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  • Rails Plugin for Multiple Ratings Per Model?

    - by Kevin
    I'm looking to add the capability of rating a model I have under several different categories like "Knowledgeable" "Organized", etc. Is there a plugin that will allow me to do this, and maybe even have a cool x/5 stars graphical representation as well?

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  • C# Library to Generate UML Diagrams

    - by Carlos Garces
    Hi! My project actually use XML files to define flow of the application. I like to convert this XML a image that represent the flow, to use it in the documentation. There is any c# library that help with the graphical part of a UML generation? There is any XML standart format to generate UML flows that can be converted to IMG? I need something like this http://en.wikipedia.org/wiki/File:LampFlowchart.svg

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  • iPhone XML SOAP requests or .NET Web Services

    - by CocoaNewBee
    I've been trying to to consume SOAP requests (.NET web services) and have found some pretty good tools that I wanted to share: 1) http://grabalife.com/2009/10/19/using-net-web-services-and-dataset-objects-in-your-iphone-app/ Really easy clean way to perform all the call needed for consuming the services. 2) http://code.google.com/p/mac-soapclient/ SOAP Client uses WSDL files you provide to dynamically create a graphical user interface for any given SOAP-based web service Hopefully that will help someone as much as me!!! Happy coding !

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  • Tutorials (example) C# step by step

    - by user348173
    Hi. Does anyone know a good C# tutorials (example) step by step? It should be not a description of libraries, foundations and the OOP concept, and so forth, but the writing of any application step by step. For example, a mail client, telephone directory, a simple graphical editor, audio player. Thanks!

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  • install avisynth under linux via ssh

    - by Issak
    i have a linux server (ubuntu os) to which i have access via ssh and wish to install avisynth on it. i know windows apps can be installed with the help of wine, but the problem is how i manage to install the app (avisynth) thru ssh, that is, without graphical intarface? can wine be somehow configured to manage such a case? what should i do to install avisynth via ssh? (am not insterested in other apps)

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  • GUI/TUI linux library

    - by Penz
    Is there any UI library that can be to build both a text user interface (ncurses) and graphical user interface (GTK? QT?) from the same source? I know that debconf can be used with various frontends, I would like to build something similar but programmable.

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  • Icons in dired in Emacs (on Mac or Linux)

    - by Dave
    I'd like to have dired show a little icon next to each file, similar to what you'd see in "list" or "details" view on a graphical file browser. Someone posted a similar question but the only answer was for Windows only; I want to be able to do this on Linux or Mac.

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  • CSS Print Style Sheets - Examples

    - by bsreekanth
    Trying to learn about how to effectively use print.css, so that graphical and navigational elements are not shown in print preview/print. Read some articles, and part of print css of html5 boilerplate. Two sites, which was quite impressive the way they change the look during print are http://css-tricks.com/ http://bottlerocketcreative.com/ But I cannot see the css related to print. Can you please point to the css they use to learn how to do similar transformation. thanks.

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  • Is there any small linux distribution which comes with a complete C devleopment environment

    - by hits_lucky
    Hi, I have installed "Damn Small Linux" on my home computer for doing C development in unix. But the distribution doesn't by default come with the C development environment and I am facing some issues when trying to install the gcc. Is there any other small Linux distribution which by default has the required packages for the C development. And also I don't want additional software which takes up lot of space but still would like to have the graphical environment. Thanks

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  • graphs and charts on the iPhone

    - by Jon
    My client has requested data to be presented in a graphical format on the iPhone (a pie chart or something similar). I am wondering how others have handled this - A.) deliver the raw data to the phone and somehow build the chart on the phone, or B.) have the back-end services build the chart and deliver it (png format) to the phone? Thanks for any advice.

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  • Bind Java program to Cocoa interface

    - by Kevin
    Hi, would it be possible to bind a Java application to a Cocoa graphical interface? I'm working in Eclipse right now, on my mac, and am wondering if Interface Builder could be used to construct a new interface so that I don't have to look at Swing all day. Any ideas/suggestions? Thanks!

