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  • Reg Gets a Job at Red Gate (and what happens behind the scenes)

    - by red(at)work
    Mr Reg Gater works at one of Cambridge’s many high-tech companies. He doesn’t love his job, but he puts up with it because... well, it could be worse. Every day he drives to work around the Red Gate roundabout, wondering what his boss is going to blame him for today, and wondering if there could be a better job out there for him. By late morning he already feels like handing his notice in. He got the hacky look from his boss for being 5 minutes late, and then they ran out of tea. Again. He goes to the local sandwich shop for lunch, and picks up a Red Gate job menu and a Book of Red Gate while he’s waiting for his order. That night, he goes along to Cambridge Geek Nights and sees some very enthusiastic Red Gaters talking about the work they do; it sounds interesting and, of all things, fun. He takes a quick look at the job vacancies on the Red Gate website, and an hour later realises he’s still there – looking at videos, photos and people profiles. He especially likes the Red Gate’s Got Talent page, and is very impressed with Simon Johnson’s marathon time. He thinks that he’d quite like to work with such awesome people. It just so happens that Red Gate recently decided that they wanted to hire another hot shot team member. Behind the scenes, the wheels were set in motion: the recruitment team met with the hiring manager to understand exactly what they’re looking for, and to decide what interview tests to do, who will do the interviews, and to kick-start any interview training those people might need. Next up, a job description and job advert were written, and the job was put on the market. Reg applies, and his CV lands in the Recruitment team’s inbox and they open it up with eager anticipation that Reg could be the next awesome new starter. He looks good, and in a jiffy they’ve arranged an interview. Reg arrives for his interview, and is greeted by a smiley receptionist. She offers him a selection of drinks and he feels instantly relaxed. A couple of interviews and an assessment later, he gets a job offer. We make his day and he makes ours by accepting, and becoming one of the 60 new starters so far this year. Behind the scenes, things start moving all over again. The HR team arranges for a “Welcome” goodie box to be whisked out to him, prepares his contract, sends an email to Information Services (Or IS for short - we’ll come back to them), keeps in touch with Reg to make sure he knows what to expect on his first day, and of course asks him to fill in the all-important wiki questionnaire so his new colleagues can start to get to know him before he even joins. Meanwhile, the IS team see an email in SupportWorks from HR. They see that Reg will be starting in the sales team in a few days’ time, and they know exactly what to do. They pull out a new machine, and within minutes have used their automated deployment software to install every piece of software that a new recruit could ever need. They also check with Reg’s new manager to see if he has any special requirements that they could help with. Reg starts and is amazed to find a fully configured machine sitting on his desk, complete with stationery and all the other tools he’ll need to do his job. He feels even more cared for after he gets a workstation assessment, and realises he’d be comfier with an ergonomic keyboard and a footstool. They arrive minutes later, just like that. His manager starts him off on his induction and sales training. Along with job-specific training, he’ll also have a buddy to help him find his feet, and loads of pre-arranged demos and introductions. Reg settles in nicely, and is great at his job. He enjoys the canteen, and regularly eats one of the 40,000 meals provided each year. He gets used to the selection of teas that are available, develops a taste for champagne launch parties, and has his fair share of the 25,000 cups of coffee downed at Red Gate towers each year. He goes along to some Feel Good Fund events, and donates a little something to charity in exchange for a turn on the chocolate fountain. He’s looking a little scruffy, so he decides to get his hair cut in between meetings, just in time for the Red Gate birthday company photo. Reg starts a new project: identifying existing customers to up-sell to new bundles. He talks with the web team to generate lists of qualifying customers who haven’t recently been sent marketing emails, and sends emails out, using a new in-house developed tool to schedule follow-up calls in CRM for the same group. The customer responds, saying they’d like to upgrade but are having a licensing problem – Reg sends the issue to Support, and it gets routed to the web team. The team identifies a workaround, and the bug gets scheduled into the next maintenance release in a fortnight’s time (hey; they got lucky). With all the new stuff Reg is working on, he realises that he’d be way more efficient if he had a third monitor. He speaks to IS and they get him one - no argument. He also needs a test machine and then some extra memory. Done. He then thinks he needs an iPad, and goes to ask for one. He gets told to stop pushing his luck. Some time later, Reg’s wife has a baby, so Reg gets 2 weeks of paid paternity leave and a bunch of flowers sent to his house. He signs up to the childcare scheme so that he doesn’t have to pay National Insurance on the first £243 of his childcare. The accounts team makes it all happen seamlessly, as they did with his Give As You Earn payments, which come out of his wages and go straight to his favorite charity. Reg’s sales career is going well. He’s grateful for the help that he gets from the product support team. How do they answer all those 900-ish support calls so effortlessly each month? He’s impressed with the patches that are sent out to customers who find “interesting behavior” in their tools, and to the customers who just must have that new feature. A little later in his career at Red Gate, Reg decides that he’d like to learn about management. He goes on some management training specially customised for Red Gate, joins the Management Book Club, and gets together with other new managers to brainstorm how to get the most out of one to one meetings with his team. Reg decides to go for a game of Foosball to celebrate his good fortune with his team, and has to wait for Finance to finish. While he’s waiting, he reflects on the wonderful time he’s had at Red Gate. He can’t put his finger on what it is exactly, but he knows he’s on to a good thing. All of the stuff that happened to Reg didn’t just happen magically. We’ve got teams of people working relentlessly behind the scenes to make sure that everyone here is comfortable, safe, well fed and caffeinated to the max.

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  • Columnstore Case Study #2: Columnstore faster than SSAS Cube at DevCon Security

    - by aspiringgeek
    Preamble This is the second in a series of posts documenting big wins encountered using columnstore indexes in SQL Server 2012 & 2014.  Many of these can be found in my big deck along with details such as internals, best practices, caveats, etc.  The purpose of sharing the case studies in this context is to provide an easy-to-consume quick-reference alternative. See also Columnstore Case Study #1: MSIT SONAR Aggregations Why Columnstore? As stated previously, If we’re looking for a subset of columns from one or a few rows, given the right indexes, SQL Server can do a superlative job of providing an answer. If we’re asking a question which by design needs to hit lots of rows—DW, reporting, aggregations, grouping, scans, etc., SQL Server has never had a good mechanism—until columnstore. Columnstore indexes were introduced in SQL Server 2012. However, they're still largely unknown. Some adoption blockers existed; yet columnstore was nonetheless a game changer for many apps.  In SQL Server 2014, potential blockers have been largely removed & they're going to profoundly change the way we interact with our data.  The purpose of this series is to share the performance benefits of columnstore & documenting columnstore is a compelling reason to upgrade to SQL Server 2014. The Customer DevCon Security provides home & business security services & has been in business for 135 years. I met DevCon personnel while speaking to the Utah County SQL User Group on 20 February 2012. (Thanks to TJ Belt (b|@tjaybelt) & Ben Miller (b|@DBADuck) for the invitation which serendipitously coincided with the height of ski season.) The App: DevCon Security Reporting: Optimized & Ad Hoc Queries DevCon users interrogate a SQL Server 2012 Analysis Services cube via SSRS. In addition, the SQL Server 2012 relational back end is the target of ad hoc queries; this DW back end is refreshed nightly during a brief maintenance window via conventional table partition switching. SSRS, SSAS, & MDX Conventional relational structures were unable to provide adequate performance for user interaction for the SSRS reports. An SSAS solution was implemented requiring personnel to ramp up technically, including learning enough MDX to satisfy requirements. Ad Hoc Queries Even though the fact table is relatively small—only 22 million rows & 33GB—the table was a typical DW table in terms of its width: 137 columns, any of which could be the target of ad hoc interrogation. As is common in DW reporting scenarios such as this, it is often nearly to optimize for such queries using conventional indexing. DevCon DBAs & developers attended PASS 2012 & were introduced to the marvels of columnstore in a session presented by Klaus Aschenbrenner (b|@Aschenbrenner) The Details Classic vs. columnstore before-&-after metrics are impressive. Scenario   Conventional Structures   Columnstore   Δ SSRS via SSAS 10 - 12 seconds 1 second >10x Ad Hoc 5-7 minutes (300 - 420 seconds) 1 - 2 seconds >100x Here are two charts characterizing this data graphically.  The first is a linear representation of Report Duration (in seconds) for Conventional Structures vs. Columnstore Indexes.  As is so often the case when we chart such significant deltas, the linear scale doesn’t expose some the dramatically improved values corresponding to the columnstore metrics.  Just to make it fair here’s the same data represented logarithmically; yet even here the values corresponding to 1 –2 seconds aren’t visible.  The Wins Performance: Even prior to columnstore implementation, at 10 - 12 seconds canned report performance against the SSAS cube was tolerable. Yet the 1 second performance afterward is clearly better. As significant as that is, imagine the user experience re: ad hoc interrogation. The difference between several minutes vs. one or two seconds is a game changer, literally changing the way users interact with their data—no mental context switching, no wondering when the results will appear, no preoccupation with the spinning mind-numbing hurry-up-&-wait indicators.  As we’ve commonly found elsewhere, columnstore indexes here provided performance improvements of one, two, or more orders of magnitude. Simplified Infrastructure: Because in this case a nonclustered columnstore index on a conventional DW table was faster than an Analysis Services cube, the entire SSAS infrastructure was rendered superfluous & was retired. PASS Rocks: Once again, the value of attending PASS is proven out. The trip to Charlotte combined with eager & enquiring minds let directly to this success story. Find out more about the next PASS Summit here, hosted this year in Seattle on November 4 - 7, 2014. DevCon BI Team Lead Nathan Allan provided this unsolicited feedback: “What we found was pretty awesome. It has been a game changer for us in terms of the flexibility we can offer people that would like to get to the data in different ways.” Summary For DW, reports, & other BI workloads, columnstore often provides significant performance enhancements relative to conventional indexing.  I have documented here, the second in a series of reports on columnstore implementations, results from DevCon Security, a live customer production app for which performance increased by factors of from 10x to 100x for all report queries, including canned queries as well as reducing time for results for ad hoc queries from 5 - 7 minutes to 1 - 2 seconds. As a result of columnstore performance, the customer retired their SSAS infrastructure. I invite you to consider leveraging columnstore in your own environment. Let me know if you have any questions.

