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• cloud programming for OpenStack in C / C++

  - by Basile Starynkevitch

  (Sorry for such a fuzzy question, I am very newbie to cloud programming) I am interested in designing (and developing) a (free software) program in C or C++ (probably, most of it being meta-programmed, i.e. part of the C code code being generated). I am still in the thinking / designing phase. And I might perhaps give up. For reference, I am the main architect and implementor of GCC MELT, a domain specific language to extend the GCC compiler (the MELT language is translated to C/C++ and is bootstrapped: the MELT to C/C++ translator being written in MELT). And I am dreaming of extending it with some cloud computing abilities. But I am a newbie in cloud computing. (I am only interested in free-software, GPLv3 friendly, based cloud computing, which probably means openstack). I believe that "compiling on the cloud with some enhanced GCC" could make sense (for super-optimizations or static analysis of e.g. an entire Linux distribution, or at least a massive GCC compiled free software like Qt, GCC itself, or the Linux kernel). I'm dreaming of a MELT specific monitoring program which would store, communicate, and and enhance GCC compilation (extended by MELT). So the picture would be that each GCC process (actually the cc1 or cc1plus started by the gcc driver, suitably extended by some MELT extension) would communicate with some monitor. That "monitoring/persisting" program would run "on the cloud" (and probably manage some information produced by GCC e.g. on NoSQL bases). So, how should some (yet to be written) C program (some Linux daemon) be designed to be cloud-friendly? So far, I understood that it should provide some Web service, probably thru a RESTful service, so should use an HTTP server library like onion. And that OpenStack is able to start (e.g. a dozen of) such services. But I don't have a clear picture of what OpenStack brings. So far, I noticed the ability to manage (and distribute) virtual machines (with some Python API). It is less clear how can it distribute some ELF executable, how can it start it, etc. Do you have any references or examples of C / C++ programming on the cloud? How should a "cloud-friendly" (actually, OpenStack friendly) C/C++ server application be designed?

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• Install 32-bit gstreamer plugins on 64-bit

  - by Rua

  I am trying to install the 32-bit gstreamer plugins on my 64-bit system (Ubuntu 12.10 based). I can install the packages gstreamer0.10-plugins-base:i386 and gstreamer0.10-plugins-good:i386. However, gstreamer0.10-plugins-bad:i386, gstreamer0.10-plugins-bad-multiverse:i386 and gstreamer0.10-plugins-ugly:i386 conflict with 64-bit packages already installed on my system: $ sudo apt-get install gstreamer0.10-plugins-bad:i386 Reading package lists... Done Building dependency tree Reading state information... Done Some packages could not be installed. This may mean that you have requested an impossible situation or if you are using the unstable distribution that some required packages have not yet been created or been moved out of Incoming. The following information may help to resolve the situation: The following packages have unmet dependencies: gstreamer0.10-plugins-bad:i386 : Depends: libass4:i386 (>= 0.9.7) but it is not going to be installed Depends: libdca0:i386 but it is not going to be installed Depends: libdvdnav4:i386 (>= 4.2.0+20120524) but it is not going to be installed Depends: libdvdread4:i386 but it is not going to be installed Depends: libslv2-9:i386 (>= 0.6.4-1~) but it is not going to be installed E: Unable to correct problems, you have held broken packages. ... $ sudo apt-get install gstreamer0.10-plugins-bad-multiverse:i386 Reading package lists... Done Building dependency tree Reading state information... Done The following extra packages will be installed: libavcodec53:i386 libavutil51:i386 libfaac0:i386 libfaad2:i386 libgsm1:i386 libmjpegtools-1.9:i386 libmp3lame0:i386 libquicktime2:i386 libschroedinger-1.0-0:i386 libswscale2:i386 libva1:i386 libvpx1:i386 libx264-123:i386 libxvidcore4:i386 The following packages will be REMOVED: gstreamer0.10-plugins-bad-multiverse libfaac0 libmjpegtools-1.9 mint-meta-codecs The following NEW packages will be installed: gstreamer0.10-plugins-bad-multiverse:i386 libavcodec53:i386 libavutil51:i386 libfaac0:i386 libfaad2:i386 libgsm1:i386 libmjpegtools-1.9:i386 libmp3lame0:i386 libquicktime2:i386 libschroedinger-1.0-0:i386 libswscale2:i386 libva1:i386 libvpx1:i386 libx264-123:i386 libxvidcore4:i386 0 upgraded, 15 newly installed, 4 to remove and 5 not upgraded. Need to get 9,198 kB of archives. After this operation, 23.3 MB of additional disk space will be used. Do you want to continue [Y/n]? ... $ sudo apt-get install gstreamer0.10-plugins-ugly:i386 Reading package lists... Done Building dependency tree Reading state information... Done Some packages could not be installed. This may mean that you have requested an impossible situation or if you are using the unstable distribution that some required packages have not yet been created or been moved out of Incoming. The following information may help to resolve the situation: The following packages have unmet dependencies: gstreamer0.10-plugins-ugly:i386 : Depends: libdvdread4:i386 but it is not going to be installed E: Unable to correct problems, you have held broken packages. This means that I can't play mp3s (among other things) in 32-bit applications that use gstreamer. Is there a way around this?

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• Modelling highly specific business requirements

  - by AndyBursh

  How can one go about modelling highly specific business requirements, which have no precedent in the system? Take for example the following requirement: When a purchase order contains N lines, is over X value in total and is being recorded against project Y, an email needs to be sent to persons A and B with the details This requirement supplements other requirements surrounding purchase orders, but comes in at a much later date in response to some ongoing problem elsewhere in the business. Persons A and B are not part of any role or group in the system, and don't hold any specific responsibility; they are simply the two people the business has appointed to receive these emails in this very specific case. Projects are also data driven, so project Y has no special properties to distinguish it from any other project. The only way to identify it is to compare its identifier to a magic number. How can one go about modelling this kind of case without introducing too much additional complexity? That I can think of right now, there are a couple of options. Perform the checks and actions inline with the existing code. Here we find the correct spot in the code, check the conditions in the requirement and send the emails to hardcoded addresses. Of course this is fraught with issues. At the very least it stops working if one of these people leaves or changes their email address. At worst you have to ensure that any tests and test data are aware that additional actions are taken for a specific set of criteria. Introduce some form of events system. Here we introduce an eventing system, so that we might react to some event, and fulfil the requirement outside of the usual path of execution. This sounds like a cleaner solution than option 1, but the work involved is ultimately probably slightly overkill for this one small requirement. That said, having it in place does allow the system to handle these kinds of specific requirements consistently and easily in the future. Are there any other (good/better) ways of handling highly specific requirements? I mean other than telling the other parts of the business no!

