attribute) { } } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } Now you have a full-fledged validation adapter, although it doesn’t do anything yet.  There are two methods you can override to add functionality, IEnumerable<ModelValidationResult> Validate(object container) and IEnumerable<ModelClientValidationRule> GetClientValidationRules().  Adding logic to the server-side Validate() method is pretty straightforward, and for this post I’m going to focus on GetClientValidationRules(). Adding a Client Validation Rule Adding client validation is now incredibly easy because jquery.validate is very powerful and already comes with a ton of validators (including date and regular expressions for our email example).  Teamed with the new unobtrusive validation javascript support we can make short work of our ModelClientValidationDateRule: public class ModelClientValidationDateRule : ModelClientValidationRule { public ModelClientValidationDateRule(string errorMessage) { ErrorMessage = errorMessage; ValidationType = "date"; } } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } If your validation has additional parameters you can the ValidationParameters IDictionary<string,object> to include them.  There is a little bit of conventions magic going on here, but the distilled version is that we are defining a “date” validation type, which will be included as html5 data-* attributes (specifically data-val-date).  Then jquery.validate.unobtrusive takes this attribute and basically passes it along to jquery.validate, which knows how to handle date validation. Finishing our DataTypeAttribute Adapter Now that we have a model client validation rule, we can return it in the GetClientValidationRules() method of our DataTypeAttributeAdapter created above.  Basically I want to say if DataType.Date was provided, then return the date rule with a given error message (using ValidationAttribute.FormatErrorMessage()).  The entire adapter is below: public class DataTypeAttributeAdapter : DataAnnotationsModelValidator<DataTypeAttribute> { public DataTypeAttributeAdapter(ModelMetadata metadata, ControllerContext context, DataTypeAttribute attribute) : base(metadata, context, attribute) { }   public override System.Collections.Generic.IEnumerable<ModelClientValidationRule> GetClientValidationRules() { if (Attribute.DataType == DataType.Date) { return new[] { new ModelClientValidationDateRule(Attribute.FormatErrorMessage(Metadata.GetDisplayName())) }; }   return base.GetClientValidationRules(); } } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } Putting it all together Now that we have an adapter for the DataTypeAttribute, we just need to tell ASP.NET MVC to use it.  The easiest way to do this is to use the built in DataAnnotationsModelValidatorProvider by calling RegisterAdapter() in your global.asax startup method. DataAnnotationsModelValidatorProvider.RegisterAdapter(typeof(DataTypeAttribute), typeof(DataTypeAttributeAdapter)); .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } Show and Tell Let’s see this in action using a clean ASP.NET MVC 3 project.  First make sure to reference the jquery, jquery.vaidate and jquery.validate.unobtrusive scripts that you will need for client validation. Next, let’s make a model class (note we are using the same built-in DataType() attribute that comes with System.ComponentModel.DataAnnotations). public class DataTypeEntity { [DataType(DataType.Date, ErrorMessage = "Please enter a valid date (ex: 2/14/2011)")] public DateTime DateTime { get; set; } } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } Then we make a create page with a strongly-typed DataTypeEntity model, the form section is shown below (notice we are just using EditorForModel): @using (Html.BeginForm()) { @Html.ValidationSummary(true) <fieldset> <legend>Fields</legend>   @Html.EditorForModel()   <p> <input type="submit" value="Create" /> </p> </fieldset> } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } The final step is to register the adapter in our global.asax file: DataAnnotationsModelValidatorProvider.RegisterAdapter(typeof(DataTypeAttribute), typeof(DataTypeAttributeAdapter)); Now we are ready to run the page: Looking at the datetime field’s html, we see that our adapter added some data-* validation attributes: <input type="text" value="1/1/0001" name="DateTime" id="DateTime" data-val-required="The DateTime field is required." data-val-date="Please enter a valid date (ex: 2/14/2011)" data-val="true" class="text-box single-line valid"> .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } Here data-val-required was added automatically because DateTime is non-nullable, and data-val-date was added by our validation adapter.  Now if we try to add an invalid date: Our custom error message is displayed via client-side validation as soon as we tab out of the box.  If we didn’t include a custom validation message, the default DataTypeAttribute “The field {0} is invalid” would have been shown (of course we can change the default as well).  Note we did not specify server-side validation, but in this case we don’t have to because an invalid date will cause a server-side error during model binding. Conclusion I really like how easy it is to register new data annotations model validators, whether they are your own or, as in this post, supplements to existing validation attributes.  I’m still debating about whether adding the validation directly in the DataType attribute is the correct place to put it versus creating a dedicated “Date” validation attribute, but it’s nice to know either option is available and, as we’ve seen, simple to implement. I’m also working through the nascent stages of an open source project that will create validation attribute extensions to the existing data annotations providers using similar techniques as seen above (examples: Email, Url, EqualTo, Min, Max, CreditCard, etc).  Keep an eye on this blog and subscribe to my twitter feed (@srkirkland) if you are interested for announcements.

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  • Erasing and modifying elements in Boost MultiIndex Container

    - by Sarah
    I'm trying to use a Boost MultiIndex container in my simulation. My knowledge of C++ syntax is very weak, and I'm concerned I'm not properly removing an element from the container or deleting it from memory. I also need to modify elements, and I was hoping to confirm the syntax and basic philosophy here too. // main.cpp ... #include <boost/multi_index_container.hpp> #include <boost/multi_index/hashed_index.hpp> #include <boost/multi_index/member.hpp> #include <boost/multi_index/ordered_index.hpp> #include <boost/multi_index/mem_fun.hpp> #include <boost/tokenizer.hpp> #include <boost/shared_ptr.hpp> ... #include "Host.h" // class Host, all members private, using get fxns to access using boost::multi_index_container; using namespace boost::multi_index; typedef multi_index_container< boost::shared_ptr< Host >, indexed_by< hashed_unique< const_mem_fun<Host,int,&Host::getID> > // ordered_non_unique< BOOST_MULTI_INDEX_MEM_FUN(Host,int,&Host::getAge) > > // end indexed_by > HostContainer; typedef HostContainer::nth_index<0>::type HostsByID; int main() { ... HostContainer allHosts; Host * newHostPtr; newHostPtr = new Host( t, DOB, idCtr, 0, currentEvents ); allHosts.insert( boost::shared_ptr<Host>(newHostPtr) ); // allHosts gets filled up int randomHostID = 4; int newAge = 50; modifyHost( randomHostID, allHosts, newAge ); killHost( randomHostID, allHosts ); } void killHost( int id, HostContainer & hmap ){ HostsByID::iterator it = hmap.find( id ); cout << "Found host id " << (*it)->getID() << "Attempting to kill. hmap.size() before is " << hmap.size() << " and "; hmap.erase( it ); // Is this really erasing (freeing from mem) the underlying Host object? cout << hmap.size() << " after." << endl; } void modifyHost( int id, HostContainer & hmap, int newAge ){ HostsByID::iterator it = hmap.find( id ); (*it) -> setAge( newAge ); // Not actually the "modify" function for MultiIndex... } My questions are In the MultiIndex container allHosts of shared_ptrs to Host objects, is calling allHosts.erase( it ) on an iterator to the object's shared_ptr enough to delete the object permanently and free it from memory? It appears to be removing the shared_ptr from the container. The allhosts container currently has one functioning index that relies on the host's ID. If I introduce an ordered second index that calls on a member function (Host::getAge()), where the age changes over the course of the simulation, is the index always going to be updated when I refer to it? What is the difference between using the MultiIndex's modify to modify the age of the underlying object versus the approach I show above? I'm vaguely confused about what is assumed/required to be constant in MultiIndex. Thanks in advance. Update Here's my attempt to get the modify syntax working, based on what I see in a related Boost example. struct update_age { update_age():(){} // have no idea what this really does... elicits error void operator() (boost::shared_ptr<Host> ptr) { ptr->incrementAge(); // incrementAge() is a member function of class Host } }; and then in modifyHost, I'd have hmap.modify(it,update_age). Even if by some miracle this turns out to be right, I'd love some kind of explanation of what's going on.

