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  • The value of money

    - by ambreesh
    A dictionary definition of money is "any circulating medium of exchange, including coins, paper money, anddemand deposits". If you ask an economist for a definition of money, you will be introduced to terms like M1, M2, M3, all of which denote tangible assets - currency, and anything that is liquid enough to be used as currency; checks, stamps and now mobile minutes being examples. The macroeconomic theory of money is fascinating - the effect of money supply on exchange rates and interest rates, the concept of the "money multiplier" (if I deposit $10 into a bank, the bank will likely loan $8 of it to someone else, who will then give it to someone else in exchange for goods and services, who will then likely deposit it again, which will result in the bank loaning it again and so on - making that $10 of money supply worth a lot more ($10+$8+$x+...)).  But all this depends on money supply - in other words, money that is printed by the mint. The Treasury Department spends a lot of time figuring out how much money to print, there is lot being written on QE2 now-a-days, which is intended to increase the money supply. Money is used to purchase goods and services, and yes it is saved too but that is so one can purchase goods and services later. Completely unrelated, there is a sea change occurring in the web world, dominated by, I believe, Facebook. With 500M active users and growing, FB has the ability to introduce a "money supply" which is completely unrelated to today's "money". Using today's money, a FB user can buy a certain number of FB$s, and then use the FB$s within FB to purchase goods and services - with the money multiplier kicking in. I remember talking with a colleague about this a few years ago, the true way to monetize the web is to introduce an alternative system to the existing, and FB has the ability to do just that. There is enough momentum, enough mass for FB to start to monetize its user base. And completely screw up the economists at the Treasury, not to mention disintermediating the banks completely. The only other ubiquitous asset is mobile minutes. People exchanging mobile minutes for tangible goods and services happens today, the big difference however is the demographic. While Safaricom offers this ability in Kenya today, FB has the 15-40 year middle class user as their user. And the next generation is growing up with FB as a standard channel for communicating with their peers. Virtual flowers when going in for the kill? If your target is an avid FB user, why not? It certainly is a lot more green - no pun intended!

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  • What are the arguments against parsing the Cthulhu way?

    - by smarmy53
    I have been assigned the task of implementing a Domain Specific Language for a tool that may become quite important for the company. The language is simple but not trivial, it already allows nested loops, string concatenation, etc. and it is practically sure that other constructs will be added as the project advances. I know by experience that writing a lexer/parser by hand -unless the grammar is trivial- is a time consuming and error prone process. So I was left with two options: a parser generator à la yacc or a combinator library like Parsec. The former was good as well but I picked the latter for various reasons, and implemented the solution in a functional language. The result is pretty spectacular to my eyes, the code is very concise, elegant and readable/fluent. I concede it may look a bit weird if you never programmed in anything other than java/c#, but then this would be true of anything not written in java/c#. At some point however, I've been literally attacked by a co-worker. After a quick glance at my screen he declared that the code is uncomprehensible and that I should not reinvent parsing but just use a stack and String.Split like everybody does. He made a lot of noise, and I could not convince him, partially because I've been taken by surprise and had no clear explanation, partially because his opinion was immutable (no pun intended). I even offered to explain him the language, but to no avail. I'm positive the discussion is going to re-surface in front of management, so I'm preparing some solid arguments. These are the first few reasons that come to my mind to avoid a String.Split-based solution: you need lot of ifs to handle special cases and things quickly spiral out of control lots of hardcoded array indexes makes maintenance painful extremely difficult to handle things like a function call as a method argument (ex. add( (add a, b), c) very difficult to provide meaningful error messages in case of syntax errors (very likely to happen) I'm all for simplicity, clarity and avoiding unnecessary smart-cryptic stuff, but I also believe it's a mistake to dumb down every part of the codebase so that even a burger flipper can understand it. It's the same argument I hear for not using interfaces, not adopting separation of concerns, copying-pasting code around, etc. A minimum of technical competence and willingness to learn is required to work on a software project after all. (I won't use this argument as it will probably sound offensive, and starting a war is not going to help anybody) What are your favorite arguments against parsing the Cthulhu way?* *of course if you can convince me he's right I'll be perfectly happy as well

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  • Oracle CRM For Public Sector, Commercial Business, Education

