application data - Page 178

Solar Power Your Data Center Into the Future

Hard-Core Hardware: The age of solar power is fast arriving, and it may be keeping the lights on in a data center near you. The former downsides, chiefly cost constraints, no longer apply.

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Google I/O 2012 - Powering Your Application's Data using Google Cloud Storage

Google I/O 2012 - Powering Your Application's Data using Google Cloud Storage Navneet Joneja, Nathan Herring Since opening its doors to all developers at Google I/O last year, the Google Cloud Storage team has shipped several features that let you use Google Cloud Storage for a variety of advanced use cases. This session will open with a quick introduction to the product, and quickly shift focus to implementing a variety of advanced applications using new features in Google Cloud Storage. For all I/O 2012 sessions, go to developers.google.com From: GoogleDevelopers Views: 48 1 ratings Time: 58:32 More in Science & Technology

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ANSI SQL Hierarchical Data Processing Basics

The SQL-92 standard unknowingly and without planning introduced the capability to perform full hierarchical data processing with its introduction of the LEFT Outer Join operation. This natural hierarchical processing capability will be explained in this article.

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Oracle on Windows / .NET ??(2010?12?)

- by Yusuke.Yamamoto

Oracle Database ? Windows Server / .NET ???????????????????????????????????????? 12?~1???????????????? Oracle on Windows / .NET ???????????????! ???????????????????? ?? ????? Windows Server / .NET ???????? Oracle Database ? Windows Server Oracle Database ? .NET Oracle on Windows / .NET ?????? ????? Windows Server / .NET ???????? Oracle=Linux / UNIX ?? ?Oracle Database ????? Linux / UNIX ?????????????????????? ???????? Windows RDBMS ?????????????????? Oracle on Windows ???No.1???!2,000???????! ????????????????????????????????????????????????? ???????????????? Windows ???????&?????????!? ?????????Windows Server ?????????UNIX ? Oracle Database ?????????????????????????(????????·??????)? ????Windows Server ???(Active Directory, MSCS, VSS, etc)????????????????????? ????????1????!Windows Server 2008??Oracle Database 11g???????? ???.NET ??????????????????????? Oracle Data Provider for .NET ????????Oracle Database ???·?????????????????????? ???????/???1????!.NET + Oracle Database 11g ???????????? Oracle Database ? Windows Server / .NET ?????????????????????????? Oracle on Windows / .NET ????????·Tips??????????????! Oracle Database ? Windows Server Windows ?????? Oracle Database 11g Release 2 ??????|????????????????????! Oracle Database 11g Release 2 ????? ???:??????|??????|???????? OTN Windows Server System Center Windows ? Oracle Database ??? " ?????????????? SQL Server ????? / SQL Server ?????? ???!?SQL Server????????????????(??) SQL Server ?? Oracle Database ????????????? ??? SQL Server ??????????????????????????????????? " ?????????????? Oracle Database ? .NET .NET ?????? Oracle Data Access Components(ODAC) ??????|????????????????????! .NET and Windows Application Development ????? ???:.NET??? OTN .NET Developer Center .NET ? Oracle Database ??????????? " ?????????????? Visual Studio ?? Oracle Database ?????????? " ?????????????? Oracle on Windows / .NET ?????? ???????????????????? ????(Oracle Direct Seminar)????????????????????????????????????????? ??????????? View RSS feed ?????

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Symbian sort un kit d'outils pour les développeurs d'application sous Symbian^3, simple d'utilisatio

Mise à jour du 03.05.2010 par Katleen Symbian sort un kit d'outils pour les développeurs d'application sous Symbian^3, simple d'utilisation et compatible Windows, Mac et Linux « Si vous savez créer une page web, vous êtes un développeur Symbian^3 ». Le nouveau slogan de Symbian destiné à promouvoir ses derniers outils de développement d'applications tout juste disponibles pour Windows, Mac et Linux est on ne peut plus clair. Leur maniement sera facile. L'écriture se fera en HTML, CSS et JavaScript. De plus, des API JavaScript spécifiques permettront de travailler sur des fonctions particulières telles que le répertoire, l'appareil photo, l'accéléromètre, le GPS, etc.

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System.Data.SQLite

- by csharp-source.net

System.Data.SQLite is an enhanced version of the original SQLite database engine. It is a complete drop-in replacement for the original sqlite3.dll (you can even rename it to sqlite3.dll). It has no linker dependency on the .NET runtime so it can be distributed independently of .NET, yet embedded in the binary is a complete ADO.NET 2.0 provider for full managed development.

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Distributed database technologies to share data between database systems

This article is intended to illustrate the main concepts of distributed database technologies supporting the replication principles in order to share data among different database systems.

