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  • Add Eclipse to Unity Dock in Ubuntu 12.04

    - by csilk
    I'm using the following eclipse.desktop file [1] on the Unity dock but I keep seeing the following error [2] in the ".xsession-errors" file everytime I click the Eclipse icon. Are there any ideas why this is happening? [1] [Desktop Entry] Encoding=UTF-8 Name=Eclipse Comment=Java IDE Exec=/bin/sh /home/USERNAME/eclipse/eclipse Icon=/home/USERNAME/eclipse/icon.png Categories=Application;Development;Java;IDE Version=1.0 Type=Application Terminal=0 [2] /home/USERNAME/eclipse/eclipse: 5: /home/USERNAME/eclipse/eclipse: Syntax error: "(" unexpected

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  • Silverlight Cream for December 08, 2010 -- #1005

    - by Dave Campbell
    In this Issue: Peter Kuhn, David Anson, Jesse Liberty, Mike Taulty(-2-, -3-), Kunal Chowdhury, Jeremy Likness, Martin Krüger, Beth Massi(-2-, -3-)/ Above the Fold: Silverlight: "Rebuilding the PDC 2010 Silverlight Application (Part 1)" Mike Taulty WP7: "WP7: Glossy text block custom control" Martin Krüger Lightswitch: "How to Create a Screen with Multiple Search Parameters in LightSwitch" Beth Massi From SilverlightCream.com: Requirements of and pitfalls in Windows Phone 7 serialization Peter Kuhn discusses Data Contract Serializer issuses on WP7 and how to work around them. Managed implementation of CRC32 and MD5 algorithms updated; new release of ComputeFileHashes for Silverlight, WPF, and the command-line! David Anson ties up some loose ends from a prior post on hash functions, and updates his CRC32 and MD5 algorithms. Windows Phone From Scratch #9 – Visual State Jesse Liberty's latest Windows Phone from Scratch tutorial up... and is on the Visual State... he extends a Button and codes up the State Transitions. Rebuilding the PDC 2010 Silverlight Application (Part 1) Mike Taulty has taken the time to rebuild the PDC2010 Silverlight App that folks wanted the source for... and he's taking multiple posts to explain the heck out of it. This first one is mostly infrastructure. Rebuilding the PDC 2010 Silverlight Application (Part 2) In the 2nd post of the series, Mike Taulty is handling the In/Out of Browser business because he eventually is going to be going OOB. Rebuilding the PDC 2010 Silverlight Application (Part 3) Part 3 finds Mike Taulty delving into WCF Data Services and getting some data on the screen. Paginating Records in Silverlight DataGrid using PagedCollectionView Kunal Chowdhury continues with his investigation of the PagedCollectionView with this post on Pagination of your data. Old School Silverlight Effects If you haven't seen Jeremy Likness' 'Old School' Effects page yet, go just for the entertainment... you'll find yourself hanging around for the code :) WP7: Glossy text block custom control Martin Krüger's latest post is a very cool custom control for WP7 that displays Glossy text... it ain't Metro, but it looks pretty nice... some of it almost like etched text. How to Create a Screen with Multiple Search Parameters in LightSwitch Looks like Beth Massi got a few Lightswitch posts in while I wasn't looking. First up is this one on a multiple-parameter search screen. Adding Static Images and Logos to LightSwitch Applications In the 2nd post, Beth Massi shows how to add your own static images and logos to Lightswitch apps... in response to reader questions. Getting the Most out of LightSwitch Summary Properties In her latest post, Beth Massi explains what Summary Properties are in Lightswitch and how to use them to get the best results for your users. Stay in the 'Light! Twitter SilverlightNews | Twitter WynApse | WynApse.com | Tagged Posts | SilverlightCream Join me @ SilverlightCream | Phoenix Silverlight User Group Technorati Tags: Silverlight    Silverlight 3    Silverlight 4    Windows Phone MIX10

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  • Transition from web-app development to telecom Integration network (IN) layer development

    - by SIJAR
    How difficult it is for someone who has developed web-application using J2EE, Spring etc technology to develop an application for Telecommunication Integration network (IN) layer, the telecom product is to be developed using SS7 stack, JAIN API, J2EE technology. How vital is the knowledge of telecommunication sector? Does anyone anticipate growth in telecommunication sector, what future lies for web development?

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  • Is there a better term than "smoothness" or "granularity" to describe this language feature?

    - by Chris
    One of the best things about programming is the abundance of different languages. There are general purpose languages like C++ and Java, as well as little languages like XSLT and AWK. When comparing languages, people often use things like speed, power, expressiveness, and portability as the important distinguishing features. There is one characteristic of languages I consider to be important that, so far, I haven't heard [or been able to come up with] a good term for: how well a language scales from writing tiny programs to writing huge programs. Some languages make it easy and painless to write programs that only require a few lines of code, e.g. task automation. But those languages often don't have enough power to solve large problems, e.g. GUI programming. Conversely, languages that are powerful enough for big problems often require far too much overhead for small problems. This characteristic is important because problems that look small at first frequently grow in scope in unexpected ways. If a programmer chooses a language appropriate only for small tasks, scope changes can require rewriting code from scratch in a new language. And if the programmer chooses a language with lots of overhead and friction to solve a problem that stays small, it will be harder for other people to use and understand than necessary. Rewriting code that works fine is the single most wasteful thing a programmer can do with their time, but using a bazooka to kill a mosquito instead of a flyswatter isn't good either. Here are some of the ways this characteristic presents itself. Can be used interactively - there is some environment where programmers can enter commands one by one Requires no more than one file - neither project files nor makefiles are required for running in batch mode Can easily split code across multiple files - files can refeence each other, or there is some support for modules Has good support for data structures - supports structures like arrays, lists, and especially classes Supports a wide variety of features - features like networking, serialization, XML, and database connectivity are supported by standard libraries Here's my take on how C#, Python, and shell scripting measure up. Python scores highest. Feature C# Python shell scripting --------------- --------- --------- --------------- Interactive poor strong strong One file poor strong strong Multiple files strong strong moderate Data structures strong strong poor Features strong strong strong Is there a term that captures this idea? If not, what term should I use? Here are some candidates. Scalability - already used to decribe language performance, so it's not a good idea to overload it in the context of language syntax Granularity - expresses the idea of being good just for big tasks versus being good for big and small tasks, but doesn't express anything about data structures Smoothness - expresses the idea of low friction, but doesn't express anything about strength of data structures or features Note: Some of these properties are more correctly described as belonging to a compiler or IDE than the language itself. Please consider these tools collectively as the language environment. My question is about how easy or difficult languages are to use, which depends on the environment as well as the language.

