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  • How does braking assist of car racing games work?

    - by Ayush Khemka
    There are a lot of PC car racing games around which have this unique driving assist which helps brake your car so that you can safely turn it. While in some games it just an 'assist', it will just help your car brake but won't ensure a safe turn. While in others, the braking assist will help you get a safe turn. I was wondering on what could be the algorithm that is followed to achieve it. A very basic algorithm I could think of was, Pre-determine the braking distance of an ideal car for every turn of the track, depending on the radius of the turn, and then start braking the car accordingly. For example, for a turn of less than 90o, the car would start braking automatically at 50m distance from the start of the turn. A more advanced algorithm, which would ensure a safe turn, could be Pre-determine the speed of the car at the start of each turn, individually for each track, turn and car. Also, pre-determine the deceleration rate of each car individually, which varies because of the car's performance. The braking assist would keep recording the speed of the car at a certain instant of time. Start braking the car appropriately so that the car gets to the exact speed needed at the start of the turn. For example, let the speed of a particular car at the start of a turn 43m in radius, be 120km/h. Let the deceleration rate of the car be 200km/h2. If, at some instant of time, the speed of the car is 200km/h, then the car would automatically start braking at 400m from the start of the turn.

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  • Oracle VM Blade Cluster Reference Configuration

    - by Ferhat Hatay
    Today we are happy to announce the availability of the Oracle VM blade cluster reference configuration for Sun Blade 6000 modular systems.  The new Oracle VM blade cluster reference configuration can help reduce the time to deploy virtual infrastructure by up to 98 percent when compared to multi-vendor configurations. Oracle's virtualization strategy is to simplify the deployment, management, and support of the enterprise stack from application to disk. The Oracle VM blade cluster reference configuration is a single-vendor solution that addresses every layer of the virtualization stack with Oracle hardware and software components. It enables quick and easy deployment of the virtualized infrastructure using components that have been tested together and are all supported together by one vendor — Oracle. All components listed in the reference configuration have been tested together by Oracle, reducing the need for customer testing and the time-consuming and complex effort of designing and deploying a stable configuration. Benefitting from pre-installed Oracle VM Server for x86 software on Oracle’s highly scalable and reliable Sun Blade servers with built-in networking and Oracle’s Sun ZFS Storage Appliance product line, the configuration provides high availability via the blade cluster as well as a documented best practice guide that helps reduce deployment time and cost for customers implementing highly virtualized applications or private cloud Infrastructure as a Service (IaaS) architectures. To further support easier, faster and lower-cost deployments, Oracle Linux, Oracle Solaris and Oracle VM are available for pre-install on select Sun x86 systems, and Oracle VM Templates are available for download for Oracle Applications, Oracle Fusion Middleware, Oracle Database, Oracle Real Application Clusters, and many other Oracle products. Key benefits of the Oracle VM blade cluster reference configuration include: Faster time to value – Begin deploying applications immediately because the optimized software stack is pre-configured for best practices and is ready-to-run on the recommended hardware platforms. Reduced deployment cost and risk – The entire hardware and software stack has been tested and is supported together by Oracle. Elastic scalability – As capacity needs grow, the system can be easily scaled in multiple dimensions with the ability to add compute, storage, and networking resources independently. For more information, see: Oracle white paper: Accelerating deployment of virtualized infrastructures with the Oracle VM blade cluster reference configuration Oracle technical white paper: Best Practices and Guidelines for Deploying the Oracle VM Blade Cluster Reference Configuration

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  • Imperative vs. LINQ Performance on WP7

    - by Bil Simser
    Jesse Liberty had a nice post presenting the concepts around imperative, LINQ and fluent programming to populate a listbox. Check out the post as it’s a great example of some foundational things every .NET programmer should know. I was more interested in what the IL code that would be generated from imperative vs. LINQ was like and what the performance numbers are and how they differ. The code at the instruction level is interesting but not surprising. The imperative example with it’s creating lists and loops weighs in at about 60 instructions. .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } 1: .method private hidebysig instance void ImperativeMethod() cil managed 2: { 3: .maxstack 3 4: .locals init ( 5: [0] class [mscorlib]System.Collections.Generic.IEnumerable`1<int32> someData, 6: [1] class [mscorlib]System.Collections.Generic.List`1<int32> inLoop, 7: [2] int32 n, 8: [3] class [mscorlib]System.Collections.Generic.IEnumerator`1<int32> CS$5$0000, 9: [4] bool CS$4$0001) 10: L_0000: nop 11: L_0001: ldc.i4.1 12: L_0002: ldc.i4.s 50 13: L_0004: call class [mscorlib]System.Collections.Generic.IEnumerable`1<int32> [System.Core]System.Linq.Enumerable::Range(int32, int32) 14: L_0009: stloc.0 15: L_000a: newobj instance void [mscorlib]System.Collections.Generic.List`1<int32>::.ctor() 16: L_000f: stloc.1 17: L_0010: nop 18: L_0011: ldloc.0 19: L_0012: callvirt instance class [mscorlib]System.Collections.Generic.IEnumerator`1<!0> [mscorlib]System.Collections.Generic.IEnumerable`1<int32>::GetEnumerator() 20: L_0017: stloc.3 21: L_0018: br.s L_003a 22: L_001a: ldloc.3 23: L_001b: callvirt instance !0 [mscorlib]System.Collections.Generic.IEnumerator`1<int32>::get_Current() 24: L_0020: stloc.2 25: L_0021: nop 26: L_0022: ldloc.2 27: L_0023: ldc.i4.5 28: L_0024: cgt 29: L_0026: ldc.i4.0 30: L_0027: ceq 31: L_0029: stloc.s CS$4$0001 32: L_002b: ldloc.s CS$4$0001 33: L_002d: brtrue.s L_0039 34: L_002f: ldloc.1 35: L_0030: ldloc.2 36: L_0031: ldloc.2 37: L_0032: mul 38: L_0033: callvirt instance void [mscorlib]System.Collections.Generic.List`1<int32>::Add(!0) 39: L_0038: nop 40: L_0039: nop 41: L_003a: ldloc.3 42: L_003b: callvirt instance bool [mscorlib]System.Collections.IEnumerator::MoveNext() 43: L_0040: stloc.s CS$4$0001 44: L_0042: ldloc.s CS$4$0001 45: L_0044: brtrue.s L_001a 46: L_0046: leave.s L_005a 47: L_0048: ldloc.3 48: L_0049: ldnull 49: L_004a: ceq 50: L_004c: stloc.s CS$4$0001 51: L_004e: ldloc.s CS$4$0001 52: L_0050: brtrue.s L_0059 53: L_0052: ldloc.3 54: L_0053: callvirt instance void [mscorlib]System.IDisposable::Dispose() 55: L_0058: nop 56: L_0059: endfinally 57: L_005a: nop 58: L_005b: ldarg.0 59: L_005c: ldfld class [System.Windows]System.Windows.Controls.ListBox PerfTest.MainPage::LB1 60: L_0061: ldloc.1 61: L_0062: callvirt instance void [System.Windows]System.Windows.Controls.ItemsControl::set_ItemsSource(class [mscorlib]System.Collections.IEnumerable) 62: L_0067: nop 63: L_0068: ret 64: .try L_0018 to L_0048 finally handler L_0048 to L_005a 65: } 66:   67: Compare that to the IL generated for the LINQ version which has about half of the instructions and just gets the job done, no fluff. .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } 1: .method private hidebysig instance void LINQMethod() cil managed 2: { 3: .maxstack 4 4: .locals init ( 5: [0] class [mscorlib]System.Collections.Generic.IEnumerable`1<int32> someData, 6: [1] class [mscorlib]System.Collections.Generic.IEnumerable`1<int32> queryResult) 7: L_0000: nop 8: L_0001: ldc.i4.1 9: L_0002: ldc.i4.s 50 10: L_0004: call class [mscorlib]System.Collections.Generic.IEnumerable`1<int32> [System.Core]System.Linq.Enumerable::Range(int32, int32) 11: L_0009: stloc.0 12: L_000a: ldloc.0 13: L_000b: ldsfld class [System.Core]System.Func`2<int32, bool> PerfTest.MainPage::CS$<>9__CachedAnonymousMethodDelegate6 14: L_0010: brtrue.s L_0025 15: L_0012: ldnull 16: L_0013: ldftn bool PerfTest.MainPage::<LINQProgramming>b__4(int32) 17: L_0019: newobj instance void [System.Core]System.Func`2<int32, bool>::.ctor(object, native int) 18: L_001e: stsfld class [System.Core]System.Func`2<int32, bool> PerfTest.MainPage::CS$<>9__CachedAnonymousMethodDelegate6 19: L_0023: br.s L_0025 20: L_0025: ldsfld class [System.Core]System.Func`2<int32, bool> PerfTest.MainPage::CS$<>9__CachedAnonymousMethodDelegate6 21: L_002a: call class [mscorlib]System.Collections.Generic.IEnumerable`1<!!0> [System.Core]System.Linq.Enumerable::Where<int32>(class [mscorlib]System.Collections.Generic.IEnumerable`1<!!0>, class [System.Core]System.Func`2<!!0, bool>) 22: L_002f: ldsfld class [System.Core]System.Func`2<int32, int32> PerfTest.MainPage::CS$<>9__CachedAnonymousMethodDelegate7 23: L_0034: brtrue.s L_0049 24: L_0036: ldnull 25: L_0037: ldftn int32 PerfTest.MainPage::<LINQProgramming>b__5(int32) 26: L_003d: newobj instance void [System.Core]System.Func`2<int32, int32>::.ctor(object, native int) 27: L_0042: stsfld class [System.Core]System.Func`2<int32, int32> PerfTest.MainPage::CS$<>9__CachedAnonymousMethodDelegate7 28: L_0047: br.s L_0049 29: L_0049: ldsfld class [System.Core]System.Func`2<int32, int32> PerfTest.MainPage::CS$<>9__CachedAnonymousMethodDelegate7 30: L_004e: call class [mscorlib]System.Collections.Generic.IEnumerable`1<!!1> [System.Core]System.Linq.Enumerable::Select<int32, int32>(class [mscorlib]System.Collections.Generic.IEnumerable`1<!!0>, class [System.Core]System.Func`2<!!0, !!1>) 31: L_0053: stloc.1 32: L_0054: ldarg.0 33: L_0055: ldfld class [System.Windows]System.Windows.Controls.ListBox PerfTest.MainPage::LB2 34: L_005a: ldloc.1 35: L_005b: callvirt instance void [System.Windows]System.Windows.Controls.ItemsControl::set_ItemsSource(class [mscorlib]System.Collections.IEnumerable) 36: L_0060: nop 37: L_0061: ret 38: } Again, not surprising here but a good indicator that you should consider using LINQ where possible. In fact if you have ReSharper installed you’ll see a squiggly (technical term) in the imperative code that says “Hey Dude, I can convert this to LINQ if you want to be c00L!” (or something like that, it’s the 2010 geek version of Clippy). What about the fluent version? As Jon correctly pointed out in the comments, when you compare the IL for the LINQ code and the IL for the fluent code it’s the same. LINQ and the fluent interface are just syntactical sugar so you decide what you’re most comfortable with. At the end of the day they’re both the same. Now onto the numbers. Again I expected the imperative version to be better performing than the LINQ version (before I saw the IL that was generated). Call it womanly instinct. A gut feel. Whatever. Some of the numbers are interesting though. For Jesse’s example of 50 items, the numbers were interesting. The imperative sample clocked in at 7ms while the LINQ version completed in 4. As the number of items went up, the elapsed time didn’t necessarily climb exponentially. At 500 items they were pretty much the same and the results were similar up to about 50,000 items. After that I tried 500,000 items where the gap widened but not by much (2.2 seconds for imperative, 2.3 for LINQ). It wasn’t until I tried 5,000,000 items where things were noticeable. Imperative filled the list in 20 seconds while LINQ took 8 seconds longer (although personally I wouldn’t suggest you put 5 million items in a list unless you want your users showing up at your door with torches and pitchforks). Here’s the table with the full results. Method/Items 50 500 5,000 50,000 500,000 5,000,000 Imperative 7ms 7ms 38ms 223ms 2230ms 20974ms LINQ/Fluent 4ms 6ms 41ms 240ms 2310ms 28731ms Like I said, at the end of the day it’s not a huge difference and you really don’t want your users waiting around for 30 seconds on a mobile device filling lists. In fact if Windows Phone 7 detects you’re taking more than 10 seconds to do any one thing, it considers the app hung and shuts it down. The results here are for Windows Phone 7 but frankly they're the same for desktop and web apps so feel free to apply it generally. From a programming perspective, choose what you like. Some LINQ statements can get pretty hairy so I usually fall back with my simple mind and write it imperatively. If you really want to impress your friends, write it old school then let ReSharper do the hard work for! Happy programming!