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google-chrome video application association

- by Ben Lee

Is there any way to tell google-chrome to launch video files of particular types in an external application (or even just to bring up the download box as if the type was un-handled), instead of showing the video inside the browser? Searching online, it seems that chrome is supposed to use xdg-mime for file associations, but apparently is ignoring this for video. For example, when I do: xdg-mime query default video/mpeg It returns dragonplayer.desktop. But when I click on a mpeg video link, chrome displays it internally instead of launching Dragon Player (if I double click on a mpeg file in my file manager, on the other hand, it does open Dragon Player). So is there a way to tell chrome to respect this setting, or another way to coax chrome into opening the file externally? If it matters, I'm running the latest version of google-chrome stable (not chromium) at the time of writing, v. 18.0.1025.151, on kubuntu 11.10.

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Looking for enterprise web application design inspiration [closed]

- by Farshid

I've checked many websites to be inspired about what the look and feel of a serious enterprise web-application should look like. But the whole I saw were designed for being used by single users and not serious corporate users. The designs I saw were mostly happy-colored, and looked like being developed by a small team of eager young passionate developers. But what I'm looking for, are showcases of serious web apps' designs (e.g. web apps developed by large corporations) that are developed for being used by a large number of corporate uses. Can you suggest me sources for this kind of inspiration?

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Application to display battery info

- by Nik

First of all, I am not sure the title of this question is the most appropriate however this is what I meant to say, There are many ways to extend the life of a laptop battery. One way is by not connecting it to the AC adapter all the time which will overcharge it. I read that in this website. Is there an application which automatically prevents the charging of the battery once it has reached 80% charged? I mean that is such a cool feature. Sometimes people tend to forget to remove the AC adapter and this could diminish the capacity and reduce the life time of the battery. Does the battery indicator in ubuntu display info or pop-up when the battery is almost dead (dead not in the sense of usage time) but rather a degraded battery?

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Oracle ETPM v2.3.1 Examachine Performance Benchmark Data Sheet

- by Paula Speranza-Hadley

Oracle Tax is pleased to announce the exceptional results of the Oracle ETPM v2.3.1 Examachine performance benchmark. The benchmark achieved the following results: · Processed8M outpayments and 2M payments in 6 hours · Processed 1M forms in 4 hours · Near linear scalability of batch processing For the complete data sheet, please click on the following link: https://blogs.oracle.com/tax/resource/OracleETPMv231ExamachinePerformanceBenchmarkDataSheet.pdf

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Data Quality Services Performance Best Practices Guide

This guide details high-level performance numbers expected and a set of best practices on getting optimal performance when using Data Quality Services (DQS) in SQL Server 2012 with Cumulative Update 1. Schedule Azure backupsRed Gate’s Cloud Services makes it simple to create and schedule backups of your SQL Azure databases to Azure blob storage or Amazon S3. Try it for free today.

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Using Entity Framework Entity splitting customisations in an ASP.Net application

- by nikolaosk

I have been teaching in the past few weeks many people on how to use Entity Framework. I have decided to provide some of the samples I am using in my classes. First let’s try to define what EF is and why it is going to help us to create easily data-centric applications.Entity Framework is an object-relational mapping (ORM) framework for the .NET Framework.EF addresses the problem of Object-relational impedance mismatch . I will not be talking about that mismatch because it is well documented in many...(read more)

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Fonts look horrible in any java application

- by Eirik Berg

All fonts in java applications look horrible. I have seen a few questions about this previously, but they are quite old now(11.04 was the most recent, but that didn't seem to be the same problem). For some reason java applications do not use the system font (Ubuntu 11), but rather some elongated font that doesn't seem to have any anti-aliasing. So what I'm asking is if this is an open bug(couldn't find any on launchpad), something the developers have done wrong, or if there is a way to configure the fonts used in java application. Perhaps this is just a shortcoming of openjdk and I should install the Sun version instead? Attached an image showing jitsi, but the problem is also present in minecraft, my internet-bank and anything else involving java. I'm on 12.04, but since I couldn't find anything on launchpad I'm assuming that isn't relevant. Edit: actually managed to forget the picture... Thanks!

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Direct3D9 application won't write to depth buffer

- by DeadMG

I've got an application written in D3D9 which will not write any values to the depth buffer, resulting in incorrect values for the depth test. Things I've checked so far: D3DRS_ZENABLE, set to TRUE D3DRS_ZWRITEENABLE, set to TRUE D3DRS_ZFUNC, set to D3DCMP_LESSEQUAL The depth buffer is definitely bound to the pipeline at the relevant time The depth buffer was correctly cleared before use. I've used PIX to confirm that all of these things occurred as expected. For example, if I clear the depth buffer to 0 instead of 1, then correctly nothing is drawn, and PIX confirms that all the pixels failed the depth test. But I've also used PIX to confirm that my submitted geometry does not write to the depth buffer and so is not correctly rendered. Any other suggestions?

