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• JavaDay Taipei 2014 Trip Report

  - by reza_rahman

  JavaDay Taipei 2014 was held at the Taipei International Convention Center on August 1st. Organized by Oracle University, it is one of the largest Java developer events in Taiwan. This was another successful year for JavaDay Taipei with a fully sold out venue packed with youthful, energetic developers (this was my second time at the event and I have already been invited to speak again next year!). In addition to Oracle speakers like me, Steve Chin and Naveen Asrani, the event also featured a bevy of local speakers including Taipei Java community leaders. Topics included Java SE, Java EE, JavaFX, cloud and Big Data. It was my pleasure and privilege to present one of the opening keynotes for the event. I presented my session on Java EE titled "JavaEE.Next(): Java EE 7, 8, and Beyond". I covered the changes in Java EE 7 as well as what's coming in Java EE 8. I demoed the Cargo Tracker Java EE BluePrints. I also briefly talked about Adopt-a-JSR for Java EE 8. The slides for the keynote are below (click here to download and view the actual PDF): It appears your Web browser is not configured to display PDF files. No worries, just click here to download the PDF file. In the afternoon I did my JavaScript + Java EE 7 talk titled "Using JavaScript/HTML5 Rich Clients with Java EE 7". This talk is basically about aligning EE 7 with the emerging JavaScript ecosystem (specifically AngularJS). The talk was completely packed. The slide deck for the talk is here: JavaScript/HTML5 Rich Clients Using Java EE 7 from Reza Rahman The demo application code is posted on GitHub. The code should be a helpful resource if this development model is something that interests you. Do let me know if you need help with it but the instructions should be fairly self-explanatory. I am delivering this material at JavaOne 2014 as a two-hour tutorial. This should give me a little more bandwidth to dig a little deeper, especially on the JavaScript end. I finished off Java Day Taipei with my talk titled "Using NoSQL with ~JPA, EclipseLink and Java EE" (this was the last session of the conference). The talk covers an interesting gap that there is surprisingly little material on out there. The talk has three parts -- a birds-eye view of the NoSQL landscape, how to use NoSQL via a JPA centric facade using EclipseLink NoSQL, Hibernate OGM, DataNucleus, Kundera, Easy-Cassandra, etc and how to use NoSQL native APIs in Java EE via CDI. The slides for the talk are here: Using NoSQL with ~JPA, EclipseLink and Java EE from Reza Rahman The JPA based demo is available here, while the CDI based demo is available here. Both demos use MongoDB as the data store. Do let me know if you need help getting the demos up and running. After the event the Oracle University folks hosted a reception in the evening which was very well attended by organizers, speakers and local Java community leaders. I am extremely saddened by the fact that this otherwise excellent trip was scarred by terrible tragedy. After the conference I joined a few folks for a hike on the Maokong Mountain on Saturday. The group included friends in the Taiwanese Java community including Ian and Robbie Cheng. Without warning, fatal tragedy struck on a remote part of the trail. Despite best efforts by us, the excellent Taiwanese Emergency Rescue Team and World class Taiwanese physicians we were unable to save our friend Robbie Cheng's life. Robbie was just thirty-four years old and is survived by his younger brother, mother and father. Being the father of a young child myself, I can only imagine the deep sorrow that this senseless loss unleashes. Robbie was a key member of the Taiwanese Java community and a Java Evangelist at Sun at one point. Ironically the only picture I was able to take of the trail was mere moments before tragedy. I thought I should place him in that picture in profoundly respectful memoriam: Perhaps there is some solace in the fact that there is something inherently honorable in living a bright life, dying young and meeting one's end on a beautiful remote mountain trail few venture to behold let alone attempt to ascend in a long and tired lifetime. Perhaps I'd even say it's a fate I would not entirely regret facing if it were my own. With that thought in mind it seems appropriate to me to quote some lyrics from the song "Runes to My Memory" by legendary Swedish heavy metal band Amon Amarth idealizing a fallen Viking warrior cut down in his prime: "Here I lie on wet sand I will not make it home I clench my sword in my hand Say farewell to those I love When I am dead Lay me in a mound Place my weapons by my side For the journey to Hall up high When I am dead Lay me in a mound Raise a stone for all to see Runes carved to my memory" I submit my deepest condolences to Robbie's family and hope my next trip to Taiwan ends in a less somber note.

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• Take Two: Comparing JVMs on ARM/Linux

  - by user12608080

  Although the intent of the previous article, entitled Comparing JVMs on ARM/Linux, was to introduce and highlight the availability of the HotSpot server compiler (referred to as c2) for Java SE-Embedded ARM v7,  it seems, based on feedback, that everyone was more interested in the OpenJDK comparisons to Java SE-E.  In fact there were two main concerns: The fact that the previous article compared Java SE-E 7 against OpenJDK 6 might be construed as an unlevel playing field because version 7 is newer and therefore potentially more optimized. That the generic compiler settings chosen to build the OpenJDK implementations did not put those versions in a particularly favorable light. With those considerations in mind, we'll institute the following changes to this version of the benchmarking: In order to help alleviate an additional concern that there is some sort of benchmark bias, we'll use a different suite, called DaCapo.  Funded and supported by many prestigious organizations, DaCapo's aim is to benchmark real world applications.  Further information about DaCapo can be found at http://dacapobench.org. At the suggestion of Xerxes Ranby, who has been a great help through this entire exercise, a newer Linux distribution will be used to assure that the OpenJDK implementations were built with more optimal compiler settings.  The Linux distribution in this instance is Ubuntu 11.10 Oneiric Ocelot. Having experienced difficulties getting Ubuntu 11.10 to run on the original D2Plug ARMv7 platform, for these benchmarks, we'll switch to an embedded system that has a supported Ubuntu 11.10 release.  That platform is the Freescale i.MX53 Quick Start Board.  It has an ARMv7 Coretex-A8 processor running at 1GHz with 1GB RAM. We'll limit comparisons to 4 JVM implementations: Java SE-E 7 Update 2 c1 compiler (default) Java SE-E 6 Update 30 (c1 compiler is the only option) OpenJDK 6 IcedTea6 1.11pre 6b23~pre11-0ubuntu1.11.10.2 CACAO build 1.1.0pre2 OpenJDK 6 IcedTea6 1.11pre 6b23~pre11-0ubuntu1.11.10.2 JamVM build-1.6.0-devel Certain OpenJDK implementations were eliminated from this round of testing for the simple reason that their performance was not competitive.  The Java SE 7u2 c2 compiler was also removed because although quite respectable, it did not perform as well as the c1 compilers.  Recall that c2 works optimally in long-lived situations.  Many of these benchmarks completed in a relatively short period of time.  To get a feel for where c2 shines, take a look at the first chart in this blog. The first chart that follows includes performance of all benchmark runs on all platforms.  Later on we'll look more at individual tests.  In all runs, smaller means faster.  The DaCapo aficionado may notice that only 10 of the 14 DaCapo tests for this version were executed.  The reason for this is that these 10 tests represent the only ones successfully completed by all 4 JVMs.  Only the Java SE-E 6u30 could successfully run all of the tests.  Both OpenJDK instances not only failed to complete certain tests, but also experienced VM aborts too. One of the first observations that can be made between Java SE-E 6 and 7 is that, for all intents and purposes, they are on par with regards to performance.  While it is a fact that successive Java SE releases add additional optimizations, it is also true that Java SE 7 introduces additional complexity to the Java platform thus balancing out any potential performance gains at this point.  We are still early into Java SE 7.  We would expect further performance enhancements for Java SE-E 7 in future updates. In comparing Java SE-E to OpenJDK performance, among both OpenJDK VMs, Cacao results are respectable in 4 of the 10 tests.  The charts that follow show the individual results of those four tests.  Both Java SE-E versions do win every test and outperform Cacao in the range of 9% to 55%. For the remaining 6 tests, Java SE-E significantly outperforms Cacao in the range of 114% to 311% So it looks like OpenJDK results are mixed for this round of benchmarks.  In some cases, performance looks to have improved.  But in a majority of instances, OpenJDK still lags behind Java SE-Embedded considerably. Time to put on my asbestos suit.  Let the flames begin...

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• The Apple iPad &ndash; I&rsquo;m gonna get it!

  - by Sahil Malik

  Ad:: SharePoint 2007 Training in .NET 3.5 technologies (more information). Well, heck, here comes another non-techie blogpost. You know I’m a geek, so I love gadgets! I found it RATHER interesting to see all the negative news on the blogosphere about the iPad. The main bitch points are - No Multi tasking No Flash Just a bigger iPhone. So here’s the deal! My view is, the above 3 are EXACTLY what I had personally hoped for in the Apple iPad. Before the release, I had gone on the record saying - “If the Apple Tablet is able to run full fledged iTunes (so I can get rid of iTunes on my desktop, I don’t like iTunes on Windows), can browse the net, can read PDFs, and will be under $1000, I’ll buy it”. Well, so, the released iPad wasn’t exactly like my dream tablet. The biggest downer IMO was it’s inability to run full iTunes. But, really, in retrospect, I like the newly released iPad. And here is why. No Multi tasking and No Flash, means much better battery life. Frankly, I rarely multi task on my laptop/desktop .. yeah I know my OS does .. but ME – I don’t multi task, and I don’t think you do either!! As I type this blogpost, I have a few windows running behind the scenes, but they are simply waiting for me to get back to them. The only thing truly running and I am making use of, other than this blogost, is media player playing some music – which the iPad can do. Also, I am logged into IM/Email – which again, iPad can do via notifications. It does the limited multitasking I need, without chewing down on batteries. Smart thinking, precisely the reason I love the iPhone. I don’t want a bulky battery consuming machine. Lack of flash? Okay sure, I can’t see Hulu on my iPad. That’s some loss. I can see youtube. Also, per Adobe I can’t see some porn sites, which I don’t want to see on my iPad. But, Flash is heavy. Especially flash video. My dream is to see silverlight run on the iPhone and iPad. No flash = not such a big loss. Speaking of battery life – 10 hours is plenty. I haven’t been away from electricity for that long usually, so I’m okay with charging it up when it runs low. It’s really not such a big deal honestly. Finally, eBook functionality – wow! I went on the record saying, eBook readers are not for me, but seriously, the iPad is perfect for my eBook needs at least. And as far it being just a bigger iPhone? I’ve always wanted a bigger iPhone, precisely for the eBook reading experience. I love my iPhone, I love the apps on it. The only thing that sucks about the iPhone is battery life, but other than that, it is the best gadget I have ever bought! And something that runs on mobile chips, is that thin, and those newly written apps .. mail, calendar .. I am very very excited to get my iPad, which will be the 64gig 3G version. The biggest plus in an iPad ……… no contract on data. I am *hoping*, this means that I can buy a SIM card in Europe, and use the iPad here. That would be killer awesome! But hey, if I had to pick downers in the iPad, they would be - - I wish they had a 128G Version. Now that we have a good video viewing machine, I know I’d chew up space quickly.- Sync over WIFI, seriously Apple.  Both for iPhone and iPad.- 3 month wait!!- Existing iPhone users should get a discount on the iPad data plan. Comment on the article ....