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  • I need to model my Javascript application

    - by Totty
    Hy, I was looking for a software to model an application, because is becoming too big. Like this: Class - A Methods - a, b, c, d, e Class - B Methods - a, b, c, d, e This should be in graphical mode, Classes are some boxes, and the methods are in the box. Then I would like to be able to make a arrow from one method to another. Do you know some good software? thanks

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  • Is there any small linux distribution which comes with a complete C development environment

    - by hits_lucky
    Hi, I have installed "Damn Small Linux" on my home computer for doing C development in unix. But the distribution doesn't by default come with the C development environment and I am facing some issues when trying to install the gcc. Is there any other small Linux distribution which by default has the required packages for the C development. And also I don't want additional software which takes up lot of space but still would like to have the graphical environment. Thanks

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  • visualizing enter symbol in java (Serif/SansSerif preferred)

    - by Tom
    How can I display the graphical "enter symbol" within java applet using fonts? I want to show "?", which is U+21B5 DOWNWARDS ARROW WITH CORNER LEFTWARDS. – I want to draw this to applet's screen so that it works in WIN, LINUX, MACOSX, etc. Is there a font available that makes this possible or should I draw it manually somehow? g2d.setFont("SymbolFont??which one"); g2d.drawString(myenterSymbolHere,x,Y);

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  • SQL Server and Hyper-V Dynamic Memory Part 2