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July SQL Server UG Event in Manchester

I will be speaking at the SQL Server UK User Group event in Manchester on 16.07.2009. I am going to be talking about data mining again and how it isn’t all statistics and people with PhDs from Oxford. Come join me and the excellent Chris Testa-O’Neill. More details and registration can be found here

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Oracle VM Templates Enable Oracle Real Application Clusters Deployment Up to 10 Times Faster than VMware vSphere

- by Angela Poth

Oracle VM - Quantifying the Value of Application-Driven DeploymentThe recently published report by the Evaluator Group, “Oracle VM – Quantifying The Value of Application-Driven Virtualization,“ validates Oracle’s ease of use and time savings over VMware vSphere 5. The report found that users can deploy Oracle Real Application Clusters up to 10 times faster with Oracle VM templates than VMware vSphere. Using Oracle VM templates users can deploy E-Business Suites nearly 7 times faster than VMware vSphere."Oracle VM’s application-driven architecture was built to enable rapid deployment of enterprise applications, with simplified integrated lifecycle management, to fully support Oracle applications. Our testing has demonstrated 90 percent improvement deploying Oracle Real Application Clusters 11g R2 using Oracle VM Templates and a similar improvement of 85 percent for the Oracle E-Business Suite 12.1.1. This clearly shows that Templates can provide real value to customers and should become an essential component for enabling rapid enterprise application deployment and management," said Leah Schoeb, Senior Partner, Evaluator Group.Read the Press Release Get a copy of the Evaluator Group Report: Oracle VM – Quantifying The Value of Application-Driven Virtualization

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Prevent anonymous access to form and application pages in SharePoint 2010

- by shehan

When you create a Publishing site that has anonymous access enabled, you will notice that anonymous users will not be able to access pages that reside in the “_layouts” virtual directory (e.g. http://siteX/_layouts/viewlsts.aspx). This is because the publishing infrastructure activates a hidden feature that prevents anonymous users from accessing these types of pages. However, if you were to create a site collection based of Blank Site Template, you would notice that these pages are accessible by anonymous users. The fix is quite simple. There is a hidden feature that you would need to manually activate via stsadm. The feature is called “ViewFormPagesLockDown” (and is available in the Features folders in the 14 hive) To activate it: stsadm -o activatefeature -filename ViewFormPagesLockDown\feature.xml -url http://ServerName Once activated anonymous users will be promoted to enter credentials when they try to access form and application pages. The feature can also be deactivated for publishing sites that have it automatically turned on. Technorati Tags: SharePoint 2010,anonymous,lockdown,pages,security

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Looking for enterprise web application design inspiration

- by Farshid

I've checked many websites to be inspired about what the look and feel of a serious enterprise web-application should look like. But the whole I saw were designed for being used by single users and not serious corporate users. The designs I saw were mostly happy-colored, and looked like being developed by a small team of eager young passionate developers. But what I'm looking for, are showcases of serious web apps' designs (e.g. web apps developed by large corporations) that are developed for being used by a large number of corporate uses. Can you suggest me sources for this kind of inspiration?

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Stairway to XML: Level 8 - Deleting Data from an XML Instance

in order to use the modify() method to delete data from typed and untyped XML instances, you must pass an XML DML expression as an argument to the method. That expression must include the delete keyword, along with an XQuery expression that defines the XML component to be deleted. Robert makes it seem simple, as usual. The best way to version control T-SQLSSMS plug-in SQL Source Control connects SVN, TFS, Git, Hg and all others to SQL Server. Learn more.

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Best practice to propagate preferences of application

- by Shebuka

What is your approach with propagation to all classes/windows of preferences/settings of your application? Do you share the preference_manager class to all classes/windows who need it or you make variables in each classes/windows and update them manually each time setting are changed? Currently I have a PreferencesInterface class that hold all preferences and is responsible to default all values with a dedicated method called on create and when needed, all values are public, so non getters/setters, also it have virtual SavePreferences/LoadPreferences methods. Then I have PreferencesManager that extends from PreferencesInterface and is responsible for actually implementation of SavePreferences/LoadPreferences. I've made this basically for cross-platform so that every platform can have a different implementation of actual storage (registry, ini, plist, xml, whatever).