    - by michael.seback
    Chongqing Transport Commission Improves Management of Transport Projects The Chongqing Transport Commission is responsible for public passenger, road, and waterway transport in urban and rural areas of Chongqing. The commission administers the region's road and water industry; oversees the construction of transport infrastructure; and manages civil aviation, railroads, roads, waterways, ports, and wharves. "After studying the IT initiatives of other provincial transport commissions, we decided to use Siebel Public Sector to build our integrated transport service system. The Siebel software offers powerful functions that allow us to integrate information and improve the management of our road, rail, and waterway infrastructure projects." - Chen Xiaoming, Vice Director, Information Center, Chongqing Transport Commission. Read more here. Siemens Information Services Increases Productivity by 20% Siemens Information Services Pvt, Ltd. provides back-office account processing services to Siemens' vendors. The company works with Siemens' healthcare, energy, and industry divisions in Europe, the United States, and parts of the Asia-Pacific region. It approves financial services such as processing payroll, accounts data, purchase orders, invoices, and payments, and also creates service catalogs for customers and internal teams. "Oracle CRM ON Demand provides us with a complete view of each customer's data from the moment they log a request to the time we close it. This has eliminated manual requests, and improved the service we offer to our clients across the Asia-Pacific region." -Sunil Zutshi, General Manager, IT, Siemens Information Services Pvt, Ltd. Read more here. China Distance Education Holdings Improves Call Center Productivity by 24% China Distance Education Holdings Limited is a leading provider of online education. The organization offers 174 courses through 16 Web sites, including accounting, healthcare, law, and engineering. In 2010, 215,000 students were enrolled. "Online education is a fast growing sector in China. To maintain our competitiveness, we implemented Oracle Contact Center Anywhere to make it easier and faster for our call center staff to respond to student enquiries. As a result, their productivity increased by 24%." - Qin Songjiang, Chief Technology Officer, China Distance Education Holdings Limited. Read more here.

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  • Is this Ubuntu One DBus signal connection code correct?

    - by Chris Wilson
    This is my first time using DBus so I'm not entirely sure if I'm going about this the right way. I'm attempting to connect the the Ubuntu One DBus service and obtain login credentials for my app, however the slots I've connected to the DBus return signals detailed here never seem to be firing, despite a positive result being returned during the connection. Before I start looking for errors in the details relating to this specific service, could someone please tell me if this code would even work in the first place, or if I'm done something wrong here? int main() { UbuntuOneDBus *u1Dbus = new UbuntuOneDBus; if( u1Dbus->init() ){ qDebug() << "Message queued"; } } UbuntuOneDBus::UbuntuOneDBus() { service = "com.ubuntuone.Credentials"; path = "/credentials"; interface = "com.ubuntuone.CredentialsManagement"; method = "register"; signature = "a{ss} (Dict of {String, String})"; connectReturnSignals(); } bool UbuntuOneDBus::init() { QDBusMessage message = QDBusMessage::createMethodCall( service, path, interface, method ); bool queued = QDBusConnection::sessionBus().send( message ); return queued; } void UbuntuOneDBus::connectReturnSignals() { bool connectionSuccessful = false; connectionSuccessful = QDBusConnection::sessionBus().connect( service, path, interface, "CredentialsFound", "a{ss} (Dict of {String, String})", this, SLOT( credentialsFound() ) ); if( ! connectionSuccessful ) qDebug() << "Connection to DBus::CredentialsFound signal failed"; connectionSuccessful = QDBusConnection::systemBus().connect( service, path, interface, "CredentialsNotFound", "(nothing)", this, SLOT( credentialsNotFound() ) ); if( ! connectionSuccessful ) qDebug() << "Connection to DBus::CredentialsNotFound signal failed"; connectionSuccessful = QDBusConnection::systemBus().connect( service, path, interface, "CredentialsError", "a{ss} (Dict of {String, String})", this, SLOT( credential if( ! connectionSuccessful ) qDebug() << "Connection to DBus::CredentialsError signal failed"; } void UbuntuOneDBus::credentialsFound() { std::cout << "Credentials found" << std::endl; } void UbuntuOneDBus::credentialsNotFound() { std::cout << "Credentials not found" << std::endl; } void UbuntuOneDBus::credentialsError() { std::cout << "Credentials error" << std::endl; }