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• Managing Your First SharePoint Project or Team

  - by Mark Rackley

  (*editor’s note* If you have proper SharePoint Training, know the difference between a site and a site collection, and have the utmost respect for the knowledge of your SharePoint team skip this blog and go directly to meetdux.com, do not pass go, do not collect $200… otherwise, please proceed) Dear Mr. or Mrs. I-know-nothing-about-SharePoint-but-hey,-I-have-manager-in-my-title-so-I’ll-tell-you-how-to-your-job, Thank you so much for joining the Acme corporation. We appreciate your eagerness and willingness to jump in and help us accomplish all of our goals here at acme (these roadrunner rockets don’t make themselves). You may have noticed that we have this thing called SharePoint lying around and we have invested some time in money to make it not a complete piece of garbage. So, I thought I’d give you some pointers to help make your stay here enjoyable and productive. Yeah… you don’t really know SharePoint Just because you had a mysite at your last organization or had a SharePoint 2003 team site does NOT mean you comprehend the vastness that is SharePoint. You don’t know what’s going on behind the scenes. You don’t know what should and should not be done. No, we CAN’T just query the SQL database directly. Yes, it really does take that long. No, we can’t do that out-of-the-box. Your experience doesn’t mean as much as you think it means… Yes, I’m aware that you co-created the internet with Al Gore and have been managing projects since I was blowing up GI Joe figures with firecrackers, however SharePoint is not like anything you have worked with before from a management perspective. Please don’t tell us the proper way to do our job or tell us how “you” would do it, and PLEASE don’t utter the words “I used to do some .NET development so let me know if you get stuck and need some guidance.” It MAY be possible for a incredible project manager to manage a SharePoint project and not understand the technology, but if you force your ideas on us or treat us like we don’t really know what we’re doing then you will prove yourself to NOT be one of those types. Oh no you didn’t… Please don’t tell us how you can bring in a group of guys of Kazakhstan to do the project for $20/hr. There are many companies out there who can do some really crappy SharePoint work and we don’t want to be stuck maintaining their junk. Do you know what it means to deploy a solution? Neither do some of those companies out there. However, there are are few AWESOME consulting firms out there but $150/hr is cheap for these guys. Believe me, it’s worth it though. You get what you pay for! Show us some respect We truly do appreciate and value your opinion and experience, but when we tell you something is different in SharePoint don’t be condescending and dismiss OUR experience and opinions. We have spent a lot of time and energy learning a very complicated technology that can open up a world of possibilities when used properly. We just want to make sure it is used properly. It’s not the same as .NET development. It’s not like a regular web application. There’s more going on behind the scenes than you can possibly fathom. Have a little faith in us please and listen when we talk. You may actually learn a thing or two. Take some time to learn the technology There is hope… you don’t have to be totally worthless. Take some time to learn SharePoint. Learn what it is and what it can do. Invest some time in learning our SharePoint environment. What’s our logical architecture and taxonomy? What governance do we have in place? If you just thought “huh?” then yes, I’m talking to you. Sincerely, Your SharePoint Team (This rant is not pointed at any particular organization or person. If you think it’s about you, you are wrong. This is just a general rant based upon things people have told me and things I’ve seen. If you don’t think it applies to you, please move on. If you think you might be guilty of handling your SharePoint team the wrong way, then just please listen, learn, and have a little faith in your team. You all have the same goal in mind. Also, take the time to learn something about SharePoint, you will all be less frustrated with each other.)

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• Easiest, most fun way to program 2D games? Flash? XNA? Some other engine?

  - by Maxi

  Hi, this is a post detailing my search for the most enjoyable way for a hobbyist game programmer to sweeten his free time with making a game. My requirements: I looked at Flash first, I made a couple of small games but I'm doubtful of the performance. I would like to make a fairly large strategy game, with several hundred units fighting simultaneously, explosions and animations included. Also zoomable maps. I saw that Adobe has a new 3D API for Flash, but I don't know if that improves 2D performance aswell, I couldn't find anything related to that question on their MAX10 sessions. Would you say that Flash is a good technology for making large 2D games easily? I really like Actionscript, and I love how easy everything is in Flash. There are several engines available which make it even easier. I just do this for fun, and it would be even better if there were proper animation/particle editors available and if the engine I were to use, would be available for multiple platforms. (so more people can play my game once finished). I'd like to have it available on many mobile platforms aswell. (because I love touch input for some reason) I do know the XNA framework pretty well, but there are no good engines available for it, and it will only run on Windows, which is a huge turn off. Even bigger is, that you need to install the XNA redistributable each time you want to give the game to someone. If I use XNA, I would have to make all the tools myself, and I'd probably have to make them with WPF. (I'd love to make tools with Adobe AIR, but unfortunately the API's for image manipulation etc. are far worse in Flash, than they are in XNA/WPF.) Now, I'm aware that I could make my own engine that supports each of those platforms, but quite frankly, that would be too much work plowing through APIs. After all, I want to make a game, not an engine. So the question becomes: Is there maybe a cross platform (free or free to develop?) engine available that I could use for 2D development? I prefer: C#, Actionscript. I don't mind using c++ if the toolset is above average, but I highly doubt that there is something out there like that. Please prove me wrong :) So summary: I'd like to use Flash, but I don't know if it scales well enough. I'm not a scripter, I want some real APIs that I can work with inside a proper IDE. Just for information, I looked at several alternatives, I'm actually looking for a long time already. You'd help me a lot to make a decision finally. Feature-wise the Flatredball engine would be ideal. But I tried their tools, and quite frankly, they are horrible. Absolutely unusable, I'd need to make my own for sure. I didn't look at their API, but if their tools are so bad, I'm not inclined to look further. Unity3D. This one is quite nice, but I really don't need 3D, and it is quite ...a lot of work to learn. I also don't like that it is so expensive to use for different platforms and that I can only code for it through scripting. You have to buy each platform separately. The editor usability is average, the product overall is good enough for most purposes, but learning it myself would be overkill. Shiva 3D. It looks good enough, but again: I don't really need 3D. The editor usability is a little worse than Unity3D in my opinion and it wasn't clear to me how to start programming. I think it requires C++ for coding, so that's a negative too. I want to have fun, and c# is fun ;) SDL. Quite frankly, I'd still need to port to all those different SDL implementations. And I don't like OpenGL style programming, it's just plain ugly. And it needs c++, I know that there might be some wrappers available, but I don't like to use wrappers, because... Irrlicht. A lot of features, but support seems to be low and it is aimed at enthusiasts. C# bindings get dropped repeatedly. I'm not an engine enthusiast, I just want to make a game. I don't see this happening with Irrlicht. Ogre3D. Way too much work, it's just a graphics engine. Also no multiple platform support and c++. Torque2D. Costs something to use, and I didn't hear a lot of good things about support and documentation. Also costs extra for each platform.

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• A Patent for Workload Management Based on Service Level Objectives

  - by jsavit

  I'm very pleased to announce that after a tiny :-) wait of about 5 years, my patent application for a workload manager was finally approved. Background Many operating systems have a resource manager which lets you control machine resources. For example, Solaris provides controls for CPU with several options: shares for proportional CPU allocation. If you have twice as many shares as me, and we are competing for CPU, you'll get about twice as many CPU cycles), dedicated CPU allocation in which a number of CPUs are exclusively dedicated to an application's use. You can say that a zone or project "owns" 8 CPUs on a 32 CPU machine, for example. And, capped CPU in which you specify the upper bound, or cap, of how much CPU an application gets. For example, you can throttle an application to 0.125 of a CPU. (This isn't meant to be an exhaustive list of Solaris RM controls.) Workload management Useful as that is (and tragic that some other operating systems have little resource management and isolation, and frighten people into running only 1 app per OS instance - and wastefully size every server for the peak workload it might experience) that's not really workload management. With resource management one controls the resources, and hope that's enough to meet application service objectives. In fact, we hold resource distribution constant, see if that was good enough, and adjust resource distribution if that didn't meet service level objectives. Here's an example of what happens today: Let's try 30% dedicated CPU. Not enough? Let's try 80% Oh, that's too much, and we're achieving much better response time than the objective, but other workloads are starving. Let's back that off and try again. It's not the process I object to - it's that we to often do this manually. Worse, we sometimes identify and adjust the wrong resource and fiddle with that to no useful result. Back in my days as a customer managing large systems, one of my users would call me up to beg for a "CPU boost": Me: "it won't make any difference - there's plenty of spare CPU to be had, and your application is completely I/O bound." User: "Please do it anyway." Me: "oh, all right, but it won't do you any good." (I did, because he was a friend, but it didn't help.) Prior art There are some operating environments that take a stab about workload management (rather than resource management) but I find them lacking. I know of one that uses synthetic "service units" composed of the sum of CPU, I/O and memory allocations multiplied by weighting factors. A workload is set to make a target rate of service units consumed per second. But this seems to be missing a key point: what is the relationship between artificial 'service units' and actually meeting a throughput or response time objective? What if I get plenty of one of the components (so am getting enough service units), but not enough of the resource whose needed to remove the bottleneck? Actual workload management That's not really the answer either. What is needed is to specify a workload's service levels in terms of externally visible metrics that are meaningful to a business, such as response times or transactions per second, and have the workload manager figure out which resources are not being adequately provided, and then adjust it as needed. If an application is not meeting its service level objectives and the reason is that it's not getting enough CPU cycles, adjust its CPU resource accordingly. If the reason is that the application isn't getting enough RAM to keep its working set in memory, then adjust its RAM assignment appropriately so it stops swapping. Simple idea, but that's a task we keep dumping on system administrators. In other words - don't hold the number of CPU shares constant and watch the achievement of service level vary. Instead, hold the service level constant, and dynamically adjust the number of CPU shares (or amount of other resources like RAM or I/O bandwidth) in order to meet the objective. Instrumenting non-instrumented applications There's one little problem here: how do I measure application performance in a way relating to a service level. I don't want to do it based on internal resources like number of CPU seconds it received per minute - We need to make resource decisions based on externally visible and meaningful measures of performance, not synthetic items or internal resource counters. If I have a way of marking the beginning and end of a transaction, I can then measure whether or not the application is meeting an objective based on it. If I can observe the delay factors for an application, I can see which resource shortages are slowing an application enough to keep it from meeting its objectives. I can then adjust resource allocations to relieve those shortages. Fortunately, Solaris provides facilities for both marking application progress and determining what factors cause application latency. The Solaris DTrace facility let's me introspect on application behavior: in particular I can see events like "receive a web hit" and "respond to that web hit" so I can get transaction rate and response time. DTrace (and tools like prstat) let me see where latency is being added to an application, so I know which resource to adjust. Summary After a delay of a mere few years, I am the proud creator of a patent (advice to anyone interested in going through the process: don't hold your breath!). The fundamental idea is fairly simple: instead of holding resource constant and suffering variable levels of success meeting service level objectives, properly characterise the service level objective in meaningful terms, instrument the application to see if it's meeting the objective, and then have a workload manager change resource allocations to remove delays preventing service level attainment. I've done it by hand for a long time - I think that's what a computer should do for me.

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• Impressions and Reactions from Alliance 2012

  - by user739873

  Alliance 2012 has come to a conclusion.  What strikes me about every Alliance conference is the amazing amount of collaboration and cooperation I see across higher education in the sharing of best practices around the entire Oracle PeopleSoft software suite, not just the student information system (Oracle’s PeopleSoft Campus Solutions).  In addition to the vibrant U.S. organization, it's gratifying to see the growth in the international attendance again this year, with an EMEA HEUG organizing to complement the existing groups in the Netherlands, South Africa, and the U.K.  Their first meeting is planned for London in October, and I suspect they'll be surprised at the amount of interest and attendance. In my discussions with higher education IT and functional leadership at Alliance there were a number of instances where concern was expressed about Oracle's commitment to higher education as an industry, primarily because of a lack of perceived innovation in the applications that Oracle develops for this market. Here I think perception and reality are far apart, and I'd like to explain why I believe this to be true. First let me start with what I think drives this perception. Predominately it's in two areas. The first area is the user interface, both for students and faculty that interact with the system as "customers", and for those employees of the institution (faculty, staff, and sometimes students as well) that use the system in some kind of administrative role. Because the UI hasn't changed all that much from the PeopleSoft days, individuals perceive this as a dead product with little innovation and therefore Oracle isn't investing. The second area is around the integration of the higher education suite of applications (PeopleSoft Campus Solutions) and the rest of the Oracle software assets. Whether grown organically or acquired, there is an impressive array of middleware and other software products that could be leveraged much more significantly by the higher education applications than is currently the case today. This is also perceived as lack of investment. Let me address these two points.  First the UI.  More is being done here than ever before, and the PAG and other groups where this was discussed at Alliance 2012 were more numerous than I've seen in any past meeting. Whether it's Oracle development leveraging web services or some extremely early but very promising work leveraging the recent Endeca acquisition (see some cool examples here) there are a lot of resources aimed at this issue.  There are also some amazing prototypes being developed by our UX (user experience team) that will eventually make their way into the higher education applications realm - they had an impressive setup at Alliance.  Hopefully many of you that attended found this group. If not, the senior leader for that team Jeremy Ashley will be a significant contributor of content to our summer Industry Strategy Council meeting in Washington in June. In the area of integration with other elements of the Oracle stack, this is also an area of focus for the company and my team.  We're making this a priority especially in the areas of identity management and security, leveraging WebCenter more effectively for content, imaging, and mobility, and driving towards the ultimate objective of WebLogic Suite as our platform for SOA, links to learning management systems (SAIP), and content. There is also much work around business intelligence centering on OBI applications. But at the end of the day we get enormous value from the HEUG (higher education user group) and the various subgroups formed as a part of this community that help us align and prioritize our investments, whether it's around better integration with other Oracle products or integration with partner offerings.  It's one of the healthiest, mutually beneficial relationships between customers and an Education IT concern that exists on the globe. And I can't avoid mentioning that this kind of relationship between higher education and the corporate IT community that can truly address the problems of efficiency and effectiveness, institutional excellence (which starts with IT) and student success.  It's not (in my opinion) going to be solved through community source - cost and complexity only increase in that model and in the end higher education doesn't ultimately focus on core competencies: educating, developing, and researching.  While I agree with some of what Michael A. McRobbie wrote in his EDUCAUSE Review article (Information Technology: A View from Both Sides of the President’s Desk), I take strong issue with his assertion that the "the IT marketplace is just the opposite of long-term stability...."  Sure there has been healthy, creative destruction in the past 2-3 decades, but this has had the effect of, in the aggregate, benefiting education with greater efficiency, more innovation and increased stability as larger, more financially secure firms acquire and develop integrated solutions. Cole

