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• Command line tool in python in a fixed root directory ...

  - by koleto

  I would like to install my python application as a command line tool that should work entirelly inside the install directory (for example C:\Python26\Lib\site-packages\application) The problem is I would like to reffer in runtime to the submodules and resources from within the application directory three. If I install the app with [console_scripts] option the default path is the current directory. Is there a elegant way to keep the current execution path of the application to the site-packages directory? Thanks

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• Application Performance Episode 2: Announcing the Judges!

  - by Michaela Murray

  The story so far… We’re writing a new book for ASP.NET developers, and we want you to be a part of it! If you work with ASP.NET applications, and have top tips, hard-won lessons, or sage advice for avoiding, finding, and fixing performance problems, we want to hear from you! And if your app uses SQL Server, even better – interaction with the database is critical to application performance, so we’re looking for database top tips too. There’s a Microsoft Surface apiece for the person who comes up with the best tip for SQL Server and the best tip for .NET. Of course, if your suggestion is selected for the book, you’ll get full credit, by name, Twitter handle, GitHub repository, or whatever you like. To get involved, just email your nuggets of performance wisdom to [email protected] – there are examples of what we’re looking for and full competition details at Application Performance: The Best of the Web. Enter the judges… As mentioned in my last blogpost, we have a mystery panel of celebrity judges lined up to select the prize-winning performance pointers. We’re now ready to reveal their secret identities! Judging your ASP.NET  tips will be: Jean-Phillippe Gouigoux, MCTS/MCPD Enterprise Architect and MVP Connected System Developer. He’s a board member at French software company MGDIS, and teaches algorithms, security, software tests, and ALM at the Université de Bretagne Sud. Jean-Philippe also lectures at IT conferences and writes articles for programming magazines. His book Practical Performance Profiling is published by Simple-Talk. Nik Molnar,  a New Yorker, ASP Insider, and co-founder of Glimpse, an open source ASP.NET diagnostics and debugging tool. Originally from Florida, Nik specializes in web development, building scalable, client-centric solutions. In his spare time, Nik can be found cooking up a storm in the kitchen, hanging with his wife, speaking at conferences, and working on other open source projects. Mitchel Sellers, Microsoft C# and DotNetNuke MVP. Mitchel is an experienced software architect, business leader, public speaker, and educator. He works with companies across the globe, as CEO of IowaComputerGurus Inc. Mitchel writes technical articles for online and print publications and is the author of Professional DotNetNuke Module Programming. He frequently answers questions on StackOverflow and MSDN and is an active participant in the .NET and DotNetNuke communities. Clive Tong, Software Engineer at Red Gate. In previous roles, Clive spent a lot of time working with Common LISP and enthusing about functional languages, and he’s worked with managed languages since before his first real job (which was a long time ago). Long convinced of the productivity benefits of managed languages, Clive is very interested in getting good runtime performance to keep managed languages practical for real-world development. And our trio of SQL Server specialists, ready to select your top suggestion, are (drumroll): Rodney Landrum, a SQL Server MVP who writes regularly about Integration Services, Analysis Services, and Reporting Services. He’s authored SQL Server Tacklebox, three Reporting Services books, and contributes regularly to SQLServerCentral, SQL Server Magazine, and Simple–Talk. His day job involves overseeing a large SQL Server infrastructure in Orlando. Grant Fritchey, Product Evangelist at Red Gate and SQL Server MVP. In an IT career spanning more than 20 years, Grant has written VB, VB.NET, C#, and Java. He’s been working with SQL Server since version 6.0. Grant volunteers with the Editorial Committee at PASS and has written books for Apress and Simple-Talk. Jonathan Allen, leader and founder of the PASS SQL South West user group. He’s been working with SQL Server since 1999 and enjoys performance tuning, development, and using SQL Server for business solutions. He’s spoken at SQLBits and SQL in the City, as well as local user groups across the UK. He’s also a moderator at ask.sqlservercentral.com.

