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  • How I Work: A Cloud Developer's Workstation

    - by BuckWoody
    I've written here a little about how I work during the day, including things like using a stand-up desk (still doing that, by the way). Inspired by a Twitter conversation yesterday, I thought I might explain how I set up my computing environment. First, a couple of important points. I work in Cloud Computing, specifically (but not limited to) Windows Azure. Windows Azure has features to run a Virtual Machine (IaaS), run code without having to control a Virtual Machine (PaaS) and use databases, video streaming, Hadoop and more (a kind of SaaS for tech pros). As such, my designs run the gamut of on-premises, VM's in the Cloud, and software that I write for a platform. I focus on data primarily, meaning that I design a lot of systems that use an RDBMS (like SQL Server or Windows Azure Databases) or a NoSQL approach (MongoDB on Azure or large-scale Key-Value Pairs in Table storage) and even Hadoop and R, and also Cloud Numerics in F#. All that being said, those things inform my choices below. Hardware I have a Lenovo X220 tablet/laptop which I really like a great deal - it's a light, tough, extremely fast system. When I travel, that's the system I take. It has 8GB of RAM, and an SSD drive. I sometimes use that to develop or work at a client's site, on the road, or in the living room when I'm not in my home office. My main system is a GateWay DX430017 - I've maxed it out on RAM, and I have two 1TB drives in it. It's not only my workstation for work; I leave it on all the time and it streams our videos, music and books. I have about 3400 e-books, and I've just started using Calibre to stream the library. I run Windows 8 on it so I can set up Hyper-V images, since Windows Azure allows me to move regular Hyper-V disks back and forth to the Cloud. That's where all my "servers" are, when I have to use an IaaS approach. The reason I use a desktop-style system rather than a laptop only approach is that a good part of my job is setting up architectures to solve really big, complex problems. That means I have to simulate entire networks on-premises, along with the Hybrid Cloud approach I use a lot. I need a lot of disk space and memory for that, and I use two huge monitors on my stand-up desk. I could probably use 10 monitors if I had the room for them. Also, since it's our home system as well, I leave it on all the time and it doesn't travel.   Software For the software for my systems, it's important to keep in mind that I not only write code, but I design databases, teach, present, and create Linux and other environments. Windows 8 - While the jury is out for me on the new interface, the context-sensitive search, integrated everything, and speed is just hands-down the right choice. I've evaluated a server OS, Linux, even an Apple, but I just am not as efficient on those as I am with Windows 8. Visual Studio Ultimate - I develop primarily in .NET (C# and F# mostly) and I use the Team Foundation Server in the cloud, and I'm asked to do everything from UI to Services, so I need everything. Windows Azure SDK, Windows Azure Training Kit - I need the first to set up my Azure PaaS coding, and the second has all the info I need for PaaS, IaaS and SaaS. This is primarily how I get paid. :) SQL Server Developer Edition - While I might install Oracle, MySQL and Postgres on my VM's, the "outside" environment is SQL Server for an RDBMS. I install the Developer Edition because it has the same features as Enterprise Edition, and comes with all the client tools and documentation. Microsoft Office -  Even if I didn't work here, this is what I would use. I've just grown too accustomed to doing business this way to change, so my advice is always "use what works", and this does. The parts I use are: OneNote (and a Math Add-in) - I do almost everything - and I mean everything in OneNote. I can code, do high-end math, present, design, collaborate and more. All my notebooks are on my Skydrive. I can use them from any system, anywhere. If you take the time to learn this program, you'll be hooked. Excel with PowerPivot - Don't make that face. Excel is the world's database, and every Data Scientist I know - even the ones where I teach at the University of Washington - know it, use it, and love it.  Outlook - Primary communications, CRM and contact tool. I have all of my social media hooked up to it, so when I get an e-mail from you, I see everything, see all the history we've had on e-mail, find you on a map and more. Lync - I was fine with LiveMeeting, although it has it's moments. For me, the Lync client is tres-awesome. I use this throughout my day, present on it, stay in contact with colleagues and the folks on the dev team (who wish I didn't have it) and more.  PowerPoint - Once again, don't make that face. Whenever I see someone complaining about PowerPoint, I have 100% of the time found they don't know how to use it. If you suck at presenting or creating content, don't blame PowerPoint. Works great on my machine. :) Zoomit - Magnifier - On Windows 7 (and 8 as well) there's a built-in magnifier, but I install Zoomit out of habit. It enlarges the screen. If you don't use one of these tools (or their equivalent on some other OS) then you're presenting/teaching wrong, and you should stop presenting/teaching until you get them and learn how to show people what you can see on your tiny, tiny monitor. :) Cygwin - Unix for Windows. OK, that's not true, but it's mostly that. I grew up on mainframes and Unix (IBM and HP, thank you) and I can't imagine life without  sed, awk, grep, vim, and bash. I also tend to take a lot of the "Science" and "Development" and "Database" packages in it as well. PuTTY - Speaking of Unix, when I need to connect to my Linux VM's in Windows Azure, I want to do it securely. This is the tool for that. Notepad++ - Somewhere between torturing myself in vim and luxuriating in OneNote is Notepad++. Everyone has a favorite text editor; this one is mine. Too many features to name, and it's free. Browsers - I install Chrome, Firefox and of course IE. I know it's in vogue to rant on IE, but I tend to think for myself a great deal, and I've had few (none) problems with it. The others I have for the haterz that make sites that won't run in IE. Visio - I've used a lot of design packages, but none have the extreme meta-data edit capabilities of Visio. I don't use this all the time - it can be rather heavy, but what it does it does really well. I also present this way when I'm not using PowerPoint. Yup, I just bring up Visio and diagram away as I'm chatting with clients. Depending on what we're covering, this can be the right tool for that. Tweetdeck - The AIR one, not that new disaster they came out with. I live on social media, since you, dear readers, are my cube-mates. When I get tired of you all, I close Tweetdeck. When I need help or someone needs help from me, or if I want to see a picture of a cat while I'm coding, I bring it up. It's up most all day and night. Windows Media Player - I listen to Trance or Classical when I code, and I find music managers overbearing and extra. I just use what comes in the box, and it works great for me. R - F# and Cloud Numerics now allows me to load in R libraries (yay!) and I use this for statistical work on big data loads. Microsoft Math - One of the most amazing, free, rich, amazing, awesome, amazing calculators out there. I get the 64-bit version for quick math conversions, plots and formula-checks. Python - I know, right? Who knew that the scientific community loved Python so much. But they do. I use 2.7; not as much runs with 3+. I also use IronPython in Visual Studio, or I edit in Notepad++ Camstudio recorder - Windows PSR - In much of my training, and all of my teaching at the UW, I need to show a process on a screen. Camstudio records screen and voice, and it's free. If I need to make static training, I use the Windows PSR tool that's built right in. It's ostensibly for problem duplication, but I use it to record for training.   OK - your turn. Post a link to your blog entry below, and tell me how you set your system up.  

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  • Making a Case For The Command Line

    - by Jesse Taber
    Originally posted on: http://geekswithblogs.net/GruffCode/archive/2013/06/30/making-a-case-for-the-command-line.aspxI have had an idea percolating in the back of my mind for over a year now that I’ve just recently started to implement. This idea relates to building out “internal tools” to ease the maintenance and on-going support of a software system. The system that I currently work on is (mostly) web-based, so we traditionally we have built these internal tools in the form of pages within the app that are only accessible by our developers and support personnel. These pages allow us to perform tasks within the system that, for one reason or another, we don’t want to let our end users perform (e.g. mass create/update/delete operations on data, flipping switches that turn paid modules of the system on or off, etc). When we try to build new tools like this we often struggle with the level of effort required to build them. Effort Required Creating a whole new page in an existing web application can be a fairly large undertaking. You need to create the page and ensure it will have a layout that is consistent with the other pages in the app. You need to decide what types of input controls need to go onto the page. You need to ensure that everything uses the same style as the rest of the site. You need to figure out what the text on the page should say. Then, when you figure out that you forgot about an input that should really be present you might have to go back and re-work the entire thing. Oh, and in addition to all of that, you still have to, you know, write the code that actually performs the task. Everything other than the code that performs the task at hand is just overhead. We don’t need a fancy date picker control in a nicely styled page for the vast majority of our internal tools. We don’t even really need a page, for that matter. We just need a way to issue a command to the application and have it, in turn, execute the code that we’ve written to accomplish a given task. All we really need is a simple console application! Plumbing Problems A former co-worker of mine, John Sonmez, always advocated the Unix philosophy for building internal tools: start with something that runs at the command line, and then build a UI on top of that if you need to. John’s idea has a lot of merit, and we tried building out some internal tools as simple Console applications. Unfortunately, this was often easier said that done. Doing a “File –> New Project” to build out a tool for a mature system can be pretty daunting because that new project is totally empty.  In our case, the web application code had a lot of of “plumbing” built in: it managed authentication and authorization, it handled database connection management for our multi-tenanted architecture, it managed all of the context that needs to follow a user around the application such as their timezone and regional/language settings. In addition, the configuration file for the web application  (a web.config in our case because this is an ASP .NET application) is large and would need to be reproduced into a similar configuration file for a Console application. While most of these problems are could be solved pretty easily with some refactoring of the codebase, building Console applications for internal tools still potentially suffers from one pretty big drawback: you’d have to execute them on a machine with network access to all of the needed resources. Obviously, our web servers can easily communicate the the database servers and can publish messages to our service bus, but the same is not true for all of our developer and support personnel workstations. We could have everyone run these tools remotely via RDP or SSH, but that’s a bit cumbersome and certainly a lot less convenient than having the tools built into the web application that is so easily accessible. Mix and Match So we need a way to build tools that are easily accessible via the web application but also don’t require the overhead of creating a user interface. This is where my idea comes into play: why not just build a command line interface into the web application? If it’s part of the web application we get all of the plumbing that comes along with that code, and we’re executing everything on the web servers which means we’ll have access to any external resources that we might need. Rather than having to incur the overhead of creating a brand new page for each tool that we want to build, we can create one new page that simply accepts a command in text form and executes it as a request on the web server. In this way, we can focus on writing the code to accomplish the task. If the tool ends up being heavily used, then (and only then) should we consider spending the time to build a better user experience around it. To be clear, I’m not trying to downplay the importance of building great user experiences into your system; we should all strive to provide the best UX possible to our end users. I’m only advocating this sort of bare-bones interface for internal consumption by the technical staff that builds and supports the software. This command line interface should be the “back end” to a highly polished and eye-pleasing public face. Implementation As I mentioned at the beginning of this post, this is an idea that I’ve had for awhile but have only recently started building out. I’ve outlined some general guidelines and design goals for this effort as follows: Text in, text out: In the interest of keeping things as simple as possible, I want this interface to be purely text-based. Users will submit commands as plain text, and the application will provide responses in plain text. Obviously this text will be “wrapped” within the context of HTTP requests and responses, but I don’t want to have to think about HTML or CSS when taking input from the user or displaying responses back to the user. Task-oriented code only: After building the initial “harness” for this interface, the only code that should need to be written to create a new internal tool should be code that is expressly needed to accomplish the task that the tool is intended to support. If we want to encourage and enable ourselves to build good tooling, we need to lower the barriers to entry as much as possible. Built-in documentation: One of the great things about most command line utilities is the ‘help’ switch that provides usage guidelines and details about the arguments that the utility accepts. Our web-based command line utility should allow us to build the documentation for these tools directly into the code of the tools themselves. I finally started trying to implement this idea when I heard about a fantastic open-source library called CLAP (Command Line Auto Parser) that lets me meet the guidelines outlined above. CLAP lets you define classes with public methods that can be easily invoked from the command line. Here’s a quick example of the code that would be needed to create a new tool to do something within your system: 1: public class CustomerTools 2: { 3: [Verb] 4: public void UpdateName(int customerId, string firstName, string lastName) 5: { 6: //invoke internal services/domain objects/hwatever to perform update 7: } 8: } This is just a regular class with a single public method (though you could have as many methods as you want). The method is decorated with the ‘Verb’ attribute that tells the CLAP library that it is a method that can be invoked from the command line. Here is how you would invoke that code: Parser.Run(args, new CustomerTools()); Note that ‘args’ is just a string[] that would normally be passed passed in from the static Main method of a Console application. Also, CLAP allows you to pass in multiple classes that define [Verb] methods so you can opt to organize the code that CLAP will invoke in any way that you like. You can invoke this code from a command line application like this: SomeExe UpdateName -customerId:123 -firstName:Jesse -lastName:Taber ‘SomeExe’ in this example just represents the name of .exe that is would be created from our Console application. CLAP then interprets the arguments passed in order to find the method that should be invoked and automatically parses out the parameters that need to be passed in. After a quick spike, I’ve found that invoking the ‘Parser’ class can be done from within the context of a web application just as easily as it can from within the ‘Main’ method entry point of a Console application. There are, however, a few sticking points that I’m working around: Splitting arguments into the ‘args’ array like the command line: When you invoke a standard .NET console application you get the arguments that were passed in by the user split into a handy array (this is the ‘args’ parameter referenced above). Generally speaking they get split by whitespace, but it’s also clever enough to handle things like ignoring whitespace in a phrase that is surrounded by quotes. We’ll need to re-create this logic within our web application so that we can give the ‘args’ value to CLAP just like a console application would. Providing a response to the user: If you were writing a console application, you might just use Console.WriteLine to provide responses to the user as to the progress and eventual outcome of the command. We can’t use Console.WriteLine within a web application, so I’ll need to find another way to provide feedback to the user. Preferably this approach would allow me to use the same handler classes from both a Console application and a web application, so some kind of strategy pattern will likely emerge from this effort. Submitting files: Often an internal tool needs to support doing some kind of operation in bulk, and the easiest way to submit the data needed to support the bulk operation is in a file. Getting the file uploaded and available to the CLAP handler classes will take a little bit of effort. Mimicking the console experience: This isn’t really a requirement so much as a “nice to have”. To start out, the command-line interface in the web application will probably be a single ‘textarea’ control with a button to submit the contents to a handler that will pass it along to CLAP to be parsed and run. I think it would be interesting to use some javascript and CSS trickery to change that page into something with more of a “shell” interface look and feel. I’ll be blogging more about this effort in the future and will include some code snippets (or maybe even a full blown example app) as I progress. I also think that I’ll probably end up either submitting some pull requests to the CLAP project or possibly forking/wrapping it into a more web-friendly package and open sourcing that.

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  • top tweets WebLogic Partner Community – September 2012

    - by JuergenKress
    Send your tweets @wlscommunity #WebLogicCommunity and follow us at http://twitter.com/wlscommunity Oracle Exalogic? VIDEO: Oracle Public Cloud Built on Exalogic!, http://www.youtube.com/watch?v=UGzjDloUw_s&feature=plcp … oracleopenworld #NetBeans Community Day at #JavaOne http://ow.ly/dunFL Oracle Cloud Zone Building an enterprise Cloud? Have Oracle show you the RIGHT way to plan, deploy and monitor enterprise clouds.... http://fb.me/286978S4S OTNArchBeat? Oracle Exalogic X2-2 walk-through with Brad Cameron | @jvzoggel http://pub.vitrue.com/yE7d Oracle Technet? Stash your cash. September OTN Member Offers - discounts on books, more | OTN Blog http://pub.vitrue.com/yTr9 C2B2 Consulting? C2B2 is Speaking at @UKOUG App Server Middleware SIG Meeting 'Real Life #WebLogic Performance Tuning' http://www.c2b2.co.uk/ukoug_application_server_middleware_sig_meeting … @wlscommunity JAXenter.com? From yesterday, @smeyen offers his views on the next generation #Java - do you agree? http://jaxenter.com/next-gen-java-we-don-t-need-another-revolutionary-44334.html … Markus Eisele? Awesome: professor from ITU uploads her programming lectures to #YouTube. Programming classes without having to pay! http://bit.ly/UtkJIW Adam Bien? Real World Java EE 6 Patterns--Rethinking Best Practices Reloaded: A completely rewritten, second, iteration of ... http://bit.ly/Qc3xTH Markus Eisele [blog] #PrimeFaces Push with #Atmosphere on #GlassFish 3.1.2.2 http://goo.gl/fb/jPDzA Lucas Jellema? Forms community event at Oracle Open World - Tuesday, 2nd Oct with the BIG names in Forms - see: http://oracleformsinfo.wordpress.com/2012/08/28/ask-the-product-manager-join-us-at-the-oracle-forms-community-event-at-openworld-2012/ … WebLogic Community WebLogic & Coherence & Cloud presentations for customer meetings http://wp.me/p1LMIb-kw Adam Bien? New Book: Rethinking Best Practices with Java EE 6 is out: http://realworldpatterns.com (fully rewritten, re-edited and reformatted) WebLogic Community? Want to become and WebLogic 12c expert? free WebLogic 12c partner bootcamps &ndash;new locations: Madrid Spain http://wp.me/p1LMIb-kK WebLogic Community? Promote Your WebLogic events at http://oracle.com http://wp.me/p1LMIb-ku OracleBlogs Gartner review Oracle ADF http://ow.ly/1mgkCV Simon Haslam Next #ukoug App Server & MW SIG on 10 Oct: http://www.ukoug.org/events/ukoug-application-server-and-middleware-sig-meeting8/ … Hopefully plenty of good admin stuff! Michel Schildmeijer My book "WebLogic 12c; First look" has been reviewed again..see http://www.amazon.com/review/R28L6E3CC9RPMK/ref=cm_cr_pr_perm?ie=UTF8&ASIN=1849687188&linkCode=&nodeID=&tag= … … Markus Eisele? #Weblogic 11g Interactive Quick Reference Map: http://bit.ly/Ugsq52 #wls #oracle #reference /via @TonyvanEsch Marc? Playing with #syslog server and #weblogic. Is there a simple how-to to configure all the logging from #WLS to #syslog-ng WebLogic Community Java update http://wp.me/p1LMIb-kI WebLogic Community top tweets WebLogic Partner Community &ndash; August 2012 http://wp.me/p1LMIb-kA Andrejus Baranovskis? Oracle University Training: ADF/WebCenter 11g Development in Depth | Andrejus Baranovskis http://fb.me/253ZTS2zp OracleSupport_WLS? How neat is a free tool that allows you to inspect and debug traffic from virtually any application? http://pub.vitrue.com/vXdP WebLogic Community WebLogic Partner Community Newsletter August 2012 http://wp.me/p1LMIb-kn OTNArchBeat Integrating Coherence & Java EE 6 Applications using ActiveCache | Ricardo Ferreira http://pub.vitrue.com/rwGg Adam Bien? Thanks for attending the #javaee #techtalk "Enterprise Java 2.0" I pushed the project and slides to: http://kenai.com/projects/javaee-patterns/sources/hg/show/hacks/techtalk2012?rev=429 … JDeveloper & ADF? How to service-enable Oracle ADF Business Components http://ht.ly/1mcfsZ OracleSupport_WLS? Do you know that #WebLogic 12.1.1.0 is certified for production with JDK 7? @ http://pub.vitrue.com/35Kn Andreas Koop? My latest upload : WebLogic Administration und Deployment mit WLST on @slideshare http://www.slideshare.net/multikoop/weblogic-administration-und-deployment-mit-wlst … OTNArchBeat? Demo for OPN: Oracle Coherence Management with EM Cloud Control 12c http://pub.vitrue.com/reoo Markus Eisele? [blog] Java Champions at #JavaOne 2012 http://goo.gl/fb/Ibb6N #javachampion OracleBlogs Buy This Book!: Oracle Exalogic Elastic Cloud Handbook http://ow.ly/1malM1 WebLogic Community? Coherence Management with EM Cloud Control 12c &ndash;demo for partners http://wp.me/p1LMIb-iE Arun Gupta? Learn how Java can help Internet of Things at Java Embedded at JavaOne: http://bit.ly/POBizh WebLogic Community? Follow WebLogicCommunity on facebook http://www.facebook.com/WebLogicCommunity … #WebLogicCommunity WebLogic Community? Building Java EE in the Cloud–Webcast August 30th 2012 https://weblogiccommunity.wordpress.com/2012/08/27/building-java-ee-in-the-cloudwebcast-august-30th-2012/ … #WebLogicCommunity #Java #oracle #opn WebLogic Community? Call for WebLogic Community newsletter content. Please send @wlscommunity #WebLogicCommunity OracleSupport_WLS? The #weblogic wasp: lots of tips, Q&A and examples http://pub.vitrue.com/v0bw Frank Nimphius? Free ADF Best Practices Webinar by Andrejus Baranovskis for ODTUG (18, 2012 12:00 PM - 1:00 PM EDT) http://bit.ly/OiSWbi ADF Code Corner Webcast- Friday September 14, 8:30 AM - 9.00 AM (CET) - ADF as a basis of Fusion Apps (in English) - with Chris Muir: http://bit.ly/OiQVMb Oracle WebLogic? New blog post: Developing Custom User Principal Object http://pub.vitrue.com/ltam JAX London? Just 4days left to get in on the early bird special, don't miss out!! http://jaxlondon.com/ #JAXLondon #Java WebLogic Community Building Java EE in the Cloud&ndash;Webcast August 30th 2012 http://wp.me/p1LMIb-kE Andrejus Baranovskis? New Record Master-Detail Validation and ADF BC Groovy Use Case http://fb.me/1D2NEIl8g JAX London? Don't miss out!!! Only 6 days left to make use of our early bird offer #JAXLondon #JAVA http://jaxlondon.com/ Michel Schildmeijer Qualogy launches Proof of Concept Center for Oracle Fusion Applications http://www.qualogy.com/qualogy-launches-proof-of-concept-center-for-oracle-fusion-applications/ … via @Qualogy_news OracleSupport_WLS ?Need to troubleshoot redeployment failure in #Weblogic? Check this http://pub.vitrue.com/auhz OracleEnterpriseMgr? Blog : Managing Oracle #Exalogic Elastic #Cloud with Oracle Enterprise Manager Ops Center http://ow.ly/dd40e #em12c ODTUG? Want free advanced technical ADF training?Join @andrejusb for an @odtug webinar! check out his blog for more info http://bit.ly/SvKJDq chriscmuir Oracle Open World 2012 and ADF EMG http://zite.to/QyusZE OTNArchBeat? Boost your infrastructure with Coherence into the Cloud | Nino Guarnacci http://pub.vitrue.com/v3aJ WebLogic Community? Presentations & Training material OFM Summer Camps & Impressions & Feedback http://wp.me/p1LMIb-ks Arun Gupta? Java EE 6 pocket guide by O'Reilly available for pre-order from Amazon: http://amzn.to/O6YyoP and B&N: http://bit.ly/NjWLk1 OTNArchBeat Joining the Existing Cluster in Coherence | A. Fuat Sungur http://pub.vitrue.com/6uLh Andrejus Baranovskis Sample Application for Switching Application Module Data Sources http://fb.me/1PSURUzch OTNArchBeat Oracle WebLogic DevCast: Building Java EE in the Cloud - August 30 - 10am PT/ 1pm ET http://pub.vitrue.com/xXg0 OTNArchBeat? GlassFish Community Event at #javaone - Sept 30 -11am – 1pm -Moscone South. Register Now! http://pub.vitrue.com/p2f5 OracleSupport_WLS? Connecting To HTTPS Site Using Simple Java Program When Using Proxy http://pub.vitrue.com/stVv Michel Schildmeijer? Before you go to #OOW take the sneak preview of WebLogic 12c with you: http://www.qualogy.com/ga-nog-niet-naar-oow-en-neem-mee-weblogic-12c/ … via @Qualogy_news Simon Haslam? Even more great ADF content at #oow2012 this year including a packed ADF EMG day on Sunday: https://blogs.oracle.com/onesizedoesntfitall/entry/the_year_after_the_year … OracleBlogs ExaLogic trainings for partners http://ow.ly/1m6a5D Robin? First presentation on DOAG conference (thanks to @Steffen2042) "Weblogic Server for Dummies". Now I´m pretty excited :) http://www.doag.org/de/events/konferenzen/doag-2012.html … Markus Eisele There is a #facebook page for the upcoming #Java Mission Control (JRockit Mission Control for #Hotspot)! ttp://on.fb.me/Q31oyA Adam Bien? The almost free #javaee workshop in Rapperswil has only 60 registrations so far: http://www.adam-bien.com/roller/abien/entry/enterprise_java_2_0_swiss … What's the problem? :-) WebLogic Community ExaLogic trainings for partners http://wp.me/p1LMIb-iC OracleBlogs How to install Oracle Weblogic Server using Generic Package installer? http://ow.ly/1m5ms7 OracleSupport_WLS #Weblogic Server new blog post - Developing Custom User Principal Object http://pub.vitrue.com/ltam OracleBlogs? Architects and Architecture at JavaOne 2012 http://ow.ly/1m4oS5 WebLogic Community Are you WebLogic or Application Grid Specialized? Do you get Recognized? Get your plaque https://weblogiccommunity.wordpress.com/2012/08/21/plaques-weblogic-application-grid-specialization/ … #WebLogicCommunity #opn WebLogic Community? Plaques WebLogic & Application Grid Specialization http://wp.me/p1LMIb-iA JDeveloper & ADF? First Steps With Oracle Application Testing Suite: Recording a Test With OpenScript http://dlvr.it/222npy WebLogic Partner Community For regular information become a member in the WebLogic Partner Community please visit: http://www.oracle.com/partners/goto/wls-emea ( OPN account required). If you need support with your account please contact the Oracle Partner Business Center. Blog Twitter LinkedIn Mix Forum Wiki Technorati Tags: twitter,WebLogic,WebLogic Community,Oracle,OPN,Jürgen Kress