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  • GUI device for throwing a ball

    - by Fredrik Johansson
    The hero has a ball, which shall be thrown with accuracy in a court on iPhone/iPad. The player is seen from above, in a 2D view. In game play, the player reach is between 1/15 and 1/6 of the height of the iPhone screen. The player will run, and try to outmaneuver his opponent, and then throw the ball at a specific location, which is guarded by the opponent (which is also shown on the screen). The player is controlled by a joystick, and that works ok, but how shall I control the stick? Maybe someone can propose a third control method? I've tried the following two approaches: Joystick: Hero has a reach of 1 meter, and this reach is marked with a semi-opaque circle around the player. The ball can be moved by a joystick. When the joystick is moved south, the ball is moved south within the reach circle. There is a direct coupling with the joystick and the position of the ball. I.e. when the joystick is moved max south, the ball is max south within the player reach. At each touch update the speed is calculated, and the Box2d ball position and ball speed are updated. NB, the ball will never be moved outside the reach as long as the player push the joystick. The ball is thrown by swiping the joystick to make the ball move, and then releasing the joystick. At release, the ball will get a smoothed speed of the joystick. Joystick Problem: The throwing accuracy gets bad, because the joystick can not be that big, and a small movement results in quite a large movement of the ball. If the user does not release before the end of the joystick maximum end point, the ball will stop, and when the user releases the joystick the speed of the ball will be zero. Bad... Touch pad A force is applied to the ball by a sweep on a touchpad. The ball is released when the sweep is ended, or when the ball is moved outside the player reach. As there is no one to one mapping between the swipe and the ball position, the precision can be improved. A large swipe can result in a small ball movement. Touch Pad Problem A touchpad is less intuitive. Users do not seem to know what to do with the touch pad. Some tap the touchpad, and then the ball just falls to the ground. As there is no one-to-one mapping, the ball can be moved outside the reach, and then it will just fall to the ground. It's a bit hard to control the ball, especially if the player also moves.

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  • Music Notation Editor - Refactoring view creation logic elseware

    - by Cyril Silverman
    Let me preface by saying that knowing some elementary music theory and music notation may be helpful in grasping the problem at hand. I'm currently building a Music Notation and Tablature Editor (in Javascript). But I've come to a point where the core parts of the program are more or less there. All functionality I plan to add at this point will really build off the foundation that I've created. As a result, I want to refactor to really solidify my code. I'm using an API called VexFlow to render notation. Basically I pass the parts of the editor's state to VexFlow to build the graphical representation of the score. Here is a rough and stripped down UML diagram showing you the outline of my program: In essence, a Part has many Measures which has many Notes which has many NoteItems (yes, this is semantically weird, as a chord is represented as a Note with multiple NoteItems, individual pitches or fret positions). All of the relationships are bi-directional. There are a few problems with my design because my Measure class contains the majority of the entire application view logic. The class holds the data about all VexFlow objects (the graphical representation of the score). It contains the graphical Staff object and the graphical notes. (Shouldn't these be placed somewhere else in the program?) While VexFlowFactory deals with actual creation (and some processing) of most of the VexFlow objects, Measure still "directs" the creation of all the objects and what order they are supposed to be created in for both the VexFlowStaff and VexFlowNotes. I'm not looking for a specific answer as you'd need a much deeper understanding of my code. Just a general direction to go in. Here's a thought I had, create an MeasureView/NoteView/PartView classes that contains the basic VexFlow objects for each class in addition to any extraneous logic for it's creation? but where would these views be contained? Do I create a ScoreView that is a parallel graphical representation of everything? So that ScoreView.render() would cascade down PartView and call render for each PartView and casade down into each MeasureView, etc. Again, I just have no idea what direction to go in. The more I think about it, the more ways to go seem to pop into my head. I tried to be as concise and simplistic as possible while still getting my problem across. Please feel free to ask me any questions if anything is unclear. It's quite a struggle trying to dumb down a complicated problem to its core parts.