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  • Oracle Certification at OpenWorld + JavaOne 2012 [VIDEO]

    - by Harold Green
    Oracle Certification will again be at this year's Oracle OpenWorld and JavaOne conferences in San Francisco. We'll have two locations - the Oracle Certification Lounge at OpenWorld, and the Java Certification Zone at JavaOne. Watch this quick video (1:46) to learn more about these, Oracle University pre-conference training, some mini-sessions on several certification topics, and previews of our new Exam Preparation Seminars. ORACLE CERTIFICATION PROGRAM LOUNGE Location: Moscone South, Mezzanine, Room 250 Hours: Monday, 9:00 a.m.–5:00 p.m. Tuesday, 9:00 a.m.–5:00 p.m. Wednesday, 9:00 a.m.–5:00 p.m. Thursday, 9:00 a.m.–1:00 p.m. JAVA CERTIFICATION ZONE Location: The Zone/Taylor Street Café Hours: Sunday, 7:00 p.m.–9:00 p.m. Monday, 11:00 a.m.–6:00 p.m. Tuesday, 11:00 a.m.–6:This i00 p.m. Wednesday, 11:00 a.m.–6:00 p.m. Thursday, 11:00 a.m.–2:00 p.m. CERTIFICATION SESSIONS Monday, 1:00 p.m - JavaOne (Java Certification Zone) Monday, 3:00 p.m - Oracle OpenWorld (Oracle Certification Lounge) QUICK LINKS: Oracle OpenWorld Certification Lounge Details Oracle University at Oracle OpenWorld 2012 (Pre-Conference Training) Java University at JavaOne 2012 (Pre-Conference Training) Self Test Software Oracle Press Oracle Certification on Twitter: https://twitter.com/oraclecert Oracle Certification on Facebook: facebook.com/OracleCertification

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  • What do Oracle VM Templates for JD Edwards EnterpriseOne 9.1 have to do with your Next Vacation!

    - by Monica Kumar
    Oracle VM Templates for JD Edwards EnterpriseOne 9.1 Update 2 and JD Edwards EnterpriseOne Tools 9.1.3.3 are now available for download from Oracle Software Delivery Cloud. So, what do Oracle VM Templates have to do with your next vacation? Well, how about time savings so you can plan for that next vacation and have the peace of mind since Oracle did the work and the testing for you!! What’s inside the new Oracle VM Templates release? The Oracle VM Templates for JD Edwards EnterpriseOne enables you to rapidly install JD Edwards EnterpriseOne. The complete stack includes: JD Edwards EnterpriseOne Applications Release 9.1 Update 2 JD Edwards EnterpriseOne Tools 9.1 Update 3, maintenance pack 3 (9.1.3.3) Oracle Database 11g Release 2 Oracle WebLogic Server 10.3.5 All pre-configured and pre-tested to run on Oracle Linux 5. Yes, the OS is included in the template! Oracle Business Intelligence Publisher 11.1.1.7.1 for use with JD Edwards EnterpriseOne One View Reporting JD Edwards EnterpriseOne Business Services Server and Oracle Application Development Framework (ADF) 11.1.1.5, for use with the JD Edwards EnterpriseOne Mobile Applications All pre-tuned to support up to 100 interactive users The templates can be installed to Oracle VM Server for x86 release 3.1 or later, to the Oracle Exalogic Elastic Cloud, and to the Oracle Database Appliance. Simply visit http://edelivery.oracle.com/oraclevm. Download and unzip the files and read the readme and you’re ready to go. How long would take you to install each of the components above, configure and tune them all from scratch? We know that you can get 7-10x faster deployment using the Oracle VM Templates. Now, how about that snorkeling trip to Belize!!

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  • Default Parameter in .NET 4(C#)

    - by Yousef_Jadallah
    During my using for the new release .NET 4, I notice that C# support default (Optional) Parameters, after thousands of complains form C# programmer- especially it was supported by VB.NET- now it's available. Let's create Test function with Optional Parameter   private void TestFunction(string para1, string para2 = "Default") { Response.Write("Parameter one =" + para1 +" , Parameter two="+ para2 ); } Then, if you try to call this method the Intellisense display likes this:   .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; }   Therefore,if you don’t pass the second parameter the value of para2 will be “Default”. With this new future in C#, you can ignore many overload functions event it was acceptable solution!

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  • Auto update for application hosted on multiple servers on cloud

    - by mots_g
    I'm working on an application which will run on multiple Amazon EC2 instances. I wish to incorporate auto update feature for my application. The updater should update all the Ec2 instances. Also, there is a central server which governs the creation/termination of EC2 instances as per load. The central server creates a EC2 new instance from a pre-configured custom AMI (custom image which has our application pre-installed). Also, once there is an update, the pre-configured AMI needs to be updated too else it would create new instances which are not updated. Should the central server notify all the ec2 instances for an update and then the instances update themselves?Or should the application on Ec2 instance have a check for periodically updating themselves? Also how should the Amazon custom AMI be updated? Should a new instance be created from it, updated and then a new AMI be re-created and then new images be created from this AMI? What is the best way to incorporate an auto update feature for this architecture? The central server is written in Java and the application running on the cloud is written in C++. Is there a good framework available that can be used for this architecture? Please let me know on what I could be missing in the design and how it would help me to have a nice, extensible and fail safe auto update architecture. Thanks

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  • rlwrap for wlst

    - by john.graves(at)oracle.com
    After reading Gilles’s post on using rlwrap for sql: http://blogs.oracle.com/xpsoluxdb/2011/03/bash-like_features_in_sqlplus_rman_and_other_oracle_command_line_tools.html It was obvious this would also be good for wlst. . $WL_HOME/server/bin/setWLSEnv.sh rlwrap -f wlst.words --multi-line java weblogic.WLST Here is my wlst.words file: http://blogs.oracle.com/johngraves/code/wlst.words .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; }

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  • Get a culture specific list of month names

    - by erwin21
    A while ago I found a clever way to retrieve a dynamic culture specific list of months names in C# with LINQ. 1: var months = Enumerable.Range(1, 12) 2: .Select(i => new 3: { 4: Month = i.ToString(), 5: MonthName = new DateTime(1, i, 1).ToString("MMMM") 6: }) 7: .ToList(); .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } It’s fairly simple, for a range of numbers from 1 to 12 a DateTime object is created (year and day doesn’t matter in this case), then the date time object formatted to a full month name with ToString(“MMMM”). In this example an anonymous object is created with a Month and MonthName property. You can use this solution to populate your dropdown list with months or to display a user friendly month name.