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• Adjusting server-side tickrate dynamically

  - by Stuart Blackler

  I know nothing of game development/this site, so I apologise if this is completely foobar. Today I experimented with building a small game loop for a network game (think MW3, CSGO etc). I was wondering why they do not build in automatic rate adjustment based on server performance? Would it affect the client that much if the client knew this frame is based on this tickrate? Has anyone attempted this before? Here is what my noobish C++ brain came up with earlier. It will improve the tickrate if it has been stable for x ticks. If it "lags", the tickrate will be reduced down by y amount: // GameEngine.cpp : Defines the entry point for the console application. // #ifdef WIN32 #include <Windows.h> #else #include <sys/time.h> #include <ctime> #endif #include<iostream> #include <dos.h> #include "stdafx.h" using namespace std; UINT64 GetTimeInMs() { #ifdef WIN32 /* Windows */ FILETIME ft; LARGE_INTEGER li; /* Get the amount of 100 nano seconds intervals elapsed since January 1, 1601 (UTC) and copy it * to a LARGE_INTEGER structure. */ GetSystemTimeAsFileTime(&ft); li.LowPart = ft.dwLowDateTime; li.HighPart = ft.dwHighDateTime; UINT64 ret = li.QuadPart; ret -= 116444736000000000LL; /* Convert from file time to UNIX epoch time. */ ret /= 10000; /* From 100 nano seconds (10^-7) to 1 millisecond (10^-3) intervals */ return ret; #else /* Linux */ struct timeval tv; gettimeofday(&tv, NULL); uint64 ret = tv.tv_usec; /* Convert from micro seconds (10^-6) to milliseconds (10^-3) */ ret /= 1000; /* Adds the seconds (10^0) after converting them to milliseconds (10^-3) */ ret += (tv.tv_sec * 1000); return ret; #endif } int _tmain(int argc, _TCHAR* argv[]) { int sv_tickrate_max = 1000; // The maximum amount of ticks per second int sv_tickrate_min = 100; // The minimum amount of ticks per second int sv_tickrate_adjust = 10; // How much to de/increment the tickrate by int sv_tickrate_stable_before_increment = 1000; // How many stable ticks before we increase the tickrate again int sys_tickrate_current = sv_tickrate_max; // Always start at the highest possible tickrate for the best performance int counter_stable_ticks = 0; // How many ticks we have not lagged for UINT64 __startTime = GetTimeInMs(); int ticks = 100000; while(ticks > 0) { int maxTimeInMs = 1000 / sys_tickrate_current; UINT64 _startTime = GetTimeInMs(); // Long code here... cout << "."; UINT64 _timeTaken = GetTimeInMs() - _startTime; if(_timeTaken < maxTimeInMs) { Sleep(maxTimeInMs - _timeTaken); counter_stable_ticks++; if(counter_stable_ticks >= sv_tickrate_stable_before_increment) { // reset the stable # ticks counter counter_stable_ticks = 0; // make sure that we don't go over the maximum tickrate if(sys_tickrate_current + sv_tickrate_adjust <= sv_tickrate_max) { sys_tickrate_current += sv_tickrate_adjust; // let me know in console #DEBUG cout << endl << "Improving tickrate. New tickrate: " << sys_tickrate_current << endl; } } } else if(_timeTaken > maxTimeInMs) { cout << endl; if((sys_tickrate_current - sv_tickrate_adjust) > sv_tickrate_min) { sys_tickrate_current -= sv_tickrate_adjust; } else { if(sys_tickrate_current == sv_tickrate_min) { cout << "Please reduce sv_tickrate_min..." << endl; } else{ sys_tickrate_current = sv_tickrate_min; } } // let me know in console #DEBUG cout << "The server has lag. Reduced tickrate to: " << sys_tickrate_current << endl; } ticks--; } UINT64 __timeTaken = GetTimeInMs() - __startTime; cout << endl << endl << "Total time in ms: " << __timeTaken; cout << endl << "Ending tickrate: " << sys_tickrate_current; char test; cin >> test; return 0; }

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• Hiring New IT Employees versus Promoting Internally for IT Positions

  Recently I was asked my opinion regarding the hiring of IT professionals in regards to the option of hiring new IT employees versus promoting internally for IT positions. After thinking a little more about this question regarding staffing, specifically pertaining to promoting internally verses new employees; I think my answer to this question is that it truly depends on the situation. However, in most cases I would side with promoting internally. The key factors in this decision should be based on a company/department’s current values, culture, attitude, and existing priorities.  For example if a company values retaining all of its hard earned business knowledge then they would tend to promote existing employees internal over hiring a new employee. Moreover, the company will have to pay to train an existing employee to learn a new technology and the learning curve for some technologies can be very steep. Conversely, if a company values new technologies and technical proficiency over business knowledge then a company would tend to hire new employees because they may already have experience with a technology that the company is planning on using. In this scenario, the company would have to take on the additional overhead of allowing a new employee to learn how the business operates prior to them being fully effective. To illustrate my points above let us look at contractor that builds in ground pools for example.  He has the option to hire employees that are very strong but use small shovels to dig, or employees weak in physical strength but use large shovels to dig. Which employee should the contractor use to dig a hole for a new in ground pool? If we compare the possible candidates for this job we will find that they are very similar to hiring someone internally verses a new hire. The first example represents the existing workers that are very strong regarding the understanding how the business operates and the reasons why in a specific manner. However this employee could be potentially weaker than an outsider pertaining to specific technologies and would need some time to build their technical prowess for a new position much like the strong worker upgrading their shovels in order to remove more dirt at once when digging. The other employee is very similar to hiring a new person that may already have the large shovel but will need to increase their strength in order to use the shovel properly and efficiently so that they can move a maximum amount of dirt in a minimal amount of time. This can be compared to new employ learning how a business operates before they can be fully functional and integrated in the company/department. Another key factor in this dilemma pertains to existing employee and their passion for their work, their ability to accept new responsibility when given, and the willingness to take on responsibilities when they see a need in the business. As much as possible should be considered in this decision down to the mood of the team, the quality of existing staff, learning cure for both technology and business, and the potential side effects of the existing staff.  In addition, there are many more consideration based on the current team/department/companies culture and mood. There are several factors that need to be considered when promoting an individual or hiring new blood for a team. They both can provide great benefits as well as create controversy to a group. Personally, staffing especially in the IT world is like building a large scale system in that all of the components and modules must fit together and preform as one cohesive system in the same way a team must come together using their individually acquired skills so that they can work as one team.  If a module is out of place or is nonexistent then the rest of the team will suffer until the all of its issues are addressed and resolved. Benefits of Promoting Internally Internal promotions give employees a reason to constantly upgrade their technology, business, and communication skills if they want to further their career Employees can control their own destiny based on personal desires Employee already knows how the business operates Companies can save money by promoting internally because the initial overhead of allowing new hires to learn how a company operates is very expensive Newly promoted employees can assist in training their replacements while transitioning to their new role within a company. Existing employees already have a proven track record in regards fitting in with the business culture; this is always an unknown with all new hires Benefits of a New Hire New employees can energize and excite existing employees New employees can bring new ideas and advancements in technology New employees can offer a different perspective on existing issues based on their past experience. As you can see the decision to promote an existing employee from within a company verses hiring a new person should be based on several factors that should ultimately place the business in the best possible situation for the immediate and long term future. How would you handle this situation? Would you hire a new employee or promote from within?

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• Revisiting the Generations

  - by Row Henson

  I was asked earlier this year to contribute an article to the IHRIM publication – Workforce Solutions Review.  My topic focused on the reality of the Gen Y population 10 years after their entry into the workforce.  Below is an excerpt from that article: It seems like yesterday that we were all talking about the entry of the Gen Y'ers into the workforce and what a radical change that would have on how we attract, retain, motivate, reward, and engage this new, younger segment of the workforce.  We all heard and read that these youngsters would be more entrepreneurial than their predecessors – the Gen X'ers – who were said to be more loyal to their profession than their employer. And, we heard that these “youngsters” would certainly be far less loyal to their employers than the Baby Boomers or even earlier Traditionalists. It was also predicted that – at least for the developed parts of the world – they would be more interested in work/life balance than financial reward; they would need constant and immediate reinforcement and recognition and we would be lucky to have them in our employment for two to three years. And, to keep them longer than that we would need to promote them often so they would be continuously learning since their long-term (10-year) goal would be to own their own business or be an independent consultant.  Well, it occurred to me recently that the first of the Gen Y'ers are now in their early 30s and it is time to look back on some of these predictions. Many really believed the Gen Y'ers would enter the workforce with an attitude – expect everything to be easy for them – have their employers meet their demands or move to the next employer, and I believe that we can now say that, generally, has not been the case. Speaking from personal experience, I have mentored a number of Gen Y'ers and initially felt that with a 40-year career in Human Resources and Human Resources Technology – I could share a lot with them. I found out very quickly that I was learning at least as much from them! Some of the amazing attributes I found from these under-30s was their fearlessness, ease of which they were able to multi-task, amazing energy and great technical savvy. They were very comfortable with collaborating with colleagues from both inside the company and peers outside their organization to problem-solve quickly. Most were eager to learn and willing to work hard.  This brings me to the generation that will follow the Gen Y'ers – the Generation Z'ers – those born after 1998. We have come full circle. If we look at the Silent Generation or Traditionalists, we find a workforce that preceded the television and even very early telephones. We Baby Boomers (as I fall right squarely in this category) remembered the invention of the television and telephone – but laptop computers and personal digital assistants (PDAs) were a thing of “StarTrek” and other science fiction movies and publications. Certainly, the Gen X'ers and Gen Y'ers grew up with the comfort of these devices just as we did with calculators. But, what of those under the age of 10 – how will the workplace look in 15 more years and what type of workforce will be required to operate in the mobile, global, virtual world. I spoke to a friend recently who had her four-year-old granddaughter for a visit. She said she found her in the den in front of the TV trying to use her hand to get the screen to move! So, you see – we have come full circle. The under-70 Traditionalist grew up in a world without TV and the Generation Z'er may never remember the TV we knew just a few years ago. As with every generation – we spend much time generalizing on their characteristics. The most important thing to remember is every generation – just like every individual – is different. The important thing for those of us in Human Resources to remember is that one size doesn’t fit all. What motivates one employee to come to work for you and stay there and be productive is very different than what the next employee is looking for and the organization that can provide this fluidity and flexibility will be the survivor for generations to come. And, finally, just when we think we have it figured out, a multitude of external factors such as the economy, world politics, industries, and technologies we haven’t even thought about will come along and change those predictions. As I reach retirement age – I do so believing that our organizations are in good hands with the generations to follow – energetic, collaborative and capable of working hard while still understanding the need for balance at work, at home and in the community! 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• How You Helped Shape Java EE 7...