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  • e-interview: SunSpace to WebCenter migration

    - by me
    I had the pleasure to do an e-interview with Ana Neves around the SunSpace to WebCenter migration project.  Below is the english version of the interview.  Enjoy   Peter, you joined Oracle in 2009 through the acquisition of Sun. Becoming a part of Oracle meant many changes. The internal collaboration platform was one of them, as per a post you wrote back in 2011. Sun had SunSpace. How would you describe SunSpace? SunSpace was the internal Community and Social Collaboration platform for the Sun's Global Sales and Services Organization. SunSpace served around 600 communities with a main focus around technology, products and services. SunSpace was a big success. Within 3 months of its launch SunSpace had over 20,000 users and it won the Atlassian "Not just another wiki" Award for the best use of Confluence (https://blogs.oracle.com/peterreiser/entry/goodbye_sunspace_hello_webcenter). What made SunSpace so special? 1. People centric versus  Web centric The main concept of SunSpace put the person in the middle of everything. All relevant information, resources  etc. where dynamically pushed to a person's  myProfile ( Facebook like interface) based on the person's interest and  needs.  2. Ease to use  SunSpace was really easy to use. We spent a lot of time on social interaction design to optimize the user experience.  Also we integrated some sophisticated technology to hide complexity from the user. As example - when a user added a document to SunSpace - we analyzed the content of the document and suggested related metadata and tags to the user based on a sophisticated algorithm which was integrated with the corporate taxonomy. Based on this metadata the document was automatically shared with the relevant communities.  3. Easy to find One of the main use cases for SunSpace was that  a user could quickly find the content and information they needed for their job.  The search implementation was based on:  optimized search engine algorithm using social value based ranking enhancements community facilitated search optimization  faceted search which recommended highly relevant  content like products, communities and experts 4. Social Adoption  - How to build vibrant communities You can deploy the coolest social technology but what if the users are not using it?   To drive user adoption we implemented two  complementary models: 4.1 Community Methodology  We developed a set of best practices on how to create, run and sustain communities including: community structure and types (e.g. Community of Practice, Community of Interest etc.) & tips and tricks on how to build a "vibrant " communities, Community Health check etc.  These best practices where constantly tuned and updated by the community of community drivers. 4.2. Social Value System To drive user adoption there is ONE key  question you  have to answer for each individual user: What's In It For Me (WIIFM) We developed a Social Value System called Community Equity which measures the social value flow between People, Content and Metadata. Based on this technology we added "Gamfication" techniques (although at that time this term did not exist ) to SunSpace to honor people for the active contribution and participation.  As example: All  social credentials a user earned trough active community participation where dynamically displayed on her/his myProfile. How would you describe WebCenter? Oracle WebCenter (@oraclewebcenter) is the Oracle's  user engagement platform for social business. It helps people work together more efficiently through contextual collaboration tools that optimize connections between people, information, and applications and ensures users have access to the right information in the context of the business process in which they are engaged. Oracle WebCenter can help your organization deliver contextual and targeted Web experiences to users and enable employees to access information and applications through intuitive portals, composite applications, and mash-ups. How does it compare to SunSpace in terms of functionality? Before I answer this question, I would like to point out some limitation we started to see with the current SunSpace implementation. Due to the massive growth of the user population (>20,000 users), we experienced  performance and scalability challenges with the current technology. Also at the time - Sun Internal Communications and SunIT planned to replace the entire Sun Intranet with SunSpace. We  kicked-off a project to evaluate the enterprise level technology which eventually would replace the good old static Intranet.  And then Oracle acquired Sun. We already had defined the functional requirements for the Intranet replacement with a Social Enterprise Stack and we just needed to evaluate the functional requirements against WebCenter   Below are the summary of this evaluation  MyProfile SunSpace WebCenter How WebCenter Works Home MyProfile: to access, click on your name at the top of any WebCenter page Your name, title, and reporting line are displayed.  Sub-tabs show your activity stream (Activities); people in your network (Connections); files you have uploaded (Documents); your contact information (Organization); and any personal information you wish to share (About).   Files MyFiles Allows you to upload, download and store documents or wiki pages within folders and subfolders.  The WebDav interface allows you to download / upload files / folders with a simple drag and drop to / from your local machine.  Tagging is supported and recommended. Network HomeMyConnections Home: displays the activity stream of individuals in your network.MyConnections: shows individuals in your network.  Click on a person's name to see their contact info and link to their profile. Status Updates MyProfle > Activties Add and displays  your recent activties and status updates. Watches Preferences > Subscriptions > Current Subscriptions Receive email notifications when  pages / spaces you watch are modified. Drafts N/A WebCenter does not support Drafts Settings Preferences: to access, click on 'Preferences' at the top of any WebCenter page Set your general preferences, as well as your WebCenter messaging, search and mail settings. MyCommunities MySpaces: to access, click on 'Spaces' at the top of any WebCenter page Displays MySpaces (communities you are a member of); and Recent Spaces (communities you have recently visited). Community SunSpace Webcenter How Webcenter Works Home Home Displays a community introduction and activity stream.  Members can add messages, links or documents via the Community Message Board. No Top Contributors widget. People Members Lists members of the community. The Mail All Members feature allows moderators and participants to send a message to all members of the community. Membership Management can be found under > Manage > Members News News Members can post and access latest community news and they can subscribe to news using an RSS reader Documents Documents Allows community members to upload, download and store documents or wiki pages within folders and subfolders.  The WebDav interface allows participants to download / upload files / folders with a simple drag and drop to / from your local machine.  Tagging is supported and recommended. Wiki Wiki Allows community members to create and update web pages with a WYSIWYG editor.  Note: WebCenter does not support macros or portlet embedding. Forum Forum Post community forum topics. Contribute to community forum conversations.  N/A Calendar Update and/or view the Community Calendar. N/A Analytics Displays detailed analytics data (views,downloads, unique users etc.) for Pages, Wiki, Documents, and Forum in a given community space. What is the adoption of WebCenter at Oracle? The entire Intranet serving around 100,000 users  is running on WebCenter Content.  For professional communities we use WebCenter Portal and Spaces. Currently we have around 6,000 community spaces with  around 40,000 members.  Does Oracle have any metrics to assess usage and impact of WebCenter? Can you give us some examples? Sure -  we have a lot of metrics   For the Intranet we use traditional metrics like pageviews, monthly unique visitors and unique visits.  For Communities we use the WebCenter Portal/Spaces analytics service which gives as a wealth of data. The key metrics we track are: Space traffic (PageViews, Unique Users) Wiki,Documents (views, downloads etc.) Forum (users, views, posts etc.) Registered members over time  Depending on the community we can filter/segment the metrics by User Properties e.g. Country, Organization, Job Role etc. What are you doing to improve usage and impact? 1. We  integrating the WebCenter social services/fabric into all  main business applications. As example The Fusion CRM deployment is seamless integrated with Oracle Social Network (OSN) and all conversation around an opportunity or customer engagement is  done in OSN (see youtube video). 2. We drive Social Best Practice trough a program called "Social Networking & Business Collaboration (SNBC) program" You worked both with WebCenter and SunSpace. Knowing what you know today, if you had the chance to choose between the two, which one would you choose? Why? That's a tricky question   In the early days of  the Social Enterprise implementation (we started SunSpace in 2006), we needed an agile and easy to deploy technology to keep up with the users requirements. Sometimes we pushed two releases per day  and we were in a permanent perpetual beta mode - SunSpace was perfect for that.  After the social implementation matured over time - community generated content became business critical and we saw a change in the  requirements from agile to stability, scalability and reliability  of the infrastructure.  WebCenter is the right choice for such an enterprise-level deployment.  You are a WebCenter Evangelist at Oracle. What do you do as part of that role? Our  role is to help position Oracle as one of the key thought leaders and solutions provider for Social Business. In addition we drive social innovation trough our Oracle Appslab  team. Is that a full time role? Yes  How many other Evangelists are there in Oracle? We are currently 5 people in the WebCenter evangelist team (@webcentervoices): Christian Finn (@cfinn) leads the team - Christian came from the Microsoft Sharepoint product management team and is a recognized expert in Social Business and Enterprise Collaboration. Noël Jaffré  (@noeljaffre) is our Web Experience Management (WEM) guru and came to Oracle via FatWire acquisition (now WebCenter Sites). Jake Kuramoto (@theapplab) is part of the Oracle AppsLab innovation  team - Jake is well known as  the driving force behind  http://theappslab.com  a blog around social and innovation.  Noel Portugal (@noelportugal) is a developer in the Oracle AppsLab innovation team - he is the inventor of OraTweet - Oracle's internal tweeting platform  Peter Reiser (@peterreiser) is  a Social Business guru and the inventor of SunSpace and Community Equity.  What area of the business do you and the rest of the Evangelists sit in? What area of the organisation is responsible for WebCenter? We are part of the WebCenter product management  organization.  Is WebCenter part of the Knowledge Management strategy? Oracle WebCenter is the Oracle's user engagement platform for social business. It brings together the most complete portfolio of portal, web experience management, content, social and collaboration technologies into a single product suite and is the product foundation of the Oracle Knowledge Management strategy.  I am aware Oracle also uses Beehive internally. How would you describe Beehive? Oracle Beehive provides an integrated set of communication and collaboration services built on a single scalable, secure, enterprise-class platform Beehive is  internally used for enterprise wide mail, calendar and real collaboration (Web conferencing) services.  Are Beehive and WebCenter connected? Historically Beehive and WebCenter Portal & Content had some overlap in functionally. (Hey - if  a company has an acquisition strategy to strengthen its product offering and accelerate  innovation, it's pretty normal that functional overlap exists  :- )) A key objective of the WebCenter strategy is  to combine all social and collaboration offerings under the WebCenter product family. That means that certain Beehive components  will be integrated into the overall WebCenter product offering.  Are there any other internal collaboration tools at Oracle? Which ones There here are two other main social tools which are widely used at Oracle  Oracle Connect was the first social tool the Oracle AppsLab team created in 2007 - see (Jake's blog post for details). It is still extensively used. ... and as a former Sun guy I like this quote from the blog post:  "Traffic to Connect peaked right after the Sun merger in 2010, when it served several hundred thousand pageviews each month; since then, traffic has subsided, but still averages tens of thousands of pageviews to several thousand users each month." Oratweet - Oracle internal microblogging platform has been used since June 2008 and it is still growing.  It's entirely written in Oracle Application Express (APEX) which is a rapid web application development tool for the Oracle database. Wanna try it out? Here you can download the code.  What is Oracle's strategy regarding (all these) collaboration tools? Pretty straight forward. The strategy is to seamless  integrate the WebCenter social & collaboration services into all Business Applications to help customers to socialize their enterprise. 