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  • WLS Console Timeout

    - by john.graves(at)oracle.com
    The WebLogic console timeout is a great feature for security, yet a horrible feature during development.  Logging in over and over again gets to be annoying.  This is very easy to change, but I would never do this on a production system!   Find the WebLogic consoleapp weblogic.xml file.  This is typically in your WL_HOME/server/lib/consoleapp/webapp/WEB-INF/ directory. Edit the weblogic.xml file: Update the section shown and increase the timeout-secs.  I just throw an extra zero at the end giving me ten full hours of fun!!!: <session-descriptor> <timeout-secs>36000</timeout-secs> <invalidation-interval-secs>60</invalidation-interval-secs> <cookie-name>ADMINCONSOLESESSION</cookie-name> <cookie-max-age-secs>-1</cookie-max-age-secs> <cookie-http-only>false</cookie-http-only> <url-rewriting-enabled>false</url-rewriting-enabled> </session-descriptor> .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; }

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  • Generic Pop and Push for List<T>

    - by Bil Simser
    Here's a little snippet I use to extend a generic List class to have similar capabilites to the Stack class. The Stack<T> class is great but it lives in its own world under System.Object. Wouldn't it be nice to have a List<T> that could do the same? Here's the code: .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: Consolas, "Courier New", Courier, Monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } 1: public static class ExtensionMethods 2: { 3: public static T Pop<T>(this List<T> theList) 4: { 5: var local = theList[theList.Count - 1]; 6: theList.RemoveAt(theList.Count - 1); 7: return local; 8: } 9:   10: public static void Push<T>(this List<T> theList, T item) 11: { 12: theList.Add(item); 13: } 14: } It's a simple extension but I've found it useful, hopefully you will too! Enjoy.

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  • JDBC Triggers

    - by Tim Dexter
    Received a question from a customer last week, they were using the new rollup patch on top of 10.1.3.4.1. What are these boxes for? Don't you know? Surely? Well, they are for ... that new functionality, you know it's in the user docs, that thingmabobby doodah. OK, I dont know either, I can have a guess but let me check first. Serveral IM sessions, emails and a dig through the readme for the new patch and I had my answer. Its not in the official documentation, yet. Leslie is on the case. The two fields were designed to allow an Admin to set a users context attributes before a connection is made to a database and for un-setting the attributes after the connection is broken by the extraction engine. We got a sample from the Enterprise Manager team on how they will be using it with their VPD connections. FUNCTION bip_to_em_user (user_name_in IN VARCHAR2) RETURN BOOLEAN IS BEGIN SETEMUSERCONTEXT(user_name_in, MGMT_USER.OP_SET_IDENTIFIER); return TRUE; END bip_to_em_user; And used in the jdbc data source definition like this (pre-process function): sysman.mgmt_bip.bip_to_em_user(:xdo_user_name) You, of course can call any function that is going to return a boolean value, another example might be. FUNCTION set_per_process_username (username_in IN VARCHAR2) RETURN BOOLEAN IS BEGIN SETUSERCONTEXT(username_in); return TRUE; END set_per_process_username Just use your own function/package to set some user context. Very grateful for the mail from Leslie on the EM team's usage but I had to try it out. Rather than set up a VPD, I opted for a simpler test. Can I log the comings and goings of users and their queries using the same pre-process text box. Reaching back into the depths of my developer brain to remember some pl/sql, it was not that deep and I came up with: CREATE OR REPLACE FUNCTION BIPTEST (user_name_in IN VARCHAR2, smode IN VARCHAR2) RETURN BOOLEAN AS BEGIN INSERT INTO LOGTAB VALUES(user_name_in, sysdate,smode); RETURN true; END BIPTEST; To call it in the pre-fetch trigger. BIPTEST(:xdo_user_name) Not going to set the pl/sql world alight I know, but you get the idea. As a new connection is made to the database its logged in the LOGTAB table. The SMODE value just sets if its an entry or an exit. I used the pre- and post- boxes. NAME UPDATE_DATE S_FLAG oracle 14-MAY-10 09.51.34.000000000 AM Start oracle 14-MAY-10 10.23.57.000000000 AM Finish administrator 14-MAY-10 09.51.38.000000000 AM Start administrator 14-MAY-10 09.51.38.000000000 AM Finish oracle 14-MAY-10 09.51.42.000000000 AM Start oracle 14-MAY-10 09.51.42.000000000 AM Finish It works very well, I had some fun trying to find a nasty query for the extraction engine so that the timestamps from in to out actually had a difference. That engine is fast! The only derived value you can pass from BIP is :xdo_user_name. None of the other server values are available. Connection pools are not currently supported but planned for a future release. Now you know what those fields are for and look for some official documentation, rather than my ramblings, coming soon!

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  • A faulty Caviar Blue hard drive?

    - by Glister
    We have a small "homemade" server running fully updated Debian Wheezy (amd64). One hard drive installed: WDC WD6400AAKS. The motherboard is ASUS M4N68T V2. The usual load: CPU: an average of 20% Each week about 50GB of additional space is occupied. About 47GB of uploaded files and 3GB of MySQL data. I'm afraid that the hard drive may be about to fail. I saw Pre-fail on few places when I ran: root@SERVER:/tmp# smartctl -a /dev/sda smartctl 5.41 2011-06-09 r3365 [x86_64-linux-3.2.0-4-amd64] (local build) Copyright (C) 2002-11 by Bruce Allen, http://smartmontools.sourceforge.net === START OF INFORMATION SECTION === Model Family: Western Digital Caviar Blue Serial ATA Device Model: WDC WD6400AAKS-XXXXXXX Serial Number: WD-XXXXXXXXXXXXXXXXXXX LU WWN Device Id: 5 0014ee XXXXXXXXXXXXX Firmware Version: 01.03B01 User Capacity: 640,135,028,736 bytes [640 GB] Sector Size: 512 bytes logical/physical Device is: In smartctl database [for details use: -P show] ATA Version is: 8 ATA Standard is: Exact ATA specification draft version not indicated Local Time is: Mon Oct 28 18:55:27 2013 UTC SMART support is: Available - device has SMART capability. SMART support is: Enabled === START OF READ SMART DATA SECTION === SMART overall-health self-assessment test result: PASSED General SMART Values: Offline data collection status: (0x85) Offline data collection activity was aborted by an interrupting command from host. Auto Offline Data Collection: Enabled. Self-test execution status: ( 247) Self-test routine in progress... 70% of test remaining. Total time to complete Offline data collection: (11580) seconds. Offline data collection capabilities: (0x7b) SMART execute Offline immediate. Auto Offline data collection on/off support. Suspend Offline collection upon new command. Offline surface scan supported. Self-test supported. Conveyance Self-test supported. Selective Self-test supported. SMART capabilities: (0x0003) Saves SMART data before entering power-saving mode. Supports SMART auto save timer. Error logging capability: (0x01) Error logging supported. General Purpose Logging supported. Short self-test routine recommended polling time: ( 2) minutes. Extended self-test routine recommended polling time: ( 136) minutes. Conveyance self-test routine recommended polling time: ( 5) minutes. SCT capabilities: (0x303f) SCT Status supported. SCT Error Recovery Control supported. SCT Feature Control supported. SCT Data Table supported. SMART Attributes Data Structure revision number: 16 Vendor Specific SMART Attributes with Thresholds: ID# ATTRIBUTE_NAME FLAG VALUE WORST THRESH TYPE UPDATED WHEN_FAILED RAW_VALUE 1 Raw_Read_Error_Rate 0x002f 200 200 051 Pre-fail Always - 0 3 Spin_Up_Time 0x0027 157 146 021 Pre-fail Always - 5108 4 Start_Stop_Count 0x0032 098 098 000 Old_age Always - 2968 5 Reallocated_Sector_Ct 0x0033 200 200 140 Pre-fail Always - 0 7 Seek_Error_Rate 0x002e 200 200 051 Old_age Always - 0 9 Power_On_Hours 0x0032 079 079 000 Old_age Always - 15445 10 Spin_Retry_Count 0x0032 100 100 051 Old_age Always - 0 11 Calibration_Retry_Count 0x0032 100 100 051 Old_age Always - 0 12 Power_Cycle_Count 0x0032 098 098 000 Old_age Always - 2950 192 Power-Off_Retract_Count 0x0032 200 200 000 Old_age Always - 426 193 Load_Cycle_Count 0x0032 200 200 000 Old_age Always - 2968 194 Temperature_Celsius 0x0022 111 095 000 Old_age Always - 36 196 Reallocated_Event_Count 0x0032 200 200 000 Old_age Always - 0 197 Current_Pending_Sector 0x0032 200 200 000 Old_age Always - 0 198 Offline_Uncorrectable 0x0030 200 200 000 Old_age Offline - 0 199 UDMA_CRC_Error_Count 0x0032 200 160 000 Old_age Always - 21716 200 Multi_Zone_Error_Rate 0x0008 200 200 051 Old_age Offline - 0 SMART Error Log Version: 1 No Errors Logged SMART Self-test log structure revision number 1 Num Test_Description Status Remaining LifeTime(hours) LBA_of_first_error # 1 Short offline Completed without error 00% 15444 - Error SMART Read Selective Self-Test Log failed: scsi error aborted command Smartctl: SMART Selective Self Test Log Read Failed root@SERVER:/tmp# In one tutorial I read that the pre-fail is a an indication of coming failure, in another tutorial I read that it is not true. Can you guys help me decode the output of smartctl? It would be also nice to share suggestions what should I do if I want to ensure data integrity (about 50GB of new data each week, up to 2TB for the whole period I'm interested in). Maybe I will go with 2x2TB Caviar Black in RAID4?