    - by SQLOS Team
    Part 1 of this series was an introduction and overview of Hyper-V Dynamic Memory. This part looks at SQL Server memory management and how the SQL engine responds to changing OS memory conditions.   Part 2: SQL Server Memory Management As with any Windows process, sqlserver.exe has a virtual address space (VAS) of 4GB on 32-bit and 8TB in 64-bit editions. Pages in its VAS are mapped to pages in physical memory when the memory is committed and referenced for the first time. The collection of VAS pages that have been recently referenced is known as the Working Set. How and when SQL Server allocates virtual memory and grows its working set depends on the memory model it uses. SQL Server supports three basic memory models:   1. Conventional Memory Model   The Conventional model is the default SQL Server memory model and has the following properties: - Dynamic - can grow or shrink its working set in response to load and external (operating system) memory conditions. - OS uses 4K pages – (not to be confused with SQL Server “pages” which are 8K regions of committed memory).- Pageable - Can be paged out to disk by the operating system.   2. Locked Page Model The locked page memory model is set when SQL Server is started with "Lock Pages in Memory" privilege*. It has the following characteristics: - Dynamic - can grow or shrink its working set in the same way as the Conventional model.- OS uses 4K pages - Non-Pageable – When memory is committed it is locked in memory, meaning that it will remain backed by physical memory and will not be paged out by the operating system. A common misconception is to interpret "locked" as non-dynamic. A SQL Server instance using the locked page memory model will grow and shrink (allocate memory and release memory) in response to changing workload and OS memory conditions in the same way as it does with the conventional model.   This is an important consideration when we look at Hyper-V Dynamic Memory – “locked” memory works perfectly well with “dynamic” memory.   * Note in “Denali” (Standard Edition and above), and in SQL 2008 R2 64-bit (Enterprise and above editions) the Lock Pages in Memory privilege is all that is required to set this model. In 2008 R2 64-Bit standard edition it also requires trace flag 845 to be set, in 2008 R2 32-bit editions it requires sp_configure 'awe enabled' 1.   3. Large Page Model The Large page model is set using trace flag 834 and potentially offers a small performance boost for systems that are configured with large pages. It is characterized by: - Static - memory is allocated at startup and does not change. - OS uses large (>2MB) pages - Non-Pageable The large page model is supported with Hyper-V Dynamic Memory (and Hyper-V also supports large pages), but you get no benefit from using Dynamic Memory with this model since SQL Server memory does not grow or shrink. The rest of this article will focus on the locked and conventional SQL Server memory models.   When does SQL Server grow? For “dynamic” configurations (Conventional and Locked memory models), the sqlservr.exe process grows – allocates and commits memory from the OS – in response to a workload. As much memory is allocated as is required to optimally run the query and buffer data for future queries, subject to limitations imposed by:   - SQL Server max server memory setting. If this configuration option is set, the buffer pool is not allowed to grow to more than this value. In SQL Server 2008 this value represents single page allocations, and in “Denali” it represents any size page allocations and also managed CLR procedure allocations.   - Memory signals from OS. The operating system sets a signal on memory resource notification objects to indicate whether it has memory available or whether it is low on available memory. If there is only 32MB free for every 4GB of memory a low memory signal is set, which continues until 64MB/4GB is free. If there is 96MB/4GB free the operating system sets a high memory signal. SQL Server only allocates memory when the high memory signal is set.   To summarize, for SQL Server to grow you need three conditions: a workload, max server memory setting higher than the current allocation, high memory signals from the OS.    When does SQL Server shrink caches? SQL Server as a rule does not like to return memory to the OS, but it will shrink its caches in response to memory pressure. Memory pressure can be divided into “internal” and “external”.   - External memory pressure occurs when the operating system is running low on memory and low memory signals are set. The SQL Server Resource Monitor checks for low memory signals approximately every 5 seconds and it will attempt to free memory until the signals stop.   To free memory SQL Server does the following: ·         Frees unused memory. ·         Notifies Memory Manager Clients to release memory o   Caches – Free unreferenced cache objects. o   Buffer pool - Based on oldest access times.   