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  • EF4 generates invalid script

    - by Jaxidian
    When I right-click in a .EDMX file and click Generate Database From Model, the resulting script is obviously wrong because of the table names. What it generates is the following script. Note the table names in the DROP TABLE part versus the CREATE TABLE part. Why is this inconsistent? This is obviously not a reusable script. What I created was an Entity named "Address" and an Entity named "Company", etc (all singular). The EntitySet names are pluralized. The "Pluralize New Objects" boolean does not change this either. So what's the deal? For what it's worth, I originally generated the EDMX by pointing it to a database that had tables with non-pluralized names and now that I've made some changes, I want to go back the other way. I'd like to have the option to go back and forth as neither the db-first nor the model-first model is ideal in all scenarios, and I have the control to ensure that there will be no merging issues from multiple people going both ways at the same time. -- -------------------------------------------------- -- Dropping existing FOREIGN KEY constraints -- NOTE: if the constraint does not exist, an ignorable error will be reported. -- -------------------------------------------------- ALTER TABLE [Address] DROP CONSTRAINT [FK_Address_StateID-State_ID]; GO ALTER TABLE [Company] DROP CONSTRAINT [FK_Company_AddressID-Address_ID]; GO ALTER TABLE [Employee] DROP CONSTRAINT [FK_Employee_BossEmployeeID-Employee_ID]; GO ALTER TABLE [Employee] DROP CONSTRAINT [FK_Employee_CompanyID-Company_ID]; GO ALTER TABLE [Employee] DROP CONSTRAINT [FK_Employee_PersonID-Person_ID]; GO ALTER TABLE [Person] DROP CONSTRAINT [FK_Person_AddressID-Address_ID]; GO -- -------------------------------------------------- -- Dropping existing tables -- NOTE: if the table does not exist, an ignorable error will be reported. -- -------------------------------------------------- DROP TABLE [Address]; GO DROP TABLE [Company]; GO DROP TABLE [Employee]; GO DROP TABLE [Person]; GO DROP TABLE [State]; GO -- -------------------------------------------------- -- Creating all tables -- -------------------------------------------------- -- Creating table 'Addresses' CREATE TABLE [Addresses] ( [ID] int IDENTITY(1,1) NOT NULL, [StreetAddress] nvarchar(100) NOT NULL, [City] nvarchar(100) NOT NULL, [StateID] int NOT NULL, [Zip] nvarchar(10) NOT NULL ); GO -- Creating table 'Companies' CREATE TABLE [Companies] ( [ID] int IDENTITY(1,1) NOT NULL, [Name] nvarchar(100) NOT NULL, [AddressID] int NOT NULL ); GO -- Creating table 'People' CREATE TABLE [People] ( [ID] int IDENTITY(1,1) NOT NULL, [FirstName] nvarchar(100) NOT NULL, [LastName] nvarchar(100) NOT NULL, [AddressID] int NOT NULL ); GO -- Creating table 'States' CREATE TABLE [States] ( [ID] int IDENTITY(1,1) NOT NULL, [Name] nvarchar(100) NOT NULL, [Abbreviation] nvarchar(2) NOT NULL ); GO -- Creating table 'Employees' CREATE TABLE [Employees] ( [ID] int IDENTITY(1,1) NOT NULL, [PersonID] int NOT NULL, [CompanyID] int NOT NULL, [Position] nvarchar(100) NOT NULL, [BossEmployeeID] int NULL ); GO -- -------------------------------------------------- -- Creating all PRIMARY KEY constraints -- -------------------------------------------------- -- Creating primary key on [ID] in table 'Addresses' ALTER TABLE [Addresses] ADD CONSTRAINT [PK_Addresses] PRIMARY KEY ([ID] ); GO -- Creating primary key on [ID] in table 'Companies' ALTER TABLE [Companies] ADD CONSTRAINT [PK_Companies] PRIMARY KEY ([ID] ); GO -- Creating primary key on [ID] in table 'People' ALTER TABLE [People] ADD CONSTRAINT [PK_People] PRIMARY KEY ([ID] ); GO -- Creating primary key on [ID] in table 'States' ALTER TABLE [States] ADD CONSTRAINT [PK_States] PRIMARY KEY ([ID] ); GO -- Creating primary key on [ID] in table 'Employees' ALTER TABLE [Employees] ADD CONSTRAINT [PK_Employees] PRIMARY KEY ([ID] ); GO -- -------------------------------------------------- -- Creating all FOREIGN KEY constraints -- -------------------------------------------------- -- Creating foreign key on [StateID] in table 'Addresses' ALTER TABLE [Addresses] ADD CONSTRAINT [FK_Address_StateID_State_ID] FOREIGN KEY ([StateID]) REFERENCES [States] ([ID]) ON DELETE NO ACTION ON UPDATE NO ACTION; -- Creating non-clustered index for FOREIGN KEY 'FK_Address_StateID_State_ID' CREATE INDEX [IX_FK_Address_StateID_State_ID] ON [Addresses] ([StateID]); GO -- Creating foreign key on [AddressID] in table 'Companies' ALTER TABLE [Companies] ADD CONSTRAINT [FK_Company_AddressID_Address_ID] FOREIGN KEY ([AddressID]) REFERENCES [Addresses] ([ID]) ON DELETE NO ACTION ON UPDATE NO ACTION; -- Creating non-clustered index for FOREIGN KEY 'FK_Company_AddressID_Address_ID' CREATE INDEX [IX_FK_Company_AddressID_Address_ID] ON [Companies] ([AddressID]); GO -- Creating foreign key on [AddressID] in table 'People' ALTER TABLE [People] ADD CONSTRAINT [FK_Person_AddressID_Address_ID] FOREIGN KEY ([AddressID]) REFERENCES [Addresses] ([ID]) ON DELETE NO ACTION ON UPDATE NO ACTION; -- Creating non-clustered index for FOREIGN KEY 'FK_Person_AddressID_Address_ID' CREATE INDEX [IX_FK_Person_AddressID_Address_ID] ON [People] ([AddressID]); GO -- Creating foreign key on [CompanyID] in table 'Employees' ALTER TABLE [Employees] ADD CONSTRAINT [FK_Employee_CompanyID_Company_ID] FOREIGN KEY ([CompanyID]) REFERENCES [Companies] ([ID]) ON DELETE NO ACTION ON UPDATE NO ACTION; -- Creating non-clustered index for FOREIGN KEY 'FK_Employee_CompanyID_Company_ID' CREATE INDEX [IX_FK_Employee_CompanyID_Company_ID] ON [Employees] ([CompanyID]); GO -- Creating foreign key on [BossEmployeeID] in table 'Employees' ALTER TABLE [Employees] ADD CONSTRAINT [FK_Employee_BossEmployeeID_Employee_ID] FOREIGN KEY ([BossEmployeeID]) REFERENCES [Employees] ([ID]) ON DELETE NO ACTION ON UPDATE NO ACTION; -- Creating non-clustered index for FOREIGN KEY 'FK_Employee_BossEmployeeID_Employee_ID' CREATE INDEX [IX_FK_Employee_BossEmployeeID_Employee_ID] ON [Employees] ([BossEmployeeID]); GO -- Creating foreign key on [PersonID] in table 'Employees' ALTER TABLE [Employees] ADD CONSTRAINT [FK_Employee_PersonID_Person_ID] FOREIGN KEY ([PersonID]) REFERENCES [People] ([ID]) ON DELETE NO ACTION ON UPDATE NO ACTION; -- Creating non-clustered index for FOREIGN KEY 'FK_Employee_PersonID_Person_ID' CREATE INDEX [IX_FK_Employee_PersonID_Person_ID] ON [Employees] ([PersonID]); GO -- -------------------------------------------------- -- Script has ended -- --------------------------------------------------