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  • How to define template directives (from an API perspective)?

    - by Ralph
    Preface I'm writing a template language (don't bother trying to talk me out of it), and in it, there are two kinds of user-extensible nodes. TemplateTags and TemplateDirectives. A TemplateTag closely relates to an HTML tag -- it might look something like div(class="green") { "content" } And it'll be rendered as <div class="green">content</div> i.e., it takes a bunch of attributes, plus some content, and spits out some HTML. TemplateDirectives are a little more complicated. They can be things like for loops, ifs, includes, and other such things. They look a lot like a TemplateTag, but they need to be processed differently. For example, @for($i in $items) { div(class="green") { $i } } Would loop over $items and output the content with the variable $i substituted in each time. So.... I'm trying to decide on a way to define these directives now. Template Tags The TemplateTags are pretty easy to write. They look something like this: [TemplateTag] static string div(string content = null, object attrs = null) { return HtmlTag("div", content, attrs); } Where content gets the stuff between the curly braces (pre-rendered if there are variables in it and such), and attrs is either a Dictionary<string,object> of attributes, or an anonymous type used like a dictionary. It just returns the HTML which gets plunked into its place. Simple! You can write tags in basically 1 line. Template Directives The way I've defined them now looks like this: [TemplateDirective] static string @for(string @params, string content) { var tokens = Regex.Split(@params, @"\sin\s").Select(s => s.Trim()).ToArray(); string itemName = tokens[0].Substring(1); string enumName = tokens[1].Substring(1); var enumerable = data[enumName] as IEnumerable; var sb = new StringBuilder(); var template = new Template(content); foreach (var item in enumerable) { var templateVars = new Dictionary<string, object>(data) { { itemName, item } }; sb.Append(template.Render(templateVars)); } return sb.ToString(); } (Working example). Basically, the stuff between the ( and ) is not split into arguments automatically (like the template tags do), and the content isn't pre-rendered either. The reason it isn't pre-rendered is because you might want to add or remove some template variables or something first. In this case, we add the $i variable to the template variables, var templateVars = new Dictionary<string, object>(data) { { itemName, item } }; And then render the content manually, sb.Append(template.Render(templateVars)); Question I'm wondering if this is the best approach to defining custom Template Directives. I want to make it as easy as possible. What if the user doesn't know how to render templates, or doesn't know that he's supposed to? Maybe I should pass in a Template instance pre-filled with the content instead? Or maybe only let him tamper w/ the template variables, and then automatically render the content at the end? OTOH, for things like "if" if the condition fails, then the template wouldn't need to be rendered at all. So there's a lot of flexibility I need to allow in here. Thoughts?

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  • drupal - override form action?

    - by n00b0101
    I originally started this question in another thread, but that thread was sorta, kinda answered, and now I primarily want to know how to specify another form action... I tried using the code below, but the form action, when output, remains unchanged, although looking at the print_r($form), it's correctly changed... Why isn't it picking up? function mytheme_user_profile_form($form) { global $user; $uid = $user->uid; //print '<pre>'; print_r($form); print '</pre>'; $category = $form['_category']['#value']; switch($category) { case 'account': $form['#action'] = '/user/'.$uid.'/edit?destination=user/'.$uid; break; case 'education': $form['#action'] = '/user/'.$uid.'/edit/education?destination=user/'.$uid; break; case 'experience': $form['#action'] = '/user/'.$uid.'/edit/experience?destination=user/'.$uid; break; case 'publications': $form['#action'] = '/user/'.$uid.'/edit/publications?destination=user/'.$uid; break; case 'conflicts': $form['#action'] = '/user/'.$uid.'/edit/conflicts?destination=user/'.$uid; break; } //print '<pre>'; print_r($form); print '</pre>'; //print $form['#action']; $output .= drupal_render($form); return $output;

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  • Determine between files and folders using cURL

    - by ILMV
    I'm writing a script to download files from an FTP server using cURL + PHP, at the moment I am just trying to build a complete file structure, here's the code I'm using so far: <?php $curl = curl_init(); curl_setopt($curl, CURLOPT_URL, "ftp://www.example.com"); curl_setopt($curl, CURLOPT_USERPWD, "user:pwd"); curl_setopt ($curl, CURLOPT_RETURNTRANSFER, 1) ; curl_setopt($curl, CURLOPT_CUSTOMREQUEST, 'NLST'); // or curl_setopt($curl, CURLOPT_CUSTOMREQUEST, 'LIST -a'); $ftp=curl_exec($curl); $directory=split("[\n|\r]",$ftp); echo("<pre>".print_r($directory,true)."</pre>"); foreach($directory as $key=>$value) if($value=='') unset($directory[$key]); echo("<pre>".print_r($directory,true)."</pre>"); curl_close ($curl); ?> I can use either NLST or the LIST function, but what I want to do is programatically determine what are files and what are folders. Thanks!

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  • How to Manage project in this scenario

    - by vijay.shad
    Hi All, I am working on a web application which has got good amount of static or pre-login pages. These pages can have some simple forms as well where we would like to capture the visitor's details. Post login, I have got my main application. I am confused about the development and deployment architecture of my application. Post login part of my application has a release cycle of 1-2 months while pre-login pages are to be updated on a weekly basis. It is difficult to make a release of pre-login pages as the overall war also contains post-login application & which sometimes is not release ready. Currently, I have got both these parts bundled in the single war project. Please help me by letting me know the best practices whereby I can achieve following: Manage the releases of these two parts independently. I am using Maven. So is there a way I can share the resources, such as CSS, images etc between these two parts. Header and footer of my application is going to be same on pre-login & post-login pages. I was thinking of deploying these apps as two war files in my tomcat container. But then how will I manage the common resources like Css, images etc. Rgds Vijay

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  • Iframe form not submittin in IE but working in Firefox

    - by Younes
    I have got a form that posts values to a page in a wizard. When i'm loading this form in a Iframe everything is working fine in Firefox, it will get me to the second step of the wizard and maintains the values i filled in. When im testing this in Internet Explorer i am not getting to the second step, instead of that it returns me to the first step of the wizard with all fields being blank. When i check this in Fiddler i see that im getting a different response when i'm posting the form in the Iframe from Firefox compared to Internet Explorer. How can i make this work for all browsers? What am I doing wrong? This is what i get back from Fiddler: Firefox Post: Ressult Protocol Host URL Body Caching Content-Type Process Comments Custom 1 302 HTTP www.dmg.eu /brugman/budgetplanner/aanmelden.php 0 no-store, no-cache, must-revalidate, post-check=0, pre-check=0 Expires: Thu, 19 Nov 1981 08:52:00 GMT text/html; charset=UTF-8 firefox:6116 Get: # Result Protocol Host URL Body Caching Content-Type Process Comments Custom 2 200 HTTP www.dmg.eu /brugman/budgetplanner/ 40.677 no-store, no-cache, must-revalidate, post-check=0, pre-check=0 Expires: Thu, 19 Nov 1981 08:52:00 GMT text/html; charset=UTF-8 firefox:6116 Internet Explorer Post: Result Protocol Host URL Body Caching Content-Type Process Comments Custom 73 302 HTTP www.dmg.eu /brugman/budgetplanner/aanmelden.php 0 no-store, no-cache, must-revalidate, post-check=0, pre-check=0 Expires: Thu, 19 Nov 1981 08:52:00 GMT text/html; charset=UTF-8 iexplore:536 Get: Result Protocol Host URL Body Caching Content-Type Process Comments Custom 74 302 HTTP www.dmg.eu /brugman/budgetplanner/ 0 no-store, no-cache, must-revalidate, post-check=0, pre-check=0 Expires: Thu, 19 Nov 1981 08:52:00 GMT text/html; charset=UTF-8 iexplore:536 Hope someone knows what the diff is :).