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  • Ubuntu Sluggish and Graphics Problem after Nvidia Driver Update

    - by iam
    I just recently started using Ubuntu (12.04) since a few weeks ago and noticed that the interface is very slow and sluggish: On Dash, I have to type the entire app name and wait a few seconds before it shows up in the search box, and a bit later before it displays search result Opening new files or applications takes also quite long and awkward Dragging icons or moving app windows around is not very spontaneous too: I have to take extra attention in moving the mouse otherwise Ubuntu would not do a correct movement or might ends up doing something incorrect instead e.g. opening the windows to full screen options or move the file to different folders, which is frustrating My PC is a few years old already (1.7 GB RAM) so this could be a reason too but when I checked in System Monitor it's hardly ever consuming much memory. Plus web-surfing on Firefox is actually lightning fast (much more than Windows), so I suspect there might be something wrong with the graphics driver (mine is GeForce 7050). I checked around System Settings and found an option to update the Nvidia driver. So I tried it and restarted, as instructed. Now, I got into a big problem upon restart... as the login-screen windows (where I have to type in the password) would take several attempts to display and finally did not manage to (it'd freeze for several seconds before there's any movement again). The background screen also kept reloading several times too and at some point the screen turned black with pixelated color strips running on the bottom 1/3 of the screen, and after a long while the background screen would come up again. Eventually I'd manage to be able to access the desktop but the launcher, top menu bar and app windows border would not disappear. I searched around and found many other people have this similar problem after updating Nvidia driver too, and on some threads the suggestion is to use "killall -u $USER" in command line (it's the only thing among various online suggestions I could do, as at that point I could not access Terminal without the launcher - Ctrl-Alt-T doesn't work for me). So I did that and was able to access the desktop correctly again with launchee/menu by creating a new account. But I would still have the same problem if logging into my original account. So I just finally tried upgrading to 12.10 and now can access my original account with fully-functional desktop - the launcher, menu and windows border are all back now. However, the problem with sluggishness still remains. And now I get scared of ever having to update the Nvidia driver again! I wonder if anyone knows what's the reason that updating the Nvidia driver is causing this problem and is there a way I can update it safely in the future? I'm still not sure how to solve the problem with the sluggishness too and not sure where else to look to find a solution.

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  • Canonicalization issue regarding academic URL vs. blog URL

    - by user5395
    I'm sorry if what I am about to write is long-winded. I only wish to be clear. I am an academic in the scientific community. I maintain a web site for my research, teaching, and other professional activities. Until recently, the content for this site was hosted in a directory on my university department's own server. The address is of the typical form (universityname).edu/~(myusername) I decided that I wanted to use WordPress in order to host and manage my page. So I set up a WordPress.com blog and then replaced the index.html file in (universityname).edu/~(myusername) with a new one consisting of a single frame, containing the WordPress.com blog. Now when a user visits (universityname).edu/~(myusername), he or she sees the blog instead. This has been pretty nice because, even when the user clicks on links between pages or posts in the blog, the only thing showing up in the address bar of the browser is www.(universityname).edu/~(myusername), because the blog is constrained to a frame. However, the effect of this change on the search side of things has not been so kind to me. Before, when someone searched for my name in Google, the first result was always (universityname).edu/~(myusername). This is the most desirable outcome, for professional reasons. (Having my academic URL come up first suggests that I am an accredited professional, and not just some crank with a blog!) But now, Google seems to have canonicalized my web presence under the blog's WordPress.com address. It has completely forgotten about my academic URL and considers the WordPress.com address to be the best address representing me on the web. Unfortunately, WordPress.com doesn't support the canonical tag, so I can't tell the blog to advertise itself as my academic URL in the header. (It doesn't seem to help at all that I have used the WordPress.com dashboard to turn on no-indexing of the blog.) One obvious solution would be to use the departmental server to host my content again, and use a local installation of the WordPress platform. For reasons beyond my control, the platform will not be deployed on the departmental server at this time. Another solution would be to use shared hosting with WordPress.org support, because the WordPress.org platform does support the canonical tag (albeit via a plug-in). But this seems to usually require purchasing a domain name and other fees, and there is no guarantee that Google will listen to the canonical tag (it might use whatever domain name I end up with instead). Is there a way I can more cleverly integrate the WordPress.com blog into a page hosted on my department's server? Is there some PHP code I can write to retrieve the blog's contents in a way that Google won't treat as a link / "perceive" the blog? Please note: I am a PHP novice at best. I just feel there should be a simpler solution to all this, within the constraints of what I have described above. Thanks!