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  • What's new in Solaris 11.1?

    - by Karoly Vegh
    Solaris 11.1 is released. This is the first release update since Solaris 11 11/11, the versioning has been changed from MM/YY style to 11.1 highlighting that this is Solaris 11 Update 1.  Solaris 11 itself has been great. What's new in Solaris 11.1? Allow me to pick some new features from the What's New PDF that can be found in the official Oracle Solaris 11.1 Documentation. The updates are very numerous, I really can't include all.  I. New AI Automated Installer RBAC profiles have been introduced to enable delegation of installation tasks. II. The interactive installer now supports installing the OS to iSCSI targets. III. ASR (Auto Service Request) and OCM (Oracle Configuration Manager) have been enabled by default to proactively provide support information and create service requests to speed up support processes. This is optional and can be disabled but helps a lot in supportcases. For further information, see: http://oracle.com/goto/solarisautoreg IV. The new command svcbundle helps you to create SMF manifests without having to struggle with XML editing. (btw, do you know the interactive editprop subcommand in svccfg? The listprop/setprop subcommands are great for scripting and automating, but for an interactive property editing session try, for example, this: svccfg -s svc:/application/pkg/system-repository:default editprop )  V. pfedit: Ever wondered how to delegate editing permissions to certain files? It is well known "sudo /usr/bin/vi /etc/hosts" is not the right way, for sudo elevates the complete vi process to admin levels, and the user can "break" out of the session as root with simply starting a shell from that vi. Now, the new pfedit command provides a solution exactly to this challenge - an auditable, secure, per-user configurable editing possibility. See the pfedit man page for examples.   VI. rsyslog, the popular logging daemon (filters, SSL, formattable output, SQL collect...) has been included in Solaris 11.1 as an alternative to syslog.  VII: Zones: Solaris Zones - as a major Solaris differentiator - got lots of love in terms of new features: ZOSS - Zones on Shared Storage: Placing your zones to shared storage (FC, iSCSI) has never been this easy - via zonecfg.  parallell updates - with S11's bootenvironments updating zones was no problem and meant no downtime anyway, but still, now you can update them parallelly, a way faster update action if you are running a large number of zones. This is like parallell patching in Solaris 10, but with all the IPS/ZFS/S11 goodness.  per-zone fstype statistics: Running zones on a shared filesystems complicate the I/O debugging, since ZFS collects all the random writes and delivers them sequentially to boost performance. Now, over kstat you can find out which zone's I/O has an impact on the other ones, see the examples in the documentation: http://docs.oracle.com/cd/E26502_01/html/E29024/gmheh.html#scrolltoc Zones got RDSv3 protocol support for InfiniBand, and IPoIB support with Crossbow's anet (automatic vnic creation) feature.  NUMA I/O support for Zones: customers can now determine the NUMA I/O topology of the system from within zones.  VIII: Security got a lot of attention too:  Automated security/audit reporting, with builtin reporting templates e.g. for PCI (payment card industry) audits.  PAM is now configureable on a per-user basis instead of system wide, allowing different authentication requirements for different users  SSH in Solaris 11.1 now supports running in FIPS 140-2 mode, that is, in a U.S. government security accredited fashion.  SHA512/224 and SHA512/256 cryptographic hash functions are implemented in a FIPS-compliant way - and on a T4 implemented in silicon! That is, goverment-approved cryptography at HW-speed.  Generally, Solaris is currently under evaluation to be both FIPS and Common Criteria certified.  IX. Networking, as one of the core strengths of Solaris 11, has been extended with:  Data Center Bridging (DCB) - not only setups where network and storage share the same fabric (FCoE, anyone?) can have Quality-of-Service requirements. DCB enables peers to distinguish traffic based on priorities. Your NICs have to support DCB, see the documentation, and additional information on Wikipedia. DataLink MultiPathing, DLMP, enables link aggregation to span across multiple switches, even between those of different vendors. But there are essential differences to the good old bandwidth-aggregating LACP, see the documentation: http://docs.oracle.com/cd/E26502_01/html/E28993/gmdlu.html#scrolltoc VNIC live migration is now supported from one physical NIC to another on-the-fly  X. Data management:  FedFS, (Federated FileSystem) is new, it relies on Solaris 11's NFS referring mechanism to join separate shares of different NFS servers into a single filesystem namespace. The referring system has been there since S11 11/11, in Solaris 11.1 FedFS uses a LDAP - as the one global nameservice to bind them all.  The iSCSI initiator now uses the T4 CPU's HW-implemented CRC32 algorithm - thus improving iSCSI throughput while reducing CPU utilization on a T4 Storage locking improvements are now RAC aware, speeding up throughput with better locking-communication between nodes up to 20%!  XI: Kernel performance optimizations: The new Virtual Memory subsystem ("VM2") scales now to 100+ TB Memory ranges.  The memory predictor monitors large memory page usage, and adjust memory page sizes to applications' needs OSM, the Optimized Shared Memory allows Oracle DBs' SGA to be resized online XII: The Power Aware Dispatcher in now by default enabled, reducing power consumption of idle CPUs. Also, the LDoms' Power Management policies and the poweradm settings in Solaris 11 OS will cooperate. XIII: x86 boot: upgrade to the (Grand Unified Bootloader) GRUB2. Because grub2 differs in the configuration syntactically from grub1, one shall not edit the new grub configuration (grub.cfg) but use the new bootadm features to update it. GRUB2 adds UEFI support and also support for disks over 2TB. XIV: Improved viewing of per-CPU statistics of mpstat. This one might seem of less importance at first, but nowadays having better sorting/filtering possibilities on a periodically updated mpstat output of 256+ vCPUs can be a blessing. XV: Support for Solaris Cluster 4.1: The What's New document doesn't actually mention this one, since OSC 4.1 has not been released at the time 11.1 was. But since then it is available, and it requires Solaris 11.1. And it's only a "pkg update" away. ...aand I seriously need to stop here. There's a lot I missed, Edge Virtual Bridging, lofi tuning, ZFS sharing and crypto enhancements, USB3.0, pulseaudio, trusted extensions updates, etc - but if I mention all those then I effectively copy the What's New document. Which I recommend reading now anyway, it is a great extract of the 300+ new projects and RFE-followups in S11.1. And this blogpost is a summary of that extract.  For closing words, allow me to come back to Request For Enhancements, RFEs. Any customer can request features. Open up a Support Request, explain that this is an RFE, describe the feature you/your company desires to have in S11 implemented. The more SRs are collected for an RFE, the more chance it's got to get implemented. Feel free to provide feedback about the product, as well as about the Solaris 11.1 Documentation using the "Feedback" button there. Both the Solaris engineers and the documentation writers are eager to hear your input.Feel free to comment about this post too. Except that it's too long ;)  wbr,charlie

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  • Communities - The importance of exchange and discussion