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  • How To: Using spatial data with Entity Framework and Connector/Net

    - by GABMARTINEZ
    One of the new features introduced in Entity Framework 5.0 is the incorporation of some new types of data within an Entity Data Model: the spatial data types. These types allow us to perform operations on coordinates values in an easier way. There's no need to add stored routines or functions for every operation among these geometry types, now the user can have the alternative to put this logic on his application or keep it in the database. In the new 6.7.4 version there's also this new feature incorporated to Connector/Net library so our users can start exploring it and could provide us some feedback or comments about this new functionality. Through this tutorial on how to create a Code First Entity Model with a geometry column, we'll show an example on using Geometry types and some common operations when using geometry types inside an application. Requirements: - Connector/Net 6.7.4 - Entity Framework 5.0 version - .NET Framework 4.5 version - Basic understanding on Entity Framework and C# language. - An installed and running instance of MySQL Server 5.5.x or 5.6.10 version- Visual Studio 2012. Step One: Create a new Console Application  Inside Visual Studio select File->New Project menu option and select the Console Application template. Also make sure the .Net 4.5 version is selected so the new features for EF 5.0 will work with the application. Step Two: Add the Entity Framework Package For adding the Entity Framework Package there is more than one option: the package manager console or the Manage Nuget Packages option dialog. If you want to open the Package Manager Console, go to the Tools Menu -> Library Package Manager -> Package Manager Console. On the Package Manager Console Type:Install-Package EntityFrameworkThis will add the reference to the project of the latest released No alpha version of Entity Framework. Step Three: Adding Entity class and DBContext We'll add a simple class that represents a table entity to save some places and its location using a DBGeometry column that will be mapped to a Geometry type in MySQL. After that some operations can be performed using this data. public class MyPlace { [Key] public int Id { get; set; } public string name { get; set; } public DbGeometry location { get; set; } } public class JourneyDb : DbContext { public DbSet<MyPlace> MyPlaces { get; set; } }  Also make sure to add the connection string to the App.Config file as in the example: <?xml version="1.0" encoding="utf-8"?> <configuration>   <configSections>     <!-- For more information on Entity Framework configuration, visit http://go.microsoft.com/fwlink/?LinkID=237468 -->     <section name="entityFramework" type="System.Data.Entity.Internal.ConfigFile.EntityFrameworkSection, EntityFramework, Version=5.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089" requirePermission="false" />   </configSections>   <startup>     <supportedRuntime version="v4.0" sku=".NETFramework,Version=v4.5" />   </startup>   <connectionStrings>     <add name="JourneyDb" connectionString="server=localhost;userid=root;pwd=;database=journeydb" providerName="MySql.Data.MySqlClient"/>   </connectionStrings>   <entityFramework>     </entityFramework> </configuration> Note also that the <entityFramework> section is empty.Step Four: Adding some new records.On the Program.cs file add the following code for the Main method so the Database gets created and also some new data can be added to the new table. This code adds some records containing some determinate locations. After being added a distance function will be used to know how much distance has each location in reference to the Queens Village Station in New York. static void Main(string[] args)    {     using (JourneyDb cxt = new JourneyDb())      {        cxt.Database.Delete();        cxt.Database.Create();         cxt.MyPlaces.Add(new MyPlace()        {          name = "JFK INTERNATIONAL AIRPORT OF NEW YORK",          location = DbGeometry.FromText("POINT(40.644047 -73.782291)"),        });         cxt.MyPlaces.Add(new MyPlace()        {          name = "ALLEY POND PARK",          location = DbGeometry.FromText("POINT(40.745696 -73.742638)"),        });       cxt.MyPlaces.Add(new MyPlace()        {          name = "CUNNINGHAM PARK",          location = DbGeometry.FromText("POINT(40.735031 -73.768387)"),        });         cxt.MyPlaces.Add(new MyPlace()        {          name = "QUEENS VILLAGE STATION",          location = DbGeometry.FromText("POINT(40.717957 -73.736501)"),        });         cxt.SaveChanges();         var points = (from p in cxt.MyPlaces                      select new { p.name, p.location });        foreach (var item in points)       {         Console.WriteLine("Location " + item.name + " has a distance in Km from Queens Village Station " + DbGeometry.FromText("POINT(40.717957 -73.736501)").Distance(item.location) * 100);       }       Console.ReadKey();      }  }}Output : Location JFK INTERNATIONAL AIRPORT OF NEW YORK has a distance from Queens Village Station 8.69448802402959 Km. Location ALLEY POND PARK has a distance from Queens Village Station 2.84097675104912 Km. Location CUNNINGHAM PARK has a distance from Queens Village Station 3.61695793727275 Km. Location QUEENS VILLAGE STATION has a distance from Queens Village Station 0 Km. Conclusion:Adding spatial data to a table is easier than before when having Entity Framework 5.0. This new Entity Framework feature that handles spatial data columns within the Data layer has a lot of integrated functions and methods toease this type of tasks.Notes:This version of Connector/Net is just released as GA so is preatty much stable to be used on a ProductionEnvironment. Please send us your comments or questions using this blog or at the Forums where we keep answering any questions you have about Connector/Net and MySQL Server.A copy of this sample project can be downloaded here. This application does not include any library so you will haveto add them before running it. Happly MySQL/.Net Coding.

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  • Microphone not capturing sound on 12.04 Lenovo G580