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  • CodePlex Daily Summary for Sunday, July 14, 2013

    CodePlex Daily Summary for Sunday, July 14, 2013Popular ReleasesVidCoder: 1.4.23: New in 1.4.23 Added French translation. Fixed non-x264 video encoders not sticking in video tab. New in 1.4 Updated HandBrake core to 0.9.9 Blu-ray subtitle (PGS) support Additional framerates: 30, 50, 59.94, 60 Additional sample rates: 8, 11.025, 12 and 16 kHz Additional higher bitrates for audio Same as Source Constant Framerate 24-bit FLAC encoding Added Windows Phone 8 and Apple TV 3 presets Introduced process isolation for encodes. Now if HandBrake crashes, VidCoder will ...Microsoft Ajax Minifier: Microsoft Ajax Minifier 4.96: Fix for issue #19957: EXE should output the name of the file(s) being minified. Discussion #449181: throw a Sev-2 warning when trailing commas are detected on an Array literal. Perfectly legal to do so, but the behavior ends up working differently on different browsers, so throw a cross-browser warning. Add a few more known global names for improved ES6 compatibility update Nuget package to version 2.5 and automatically add the AjaxMin.targets to your project when you update the package...JSLint.NET: JSLint.NET 0.9.1 Beta: Version 0.9.1 Beta includes: JSLint.NET Console: Console help available using the /? switch (or no arguments). See the Console Options page for more. JSLint.NET for Visual Studio: Support linked JSLintNet.json file. More about this file on the JSLint.NET Settings page. Hide un-implemented menu items. Prefix JSLint errors in the task list. JSLint.NET Core: Allow ignoring of individual files in JSLintNet.json.TypePipe: 1.15.2.0 (.NET 4.5): This is build 1.15.2.0 of the TypePipe for .NET 4.5. Find the complete release notes for the build here: Release Notes.re-linq: 1.15.2.0 (.NET 4.5): This is build 1.15.2.0 of re-linq for .NET 4.5. 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If you are coming from earlier versions, make a precautionary backup of your existing website files and database. When installing the update, the database update engine will create the new schema items (if you...Dalmatian Build Script: Dalmatian Build 0.1.3.0: -Minor bug fixes -Added Choose<T> and ChooseYesNo to Console objectPushover.NET: Pushover.NET - Stable Release 10 July 2013: This is the first stable release of Pushover.NET. It includes 14 overloads of the SendNotification method, giving you total flexibility of sending Pushover notifications from your client. Assembly is built to .NET 2.x so it can be called from .NET 2.x, 3.x and 4.x projects. Also available is the Test Harness. This is a small GUI that you can use to test calls to Pushover.NET's main DLL. 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Which are representations of randomly balanced binary trees.ReoScript: JavaScript-like script language engine for .NET application. Easy to plug in .NET program and make API extension for script. SQL Queries: This is for all developers help.SqlSetup: This project create SQL server database automatically. Truco Pythons: Truco Argentino (Argentine truc), is a card game developed in python by Argentine programmers of the UNGS (General Sarmiento National University). WebServer .NET: Projekt zawiera oprogramowanie i zestaw narzedzi do zarzadzania serwerem http. Posiada wiele funkcjonalnosci ulatwiajacych korzystanie i konfigurowanie serwera.workspaces: solr exampleWP8NativeAccess: Win32 API wrappers for Windows Phone 8. Intended to be used in WP8 WinRT apps. Includes FileSystem project.

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  • How to do inclusive range queries when only half-open range is supported (ala SortedMap.subMap)

    - by polygenelubricants
    On SortedMap.subMap This is the API for SortedMap<K,V>.subMap: SortedMap<K,V> subMap(K fromKey, K toKey) : Returns a view of the portion of this map whose keys range from fromKey, inclusive, to toKey, exclusive. This inclusive lower bound, exclusive upper bound combo ("half-open range") is something that is prevalent in Java, and while it does have its benefits, it also has its quirks, as we shall soon see. The following snippet illustrates a simple usage of subMap: static <K,V> SortedMap<K,V> someSortOfSortedMap() { return Collections.synchronizedSortedMap(new TreeMap<K,V>()); } //... SortedMap<Integer,String> map = someSortOfSortedMap(); map.put(1, "One"); map.put(3, "Three"); map.put(5, "Five"); map.put(7, "Seven"); map.put(9, "Nine"); System.out.println(map.subMap(0, 4)); // prints "{1=One, 3=Three}" System.out.println(map.subMap(3, 7)); // prints "{3=Three, 5=Five}" The last line is important: 7=Seven is excluded, due to the exclusive upper bound nature of subMap. Now suppose that we actually need an inclusive upper bound, then we could try to write a utility method like this: static <V> SortedMap<Integer,V> subMapInclusive(SortedMap<Integer,V> map, int from, int to) { return (to == Integer.MAX_VALUE) ? map.tailMap(from) : map.subMap(from, to + 1); } Then, continuing on with the above snippet, we get: System.out.println(subMapInclusive(map, 3, 7)); // prints "{3=Three, 5=Five, 7=Seven}" map.put(Integer.MAX_VALUE, "Infinity"); System.out.println(subMapInclusive(map, 5, Integer.MAX_VALUE)); // {5=Five, 7=Seven, 9=Nine, 2147483647=Infinity} A couple of key observations need to be made: The good news is that we don't care about the type of the values, but... subMapInclusive assumes Integer keys for to + 1 to work. A generic version that also takes e.g. Long keys is not possible (see related questions) Not to mention that for Long, we need to compare against Long.MAX_VALUE instead Overloads for the numeric primitive boxed types Byte, Character, etc, as keys, must all be written individually A special check need to be made for toInclusive == Integer.MAX_VALUE, because +1 would overflow, and subMap would throw IllegalArgumentException: fromKey > toKey This, generally speaking, is an overly ugly and overly specific solution What about String keys? Or some unknown type that may not even be Comparable<?>? So the question is: is it possible to write a general subMapInclusive method that takes a SortedMap<K,V>, and K fromKey, K toKey, and perform an inclusive-range subMap queries? Related questions Are upper bounds of indexed ranges always assumed to be exclusive? Is it possible to write a generic +1 method for numeric box types in Java? On NavigableMap It should be mentioned that there's a NavigableMap.subMap overload that takes two additional boolean variables to signify whether the bounds are inclusive or exclusive. Had this been made available in SortedMap, then none of the above would've even been asked. So working with a NavigableMap<K,V> for inclusive range queries would've been ideal, but while Collections provides utility methods for SortedMap (among other things), we aren't afforded the same luxury with NavigableMap. Related questions Writing a synchronized thread-safety wrapper for NavigableMap On API providing only exclusive upper bound range queries Does this highlight a problem with exclusive upper bound range queries? How were inclusive range queries done in the past when exclusive upper bound is the only available functionality?

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  • Clean Code Developer & Certification in IT - MSCC 21.09.2013

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

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  • Windows Azure Mobile Services: New support for iOS apps, Facebook/Twitter/Google identity, Emails, SMS, Blobs, Service Bus and more

    - by ScottGu
    A few weeks ago I blogged about Windows Azure Mobile Services - a new capability in Windows Azure that makes it incredibly easy to connect your client and mobile applications to a scalable cloud backend. Earlier today we delivered a number of great improvements to Windows Azure Mobile Services.  New features include: iOS support – enabling you to connect iPhone and iPad apps to Mobile Services Facebook, Twitter, and Google authentication support with Mobile Services Blob, Table, Queue, and Service Bus support from within your Mobile Service Sending emails from your Mobile Service (in partnership with SendGrid) Sending SMS messages from your Mobile Service (in partnership with Twilio) Ability to deploy mobile services in the West US region All of these improvements are now live in production and available to start using immediately. Below are more details on them: iOS Support This week we delivered initial support for connecting iOS based devices (including iPhones and iPads) to Windows Azure Mobile Services.  Like the rest of our Windows Azure SDK, we are delivering the native iOS libraries to enable this under an open source (Apache 2.0) license on GitHub.  We’re excited to get your feedback on this new library through our forum and GitHub issues list, and we welcome contributions to the SDK. To create a new iOS app or connect an existing iOS app to your Mobile Service, simply select the “iOS” tab within the Quick Start view of a Mobile Service within the Windows Azure Portal – and then follow either the “Create a new iOS app” or “Connect to an existing iOS app” link below it: Clicking either of these links will expand and display step-by-step instructions for how to build an iOS application that connects with your Mobile Service: Read this getting started tutorial to walkthrough how you can build (in less than 5 minutes) a simple iOS “Todo List” app that stores data in Windows Azure.  Then follow the below tutorials to explore how to use the iOS client libraries to store data and authenticate users. Get Started with data in Mobile Services for iOS Get Started with authentication in Mobile Services for iOS Facebook, Twitter, and Google Authentication Support Our initial preview of Mobile Services supported the ability to authenticate users of mobile apps using Microsoft Accounts (formerly called Windows Live ID accounts).  This week we are adding the ability to also authenticate users using Facebook, Twitter, and Google credentials.  These are now supported with both Windows 8 apps as well as iOS apps (and a single app can support multiple forms of identity simultaneously – so you can offer your users a choice of how to login). The below tutorials walkthrough how to register your Mobile Service with an identity provider: How to register your app with Microsoft Account How to register your app with Facebook How to register your app with Twitter How to register your app with Google The tutorials above walkthrough how to obtain a client ID and a secret key from the identity provider. You can then click on the “Identity” tab of your Mobile Service (within the Windows Azure Portal) and save these values to enable server-side authentication with your Mobile Service: You can then write code within your client or mobile app to authenticate your users to the Mobile Service.  For example, below is the code you would write to have them login to the Mobile Service using their Facebook credentials: Windows Store App (using C#): var user = await App.MobileService                     .LoginAsync(MobileServiceAuthenticationProvider.Facebook); iOS app (using Objective C): UINavigationController *controller = [self.todoService.client     loginViewControllerWithProvider:@"facebook"     completion:^(MSUser *user, NSError *error) {        //... }]; Learn more about authenticating Mobile Services using Microsoft Account, Facebook, Twitter, and Google from these tutorials: Get started with authentication in Mobile Services for Windows Store (C#) Get started with authentication in Mobile Services for Windows Store (JavaScript) Get started with authentication in Mobile Services for iOS Using Windows Azure Blob, Tables and ServiceBus with your Mobile Services Mobile Services provide a simple but powerful way to add server logic using server scripts. These scripts are associated with the individual CRUD operations on your mobile service’s tables. Server scripts are great for data validation, custom authorization logic (e.g. does this user participate in this game session), augmenting CRUD operations, sending push notifications, and other similar scenarios.   Server scripts are written in JavaScript and are executed in a secure server-side scripting environment built using Node.js.  You can edit these scripts and save them on the server directly within the Windows Azure Portal: In this week’s release we have added the ability to work with other Windows Azure services from your Mobile Service server scripts.  This is supported using the existing “azure” module within the Windows Azure SDK for Node.js.  For example, the below code could be used in a Mobile Service script to obtain a reference to a Windows Azure Table (after which you could query it or insert data into it):     var azure = require('azure');     var tableService = azure.createTableService("<< account name >>",                                                 "<< access key >>"); Follow the tutorials on the Windows Azure Node.js dev center to learn more about working with Blob, Tables, Queues and Service Bus using the azure module. Sending emails from your Mobile Service In this week’s release we have also added the ability to easily send emails from your Mobile Service, building on our partnership with SendGrid. Whether you want to add a welcome email upon successful user registration, or make your app alert you of certain usage activities, you can do this now by sending email from Mobile Services server scripts. To get started, sign up for SendGrid account at http://sendgrid.com . Windows Azure customers receive a special offer of 25,000 free emails per month from SendGrid. To sign-up for this offer, or get more information, please visit http://www.sendgrid.com/azure.html . One you signed up, you can add the following script to your Mobile Service server scripts to send email via SendGrid service:     var sendgrid = new SendGrid('<< account name >>', '<< password >>');       sendgrid.send({         to: '<< enter email address here >>',         from: '<< enter from address here >>',         subject: 'New to-do item',         text: 'A new to-do was added: ' + item.text     }, function (success, message) {         if (!success) {             console.error(message);         }     }); Follow the Send email from Mobile Services with SendGrid tutorial to learn more. Sending SMS messages from your Mobile Service SMS is a key communication medium for mobile apps - it comes in handy if you want your app to send users a confirmation code during registration, allow your users to invite their friends to install your app or reach out to mobile users without a smartphone. Using Mobile Service server scripts and Twilio’s REST API, you can now easily send SMS messages to your app.  To get started, sign up for Twilio account. Windows Azure customers receive 1000 free text messages when using Twilio and Windows Azure together. Once signed up, you can add the following to your Mobile Service server scripts to send SMS messages:     var httpRequest = require('request');     var account_sid = "<< account SID >>";     var auth_token = "<< auth token >>";       // Create the request body     var body = "From=" + from + "&To=" + to + "&Body=" + message;       // Make the HTTP request to Twilio     httpRequest.post({         url: "https://" + account_sid + ":" + auth_token +              "@api.twilio.com/2010-04-01/Accounts/" + account_sid + "/SMS/Messages.json",         headers: { 'content-type': 'application/x-www-form-urlencoded' },         body: body     }, function (err, resp, body) {         console.log(body);     }); I’m excited to be speaking at the TwilioCon conference this week, and will be showcasing some of the cool scenarios you can now enable with Twilio and Windows Azure Mobile Services. Mobile Services availability in West US region Our initial preview of Windows Azure Mobile Services was only supported in the US East region of Windows Azure.  As with every Windows Azure service, overtime we will extend Mobile Services to all Windows Azure regions. With this week’s preview update we’ve added support so that you can now create your Mobile Service in the West US region as well: Summary The above features are all now live in production and are available to use immediately.  If you don’t already have a Windows Azure account, you can sign-up for a free trial and start using Mobile Services today. Visit the Windows Azure Mobile Developer Center to learn more about how to build apps with Mobile Services. We’ll have even more new features and enhancements coming later this week – including .NET 4.5 support for Windows Azure Web Sites.  Keep an eye out on my blog for details as new features become available. Hope this helps, Scott P.S. In addition to blogging, I am also now using Twitter for quick updates and to share links. Follow me at: twitter.com/scottgu

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  • The Java Specialist: An Interview with Java Champion Heinz Kabutz

    - by Janice J. Heiss
    Dr. Heinz Kabutz is well known for his Java Specialists’ Newsletter, initiated in November 2000, where he displays his acute grasp of the intricacies of the Java platform for an estimated 70,000 readers; for his work as a consultant; and for his workshops and trainings at his home on the Island of Crete where he has lived since 2006 -- where he is known to curl up on the beach with his laptop to hack away, in between dips in the Mediterranean. Kabutz was born of German parents and raised in Cape Town, South Africa, where he developed a love of programming in junior high school through his explorations on a ZX Spectrum computer. He received a B.S. from the University of Cape Town, and at 25, a Ph.D., both in computer science. He will be leading a two-hour hands-on lab session, HOL6500 – “Finding and Solving Java Deadlocks,” at this year’s JavaOne that will explore what causes deadlocks and how to solve them. Q: Tell us about your JavaOne plans.A: I am arriving on Sunday evening and have just one hands-on-lab to do on Monday morning. This is the first time that a non-Oracle team is doing a HOL at JavaOne under Oracle's stewardship and we are all a bit nervous about how it will turn out. Oracle has been immensely helpful in getting us set up. I have a great team helping me: Kirk Pepperdine, Dario Laverde, Benjamin Evans and Martijn Verburg from jClarity, Nathan Reynolds from Oracle, Henri Tremblay of OCTO Technology and Jeff Genender of Savoir Technologies. Monday will be hard work, but after that, I will hopefully get to network with fellow Java experts, attend interesting sessions and just enjoy San Francisco. Oh, and my kids have already given me a shopping list of things to get, like a GoPro Hero 2 dive housing for shooting those nice videos of Crete. (That's me at the beginning diving down.) Q: What sessions are you attending that we should know about?A: Sometimes the most unusual sessions are the best. I avoid the "big names". They often are spread too thin with all their sessions, which makes it difficult for them to deliver what I would consider deep content. I also avoid entertainers who might be good at presenting but who do not say that much.In 2010, I attended a session by Vladimir Yaroslavskiy where he talked about sorting. Although he struggled to speak English, what he had to say was spectacular. There was hardly anybody in the room, having not heard of Vladimir before. To me that was the highlight of 2010. Funnily enough, he was supposed to speak with Joshua Bloch, but if you remember, Google cancelled. If Bloch has been there, the room would have been packed to capacity.Q: Give us an update on the Java Specialists’ Newsletter.A: The Java Specialists' Newsletter continues being read by an elite audience around the world. The apostrophe in the name is significant.  It is a newsletter for Java specialists. When I started it twelve years ago, I was trying to find non-obvious things in Java to write about. Things that would be interesting to an advanced audience.As an April Fool's joke, I told my readers in Issue 44 that subscribing would remain free, but that they would have to pay US$5 to US$7 depending on their geographical location. I received quite a few angry emails from that one. I would have not earned that much from unsubscriptions. Most readers stay for a very long time.After Oracle bought Sun, the Java community held its breath for about two years whilst Oracle was figuring out what to do with Java. For a while, we were quite concerned that there was not much progress shown by Oracle. My newsletter still continued, but it was quite difficult finding new things to write about. We have probably about 70,000 readers, which is quite a small number for a Java publication. However, our readers are the top in the Java industry. So I don't mind having "only" 70000 readers, as long as they are the top 0.7%.Java concurrency is a very important topic that programmers think they should know about, but often neglect to fully understand. I continued writing about that and made some interesting discoveries. For example, in Issue 165, I showed how we can get thread starvation with the ReadWriteLock. This was a bug in Java 5, which was corrected in Java 6, but perhaps a bit too much. Whereas we could get starvation of writers in Java 5, in Java 6 we could now get starvation of readers. All of these interesting findings make their way into my courseware to help companies avoid these pitfalls.Another interesting discovery was how polymorphism works in the Server HotSpot compiler in Issue 157 and Issue 158. HotSpot can inline methods from interfaces that have only one implementation class in the JVM. When a new subclass is instantiated and called for the first time, the JVM will undo the previous optimization and re-optimize differently.Here is a little memory puzzle for your readers: public class JavaMemoryPuzzle {  private final int dataSize =      (int) (Runtime.getRuntime().maxMemory() * 0.6);  public void f() {    {      byte[] data = new byte[dataSize];    }    byte[] data2 = new byte[dataSize];  }  public static void main(String[] args) {    JavaMemoryPuzzle jmp = new JavaMemoryPuzzle();    jmp.f();  }}When you run this you will always get an OutOfMemoryError, even though the local variable data is no longer visible outside of the code block.So here comes the puzzle, that I'd like you to ponder a bit. If you very politely ask the VM to release memory, then you don't get an OutOfMemoryError: public class JavaMemoryPuzzlePolite {  private final int dataSize =      (int) (Runtime.getRuntime().maxMemory() * 0.6);  public void f() {    {      byte[] data = new byte[dataSize];    }    for(int i=0; i<10; i++) {      System.out.println("Please be so kind and release memory");    }    byte[] data2 = new byte[dataSize];  }  public static void main(String[] args) {    JavaMemoryPuzzlePolite jmp = new JavaMemoryPuzzlePolite();    jmp.f();    System.out.println("No OutOfMemoryError");  }}Why does this work? When I published this in my newsletter, I received over 400 emails from excited readers around the world, most of whom sent me the wrong explanation. After the 300th wrong answer, my replies became unfortunately a bit curt. Have a look at Issue 174 for a detailed explanation, but before you do, put on your thinking caps and try to figure it out yourself. Q: What do you think Java developers should know that they currently do not know?A: They should definitely get to know more about concurrency. It is a tough subject that most programmers try to avoid. Unfortunately we do come in contact with it. And when we do, we need to know how to protect ourselves and how to solve tricky system errors.Knowing your IDE is also useful. Most IDEs have a ton of shortcuts, which can make you a lot more productive in moving code around. Another thing that is useful is being able to read GC logs. Kirk Pepperdine has a great talk at JavaOne that I can recommend if you want to learn more. It's this: CON5405 – “Are Your Garbage Collection Logs Speaking to You?” Q: What are you looking forward to in Java 8?A: I'm quite excited about lambdas, though I must confess that I have not studied them in detail yet. Maurice Naftalin's Lambda FAQ is quite a good start to document what you can do with them. I'm looking forward to finding all the interesting bugs that we will now get due to lambdas obscuring what is really going on underneath, just like we had with generics.I am quite impressed with what the team at Oracle did with OpenJDK's performance. A lot of the benchmarks now run faster.Hopefully Java 8 will come with JSR 310, the Date and Time API. It still boggles my mind that such an important API has been left out in the cold for so long.What I am not looking forward to is losing perm space. Even though some systems run out of perm space, at least the problem is contained and they usually manage to work around it. In most cases, this is due to a memory leak in that region of memory. Once they bundle perm space with the old generation, I predict that memory leaks in perm space will be harder to find. More contracts for us, but also more pain for our customers. Originally published on blogs.oracle.com/javaone.