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  • Broken package after update: linux-headers, error brokencount >0

    - by escozul
    Ubuntu 12.04. After an update, I get a red warning icon in the system tray, warning about an error: broken count 0 Opening Update manager, I see that the broken package is linux-headers-3.2.0-33-generic-pae (new install) Specificaly I have my ubuntu on an AspireOne with 8gb internal storage. I tried apt-get clean as suggested in another question on this site, and tried reinstalling the package in Synaptic. I have tried to reboot but to no avail. I have also tried apt-get install --fix-broken and I get the following: sudo apt-get install --fix-broken [sudo] password for elina: Reading package lists... Done Building dependency tree Reading state information... Done Correcting dependencies... Done The following extra packages will be installed: linux-headers-3.2.0-33-generic-pae The following NEW packages will be installed: linux-headers-3.2.0-33-generic-pae 0 upgraded, 1 newly installed, 0 to remove and 38 not upgraded. 1 not fully installed or removed. Need to get 0 B/977 kB of archives. After this operation 11,3 MB of additional disk space will be used. Do you want to continue [Y/n]; y (Reading database ... 437051 files and directories currently installed.) Unpacking linux-headers-3.2.0-33-generic-pae (from .../linux-headers-3.2.0-33-generic-pae_3.2.0-33.52_i386.deb) ... dpkg: error processing /var/cache/apt/archives/linux-headers-3.2.0-33-generic-pae_3.2.0-33.52_i386.deb (--unpack): unable to create `/usr/src/linux-headers-3.2.0-33-generic-pae/include/config/usb/gspca/sonixb.h.dpkg-new' (while processing `./usr/src/linux-headers-3.2.0-33-generic-pae/include/config/usb/gspca/sonixb.h'): No space left on device No apport report written because the error message indicates a disk full error dpkg-deb: error: subprocess paste was killed by signal (Broken pipe) Errors were encountered while processing: /var/cache/apt/archives/linux-headers-3.2.0-33-generic-pae_3.2.0-33.52_i386.deb E: Sub-process /usr/bin/dpkg returned an error code (1) I've tried all suggestions I could find: sudo apt-get clean sudo apt-get autoclean sudo apt-get autoremove sudo apt-get update sudo apt-get upgrade sudo apt-get -f install sudo apt-get install --fix-broken Then I saw that on the error there was a mention about free space. So I did a df -h and the result was: Filesystem Size Used Avail Use% Mounted on /dev/sda1 7,0G 5,5G 1,1G 84% / udev 235M 4,0K 235M 1% /dev tmpfs 97M 816K 96M 1% /run none 5,0M 0 5,0M 0% /run/lock none 242M 352K 242M 1% /run/shm I see that on my root folder I have 1.1Gb free. The broken package is linux-headers-3.2.0-33-generic-pae_3.2.0-33.52_i386.deb which only takes up 11.3Mb on my hard drive. I'm soooo lost. I really hope there is something I'm missing here. I don't want to go about reformatting this bucket. It's really not worth the time. Any help for fixing this would be hot.

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  • Configure Calendar Server 7 to Use the davUniqueId Attribute