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  • What statistics can be maintained for a set of numerical data without iterating?

    - by Dan Tao
    Update Just for future reference, I'm going to list all of the statistics that I'm aware of that can be maintained in a rolling collection, recalculated as an O(1) operation on every addition/removal (this is really how I should've worded the question from the beginning): Obvious Count Sum Mean Max* Min* Median** Less Obvious Variance Standard Deviation Skewness Kurtosis Mode*** Weighted Average Weighted Moving Average**** OK, so to put it more accurately: these are not "all" of the statistics I'm aware of. They're just the ones that I can remember off the top of my head right now. *Can be recalculated in O(1) for additions only, or for additions and removals if the collection is sorted (but in this case, insertion is not O(1)). Removals potentially incur an O(n) recalculation for non-sorted collections. **Recalculated in O(1) for a sorted, indexed collection only. ***Requires a fairly complex data structure to recalculate in O(1). ****This can certainly be achieved in O(1) for additions and removals when the weights are assigned in a linearly descending fashion. In other scenarios, I'm not sure. Original Question Say I maintain a collection of numerical data -- let's say, just a bunch of numbers. For this data, there are loads of calculated values that might be of interest; one example would be the sum. To get the sum of all this data, I could... Option 1: Iterate through the collection, adding all the values: double sum = 0.0; for (int i = 0; i < values.Count; i++) sum += values[i]; Option 2: Maintain the sum, eliminating the need to ever iterate over the collection just to find the sum: void Add(double value) { values.Add(value); sum += value; } void Remove(double value) { values.Remove(value); sum -= value; } EDIT: To put this question in more relatable terms, let's compare the two options above to a (sort of) real-world situation: Suppose I start listing numbers out loud and ask you to keep them in your head. I start by saying, "11, 16, 13, 12." If you've just been remembering the numbers themselves and nothing more, and then I say, "What's the sum?", you'd have to think to yourself, "OK, what's 11 + 16 + 13 + 12?" before responding, "52." If, on the other hand, you had been keeping track of the sum yourself while I was listing the numbers (i.e., when I said, "11" you thought "11", when I said "16", you thought, "27," and so on), you could answer "52" right away. Then if I say, "OK, now forget the number 16," if you've been keeping track of the sum inside your head you can simply take 16 away from 52 and know that the new sum is 36, rather than taking 16 off the list and them summing up 11 + 13 + 12. So my question is, what other calculations, other than the obvious ones like sum and average, are like this? SECOND EDIT: As an arbitrary example of a statistic that (I'm almost certain) does require iteration -- and therefore cannot be maintained as simply as a sum or average -- consider if I asked you, "how many numbers in this collection are divisible by the min?" Let's say the numbers are 5, 15, 19, 20, 21, 25, and 30. The min of this set is 5, which divides into 5, 15, 20, 25, and 30 (but not 19 or 21), so the answer is 5. Now if I remove 5 from the collection and ask the same question, the answer is now 2, since only 15 and 30 are divisible by the new min of 15; but, as far as I can tell, you cannot know this without going through the collection again. So I think this gets to the heart of my question: if we can divide kinds of statistics into these categories, those that are maintainable (my own term, maybe there's a more official one somewhere) versus those that require iteration to compute any time a collection is changed, what are all the maintainable ones? What I am asking about is not strictly the same as an online algorithm (though I sincerely thank those of you who introduced me to that concept). An online algorithm can begin its work without having even seen all of the input data; the maintainable statistics I am seeking will certainly have seen all the data, they just don't need to reiterate through it over and over again whenever it changes.

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  • Down Tools Week Cometh: Kissing Goodbye to CVs/Resumes and Cover Letters