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  • The Java Specialist: An Interview with Java Champion Heinz Kabutz

    - by Janice J. Heiss
    Dr. Heinz Kabutz is well known for his Java Specialists’ Newsletter, initiated in November 2000, where he displays his acute grasp of the intricacies of the Java platform for an estimated 70,000 readers; for his work as a consultant; and for his workshops and trainings at his home on the Island of Crete where he has lived since 2006 -- where he is known to curl up on the beach with his laptop to hack away, in between dips in the Mediterranean. Kabutz was born of German parents and raised in Cape Town, South Africa, where he developed a love of programming in junior high school through his explorations on a ZX Spectrum computer. He received a B.S. from the University of Cape Town, and at 25, a Ph.D., both in computer science. He will be leading a two-hour hands-on lab session, HOL6500 – “Finding and Solving Java Deadlocks,” at this year’s JavaOne that will explore what causes deadlocks and how to solve them. Q: Tell us about your JavaOne plans.A: I am arriving on Sunday evening and have just one hands-on-lab to do on Monday morning. This is the first time that a non-Oracle team is doing a HOL at JavaOne under Oracle's stewardship and we are all a bit nervous about how it will turn out. Oracle has been immensely helpful in getting us set up. I have a great team helping me: Kirk Pepperdine, Dario Laverde, Benjamin Evans and Martijn Verburg from jClarity, Nathan Reynolds from Oracle, Henri Tremblay of OCTO Technology and Jeff Genender of Savoir Technologies. Monday will be hard work, but after that, I will hopefully get to network with fellow Java experts, attend interesting sessions and just enjoy San Francisco. Oh, and my kids have already given me a shopping list of things to get, like a GoPro Hero 2 dive housing for shooting those nice videos of Crete. (That's me at the beginning diving down.) Q: What sessions are you attending that we should know about?A: Sometimes the most unusual sessions are the best. I avoid the "big names". They often are spread too thin with all their sessions, which makes it difficult for them to deliver what I would consider deep content. I also avoid entertainers who might be good at presenting but who do not say that much.In 2010, I attended a session by Vladimir Yaroslavskiy where he talked about sorting. Although he struggled to speak English, what he had to say was spectacular. There was hardly anybody in the room, having not heard of Vladimir before. To me that was the highlight of 2010. Funnily enough, he was supposed to speak with Joshua Bloch, but if you remember, Google cancelled. If Bloch has been there, the room would have been packed to capacity.Q: Give us an update on the Java Specialists’ Newsletter.A: The Java Specialists' Newsletter continues being read by an elite audience around the world. The apostrophe in the name is significant.  It is a newsletter for Java specialists. When I started it twelve years ago, I was trying to find non-obvious things in Java to write about. Things that would be interesting to an advanced audience.As an April Fool's joke, I told my readers in Issue 44 that subscribing would remain free, but that they would have to pay US$5 to US$7 depending on their geographical location. I received quite a few angry emails from that one. I would have not earned that much from unsubscriptions. Most readers stay for a very long time.After Oracle bought Sun, the Java community held its breath for about two years whilst Oracle was figuring out what to do with Java. For a while, we were quite concerned that there was not much progress shown by Oracle. My newsletter still continued, but it was quite difficult finding new things to write about. We have probably about 70,000 readers, which is quite a small number for a Java publication. However, our readers are the top in the Java industry. So I don't mind having "only" 70000 readers, as long as they are the top 0.7%.Java concurrency is a very important topic that programmers think they should know about, but often neglect to fully understand. I continued writing about that and made some interesting discoveries. For example, in Issue 165, I showed how we can get thread starvation with the ReadWriteLock. This was a bug in Java 5, which was corrected in Java 6, but perhaps a bit too much. Whereas we could get starvation of writers in Java 5, in Java 6 we could now get starvation of readers. All of these interesting findings make their way into my courseware to help companies avoid these pitfalls.Another interesting discovery was how polymorphism works in the Server HotSpot compiler in Issue 157 and Issue 158. HotSpot can inline methods from interfaces that have only one implementation class in the JVM. When a new subclass is instantiated and called for the first time, the JVM will undo the previous optimization and re-optimize differently.Here is a little memory puzzle for your readers: public class JavaMemoryPuzzle {  private final int dataSize =      (int) (Runtime.getRuntime().maxMemory() * 0.6);  public void f() {    {      byte[] data = new byte[dataSize];    }    byte[] data2 = new byte[dataSize];  }  public static void main(String[] args) {    JavaMemoryPuzzle jmp = new JavaMemoryPuzzle();    jmp.f();  }}When you run this you will always get an OutOfMemoryError, even though the local variable data is no longer visible outside of the code block.So here comes the puzzle, that I'd like you to ponder a bit. If you very politely ask the VM to release memory, then you don't get an OutOfMemoryError: public class JavaMemoryPuzzlePolite {  private final int dataSize =      (int) (Runtime.getRuntime().maxMemory() * 0.6);  public void f() {    {      byte[] data = new byte[dataSize];    }    for(int i=0; i<10; i++) {      System.out.println("Please be so kind and release memory");    }    byte[] data2 = new byte[dataSize];  }  public static void main(String[] args) {    JavaMemoryPuzzlePolite jmp = new JavaMemoryPuzzlePolite();    jmp.f();    System.out.println("No OutOfMemoryError");  }}Why does this work? When I published this in my newsletter, I received over 400 emails from excited readers around the world, most of whom sent me the wrong explanation. After the 300th wrong answer, my replies became unfortunately a bit curt. Have a look at Issue 174 for a detailed explanation, but before you do, put on your thinking caps and try to figure it out yourself. Q: What do you think Java developers should know that they currently do not know?A: They should definitely get to know more about concurrency. It is a tough subject that most programmers try to avoid. Unfortunately we do come in contact with it. And when we do, we need to know how to protect ourselves and how to solve tricky system errors.Knowing your IDE is also useful. Most IDEs have a ton of shortcuts, which can make you a lot more productive in moving code around. Another thing that is useful is being able to read GC logs. Kirk Pepperdine has a great talk at JavaOne that I can recommend if you want to learn more. It's this: CON5405 – “Are Your Garbage Collection Logs Speaking to You?” Q: What are you looking forward to in Java 8?A: I'm quite excited about lambdas, though I must confess that I have not studied them in detail yet. Maurice Naftalin's Lambda FAQ is quite a good start to document what you can do with them. I'm looking forward to finding all the interesting bugs that we will now get due to lambdas obscuring what is really going on underneath, just like we had with generics.I am quite impressed with what the team at Oracle did with OpenJDK's performance. A lot of the benchmarks now run faster.Hopefully Java 8 will come with JSR 310, the Date and Time API. It still boggles my mind that such an important API has been left out in the cold for so long.What I am not looking forward to is losing perm space. Even though some systems run out of perm space, at least the problem is contained and they usually manage to work around it. In most cases, this is due to a memory leak in that region of memory. Once they bundle perm space with the old generation, I predict that memory leaks in perm space will be harder to find. More contracts for us, but also more pain for our customers.

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  • How to parse HTML with TouchXML or some other alternative.

    - by 0SX
    Hi, I'm trying to parse the HTML presented below with TouchXML but it keeps crashing when I try to extract certain attributes. I'm totally new to the parser world so I apologize for being a complete idiot. I need help to parse this HTML. What I'm trying to accomplish is to parse each attribute and value or what not and copy them to a string. I've been trying to find a good parser to parse HTML and I believe TouchXML is the best I've seen because of Tidy. Speaking of Tidy, How could I run this HTML through Tidy first then parse it? I'm not sure how to do this. Here is the code that I have so far that doesn't work due to it's not pulling everything I need from the HTML. Any help or advice would be much appreciated. Thanks My current code: NSMutableArray *res = [[NSMutableArray alloc] init]; // using local resource file NSString *XMLPath = [[[NSBundle mainBundle] resourcePath] stringByAppendingPathComponent:@"example.html"]; NSData *XMLData = [NSData dataWithContentsOfFile:XMLPath]; CXMLDocument *doc = [[[CXMLDocument alloc] initWithData:XMLData options:0 error:nil] autorelease]; NSArray *nodes = NULL; nodes = [doc nodesForXPath:@"//div" error:nil]; for (CXMLElement *node in nodes) { NSMutableDictionary *item = [[NSMutableDictionary alloc] init]; [item setObject:[[node attributeForName:@"id"] stringValue] forKey:@"id"]; [res addObject:item]; [item release]; } NSLog(@"%@", res); [res release]; HTML file that needs to be parsed: <html> <head> <base target="_blank" /> </head> <body style="margin:2;"> <div id="group"> <div id="groupURL"><a href="http://www.example.com/groups">Group URL</a></div> <img id="grouplogo" src="http://images.example.com/groups/image.png" /> <div id="groupcomputer"><a href="http://www.example.com/groups/page" title="Group Title">Group title this would be here</a></div> <div id="groupinfos"> <div id="groupinfo-l">Person</div><div id="groupinfo-r">Ralph</div> <div id="groupinfo-l">Years</div><div id="groupinfo-r">4 years</div> <div id="groupinfo-l">Salary</div><div id="groupinfo-r">100K</div> <div id="groupinfo-l">Other</div><div id="groupoth" style="width:15px">other info</div> </body> </html> EDIT: I could use Element Parser but I need to know how to extract the Person's Name from the following example which would be Ralph in this case. <div id="groupinfo-l">Person</div><div id="groupinfo-r">Ralph</div>

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  • Where'd My Data Go? (and/or...How Do I Get Rid of It?)

    - by David Paquette
    Want to get a better idea of how cascade deletes work in Entity Framework Code First scenarios? Want to see it in action? Stick with us as we quickly demystify what happens when you tell your data context to nuke a parent entity. This post is authored by Calgary .NET User Group Leader David Paquette with help from Microsoft MVP in Asp.Net James Chambers. We got to spend a great week back in March at Prairie Dev Con West, chalk full of sessions, presentations, workshops, conversations and, of course, questions.  One of the questions that came up during my session: "How does Entity Framework Code First deal with cascading deletes?". James and I had different thoughts on what the default was, if it was different from SQL server, if it was the same as EF proper and if there was a way to override whatever the default was.  So we built a set of examples and figured out that the answer is simple: it depends.  (Download Samples) Consider the example of a hockey league. You have several different entities in the league including games, teams that play the games and players that make up the teams. Each team also has a mascot.  If you delete a team, we need a couple of things to happen: The team, games and mascot will be deleted, and The players for that team will remain in the league (and therefore the database) but they should no longer be assigned to a team. So, let's make this start to come together with a look at the default behaviour in SQL when using an EDMX-driven project. The Reference – Understanding EF's Behaviour with an EDMX/DB First Approach First up let’s take a look at the DB first approach.  In the database, we defined 4 tables: Teams, Players, Mascots, and Games.  We also defined 4 foreign keys as follows: Players.Team_Id (NULL) –> Teams.Id Mascots.Id (NOT NULL) –> Teams.Id (ON DELETE CASCADE) Games.HomeTeam_Id (NOT NULL) –> Teams.Id Games.AwayTeam_Id (NOT NULL) –> Teams.Id Note that by specifying ON DELETE CASCADE for the Mascots –> Teams foreign key, the database will automatically delete the team’s mascot when the team is deleted.  While we want the same behaviour for the Games –> Teams foreign keys, it is not possible to accomplish this using ON DELETE CASCADE in SQL Server.  Specifying a ON DELETE CASCADE on these foreign keys would cause a circular reference error: The series of cascading referential actions triggered by a single DELETE or UPDATE must form a tree that contains no circular references. No table can appear more than one time in the list of all cascading referential actions that result from the DELETE or UPDATE – MSDN When we create an entity data model from the above database, we get the following:   In order to get the Games to be deleted when the Team is deleted, we need to specify End1 OnDelete action of Cascade for the HomeGames and AwayGames associations.   Now, we have an Entity Data Model that accomplishes what we set out to do.  One caveat here is that Entity Framework will only properly handle the cascading delete when the the players and games for the team have been loaded into memory.  For a more detailed look at Cascade Delete in EF Database First, take a look at this blog post by Alex James.   Building The Same Sample with EF Code First Next, we're going to build up the model with the code first approach.  EF Code First is defined on the Ado.Net team blog as such: Code First allows you to define your model using C# or VB.Net classes, optionally additional configuration can be performed using attributes on your classes and properties or by using a Fluent API. Your model can be used to generate a database schema or to map to an existing database. Entity Framework Code First follows some conventions to determine when to cascade delete on a relationship.  More details can be found on MSDN: If a foreign key on the dependent entity is not nullable, then Code First sets cascade delete on the relationship. If a foreign key on the dependent entity is nullable, Code First does not set cascade delete on the relationship, and when the principal is deleted the foreign key will be set to null. The multiplicity and cascade delete behavior detected by convention can be overridden by using the fluent API. For more information, see Configuring Relationships with Fluent API (Code First). Our DbContext consists of 4 DbSets: public DbSet<Team> Teams { get; set; } public DbSet<Player> Players { get; set; } public DbSet<Mascot> Mascots { get; set; } public DbSet<Game> Games { get; set; } When we set the Mascot –> Team relationship to required, Entity Framework will automatically delete the Mascot when the Team is deleted.  This can be done either using the [Required] data annotation attribute, or by overriding the OnModelCreating method of your DbContext and using the fluent API. Data Annotations: public class Mascot { public int Id { get; set; } public string Name { get; set; } [Required] public virtual Team Team { get; set; } } Fluent API: protected override void OnModelCreating(DbModelBuilder modelBuilder) { modelBuilder.Entity<Mascot>().HasRequired(m => m.Team); } The Player –> Team relationship is automatically handled by the Code First conventions. When a Team is deleted, the Team property for all the players on that team will be set to null.  No additional configuration is required, however all the Player entities must be loaded into memory for the cascading to work properly. The Game –> Team relationship causes some grief in our Code First example.  If we try setting the HomeTeam and AwayTeam relationships to required, Entity Framework will attempt to set On Cascade Delete for the HomeTeam and AwayTeam foreign keys when creating the database tables.  As we saw in the database first example, this causes a circular reference error and throws the following SqlException: Introducing FOREIGN KEY constraint 'FK_Games_Teams_AwayTeam_Id' on table 'Games' may cause cycles or multiple cascade paths. Specify ON DELETE NO ACTION or ON UPDATE NO ACTION, or modify other FOREIGN KEY constraints. Could not create constraint. To solve this problem, we need to disable the default cascade delete behaviour using the fluent API: protected override void OnModelCreating(DbModelBuilder modelBuilder) { modelBuilder.Entity<Mascot>().HasRequired(m => m.Team); modelBuilder.Entity<Team>() .HasMany(t => t.HomeGames) .WithRequired(g => g.HomeTeam) .WillCascadeOnDelete(false); modelBuilder.Entity<Team>() .HasMany(t => t.AwayGames) .WithRequired(g => g.AwayTeam) .WillCascadeOnDelete(false); base.OnModelCreating(modelBuilder); } Unfortunately, this means we need to manually manage the cascade delete behaviour.  When a Team is deleted, we need to manually delete all the home and away Games for that Team. foreach (Game awayGame in jets.AwayGames.ToArray()) { entities.Games.Remove(awayGame); } foreach (Game homeGame in homeGames) { entities.Games.Remove(homeGame); } entities.Teams.Remove(jets); entities.SaveChanges();   Overriding the Defaults – When and How To As you have seen, the default behaviour of Entity Framework Code First can be overridden using the fluent API.  This can be done by overriding the OnModelCreating method of your DbContext, or by creating separate model override files for each entity.  More information is available on MSDN.   Going Further These were simple examples but they helped us illustrate a couple of points. First of all, we were able to demonstrate the default behaviour of Entity Framework when dealing with cascading deletes, specifically how entity relationships affect the outcome. Secondly, we showed you how to modify the code and control the behaviour to get the outcome you're looking for. Finally, we showed you how easy it is to explore this kind of thing, and we're hoping that you get a chance to experiment even further. For example, did you know that: Entity Framework Code First also works seamlessly with SQL Azure (MSDN) Database creation defaults can be overridden using a variety of IDatabaseInitializers  (Understanding Database Initializers) You can use Code Based migrations to manage database upgrades as your model continues to evolve (MSDN) Next Steps There's no time like the present to start the learning, so here's what you need to do: Get up-to-date in Visual Studio 2010 (VS2010 | SP1) or Visual Studio 2012 (VS2012) Build yourself a project to try these concepts out (or download the sample project) Get into the community and ask questions! There are a ton of great resources out there and community members willing to help you out (like these two guys!). Good luck! About the Authors David Paquette works as a lead developer at P2 Energy Solutions in Calgary, Alberta where he builds commercial software products for the energy industry.  Outside of work, David enjoys outdoor camping, fishing, and skiing. David is also active in the software community giving presentations both locally and at conferences. David also serves as the President of Calgary .Net User Group. James Chambers crafts software awesomeness with an incredible team at LogiSense Corp, based in Cambridge, Ontario. A husband, father and humanitarian, he is currently residing in the province of Manitoba where he resists the urge to cheer for the Jets and maintains he allegiance to the Calgary Flames. When he's not active with the family, outdoors or volunteering, you can find James speaking at conferences and user groups across the country about web development and related technologies.

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  • Minimum-Waste Print Job Grouping Algorithm?

    - by Matt Mc
    I work at a publishing house and I am setting up one of our presses for "ganging", in other words, printing multiple jobs simultaneously. Given that different print jobs can have different quantities, and anywhere from 1 to 20 jobs might need to be considered at a time, the problem would be to determine which jobs to group together to minimize waste (waste coming from over-printing on smaller-quantity jobs in a given set, that is). Given the following stable data: All jobs are equal in terms of spatial size--placement on paper doesn't come into consideration. There are three "lanes", meaning that three jobs can be printed simultaneously. Ideally, each lane has one job. Part of the problem is minimizing how many lanes each job is run on. If necessary, one job could be run on two lanes, with a second job on the third lane. The "grouping" waste from a given set of jobs (let's say the quantities of them are x, y and z) would be the highest number minus the two lower numbers. So if x is the higher number, the grouping waste would be (x - y) + (x - z). Otherwise stated, waste is produced by printing job Y and Z (in excess of their quantities) up to the quantity of X. The grouping waste would be a qualifier for the given set, meaning it could not exceed a certain quantity or the job would simply be printed alone. So the question is stated: how to determine which sets of jobs are grouped together, out of any given number of jobs, based on the qualifiers of 1) Three similar quantities OR 2) Two quantities where one is approximately double the other, AND with the aim of minimal total grouping waste across the various sets. (Edit) Quantity Information: Typical job quantities can be from 150 to 350 on foreign languages, or 500 to 1000 on English print runs. This data can be used to set up some scenarios for an algorithm. For example, let's say you had 5 jobs: 1000, 500, 500, 450, 250 By looking at it, I can see a couple of answers. Obviously (1000/500/500) is not efficient as you'll have a grouping waste of 1000. (500/500/450) is better as you'll have a waste of 50, but then you run (1000) and (250) alone. But you could also run (1000/500) with 1000 on two lanes, (500/250) with 500 on two lanes and then (450) alone. In terms of trade-offs for lane minimization vs. wastage, we could say that any grouping waste over 200 is excessive. (End Edit) ...Needless to say, quite a problem. (For me.) I am a moderately skilled programmer but I do not have much familiarity with algorithms and I am not fully studied in the mathematics of the area. I'm I/P writing a sort of brute-force program that simply tries all options, neglecting any option tree that seems to have excessive grouping waste. However, I can't help but hope there's an easier and more efficient method. I've looked at various websites trying to find out more about algorithms in general and have been slogging my way through the symbology, but it's slow going. Unfortunately, Wikipedia's articles on the subject are very cross-dependent and it's difficult to find an "in". The only thing I've been able to really find would seem to be a definition of the rough type of algorithm I need: "Exclusive Distance Clustering", one-dimensionally speaking. I did look at what seems to be the popularly referred-to algorithm on this site, the Bin Packing one, but I was unable to see exactly how it would work with my problem. Any help is appreciated. :)

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  • Applications: The mathematics of movement, Part 1