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• MSFT new trick to promote IE9 by kill IE6 first.

  - by anirudha

  Every developer know every issue on development for IE6 whenever they know things more. they are frustrated whenever they spent time in IE6 for making application cross browser compatible. not long time ago MSFT make a campaign save IE6 you can find the reference http://blogs.msdn.com/b/anna/archive/2009/04/01/save-internet-explorer-6.aspx and the webstite is here http://www.saveie6.com/ well they really make joke see what they write on the page. well why website maked in PHP whenever they can make them in asp.net or any other technology who reflect the Microsoft technology see here  http://www.saveie6.com/compare.php High security (many updates) :- you can find IE6 is how much secure you can also read Wikipedia for know. well i can say IE6 is very easily to hack. wikipedia tell you about that here http://en.wikipedia.org/wiki/Internet_Explorer_6 and for know about the security watch here http://www.google.co.in/webhp?hl=en#sclient=psy&hl=en&site=webhp&q=ie6+security+issues Lightweight (no support for silly PNG transparency, etc) :- well they tell PNG silly but tell me about the best format on internet. their is no better option as png or SVG. More screen space thanks to no tabs:-  they tell this nonsense without think anything. if they really care about more screen space why they make tab  in 7,8,9. conclusion:- IE team make a research on how to promote IE9 better then they can beat chrome and Firefox. because IE9 not have anything good like customization , plug-in ,add-ons , personas , themes and many other thing like chrome and Firefox provided perhaps IE is outdated thing even everyone their can writing about these days that IE9 have this, have performance better then this… the main problem in IE is IE6. many developer hate them because many of their time goes for making site cross browser compatible. in 2009 they still have no blah like IE9 who they have today so they make a campaign for save IE6. the list they make is a joke. they show that everything in IE6 is perfect even everyone know the truth. they listed IE6 is high security. in 2011 their is a problem for IE9 promotion called IE6. because developer hate IE6 how they can promote IE9 very well. so destroy IE6 is only option for IE9 make promote better. so you can see they make two different different campaign and both are opposite of other. well  how we can believe in IE9. thanks for reading this post. what you thinking on it. have a idea or feedback reported them.

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• Business Insight, IT Execution: 9 Project Management Tips

  - by Sylvie MacKenzie, PMP

  Excerpt from Profit Magazine - by David Rosenbaum When Marcos Baccetto was first asked to be the business-side project lead on Eaton Corporation’s Vehicle Group South America (VGSA) Oracle project, the operations services manager responsible for running manufacturing was, he confesses, “a little afraid” because of his lack of IT experience. Today, Baccetto calls the project “a fantastic experience,” and he is a true believer in the benefits of a close relationship between IT implementers and their line-of-business peers. Through his partnership with Jesiele Lima, then VGSA IT manager, Baccetto and Eaton’s South American operations team came to understand several important principles of business and IT. Here he shares nine tips managers should consider when working on an enterprise technology project. 1. Make it a business project, not an IT project. All levels of functional management must have ownership, responsibility, and accountability for the success of the implementation. 2. Share responsibility. Business owners should sign off on tests and data conversion. 3. Clean your data. Dedicating a team to improve core data quality prior to project launch can be a significant time-saver. 4. Select resources properly. Have functional people who can translate business needs to IT and can influence organizational change. 5. Manage scope. Follow project management methodologies and disciplines. 6. Adopt common processes, global solutions. Avoid customized, local solutions. The big-picture business goals can get lost in the details. 7. Implement processes prior to the go-live date. Change management can be key. Keep the workforce informed and train users in advance. 8. Define metrics milestones. Assume there will be a crisis during deployment. Having baseline metrics to compare against will help implementers keep their cool—and the project moving forward. 9. The sponsor’s commitment is critical. It is needed to support the truly difficult decisions.

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• Is Infiniband going to get squeezed by iWARP and external QPI?

  - by andy.grover

  The Inquirer certainly thinks so.However, I'm not so sure it makes sense to compare Infiniband to an as-yet-unannounced optical external QPI. QPI is currently a processor interconnect. CPUs, RAM, and devices connected by it are conceptually part of the same machine -- they run a single OS, for example. They are both "networks" or "fabrics" but they have very different design trade-offs.Another widely-used bus in the system is closer to Infiniband than QPI -- PCI Express. Isn't it more likely that PCIe could take on IB? There are companies already who have solutions that use external PCI Express for cluster interconnect, but these have not gained significant market share. Why would QPI, a technology whose sweet spot is even further from Infiniband's than PCIe, be able to challenge Infiniband? It's hard to speculate without much information, but right now it doesn't seem likely to me.The other prediction made in the article is that Intel's 10GbE iWARP card could squeeze IB on the low end, due to its greater compatibility and lower cost.It's definitely never a good idea to bet against Ethernet when it comes to mass-market, commodity networking. Ethernet will win. 10GbE will win. But, there are now two competing ways to implement the low-latency RDMA Verbs interface on top of Ethernet. iWARP is essentially RDMA over TCP/IP over Ethernet. The new alternative is IBoE (Infiniband over Ethernet, aka RoCEE, aka "Rocky"). This encapsulates the IB packet protocol directly in the Ethernet frame. It loses the layer 3 routability of iWARP, but better maintains software compatibility with existing apps that use IB, and is simpler to implement in both software and hardware. iWARP has a substantial head start, but I believe that IBoE silicon will eventually be cheaper, and more likely to be implemented in commodity Ethernet hardware.I think IBoE is going to take low-end market share from traditional IB, but I think this is a situation IB hardware vendors have no problem accepting. Commoditized IBoE NICs invite greater use of RDMA features, and when higher performance is needed, customers can upgrade to "real" IB, maintaining IB's justification for higher prices. (IB max interconnect speeds have historically been 2-4x higher than Ethernet, and I don't see that changing.)(ObDisclosure: My current employer now sells IB hardware. I previously also worked at Intel. My opinions are my own, duh.)