    - by Yam Marcovic
    In both Skype and the Sound Recorder application, I am not capturing any audio from my built-in microphone. I'm not sure why. Otherwise, sound output is working well. I have tried running gstreamer-properties and setting the Default Input plugin to PulseAUdio as well (to match the output), and it didn't help. I have tried running alsamixer -V all and I only get 2 input-related entries: Capture(L R) which is on 100 and not muted (can't be either), and Analog Mic Boost which is on 20db. Extra info: Camera (video) is working well on Skype and Kamerka. Can you please help me get my microphone to work? lspci: 00:00.0 Host bridge: Intel Corporation Ivy Bridge DRAM Controller (rev 09) Subsystem: Lenovo Device 3977 Control: I/O- Mem+ BusMaster+ SpecCycle- MemWINV- VGASnoop- ParErr- Stepping- SERR- FastB2B- DisINTx- Status: Cap+ 66MHz- UDF- FastB2B+ ParErr- DEVSEL=fast >TAbort- <TAbort- <MAbort+ >SERR- <PERR- INTx- Latency: 0 Capabilities: <access denied> Kernel driver in use: agpgart-intel 00:02.0 VGA compatible controller: Intel Corporation Ivy Bridge Graphics Controller (rev 09) (prog-if 00 [VGA controller]) Subsystem: Lenovo Device 3977 Control: I/O+ Mem+ BusMaster+ SpecCycle- MemWINV- VGASnoop- ParErr- Stepping- SERR- FastB2B- DisINTx+ Status: Cap+ 66MHz- UDF- FastB2B+ ParErr- DEVSEL=fast >TAbort- <TAbort- <MAbort- >SERR- <PERR- INTx- Latency: 0 Interrupt: pin A routed to IRQ 42 Region 0: Memory at e0000000 (64-bit, non-prefetchable) [size=4M] Region 2: Memory at d0000000 (64-bit, prefetchable) [size=256M] Region 4: I/O ports at 3000 [size=64] Expansion ROM at <unassigned> [disabled] Capabilities: <access denied> Kernel driver in use: i915 Kernel modules: i915 00:14.0 USB controller: Intel Corporation Panther Point USB xHCI Host Controller (rev 04) (prog-if 30 [XHCI]) Subsystem: Lenovo Device 3977 Control: I/O- Mem+ BusMaster+ SpecCycle- MemWINV- VGASnoop- ParErr- Stepping- SERR- FastB2B- DisINTx+ Status: Cap+ 66MHz- UDF- FastB2B+ ParErr- DEVSEL=medium >TAbort- <TAbort- <MAbort- >SERR- <PERR- INTx- Latency: 0 Interrupt: pin A routed to IRQ 41 Region 0: Memory at e0600000 (64-bit, non-prefetchable) [size=64K] Capabilities: <access denied> Kernel driver in use: xhci_hcd 00:16.0 Communication controller: Intel Corporation Panther Point MEI Controller #1 (rev 04) Subsystem: Lenovo Device 3977 Control: I/O- Mem+ BusMaster+ SpecCycle- MemWINV- VGASnoop- ParErr- Stepping- SERR- FastB2B- DisINTx+ Status: Cap+ 66MHz- UDF- FastB2B- ParErr- DEVSEL=fast >TAbort- <TAbort- <MAbort- >SERR- <PERR- INTx- Latency: 0 Interrupt: pin A routed to IRQ 43 Region 0: Memory at e0614000 (64-bit, non-prefetchable) [size=16] Capabilities: <access denied> Kernel driver in use: mei Kernel modules: mei 00:1a.0 USB controller: Intel Corporation Panther Point USB Enhanced Host Controller #2 (rev 04) (prog-if 20 [EHCI]) Subsystem: Lenovo Device 3977 Control: I/O- Mem+ BusMaster+ SpecCycle- MemWINV- VGASnoop- ParErr- Stepping- SERR- FastB2B- DisINTx- Status: Cap+ 66MHz- UDF- FastB2B+ ParErr- DEVSEL=medium >TAbort- <TAbort- <MAbort- >SERR- <PERR- INTx- Latency: 0 Interrupt: pin A routed to IRQ 16 Region 0: Memory at e0619000 (32-bit, non-prefetchable) [size=1K] Capabilities: <access denied> Kernel driver in use: ehci_hcd 00:1b.0 Audio device: Intel Corporation Panther Point High Definition Audio Controller (rev 04) Subsystem: Lenovo Device 3977 Control: I/O- Mem+ BusMaster+ SpecCycle- MemWINV- VGASnoop- ParErr- Stepping- SERR- FastB2B- DisINTx+ Status: Cap+ 66MHz- UDF- FastB2B- ParErr- DEVSEL=fast >TAbort- <TAbort- <MAbort- >SERR- <PERR- INTx- Latency: 0, Cache Line Size: 64 bytes Interrupt: pin A routed to IRQ 44 Region 0: Memory at e0610000 (64-bit, non-prefetchable) [size=16K] Capabilities: <access denied> Kernel driver in use: snd_hda_intel Kernel modules: snd-hda-intel 00:1c.0 PCI bridge: Intel Corporation Panther Point PCI Express Root Port 1 (rev c4) (prog-if 00 [Normal decode]) Control: I/O+ Mem+ BusMaster+ SpecCycle- MemWINV- VGASnoop- ParErr- Stepping- SERR- FastB2B- DisINTx- Status: Cap+ 66MHz- UDF- FastB2B- ParErr- DEVSEL=fast >TAbort- <TAbort- <MAbort- >SERR- <PERR- INTx- Latency: 0, Cache Line Size: 64 bytes Bus: primary=00, secondary=01, subordinate=01, sec-latency=0 I/O behind bridge: 00002000-00002fff Memory behind bridge: e0500000-e05fffff Secondary status: 66MHz- FastB2B- ParErr- DEVSEL=fast >TAbort- <TAbort- <MAbort- <SERR- <PERR- BridgeCtl: Parity- SERR- NoISA- VGA- MAbort- >Reset- FastB2B- PriDiscTmr- SecDiscTmr- DiscTmrStat- DiscTmrSERREn- Capabilities: <access denied> Kernel driver in use: pcieport Kernel modules: shpchp 00:1c.1 PCI bridge: Intel Corporation Panther Point PCI Express Root Port 2 (rev c4) (prog-if 00 [Normal decode]) Control: I/O+ Mem+ BusMaster+ SpecCycle- MemWINV- VGASnoop- ParErr- Stepping- SERR- FastB2B- DisINTx- Status: Cap+ 66MHz- UDF- FastB2B- ParErr- DEVSEL=fast >TAbort- <TAbort- <MAbort- >SERR- <PERR- INTx- Latency: 0, Cache Line Size: 64 bytes Bus: primary=00, secondary=02, subordinate=02, sec-latency=0 Memory behind bridge: e0400000-e04fffff Secondary status: 66MHz- FastB2B- ParErr- DEVSEL=fast >TAbort- <TAbort- <MAbort- <SERR- <PERR- BridgeCtl: Parity- SERR- NoISA- VGA- MAbort- >Reset- FastB2B- PriDiscTmr- SecDiscTmr- DiscTmrStat- DiscTmrSERREn- Capabilities: <access denied> Kernel driver in use: pcieport Kernel modules: shpchp 00:1d.0 USB controller: Intel Corporation Panther Point USB Enhanced Host Controller #1 (rev 04) (prog-if 20 [EHCI]) Subsystem: Lenovo Device 3977 Control: I/O- Mem+ BusMaster+ SpecCycle- MemWINV- VGASnoop- ParErr- Stepping- SERR- FastB2B- DisINTx- Status: Cap+ 66MHz- UDF- FastB2B+ ParErr- DEVSEL=medium >TAbort- <TAbort- <MAbort- >SERR- <PERR- INTx- Latency: 0 Interrupt: pin A routed to IRQ 23 Region 0: Memory at e0618000 (32-bit, non-prefetchable) [size=1K] Capabilities: <access denied> Kernel driver in use: ehci_hcd 00:1f.0 ISA bridge: Intel Corporation Panther Point LPC Controller (rev 04) Subsystem: Lenovo Device 3977 Control: I/O+ Mem+ BusMaster+ SpecCycle- MemWINV- VGASnoop- ParErr- Stepping- SERR- FastB2B- DisINTx- Status: Cap+ 66MHz- UDF- FastB2B- ParErr- DEVSEL=medium >TAbort- <TAbort- <MAbort- >SERR- <PERR- INTx- Latency: 0 Capabilities: <access denied> Kernel modules: iTCO_wdt 00:1f.2 SATA controller: Intel Corporation Panther Point 6 port SATA Controller [AHCI mode] (rev 04) (prog-if 01 [AHCI 1.0]) Subsystem: Lenovo Device 3977 Control: I/O+ Mem+ BusMaster+ SpecCycle- MemWINV- VGASnoop- ParErr- Stepping- SERR- FastB2B- DisINTx+ Status: Cap+ 66MHz+ UDF- FastB2B+ ParErr- DEVSEL=medium >TAbort- <TAbort- <MAbort- >SERR- <PERR- INTx- Latency: 0 Interrupt: pin B routed to IRQ 40 Region 0: I/O ports at 3088 [size=8] Region 1: I/O ports at 3094 [size=4] Region 2: I/O ports at 3080 [size=8] Region 3: I/O ports at 3090 [size=4] Region 4: I/O ports at 3060 [size=32] Region 5: Memory at e0617000 (32-bit, non-prefetchable) [size=2K] Capabilities: <access denied> Kernel driver in use: ahci 00:1f.3 SMBus: Intel Corporation Panther Point SMBus Controller (rev 04) Subsystem: Lenovo Device 3977 Control: I/O+ Mem+ BusMaster- SpecCycle- MemWINV- VGASnoop- ParErr- Stepping- SERR- FastB2B- DisINTx- Status: Cap- 66MHz- UDF- FastB2B+ ParErr- DEVSEL=medium >TAbort- <TAbort- <MAbort- >SERR- <PERR- INTx- Interrupt: pin C routed to IRQ 10 Region 0: Memory at e0615000 (64-bit, non-prefetchable) [size=256] Region 4: I/O ports at 3040 [size=32] Kernel modules: i2c-i801 01:00.0 Ethernet controller: Atheros Communications Inc. AR8162 Fast Ethernet (rev 08) Subsystem: Lenovo Device 3979 Control: I/O+ Mem+ BusMaster+ SpecCycle- MemWINV- VGASnoop- ParErr- Stepping- SERR- FastB2B- DisINTx- Status: Cap+ 66MHz- UDF- FastB2B- ParErr- DEVSEL=fast >TAbort- <TAbort- <MAbort- >SERR- <PERR- INTx- Latency: 0, Cache Line Size: 64 bytes Interrupt: pin A routed to IRQ 11 Region 0: Memory at e0500000 (64-bit, non-prefetchable) [size=256K] Region 2: I/O ports at 2000 [size=128] Capabilities: <access denied> 02:00.0 Network controller: Atheros Communications Inc. AR9285 Wireless Network Adapter (PCI-Express) (rev 01) Subsystem: Lenovo Device 31a1 Control: I/O+ Mem+ BusMaster+ SpecCycle- MemWINV- VGASnoop- ParErr- Stepping- SERR- FastB2B- DisINTx- Status: Cap+ 66MHz- UDF- FastB2B- ParErr- DEVSEL=fast >TAbort- <TAbort- <MAbort- >SERR- <PERR- INTx- Latency: 0, Cache Line Size: 64 bytes Interrupt: pin A routed to IRQ 17 Region 0: Memory at e0400000 (64-bit, non-prefetchable) [size=64K] Capabilities: <access denied> Kernel driver in use: ath9k Kernel modules: ath9k aplay -l **** List of PLAYBACK Hardware Devices **** card 0: PCH [HDA Intel PCH], device 0: CONEXANT Analog [CONEXANT Analog] Subdevices: 1/1 Subdevice #0: subdevice #0 card 0: PCH [HDA Intel PCH], device 3: HDMI 0 [HDMI 0] Subdevices: 1/1 Subdevice #0: subdevice #0