    Communication with your environment is an essential part of everyone's life. And it doesn't matter whether you are actually living in a rural area in the middle of nowhere, within the pulsating heart of a big city, or in my case on a wonderful island in the Indian Ocean. The ability to exchange your thoughts, your experience and your worries with another person helps you to get different points of view and new ideas on how to resolve an issue you might be confronted with. Benefits of community work What happens to be common sense in your daily life, also applies to your work environment. Working in IT, or ICT as it is called in Mauritius, requires a lot of reading and learning. Not only during your lectures at the university but with your colleagues in a project assignment and hopefully with 'unknown' pals in the universe of online communities. At least I can say that I learned quite a lot from other developers code, their responses in various forums, their numerous blog articles, and while attending local user group meetings. When I started to work as a professional software developer (or engineer some may say) years ago I immediately checked the existence of communities on the programming language, the database technology and other vital information on software development in general. Luckily, it wasn't too difficult to find. My employer had a subscription of the monthly magazines and newsletters of a national organisation which also run the biggest forum in that area. Getting in touch with other developers and reading their common problems but also solutions was a huge benefit to my growth. Image courtesy of Michael Kappel (CC BY-NC 2.0) Active participation and regular contribution to this community gave me some nice advantages, too. Within three years I was listed as a conference speaker at the annual developer's conference and provided several sessions on different topics during consecutive years. Back in 2004, I took over the responsibility and management of the monthly meetings of a regional user group, and organised it for more than two years. Furthermore, I was invited to the newly-founded community program of Microsoft Germany (Community Leader/Insider Program - CLIP). My website on Active FoxPro Pages was nominated in the second batch of online communities. Due to my community work and providing advice to others, I had the honour to be awarded as Microsoft Most Valuable Professional (MVP) - Visual Developer for Visual FoxPro in the years 2006 and 2007. It was a great experience to meet with other like-minded people and I'm really grateful for that. Just in case, more details are listed in my Curriculum Vitae. But this all changed when I moved to Mauritius... Cyber island Mauritius? During the first months in Mauritius I was way too busy to think about community activities at all. First of all, there was the new company that had to be set up, the new staff had to be trained and of course the communication work-flows and so on with the project managers back in Germany had to be sorted out, too. Second, I had to get a grip of my private matters like getting the basics for my new household or exploring the neighbourhood, and last but not least I needed a break from the hectic and intensive work prior to my departure. As soon as the sea literally calmed down, I started to have conversations with my colleagues about communities and user groups. Sadly, it turned out that there were none, or at least no one was aware of any at that time. Oh oh, what did I do? Anyway, having this kind of background and very positive experience with off-line and on-line activities I decided for myself that some day I'm going to found a community in Mauritius for all kind of IT/ICT-related fields. The main focus might be on software development but not on a certain technology or methodology. It was clear to me that it should be an open infrastructure and anyone is welcome to join, to experience, to share and to contribute if they would like to. That was the idea at that time... Ok, fast-forward to recent events. At the end of October 2012 I was invited to an event called Open Days organised by Microsoft Indian Ocean Islands together with other local partners and resellers. There I got in touch with local Technical Evangelist Arnaud Meslier and we had a good conversation on communities during the breaks. Eventually, I left a good impression on him, as we are having chats on Facebook or Skype irregularly. Well, seeing that my personal and professional surroundings have been settled and running smooth, having that great exchange and contact with Microsoft IOI (again), and being really eager to re-animate my intentions from 2007, I recently founded a new community: Mauritius Software Craftsmanship Community - #MSCC It took me a while to settle down with the name but it was obvious that the community should not be attached to one single technology, like ie. .NET user group, Oracle developers, or Joomla friends (these are fictitious names). There are several other reasons why I came up with 'Craftsmanship' as the core topic of this community. The expression of 'engineering' didn't feel right with the fields covered. Software development in all kind of facets is a craft, and therefore demands a lot of practice but also guidance from more experienced developers. It also includes the process of designing, modelling and drafting the ideas. Has to deal with various types of tests and test methodologies, and of course should be focused on flexible and agile ways of acting. In order to meet and to excel a customer's request for a solution. Next, I was looking for an easy way to handle the organisation of events and meeting appointments. Using all kind of social media platforms like Google+, LinkedIn, Facebook, Xing, etc. I was never really confident about their features of event handling. More by chance I stumbled upon Meetup.com and in combination with the other entities (G+ Communities, FB Pages or in Groups) I am looking forward to advertise and manage all future activities here: Mauritius Software Craftsmanship Community This is a community for those who care and are proud of what they do. For those developers, regardless how experienced they are, who want to improve and master their craft. This is a community for those who believe that being average is just not good enough. I know, there are not many 'craftsmen' yet but it's a start... Let's see how it looks like by the end of the year. There are free smartphone apps for Android and iOS from Meetup.com that allow you to keep track of meetings and to stay informed on latest updates. And last but not least, there will be a Trello workspace to collect and share ideas and provide downloads of slides, etc. Sharing is caring! As mentioned, the #MSCC is present in various social media networks in order to cover as many people as possible here in Mauritius. Following is an overview of the current networks: Twitter - Latest updates and quickies Google+ - Community channel Facebook - Community Page LinkedIn - Community Group Trello - Collaboration workspace to share and develop ideas Hopefully, this covers the majority of computer-related people in Mauritius. Please spread the word about the #MSCC between your colleagues, your friends and other interested 'geeks'. Your future looks bright Running and participating in a user group or any kind of community usually provides quite a number of advantages for anyone. On the one side it is very joyful for me to organise appointments and get in touch with people that might be interested to present a little demo of their projects or their recent problems they had to tackle down, and on the other side there are lots of companies that have various support programs or sponsorships especially tailored for user groups. At the moment, I already have a couple of gimmicks that I would like to hand out in small contests or raffles during one of the upcoming meetings, and as said, companies provide all kind of goodies, books free of charge, or sometimes even licenses for communities. Meeting other software developers or IT guys also opens up your point of view on the local market and there might be interesting projects or job offers available, too. A community like the Mauritius Software Craftsmanship Community is great for freelancers, self-employed, students and of course employees. Meetings will be organised on a regular basis, and I'm open to all kind of suggestions from you. Please leave a comment here in blog or join the conversations in the above mentioned social networks. Let's get this community up and running, my fellow Mauritians!

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  • Trac vs. Redmine vs. JIRA vs. FogBugz for one-man shop?

    - by kizzx2
    Background I am a one-man freelancer looking for a project management software that can provide the following requirements. I have used Trac for about a year now. Tried Redmine and FogBugz on Demand for a couple of weeks. Never tried JIRA before. Basically, I'm looking for a piece of software that: Facilitates developer-client communication/collaboration Does time tracking Requirements Record time estimates/Time tracking Clients must be able to create/edit his own tickets/cases Clients must not see Developer created tickets/cases (internal) Affordable (price) with multiple clients Nice-to-haves Supports multiple projects in one installation Free eclipse integration (Mylyn) Easy time-tracking without using the Web UI (Trac's post commit hook or Redmine's commit message scanning) Clients can access the Wiki Export the data to standard formats My evaluation Trac can basically fulfill most of the above requirements, but with lots of customizations and plug-ins that it doesn't feel so clean. One downside is that the main trunk (0.11) has been around for a year or more and I still haven't seen much tendency of any upgrades coming up. Redmine has the cleanest Web UI. It's design philosophy seems to be the most elegant, with its innovative commit message scanning and stuff. However, the current version doesn't seem to be very mature and stable yet. It doesn't support internal (private) tickets and the time-tracking commit message patch doesn't support the trunk version. The good thing about it is that the main trunk still seems to be actively developed. FogBugz is actually a very well written piece of software. However the idea of paying $25/month for the client to be able to log-in to the system seems a little bit too far off for an individual developer. The free version supports letting clients create/view their own cases using email, which is a sub-optimal alternative to having a full-fledged list of the user's own cases. That also means clients can't read/write wiki pages. Its time-tracking approach is innovative and good though. However the fact that all the eclipse integration (Bugclipse, Foglyn) are commercial. Yet other investments before I can use my bug-tracker! If I revert back to the Web UI, it's not really a fast rendering Web service. Also, the in-built report functions are excellent (e.g. evidence based scheduling) JIRA is something I have zero experience with. Can someone with JIRA experience recommend why it might be a good fit for this particular situation? Question Can we share experience on this? Any specific plugins/customizations would that would best suit the requirements for this case?

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  • WPF CommandParameter is NULL first time CanExecute is called

    - by Jonas Follesø
    I have run into an issue with WPF and Commands that are bound to a Button inside the DataTemplate of an ItemsControl. The scenario is quite straight forward. The ItemsControl is bound to a list of objects, and I want to be able to remove each object in the list by clicking a Button. The Button executes a Command, and the Command takes care of the deletion. The CommandParameter is bound to the Object I want to delete. That way I know what the user clicked. A user should only be able to delete their "own" objects - so I need to do some checks in the "CanExecute" call of the Command to verify that the user has the right permissions. The problem is that the parameter passed to CanExecute is NULL the first time it's called - so I can't run the logic to enable/disable the command. However, if I make it allways enabled, and then click the button to execute the command, the CommandParameter is passed in correctly. So that means that the binding against the CommandParameter is working. The XAML for the ItemsControl and the DataTemplate looks like this: <ItemsControl x:Name="commentsList" ItemsSource="{Binding Path=SharedDataItemPM.Comments}" Width="Auto" Height="Auto"> <ItemsControl.ItemTemplate> <DataTemplate> <StackPanel Orientation="Horizontal"> <Button Content="Delete" FontSize="10" Command="{Binding Path=DataContext.DeleteCommentCommand, ElementName=commentsList}" CommandParameter="{Binding}" /> </StackPanel> </DataTemplate> </ItemsControl.ItemTemplate> </ItemsControl> So as you can see I have a list of Comments objects. I want the CommandParameter of the DeleteCommentCommand to be bound to the Command object. So I guess my question is: have anyone experienced this problem before? CanExecute gets called on my Command, but the parameter is always NULL the first time - why is that? Update: I was able to narrow the problem down a little. I added an empty Debug ValueConverter so that I could output a message when the CommandParameter is data bound. Turns out the problem is that the CanExecute method is executed before the CommandParameter is bound to the button. I have tried to set the CommandParameter before the Command (like suggested) - but it still doesn't work. Any tips on how to control it. Update2: Is there any way to detect when the binding is "done", so that I can force re-evaluation of the command? Also - is it a problem that I have multiple Buttons (one for each item in the ItemsControl) that bind to the same instance of a Command-object? Update3: I have uploaded a reproduction of the bug to my SkyDrive: http://cid-1a08c11c407c0d8e.skydrive.live.com/self.aspx/Code%20samples/CommandParameterBinding.zip

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  • How can I make a WPF TreeView data binding lazy and asynchronous?

    - by pauldoo
    I am learning how to use data binding in WPF for a TreeView. I am procedurally creating the Binding object, setting Source, Path, and Converter properties to point to my own classes. I can even go as far as setting IsAsync and I can see the GUI update asynchronously when I explore the tree. So far so good! My problem is that WPF eagerly evaluates parts of the tree prior to them being expanded in the GUI. If left long enough this would result in the entire tree being evaluated (well actually in this example my tree is infinite, but you get the idea). I would like the tree only be evaluated on demand as the user expands the nodes. Is this possible using the existing asynchronous data binding stuff in the WPF? As an aside I have not figured out how ObjectDataProvider relates to this task. My XAML code contains only a single TreeView object, and my C# code is: public partial class Window1 : Window { public Window1() { InitializeComponent(); treeView.Items.Add( CreateItem(2) ); } static TreeViewItem CreateItem(int number) { TreeViewItem item = new TreeViewItem(); item.Header = number; Binding b = new Binding(); b.Converter = new MyConverter(); b.Source = new MyDataProvider(number); b.Path = new PropertyPath("Value"); b.IsAsync = true; item.SetBinding(TreeView.ItemsSourceProperty, b); return item; } class MyDataProvider { readonly int m_value; public MyDataProvider(int value) { m_value = value; } public int[] Value { get { // Sleep to mimick a costly operation that should not hang the UI System.Threading.Thread.Sleep(2000); System.Diagnostics.Debug.Write(string.Format("Evaluated for {0}\n", m_value)); return new int[] { m_value * 2, m_value + 1, }; } } } class MyConverter : IValueConverter { public object Convert(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture) { // Convert the double to an int. int[] values = (int[])value; IList<TreeViewItem> result = new List<TreeViewItem>(); foreach (int i in values) { result.Add(CreateItem(i)); } return result; } public object ConvertBack(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture) { throw new InvalidOperationException("Not implemented."); } } } Note: I have previously managed to do lazy evaluation of the tree nodes by adding WPF event handlers and directly adding items when the event handlers are triggered. I'm trying to move away from that and use data binding instead (which I understand is more in spirit with "the WPF way").