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• Implementing a modern web application with Web API on top of old services

  - by Gaui

  My company has many WCF services which may or may not be replaced in the near future. The old web application is written in WebForms and communicates straight with these services via SOAP and returns DataTables. Now I am designing a new modern web application in a modern style, an AngularJS client which communicates with an ASP.NET Web API via JSON. The Web API then communicates with the WCF services via SOAP. In the future I want to let the Web API handle all requests and go straight to the database, but because the business logic implemented in the WCF services is complicated it's going to take some time to rewrite and replace it. Now to the problem: I'm trying to make it easy in the near future to replace the WCF services with some other data storage, e.g. another endpoint, database or whatever. I also want to make it easy to unit test the business logic. That's why I have structured the Web API with a repository layer and a service layer. The repository layer has a straight communication with the data storage (WCF service, database, or whatever) and the service layer then uses the repository (Dependency Injection) to get the data. It doesn't care where it gets the data from. Later on I can be in control and structure the data returned from the data storage (DataTable to POCO) and be able to test the logic in the service layer with some mock repository (using Dependency Injection). Below is some code to explain where I'm going with this. But my question is, does this all make sense? Am I making this overly complicated and could this be simplified in any way possible? Does this simplicity make this too complicated to maintain? My main goal is to make it as easy as possible to switch to another data storage later on, e.g. an ORM and be able to test the logic in the service layer. And because the majority of the business logic is implemented in these WCF services (and they return DataTables), I want to be in control of the data and the structure returned to the client. Any advice is greatly appreciated. Update 20/08/14 I created a repository factory, so services would all share repositories. Now it's easy to mock a repository, add it to the factory and create a provider using that factory. Any advice is much appreciated. I want to know if I'm making things more complicated than they should be. So it looks like this: 1. Repository Factory public class RepositoryFactory { private Dictionary<Type, IServiceRepository> repositories; public RepositoryFactory() { this.repositories = new Dictionary<Type, IServiceRepository>(); } public void AddRepository<T>(IServiceRepository repo) where T : class { if (this.repositories.ContainsKey(typeof(T))) { this.repositories.Remove(typeof(T)); } this.repositories.Add(typeof(T), repo); } public dynamic GetRepository<T>() { if (this.repositories.ContainsKey(typeof(T))) { return this.repositories[typeof(T)]; } throw new RepositoryNotFoundException("No repository found for " + typeof(T).Name); } } I'm not very fond of dynamic but I don't know how to retrieve that repository otherwise. 2. Repository and service // Service repository interface // All repository interfaces extend this public interface IServiceRepository { } // Invoice repository interface // Makes it easy to mock the repository later on public interface IInvoiceServiceRepository : IServiceRepository { List<Invoice> GetInvoices(); } // Invoice repository // Connects to some data storage to retrieve invoices public class InvoiceServiceRepository : IInvoiceServiceRepository { public List<Invoice> GetInvoices() { // Get the invoices from somewhere // This could be a WCF, a database, or whatever using(InvoiceServiceClient proxy = new InvoiceServiceClient()) { return proxy.GetInvoices(); } } } // Invoice service // Service that handles talking to a real or a mock repository public class InvoiceService { // Repository factory RepositoryFactory repoFactory; // Default constructor // Default connects to the real repository public InvoiceService(RepositoryFactory repo) { repoFactory = repo; } // Service function that gets all invoices from some repository (mock or real) public List<Invoice> GetInvoices() { // Query the repository return repoFactory.GetRepository<IInvoiceServiceRepository>().GetInvoices(); } }

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• Logging errors caused by exceptions deep in the application