    - by Bart Read
    I haven't blogged about what I'm doing in my (not so new) temporary role as Red Gate's technical recruiter, mostly because it's been routine, business as usual stuff, and because I've been trying to understand the role by doing it. I think now though the time has come to get a little more radical, so I'm going to tell you why I want to largely eliminate CVs/resumes and cover letters from the application process for some of our technical roles, and why I think that might be a good thing for candidates (and for us). I have a terrible confession to make, or at least it's a terrible confession for a recruiter: I don't really like CV sifting, or reading cover letters, and, unless I've misread the mood around here, neither does anybody else. It's dull, it's time-consuming, and it's somewhat soul destroying because, when all is said and done, you're being paid to be incredibly judgemental about people based on relatively little information. I feel like I've dirtied myself by saying that - I mean, after all, it's a core part of my job - but it sucks, it really does. (And, of course, the truth is I'm still a software engineer at heart, and I'm always looking for ways to do things better.) On the flip side, I've never met anyone who likes writing their CV. It takes hours and hours of faffing around and massaging it into shape, and the whole process is beset by a gnawing anxiety, frustration, and insecurity. All you really want is a chance to demonstrate your skills - not just talk about them - and how do you do that in a CV or cover letter? Often the best candidates will include samples of their work (a portfolio, screenshots, links to websites, product downloads, etc.), but sometimes this isn't possible, or may not be appropriate, or you just don't think you're allowed because of what your school/university careers service has told you (more commonly an issue with grads, obviously). And what are we actually trying to find out about people with all of this? I think the common criteria are actually pretty basic: Smart Gets things done (thanks for these two Joel) Not an a55hole* (sorry, have to get around Simple Talk's swear filter - and thanks to Professor Robert I. Sutton for this one) *Of course, everyone has off days, and I don't honestly think we're too worried about somebody being a bit grumpy every now and again. We can do a bit better than this in the context of the roles I'm talking about: we can be more specific about what "gets things done" means, at least in part. For software engineers and interns, the non-exhaustive meaning of "gets things done" is: Excellent coder For test engineers, the non-exhaustive meaning of "gets things done" is: Good at finding problems in software Competent coder Team player, etc., to me, are covered by "not an a55hole". I don't expect people to be the life and soul of the party, or a wild extrovert - that's not what team player means, and it's not what "not an a55hole" means. Some of our best technical staff are quiet, introverted types, but they're still pleasant to work with. My problem is that I don't think the initial sift really helps us find out whether people are smart and get things done with any great efficacy. It's better than nothing, for sure, but it's not as good as it could be. It's also contentious, and potentially unfair/inequitable - if you want to get an idea of what I mean by this, check out the background information section at the bottom. Before I go any further, let's look at the Red Gate recruitment process for technical staff* as it stands now: (LOTS of) People apply for jobs. All these applications go through a brutal process of manual sifting, which eliminates between 75 and 90% of them, depending upon the role, and the time of year**. Depending upon the role, those who pass the sift will be sent an assessment or telescreened. For the purposes of this blog post I'm only interested in those that are sent some sort of programming assessment, or bug hunt. This means software engineers, test engineers, and software interns, which are the roles for which I receive the most applications. The telescreen tends to be reserved for project or product managers. Those that pass the assessment are invited in for first interview. This interview is mostly about assessing their technical skills***, although we're obviously on the look out for cultural fit red flags as well. If the first interview goes well we'll invite candidates back for a second interview. This is where team/cultural fit is really scoped out. We also use this interview to dive more deeply into certain areas of their skillset, and explore any concerns that may have come out of the first interview (these obviously won't have been serious or obvious enough to cause a rejection at that point, but are things we do need to look into before we'd consider making an offer). We might subsequently invite them in for lunch before we make them an offer. This tends to happen when we're recruiting somebody for a specific team and we'd like them to meet all the people they'll be working with directly. It's not an interview per se, but can prove pivotal if they don't gel with the team. Anyone who's made it this far will receive an offer from us. *We have a slightly quirky definition of "technical staff" as it relates to the technical recruiter role here. It includes software engineers, test engineers, software interns, user experience specialists, technical authors, project managers, product managers, and development managers, but does not include product support or information systems roles. **For example, the quality of graduate applicants overall noticeably drops as the academic year wears on, which is not to say that by now there aren't still stars in there, just that they're fewer and further between. ***Some organisations prefer to assess for team fit first, but I think assessing technical skills is a more effective initial filter - if they're the nicest person in the world, but can't cut a line of code they're not going to work out. Now, as I suggested in the title, Red Gate's Down Tools Week is upon us once again - next week in fact - and I had proposed as a project that we refactor and automate the first stage of marking our programming assessments. Marking assessments, and in fact organising the marking of them, is a somewhat time-consuming process, and we receive many assessment solutions that just don't make the cut, for whatever reason. Whilst I don't think it's possible to fully automate marking, I do think it ought to be possible to run a suite of automated tests over each candidate's solution to see whether or not it behaves correctly and, if it does, move on to a manual stage where we examine the code for structure, decomposition, style, readability, maintainability, etc. Obviously it's possible to use tools to generate potentially helpful metrics for some of these indices as well. This would obviously reduce the marking workload, and would provide candidates with quicker feedback about whether they've been successful - though I do wonder if waiting a tactful interval before sending a (nicely written) rejection might be wise. I duly scrawled out a picture of my ideal process, which looked like this: The problem is, as soon as I'd roughed it out, I realised that fundamentally it wasn't an ideal process at all, which explained the gnawing feeling of cognitive dissonance I'd been wrestling with all week, whilst I'd been trying to find time to do this. Here's what I mean. Automated assessment marking, and the associated infrastructure around that, makes it much easier for us to deal with large numbers of assessments. This means we can be much more permissive about who we send assessments out to or, in other words, we can give more candidates the opportunity to really demonstrate their skills to us. And this leads to a question: why not give everyone the opportunity to demonstrate their skills, to show that they're smart and can get things done? (Two or three of us even discussed this in the down tools week hustings earlier this week.) And isn't this a lot simpler than the alternative we'd been considering? (FYI, this was automated CV/cover letter sifting by some form of textual analysis to ideally eliminate the worst 50% or so of applications based on an analysis of the 20,000 or so historical applications we've received since 2007 - definitely not the basic keyword analysis beloved of recruitment agencies, since this would eliminate hardly anyone who was awful, but definitely would eliminate stellar Oxbridge candidates - #fail - or some nightmarishly complex Google-like system where we profile all our currently employees, only to realise that we're never going to get representative results because we don't have a statistically significant sample size in any given role - also #fail.) No, I think the new way is better. We let people self-select. We make them the masters (or mistresses) of their own destiny. We give applicants the power - we put their fate in their hands - by giving them the chance to demonstrate their skills, which is what they really want anyway, instead of requiring that they spend hours and hours creating a CV and cover letter that I'm going to evaluate for suitability, and make a value judgement about, in approximately 1 minute (give or take). It doesn't matter what university you attended, it doesn't matter if you had a bad year when you took your A-levels - here's your chance to shine, so take it and run with it. (As a side benefit, we cut the number of applications we have to sift by something like two thirds.) WIN! OK, yeah, sounds good, but will it actually work? That's an excellent question. My gut feeling is yes, and I'll justify why below (and hopefully have gone some way towards doing that above as well), but what I'm proposing here is really that we run an experiment for a period of time - probably a couple of months or so - and measure the outcomes we see: How many people apply? (Wouldn't be surprised or alarmed to see this cut by a factor of ten.) How many of them submit a good assessment? (More/less than at present?) How much overhead is there for us in dealing with these assessments compared to now? What are the success and failure rates at each interview stage compared to now? How many people are we hiring at the end of it compared to now? I think it'll work because I hypothesize that, amongst other things: It self-selects for people who really want to work at Red Gate which, at the moment, is something I have to try and assess based on their CV and cover letter - but if you're not that bothered about working here, why would you complete the assessment? Candidates who would submit a shoddy application probably won't feel motivated to do the assessment. Candidates who would demonstrate good attention to detail in their CV/cover letter will demonstrate good attention to detail in the assessment. In general, only the better candidates will complete and submit the assessment. Marking assessments is much less work so we'll be able to deal with any increase that we see (hopefully we will see). There are obviously other questions as well: Is plagiarism going to be a problem? Is there any way we can detect/discourage potential plagiarism? How do we assess candidates' education and experience? What about their ability to communicate in writing? Do we still want them to submit a CV afterwards if they pass assessment? Do we want to offer them the opportunity to tell us a bit about why they'd like the job when they submit their assessment? How does this affect our relationship with recruitment agencies we might use to hire for these roles? So, what's the objective for next week's Down Tools Week? Pretty simple really - we want to implement this process for the Graduate Software Engineer and Software Engineer positions that you can find on our website. I will be joined by a crack team of our best developers (Kevin Boyle, and new Red-Gater, Sam Blackburn), and recruiting hostess with the mostest Laura McQuillen, and hopefully a couple of others as well - if I can successfully twist more arms before Monday.* Hopefully by next Friday our experiment will be up and running, and we may have changed the way Red Gate recruits software engineers for good! Stay tuned and we'll let you know how it goes! *I'm going to play dirty by offering them beer and chocolate during meetings. Some background information: how agonising over the initial CV/cover letter sift helped lead us to bin it off entirely The other day I was agonising about the new university/good degree grade versus poor A-level results issue, and decided to canvas for other opinions to see if there was something I could do that was fairer than my current approach, which is almost always to reject. This generated quite an involved discussion on our Yammer site: I'm sure you can glean a pretty good impression of my own educational prejudices from that discussion as well, although I'm very open to changing my opinion - hopefully you've already figured that out from reading the rest of this post. Hopefully you can also trace a logical path from agonising about sifting to, "Uh, hang on, why on earth are we doing this anyway?!?" Technorati Tags: recruitment,hr,developers,testers,red gate,cv,resume,cover letter,assessment,sea change

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  • Why are my Opteron cores running at only 75% capacity each? (25% CPU idle)