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  • T-SQL selecting values that match ISNUMERIC and also are within a specified range. (plus Linq-to-sql

    - by Toby
    I am trying to select rows from a table where one of the (NVARCHAR) columns is within a numeric range. SELECT ID, Value FROM Data WHERE ISNUMERIC(Value) = 1 AND CONVERT(FLOAT, Value) < 66.6 Unfortunately as part of the SQL spec the AND clauses don't have to short circuit (and don't on MSSQL Server EE 2008). More info: http://stackoverflow.com/questions/789231/is-the-sql-where-clause-short-circuit-evaluated My next attempt was to try this to see if I could achieve delayed evaluation of the CONVERT SELECT ID, Value FROM Data WHERE (CASE WHEN ISNUMERIC(Value) = 1 THEN CONVERT(FLOAT, Value) < 66.6 ELSE 0 END) but I cannot seem to use a < (or any comparison) with the result of a CONVERT. It fails with the error Incorrect syntax near '<'. I can get away with SELECT ID, CONVERT(FLOAT, Value) AS Value FROM Data WHERE ISNUMERIC(Value) = 1 So the obvious solution is to wrap the whole select statement in another SELECT and WHERE and return the converted values from the inner select and filter in there where of the outer select. Unfortunately this is where my Linq-to-sql problem comes in. I am filtering not only by one range but potentialy by many, or just by the existance of the record (there are some date range selects and comparisons I've left out.) Essentially I would like to be able to generate something like this: SELECT ID, TypeID, Value FROM Data WHERE (TypeID = 4 AND ISNUMERIC(Value) AND CONVERT(Float, Value) < 66.6) OR (TypeID = 8 AND ISNUMERIC(Value) AND CONVERT(Float, Value) > 99) OR (TypeID = 9) (With some other clauses in each of those where options.) This clearly doesn't work if I filter out the non-ISNUMERIC values in an inner select. As I mentioned I am using Linq-to-sql (and PredicateBulider) to build up these queries but unfortunately Datas.Where(x => ISNUMERIC(x.Value) ? Convert.ToDouble(x.Value) < 66.6 : false) Gets converted to this which fails the initial problem. WHERE (ISNUMERIC([t0].[Value]) = 1) AND ((CONVERT(Float,[t0].[Value])) < @p0) My last resort will have to be to outer join against a double select on the same table for each of the comparisons but this isn't really an idea solution. I was wondering if anyone has run into similar issues before?

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  • Featureful commercial text editors?

    - by wrp
    I'm willing to buy tools if they add genuine value over a FOSS equivalent. One thing I wouldn't mind having is an editor with the power of Emacs, but made more user-friendly. There seem to be several commercial editors out there, but I can't find much discussion of them online. Maybe it's because the kind of people who use commercial software don't have time to do much blogging. ;-) If you have used any, what was your evaluation? I'd especially like to hear how you would compare them to Emacs. I'm thinking of editors like VEDIT, Boxer, Crisp, UltraEdit, SlickEdit, etc. To get things started, I tried EditPad Pro because I needed something on a Win98SE box. I was attracted by its powerful support for regexps, but I didn't use it for long. One annoyance was that find-in-files was only available in a separate product you had to buy. The main problem, though, was stability. It sometimes hung and I lost a few files because it corrupted them while editing. After a couple weeks, I found that I was avoiding using it, so I just uninstalled. Edit: Ah...I need to remove some ambiguity. With reference to Emacs, "power" often means its potential for customization. This malleability comes from having an architecture in which most of the functionality is written in a scripting language that runs on a compiled core. Emacs (with elisp) is by far the most widely known such system among home users, but there have been other heavily used editors such as Freemacs (MINT), JED (S-Lang), XEDIT (Rexx), ADAM (TPU), and SlickEdit (Slick-C). In this case, by "power" I'm not referring to extensibility but to realized features. There are three main areas which I think a commercial text editor might be an improvement over Emacs: Stability The only apps I regularly use on Linux that give me flaky behavior are Emacs, Gedit, and Geany. On Windows, I like the look and features of Notepad++, but I find it extremely unstable, especially if I try to use the plugins. Whatever I happen to be doing, I'm using some text editor practically all day long. If I could switch to an editor that never gave me problems, it would definitely lower my stress level. Tools When I started using Emacs, I searched the manual cover to cover to gleam ideas for clever, useful things I could do with it. I'd like to see lots of useful features for editing code, based on detailed knowledge of what the system can do and the accumulated feedback of users. Polish The rule of threes goes that if you develop something for yourself, it's three times harder to make it usable in-house, and three times harder again to make it a viable product for sale. It's understandable, but free software development doesn't seem to benefit from much usability testing. BTW, texteditors.org is a fantastic resource for researching text editors.

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  • ASP.NET MVC3 Custom Membership Provider - The membership provider name specified is invalid.

    - by David Lively
    I'm implementing a custom membership provider, and everything seems to go swimmingly until I create a MembershipUser object. At that point, I receive the error: The membership provider name specified is invalid. Parameter name: providerName In web.config the membership key is <membership defaultProvider="MembersProvider"> <providers> <clear/> <add name="MembersProvider" type="Members.Providers.MembersProvider" connectionStringName="ApplicationServices" enablePasswordRetrieval="false" enablePasswordReset="true" requiresQuestionAndAnswer="false" requiresUniqueEmail="false" maxInvalidPasswordAttempts="5" minRequiredPasswordLength="6" minRequiredNonalphanumericCharacters="0" passwordAttemptWindow="10" applicationName="DeviceDatabase" /> </providers> </membership> When creating the MembershipUser object from my custom User class: public static MembershipUser ToMembershipUser(User user) { MembershipUser member = new MembershipUser ("MembersProvider" , user.Name , user.Id , user.EmailAddress , user.PasswordQuestion , user.Comment , user.IsApproved , user.IsLockedOut , user.DateCreated , user.LastLoginDate ?? DateTime.MinValue , user.LastActivityDate ?? DateTime.MinValue , user.LastPasswordChangedDate ?? DateTime.MinValue , user.LastLockoutDate ?? DateTime.MinValue ); return member; } (I realize I could probably just inherit my User class from MembershipUser, but it's already part of an existing class hierarchy. I honestly think this is the first time I've encountered a legitimate need for for multiple inheritance!) My feeling is that the new MembershipUser(...) providerName parameter is supposed to match what's set in web.config, but, since they match already, I'm at a loss as to how to proceed. Is there a convenient way to get the name of the active membership provider in code? I'm starting to think that using the built-in membership system is overkill and more trouble than it's worth. Edit Not sure if it's relevant, but the custom membership provider class is in a class library, not the main WAP project. Update Here's the contents of the System.Web.Security.Membership.Provider object as show in the VS2010 command window: >eval System.Web.Security.Membership.Provider {Members.Providers.MembersProvider} [Members.Providers.MembersProvider]: {Members.Providers.MembersProvider} base {System.Configuration.Provider.ProviderBase}: {Members.Providers.MembersProvider} ApplicationName: null EnablePasswordReset: true EnablePasswordRetrieval: false MaxInvalidPasswordAttempts: 5 MinRequiredNonAlphanumericCharacters: 0 MinRequiredPasswordLength: 6 PasswordAttemptWindow: 10 PasswordFormat: Function evaluation was aborted. PasswordStrengthRegularExpression: Cannot evaluate expression because debugging information has been optimized away . RequiresQuestionAndAnswer: Cannot evaluate expression because debugging information has been optimized away . RequiresUniqueEmail: Cannot evaluate expression because debugging information has been optimized away .

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  • Rush Hour - Solving the game

    - by Rubys
    Rush Hour if you're not familiar with it, the game consists of a collection of cars of varying sizes, set either horizontally or vertically, on a NxM grid that has a single exit. Each car can move forward/backward in the directions it's set in, as long as another car is not blocking it. You can never change the direction of a car. There is one special car, usually it's the red one. It's set in the same row that the exit is in, and the objective of the game is to find a series of moves (a move - moving a car N steps back or forward) that will allow the red car to drive out of the maze. I've been trying to think how to solve this problem computationally, and I can really not think of any good solution. I came up with a few: Backtracking. This is pretty simple - Recursion and some more recursion until you find the answer. However, each car can be moved a few different ways, and in each game state a few cars can be moved, and the resulting game tree will be HUGE. Some sort of constraint algorithm that will take into account what needs to be moved, and work recursively somehow. This is a very rough idea, but it is an idea. Graphs? Model the game states as a graph and apply some sort of variation on a coloring algorithm, to resolve dependencies? Again, this is a very rough idea. A friend suggested genetic algorithms. This is sort of possible but not easily. I can't think of a good way to make an evaluation function, and without that we've got nothing. So the question is - How to create a program that takes a grid and the vehicle layout, and outputs a series of steps needed to get the red car out? Sub-issues: Finding some solution. Finding an optimal solution (minimal number of moves) Evaluating how good a current state is Example: How can you move the cars in this setting, so that the red car can "exit" the maze through the exit on the right?