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• Enabling EUS support in OUD 11gR2 using command line interface

  - by Sylvain Duloutre

  Enterprise User Security (EUS) allows Oracle Database to use users & roles stored in LDAP for authentication and authorization.Since the 11gR2 release, OUD natively supports EUS. EUS can be easily configured during OUD setup. ODSM (the graphical admin console) can also be used to enable EUS for a new suffix. However, enabling EUS for a new suffix using command line interface is currently not documented, so here is the procedure: Let's assume that EUS support was enabled during initial setup.Let's o=example be the new suffix I want to use to store Enterprise users. The following sequence of command must be applied for each new suffix: // Create a local database holding EUS context infodsconfig create-workflow-element --set base-dn:cn=OracleContext,o=example --set enabled:true --type db-local-backend --element-name exampleContext -n // Add a workflow element in the call path to generate on the fly attributes required by EUSdsconfig create-workflow-element --set enabled:true --type eus-context --element-name eusContext --set next-workflow-element:exampleContext -n // Add the context to a workflow for routingdsconfig create-workflow --set base-dn:cn=OracleContext,o=example --set enabled:true --set workflow-element:eusContext --workflow-name exampleContext_workflow -n //Add the new workflow to the appropriate network groupdsconfig set-network-group-prop --group-name network-group --add workflow:exampleContext_workflow -n // Create the local database for o=exampledsconfig create-workflow-element --set base-dn:o=example --set enabled:true --type db-local-backend --element-name example -n // Create a workflow element in the call path to the user data to generate on the fly attributes expected by EUS dsconfig create-workflow-element --set enabled:true --set eus-realm:o=example --set next-workflow-element:example --type eus --element-name eusWfe// Add the db to a workflow for routingdsconfig create-workflow --set base-dn:o=example --set enabled:true --set workflow-element:eusWfe --workflow-name example_workflow -n //Add the new workflow to the appropriate network groupdsconfig set-network-group-prop --group-name network-group --add workflow:example_workflow -n  // Add the appropriate acis for EUSdsconfig set-access-control-handler-prop \           --add global-aci:'(target="ldap:///o=example")(targetattr="authpassword")(version 3.0; acl "EUS reads authpassword"; allow (read,search,compare) userdn="ldap:///??sub?(&(objectclass=orclservice)(objectclass=orcldbserver))";)' dsconfig set-access-control-handler-prop \       --add global-aci:'(target="ldap:///o=example")(targetattr="orclaccountstatusevent")(version 3.0; acl "EUS writes orclaccountstatusenabled"; allow (write) userdn="ldap:///??sub?(&(objectclass=orclservice)(objectclass=orcldbserver))";)' Last but not least you must adapt the content of the ${OUD}/config/EUS/eusData.ldif  file with your suffix value then inport it into OUD.

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• The Other Side of XBRL

  - by john.orourke(at)oracle.com

  With the United States SEC's mandate for XBRL filings entering its third year, and impacting over 7000 additional companies in 2011, there's a lot of buzz in the industry about how companies should address the new reporting requirements.  Should they outsource the XBRL tagging process to a third party publisher, handle the process in-house with a bolt-on XBRL tool, or should they integrate XBRL tagging with the financial close and reporting process?  Oracle is recommending the latter approach, in fact  here's a link to a recent webcast that I did with CFO.com on this topic: http://www.cfo.com/webcasts/index.cfm/l_eventarchive/14548560 But production of XBRL-based filings is only half of the story. The other half is consumption of XBRL by regulators, academics, financial analysts and investors.  As I mentioned in my December article on the XBRL US conference, the feedback from these groups is that they are not really leveraging XBRL for analysis of companies due to a lack of tools and historic XBRL-based data on public companies.   The good news here is that the historic data problem is getting better as large, accelerated filers enter their third year of XBRL filings.  And the situation is getting better on the reporting and analysis tools side of the equation as well - and Oracle is leading the way. In early January, Oracle released the Oracle XBRL Extension for Oracle Database 11g.  This is a "no cost option" on top of the latest Oracle Database 11.2.0.2.0 release. With this added functionality organizations will have the ability to create one or more back-end XBRL repositories based on Oracle Database, which provide XBRL storage and query-ability with a set of XBRL-specific services.  The XBRL Extension to Oracle XML DB integrates easily with Oracle Business Intelligence Suite Enterprise Edition (OBIEE) for analytics and with interactive development environments (IDEs) and design tools for creating and editing XBRL taxonomies. The Oracle XBRL Extension to Oracle Database 11g should be attractive to regulators, stock exchanges, universities and other organizations that need to collect, analyze and disseminate XBRL-based filings.  It should also be attractive to organizations that produce XBRL filings, and need a way to store and compare their own XBRL-based financial filings to those of their peers and competitors. If you would like more information, here's a link to a web page on the Oracle Technology Network with the details about Oracle XBRL Extension for Oracle Database 11g, including data sheet, white paper, presentation, demos and other information: http://www.oracle.com/technetwork/database/features/xmldb/index-087631.html

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• ANTS Memory Profiler 7.0

  - by Sam Abraham

  In the next few lines, I would like to briefly review ANTS Memory Profiler 7.0.  I was honored to be extended the opportunity to review this valuable tool as part of the GeeksWithBlogs influencers Program, a quarterly award providing its recipients access to valuable tools and enabling them with an opportunity to provide a brief write-up reviewing the complimentary tools they receive.   Typical Usage   ANTS Memory Profiler 7.0 is very intuitive and easy to use for any user be it novice or expert. A simple yet comprehensive menu screen enables the selection of the appropriate program type to profile as well as the executable or site for this program.   A typical use case starts with establishing a baseline memory snapshot, which tells us the initial memory cost used by the program under normal or low activity conditions. We would then take a second snapshot after the program has performed an activity which we want to investigate for memory leaks. We can then compare the initial baseline snapshot against the snapshot when the program has completed processing the activity in question to study anomalies in memory that did not get freed-up after the program has completed its performed function. The following are some screenshots outlining the selection of the program to profile (an executable for this demonstration’s purposes).   Figure 1 - Getting Started   Figure 2 - Selecting an Application to Profile     Features and Options   Right after the second snapshot is generated, Memory Profiler gives us immediate access to information on memory fragmentation, size differences between snapshots, unmanaged memory allocation and statistics on the largest classes taking up un-freed memory space.   We would also have the option to itemize objects held in memory grouped by object types within which we can study the instances allocated of each type. Filtering options enable us to quickly narrow object instances we are interested in.   Figure 3 - Easily accessible Execution Memory Information   Figure 4 - Class List   Figure 5 - Instance List   Figure 6-  Retention Graph for a Particular Instance   Conclusion I greatly enjoyed the opportunity to evaluate ANTS Memory Profiler 7.0. The tool's intuitive User Interface design and easily accessible menu options enabled me to quickly identify problem areas where memory was left unfreed in my code.     Tutorials and References  FInd out more About ANTS Memory Profiler 7.0 http://www.red-gate.com/supportcenter/Product?p=ANTS Memory Profiler   Checkout what other reviewers of this valuable tool have already shared: http://geekswithblogs.net/BlackRabbitCoder/archive/2011/03/10/ants-memory-profiler-7.0.aspx http://geekswithblogs.net/mikebmcl/archive/2011/02/28/ants-memory-profiler-7.0-review.aspx