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HDWF [was OHDF]

- by Glen McCallum

Acronyms, acronyms ... same name (Oracle Healthcare Data Warehouse Foundation). Now it goes by HDWF. Don't ask me why. HDWF Version 2.0 was released quietly on 12 May. I'm told it is available on eDelivery. I've been spending more time working on HDWF this month. There's no question Oracle is moving at full-steam on this one. I've even spent a few nights this week working on India time with the team over there. We're busy moving Oracle's Operating Room Analytics application onto the new HDWF enterprise healthcare model. It's really been a great illustration of the comprehensiveness of the model. It was easily able accomodate all of the information required by ORA downstream.

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Using the ASP.NET Cache to cache data in a Model or Business Object layer, without a dependency on System.Web in the layer - Part One.

- by Rhames

ASP.NET applications can make use of the System.Web.Caching.Cache object to cache data and prevent repeated expensive calls to a database or other store. However, ideally an application should make use of caching at the point where data is retrieved from the database, which typically is inside a Business Objects or Model layer. One of the key features of using a UI pattern such as Model-View-Presenter (MVP) or Model-View-Controller (MVC) is that the Model and Presenter (or Controller) layers are developed without any knowledge of the UI layer. Introducing a dependency on System.Web into the Model layer would break this independence of the Model from the View. This article gives a solution to this problem, using dependency injection to inject the caching implementation into the Model layer at runtime. This allows caching to be used within the Model layer, without any knowledge of the actual caching mechanism that will be used. Create a sample application to use the caching solution Create a test SQL Server database This solution uses a SQL Server database with the same Sales data used in my previous post on calculating running totals. The advantage of using this data is that it gives nice slow queries that will exaggerate the effect of using caching! To create the data, first create a new SQL database called CacheSample. Next run the following script to create the Sale table and populate it: USE CacheSample GO CREATE TABLE Sale(DayCount smallint, Sales money) CREATE CLUSTERED INDEX ndx_DayCount ON Sale(DayCount) go INSERT Sale VALUES (1,120) INSERT Sale VALUES (2,60) INSERT Sale VALUES (3,125) INSERT Sale VALUES (4,40) DECLARE @DayCount smallint, @Sales money SET @DayCount = 5 SET @Sales = 10 WHILE @DayCount < 5000 BEGIN INSERT Sale VALUES (@DayCount,@Sales) SET @DayCount = @DayCount + 1 SET @Sales = @Sales + 15 END Next create a stored procedure to calculate the running total, and return a specified number of rows from the Sale table, using the following script: USE [CacheSample] GO SET ANSI_NULLS ON GO SET QUOTED_IDENTIFIER ON GO -- ============================================= -- Author: Robin -- Create date: -- Description: -- ============================================= CREATE PROCEDURE [dbo].[spGetRunningTotals] -- Add the parameters for the stored procedure here @HighestDayCount smallint = null AS BEGIN -- SET NOCOUNT ON added to prevent extra result sets from -- interfering with SELECT statements. SET NOCOUNT ON; IF @HighestDayCount IS NULL SELECT @HighestDayCount = MAX(DayCount) FROM dbo.Sale DECLARE @SaleTbl TABLE (DayCount smallint, Sales money, RunningTotal money) DECLARE @DayCount smallint, @Sales money, @RunningTotal money SET @RunningTotal = 0 SET @DayCount = 0 DECLARE rt_cursor CURSOR FOR SELECT DayCount, Sales FROM Sale ORDER BY DayCount OPEN rt_cursor FETCH NEXT FROM rt_cursor INTO @DayCount,@Sales WHILE @@FETCH_STATUS = 0 AND @DayCount <= @HighestDayCount BEGIN SET @RunningTotal = @RunningTotal + @Sales INSERT @SaleTbl VALUES (@DayCount,@Sales,@RunningTotal) FETCH NEXT FROM rt_cursor INTO @DayCount,@Sales END CLOSE rt_cursor DEALLOCATE rt_cursor SELECT DayCount, Sales, RunningTotal FROM @SaleTbl END GO Create the Sample ASP.NET application In Visual Studio create a new solution and add a class library project called CacheSample.BusinessObjects and an ASP.NET web application called CacheSample.UI. The CacheSample.BusinessObjects project will contain a single class to represent a Sale data item, with all the code to retrieve the sales from the database included in it for simplicity (normally I would at least have a separate Repository or other object that is responsible for retrieving data, and probably a data access layer as well, but for this sample I want to keep it simple). The C# code for the Sale class is shown below: using System; using System.Collections.Generic; using System.Data; using System.Data.SqlClient; namespace CacheSample.BusinessObjects { public class Sale { public Int16 DayCount { get; set; } public decimal Sales { get; set; } public decimal RunningTotal { get; set; } public static IEnumerable<Sale> GetSales(int? highestDayCount) { List<Sale> sales = new List<Sale>(); SqlParameter highestDayCountParameter = new SqlParameter("@HighestDayCount", SqlDbType.SmallInt); if (highestDayCount.HasValue) highestDayCountParameter.Value = highestDayCount; else highestDayCountParameter.Value = DBNull.Value; string connectionStr = System.Configuration.ConfigurationManager .ConnectionStrings["CacheSample"].ConnectionString; using(SqlConnection sqlConn = new SqlConnection(connectionStr)) using (SqlCommand sqlCmd = sqlConn.CreateCommand()) { sqlCmd.CommandText = "spGetRunningTotals"; sqlCmd.CommandType = CommandType.StoredProcedure; sqlCmd.Parameters.Add(highestDayCountParameter); sqlConn.Open(); using (SqlDataReader dr = sqlCmd.ExecuteReader()) { while (dr.Read()) { Sale newSale = new Sale(); newSale.DayCount = dr.GetInt16(0); newSale.Sales = dr.GetDecimal(1); newSale.RunningTotal = dr.GetDecimal(2); sales.Add(newSale); } } } return sales; } } } The static GetSale() method makes a call to the spGetRunningTotals