  - by reza_rahman

  I have been working with the JCP in various roles since EJB 3/Java EE 5 (much of it on my own time), eventually culminating in my decision to accept my current role at Oracle (despite it's inevitable set of unique challenges, a role I find by and large positive and fulfilling). During these years, it has always been clear to me that pretty much everyone in the JCP genuinely cares about openness, feedback and developer participation. Perhaps the most visible sign to date of this high regard for grassroots level input is a survey on Java EE 7 gathered a few months ago. The survey was designed to get open feedback on a number of critical issues central to the Java EE 7 umbrella specification including what APIs to include in the standard. When we started the survey, I don't think anyone was certain what the level of participation from developers would really be. I also think everyone was pleasantly surprised that a large number of developers (around 1100) took the time out to vote on these very important issues that could impact their own professional life. And it wasn't just a matter of the quantity of responses. I was particularly impressed with the quality of the comments made through the survey (some of which I'll try to do justice to below). With Java EE 7 under our belt and the horizons for Java EE 8 emerging, this is a good time to thank everyone that took the survey once again for their thoughts and let you know what the impact of your voice actually was. As an aside, you may be happy to know that we are working hard behind the scenes to try to put together a similar survey to help kick off the agenda for Java EE 8 (although this is by no means certain). I'll break things down by the questions asked in the survey, the responses and the resulting change in the specification. APIs to Add to Java EE 7 Full/Web Profile The first question in the survey asked which of four new candidate APIs (WebSocket, JSON-P, JBatch and JCache) should be added to the Java EE 7 Full and Web profile respectively. Developers by and large wanted all the new APIs added to the full platform. The comments expressed particularly strong support for WebSocket and JCache. Others expressed dissatisfaction over the lack of a JSON binding (as opposed to JSON processing) API. WebSocket, JSON-P and JBatch are now part of Java EE 7. In addition, the long-awaited Java EE Concurrency Utilities API was also included in the Full Profile. Unfortunately, JCache was not finalized in time for Java EE 7 and the decision was made not to hold up the Java EE release any longer. JCache continues to move forward strongly and will very likely be included in Java EE 8 (it will be available much sooner than Java EE 8 to boot). An emergent standard for JSON-B is also a strong possibility for Java EE 8. When it came to the Web Profile, developers were supportive of adding WebSocket and JSON-P, but not JBatch and JCache. Both WebSocket and JSON-P are now part of the Web Profile, now also including the already popular JAX-RS API. Enabling CDI by Default The second question asked whether CDI should be enabled in Java EE by default. The overwhelming majority of developers supported the default enablement of CDI. In addition, developers expressed a desire for better CDI/Java EE alignment (with regards to EJB and JSF in particular). Some developers expressed legitimate concerns over the performance implications of enabling CDI globally as well as the potential conflict with other JSR 330 implementations like Spring and Guice. CDI is enabled by default in Java EE 7. Respecting the legitimate concerns, CDI 1.1 was very careful to add additional controls around component scanning. While a lot of work was done in Java EE 6 and Java EE 7 around CDI alignment, further alignment is under serious consideration for Java EE 8. Consistent Usage of @Inject The third question was around using CDI/JSR 330 @Inject consistently vs. allowing JSRs to create their own injection annotations (e.g. @BatchContext). A majority of developers wanted consistent usage of @Inject. The comments again reflected a strong desire for CDI/Java EE alignment. A lot of emphasis in Java EE 7 was put into using @Inject consistently. For example, the JBatch specification is focused on using @Inject wherever possible. JAX-RS remains an exception with it's existing custom injection annotations. However, the JAX-RS specification leads understand the importance of eventual convergence, hopefully in Java EE 8. Expanding the Use of @Stereotype The fourth question was about expanding CDI @Stereotype to cover annotations across Java EE beyond just CDI. A solid majority of developers supported the idea of making @Stereotype more universal in Java EE. The comments maintained the general theme of strong support for CDI/Java EE alignment Unfortunately, there was not enough time and resources in Java EE 7 to implement this fairly pervasive feature. However, it remains a serious consideration for Java EE 8. Expanding Interceptor Use The final set of questions was about expanding interceptors further across Java EE. Developers strongly supported the concept. Along with injection, interceptors are now supported across all Java EE 7 components including Servlets, Filters, Listeners, JAX-WS endpoints, JAX-RS resources, WebSocket endpoints and so on. I hope you are encouraged by how your input to the survey helped shape Java EE 7 and continues to shape Java EE 8. Participating in these sorts of surveys is of course just one way of contributing to Java EE. Another great way to stay involved is the Adopt-A-JSR Program. A large number of developers are already participating through their local JUGs. You could of course become a Java EE JSR expert group member or observer. You should stay tuned to The Aquarium for the progress of Java EE 8 JSRs if that's something you want to look into...

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• Vendors: Partners or Salespeople?

  - by BuckWoody

  I got a great e-mail from a friend that asked about how he could foster a better relationship with his vendors. So many times when you work with a vendor it’s more of a used-car sales experience than a partnership – but you can actually make your vendor more of a partner, as long as you both set some ground-rules at the start. Sit down with your vendor, and have a heart-to-heart talk with them, explain that they won’t win every time, but that you’re willing to work with them in an honest way on both sides. Here’s the advice I sent him verbatim. I hope this post generates lots of comments from both customers and vendors. I don’t expect that you’ve had a great experience with your Microsoft reps, but I happen to work with some of the best sales teams in the business, and our clients tell us that all the time. “The key to this relationship is to keep the audience really small. Ideally there should be one person from your side that is responsible for the relationship, and one from the vendor’s side. Each responsible person should have the authority to make decisions, and to bring in other folks as needed for a given topic, project or decision.   For Microsoft, this is called an “Account Manager” – they aren’t technical, they aren’t sales. They “own” a relationship with a company. They learn what the company does, who does it, and how. They are responsible to understand what the challenges in your company are. While they don’t know the bits and bytes of everything we sell, they know what each thing does, and who to talk to about it. I get a call from an Account Manager every week that has pre-digested an issue at an organization and says to me: “I need you to set up an architectural meeting with their technical staff to get a better read on how we can help with problem X.” I do that and then report back to the Account Manager what we learned.  All through this process there’s the atmosphere of a “team”, not a “sales opportunity” per se. I’ve even recommended that the firm use a rival product, and I’ve never gotten push-back on that decision from my Account Managers.   But that brings up an interesting point. Someone pays an Account Manager and pays me. They expect something in return. At some point, you have to buy something. Not every time, not every situation – sometimes it’s just helping you with what you already bought from us. But the point is that you can’t expect lots of love and never spend any money. That’s the way business works.   Finally, don’t view the vendor as someone with their hand in your pocket – somebody that’s just trying to sell you something and doesn’t care if they ever see you again – unless they deserve it. There are plenty of “love them and leave them” companies out there, and you may have even had this experience with us, but that isn’t the case in the firms I work with. In fact, my customers get a questionnaire that asks them that exact question. “How many times have you seen your account team? Did you like your interaction with them? Can they do better?” My raises, performance reviews and general standing in my group are based on the answers the company gives.  Ask your vendor if they measure their sales and support teams this way – if not, seek another vendor to partner with.   Partnering with someone is a big deal. It involves time and effort on your part, and on the vendor’s part. If either of you isn’t pulling your weight, it just won’t work. You have every right to expect them to treat you as a partner, and they have the same right for your side.” Share this post: email it! | bookmark it! | digg it! | reddit! | kick it! | live it!

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• "Guiding" a Domain Expert to Retire from Programming

  - by James Kolpack

  I've got a friend who does IT at a local non-profit where they're using a custom web application which is no longer supported by the company who built it. (out of business, support was too expensive, I'm not sure...) Development on this app started around 10+ years ago so the technologies being harnessed are pretty out of date now - classic asp using vbscript and SQL Server 2000. The application domain is in the realm of government bookkeeping - so even though the development team is long gone, there are often new requirements of this software. Enter the... The domain expert. This is an middle aged accounting whiz without much (or any?) prior development experience. He studied the pages, code and queries and learned how to ape the style of the original team which, believe me, is mediocre at best. He's very clever and very tenacious but has no experience in software beyond what he's picked up from this app. Otherwise, he's a pleasant guy to talk to and definitely knows his domain. My friend in IT, and probably his superiors in the company, want him out of the code. They view him as wasting his expertise on coding tasks he shouldn't be doing. My friend got me involved with a few small contracts which I handled without much problem - other than somewhat of a communication barrier with the domain expert. He explained the requirements very quickly, assuming prior knowledge of the domain which I do not have. This is partially his normal style, and I think maybe a bit of resentment from my involvement. So, I think he feels like the owner of the code and has entrenched himself in a development position. So... his coding technique. One of his latest endeavors was to make a page that only he could reach (theoretically - the security model for the system is wretched) where he can enter a raw SQL query, run it, and save the query to run again later. A report that I worked on had been originally implemented by him using 6 distinct queries, 3 or 4 temp tables to coordinate the data between the queries, and the final result obtained by importing the data from the final query into Access and doing a pivot and some formatting. It worked - well, some of the results were incorrect - but at what a cost! (I implemented the report in a single query with at least 1/10th the amount of code.) He edits code in notepad. He doesn't seem to know about online reference material for the languages. I recently read an article on Dr. Dobbs titled "What Makes Bad Programmers Different" - and instantly thought of our domain expert. From the article: Their code is large, messy, and bug laden. They have very superficial knowledge of their problem domain and their tools. Their code has a lot of copy/paste and they have very little interest in techniques that reduce it. The fail to account for edge cases, while inefficiently dealing with the general case. They never have time to comment their code or break it into smaller pieces. Empirical evidence plays no little role in their decisions. 5.5 out of 6. My friend is wanting me to argue the case to their management - specifically, I got this email from their manager to respond to: ...Also, I need to talk to you about what effect there is from Domain Expert continuing to make edits to the live environment. If that is a problem for you I need to know so I can have his access blocked. Some examples would help. In my opinion, from a technical standpoint, it's dangerous to have him making changes without any oversight. On the other hand, I'm just doing one-off contracts at this point and don't have much desire to get involved deeply enough that I'm essentially arguing as one of the Bobs from Office Space. I'd like to help my friend out - but I feel like I'm getting in the middle of a political battle. More importantly - if I do get involved and suggest that his editing privileges be removed, it needs to be handled carefully so that doesn't feel belittled. He is beyond a doubt the foremost expert on this system. I'm hoping this is familiar territory for some other stackechangers, because I'm feeling a little bewildered. How should I respond? Should I argue that he shouldn't be allowed to touch the code? Should I phrase it as "no single developer, no matter how experienced, should be working on production code unchecked"? Should I argue to keep him involved with the code, but with a review process? Should I say "glad I could help, but uh, I'm busy now!" Other options? Thanks a bunch!