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• 3 Reasons You Need To Know Something About Every Technology

  - by Tim Murphy

  I make my living as a consultant and a general technologist.  I credit my success to the fact that I have never been afraid to pick up any product, language or platform needed to get the job done.  While Microsoft technologies I my mainstay, I have done work on mainframe and UNIX platforms and have worked with a wide variety of database engines.  Each one has it’s use and most times it is less expensive to find a way to communicate with an existing system than to replace it. So what are the main benefits of expending the effort to learn a new technology? New ways to solve problems Accelerate development Advise clients and get new business opportunities By new technology I mean ones that you haven’t had experience with before.  They don’t have to be the the one that just came out yesterday.  As they say, those who do not learn from history are bound to repeat it.  If you can learn something from an older technology it can be just as valuable as the shiny new one.  Either way, when you add another tool to your kit you get a new view on each problem you face.  This makes it easier to create a sound solution. The next thing you can learn from working with different products and techniques is how to more efficiently develop solve problems.  Many times if you are working with a new language you will find that there are specific design patterns that are used with it in normal use.  These can usually be applied with most languages.  You just needed to be exposed to them. The last point is about helping your clients and helping yourself.  If you can get in on technologies early you will have advantage over your competition in the market.  You will also be able to honestly advise you client on why they should or should not go with a new product.  Being able to compare products and their features is always an ability that stake holders appreciate. You don’t need to learn every detail of a product.  Learn enough to function and get an idea of how to use the technology.  Keep eating those technology Wheaties and you will be ready to go the distance in any project. del.icio.us Tags: Technology,technologists,technology generalist,Software Architecture

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• Managing Regulated Content in WebCenter: USDM and Oracle Offer a New Part 11 Compliant Solution for Life Sciences

  - by Michael Snow

  Guest post today provided by Oracle partner, USDM  Regulated Content in WebCenterUSDM and Oracle offer a new Part 11 compliant solution for Life Sciences (White Paper) Life science customers now have the ability to take advantage of all of the benefits of Oracle’s WebCenter Content, a global leader in Enterprise Content Management.   For the past year, USDM has been developing best practice compliance solutions to meet regulated content management requirements for 21 CFR Part 11 in WebCenter Content. USDM has been an expert in ECM for life sciences since 1999 and in 2011, certified that WebCenter was a 21CFR Part 11 compliant content management platform (White Paper).  In addition, USDM has built Validation Accelerators Packs for WebCenter to enable life science organizations to quickly and cost effectively validate this world class solution.With the Part 11 certification, Oracle’s WebCenter now provides regulated life science organizations  the ability to manage REGULATORY content in WebCenter, as well as the ability to take advantage of ALL of the additional functionality of WebCenter, including  a complete, open, and integrated portfolio of portal, web experience management, content management and social networking technology.  Here are a few screen shot examples of Part 11 functionality included in the product: E-Sign, E-Sign Rendor, Meta Data History, Audit Trail Report, and Access Reporting. Gone are the days that life science companies have to spend millions of dollars a year to implement, maintain, and validate ECM systems that no longer meet the ever changing business and regulatory requirements.  Life science companies now have the ability to use WebCenter Content, an ECM system with a substantially lower cost of ownership and unsurpassed functionality.Oracle has been #1 in life sciences because of their ability to develop cost effective, easy-to-use, scalable solutions which help increase insight and efficiency to drive growth for their customers.  Adding a world class ECM solution to this product portfolio allows life science organizations the chance to get rid of costly ECM systems that no longer meet their needs and use WebCenter, part of the Oracle Fusion Technology stack, with their other leading enterprise applications.USDM provides:•    Expertise in Life Science ECM Business Processes•    Prebuilt Life Science Configuration in WebCenter •    Validation Accelerator Packs for WebCenterUSDM is very proud to support Oracle’s expanding commitment to Life Sciences…. For more information please contact:  [email protected] Oracle will be exhibiting at DIA 2012 in Philadelphia on June 25-27. Stop by our booth (#2825) to learn more about the advantages of a centralized ECM strategy and see the Oracle WebCenter Content solution, our 21 CFR Part 11 compliant content management platform.

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• Methodology to understanding JQuery plugin & API's developed by third parties

  - by Taoist

  I have a question about third party created JQuery plug ins and API's and the methodology for understanding them. Recently I downloaded the JQuery Masonry/Infinite scroll plug in and I couldn't figure out how to configure it based on the instructions. So I downloaded a fully developed demo, then manually deleted everything that wouldn't break the functionality. The code that was left allowed me to understand the plug in much greater detail than the documentation. I'm now having a similar issue with a plug in called JQuery knob. http://anthonyterrien.com/knob/ If you look at the JQuery Knob readme file it says this is working code: $(function() { $('.dial') .trigger( 'configure', { "min":10, "max":40, "fgColor":"#FF0000", "skin":"tron", "cursor":true } ); }); But as far as I can tell it isn't at all. The read me also says the Plug in uses Canvas. I am wondering if I am suppose to wrap this code in a canvas context or if this functionality is already part of the plug in. I know this kind of "question" might not fit in here but I'm a bit confused on the assumptions around reading these kinds of documentation and thought I would post the query regardless. Curious to see if this is due to my "newbi" programming experience or if this is something seasoned coders also fight with. Thank you. Edit In response to Tyanna's reply. I modified the code and it still doesn't work. I posted it below. I made sure that I checked the Google Console to insure the basics were taken care of, such as not getting a read-error on the library. <!DOCTYPE html> <meta charset="UTF-8"> <title>knob</title> <link rel="stylesheet" href="http://ajax.googleapis.com/ajax/libs/jqueryui/1.7.2/themes/hot-sneaks/jquery-ui.css" type="text/css" /> <script type="text/javascript" src="https://ajax.googleapis.com/ajax/libs/jquery/1.7.2/jquery.js" charset="utf-8"></script> <script src="https://ajax.googleapis.com/ajax/libs/jqueryui/1.8.21/jquery-ui.min.js"></script> <script src="js/jquery.knob.js"></script> <div id="button1">test </div> <script> $(function() { $("#button1").click(function () { $('.dial').trigger( 'configure', { "min":10, "max":40, "fgColor":"#FF0000", "skin":"tron", "cursor":true } ); }); }); </script>