    - by Tim Cooper
    We've just taken delivery of a powerful 32-core AMD Opteron server with 128Gb. We have 2 x 6272 CPU's with 16 cores each. We are running a big long-running java task on 30 threads. We have the NUMA optimisations for Linux and java turned on. Our Java threads are mainly using objects that are private to that thread, sometimes reading memory that other threads will be reading, and very very occasionally writing or locking shared objects. We can't explain why the CPU cores are 25% idle. Below is a dump of "top": top - 23:06:38 up 1 day, 23 min, 3 users, load average: 10.84, 10.27, 9.62 Tasks: 676 total, 1 running, 675 sleeping, 0 stopped, 0 zombie Cpu(s): 64.5%us, 1.3%sy, 0.0%ni, 32.9%id, 1.3%wa, 0.0%hi, 0.0%si, 0.0%st Mem: 132138168k total, 131652664k used, 485504k free, 92340k buffers Swap: 5701624k total, 230252k used, 5471372k free, 13444344k cached ... top - 22:37:39 up 23:54, 3 users, load average: 7.83, 8.70, 9.27 Tasks: 678 total, 1 running, 677 sleeping, 0 stopped, 0 zombie Cpu0 : 75.8%us, 2.0%sy, 0.0%ni, 22.2%id, 0.0%wa, 0.0%hi, 0.0%si, 0.0%st Cpu1 : 77.2%us, 1.3%sy, 0.0%ni, 21.5%id, 0.0%wa, 0.0%hi, 0.0%si, 0.0%st Cpu2 : 77.3%us, 1.0%sy, 0.0%ni, 21.7%id, 0.0%wa, 0.0%hi, 0.0%si, 0.0%st Cpu3 : 77.8%us, 1.0%sy, 0.0%ni, 21.2%id, 0.0%wa, 0.0%hi, 0.0%si, 0.0%st Cpu4 : 76.9%us, 2.0%sy, 0.0%ni, 21.1%id, 0.0%wa, 0.0%hi, 0.0%si, 0.0%st Cpu5 : 76.3%us, 2.0%sy, 0.0%ni, 21.7%id, 0.0%wa, 0.0%hi, 0.0%si, 0.0%st Cpu6 : 12.6%us, 3.0%sy, 0.0%ni, 84.4%id, 0.0%wa, 0.0%hi, 0.0%si, 0.0%st Cpu7 : 8.6%us, 2.0%sy, 0.0%ni, 89.4%id, 0.0%wa, 0.0%hi, 0.0%si, 0.0%st Cpu8 : 77.0%us, 2.0%sy, 0.0%ni, 21.1%id, 0.0%wa, 0.0%hi, 0.0%si, 0.0%st Cpu9 : 77.0%us, 2.0%sy, 0.0%ni, 21.1%id, 0.0%wa, 0.0%hi, 0.0%si, 0.0%st Cpu10 : 77.6%us, 1.7%sy, 0.0%ni, 20.8%id, 0.0%wa, 0.0%hi, 0.0%si, 0.0%st Cpu11 : 75.7%us, 2.0%sy, 0.0%ni, 21.4%id, 1.0%wa, 0.0%hi, 0.0%si, 0.0%st Cpu12 : 76.6%us, 2.3%sy, 0.0%ni, 21.1%id, 0.0%wa, 0.0%hi, 0.0%si, 0.0%st Cpu13 : 76.6%us, 2.3%sy, 0.0%ni, 21.1%id, 0.0%wa, 0.0%hi, 0.0%si, 0.0%st Cpu14 : 76.2%us, 2.6%sy, 0.0%ni, 15.9%id, 5.3%wa, 0.0%hi, 0.0%si, 0.0%st Cpu15 : 76.6%us, 2.0%sy, 0.0%ni, 21.5%id, 0.0%wa, 0.0%hi, 0.0%si, 0.0%st Cpu16 : 73.6%us, 2.6%sy, 0.0%ni, 23.8%id, 0.0%wa, 0.0%hi, 0.0%si, 0.0%st Cpu17 : 74.5%us, 2.3%sy, 0.0%ni, 23.2%id, 0.0%wa, 0.0%hi, 0.0%si, 0.0%st Cpu18 : 73.9%us, 2.3%sy, 0.0%ni, 23.8%id, 0.0%wa, 0.0%hi, 0.0%si, 0.0%st Cpu19 : 72.9%us, 2.6%sy, 0.0%ni, 24.4%id, 0.0%wa, 0.0%hi, 0.0%si, 0.0%st Cpu20 : 72.8%us, 2.6%sy, 0.0%ni, 24.5%id, 0.0%wa, 0.0%hi, 0.0%si, 0.0%st Cpu21 : 72.7%us, 2.3%sy, 0.0%ni, 25.0%id, 0.0%wa, 0.0%hi, 0.0%si, 0.0%st Cpu22 : 72.5%us, 2.6%sy, 0.0%ni, 24.8%id, 0.0%wa, 0.0%hi, 0.0%si, 0.0%st Cpu23 : 73.0%us, 2.3%sy, 0.0%ni, 24.7%id, 0.0%wa, 0.0%hi, 0.0%si, 0.0%st Cpu24 : 74.7%us, 2.7%sy, 0.0%ni, 22.7%id, 0.0%wa, 0.0%hi, 0.0%si, 0.0%st Cpu25 : 74.5%us, 2.6%sy, 0.0%ni, 22.8%id, 0.0%wa, 0.0%hi, 0.0%si, 0.0%st Cpu26 : 73.7%us, 2.0%sy, 0.0%ni, 24.3%id, 0.0%wa, 0.0%hi, 0.0%si, 0.0%st Cpu27 : 74.1%us, 2.3%sy, 0.0%ni, 23.6%id, 0.0%wa, 0.0%hi, 0.0%si, 0.0%st Cpu28 : 74.1%us, 2.3%sy, 0.0%ni, 23.6%id, 0.0%wa, 0.0%hi, 0.0%si, 0.0%st Cpu29 : 74.0%us, 2.0%sy, 0.0%ni, 24.0%id, 0.0%wa, 0.0%hi, 0.0%si, 0.0%st Cpu30 : 73.2%us, 2.3%sy, 0.0%ni, 24.5%id, 0.0%wa, 0.0%hi, 0.0%si, 0.0%st Cpu31 : 73.1%us, 2.0%sy, 0.0%ni, 24.9%id, 0.0%wa, 0.0%hi, 0.0%si, 0.0%st Mem: 132138168k total, 131711704k used, 426464k free, 88336k buffers Swap: 5701624k total, 229572k used, 5472052k free, 13745596k cached PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND 13865 root 20 0 122g 112g 3.1g S 2334.3 89.6 20726:49 java 27139 jayen 20 0 15428 1728 952 S 2.6 0.0 0:04.21 top 27161 sysadmin 20 0 15428 1712 940 R 1.0 0.0 0:00.28 top 33 root 20 0 0 0 0 S 0.3 0.0 0:06.24 ksoftirqd/7 131 root 20 0 0 0 0 S 0.3 0.0 0:09.52 events/0 1858 root 20 0 0 0 0 S 0.3 0.0 1:35.14 kondemand/0 A dump of the java stack confirms that none of the threads are anywhere near the few places where locks are used, nor are they anywhere near any disk or network i/o. I had trouble finding a clear explanation of what 'top' means by "idle" versus "wait", but I get the impression that "idle" means "no more threads that need to be run" but this doesn't make sense in our case. We're using a "Executors.newFixedThreadPool(30)". There are a large number of tasks pending and each task lasts for 10 seconds or so. I suspect that the explanation requires a good understanding of NUMA. Is the "idle" state what you see when a CPU is waiting for a non-local access? If not, then what is the explanation?