  - by Kaleb Pederson

  What are best-practices for logging deep within an application's source? Is it bad practice to have multiple event log entries for a single error? For example, let's say that I have an ETL system whose transform step involves: a transformer, pipeline, processing algorithm, and processing engine. In brief, the transformer takes in an input file, parses out records, and sends the records through the pipeline. The pipeline aggregates the results of the processing algorithm (which could do serial or parallel processing). The processing algorithm sends each record through one or more processing engines. So, I have at least four levels: Transformer - Pipeline - Algorithm - Engine. My code might then look something like the following: class Transformer { void Process(InputSource input) { try { var inRecords = _parser.Parse(input.Stream); var outRecords = _pipeline.Transform(inRecords); } catch (Exception ex) { var inner = new ProcessException(input, ex); _logger.Error("Unable to parse source " + input.Name, inner); throw inner; } } } class Pipeline { IEnumerable<Result> Transform(IEnumerable<Record> records) { // NOTE: no try/catch as I have no useful information to provide // at this point in the process var results = _algorithm.Process(records); // examine and do useful things with results return results; } } class Algorithm { IEnumerable<Result> Process(IEnumerable<Record> records) { var results = new List<Result>(); foreach (var engine in Engines) { foreach (var record in records) { try { engine.Process(record); } catch (Exception ex) { var inner = new EngineProcessingException(engine, record, ex); _logger.Error("Engine {0} unable to parse record {1}", engine, record); throw inner; } } } } } class Engine { Result Process(Record record) { for (int i=0; i<record.SubRecords.Count; ++i) { try { Validate(record.subRecords[i]); } catch (Exception ex) { var inner = new RecordValidationException(record, i, ex); _logger.Error( "Validation of subrecord {0} failed for record {1}", i, record ); } } } } There's a few important things to notice: A single error at the deepest level causes three log entries (ugly? DOS?) Thrown exceptions contain all important and useful information Logging only happens when failure to do so would cause loss of useful information at a lower level. Thoughts and concerns: I don't like having so many log entries for each error I don't want to lose important, useful data; the exceptions contain all the important but the stacktrace is typically the only thing displayed besides the message. I can log at different levels (e.g., warning, informational) The higher level classes should be completely unaware of the structure of the lower-level exceptions (which may change as the different implementations are replaced). The information available at higher levels should not be passed to the lower levels. So, to restate the main questions: What are best-practices for logging deep within an application's source? Is it bad practice to have multiple event log entries for a single error?

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• How can I find out if the MainActivity is being paused from my Java class?

  - by quinestor

  I am using motion sensor detection in my application. My design is this: a class gets the sensor services references from the main activity and then it implements SensorEventListener. That is, the MainActivity does not listen for sensor event changes: public void onCreate(Bundle savedInstanceState) { // ... code mSensorManager = (SensorManager) getSystemService(Context.SENSOR_SERVICE); mAccelerometer = mSensorManager.getDefaultSensor(Sensor.TYPE_ACCELEROMETER); // The following is my java class, it does not extends any android fragment/activty mShakeUtil = new ShakeUtil(mSensorManager,mAccelerometer,this); // ..more code.. } I can't redesign ShakeUtil so it is a fragment nor activity, unfortunately. Now to illustrate the problem consider: MainActivity is on its way to be destroyed/paused. I.e screen rotation ShakeUtil's onSensorChanged(SensorEvent event) gets called in the process.. One of the things that happen inside onSensorChanged is a dialog interaction, which gives the error: java.lang.IllegalStateException: Can not perform this action after onSaveInstanceState When the previous happens between MainActivity's onSaveInstanceState and onPause. I know this can be prevented if I successfully detect that MainActivity is being pause in ShakeUtil. How can I detect that MainActivity is being paused or onSaveInstanceState was called from ShakeUtil? Alternatively, how can I avoid this issue without making Shakeutil extend activity? So far I have tried with flag variables but that isn't good enough, I guess these are not atomic operations. I tried using Activity's isChangingConfigurations(), but I get an undocummented "NoSuchMethodFound" error.. I am unregistering the sensors by calling ShakeUtil when onPause in main ACtivity

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• How to track deleted self-tracking entities in ObservableCollection without memory leaks

  - by Yannick M.

  In our multi-tier business application we have ObservableCollections of Self-Tracking Entities that are returned from service calls. The idea is we want to be able to get entities, add, update and remove them from the collection client side, and then send these changes to the server side, where they will be persisted to the database. Self-Tracking Entities, as their name might suggest, track their state themselves. When a new STE is created, it has the Added state, when you modify a property, it sets the Modified state, it can also have Deleted state but this state is not set when the entity is removed from an ObservableCollection (obviously). If you want this behavior you need to code it yourself. In my current implementation, when an entity is removed from the ObservableCollection, I keep it in a shadow collection, so that when the ObservableCollection is sent back to the server, I can send the deleted items along, so Entity Framework knows to delete them. Something along the lines of: protected IDictionary<int, IList> DeletedCollections = new Dictionary<int, IList>(); protected void SubscribeDeletionHandler<TEntity>(ObservableCollection<TEntity> collection) { var deletedEntities = new List<TEntity>(); DeletedCollections[collection.GetHashCode()] = deletedEntities; collection.CollectionChanged += (o, a) => { if (a.OldItems != null) { deletedEntities.AddRange(a.OldItems.Cast<TEntity>()); } }; } Now if the user decides to save his changes to the server, I can get the list of removed items, and send them along: ObservableCollection<Customer> customers = MyServiceProxy.GetCustomers(); customers.RemoveAt(0); MyServiceProxy.UpdateCustomers(customers); At this point the UpdateCustomers method will verify my shadow collection if any items were removed, and send them along to the server side. This approach works fine, until you start to think about the life-cycle these shadow collections. Basically, when the ObservableCollection is garbage collected there is no way of knowing that we need to remove the shadow collection from our dictionary. I came up with some complicated solution that basically does manual memory management in this case. I keep a WeakReference to the ObservableCollection and every few seconds I check to see if the reference is inactive, in which case I remove the shadow collection. But this seems like a terrible solution... I hope the collective genius of StackOverflow can shed light on a better solution. Thanks!