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• Contricted A* problem

  - by Ragekit

  I've got a little problem with an A* algorithm that I need to constrict a little bit. Basically : I use an A* to find the shortest path between 2 randomly placed room in 3D space, and then build a corridor between them. The problem I found is that sometimes it makes chimney like corridors that are not ideal, so I constrict the A* so that if the last movement was up or down, you go sideways. Everything is fine, but in some corner cases, it fails to find a path (when there is obviously one). Like here between the blue and red dot : (i'm in unity btw, but i don't think it matters) Here is the code of the actual A* (a bit long, and some redundency) while(current != goal) { //add stair up / stair down foreach(Node<GridUnit> test in current.Neighbors) { if(!test.Data.empty && test != goal) continue; //bug at arrival; if(test == goal && penul !=null) { Vector3 currentDiff = current.Data.bounds.center - test.Data.bounds.center; if(!Mathf.Approximately(currentDiff.y,0)) { //wanna drop on the last if(!coplanar(test.Data.bounds.center,current.Data.bounds.center,current.Data.parentUnit.bounds.center,to.Data.bounds.center)) { continue; } else { if(Mathf.Approximately(to.Data.bounds.center.x, current.Data.parentUnit.bounds.center.x) && Mathf.Approximately(to.Data.bounds.center.z, current.Data.parentUnit.bounds.center.z)) { continue; } } } } if(current.Data.parentUnit != null) { Vector3 previousDiff = current.Data.parentUnit.bounds.center - current.Data.bounds.center; Vector3 currentDiff = current.Data.bounds.center - test.Data.bounds.center; if(!Mathf.Approximately(previousDiff.y,0)) { if(!Mathf.Approximately(currentDiff.y,0)) { //you wanna drop now : continue; } if(current.Data.parentUnit.parentUnit != null) { if(!coplanar(test.Data.bounds.center,current.Data.bounds.center,current.Data.parentUnit.bounds.center,current.Data.parentUnit.parentUnit.bounds.center)) { continue; }else { if(Mathf.Approximately(test.Data.bounds.center.x, current.Data.parentUnit.parentUnit.bounds.center.x) && Mathf.Approximately(test.Data.bounds.center.z, current.Data.parentUnit.parentUnit.bounds.center.z)) { continue; } } } } } g = current.Data.g + HEURISTIC(current.Data,test.Data); h = HEURISTIC(test.Data,goal.Data); f = g + h; if(open.Contains(test) || closed.Contains(test)) { if(test.Data.f > f) { //found a shorter path going passing through that point test.Data.f = f; test.Data.g = g; test.Data.h = h; test.Data.parentUnit = current.Data; } } else { //jamais rencontré test.Data.f = f; test.Data.h = h; test.Data.g = g; test.Data.parentUnit = current.Data; open.Add(test); } } closed.Add (current); if(open.Count == 0) { Debug.Log("nothingfound"); //nothing more to test no path found, stay to from; List<GridUnit> r = new List<GridUnit>(); r.Add(from.Data); return r; } //sort open from small to biggest travel cost open.Sort(delegate(Node<GridUnit> x, Node<GridUnit> y) { return (int)(x.Data.f-y.Data.f); }); //get the smallest travel cost node; Node<GridUnit> smallest = open[0]; current = smallest; open.RemoveAt(0); } //build the path going backward; List<GridUnit> ret = new List<GridUnit>(); if(penul != null) { ret.Insert(0,to.Data); } GridUnit cur = goal.Data; ret.Insert(0,cur); do{ cur = cur.parentUnit; ret.Insert(0,cur); } while(cur != from.Data); return ret; You see at the start of the foreach i constrict the A* like i said. If you have any insight it would be cool. Thanks

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• How to make creating viewmodels at runtime less painfull

  - by Mr Happy

  I apologize for the long question, it reads a bit as a rant, but I promise it's not! I've summarized my question(s) below In the MVC world, things are straightforward. The Model has state, the View shows the Model, and the Controller does stuff to/with the Model (basically), a controller has no state. To do stuff the Controller has some dependencies on web services, repository, the lot. When you instantiate a controller you care about supplying those dependencies, nothing else. When you execute an action (method on Controller), you use those dependencies to retrieve or update the Model or calling some other domain service. If there's any context, say like some user wants to see the details of a particular item, you pass the Id of that item as parameter to the Action. Nowhere in the Controller is there any reference to any state. So far so good. Enter MVVM. I love WPF, I love data binding. I love frameworks that make data binding to ViewModels even easier (using Caliburn Micro a.t.m.). I feel things are less straightforward in this world though. Let's do the exercise again: the Model has state, the View shows the ViewModel, and the ViewModel does stuff to/with the Model (basically), a ViewModel does have state! (to clarify; maybe it delegates all the properties to one or more Models, but that means it must have a reference to the model one way or another, which is state in itself) To do stuff the ViewModel has some dependencies on web services, repository, the lot. When you instantiate a ViewModel you care about supplying those dependencies, but also the state. And this, ladies and gentlemen, annoys me to no end. Whenever you need to instantiate a ProductDetailsViewModel from the ProductSearchViewModel (from which you called the ProductSearchWebService which in turn returned IEnumerable<ProductDTO>, everybody still with me?), you can do one of these things: call new ProductDetailsViewModel(productDTO, _shoppingCartWebService /* dependcy */);, this is bad, imagine 3 more dependencies, this means the ProductSearchViewModel needs to take on those dependencies as well. Also changing the constructor is painfull. call _myInjectedProductDetailsViewModelFactory.Create().Initialize(productDTO);, the factory is just a Func, they are easily generated by most IoC frameworks. I think this is bad because Init methods are a leaky abstraction. You also can't use the readonly keyword for fields that are set in the Init method. I'm sure there are a few more reasons. call _myInjectedProductDetailsViewModelAbstractFactory.Create(productDTO); So... this is the pattern (abstract factory) that is usually recommended for this type of problem. I though it was genious since it satisfies my craving for static typing, until I actually started using it. The amount of boilerplate code is I think too much (you know, apart from the ridiculous variable names I get use). For each ViewModel that needs runtime parameters you'll get two extra files (factory interface and implementation), and you need to type the non-runtime dependencies like 4 extra times. And each time the dependencies change, you get to change it in the factory as well. It feels like I don't even use an DI container anymore. (I think Castle Windsor has some kind of solution for this [with it's own drawbacks, correct me if I'm wrong]). do something with anonymous types or dictionary. I like my static typing. So, yeah. Mixing state and behavior in this way creates a problem which don't exist at all in MVC. And I feel like there currently isn't a really adequate solution for this problem. Now I'd like to observe some things: People actually use MVVM. So they either don't care about all of the above, or they have some brilliant other solution. I haven't found an indepth example of MVVM with WPF. For example, the NDDD-sample project immensely helped me understand some DDD concepts. I'd really like it if someone could point me in the direction of something similar for MVVM/WPF. Maybe I'm doing MVVM all wrong and I should turn my design upside down. Maybe I shouldn't have this problem at all. Well I know other people have asked the same question so I think I'm not the only one. To summarize Am I correct to conclude that having the ViewModel being an integration point for both state and behavior is the reason for some difficulties with the MVVM pattern as a whole? Is using the abstract factory pattern the only/best way to instantiate a ViewModel in a statically typed way? Is there something like an in depth reference implementation available? Is having a lot of ViewModels with both state/behavior a design smell?

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• Avoiding coupling

  - by Seralize

  It is also true that a system may become so coupled, where each class is dependent on other classes that depend on other classes, that it is no longer possible to make a change in one place without having a ripple effect and having to make subsequent changes in many places.[1] This is why using an interface or an abstract class can be valuable in any object-oriented software project. Quote from Wikipedia Starting from scratch I'm starting from scratch with a project that I recently finished because I found the code to be too tightly coupled and hard to refactor, even when using MVC. I will be using MVC on my new project aswell but want to try and avoid the pitfalls this time, hopefully with your help. Project summary My issue is that I really wish to keep the Controller as clean as possible, but it seems like I can't do this. The basic idea of the program is that the user picks wordlists which is sent to the game engine. It will pick random words from the lists until there are none left. Problem at hand My main problem is that the game will have 'modes', and need to check the input in different ways through a method called checkWord(), but exactly where to put this and how to abstract it properly is a challenge to me. I'm new to design patterns, so not sure whether there exist any might fit my problem. My own attempt at abstraction Here is what I've gotten so far after hours of 'refactoring' the design plans, and I know it's long, but it's the best I could do to try and give you an overview (Note: As this is the sketch, anything is subject to change, all help and advice is very welcome. Also note the marked coupling points): Wordlist class Wordlist { // Basic CRUD etc. here! // Other sample methods: public function wordlistCount($user_id) {} // Returns count of how many wordlists a user has public function getAll($user_id) {} // Returns all wordlists of a user } Word class Word { // Basic CRUD etc. here! // Other sample methods: public function wordCount($wordlist_id) {} // Returns count of words in a wordlist public function getAll($wordlist_id) {} // Returns all words from a wordlist public function getWordInfo($word_id) {} // Returns information about a word } Wordpicker class Wordpicker { // The class needs to know which words and wordlists to exclude protected $_used_words = array(); protected $_used_wordlists = array(); // Wordlists to pick words from protected $_wordlists = array(); /* Public Methods */ public function setWordlists($wordlists = array()) {} public function setUsedWords($used_words = array()) {} public function setUsedWordlists($used_wordlists = array()) {} public function getRandomWord() {} // COUPLING POINT! Will most likely need to communicate with both the Wordlist and Word classes /* Protected Methods */ protected function _checkAvailableWordlists() {} // COUPLING POINT! Might need to check if wordlists are deleted etc. protected function _checkAvailableWords() {} // COUPLING POINT! Method needs to get all words in a wordlist from the Word class } Game class Game { protected $_session_id; // The ID of a game session which gets stored in the database along with game details protected $_game_info = array(); // Game instantiation public function __construct($user_id) { if (! $this->_session_id = $this->_gameExists($user_id)) { // New game } else { // Resume game } } // This is the method I tried to make flexible by using abstract classes etc. // Does it even belong in this class at all? public function checkWord($answer, $native_word, $translation) {} // This method checks the answer against the native word / translation word, depending on game mode public function getGameInfo() {} // Returns information about a game session, or creates it if it does not exist public function deleteSession($session_id) {} // Deletes a game session from the database // Methods dealing with game session information protected function _gameExists($user_id) {} protected function _getProgress($session_id) {} protected function _updateProgress($game_info = array()) {} } The Game /* CONTROLLER */ /* "Guess the word" page */ // User input $game_type = $_POST['game_type']; // Chosen with radio buttons etc. $wordlists = $_POST['wordlists']; // Chosen with checkboxes etc. // Starts a new game or resumes one from the database $game = new Game($_SESSION['user_id']); $game_info = $game->getGameInfo(); // Instantiates a new Wordpicker $wordpicker = new Wordpicker(); $wordpicker->setWordlists((isset($game_info['wordlists'])) ? $game_info['wordlists'] : $wordlists); $wordpicker->setUsedWordlists((isset($game_info['used_wordlists'])) ? $game_info['used_wordlists'] : NULL); $wordpicker->setUsedWords((isset($game_info['used_words'])) ? $game_info['used_words'] : NULL); // Fetches an available word if (! $word_id = $wordpicker->getRandomWord()) { // No more words left - game over! $game->deleteSession($game_info['id']); redirect(); } else { // Presents word details to the user $word = new Word(); $word_info = $word->getWordInfo($word_id); } The Bit to Finish /* CONTROLLER */ /* "Check the answer" page */ // ?????????????????? ( http://pastebin.com/cc6MtLTR ) Make sure you toggle the 'Layout Width' to the right for a better view. Thanks in advance. Questions To which extent should objects be loosely coupled? If object A needs info from object B, how is it supposed to get this without losing too much cohesion? As suggested in the comments, models should hold all business logic. However, as objects should be independent, where to glue them together? Should the model contain some sort of "index" or "client" area which connects the dots? Edit: So basically what I should do for a start is to make a new model which I can more easily call with oneliners such as $model->doAction(); // Lots of code in here which uses classes! How about the method for checking words? Should it be it's own object? I'm not sure where I should put it as it's pretty much part of the 'game'. But on another hand, I could just leave out the 'abstraction and OOPness' and make it a method of the 'client model' which will be encapsulated from the controller anyway. Very unsure about this.