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  • Web P2P video confrence solution

    - by dtroy
    I'm looking for the best possible solution which will allow me to incorporate live video/audio conference between 2 users(only 2 at this point) into a flash gaming platform. The video chat is not just an extra feature, it's the main one. I'm mainly looking at open source implementations or something I'll be able to implement myself, but will consider commercial products if they are exactly what I need. Here are a few things I've looked at, but so far, I didn't find any of them good enough: Flash player 10's P2P capabilities sound promising, but I am aware of the fact that Adobe has not release any information on the RTMFP protocol and that there is no commercial server which supports it at this point. Stream all the video/audio live through a flash server (not p2p), but from my personal experience you don't get a smooth conversation. I think TokBox uses this method Java applets are a possible solution too (to perform p2p), but I don't think it will be a nice and elegant solution to combine them in the game at this point (and requires the user to authorize them). BTW, I couldn't find any useful implementations. So, If you know of any, i'll look into them. Google Gmail Video Chat uses a custom (and proprietary) browser plug-in which does the p2p and streams the video/audio into the flash player. This is a possible solution, but I rather not implement the entire p2p protocol stack + browser plug-in at this stage and concentrate on other aspect of the game itself. I think they are using XMPP based protocol similar to Jingle and they've release a Jingle librarby but without the video confrencing implementation. EDIT: In response to Branden: I am aware of Adobe Stratus. Stratus is a beta, hosted rendezvous service that aids establishing communications between Flash Player endpoints (RTMFP server). This current release of the Stratus is prerelease and is designed for evaluation purposes only. The service is not final. There is no guarantee that the service will continue to exist in the future or any information about the future cost. That's why I don't think it can be used as a commercial solution. At least not yet. I'd appreciate your suggestions and advice. thanks!

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  • What is NSString in struct?

    - by 4thSpace
    I've defined a struct and want to assign one of its values to a NSMutableDictionary. When I try, I get a EXC_BAD_ACCESS. Here is the code: //in .h file typedef struct { NSString *valueOne; NSString *valueTwo; } myStruct; myStruct aStruct; //in .m file - (void)viewDidLoad { [super viewDidLoad]; aStruct.valueOne = @"firstValue"; } //at some later time [myDictionary setValue:aStruct.valueOne forKey:@"key1"]; //dies here with EXC_BAD_ACCESS This is the output in debugger console: (gdb) p aStruct.valueOne $1 = (NSString *) 0xf41850 Is there a way to tell what the value of aStruct.valueOne is? Since it is an NSString, why does the dictionary have such a problem with it? ------------- EDIT ------------- This edit is based on some comments below. The problem appears to be in the struct memory allocation. I have no issues assigning the struct value to the dictionary in viewDidLoad, as mentioned in one of the comments. The problem is that later on, I run into an issue with the struct. Just before the error, I do: po aStruct.oneValue Program received signal EXC_BAD_ACCESS, Could not access memory. Reason: KERN_PROTECTION_FAILURE at address: 0x00000000 0x9895cedb in objc_msgSend () The program being debugged was signaled while in a function called from GDB. GDB has restored the context to what it was before the call. To change this behavior use "set unwindonsignal off" Evaluation of the expression containing the function (_NSPrintForDebugger) will be abandoned. This occurs just before the EXC_BAD_ACCESS: NSDateFormatter *formatter = [[NSDateFormatter alloc] init]; [formatter setDateFormat:@"MM-dd-yy_HH-mm-ss-A"]; NSString *date = [formatter stringFromDate:[NSDate date]]; [formatter release]; aStruct.valueOne = date; So the memory issue is most likely in my releasing of formatter. The date var has no retain. Should I instead be doing NSString *date = [[formatter stringFromDate:[NSDate date]] retain]; Which does work but then I'm left with a memory leak.

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  • Error using `loess.smooth` but not `loess` or `lowess`

    - by Sandy
    I need to smooth some simulated data, but occasionally run into problems when the simulated ordinates to be smoothed are mostly the same value. Here is a small reproducible example of the simplest case. > x <- 0:50 > y <- rep(0,51) > loess.smooth(x,y) Error in simpleLoess(y, x, w, span, degree, FALSE, FALSE, normalize = FALSE, : NA/NaN/Inf in foreign function call (arg 1) loess(y~x), lowess(x,y), and their analogue in MATLAB produce the expected results without error on this example. I am using loess.smooth here because I need the estimates evaluated at a set number of points. According to the documentation, I believe loess.smooth and loess are using the same estimation functions, but the former is an "auxiliary function" to handle the evaluation points. The error seems to come from a C function: > traceback() 3: .C(R_loess_raw, as.double(pseudovalues), as.double(x), as.double(weights), as.double(weights), as.integer(D), as.integer(N), as.double(span), as.integer(degree), as.integer(nonparametric), as.integer(order.drop.sqr), as.integer(sum.drop.sqr), as.double(span * cell), as.character(surf.stat), temp = double(N), parameter = integer(7), a = integer(max.kd), xi = double(max.kd), vert = double(2 * D), vval = double((D + 1) * max.kd), diagonal = double(N), trL = double(1), delta1 = double(1), delta2 = double(1), as.integer(0L)) 2: simpleLoess(y, x, w, span, degree, FALSE, FALSE, normalize = FALSE, "none", "interpolate", control$cell, iterations, control$trace.hat) 1: loess.smooth(x, y) loess also calls simpleLoess, but with what appears to be different arguments. Of course, if you vary enough of the y values to be nonzero, loess.smooth runs without error, but I need the program to run in even the most extreme case. Hopefully, someone can help me with one and/or all of the following: Understand why only loess.smooth, and not the other functions, produces this error and find a solution for this problem. Find a work-around using loess but still evaluating the estimate at a specified number of points that can differ from the vector x. For example, I might want to use only x <- seq(0,50,10) in the smoothing, but evaluate the estimate at x <- 0:50. As far as I know, using predict with a new data frame will not properly handle this situation, but please let me know if I am missing something there. Handle the error in a way that doesn't stop the program from moving onto the next simulated data set. Thanks in advance for any help on this problem.

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  • how to read values from the remote OPC Server

    - by Shailesh Jaiswal
    I have created one asp.net web service. In this web service I am using the web method as follows. The web service is related to the OPC ( OLE for process control) public string ReadServerItems(string ServerName) { string txt = ""; ArrayList obj = new ArrayList(); XmlServer Srv = new XmlServer("XDAGW.CS.WCF.Eval.1"); RequestOptions opt = new RequestOptions(); ReadRequestItemList iList = new ReadRequestItemList(); iList.Items = new ReadRequestItem[3]; iList.Items[0] = new ReadRequestItem(); iList.Items[0].ItemName = "ServerInfo.ConnectedClients"; iList.Items[1] = new ReadRequestItem(); iList.Items[1].ItemName = "ServerInfo.TotalGroups"; iList.Items[2] = new ReadRequestItem(); iList.Items[2].ItemName = "EventSources.Area1.Tracking"; ReplyItemList rslt; OPCError[] err; ReplyBase reply = Srv.Read(opt, iList, out rslt, out err); if ((rslt == null)) txt += err[0].Text; else { foreach (xmldanet.xmlda.ItemValue iv in rslt.Items) { txt += iv.ItemName; if (iv.ResultID == null) // success { txt += " = " + iv.Value.ToString() + "\r\n"; obj.Add(txt); } else txt += " : Error: " + iv.ResultID.Name + "\r\n"; } } return txt; } I am using the namespaces as follows using xmldanet; using xmldanet.xmlda; I have installed XMLDA.NET client component evaluation. In this there is an in built Test client which successfully reads the values of these data items from the remote OPC server. I also provides the template through which we can build the OPC based applications. In the above code I am trying to read the values of the data items but i am not able to read the values. I have applied the breakpoint. In that I can see that the condition if (iv.ResultID == null) becomes false & also there is null values in the variable rslt. Please tell me where I am doing mistake ? how should I correct my mistake ? can provide me the correct code ?

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  • Custom Tag implementation issue

    - by Appps
    I have a custom tag as follows. repeat and heading tag have doAfterBody method implemented. <csajsp:repeat reps="5"> <LI> <csajsp:heading bgColor="BLACK"> White on Black Heading </csajsp:heading> </LI> </csajsp:repeat> /* Repeat tag Class*/ public void setReps(String repeats) { System.out.println("TESTING"+repeats); //sets the reps variable. } public int doAfterBody() { System.out.println("Inside repeate tag"+reps); if (reps-- >= 1) { BodyContent body = getBodyContent(); try { JspWriter out = body.getEnclosingWriter(); System.out.println("BODY"+body.getString()); out.println(body.getString()); body.clearBody(); // Clear for next evaluation } catch(IOException ioe) { System.out.println("Error in RepeatTag: " + ioe); } return(EVAL_BODY_TAG); } else { return(SKIP_BODY); } } /* Class of Heading tag */ public int doAfterBody() { System.out.println("inside heading tag"); BodyContent body = getBodyContent(); System.out.println(body.getString()); try { JspWriter out = body.getEnclosingWriter(); out.print("NEW TEXT"); } catch(IOException ioe) { System.out.println("Error in FilterTag: " + ioe); } // SKIP_BODY means I'm done. If I wanted to evaluate // and handle the body again, I'd return EVAL_BODY_TAG. return(SKIP_BODY); } public int doEndTag() { try { JspWriter out = pageContext.getOut(); out.print("NEW TEXT 2"); } catch(IOException ioe) { System.out.println("Error in HeadingTag: " + ioe); } return(EVAL_PAGE); // Continue with rest of JSP page } The order in which SOP are printed is 1) Setter method of csajsp:repeat is called. 2) White on Black Heading is printed. ie doAfterBody of csajsp:heading tag is called. I don't know why it is not calling doAfterBody of csajsp:repeat tag. Please help me to understand this. Thanks in advance.

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  • Is this implementation truely tail-recursive?

    - by CFP
    Hello everyone! I've come up with the following code to compute in a tail-recursive way the result of an expression such as 3 4 * 1 + cos 8 * (aka 8*cos(1+(3*4))) The code is in OCaml. I'm using a list refto emulate a stack. type token = Num of float | Fun of (float->float) | Op of (float->float->float);; let pop l = let top = (List.hd !l) in l := List.tl (!l); top;; let push x l = l := (x::!l);; let empty l = (l = []);; let pile = ref [];; let eval data = let stack = ref data in let rec _eval cont = match (pop stack) with | Num(n) -> cont n; | Fun(f) -> _eval (fun x -> cont (f x)); | Op(op) -> _eval (fun x -> cont (op x (_eval (fun y->y)))); in _eval (fun x->x) ;; eval [Fun(fun x -> x**2.); Op(fun x y -> x+.y); Num(1.); Num(3.)];; I've used continuations to ensure tail-recursion, but since my stack implements some sort of a tree, and therefore provides quite a bad interface to what should be handled as a disjoint union type, the call to my function to evaluate the left branch with an identity continuation somehow irks a little. Yet it's working perfectly, but I have the feeling than in calling the _eval (fun y->y) bit, there must be something wrong happening, since it doesn't seem that this call can replace the previous one in the stack structure... Am I misunderstanding something here? I mean, I understand that with only the first call to _eval there wouldn't be any problem optimizing the calls, but here it seems to me that evaluation the _eval (fun y->y) will require to be stacked up, and therefore will fill the stack, possibly leading to an overflow... Thanks!