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• andriod emulator application deployment error.

  - by user288686

  Hi Fellows, I have developed an application in Rhodes framework and deployed the application in an android emulator. When i try to access the application i get the following error, SD card error,Application cant access the SD card while its mounted.Please unmount the device and stop the adb server before launching the application. i have tried to unmount the SD card in the emulator but i am unable to do that. Any help will be of great use. Thanks in advance, Karthik.

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• Per Application Packet Analyzer

  - by Anindya Chatterjee

  Is there any tool which can analyze network traffic per application? Wireshark does not have per application filtering, fiddler also does not give proper logging for any application. So can anyone please help me out to find an app which can analyze network traffic originating from a random application and log the traffic for that particular application only?

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• How to immediately terminate crashed application?

  - by FractalizeR

  Hello. I have an application that sometimes causes exceptions. And I need to restart it if it crashed. But the problem is, that I have Windows 7 here and when application crashes, Windows shows me nice dialog box with a suggestion to close the application. But the application itself is still running until I click "Close". How to get rid of this Window and make application terminate immediately without any dialog boxes?

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• analytics about a particular application launched at apple appstore

  - by thndrkiss

  Hi, Is there a way to find the unique users who downloaded an application, score rated by user when he deletes the application, no of times the application was installed by the same user, no of users who have deleted their application and other things which are kind of analytics about the application launched at apples appstore.

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• ASP.NET- forcing child/container events to fire before parent onload?

  - by Hans Gruber

  I'm working on a questionnaire type application in which questions are stored in a database. Therefore, I create my controls dynamically on every Page.OnLoad. This works like a charm and ViewState is persisted between postbacks because I ensure that my dynamic controls always have the same generated Control.ID. In addition to the user control that dynamically populates the questions, my questionnaire page also contains a 'Status' section (also encapsulated by a user control) which represents the status of the questionnaire (choices are 'Complete', 'Started' or 'In Progress'). If the user changes the status of questionnaire (i.e. from 'In Progress' to 'Complete'), I need to postback to the server because the contents of the dynamic portion of the questionnaire depend on the selected status. Some questions are always present regardless of status, and yet others may not be present at all for the selected status. The point is, when the status changes, I have to postback to the page and render the right set of questions. Additionally, I need to preserve any user entered values for those questions which are 'always available'. However, due to the page life cycle in ASP.NET, the 'Status' user control's OnLoad, which contains the correct status needed to load the right questions from the DB, doesn't get executed until after the 'dynamic questions' user control has already been populated (with the wrong/stale values). To get around this, I raise an event from my 'Status' user control to the main page to indicate that the Status has changed. The main page then raises an event on the 'dynamic questions' user control. Since by the time this event bubbles up, the 'dynamic questions' user control has already loaded the 'wrong' questions from the DB, it first calls Controls.Clear. It then happily uses the new status to query the database for the 'correct' questions and does a Control.Add() on each. FYI, Control.IDs are consistent across postbacks. This solution works...sorta. The correct set of questions for the selected status do get rendered; however ViewState is getting lost for those 'always available' questions. I'm guessing this is because the 'dynamic questions' user control calls Controls.Clear when responding to the status changed event. This must somehow kill the association between ViewState and my dynamic controls, even though the Control.ID are consistent. This seems like such a common requirement, I'm virtually certain there is a better, cleaner and less error prone approach to accomplish this. In case its not plain obvious, I haven't been able to grok the ASP.NET page life-cycle despite working with it for the last year. Any help is much appreciated!