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  • How can I tell if I am out of inotify watches?

    - by Jorge Castro
    I use an application that consumes inotify watches. I've already set fs.inotify.max_user_watches=32768 in /etc/sysctl.conf but last night the application stopped indexing unless I ran it manually, which leads me to suspect I am out of watches. Since I don't know what the trade off is when I increase this number (does it consume more RAM?), I don't know if I should just increase this number, so I'd like to know if there's a way I can tell if it's using all these watches and what the tradeoffs might be for increasing it.

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  • Webpage loading with wrong content-type after setting up CloudFlare

    - by Daniel Little
    I recently migrated my blog to the Ghost service, I've also setup an alias DNS record with CloudFlare. While showing the blog to a colleague I discovered one of the posts wasn't loading properly and would instead prompt to be downloaded with an application/octet-stream content-type. I can view all the pages without any issues and I believe we're both on the same network as well. Has anyone received a wrong content type like application/octet-stream using CloudFlare, or know what I can do to correct this?

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  • Devoxx 2011: Java EE 6 Hands-on Lab Delivered

    - by arungupta
    I, along with Alexis's help, delivered a Java EE 6 hands-on lab to a packed room of about 40+ attendees at Devoxx 2011. The lab was derived from the OTN Developer Days 2012 version but added lot more content to showcase several Java EE 6 technologies. The problem statement from the lab document states: This hands-on lab builds a typical 3-tier Java EE 6 Web application that retrieves customer information from a database and displays it in a Web page. The application also allows new customers to be added to the database as well. The string-based and type-safe queries are used to query and add rows to the database. Each row in the database table is published as a RESTful resource and is then accessed programmatically. Typical design patterns required by a Web application like validation, caching, observer, partial page rendering, and cross-cutting concerns like logging are explained and implemented using different Java EE 6 technologies. The lab covered Java Persistence API 2, Servlet 3, Enterprise JavaBeans 3.1, JavaServer Faces 2, Java API for RESTful Web Services 1.1, Contexts and Dependency Injection 1.0, and Bean Validation 1.0 over 47 pages of detailed self-paced instructions. Here is the complete Table of Contents: The lab can be downloaded from here and requires only NetBeans IDE "All" or "Java EE" version, which includes GlassFish anyway. All the feedback received from the lab has been incorporated in the instructions and bugs filed (Updated 49559, 205232, 205248, 205256). 80% of the attendees could easily complete the lab and some even completed in much less than 3 hours. That indicates that either more content needs to be added to the lab or the intellectual level of the attendees at the conference was pretty high. I think the lab has enough content for 3 hours but we moved at a much more faster pace so I conclude on the latter. Truly a joy to conduct a lab to 40 Devoxxians! Another related lab that might be handy for folks is "Develop, Deploy, and Monitor your Java EE 6 applications using GlassFish 3.1 Cluster". It explains how: Create a 2-instance GlassFish cluster Front-end with a Web server and a load balancer Demonstrate session replication and fail over Monitor the application using JavaScript The complete lab instructions and source code are available and you can try them. I plan to continue evolving the contents for the Java EE 6 hands-on lab to cover more technologies and features and will announce them on this blog. Let me know on what else would you like to see in the future versions.