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  • Is there a way to keep track of the ordering of items in a dictionary?

    - by Corpsekicker
    I have a Dictionary<Guid, ElementViewModel>. (ElementViewModel is our own complex type.) I add items to the dictionary with a stock standard items.Add(Guid.NewGuid, new ElementViewModel() { /*setters go here*/ });, At a later stage I remove some or all of these items. A simplistic view of my ElementViewModel is this: class ElementViewModel { Guid Id { get; set; } string Name { get; set; } int SequenceNo { get; set; } } It may be significant to mention that the SequenceNos are compacted within the collection after adding, in case other operations like moving and copying took place. {1, 5, 6} - {1, 2, 3} A simplistic view of my remove operation is: public void RemoveElementViewModel(IEnumerable<ElementViewModel> elementsToDelete) { foreach (var elementViewModel in elementsToDelete) items.Remove(elementViewModel.Id); CompactSequenceNumbers(); } I will illustrate the problem with an example: I add 3 items to the dictionary: var newGuid = Guid.NewGuid(); items.Add(newGuid, new MineLayoutElementViewModel { Id = newGuid, SequenceNo = 1, Name = "Element 1" }); newGuid = Guid.NewGuid(); items.Add(newGuid, new MineLayoutElementViewModel { Id = newGuid, SequenceNo = 2, Name = "Element 2" }); newGuid = Guid.NewGuid(); items.Add(newGuid, new MineLayoutElementViewModel { Id = newGuid, SequenceNo = 3, Name = "Element 3" }); I remove 2 items RemoveElementViewModel(new List<ElementViewModel> { item2, item3 }); //imagine I had them cached somewhere. Now I want to add 2 other items: newGuid = Guid.NewGuid(); items.Add(newGuid, new MineLayoutElementViewModel { Id = newGuid, SequenceNo = 2, Name = "Element 2, Part 2" }); newGuid = Guid.NewGuid(); items.Add(newGuid, new MineLayoutElementViewModel { Id = newGuid, SequenceNo = 3, Name = "Element 3, Part 2" }); On evaluation of the dictionary at this point, I expected the order of items to be "Element 1", "Element 2, Part 2", "Element 3, Part 2" but it is actually in the following order: "Element 1", "Element 3, Part 2", "Element 2, Part 2" I rely on the order of these items to be a certain way. Why is it not as expected and what can I do about it?

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  • Is typeid of type name always evaluated at compile time in c++ ?

    - by cyril42e
    I wanted to check that typeid is evaluated at compile time when used with a type name (ie typeid(int), typeid(std::string)...). To do so, I repeated in a loop the comparison of two typeid calls, and compiled it with optimizations enabled, in order to see if the compiler simplified the loop (by looking at the execution time which is 1us when it simplifies instead of 160ms when it does not). And I get strange results, because sometimes the compiler simplifies the code, and sometimes it does not. I use g++ (I tried different 4.x versions), and here is the program: #include <iostream> #include <typeinfo> #include <time.h> class DisplayData {}; class RobotDisplay: public DisplayData {}; class SensorDisplay: public DisplayData {}; class RobotQt {}; class SensorQt {}; timespec tp1, tp2; const int n = 1000000000; int main() { int avg = 0; clock_gettime(CLOCK_REALTIME, &tp1); for(int i = 0; i < n; ++i) { // if (typeid(RobotQt) == typeid(RobotDisplay)) // (1) compile time // if (typeid(SensorQt) == typeid(SensorDisplay)) // (2) compile time if (typeid(RobotQt) == typeid(RobotDisplay) || typeid(SensorQt) == typeid(SensorDisplay)) // (3) not compile time ???!!! avg++; else avg--; } clock_gettime(CLOCK_REALTIME, &tp2); std::cout << "time (" << avg << "): " << (tp2.tv_sec-tp1.tv_sec)*1000000000+(tp2.tv_nsec-tp1.tv_nsec) << " ns" << std::endl; } The conditions in which this problem appear are not clear, but: - if there is no inheritance involved, no problem (always compile time) - if I do only one comparison, no problem - the problem only appears only with a disjunction of comparisons if all the terms are false So is there something I didn't get with how typeid works (is it always supposed to be evaluated at compilation time when used with type names?) or may this be a gcc bug in evaluation or optimization? About the context, I tracked down the problem to this very simplified example, but my goal is to use typeid with template types (as partial function template specialization is not possible). Thanks for your help!

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  • Unable to set nginx to serve my staging website

    - by user100778
    I'm having some troubles setting up nginx to serve my staging website. What I did is change the server_name but for some reasons it just doesn't work. The url scheme is "domain.foo" is production, "staging.domain.foo" is staging, "foobar.domain.foo" is a web service, "foobar.staging.domain.foo" is the staging version of the same webserver, ".domain.foo" is routed to serve some s3 static HTML, ".staging.domain.foo" is routed to serve some s3 static HTML in another bucket. All production urls work and are correctly configured, all staging urls doesn't work. Here is my conf file. You will see some duplication, I will gladly accept any correction/optimization, I'm a coder and configuring servers is definitely not my thing (but I'm eager to learn and improve...). server { listen 80; ## listen for ipv4 server_name "domain.foo" "www.domain.foo" default_server; access_log /var/log/nginx/access.log; client_max_body_size 5M; location / { proxy_set_header X-Real-IP $remote_addr; proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for; proxy_set_header Host $http_host; proxy_redirect off; location ~* \.(jpg|jpeg|gif|png|ico|css|bmp|js|html)$ { access_log off; expires max; root /home/foo/Foo/current/public; break; } if ($host ~ 'www.domain.foo') { rewrite ^/(.*)$ http://domain/foo/$1 permanent; } proxy_pass http://production; break; } } server { listen 80; server_name "staging.domain.foo"; access_log /var/log/nginx/access.staging.log; error_log /var/log/nginx/error.staging.log; client_max_body_size 5M; location / { proxy_set_header X-Real-IP $remote_addr; proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for; proxy_set_header Host $http_host; proxy_redirect off; proxy_pass http://staging; break; } } server { listen 80; ## listen for ipv4 server_name "foobar.domain.foo"; access_log /var/log/nginx/access.log; location / { proxy_set_header X-Real-IP $remote_addr; proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for; proxy_set_header Host $http_host; proxy_redirect off; if ($host = 'foobar.domain.foo') { proxy_pass http://foobar; break; } } } server { listen 80; ## listen for ipv4 server_name foobar.staging.domain.foo; location / { proxy_set_header X-Real-IP $remote_addr; proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for; proxy_set_header Host $http_host; proxy_redirect off; proxy_pass http://foobar_staging; break; } } server { listen 80; server_name "~^(.+)\.domain\.foo$"; location / { proxy_intercept_errors on; error_page 404 = http://domain.foo/404; set $subdomain $1; rewrite /$ "/$subdomain/index.html" break; rewrite ^ /$subdomain$request_uri? break; proxy_pass http://bucket.domain.foo.s3.amazonaws.com; } } server { listen 80; server_name "~^(.+)\.staging\.domain\.foo$"; location / { proxy_intercept_errors on; set $subdomain $1; rewrite /$ "/$subdomain/index.html" break; rewrite ^ /$subdomain$request_uri? break; proxy_pass http://bucket.staging.domain.foo.s3.amazonaws.com; } } upstream production { server 111.255.111.110:8000; server 111.255.111.110:8001; server 111.255.111.110:8002; server 111.255.111.110:8003; } upstream staging { server 222.255.222.222:8000; server 222.255.222.222:8001; } upstream foobar { server 111.255.222.165:9000; server 111.255.222.165:9001; server 111.255.222.165:9002; } upstream foobar_staging { server 222.255.222.222:9000; } What happens now when I point my browser to staging.domain.foo is that it hangs. Can't find anything in the logs, but for example the access.staging.log and errors.staging.log are created. Anybody has an idea? :)

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  • rm on a directory with millions of files