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• How to create Chat application using Servlets & JSP

  - by Crazy boy

  I want to create chat application using Servlets & JSP. May I know how can I create chat application as I have never created before? How much knowledge I need to have to create chat application? Is there any need of networking API to create chat application? What's the design pattern I need to follow to create that application? Is there any need of database?

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• How to launch java application from Dock, Mac

  - by Sunil Kumar Sahoo

  I have created a Java Swing application. It works fine. I have created application file (.app) for that application using jar bundler. But the main problem is that my application does not open if I click it on the Dock. I am using Mac OS. How I can launch my application by clicking on Dock Thanks Sunil Kumar Sahoo

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• Android register to remote server on first application uses

  - by cppdev

  Hi, I am writing a android application where I want to register my application to remoter server when application is first launched on installation. Application will register to remoter server itself without taking any user input. How Can I track whether this is a first application launch after installation ?

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• configure mvc.net application on facebook

  - by munish

  I have integrated facebook in my application mvc.net application. I have configured my apllication on face book with the url : http://localhost:portnumber/Home/Test?Return="ok" when i run the application then it opened pop up of facebook having two text boexs for user name and password with warning message: "Given URL is not allowed by the Application configuration" In my application Test is the name of Action method of controller Please suggest me how to handle this. Thanks Munish

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• How to Read texfile etch.. from Application folder where Application is Installed?

  - by Crimsonland

  I Added textfile on my Application Folder where the application is also located. I having a problem where to locate and read the content of the texfile regarding what location the users specify the application to be installed. Example: CASE 1: If Application Installed on C Get the path of: C:\Textfile.txt CASE 2:If Application Installed on Program files Get the path of C:\Program Files\Default Company Name\Textfile.Text Thanks in Regards.

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• How do I get the application title of a Google AppEngine app from within that app

  - by Noah McIlraith

  Under the application settings page in the Administration console, it is possible to specify a name for the application, AFAIK this is used in the login page when using the users API to login. I would like to be able to use this information within an application, currently, the title is also specified in a separate configuration file, but configuration repetition is something I would like to avoid if at all possible. Is there some way for a GAE application to determine the "Application Title"? Oh, also, I am using python.

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• Code for Waterglen Horse Farms application? [migrated]

  - by user73459

  I am having trouble with the solution to the Waterglens Horse Farms application in the Visual Basic 2010 Reloaded book. The problem reads: Each year Sabrina Cantrell, owner of waterglen horse farms enters four of her horses in five local horse races. She uses the table shown below to keep track of her horses in 5 local races. in the table , a 1 shows that the horse won a race, a 2 shows 2nd place, a 3 is 3rd place , and a 0 the horse didn't finish in the top 3. More details in these 2 images: http://imgur.com/a/YTNEX Here is what I have tried so far: Dim racescores(,) As Integer = {{0, 1, 0, 3, 2}, {1, 0, 2, 0, 0}, {0, 3, 0, 1, 0}, {3, 2, 1, 0, 0}} Dim subscript As Integer = 0 Dim noplace As Integer = 0 If horse1RadioButton.Checked Then Do While subscript < racescores(3, 4) If racescores(0, subscript) = 0 Then noplace = noplace + 1 End If subscript = subscript + 1 Loop noPlaceDisplayLabel.Text = noplace End If

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• Looking for VPS Hosting for a LAMP Web Application

  - by Ali

  Hi guys, Trying to find a Managed VPS Hosting Solution for a LAMP Web Application. The more CPU, RAM, and Disk space the better Don't need a huge amount of bandwidth for now Would like to be able to easily grow into a stronger server Have really responsive, dedicated, smart support staff -- our current hosting is just terrible My main problem is that I can't even find a non-biased website out there that does a proper comparison of VPS Hosting providers. Can anybody either suggest a reviews/ranking site or a hosting with proven record? How would you go about finding the best hosting service? Thanks a lot! Ali

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• Building a Store Locator ASP.NET Application Using Google Maps API (Part 3)