    - by TechTwaddle
    Before you continue reading this post, a suggestion; if you haven’t read “Programming Windows Phone 7 Series” by Charles Petzold, go read it. Now. If you find 150+ pages a little too long, at least go through Chapter 5, Principles of Movement, especially the section “A Brief Review of Vectors”. This post is largely inspired from this chapter. At this point I assume you know what vectors are, how they are represented using the pair (x, y), what a unit vector is, and given a vector how you would normalize the vector to get a unit vector. Our task in this post is simple, a marble is drawn at a point on the screen, the user clicks at a random point on the device, say (destX, destY), and our program makes the marble move towards that point and stop when it is reached. The tricky part of this task is the word “towards”, it adds a direction to our problem. Making a marble bounce around the screen is simple, all you have to do is keep incrementing the X and Y co-ordinates by a certain amount and handle the boundary conditions. Here, however, we need to find out exactly how to increment the X and Y values, so that the marble appears to move towards the point where the user clicked. And this is where vectors can be so helpful. The code I’ll show you here is not ideal, we’ll be working with C# on Windows Mobile 6.x, so there is no built-in vector class that I can use, though I could have written one and done all the math inside the class. I think it is trivial to the actual problem that we are trying to solve and can be done pretty easily once you know what’s going on behind the scenes. In other words, this is an excuse for me being lazy. The first approach, uses the function Atan2() to solve the “towards” part of the problem. Atan2() takes a point (x, y) as input, Atan2(y, x), note that y goes first, and then it returns an angle in radians. What angle you ask. Imagine a line from the origin (0, 0), to the point (x, y). The angle which Atan2 returns is the angle the positive X-axis makes with that line, measured clockwise. The figure below makes it clear, wiki has good details about Atan2(), give it a read. The pair (x, y) also denotes a vector. A vector whose magnitude is the length of that line, which is Sqrt(x*x + y*y), and a direction ?, as measured from positive X axis clockwise. If you’ve read that chapter from Charles Petzold’s book, this much should be clear. Now Sine and Cosine of the angle ? are special. Cosine(?) divides x by the vectors length (adjacent by hypotenuse), thus giving us a unit vector along the X direction. And Sine(?) divides y by the vectors length (opposite by hypotenuse), thus giving us a unit vector along the Y direction. Therefore the vector represented by the pair (cos(?), sin(?)), is the unit vector (or normalization) of the vector (x, y). This unit vector has a length of 1 (remember sin2(?) + cos2(?) = 1 ?), and a direction which is the same as vector (x, y). Now if I multiply this unit vector by some amount, then I will always get a point which is a certain distance away from the origin, but, more importantly, the point will always be on that line. For example, if I multiply the unit vector with the length of the line, I get the point (x, y). Thus, all we have to do to move the marble towards our destination point, is to multiply the unit vector by a certain amount each time and draw the marble, and the marble will magically move towards the click point. Now time for some code. The application, uses a timer based frame draw method to draw the marble on the screen. The timer is disabled initially and whenever the user clicks on the screen, the timer is enabled. The callback function for the timer follows the standard Update and Draw cycle. private double totLenToTravelSqrd = 0; private double startPosX = 0, startPosY = 0; private double destX = 0, destY = 0; private void Form1_MouseUp(object sender, MouseEventArgs e) {     destX = e.X;     destY = e.Y;     double x = marble1.x - destX;     double y = marble1.y - destY;     //calculate the total length to be travelled     totLenToTravelSqrd = x * x + y * y;     //store the start position of the marble     startPosX = marble1.x;     startPosY = marble1.y;     timer1.Enabled = true; } private void timer1_Tick(object sender, EventArgs e) {     UpdatePosition();     DrawMarble(); } Form1_MouseUp() method is called when ever the user touches and releases the screen. In this function we save the click point in destX and destY, this is the destination point for the marble and we also enable the timer. We store a few more values which we will use in the UpdatePosition() method to detect when the marble has reached the destination and stop the timer. So we store the start position of the marble and the square of the total length to be travelled. I’ll leave out the term ‘sqrd’ when speaking of lengths from now on. The time out interval of the timer is set to 40ms, thus giving us a frame rate of about ~25fps. In the timer callback, we update the marble position and draw the marble. We know what DrawMarble() does, so here, we’ll only look at how UpdatePosition() is implemented; private void UpdatePosition() {     //the vector (x, y)     double x = destX - marble1.x;     double y = destY - marble1.y;     double incrX=0, incrY=0;     double distanceSqrd=0;     double speed = 6;     //distance between destination and current position, before updating marble position     distanceSqrd = x * x + y * y;     double angle = Math.Atan2(y, x);     //Cos and Sin give us the unit vector, 6 is the value we use to magnify the unit vector along the same direction     incrX = speed * Math.Cos(angle);     incrY = speed * Math.Sin(angle);     marble1.x += incrX;     marble1.y += incrY;     //check for bounds     if ((int)marble1.x < MinX + marbleWidth / 2)     {         marble1.x = MinX + marbleWidth / 2;     }     else if ((int)marble1.x > (MaxX - marbleWidth / 2))     {         marble1.x = MaxX - marbleWidth / 2;     }     if ((int)marble1.y < MinY + marbleHeight / 2)     {         marble1.y = MinY + marbleHeight / 2;     }     else if ((int)marble1.y > (MaxY - marbleHeight / 2))     {         marble1.y = MaxY - marbleHeight / 2;     }     //distance between destination and current point, after updating marble position     x = destX - marble1.x;     y = destY - marble1.y;     double newDistanceSqrd = x * x + y * y;     //length from start point to current marble position     x = startPosX - (marble1.x);     y = startPosY - (marble1.y);     double lenTraveledSqrd = x * x + y * y;     //check for end conditions     if ((int)lenTraveledSqrd >= (int)totLenToTravelSqrd)     {         System.Console.WriteLine("Stopping because destination reached");         timer1.Enabled = false;     }     else if (Math.Abs((int)distanceSqrd - (int)newDistanceSqrd) < 4)     {         System.Console.WriteLine("Stopping because no change in Old and New position");         timer1.Enabled = false;     } } Ok, so in this function, first we subtract the current marble position from the destination point to give us a vector. The first three lines of the function construct this vector (x, y). The vector (x, y) has the same length as the line from (marble1.x, marble1.y) to (destX, destY) and is in the direction pointing from (marble1.x, marble1.y) to (destX, destY). Note that marble1.x and marble1.y denote the center point of the marble. Then we use Atan2() to get the angle which this vector makes with the positive X axis and use Cosine() and Sine() of that angle to get the unit vector along that same direction. We multiply this unit vector with 6, to get the values which the position of the marble should be incremented by. This variable, speed, can be experimented with and determines how fast the marble moves towards the destination. After this, we check for bounds to make sure that the marble stays within the screen limits and finally we check for the end condition and stop the timer. The end condition has two parts to it. The first case is the normal case, where the user clicks well inside the screen. Here, we stop when the total length travelled by the marble is greater than or equal to the total length to be travelled. Simple enough. The second case is when the user clicks on the very corners of the screen. Like I said before, the values marble1.x and marble1.y denote the center point of the marble. When the user clicks on the corner, the marble moves towards the point, and after some time tries to go outside of the screen, this is when the bounds checking comes into play and corrects the marble position so that the marble stays inside the screen. In this case the marble will never travel a distance of totLenToTravelSqrd, because of the correction is its position. So here we detect the end condition when there is not much change in marbles position. I use the value 4 in the second condition above. After experimenting with a few values, 4 seemed to work okay. There is a small thing missing in the code above. In the normal case, case 1, when the update method runs for the last time, marble position over shoots the destination point. This happens because the position is incremented in steps (which are not small enough), so in this case too, we should have corrected the marble position, so that the center point of the marble sits exactly on top of the destination point. I’ll add this later and update the post. This has been a pretty long post already, so I’ll leave you with a video of how this program looks while running. Notice in the video that the marble moves like a bot, without any grace what so ever. And that is because the speed of the marble is fixed at 6. In the next post we will see how to make the marble move a little more elegantly. And also, if Atan2(), Sine() and Cosine() are a little too much to digest, we’ll see how to achieve the same effect without using them, in the next to next post maybe. Ciao!

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  • Clean Code Development & Flexible work environment - MSCC 26.10.2013

    Finally, some spare time to summarize my impressions and experiences of the recent meetup of Mauritius Software Craftsmanship Community. I already posted my comment on the event and on our social media networks: Professional - It's getting better with our meetups and I really appreciated that 'seniors' and 'juniors' were present today. Despite running a little bit out of time it was really great to see more students coming to the gathering. This time we changed location for our Saturday meetup and it worked out very well. A big thank you to Ebene Accelerator, namely Mrs Poonum, for the ability to use their meeting rooms for our community get-together. Already some weeks ago I had a very pleasant conversation with her about the MSCC aims, 'mission' and how we organise things. Additionally, I think that an environment like the Ebene Accelerator is a good choice as it acts as an incubator for young developers and start-ups. Reactions from other craftsmen Before I put my thoughts about our recent meeting down, I'd like to mention and cross-link to some of the other craftsmen that were present: "MSCC meet up is a massive knowledge gaining strategies for students, future entrepreneurs, or for geeks all around. Knowledge sharing becomes a fun. For those who have not been able to made it do subscribe on our MSCC meet up group at meetup.com." -- Nitin on Learning is fun with #MSCC #Ebene Accelerator "We then talked about the IT industry in Mauritius, salary issues in various field like system administration, software development etc. We analysed the reasons why people tend to hop from one company to another. That was a fun debate." -- Ish on MSCC meetup - Gang of Geeks "Flexible Learning Environment was quite interesting since these lines struck cords : "You're not a secretary....9 to 5 shouldn't suit you"....This allowed reflection...deep reflection....especially regarding the local mindset...which should be changed in a way which would promote creativity rather than choking it till death..." -- Yannick on 2nd MSCC Monthly Meet-up And others on Facebook... ;-) Visual impressions are available on our Meetup event page. More first time attendees We great pleasure I noticed that we have once again more first time visitors. A quick overlook showed that we had a majority of UoM students in first, second or last year. Some of them are already participating in the UoM Computer Club or are nominated as members of the Microsoft Student Partner (MSP) programme. Personally, I really appreciate the fact that the MSCC is able to gather such a broad audience. And as I wrote initially, the MSCC is technology-agnostic; we want IT people from any segment of this business. Of course, students which are about to delve into the 'real world' of working are highly welcome, and I hope that they might get one or other glimpse of experience or advice from employees. Sticking to the schedule? No, not really... And honestly, it was a good choice to go a little bit of the beaten tracks. I mean, yes we have a 'rough' agenda of topics that we would like to talk about or having a presentation about. But we keep it 'agile'. Due to the high number of new faces, we initiated another quick round of introductions and I gave a really brief overview of the MSCC. Next, we started to reflect on the Clean Code Developer (CCD) - Red Grade which we introduced on the last meetup. Nirvan was the lucky one and he did a good job on summarizing the various abbreviations of the first level of being a CCD. Actually, more interesting, we exchanged experience about the principles and practices of Red Grade, and it was very informative to get to know that Yann actually 'interviewed' a couple of friends, other students, local guys working in IT companies as well as some IT friends from India in order to counter-check on what he learned first-hand about Clean Code. Currently, he is reading the book of Robert C. Martin on that topic and I'm looking forward to his review soon. More output generates more input What seems to be like a personal mantra is working out pretty well for me since the beginning of this year. Being more active on social media networks, writing more article on my blog, starting the Mauritius Software Craftsmanship Community, and contributing more to other online communities has helped me to receive more project requests, job offers and possibilities to expand my business at IOS Indian Ocean Software Ltd. Actually, it is not a coincidence that one of the questions new craftsmen should answer during registration asks about having a personal blog. Whether you are just curious about IT, right in the middle of your Computer Studies, or already working in software development or system administration since a while you should consider to advertise and market yourself online. Easiest way to resolve this are to have online profiles on professional social media networks like LinkedIn, Xing, Twitter, and Google+ (no Facebook should be considered for private only), and considering to have a personal blog. Why? -- Be yourself, be proud of your work, and let other people know that you're passionate about your profession. Trust me, this is going to open up opportunities you might not have dreamt about... Exchanging ideas about having a professional online presence - MSCC meetup on the 26th October 2013 Furthermore, consider to put your Curriculum Vitae online, too. There are quite a number of service providers like 1ClickCV, Stack Overflow Careers 2.0, etc. which give you the ability to have an up to date CV online. At least put it on your site, next to your personal blog. Similar to what you would be able to see on my site here. Cyber Island Mauritius - are we there? A couple of weeks ago I got a 'cold' message on LinkedIn from someone living in the U.S. asking about the circumstances and conditions of the IT world of Mauritius. He has a great business idea, venture capital and is currently looking for a team of software developers (mainly mobile - iOS) for a new startup here in Mauritius. Since then we exchanged quite some details through private messages and Skype conversations, and I suggested that it might be a good chance to join our meetup through a conference call and see for yourself about potential candidates. During approximately 30 to 40 minutes the brief idea of the new startup was presented - very promising state-of-the-art technology aspects and integration of various public APIs -, and we had a good Q&A session about it. Also thanks to the excellent bandwidth provided by the Ebene Accelerator the video conference between three parties went absolutely well. Clean Code Developer - Orange Grade Hahaha - nice one... Being at the Orange Tower at Ebene and then talking about an Orange Grade as CCD. Well, once again I provided an overview of the principles and practices in that rank of Clean Code, and similar to our last meetup we discussed on the various aspect of each principle, whether someone already got in touch with it during studies or work, and how it could affect their future view on their source code. Following are the principles and practices of Clean Code Developer - Orange Grade: CCD Orange Grade - Principles Single Level of Abstraction (SLA) Single Responsibility Principle (SRP) Separation of Concerns (SoC) Source Code conventions CCD Orange Grade - Practices Issue Tracking Automated Integration Tests Reading, Reading, Reading Reviews Especially the part on reading technical books got some extra attention. We quickly gathered our views on that and came up with a result that ranges between Zero (0) and up to Fifteen (15) book titles per year. Personally, I'm keeping my progress between Six (6) and Eight (8) titles per year, but at least One (1) per quarter of a year. Which is also connected to the fact that I'm participating in the O'Reilly Reader Review Program and have a another benefit to get access to free books only by writing and publishing a review afterwards. We also had a good exchange on the extended topic of 'Reviews' - which to my opinion is abnormal difficult here in Mauritius for various reasons. As far as I can tell from my experience working with Mauritian software developers, either as colleagues, employees or during consulting services there are unfortunately two dominant pattern on that topic: Keeping quiet Running away Honestly, I have no evidence about why these are the two 'solutions' on reviews but that's the situation that I had to face over the last couple of years. Sitting together and talking about problematic issues, tackling down root causes of de-motivational activities and working on general improvements doesn't seem to have a ground within the IT world of Mauritius. Are you a typist or a creative software craftsman? - MSCC meetup on the 26th October 2013 One very good example that we talked about was the fact of 'job hoppers' as you can easily observe it on someone's CV - those people change job every single year; for no obvious reason! Frankly speaking, I wouldn't even consider an IT person like to for an interview. As a company you're investing money and effort into the abilities of your employees. Hiring someone that won't stay for a longer period is out of question. And sorry to say, these kind of IT guys smell fishy about their capabilities and more likely to cause problems than actually produce productive results. One of the reasons why there is a probation period on an employment contract is to give you the liberty to leave as early as possible in case that you don't like your new position. Don't fool yourself or waste other people's time and money by hanging around a full year only to snatch off the bonus payment... Future outlook: Developer's Conference Even though it is not official yet I already mentioned it several times during our weekly Code & Coffee sessions. The MSCC is looking forward to be able to organise or to contribute to an upcoming IT event. Currently, the rough schedule is set for April 2014 but this mainly depends on availability of location(s), a decent time frame for preparations, and the underlying procedures with public bodies to have it approved and so on. As soon as the information about date and location has been fixed there will be a 'Call for Papers' period in order to attract local IT enthusiasts to apply for a session slot and talk about their field of work and their passion in IT. More to come for sure... My resume of the day It was a great gathering and I am very pleased about the fact that we had another 15 craftsmen (plus 2 businessmen on conference call plus 2 young apprentices) in the same room, talking about IT related topics and sharing their experience as employees and students. Personally, I really appreciated the feedback from the students about their current view on their future career, and I really hope that some of them are going to pursue their dreams. Start promoting yourself and it will happen... Looking forward to your blogs! And last but not least our numbers on Meetup and Facebook have been increased as a direct consequence of this meetup. Please, spread the word about the MSCC and get your friends and colleagues to join our official site. The higher the number of craftsmen we have the better chances we have t achieve something great! Thanks!

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  • Session Evaluations

    - by BuckWoody
    I do a lot of public speaking. I write, teach, present and communicate at many levels. I love to do those things. And I love to get better at them. And one of the ways you get better at something is to get feedback on how you did. That being said, I have to confess that I really despise the “evaluations” I get at most venues. From college to technical events to other locations, at Microsoft and points in between, I find these things to be just shy of damaging, and most certainly useless. And it’s not always your fault. Ouch. That seems harsh. But let me ask you one question – and be as honest as you can with the answer – think about it first: “What is the point of a session evaluation?” I’m not saying there isn’t one. In fact, I think there’s a really important reason for them. In my mind, it’s really this: To make the speaker / next session better. Now, if you look at that, you can see right away that most session evals don’t accomplish this goal – not even a little. No, the way that they are worded and the way you (and I) fill them out, it’s more like the implied goal is this: Tell us how you liked this speaker / session. The current ones are for you, not for the speaker or the next person. It’s a popularity contest. Don’t get me wrong. I want to you have a good time. I want you to learn. I want (desperately, oh, please oh please) for you to like me. But in fact, that’s probably not why you went to the session / took the class / read that post. No, you want to learn, and to learn for a particular reason. Remember, I’m talking about college classes, sessions and other class environments here, not a general public event. Most – OK, all – session evaluations make you answer the second goal, not the first. Let’s see how: First, they don’t ask you why you’re there. They don’t ask you if you’re even qualified to evaluate the session or speaker. They don’t ask you how to make it better or keep it great. They use odd numeric scales that are meaningless. For instance, can someone really tell me the difference between a 100-level session and a 200-level one? Between a 400-level and a 500? Is it “internals” (whatever that means) or detail, or length or code, or what? I once heard a great description: A 100-level session makes me say, “wow - I’m smart.” A 500-level session makes me say “wow – that presenter is smart.” And just what is the difference between a 6 and a 7 answer on this question: How well did the speaker know the material? 1  2  3  4  5  6  7  8  9  10 Oh. My. Gosh. How does that make the next session better, or the speaker? And what criteria did you use to answer? And is a “10” better than a “1” (not always clear, and various cultures answer this differently). When it’s all said and done, a speaker basically finds out one thing from the current session evals: “They liked me. They really really liked me.” Or, “Wow. I think I may need to schedule some counseling for the depression I’m about to go into.” You may not think that’s what the speaker hears, but trust me, they do. Those are the only two reactions to the current feedback sheets they get. Either they keep doing what they are doing, or they get their feelings hurt. They just can’t use the information provided to do better. Sorry, but there it is. Keep in mind I do want your feedback. I want to get better. I want you to get your money and time’s worth, probably as much as any speaker alive. But I want those evaluations to be accurate, specific and actionable. I want to know if you had a good time, sure, but I also want to know if I did the right things, and if not, if I can do something different or better. And so, for your consideration, here is the evaluation form I would LOVE for you to use. Feel free to copy it and mail it to me any time. I’m going to put some questions here, and then I’ll even include why they are there. Notice that the form asks you a subjective question right away, and then makes you explain why. That’s work on your part. Notice also that it separates the room and the coffee and the lights and the LiveMeeting from the presenter. So many presenters are faced with circumstances beyond their control, and yet are rated high or low personally on those things. This form helps tease those apart. It’s not numeric. Numbers are easier for the scoring committees but are useless for you and me. So I don’t have any numbers. We’re actually going to have to read these things, not put them in a machine. Hey, if you put in the work to write stuff down, the least we could do is take the time to read it. It’s not anonymous. If you’ve got something to say, say it, and own up to it. People are not “more honest” when they are anonymous, they are less honest. So put your name on it. In fact – this is radical – I posit that these evaluations should be publicly available. Forever. Just like replies to a blog post. Hey, if I’m an organizer, I would LOVE to be able to have access to specific, actionable information on the attendees and the speakers. So if you want mine to be public, go for it. I’ll take the good and the bad. Enjoy. ------------------------------------------------------------------------------------------------------------------------------------------- Session Evaluation – Date, Time, Location, Topic Thanks for giving us your time today. We know that’s valuable, and we hope you learned something you can use from the session. If you can answer these questions as completely as you can, it will help the next person who attends a session here. Your Name: What you do for a living: (We Need your background to evaluate your evaluation) How long you have been doing that: (Again, we need your background to evaluate your evaluation) Paste Session Description Here: (This is what I said I would talk about) Did you like the session?                     No        Meh        Yes (General subjective question – overall “feeling”. You’ll tell us why in a minute.)  Tell us about the venue. Temperature, lights, coffee, or the online sound, performance, anything other than the speaker and the material. (Helps the logistics to be better or as good for the next person) 1. What did you expect to learn in this session? (How did you interpret that extract – did you have expectations that I should work towards for the next person?) 2. Did you learn what you expected to learn? Why? Be very specific. (This is the most important question there is. It tells us how to make the session better for someone like you.) 3. If you were giving this presentation, would you have done anything differently? What? (Helps us to gauge you, the listener, and might give us a great idea on how to do something better. Thanks!) 4. What will you do with the information you got? (Every presenter wants you to learn, and learn something useful. This will help us do that as well or better)  

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  • Stumbling Through: Visual Studio 2010 (Part III)

    The last post ended with us just getting started on stumbling into text template file customization, a task that required a Visual Studio extension (Tangible T4 Editor) to even have a chance at completing.  Despite the benefits of the Tangible T4 Editor, I still had a hard time putting together a solid text template that would be easy to explain.  This is mostly due to the way the files allow you to mix code (encapsulated in <# #>) with straight-up text to generate.  It is effective to be sure, but not very readable.  Nevertheless, I will try and explain what was accomplished in my custom tt file, though the details of which are not really the point of this article (my way of saying dont criticize my crappy code, and certainly dont use it in any somewhat real application.  You may become dumber just by looking at this code.  You have been warned really the footnote I should put at the end of all of my blog posts). To begin with, there were two basic requirements that I needed the code generator to satisfy:  Reading one to many entity framework files, and using the entities that were found to write one to many class files.  Thankfully, using the Entity Object Generator as a starting point gave us an example on how to do exactly that by using the MetadataLoader and EntityFrameworkTemplateFileManager you include references to these items and use them like so: // Instantiate an entity framework file reader and file writer MetadataLoader loader = new MetadataLoader(this); EntityFrameworkTemplateFileManager fileManager = EntityFrameworkTemplateFileManager.Create(this); // Load the entity model metadata workspace MetadataWorkspace metadataWorkspace = null; bool allMetadataLoaded =loader.TryLoadAllMetadata("MFL.tt", out metadataWorkspace); EdmItemCollection ItemCollection = (EdmItemCollection)metadataWorkspace.GetItemCollection(DataSpace.CSpace); // Create an IO class to contain the 'get' methods for all entities in the model fileManager.StartNewFile("MFL.IO.gen.cs"); Next, we want to be able to loop through all of the entities found in the model, and then each property for each entity so we can generate classes and methods for each.  The code for that is blissfully simple: // Iterate through each entity in the model foreach (EntityType entity in ItemCollection.GetItems<EntityType>().OrderBy(e => e.Name)) {     // Iterate through each primitive property of the entity     foreach (EdmProperty edmProperty in entity.Properties.Where(p => p.TypeUsage.EdmType is PrimitiveType && p.DeclaringType == entity))     {         // TODO:  Create properties     }     // Iterate through each relationship of the entity     foreach (NavigationProperty navProperty in entity.NavigationProperties.Where(np => np.DeclaringType == entity))     {         // TODO:  Create associations     } } There really isnt anything more advanced than that going on in the text template the only thing I had to blunder through was realizing that if you want the generator to interpret a line of code (such as our iterations above), you need to enclose the code in <# and #> while if you want the generator to interpret the VALUE of code, such as putting the entity name into the class name, you need to enclose the code in <#= and #> like so: public partial class <#=entity.Name#> To make a long story short, I did a lot of repetition of the above to come up with a text template that generates a class for each entity based on its properties, and a set of IO methods for each entity based on its relationships.  The two work together to provide lazy-loading for hierarchical data (such getting Team.Players) so it should be pretty intuitive to use on a front-end.  This text template is available here you can tweak the inputFiles array to load one or many different edmx models and generate the basic xml IO and class files, though it will probably only work correctly in the simplest of cases, like our MFL model described in the previous post.  Additionally, there is no validation, logging or error handling which is something I want to handle later by stumbling through the enterprise library 5.0. The code that gets generated isnt anything special, though using the LINQ to XML feature was something very new and exciting for me I had only worked with XML in the past using the DOM or XML Reader objects along with XPath, and the LINQ to XML model is just so much more elegant and supposedly efficient (something to test later).  For example, the following code was generated to create a Player object for each Player node in the XML:         return from element in GetXmlData(_PlayerDataFile).Descendants("Player")             select new Player             {                 Id = int.Parse(element.Attribute("Id").Value)                 ,ParentName = element.Parent.Name.LocalName                 ,ParentId = long.Parse(element.Parent.Attribute("Id").Value)                 ,Name = element.Attribute("Name").Value                 ,PositionId = int.Parse(element.Attribute("PositionId").Value)             }; It is all done in one line of code, no looping needed.  Even though GetXmlData loads the entire xml file just like the old XML DOM approach would have, it is supposed to be much less resource intensive.  I will definitely put that to the test after we develop a user interface for getting at this data.  Speaking of the data where IS the data?  Weve put together a pretty model and a bunch of code around it, but we dont have any data to speak of.  We can certainly drop to our favorite XML editor and crank out some data, but if it doesnt totally match our model, it will not load correctly.  To help with this, Ive built in a method to generate xml at any given layer in the hierarchy.  So for us to get the closest possible thing to real data, wed need to invoke MFL.IO.GenerateTeamXML and save the results to file.  Doing so should get us something that looks like this: <Team Id="0" Name="0">   <Player Id="0" Name="0" PositionId="0">     <Statistic Id="0" PassYards="0" RushYards="0" Year="0" />   </Player> </Team> Sadly, it is missing the Positions node (havent thought of a way to generate lookup xml yet) and the data itself isnt quite realistic (well, as realistic as MFL data can be anyway).  Lets manually remedy that for now to give us a decent starter set of data.  Note that this is TWO xml files Lookups.xml and Teams.xml: <Lookups Id=0>   <Position Id="0" Name="Quarterback"/>   <Position Id="1" Name="Runningback"/> </Lookups> <Teams Id=0>   <Team Id="0" Name="Chicago">     <Player Id="0" Name="QB Bears" PositionId="0">       <Statistic Id="0" PassYards="4000" RushYards="120" Year="2008" />       <Statistic Id="1" PassYards="4200" RushYards="180" Year="2009" />     </Player>     <Player Id="1" Name="RB Bears" PositionId="1">       <Statistic Id="2" PassYards="0" RushYards="800" Year="2007" />       <Statistic Id="3" PassYards="0" RushYards="1200" Year="2008" />       <Statistic Id="4" PassYards="3" RushYards="1450" Year="2009" />     </Player>   </Team> </Teams> Ok, so we have some data, we have a way to read/write that data and we have a friendly way of representing that data.  Now, what remains is the part that I have been looking forward to the most: present the data to the user and give them the ability to add/update/delete, and doing so in a way that is very intuitive (easy) from a development standpoint.Did you know that DotNetSlackers also publishes .net articles written by top known .net Authors? We already have over 80 articles in several categories including Silverlight. Take a look: here.