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  • Integrating JavaScript Unit Tests with Visual Studio

    - by Stephen Walther
    Modern ASP.NET web applications take full advantage of client-side JavaScript to provide better interactivity and responsiveness. If you are building an ASP.NET application in the right way, you quickly end up with lots and lots of JavaScript code. When writing server code, you should be writing unit tests. One big advantage of unit tests is that they provide you with a safety net that enable you to safely modify your existing code – for example, fix bugs, add new features, and make performance enhancements -- without breaking your existing code. Every time you modify your code, you can execute your unit tests to verify that you have not broken anything. For the same reason that you should write unit tests for your server code, you should write unit tests for your client code. JavaScript is just as susceptible to bugs as C#. There is no shortage of unit testing frameworks for JavaScript. Each of the major JavaScript libraries has its own unit testing framework. For example, jQuery has QUnit, Prototype has UnitTestJS, YUI has YUI Test, and Dojo has Dojo Objective Harness (DOH). The challenge is integrating a JavaScript unit testing framework with Visual Studio. Visual Studio and Visual Studio ALM provide fantastic support for server-side unit tests. You can easily view the results of running your unit tests in the Visual Studio Test Results window. You can set up a check-in policy which requires that all unit tests pass before your source code can be committed to the source code repository. In addition, you can set up Team Build to execute your unit tests automatically. Unfortunately, Visual Studio does not provide “out-of-the-box” support for JavaScript unit tests. MS Test, the unit testing framework included in Visual Studio, does not support JavaScript unit tests. As soon as you leave the server world, you are left on your own. The goal of this blog entry is to describe one approach to integrating JavaScript unit tests with MS Test so that you can execute your JavaScript unit tests side-by-side with your C# unit tests. The goal is to enable you to execute JavaScript unit tests in exactly the same way as server-side unit tests. You can download the source code described by this project by scrolling to the end of this blog entry. Rejected Approach: Browser Launchers One popular approach to executing JavaScript unit tests is to use a browser as a test-driver. When you use a browser as a test-driver, you open up a browser window to execute and view the results of executing your JavaScript unit tests. For example, QUnit – the unit testing framework for jQuery – takes this approach. The following HTML page illustrates how you can use QUnit to create a unit test for a function named addNumbers(). <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> <html> <head> <title>Using QUnit</title> <link rel="stylesheet" href="http://github.com/jquery/qunit/raw/master/qunit/qunit.css" type="text/css" /> </head> <body> <h1 id="qunit-header">QUnit example</h1> <h2 id="qunit-banner"></h2> <div id="qunit-testrunner-toolbar"></div> <h2 id="qunit-userAgent"></h2> <ol id="qunit-tests"></ol> <div id="qunit-fixture">test markup, will be hidden</div> <script type="text/javascript" src="http://code.jquery.com/jquery-latest.js"></script> <script type="text/javascript" src="http://github.com/jquery/qunit/raw/master/qunit/qunit.js"></script> <script type="text/javascript"> // The function to test function addNumbers(a, b) { return a+b; } // The unit test test("Test of addNumbers", function () { equals(4, addNumbers(1,3), "1+3 should be 4"); }); </script> </body> </html> This test verifies that calling addNumbers(1,3) returns the expected value 4. When you open this page in a browser, you can see that this test does, in fact, pass. The idea is that you can quickly refresh this QUnit HTML JavaScript test driver page in your browser whenever you modify your JavaScript code. In other words, you can keep a browser window open and keep refreshing it over and over while you are developing your application. That way, you can know very quickly whenever you have broken your JavaScript code. While easy to setup, there are several big disadvantages to this approach to executing JavaScript unit tests: You must view your JavaScript unit test results in a different location than your server unit test results. The JavaScript unit test results appear in the browser and the server unit test results appear in the Visual Studio Test Results window. Because all of your unit test results don’t appear in a single location, you are more likely to introduce bugs into your code without noticing it. Because your unit tests are not integrated with Visual Studio – in particular, MS Test -- you cannot easily include your JavaScript unit tests when setting up check-in policies or when performing automated builds with Team Build. A more sophisticated approach to using a browser as a test-driver is to automate the web browser. Instead of launching the browser and loading the test code yourself, you use a framework to automate this process. There are several different testing frameworks that support this approach: · Selenium – Selenium is a very powerful framework for automating browser tests. You can create your tests by recording a Firefox session or by writing the test driver code in server code such as C#. You can learn more about Selenium at http://seleniumhq.org/. LTAF – The ASP.NET team uses the Lightweight Test Automation Framework to test JavaScript code in the ASP.NET framework. You can learn more about LTAF by visiting the project home at CodePlex: http://aspnet.codeplex.com/releases/view/35501 jsTestDriver – This framework uses Java to automate the browser. jsTestDriver creates a server which can be used to automate multiple browsers simultaneously. This project is located at http://code.google.com/p/js-test-driver/ TestSwam – This framework, created by John Resig, uses PHP to automate the browser. Like jsTestDriver, the framework creates a test server. You can open multiple browsers that are automated by the test server. Learn more about TestSwarm by visiting the following address: https://github.com/jeresig/testswarm/wiki Yeti – This is the framework introduced by Yahoo for automating browser tests. Yeti uses server-side JavaScript and depends on Node.js. Learn more about Yeti at http://www.yuiblog.com/blog/2010/08/25/introducing-yeti-the-yui-easy-testing-interface/ All of these frameworks are great for integration tests – however, they are not the best frameworks to use for unit tests. In one way or another, all of these frameworks depend on executing tests within the context of a “living and breathing” browser. If you create an ASP.NET Unit Test then Visual Studio will launch a web server before executing the unit test. Why is launching a web server so bad? It is not the worst thing in the world. However, it does introduce dependencies that prevent your code from being tested in isolation. One of the defining features of a unit test -- versus an integration test – is that a unit test tests code in isolation. Another problem with launching a web server when performing unit tests is that launching a web server can be slow. If you cannot execute your unit tests quickly, you are less likely to execute your unit tests each and every time you make a code change. You are much more likely to fall into the pit of failure. Launching a browser when performing a JavaScript unit test has all of the same disadvantages as launching a web server when performing an ASP.NET unit test. Instead of testing a unit of JavaScript code in isolation, you are testing JavaScript code within the context of a particular browser. Using the frameworks listed above for integration tests makes perfect sense. However, I want to consider a different approach for creating unit tests for JavaScript code. Using Server-Side JavaScript for JavaScript Unit Tests A completely different approach to executing JavaScript unit tests is to perform the tests outside of any browser. If you really want to test JavaScript then you should test JavaScript and leave the browser out of the testing process. There are several ways that you can execute JavaScript on the server outside the context of any browser: Rhino – Rhino is an implementation of JavaScript written in Java. The Rhino project is maintained by the Mozilla project. Learn more about Rhino at http://www.mozilla.org/rhino/ V8 – V8 is the open-source Google JavaScript engine written in C++. This is the JavaScript engine used by the Chrome web browser. You can download V8 and embed it in your project by visiting http://code.google.com/p/v8/ JScript – JScript is the JavaScript Script Engine used by Internet Explorer (up to but not including Internet Explorer 9), Windows Script Host, and Active Server Pages. Internet Explorer is still the most popular web browser. Therefore, I decided to focus on using the JScript Script Engine to execute JavaScript unit tests. Using the Microsoft Script Control There are two basic ways that you can pass JavaScript to the JScript Script Engine and execute the code: use the Microsoft Windows Script Interfaces or use the Microsoft Script Control. The difficult and proper way to execute JavaScript using the JScript Script Engine is to use the Microsoft Windows Script Interfaces. You can learn more about the Script Interfaces by visiting http://msdn.microsoft.com/en-us/library/t9d4xf28(VS.85).aspx The main disadvantage of using the Script Interfaces is that they are difficult to use from .NET. There is a great series of articles on using the Script Interfaces from C# located at http://www.drdobbs.com/184406028. I picked the easier alternative and used the Microsoft Script Control. The Microsoft Script Control is an ActiveX control that provides a higher level abstraction over the Window Script