  Over the past two weeks I've showed how to build a store locator application using ASP.NET and the free <a href="http://code.google.com/apis/maps/">Google Maps API</a> and Google's geocoding service. <a href="http://www.4guysfromrolla.com/articles/051910-1.aspx">Part 1</a> looked at creating the database to record the store locations. This database contains a table named <code>Stores</code> with columns capturing each store's address and <a href="http://en.wikipedia.org/wiki/Latitude">latitude</a> and <a href="http://en.wikipedia.org/wiki/Longitude">longitude</a> coordinates. Part 1 also showed how to use Google's geocoding service to translate a user-entered address

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• OTN Developer Day: Oracle Database 11g Application Development

  - by stephen.garth

  When and Where: Tuesday June 15, 2010 from 8:00 am - 5:30 pm Hyatt Regency Reston, Reston VA This full-day FREE event offers a great learning and networking opportunity. With support from Oracle database application development experts, you'll get valuable hands-on experience developing database-backed apps with the latest Oracle tools and frameworks. Oh yeah, you get to use your own notebook and download some cool and very useful materials. Find out more and register here. var gaJsHost = (("https:" == document.location.protocol) ? "https://ssl." : "http://www."); document.write(unescape("%3Cscript src='" + gaJsHost + "google-analytics.com/ga.js' type='text/javascript'%3E%3C/script%3E")); try { var pageTracker = _gat._getTracker("UA-13185312-1"); pageTracker._trackPageview(); } catch(err) {}

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• DAL Exception handling in a MVP application

  - by Chathuranga

  In a MVP win forms application I'm handling exceptions as follows in DAL. Since the user messaging is not a responsibility of DAL, I want to move it in to my Presentation class. Could you show me a standard way to do that? public bool InsertAccount(IBankAccount ba) { string selectStatement = @"IF NOT EXISTS (SELECT ac_no FROM BankAccount WHERE ac_no=@ac_no) BEGIN INSERT INTO BankAccount ..."; using (SqlConnection sqlConnection = new SqlConnection(db.ConnectionString)) { using (SqlCommand sqlCommand = new SqlCommand(selectStatement, sqlConnection)) { try { sqlConnection.Open(); sqlCommand.Parameters.Add("@ac_no", SqlDbType.Char).Value = ba.AccountNumber; // // sqlCommand.ExecuteNonQuery(); return true; } catch (Exception e) { MessageBox.Show(("Error: " + e.Message)); } if (sqlConnection.State == System.Data.ConnectionState.Open) sqlConnection.Close(); return false; } } }

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• UKOUG Application Server & Middleware SIG Meeting

  - by JuergenKress

  Date: Wednesday 10th Oct 2012 Time: 09:00 - 16:00 Location: Reading Venue: Oracle, Thames Valley Park, Reading Agenda: 09:00 Registration and Coffee 10:00 Welcome Application Server & Middleware Committee 10:10 Oracle Support Updates Nick Pounder, Oracle Customer Services 10:30 OpenWorld 2012 - News Round-up for Middleware Admins Simon Haslam, Veriton Limited 11:00 Coffee break 11:20 Oracle Single-Sign on to Oracle Access Manager Migration Rob Otto, Oracle Consulting Services UK 12:05 Supporting Fusion Middleware through First Failure Capture (theory) Greg Cook, Oracle 12:50 Lunch and Network 13:35 Deputy Chair Elections UKOUG 13:45 Supporting Fusion Middleware through First Failure Capture (demos) Greg Cook, Oracle 14:15 Networking session including tea/coffee 14:45 Real Life WebLogic Performance Tuning: Tales and Techniques from the Field Steve Millidge, C2B2 Consulting Limited 15:30 WLST: WebLogic's Swiss Army Knife Simon Haslam, Veriton Limited 15:45 AOB and Close For details please visit the registration page. WebLogic Partner Community For regular information become a member in the WebLogic Partner Community please visit: http://www.oracle.com/partners/goto/wls-emea ( OPN account required). If you need support with your account please contact the Oracle Partner Business Center. BlogTwitterLinkedInMixForumWiki Technorati Tags: UK user group,Simon Haslam,WebLogic Community,Oracle,OPN,Jürgen Kress

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• Analysing and measuring the performance of a .NET application (survey results)