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• Agile Documentation

  - by Nick Harrison

  We all know that one of the premises of the agile manifesto is to value Working Software over Comprehensive Documentation. This is a wonderful idea and it takes a tremendous burden off of project implementations. I have seen as many projects fail because of the maintenance weight of the project documentations as I have for any reason. But this goal as important as it is may not always be practical. Sometimes the client will simply insist on tedious documentation despite the arguments against it. This may be to calm a nervous client. This may be to satisfy an audit / compliance requirement. This may be a non-too subtle attempt at sabotaging the project. Ok, it is probably not an all out attempt to sabotage the project, but it will probably feel that way. So what can we do to keep to the spirit of the Agile Manifesto but still meet the needs of the client wanting the documentation? This is a good question that I have been puzzling over lately! I hope to explore some possible answers more fully here. A common theme that my solutions are likely to follow is the same theme that I often follow with simplifying complex business logic. Make it table driven! My thought is that the sought after documentation could be a report or reports out of a metadata repository. Reports are much easier to maintain than hand written documentation. Here are a few additional advantages that we can explore over time: Reports will take advantage of the fact that different people have different needs and different format requirements Reports and the supporting metadata are more easily validated and the validation can be automated. If the application itself uses this metadata than there never has to be a question as to whether or not the metadata is up to date. It is up to date or the application would not work. In many cases we should be able to automatically gather most of the Meta data that we need using reflection, system tables, etc. I think that this will lower the total cost of ownership for the documentation and may provide something useful beyond having a pretty document to look at.  What are your thoughts?

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• How to interview a natural scientist for a dev position?

  - by Silas

  I already did some interviews for my company, mostly computer scientists for dev positions but also some testers and project managers. Now I have to fill a vacancy in our research group within the R&D department (side note: “research” means that we try to solve problems in our professional domain/market niche using software in research projects together with universities, other companies, research centres and end user organisations. It’s not computer science research; we’re not going to solve the P=NP problem). Now we invited a guy holding an MSc in chemistry (with a lot of physics in his CV, too), who never had any computer science lesson. I already talked with him about half an hour at a local university’s career days and there’s no doubt the guy is smart. Also his marks are excellent and he graduated with distinction. For his BSc he needed to teach himself programming in Mathematica and told me believably that he liked programming a lot. Also he solved some physical chemistry problem that I probably don’t understand using his own software, implemented in Mathematica, for his MSc thesis. It includes a GUI and a notable size of 8,000 LoC. He seems to be very attracted by what we’re doing in our research group and to be honest it’s quite difficult for an SME like us to get good people. I also am very interested in hiring him since he could assist me in writing project proposals, reports, doing presentations and so on. He would probably fit to our team, too. The only question left is: How can I check if he will get the programming skills he needs to do software implementation in our projects since this will be a significant part of the job? Of course I will ask him what it is, that is fascinating him about programming. I’ll also ask how he proceeded to write his natural science software and how he structured it. I’ll ask about how he managed to obtain the skills and information about software development he needed. But is there something more I could ask? Something more concrete perhaps? Should I ask him to explain his Mathematica solution? To be clear: I’m not looking for knowledge in a particular language or technology stack. We’re a .NET shop in product development but I want to have a free choice for our research projects. So I’m interested in the meta-competence being able to learn whatever is actually needed. I hope this question is answerable and not open-ended since I really like to know if there is a default way to check for the ability to get further programming skills on the job. If something is not clear to you please give me some comments and let me improve my question.

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• Validate if aTextBox Value Start with a Specific Letter

  - by Vincent Maverick Durano

  In case you will be working on a page that needs to validate the first character of the TextBox entered by a user then here are two options that you can use: Option 1: Using an array   1: <asp:Content ID="Content1" ContentPlaceHolderID="HeadContent" runat="server"> 2: <script type="text/javascript"> 3: function CheckFirstChar(o) { 4: var arr = ['A', 'B', 'C', 'D']; 5: if (o.value.length > 0) { 6: for (var i = 0; i < arr.length; i++) { 7: if (o.value.charAt(0) == arr[i]) { 8: alert('Valid'); 9: return true; 10: } 11: else { 12: alert('InValid'); 13: return false; 14: } 15: } 16: } 17: } 18: </script> 19: </asp:Content> 20: <asp:Content ID="Content2" ContentPlaceHolderID="MainContent" runat="server"> 21: <asp:TextBox ID="TextBox1" runat="server" onblur="return CheckFirstChar(this);"></asp:TextBox> 22: </asp:Content>   The example above uses an array of string for storing the list of  characters that a TextBox value should start with. We then iterate to the array and compare the first character of TextBox value to see if it matches any characters from the array. Option 2: Using Regular Expression (Preferred way)   1: <asp:Content ID="Content1" ContentPlaceHolderID="HeadContent" runat="server"> 2: <script type="text/javascript"> 3: function CheckFirstChar(o) { 4: pattern = /^(A|B|C|D)/; 5: if (!pattern.test(o.value)) { 6: alert('InValid'); 7: return false; 8: } else { 9: alert('Valid'); 10: return true; 11: } 12: } 13: </script> 14: </asp:Content> 15: <asp:Content ID="Content2" ContentPlaceHolderID="MainContent" runat="server"> 16: <asp:TextBox ID="TextBox1" runat="server" onblur="return CheckFirstChar(this);"></asp:TextBox> 17: </asp:Content>   The example above uses regular expression with the pattern  /^(A|B|C|D)/. This will check if the TextBox value starts with A,B,C or D. Please note that it's case sensitive. If you want to allow lower case then you can alter the patter to this /^(A|B|C|D)/i. The i in the last part will cause a case-insensitive search.   That's it! I hope someone find this post useful!