    - by dabrain
    Starting with Calendar Server 7 Update 3 (Patch 08) we introduce a new attribute davUniqueId in the davEntity objectclass, to use as the unique identifier.  The reason behind this is quite simple, the LDAP operational attribute nsUniqueId  has been chosen as the default value used for the unique identifier. It was discovered that this choice has a potential serious downside. The problem with using nsUniqueId is that if the LDAP entry for a user, group, or resource is deleted and recreated in LDAP, the new entry would receive a different nsUniqueId value from the Directory Server, causing a disconnect from the existing account in the calendar database. As a result, recreated users cannot access their existing calendars. How To Configure Calendar Server to Use the davUniqueId Attribute? Populate the davUniqueId to the ldap users. You can create a LDIF output file only or (-x option) directly run the ldapmodify from the populate-davuniqueid shell script. # ./populate-davuniqueid -h localhost -p 389 -D "cn=Directory Manager" -w <passwd> -b "o=red" -O -o /tmp/out.ldif The ldapmodify might failed like below, in that case the LDAP entry already have the 'daventity' objectclass, in those cases run populate-davuniqueid script without the -O option. # ldapmodify -x -h localhost -p 389 -D "cn=Directory Manager" -w <passwd> -c -f /tmp/out.ldif modifying entry "uid=mparis,ou=People,o=vmdomain.tld,o=red" ldapmodify: Type or value exists (20) In this case the user 'mparis' already have the objectclass 'daventity', ldapmodify do not take care of this DN and just take the next DN (if you start ldapmodify with -c option otherwise it stop's completely) dn: uid=mparis,ou=People,o=vmdomain.tld,o=red changetype: modify add: objectclass objectclass: daventity - add: davuniqueid davuniqueid: 01a2c501-af0411e1-809de373-18ff5c8d Even run populate-davuniqueid without -O option or changing the outputfile to dn: uid=mparis,ou=People,o=vmdomain.tld,o=red changetype: modify add: davuniqueid davuniqueid: 01a2c501-af0411e1-809de373-18ff5c8d The ldapmodify works fine now. The only issue I see here is you need verify which user might need the 'daventity' objectclass as well. On the other hand start without the objectclass and only add the objectclass for the users where you get 'Objectclass violation' report. That's indicate the objectclass is missing. # ldapmodify -x -h localhost -p 389 -D "cn=Directory Manager" -w <passwd> -c -f /tmp/out.ldif modifying entry "uid=mparis,ou=People,o=vmdomain.tld,o=red" Now it is time to change the configuration to use the davuniquid attribute # ./davadmin config modify -o davcore.uriinfo.permanentuniqueid -v davuniqueid It is also needed to modfiy the search filter to use davuniqueid instead of nsuniqueid # ./davadmin config modify -o davcore.uriinfo.subjectattributes -v "cn davstore icsstatus mail mailalternateaddress davUniqueId  owner preferredlanguageuid objectclass ismemberof uniquemember memberurl mgrprfc822mailmember" Afterward IWC Calendar works fine and my test user able to access all his old events.

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  • What are some good realistic programming related movies (docu-dramas, documentaries, accurate fiction, etc)?

    - by EpsilonVector
    A while ago I asked this question and the result was this. Following the response I got in the meta question I'm re-asking the question with new guidelines to focus it on the direction I wanted it to have originally. ================================================================== The guidelines are as follows: by "programming related" I mean movies from which we can learn about stuff like the development process, or history of software/computers, or programming culture. In other words, they must be grounded in the industry. No tangential stuff. Good entries answer as many of the following criteria as possible: Teach you about the history of the industry, or the development process, or teach you about important industry related topics (software patents for example) Are based on real life events, companies, people, practices, and they are the main focus of the movie After watching them, you feel like you understand or know something about the programmers' world that you didn't before (or you can see how someone could have such a response). You can point to it and say "this faithfully represents the industry/programmer culture at some point in time". This might be something you would show laymen to explain to them what "your people" are like and what is it that you do. Examples for good entries include: Pirates of Silicon Valley- the story of how Microsoft and Apple started the industry. Revolution OS- The story of Linux's rise to fame, and a pretty good cover of the Free Software/Open Source world. Aardvark'd: 12 Weeks with Geeks- development process. Examples for bad entries: Movies who's sole relevance is that they can be appreciated by programmers. The point of this question is not to be "what are some good movies" with "for a programmer" appended to it. Just because the writers got a few computer jokes right in itself doesn't make it about the industry. Movies where there's a computer related element, but are not about the industry. For example, 24 (the TV series). It's a product of the information age but it isn't actually about it. Another example is movies where there's a really cool programmer character, but are overall about something completely different. Likewise, The Big Bang Theory is not about physics, even though they have a cool physicist as a character. Science fiction, even if it draws ideas from computers. For example, the Matrix trilogy. Movies that you can't point to them and say: this is a faithful representation of our world (at some point in time). If you can't do that then it doesn't mirror the industry. Keep it one entry per answer so that the voting could sort the entries out.