    - by BMDan
    Background: physical server, about two years old, 7200-RPM SATA drives connected to a 3Ware RAID card, ext3 FS mounted noatime and data=ordered, not under crazy load, kernel 2.6.18-92.1.22.el5, uptime 545 days. Directory doesn't contain any subdirectories, just millions of small (~100 byte) files, with some larger (a few KB) ones. We have a server that has gone a bit cuckoo over the course of the last few months, but we only noticed it the other day when it started being unable to write to a directory due to it containing too many files. Specifically, it started throwing this error in /var/log/messages: ext3_dx_add_entry: Directory index full! The disk in question has plenty of inodes remaining: Filesystem Inodes IUsed IFree IUse% Mounted on /dev/sda3 60719104 3465660 57253444 6% / So I'm guessing that means we hit the limit of how many entries can be in the directory file itself. No idea how many files that would be, but it can't be more, as you can see, than three million or so. Not that that's good, mind you! But that's part one of my question: exactly what is that upper limit? Is it tunable? Before I get yelled at--I want to tune it down; this enormous directory caused all sorts of issues. Anyway, we tracked down the issue in the code that was generating all of those files, and we've corrected it. Now I'm stuck with deleting the directory. A few options here: rm -rf (dir)I tried this first. I gave up and killed it after it had run for a day and a half without any discernible impact. unlink(2) on the directory: Definitely worth consideration, but the question is whether it'd be faster to delete the files inside the directory via fsck than to delete via unlink(2). That is, one way or another, I've got to mark those inodes as unused. This assumes, of course, that I can tell fsck not to drop entries to the files in /lost+found; otherwise, I've just moved my problem. In addition to all the other concerns, after reading about this a bit more, it turns out I'd probably have to call some internal FS functions, as none of the unlink(2) variants I can find would allow me to just blithely delete a directory with entries in it. Pooh. while [ true ]; do ls -Uf | head -n 10000 | xargs rm -f 2/dev/null; done ) This is actually the shortened version; the real one I'm running, which just adds some progress-reporting and a clean stop when we run out of files to delete, is: export i=0; time ( while [ true ]; do ls -Uf | head -n 3 | grep -qF '.png' || break; ls -Uf | head -n 10000 | xargs rm -f 2/dev/null; export i=$(($i+10000)); echo "$i..."; done ) This seems to be working rather well. As I write this, it's deleted 260,000 files in the past thirty minutes or so. Now, for the questions: As mentioned above, is the per-directory entry limit tunable? Why did it take "real 7m9.561s / user 0m0.001s / sys 0m0.001s" to delete a single file which was the first one in the list returned by "ls -U", and it took perhaps ten minutes to delete the first 10,000 entries with the command in #3, but now it's hauling along quite happily? For that matter, it deleted 260,000 in about thirty minutes, but it's now taken another fifteen minutes to delete 60,000 more. Why the huge swings in speed? Is there a better way to do this sort of thing? Not store millions of files in a directory; I know that's silly, and it wouldn't have happened on my watch. Googling the problem and looking through SF and SO offers a lot of variations on "find" that obviously have the wrong idea; it's not going to be faster than my approach for several self-evident reasons. But does the delete-via-fsck idea have any legs? Or something else entirely? I'm eager to hear out-of-the-box (or inside-the-not-well-known-box) thinking. Thanks for reading the small novel; feel free to ask questions and I'll be sure to respond. I'll also update the question with the final number of files and how long the delete script ran once I have that. Final script output!: 2970000... 2980000... 2990000... 3000000... 3010000... real 253m59.331s user 0m6.061s sys 5m4.019s So, three million files deleted in a bit over four hours.

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  • Windows Server 2012 Migration (DNS/AD DS Standard Eval to Essentials OEM) P2V -> Do I need a Secondary Domain Controller during migration?

    - by Aubrey Robertson
    This is my first post on this exchange (although not my first on stack exchange), so please have patience. I am a 3rd year student intern, and I have been tasked with virtualizing the server systems at the company I work for. I have come a long way, and I am almost ready to install the VM Server in migration mode. Here is some information: Source Server: Windows Server 2012 Standard Evaluation DNS Server (local only) Advanced Directory Domain Services File and Storage stuff A few other server roles Destination Server: Windows Server 2012 Essentials OEM (Hyper-V client) Running under a temporary Hyper-V host (will migrate the Hyper-V host back to the old machine after the original server is virtualized as a client). Sitting currently at the "Select Installation Mode" screen. I have been following the guides on Microsoft tech net, and today I spent most of the day getting rid of issues in the Best Practices Analyser on the source machine. I have 3 remaining issues (which are all related): ERROR: DNS: DNS servers on Ethernet (adapter name) should include the loopback address, but not as the first entry (flavour text indicates that, during migration, the DNS server may not be found) WARNING: All domains should have at least two domain controllers for redundancy. WARNING: DNS: Ethernet should be configured to use both a preferred and an alternate DNS Server. All of these issues can be resolved by deploying a secondary domain controller, but I have never done that before (see my concerns below). The main issue here that I am concerned with for installing in migration mode is the FIRST one (the error). If I try and set-up the new server deployment, and the adapter domain controller is listed as localhost, then this may cause the installation to fail. (at least, this is what the Microsoft documentation suggests). But I do not have another IP address to enter here as I have no other local domain controllers. So I did the first obvious thing that came to my mind, and tried to use Google DNS servers as my alternates. That did not work because they couldn't recognize other computers in the "forest". Now I'm no expert when it comes to DNS, so please forgive my ignorance. This DNS server is concerned only with Active Directory stuffs for the local network. If I go ahead with migration, and it fails, then I will just have to go ahead and install a secondary DNS server I suppose. The problem I have here is that I am limited by the amount of Windows Server keys I have available (I have 2); however, I do have access to a Linux box running Debian Wheezy that I set-up two weeks ago as a Mantis server. I could install Windows Server 2012 as a secondary DNS (I think) in a VM and use that, but then it seems like I will be wasting time, and probably the Windows key too, and if there's another way to do it with Linux that would be much better. Even better still, do I even need a secondary DNS server for migration at all? The hints said that during migration the original machine "might" not be found. Thank you for your time and consideration.

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  • Deleting unreferenced child records with nhibernate

    - by Chev
    Hi There I am working on a mvc app using nhibernate as the orm (ncommon framework) I have parent/child entities: Product, Vendor & ProductVendors and a one to many relationship between them with Product having a ProductVendors collection Product.ProductVendors. I currently am retrieving a Product object and eager loading the children and sending these down the wire to my asp.net mvc client. A user will then modify the list of Vendors and post the updated Product back. I am using a custom model binder to generate the modified Product entity. I am able to update the Product fine and insert new ProductVendors. My problem is that dereferenced ProductVendors are not cascade deleted when specifying Product.ProductVendors.Clear() and calling _productRepository.Save(product). The problem seems to be with attaching the detached instance. Here are my mapping files: Product <?xml version="1.0" encoding="utf-8" ?> <id name="Id"> <generator class="guid.comb" /> </id> <version name="LastModified" unsaved-value="0" column="LastModified" /> <property name="Name" type="String" length="250" /> ProductVendors <?xml version="1.0" encoding="utf-8" ?> <id name="Id"> <generator class="guid.comb" /> </id> <version name="LastModified" unsaved-value="0" column="LastModified" /> <property name="Price" /> <many-to-one name="Product" class="Product" column="ProductId" lazy="false" not-null="true" /> <many-to-one name="Vendor" class="Vendor" column="VendorId" lazy="false" not-null="true" /> Custom Model Binder: using System; using Test.Web.Mvc; using Test.Domain; namespace Spoked.MVC { public class ProductUpdateModelBinder : DefaultModelBinder { private readonly ProductSystem ProductSystem; public ProductUpdateModelBinder(ProductSystem productSystem) { ProductSystem = productSystem; } protected override void OnModelUpdated(ControllerContext controllerContext, ModelBindingContext bindingContext) { var product = bindingContext.Model as Product; if (product != null) { product.Category = ProductSystem.GetCategory(new Guid(bindingContext.ValueProvider["Category"].AttemptedValue)); product.Brand = ProductSystem.GetBrand(new Guid(bindingContext.ValueProvider["Brand"].AttemptedValue)); product.ProductVendors.Clear(); if (bindingContext.ValueProvider["ProductVendors"] != null) { string[] productVendorIds = bindingContext.ValueProvider["ProductVendors"].AttemptedValue.Split(','); foreach (string id in productVendorIds) { product.AddProductVendor(ProductSystem.GetVendor(new Guid(id)), 90m); } } } } } } Controller: [AcceptVerbs(HttpVerbs.Post)] public ActionResult Update(Product product) { using (var scope = new UnitOfWorkScope()) { //product.ProductVendors.Clear(); _productRepository.Save(product); scope.Commit(); } using (new UnitOfWorkScope()) { IList<Vendor> availableVendors = _productSystem.GetAvailableVendors(product); productDetailEditViewModel = new ProductDetailEditViewModel(product, _categoryRepository.Select(x => x).ToList(), _brandRepository.Select(x => x).ToList(), availableVendors); } return RedirectToAction("Edit", "Products", new {id = product.Id.ToString()}); } The following test does pass though: [Test] [NUnit.Framework.Category("ProductTests")] public void Can_Delete_Product_Vendors_By_Dereferencing() { Product product; using(UnitOfWorkScope scope = new UnitOfWorkScope()) { Console.Out.WriteLine("Selecting..."); product = _productRepository.First(); Console.Out.WriteLine("Adding Product Vendor..."); product.AddProductVendor(_vendorRepository.First(), 0m); scope.Commit(); } Console.Out.WriteLine("About to delete Product Vendors..."); using (UnitOfWorkScope scope = new UnitOfWorkScope()) { Console.Out.WriteLine("Clearing Product Vendor..."); _productRepository.Save(product); // seems to be needed to attach entity to the persistance manager product.ProductVendors.Clear(); scope.Commit(); } } Going nuts here as I almost have a very nice solution between mvc, custom model binders and nhibernate. Just not seeing my deletes cascaded. Any help greatly appreciated. Chev

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  • Foreign key not stored in child entity (one-to-many)