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• JGridView (Part 2)

  - by Geertjan

  The second sample in the JGrid download is a picture viewer that needs to be seen to be believed. Here it is, integrated into a NetBeans Platform application (click to enlarge it): When you mouse over the images, they change, showing several different images instantaneously. Here's the explorer view above, mainly making use of code from the sample: public class JGridView extends JScrollPane { @Override public void addNotify() { super.addNotify(); final ExplorerManager em = ExplorerManager.find(this); if (em != null) { final JGrid grid = new JGrid(); Node root = em.getRootContext(); final Node[] nodes = root.getChildren().getNodes(); final PicViewerObject[] pics = new PicViewerObject[nodes.length]; for (int i = 0; i < nodes.length; i++) { Node node = nodes[i]; pics[i] = node.getLookup().lookup(PicViewerObject.class); } grid.getCellRendererManager().setDefaultRenderer(new PicViewerRenderer()); grid.setModel(new DefaultListModel() { @Override public int getSize() { return pics.length; } @Override public Object getElementAt(int i) { return pics[i]; } }); grid.setFixedCellDimension(160); grid.addMouseMotionListener(new MouseAdapter() { int lastIndex = -1; @Override public void mouseMoved(MouseEvent e) { if (lastIndex >= 0) { Object o = grid.getModel().getElementAt(lastIndex); if (o instanceof PicViewerObject) { Rectangle r = grid.getCellBounds(lastIndex); if (r != null && !r.contains(e.getPoint())) { ((PicViewerObject) o).setMarker(false); grid.repaint(r); } } } int index = grid.getCellAt(e.getPoint()); if (index >= 0) { Object o = grid.getModel().getElementAt(index); if (o instanceof PicViewerObject) { Rectangle r = grid.getCellBounds(index); if (r != null) { ((PicViewerObject) o).setFraction(((float) e.getPoint().x - (float) r.x) / (float) r.width); ((PicViewerObject) o).setMarker(true); lastIndex = index; grid.repaint(r); } } } } }); grid.getSelectionModel().addListSelectionListener(new ListSelectionListener() { @Override public void valueChanged(ListSelectionEvent e) { //Somehow compare the selected item //with the list of books and find a matching book: int selectedIndex = grid.getSelectedIndex(); for (int i = 0; i < nodes.length; i++) { int picId = pics[i].getId(); if (selectedIndex == picId) { try { em.setSelectedNodes(new Node[]{nodes[i]}); } catch (PropertyVetoException ex) { Exceptions.printStackTrace(ex); } } } } }); setViewportView(grid); } } } The next step is to create a generic JGridView that will handle any kind of object automatically.

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• Showrooming: What's the big deal?

  - by David Dorf

  There's been lots of chatter recently on how retailers will combat showrooming this holiday season.  Best Buy and Target, for example, plan to price-match certain online sites.  But from my perspective, the whole showrooming concept is overblown.  Yes, mobile phones make is easier to comparison-shop, but consumers have been doing that all along.  Retailers have to work hard to merchandise their stores with the right products at the right price with the right promotions.  Its Retail 101. Yeah ok, many websites don't have to charge tax so they have an advantage, but they also have to cover shipping costs. Brick-and-mortar stores have the opportunity to provide expertise, fit, and instant gratification all of which are pretty big advantages. I see lots of studies that claim a large percentage of shoppers are showrooming.  Now I don't do much shopping, but when I do I rarely see anyone scanning UPC codes in the aisles.  If you dig into those studies, the question is usually something like, "have you used your mobile phone to price compare while shopping in the last year."  Well yeah, I did it once -- out of the 20 shopping trips.  And by the way, the in-store price was close enough to just buy the item.  Based on casual observation and informal surveys of friends, showrooming is not the modus-operandi for today's busy shoppers. I never see people showrooming in grocery stores, and most people don't bother for fashion.  For big purchases like appliances and furniture, I bet most people do their research online before entering the store.  The cases where I've done it was to see if a promotion was in fact a good deal.  Or even to make sure the in-store price is the same as the online price for the same brand. So, if you think you're a victim of showrooming, I suggest you look at the bigger picture.  Are you providing an engaging store experience?  Are you allowing customers to shop the way they want to shop, using various touchpoints?  Are you monitoring the competition to ensure prices are competitive?  Are your promotions attracting the right customers? Hubert Jolly, CEO of Best Buy, recently commented that showrooming might just get more people into his stores. "Once customers are in our stores, they're ours to lose."

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• So, I though I wanted to learn frontend/web development and break out of my comfort zone...

  - by ripper234

  I've been a backend developer for a long time, and I really swim in that field. C++/C#/Java, databases, NoSql, caching - I feel very much at ease around these platforms/concepts. In the past few years, I started to taste end-to-end web programming, and recently I decided to take a job offer in a front end team developing a large, complex product. I wanted to break out of my comfort zone and become more of an "all around developer". Problem is, I'm getting more and more convinced I don't like it. Things I like about backend programming, and missing in frontend stuff: More interesting problems - When I compare designing a server that handle massive data, to adding another form to a page or changing the validation logic, I find the former a lot more interesting. Refactoring refactoring refactoring - I am addicted to Visual Studio with Resharper, or IntelliJ. I feel very comfortable writing code as it goes without investing too much thought, because I know that with a few clicks I can refactor it into beautiful code. To my knowledge, this doesn't exist at all in javascript. Intellisense and navigation - I hate looking at a bunch of JS code without instantly being able to know what it does. In VS/IntelliJ I can summon the documentation, navigate to the code, climb up inheritance hiererchies ... life is sweet. Auto-completion - Just hit Ctrl-Space on an object to see what you can do with it. Easier to test - With almost any backend feature, I can use TDD to capture the requirements, see a bunch of failing tests, then implement, knowing that if the tests pass I did my job well. With frontend, while tests can help a bit, I find that most of the testing is still manual - fire up that browser and verify the site didn't break. I miss that feeling of "A green CI means everything is well with the world." Now, I've only seriously practiced frontend development for about two months now, so this might seem premature ... but I'm getting a nagging feeling that I should abandon this quest and return to my comfort zone, because, well, it's so comfy and fun. Another point worth mentioning in this context is that while I am learning some frontend tools, a lot of what I'm learning is our company's specific infrastructure, which I'm not sure will be very useful later on in my career. Any suggestions or tips? Do you think I should give frontend programming "a proper chance" of at least six to twelve months before calling it quits? Could all my pains be growing pains, and will they magically disappear as I get more experienced? Or is gaining this perspective is valuable enough, even if plan to do more "backend stuff" later on, that it's worth grinding my teeth and continuing with my learning?