The freed memory is released back to the operating system. This process continues until the low memory resource notifications stop.    - Internal memory pressure occurs when the size of different caches and allocations increase but the SQL Server process needs to keep its total memory within a target value. For example if max server memory is set and certain caches are growing large, it will cause SQL to free memory for re-use internally, but not to release memory back to the OS. If you lower the value of max server memory you will generate internal memory pressure that will cause SQL to release memory back to the OS.    Memory pressure handling has not changed much since SQL 2005 and it was described in detail in a blog post by Slava Oks.   Note that SQL Server Express is an exception to the above behavior. Unlike other editions it does not assume it is the most important process running on the system but tries to be more “desktop” friendly. It will empty its working set after a period of inactivity.   How does SQL Server respond to changing OS memory?    In SQL Server 2005 support for Hot-Add memory was introduced. This feature, available in Enterprise and above editions, allows the server to make use of any extra physical memory that was added after SQL Server started. Being able to add physical memory when the system is running is limited to specialized hardware, but with the Hyper-V Dynamic Memory feature, when new memory is allocated to a guest virtual machine, it looks like hot-add physical memory to the guest. What this means is that thanks to the hot-add memory feature, SQL Server 2005 and higher can dynamically grow if more “physical” memory is granted to a guest VM by Hyper-V dynamic memory.   SQL Server checks OS memory every second and dynamically adjusts its “target” (based on available OS memory and max server memory) accordingly.   In “Denali” Standard Edition will also have sqlserver.exe support for hot-add memory when running virtualized (i.e. detecting and acting on Hyper-V Dynamic Memory allocations).   How does a SQL Server workload in a guest VM impact Hyper-V dynamic memory scheduling?   When a SQL workload causes the sqlserver.exe process to grow its working set, the Hyper-V memory scheduler will detect memory pressure in the guest VM and add memory to it. SQL Server will then detect the extra memory and grow according to workload demand. In our tests we have seen this feedback process cause a guest VM to grow quickly in response to SQL workload - we are still working on characterizing this ramp-up.    How does SQL Server respond when Hyper-V removes memory from a guest VM through ballooning?   If pressure from other VM's cause Hyper-V Dynamic Memory to take memory away from a VM through ballooning (allocating memory with a virtual device driver and returning it to the host OS), Windows Memory Manager will page out unlocked portions of memory and signal low resource notification events. When SQL Server detects these events it will shrink memory until the low memory notifications stop (see cache shrinking description above).    This raises another question. Can we make SQL Server release memory more readily and hence behave more "dynamically" without compromising performance? In certain circumstances where the application workload is predictable it may be possible to have a job which varies "max server memory" according to need, lowering it when the engine is inactive and raising it before a period of activity. This would have limited applicaability but it is something we're looking into.   What Memory Management changes are there in SQL Server “Denali”?   In SQL Server “Denali” (aka SQL11) the Memory Manager has been re-written to be more efficient. The main changes are summarized in this post. An important change with respect to Hyper-V Dynamic Memory support is that now the max server memory setting includes any size page allocations and managed CLR procedure allocations it now represents a closer approximation to total sqlserver.exe memory usage. This makes it easier to calculate a value for max server memory, which becomes important when configuring virtual machines to work well with Hyper-V Dynamic Memory Startup and Maximum RAM settings.   Another important change is no more AWE or hot-add support for 32-bit edition. This means if you're running a 32-bit edition of Denali you're limited to a 4GB address space and will not be able to take advantage of dynamically added OS memory that wasn't present when SQL Server started (though Hyper-V Dynamic Memory is still a supported configuration).   In part 3 we’ll develop some best practices for configuring and using SQL Server with Dynamic Memory. Originally posted at http://blogs.msdn.com/b/sqlosteam/