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  • Devoxx 2011: Java EE 6 Hands-on Lab Delivered

    - by arungupta
    I, along with Alexis's help, delivered a Java EE 6 hands-on lab to a packed room of about 40+ attendees at Devoxx 2011. The lab was derived from the OTN Developer Days 2012 version but added lot more content to showcase several Java EE 6 technologies. The problem statement from the lab document states: This hands-on lab builds a typical 3-tier Java EE 6 Web application that retrieves customer information from a database and displays it in a Web page. The application also allows new customers to be added to the database as well. The string-based and type-safe queries are used to query and add rows to the database. Each row in the database table is published as a RESTful resource and is then accessed programmatically. Typical design patterns required by a Web application like validation, caching, observer, partial page rendering, and cross-cutting concerns like logging are explained and implemented using different Java EE 6 technologies. The lab covered Java Persistence API 2, Servlet 3, Enterprise JavaBeans 3.1, JavaServer Faces 2, Java API for RESTful Web Services 1.1, Contexts and Dependency Injection 1.0, and Bean Validation 1.0 over 47 pages of detailed self-paced instructions. Here is the complete Table of Contents: The lab can be downloaded from here and requires only NetBeans IDE "All" or "Java EE" version, which includes GlassFish anyway. All the feedback received from the lab has been incorporated in the instructions and bugs filed (Updated 49559, 205232, 205248, 205256). 80% of the attendees could easily complete the lab and some even completed in much less than 3 hours. That indicates that either more content needs to be added to the lab or the intellectual level of the attendees at the conference was pretty high. I think the lab has enough content for 3 hours but we moved at a much more faster pace so I conclude on the latter. Truly a joy to conduct a lab to 40 Devoxxians! Another related lab that might be handy for folks is "Develop, Deploy, and Monitor your Java EE 6 applications using GlassFish 3.1 Cluster". It explains how: Create a 2-instance GlassFish cluster Front-end with a Web server and a load balancer Demonstrate session replication and fail over Monitor the application using JavaScript The complete lab instructions and source code are available and you can try them. I plan to continue evolving the contents for the Java EE 6 hands-on lab to cover more technologies and features and will announce them on this blog. Let me know on what else would you like to see in the future versions.

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  • asus n550jv audio problem: no sound from notebook' speakers

    - by skywalker
    Ubuntu 13.10. The problem is: the internal speakers don't work. I have no problem when I'm using the headphones. There is no hardware issue since in windows 8 everything works perfectly(external subwoofer included). I'm trying to modify /etc/modprobe.d/alsa-base.conf but I can't find the correct model to put into: options snd-hda-intel model= The file HD-Audio-Models.txt doesn't contain the model for ALC668. Some info: :~sudo aplay -l **** List of PLAYBACK Hardware Devices **** card 0: MID [HDA Intel MID], device 3: HDMI 0 [HDMI 0] Subdevices: 1/1 Subdevice #0: subdevice #0 card 0: MID [HDA Intel MID], device 7: HDMI 1 [HDMI 1] Subdevices: 1/1 Subdevice #0: subdevice #0 card 0: MID [HDA Intel MID], device 8: HDMI 2 [HDMI 2] Subdevices: 1/1 Subdevice #0: subdevice #0 card 1: PCH [HDA Intel PCH], device 0: ALC668 Analog [ALC668 Analog] Subdevices: 0/1 Subdevice #0: subdevice #0 :~$ sudo lspci -v | grep -A7 -i "audio" 00:03.0 Audio device: Intel Corporation Xeon E3-1200 v3/4th Gen Core Processor HD Audio Controller (rev 06) Subsystem: Intel Corporation Device 2010 Flags: bus master, fast devsel, latency 0, IRQ 52 Memory at f7a14000 (64-bit, non-prefetchable) [size=16K] Capabilities: [50] Power Management version 2 Capabilities: [60] MSI: Enable+ Count=1/1 Maskable- 64bit- Capabilities: [70] Express Root Complex Integrated Endpoint, MSI 00 Kernel driver in use: snd_hda_intel -- 00:1b.0 Audio device: Intel Corporation 8 Series/C220 Series Chipset High Definition Audio Controller (rev 04) Subsystem: ASUSTeK Computer Inc. Device 11cd Flags: bus master, fast devsel, latency 0, IRQ 53 Memory at f7a10000 (64-bit, non-prefetchable) [size=16K] Capabilities: [50] Power Management version 2 Capabilities: [60] MSI: Enable+ Count=1/1 Maskable- 64bit+ Capabilities: [70] Express Root Complex Integrated Endpoint, MSI 00 Capabilities: [100] Virtual Channel PS info :~$ amixer -c 0 Simple mixer control 'IEC958',0 Capabilities: pswitch pswitch-joined Playback channels: Mono Mono: Playback [on] Simple mixer control 'IEC958',1 Capabilities: pswitch pswitch-joined Playback channels: Mono Mono: Playback [on] Simple mixer control 'IEC958',2 Capabilities: pswitch pswitch-joined Playback channels: Mono Mono: Playback [on] :~$ pacmd dump-volumes Welcome to PulseAudio! Use "help" for usage information. Sink 0: reference = 0: 76% 1: 76%, real = 0: 76% 1: 76%, soft = 0: 100% 1: 100%, current_hw = 0: 76% 1: 76%, save = yes Input 8: volume = 0: 100% 1: 100%, reference_ratio = 0: 100% 1: 100%, real_ratio = 0: 100% 1: 100%, soft = 0: 100% 1: 100%, volume_factor = 0: 100% 1: 100%, volume_factor_sink = 0: 100% 1: 100%, save = no Source 0: reference = 0: 100% 1: 100%, real = 0: 100% 1: 100%, soft = 0: 100% 1: 100%, current_hw = 0: 100% 1: 100%, save = no Source 1: reference = 0: 16% 1: 16%, real = 0: 16% 1: 16%, soft = 0: 100% 1: 100%, current_hw = 0: 16% 1: 16%, save = yes

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  • Google Drive SDK: Writing your First App in Java

    Google Drive SDK: Writing your First App in Java During this session we'll show how to build a complete Java application that uses the Google Drive API to upload a file into the user's Drive account. If you follow along with the presentation, you can have a working Drive command-line application running by the end of the session. From: GoogleDevelopers Views: 0 0 ratings Time: 00:00 More in Science & Technology

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  • App_Offline.htm, taking site down for maintenance