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  • How to mix Grammar (Rules) & Dictation (Free speech) with SpeechRecognizer in C#

    - by Lee Englestone
    I really like Microsofts latest speech recognition (and SpeechSynthesis) offerings. http://msdn.microsoft.com/en-us/library/ms554855.aspx http://estellasays.blogspot.com/2009/04/speech-recognition-in-cnet.html However I feel like I'm somewhat limited when using grammars. Don't get me wrong grammars are great for telling the speech recognition exactly what words / phrases to look out for, however what if I want it to recognise something i've not given it a heads up about? Or I want to parse a phrase which is half pre-determined command name and half random words? For example.. Scenario A - I say "Google [Oil Spill]" and I want it to open Google with search results for the term in brackets which could be anything. Scenario B - I say "Locate [Manchester]" and I want it to search for Manchester in Google Maps or anything else non pre-determined I want it to know that 'Google' and 'Locate' are commands and what comes after it are parameters (and could be anything). Question : Does anyone know how to mix the use of pre-determined grammars (words the speech recognition should recognise) and words not in its pre-determined grammar? Code fragments.. using System.Speech.Recognition; ... ... SpeechRecognizer rec = new SpeechRecognizer(); rec.SpeechRecognized += rec_SpeechRecognized; var c = new Choices(); c.Add("search"); var gb = new GrammarBuilder(c); var g = new Grammar(gb); rec.LoadGrammar(g); rec.Enabled = true; ... ... void rec_SpeechRecognized(object sender, SpeechRecognizedEventArgs e) { if (e.Result.Text == "search") { string query = "How can I get a word not defined in Grammar recognised and passed into here!"; launchGoogle(query); } } ... ... private void launchGoogle(string term) { Process.Start("IEXPLORE", "google.com?q=" + term); }

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  • How do you convert a parent-child (adjacency) table to a nested set using PHP and MySQL?

    - by mrbinky3000
    I've spent the last few hours trying to find the solution to this question online. I've found plenty of examples on how to convert from nested set to adjacency... but few that go the other way around. The examples I have found either don't work or use MySQL procedures. Unfortunately, I can't use procedures for this project. I need a pure PHP solution. I have a table that uses the adjacency model below: id parent_id category 1 0 ROOT_NODE 2 1 Books 3 1 CD's 4 1 Magazines 5 2 Books/Hardcover 6 2 Books/Large Format 7 4 Magazines/Vintage And I would like to convert it to a Nested Set table below: id left right category 1 1 14 Root Node 2 2 7 Books 3 3 4 Books/Hardcover 4 5 6 Books/Large Format 5 8 9 CD's 6 10 13 Magazines 7 11 12 Magazines/Vintage Here is an image of what I need: I have a function, based on the pseudo code from this forum post (http://www.sitepoint.com/forums/showthread.php?t=320444) but it doesn't work. I get multiple rows that have the same value for left. This should not happen. <?php /** -- -- Table structure for table `adjacent_table` -- CREATE TABLE IF NOT EXISTS `adjacent_table` ( `id` int(11) NOT NULL AUTO_INCREMENT, `father_id` int(11) DEFAULT NULL, `category` varchar(128) DEFAULT NULL, PRIMARY KEY (`id`) ) ENGINE=MyISAM DEFAULT CHARSET=latin1 AUTO_INCREMENT=8 ; -- -- Dumping data for table `adjacent_table` -- INSERT INTO `adjacent_table` (`id`, `father_id`, `category`) VALUES (1, 0, 'ROOT'), (2, 1, 'Books'), (3, 1, 'CD''s'), (4, 1, 'Magazines'), (5, 2, 'Hard Cover'), (6, 2, 'Large Format'), (7, 4, 'Vintage'); -- -- Table structure for table `nested_table` -- CREATE TABLE IF NOT EXISTS `nested_table` ( `id` int(11) NOT NULL AUTO_INCREMENT, `lft` int(11) DEFAULT NULL, `rgt` int(11) DEFAULT NULL, `category` varchar(128) DEFAULT NULL, PRIMARY KEY (`id`) ) ENGINE=MyISAM DEFAULT CHARSET=latin1 AUTO_INCREMENT=1 ; */ mysql_connect('localhost','USER','PASSWORD') or die(mysql_error()); mysql_select_db('DATABASE') or die(mysql_error()); adjacent_to_nested(0); /** * adjacent_to_nested * * Reads a "adjacent model" table and converts it to a "Nested Set" table. * @param integer $i_id Should be the id of the "root node" in the adjacent table; * @param integer $i_left Should only be used on recursive calls. Holds the current value for lft */ function adjacent_to_nested($i_id, $i_left = 0) { // the right value of this node is the left value + 1 $i_right = $i_left + 1; // get all children of this node $a_children = get_source_children($i_id); foreach ($a_children as $a) { // recursive execution of this function for each child of this node // $i_right is the current right value, which is incremented by the // import_from_dc_link_category method $i_right = adjacent_to_nested($a['id'], $i_right); // insert stuff into the our new "Nested Sets" table $s_query = " INSERT INTO `nested_table` (`id`, `lft`, `rgt`, `category`) VALUES( NULL, '".$i_left."', '".$i_right."', '".mysql_real_escape_string($a['category'])."' ) "; if (!mysql_query($s_query)) { echo "<pre>$s_query</pre>\n"; throw new Exception(mysql_error()); } echo "<p>$s_query</p>\n"; // get the newly created row id $i_new_nested_id = mysql_insert_id(); } return $i_right + 1; } /** * get_source_children * * Examines the "adjacent" table and finds all the immediate children of a node * @param integer $i_id The unique id for a node in the adjacent_table table * @return array Returns an array of results or an empty array if no results. */ function get_source_children($i_id) { $a_return = array(); $s_query = "SELECT * FROM `adjacent_table` WHERE `father_id` = '".$i_id."'"; if (!$i_result = mysql_query($s_query)) { echo "<pre>$s_query</pre>\n"; throw new Exception(mysql_error()); } if (mysql_num_rows($i_result) > 0) { while($a = mysql_fetch_assoc($i_result)) { $a_return[] = $a; } } return $a_return; } ?> This is the output of the above script. INSERT INTO nested_table (id, lft, rgt, category) VALUES( NULL, '2', '5', 'Hard Cover' ) INSERT INTO nested_table (id, lft, rgt, category) VALUES( NULL, '2', '7', 'Large Format' ) INSERT INTO nested_table (id, lft, rgt, category) VALUES( NULL, '1', '8', 'Books' ) INSERT INTO nested_table (id, lft, rgt, category) VALUES( NULL, '1', '10', 'CD\'s' ) INSERT INTO nested_table (id, lft, rgt, category) VALUES( NULL, '10', '13', 'Vintage' ) INSERT INTO nested_table (id, lft, rgt, category) VALUES( NULL, '1', '14', 'Magazines' ) INSERT INTO nested_table (id, lft, rgt, category) VALUES( NULL, '0', '15', 'ROOT' ) As you can see, there are multiple rows sharing the lft value of "1" same goes for "2" In a nested-set, the values for left and right must be unique. Here is an example of how to manually number the left and right ID's in a nested set: UPDATE - PROBLEM SOLVED First off, I had mistakenly believed that the source table (the one in adjacent-lists format) needed to be altered to include a source node. This is not the case. Secondly, I found a cached page on BING (of all places) with a class that does the trick. I've altered it for PHP5 and converted the original author's mysql related bits to basic PHP. He was using some DB class. You can convert them to your own database abstraction class later if you want. Obviously, if your "source table" has other columns that you want to move to the nested set table, you will have to adjust the write method in the class below. Hopefully this will save someone else from the same problems in the future. <?php /** -- -- Table structure for table `adjacent_table` -- DROP TABLE IF EXISTS `adjacent_table`; CREATE TABLE IF NOT EXISTS `adjacent_table` ( `id` int(11) NOT NULL AUTO_INCREMENT, `father_id` int(11) DEFAULT NULL, `category` varchar(128) DEFAULT NULL, PRIMARY KEY (`id`) ) ENGINE=MyISAM DEFAULT CHARSET=latin1 AUTO_INCREMENT=8 ; -- -- Dumping data for table `adjacent_table` -- INSERT INTO `adjacent_table` (`id`, `father_id`, `category`) VALUES (1, 0, 'Books'), (2, 0, 'CD''s'), (3, 0, 'Magazines'), (4, 1, 'Hard Cover'), (5, 1, 'Large Format'), (6, 3, 'Vintage'); -- -- Table structure for table `nested_table` -- DROP TABLE IF EXISTS `nested_table`; CREATE TABLE IF NOT EXISTS `nested_table` ( `lft` int(11) NOT NULL DEFAULT '0', `rgt` int(11) DEFAULT NULL, `id` int(11) DEFAULT NULL, `category` varchar(128) DEFAULT NULL, PRIMARY KEY (`lft`), UNIQUE KEY `id` (`id`), UNIQUE KEY `rgt` (`rgt`) ) ENGINE=MyISAM DEFAULT CHARSET=latin1; */ /** * @class tree_transformer * @author Paul Houle, Matthew Toledo * @created 2008-11-04 * @url http://gen5.info/q/2008/11/04/nested-sets-php-verb-objects-and-noun-objects/ */ class tree_transformer { private $i_count; private $a_link; public function __construct($a_link) { if(!is_array($a_link)) throw new Exception("First parameter should be an array. Instead, it was type '".gettype($a_link)."'"); $this->i_count = 1; $this->a_link= $a_link; } public function traverse($i_id) { $i_lft = $this->i_count; $this->i_count++; $a_kid = $this->get_children($i_id); if ($a_kid) { foreach($a_kid as $a_child) { $this->traverse($a_child); } } $i_rgt=$this->i_count; $this->i_count++; $this->write($i_lft,$i_rgt,$i_id); } private function get_children($i_id) { return $this->a_link[$i_id]; } private function write($i_lft,$i_rgt,$i_id) { // fetch the source column $s_query = "SELECT * FROM `adjacent_table` WHERE `id` = '".$i_id."'"; if (!$i_result = mysql_query($s_query)) { echo "<pre>$s_query</pre>\n"; throw new Exception(mysql_error()); } $a_source = array(); if (mysql_num_rows($i_result)) { $a_source = mysql_fetch_assoc($i_result); } // root node? label it unless already labeled in source table if (1 == $i_lft && empty($a_source['category'])) { $a_source['category'] = 'ROOT'; } // insert into the new nested tree table // use mysql_real_escape_string because one value "CD's" has a single ' $s_query = " INSERT INTO `nested_table` (`id`,`lft`,`rgt`,`category`) VALUES ( '".$i_id."', '".$i_lft."', '".$i_rgt."', '".mysql_real_escape_string($a_source['category'])."' ) "; if (!$i_result = mysql_query($s_query)) { echo "<pre>$s_query</pre>\n"; throw new Exception(mysql_error()); } else { // success: provide feedback echo "<p>$s_query</p>\n"; } } } mysql_connect('localhost','USER','PASSWORD') or die(mysql_error()); mysql_select_db('DATABASE') or die(mysql_error()); // build a complete copy of the adjacency table in ram $s_query = "SELECT `id`,`father_id` FROM `adjacent_table`"; $i_result = mysql_query($s_query); $a_rows = array(); while ($a_rows[] = mysql_fetch_assoc($i_result)); $a_link = array(); foreach($a_rows as $a_row) { $i_father_id = $a_row['father_id']; $i_child_id = $a_row['id']; if (!array_key_exists($i_father_id,$a_link)) { $a_link[$i_father_id]=array(); } $a_link[$i_father_id][]=$i_child_id; } $o_tree_transformer = new tree_transformer($a_link); $o_tree_transformer->traverse(0); ?>