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  • The HTG Guide to Using a Bluetooth Keyboard with Your Android Device

    - by Matt Klein
    Android devices aren’t usually associated with physical keyboards. But, since Google is now bundling their QuickOffice app with the newly-released Kit-Kat, it appears inevitable that at least some Android tablets (particularly 10-inch models) will take on more productivity roles. In recent years, physical keyboards have been rendered obsolete by swipe style input methods such as Swype and Google Keyboard. Physical keyboards tend to make phones thick and plump, and that won’t fly today when thin (and even flexible and curved) is in vogue. So, you’ll be hard-pressed to find smartphone manufacturers launching new models with physical keyboards, thus rendering sliders to a past chapter in mobile phone evolution. It makes sense to ditch the clunky keyboard phone in favor of a lighter, thinner model. You’re going to carry around in your pocket or purse all day, why have that extra bulk and weight? That said, there is sound logic behind pairing tablets with keyboards. Microsoft continues to plod forward with its Surface models, and while critics continue to lavish praise on the iPad, its functionality is obviously enhanced and extended when you add a physical keyboard. Apple even has an entire page devoted specifically to iPad-compatible keyboards. But an Android tablet and a keyboard? Does such a thing even exist? They do actually. There are docking keyboards and keyboard/case combinations, there’s the Asus Transformer family, Logitech markets a Windows 8 keyboard that speaks “Android”, and these are just to name a few. So we know that keyboard products that are designed to work with Android exist, but what about an everyday Bluetooth keyboard you might use with Windows or OS X? How-To Geek wanted look at how viable it is to use such a keyboard with Android. We conducted some research and examined some lists of Android keyboard shortcuts. Most of what we found was long outdated. Many of the shortcuts don’t even apply anymore, while others just didn’t work. Regardless, after a little experimentation and a dash of customization, it turns out using a keyboard with Android is kind of fun, and who knows, maybe it will catch on. Setting things up Setting up a Bluetooth keyboard with Android is very easy. First, you’ll need a Bluetooth keyboard and of course an Android device, preferably running version 4.1 (Jelly Bean) or higher. For our test, we paired a second-generation Google Nexus 7 running Android 4.3 with a Samsung Series 7 keyboard. In Android, enable Bluetooth if it isn’t already on. We’d like to note that if you don’t normally use Bluetooth accessories and peripherals with your Android device (or any device really), it’s best practice to leave Bluetooth off because, like GPS, it drains the device’s battery more quickly. To enable Bluetooth, simply go to “Settings” -> “Bluetooth” and tap the slider button to “On”. To set up the keyboard, make sure it is on and then tap “Bluetooth” in the Android settings. On the resulting screen, your Android device should automatically search for and hopefully find your keyboard. If you don’t get it right the first time, simply turn the keyboard on again and then tap “Search for Devices” to try again. If it still doesn’t work, make sure you have fresh batteries and the keyboard isn’t paired to another device. If it is, you will need to unpair it before it will work with your Android device (consult your keyboard manufacturer’s documentation or Google if you don’t know how to do this). When Android finds your keyboard, select it under “Available Devices” … … and you should be prompted to type in a code: If successful, you will see that device is now “Connected” and you’re ready to go. If you want to test things out, try pressing the “Windows” key (“Apple” or “Command”) + ESC, and you will be whisked to your Home screen. So, what can you do? Traditional Mac and Windows users know there’s usually a keyboard shortcut for just about everything (and if there isn’t, there’s all kinds of ways to remap keys to do a variety of commands, tasks, and functions). So where does Android fall in terms of baked-in keyboard commands? There answer to that is kind of enough, but not too much. There are definitely established combos you can use to get around, but they aren’t clear and there doesn’t appear to be any one authority on what they are. Still, there is enough keyboard functionality in Android to make it a viable option, if only for those times when you need to get something done (long e-mail or important document) and an on-screen keyboard simply won’t do. It’s important to remember that Android is, and likely always will be a touch-first interface. That said, it does make some concessions to physical keyboards. In other words, you can get around Android fairly well without having to lift your hands off the keys, but you will still have to tap the screen regularly, unless you add a mouse. For example, you can wake your device by tapping a key rather than pressing its power button. However, if your device is slide or pattern-locked, then you’ll have to use the touchscreen to unlock it – a password or PIN however, works seamlessly with a keyboard – other things like widgets and app controls and features, have to be tapped. You get the idea. Keyboard shortcuts and navigation As we said, baked-in keyboard shortcut combos aren’t necessarily abundant nor apparent. The one thing you can always do is search. Any time you want to Google something, start typing from the Home screen and the search screen will automatically open and begin displaying results. Other than that, here is what we were able to figure out: ESC = go back CTRL + ESC = menu CTRL + ALT + DEL = restart (no questions asked) ALT + SPACE = search