stored procedure and then reads each row from the returned SqlDataReader into an instance of the Sale class, it then returns a List of the Sale objects, as IEnnumerable<Sale>. A reference to System.Configuration needs to be added to the CacheSample.BusinessObjects project so that the connection string can be read from the web.config file. In the CacheSample.UI ASP.NET project, create a single web page called ShowSales.aspx, and make this the default start up page. This page will contain a single button to call the GetSales() method and a label to display the results. The html mark up and the C# code behind are shown below: ShowSales.aspx <%@ Page Language="C#" AutoEventWireup="true" CodeBehind="ShowSales.aspx.cs" Inherits="CacheSample.UI.ShowSales" %> <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html xmlns="http://www.w3.org/1999/xhtml"> <head runat="server"> <title>Cache Sample - Show All Sales</title> </head> <body> <form id="form1" runat="server"> <div> <asp:Button ID="btnTest1" runat="server" onclick="btnTest1_Click" Text="Get All Sales" />     <asp:Label ID="lblResults" runat="server"></asp:Label> </div> </form> </body> </html> ShowSales.aspx.cs using System; using System.Collections.Generic; using System.Linq; using System.Web; using System.Web.UI; using System.Web.UI.WebControls; using CacheSample.BusinessObjects; namespace CacheSample.UI { public partial class ShowSales : System.Web.UI.Page { protected void Page_Load(object sender, EventArgs e) { } protected void btnTest1_Click(object sender, EventArgs e) { System.Diagnostics.Stopwatch stopWatch = new System.Diagnostics.Stopwatch(); stopWatch.Start(); var sales = Sale.GetSales(null); var lastSales = sales.Last(); stopWatch.Stop(); lblResults.Text = string.Format( "Count of Sales: {0}, Last DayCount: {1}, Total Sales: {2}. Query took {3} ms", sales.Count(), lastSales.DayCount, lastSales.RunningTotal, stopWatch.ElapsedMilliseconds); } } } Finally we need to add a connection string to the CacheSample SQL Server database, called CacheSample, to the web.config file: <?xmlversion="1.0"?> <configuration> <connectionStrings> <addname="CacheSample" connectionString="data source=.\SQLEXPRESS;Integrated Security=SSPI;Initial Catalog=CacheSample" providerName="System.Data.SqlClient" /> </connectionStrings> <system.web> <compilationdebug="true"targetFramework="4.0" /> </system.web> </configuration> Run the application and click the button a few times to see how long each call to the database takes. On my system, each query takes about 450ms. Next I shall look at a solution to use the ASP.NET caching to cache the data returned by the query, so that subsequent requests to the GetSales() method are much faster. Adding Data Caching Support I am going to create my caching support in a separate project called CacheSample.Caching, so the next step is to add a class library to the solution. We shall be using the application configuration to define the implementation of our caching system, so we need a reference to System.Configuration adding to the project. ICacheProvider<T> Interface The first step in adding caching to our application is to define an interface, called ICacheProvider, in the CacheSample.Caching project, with methods to retrieve any data from the cache or to retrieve the data from the data source if it is not present in the cache. Dependency Injection will then be used to inject an implementation of this interface at runtime, allowing the users of the interface (i.e. the CacheSample.BusinessObjects project) to be completely unaware of how the caching is actually implemented. As data of any type maybe retrieved from the data source, it makes sense to use generics in the interface, with a generic type parameter defining the data type associated with a particular instance of the cache interface implementation. The C# code for the ICacheProvider interface is shown below: using System; using System.Collections.Generic; namespace CacheSample.Caching { public interface ICacheProvider { } public interface ICacheProvider<T> : ICacheProvider { T Fetch(string key, Func<T> retrieveData, DateTime? absoluteExpiry, TimeSpan? relativeExpiry); IEnumerable<T> Fetch(string key, Func<IEnumerable<T>> retrieveData, DateTime? absoluteExpiry, TimeSpan? relativeExpiry); } } The empty non-generic interface will be used as a type in a Dictionary generic collection later to store instances of the ICacheProvider<T> implementation for reuse, I prefer to use a base interface when doing this, as I think the alternative of using object makes for less clear code. The ICacheProvider<T> interface defines two overloaded Fetch methods, the difference between these is that one will return a single instance of the type T and the other will return an IEnumerable<T>, providing support for easy caching of collections of data items. Both methods will take a key parameter, which will uniquely identify the cached data, a delegate of type Func<T> or Func<IEnumerable<T>> which will provide the code to retrieve the data from the store if it is not present in the cache, and absolute or relative expiry policies to define when a cached item should expire. Note that at present there is no support for cache dependencies, but I shall be showing a method of adding this in part two of this article. CacheProviderFactory Class We need a mechanism of creating instances of our ICacheProvider<T> interface, using Dependency Injection to get the implementation of the interface. To do this we shall create a CacheProviderFactory static class in the CacheSample.Caching project. This factory will provide a generic static method called GetCacheProvider<T>(), which shall return instances of ICacheProvider<T>. We can then call this factory method with the relevant data type (for example the Sale class in the CacheSample.BusinessObject project) to get a instance of ICacheProvider for that type (e.g. call CacheProviderFactory.GetCacheProvider<Sale>() to get the ICacheProvider<Sale> implementation). The C# code for the CacheProviderFactory is shown below: using System; using