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• Tip #19 Module Private Visibility in OSGi

  - by ByronNevins

  I hate public and protected methods and classes.  It requires so much work to change them in a huge project like GlassFish.  Not to mention that you may well have to support those APIs forever.  They are highly overused in GlassFish.  In fact I'd bet that > 95% of classes are marked as public for no good reason.  It's just (bad) habit is my guess. private and default visibility (I call it package-private) is easier to maintain.  It is much much easier to change such classes and methods around.  If you have ANY public method or public class in GlassFish you'll need to grep through a tremendous amount of source code to find all callers.  But even that won't be theoretically reliable.  What if a caller is using reflection to access public methods?  You may never find such usages. If you have package private methods, it's easy.  Simply grep through all the code in that one package.  As long as that package compiles ok you're all set.  There can' be any compile errors anywhere else.  It's a waste of time to even look around or build the "outside" world.  So you may be thinking: "Aha!  I'll just make my module have one giant package with all the java files.  Then I can use the default visibility and maintenance will be much easier.  But there's a problem.  You are wasting a very nice feature of java -- organizing code into separate packages.  It also makes the code much more encapsulated.  Unfortunately to share code between the packages you have no choice but to declare public visibility. What happens in practice is that a module ends up having tons of public classes and methods that are used exclusively inside the module.  Which finally brings me to the point of this blog:  If Only There Was A Module-Private Visibility Available Well, surprise!  There is such a mechanism.  If your project is running under OSGi that is.  Like GlassFish does!  With this mechanism you can easily add another level of visibility by telling OSGi exactly which public you want to be exposed outside of the module.  You get the best of both worlds: Better encapsulation of your code so that maintenance is easier and productivity is increased. Usage of public visibility inside the module so that you can encapsulate intra-module better with packages. How I do this in GlassFish: Carefully plan out at least one package that will contain "true" publics.  This is the package that will be exported by OSGi.  I recommend just one package. Here is how to tell OSGi to use it in GlassFish -- edit osgi.bundle like so:-exportcontents:     org.glassfish.mymodule.truepublics;  version=${project.osgi.version} Now all publics declared in any other packages will be visible module-wide but not outside the module. There is one caveat: Accessing "module-private" items outside of the module is controlled at run-time, not compile-time.  The compiler has no clue that a public in a dependent module isn't really public.  it will happily compile it.  At runtime you will definitely see fireworks.  The good news is that you don't have to wait for the code path that tries to use the "module-private" items to fire.  OSGi will complain loudly when that module gets loaded.  OSGi will refuse to load it.  You will see an error like this: remote failure: Error while loading FOO: Exception while adding the new configuration : Error occurred during deployment: Exception while loading the app : org.osgi.framework.BundleException: Unresolved constraint in bundle com.oracle.glassfish.miscreant.code [115]: Unable to resolve 115.0: missing requirement [115.0] osgi.wiring.package; (osgi.wiring.package=org.glassfish.mymodule.unexported). Please see server.log for more details. That is if you accidentally change code in module B to use a public that is really a "module-private" in module A, then you will see the error immediately when you try to test whatever you were changing in module B.

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• CS, SE, HCI, Information Science, Please recommendation for further education of the former performing art manager seeking career in IT industries? [on hold]

  - by Baek Seungjoo

  IT specialists there J Thank you very much for your collective efforts here, and I got huge help reading your professional comments and advices on each questions I have searched so far! This time, I would like to ask for your practical advices or recommendation on what I am struggling on at this moment. I am currently seeking higher education for my career transition from performing art manager and director to “IT software and/or service development and management specialist”. However, as this field is quite new to me, and there are lots of different work positions, I have no idea which grad major I better pursue in order to get qualification. Of course I know this question could sounds wired as it is kind of personal choice. But my lack of understanding on how IT software companies work in general, your practical and experience-based advice will be great help to me, who spent more than two months of self-research on net. OK. Before my question, here is my plan and history, which are quite different from those currently in IT industry I think… 1) Target Firstly, get career transition into IT service or products companies and get experiences. Eventually, pursue IT entrepreneurship in combination with my arts and cultural production and business expertise. 2) Background Career: performing arts director and manager in theatre-based scale opera and musical Art education in youth BA in literature and Chinese studies (Art & Humanities) MA in Cultural & Creative Industries (Art & Humanities) – dissertation with focus on digital prosumption and the lived experience of the prosumer. (a qualitative research on the agents in the digital world) 2) Personally Huge interest in IT hardware and software, and their trend. Skills to build up, repair, tune PCs -of course this is no more than personal hobby, but shows my interests in this field. 4) Problem Encounter a question “So, what do you think you can contribute practically in this position”. This question turn me down everytime I go through job interviews, and I decided more education in the relevant area. Here are my questions. 1) In terms of work positions in IT software companies, I wonder if I can put the comparison of what “Artists” is to “Arts Manager or Director” is what “Developer” is to “Product Manager”. (Of course, this stereotypical division of Artist-Art Manager is out of sense because the domain overlaps to some extent, and is blurring at least in my field, and they are in different contexts, but just speaking easily.) Normally, artist comes with special arts educations, and they live in their own world of artistic inspiration and creation, and they feel alive in practice and on stages. Meanwhile, from the point of staging and managing productions, the role of art manager is critical as well. Our role cares how the production appeals to the audience in effective way, how to make profit and future sustainable management through that, how to set up future strategy in consideration of the external conditions such as political and social circumstances, audience trend and level, other production trends from on-going and historical perspectives, how and what the production make voice to the society from political, economic, humanitarian stances. So, we need keen eyes on economic, political, and societal environment, have to understand human-being and their desires, must know how to make presentation and attract investors, must have sense in managing and fighting over the limited financial resource, how to extend networking and so on. It is common that the two agents create productions in collaboration (normally not in that ideal way but in conflict and fight though J ). So, we need to know each other’s expertise to some extent, for better production. What are the work positions in IT software industries equivalent to the role of “art manager” in performing arts? From my view, considering developers come with special education in the world of computer science, software engineering, or others (self-education sometimes), and they express themselves with the arts of coding, computer languages on the black screen, and make sort of their artistic production online to the audience, I guess there might be someone who collaborate with developers in creating, managing, and launching IT services or products. 2) Which education among CS, SE, HCI, Information Science, is needed for those seeking such work position? Especially for person like me. (At this moment, Information Science has the highest possibility to get in, since I lack Calculus and Math in undergrad educaiton. But please let me know irrespective of this concern, I think there are ways to back it up if CS or SE education needed in my case) 3) Which field between Information Science and HCI can be more practical background regarding job hungting? And which of them have more demands in job market? AS I checked, HCI is more close to CS than IS in its focus of study area. Thank you very much for your patience reading such a long inquiry, and I appreciate to your efforts in advance. Have a nice day in this beautiful summer.

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• Reading the tea leaves from Windows Azure support

  - by jamiet

  A few idle thoughts… Three months ago I had an issue regarding Windows Azure where I was unable to login to the management portal. At the time I contacted Azure support, the issue was soon resolved and I thought no more about it. Until today that is when I received an email from Azure support providing a detailed analysis of the root cause, the fix and moreover precise details about when and where things occurred. The email itself is interesting and I have included the entirety of it below. A few things were interesting to me: The level of detail and the diligence in investigating and reporting the issue I found really rather impressive. They even outline the number of users that were affected (127 in case you can’t be bothered reading). Compare this to the quite pathetic support that another division within Microsoft, Skype, provided to Greg Low recently: Skype support and dead parrot sketches   This line: “Windows Azure performed a planned change from using the Microsoft account service (formerly Windows Live ID) to the Azure Active Directory (AAD) as its primary authentication mechanism on August 24th. This change was made to enable future innovation in the area of authentication – particularly for organizationally owned identities, identity federation, stronger authentication methods and compliance certification. ” I also found to be particularly interesting. I have long thought that one of the reasons Microsoft has proved to be such a money-making machine in the enterprise is because they provide the infrastructure and then upsell on top of that – and nothing is more infrastructural than Active Directory. It has struck me of late that they are trying to make the same play of late in the cloud by tying all their services into Azure Active Directory and here we see a clear indication of that by making AAD the authentication mechanism for anyone using Windows Azure. I get the feeling that we’re going to hear much much more about AAD in the future; isn’t it about time we could log on to SQL Azure Windows Azure SQL Database without resorting to SQL authentication, for example? And why do Microsoft have two identity providers – Microsoft Account (aka Windows Live ID) and AAD – isn’t it about time those things were combined? As I said, just some idle thoughts. Below is the transcript of the email if you are interested. @Jamiet  This is regarding the support request <redacted> where in you were not able to login into the windows azure management portal with live id. We are providing you with the summary, root cause analysis and information about permanent fix: Incident Title: You were unable to access Windows Azure Portal after Microsoft Account to Azure Active Directory account Migration. Service Impacted: Management Portal Incident Start Date and Time: 8/24/2012 4:30:00 PM Date and Time Service was Restored: 10/17/2012 12:00:00 AM Summary: Windows Azure performed a planned change from using the Microsoft account service (formerly Windows Live ID) to the Azure Active Directory (AAD) as its primary authentication mechanism on August 24th.   This change was made to enable future innovation in the area of authentication – particularly for organizationally owned identities, identity federation, stronger authentication methods and compliance certification.   While this migration was largely transparent to Windows Azure users, a small number of users whose sign-in names were part of a Windows Live Custom Domain were unable to login.   This incompatibility was not discovered during the Quality Assurance testing phase prior to the migration. Customer Impact: Customers whose sign-in names were part of a Windows Live Custom Domain were unable to sign-in the Management Portal after ~4:00 p.m. PST on August 24th, 2012.   We determined that the issue did impact at least 127 users in 98 of these Windows Live Custom Domains and had a maximum potential impact of 1,110 users in total. Root Cause: The root cause of the issue was an incompatibility in the AAD authentication service to handle logins from Microsoft accounts whose sign-in names were part of a Windows Live Custom Domains.  This issue was not discovered during the Quality Assurance testing phase prior to the migration from Microsoft Account (MSA) to AAD. Mitigations: The issue was mitigated for the majority of affected users by 8:20 a.m. PST on August 25th, 2012 by running some internal scripts to correct many known Windows Live Custom Domains.   The remaining affected domains fell into two categories: Windows Live Custom Domains that were not corrected by 8/25/2012. An additional 48 Windows Live Custom Domains were fixed in the weeks following the incident within 2 business days after the AAD team received an escalation from product support regarding those accounts. Windows Live Custom domains that were also provisioned in Office365. Some of the affected Windows Live Custom Domains had already been provisioned in AAD because their owners signed up for Office365 which is a service that also uses AAD.   In these cases the Azure customers had to work around the issue by renaming their Microsoft Account or using a different Microsoft Account to administer their Azure subscription. Permanent Fix: The Azure Active Directory team permanently fixed the issue for all customers on 10/17/2012 in an upgraded release of the AAD service.

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• Developing Schema Compare for Oracle (Part 6): 9i Query Performance