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  • Stumbling Through: Visual Studio 2010 (Part III)

    The last post ended with us just getting started on stumbling into text template file customization, a task that required a Visual Studio extension (Tangible T4 Editor) to even have a chance at completing.  Despite the benefits of the Tangible T4 Editor, I still had a hard time putting together a solid text template that would be easy to explain.  This is mostly due to the way the files allow you to mix code (encapsulated in <# #>) with straight-up text to generate.  It is effective to be sure, but not very readable.  Nevertheless, I will try and explain what was accomplished in my custom tt file, though the details of which are not really the point of this article (my way of saying dont criticize my crappy code, and certainly dont use it in any somewhat real application.  You may become dumber just by looking at this code.  You have been warned really the footnote I should put at the end of all of my blog posts). To begin with, there were two basic requirements that I needed the code generator to satisfy:  Reading one to many entity framework files, and using the entities that were found to write one to many class files.  Thankfully, using the Entity Object Generator as a starting point gave us an example on how to do exactly that by using the MetadataLoader and EntityFrameworkTemplateFileManager you include references to these items and use them like so: // Instantiate an entity framework file reader and file writer MetadataLoader loader = new MetadataLoader(this); EntityFrameworkTemplateFileManager fileManager = EntityFrameworkTemplateFileManager.Create(this); // Load the entity model metadata workspace MetadataWorkspace metadataWorkspace = null; bool allMetadataLoaded =loader.TryLoadAllMetadata("MFL.tt", out metadataWorkspace); EdmItemCollection ItemCollection = (EdmItemCollection)metadataWorkspace.GetItemCollection(DataSpace.CSpace); // Create an IO class to contain the 'get' methods for all entities in the model fileManager.StartNewFile("MFL.IO.gen.cs"); Next, we want to be able to loop through all of the entities found in the model, and then each property for each entity so we can generate classes and methods for each.  The code for that is blissfully simple: // Iterate through each entity in the model foreach (EntityType entity in ItemCollection.GetItems<EntityType>().OrderBy(e => e.Name)) {     // Iterate through each primitive property of the entity     foreach (EdmProperty edmProperty in entity.Properties.Where(p => p.TypeUsage.EdmType is PrimitiveType && p.DeclaringType == entity))     {         // TODO:  Create properties     }     // Iterate through each relationship of the entity     foreach (NavigationProperty navProperty in entity.NavigationProperties.Where(np => np.DeclaringType == entity))     {         // TODO:  Create associations     } } There really isnt anything more advanced than that going on in the text template the only thing I had to blunder through was realizing that if you want the generator to interpret a line of code (such as our iterations above), you need to enclose the code in <# and #> while if you want the generator to interpret the VALUE of code, such as putting the entity name into the class name, you need to enclose the code in <#= and #> like so: public partial class <#=entity.Name#> To make a long story short, I did a lot of repetition of the above to come up with a text template that generates a class for each entity based on its properties, and a set of IO methods for each entity based on its relationships.  The two work together to provide lazy-loading for hierarchical data (such getting Team.Players) so it should be pretty intuitive to use on a front-end.  This text template is available here you can tweak the inputFiles array to load one or many different edmx models and generate the basic xml IO and class files, though it will probably only work correctly in the simplest of cases, like our MFL model described in the previous post.  Additionally, there is no validation, logging or error handling which is something I want to handle later by stumbling through the enterprise library 5.0. The code that gets generated isnt anything special, though using the LINQ to XML feature was something very new and exciting for me I had only worked with XML in the past using the DOM or XML Reader objects along with XPath, and the LINQ to XML model is just so much more elegant and supposedly efficient (something to test later).  For example, the following code was generated to create a Player object for each Player node in the XML:         return from element in GetXmlData(_PlayerDataFile).Descendants("Player")             select new Player             {                 Id = int.Parse(element.Attribute("Id").Value)                 ,ParentName = element.Parent.Name.LocalName                 ,ParentId = long.Parse(element.Parent.Attribute("Id").Value)                 ,Name = element.Attribute("Name").Value                 ,PositionId = int.Parse(element.Attribute("PositionId").Value)             }; It is all done in one line of code, no looping needed.  Even though GetXmlData loads the entire xml file just like the old XML DOM approach would have, it is supposed to be much less resource intensive.  I will definitely put that to the test after we develop a user interface for getting at this data.  Speaking of the data where IS the data?  Weve put together a pretty model and a bunch of code around it, but we dont have any data to speak of.  We can certainly drop to our favorite XML editor and crank out some data, but if it doesnt totally match our model, it will not load correctly.  To help with this, Ive built in a method to generate xml at any given layer in the hierarchy.  So for us to get the closest possible thing to real data, wed need to invoke MFL.IO.GenerateTeamXML and save the results to file.  Doing so should get us something that looks like this: <Team Id="0" Name="0">   <Player Id="0" Name="0" PositionId="0">     <Statistic Id="0" PassYards="0" RushYards="0" Year="0" />   </Player> </Team> Sadly, it is missing the Positions node (havent thought of a way to generate lookup xml yet) and the data itself isnt quite realistic (well, as realistic as MFL data can be anyway).  Lets manually remedy that for now to give us a decent starter set of data.  Note that this is TWO xml files Lookups.xml and Teams.xml: <Lookups Id=0>   <Position Id="0" Name="Quarterback"/>   <Position Id="1" Name="Runningback"/> </Lookups> <Teams Id=0>   <Team Id="0" Name="Chicago">     <Player Id="0" Name="QB Bears" PositionId="0">       <Statistic Id="0" PassYards="4000" RushYards="120" Year="2008" />       <Statistic Id="1" PassYards="4200" RushYards="180" Year="2009" />     </Player>     <Player Id="1" Name="RB Bears" PositionId="1">       <Statistic Id="2" PassYards="0" RushYards="800" Year="2007" />       <Statistic Id="3" PassYards="0" RushYards="1200" Year="2008" />       <Statistic Id="4" PassYards="3" RushYards="1450" Year="2009" />     </Player>   </Team> </Teams> Ok, so we have some data, we have a way to read/write that data and we have a friendly way of representing that data.  Now, what remains is the part that I have been looking forward to the most: present the data to the user and give them the ability to add/update/delete, and doing so in a way that is very intuitive (easy) from a development standpoint.Did you know that DotNetSlackers also publishes .net articles written by top known .net Authors? We already have over 80 articles in several categories including Silverlight. Take a look: here.

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  • Oracle BI Server Modeling, Part 1- Designing a Query Factory

    - by bob.ertl(at)oracle.com
      Welcome to Oracle BI Development's BI Foundation blog, focused on helping you get the most value from your Oracle Business Intelligence Enterprise Edition (BI EE) platform deployments.  In my first series of posts, I plan to show developers the concepts and best practices for modeling in the Common Enterprise Information Model (CEIM), the semantic layer of Oracle BI EE.  In this segment, I will lay the groundwork for the modeling concepts.  First, I will cover the big picture of how the BI Server fits into the system, and how the CEIM controls the query processing. Oracle BI EE Query Cycle The purpose of the Oracle BI Server is to bridge the gap between the presentation services and the data sources.  There are typically a variety of data sources in a variety of technologies: relational, normalized transaction systems; relational star-schema data warehouses and marts; multidimensional analytic cubes and financial applications; flat files, Excel files, XML files, and so on. Business datasets can reside in a single type of source, or, most of the time, are spread across various types of sources. Presentation services users are generally business people who need to be able to query that set of sources without any knowledge of technologies, schemas, or how sources are organized in their company. They think of business analysis in terms of measures with specific calculations, hierarchical dimensions for breaking those measures down, and detailed reports of the business transactions themselves.  Most of them create queries without knowing it, by picking a dashboard page and some filters.  Others create their own analysis by selecting metrics and dimensional attributes, and possibly creating additional calculations. The BI Server bridges that gap from simple business terms to technical physical queries by exposing just the business focused measures and dimensional attributes that business people can use in their analyses and dashboards.   After they make their selections and start the analysis, the BI Server plans the best way to query the data sources, writes the optimized sequence of physical queries to those sources, post-processes the results, and presents them to the client as a single result set suitable for tables, pivots and charts. The CEIM is a model that controls the processing of the BI Server.  It provides the subject areas that presentation services exposes for business users to select simplified metrics and dimensional attributes for their analysis.  It models the mappings to the physical data access, the calculations and logical transformations, and the data access security rules.  The CEIM consists of metadata stored in the repository, authored by developers using the Administration Tool client.     Presentation services and other query clients create their queries in BI EE's SQL-92 language, called Logical SQL or LSQL.  The API simply uses ODBC or JDBC to pass the query to the BI Server.  Presentation services writes the LSQL query in terms of the simplified objects presented to the users.  The BI Server creates a query plan, and rewrites the LSQL into fully-detailed SQL or other languages suitable for querying the physical sources.  For example, the LSQL on the left below was rewritten into the physical SQL for an Oracle 11g database on the right. Logical SQL   Physical SQL SELECT "D0 Time"."T02 Per Name Month" saw_0, "D4 Product"."P01  Product" saw_1, "F2 Units"."2-01  Billed Qty  (Sum All)" saw_2 FROM "Sample Sales" ORDER BY saw_0, saw_1       WITH SAWITH0 AS ( select T986.Per_Name_Month as c1, T879.Prod_Dsc as c2,      sum(T835.Units) as c3, T879.Prod_Key as c4 from      Product T879 /* A05 Product */ ,      Time_Mth T986 /* A08 Time Mth */ ,      FactsRev T835 /* A11 Revenue (Billed Time Join) */ where ( T835.Prod_Key = T879.Prod_Key and T835.Bill_Mth = T986.Row_Wid) group by T879.Prod_Dsc, T879.Prod_Key, T986.Per_Name_Month ) select SAWITH0.c1 as c1, SAWITH0.c2 as c2, SAWITH0.c3 as c3 from SAWITH0 order by c1, c2   Probably everybody reading this blog can write SQL or MDX.  However, the trick in designing the CEIM is that you are modeling a query-generation factory.  Rather than hand-crafting individual queries, you model behavior and relationships, thus configuring the BI Server machinery to manufacture millions of different queries in response to random user requests.  This mass production requires a different mindset and approach than when you are designing individual SQL statements in tools such as Oracle SQL Developer, Oracle Hyperion Interactive Reporting (formerly Brio), or Oracle BI Publisher.   The Structure of the Common Enterprise Information Model (CEIM) The CEIM has a unique structure specifically for modeling the relationships and behaviors that fill the gap from logical user requests to physical data source queries and back to the result.  The model divides the functionality into three specialized layers, called Presentation, Business Model and Mapping, and Physical, as shown below. Presentation services clients can generally only see the presentation layer, and the objects in the presentation layer are normally the only ones used in the LSQL request.  When a request comes into the BI Server from presentation services or another client, the relationships and objects in the model allow the BI Server to select the appropriate data sources, create a query plan, and generate the physical queries.  That's the left to right flow in the diagram below.  When the results come back from the data source queries, the right to left relationships in the model show how to transform the results and perform any final calculations and functions that could not be pushed down to the databases.   Business Model Think of the business model as the heart of the CEIM you are designing.  This is where you define the analytic behavior seen by the users, and the superset library of metric and dimension objects available to the user community as a whole.  It also provides the baseline business-friendly names and user-readable dictionary.  For these reasons, it is often called the "logical" model--it is a virtual database schema that persists no data, but can be queried as if it is a database. The business model always has a dimensional shape (more on this in future posts), and its simple shape and terminology hides the complexity of the source data models. Besides hiding complexity and normalizing terminology, this layer adds most of the analytic value, as well.  This is where you define the rich, dimensional behavior of the metrics and complex business calculations, as well as the conformed dimensions and hierarchies.  It contributes to the ease of use for business users, since the dimensional metric definitions apply in any context of filters and drill-downs, and the conformed dimensions enable dashboard-wide filters and guided analysis links that bring context along from one page to the next.  The conformed dimensions also provide a key to hiding the complexity of many sources, including federation of different databases, behind the simple business model. Note that the expression language in this layer is LSQL, so that any expression can be rewritten into any data source's query language at run time.  This is important for federation, where a given logical object can map to several different physical objects in different databases.  It is also important to portability of the CEIM to different database brands, which is a key requirement for Oracle's BI Applications products. Your requirements process with your user community will mostly affect the business model.  This is where you will define most of the things they specifically ask for, such as metric definitions.  For this reason, many of the best-practice methodologies of our consulting partners start with the high-level definition of this layer. Physical Model The physical model connects the business model that meets your users' requirements to the reality of the data sources you have available. In the query factory analogy, think of the physical layer as the bill of materials for generating physical queries.  Every schema, table, column, join, cube, hierarchy, etc., that will appear in any physical query manufactured at run time must be modeled here at design time. Each physical data source will have its own physical model, or "database" object in the CEIM.  The shape of each physical model matches the shape of its physical source.  In other words, if the source is normalized relational, the physical model will mimic that normalized shape.  If it is a hypercube, the physical model will have a hypercube shape.  If it is a flat file, it will have a denormalized tabular shape. To aid in query optimization, the physical layer also tracks the specifics of the database brand and release.  This allows the BI Server to make the most of each physical source's distinct capabilities, writing queries in its syntax, and using its specific functions. This allows the BI Server to push processing work as deep as possible into the physical source, which minimizes data movement and takes full advantage of the database's own optimizer.  For most data sources, native APIs are used to further optimize performance and functionality. The value of having a distinct separation between the logical (business) and physical models is encapsulation of the physical characteristics.  This encapsulation is another enabler of packaged BI applications and federation.  It is also key to hiding the complex shapes and relationships in the physical sources from the end users.  Consider a routine drill-down in the business model: physically, it can require a drill-through where the first query is MDX to a multidimensional cube, followed by the drill-down query in SQL to a normalized relational database.  The only difference from the user's point of view is that the 2nd query added a more detailed dimension level column - everything else was the same. Mappings Within the Business Model and Mapping Layer, the mappings provide the binding from each logical column and join in the dimensional business model, to each of the objects that can provide its data in the physical layer.  When there is more than one option for a physical source, rules in the mappings are applied to the query context to determine which of the data sources should be hit, and how to combine their results if more than one is used.  These rules specify aggregate navigation, vertical partitioning (fragmentation), and horizontal partitioning, any of which can be federated across multiple, heterogeneous sources.  These mappings are usually the most sophisticated part of the CEIM. Presentation You might think of the presentation layer as a set of very simple relational-like views into the business model.  Over ODBC/JDBC, they present a relational catalog consisting of databases, tables and columns.  For business users, presentation services interprets these as subject areas, folders and columns, respectively.  (Note that in 10g, subject areas were called presentation catalogs in the CEIM.  In this blog, I will stick to 11g terminology.)  Generally speaking, presentation services and other clients can query only these objects (there are exceptions for certain clients such as BI Publisher and Essbase Studio). The purpose of the presentation layer is to specialize the business model for different categories of users.  Based on a user's role, they will be restricted to specific subject areas, tables and columns for security.  The breakdown of the model into multiple subject areas organizes the content for users, and subjects superfluous to a particular business role can be hidden from that set of users.  Customized names and descriptions can be used to override the business model names for a specific audience.  Variables in the object names can be used for localization. For these reasons, you are better off thinking of the tables in the presentation layer as folders than as strict relational tables.  The real semantics of tables and how they function is in the business model, and any grouping of columns can be included in any table in the presentation layer.  In 11g, an LSQL query can also span multiple presentation subject areas, as long as they map to the same business model. Other Model Objects There are some objects that apply to multiple layers.  These include security-related objects, such as application roles, users, data filters, and query limits (governors).  There are also variables you can use in parameters and expressions, and initialization blocks for loading their initial values on a static or user session basis.  Finally, there are Multi-User Development (MUD) projects for developers to check out units of work, and objects for the marketing feature used by our packaged customer relationship management (CRM) software.   The Query Factory At this point, you should have a grasp on the query factory concept.  When developing the CEIM model, you are configuring the BI Server to automatically manufacture millions of queries in response to random user requests. You do this by defining the analytic behavior in the business model, mapping that to the physical data sources, and exposing it through the presentation layer's role-based subject areas. While configuring mass production requires a different mindset than when you hand-craft individual SQL or MDX statements, it builds on the modeling and query concepts you already understand. The following posts in this series will walk through the CEIM modeling concepts and best practices in detail.  We will initially review dimensional concepts so you can understand the business model, and then present a pattern-based approach to learning the mappings from a variety of physical schema shapes and deployments to the dimensional model.  Along the way, we will also present the dimensional calculation template, and learn how to configure the many additivity patterns.

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  • Using Oracle Proxy Authentication with JPA (eclipselink-Style)