    - by Vipin
    There is much simpler and graceful way to shut down a site while doing upgrade to avoid the problem of people accessing site in the middle of a content update.   Basically, if you place file with name 'app_offline.htm' with below contents in the root of a web application directory, ASP.NET will shut-down the application,  and stop processing any new incoming requests for that application.  ASP.NET will also then respond to all requests for dynamic pages in the application by sending back the content of the app_offline.htm file (for example: you might want to have a “site under construction” or “down for maintenance” message).   Then after upgrade, just rename/delete app_offline.htm file…and the site would be back to normal. Just remember that the size of the file should be greater than 512 bytes, doesn't matter even if you add some comments to it to push the byte size as long as it's of the size greater than 512 - it'll work fine.     <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"><html http://www.w3.org/1999/xhtml"http://www.w3.org/1999/xhtml" ><head>    <title>Maintenance Mode - Outage Message</title></head><body>    <h1>Maintenance Mode</h1>     <p>We're currently undergoing scheduled maintenance. We will come back very shortly.</p>     <p>Sorry for the inconvenience!</p>     <!--            Adding additional hidden content so that IE Friendly Errors don't prevent    this message from displaying (note: it will show a "friendly" 404    error if the content isn't of a certain size).        <h2>Site under maintenance...</h2>      <h2>Site under maintenance...</h2>      <h2>Site under maintenance...</h2>      <h2>Site under maintenance...</h2>      <h2>Site under maintenance...</h2>      <h2>Site under maintenance...</h2>      <h2>Site under maintenance...</h2>      <h2>Site under maintenance...</h2>         --></body></html>

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  • redirecting in node.js behind mod_rewrite proxy

    - by chmanie
    I have a node.js application running behind an Apache mod_rewrite proxy configured in a .htaccess file like this: RewriteCond %{HTTP_HOST} =mydomain.com [OR] RewriteCond %{HTTP_HOST} =www.mydomain.com RewriteRule (.*) http://localhost:3000/$1 [QSA,P] When I now do a redirect (e.g. express' res.redirect()) inside my node.js application (which runs on port 3000), the user is always redirected to http://localhost:3000/ (which is in fact exactly what is defined above but not the desired behaviour). Is there any way around this?

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  • create launcher in unity to be opened in Terminal

    - by Automat
    I would like to make a launcher directed to an application that can only be opened in Terminal. I had it on Maverick and it worked. And also, it added the application to the Installed applications At this moment, on 11.10 I have only made the desktop launcher. If I move it to Unity, it creates a permanent launcher, and it's not in the Installed Apps menu either. I have installed gnome-tweaks-tool. Does anybody have a solution?

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  • ADF Essentials - free version of ADF available for any app server!

    - by Lukasz Romaszewski
    Hello,  that's great news, finally anyone can create and deploy an ADF application on any application server including Oracle's open source Glassfish server without any license! You can use core ADF functionality, namely: Oracle ADF Faces Rich Client Components Oracle ADF Controller Oracle ADF Model Oracle ADF Business Components Some more enterprise grade functionalities still require purchasing the license, among the others: ADF Security (you can use standard JEE security or third party frameworks) MDS (customizations) Web Service Data Control (workaround - use WS proxy and wrap it as a Pojo DC!) Remote Task Flows HA and Clustering You can find more information about this here

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  • Redgate ANTS Performance Profiler

    - by Jon Canning
    Seemingly forever I've been working on a business idea, it's a REST API delivering content to mobiles, and I've never really had much idea about its performance. Yes, I have a suite of unit tests and integration tests, but these only tell me that it works, not how well it works. I was also about to embark on a major refactor, swapping the database from MongoDB to RavenDB, and was curious to see if that impacted performance at all, so I needed a profiler that supported IIS Express that I can run my integration tests against, and Google gave me:   http://www.red-gate.com/supportcenter/content/ANTS_Performance_Profiler/help/7.4/app_iise   Excellent. Following the above guide an instance of IIS Express and is launched, as is Internet Explorer. The latter eventually becomes annoying, I would like to decide whether I want a browser opened, but thankfully the guide is wrong in that it can be closed and profiling will continue. So I ran my tests, stopped profiling, and was presented with a call tree listing the endpoints called and allowing me to drill down to the source code beneath.     Although useful and fascinating this wasn't what I was expecting to see, I was after the method timings from the entire test suite. Switching Show to Methods Grid presented me with a list of my methods, with the slowest lit up in red at the top. Marvellous.     I did find that if you switch to Methods Grid before Call tree has loaded, you do not get the red warnings.   StructureMap was very busy, and next on the list was a request filter that I didn't expect to be so overworked. Highlighting it, the source code was presented to me in the bottom window with timings and a nice red indicator to show me where to look. Oh horror, that reflection hack I put in months ago, I'd forgotten all about it. It was calling Validate<T>() which in turn was resolving a validator from StructureMap. Note to self, use //TODO: when leaving smelly code lying around.     Before refactoring, remember to Save Profile Results from the File menu. Annoyingly you are not prompted to save your results when exiting, and using Save Project will only leave you thankful that you have version control and can go back in time to run your tests again.   Having implemented StructureMap’s ForGenericType, I ran my tests again and:     Win, thankyou ANTS (What does ANTS stand for BTW?)   There's definitely room in my toolbox for a profiler; what started out as idle curiosity actually solved a potential problem. When presented with a new codebase I can see enormous benefit from getting an overview of the pipeline from the call tree before drilling into the code, and as a sanity check before release it gives a little more reassurance that you've done your best, and shows you exactly where to look if you haven’t.   Next I’m going to profile a load test.

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  • Scriptable user-interfaces/frameworks for automated UI testing

    - by AareP
    I'm planning on using scripting for automated UI testing. Main application is written in c#, and I want it to be scriptable, so I can do everything end-user can do, but programmatically. What do you think of software that provides an interface for scripting, like VBA macros in Excel? Can this be future of all programming, big and small? What is the best way to build such an interface for your own application, dll-based or by parsing own scripting language?