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• More on Map Testing

  - by Michael Stephenson

  I have been chatting with Maurice den Heijer recently about his codeplex project for the BizTalk Map Testing Framework (http://mtf.codeplex.com/). Some of you may remember the article I did for BizTalk 2009 and 2006 about how to test maps but with Maurice's project he is effectively looking at how to improve productivity and quality by building some useful testing features within the framework to simplify the process of testing maps. As part of our discussion we realized that we both had slightly different approaches to how we validate the output from the map. Put simple Maurice does some xpath validation of the data in various nodes where as my approach for most standard cases is to use serialization to allow you to validate the output using normal MSTest assertions. I'm not really going to go into the pro's and con's of each approach because I think there is a place for both and also I'm sure others have various approaches which work too. What would be great is for the map testing framework to provide support for different ways of testing which can cover everything from simple cases to some very specialized scenarios. So as agreed with Maurice I have done the sample which I will talk about in the rest of this article to show how we can use the serialization approach to create and compare the input and output from a map in normal development testing. Prerequisites One of the common patterns I usually implement when developing BizTalk solutions is to use xsd.exe to create .net classes for most of the schemas used within the solution. In the testing pattern I will take advantage of these .net classes. The Map In this sample the map we will use is very simple and just concatenates some data from the input message to the output message. Hopefully the below picture illustrates this well. The Test In the test I'm basically taking the following actions: Use the .net class generated from the schema to create an input message for the map Serialize the input object to a file Run the map from .net using the standard BizTalk test method which was generated for running the map Deserialize the output file from the map execution to a .net class representing the output schema Use MsTest assertions to validate things about the output message The below picture shows this: As you can see the code for this is pretty simple and it's all strongly typed which means changes to my schema which can affect the tests can be easily picked up as compilation errors. I can then chose to have one test which validates most of the output from the map, or to have many specific tests covering individual scenarios within the map. Summary Hopefully this post illustrates a powerful yet simple way of effectively testing many BizTalk mapping scenarios. I will probably have more conversations with Maurice about these approaches and perhaps some of the above will be included in the mapping test framework.   The sample can be downloaded from here: http://cid-983a58358c675769.office.live.com/self.aspx/Blog%20Samples/More%20Map%20Testing/MapTestSample.zip

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• C# Preprocessor Directives

  - by MarkPearl

  Going back to my old c++ days at university where we had all our code littered with preprocessor directives - I thought it made the code ugly and could never understand why it was useful. Today though I found a use in my C# application. The scenario – I had made various security levels in my application and tied my XAML to the levels by set by static accessors in code. An example of my XAML code for a Combobox to be enabled would be as follows… <ComboBox IsEnabled="{x:Static security:Security.SecurityCanEditDebtor}" />   And then I would have a static method like this… public static bool SecurityCanEditDebtorPostalAddress { get { if (SecurityCanEditDebtorPostalAddress) { return true; } else { return false; } } } My only problem was that my XAML did not like the if statement – which meant that while my code worked during runtime, during design time in VS2010 it gave some horrible error like… NullReferenceException was thrown on “StatiucExtension”: Exception has been thrown by the target of an invocation… If however my C# method was changed to something like this… public static bool SecurityCanEditDebtorPostalAddress { get { return true; } }   My XAML viewer would be happy. But of course this would bypass my security… <Drum Roll> Welcome preprocessor directives… what I wanted was during my design experience to totally remove the “if” code so that my accessor would return true and not have any if statements, but when I release my project to the big open world, I want the code to have the is statement. With a bit of searching I found the relevant MSDN sample and my code now looks like this… public static bool SecurityCanEditDebtorPostalAddress { get { #if DEBUG return true; #else if (Settings.GetInstance().CurrentUser.SecurityCanEditDebtorPostalAddress) { return true; } else { return false; } #endif } }   Not the prettiest beast, but it works. Basically what is being said here is that during my debug mode compile my code with just the code between the #if … #else block, but what I can now do is if I want to universally switch everything to the “if else” statement, I just go to my project properties –> Build and change the “Debug” flag as illustrated in the picture below. Also note that you can define your own conditional compilation symbols, and if you even wanted to you could skip the whole properties page and define them in code using the #define & #undef directives. So while I don’t like the way the code works and would like to look more into AOP and compare it to this method, it works for now.

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• Switch from back-end to front-end programming: I'm out of my comfort zone, should I switch back?

  - by ripper234

  I've been a backend developer for a long time, and I really swim in that field. C++/C#/Java, databases, NoSql, caching - I feel very much at ease around these platforms/concepts. In the past few years, I started to taste end-to-end web programming, and recently I decided to take a job offer in a front end team developing a large, complex product. I wanted to break out of my comfort zone and become more of an "all around developer". Problem is, I'm getting more and more convinced I don't like it. Things I like about backend programming, and missing in frontend stuff: More interesting problems - When I compare designing a server that handle massive data, to adding another form to a page or changing the validation logic, I find the former a lot more interesting. Refactoring refactoring refactoring - I am addicted to Visual Studio with Resharper, or IntelliJ. I feel very comfortable writing code as it goes without investing too much thought, because I know that with a few clicks I can refactor it into beautiful code. To my knowledge, this doesn't exist at all in javascript. Intellisense and navigation - I hate looking at a bunch of JS code without instantly being able to know what it does. In VS/IntelliJ I can summon the documentation, navigate to the code, climb up inheritance hiererchies ... life is sweet. Auto-completion - Just hit Ctrl-Space on an object to see what you can do with it. Easier to test - With almost any backend feature, I can use TDD to capture the requirements, see a bunch of failing tests, then implement, knowing that if the tests pass I did my job well. With frontend, while tests can help a bit, I find that most of the testing is still manual - fire up that browser and verify the site didn't break. I miss that feeling of "A green CI means everything is well with the world." Now, I've only seriously practiced frontend development for about two months now, so this might seem premature ... but I'm getting a nagging feeling that I should abandon this quest and return to my comfort zone, because, well, it's so comfy and fun. Another point worth mentioning in this context is that while I am learning some frontend tools, a lot of what I'm learning is our company's specific infrastructure, which I'm not sure will be very useful later on in my career. Any suggestions or tips? Do you think I should give frontend programming "a proper chance" of at least six to twelve months before calling it quits? Could all my pains be growing pains, and will they magically disappear as I get more experienced? Or is gaining this perspective is valuable enough, even if plan to do more "backend stuff" later on, that it's worth grinding my teeth and continuing with my learning?