    - by olaf.heimburger
    Security is a very intriguing topic. You will find it everywhere and you need to implement it everywhere. Yes, you need. Unfortunately, one can easily forget it while implementing the last mile. The Last Mile In a multi-tier application it is a common practice to use connection pools between the business layer and the database layer. Connection pools are quite useful to speed database connection creation and to split the load. Another very common practice is to use a specific, often called technical, user to connect to the database. This user has authentication and authorization rules that apply to all application users. Imagine you've put every effort to define roles for different types of users that use your application. These roles are necessary to differentiate between normal users, premium users, and administrators (I bet you will find or already have more roles in your application). While these user roles are pretty well used within your application, once the flow of execution enters the database everything is gone. Each and every user just has one role and is the same database user. Issues? What Issues? As long as things go well, this is not a real issue. However, things do not go well all the time. Once your application becomes famous performance decreases in certain situations or, more importantly, current and upcoming regulations and laws require that your application must be able to apply different security measures on a per user role basis at every stage of your application. If you only have a bunch of users with the same name and role you are not able to find the application usage profile that causes the performance issue, or which user has accessed data that he/she is not allowed to. Another thread to your role concept is that databases tend to be used by different applications and tools. These tools can be developer tools like SQL*Plus, SQL Developer, etc. or end user applications like BI Publisher, Oracle Forms and so on. These tools have no idea of your applications role concept and access the database the way they think is appropriate. A big oversight for your perfect role model and a big nightmare for your Chief Security Officer. Speaking of the CSO, brings up another issue: Password management. Once your technical user account is compromised, every user is able to do things that he/she is not expected to do from the design of your application. Counter Measures In the Oracle world a common counter measure is to use Virtual Private Database (VPD). This restricts the values a database user can see to the allowed minimum. However, it doesn't help in regard of a connection pool user, because this one is still not the real user. Oracle Proxy Authentication Another feature of the Oracle database is Proxy Authentication. First introduced with version 9i it is a quite useful feature for nearly every situation. The main idea behind Proxy Authentication is, to create a crippled database user who has only connect rights. Even if this user is compromised the risks are well understood and fairly limited. This user can be used in every situation in which you need to connect to the database, no matter which tool or application (see above) you use.The proxy user is perfect for multi-tier connection pools. CREATE USER app_user IDENTIFIED BY abcd1234; GRANT CREATE SESSION TO app_user; But what if you need to access real data? Well, this is the primary use case, isn't it? Now is the time to bring the application's role concept into play. You define database roles that define the grants for your identified user groups. Once you have these groups you grant access through the proxy user with the application role to the specific user. CREATE ROLE app_role_a; GRANT app_role_a TO scott; ALTER USER scott GRANT CONNECT THROUGH app_user WITH ROLE app_role_a; Now, hr has permission to connect to the database through the proxy user. Through the role you can restrict the hr's rights the are needed for the application only. If hr connects to the database directly all assigned role and permissions apply. Testing the Setup To test the setup you can use SQL*Plus and connect to your database: $ sqlplus app_user[hr]/abcd1234 Java Persistence API The Java Persistence API (JPA) is a fairly easy means to build applications that retrieve data from the database and put it into Java objects. You use plain old Java objects (POJOs) and mixin some Java annotations that define how the attributes of the object are used for storing data from the database into the Java object. Here is a sample for objects from the HR sample schema EMPLOYEES table. When using Java annotations you only specify what can not be deduced from the code. If your Java class name is Employee but the table name is EMPLOYEES, you need to specify the table name, otherwise it will fail. package demo.proxy.ejb; import java.io.Serializable; import java.sql.Timestamp; import java.util.List; import javax.persistence.Column; import javax.persistence.Entity; import javax.persistence.Id; import javax.persistence.JoinColumn; import javax.persistence.ManyToOne; import javax.persistence.NamedQueries; import javax.persistence.NamedQuery; import javax.persistence.OneToMany; import javax.persistence.Table; @Entity @NamedQueries({ @NamedQuery(name = "Employee.findAll", query = "select o from Employee o") }) @Table(name = "EMPLOYEES") public class Employee implements Serializable { @Column(name="COMMISSION_PCT") private Double commissionPct; @Column(name="DEPARTMENT_ID") private Long departmentId; @Column(nullable = false, unique = true, length = 25) private String email; @Id @Column(name="EMPLOYEE_ID", nullable = false) private Long employeeId; @Column(name="FIRST_NAME", length = 20) private String firstName; @Column(name="HIRE_DATE", nullable = false) private Timestamp hireDate; @Column(name="JOB_ID", nullable = false, length = 10) private String jobId; @Column(name="LAST_NAME", nullable = false, length = 25) private String lastName; @Column(name="PHONE_NUMBER", length = 20) private String phoneNumber; private Double salary; @ManyToOne @JoinColumn(name = "MANAGER_ID") private Employee employee; @OneToMany(mappedBy = "employee") private List employeeList; public Employee() { } public Employee(Double commissionPct, Long departmentId, String email, Long employeeId, String firstName, Timestamp hireDate, String jobId, String lastName, Employee employee, String phoneNumber, Double salary) { this.commissionPct = commissionPct; this.departmentId = departmentId; this.email = email; this.employeeId = employeeId; this.firstName = firstName; this.hireDate = hireDate; this.jobId = jobId; this.lastName = lastName; this.employee = employee; this.phoneNumber = phoneNumber; this.salary = salary; } public Double getCommissionPct() { return commissionPct; } public void setCommissionPct(Double commissionPct) { this.commissionPct = commissionPct; } public Long getDepartmentId() { return departmentId; } public void setDepartmentId(Long departmentId) { this.departmentId = departmentId; } public String getEmail() { return email; } public void setEmail(String email) { this.email = email; } public Long getEmployeeId() { return employeeId; } public void setEmployeeId(Long employeeId) { this.employeeId = employeeId; } public String getFirstName() { return firstName; } public void setFirstName(String firstName) { this.firstName = firstName; } public Timestamp getHireDate() { return hireDate; } public void setHireDate(Timestamp hireDate) { this.hireDate = hireDate; } public String getJobId() { return jobId; } public void setJobId(String jobId) { this.jobId = jobId; } public String getLastName() { return lastName; } public void setLastName(String lastName) { this.lastName = lastName; } public String getPhoneNumber() { return phoneNumber; } public void setPhoneNumber(String phoneNumber) { this.phoneNumber = phoneNumber; } public Double getSalary() { return salary; } public void setSalary(Double salary) { this.salary = salary; } public Employee getEmployee() { return employee; } public void setEmployee(Employee employee) { this.employee = employee; } public List getEmployeeList() { return employeeList; } public void setEmployeeList(List employeeList) { this.employeeList = employeeList; } public Employee addEmployee(Employee employee) { getEmployeeList().add(employee); employee.setEmployee(this); return employee; } public Employee removeEmployee(Employee employee) { getEmployeeList().remove(employee); employee.setEmployee(null); return employee; } } JPA could be used in standalone applications and Java EE containers. In both worlds you normally create a Facade to retrieve or store the values of the Entities to or from the database. The Facade does this via an EntityManager which will be injected by the Java EE container. Here is sample Facade Session Bean for a Java EE container. package demo.proxy.ejb; import java.util.HashMap; import java.util.List; import javax.ejb.Local; import javax.ejb.Remote; import javax.ejb.Stateless; import javax.persistence.EntityManager; import javax.persistence.PersistenceContext; import javax.persistence.Query; import javax.interceptor.AroundInvoke; import javax.interceptor.InvocationContext; import oracle.jdbc.driver.OracleConnection; import org.eclipse.persistence.config.EntityManagerProperties; import org.eclipse.persistence.internal.jpa.EntityManagerImpl; @Stateless(name = "DataFacade", mappedName = "ProxyUser-TestEJB-DataFacade") @Remote @Local public class DataFacadeBean implements DataFacade, DataFacadeLocal { @PersistenceContext(unitName = "TestEJB") private EntityManager em; private String username; public Object queryByRange(String jpqlStmt, int firstResult, int maxResults) { // setSessionUser(); Query query = em.createQuery(jpqlStmt); if (firstResult 0) { query = query.setFirstResult(firstResult); } if (maxResults 0) { query = query.setMaxResults(maxResults); } return query.getResultList(); } public Employee persistEmployee(Employee employee) { // setSessionUser(); em.persist(employee); return employee; } public Employee mergeEmployee(Employee employee) { // setSessionUser(); return em.merge(employee); } public void removeEmployee(Employee employee) { // setSessionUser(); employee = em.find(Employee.class, employee.getEmployeeId()); em.remove(employee); } /** select o from Employee o */ public List getEmployeeFindAll() { Query q = em.createNamedQuery("Employee.findAll"); return q.getResultList(); } Putting Both Together To use Proxy Authentication with JPA and within a Java EE container you have to take care of the additional requirements: Use an OCI JDBC driver Provide the user name that connects through the proxy user Use an OCI JDBC driver To use the OCI JDBC driver you need to set up your JDBC data source file to use the correct JDBC URL. hr jdbc:oracle:oci8:@(DESCRIPTION=(ADDRESS=(PROTOCOL=TCP)(HOST=localhost)(PORT=1521))(CONNECT_DATA=(SID=XE))) oracle.jdbc.OracleDriver user app_user 62C32F70E98297522AD97E15439FAC0E SQL SELECT 1 FROM DUAL jdbc/hrDS Application Additionally you need to make sure that the version of the shared libraries of the OCI driver match the version of the JDBC driver in your Java EE container or Java application and are within your PATH (on Windows) or LD_LIBRARY_PATH (on most Unix-based systems). Installing the Oracle Database Instance Client software works perfectly. Provide the user name that connects through the proxy user This part needs some modification of your application software and session facade. Session Facade Changes In the Session Facade we must ensure that every call that goes through the EntityManager must be prepared correctly and uniquely assigned to this session. The second is really important, as the EntityManager works with a connection pool and can not guarantee that we set the proxy user on the connection that will be used for the database activities. To avoid changing every method call of the Session Facade we provide a method to set the username of the user that connects through the proxy user. This method needs to be called by the Facade client bfore doing anything else. public void setUsername(String name) { username = name; } Next we provide a means to instruct the TopLink EntityManager Delegate to use Oracle Proxy Authentication. (I love small helper methods to hide the nitty-gritty details and avoid repeating myself.) private void setSessionUser() { setSessionUser(username); } private void setSessionUser(String user) { if (user != null && !user.isEmpty()) { EntityManagerImpl emDelegate = ((EntityManagerImpl)em.getDelegate()); emDelegate.setProperty(EntityManagerProperties.ORACLE_PROXY_TYPE, OracleConnection.PROXYTYPE_USER_NAME); emDelegate.setProperty(OracleConnection.PROXY_USER_NAME, user); emDelegate.setProperty(EntityManagerProperties.EXCLUSIVE_CONNECTION_MODE, "Always"); } } The final step is use the EJB 3.0 AroundInvoke interceptor. This interceptor will be called around every method invocation. We therefore check whether the Facade methods will be called or not. If so, we set the user for proxy authentication and the normal method flow continues. @AroundInvoke public Object proxyInterceptor(InvocationContext invocationCtx) throws Exception { if (invocationCtx.getTarget() instanceof DataFacadeBean) { setSessionUser(); } return invocationCtx.proceed(); } Benefits Using Oracle Proxy Authentification has a number of additional benefits appart from implementing the role model of your application: Fine grained access control for temporary users of the account, without compromising the original password. Enabling database auditing and logging. Better identification of performance bottlenecks. References Effective Oracle Database 10g Security by Design, David Knox TopLink Developer's Guide, Chapter 98

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  • You should NOT be writing jQuery in SharePoint if&hellip;

    - by Mark Rackley
    Yes… another one of these posts. What can I say? I’m a pot stirrer.. a rabble rouser *rabble rabble* jQuery in SharePoint seems to be a fairly polarizing issue with one side thinking it is the most awesome thing since Princess Leia as the slave girl in Return of the Jedi and the other half thinking it is the worst idea since Mannequin 2: On the Move. The correct answer is OF COURSE “it depends”. But what are those deciding factors that make jQuery an awesome fit or leave a bad taste in your mouth? Let’s see if I can drive the discussion here with some polarizing comments of my own… I know some of you are getting ready to leave your comments even now before reading the rest of the blog, which is great! Iron sharpens iron… These discussions hopefully open us up to understanding the entire process better and think about things in a different way. You should not be writing jQuery in SharePoint if you are not a developer… Let’s start off with my most polarizing and rant filled portion of the blog post. If you don’t know what you are doing or you don’t have a background that helps you understand the implications of what you are writing then you should not be writing jQuery in SharePoint! I truly believe that one of the biggest reasons for the jQuery haters is because of all the bad jQuery out there. If you don’t know what you are doing you can do some NASTY things! One of the best stories I’ve heard about this is from my good friend John Ferringer (@ferringer). John tells this story during our Mythbusters session we do together. One of his clients was undergoing a Denial of Service attack and they couldn’t figure out what was going on! After much searching they found that some genius jQuery developer wrote some code for an image rotator, but did not take into account what happens when there are no images to load! The code just kept hitting the servers over and over and over again which prevented anything else from getting done! Now, I’m NOT saying that I have not done the same sort of thing in the past or am immune from such mistakes. My point is that if you don’t know what you are doing, there are very REAL consequences that can have a major impact on your organization AND they will be hard to track down.  Think how happy your boss will be after you copy and pasted some jQuery from a blog without understanding what it does, it brings down the farm, AND it takes them 3 days to track it back to you.  :/ Good times will not be had. Like it or not JavaScript/jQuery is a programming language. While you .NET people sit on your high horses because your code is compiled and “runs faster” (also debatable), the rest of us will be actually getting work done and delivering solutions while you are trying to figure out why your widget won’t deploy. I can pick at that scab because I write .NET code too and speak from experience. I can do both, and do both well. So, I am not speaking from ignorance here. In JavaScript/jQuery you have variables, loops, conditionals, functions, arrays, events, and built in methods. If you are not a developer you just aren’t going to take advantage of all of that and use it correctly. Ahhh.. but there is hope! There is a lot of jQuery resources out there to help you learn and learn well! There are many experts on the subject that will gladly tell you when you are smoking crack. I just this minute saw a tweet from @cquick with a link to: “jQuery Fundamentals”. I just glanced through it and this may be a great primer for you aspiring jQuery devs. Take advantage of all the resources and become a developer! Hey, it will look awesome on your resume right? You should not be writing jQuery in SharePoint if it depends too much on client resources for a good user experience I’ve said it once and I’ll say it over and over until you understand. jQuery is executed on the client’s computer. Got it? If you are looping through hundreds of rows of data, searching through an enormous DOM, or performing many calculations it is going to take some time! AND if your user happens to be sitting on some old PC somewhere that they picked up at a garage sale their experience will be that much worse! If you can’t give the user a good experience they will not use the site. So, if jQuery is causing the user to have a bad experience, don’t use it. I sometimes go as far to say that you should NOT go to jQuery as a first option for external facing web sites because you have ZERO control over what the end user’s computer will be. You just can’t guarantee an awesome user experience all of the time. Ahhh… but you have no choice? (where have I heard that before?). Well… if you really have no choice, here are some tips to help improve the experience: Avoid screen scraping This is not 1999 and SharePoint is not an old green screen from a mainframe… so why are you treating it like it is? Screen scraping is time consuming and client intensive. Take advantage of tools like SPServices to do your data retrieval when possible. Fine tune your DOM searches A lot of time can be eaten up just searching the DOM and ignoring table rows that you don’t need. Write better jQuery to only loop through tables rows that you need, or only access specific elements you need. Take advantage of Element ID’s to return the one element you are looking for instead of looping through all the DOM over and over again. Write better jQuery Remember this is development. Think about how you can write cleaner, faster jQuery. This directly relates to the previous point of improving your DOM searches, but also when using arrays, variables and loops. Do you REALLY need to loop through that array 3 times? How can you knock it down to 2 times or even 1? When you have lots of calculations and data that you are manipulating every operation adds up. Think about how you can streamline it. Back in the old days before RAM was abundant, Cores were plentiful and dinosaurs roamed the earth, us developers had to take performance into account in everything we did. It’s a lost art that really needs to be used here. You should not be writing jQuery in SharePoint if you are sending a lot of data over the wire… Developer:  “Awesome… you can easily call SharePoint’s web services to retrieve and write data using SPServices!” Administrator: “Crap! you can easily call SharePoint’s web services to retrieve and write data using SPServices!” SPServices may indeed be the best thing that happened to SharePoint since the invention of SharePoint Saturdays by Godfather Lotter… BUT you HAVE to use it wisely! (I REFUSE to make the Spiderman reference). If you do not know what you are doing your code will bring back EVERY field and EVERY row from a list and push that over the internet with all that lovely XML wrapped around it. That can be a HUGE amount of data and will GREATLY impact performance! Calling several web service methods at the same time can cause the same problem and can negatively impact your SharePoint servers. These problems, thankfully, are not difficult to rectify if you are careful: Limit list data retrieved Use CAML to reduce the number of rows returned and limit the fields returned using ViewFields.  You should definitely be doing this regardless. If you aren’t I hope your admin thumps you upside the head. Batch large list updates You may or may not have noticed that if you try to do large updates (hundreds of rows) that the performance is either completely abysmal or it fails over half the time. You can greatly improve performance and avoid timeouts by breaking up your updates into several smaller updates. I don’t know if there is a magic number for best performance, it really depends on how much data you are sending back more than the number of rows. However, I have found that 200 rows generally works well.  Play around and find the right number for your situation. Delay Web Service calls when possible One of the cool things about jQuery and SPServices is that you can delay queries to the server until they are actually needed instead of doing them all at once. This can lead to performance improvements over DataViewWebParts and even .NET code in the right situations. So, don’t load the data until it’s needed. In some instances you may not need to retrieve the data at all, so why retrieve it ALL the time? You should not be writing jQuery in SharePoint if there is a better solution… jQuery is NOT the silver bullet in SharePoint, it is not the answer to every question, it is just another tool in the developers toolkit. I urge all developers to know what options exist out there and choose the right one! Sometimes it will be jQuery, sometimes it will be .NET,  sometimes it will be XSL, and sometimes it will be some other choice… So, when is there a better solution to jQuery? When you can’t get away from performance problems Sometimes jQuery will just give you horrible performance regardless of what you do because of unavoidable obstacles. In these situations you are going to have to figure out an alternative. Can I do it with a DVWP or do I have to crack open Visual Studio? When you need to do something that jQuery can’t do There are lots of things you can’t do in jQuery like elevate privileges, event handlers, workflows, or interact with back end systems that have no web service interface. It just can’t do everything. When it can be done faster and more efficiently another way Why are you spending time to write jQuery to do a DataViewWebPart that would take 5 minutes? Or why are you trying to implement complicated logic that would be simple to do in .NET? If your answer is that you don’t have the option, okay. BUT if you do have the option don’t reinvent the wheel! Take advantage of the other tools. The answer is not always jQuery… sorry… the kool-aid tastes good, but sweet tea is pretty awesome too. You should not be using jQuery in SharePoint if you are a moron… Let’s finish up the blog on a high note… Yes.. it’s true, I sometimes type things just to get a reaction… guess this section title might be a good example, but it feels good sometimes just to type the words that a lot of us think… So.. don’t be that guy! Another good buddy of mine that works for Microsoft told me. “I loved jQuery in SharePoint…. until I had to support it.”. He went on to explain that some user was making several web service calls on a page using jQuery and then was calling Microsoft and COMPLAINING because the page took so long to load… DUH! What do you expect to happen when you are pushing that much data over the wire and are making that many web service calls at once!! It’s one thing to write that kind of code and accept it’s just going to take a while, it’s COMPLETELY another issue to do that and then complain when it’s not lightning fast!  Someone’s gene pool needs some chlorine. So, I think this is a nice summary of the blog… DON’T be that guy… don’t be a moron. How can you stop yourself from being a moron? Ah.. glad you asked, here are some tips: Think Is jQuery the right solution to my problem? Is there a better approach? What are the implications and pitfalls of using jQuery in this situation? Search What are others doing? Does someone have a better solution? Is there a third party library that does the same thing I need? Plan Write good jQuery. Limit calculations and data sent over the wire and don’t reinvent the wheel when possible. Test Okay, it works well on your machine. Try it on others ESPECIALLY if this is for an external site. Test with empty data. Test with hundreds of rows of data. Test as many scenarios as possible. Monitor those server resources to see the impact there as well. Ask the experts As smart as you are, there are people smarter than you. Even the experts talk to each other to make sure they aren't doing something stupid. And for the MOST part they are pretty nice guys. Marc Anderson and Christophe Humbert are two guys who regularly keep me in line. Make sure you aren’t doing something stupid. Repeat So, when you think you have the best solution possible, repeat the steps above just to be safe.  Conclusion jQuery is an awesome tool and has come in handy on many occasions. I’m even teaching a 1/2 day SharePoint & jQuery workshop at the upcoming SPTechCon in Boston if you want to berate me in person. However, it’s only as awesome as the developer behind the keyboard. It IS development and has its pitfalls. Knowledge and experience are invaluable to giving the user the best experience possible.  Let’s face it, in the end, no matter our opinions, prejudices, or ego providing our clients, customers, and users with the best solution possible is what counts. Period… end of sentence…

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  • C#/.NET Fundamentals: Choosing the Right Collection Class

    - by James Michael Hare
    The .NET Base Class Library (BCL) has a wide array of collection classes at your disposal which make it easy to manage collections of objects. While it's great to have so many classes available, it can be daunting to choose the right collection to use for any given situation. As hard as it may be, choosing the right collection can be absolutely key to the performance and maintainability of your application! This post will look at breaking down any confusion between each collection and the situations in which they excel. We will be spending most of our time looking at the System.Collections.Generic namespace, which is the recommended set of collections. The Generic Collections: System.Collections.Generic namespace The generic collections were introduced in .NET 2.0 in the System.Collections.Generic namespace. This is the main body of collections you should tend to focus on first, as they will tend to suit 99% of your needs right up front. It is important to note that the generic collections are unsynchronized. This decision was made for performance reasons because depending on how you are using the collections its completely possible that synchronization may not be required or may be needed on a higher level than simple method-level synchronization. Furthermore, concurrent read access (all writes done at beginning and never again) is always safe, but for concurrent mixed access you should either synchronize the collection or use one of the concurrent collections. So let's look at each of the collections in turn and its various pros and cons, at the end we'll summarize with a table to help make it easier to compare and contrast the different collections. The Associative Collection Classes Associative collections store a value in the collection by providing a key that is used to add/remove/lookup the item. Hence, the container associates the value with the key. These collections are most useful when you need to lookup/manipulate a collection using a key value. For example, if you wanted to look up an order in a collection of orders by an order id, you might have an associative collection where they key is the order id and the value is the order. The Dictionary<TKey,TVale> is probably the most used associative container class. The Dictionary<TKey,TValue> is the fastest class for associative lookups/inserts/deletes because it uses a hash table under the covers. Because the keys are hashed, the key type should correctly implement GetHashCode() and Equals() appropriately or you should provide an external IEqualityComparer to the dictionary on construction. The insert/delete/lookup time of items in the dictionary is amortized constant time - O(1) - which means no matter how big the dictionary gets, the time it takes to find something remains relatively constant. This is highly desirable for high-speed lookups. The only downside is that the dictionary, by nature of using a hash table, is unordered, so you cannot easily traverse the items in a Dictionary in order. The SortedDictionary<TKey,TValue> is similar to the Dictionary<TKey,TValue> in usage but very different in implementation. The SortedDictionary<TKey,TValye> uses a binary tree under the covers to maintain the items in order by the key. As a consequence of sorting, the type used for the key must correctly implement IComparable<TKey> so that the keys can be correctly sorted. The sorted dictionary trades a little bit of lookup time for the ability to maintain the items in order, thus insert/delete/lookup times in a sorted dictionary are logarithmic - O(log n). Generally speaking, with logarithmic time, you can double the size of the collection and it only has to perform one extra comparison to find the item. Use the SortedDictionary<TKey,TValue> when you want fast lookups but also want to be able to maintain the collection in order by the key. The SortedList<TKey,TValue> is the other ordered associative container class in the generic containers. Once again SortedList<TKey,TValue>, like SortedDictionary<TKey,TValue>, uses a key to sort key-value pairs. Unlike SortedDictionary, however, items in a SortedList are stored as an ordered array of items. This means that insertions and deletions are linear - O(n) - because deleting or adding an item may involve shifting all items up or down in the list. Lookup time, however is O(log n) because the SortedList can use a binary search to find any item in the list by its key. So why would you ever want to do this? Well, the answer is that if you are going to load the SortedList up-front, the insertions will be slower, but because array indexing is faster than following object links, lookups are marginally faster than a SortedDictionary. Once again I'd use this in situations where you want fast lookups and want to maintain the collection in order by the key, and where insertions and deletions are rare. The Non-Associative Containers The other container classes are non-associative. They don't use keys to manipulate the collection but rely on the object itself being stored or some other means (such as index) to manipulate the collection. The List<T> is a basic contiguous storage container. Some people may call this a vector or dynamic array. Essentially it is an array of items that grow once its current capacity is exceeded. Because the items are stored contiguously as an array, you can access items in the List<T> by index very quickly. However inserting and removing in the beginning or middle of the List<T> are very costly because you must shift all the items up or down as you delete or insert respectively. However, adding and removing at the end of a List<T> is an amortized constant operation - O(1). Typically List<T> is the standard go-to collection when you don't have any other constraints, and typically we favor a List<T> even over arrays unless we are sure the size will remain absolutely fixed. The LinkedList<T> is a basic implementation of a doubly-linked list. This means that you can add or remove items in the middle of a linked list very quickly (because there's no items to move up or down in contiguous memory), but you also lose the ability to index items by position quickly. Most of the time we tend to favor List<T> over LinkedList<T> unless you are doing a lot of adding and removing from the collection, in which case a LinkedList<T> may make more sense. The HashSet<T> is an unordered collection of unique items. This means that the collection cannot have duplicates and no order is maintained. Logically, this is very similar to having a Dictionary<TKey,TValue> where the TKey and TValue both refer to the same object. This collection is very useful for maintaining a collection of items you wish to check membership against. For example, if you receive an order for a given vendor code, you may want to check to make sure the vendor code belongs to the set of vendor codes you handle. In these cases a HashSet<T> is useful for super-quick lookups where order is not important. Once again, like in Dictionary, the type T should have a valid implementation of GetHashCode() and Equals(), or you should provide an appropriate IEqualityComparer<T> to the HashSet<T> on construction. The SortedSet<T> is to HashSet<T> what the SortedDictionary<TKey,TValue> is to Dictionary<TKey,TValue>. That is, the SortedSet<T> is a binary tree where the key and value are the same object. This once again means that adding/removing/lookups are logarithmic - O(log n) - but you gain the ability to iterate over the items in order. For this collection to be effective, type T must implement IComparable<T> or you need to supply an external IComparer<T>. Finally, the Stack<T> and Queue<T> are two very specific collections that allow you to handle a sequential collection of objects in very specific ways. The Stack<T> is a last-in-first-out (LIFO) container where items are added and removed from the top of the stack. Typically this is useful in situations where you want to stack actions and then be able to undo those actions in reverse order as needed. The Queue<T> on the other hand is a first-in-first-out container which adds items at the end of the queue and removes items from the front. This is useful for situations where you need to process items in the order in which they came, such as a print spooler or waiting lines. So that's the basic collections. Let's summarize what we've learned in a quick reference table.  Collection Ordered? Contiguous Storage? Direct Access? Lookup Efficiency Manipulate Efficiency Notes Dictionary No Yes Via Key Key: O(1) O(1) Best for high performance lookups. SortedDictionary Yes No Via Key Key: O(log n) O(log n) Compromise of Dictionary speed and ordering, uses binary search tree. SortedList Yes Yes Via Key Key: O(log n) O(n) Very similar to SortedDictionary, except tree is implemented in an array, so has faster lookup on preloaded data, but slower loads. List No Yes Via Index Index: O(1) Value: O(n) O(n) Best for smaller lists where direct access required and no ordering. LinkedList No No No Value: O(n) O(1) Best for lists where inserting/deleting in middle is common and no direct access required. HashSet No Yes Via Key Key: O(1) O(1) Unique unordered collection, like a Dictionary except key and value are same object. SortedSet Yes No Via Key Key: O(log n) O(log n) Unique ordered collection, like SortedDictionary except key and value are same object. Stack No Yes Only Top Top: O(1) O(1)* Essentially same as List<T> except only process as LIFO Queue No Yes Only Front Front: O(1) O(1) Essentially same as List<T> except only process as FIFO   The Original Collections: System.Collections namespace The original collection classes are largely considered deprecated by developers and by Microsoft itself. In fact they indicate that for the most part you should always favor the generic or concurrent collections, and only use the original collections when you are dealing with legacy .NET code. Because these collections are out of vogue, let's just briefly mention the original collection and their generic equivalents: ArrayList A dynamic, contiguous collection of objects. Favor the generic collection List<T> instead. Hashtable Associative, unordered collection of key-value pairs of objects. Favor the generic collection Dictionary<TKey,TValue> instead. Queue First-in-first-out (FIFO) collection of objects. Favor the generic collection Queue<T> instead. SortedList Associative, ordered collection of key-value pairs of objects. Favor the generic collection SortedList<T> instead. Stack Last-in-first-out (LIFO) collection of objects. Favor the generic collection Stack<T> instead. In general, the older collections are non-type-safe and in some cases less performant than their generic counterparts. Once again, the only reason you should fall back on these older collections is for backward compatibility with legacy code and libraries only. The Concurrent Collections: System.Collections.Concurrent namespace The concurrent collections are new as of .NET 4.0 and are included in the System.Collections.Concurrent namespace. These collections are optimized for use in situations where multi-threaded read and write access of a collection is desired. The concurrent queue, stack, and dictionary work much as you'd expect. The bag and blocking collection are more unique. Below is the summary of each with a link to a blog post I did on each of them. ConcurrentQueue Thread-safe version of a queue (FIFO). For more information see: C#/.NET Little Wonders: The ConcurrentStack and ConcurrentQueue ConcurrentStack Thread-safe version of a stack (LIFO). For more information see: C#/.NET Little Wonders: The ConcurrentStack and ConcurrentQueue ConcurrentBag Thread-safe unordered collection of objects. Optimized for situations where a thread may be bother reader and writer. For more information see: C#/.NET Little Wonders: The ConcurrentBag and BlockingCollection ConcurrentDictionary Thread-safe version of a dictionary. Optimized for multiple readers (allows multiple readers under same lock). For more information see C#/.NET Little Wonders: The ConcurrentDictionary BlockingCollection Wrapper collection that implement producers & consumers paradigm. Readers can block until items are available to read. Writers can block until space is available to write (if bounded). For more information see C#/.NET Little Wonders: The ConcurrentBag and BlockingCollection Summary The .NET BCL has lots of collections built in to help you store and manipulate collections of data. Understanding how these collections work and knowing in which situations each container is best is one of the key skills necessary to build more performant code. Choosing the wrong collection for the job can make your code much slower or even harder to maintain if you choose one that doesn’t perform as well or otherwise doesn’t exactly fit the situation. Remember to avoid the original collections and stick with the generic collections.  If you need concurrent access, you can use the generic collections if the data is read-only, or consider the concurrent collections for mixed-access if you are running on .NET 4.0 or higher.   Tweet Technorati Tags: C#,.NET,Collecitons,Generic,Concurrent,Dictionary,List,Stack,Queue,SortedList,SortedDictionary,HashSet,SortedSet