    - by Kamil Los
    Hi, I'm quite new to hibernate and have stumbled on this problem, which I can't find solution for. When persisting parent object (with one-to-many relationship with child), the foreign-key to this parent is not stored in child's table. My classes: Parent.java @javax.persistence.Table(name = "PARENT") @Entity public class PARENT { private Integer id; @javax.persistence.Column(name = "ID") @Id @GeneratedValue(strategy=GenerationType.AUTO) public Integer getId() { return id; } public void setId(Integer id) { this.id = id; } private Collection<Child> children; @OneToMany(mappedBy = "parent", fetch = FetchType.EAGER, cascade = {CascadeType.ALL}) @Cascade({org.hibernate.annotations.CascadeType.ALL}) public Collection<Child> getChildren() { return children; } public void setChildren(Collection<Child> children) { this.children = children; } } Child.java @javax.persistence.Table(name = "CHILD") @Entity @IdClass(Child.ChildId.class) public class Child { private String childId1; @Id public String getChildId1() { return childId1; } public void setChildId1(String childId1) { this.childId1 = childId1; } private String childId2; @Id public String getChildId2() { return childId2; } public void setChildId2(String childId2) { this.childId2 = childId2; } private Parent parent; @ManyToOne @javax.persistence.JoinColumn(name = "PARENT_ID", referencedColumnName = "ID") public Parent getParent() { return parent; } public void setParent(Operation parent) { this.parent = parent; } public static class ChildId implements Serializable { private String childId1; @javax.persistence.Column(name = "CHILD_ID1") public String getChildId1() { return childId1; } public void setChildId1(String childId1) { this.childId1 = childId1; } private String childId2; @javax.persistence.Column(name = "CHIILD_ID2") public String getChildId2() { return childId2; } public void setChildId2(String childId2) { this.childId2 = childId2; } public ChildId() { } @Override public boolean equals(Object o) { if (this == o) return true; if (o == null || getClass() != o.getClass()) return false; ChildId that = (ChildId) o; if (childId1 != null ? !childId1.equals(that.childId1) : that.childId1 != null) return false; if (childId2 != null ? !childId2.equals(that.childId2) : that.childId2 != null) return false; return true; } @Override public int hashCode() { int result = childId1 != null ? childId1.hashCode() : 0; result = 31 * result + (childId2 != null ? childId2.hashCode() : 0); return result; } } } Test.java public class Test() { private ParentDao parentDao; public void setParentDao(ParentDao parentDao) { this.parentDao = parentDao; } private ChildDao childDao; public void setChildDao(ChildDao childDao) { this.childDao = parentDao; } test1() { Parent parent = new Parent(); Child child = new Child(); child.setChildId1("a"); child.setChildId2("b"); ArrayList<Child> children = new ArrayList<Child>(); children.add(child); parent.setChildren(children); parent.setValue("value"); parentDao.save(parent); //calls hibernate's currentSession.saveOrUpdate(entity) } test2() { Parent parent = new Parent(); parent.setValue("value"); parentDao.save(parent); //calls hibernate's currentSession.saveOrUpdate(entity) Child child = new Child(); child.setChildId1("a"); child.setChildId2("b"); child.setParent(parent); childDao.save(); //calls hibernate's currentSession.saveOrUpdate(entity) } } When calling test1(), both entities get written to database, but field PARENT_ID in CHILD table stays empty. The only workaround I have so far is test2() - persisting parent first, and then the child. My goal is to persist parent and its children in one call to save() on Parent. Any ideas?

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  • The dynamic Type in C# Simplifies COM Member Access from Visual FoxPro

    - by Rick Strahl
    I’ve written quite a bit about Visual FoxPro interoperating with .NET in the past both for ASP.NET interacting with Visual FoxPro COM objects as well as Visual FoxPro calling into .NET code via COM Interop. COM Interop with Visual FoxPro has a number of problems but one of them at least got a lot easier with the introduction of dynamic type support in .NET. One of the biggest problems with COM interop has been that it’s been really difficult to pass dynamic objects from FoxPro to .NET and get them properly typed. The only way that any strong typing can occur in .NET for FoxPro components is via COM type library exports of Visual FoxPro components. Due to limitations in Visual FoxPro’s type library support as well as the dynamic nature of the Visual FoxPro language where few things are or can be described in the form of a COM type library, a lot of useful interaction between FoxPro and .NET required the use of messy Reflection code in .NET. Reflection is .NET’s base interface to runtime type discovery and dynamic execution of code without requiring strong typing. In FoxPro terms it’s similar to EVALUATE() functionality albeit with a much more complex API and corresponiding syntax. The Reflection APIs are fairly powerful, but they are rather awkward to use and require a lot of code. Even with the creation of wrapper utility classes for common EVAL() style Reflection functionality dynamically access COM objects passed to .NET often is pretty tedious and ugly. Let’s look at a simple example. In the following code I use some FoxPro code to dynamically create an object in code and then pass this object to .NET. An alternative to this might also be to create a new object on the fly by using SCATTER NAME on a database record. How the object is created is inconsequential, other than the fact that it’s not defined as a COM object – it’s a pure FoxPro object that is passed to .NET. Here’s the code: *** Create .NET COM InstanceloNet = CREATEOBJECT('DotNetCom.DotNetComPublisher') *** Create a Customer Object Instance (factory method) loCustomer = GetCustomer() loCustomer.Name = "Rick Strahl" loCustomer.Company = "West Wind Technologies" loCustomer.creditLimit = 9999999999.99 loCustomer.Address.StreetAddress = "32 Kaiea Place" loCustomer.Address.Phone = "808 579-8342" loCustomer.Address.Email = "[email protected]" *** Pass Fox Object and echo back values ? loNet.PassRecordObject(loObject) RETURN FUNCTION GetCustomer LOCAL loCustomer, loAddress loCustomer = CREATEOBJECT("EMPTY") ADDPROPERTY(loCustomer,"Name","") ADDPROPERTY(loCustomer,"Company","") ADDPROPERTY(loCUstomer,"CreditLimit",0.00) ADDPROPERTY(loCustomer,"Entered",DATETIME()) loAddress = CREATEOBJECT("Empty") ADDPROPERTY(loAddress,"StreetAddress","") ADDPROPERTY(loAddress,"Phone","") ADDPROPERTY(loAddress,"Email","") ADDPROPERTY(loCustomer,"Address",loAddress) RETURN loCustomer ENDFUNC Now prior to .NET 4.0 you’d have to access this object passed to .NET via Reflection and the method code to do this would looks something like this in the .NET component: public string PassRecordObject(object FoxObject) { // *** using raw Reflection string Company = (string) FoxObject.GetType().InvokeMember( "Company", BindingFlags.GetProperty,null, FoxObject,null); // using the easier ComUtils wrappers string Name = (string) ComUtils.GetProperty(FoxObject,"Name"); // Getting Address object – then getting child properties object Address = ComUtils.GetProperty(FoxObject,"Address");    string Street = (string) ComUtils.GetProperty(FoxObject,"StreetAddress"); // using ComUtils 'Ex' functions you can use . Syntax     string StreetAddress = (string) ComUtils.GetPropertyEx(FoxObject,"AddressStreetAddress"); return Name + Environment.NewLine + Company + Environment.NewLine + StreetAddress + Environment.NewLine + " FOX"; } Note that the FoxObject is passed in as type object which has no specific type. Since the object doesn’t exist in .NET as a type signature the object is passed without any specific type information as plain non-descript object. To retrieve a property the Reflection APIs like Type.InvokeMember or Type.GetProperty().GetValue() etc. need to be used. I made this code a little simpler by using the Reflection Wrappers I mentioned earlier but even with those ComUtils calls the code is pretty ugly requiring passing the objects for each call and casting each element. Using .NET 4.0 Dynamic Typing makes this Code a lot cleaner Enter .NET 4.0 and the dynamic type. Replacing the input parameter to the .NET method from type object to dynamic makes the code to access the FoxPro component inside of .NET much more natural: public string PassRecordObjectDynamic(dynamic FoxObject) { // *** using raw Reflection string Company = FoxObject.Company; // *** using the easier ComUtils class string Name = FoxObject.Name; // *** using ComUtils 'ex' functions to use . Syntax string Address = FoxObject.Address.StreetAddress; return Name + Environment.NewLine + Company + Environment.NewLine + Address + Environment.NewLine + " FOX"; } As you can see the parameter is of type dynamic which as the name implies performs Reflection lookups and evaluation on the fly so all the Reflection code in the last example goes away. The code can use regular object ‘.’ syntax to reference each of the members of the object. You can access properties and call methods this way using natural object language. Also note that all the type casts that were required in the Reflection code go away – dynamic types like var can infer the type to cast to based on the target assignment. As long as the type can be inferred by the compiler at compile time (ie. the left side of the expression is strongly typed) no explicit casts are required. Note that although you get to use plain object syntax in the code above you don’t get Intellisense in Visual Studio because the type is dynamic and thus has no hard type definition in .NET . The above example calls a .NET Component from VFP, but it also works the other way around. Another frequent scenario is an .NET code calling into a FoxPro COM object that returns a dynamic result. Assume you have a FoxPro COM object returns a FoxPro Cursor Record as an object: DEFINE CLASS FoxData AS SESSION OlePublic cAppStartPath = "" FUNCTION INIT THIS.cAppStartPath = ADDBS( JustPath(Application.ServerName) ) SET PATH TO ( THIS.cAppStartpath ) ENDFUNC FUNCTION GetRecord(lnPk) LOCAL loCustomer SELECT * FROM tt_Cust WHERE pk = lnPk ; INTO CURSOR TCustomer IF _TALLY < 1 RETURN NULL ENDIF SCATTER NAME loCustomer MEMO RETURN loCustomer ENDFUNC ENDDEFINE If you call this from a .NET application you can now retrieve this data via COM Interop and cast the result as dynamic to simplify the data access of the dynamic FoxPro type that was created on the fly: int pk = 0; int.TryParse(Request.QueryString["id"],out pk); // Create Fox COM Object with Com Callable Wrapper FoxData foxData = new FoxData(); dynamic foxRecord = foxData.GetRecord(pk); string company = foxRecord.Company; DateTime entered = foxRecord.Entered; This code looks simple and natural as it should be – heck you could write code like this in days long gone by in scripting languages like ASP classic for example. Compared to the Reflection code that previously was necessary to run similar code this is much easier to write, understand and maintain. For COM interop and Visual FoxPro operation dynamic type support in .NET 4.0 is a huge improvement and certainly makes it much easier to deal with FoxPro code that calls into .NET. Regardless of whether you’re using COM for calling Visual FoxPro objects from .NET (ASP.NET calling a COM component and getting a dynamic result returned) or whether FoxPro code is calling into a .NET COM component from a FoxPro desktop application. At one point or another FoxPro likely ends up passing complex dynamic data to .NET and for this the dynamic typing makes coding much cleaner and more readable without having to create custom Reflection wrappers. As a bonus the dynamic runtime that underlies the dynamic type is fairly efficient in terms of making Reflection calls especially if members are repeatedly accessed. © Rick Strahl, West Wind Technologies, 2005-2010Posted in COM  FoxPro  .NET  CSharp  

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