System.Collections.Generic; using CacheSample.Caching.Configuration; namespace CacheSample.Caching { public static class CacheProviderFactory { private static Dictionary<Type, ICacheProvider> cacheProviders = new Dictionary<Type, ICacheProvider>(); private static object syncRoot = new object(); ///<summary> /// Factory method to create or retrieve an implementation of the /// ICacheProvider interface for type <typeparamref name="T"/>. ///</summary> ///<typeparam name="T"> /// The type that this cache provider instance will work with ///</typeparam> ///<returns>An instance of the implementation of ICacheProvider for type ///<typeparamref name="T"/>, as specified by the application /// configuration</returns> public static ICacheProvider<T> GetCacheProvider<T>() { ICacheProvider<T> cacheProvider = null; // Get the Type reference for the type parameter T Type typeOfT = typeof(T); // Lock the access to the cacheProviders dictionary // so multiple threads can work with it lock (syncRoot) { // First check if an instance of the ICacheProvider implementation // already exists in the cacheProviders dictionary for the type T if (cacheProviders.ContainsKey(typeOfT)) cacheProvider = (ICacheProvider<T>)cacheProviders[typeOfT]; else { // There is not already an instance of the ICacheProvider in // cacheProviders for the type T // so we need to create one // Get the Type reference for the application's implementation of // ICacheProvider from the configuration Type cacheProviderType = Type.GetType(CacheProviderConfigurationSection.Current. CacheProviderType); if (cacheProviderType != null) { // Now get a Type reference for the Cache Provider with the // type T generic parameter Type typeOfCacheProviderTypeForT = cacheProviderType.MakeGenericType(new Type[] { typeOfT }); if (typeOfCacheProviderTypeForT != null) { // Create the instance of the Cache Provider and add it to // the cacheProviders dictionary for future use cacheProvider = (ICacheProvider<T>)Activator. CreateInstance(typeOfCacheProviderTypeForT); cacheProviders.Add(typeOfT, cacheProvider); } } } } return cacheProvider; } } } As this code uses Activator.CreateInstance() to create instances of the ICacheProvider<T> implementation, which is a slow process, the factory class maintains a Dictionary of the previously created instances so that a cache provider needs to be created only once for each type. The type of the implementation of ICacheProvider<T> is read from a custom configuration section in the application configuration file, via the CacheProviderConfigurationSection class, which is described below. CacheProviderConfigurationSection Class The implementation of ICacheProvider<T> will be specified in a custom configuration section in the application’s configuration. To handle this create a folder in the CacheSample.Caching project called Configuration, and add a class called CacheProviderConfigurationSection to this folder. This class will extend the System.Configuration.ConfigurationSection class, and will contain a single string property called CacheProviderType. The C# code for this class is shown below: using System; using System.Configuration; namespace CacheSample.Caching.Configuration { internal class CacheProviderConfigurationSection : ConfigurationSection { public static CacheProviderConfigurationSection Current { get { return (CacheProviderConfigurationSection) ConfigurationManager.GetSection("cacheProvider"); } } [ConfigurationProperty("type", IsRequired=true)] public string CacheProviderType { get { return (string)this["type"]; } } } } Adding Data Caching to the Sales Class We now have enough code in place to add caching to the GetSales() method in the CacheSample.BusinessObjects.Sale class, even though we do not yet have an implementation of the ICacheProvider<T> interface. We need to add a reference to the CacheSample.Caching project to CacheSample.BusinessObjects so that we can use the ICacheProvider<T> interface within the GetSales() method. Once the reference is added, we can first create a unique string key based on the method name and the parameter value, so that the same cache key is used for repeated calls to the method with the same parameter values. Then we get an instance of the cache provider for the Sales type, using the CacheProviderFactory, and pass the existing code to retrieve the data from the database as the retrievalMethod delegate in a call to the Cache Provider Fetch() method. The C# code for the modified GetSales() method is shown below: public static IEnumerable<Sale> GetSales(int? highestDayCount) { string cacheKey = string.Format("CacheSample.BusinessObjects.GetSalesWithCache({0})", highestDayCount); return CacheSample.Caching.CacheProviderFactory. GetCacheProvider<Sale>().Fetch(cacheKey, delegate() { List<Sale> sales = new List<Sale>(); SqlParameter highestDayCountParameter = new SqlParameter("@HighestDayCount", SqlDbType.SmallInt); if (highestDayCount.HasValue) highestDayCountParameter.Value = highestDayCount; else highestDayCountParameter.Value = DBNull.Value; string connectionStr = System.Configuration.ConfigurationManager. ConnectionStrings["CacheSample"].ConnectionString; using (SqlConnection sqlConn = new SqlConnection(connectionStr)) using (SqlCommand sqlCmd = sqlConn.CreateCommand()) { sqlCmd.CommandText = "spGetRunningTotals"; sqlCmd.CommandType = CommandType.StoredProcedure; sqlCmd.Parameters.Add(highestDayCountParameter); sqlConn.Open(); using (SqlDataReader dr = sqlCmd.ExecuteReader()) { while (dr.Read()) { Sale newSale = new Sale(); newSale.DayCount = dr.GetInt16(0); newSale.Sales = dr.GetDecimal(1); newSale.RunningTotal = dr.GetDecimal(2); sales.Add(newSale); } } } return sales; }, null, new TimeSpan(0, 10, 0)); } This example passes the code to retrieve the Sales data from the database to the Cache Provider as an anonymous method, however it could also be written as a lambda. The main advantage of using an anonymous function (method or lambda) is that the code inside the anonymous function can access the parameters passed to the GetSales() method. Finally the absolute expiry is set to