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  • VS 2012 Code Review &ndash; Before Check In OR After Check In?

    - by Tarun Arora
    “Is Code Review Important and Effective?” There is a consensus across the industry that code review is an effective and practical way to collar code inconsistency and possible defects early in the software development life cycle. Among others some of the advantages of code reviews are, Bugs are found faster Forces developers to write readable code (code that can be read without explanation or introduction!) Optimization methods/tricks/productive programs spread faster Programmers as specialists "evolve" faster It's fun “Code review is systematic examination (often known as peer review) of computer source code. It is intended to find and fix mistakes overlooked in the initial development phase, improving both the overall quality of software and the developers' skills. Reviews are done in various forms such as pair programming, informal walkthroughs, and formal inspections.” Wikipedia No where does the definition mention whether its better to review code before the code has been committed to version control or after the commit has been performed. No matter which side you favour, Visual Studio 2012 allows you to request for a code review both before check in and also request for a review after check in. Let’s weigh the pros and cons of the approaches independently. Code Review Before Check In or Code Review After Check In? Approach 1 – Code Review before Check in Developer completes the code and feels the code quality is appropriate for check in to TFS. The developer raises a code review request to have a second pair of eyes validate if the code abides to the recommended best practices, will not result in any defects due to common coding mistakes and whether any optimizations can be made to improve the code quality.                                             Image 1 – code review before check in Pros Everything that gets committed to source control is reviewed. Minimizes the chances of smelly code making its way into the code base. Decreases the cost of fixing bugs, remember, the earlier you find them, the lesser the pain in fixing them. Cons Development Code Freeze – Since the changes aren’t in the source control yet. Further development can only be done off-line. The changes have not been through a CI build, hard to say whether the code abides to all build quality standards. Inconsistent! Cumbersome to track the actual code review process.  Not every change to the code base is worth reviewing, a lot of effort is invested for very little gain. Approach 2 – Code Review after Check in Developer checks in, random code reviews are performed on the checked in code.                                                      Image 2 – Code review after check in Pros The code has already passed the CI build and run through any code analysis plug ins you may have running on the build server. Instruct the developer to ensure ZERO fx cop, style cop and static code analysis before check in. Code is cleaner and smell free even before the code review. No Offline development, developers can continue to develop against the source control. Cons Bad code can easily make its way into the code base. Since the review take place much later in the cycle, the cost of fixing issues can prove to be much higher. Approach 3 – Hybrid Approach The community advocates a more hybrid approach, a blend of tooling and human accountability quotient.                                                               Image 3 – Hybrid Approach 1. Code review high impact check ins. It is not possible to review everything, by setting up code review check in policies you can end up slowing your team. More over, the code that you are reviewing before check in hasn't even been through a green CI build either. 2. Tooling. Let the tooling work for you. By running static analysis, fx cop, style cop and other plug ins on the build agent, you can identify the real issues that in my opinion can't possibly be identified using human reviews. Configure the tooling to report back top 10 issues every day. Mandate the manual code review of individuals who keep making it to this list of shame more often. 3. During Merge. I would prefer eliminating some of the other code issues during merge from Main branch to the release branch. In a scrum project this is still easier because cheery picking the merges is a possibility and the size of code being reviewed is still limited. Let the tooling work for you, if some one breaks the CI build often, put them on a gated check in build course until you see improvement. If some one appears on the top 10 list of shame generated via the build then ensure that all their code is reviewed till you see improvement. At the end of the day, the goal is to ensure that the code being delivered is top quality. By enforcing a code review before any check in, you force the developer to work offline or stay put till the review is complete. What do the experts say? So I asked a few expects what they thought of “Code Review quality gate before Checking in code?" Terje Sandstrom | Microsoft ALM MVP You mean a review quality gate BEFORE checking in code????? That would mean a lot of code staying either local or in shelvesets, and not even been through a CI build, and a green CI build being the main criteria for going further, f.e. to the review state. I would not like code laying around with no checkin’s. Having a requirement that code is checked in small pieces, 4-8 hours work max, and AT LEAST daily checkins, a manual code review comes second down the lane. I would expect review quality gates to happen before merging back to main, or before merging to release.  But that would all be on checked-in code.  Branching is absolutely one way to ease the pain.   Another way we are using is automatic quality builds, running metrics, coverage, static code analysis.  Unfortunately it takes some time, would be great to be on CI’s – but…., so it’s done scheduled every night. Based on this we get, among other stuff,  top 10 lists of suspicious code, which is then subjected to reviews.  If a person seems to be very popular on these top 10 lists, we subject every check in from that person to a review for a period. That normally helps.   None of the clients I have can afford to have every checkin reviewed, so we need to find ways around it. I don’t disagree with the nicety of having all the code reviewed, but I find it hard to find those resources in today’s enterprises. David V. Corbin | Visual Studio ALM Ranger I tend to agree with both sides. I hate having code that is not checked in, but at the same time hate having “bad” code in the repository. I have found that branching is one approach to solving this dilemma. Code is checked into the private/feature branch before the review, but is not merged over to the “official” branch until after the review. I advocate both, depending on circumstance (especially team dynamics)   - The “pre-checkin” is usually for elements that may impact the project as a whole. Think of it as another “gate” along with passing unit tests. - The “post-checkin” may very well not be at the changeset level, but correlates to a review at the “user story” level.   Again, this depends on team dynamics in play…. Robert MacLean | Microsoft ALM MVP I do not think there is no right answer for the industry as a whole. In short the question is why do you do reviews? Your question implies risk mitigation, so in low risk areas you can get away with it after check in while in high risk you need to do it before check in. An example is those new to a team or juniors need it much earlier (maybe that is before checkin, maybe that is soon after) than seniors who have shipped twenty sprints on the team. Abhimanyu Singhal | Visual Studio ALM Ranger Depends on per scenario basis. We recommend post check-in reviews when: 1. We don't want to block other checks and processes on manual code reviews. Manual reviews take time, and some pieces may not require manual reviews at all. 2. We need to trace all changes and track history. 3. We have a code promotion strategy/process in place. For risk mitigation, post checkin code can be promoted to Accepted branches. Or can be rejected. Pre Checkin Reviews are used when 1. There is a high risk factor associated 2. Reviewers are generally (most of times) have immediate availability. 3. Team does not have strict tracking needs. Simply speaking, no single process fits all scenarios. You need to select what works best for your team/project. Thomas Schissler | Visual Studio ALM Ranger This is an interesting discussion, I’m right now discussing details about executing code reviews with my teams. I see and understand the aspects you brought in, but there is another side as well, I’d like to point out. 1.) If you do reviews per check in this is not very practical as a hard rule because this will disturb the flow of the team very often or it will lead to reduce the checkin frequency of the devs which I would not accept. 2.) If you do later reviews, for example if you review PBIs, it is not easy to find out which code you should review. Either you review all changesets associate with the PBI, but then you might review code which has been changed with a later checkin and the dev maybe has already fixed the issue. Or you review the diff of the latest changeset of the PBI with the first but then you might also review changes of other PBIs. Jakob Leander | Sr. Director, Avanade In my experience, manual code review: 1. Does not get done and at the very least does not get redone after changes (regardless of intentions at start of project) 2. When a project actually do it, they often do not do it right away = errors pile up 3. Requires a lot of time discussing/defining the standard and for the team to learn it However code review is very important since e.g. even small memory leaks in a high volume web solution have big consequences In the last years I have advocated following approach for code review - Architects up front do “at least one best practice example” of each type of component and tell the team. Copy from this one. This should include error handling, logging, security etc. - Dev lead on project continuously browse code to validate that the best practices are used. Especially that patterns etc. are not broken. You can do this formally after each sprint/iteration if you want. Once this is validated it is unlikely to “go bad” even during later code changes Agree with customer to rely on static code analysis from Visual Studio as the one and only coding standard. This has HUUGE benefits - You can easily tweak to reach the level you desire together with customer - It is easy to measure for both developers/management - It is 100% consistent across code base - It gets validated all the time so you never end up getting hammered by a customer review in the end - It is easy to tell the developer that you do not want code back unless it has zero errors = minimize communication You need to track this at least during nightly builds and make sure team sees total # issues. Do not allow #issues it to grow uncontrolled. On the project I run I require code analysis to have run on code before checkin (checkin rule). This means -  You have to have clean compile (or CA wont run) so this is extra benefit = very few broken builds - You can change a few of the rules to compile as errors instead of warnings. I often do this for “missing dispose” issues which you REALLY do not want in your app Tip: Place your custom CA rules files as part of solution. That  way it works when you do branching etc. (path to CA file is relative in VS) Some may argue that CA is not as good as manual inspection. But since manual inspection in reality suffers from the 3 issues in start it is IMO a MUCH better (and much cheaper) approach from helicopter perspective Tirthankar Dutta | Director, Avanade I think code review should be run both before and after check ins. There are some code metrics that are meant to be run on the entire codebase … Also, especially on multi-site projects, one should strive to architect in a way that lets men manage the framework while boys write the repetitive code… scales very well with the need to review less by containment and imposing architectural restrictions to emphasise the design. Bruno Capuano | Microsoft ALM MVP For code reviews (means peer reviews) in distributed team I use http://www.vsanywhere.com/default.aspx  David Jobling | Global Sr. Director, Avanade Peer review is the only way to scale and its a great practice for all in the team to learn to perform and accept. In my experience you soon learn who's code to watch more than others and tune the attention. Mikkel Toudal Kristiansen | Manager, Avanade If you have several branches in your code base, you will need to merge often. This requires manual merging, when a file has been changed in both branches. It offers a good opportunity to actually review to changed code. So my advice is: Merging between branches should be done as often as possible, it should be done by a senior developer, and he/she should perform a full code review of the code being merged. As for detecting architectural smells and code smells creeping into the code base, one really good third party tools exist: Ndepend (http://www.ndepend.com/, for static code analysis of the current state of the code base). You could also consider adding StyleCop to the solution. Jesse Houwing | Visual Studio ALM Ranger I gave a presentation on this subject on the TechDays conference in NL last year. See my presentation and slides here (talk in Dutch, but English presentation): http://blog.jessehouwing.nl/2012/03/did-you-miss-my-techdaysnl-talk-on-code.html  I’d like to add a few more points: - Before/After checking is mostly a trust issue. If you have a team that does diligent peer reviews and regularly talk/sit together or peer review, there’s no need to enforce a before-checkin policy. The peer peer-programming and regular feedback during development can take care of most of the review requirements as long as the team isn’t under stress. - Under stress, enforce pre-checkin reviews, it might sound strange, if you’re already under time or budgetary constraints, but it is under such conditions most real issues start to be created or pile up. - Use tools to catch most common errors, Code Analysis/FxCop was already mentioned. HP Fortify, Resharper, Coderush etc can help you there. There are also a lot of 3rd party rules you can add to Code Analysis. I’ve written a few myself (http://fccopcontrib.codeplex.com) and various teams from Microsoft have added their own rules (MSOCAF for SharePoint, WSSF for WCF). For common errors that keep cropping up, see if you can define a rule. It’s much easier. But more importantly make sure you have a good help page explaining *WHY* it's wrong. If you have small feature or developer branches/shelvesets, you might want to review pre-merge. It’s still better to do peer reviews and peer programming, but the most important thing is that bad quality code doesn’t make it into the important branch. So my philosophy: - Use tooling as much as possible. - Make sure the team understands the tooling and the importance of the things it flags. It’s too easy to just click suppress all to ignore the warnings. - Under stress, tighten process, it’s under stress that the problems of late reviews will really surface - Most importantly if you do reviews do them as early as possible, but never later than needed. In other words, pre-checkin/post checking doesn’t really matter, as long as the review is done before the code is released. It’ll just be much more expensive to fix any review outcomes the later you find them. --- I would love to hear what you think!

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  • Abstracting functionality

    - by Ralf Westphal
    Originally posted on: http://geekswithblogs.net/theArchitectsNapkin/archive/2014/08/22/abstracting-functionality.aspxWhat is more important than data? Functionality. Yes, I strongly believe we should switch to a functionality over data mindset in programming. Or actually switch back to it. Focus on functionality Functionality once was at the core of software development. Back when algorithms were the first thing you heard about in CS classes. Sure, data structures, too, were important - but always from the point of view of algorithms. (Niklaus Wirth gave one of his books the title “Algorithms + Data Structures” instead of “Data Structures + Algorithms” for a reason.) The reason for the focus on functionality? Firstly, because software was and is about doing stuff. Secondly because sufficient performance was hard to achieve, and only thirdly memory efficiency. But then hardware became more powerful. That gave rise to a new mindset: object orientation. And with it functionality was devalued. Data took over its place as the most important aspect. Now discussions revolved around structures motivated by data relationships. (John Beidler gave his book the title “Data Structures and Algorithms: An Object Oriented Approach” instead of the other way around for a reason.) Sure, this data could be embellished with functionality. But nevertheless functionality was second. When you look at (domain) object models what you mostly find is (domain) data object models. The common object oriented approach is: data aka structure over functionality. This is true even for the most modern modeling approaches like Domain Driven Design. Look at the literature and what you find is recommendations on how to get data structures right: aggregates, entities, value objects. I´m not saying this is what object orientation was invented for. But I´m saying that´s what I happen to see across many teams now some 25 years after object orientation became mainstream through C++, Delphi, and Java. But why should we switch back? Because software development cannot become truly agile with a data focus. The reason for that lies in what customers need first: functionality, behavior, operations. To be clear, that´s not why software is built. The purpose of software is to be more efficient than the alternative. Money mainly is spent to get a certain level of quality (e.g. performance, scalability, security etc.). But without functionality being present, there is nothing to work on the quality of. What customers want is functionality of a certain quality. ASAP. And tomorrow new functionality needs to be added, existing functionality needs to be changed, and quality needs to be increased. No customer ever wanted data or structures. Of course data should be processed. Data is there, data gets generated, transformed, stored. But how the data is structured for this to happen efficiently is of no concern to the customer. Ask a customer (or user) whether she likes the data structured this way or that way. She´ll say, “I don´t care.” But ask a customer (or user) whether he likes the functionality and its quality this way or that way. He´ll say, “I like it” (or “I don´t like it”). Build software incrementally From this very natural focus of customers and users on functionality and its quality follows we should develop software incrementally. That´s what Agility is about. Deliver small increments quickly and often to get frequent feedback. That way less waste is produced, and learning can take place much easier (on the side of the customer as well as on the side of developers). An increment is some added functionality or quality of functionality.[1] So as it turns out, Agility is about functionality over whatever. But software developers’ thinking is still stuck in the object oriented mindset of whatever over functionality. Bummer. I guess that (at least partly) explains why Agility always hits a glass ceiling in projects. It´s a clash of mindsets, of cultures. Driving software development by demanding small increases in functionality runs against thinking about software as growing (data) structures sprinkled with functionality. (Excuse me, if this sounds a bit broad-brush. But you get my point.) The need for abstraction In the end there need to be data structures. Of course. Small and large ones. The phrase functionality over data does not deny that. It´s not functionality instead of data or something. It´s just over, i.e. functionality should be thought of first. It´s a tad more important. It´s what the customer wants. That´s why we need a way to design functionality. Small and large. We need to be able to think about functionality before implementing it. We need to be able to reason about it among team members. We need to be able to communicate our mental models of functionality not just by speaking about them, but also on paper. Otherwise reasoning about it does not scale. We learned thinking about functionality in the small using flow charts, Nassi-Shneiderman diagrams, pseudo code, or UML sequence diagrams. That´s nice and well. But it does not scale. You can use these tools to describe manageable algorithms. But it does not work for the functionality triggered by pressing the “1-Click Order” on an amazon product page for example. There are several reasons for that, I´d say. Firstly, the level of abstraction over code is negligible. It´s essentially non-existent. Drawing a flow chart or writing pseudo code or writing actual code is very, very much alike. All these tools are about control flow like code is.[2] In addition all tools are computationally complete. They are about logic which is expressions and especially control statements. Whatever you code in Java you can fully (!) describe using a flow chart. And then there is no data. They are about control flow and leave out the data altogether. Thus data mostly is assumed to be global. That´s shooting yourself in the foot, as I hope you agree. Even if it´s functionality over data that does not mean “don´t think about data”. Right to the contrary! Functionality only makes sense with regard to data. So data needs to be in the picture right from the start - but it must not dominate the thinking. The above tools fail on this. Bottom line: So far we´re unable to reason in a scalable and abstract manner about functionality. That´s why programmers are so driven to start coding once they are presented with a problem. Programming languages are the only tool they´ve learned to use to reason about functional solutions. Or, well, there might be exceptions. Mathematical notation and SQL may have come to your mind already. Indeed they are tools on a higher level of abstraction than flow charts etc. That´s because they are declarative and not computationally complete. They leave out details - in order to deliver higher efficiency in devising overall solutions. We can easily reason about functionality using mathematics and SQL. That´s great. Except for that they are domain specific languages. They are not general purpose. (And they don´t scale either, I´d say.) Bummer. So to be more precise we need a scalable general purpose tool on a higher than code level of abstraction not neglecting data. Enter: Flow Design. Abstracting functionality using data flows I believe the solution to the problem of abstracting functionality lies in switching from control flow to data flow. Data flow very naturally is not about logic details anymore. There are no expressions and no control statements anymore. There are not even statements anymore. Data flow is declarative by nature. With data flow we get rid of all the limiting traits of former approaches to modeling functionality. In addition, nomen est omen, data flows include data in the functionality picture. With data flows, data is visibly flowing from processing step to processing step. Control is not flowing. Control is wherever it´s needed to process data coming in. That´s a crucial difference and needs some rewiring in your head to be fully appreciated.[2] Since data flows are declarative they are not the right tool to describe algorithms, though, I´d say. With them you don´t design functionality on a low level. During design data flow processing steps are black boxes. They get fleshed out during coding. Data flow design thus is more coarse grained than flow chart design. It starts on a higher level of abstraction - but then is not limited. By nesting data flows indefinitely you can design functionality of any size, without losing sight of your data. Data flows scale very well during design. They can be used on any level of granularity. And they can easily be depicted. Communicating designs using data flows is easy and scales well, too. The result of functional design using data flows is not algorithms (too low level), but processes. Think of data flows as descriptions of industrial production lines. Data as material runs through a number of processing steps to be analyzed, enhances, transformed. On the top level of a data flow design might be just one processing step, e.g. “execute 1-click order”. But below that are arbitrary levels of flows with smaller and smaller steps. That´s not layering as in “layered architecture”, though. Rather it´s a stratified design à la Abelson/Sussman. Refining data flows is not your grandpa´s functional decomposition. That was rooted in control flows. Refining data flows does not suffer from the limits of functional decomposition against which object orientation was supposed to be an antidote. Summary I´ve been working exclusively with data flows for functional design for the past 4 years. It has changed my life as a programmer. What once was difficult is now easy. And, no, I´m not using Clojure or F#. And I´m not a async/parallel execution buff. Designing the functionality of increments using data flows works great with teams. It produces design documentation which can easily be translated into code - in which then the smallest data flow processing steps have to be fleshed out - which is comparatively easy. Using a systematic translation approach code can mirror the data flow design. That way later on the design can easily be reproduced from the code if need be. And finally, data flow designs play well with object orientation. They are a great starting point for class design. But that´s a story for another day. To me data flow design simply is one of the missing links of systematic lightweight software design. There are also other artifacts software development can produce to get feedback, e.g. process descriptions, test cases. But customers can be delighted more easily with code based increments in functionality. ? No, I´m not talking about the endless possibilities this opens for parallel processing. Data flows are useful independently of multi-core processors and Actor-based designs. That´s my whole point here. Data flows are good for reasoning and evolvability. So forget about any special frameworks you might need to reap benefits from data flows. None are necessary. Translating data flow designs even into plain of Java is possible. ?