  - by Simon Cooper

  All throughout the EAP and beta versions of Schema Compare for Oracle, our main request was support for Oracle 9i. After releasing version 1.0 with support for 10g and 11g, our next step was then to get version 1.1 of SCfO out with support for 9i. However, there were some significant problems that we had to overcome first. This post will concentrate on query execution time. When we first tested SCfO on a 9i server, after accounting for various changes to the data dictionary, we found that database registration was taking a long time. And I mean a looooooong time. The same database that on 10g or 11g would take a couple of minutes to register would be taking upwards of 30 mins on 9i. Obviously, this is not ideal, so a poke around the query execution plans was required. As an example, let's take the table population query - the one that reads ALL_TABLES and joins it with a few other dictionary views to get us back our list of tables. On 10g, this query takes 5.6 seconds. On 9i, it takes 89.47 seconds. The difference in execution plan is even more dramatic - here's the (edited) execution plan on 10g: -------------------------------------------------------------------------------| Id | Operation | Name | Bytes | Cost |-------------------------------------------------------------------------------| 0 | SELECT STATEMENT | | 108K| 939 || 1 | SORT ORDER BY | | 108K| 939 || 2 | NESTED LOOPS OUTER | | 108K| 938 ||* 3 | HASH JOIN RIGHT OUTER | | 103K| 762 || 4 | VIEW | ALL_EXTERNAL_LOCATIONS | 2058 | 3 ||* 20 | HASH JOIN RIGHT OUTER | | 73472 | 759 || 21 | VIEW | ALL_EXTERNAL_TABLES | 2097 | 3 ||* 34 | HASH JOIN RIGHT OUTER | | 39920 | 755 || 35 | VIEW | ALL_MVIEWS | 51 | 7 || 58 | NESTED LOOPS OUTER | | 39104 | 748 || 59 | VIEW | ALL_TABLES | 6704 | 668 || 89 | VIEW PUSHED PREDICATE | ALL_TAB_COMMENTS | 2025 | 5 || 106 | VIEW | ALL_PART_TABLES | 277 | 11 |------------------------------------------------------------------------------- And the same query on 9i: -------------------------------------------------------------------------------| Id | Operation | Name | Bytes | Cost |-------------------------------------------------------------------------------| 0 | SELECT STATEMENT | | 16P| 55G|| 1 | SORT ORDER BY | | 16P| 55G|| 2 | NESTED LOOPS OUTER | | 16P| 862M|| 3 | NESTED LOOPS OUTER | | 5251G| 992K|| 4 | NESTED LOOPS OUTER | | 4243M| 2578 || 5 | NESTED LOOPS OUTER | | 2669K| 1440 ||* 6 | HASH JOIN OUTER | | 398K| 302 || 7 | VIEW | ALL_TABLES | 342K| 276 || 29 | VIEW | ALL_MVIEWS | 51 | 20 ||* 50 | VIEW PUSHED PREDICATE | ALL_TAB_COMMENTS | 2043 | ||* 66 | VIEW PUSHED PREDICATE | ALL_EXTERNAL_TABLES | 1777K| ||* 80 | VIEW PUSHED PREDICATE | ALL_EXTERNAL_LOCATIONS | 1744K| ||* 96 | VIEW | ALL_PART_TABLES | 852K| |------------------------------------------------------------------------------- Have a look at the cost column. 10g's overall query cost is 939, and 9i is 55,000,000,000 (or more precisely, 55,496,472,769). It's also having to process far more data. What on earth could be causing this huge difference in query cost? After trawling through the '10g New Features' documentation, we found item 1.9.2.21. Before 10g, Oracle advised that you do not collect statistics on data dictionary objects. From 10g, it advised that you do collect statistics on the data dictionary; for our queries, Oracle therefore knows what sort of data is in the dictionary tables, and so can generate an efficient execution plan. On 9i, no statistics are present on the system tables, so Oracle has to use the Rule Based Optimizer, which turns most LEFT JOINs into nested loops. If we force 9i to use hash joins, like 10g, we get a much better plan: -------------------------------------------------------------------------------| Id | Operation | Name | Bytes | Cost |-------------------------------------------------------------------------------| 0 | SELECT STATEMENT | | 7587K| 3704 || 1 | SORT ORDER BY | | 7587K| 3704 ||* 2 | HASH JOIN OUTER | | 7587K| 822 ||* 3 | HASH JOIN OUTER | | 5262K| 616 ||* 4 | HASH JOIN OUTER | | 2980K| 465 ||* 5 | HASH JOIN OUTER | | 710K| 432 ||* 6 | HASH JOIN OUTER | | 398K| 302 || 7 | VIEW | ALL_TABLES | 342K| 276 || 29 | VIEW | ALL_MVIEWS | 51 | 20 || 50 | VIEW | ALL_PART_TABLES | 852K| 104 || 78 | VIEW | ALL_TAB_COMMENTS | 2043 | 14 || 93 | VIEW | ALL_EXTERNAL_LOCATIONS | 1744K| 31 || 106 | VIEW | ALL_EXTERNAL_TABLES | 1777K| 28 |------------------------------------------------------------------------------- That's much more like it. This drops the execution time down to 24 seconds. Not as good as 10g, but still an improvement. There are still several problems with this, however. 10g introduced a new join method - a right outer hash join (used in the first execution plan). The 9i query optimizer doesn't have this option available, so forcing a hash join means it has to hash the ALL_TABLES table, and furthermore re-hash it for every hash join in the execution plan; this could be thousands and thousands of rows. And although forcing hash joins somewhat alleviates this problem on our test systems, there's no guarantee that this will improve the execution time on customers' systems; it may even increase the time it takes (say, if all their tables are partitioned, or they've got a lot of materialized views). Ideally, we would want a solution that provides a speedup whatever the input. To try and get some ideas, we asked some oracle performance specialists to see if they had any ideas or tips. Their recommendation was to add a hidden hook into the product that allowed users to specify their own query hints, or even rewrite the queries entirely. However, we would prefer not to take that approach; as well as a lot of new infrastructure & a rewrite of the population code, it would have meant that any users of 9i would have to spend some time optimizing it to get it working on their system before they could use the product. Another approach was needed. All our population queries have a very specific pattern - a base table provides most of the information we need (ALL_TABLES for tables, or ALL_TAB_COLS for columns) and we do a left join to extra subsidiary tables that fill in gaps (for instance, ALL_PART_TABLES for partition information). All the left joins use the same set of columns to join on (typically the object owner & name), so we could re-use the hash information for each join, rather than re-hashing the same columns for every join. To allow us to do this, along with various other performance improvements that could be done for the specific query pattern we were using, we read all the tables individually and do a hash join on the client. Fortunately, this 'pure' algorithmic problem is the kind that can be very well optimized for expected real-world situations; as well as storing row data we're not using in the hash key on disk, we use very specific memory-efficient data structures to store all the information we need. This allows us to achieve a database population time that is as fast as on 10g, and even (in some situations) slightly faster, and a memory overhead of roughly 150 bytes per row of data in the result set (for schemas with 10,000 tables in that means an extra 1.4MB memory being used during population). Next: fun with the 9i dictionary views.

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• Cloud Computing Forces Better Design Practices

  - by Herve Roggero

  Is cloud computing simply different than on premise development, or is cloud computing actually forcing you to create better applications than you normally would? In other words, is cloud computing merely imposing different design principles, or forcing better design principles?  A little while back I got into a discussion with a developer in which I was arguing that cloud computing, and specifically Windows Azure in his case, was forcing developers to adopt better design principles. His opinion was that cloud computing was not yielding better systems; just different systems. In this blog, I will argue that cloud computing does force developers to use better design practices, and hence better applications. So the first thing to define, of course, is the word “better”, in the context of application development. Looking at a few definitions online, better means “superior quality”. As it relates to this discussion then, I stipulate that cloud computing can yield higher quality applications in terms of scalability, everything else being equal. Before going further I need to also outline the difference between performance and scalability. Performance and scalability are two related concepts, but they don’t mean the same thing. Scalability is the measure of system performance given various loads. So when developers design for performance, they usually give higher priority to a given load and tend to optimize for the given load. When developers design for scalability, the actual performance at a given load is not as important; the ability to ensure reasonable performance regardless of the load becomes the objective. This can lead to very different design choices. For example, if your objective is to obtains the fastest response time possible for a service you are building, you may choose the implement a TCP connection that never closes until the client chooses to close the connection (in other words, a tightly coupled service from a connectivity standpoint), and on which a connection session is established for faster processing on the next request (like SQL Server or other database systems for example). If you objective is to scale, you may implement a service that answers to requests without keeping session state, so that server resources are released as quickly as possible, like a REST service for example. This alternate design would likely have a slower response time than the TCP service for any given load, but would continue to function at very large loads because of its inherently loosely coupled design. An example of a REST service is the NO-SQL implementation in the Microsoft cloud called Azure Tables. Now, back to cloud computing… Cloud computing is designed to help you scale your applications, specifically when you use Platform as a Service (PaaS) offerings. However it’s not automatic. You can design a tightly-coupled TCP service as discussed above, and as you can imagine, it probably won’t scale even if you place the service in the cloud because it isn’t using a connection pattern that will allow it to scale [note: I am not implying that all TCP systems do not scale; I am just illustrating the scalability concepts with an imaginary TCP service that isn’t designed to scale for the purpose of this discussion]. The other service, using REST, will have a better chance to scale because, by design, it minimizes resource consumption for individual requests and doesn’t tie a client connection to a specific endpoint (which means you can easily deploy this service to hundreds of machines without much trouble, as long as your pockets are deep enough). The TCP and REST services discussed above are both valid designs; the TCP service is faster and the REST service scales better. So is it fair to say that one service is fundamentally better than the other? No; not unless you need to scale. And if you don’t need to scale, then you don’t need the cloud in the first place. However, it is interesting to note that if you do need to scale, then a loosely coupled system becomes a better design because it can almost always scale better than a tightly-coupled system. And because most applications grow overtime, with an increasing user base, new functional requirements, increased data and so forth, most applications eventually do need to scale. So in my humble opinion, I conclude that a loosely coupled system is not just different than a tightly coupled system; it is a better design, because it will stand the test of time. And in my book, if a system stands the test of time better than another, it is of superior quality. Because cloud computing demands loosely coupled systems so that its underlying service architecture can be leveraged, developers ultimately have no choice but to design loosely coupled systems for the cloud. And because loosely coupled systems are better… … the cloud forces better design practices. My 2 cents.

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• How can I estimate the entropy of a password?

  - by Wug

  Having read various resources about password strength I'm trying to create an algorithm that will provide a rough estimation of how much entropy a password has. I'm trying to create an algorithm that's as comprehensive as possible. At this point I only have pseudocode, but the algorithm covers the following: password length repeated characters patterns (logical) different character spaces (LC, UC, Numeric, Special, Extended) dictionary attacks It does NOT cover the following, and SHOULD cover it WELL (though not perfectly): ordering (passwords can be strictly ordered by output of this algorithm) patterns (spatial) Can anyone provide some insight on what this algorithm might be weak to? Specifically, can anyone think of situations where feeding a password to the algorithm would OVERESTIMATE its strength? Underestimations are less of an issue. The algorithm: // the password to test password = ? length = length(password) // unique character counts from password (duplicates discarded) uqlca = number of unique lowercase alphabetic characters in password uquca = number of uppercase alphabetic characters uqd = number of unique digits uqsp = number of unique special characters (anything with a key on the keyboard) uqxc = number of unique special special characters (alt codes, extended-ascii stuff) // algorithm parameters, total sizes of alphabet spaces Nlca = total possible number of lowercase letters (26) Nuca = total uppercase letters (26) Nd = total digits (10) Nsp = total special characters (32 or something) Nxc = total extended ascii characters that dont fit into other categorys (idk, 50?) // algorithm parameters, pw strength growth rates as percentages (per character) flca = entropy growth factor for lowercase letters (.25 is probably a good value) fuca = EGF for uppercase letters (.4 is probably good) fd = EGF for digits (.4 is probably good) fsp = EGF for special chars (.5 is probably good) fxc = EGF for extended ascii chars (.75 is probably good) // repetition factors. few unique letters == low factor, many unique == high rflca = (1 - (1 - flca) ^ uqlca) rfuca = (1 - (1 - fuca) ^ uquca) rfd = (1 - (1 - fd ) ^ uqd ) rfsp = (1 - (1 - fsp ) ^ uqsp ) rfxc = (1 - (1 - fxc ) ^ uqxc ) // digit strengths strength = ( rflca * Nlca + rfuca * Nuca + rfd * Nd + rfsp * Nsp + rfxc * Nxc ) ^ length entropybits = log_base_2(strength) A few inputs and their desired and actual entropy_bits outputs: INPUT DESIRED ACTUAL aaa very pathetic 8.1 aaaaaaaaa pathetic 24.7 abcdefghi weak 31.2 H0ley$Mol3y_ strong 72.2 s^fU¬5ü;y34G< wtf 88.9 [a^36]* pathetic 97.2 [a^20]A[a^15]* strong 146.8 xkcd1** medium 79.3 xkcd2** wtf 160.5 * these 2 passwords use shortened notation, where [a^N] expands to N a's. ** xkcd1 = "Tr0ub4dor&3", xkcd2 = "correct horse battery staple" The algorithm does realize (correctly) that increasing the alphabet size (even by one digit) vastly strengthens long passwords, as shown by the difference in entropy_bits for the 6th and 7th passwords, which both consist of 36 a's, but the second's 21st a is capitalized. However, they do not account for the fact that having a password of 36 a's is not a good idea, it's easily broken with a weak password cracker (and anyone who watches you type it will see it) and the algorithm doesn't reflect that. It does, however, reflect the fact that xkcd1 is a weak password compared to xkcd2, despite having greater complexity density (is this even a thing?). How can I improve this algorithm? Addendum 1 Dictionary attacks and pattern based attacks seem to be the big thing, so I'll take a stab at addressing those. I could perform a comprehensive search through the password for words from a word list and replace words with tokens unique to the words they represent. Word-tokens would then be treated as characters and have their own weight system, and would add their own weights to the password. I'd need a few new algorithm parameters (I'll call them lw, Nw ~= 2^11, fw ~= .5, and rfw) and I'd factor the weight into the password as I would any of the other weights. This word search could be specially modified to match both lowercase and uppercase letters as well as common character substitutions, like that of E with 3. If I didn't add extra weight to such matched words, the algorithm would underestimate their strength by a bit or two per word, which is OK. Otherwise, a general rule would be, for each non-perfect character match, give the word a bonus bit. I could then perform simple pattern checks, such as searches for runs of repeated characters and derivative tests (take the difference between each character), which would identify patterns such as 'aaaaa' and '12345', and replace each detected pattern with a pattern token, unique to the pattern and length. The algorithmic parameters (specifically, entropy per pattern) could be generated on the fly based on the pattern. At this point, I'd take the length of the password. Each word token and pattern token would count as one character; each token would replace the characters they symbolically represented. I made up some sort of pattern notation, but it includes the pattern length l, the pattern order o, and the base element b. This information could be used to compute some arbitrary weight for each pattern. I'd do something better in actual code. Modified Example: Password: 1234kitty$$$$$herpderp Tokenized: 1 2 3 4 k i t t y $ $ $ $ $ h e r p d e r p Words Filtered: 1 2 3 4 @W5783 $ $ $ $ $ @W9001 @W9002 Patterns Filtered: @P[l=4,o=1,b='1'] @W5783 @P[l=5,o=0,b='$'] @W9001 @W9002 Breakdown: 3 small, unique words and 2 patterns Entropy: about 45 bits, as per modified algorithm Password: correcthorsebatterystaple Tokenized: c o r r e c t h o r s e b a t t e r y s t a p l e Words Filtered: @W6783 @W7923 @W1535 @W2285 Breakdown: 4 small, unique words and no patterns Entropy: 43 bits, as per modified algorithm The exact semantics of how entropy is calculated from patterns is up for discussion. I was thinking something like: entropy(b) * l * (o + 1) // o will be either zero or one The modified algorithm would find flaws with and reduce the strength of each password in the original table, with the exception of s^fU¬5ü;y34G<, which contains no words or patterns.