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  • How does this RegEx for parsing emails work in PHP?

    - by George Edison
    Okay, I have the following PHP code to extract an email address of the following two forms: Random Stranger <[email protected]> [email protected] Here is the PHP code: // The first example $sender = "Random Stranger <[email protected]>"; $pattern = '/([\w_-]*@[\w-\.]*)|.*<([\w_-]*@[\w-\.]*)>/'; preg_match($pattern,$sender,$matches,PREG_OFFSET_CAPTURE); echo "<pre>"; print_r($matches); echo "</pre><hr>"; // The second example $sender = "[email protected]"; preg_match($pattern,$sender,$matches,PREG_OFFSET_CAPTURE); echo "<pre>"; print_r($matches); echo "</pre>"; My question is... what is in $matches? It seems to be a strange collection of arrays. Which index holds the match from the parenthesis? How can I be sure I'm getting the email address and only the email address? Update: Here is the output: Array ( [0] => Array ( [0] => Random Stranger [1] => 0 ) [1] => Array ( [0] => [1] => -1 ) [2] => Array ( [0] => [email protected] [1] => 5 ) ) Array ( [0] => Array ( [0] => [email protected] [1] => 0 ) [1] => Array ( [0] => [email protected] [1] => 0 ) )

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  • How to mix Grammer (Rules) & Dictation (Free speech) with SpeechRecognizer in C#

    - by Lee Englestone
    I really like Microsofts latest speech recognition (and SpeechSynthesis) offerings. http://msdn.microsoft.com/en-us/library/ms554855.aspx http://estellasays.blogspot.com/2009/04/speech-recognition-in-cnet.html However I feel like I'm somewhat limited when using grammers. Don't get me wrong grammers are great for telling the speech recognition exactly what words / phrases to look out for, however what if I want it to recognise something i've not given it a heads up about? Or I want to parse a phrase which is half pre-determined command name and half random words? For example.. Scenario A - I say "Google [Oil Spill]" and I want it to open Google with search results for the term in brackets which could be anything. Scenario B - I say "Locate [Manchester]" and I want it to search for Manchester in Google Maps or anything else non pre-determined I want it to know that 'Google' and 'Locate' are commands and what comes after it are parameters (and could be anything). Question : Does anyone know how to mix the use of pre-determined grammers (words the speech recognition should recognise) and words not in its pre-determined grammer? Code fragments.. using System.Speech.Recognition; ... ... SpeechRecognizer rec = new SpeechRecognizer(); rec.SpeechRecognized += rec_SpeechRecognized; var c = new Choices(); c.Add("search"); var gb = new GrammarBuilder(c); var g = new Grammar(gb); rec.LoadGrammar(g); rec.Enabled = true; ... ... void rec_SpeechRecognized(object sender, SpeechRecognizedEventArgs e) { if (e.Result.Text == "search") { string query = "How can I get a word not defined in Grammer recognised and passed into here!"; launchGoogle(query); } } ... ... private void launchGoogle(string term) { Process.Start("IEXPLORE", "google.com?q=" + term); }

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  • problem with the table width in IE?

    - by Harish Kurup
    I am using table to display a set of data, my HTML code goes here... <table border="1" cellspacing="0" cellpadding="0" style="width: 780px;"> <tbody> <tr> <td style="width: 780px; height: 25px;"> <pre width='100' style='width: 780px; word-wrap: break-word;'> the data goes here..... </pre> </td> </tr> <tr> <td style="width: 780px; height: 25px;"> <pre width='100' style='width: 780px; word-wrap: break-word;'> the data goes here..... </pre> </td> </tr> </tbody> </table> this table works ok in firefox, safari, and IE8. But the problem arise in IE7, IE6.. asthe table expands and goes out of the screen(i.e expands towards right hand side in x-axis).... is there any hack to fix it?

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  • Differences Between NHibernate and Entity Framework