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  • Pain Comes Instantly

    - by user701213
    When I look back at recent blog entries – many of which are not all that current (more on where my available writing time is going later) – I am struck by how many of them focus on public policy or legislative issues instead of, say, the latest nefarious cyberattack or exploit (or everyone’s favorite new pastime: coining terms for the Coming Cyberpocalypse: “digital Pearl Harbor” is so 1941). Speaking of which, I personally hope evil hackers from Malefactoria will someday hack into my bathroom scale – which in a future time will be connected to the Internet because, gosh, wouldn’t it be great to have absolutely everything in your life Internet-enabled? – and recalibrate it so I’m 10 pounds thinner. The horror. In part, my focus on public policy is due to an admitted limitation of my skill set. I enjoy reading technical articles about exploits and cybersecurity trends, but writing a blog entry on those topics would take more research than I have time for and, quite honestly, doesn’t play to my strengths. The first rule of writing is “write what you know.” The bigger contributing factor to my recent paucity of blog entries is that more and more of my waking hours are spent engaging in “thrust and parry” activity involving emerging regulations of some sort or other. I’ve opined in earlier blogs about what constitutes good and reasonable public policy so nobody can accuse me of being reflexively anti-regulation. That said, you have so many cycles in the day, and most of us would rather spend it slaying actual dragons than participating in focus groups on whether dragons are really a problem, whether lassoing them (with organic, sustainable and recyclable lassos) is preferable to slaying them – after all, dragons are people, too - and whether we need lasso compliance auditors to make sure lassos are being used correctly and humanely. (A point that seems to evade many rule makers: slaying dragons actually accomplishes something, whereas talking about “approved dragon slaying procedures and requirements” wastes the time of those who are competent to dispatch actual dragons and who were doing so very well without the input of “dragon-slaying theorists.”) Unfortunately for so many of us who would just get on with doing our day jobs, cybersecurity is rapidly devolving into the “focus groups on dragon dispatching” realm, which actual dragons slayers have little choice but to participate in. The general trend in cybersecurity is that powers-that-be – which encompasses groups other than just legislators – are often increasingly concerned and therefore feel they need to Do Something About Cybersecurity. Many seem to believe that if only we had the right amount of regulation and oversight, there would be no data breaches: a breach simply must mean Someone Is At Fault and Needs Supervision. (Leaving aside the fact that we have lots of home invasions despite a) guard dogs b) liberal carry permits c) alarm systems d) etc.) Also note that many well-managed and security-aware organizations, like the US Department of Defense, still get hacked. More specifically, many powers-that-be feel they must direct industry in a multiplicity of ways, up to and including how we actually build and deploy information technology systems. The more prescriptive the requirement, the more regulators or overseers a) can be seen to be doing something b) feel as if they are doing something regardless of whether they are actually doing something useful or cost effective. Note: an unfortunate concomitant of Doing Something is that often the cure is worse than the ailment. That is, doing what overseers want creates unfortunate byproducts that they either didn’t foresee or worse, don’t care about. After all, the logic goes, we Did Something. Prescriptive practice in the IT industry is problematic for a number of reasons. For a start, prescriptive guidance is really only appropriate if: • It is cost effective• It is “current” (meaning, the guidance doesn’t require the use of the technical equivalent of buggy whips long after horse-drawn transportation has become passé)*• It is practical (that is, pragmatic, proven and effective in the real world, not theoretical and unproven)• It solves the right problem With the above in mind, heading up the list of “you must be joking” regulations are recent disturbing developments in the Payment Card Industry (PCI) world. I’d like to give PCI kahunas the benefit of the doubt about their intentions, except that efforts by Oracle among others to make them aware of “unfortunate side effects of your requirements” – which is as tactful I can be for reasons that I believe will become obvious below - have gone, to-date, unanswered and more importantly, unchanged. A little background on PCI before I get too wound up. In 2008, the Payment Card Industry (PCI) Security Standards Council (SSC) introduced the Payment Application Data Security Standard (PA-DSS). That standard requires vendors of payment applications to ensure that their products implement specific requirements and undergo security assessment procedures. In order to have an application listed as a Validated Payment Application (VPA) and available for use by merchants, software vendors are required to execute the PCI Payment Application Vendor Release Agreement (VRA). (Are you still with me through all the acronyms?) Beginning in August 2010, the VRA imposed new obligations on vendors that are extraordinary and extraordinarily bad, short-sighted and unworkable. Specifically, PCI requires vendors to disclose (dare we say “tell all?”) to PCI any known security vulnerabilities and associated security breaches involving VPAs. ASAP. Think about the impact of that. PCI is asking a vendor to disclose to them: • Specific details of security vulnerabilities • Including exploit information or technical details of the vulnerability • Whether or not there is any mitigation available (as in a patch) PCI, in turn, has the right to blab about any and all of the above – specifically, to distribute all the gory details of what is disclosed - to the PCI SSC, qualified security assessors (QSAs), and any affiliate or agent or adviser of those entities, who are in turn permitted to share it with their respective affiliates, agents, employees, contractors, merchants, processors, service providers and other business partners. This assorted crew can’t be more than, oh, hundreds of thousands of entities. Does anybody believe that several hundred thousand people can keep a secret? Or that several hundred thousand people are all equally trustworthy? Or that not one of the people getting all that information would blab vulnerability details to a bad guy, even by accident? Or be a bad guy who uses the information to break into systems? (Wait, was that the Easter Bunny that just hopped by? Bringing world peace, no doubt.) Sarcasm aside, common sense tells us that telling lots of people a secret is guaranteed to “unsecret” the secret. Notably, being provided details of a vulnerability (without a patch) is of little or no use to companies running the affected application. Few users have the technological sophistication to create a workaround, and even if they do, most workarounds break some other functionality in the application or surrounding environment. Also, given the differences among corporate implementations of any application, it is highly unlikely that a single workaround is going to work for all corporate users. So until a patch is developed by the vendor, users remain at risk of exploit: even more so if the details of vulnerability have been widely shared. Sharing that information widely before a patch is available therefore does not help users, and instead helps only those wanting to exploit known security bugs. There’s a shocker for you. Furthermore, we already know that insider information about security vulnerabilities inevitably leaks, which is why most vendors closely hold such information and limit dissemination until a patch is available (and frequently limit dissemination of technical details even with the release of a patch). That’s the industry norm, not that PCI seems to realize or acknowledge that. Why would anybody release a bunch of highly technical exploit information to a cast of thousands, whose only “vetting” is that they are members of a PCI consortium? Oracle has had personal experience with this problem, which is one reason why information on security vulnerabilities at Oracle is “need to know” (we use our own row level access control to limit access to security bugs in our bug database, and thus less than 1% of development has access to this information), and we don’t provide some customers with more information than others or with vulnerability information and/or patches earlier than others. Failure to remember “insider information always leaks” creates problems in the general case, and has created problems for us specifically. A number of years ago, one of the UK intelligence agencies had information about a non-public security vulnerability in an Oracle product that they circulated among other UK and Commonwealth defense and intelligence entities. Nobody, it should be pointed out, bothered to report the problem to Oracle, even though only Oracle could produce a patch. The vulnerability was finally reported to Oracle by (drum roll) a US-based commercial company, to whom the information had leaked. (Note: every time I tell this story, the MI-whatever agency that created the problem gets a bit shirty with us. I know they meant well and have improved their vulnerability handling/sharing processes but, dudes, next time you find an Oracle vulnerability, try reporting it to us first before blabbing to lots of people who can’t actually fix the problem. Thank you!) Getting back to PCI: clearly, these new disclosure obligations increase the risk of exploitation of a vulnerability in a VPA and thus, of misappropriation of payment card data and customer information that a VPA processes, stores or transmits. It stands to reason that VRA’s current requirement for the widespread distribution of security vulnerability exploit details -- at any time, but particularly before a vendor can issue a patch or a workaround -- is very poor public policy. It effectively publicizes information of great value to potential attackers while not providing compensating benefits - actually, any benefits - to payment card merchants or consumers. In fact, it magnifies the risk to payment card merchants and consumers. The risk is most prominent in the time before a patch has been released, since customers often have little option but to continue using an application or system despite the risks. However, the risk is not limited to the time before a patch is issued: customers often need days, or weeks, to apply patches to systems, based upon the complexity of the issue and dependence on surrounding programs. Rather than decreasing the available window of exploit, this requirement increases the available window of exploit, both as to time available to exploit a vulnerability and the ease with which it can be exploited. Also, why would hackers focus on finding new vulnerabilities to exploit if they can get “EZHack” handed to them in such a manner: a) a vulnerability b) in a payment application c) with exploit code: the “Hacking Trifecta!“ It’s fair to say that this is probably the exact opposite of what PCI – or any of us – would want. Established industry practice concerning vulnerability handling avoids the risks created by the VRA’s vulnerability disclosure requirements. Specifically, the norm is not to release information about a security bug until the associated patch (or a pretty darn good workaround) has been issued. Once a patch is available, the notice to the user community is a high-level communication discussing the product at issue, the level of risk associated with the vulnerability, and how to apply the patch. The notices do not include either the specific customers affected by the vulnerability or forensic reports with maps of the exploit (both of which are required by the current VRA). In this way, customers have the tools they need to prioritize patching and to help prevent an attack, and the information released does not increase the risk of exploit. Furthermore, many vendors already use industry standards for vulnerability description: Common Vulnerability Enumeration (CVE) and Common Vulnerability Scoring System (CVSS). CVE helps ensure that customers know which particular issues a patch addresses and CVSS helps customers determine how severe a vulnerability is on a relative scale. Industry already provides the tools customers need to know what the patch contains and how bad the problem is that the patch remediates. So, what’s a poor vendor to do? Oracle is reaching out to other vendors subject to PCI and attempting to enlist then in a broad effort to engage PCI in rethinking (that is, eradicating) these requirements. I would therefore urge all who care about this issue, but especially those in the vendor community whose applications are subject to PCI and who may not have know they were being asked to tell-all to PCI and put their customers at risk, to do one of the following: • Contact PCI with your concerns• Contact Oracle (we are looking for vendors to sign our statement of concern)• And make sure you tell your customers that you have to rat them out to PCI if there is a breach involving the payment application I like to be charitable and say “PCI meant well” but in as important a public policy issue as what you disclose about vulnerabilities, to whom and when, meaning well isn’t enough. We need to do well. PCI, as regards this particular issue, has not done well, and has compounded the error by thus far being nonresponsive to those of us who have labored mightily to try to explain why they might want to rethink telling the entire planet about security problems with no solutions. By Way of Explanation… Non-related to PCI whatsoever, and the explanation for why I have not been blogging a lot recently, I have been working on Other Writing Venues with my sister Diane (who has also worked in the tech sector, inflicting upgrades on unsuspecting and largely ungrateful end users). I am pleased to note that we have recently (self-)published the first in the Miss Information Technology Murder Mystery series, Outsourcing Murder. The genre might best be described as “chick lit meets geek scene.” Our sisterly nom de plume is Maddi Davidson and (shameless plug follows): you can order the paper version of the book on Amazon, or the Kindle or Nook versions on www.amazon.com or www.bn.com, respectively. From our book jacket: Emma Jones, a 20-something IT consultant, is working on an outsourcing project at Tahiti Tacos, a restaurant chain offering Polynexican cuisine: refried poi, anyone? Emma despises her boss Padmanabh, a brilliant but arrogant partner in GD Consulting. When Emma discovers His-Royal-Padness’s body (verdict: death by cricket bat), she becomes a suspect.With her overprotective family and her best friend Stacey providing endless support and advice, Emma stumbles her way through an investigation of Padmanabh’s murder, bolstered by fusion food feeding frenzies, endless cups of frou-frou coffee and serious surfing sessions. While Stacey knows a PI who owes her a favor, landlady Magda urges Emma to tart up her underwear drawer before the next cute cop with a search warrant arrives. Emma’s mother offers to fix her up with a PhD student at Berkeley and showers her with self-defense gizmos while her old lover Keoni beckons from Hawai’i. And everyone, even Shaun the barista, knows a good lawyer. Book 2, Denial of Service, is coming out this summer. * Given the rate of change in technology, today’s “thou shalts” are easily next year’s “buggy whip guidance.”

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  • DevConnections Session Slides, Samples and Links

    - by Rick Strahl
    Finally coming up for air this week, after catching up with being on the road for the better part of three weeks. Here are my slides, samples and links for my four DevConnections Session two weeks ago in Vegas. I ended up doing one extra un-prepared for session on WebAPI and AJAX, as some of the speakers were either delayed or unable to make it at all to Vegas due to Sandy's mayhem. It was pretty hectic in the speaker room as Erik (our event coordinator extrodinaire) was scrambling to fill session slots with speakers :-). Surprisingly it didn't feel like the storm affected attendance drastically though, but I guess it's hard to tell without actual numbers. The conference was a lot of fun - it's been a while since I've been speaking at one of these larger conferences. I'd been taking a hiatus, and I forgot how much I enjoy actually giving talks. Preparing - well not  quite so much, especially since I ended up essentially preparing or completely rewriting for all three of these talks and I was stressing out a bit as I was sick the week before the conference and didn't get as much time to prepare as I wanted to. But - as always seems to be the case - it all worked out, but I guess those that attended have to be the judge of that… It was great to catch up with my speaker friends as well - man I feel out of touch. I got to spend a bunch of time with Dan Wahlin, Ward Bell, Julie Lerman and for about 10 minutes even got to catch up with the ever so busy Michele Bustamante. Lots of great technical discussions including a fun and heated REST controversy with Ward and Howard Dierking. There were also a number of great discussions with attendees, describing how they're using the technologies touched in my talks in live applications. I got some great ideas from some of these and I wish there would have been more opportunities for these kinds of discussions. One thing I miss at these Vegas events though is some sort of coherent event where attendees and speakers get to mingle. These Vegas conferences are just like "go to sessions, then go out and PARTY on the town" - it's Vegas after all! But I think that it's always nice to have at least one evening event where everybody gets to hang out together and trade stories and geek talk. Overall there didn't seem to be much opportunity for that beyond lunch or the small and short exhibit hall events which it seemed not many people actually went to. Anyways, a good time was had. I hope those of you that came to my sessions learned something useful. There were lots of great questions and discussions after the sessions - always appreciate hearing the real life scenarios that people deal with in relation to the abstracted scenarios in sessions. Here are the Session abstracts, a few comments and the links for downloading slides and  samples. It's not quite like being there, but I hope this stuff turns out to be useful to some of you. I'll be following up a couple of these sessions with white papers in the following weeks. Enjoy. ASP.NET Architecture: How ASP.NET Works at the Low Level Abstract:Interested in how ASP.NET works at a low level? ASP.NET is extremely powerful and flexible technology, but it's easy to forget about the core framework that underlies the higher level technologies like ASP.NET MVC, WebForms, WebPages, Web Services that we deal with on a day to day basis. The ASP.NET core drives all the higher level handlers and frameworks layered on top of it and with the core power comes some complexity in the form of a very rich object model that controls the flow of a request through the ASP.NET pipeline from Windows HTTP services down to the application level. To take full advantage of it, it helps to understand the underlying architecture and model. This session discusses the architecture of ASP.NET along with a number of useful tidbits that you can use for building and debugging your ASP.NET applications more efficiently. We look at overall architecture, how requests flow from the IIS (7 and later) Web Server to the ASP.NET runtime into HTTP handlers, modules and filters and finally into high-level handlers like MVC, Web Forms or Web API. Focus of this session is on the low-level aspects on the ASP.NET runtime, with examples that demonstrate the bootstrapping of ASP.NET, threading models, how Application Domains are used, startup bootstrapping, how configuration files are applied and how all of this relates to the applications you write either using low-level tools like HTTP handlers and modules or high-level pages or services sitting at the top of the ASP.NET runtime processing chain. Comments:I was surprised to see so many people show up for this session - especially since it was the last session on the last day and a short 1 hour session to boot. The room was packed and it was to see so many people interested the abstracts of architecture of ASP.NET beyond the immediate high level application needs. Lots of great questions in this talk as well - I only wish this session would have been the full hour 15 minutes as we just a little short of getting through the main material (didn't make it to Filters and Error handling). I haven't done this session in a long time and I had to pretty much re-figure all the system internals having to do with the ASP.NET bootstrapping in light for the changes that came with IIS 7 and later. The last time I did this talk was with IIS6, I guess it's been a while. I love doing this session, mainly because in my mind the core of ASP.NET overall is so cleanly designed to provide maximum flexibility without compromising performance that has clearly stood the test of time in the 10 years or so that .NET has been around. While there are a lot of moving parts, the technology is easy to manage once you understand the core components and the core model hasn't changed much even while the underlying architecture that drives has been almost completely revamped especially with the introduction of IIS 7 and later. Download Samples and Slides   Introduction to using jQuery with ASP.NET Abstract:In this session you'll learn how to take advantage of jQuery in your ASP.NET applications. Starting with an overview of jQuery client features via many short and fun examples, you'll find out about core features like the power of selectors for document element selection, manipulating these elements with jQuery's wrapped set methods in a browser independent way, how to hook up and handle events easily and generally apply concepts of unobtrusive JavaScript principles to client scripting. The second half of the session then delves into jQuery's AJAX features and several different ways how you can interact with ASP.NET on the server. You'll see examples of using ASP.NET MVC for serving HTML and JSON AJAX content, as well as using the new ASP.NET Web API to serve JSON and hypermedia content. You'll also see examples of client side templating/databinding with Handlebars and Knockout. Comments:This session was in a monster of a room and to my surprise it was nearly packed, given that this was a 100 level session. I can see that it's a good idea to continue to do intro sessions to jQuery as there appeared to be quite a number of folks who had not worked much with jQuery yet and who most likely could greatly benefit from using it. Seemed seemed to me the session got more than a few people excited to going if they hadn't yet :-).  Anyway I just love doing this session because it's mostly live coding and highly interactive - not many sessions that I can build things up from scratch and iterate on in an hour. jQuery makes that easy though. Resources: Slides and Code Samples Introduction to jQuery White Paper Introduction to ASP.NET Web API   Hosting the Razor Scripting Engine in Your Own Applications Abstract:The Razor Engine used in ASP.NET MVC and ASP.NET Web Pages is a free-standing scripting engine that can be disassociated from these Web-specific implementations and can be used in your own applications. Razor allows for a powerful mix of code and text rendering that makes it a wonderful tool for any sort of text generation, from creating HTML output in non-Web applications, to rendering mail merge-like functionality, to code generation for developer tools and even as a plug-in scripting engine. In this session, we'll look at the components that make up the Razor engine and how you can bootstrap it in your own applications to hook up templating. You'll find out how to create custom templates and manage Razor requests that can be pre-compiled, detecting page changes and act in ways similar to a full runtime. We look at ways that you can pass data into the engine and retrieve both the rendered output as well as result values in a package that makes it easy to plug Razor into your own applications. Comments:That this session was picked was a bit of a surprise to me, since it's a bit of a niche topic. Even more of a surprise was that during the session quite a few people who attended had actually used Razor externally and were there to find out more about how the process works and how to extend it. In the session I talk a bit about a custom Razor hosting implementation (Westwind.RazorHosting) and drilled into the various components required to build a custom Razor Hosting engine and a runtime around it. This sessions was a bit of a chore to prepare for as there are lots of technical implementation details that needed to be dealt with and squeezing that into an hour 15 is a bit tight (and that aren't addressed even by some of the wrapper libraries that exist). Found out though that there's quite a bit of interest in using a templating engine outside of web applications, or often side by side with the HTML output generated by frameworks like MVC or WebForms. An extra fun part of this session was that this was my first session and when I went to set up I realized I forgot my mini-DVI to VGA adapter cable to plug into the projector in my room - 6 minutes before the session was about to start. So I ended up sprinting the half a mile + back to my room - and back at a full sprint. I managed to be back only a couple of minutes late, but when I started I was out of breath for the first 10 minutes or so, while trying to talk. Musta sounded a bit funny as I was trying to not gasp too much :-) Resources: Slides and Code Samples Westwind.RazorHosting GitHub Project Original RazorHosting Blog Post   Introduction to ASP.NET Web API for AJAX Applications Abstract:WebAPI provides a new framework for creating REST based APIs, but it can also act as a backend to typical AJAX operations. This session covers the core features of Web API as it relates to typical AJAX application development. We’ll cover content-negotiation, routing and a variety of output generation options as well as managing data updates from the client in the context of a small Single Page Application style Web app. Finally we’ll look at some of the extensibility features in WebAPI to customize and extend Web API in a number and useful useful ways. Comments:This session was a fill in for session slots not filled due MIA speakers stranded by Sandy. I had samples from my previous Web API article so decided to go ahead and put together a session from it. Given that I spent only a couple of hours preparing and putting slides together I was glad it turned out as it did - kind of just ran itself by way of the examples I guess as well as nice audience interactions and questions. Lots of interest - and also some confusion about when Web API makes sense. Both this session and the jQuery session ended up getting a ton of questions about when to use Web API vs. MVC, whether it would make sense to switch to Web API for all AJAX backend work etc. In my opinion there's no need to jump to Web API for existing applications that already have a good AJAX foundation. Web API is awesome for real externally consumed APIs and clearly defined application AJAX APIs. For typical application level AJAX calls, it's still a good idea, but ASP.NET MVC can serve most if not all of that functionality just as well. There's no need to abandon MVC (or even ASP.NET AJAX or third party AJAX backends) just to move to Web API. For new projects Web API probably makes good sense for isolation of AJAX calls, but it really depends on how the application is set up. In some cases sharing business logic between the HTML and AJAX interfaces with a single MVC API can be cleaner than creating two completely separate code paths to serve essentially the same business logic. Resources: Slides and Code Samples Sample Code on GitHub Introduction to ASP.NET Web API White Paper© Rick Strahl, West Wind Technologies, 2005-2012Posted in Conferences  ASP.NET   Tweet !function(d,s,id){var js,fjs=d.getElementsByTagName(s)[0];if(!d.getElementById(id)){js=d.createElement(s);js.id=id;js.src="//platform.twitter.com/widgets.js";fjs.parentNode.insertBefore(js,fjs);}}(document,"script","twitter-wjs"); (function() { var po = document.createElement('script'); po.type = 'text/javascript'; po.async = true; po.src = 'https://apis.google.com/js/plusone.js'; var s = document.getElementsByTagName('script')[0]; s.parentNode.insertBefore(po, s); })();

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