  - by Laila

  Back in December last year, I asked myself: could it be that .NET developers think that you need three days and a PhD to do performance profiling on their code? What if developers are shunning profilers because they perceive them as too complex to use? If so, then what method do they use to measure and analyse the performance of their .NET applications? Do they even care about performance? So, a few weeks ago, I decided to get a 1-minute survey up and running in the hopes that some good, hard data would clear the matter up once and for all. I posted the survey on Simple Talk and got help from a few people to promote it. The survey consisted of 3 simple questions: Amazingly, 533 developers took the time to respond - which means I had enough data to get representative results! So before I go any further, I would like to thank all of you who contributed, because I now have some pretty good answers to the troubling questions I was asking myself. To thank you properly, I thought I would share some of the results with you. First of all, application performance is indeed important to most of you. In fact, performance is an intrinsic part of the development cycle for a good 40% of you, which is much higher than I had anticipated, I have to admit. (I know, "Have a little faith Laila!") When asked what tool you use to measure and analyse application performance, I found that nearly half of the respondents use logging statements, a third use performance counters, and 70% of respondents use a profiler of some sort (a 3rd party performance profilers, the CLR profiler or the Visual Studio profiler). The importance attributed to logging statements did surprise me a little. I am still not sure why somebody would go to the trouble of manually instrumenting code in order to measure its performance, instead of just using a profiler. I personally find the process of annotating code, calculating times from log files, and relating it all back to your source terrifyingly laborious. Not to mention that you then need to remember to turn it all off later! Even when you have logging in place throughout all your code anyway, you still have a fair amount of potentially error-prone calculation to sift through the results; in addition, you'll only get method-level rather than line-level timings, and you won't get timings from any framework or library methods you don't have source for. To top it all, we all know that bottlenecks are rarely where you would expect them to be, so you could be wasting time looking for a performance problem in the wrong place. On the other hand, profilers do all the work for you: they automatically collect the CPU and wall-clock timings, and present the results from method timing all the way down to individual lines of code. Maybe I'm missing a trick. I would love to know about the types of scenarios where you actively prefer to use logging statements. Finally, while a third of the respondents didn't have a strong opinion about code performance profilers, those who had an opinion thought that they were mainly complex to use and time consuming. Three respondents in particular summarised this perfectly: "sometimes, they are rather complex to use, adding an additional time-sink to the process of trying to resolve the existing problem". "they are simple to use, but the results are hard to understand" "Complex to find the more advanced things, easy to find some low hanging fruit". These results confirmed my suspicions: Profilers are seen to be designed for more advanced users who can use them effectively and make sense of the results. I found yet more interesting information when I started comparing samples of "developers for whom performance is an important part of the dev cycle", with those "to whom performance is only looked at in times of crisis", and "developers to whom performance is not important, as long as the app works". See the three graphs below. Sample of developers to whom performance is an important part of the dev cycle: Sample of developers to whom performance is important only in times of crisis: Sample of developers to whom performance is not important, as long as the app works: As you can see, there is a strong correlation between the usage of a profiler and the importance attributed to performance: indeed, the more important performance is to a development team, the more likely they are to use a profiler. In addition, developers to whom performance is an important part of the dev cycle have a higher tendency to use a much wider range of methods for performance measurement and analysis. And, unsurprisingly, the less important performance is, the less varied the methods of measurement are. So all in all, to come back to my random questions: .NET developers do care about performance. Those who care the most use a wider range of performance measurement methods than those who care less. But overall, logging statements, performance counters and third party performance profilers are the performance measurement methods of choice for most developers. Finally, although most of you find code profilers complex to use, those of you who care the most about performance tend to use profilers more than those of you to whom performance is not so important.

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• Storing large data in HTTP Session (Java Application)

  - by Umesh Awasthi

  I am asking this question in continuation with http-session-or-database-approach. I am planning to follow this approach. When user add product to cart, create a Cart Model, add items to cart and save to DB. Convert Cart model to cart data and save it to HTTP session. Any update/ edit update underlying cart in DB and update data snap shot in Session. When user click on view cart page, just pick cart data from Session and display to customer. I have following queries regarding HTTP Session How good is it to store large data (Shopping Cart) in Session? How scalable this approach can be ? (With respect to Session) Won't my application going to eat and demand a lot of memory? Is my approach is fine or do i need to consider other points while designing this? Though, we can control what all cart data should be stored in the Session, but still we need to have certain information in cart data being stored in session?

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