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  • F# Objects &ndash; Integrating with the other .Net Languages &ndash; Part 1

    - by MarkPearl
    In the next few blog posts I am going to explore objects in F#. Up to now, my dabbling in F# has really been a few liners and while I haven’t reached the point where F# is my language of preference – I am already seeing the benefits of the language when solving certain types of programming problems. For me I believe that the F# language will be used in a silo like architecture and that the real benefit of having F# under your belt is so that you can solve problems that F# lends itself towards and then interact with other .Net languages in doing the rest. When I was still very new to the F# language I did the following post covering how to get F# & C# to talk to each other. Today I am going to use a similar approach to demonstrate the structure of F# objects when inter-operating with other languages. Lets start with an empty F# class … type Person() = class end   Very simple, and all we really have done is declared an object that has nothing in it. We could if we wanted to make an object that takes a constructor with parameters… the code for this would look something like this… type Person =     {         Firstname : string         Lastname : string     }   What’s interesting about this syntax is when you try and interop with this object from another .Net language like C# - you would see the following…   Not only has a constructor been created that accepts two parameters, but Firstname and Lastname are also exposed on the object. Now it’s important to keep in mind that value holders in F# are immutable by default, so you would not be able to change the value of Firstname after the construction of the object – in C# terms it has been set to readonly. One could however explicitly state that the value holders were mutable, which would then allow you to change the values after the actual creation of the object. type Person = { mutable Firstname : string mutable Lastname : string }   Something that bugged me for a while was what if I wanted to have an F# object that requires values in its constructor, but does not expose them as part of the object. After bashing my head for a few moments I came up with the following syntax – which achieves this result. type Person(Firstname : string, Lastname : string) = member v.Fullname = Firstname + " " + Lastname What I haven’t figured out yet is what is the difference between the () & {} brackets when declaring an object.

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  • Visual WebGui's XAML based programming for web developers

    - by Webgui
    While ASP.NET provides an event base approach it is completely dismissed when working with AJAX and the richness of the server is lost and replaced with JavaScript programming and couple with a very high security risk. Visual WebGui reinstates the power of the server to AJAX development and provides a statefull yet scalable, server centric architecture that provides the benefits and user productivity of AJAX with the security and developer productivity we had before AJAX stormed into our lives. "When I first came up with the concept of Visual WebGui , I was frustrated by the fragile and complex nature of developing web applications. The contrast in productivity between working in a fully OOP compiled environment vs. scripting even today, with JQuery, Dojo and such, is still huge. Even today the greatest sponsor of JavaScript programming, Google, is offering a framework to avoid JavaScript using Java that compiles to JavaScript (GWT). So I decided to find a way to abstract the complexity or rather delegate the complex job to enable developers to concentrate on the “What” instead of the “How” and embraced the Form based approach," said Guy Peled the inventor of Visual WebGui. Although traditional OOP development still rules the enterprise, the differences between web sites and web applications have blurred and so did the differences between classic developers and web developers. As a result, we now see declarative languages in desktop / backend development environments (WPF / WF) and we see OOP, gaining more and more power in web development (ASP.NET MVC / ASP.NET DOM). However, what has not changed is enterprise need for security, development ROI, reach, highly responsive and interactive UIs and scalability. The advantages that declarative languages and 'on demand' compilation provide over classic development are mostly the flexibility and a more readable initialize component it offers which is what Gizmox is aspiring to do by replacing the designer initialize component with XAML code. The code in this new project template will be compiled on demand using the build provider mechanism ASP.NET has. This means that the performance hit is only on the first request and after that the performance is the same as a prebuilt solution. This will allow the flexibility of a dynamically updated sites and the power of fully blown enterprise applications over web. You can also use prebuilt features available in ASP.NET to enjoy both worlds in production. VWG XAML implementation (VWG Sites) will be the first truly compliable XAML implementation as Microsoft implemented Silverlight and WPF as a runtime markup interpretation opposed to the ASP.NET markup implementation which is compiled to CLR code once. We have chosen to implement the VWG Sites parser as a different way to create CLR code that provides greater performance over the reflection alternative. VWG Sites will also be the first server side XAML UI engine which, while giving the power of XAML, it will not require any plug-ins or installations on the client side. