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• Wildcards!

  - by Tim Dexter

  Yes, its been a while, Im sorry, mumble, mumble ... no excuses. Well other than its been, as my son would say 'hecka busy.' On a brighter note I see Kan has been posting some cool stuff in my absence, long may he continue! I received a question today asking about using a wildcard in a template, something like: <?if:INVOICE = 'MLP*'?> where * is the wildcard Well that particular try does not work but you can do it without building your own wildcard function. XSL, the underpinning language of the RTF templates, has some useful string functions - you can find them listed here. I used the starts-with function to achieve a simple wildcard scenario but the contains can be used in conjunction with some of the others to build something more sophisticated. Assume I have a a list of friends and the amounts of money they owe me ... Im very generous and my interest rates a pretty competitive :0) <ROWSET> <ROW> <NAME>Andy</NAME> <AMT>100</AMT> </ROW> <ROW> <NAME>Andrew</NAME> <AMT>60</AMT> </ROW> <ROW> <NAME>Aaron</NAME> <AMT>50</AMT> </ROW> <ROW> <NAME>Alice</NAME> <AMT>40</AMT> </ROW> <ROW> <NAME>Bob</NAME> <AMT>10</AMT> </ROW> <ROW> <NAME>Bill</NAME> <AMT>100</AMT> </ROW> Now, listing my friends is easy enough <for-each:ROW> <NAME> <AMT> <end for-each> but lets say I just want to see all my friends beginning with 'A'. To do that I can use an XPATH expression to filter the data and tack it on to the for-each expression. This is more efficient that using an 'if' statement just inside the for-each. <?for-each:ROW[starts-with(NAME,'A')]?> will find me all the A's. The square braces denote the start of the XPATH expression. starts-with is the function Im calling and Im passing the value I want to check i.e. NAME and the string Im looking for. Just substitute in the characters you are looking for. You can of course use the function in a if statement too. <?if:starts-with(NAME,'A')?><?attribute@incontext:color;'red'?><?end if?> Notice I removed the square braces, this will highlight text red if the name begins with an 'A' You can even use the function to do conditional calculations: <?sum (AMT[starts-with(../NAME,'A')])?> Sum only the amounts where the name begins with an 'A' Notice the square braces are back, its a function we want to apply to the AMT field. Also notice that we need to use ../NAME. The AMT and NAME elements are at the same level in the tree, so when we are at the AMT level we need the ../ to go up a level to then come back down to test the NAME value. I have built out the above functions in a sample template here. Huge prizes for the first person to come up with a 'true' wildcard solution i.e. if NAME like '*im*exter* demand cash now!

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• Adding a Network Loopback Adapter to Windows 8

  - by Greg Low

  I have to say that I continue to be frustrated with finding out how to do things in Windows 8. Here's another one and it's recorded so it might help someone else. I've also documented what I tried so that if anyone from the product group ever reads this, they'll understand how I searched for it and might try to make it easier.I wanted to add a network loopback adapter, to have a fixed IP address to work with when using an "internal" network with Hyper-V. (The fact that I even need to do this is also painful. I don't know why Hyper-V can't make it easy to work with host system folders, etc. as easily as I can with VirtualPC, VirtualBox, etc. but that's a topic for another day).In the end, what I needed was a known IP address on the same network that my guest OS was using, via the internal network (which allows connectivity from the host OS to/from guest OS's).I started by looking in the network adapters areas but there is no "add" functionality there. Realising that this was likely to be another unexpected challenge, I resorted to searching for info on doing this. I found KB article 2777200 entitled "Installing the Microsoft Loopback Adapter in Windows 8 and Windows Server 2012". Aha, I thought that's what I'd need. It describes the symptom as "You are trying to install the Microsoft Loopback Adapter, but are unable to find it." and that certainly sounded like me. There's a certain irony in documenting that something's hard to find instead of making it easier to find. Anyway, you'd hope that in that article, they'd then provide a step by step example of how to do it, but what they supply is this: The Microsoft Loopback Adapter was renamed in Windows 8 and Windows Server 2012. The new name is "Microsoft KM-TEST Loopback Adapter". When using the Add Hardware Wizard to manually add a network adapter, choose Manufacturer "Microsoft" and choose network adapter "Microsoft KM-TEST Loopback Adapter".The trick with this of course is finding the "Add Hardware Wizard". In Control Panel -> Hardware and Sound, there are options to "Add a device" and for "Device Manager". I tried the "Add a device" wizard (seemed logical to me) but after that wizard tries it's best, it just tells you that there isn't any hardware that it thinks it needs to install. It offers a link for when you can't find what you're looking for, but that leads to a generic help page that tells you how to do things like turning on your printer.In Device Manager, I checked the options in the program menus, and nothing useful was present. I even tried right-clicking "Network adapters", hoping that would lead to an option to add one, also to no avail.So back to the search engine I went, to try to find out where the "Add Hardware Wizard" is. Turns out I was in the right place in Device Manager, but I needed to right-click the computer's name, and choose "Add Legacy Hardware". No doubt that hasn't changed location lately but it's a while since I needed to add one so I'd forgotten. Regardless, I'm left wondering why it couldn't be in the menu as well.Anyway, for a step by step list, you need to do the following:1. From Control Panel, select "Device Manager" under the "Devices and Printers" section of the "Hardware and Sound" tab.2. Right-click the name of the computer at the top of the tree, and choose "Add Legacy Hardware".3. In the "Welcome to the Add Hardware Wizard" window, click Next.4. In the "The wizard can help you install other hardware" window, choose "Install the hardware that I manually select from a list" option and click Next.5. In the "The wizard did not find any new hardware on your computer" window, click Next.6. In the "From the list below, select the type of hardware you are installing" window, select "Network Adapters" from the list, and click Next.7. In the "Select Network Adapter" window, from the Manufacturer list, choose Microsoft, then in the Network Adapter window, choose "Microsoft KM-TEST Loopback Adapter", then click Next.8. In the "The wizard is ready to install your hardware" window, click Next.9. In the "Completing the Add Hardware Wizard" window, click Finish.Then you need to continue to set the IP address, etc.10. Back in Control Panel, select the "Network and Internet" tab, click "View Network Status and Tasks".11. In the "View your basic network information and set up connections" window, click "Change adapter settings".12. Right-click the new adapter that has been added (find it in the list by checking the device name of "Microsoft KM-TEST Loopback Adapter"), and click Properties.   

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• Adding a DLL to the GAC in Windows 7

  - by Jim Giercyk

  I recently created a DLL and I wanted to reference it from a project I was developing in Visual Studio.  In previous versions of Windows, doing so was simply a matter of dropping the DLL file in the C:\Windows\assembly folder.  That would add the DLL to the Global Assembly Cache (GAC) and make it accessible in Visual Studio.  However, as is often the case, Window 7 is different.  Even if you have Administrator privileges on your machine, you still do not have permission to drop a file in the assembly folder.  Undaunted, I thought about using the old DOS command line utility gacutil.exe.  Microsoft developed the tool as part of the .Net framework, and it is available in the Windows SDK Framework Tools.  If you have never used gacutil.exe before, you can find out everything you ever wanted to know but were afraid to ask here: http://msdn.microsoft.com/en-us/library/ex0ss12c(v=vs.80).aspx .  Unfortunately, if you do not have the Windows SDK loaded on your development machine, you will need to install it to use gacutil, but it is relatively quick and painless, and the framework tools are very useful.  Look here for your latest SDK: http://www.microsoft.com/download/en/search.aspx?q=Windows%20SDK .   After installing the SDK, I tried installing my DLL to the GAC by running gacutil from a DOS command line: That’s odd.  Microsoft is shipping a tool that cannot be executed even with Administrator rights?  Let me stop here and say that I am by no means a Windows security expert, so I actually did contact my system administrators, and they were not sure how to fix the problem….there must be a super administrator access level, but it isn’t available to your average developer in my company.  The solution outlined here is working within the boundaries of a normal windows Administrator. So, now the hacker in me bubbles to the surface.  What if I were to create a simple BAT file containing the gacutil command?  It’s so crazy it just might work!  Ugh!  I was starting to think this would never work, but then I realized that simply executing a batch program did not change my level of access.  Typically in Windows 7, you would select the “Run As Administrator” option to temporarily act as an administrator for the purpose of executing a process.  However, that option is not available for BAT files run from the command line.  SOLUTION: Create a desktop shortcut to execute the BAT file, which in turn will execute the line command…..are you still with me?  I created a shortcut and pointed it to my batch file.  Theoretically, all I need to do now is right-click on the shortcut and select “Run As Administrator” and we’re good, right?  Well, kinda.  If you notice the syntax of my BAT file, the name of the DLL is passed in as a parameter.  Therefore, I either have to hard-code the file name in the BAT program (YUCK!!), or I can leave the parameter and drag the DLL file to the shortcut and drop it.  Sweet, drag-and-drop works for me…..but if I use the drag-and-drop method, there is no way for me to right-click and select “Run As Administrator”.  That is not a problem…..I simply have to adjust the properties of the shortcut I created and I am in business.  I Right-clicked on the shortcut and select “Properties”.  Under the “Shortcut” tab there is an “Advanced” button…..I clicked it. All I needed to do was check the “Run As Administrator” box: In summary, what I have done is create a BAT file to execute a command line utility, gacutil.exe.  Then, rather than executing the BAT file from the command line, I created a desktop shortcut to run it and set the shortcut properties to “Run As Administrator”.  This will effectively mean I am executing the command line utility with Administrator privileges.  Pretty sneaky. Now, when I drag the DLL file  over to the shortcut, it starts the BAT file and adds the DLL to the assembly cache.  I created another BAT file to remove a DLL from the GAC in case the need should arise.  The code for that is: Give it a try.  I can’t imagine why updating the GAC has been made into such a chore in Windows 7.  Hopefully there is a service pack in the works that will give developers the functionality they had in Windows XP, but in the meantime, this workaround is extremely useful.

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• Customizing UPK outputs (Part 2 - Player)

  - by [email protected]

  There are a few things that can be done to give the Player output a personalized look to match your corporate branding. In my previous post, I talked about changing the logo. In addition to the logo, you can change the graphic in the heading, button colors, border colors and many other items. Prior to making any customizations, I strongly recommend making a copy of the existing Player style. This will give you a backup in case things go wrong. I'd also recommend that you create your own brand. This way, when you install the newest updates from us, your brand will remain intact. Creating your own brand is pretty easy. Make sure you have modify permissions on the publishing styles directory, if you are using a multi-user installation. Under the Publishing/Styles folder, create a new folder with your company name. Copy all the publishing styles from the UPK folder to your newly created folder. Now, when you go through the Publishing wizard, you will have two categories to choose from: the UPK category or your custom category. Now, for updating the Player output. First, the graphic that appears on the right hand side of the Player. If you're using a multi-user installation, check out the player style from your custom brand. Open the player style. Open the img folder. The file named "banner_image.png" represents the graphic that appears on the right hand side of the player. It is currently sized at 425 x 54. Try to keep your graphic about the same size. Rename your graphic file to be "banner_image.png", and drag it into the img folder. Save the package. Check in the package if you are in a multi-user installation. You've just updated the banner heading! Next, let's work on updating some of the other colors in the player. All the customizable areas are located in the skin.css file which is in the root of the Player style. Many of our customers update the colors to match their own theme. You don't have to be a programmer to make these changes, honest. :) To change the colors in the player: Make a copy of the original skin.css file. (This is to make sure you have a working version to revert to, in case something goes wrong.) Open the skin.css file from the Player package. You can edit it using Notepad. Make the desired changes. Save the file. Save the package. Publish to view your new changes. When you open the skin.css, you will see groupings like this: .headerDivbar { height: 21px; background-color: #CDE2FD; } Change the value of the background-color to the color of your choice. Note that you cannot use "red" as a color, but rather you should enter the hexadecimal color code. If you don't know the color code, search the web for "hexadecimal colors" and you'll find many sites to provide the information. Here are a few of the variables that you can update. Heading: .headerDivbar -this changes the color of the banner that appears under the graphic Button colors: .navCellOn - changes the color of the mode buttons when your mouse is hovering on them. .navCellOff - changes the color of the mode buttons when the mouse is not over them Lines: .thorizontal - this is the color of the horizontal lines surrounding the outline .tvertical - this is the color of the vertical lines on the left and right margin in the outline. .tsep - this is the color of the line that separates the outline from the content area Search frame: .tocSearchColor - this is the color of the search area .tocFrameText - this is the background color of the TOC tree. Hint: If you want to try out the changes prior to updating the style, you can update the skin.css in some content you've already published for the player (it's located in the css folder of the player package). This way, you can immediately see the changes without going through publishing. Once you're happy with the changes, update the skin.css in player style. Want to customize more? Refer to the "Customizing the Player" section of the Content Development manual for more details on all the options in the skin.css that can be changed, and pictures of what each variable controls. I'd love to see how you've customized the player for your corporate needs. Also, if there are other areas of the player you'd like to modify but have not been able to, let us know. Feel free to share your thoughts in the comments. --Maria Cozzolino, Manager of Requirements & UI Design for UPK

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• Getting App.config to be configuration specific in VS2010

  - by MarkPearl

  I recently wanted to have a console application that had configuration specific settings. For instance, if I had two configurations “Debug” and “Release”, depending on the currently selected configuration I wanted it to use a specific configuration file (either debug or config). If you are wanting to do something similar, here is a potential solution that worked for me. Setting up a demo app to illustrate the point First, let’s set up an application that will demonstrate the most basic concept. using System; using System.Configuration; namespace ConsoleSpecificConfiguration { class Program { static void Main(string[] args) { Console.WriteLine("Config"); Console.WriteLine(ConfigurationManager.AppSettings["Example Config"]); Console.ReadLine(); } } }   This does a really simple thing. Display a config when run. To do this, you also need a config file set up. My default looks as follows… <?xml version="1.0" encoding="utf-8" ?> <configuration> <appSettings> <add key="Example Config" value="Default"/> </appSettings> </configuration>   Your entire solution will look as follows… Running the project you will get the following amazing output…   Let’s now say instead of having one config file we want depending on whether we are running in “Debug” or “Release” for the solution configuration we want different config settings to be propagated across you can do the following… Step 1 – Create alternate config Files First add additional config files to your solution. You should have some form of naming convention for these config files, I have decided to follow a similar convention to the one used for web.config, so in my instance I am going to add a App.Debug.config and a App.Release.config file BUT you can follow any naming convention you want provided you wire up the rest of the approach to use this convention. My files look as follows.. App.Debug.config <?xml version="1.0" encoding="utf-8" ?> <configuration> <appSettings> <add key="Example Config" value="Debug"/> </appSettings> </configuration>   App.Release.config <?xml version="1.0" encoding="utf-8" ?> <configuration> <appSettings> <add key="Example Config" value="Release"/> </appSettings> </configuration>   Your solution will now look as follows… Step 2 – Create a bat file that will overwrite files The next step is to create a bat file that will overwrite one file with another. If you right click on the solution in the solution explorer there will be a menu option to add new items to the solution. Create a text file called “copyifnewer.bat” which will be our copy script. It’s contents should look as follows… @echo off echo Comparing two files: %1 with %2 if not exist %1 goto File1NotFound if not exist %2 goto File2NotFound fc %1 %2 /A if %ERRORLEVEL%==0 GOTO NoCopy echo Files are not the same. Copying %1 over %2 copy %1 %2 /y & goto END :NoCopy echo Files are the same. Did nothing goto END :File1NotFound echo %1 not found. goto END :File2NotFound copy %1 %2 /y goto END :END echo Done. Your solution should now look as follows…   Step 3 – Customize the Post Build event command line We now need to wire up everything – which we will do using the post build event command line in VS2010. Right click on your project and go to it’s properties We are now going to wire up the script so that when we build our project it will overwrite the default App.config with whatever file we want. The syntax goes as follows… call "$(SolutionDir)copyifnewer.bat" "$(ProjectDir)App.$(ConfigurationName).config" "$(ProjectDir)$(OutDir)\$(TargetFileName).config" Testing it If I now change my project configuration to Release   And then run my application I get the following output… Toggling between Release and Debug mode will show that the config file is changing each time. And that is it!

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• Clean way to use mutable implementation of Immutable interfaces for encapsulation

  - by dsollen

  My code is working on some compost relationship which creates a tree structure, class A has many children of type B, which has many children of type C etc. The lowest level class, call it bar, also points to a connected bar class. This effectively makes nearly every object in my domain inter-connected. Immutable objects would be problematic due to the expense of rebuilding almost all of my domain to make a single change to one class. I chose to go with an interface approach. Every object has an Immutable interface which only publishes the getter methods. I have controller objects which constructs the domain objects and thus has reference to the full objects, thus capable of calling the setter methods; but only ever publishes the immutable interface. Any change requested will go through the controller. So something like this: public interface ImmutableFoo{ public Bar getBar(); public Location getLocation(); } public class Foo implements ImmutableFoo{ private Bar bar; private Location location; @Override public Bar getBar(){ return Bar; } public void setBar(Bar bar){ this.bar=bar; } @Override public Location getLocation(){ return Location; } } public class Controller{ Private Map<Location, Foo> fooMap; public ImmutableFoo addBar(Bar bar){ Foo foo=fooMap.get(bar.getLocation()); if(foo!=null) foo.addBar(bar); return foo; } } I felt the basic approach seems sensible, however, when I speak to others they always seem to have trouble envisioning what I'm describing, which leaves me concerned that I may have a larger design issue then I'm aware of. Is it problematic to have domain objects so tightly coupled, or to use the quasi-mutable approach to modifying them? Assuming that the design approach itself isn't inherently flawed the particular discussion which left me wondering about my approach had to do with the presence of business logic in the domain objects. Currently I have my setter methods in the mutable objects do error checking and all other logic required to verify and make a change to the object. It was suggested that this should be pulled out into a service class, which applies all the business logic, to simplify my domain objects. I understand the advantage in mocking/testing and general separation of logic into two classes. However, with a service method/object It seems I loose some of the advantage of polymorphism, I can't override a base class to add in new error checking or business logic. It seems, if my polymorphic classes were complicated enough, I would end up with a service method that has to check a dozen flags to decide what error checking and business logic applies. So, for example, if I wanted to have a childFoo which also had a size field which should be compared to bar before adding par my current approach would look something like this. public class Foo implements ImmutableFoo{ public void addBar(Bar bar){ if(!getLocation().equals(bar.getLocation()) throw new LocationException(); this.bar=bar; } } public interface ImmutableChildFoo extends ImmutableFoo{ public int getSize(); } public ChildFoo extends Foo implements ImmutableChildFoo{ private int size; @Override public int getSize(){ return size; } @Override public void addBar(Bar bar){ if(getSize()<bar.getSize()){ throw new LocationException(); super.addBar(bar); } My colleague was suggesting instead having a service object that looks something like this (over simplified, the 'service' object would likely be more complex). public interface ImmutableFoo{ ///original interface, presumably used in other methods public Location getLocation(); public boolean isChildFoo(); } public interface ImmutableSizedFoo implements ImmutableFoo{ public int getSize(); } public class Foo implements ImmutableSizedFoo{ public Bar bar; @Override public void addBar(Bar bar){ this.bar=bar; } @Override public int getSize(){ //default size if no size is known return 0; } @Override public boolean isChildFoo return false; } } public ChildFoo extends Foo{ private int size; @Override public int getSize(){ return size; } @Override public boolean isChildFoo(); return true; } } public class Controller{ Private Map<Location, Foo> fooMap; public ImmutableSizedFoo addBar(Bar bar){ Foo foo=fooMap.get(bar.getLocation()); service.addBarToFoo(foo, bar); returned foo; } public class Service{ public static void addBarToFoo(Foo foo, Bar bar){ if(foo==null) return; if(!foo.getLocation().equals(bar.getLocation())) throw new LocationException(); if(foo.isChildFoo() && foo.getSize()<bar.getSize()) throw new LocationException(); foo.setBar(bar); } } } Is the recommended approach of using services and inversion of control inherently superior, or superior in certain cases, to overriding methods directly? If so is there a good way to go with the service approach while not loosing the power of polymorphism to override some of the behavior?

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• Representing game states in Tic Tac Toe

  - by dacman

  The goal of the assignment that I'm currently working on for my Data Structures class is to create a of Quantum Tic Tac Toe with an AI that plays to win. Currently, I'm having a bit of trouble finding the most efficient way to represent states. Overview of current Structure: AbstractGame Has and manages AbstractPlayers (game.nextPlayer() returns next player by int ID) Has and intializes AbstractBoard at the beginning of the game Has a GameTree (Complete if called in initialization, incomplete otherwise) AbstractBoard Has a State, a Dimension, and a Parent Game Is a mediator between Player and State, (Translates States from collections of rows to a Point representation Is a StateConsumer AbstractPlayer Is a State Producer Has a ConcreteEvaluationStrategy to evaluate the current board StateTransveralPool Precomputes possible transversals of "3-states". Stores them in a HashMap, where the Set contains nextStates for a given "3-state" State Contains 3 Sets -- a Set of X-Moves, O-Moves, and the Board Each Integer in the set is a Row. These Integer values can be used to get the next row-state from the StateTransversalPool SO, the principle is Each row can be represented by the binary numbers 000-111, where 0 implies an open space and 1 implies a closed space. So, for an incomplete TTT board: From the Set<Integer> board perspective: X_X R1 might be: 101 OO_ R2 might be: 110 X_X R3 might be: 101, where 1 is an open space, and 0 is a closed space From the Set<Integer> xMoves perspective: X_X R1 might be: 101 OO_ R2 might be: 000 X_X R3 might be: 101, where 1 is an X and 0 is not From the Set<Integer> oMoves perspective: X_X R1 might be: 000 OO_ R2 might be: 110 X_X R3 might be: 000, where 1 is an O and 0 is not Then we see that x{R1,R2,R3} & o{R1,R2,R3} = board{R1,R2,R3} The problem is quickly generating next states for the GameTree. If I have player Max (x) with board{R1,R2,R3}, then getting the next row-states for R1, R2, and R3 is simple.. Set<Integer> R1nextStates = StateTransversalPool.get(R1); The problem is that I have to combine each one of those states with R1 and R2. Is there a better data structure besides Set that I could use? Is there a more efficient approach in general? I've also found Point<-State mediation cumbersome. Is there another approach that I could try there? Thanks! Here is the code for my ConcretePlayer class. It might help explain how players produce new states via moves, using the StateProducer (which might need to become StateFactory or StateBuilder). public class ConcretePlayerGeneric extends AbstractPlayer { @Override public BinaryState makeMove() { // Given a move and the current state, produce a new state Point playerMove = super.strategy.evaluate(this); BinaryState currentState = super.getInGame().getBoard().getState(); return StateProducer.getState(this, playerMove, currentState); } } EDIT: I'm starting with normal TTT and moving to Quantum TTT. Given the framework, it should be as simple as creating several new Concrete classes and tweaking some things.

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• Functional Adaptation

  - by Charles Courchaine

  In real life and OO programming we’re often faced with using adapters, DVI to VGA, 1/4” to 1/8” audio connections, 110V to 220V, wrapping an incompatible interface with a new one, and so on.  Where the adapter pattern is generally considered for interfaces and classes a similar technique can be applied to method signatures.  To be fair, this adaptation is generally used to reduce the number of parameters but I’m sure there are other clever possibilities to be had.  As Jan questioned in the last post, how can we use a common method to execute an action if the action has a differing number of parameters, going back to the greeting example it was suggested having an AddName method that takes a first and last name as parameters.  This is exactly what we’ll address in this post. Let’s set the stage with some review and some code changes.  First, our method that handles the setup/tear-down infrastructure for our WCF service: 1: private static TResult ExecuteGreetingFunc<TResult>(Func<IGreeting, TResult> theGreetingFunc) 2: { 3: IGreeting aGreetingService = null; 4: try 5: { 6: aGreetingService = GetGreetingChannel(); 7: return theGreetingFunc(aGreetingService); 8: } 9: finally 10: { 11: CloseWCFChannel((IChannel)aGreetingService); 12: } 13: } Our original AddName method: 1: private static string AddName(string theName) 2: { 3: return ExecuteGreetingFunc<string>(theGreetingService => theGreetingService.AddName(theName)); 4: } Our new AddName method: 1: private static int AddName(string firstName, string lastName) 2: { 3: return ExecuteGreetingFunc<int>(theGreetingService => theGreetingService.AddName(firstName, lastName)); 4: } Let’s change the AddName method, just a little bit more for this example and have it take the greeting service as a parameter. 1: private static int AddName(IGreeting greetingService, string firstName, string lastName) 2: { 3: return greetingService.AddName(firstName, lastName); 4: } The new signature of AddName using the Func delegate is now Func<IGreeting, string, string, int>, which can’t be used with ExecuteGreetingFunc as is because it expects Func<IGreeting, TResult>.  Somehow we have to eliminate the two string parameters before we can use this with our existing method.  This is where we need to adapt AddName to match what ExecuteGreetingFunc expects, and we’ll do so in the following progression. 1: Func<IGreeting, string, string, int> -> Func<IGreeting, string, int> 2: Func<IGreeting, string, int> -> Func<IGreeting, int>   For the first step, we’ll create a method using the lambda syntax that will “eliminate” the last name parameter: 1: string lastNameToAdd = "Smith"; 2: //Func<IGreeting, string, string, int> -> Func<IGreeting, string, int> 3: Func<IGreeting, string, int> addName = (greetingService, firstName) => AddName(greetingService, firstName, lastNameToAdd); The new addName method gets us one step close to the signature we need.  Let’s say we’re going to call this in a loop to add several names, we’ll take the final step from Func<IGreeting, string, int> -> Func<IGreeting, int> in line as a lambda passed to ExecuteGreetingFunc like so: 1: List<string> firstNames = new List<string>() { "Bob", "John" }; 2: int aID; 3: foreach (string firstName in firstNames) 4: { 5: //Func<IGreeting, string, int> -> Func<IGreeting, int> 6: aID = ExecuteGreetingFunc<int>(greetingService => addName(greetingService, firstName)); 7: Console.WriteLine(GetGreeting(aID)); 8: } If for some reason you needed to break out the lambda on line 6 you could replace it with 1: aID = ExecuteGreetingFunc<int>(ApplyAddName(addName, firstName)); and use this method: 1: private static Func<IGreeting, int> ApplyAddName(Func<IGreeting, string, int> addName, string lastName) 2: { 3: return greetingService => addName(greetingService, lastName); 4: } Splitting out a lambda into its own method is useful both in this style of coding as well as LINQ queries to improve the debugging experience.  It is not strictly necessary to break apart the steps & functions as was shown above; the lambda in line 6 (of the foreach example) could include both the last name and first name instead of being composed of two functions.  The process demonstrated above is one of partially applying functions, this could have also been done with Currying (also see Dustin Campbell’s excellent post on Currying for the canonical curried add example).  Matthew Podwysocki also has some good posts explaining both Currying and partial application and a follow up post that further clarifies the difference between Currying and partial application.  In either technique the ultimate goal is to reduce the number of parameters passed to a function.  Currying makes it a single parameter passed at each step, where partial application allows one to use multiple parameters at a time as we’ve done here.  This technique isn’t for everyone or every problem, but can be extremely handy when you need to adapt a call to something you don’t control.

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• Unmet Dependencies with kdelibs5-data

  - by Jitesh

  I was trying to install Amarok 1.4 on Ubuntu 12.04 (Gnome-classic), by following this instructions. Problem started after giving these two commands dpkg -i kdelibs5-data_4.6.2-0ubuntu4_all.deb dpkg -i kdelibs-data_3.5.10.dfsg.1-5ubuntu2_all.deb Now, immediately after these commands, Ubuntu Updater popped up and gave me an error that the package catalog is broken and needs to be repaired. Nothing can be installed or removed till then. It also offered a suggestion to run apt-get install -f. I tried that, but again got the same error.Also tried apt-get clean followed by apt-get install -f. Again got the following output: jitesh@jitesh-desktop:~$ sudo apt-get clean jitesh@jitesh-desktop:~$ sudo apt-get install -f Reading package lists... Done Building dependency tree Reading state information... Done Correcting dependencies... Done The following extra packages will be installed: kdelibs5-data The following packages will be upgraded: kdelibs5-data 1 upgraded, 0 newly installed, 0 to remove and 18 not upgraded. 2 not fully installed or removed. Need to get 2,832 kB of archives. After this operation, 2,998 kB disk space will be freed. Do you want to continue [Y/n]? y Get:1 http: //in.archive.ubuntu.com/ubuntu/precise-updates/main kdelibs5-data all 4:4.8.4a-0ubuntu0.2 [2,832 kB] Fetched 2,832 kB in 32s (86.6 kB/s) dpkg: dependency problems prevent configuration of kdelibs5-data: libplasma3 (4:4.8.4a-0ubuntu0.2) breaks kdelibs5-data (<< 4:4.6.80~) and is installed. Version of kdelibs5-data to be configured is 4:4.6.2-0ubuntu4. kate-data (4:4.8.4-0ubuntu0.1) breaks kdelibs5-data (<< 4:4.6.90) and is installed. Version of kdelibs5-data to be configured is 4:4.6.2-0ubuntu4. katepart (4:4.8.4-0ubuntu0.1) breaks kdelibs5-data (<< 4:4.6.90) and is installed. Version of kdelibs5-data to be configured is 4:4.6.2-0ubuntu4. dpkg: error processing kdelibs5-data (--configure): dependency problems - leaving unconfigured dpkg: dependency problems prevent configuration of kdelibs-data: kdelibs-data depends on kdelibs5-data; however: Package kdelibs5-data is not configured yet. No apport report written because MaxReports is reached already dpkg: error processing kdelibs-data (--configure): dependency problems - leaving unconfigured No apport report written because MaxReports is reached already Errors were encountered while processing: kdelibs5-data kdelibs-data W: Duplicate sources.list entry http://archive.canonical.com/ubuntu/ precise/partner i386 Packages (/var/lib/apt/lists/archive.canonical.com_ubuntu_dists_precise_partner_binary-i386_Packages) W: You may want to run apt-get update to correct these problems E: Sub-process /usr/bin/dpkg returned an error code (1) As I thought the error was related to configuring kdelibs, I tried to configure using dpkg. But got the following errors: jitesh@jitesh-desktop:~$ sudo dpkg --configure -a dpkg: dependency problems prevent configuration of kdelibs5-data: libplasma3 (4:4.8.4a-0ubuntu0.2) breaks kdelibs5-data (<< 4:4.6.80~) and is installed. Version of kdelibs5-data to be configured is 4:4.6.2-0ubuntu4. kate-data (4:4.8.4-0ubuntu0.1) breaks kdelibs5-data (<< 4:4.6.90) and is installed. Version of kdelibs5-data to be configured is 4:4.6.2-0ubuntu4. katepart (4:4.8.4-0ubuntu0.1) breaks kdelibs5-data (<< 4:4.6.90) and is installed. Version of kdelibs5-data to be configured is 4:4.6.2-0ubuntu4. dpkg: error processing kdelibs5-data (--configure): dependency problems - leaving unconfigured dpkg: dependency problems prevent configuration of kdelibs-data: kdelibs-data depends on kdelibs5-data; however: Package kdelibs5-data is not configured yet. dpkg: error processing kdelibs-data (--configure): dependency problems - leaving unconfigured Errors were encountered while processing: kdelibs5-data kdelibs-data jitesh@jitesh-desktop:~$ Now I dont have any idea how to proceed. I am unable to install anything from Software Centre or using Terminal now. Some basic info: Core2Duo, dual booting Ubuntu 12.04 with Win7. Fresh install of Ubuntu 12.04 (not upgrade). Incidentally, I had first upgraded from 10.04 and had succesfully installed Amarok 1.4 following this same method. But due to other issues, i had to format and do a clean install of 12.04. Now when I tried to install Amarok 1.4, I'm getting these errors. I also have digiKam and k3b installed, if that can be of any help. I use digiKam a lot, so removing KDE is not feasible for me. Any help on this issue will be highly appreciated. Thanks in advance.

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• Source Control and SQL Development &ndash; Part 3

  - by Ajarn Mark Caldwell

  In parts one and two of this series, I have been specifically focusing on the latest version of SQL Source Control by Red Gate Software.  But I have been doing source-controlled SQL development for years, long before this product was available, and well before Microsoft came out with Database Projects for Visual Studio.  “So, how does that work?” you may wonder.  Well, let me share some of the details of how we do it where I work… The key to this approach is that everything is done via Transact-SQL script files; either natively written T-SQL, or generated.  My preference is to write all my code by hand, which forces you to become better at your SQL syntax.  But if you really prefer to use the Management Studio GUI to make database changes, you can still do that, and then you use the Generate Scripts feature of the GUI to produce T-SQL scripts afterwards, and store those in your source control system.  You can generate scripts for things like stored procedures and views by right-clicking on the database in the Object Explorer, and Choosing Tasks, Generate Scripts (see figure 1 to the left).  You can also do that for the CREATE scripts for tables, but that does not work when you have a table that is already in production, and you need to make just a simple change, such as adding a new column or index.  In this case, you can use the GUI to make the table changes, and then instead of clicking the Save button, click the Generate Change Script button (). Then, once you have saved the change script, go ahead and execute it on your development database to actually make the change.  I believe that it is important to actually execute the script rather than just click the Save button because this is your first test that your change script is working and you didn’t somehow lose a portion of the change. As you can imagine, all this generating of scripts can get tedious and tempting to skip entirely, so again, I would encourage you to just get in the habit of writing your own Transact-SQL code, and then it is just a matter of remembering to save your work, just like you are in the habit of saving changes to a Word or Excel document before you exit the program. So, now that you have all of these script files, what do you do with them?  Well, we organize ours into folders labeled ChangeScripts, Functions, Views, and StoredProcedures, and those folders are loaded into our source control system.  ChangeScripts contains all of the table and index changes, and anything else that is basically a one-time-only execution.  Of course you want to write your scripts with qualifying logic so that if a script were accidentally run more than once in a database, it would not crash nor corrupt anything; but these scripts are really intended to be run only once in a database. Once you have your initial set of scripts loaded into source control, then making changes, such as altering a stored procedure becomes a simple matter of checking out your CREATE PROCEDURE* script, editing it in SSMS, saving the change, executing the script in order to effect the change in your database, and then checking the script back in to source control.  Of course, this is where the lack of integration for source control systems within SSMS becomes an irritation, because this means that in addition to SSMS, I also have my source control client application running to do the check-out and check-in.  And when you have 800+ procedures like we do, that can be quite tedious to locate the procedure I want to change in source control, check it out, then locate the script file in my working folder, open it in SSMS, do the change, save it, and the go back to source control to check in.  Granted, it is not nearly as burdensome as, say, losing your source code and having to rebuild it from memory, or losing the audit trail that good source control systems provide.  It is worth the effort, and this is how I have been doing development for the last several years. Remember that everything that the SQL Server Management Studio does in modifying your database can also be done in plain Transact-SQL code, and this is what you are storing.  And now I have shown you how you can do it all without spending any extra money.  You already have source control, or can get free, open-source source control systems (almost seems like an oxymoron, doesn’t it) and of course Management Studio is free with your SQL Server database engine software. So, whether you spend the money on tools to make it easier, or not, you now have no excuse for not using source control with your SQL development. * In our current model, the scripts for stored procedures and similar database objects are written with an IF EXISTS…DROP… at the top, followed by the CREATE PROCEDURE… section, and that followed by a section that assigns permissions.  This allows me to run the same script regardless of whether the procedure previously existed in the database.  If the script was only an ALTER PROCEDURE, then it would fail the first time that procedure was deployed to a database, unless you wrote other code to stub it if it did not exist.  There are a few different ways you could organize your scripts for deployment, each with its own trade-offs, but I think it is absolutely critical that whichever way you organize things, you ensure that the same script is run throughout the deployment cycle, and do not allow customizations to creep in between TEST and PROD.  If you do, then you have broken the integrity of your deployment process because what you deployed to PROD was not exactly the same as what was tested in TEST, so you effectively have now released untested code into PROD.

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• Subterranean IL: Generics and array covariance

  - by Simon Cooper

  Arrays in .NET are curious beasts. They are the only built-in collection types in the CLR, and SZ-arrays (single dimension, zero-indexed) have their own commands and IL syntax. One of their stranger properties is they have a kind of built-in covariance long before generic variance was added in .NET 4. However, this causes a subtle but important problem with generics. First of all, we need to briefly recap on array covariance. SZ-array covariance To demonstrate, I'll tweak the classes I introduced in my previous posts: public class IncrementableClass { public int Value; public virtual void Increment(int incrementBy) { Value += incrementBy; } } public class IncrementableClassx2 : IncrementableClass { public override void Increment(int incrementBy) { base.Increment(incrementBy); base.Increment(incrementBy); } } In the CLR, SZ-arrays of reference types are implicitly convertible to arrays of the element's supertypes, all the way up to object (note that this does not apply to value types). That is, an instance of IncrementableClassx2[] can be used wherever a IncrementableClass[] or object[] is required. When an SZ-array could be used in this fashion, a run-time type check is performed when you try to insert an object into the array to make sure you're not trying to insert an instance of IncrementableClass into an IncrementableClassx2[]. This check means that the following code will compile fine but will fail at run-time: IncrementableClass[] array = new IncrementableClassx2[1]; array[0] = new IncrementableClass(); // throws ArrayTypeMismatchException These checks are enforced by the various stelem* and ldelem* il instructions in such a way as to ensure you can't insert a IncrementableClass into a IncrementableClassx2[]. For the rest of this post, however, I'm going to concentrate on the ldelema instruction. ldelema This instruction pops the array index (int32) and array reference (O) off the stack, and pushes a pointer (&) to the corresponding array element. However, unlike the ldelem instruction, the instruction's type argument must match the run-time array type exactly. This is because, once you've got a managed pointer, you can use that pointer to both load and store values in that array element using the ldind* and stind* (load/store indirect) instructions. As the same pointer can be used for both input and output to the array, the type argument to ldelema must be invariant. At the time, this was a perfectly reasonable restriction, and maintained array type-safety within managed code. However, along came generics, and with it the constrained callvirt instruction. So, what happens when we combine array covariance and constrained callvirt? .method public static void CallIncrementArrayValue() { // IncrementableClassx2[] arr = new IncrementableClassx2[1] ldc.i4.1 newarr IncrementableClassx2 // arr[0] = new IncrementableClassx2(); dup newobj instance void IncrementableClassx2::.ctor() ldc.i4.0 stelem.ref // IncrementArrayValue<IncrementableClass>(arr, 0) // here, we're treating an IncrementableClassx2[] as IncrementableClass[] dup ldc.i4.0 call void IncrementArrayValue<class IncrementableClass>(!!0[],int32) // ... ret } .method public static void IncrementArrayValue<(IncrementableClass) T>( !!T[] arr, int32 index) { // arr[index].Increment(1) ldarg.0 ldarg.1 ldelema !!T ldc.i4.1 constrained. !!T callvirt instance void IIncrementable::Increment(int32) ret } And the result: Unhandled Exception: System.ArrayTypeMismatchException: Attempted to access an element as a type incompatible with the array. at IncrementArrayValue[T](T[] arr, Int32 index) at CallIncrementArrayValue() Hmm. We're instantiating the generic method as IncrementArrayValue<IncrementableClass>, but passing in an IncrementableClassx2[], hence the ldelema instruction is failing as it's expecting an IncrementableClass[]. On features and feature conflicts What we've got here is a conflict between existing behaviour (ldelema ensuring type safety on covariant arrays) and new behaviour (managed pointers to object references used for every constrained callvirt on generic type instances). And, although this is an edge case, there is no general workaround. The generic method could be hidden behind several layers of assemblies, wrappers and interfaces that make it a requirement to use array covariance when calling the generic method. Furthermore, this will only fail at runtime, whereas compile-time safety is what generics were designed for! The solution is the readonly. prefix instruction. This modifies the ldelema instruction to ignore the exact type check for arrays of reference types, and so it lets us take the address of array elements using a covariant type to the actual run-time type of the array: .method public static void IncrementArrayValue<(IncrementableClass) T>( !!T[] arr, int32 index) { // arr[index].Increment(1) ldarg.0 ldarg.1 readonly. ldelema !!T ldc.i4.1 constrained. !!T callvirt instance void IIncrementable::Increment(int32) ret } But what about type safety? In return for ignoring the type check, the resulting controlled mutability pointer can only be used in the following situations: As the object parameter to ldfld, ldflda, stfld, call and constrained callvirt instructions As the pointer parameter to ldobj or ldind* As the source parameter to cpobj In other words, the only operations allowed are those that read from the pointer; stind* and similar that alter the pointer itself are banned. This ensures that the array element we're pointing to won't be changed to anything untoward, and so type safety within the array is maintained. This is a typical example of the maxim that whenever you add a feature to a program, you have to consider how that feature interacts with every single one of the existing features. Although an edge case, the readonly. prefix instruction ensures that generics and array covariance work together and that compile-time type safety is maintained. Tune in next time for a look at the .ctor generic type constraint, and what it means.

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• Using Transaction Logging to Recover Post-Archived Essbase data

  - by Keith Rosenthal

  Data recovery is typically performed by restoring data from an archive.  Data added or removed since the last archive took place can also be recovered by enabling transaction logging in Essbase.  Transaction logging works by writing transactions to a log store.  The information in the log store can then be recovered by replaying the log store entries in sequence since the last archive took place.  The following information is recorded within a transaction log entry: Sequence ID Username Start Time End Time Request Type A request type can be one of the following categories: Calculations, including the default calculation as well as both server and client side calculations Data loads, including data imports as well as data loaded using a load rule Data clears as well as outline resets Locking and sending data from SmartView and the Spreadsheet Add-In.  Changes from Planning web forms are also tracked since a lock and send operation occurs during this process. You can use the Display Transactions command in the EAS console or the query database MAXL command to view the transaction log entries. Enabling Transaction Logging Transaction logging can be enabled at the Essbase server, application or database level by adding the TRANSACTIONLOGLOCATION essbase.cfg setting.  The following is the TRANSACTIONLOGLOCATION syntax: TRANSACTIONLOGLOCATION [appname [dbname]] LOGLOCATION NATIVE ENABLE | DISABLE Note that you can have multiple TRANSACTIONLOGLOCATION entries in the essbase.cfg file.  For example: TRANSACTIONLOGLOCATION Hyperion/trlog NATIVE ENABLE TRANSACTIONLOGLOCATION Sample Hyperion/trlog NATIVE DISABLE The first statement will enable transaction logging for all Essbase applications, and the second statement will disable transaction logging for the Sample application.  As a result, transaction logging will be enabled for all applications except the Sample application. A location on a physical disk other than the disk where ARBORPATH or the disk files reside is recommended to optimize overall Essbase performance. Configuring Transaction Log Replay Although transaction log entries are stored based on the LOGLOCATION parameter of the TRANSACTIONLOGLOCATION essbase.cfg setting, copies of data load and rules files are stored in the ARBORPATH/app/appname/dbname/Replay directory to optimize the performance of replaying logged transactions.  The default is to archive client data loads, but this configuration setting can be used to archive server data loads (including SQL server data loads) or both client and server data loads. To change the type of data to be archived, add the TRANSACTIONLOGDATALOADARCHIVE configuration setting to the essbase.cfg file.  Note that you can have multiple TRANSACTIONLOGDATALOADARCHIVE entries in the essbase.cfg file to adjust settings for individual applications and databases. Replaying the Transaction Log and Transaction Log Security Considerations To replay the transactions, use either the Replay Transactions command in the EAS console or the alter database MAXL command using the replay transactions grammar.  Transactions can be replayed either after a specified log time or using a range of transaction sequence IDs. The default when replaying transactions is to use the security settings of the user who originally performed the transaction.  However, if that user no longer exists or that user's username was changed, the replay operation will fail. Instead of using the default security setting, add the REPLAYSECURITYOPTION essbase.cfg setting to use the security settings of the administrator who performs the replay operation.  REPLAYSECURITYOPTION 2 will explicitly use the security settings of the administrator performing the replay operation.  REPLAYSECURITYOPTION 3 will use the administrator security settings if the original user’s security settings cannot be used. Removing Transaction Logs and Archived Replay Data Load and Rules Files Transaction logs and archived replay data load and rules files are not automatically removed and are only removed manually.  Since these files can consume a considerable amount of space, the files should be removed on a periodic basis. The transaction logs should be removed one database at a time instead of all databases simultaneously.  The data load and rules files associated with the replayed transactions should be removed in chronological order from earliest to latest.  In addition, do not remove any data load and rules files with a timestamp later than the timestamp of the most recent archive file. Partitioned Database Considerations For partitioned databases, partition commands such as synchronization commands cannot be replayed.  When recovering data, the partition changes must be replayed manually and logged transactions must be replayed in the correct chronological order. If the partitioned database includes any @XREF commands in the calc script, the logged transactions must be selectively replayed in the correct chronological order between the source and target databases. References For additional information, please see the Oracle EPM System Backup and Recovery Guide.  For EPM 11.1.2.2, the link is http://docs.oracle.com/cd/E17236_01/epm.1112/epm_backup_recovery_1112200.pdf

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• Binding a property to change the listbox items foreground individually for each item

  - by Eyal-Shilony

  I'm trying to change the foreground color of the items in the ListBox individually for each item, I've already posted a similar question but this one is more concrete. I hoped that the state of the color is reserved for each item added to the ListBox, so I tried to create a property (in this case "HotkeysForeground"), bind it and change the color when the items are added in the "HotkeyManager_NewHotkey" event, the problem it's changing the foreground color for all the items in the ListBox. How can I do that per item ? Here is the ViewModel I use. namespace Monkey.Core.ViewModel { using System; using System.Collections.ObjectModel; using System.Windows.Media; using Monkey.Core.SystemMonitor.Accessibility; using Monkey.Core.SystemMonitor.Input; public class MainWindowViewModel : WorkspaceViewModel { private readonly FocusManager _focusManager; private readonly HotkeyManager _hotkeyManager; private readonly ObservableCollection<string> _hotkeys; private Color _foregroundColor; private string _title; public MainWindowViewModel() { _hotkeys = new ObservableCollection<string>(); _hotkeyManager = new HotkeyManager(); _hotkeyManager.NewHotkey += HotkeyManager_NewHotkey; _focusManager = new FocusManager(); _focusManager.Focus += FocusManager_Focus; } public Color HotkeysForeground { get { return _foregroundColor; } set { _foregroundColor = value; OnPropertyChanged(() => HotkeysForeground); } } public ReadOnlyObservableCollection<string> Hotkeys { get { return new ReadOnlyObservableCollection<string>(_hotkeys); } } public string Title { get { return _title; } set { _title = value; OnPropertyChanged(() => Title); } } protected override void OnDispose() { base.OnDispose(); _hotkeyManager.Dispose(); _focusManager.Dispose(); } private void FocusManager_Focus(object sender, FocusManagerEventArgs e) { Title = e.Title; } private void HotkeyManager_NewHotkey(object sender, EventArgs eventArgs) { HotkeysForeground = _hotkeys.Count <= 2 ? Colors.Blue : Colors.Brown; _hotkeys.Clear(); foreach (var hotkey in _hotkeyManager.GetHotkeys()) { _hotkeys.Add(hotkey); } } } } Here is the view. <Window x:Class="Monkey.View.MainWindow" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" xmlns:System="clr-namespace:System;assembly=mscorlib" Title="{Binding Mode=OneWay, Path=Title, UpdateSourceTrigger=PropertyChanged}" Height="200" Width="200" ShowInTaskbar="False" WindowStyle="ToolWindow" Topmost="True" ResizeMode="CanResizeWithGrip" AllowsTransparency="False"> <Window.Resources> <SolidColorBrush Color="{Binding HotkeysForeground}" x:Key="HotkeysBrush"/> </Window.Resources> <ListBox Canvas.Left="110" Canvas.Top="74" Name="HotkeyList" Height="Auto" Width="Auto" HorizontalContentAlignment="Left" BorderThickness="0" ScrollViewer.CanContentScroll="False" ScrollViewer.HorizontalScrollBarVisibility="Disabled" ScrollViewer.VerticalScrollBarVisibility="Disabled" ItemsSource="{Binding Path=Hotkeys}" VerticalAlignment="Stretch" VerticalContentAlignment="Center" FontSize="20"> <ListBox.ItemContainerStyle> <Style TargetType="ListBoxItem"> <Setter Property="IsEnabled" Value="False" /> </Style> </ListBox.ItemContainerStyle> <ListBox.ItemTemplate> <DataTemplate> <Label Content="{Binding}" Foreground="{StaticResource HotkeysBrush}"/> </DataTemplate> </ListBox.ItemTemplate> </ListBox> </Window> Thank you in advance.

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• Application Development: Python or Java (or PHP)

  - by luckysmack

  I'm looking to get into application development, such as Facebook or Android apps and games. I am doing this for fun and to learn. Once my skills are to par I would like to have some side income from the apps, but I'm not banking on living off that (just so you know where I'm coming from and know what my end goals are). Currently I know and am familiar with PHP and frameworks such as cakephp and yii. However, I have been wanting to learn another language to broaden my horizons and to become a better developer. So I have narrowed it down to 2 languages. Python, and Java (I can already hear people cringing at the difference in the languages I have chosen, but I have some reasons). Python: closer to PHP that Java. Cross platformability. Also great as a general scripting language and has many file system level benefits that PHP does not. Cleaner syntax, readability, blah blah and the list goed on. Python will work great for cross platform apps and can be run on many OS's and is supported by Facebook for app development. But there is no support on Android (for full fledged apps). Java: a much stronger typed language, very robust community and corporate backing. Knowing Java is also good for personal marketability for enterprises, if you're into that. The main benefit here is that Java can write apps natively for Android and the apps can be ported for web versions to play on Facebook. So while I have seen many developers prefer Java over the two, Java has this significant advantage, where I can market my apps in both markets and in the future build more potential income. But like I said it is for fun. While money isn't the goal, it would still be nice. PHP: I'm putting this here because I know it already, and I'm sure a case could be made for it. It obviously works great for Facebook but like Python does not do so well on android. While it's mostly the realm of 'application development' that appeals to me, I do find Android apps fairly interesting and something that has a ton of potential to. But then again Facebook has a ton more users and the apps can also potentially be more immersive (desktop vs. mobile). So this is why I'm kinda stuck on what route to choose. Python for Facebook and web apps, with likely faster development to production times, or Java which can be developed for any of the platforms to make apps. Side note: I'm not really trying to get into 3D development, mostly 2D. And I also want to make an app with real-time play (websockets, etc). Someone mentioned node, js to me for that but Python seems to be more globally versatile for my goals. So, to anyone that does Facebook or Android development in either language: what do you suggest? Any input is valuable and I do appreciate it. And sorry for being long winded. EDIT: as mentioned in one of the answers, my primary goal is gaming. Although I do have some plans for non gaming apps such as general web based and desktop based ones. But gaming is my main goal with the possibility of income. EDIT: Another consideration could be Jython. Writing Python code which is converted into Java bytecode. This would allow the ability to do Android apps using Python. I could be wrong though, I'm still looking into it. Update 1-26-11: I recently acquired a new job which required I learn .NET using C#. Im sure some of you are cringing already but I really like the whole system and how it all works together between desktop and web development. But, as I am still interested in Python very much, and after some research I have decided I will learn Python as well as the IronPython implementation for .NET. But (again: I know...) since .NET is mostly a Windows thing and not as cross-compatible as I like, I will be learning Mono which is a cross platform implementation of .NET where I can use what I learn at work using C# and what I want to learn, Python/IronPython. So while learning and writing C#/.NET @ work I will be learning Python - Mono - Iron Python for what I want to do personally. And the benefit of them all being very closely related will help me out a lot, I think. What do you guys think? I almost feel like that should be another question, but there's not much of a question. Either way, you guys gave very helpful input.

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• Converting LINQ to Twitter to Twitter API v1.1

  - by Joe Mayo

  Twitter recently updated their API to v1.1 (Current status: API v1.1). Naturally, LINQ to Twitter  needed to be updated too. This blog post outlines the changes made to LINQ to Twitter during this conversion and highlights important features that LINQ to Twitter developers will want to know. Overall Impact Generally speaking, Twitter API v1.1 is semantically very much the same as it’s predecessor. The base URL changed and so did a few resource segments, but the resources themselves are still intact. The good news is that LINQ to Twitter has always shielded the developer from this plumbing, so the entities, types, and filters didn’t change much at all.  The following sections describe what did  change. Authentication In Twitter API v1.0 authentication was not required for some resources, such as user timelines and search. However, that’s all changed because *all* queries must be authenticated in Twitter API v1.1. LINQ to Twitter has various types of authorizers you can use, supporting whatever OAuth options are available via Twitter.  You can see the LINQ to Twitter documentation, Securing Your Applications, for more info on OAuth support. The New Search One of the larger changes to the API was Search. To be more specific, the Search entity now contains a List<Status>, named Statuses, to hold results.  Additionally, any meta-data associated with the search is now in a property named SearchMetaData. The change to the Search entity and responses is the big change, but the good news is that your Search query syntax doesn’t change. Different Rate Limits The issue of rate limits itself is contentious, but this discussion is focused on the coding experience and I’ll leave the politics to those who prefer to engage in that activity. What’s important here is that both headers and resources have changed. You should review Twitter’s Rate Limit documentation to understand what the changes mean.  A quick explanation is that rate limits are applied individually to each resource in 15 minute time intervals. In LINQ to Twitter these changes surface on the Help entity, via HelpType.RateLimits. The RateLimits query has a Resources filter where you can specify a comma-separated list of categories to return rate limit info for.  The results materialize in the RateLimits dictionary, keyed on category. The Help entity also has a RateLimitsAuthorizationContext, holding the Access Token for the user performing queries – and to whom the rate limits apply. In addition to the new RateLimits query, there are new RateLimit headers that appear in the query response, whose HTTP header name is of the form X-Rate-Limit… which is different from the previous header name. LINQ to Twitter surfaces these headers via the existing properties of the TwitterContext instance. For anyone who retrieved rate limit information via the Headers property of TwitterContext, you should be aware of the new header names.  I haven’t done anything with Feature rate limit properties yet, but they appear to no longer be available – this will require more follow-up. Error Handling Twitter API v1.1 has a new format for Error Codes & Responses. LINQ to Twitter wraps these messages in the TwitterQueryException, which has been updated appropriately. The Message property of TwitterQueryException now reflects the Twitter error message, when available. There’s also a new ErrorCode that’s populated with the message error code. Parameters Most parameters stayed the same, but one of interest is Include Entities (different from LINQ to Twitter data object entities). Entities are metadata hanging off tweets, that provide start/end position in the tweet and other information for mentions, urls, hash tags, and media. Entities used to not be included unless you specified you wanted them. Now, in v1.1, entities are included by default for all APIs that return a Status.  If you were always setting IncludeEntities to true, then you won’t see a change. However, be aware that you’ll now be receiving additional data in your response from Twitter, which will explain a sudden increase in bandwidth utilization. This might or might not  matter to you  depending on the requirements of your application, but you should be aware of it. Everything Else There might be small changes here and there that I haven’t mentioned, but these were the ones you should be most aware of.  Streams didn’t change, but Twitter will be deprecating username/password authentication on public streams, in favor of OAuth, so you’ll be seeing me make that change some time in the future.  Also, Twitter will continue to evolve the API and you can expect that LINQ to Twitter will change accordingly. Summary The big changes to Twitter API were Authentication, Search, Rate Limits, and Error Handling. All API calls must be authenticated. You’ll need to change your code to read Search results differently, but the query is much the same as you use now. There’s a new RateLimits API, one of the Help queries.  Also, the new error messages are integrated into TwitterQueryException. Besides these changes, I expect  most others to be small or affect a smaller percentage of developers.  You can get the latest version of LINQ to Twitter from NuGet or visit the LINQ to Twitter download page at CodePlex.com.   @JoeMayo

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• Custom Configuration Section Handlers

  Most .NET developers who need to store something in configuration tend to use appSettings for this purpose, in my experience.  More recently, the framework itself has helped things by adding the <connectionStrings /> section so at least these are in their own section and not adding to the appSettings clutter that pollutes most apps.  I recommend avoiding appSettings for several reasons.  In addition to those listed there, I would add that strong typing and validation are additional reasons to go the custom configuration section route. For my ASP.NET Tips and Tricks talk, I use the following example, which is a simple DemoSettings class that includes two fields.  The first is an integer representing how many attendees there are present for the talk, and the second is the title of the talk.  The setup in web.config is as follows: <configSections> <section name="DemoSettings" type="ASPNETTipsAndTricks.Code.DemoSettings" /> </configSections>   <DemoSettings sessionAttendees="100" title="ASP.NET Tips and Tricks DevConnections Spring 2010" /> Referencing the values in code is strongly typed and straightforward.  Here I have a page that exposes two properties which internally get their values from the configuration section handler: public partial class CustomConfig1 : System.Web.UI.Page { public string SessionTitle { get { return DemoSettings.Settings.Title; } } public int SessionAttendees { get { return DemoSettings.Settings.SessionAttendees; } } } Note that the settings are only read from the config file once after that they are cached so there is no need to be concerned about excessive file access. Now weve seen how to set it up on the config file and how to refer to the settings in code.  All that remains is to see the file itself: public class DemoSettings : ConfigurationSection { private static DemoSettings settings = ConfigurationManager.GetSection("DemoSettings") as DemoSettings; public static DemoSettings Settings{ get { return settings;} }   [ConfigurationProperty("sessionAttendees" , DefaultValue = 200 , IsRequired = false)] [IntegerValidator(MinValue = 1 , MaxValue = 10000)] public int SessionAttendees { get { return (int)this["sessionAttendees"]; } set { this["sessionAttendees"] = value; } }   [ConfigurationProperty("title" , IsRequired = true)] [StringValidator(InvalidCharacters = "~!@#$%^&*()[]{}/;\"|\\")] public string Title { get { return (string)this["title"]; } set { this["title"] = value; }   } } The class is pretty straightforward, but there are some important components to note.  First, it must inherit from System.Configuration.ConfigurationSection.  Next, as a convention I like to have a static settings member that is responsible for pulling out the section when the class is first referenced, and further to expose this collection via a static readonly property, Settings.  Note that the types of both of these are the type of my class, DemoSettings. The properties of the class, SessionAttendees and Title, should map to the attributes of the config element in the XML file.  The [ConfigurationProperty] attribute allows you to map the attribute name to the property name (thus using both XML standard naming conventions and C# naming conventions).  In addition, you can specify a default value to use if nothing is specified in the config file, and whether or not the setting must be provided (IsRequired).  If it is required, then it doesnt make sense to include a default value. Beyond defaults and required, you can specify more advanced validation rules for the configuration values using additional C# attributes, such as [IntegerValidator] and [StringValidator].  Using these, you can declaratively specify that your configuration values be in a given range, or omit certain forbidden characters, for instance.  Of course you can write your own custom validation attributes, and there are others specified in System.Configuration. Individual sections can also be loaded from separate files, using syntax like this: <DemoSettings configSource="demosettings.config" /> Summary Using a custom configuration section handler is not hard.  If your application or component requires configuration, I recommend creating a custom configuration handler dedicated to your app or component.  Doing so will reduce the clutter in appSettings, will provide you with strong typing and validation, and will make it much easier for other developers or system administrators to locate and understand the various configuration values that are necessary for a given application. Did you know that DotNetSlackers also publishes .net articles written by top known .net Authors? We already have over 80 articles in several categories including Silverlight. Take a look: here.

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• Five development tools I can't live without

  - by bconlon

  When applying to join Geeks with Blogs I had to specify the development tools I use every day. That got me thinking, it's taken a long time to whittle my tools of choice down to the selection I use, so it might be worth sharing. Before I begin, I appreciate we all have our preferred development tools, but these are the ones that work for me. Microsoft Visual Studio Microsoft Visual Studio has been my development tool of choice for more years than I care to remember. I first used this when it was Visual C++ 1.5 (hats off to those who started on 1.0) and by 2.2 it had everything I needed from a C++ IDE. Versions 4 and 5 followed and if I had to guess I would expect more Windows applications are written in VC++ 6 and VB6 than any other language. Then came the not so great versions Visual Studio .Net 2002 (7.0) and 2003 (7.1). If I'm honest I was still using v6. 2005 was better and 2008 was simply brilliant. Everything worked, the compiler was super fast and I was happy again...then came 2010...oh dear. 2010 is a big step backwards for me. It's not encouraging for my upcoming WPF exploits that 2010 is fronted in WPF technology, with the forever growing Find/Replace dialog, the issues with C++ intellisense, and the buggy debugger. That said it is still my tool of choice but I hope they sort the issue in SP1. I've tried other IDEs like Visual Age and Eclipse, but for me Visual Studio is the best. A really great tool. Liquid XML Studio XML development is a tricky business. The W3C standards are often difficult to get to the bottom of so it's great to have a graphical tool to help. I first used Liquid Technologies 5 or 6 years back when I needed to process XML data in C++. Their excellent XML Data Binding tool has an easy to use Wizard UI (as compared to Castor or JAXB command line tools) and allows you to generate code from an XML Schema. So instead of having to deal with untyped nodes like with a DOM parser, instead you get an Object Model providing a custom API in C++, C#, VB etc. More recently they developed a graphical XML IDE with XML Editor, XSLT, XQuery debugger and other XML tools. So now I can develop an XML Schema graphically, click a button to generate a Sample XML document, and click another button to run the Wizard to generate code including a Sample Application that will then load my Sample XML document into the generated object model. This is a very cool toolset. Note: XML Data Binding is nothing to do with WPF Data Binding, but I hope to cover both in more detail another time. .Net Reflector Note: I've just noticed that starting form the end of February 2011 this will no longer be a free tool !! .Net Reflector turns .Net byte code back into C# source code. But how can it work this magic? Well the clue is in the name, it uses reflection to inspect a compiled .Net assembly. The assembly is compiled to byte code, it doesn't get compiled to native machine code until its needed using a just-in-time (JIT) compiler. The byte code still has all of the information needed to see classes, variables. methods and properties, so reflector gathers this information and puts it in a handy tree. I have used .Net Reflector for years in order to understand what the .Net Framework is doing as it sometimes has undocumented, quirky features. This really has been invaluable in certain instances and I cannot praise enough kudos on the original developer Lutz Roeder. Smart Assembly In order to stop nosy geeks looking at our code using a tool like .Net Reflector, we need to obfuscate (mess up) the byte code. Smart Assembly is a tool that does this. Again I have used this for a long time. It is very quick and easy to use. Another excellent tool. Coincidentally, .Net Reflector and Smart Assembly are now both owned by Red Gate. Again kudos goes to the original developer Jean-Sebastien Lange. TortoiseSVN SVN (Apache Subversion) is a Source Control System developed as an open source project. TortoiseSVN is a graphical UI wrapper over SVN that hooks into Windows Explorer to enable files to be Updated, Committed, Merged etc. from the right click menu. This is an essential tool for keeping my hard work safe! Many years ago I used Microsoft Source Safe and I disliked CVS type systems. But TortoiseSVN is simply the best source control tool I have ever used. --- So there you have it, my top 5 development tools that I use (nearly) every day and have helped to make my working life a little easier. I'm sure there are other great tools that I wish I used but have never heard of, but if you have not used any of the above, I would suggest you check them out as they are all very, very cool products. #

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• CodePlex Daily Summary for Tuesday, July 30, 2013

  CodePlex Daily Summary for Tuesday, July 30, 2013Popular ReleasesnopCommerce. Open source shopping cart (ASP.NET MVC): nopCommerce 3.10: Highlight features & improvements: • Performance optimization. • New more user-friendly product/product-variant logic. Now we'll have only products (simple and grouped). • Bundle products support added. • Allow a store owner to associate product image for product variant attribute values. To see the full list of fixes and changes please visit the release notes page (http://www.nopCommerce.com/releasenotes.aspx).Small Tools: Helpers 1.01: Fix params count issue Fix STAThread issue Add support for exe.config filesExtJS based ASP.NET Controls: FineUI v3.3.1: ??FineUI ?? ExtJS ??? ASP.NET ???。 FineUI??? ?? No JavaScript，No CSS，No UpdatePanel，No ViewState，No WebServices ???????。 ?????? IE 7.0、Firefox 3.6、Chrome 3.0、Opera 10.5、Safari 3.0+ ???? Apache License v2.0 ?：ExtJS ?? GPL v3 ?????(http://www.sencha.com/license)。 ???? ??：http://fineui.com/bbs/ ??：http://fineui.com/demo/ ??：http://fineui.com/doc/ ??：http://fineui.codeplex.com/ FineUI ???? ExtJS ????????，???? ExtJS ?，???????????ExtJS?： 1. ????? FineUI ? ExtJS ?：http://fineui.com/bbs/fo...AutoNLayered - Domain Oriented N-Layered .NET 4.5: AutoNLayered v1.0.5: - Fix Dtos. Abstract collections replaced by concrete (correct serialization WCF). - OrderBy in navigation properties. - Unit Test with Fakes. - Map of entities/dto moved to application services. - Libraries updated. Warning using Fakes: http://connect.microsoft.com/VisualStudio/feedback/details/782031/visual-studio-2012-add-fakes-assembly-does-not-add-all-needed-referencesPath Copy Copy: 11.1: Minor release with two new features: Submenu's contextual menu item now has an icon next to it Added reference to JavaScript regular expression format in Settings application Since this release does not have any glaring bug fixes, it is more of an optional update for existing users. It depends on whether you want to be able to spot the Path Copy Copy submenu more easily. I recommend you install it to see if the icon makes sense. As always, please don't hesitate to leave feedback via Discus...CMake Tools for Visual Studio: CMake Tools for Visual Studio 1.0 RC3: This is the third release candidate of CMake Tools for Visual Studio 1.0, which contains the following bug fixes: Opening a CMake file from Windows Explorer while Visual Studio is already open will no start a new instance of Visual Studio. Typing a symbol while the IntelliSense list box is visible and the text typed so far does not match any item in the list will dismiss the list box and insert the symbol typed.R.NET: R.NET 1.5: The major changes in v1.5 are: Initialize method must be called before using R. Settings should be passed to the method. EagerEvaluate method renamed to Evaluate (use Defer method when you want old version of Evaluate).Media Companion: Media Companion MC3.574b: Some good bug fixes been going on with the new XBMC-Link function. Thanks to all who were able to do testing and gave feedback. New:* Added some adhoc extra General movie filters, one of which is Plot = Outline (see fixes above). To see the filters, add the following line to your config.xml: <ShowExtraMovieFilters>True</ShowExtraMovieFilters>. The others are: Imdb in folder name, Imdb in not folder name & Imdb not in folder name & year mismatch. * Movie - display <tag> list on browser tab ...OfflineBrowser: Preview Release with Search: I've added search to this release.VG-Ripper & PG-Ripper: VG-Ripper 2.9.46: changes FIXED LoginMath.NET Numerics: Math.NET Numerics v2.6.0: What's New in Math.NET Numerics 2.6 - Announcement, Explanations and Sample Code. New: Linear Curve Fitting Linear least-squares fitting (regression) to lines, polynomials and linear combinations of arbitrary functions. Multi-dimensional fitting. Also works well in F# with the F# extensions. New: Root Finding Brent's method. ~Candy Chiu, Alexander Täschner Bisection method. ~Scott Stephens, Alexander Täschner Broyden's method, for multi-dimensional functions. ~Alexander Täschner ...AJAX Control Toolkit: July 2013 Release: AJAX Control Toolkit Release Notes - July 2013 Release Version 7.0725July 2013 release of the AJAX Control Toolkit. AJAX Control Toolkit .NET 4.5 – AJAX Control Toolkit for .NET 4.5 and sample site (Recommended). AJAX Control Toolkit .NET 4 – AJAX Control Toolkit for .NET 4 and sample site (Recommended). AJAX Control Toolkit .NET 3.5 – AJAX Control Toolkit for .NET 3.5 and sample site (Recommended). Notes: - Instructions for using the AJAX Control Toolkit with ASP.NET 4.5 can be found at...MJP's DirectX 11 Samples: Specular Antialiasing Sample: Sample code to complement my presentation that's part of the Physically Based Shading in Theory and Practice course at SIGGRAPH 2013, entitled "Crafting a Next-Gen Material Pipeline for The Order: 1886". Demonstrates various methods of preventing aliasing from specular BRDF's when using high-frequency normal maps. The zip file contains source code as well as a pre-compiled x64 binary.EXCEL??、??、????????：DataPie（??MSSQL 2008、ORACLE、ACCESS 2007）: DataPieV3.6.1: ????csv????，???sql??，??csv????Qibla Compass for Windows Phone: Qibla Compass for Windows Phone: This release is in open beta version. You can always download and provide your feedback. Since it was just developed to give users an idea of Qibla Direction and its mapping therefore you might not see major releases in future.Event Scavenger: Version 5: I've decided to do a full (recommended) release of version 5. I've been running it myself for months and did not have any issues with it yet. This release just contains the installs. The web site's documentation has not been updated yet and reflects the previous version details. If you have an issue with this version then you can happily switch back to 4.x. Version 5 can run side-by-side with earlier versions (service) as it has a new service and database.wpadk: WPadk_WP8???: ???：V1.1 ??wp???????????????wp8???????StockSharp: StockSharp 4.1.16: ?????? ????????? - http://stocksharp.com/forum/yaf_postsm28239_S--API-4-1.aspx#post28239GeoTransformer: GeoTransformer 4.5: Extensions can now be installed and uninstalled from the application. The extensions update the same way as the application - silently and automatically. Added ability to search for caches by pressing CTRL+F in the table views. (Thanks to JanisU for implementing this request) Added ability to remove edited customizations for multiple caches at once (use SHIFT or CTRL to select multiple lines in the table). A new experimental version for Windows 8 RT (on ARM processor) is also made availa...Kartris E-commerce: Kartris v2.5003: This fixes an issue where search engines appear to identify as IE and so trigger the noIE page if there is not a non-responsive skin specified.New ProjectsBus Booking System: Bus Booking systemC#??????: ????C#??????????????。Cotizav 2.0: Este proyecto es para el soporte de Cotizaciones.DeferredShading: deferred shading rendererIVR Junction: IVR Junction connects an Interactive Voice Response (IVR) system to cloud services such as YouTube, Facebook and other social media.Mac Address Changer: It's a quite and easy tool to change your mac addressmotokraft user control: user control for motokraftSingle Reference JavaScript Pattern: This is very simple pattern. In here you need to only refer one script in a page. I'm sure it is saving your development time as well as maintenance timeSocial_Life_Time: This is social network that people can communicate with each otherThe Ironic Text Based MMORPG: Modern MMORPGs have become highly interactive, complex systems of skills, stats, and action combat. This game introduces a new level of text based immersion!Timeline Year Control: Timeline Year Control An ASP.Net year indicator timeline control.winrtsock: winsock façade for Windows Runtime for porting bsd socket code to Windows RuntimeZker: No summary?????: C#?????

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• Dynamically specify the type in C#

  - by Lirik

  I'm creating a custom DataSet and I'm under some constrains: I want the user to specify the type of the data which they want to store. I want to reduce type-casting because I think it will be VERY expensive. I will use the data VERY frequently in my application. I don't know what type of data will be stored in the DataSet, so my initial idea was to make it a List of objects, but I suspect that the frequent use of the data and the need to type-cast will be very expensive. The basic idea is this: class DataSet : IDataSet { private Dictionary<string, List<Object>> _data; /// <summary> /// Constructs the data set given the user-specified labels. /// </summary> /// <param name="labels"> /// The labels of each column in the data set. /// </param> public DataSet(List<string> labels) { _data = new Dictionary<string, List<object>>(); foreach (string label in labels) { _data.Add(label, new List<object>()); } } #region IDataSet Members public List<string> DataLabels { get { return _data.Keys.ToList(); } } public int Count { get { _data[_data.Keys[0]].Count; } } public List<object> GetValues(string label) { return _data[label]; } public object GetValue(string label, int index) { return _data[label][index]; } public void InsertValue(string label, object value) { _data[label].Insert(0, value); } public void AddValue(string label, object value) { _data[label].Add(value); } #endregion } A concrete example where the DataSet will be used is to store data obtained from a CSV file where the first column contains the labels. When the data is being loaded from the CSV file I'd like to specify the type rather than casting to object. The data could contain columns such as dates, numbers, strings, etc. Here is what it could look like: "Date","Song","Rating","AvgRating","User" "02/03/2010","Code Monkey",4.6,4.1,"joe" "05/27/2009","Code Monkey",1.2,4.5,"jill" The data will be used in a Machine Learning/Artificial Intelligence algorithm, so it is essential that I make the reading of data very fast. I want to eliminate type-casting as much as possible, since I can't afford to cast from 'object' to whatever data type is needed on every read. I've seen applications that allow the user to pick the specific data type for each item in the csv file, so I'm trying to make a similar solution where a different type can be specified for each column. I want to create a generic solution so I don't have to return a List<object> but a List<DateTime> (if it's a DateTime column) or List<double> (if it's a column of doubles). Is there any way that this can be achieved? Perhaps my approach is wrong, is there a better approach to this problem?

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• YouTube Scalability Lessons

  - by Bertrand Matthelié

  @font-face { font-family: "Arial"; }@font-face { font-family: "Courier New"; }@font-face { font-family: "Wingdings"; }@font-face { font-family: "Calibri"; }@font-face { font-family: "Cambria"; }p.MsoNormal, li.MsoNormal, div.MsoNormal { margin: 0cm 0cm 0.0001pt; font-size: 12pt; font-family: "Times New Roman"; }h2 { margin: 12pt 0cm 3pt; page-break-after: avoid; font-size: 14pt; font-family: "Times New Roman"; font-style: italic; }a:link, span.MsoHyperlink { color: blue; text-decoration: underline; }a:visited, span.MsoHyperlinkFollowed { color: purple; text-decoration: underline; }span.Heading2Char { font-family: Calibri; font-weight: bold; font-style: italic; }div.Section1 { page: Section1; }ol { margin-bottom: 0cm; }ul { margin-bottom: 0cm; } Very interesting blog post by Todd Hoff at highscalability.com presenting “7 Years of YouTube Scalability Lessons in 30 min” based on a presentation from Mike Solomon, one of the original engineers at YouTube: …. The key takeaway away of the talk for me was doing a lot with really simple tools. While many teams are moving on to more complex ecosystems, YouTube really does keep it simple. They program primarily in Python, use MySQL as their database, they’ve stuck with Apache, and even new features for such a massive site start as a very simple Python program. That doesn’t mean YouTube doesn’t do cool stuff, they do, but what makes everything work together is more a philosophy or a way of doing things than technological hocus pocus. What made YouTube into one of the world’s largest websites? Read on and see... Stats @font-face { font-family: "Arial"; }@font-face { font-family: "Cambria"; }p.MsoNormal, li.MsoNormal, div.MsoNormal { margin: 0cm 0cm 0.0001pt; font-size: 12pt; font-family: "Times New Roman"; }div.Section1 { page: Section1; } 4 billion Views a day 60 hours of video is uploaded every minute 350+ million devices are YouTube enabled Revenue double in 2010 The number of videos has gone up 9 orders of magnitude and the number of developers has only gone up two orders of magnitude. 1 million lines of Python code Stack @font-face { font-family: "Arial"; }@font-face { font-family: "Cambria"; }p.MsoNormal, li.MsoNormal, div.MsoNormal { margin: 0cm 0cm 0.0001pt; font-size: 12pt; font-family: "Times New Roman"; }div.Section1 { page: Section1; } Python - most of the lines of code for YouTube are still in Python. Everytime you watch a YouTube video you are executing a bunch of Python code. Apache - when you think you need to get rid of it, you don’t. Apache is a real rockstar technology at YouTube because they keep it simple. Every request goes through Apache. Linux - the benefit of Linux is there’s always a way to get in and see how your system is behaving. No matter how bad your app is behaving, you can take a look at it with Linux tools like strace and tcpdump. MySQL - is used a lot. When you watch a video you are getting data from MySQL. Sometime it’s used a relational database or a blob store. It’s about tuning and making choices about how you organize your data. Vitess- a  new project released by YouTube, written in Go, it’s a frontend to MySQL. It does a lot of optimization on the fly, it rewrites queries and acts as a proxy. Currently it serves every YouTube database request. It’s RPC based. Zookeeper - a distributed lock server. It’s used for configuration. Really interesting piece of technology. Hard to use correctly so read the manual Wiseguy - a CGI servlet container. Spitfire - a templating system. It has an abstract syntax tree that let’s them do transformations to make things go faster. Serialization formats - no matter which one you use, they are all expensive. Measure. Don’t use pickle. Not a good choice. Found protocol buffers slow. They wrote their own BSON implementation, which is 10-15 time faster than the one you can download. ...Contiues. Read the blog Watch the video

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• How do I cleanly design a central render/animation loop?

  - by mtoast

  I'm learning some graphics programming, and am in the midst of my first such project of any substance. But, I am really struggling at the moment with how to architect it cleanly. Let me explain. To display complicated graphics in my current language of choice (JavaScript -- have you heard of it?), you have to draw graphical content onto a <canvas> element. And to do animation, you must clear the <canvas> after every frame (unless you want previous graphics to remain). Thus, most canvas-related JavaScript demos I've seen have a function like this: function render() { clearCanvas(); // draw stuff here requestAnimationFrame(render); } render, as you may surmise, encapsulates the drawing of a single frame. What a single frame contains at a specific point in time, well... that is determined by the program state. So, in order for my program to do its thing, I just need to look at the state, and decide what to render. Right? Right. But that is more complicated than it seems. My program is called "Critter Clicker". In my program, you see several cute critters bouncing around the screen. Clicking on one of them agitates it, making it bounce around even more. There is also a start screen, which says "Click to start!" prior to the critters being displayed. Here are a few of the objects I'm working with in my program: StartScreenView // represents the start screen CritterTubView // represents the area in which the critters live CritterList // a collection of all the critters Critter // a single critter model CritterView // view of a single critter Nothing too egregious with this, I think. Yet, when I set out to flesh out my render function, I get stuck, because everything I write seems utterly ugly and reminiscent of a certain popular Italian dish. Here are a couple of approaches I've attempted, with my internal thought process included, and unrelated bits excluded for clarity. Approach 1: "It's conditions all the way down" // "I'll just write the program as I think it, one frame at a time." if (assetsLoaded) { if (userClickedToStart) { if (critterTubDisplayed) { if (crittersDisplayed) { forEach(crittersList, function(c) { if (c.wasClickedRecently) { c.getAgitated(); } }); } else { displayCritters(); } } else { displayCritterTub(); } } else { displayStartScreen(); } } That's a very much simplified example. Yet even with only a fraction of all the rendering conditions visible, render is already starting to get out of hand. So, I dispense with that and try another idea: Approach 2: Under the Rug // "Each view object shall be responsible for its own rendering. // "I'll pass each object the program state, and each can render itself." startScreen.render(state); critterTub.render(state); critterList.render(state); In this setup, I've essentially just pushed those crazy nested conditions to a deeper level in the code, hiding them from view. In other words, startScreen.render would check state to see if it needed actually to be drawn or not, and take the correct action. But this seems more like it only solves a code-aesthetic problem. The third and final approach I'm considering that I'll share is the idea that I could invent my own "wheel" to take care of this. I'm envisioning a function that takes a data structure that defines what should happen at any given point in the render call -- revealing the conditions and dependencies as a kind of tree. Approach 3: Mad Scientist renderTree({ phases: ['startScreen', 'critterTub', 'endCredits'], dependencies: { startScreen: ['assetsLoaded'], critterTub: ['startScreenClicked'], critterList ['critterTubDisplayed'] // etc. }, exclusions: { startScreen: ['startScreenClicked'], // etc. } }); That seems kind of cool. I'm not exactly sure how it would actually work, but I can see it being a rather nifty way to express things, especially if I flex some of JavaScript's events. In any case, I'm a little bit stumped because I don't see an obvious way to do this. If you couldn't tell, I'm coming to this from the web development world, and finding that doing animation is a bit more exotic than arranging an MVC application for handling simple requests - responses. What is the clean, established solution to this common-I-would-think problem?

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• Mixing Forms and Token Authentication in a single ASP.NET Application (the Details)

  - by Your DisplayName here!

  The scenario described in my last post works because of the design around HTTP modules in ASP.NET. Authentication related modules (like Forms authentication and WIF WS-Fed/Sessions) typically subscribe to three events in the pipeline – AuthenticateRequest/PostAuthenticateRequest for pre-processing and EndRequest for post-processing (like making redirects to a login page). In the pre-processing stage it is the modules’ job to determine the identity of the client based on incoming HTTP details (like a header, cookie, form post) and set HttpContext.User and Thread.CurrentPrincipal. The actual page (in the ExecuteHandler event) “sees” the identity that the last module has set. So in our case there are three modules in effect: FormsAuthenticationModule (AuthenticateRequest, EndRequest) WSFederationAuthenticationModule (AuthenticateRequest, PostAuthenticateRequest, EndRequest) SessionAuthenticationModule (AuthenticateRequest, PostAuthenticateRequest) So let’s have a look at the different scenario we have when mixing Forms auth and WS-Federation. Anoymous request to unprotected resource This is the easiest case. Since there is no WIF session cookie or a FormsAuth cookie, these modules do nothing. The WSFed module creates an anonymous ClaimsPrincipal and calls the registered ClaimsAuthenticationManager (if any) to transform it. The result (by default an anonymous ClaimsPrincipal) gets set. Anonymous request to FormsAuth protected resource This is the scenario where an anonymous user tries to access a FormsAuth protected resource for the first time. The principal is anonymous and before the page gets rendered, the Authorize attribute kicks in. The attribute determines that the user needs authentication and therefor sets a 401 status code and ends the request. Now execution jumps to the EndRequest event, where the FormsAuth module takes over. The module then converts the 401 to a redirect (302) to the forms login page. If authentication is successful, the login page sets the FormsAuth cookie.   FormsAuth authenticated request to a FormsAuth protected resource Now a FormsAuth cookie is present, which gets validated by the FormsAuth module. This cookie gets turned into a GenericPrincipal/FormsIdentity combination. The WS-Fed module turns the principal into a ClaimsPrincipal and calls the registered ClaimsAuthenticationManager. The outcome of that gets set on the context. Anonymous request to STS protected resource This time the anonymous user tries to access an STS protected resource (a controller decorated with the RequireTokenAuthentication attribute). The attribute determines that the user needs STS authentication by checking the authentication type on the current principal. If this is not Federation, the redirect to the STS will be made. After successful authentication at the STS, the STS posts the token back to the application (using WS-Federation syntax). Postback from STS authentication After the postback, the WS-Fed module finds the token response and validates the contained token. If successful, the token gets transformed by the ClaimsAuthenticationManager, and the outcome is a) stored in a session cookie, and b) set on the context. STS authenticated request to an STS protected resource This time the WIF Session authentication module kicks in because it can find the previously issued session cookie. The module re-hydrates the ClaimsPrincipal from the cookie and sets it.     FormsAuth and STS authenticated request to a protected resource This is kind of an odd case – e.g. the user first authenticated using Forms and after that using the STS. This time the FormsAuth module does its work, and then afterwards the session module stomps over the context with the session principal. In other words, the STS identity wins.   What about roles? A common way to set roles in ASP.NET is to use the role manager feature. There is a corresponding HTTP module for that (RoleManagerModule) that handles PostAuthenticateRequest. Does this collide with the above combinations? No it doesn’t! When the WS-Fed module turns existing principals into a ClaimsPrincipal (like it did with the FormsIdentity), it also checks for RolePrincipal (which is the principal type created by role manager), and turns the roles in role claims. Nice! But as you can see in the last scenario above, this might result in unnecessary work, so I would rather recommend consolidating all role work (and other claims transformations) into the ClaimsAuthenticationManager. In there you can check for the authentication type of the incoming principal and act accordingly. HTH

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• Why do we use Pythagoras in game physics?

  - by Starkers

  I've recently learned that we use Pythagoras a lot in our physics calculations and I'm afraid I don't really get the point. Here's an example from a book to make sure an object doesn't travel faster than a MAXIMUM_VELOCITY constant in the horizontal plane: MAXIMUM_VELOCITY = <any number>; SQUARED_MAXIMUM_VELOCITY = MAXIMUM_VELOCITY * MAXIMUM_VELOCITY; function animate(){ var squared_horizontal_velocity = (x_velocity * x_velocity) + (z_velocity * z_velocity); if( squared_horizontal_velocity <= SQUARED_MAXIMUM_VELOCITY ){ scalar = squared_horizontal_velocity / SQUARED_MAXIMUM_VELOCITY; x_velocity = x_velocity / scalar; z_velocity = x_velocity / scalar; } } Let's try this with some numbers: An object is attempting to move 5 units in x and 5 units in z. It should only be able to move 5 units horizontally in total! MAXIMUM_VELOCITY = 5; SQUARED_MAXIMUM_VELOCITY = 5 * 5; SQUARED_MAXIMUM_VELOCITY = 25; function animate(){ var x_velocity = 5; var z_velocity = 5; var squared_horizontal_velocity = (x_velocity * x_velocity) + (z_velocity * z_velocity); var squared_horizontal_velocity = 5 * 5 + 5 * 5; var squared_horizontal_velocity = 25 + 25; var squared_horizontal_velocity = 50; // if( squared_horizontal_velocity <= SQUARED_MAXIMUM_VELOCITY ){ if( 50 <= 25 ){ scalar = squared_horizontal_velocity / SQUARED_MAXIMUM_VELOCITY; scalar = 50 / 25; scalar = 2.0; x_velocity = x_velocity / scalar; x_velocity = 5 / 2.0; x_velocity = 2.5; z_velocity = z_velocity / scalar; z_velocity = 5 / 2.0; z_velocity = 2.5; // new_horizontal_velocity = x_velocity + z_velocity // new_horizontal_velocity = 2.5 + 2.5 // new_horizontal_velocity = 5 } } Now this works well, but we can do the same thing without Pythagoras: MAXIMUM_VELOCITY = 5; function animate(){ var x_velocity = 5; var z_velocity = 5; var horizontal_velocity = x_velocity + z_velocity; var horizontal_velocity = 5 + 5; var horizontal_velocity = 10; // if( horizontal_velocity >= MAXIMUM_VELOCITY ){ if( 10 >= 5 ){ scalar = horizontal_velocity / MAXIMUM_VELOCITY; scalar = 10 / 5; scalar = 2.0; x_velocity = x_velocity / scalar; x_velocity = 5 / 2.0; x_velocity = 2.5; z_velocity = z_velocity / scalar; z_velocity = 5 / 2.0; z_velocity = 2.5; // new_horizontal_velocity = x_velocity + z_velocity // new_horizontal_velocity = 2.5 + 2.5 // new_horizontal_velocity = 5 } } Benefits of doing it without Pythagoras: Less lines Within those lines, it's easier to read what's going on ...and it takes less time to compute, as there are less multiplications Seems to me like computers and humans get a better deal without Pythagoras! However, I'm sure I'm wrong as I've seen Pythagoras' theorem in a number of reputable places, so I'd like someone to explain me the benefit of using Pythagoras to a maths newbie. Does this have anything to do with unit vectors? To me a unit vector is when we normalize a vector and turn it into a fraction. We do this by dividing the vector by a larger constant. I'm not sure what constant it is. The total size of the graph? Anyway, because it's a fraction, I take it, a unit vector is basically a graph that can fit inside a 3D grid with the x-axis running from -1 to 1, z-axis running from -1 to 1, and the y-axis running from -1 to 1. That's literally everything I know about unit vectors... not much :P And I fail to see their usefulness. Also, we're not really creating a unit vector in the above examples. Should I be determining the scalar like this: // a mathematical work-around of my own invention. There may be a cleverer way to do this! I've also made up my own terms such as 'divisive_scalar' so don't bother googling var divisive_scalar = (squared_horizontal_velocity / SQUARED_MAXIMUM_VELOCITY); var divisive_scalar = ( 50 / 25 ); var divisive_scalar = 2; var multiplicative_scalar = (divisive_scalar / (2*divisive_scalar)); var multiplicative_scalar = (2 / (2*2)); var multiplicative_scalar = (2 / 4); var multiplicative_scalar = 0.5; x_velocity = x_velocity * multiplicative_scalar x_velocity = 5 * 0.5 x_velocity = 2.5 Again, I can't see why this is better, but it's more "unit-vector-y" because the multiplicative_scalar is a unit_vector? As you can see, I use words such as "unit-vector-y" so I'm really not a maths whiz! Also aware that unit vectors might have nothing to do with Pythagoras so ignore all of this if I'm barking up the wrong tree. I'm a very visual person (3D modeller and concept artist by trade!) and I find diagrams and graphs really, really helpful so as many as humanely possible please!

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• Profiling Startup Of VS2012 &ndash; YourKit Profiler

  - by Alois Kraus

  The YourKit (v7.0.5) profiler is interesting in terms of price (79€ single place license, 409€ + 1 year support and upgrades) and feature set. You do get a performance and memory profiler in one package for which you normally need also to pay extra from the other vendors. As an interesting side note the profiler UI is written in Java because they do also sell Java profilers with the same feature set. To get all methods of a VS startup you need first to configure it to include System* in the profiled methods and you need to configure * to measure wall clock time. By default it does record only CPU times which allows you to optimize CPU hungry operations. But you will never see a Thread.Sleep(10000) in the profiler blocking the UI in this mode. It can profile as all others processes started from within the profiler but it can also profile the next or all started processes. As usual it can profile in sampling and tracing mode. But since it is a memory profiler as well it does by default also record all object allocations > 1MB. With allocation recording enabled VS2012 did crash but without allocation recording there were no problems. The CPU tab contains the time line of the application and when you click in the graph you the call stacks of all threads at this time. This is really a nice feature. When you select a time region you the CPU Usage estimation for this time window. I have seen many applications consuming 100% CPU only because they did create garbage like crazy. For this is the Garbage Collection tab interesting in conjunction with a time range. This view is like the CPU table only that the CPU graph (green) is missing. All relevant information except for GCs/s is already visible in the CPU tab. Very handy to pinpoint excessive GC or CPU bound issues. The Threads tab does show the thread names and their lifetime. This is useful to see thread interactions or which thread is hottest in terms of CPU consumption. On the CPU tab the call tree does exist in a merged and thread specific view. When you click on a method you get below a list of all called methods. There you can sort for methods with a high own time which are worth optimizing. In the Method List you can select which scope you want to see. Back Traces are the methods which did call you. Callees ist the list of methods called directly or indirectly by your method as a flat list. This is not a call stack but still very useful to see which methods were slow so you can see the “root” cause quite quickly without the need to click trough long call stacks. The last view Merged Calles is a call stacked view of the previous view. This does help a lot to understand did call each method at run time. You would get the same view with a debugger for one call invocation but here you get the full statistics (invocation count) as well. Since YourKit is also a memory profiler you can directly see which objects you have on your managed heap and which objects do hold most of your precious memory. You can in in the Object Explorer view also examine the contents of your objects (strings or whatsoever) to get a better understanding which objects where potentially allocating this stuff.   YourKit is a very easy to use combined memory and performance profiler in one product. The unbeatable single license price makes it very attractive to straightly buy it. Although it is a Java UI it is very responsive and the memory consumption is considerably lower compared to dotTrace and ANTS profiler. What I do really like is to start the YourKit ui and then start the processes I want to profile as usual. There is no need to alter your own application code to be able to inject a profiler into your new started processes. For performance and memory profiling you can simply select the process you want to investigate from the list of started processes. That's the way I like to use profilers. Just get out of the way and let the application run without any special preparations.   Next: Telerik JustTrace

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• How to design a high-level application protocol for metadata syncing between devices and server?

  - by Jaanus

  I am looking for guidance on how to best think about designing a high-level application protocol to sync metadata between end-user devices and a server. My goal: the user can interact with the application data on any device, or on the web. The purpose of this protocol is to communicate changes made on one endpoint to other endpoints through the server, and ensure all devices maintain a consistent picture of the application data. If user makes changes on one device or on the web, the protocol will push data to the central repository, from where other devices can pull it. Some other design thoughts: I call it "metadata syncing" because the payloads will be quite small, in the form of object IDs and small metadata about those ID-s. When client endpoints retrieve new metadata over this protocol, they will fetch actual object data from an external source based on this metadata. Fetching the "real" object data is out of scope, I'm only talking about metadata syncing here. Using HTTP for transport and JSON for payload container. The question is basically about how to best design the JSON payload schema. I want this to be easy to implement and maintain on the web and across desktop and mobile devices. The best approach feels to be simple timer- or event-based HTTP request/response without any persistent channels. Also, you should not have a PhD to read it, and I want my spec to fit on 2 pages, not 200. Authentication and security are out of scope for this question: assume that the requests are secure and authenticated. The goal is eventual consistency of data on devices, it is not entirely realtime. For example, user can make changes on one device while being offline. When going online again, user would perform "sync" operation to push local changes and retrieve remote changes. Having said that, the protocol should support both of these modes of operation: Starting from scratch on a device, should be able to pull the whole metadata picture "sync as you go". When looking at the data on two devices side by side and making changes, should be easy to push those changes as short individual messages which the other device can receive near-realtime (subject to when it decides to contact server for sync). As a concrete example, you can think of Dropbox (it is not what I'm working on, but it helps to understand the model): on a range of devices, the user can manage a files and folders—move them around, create new ones, remove old ones etc. And in my context the "metadata" would be the file and folder structure, but not the actual file contents. And metadata fields would be something like file/folder name and time of modification (all devices should see the same time of modification). Another example is IMAP. I have not read the protocol, but my goals (minus actual message bodies) are the same. Feels like there are two grand approaches how this is done: transactional messages. Each change in the system is expressed as delta and endpoints communicate with those deltas. Example: DVCS changesets. REST: communicating the object graph as a whole or in part, without worrying so much about the individual atomic changes. What I would like in the answers: Is there anything important I left out above? Constraints, goals? What is some good background reading on this? (I realize this is what many computer science courses talk about at great length and detail... I am hoping to short-circuit it by looking at some crash course or nuggets.) What are some good examples of such protocols that I could model after, or even use out of box? (I mention Dropbox and IMAP above... I should probably read the IMAP RFC.)

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