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• 5.1 surround sound

  - by rocker9455

  Ok, So i've always had trouble with enabling 5.1 in ubuntu. Running 'alsamixer': I have: Master, Heaphones, PCM, Front, Front Mi, Front Mi, Surround, Center All are at 100% Card:HDA Intel Chip:Realtek ALC888 (This is my onboard sound, Its a dell studio, with 7.1 integrated sound) Running "speaker-test -c6 -twav" I only get the front 2 speakers (Right/Left) making any noise. The others make no noise at all. I have no other sound card to use as all my PCI slots are used up. Daemon.conf: ; daemonize = no ; fail = yes ; allow-module-loading = yes ; allow-exit = yes ; use-pid-file = yes ; system-instance = no ; enable-shm = yes ; shm-size-bytes = 0 # setting this 0 will use the system-default, usually 64 MiB ; lock-memory = no ; cpu-limit = no ; high-priority = yes ; nice-level = -11 ; realtime-scheduling = yes ; realtime-priority = 5 ; exit-idle-time = 20 ; scache-idle-time = 20 ; dl-search-path = (depends on architecture) ; load-default-script-file = yes ; default-script-file = ; log-target = auto ; log-level = notice ; log-meta = no ; log-time = no ; log-backtrace = 0 resample-method = speex-float-1 ; enable-remixing = yes ; enable-lfe-remixing = no flat-volumes = no ; rlimit-fsize = -1 ; rlimit-data = -1 ; rlimit-stack = -1 ; rlimit-core = -1 ; rlimit-as = -1 ; rlimit-rss = -1 ; rlimit-nproc = -1 ; rlimit-nofile = 256 ; rlimit-memlock = -1 ; rlimit-locks = -1 ; rlimit-sigpending = -1 ; rlimit-msgqueue = -1 ; rlimit-nice = 31 ; rlimit-rtprio = 9 ; rlimit-rttime = 1000000 ; default-sample-format = s16le ; default-sample-rate = 44100 ; default-sample-channels = 6 ; default-channel-map = front-left,front-right default-fragments = 8 default-fragment-size-msec = 10

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• Keeping your options open in a cloud solution

  - by BuckWoody

  In on-premises solutions we have the full range of options open for a given computing solution – but we don’t always take advantage of them, for multiple reasons. Data goes in a Relational Database Management System, files go on a share, and e-mail goes to the Exchange server. Over time, vendors (including ourselves) add in functionality to one product that allow non-standard use of the platform. For example, SQL Server (and Oracle, and others) allow large binary storage in or through the system – something not originally intended for an RDBMS to handle. There are certainly times when this makes sense, of course, but often these platform hammers turn every problem into a nail. It can make us “lazy” in our design – we sometimes don’t take the time to learn another architecture because the one we’ve spent so much time with can handle what we want to do. But there’s a distinct danger here. In nature, when a population shares too many of the same traits, it can cause a complete collapse if a situation exploits a weakness shared by that population. The same is true with not using the righttool for the job in a computing environment. Your company or organization depends on your knowledge as a professional to select the best mix of supportable, flexible, cost-effective technologies to solve their problems, whether you’re in an architect role or not.  So take some time today to learn something new. The way I do this is to select a given problem, and try to solve it with a technology I’m not familiar with. For instance – create a Purchase Order system in Excel, then in Hadoop or MongoDB, or even in flat-files using PowerShell as an interface. No, I’m not suggesting any of these architectures are the proper way to solve the PO problem, but taking something concrete that you know well and applying that meta-knowledge to another platform will assist you in exercising the “little grey cells” and help you and your organization understand what is open to you. And of course you can do all of this on-premises – but my recommendation is to check out a cloud platform (my suggestion would of course be Windows Azure :) ) and try it there. Most providers (including Microsoft) provide free time to do that.

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• Is there a factory pattern to prevent multiple instances for same object (instance that is Equal) good design?

  - by dsollen

  I have a number of objects storing state. There are essentially two types of fields. The ones that uniquely define what the object is (what node, what edge etc), and the others that store state describing how these things are connected (this node is connected to these edges, this edge is part of these paths) etc. My model is updating the state variables using package methods, so all these objects act as immutable to anyone not in Model scope. All Objects extend one base type. I've toyed with the idea of a Factory approach which accepts a Builder object and constructs the applicable object. However, if an instance of the object already exists (ie would return true if I created the object defined by the builder and passed it to the equal method for the existing instance) the factory returns the current object instead of creating a new instance. Because the Equal method would only compare what uniquely defines the type of object (this is node A to node B) but won't check the dynamic state stuff (node A is currently connected to nodes C and E) this would be a way of ensuring anyone that wants my Node A automatically knows its state connections. More importantly it would prevent aliasing nightmares of someone trying to pass an instance of node A with different state then the node A in my model has. I've never heard of this pattern before, and it's a bit odd. I would have to do some overriding of serialization methods to make it work (ensure that when I read in a serilized object I add it to my facotry list of known instances, and/or return an existing factory in its place), as well as using a weakHashMap as if it was a weakHashSet to know whether an instance exists without worrying about a quasi-memory leak occuring. I don't know if this is too confusing or prone to its own obscure bugs. One thing I know is that plugins interface with lowest level hardware. The plugins have to be able to return state that is different than my memory; to tell my memory when its own state is inconsistent. I believe this is possible despite their fetching objects that exist in my memory; we allow building of objects without checking their consistency with the model until the addToModel is called anyways; and the existing plugins design was written before all this extra state existed and worked fine without ever being aware of it. Should I just be using some other design to avoid this crazyness? (I have another question to that affect that I'm posting).

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• How to avoid oscillation by async event based systems?

  - by inf3rno

  Imagine a system where there are data sources which need to be kept in sync. A simple example is model - view data binding by MVC. Now I intend to describe these kind of systems with data sources and hubs. Data sources are publishing and subscribing for events and hubs are relaying events to data sources. By handling an event a data source will change it state described in the event. By publishing an event the data source puts its current state to the event, so other data sources can use that information to change their state accordingly. The only problem with this system, that events can be reflected from the hub or from the other data sources, and that can put the system into an infinite oscillation (by async or infinite loop by sync). For example A -- data source B -- data source H -- hub A -> H -> A -- reflection from the hub A -> H -> B -> H -> A -- reflection from another data source By sync it is relatively easy to solve this issue. You can compare the current state with the event, and if they are equal, you don't change the state and raise the same event again. By async I could not find a solution yet. The state comparison does not work by async event handling because there is eventual consistency, and new events can be published in an inconsistent state causing the same oscillation. For example: A(*->x) -> H -> B(y->x) -- can go parallel with B(*->y) -> H -> A(x->y) -- so first A changes to x state while B changes to y state -- then B changes to x state while A changes to y state -- and so on for eternity... What do you think is there an algorithm to solve this problem? If there is a solution, is it possible to extend it to prevent oscillation caused by multiple hubs, multiple different events, etc... ? update: I don't think I can make this work without a lot of effort. I think this problem is just the same as we have by syncing multiple databases in a distributed system. So I think what I really need is constraints if I want to prevent this problem in an automatic way. What constraints do you suggest?

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