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  • Oracle WebCenter: Composite Applications & Mash-Ups

    - by kellsey.ruppel(at)oracle.com
    We’ve talked in previous weeks about the key goals of the new release of WebCenter are providing a Modern User Experience, unparalleled Application Integration, converging all the best of the existing portal platforms into WebCenter and delivering a Common User Experience Architecture.  We’ve provided an overview of Oracle WebCenter and discussed some of the other key goals in previous weeks, and this week, we’ll focus on how with the new release of Oracle WebCenter you can create composite applications and mashups.We recently talked with Sachin Agarwal, Director of Product Management of Enterprise 2.0 at Oracle around the topic of Composite Applications and Mashups. Oracle WebCenter provides a rich set of tools and capabilities for pulling in content, applications and collaboration functionality from various different sources and weaving them together into what we call Mashups. Mashups that also consists of transactional applications from multiple sources are specifically called Composite Applications. With the latest release of Oracle WebCenter one can develop highly productive tasked based interfaces that aggregate a related set of applications that are part of a business process and provide in context collaboration tools so that users don’t have to navigate away to different tabs to achieve these tasks. For instance, a call center representative (CSR), not only needs to be able to pull customer information from a CRM application like Siebel, but also related information from Oracle E-Business Suite about whether a specific order has shipped. The CSR will be far more efficient if he or she does not have to open different tabs to login into multiple applications while the customer is waiting, but can access all this information in one mashup.Oracle WebCenter Suite provides a comprehensive set of tooling that enables a business user to quickly aggregate together a mashup and wire-in different backend applications to create a custom dashboard. Not only does Oracle WebCenter supports a wide set of standards (WSRP 1.0, 2.0, JSR 168, JSR 286) that allow portlets  from other applications to be surfaced within WebCenter, but it also provides tools to bring in other web applications such as .Net Applications  as well as SharePoint webparts. The new Business Mash-up editor allows business users to take any Oracle Application or 3rd party application and wire the backend data sources or APIs to a rich set of visualizations and reuse them in mashups.  Moreover, Business users can customize or personalize any page using Oracle WebCenter Composer’s on-the-fly visual page editing features. Users access and select different resource components available in Oracle WebCenter’s Business Dictionary in order to add new content to the page. The Business Dictionary provides a role-based view of available components or resources, and these components can include information from a variety of enterprise resources such as enterprise applications, managed content, rich media, business processes, or business intelligence systems. Together, Oracle WebCenter’s Composer and Business Dictionary give users access to a powerful, yet easy to use, set of tools to personalize and extend their Oracle WebCenter portals and applications without involving IT.Keep checking back this week as we share more information on how you can easily create Commposite Applications and Mashups with Oracle WebCenter .Technorati Tags: UXP, collaboration, enterprise 2.0, modern user experience, oracle, portals, webcenter, applications, mashups, composite applications

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  • Oracle WebCenter: Composite Applications & Mash-Ups

    - by kellsey.ruppel(at)oracle.com
    We’ve talked in previous weeks about the key goals of the new release of WebCenter are providing a Modern User Experience, unparalleled Application Integration, converging all the best of the existing portal platforms into WebCenter and delivering a Common User Experience Architecture.  We’ve provided an overview of Oracle WebCenter and discussed some of the other key goals in previous weeks, and this week, we’ll focus on how with the new release of Oracle WebCenter you can create composite applications and mashups.We recently talked with Sachin Agarwal, Director of Product Management of Enterprise 2.0 at Oracle around the topic of Composite Applications and Mashups. Oracle WebCenter provides a rich set of tools and capabilities for pulling in content, applications and collaboration functionality from various different sources and weaving them together into what we call Mashups. Mashups that also consists of transactional applications from multiple sources are specifically called Composite Applications. With the latest release of Oracle WebCenter one can develop highly productive tasked based interfaces that aggregate a related set of applications that are part of a business process and provide in context collaboration tools so that users don’t have to navigate away to different tabs to achieve these tasks. For instance, a call center representative (CSR), not only needs to be able to pull customer information from a CRM application like Siebel, but also related information from Oracle E-Business Suite about whether a specific order has shipped. The CSR will be far more efficient if he or she does not have to open different tabs to login into multiple applications while the customer is waiting, but can access all this information in one mashup.Oracle WebCenter Suite provides a comprehensive set of tooling that enables a business user to quickly aggregate together a mashup and wire-in different backend applications to create a custom dashboard. Not only does Oracle WebCenter supports a wide set of standards (WSRP 1.0, 2.0, JSR 168, JSR 286) that allow portlets  from other applications to be surfaced within WebCenter, but it also provides tools to bring in other web applications such as .Net Applications  as well as SharePoint webparts. The new Business Mash-up editor allows business users to take any Oracle Application or 3rd party application and wire the backend data sources or APIs to a rich set of visualizations and reuse them in mashups.  Moreover, Business users can customize or personalize any page using Oracle WebCenter Composer’s on-the-fly visual page editing features. Users access and select different resource components available in Oracle WebCenter’s Business Dictionary in order to add new content to the page. The Business Dictionary provides a role-based view of available components or resources, and these components can include information from a variety of enterprise resources such as enterprise applications, managed content, rich media, business processes, or business intelligence systems. Together, Oracle WebCenter’s Composer and Business Dictionary give users access to a powerful, yet easy to use, set of tools to personalize and extend their Oracle WebCenter portals and applications without involving IT.Keep checking back this week as we share more information on how you can easily create Commposite Applications and Mashups with Oracle WebCenter .Technorati Tags: UXP, collaboration, enterprise 2.0, modern user experience, oracle, portals, webcenter, applications, mashups, composite applications

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  • Oracle WebCenter: Composite Applications & Mash-Ups

    - by kellsey.ruppel(at)oracle.com
    We’ve talked in previous weeks about the key goals of the new release of WebCenter are providing a Modern User Experience, unparalleled Application Integration, converging all the best of the existing portal platforms into WebCenter and delivering a Common User Experience Architecture.  We’ve provided an overview of Oracle WebCenter and discussed some of the other key goals in previous weeks, and this week, we’ll focus on how with the new release of Oracle WebCenter you can create composite applications and mashups.We recently talked with Sachin Agarwal, Director of Product Management of Enterprise 2.0 at Oracle around the topic of Composite Applications and Mashups. Oracle WebCenter provides a rich set of tools and capabilities for pulling in content, applications and collaboration functionality from various different sources and weaving them together into what we call Mashups. Mashups that also consists of transactional applications from multiple sources are specifically called Composite Applications. With the latest release of Oracle WebCenter one can develop highly productive tasked based interfaces that aggregate a related set of applications that are part of a business process and provide in context collaboration tools so that users don’t have to navigate away to different tabs to achieve these tasks. For instance, a call center representative (CSR), not only needs to be able to pull customer information from a CRM application like Siebel, but also related information from Oracle E-Business Suite about whether a specific order has shipped. The CSR will be far more efficient if he or she does not have to open different tabs to login into multiple applications while the customer is waiting, but can access all this information in one mashup.Oracle WebCenter Suite provides a comprehensive set of tooling that enables a business user to quickly aggregate together a mashup and wire-in different backend applications to create a custom dashboard. Not only does Oracle WebCenter supports a wide set of standards (WSRP 1.0, 2.0, JSR 168, JSR 286) that allow portlets  from other applications to be surfaced within WebCenter, but it also provides tools to bring in other web applications such as .Net Applications  as well as SharePoint webparts. The new Business Mash-up editor allows business users to take any Oracle Application or 3rd party application and wire the backend data sources or APIs to a rich set of visualizations and reuse them in mashups.  Moreover, Business users can customize or personalize any page using Oracle WebCenter Composer’s on-the-fly visual page editing features. Users access and select different resource components available in Oracle WebCenter’s Business Dictionary in order to add new content to the page. The Business Dictionary provides a role-based view of available components or resources, and these components can include information from a variety of enterprise resources such as enterprise applications, managed content, rich media, business processes, or business intelligence systems. Together, Oracle WebCenter’s Composer and Business Dictionary give users access to a powerful, yet easy to use, set of tools to personalize and extend their Oracle WebCenter portals and applications without involving IT.Keep checking back this week as we share more information on how you can easily create Commposite Applications and Mashups with Oracle WebCenter .Technorati Tags: UXP, collaboration, enterprise 2.0, modern user experience, oracle, portals, webcenter, applications, mashups, composite applications