null, and the relative expiry set to 10 minutes, to indicate that the cache entry should be removed 10 minutes after the last request for the data. As the ICacheProvider<T> has a Fetch() method that returns IEnumerable<T>, we can simply return the results of the Fetch() method to the caller of the GetSales() method. This should be all that is needed for the GetSales() method to now retrieve data from a cache after the first time the data has be retrieved from the database. Implementing a ASP.NET Cache Provider The final step is to actually implement the ICacheProvider<T> interface, and add the implementation details to the web.config file for the dependency injection. The cache provider implementation needs to have access to System.Web. Therefore it could be placed in the CacheSample.UI project, or in its own project that has a reference to System.Web. Implementing the Cache Provider in a separate project is my favoured approach. Create a new project inside the solution called CacheSample.CacheProvider, and add references to System.Web and CacheSample.Caching to this project. Add a class to the project called AspNetCacheProvider. Make the class a generic class by adding the generic parameter <T> and indicate that the class implements ICacheProvider<T>. The C# code for the AspNetCacheProvider class is shown below: using System; using System.Collections.Generic; using System.Linq; using System.Web; using System.Web.Caching; using CacheSample.Caching; namespace CacheSample.CacheProvider { public class AspNetCacheProvider<T> : ICacheProvider<T> { #region ICacheProvider<T> Members public T Fetch(string key, Func<T> retrieveData, DateTime? absoluteExpiry, TimeSpan? relativeExpiry) { return FetchAndCache<T>(key, retrieveData, absoluteExpiry, relativeExpiry); } public IEnumerable<T> Fetch(string key, Func<IEnumerable<T>> retrieveData, DateTime? absoluteExpiry, TimeSpan? relativeExpiry) { return FetchAndCache<IEnumerable<T>>(key, retrieveData, absoluteExpiry, relativeExpiry); } #endregion #region Helper Methods private U FetchAndCache<U>(string key, Func<U> retrieveData, DateTime? absoluteExpiry, TimeSpan? relativeExpiry) { U value; if (!TryGetValue<U>(key, out value)) { value = retrieveData(); if (!absoluteExpiry.HasValue) absoluteExpiry = Cache.NoAbsoluteExpiration; if (!relativeExpiry.HasValue) relativeExpiry = Cache.NoSlidingExpiration; HttpContext.Current.Cache.Insert(key, value, null, absoluteExpiry.Value, relativeExpiry.Value); } return value; } private bool TryGetValue<U>(string key, out U value) { object cachedValue = HttpContext.Current.Cache.Get(key); if (cachedValue == null) { value = default(U); return false; } else { try { value = (U)cachedValue; return true; } catch { value = default(U); return false; } } } #endregion } } The two interface Fetch() methods call a private method called FetchAndCache(). This method first checks for a element in the HttpContext.Current.Cache with the specified cache key, and if so tries to cast this to the specified type (either T or IEnumerable<T>). If the cached element is found, the FetchAndCache() method simply returns it. If it is not found in the cache, the method calls the retrievalMethod delegate to get the data from the data source, and then adds this to the HttpContext.Current.Cache. The final step is to add the AspNetCacheProvider class to the relevant custom configuration section in the CacheSample.UI.Web.Config file. To do this there needs to be a <configSections> element added as the first element in <configuration>. This will match a custom section called <cacheProvider> with the CacheProviderConfigurationSection. Then we add a <cacheProvider> element, with a type property set to the fully qualified assembly name of the AspNetCacheProvider class, as shown below: <?xmlversion="1.0"?> <configuration> <configSections> <sectionname="cacheProvider" type="CacheSample.Base.Configuration.CacheProviderConfigurationSection, CacheSample.Base" /> </configSections> <connectionStrings> <addname="CacheSample" connectionString="data source=.\SQLEXPRESS;Integrated Security=SSPI;Initial Catalog=CacheSample" providerName="System.Data.SqlClient" /> </connectionStrings> <cacheProvidertype="CacheSample.CacheProvider.AspNetCacheProvider`1, CacheSample.CacheProvider, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null"> </cacheProvider> <system.web> <compilationdebug="true"targetFramework="4.0" /> </system.web> </configuration> One point to note is that the fully qualified assembly name of the AspNetCacheProvider class includes the notation `1 after the class name, which indicates that it is a generic class with a single generic type parameter. The CacheSample.UI project needs to have references added to CacheSample.Caching and CacheSample.CacheProvider so that the actual application is aware of the relevant cache provider implementation. Conclusion After implementing this solution, you should have a working cache provider mechanism, that will allow the middle and data access layers to implement caching support when retrieving data, without any knowledge of the actually caching implementation. If the UI is not ASP.NET based, if for example it is Winforms or WPF, the implementation of ICacheProvider<T> would be written around whatever technology is available. It could even be a standalone caching system that takes full responsibility for adding and removing items from a global store. The next part of this article will show how this caching mechanism may be extended to provide support for cache dependencies, such as the System.Web.Caching.SqlCacheDependency. Another possible extension would be to cache the cache provider implementations instead of storing them in a static Dictionary in the CacheProviderFactory. This would prevent a build up of seldom used cache providers in the application memory, as they could be removed from the cache if not used often enough, although in reality there are probably unlikely to be vast numbers of cache provider implementation instances, as most applications do not have a massive number of business object or model types.