page (say “OK Google” to voice search) ALT + TAB (ALT + SHIFT + TAB) = switch tasks Also, if you have designated volume function keys, those will probably work too. There’s also some dedicated app shortcuts like calculator, Gmail, and a few others: CMD + A = calculator CMD + C = contacts CMD + E = e-mail CMD + G = Gmail CMD + L = Calendar CMD + P = Play Music CMD + Y = YouTube Overall, it’s not a long comprehensive list and there’s no dedicated keyboard combos for the full array of Google’s products. Granted, it’s hard to imagine getting a lot of mileage out of a keyboard with Maps but with something like Keep, you could type out long, detailed lists on your tablet, and then view them on your smartphone when you go out shopping. You can also use the arrow keys to navigate your Home screen over shortcuts and open the app drawer. When something on the screen is selected, it will be highlighted in blue. Press “Enter” to open your selection. Additionally, if an app has its own set of shortcuts, e.g. Gmail has quite a few unique shortcuts to it, as does Chrome, some – though not many – will work in Android (not for YouTube though). Also, many “universal” shortcuts such as Copy (CTRL + C), Cut (CTRL + X), Paste (CTRL + V), and Select All (CTRL + A) work where needed – such as in instant messaging, e-mail, social media apps, etc. Creating custom application shortcuts What about custom shortcuts? When we were researching this article, we were under the impression that it was possible to assign keyboard combinations to specific apps, such as you could do on older Android versions such as Gingerbread. This no long seems to be the case and nowhere in “Settings” could we find a way to assign hotkey combos to any of our favorite, oft-used apps or functions. If you do want custom keyboard shortcuts, what can you do? Luckily, there’s an app on Google Play that allows you to, among other things, create custom app shortcuts. It is called External Keyboard Helper (EKH) and while there is a free demo version, the pay version is only a few bucks. We decided to give EKH a whirl and through a little experimentation and finally reading the developer’s how-to, we found we could map custom keyboard combos to just about anything. To do this, first open the application and you’ll see the main app screen. Don’t worry about choosing a custom layout or anything like that, you want to go straight to the “Advanced settings”: In the “Advanced settings” select “Application shortcuts” to continue: You can have up to 16 custom application shortcuts. We are going to create a custom shortcut to the Facebook app. We choose “A0”, and from the resulting list, Facebook. You can do this for any number of apps, services, and settings. As you can now see, the Facebook app has now been linked to application-zero (A0): Go back to the “Advanced settings” and choose “Customize keyboard mappings”: You will be prompted to create a custom keyboard layout so we choose “Custom 1”: When you choose to create a custom layout, you can do a great many more things with your keyboard. For example, many keyboards have predefined function (Fn) keys, which you can map to your tablet’s brightness controls, toggle WiFi on/off, and much more. A word of advice, the application automatically remaps certain keys when you create a custom layout. This might mess up some existing keyboard combos. If you simply want to add some functionality to your keyboard, you can go ahead and delete EKH’s default changes and start your custom layout from scratch. To create a new combo, select “Add new key mapping”: For our new shortcut, we are going to assign the Facebook app to open when we key in “ALT + F”. To do this, we press the “F” key while in the “Scancode” field and we see it returns a value of “33”. If we wanted to use a different key, we can press “Change” and scan another key’s numerical value. We now want to assign the “ALT” key to application “A0”, previously designated as the Facebook app. In the “AltGr” field, we enter “A0” and then “Save” our custom combo. And now we see our new application shortcut. Now, as long as we’re using our custom layout, every time we press “ALT + F”, the Facebook app will launch: External Keyboard Helper extends far beyond simple application shortcuts and if you are looking for deeper keyboard customization options, you should definitely check it out. Among other things, EKH also supports dozens of languages, allows you to quickly switch between layouts using a key or combo, add up to 16 custom text shortcuts, and much more! It can be had on Google Play for $2.53 for the full version, but you can try the demo version for free. More extensive documentation on how to use the app is also available. Android? Keyboard? Sure, why not? Unlike traditional desktop operating systems, you don’t need a physical keyboard and mouse to use a mobile operating system. You can buy an iPad or Nexus 10 or Galaxy Note, and never need another accessory or peripheral – they work as intended right out of the box. It’s even possible you can write the next great American novel on one these devices, though that might require a lot of practice and patience. That said, using a keyboard with Android is kind of fun. It’s not revelatory but it does elevate the experience. You don’t even need to add customizations (though they are nice) because there are enough existing keyboard shortcuts in Android to make it usable. Plus, when it comes to inputting text such as in an editor or terminal application, we fully advocate big, physical keyboards. Bottom line, if you’re looking for a way to enhance your Android tablet, give a keyboard a chance. Do you use your Android device for productivity? Is a physical keyboard an important part of your setup? Do you have any shortcuts that we missed? Sound off in the comments and let us know what you think.     