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  • Exception Handling And Other Contentious Political Topics

    - by Justin Jones
    So about three years ago, around the time of my last blog post, I promised a friend I would write this post. Keeping promises is a good thing, and this is my first step towards easing back into regular blogging. I fully expect him to return from Pennsylvania to buy me a beer over this. However, it’s been an… ahem… eventful three years or so, and blogging, unfortunately, got pushed to the back burner on my priority list, along with a few other career minded activities. Now that the personal drama of the past three years is more or less resolved, it’s time to put a few things back on the front burner. What I consider to be proper exception handling practices is relatively well known these days. There are plenty of blog posts out there already on this topic which more or less echo my opinions on this topic. I’ll try to include a few links at the bottom of the post. Several years ago I had an argument with a co-worker who posited that exceptions should be caught at every level and logged. This might seem like sanity on the surface, but the resulting error log looked something like this: Error: System.SomeException Followed by small stack trace. Error: System.SomeException Followed by slightly bigger stack trace. Error: System.SomeException Followed by slightly bigger stack trace. Error: System.SomeException Followed by slightly bigger stack trace. Error: System.SomeException Followed by slightly bigger stack trace. Error: System.SomeException Followed by slightly bigger stack trace. Error: System.SomeException Followed by slightly bigger stack trace. Error: System.SomeException Followed by slightly bigger stack trace.   These were all the same exception. The problem with this approach is that the error log, if you run any kind of analytics on in, becomes skewed depending on how far up the stack trace your exception was thrown. To mitigate this problem, we came up with the concept of the “PreLoggedException”. Basically, we would log the exception at the very top level and subsequently throw the exception back up the stack encapsulated in this pre-logged type, which our logging system knew to ignore. Now the error log looked like this: Error: System.SomeException Followed by small stack trace. Much cleaner, right? Well, there’s still a problem. When your exception happens in production and you go about trying to figure out what happened, you’ve lost more or less all context for where and how this exception was thrown, because all you really know is what method it was thrown in, but really nothing about who was calling the method or why. What gives you this clue is the entire stack trace, which we’re losing here. I believe that was further mitigated by having the logging system pull a system stack trace and add it to the log entry, but what you’re actually getting is the stack for how you got to the logging code. You’re still losing context about the actual error. Not to mention you’re executing a whole slew of catch blocks which are sloooooooowwwww……… In other words, we started with a bad idea and kept band-aiding it until it didn’t suck quite so bad. When I argued for not catching exceptions at every level but rather catching them following a certain set of rules, my co-worker warned me “do yourself a favor, never express that view in any future interviews.” I suppose this is my ultimate dismissal of that advice, but I’m not too worried. My approach for exception handling follows three basic rules: Only catch an exception if 1. You can do something about it. 2. You can add useful information to it. 3. You’re at an application boundary. Here’s what that means: 1. Only catch an exception if you can do something about it. We’ll start with a trivial example of a login system that uses a file. Please, never actually do this in production code, it’s just concocted example. So if our code goes to open a file and the file isn’t there, we get a FileNotFound exception. If the calling code doesn’t know what to do with this, it should bubble up. However, if we know how to create the file from scratch we can create the file and continue on our merry way. When you run into situations like this though, What should really run through your head is “How can I avoid handling an exception at all?” In this case, it’s a trivial matter to simply check for the existence of the file before trying to open it. If we detect that the file isn’t there, we can accomplish the same thing without having to handle in in a catch block. 2. Only catch an exception if you can do something about it. Continuing with the poorly thought out file based login system we contrived in part 1, if the code calls a Login(…) method and the FileNotFound exception is thrown higher up the stack, the code that calls Login must account for a FileNotFound exception. This is kind of counterintuitive because the calling code should not need to know the internals of the Login method, and the data file is an implementation detail. What makes more sense, assuming that we didn’t implement any of the good advice from step 1, is for Login to catch the FileNotFound exception and wrap it in a new exception. For argument’s sake we’ll say LoginSystemFailureException. (Sorry, couldn’t think of anything better at the moment.) This gives us two stack traces, preserving the original stack trace in the inner exception, and also is much more informative to the calling code. 3. Only catch an exception if you’re at an application boundary. At some point we have to catch all the exceptions, even the ones we don’t know what to do with. WinForms, ASP.Net, and most other UI technologies have some kind of built in mechanism for catching unhandled exceptions without fatally terminating the application. It’s still a good idea to somehow gracefully exit the application in this case if possible though, because you can no longer be sure what state your application is in, but nothing annoys a user more than an application just exploding. These unhandled exceptions need to be logged, and this is a good place to catch them. Ideally you never want this option to be exercised, but code as though it will be. When you log these exceptions, give them a “Fatal” status (e.g. Log4Net) and make sure these bugs get handled in your next release. That’s it in a nutshell. If you do it right each exception will only get logged once and with the largest stack trace possible which will make those 2am emergency severity 1 debugging sessions much shorter and less frustrating. Here’s a few people who also have interesting things to say on this topic:  http://blogs.msdn.com/b/ericlippert/archive/2008/09/10/vexing-exceptions.aspx http://www.codeproject.com/Articles/9538/Exception-Handling-Best-Practices-in-NET I know there’s more but I can’t find them at the moment.

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  • Oracle Magazine, March/April 2010

    Oracle Magazine March/April features articles on enterprise software applications, application grid architecture, partitions, Tom Kyte on Edition-Based Redefinition, Oracle Application Express and much more.

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  • Building Performance Metrics into ASP.NET MVC Applications

    When you're instrumenting an ASP.NET MVC or Web API application to monitor its performance while it is running, it makes sense to use custom performance counters.There are plenty of tools available that read performance counter data, report on it and create alerts based on it. You can then plot application metrics against all sorts of server and workstation metrics.This way, there will always be the right data to guide your tuning efforts.

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