    - by Ricardo Peres
    Introduction NHibernate and Entity Framework are two of the most popular O/RM frameworks on the .NET world. Although they share some functionality, there are some aspects on which they are quite different. This post will describe this differences and will hopefully help you get started with the one you know less. Mind you, this is a personal selection of features to compare, it is by no way an exhaustive list. History First, a bit of history. NHibernate is an open-source project that was first ported from Java’s venerable Hibernate framework, one of the first O/RM frameworks, but nowadays it is not tied to it, for example, it has .NET specific features, and has evolved in different ways from those of its Java counterpart. Current version is 3.3, with 3.4 on the horizon. It currently targets .NET 3.5, but can be used as well in .NET 4, it only makes no use of any of its specific functionality. You can find its home page at NHForge. Entity Framework 1 came out with .NET 3.5 and is now on its second major version, despite being version 4. Code First sits on top of it and but came separately and will also continue to be released out of line with major .NET distributions. It is currently on version 4.3.1 and version 5 will be released together with .NET Framework 4.5. All versions will target the current version of .NET, at the time of their release. Its home location is located at MSDN. Architecture In NHibernate, there is a separation between the Unit of Work and the configuration and model instances. You start off by creating a Configuration object, where you specify all global NHibernate settings such as the database and dialect to use, the batch sizes, the mappings, etc, then you build an ISessionFactory from it. The ISessionFactory holds model and metadata that is tied to a particular database and to the settings that came from the Configuration object, and, there will typically be only one instance of each in a process. Finally, you create instances of ISession from the ISessionFactory, which is the NHibernate representation of the Unit of Work and Identity Map. This is a lightweight object, it basically opens and closes a database connection as required and keeps track of the entities associated with it. ISession objects are cheap to create and dispose, because all of the model complexity is stored in the ISessionFactory and Configuration objects. As for Entity Framework, the ObjectContext/DbContext holds the configuration, model and acts as the Unit of Work, holding references to all of the known entity instances. This class is therefore not lightweight as its NHibernate counterpart and it is not uncommon to see examples where an instance is cached on a field. Mappings Both NHibernate and Entity Framework (Code First) support the use of POCOs to represent entities, no base classes are required (or even possible, in the case of NHibernate). As for mapping to and from the database, NHibernate supports three types of mappings: XML-based, which have the advantage of not tying the entity classes to a particular O/RM; the XML files can be deployed as files on the file system or as embedded resources in an assembly; Attribute-based, for keeping both the entities and database details on the same place at the expense of polluting the entity classes with NHibernate-specific attributes; Strongly-typed code-based, which allows dynamic creation of the model and strongly typing it, so that if, for example, a property name changes, the mapping will also be updated. Entity Framework can use: Attribute-based (although attributes cannot express all of the available possibilities – for example, cascading); Strongly-typed code mappings. Database Support With NHibernate you can use mostly any database you want, including: SQL Server; SQL Server Compact; SQL Server Azure; Oracle; DB2; PostgreSQL; MySQL; Sybase Adaptive Server/SQL Anywhere; Firebird; SQLLite; Informix; Any through OLE DB; Any through ODBC. Out of the box, Entity Framework only supports SQL Server, but a number of providers exist, both free and commercial, for some of the most used databases, such as Oracle and MySQL. See a list here. Inheritance Strategies Both NHibernate and Entity Framework support the three canonical inheritance strategies: Table Per Type Hierarchy (Single Table Inheritance), Table Per Type (Class Table Inheritance) and Table Per Concrete Type (Concrete Table Inheritance). Associations Regarding associations, both support one to one, one to many and many to many. However, NHibernate offers far more collection types: Bags of entities or values: unordered, possibly with duplicates; Lists of entities or values: ordered, indexed by a number column; Maps of entities or values: indexed by either an entity or any value; Sets of entities or values: unordered, no duplicates; Arrays of entities or values: indexed, immutable. Querying NHibernate exposes several querying APIs: LINQ is probably the most used nowadays, and really does not need to be introduced; Hibernate Query Language (HQL) is a database-agnostic, object-oriented SQL-alike language that exists since NHibernate’s creation and still offers the most advanced querying possibilities; well suited for dynamic queries, even if using string concatenation; Criteria API is an implementation of the Query Object pattern where you create a semi-abstract conceptual representation of the query you wish to execute by means of a class model; also a good choice for dynamic querying; Query Over offers a similar API to Criteria, but using strongly-typed LINQ expressions instead of strings; for this, although more refactor-friendlier that Criteria, it is also less suited for dynamic queries; SQL, including stored procedures, can also be used; Integration with Lucene.NET indexer is available. As for Entity Framework: LINQ to Entities is fully supported, and its implementation is considered very complete; it is the API of choice for most developers; Entity-SQL, HQL’s counterpart, is also an object-oriented, database-independent querying language that can be used for dynamic queries; SQL, of course, is also supported. Caching Both NHibernate and Entity Framework, of course, feature first-level cache. NHibernate also supports a second-level cache, that can be used among multiple ISessionFactorys, even in different processes/machines: Hashtable (in-memory); SysCache (uses ASP.NET as the cache provider); SysCache2 (same as above but with support for SQL Server SQL Dependencies); Prevalence; SharedCache; Memcached; Redis; NCache; Appfabric Caching. Out of the box, Entity Framework does not have any second-level cache mechanism, however, there are some public samples that show how we can add this. ID Generators NHibernate supports different ID generation strategies, coming from the database and otherwise: Identity (for SQL Server, MySQL, and databases who support identity columns); Sequence (for Oracle, PostgreSQL, and others who support sequences); Trigger-based; HiLo; Sequence HiLo (for databases that support sequences); Several GUID flavors, both in GUID as well as in string format; Increment (for single-user uses); Assigned (must know what you’re doing); Sequence-style (either uses an actual sequence or a single-column table); Table of ids; Pooled (similar to HiLo but stores high values in a table); Native (uses whatever mechanism the current database supports, identity or sequence). Entity Framework only supports: Identity generation; GUIDs; Assigned values. Properties NHibernate supports properties of entity types (one to one or many to one), collections (one to many or many to many) as well as scalars and enumerations. It offers a mechanism for having complex property types generated from the database, which even include support for querying. It also supports properties originated from SQL formulas. Entity Framework only supports scalars, entity types and collections. Enumerations support will come in the next version. Events and Interception NHibernate has a very rich event model, that exposes more than 20 events, either for synchronous pre-execution or asynchronous post-execution, including: Pre/Post-Load; Pre/Post-Delete; Pre/Post-Insert; Pre/Post-Update; Pre/Post-Flush. It also features interception of class instancing and SQL generation. As for Entity Framework, only two events exist: ObjectMaterialized (after loading an entity from the database); SavingChanges (before saving changes, which include deleting, inserting and updating). Tracking Changes For NHibernate as well as Entity Framework, all changes are tracked by their respective Unit of Work implementation. Entities can be attached and detached to it, Entity Framework does, however, also support self-tracking entities. Optimistic Concurrency Control NHibernate supports all of the imaginable scenarios: SQL Server’s ROWVERSION; Oracle’s ORA_ROWSCN; A column containing date and time; A column containing a version number; All/dirty columns comparison. Entity Framework is more focused on Entity Framework, so it only supports: SQL Server’s ROWVERSION; Comparing all/some columns. Batching NHibernate has full support for insertion batching, but only if the ID generator in use is not database-based (for example, it cannot be used with Identity), whereas Entity Framework has no batching at all. Cascading Both support cascading for collections and associations: when an entity is deleted, their conceptual children are also deleted. NHibernate also offers the possibility to set the foreign key column on children to NULL instead of removing them. Flushing Changes NHibernate’s ISession has a FlushMode property that can have the following values: Auto: changes are sent to the database when necessary, for example, if there are dirty instances of an entity type, and a query is performed against this entity type, or if the ISession is being disposed; Commit: changes are sent when committing the current transaction; Never: changes are only sent when explicitly calling Flush(). As for Entity Framework, changes have to be explicitly sent through a call to AcceptAllChanges()/SaveChanges(). Lazy Loading NHibernate supports lazy loading for Associated entities (one to one, many to one); Collections (one to many, many to many); Scalar properties (thing of BLOBs or CLOBs). Entity Framework only supports lazy loading for: Associated entities; Collections. Generating and Updating the Database Both NHibernate and Entity Framework Code First (with the Migrations API) allow creating the database model from the mapping and updating it if the mapping changes. Extensibility As you can guess, NHibernate is far more extensible than Entity Framework. Basically, everything can be extended, from ID generation, to LINQ to SQL transformation, HQL native SQL support, custom column types, custom association collections, SQL generation, supported databases, etc. With Entity Framework your options are more limited, at least, because practically no information exists as to what can be extended/changed. It features a provider model that can be extended to support any database. Integration With Other Microsoft APIs and Tools When it comes to integration with Microsoft technologies, it will come as no surprise that Entity Framework offers the best support. For example, the following technologies are fully supported: ASP.NET (through the EntityDataSource); ASP.NET Dynamic Data; WCF Data Services; WCF RIA Services; Visual Studio (through the integrated designer). Documentation This is another point where Entity Framework is superior: NHibernate lacks, for starters, an up to date API reference synchronized with its current version. It does have a community mailing list, blogs and wikis, although not much used. Entity Framework has a number of resources on MSDN and, of course, several forums and discussion groups exist. Conclusion Like I said, this is a personal list. I may come as a surprise to some that Entity Framework is so behind NHibernate in so many aspects, but it is true that NHibernate is much older and, due to its open-source nature, is not tied to product-specific timeframes and can thus evolve much more rapidly. I do like both, and I chose whichever is best for the job I have at hands. I am looking forward to the changes in EF5 which will add significant value to an already interesting product. So, what do you think? Did I forget anything important or is there anything else worth talking about? Looking forward for your comments!

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  • ASP.NET and HTML5 Local Storage