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  • Building services with .Net Part 1

    - by Allan Rwakatungu
    On the 26th of May 2010 , I made a presentation to the .NET user group meeting (thanks to Malisa Ncube for organizing this event every month … ). If you missed my presentation , we talked about why we should all be building services … better still using the .NET framework. This blog post is an introduction to services , why you would want to build services and how you can build services using the .NET framework. What is a service? OASIS defines service as "a mechanism to enable access to one or more capabilities, where the access is provided using a prescribed interface and is exercised consistent with constraints and policies as specified by the service description." [1]. If the above definition sounds to academic , you can also define a service as loosely coupled units of functionality that have no calls to each other embedded in the. Instead of services embedding calls to each other in their service code they use defined protocols that describe how services pass and parse messages. This is a good way to think about services if you’re from an objected oriented background. While in object oriented programming functions make calls to each other, in service oriented programming, functions pass messages between each other. Why would you want to use services? 1. If your enterprise architecture looks like this   Services are the building blocks for SOA . With SOA you can move away from the sphaggetti infrastructure that is common in most enterprises. The complexity or lack of visibility of the integration points in your enterprises makes it difficult and costly to implement new initiatives and changes into the business - and even impossible in some cases - as it is not possible to identify the impact a change in one system might have to other systems. With services you can move to an architecture like this Your building blocks from Spaghetti infrastructure to something that is more well-defined and manageable to achieve cost efficiency and not least business agility - enabling you to react to changes in the market with speed and achieve operational efficiency and control are services. 2. If you want to become the Gates or Zuckerburger. Have you heard about Web 2.0 ? Mashups? Software as a service (SAAS) ? Cloud computing ?   They all offer you the opportunity to have scalable but low cost business models and they built using services.  Some of my favorite companies that leverage services for their business models include  https://www.salesforce.com/ (cloud CRM) http://www. twitter.com (more people use twitter clients built by 3rd parties than their official clients) http://www.kayak.com/ (compares data from other travel sites to give information to users in one location) Services with the .NET framework      If you are a .NET developer and you want to develop services, Windows Communication Framework (WCF) is the tool for you. WCF is Microsoft’s unified programming model (service model) for building service oriented applications. ( Before .NET 3.0 you had several models for programming services in .NET including .NET remoting, Web services (ASMX), COM +, Microsoft Messaging queuing (MSMQ) etc, after .NET 3.0 the programming model was unified into one i.e. WCF ). Windows Communication Framework (WCF) provides you 1. An Software Development Kit (SDK) for creating SOA applications 2. A runtime for running services on the Windows platform Why should you use Windows Communication Foundation if you’re programming services?   1. It supports interoperable and open standards e.g. WS* protocols for programming SOAP services 2. It has a unified programming model. Whether you use TCP or Http or Pipes or transmitting using Messaging Queues, programmers need to learn just one way to program. Previously you had .NET remoting, MSMQ, Web services, COM+ and they were all done differently 3. Productive programming model You don’t have to worry about all the plumbing involved to write services. You have a rich declarative programming model to add stuff like logging, transactions, and reliable messages in-built in the Windows Communication Framework. Understanding services in WCF The basic principles of WCF are as easy as ABC A – Address This is where the service is located B- Binding This describes how you communicate with the service e.g. Use TCP, HTTP or both. How to exchange security information with the service etc. C – Contract This defines what the service can do. E.g. Pay water bill, Make a phone call A - Addresses In WCF, an address is a combination of transport, server name, port and path Example addresses may include http://localhost:8001 net.tcp://localhost:8002/MyService net.pipe://localhost/MyPipe net.msmq://localhost/private/MyService net.msmq://localhost/MyService B- Binding   There are numerous ways to communicate with services , different ways that a message can be formatted/sent/secured, that allows you to tailor your service for the compatibility/performance you require for your solution. Transport You can use HTTP TCP MSMQ , Named pipes, Your own custom transport etc Message You  can send a plain text binary, Message Transmission Optimization Mechanism (MTOM) message Communication security No security Transport security Message security Authenticating and authorizing callers etc Behaviour You service can support Transactions Be reliable Use queues Support ajax etc C - Contract You define what your service can do using Service contracts :- Define operations that your service can do, communications and behaviours Data contracts :- Define the messages that are passed from and into your service and how they are formatted Fault contracts :- Defines errors types in your service   As an example, suppose your service service shows money. You define your service contract using a interface [ServiceContract] public interface IShowMeTheMoney {   [OperationContract]    Money Show(); } You define the data contract by annotating a class it with the Data Contract attribute and fields you want to pass in the message as Data Members. (Note:- In the latest versions of WCF you dont have to use attributes if you passing all the objects properties in the message) [DataContract] public Money {   [DataMember]   public string Currency { get; set; }   [DataMember]   public Decimal Amount { get; set; }   public string Comment { get; set; } } Features of Windows Communication Foundation Windows Communication Foundation is not only simple but feature rich , offering you several options to tweak your service to fit your business requirements. Some of the features of WCF include 1. Workflow services You can combine WCF with Windows WorkFlow Foundation (WWF) to write workflow type services 2. Control how your data (messages) are transferred and serialized e.g. you can serialize your business objects as XML or binary 3. control over session management , instance creation and concurrency management without writing code if you like 4. Queues and reliable sessions. You can store messages from the sending client and later forward them to the receiving application. You can also guarantee that messages will arrive at their destincation. 5.Transactions:  You can have different services participate in a transaction operations that can be rolled back if needed 6. Security. WCF has rich features for authorization and authentication  as well as keep audit trails 7. Web programming model. WCF allows developers to expose services as non SOAP endpoints 8. Inbuilt features that you can use to write JSON and services that support AJAX applications And lots more In my next blog I will show you how you can use WCF features to write a real world business service.               Normal 0 false false false EN-US X-NONE X-NONE MicrosoftInternetExplorer4 Normal 0 false false false EN-US X-NONE X-NONE MicrosoftInternetExplorer4 ]] /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin-top:0in; mso-para-margin-right:0in; mso-para-margin-bottom:10.0pt; mso-para-margin-left:0in; line-height:115%; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:"Times New Roman"; mso-bidi-theme-font:minor-bidi;}

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