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Reviewing Orace ADF Enterprise Application Development Made Simple Book

- by Grant Ronald

Although I was a technical reviewer of Oracle ADF Enterprise Application Development-Made Simple (by Sten Vesterli) it is nice to get the finished article in your hands as a real tangible book. Personally, on a sun lounger with a Dan Brown book I can read 300 pages a day, but technical books are a different beast and I find it hard to get through them with the same vigour. However, I'm up to chapter 7 in Sten's book and so far it's holding my interest. He writes in an almost conversational tone and I really like the comparisons to "real world" concepts - like page templates being like gingerbread cookie cutters. Personally I like to be able to compare or size up a new concept against something I already know. I'll post a full review next week but the good news is 212 pages in and I'm still reading!

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Web application Project management methodologie

- by dutchiexl

I am looking to streamline my company's web development process. Including analysis. I myself am specialized in XP and Scrum. But we are building web application with a process cycle of 3-4 weeks and a lifetime of 1-4 months. When a project is sold, only then the project managers (= people who do analysis but know nothing about it = a small flow chart and some screen shots as analysis) What is happening is: A LOT of change requests Minimal development time Minimal analysis time NOW: the main question :) can you recommend me some methodologies and books to read for the entire project management ? Thanks in advance @Edit, I myself was looking at a combination of SCRUM for the management with flowcharts, + RAD/LD for development, and trying to distilate something from that.

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