    - by Stephen Walther
    My favorite feature of HTML5, hands-down, is HTML5 local storage (aka DOM storage). By taking advantage of HTML5 local storage, you can dramatically improve the performance of your data-driven ASP.NET applications by caching data in the browser persistently. Think of HTML5 local storage like browser cookies, but much better. Like cookies, local storage is persistent. When you add something to browser local storage, it remains there when the user returns to the website (possibly days or months later). Importantly, unlike the cookie storage limitation of 4KB, you can store up to 10 megabytes in HTML5 local storage. Because HTML5 local storage works with the latest versions of all modern browsers (IE, Firefox, Chrome, Safari), you can start taking advantage of this HTML5 feature in your applications right now. Why use HTML5 Local Storage? I use HTML5 Local Storage in the JavaScript Reference application: http://Superexpert.com/JavaScriptReference The JavaScript Reference application is an HTML5 app that provides an interactive reference for all of the syntax elements of JavaScript (You can read more about the application and download the source code for the application here). When you open the application for the first time, all of the entries are transferred from the server to the browser (all 300+ entries). All of the entries are stored in local storage. When you open the application in the future, only changes are transferred from the server to the browser. The benefit of this approach is that the application performs extremely fast. When you click the details link to view details on a particular entry, the entry details appear instantly because all of the entries are stored on the client machine. When you perform key-up searches, by typing in the filter textbox, matching entries are displayed very quickly because the entries are being filtered on the local machine. This approach can have a dramatic effect on the performance of any interactive data-driven web application. Interacting with data on the client is almost always faster than interacting with the same data on the server. Retrieving Data from the Server In the JavaScript Reference application, I use Microsoft WCF Data Services to expose data to the browser. WCF Data Services generates a REST interface for your data automatically. Here are the steps: Create your database tables in Microsoft SQL Server. For example, I created a database named ReferenceDB and a database table named Entities. Use the Entity Framework to generate your data model. For example, I used the Entity Framework to generate a class named ReferenceDBEntities and a class named Entities. Expose your data through WCF Data Services. I added a WCF Data Service to my project and modified the data service class to look like this:   using System.Data.Services; using System.Data.Services.Common; using System.Web; using JavaScriptReference.Models; namespace JavaScriptReference.Services { [System.ServiceModel.ServiceBehavior(IncludeExceptionDetailInFaults = true)] public class EntryService : DataService<ReferenceDBEntities> { // This method is called only once to initialize service-wide policies. public static void InitializeService(DataServiceConfiguration config) { config.UseVerboseErrors = true; config.SetEntitySetAccessRule("*", EntitySetRights.All); config.DataServiceBehavior.MaxProtocolVersion = DataServiceProtocolVersion.V2; } // Define a change interceptor for the Products entity set. [ChangeInterceptor("Entries")] public void OnChangeEntries(Entry entry, UpdateOperations operations) { if (!HttpContext.Current.Request.IsAuthenticated) { throw new DataServiceException("Cannot update reference unless authenticated."); } } } }     The WCF data service is named EntryService. Notice that it derives from DataService<ReferenceEntitites>. Because it derives from DataService<ReferenceEntities>, the data service exposes the contents of the ReferenceEntitiesDB database. In the code above, I defined a ChangeInterceptor to prevent un-authenticated users from making changes to the database. Anyone can retrieve data through the service, but only authenticated users are allowed to make changes. After you expose data through a WCF Data Service, you can use jQuery to retrieve the data by performing an Ajax call. For example, I am using an Ajax call that looks something like this to retrieve the JavaScript entries from the EntryService.svc data service: $.ajax({ dataType: "json", url: “/Services/EntryService.svc/Entries”, success: function (result) { var data = callback(result["d"]); } });     Notice that you must unwrap the data using result[“d”]. After you unwrap the data, you have a JavaScript array of the entries. I’m transferring all 300+ entries from the server to the client when the application is opened for the first time. In other words, I transfer the entire database from the server to the client, once and only once, when the application is opened for the first time. The data is transferred using JSON. Here is a fragment: { "d" : [ { "__metadata": { "uri": "http://superexpert.com/javascriptreference/Services/EntryService.svc/Entries(1)", "type": "ReferenceDBModel.Entry" }, "Id": 1, "Name": "Global", "Browsers": "ff3_6,ie8,ie9,c8,sf5,es3,es5", "Syntax": "object", "ShortDescription": "Contains global variables and functions", "FullDescription": "<p>\nThe Global object is determined by the host environment. In web browsers, the Global object is the same as the windows object.\n</p>\n<p>\nYou can use the keyword <code>this</code> to refer to the Global object when in the global context (outside of any function).\n</p>\n<p>\nThe Global object holds all global variables and functions. For example, the following code demonstrates that the global <code>movieTitle</code> variable refers to the same thing as <code>window.movieTitle</code> and <code>this.movieTitle</code>.\n</p>\n<pre>\nvar movieTitle = \"Star Wars\";\nconsole.log(movieTitle === this.movieTitle); // true\nconsole.log(movieTitle === window.movieTitle); // true\n</pre>\n", "LastUpdated": "634298578273756641", "IsDeleted": false, "OwnerId": null }, { "__metadata": { "uri": "http://superexpert.com/javascriptreference/Services/EntryService.svc/Entries(2)", "type": "ReferenceDBModel.Entry" }, "Id": 2, "Name": "eval(string)", "Browsers": "ff3_6,ie8,ie9,c8,sf5,es3,es5", "Syntax": "function", "ShortDescription": "Evaluates and executes JavaScript code dynamically", "FullDescription": "<p>\nThe following code evaluates and executes the string \"3+5\" at runtime.\n</p>\n<pre>\nvar result = eval(\"3+5\");\nconsole.log(result); // returns 8\n</pre>\n<p>\nYou can rewrite the code above like this:\n</p>\n<pre>\nvar result;\neval(\"result = 3+5\");\nconsole.log(result);\n</pre>", "LastUpdated": "634298580913817644", "IsDeleted": false, "OwnerId": 1 } … ]} I worried about the amount of time that it would take to transfer the records. According to Google Chome, it takes about 5 seconds to retrieve all 300+ records on a broadband connection over the Internet. 5 seconds is a small price to pay to avoid performing any server fetches of the data in the future. And here are the estimated times using different types of connections using Fiddler: Notice that using a modem, it takes 33 seconds to download the database. 33 seconds is a significant chunk of time. So, I would not use the approach of transferring the entire database up front if you expect a significant portion of your website audience to connect to your website with a modem. Adding Data to HTML5 Local Storage After the JavaScript entries are retrieved from the server, the entries are stored in HTML5 local storage. Here’s the reference documentation for HTML5 storage for Internet Explorer: http://msdn.microsoft.com/en-us/library/cc197062(VS.85).aspx You access local storage by accessing the windows.localStorage object in JavaScript. This object contains key/value pairs. For example, you can use the following JavaScript code to add a new item to local storage: <script type="text/javascript"> window.localStorage.setItem("message", "Hello World!"); </script>   You can use the Google Chrome Storage tab in the Developer Tools (hit CTRL-SHIFT I in Chrome) to view items added to local storage: After you add an item to local storage, you can read it at any time in the future by using the window.localStorage.getItem() method: <script type="text/javascript"> window.localStorage.setItem("message", "Hello World!"); </script>   You only can add strings to local storage and not JavaScript objects such as arrays. Therefore, before adding a JavaScript object to local storage, you need to convert it into a JSON string. In the JavaScript Reference application, I use a wrapper around local storage that looks something like this: function Storage() { this.get = function (name) { return JSON.parse(window.localStorage.getItem(name)); }; this.set = function (name, value) { window.localStorage.setItem(name, JSON.stringify(value)); }; this.clear = function () { window.localStorage.clear(); }; }   If you use the wrapper above, then you can add arbitrary JavaScript objects to local storage like this: var store = new Storage(); // Add array to storage var products = [ {name:"Fish", price:2.33}, {name:"Bacon", price:1.33} ]; store.set("products", products); // Retrieve items from storage var products = store.get("products");   Modern browsers support the JSON object natively. If you need the script above to work with older browsers then you should download the JSON2.js library from: https://github.com/douglascrockford/JSON-js The JSON2 library will use the native JSON object if a browser already supports JSON. Merging Server Changes with Browser Local Storage When you first open the JavaScript Reference application, the entire database of JavaScript entries is transferred from the server to the browser. Two items are added to local storage: entries and entriesLastUpdated. The first item contains the entire entries database (a big JSON string of entries). The second item, a timestamp, represents the version of the entries. Whenever you open the JavaScript Reference in the future, the entriesLastUpdated timestamp is passed to the server. Only records that have been deleted, updated, or added since entriesLastUpdated are transferred to the browser. The OData query to get the latest updates looks like this: http://superexpert.com/javascriptreference/Services/EntryService.svc/Entries?$filter=(LastUpdated%20gt%20634301199890494792L) If you remove URL encoding, the query looks like this: http://superexpert.com/javascriptreference/Services/EntryService.svc/Entries?$filter=(LastUpdated gt 634301199890494792L) This query returns only those entries where the value of LastUpdated > 634301199890494792 (the version timestamp). The changes – new JavaScript entries, deleted entries, and updated entries – are merged with the existing entries in local storage. The JavaScript code for performing the merge is contained in the EntriesHelper.js file. The merge() method looks like this:   merge: function (oldEntries, newEntries) { // concat (this performs the add) oldEntries = oldEntries || []; var mergedEntries = oldEntries.concat(newEntries); // sort this.sortByIdThenLastUpdated(mergedEntries); // prune duplicates (this performs the update) mergedEntries = this.pruneDuplicates(mergedEntries); // delete mergedEntries = this.removeIsDeleted(mergedEntries); // Sort this.sortByName(mergedEntries); return mergedEntries; },   The contents of local storage are then updated with the merged entries. I spent several hours writing the merge() method (much longer than I expected). I found two resources to be extremely useful. First, I wrote extensive unit tests for the merge() method. I wrote the unit tests using server-side JavaScript. I describe this approach to writing unit tests in this blog entry. The unit tests are included in the JavaScript Reference source code. Second, I found the following blog entry to be super useful (thanks Nick!): http://nicksnettravels.builttoroam.com/post/2010/08/03/OData-Synchronization-with-WCF-Data-Services.aspx One big challenge that I encountered involved timestamps. I originally tried to store an actual UTC time as the value of the entriesLastUpdated item. I quickly discovered that trying to work with dates in JSON turned out to be a big can of worms that I did not want to open. Next, I tried to use a SQL timestamp column. However, I learned that OData cannot handle the timestamp data type when doing a filter query. Therefore, I ended up using a bigint column in SQL and manually creating the value when a record is updated. I overrode the SaveChanges() method to look something like this: public override int SaveChanges(SaveOptions options) { var changes = this.ObjectStateManager.GetObjectStateEntries( EntityState.Modified | EntityState.Added | EntityState.Deleted); foreach (var change in changes) { var entity = change.Entity as IEntityTracking; if (entity != null) { entity.LastUpdated = DateTime.Now.Ticks; } } return base.SaveChanges(options); }   Notice that I assign Date.Now.Ticks to the entity.LastUpdated property whenever an entry is modified, added, or deleted. Summary After building the JavaScript Reference application, I am convinced that HTML5 local storage can have a dramatic impact on the performance of any data-driven web application. If you are building a web application that involves extensive interaction with data then I recommend that you take advantage of this new feature included in the HTML5 standard.

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