Interfaces. You can download the Microsoft Script Control from here: http://www.microsoft.com/downloads/en/details.aspx?FamilyID=d7e31492-2595-49e6-8c02-1426fec693ac After you download the Microsoft Script Control, you need to add a reference to it to your project. Select the Visual Studio menu option Project, Add Reference to open the Add Reference dialog. Select the COM tab and add the Microsoft Script Control 1.0. Using the Script Control is easy. You call the Script Control AddCode() method to add JavaScript code to the Script Engine. Next, you call the Script Control Run() method to run a particular JavaScript function. The reference documentation for the Microsoft Script Control is located at the MSDN website: http://msdn.microsoft.com/en-us/library/aa227633%28v=vs.60%29.aspx Creating the JavaScript Code to Test To keep things simple, let’s imagine that you want to test the following JavaScript function named addNumbers() which simply adds two numbers together: MvcApplication1\Scripts\Math.js function addNumbers(a, b) { return 5; } Notice that the addNumbers() method always returns the value 5. Right-now, it will not pass a good unit test. Create this file and save it in your project with the name Math.js in your MVC project’s Scripts folder (Save the file in your actual MVC application and not your MVC test application). Creating the JavaScript Test Helper Class To make it easier to use the Microsoft Script Control in unit tests, we can create a helper class. This class contains two methods: LoadFile() – Loads a JavaScript file. Use this method to load the JavaScript file being tested or the JavaScript file containing the unit tests. ExecuteTest() – Executes the JavaScript code. Use this method to execute a JavaScript unit test. Here’s the code for the JavaScriptTestHelper class: JavaScriptTestHelper.cs   using System; using System.IO; using Microsoft.VisualStudio.TestTools.UnitTesting; using MSScriptControl; namespace MvcApplication1.Tests { public class JavaScriptTestHelper : IDisposable { private ScriptControl _sc; private TestContext _context; /// <summary> /// You need to use this helper with Unit Tests and not /// Basic Unit Tests because you need a Test Context /// </summary> /// <param name="testContext">Unit Test Test Context</param> public JavaScriptTestHelper(TestContext testContext) { if (testContext == null) { throw new ArgumentNullException("TestContext"); } _context = testContext; _sc = new ScriptControl(); _sc.Language = "JScript"; _sc.AllowUI = false; } /// <summary> /// Load the contents of a JavaScript file into the /// Script Engine. /// </summary> /// <param name="path">Path to JavaScript file</param> public void LoadFile(string path) { var fileContents = File.ReadAllText(path); _sc.AddCode(fileContents); } /// <summary> /// Pass the path of the test that you want to execute. /// </summary> /// <param name="testMethodName">JavaScript function name</param> public void ExecuteTest(string testMethodName) { dynamic result = null; try { result = _sc.Run(testMethodName, new object[] { }); } catch { var error = ((IScriptControl)_sc).Error; if (error != null) { var description = error.Description; var line = error.Line; var column = error.Column; var text = error.Text; var source = error.Source; if (_context != null) { var details = String.Format("{0} \r\nLine: {1} Column: {2}", source, line, column); _context.WriteLine(details); } } throw new AssertFailedException(error.Description); } } public void Dispose() { _sc = null; } } }     Notice that the JavaScriptTestHelper class requires a Test Context to be instantiated. For this reason, you can use the JavaScriptTestHelper only with a Visual Studio Unit Test and not a Basic Unit Test (These are two different types of Visual Studio project items). Add the JavaScriptTestHelper file to your MVC test application (for example, MvcApplication1.Tests). Creating the JavaScript Unit Test Next, we need to create the JavaScript unit test function that we will use to test the addNumbers() function. Create a folder in your MVC test project named JavaScriptTests and add the following JavaScript file to this folder: MvcApplication1.Tests\JavaScriptTests\MathTest.js /// <reference path="JavaScriptUnitTestFramework.js"/> function testAddNumbers() { // Act var result = addNumbers(1, 3); // Assert assert.areEqual(4, result, "addNumbers did not return right value!"); }   The testAddNumbers() function takes advantage of another JavaScript library named JavaScriptUnitTestFramework.js. This library contains all of the code necessary to make assertions. Add the following JavaScriptnitTestFramework.js to the same folder as the MathTest.js file: MvcApplication1.Tests\JavaScriptTests\JavaScriptUnitTestFramework.js var assert = { areEqual: function (expected, actual, message) { if (expected !== actual) { throw new Error("Expected value " + expected + " is not equal to " + actual + ". " + message); } } }; There is only one type of assertion supported by this file: the areEqual() assertion. Most likely, you would want to add additional types of assertions to this file to make it easier to write your JavaScript unit tests. Deploying the JavaScript Test Files This step is non-intuitive. When you use Visual Studio to run unit tests, Visual Studio creates a new folder and executes a copy of the files in your project. After you run your unit tests, your Visual Studio Solution will contain a new folder named TestResults that includes a subfolder for each test run. You need to configure Visual Studio to deploy your JavaScript files to the test run folder or Visual Studio won’t be able to find your JavaScript files when you execute your unit tests. You will get an error that looks something like this when you attempt to execute your unit tests: You can configure Visual Studio to deploy your JavaScript files by adding a Test Settings file to your Visual Studio Solution. It is important to understand that you need to add this file to your Visual Studio Solution and not a particular Visual Studio project. Right-click your Solution in the Solution Explorer window and select the menu option Add, New Item. Select the Test Settings item and click the Add button. After you create a Test Settings file for your solution, you can indicate that you want a particular folder to be deployed whenever you perform a test run. Select the menu option Test, Edit Test Settings to edit your test configuration file. Select the Deployment tab and select your MVC test project’s JavaScriptTest folder to deploy. Click the Apply button and the Close button to save the changes and close the dialog. Creating the Visual Studio Unit Test The very last step is to create the Visual Studio unit test (the MS Test unit test). Add a new unit test to your MVC test project by selecting the menu option Add New Item and selecting the Unit Test project item (Do not select the Basic Unit Test project item): The difference between a Basic Unit Test and a Unit Test is that a Unit Test includes a Test Context. We need this Test Context to use the JavaScriptTestHelper class that we created earlier. Enter the following test method for the new unit test: [TestMethod] public void TestAddNumbers() { var jsHelper = new JavaScriptTestHelper(this.TestContext); // Load JavaScript files jsHelper.LoadFile("JavaScriptUnitTestFramework.js"); jsHelper.LoadFile(@"..\..\..\MvcApplication1\Scripts\Math.js"); jsHelper.LoadFile("MathTest.js"); // Execute JavaScript Test jsHelper.ExecuteTest("testAddNumbers"); } This code uses the JavaScriptTestHelper to load three files: JavaScripUnitTestFramework.js – Contains the assert functions. Math.js – Contains the addNumbers() function from your MVC application which is being tested. MathTest.js – Contains the JavaScript unit test function. Next, the test method calls the JavaScriptTestHelper ExecuteTest() method to execute the testAddNumbers() JavaScript function. Running the Visual Studio JavaScript Unit Test After you complete all of the steps described above, you can execute the JavaScript unit test just like any other unit test. You can use the keyboard combination CTRL-R, CTRL-A to run all of the tests in the current Visual Studio Solution. Alternatively, you can use the buttons in the Visual Studio toolbar to run the tests: (Unfortunately, the Run All Impacted Tests button won’t work correctly because Visual Studio won’t detect that your JavaScript code has changed. Therefore, you should use either the Run Tests in Current Context or Run All Tests in Solution options instead.) The results of running the JavaScript tests appear side-by-side with the results of running the server tests in the Test Results window. For example, if you Run All Tests in Solution then you will get the following results: Notice that the TestAddNumbers() JavaScript test has failed. That is good because our addNumbers() function is hard-coded to always return the value 5. If you double-click the failing JavaScript test, you can view additional details such as the JavaScript error message and the line number of the JavaScript code that failed: Summary The goal of this blog entry was to explain an approach to creating JavaScript unit tests that can be easily integrated with Visual Studio and Visual Studio ALM. I described how you can use the Microsoft Script Control to execute JavaScript on the server. By taking advantage of the Microsoft Script Control, we were able to execute our JavaScript unit tests side-by-side with all of our other unit tests and view the results in the standard Visual Studio Test Results window. You can download the code discussed in this blog entry from here: http://StephenWalther.com/downloads/Blog/JavaScriptUnitTesting/JavaScriptUnitTests.zip Before running this code, you need to first install the Microsoft Script Control which you can download from here: http://www.microsoft.com/downloads/en/details.aspx?FamilyID=d7e31492-2595-49e6-8c02-1426fec693ac

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