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• Building a Repository Pattern against an EF 5 EDMX Model - Part 1

  - by Juan

  I am part of a year long plus project that is re-writing an existing application for a client.  We have decided to develop the project using Visual Studio 2012 and .NET 4.5.  The project will be using a number of technologies and patterns to include Entity Framework 5, WCF Services, and WPF for the client UI.This is my attempt at documenting some of the successes and failures that I will be coming across in the development of the application.In building the data access layer we have to access a database that has already been designed by a dedicated dba. The dba insists on using Stored Procedures which has made the use of EF a little more difficult.  He will not allow direct table access but we did manage to get him to allow us to use Views.  Since EF 5 does not have good support to do Code First with Stored Procedures, my option was to create a model (EDMX) against the existing database views.   I then had to go select each entity and map the Insert/Update/Delete functions to their respective stored procedure. The next step after I had completed mapping the stored procedures to the entities in the EDMX model was to figure out how to build a generic repository that would work well with Entity Framework 5.  After reading the blog posts below, I adopted much of their code with some changes to allow for the use of Ninject for dependency injection.http://www.tcscblog.com/2012/06/22/entity-framework-generic-repository/ http://www.tugberkugurlu.com/archive/generic-repository-pattern-entity-framework-asp-net-mvc-and-unit-testing-triangle IRepository.cs public interface IRepository : IDisposable where T : class { void Add(T entity); void Update(T entity, int id); T GetById(object key); IQueryable Query(Expression> predicate); IQueryable GetAll(); int SaveChanges(); int SaveChanges(bool validateEntities); } GenericRepository.cs public abstract class GenericRepository : IRepository where T : class { public abstract void Add(T entity); public abstract void Update(T entity, int id); public abstract T GetById(object key); public abstract IQueryable Query(Expression> predicate); public abstract IQueryable GetAll(); public int SaveChanges() { return SaveChanges(true); } public abstract int SaveChanges(bool validateEntities); public abstract void Dispose(); } One of the issues I ran into was trying to do an update. I kept receiving errors so I posted a question on Stack Overflow http://stackoverflow.com/questions/12585664/an-object-with-the-same-key-already-exists-in-the-objectstatemanager-the-object and came up with the following hack. If someone has a better way, please let me know. DbContextRepository.cs public class DbContextRepository : GenericRepository where T : class { protected DbContext Context; protected DbSet DbSet; public DbContextRepository(DbContext context) { if (context == null) throw new ArgumentException("context"); Context = context; DbSet = Context.Set(); } public override void Add(T entity) { if (entity == null) throw new ArgumentException("Cannot add a null entity."); DbSet.Add(entity); } public override void Update(T entity, int id) { if (entity == null) throw new ArgumentException("Cannot update a null entity."); var entry = Context.Entry(entity); if (entry.State == EntityState.Detached) { var attachedEntity = DbSet.Find(id); // Need to have access to key if (attachedEntity != null) { var attachedEntry = Context.Entry(attachedEntity); attachedEntry.CurrentValues.SetValues(entity); } else { entry.State = EntityState.Modified; // This should attach entity } } } public override T GetById(object key) { return DbSet.Find(key); } public override IQueryable Query(Expression> predicate) { return DbSet.Where(predicate); } public override IQueryable GetAll() { return Context.Set(); } public override int SaveChanges(bool validateEntities) { Context.Configuration.ValidateOnSaveEnabled = validateEntities; return Context.SaveChanges(); } #region IDisposable implementation public override void Dispose() { if (Context != null) { Context.Dispose(); GC.SuppressFinalize(this); } } #endregion IDisposable implementation } At this point I am able to start creating individual repositories that are needed and add a Unit of Work.  Stay tuned for the next installment in my path to creating a Repository Pattern against EF5.

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• Constrained A* problem

  - by Ragekit

  I've got a little problem with an A* algorithm that I need to Constrained a little bit. Basically : I use an A* to find the shortest path between 2 randomly placed room in 3D space, and then build a corridor between them. The problem I found is that sometimes it makes chimney like corridors that are not ideal, so I constrict the A* so that if the last movement was up or down, you go sideways. Everything is fine, but in some corner cases, it fails to find a path (when there is obviously one). Like here between the blue and red dot : (i'm in unity btw, but i don't think it matters) Here is the code of the actual A* (a bit long, and some redundency) while(current != goal) { //add stair up / stair down foreach(Node<GridUnit> test in current.Neighbors) { if(!test.Data.empty && test != goal) continue; //bug at arrival; if(test == goal && penul !=null) { Vector3 currentDiff = current.Data.bounds.center - test.Data.bounds.center; if(!Mathf.Approximately(currentDiff.y,0)) { //wanna drop on the last if(!coplanar(test.Data.bounds.center,current.Data.bounds.center,current.Data.parentUnit.bounds.center,to.Data.bounds.center)) { continue; } else { if(Mathf.Approximately(to.Data.bounds.center.x, current.Data.parentUnit.bounds.center.x) && Mathf.Approximately(to.Data.bounds.center.z, current.Data.parentUnit.bounds.center.z)) { continue; } } } } if(current.Data.parentUnit != null) { Vector3 previousDiff = current.Data.parentUnit.bounds.center - current.Data.bounds.center; Vector3 currentDiff = current.Data.bounds.center - test.Data.bounds.center; if(!Mathf.Approximately(previousDiff.y,0)) { if(!Mathf.Approximately(currentDiff.y,0)) { //you wanna drop now : continue; } if(current.Data.parentUnit.parentUnit != null) { if(!coplanar(test.Data.bounds.center,current.Data.bounds.center,current.Data.parentUnit.bounds.center,current.Data.parentUnit.parentUnit.bounds.center)) { continue; }else { if(Mathf.Approximately(test.Data.bounds.center.x, current.Data.parentUnit.parentUnit.bounds.center.x) && Mathf.Approximately(test.Data.bounds.center.z, current.Data.parentUnit.parentUnit.bounds.center.z)) { continue; } } } } } g = current.Data.g + HEURISTIC(current.Data,test.Data); h = HEURISTIC(test.Data,goal.Data); f = g + h; if(open.Contains(test) || closed.Contains(test)) { if(test.Data.f > f) { //found a shorter path going passing through that point test.Data.f = f; test.Data.g = g; test.Data.h = h; test.Data.parentUnit = current.Data; } } else { //jamais rencontré test.Data.f = f; test.Data.h = h; test.Data.g = g; test.Data.parentUnit = current.Data; open.Add(test); } } closed.Add (current); if(open.Count == 0) { Debug.Log("nothingfound"); //nothing more to test no path found, stay to from; List<GridUnit> r = new List<GridUnit>(); r.Add(from.Data); return r; } //sort open from small to biggest travel cost open.Sort(delegate(Node<GridUnit> x, Node<GridUnit> y) { return (int)(x.Data.f-y.Data.f); }); //get the smallest travel cost node; Node<GridUnit> smallest = open[0]; current = smallest; open.RemoveAt(0); } //build the path going backward; List<GridUnit> ret = new List<GridUnit>(); if(penul != null) { ret.Insert(0,to.Data); } GridUnit cur = goal.Data; ret.Insert(0,cur); do{ cur = cur.parentUnit; ret.Insert(0,cur); } while(cur != from.Data); return ret; You see at the start of the foreach i constrict the A* like i said. If you have any insight it would be cool. Thanks

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• 2012&ndash;The End Of The World Review

  - by Tim Murphy

  The end of the world must be coming.  Not because the Mayan calendar says so, but because Microsoft is innovating more than Apple.  It has been a crazy year, with pundits declaring not that the end of the world is coming, but that the end of Microsoft is coming.  Let’s take a look at what 2012 has brought us. The beginning of year is a blur.  I managed to get to TechEd in June which was the first time that I got to take a deep dive into Windows 8 and many other things that had been announced in 2011.  The promise I saw in these products was really encouraging.  The thought of being able to run Windows 8 from a thumb drive or have Hyper-V native to the OS told me that at least for developers good things were coming. I finally got my feet wet with Windows 8 with the developer preview just prior to the RTM.  While the initial experience was a bit of a culture shock I quickly grew to love it.  The media still seems to hold little love for the “reimagined” platform, but I think that once people spend some time with it they will enjoy the experience and what the FUD mongers say will fade into the background.  With the launch of the OS we finally got a look at the Surface.  I think this is a bold entry into the tablet market.  While I wish it was a little more affordable I am already starting to see them in the wild being used by non-techies. I was waiting for Windows Phone 8 at least as much as Windows 8, probably more.  The new hardware, better marketing and new OS features I think are going to finally push us to the point of having a real presence in the smartphone market.  I am seeing a number of iPhone users picking up a Nokia Lumia 920 and getting rid of their brand new iPhone 5.  The only real debacle that I saw around the launch was when they held back the SDK from general developers. Shortly after the launch events came Build 2012.  I was extremely disappointed that I didn’t make it to this year’s Build.  Even if they weren’t handing out Surface and Lumia devices I think the atmosphere and content were something that really needed to be experience in person.  Hopefully there will be a Build next year and it’s schedule will be announced soon.  As you would expect Windows 8 and Windows Phone 8 development were the mainstay of the conference, but improvements in Azure also played a key role.  This movement of services to the cloud will continue and we need to understand where it best fits into the solutions we build. Lower on the radar this year were Office 2013, SQL Server 2012, and Windows Server 2012.  Their glory stolen by the consumer OS and hardware announcements, these new releases are no less important.  Companies will see significant improvements in performance and capabilities if they upgrade.  At TechEd they had shown some of the new features of Windows Server 2012 around hardware integration and Hyper-V performance which absolutely blew me away.  It is our job to bring these important improvements to our company’s attention so that they can be leveraged. Personally, the consulting business in 2012 was the busiest it has been in a long time.  More companies were ready to attack new projects after several years of putting them on the back burner.  I also worked to bring back momentum to the Chicago Information Technology Architects Group.  Both the community and clients are excited about the new technologies that have come out in 2012 and now it is time to deliver. What does 2013 have in store.  I don’t see it be quite as exciting as 2012.  Microsoft will be releasing the Surface Pro in January and it seems that we will see more frequent OS update for Windows.  There are rumors that we may see a Surface phone in 2013.  It has also been announced that there will finally be a rework of the XBox next fall.  The new year will also be a time for us in the development community to take advantage of these new tools and devices.  After all, it is what we build on top of these platforms that will attract more consumers and corporations to using them. Just as I am 99.999% sure that the world is not going to end this year, I am also sure that Microsoft will move on and that most of this negative backlash from the media is actually fear and jealousy.  In the end I think we have a promising year ahead of us. del.icio.us Tags: Microsoft,Pundits,Mayans,Windows 8,Windows Phone 8,Surface

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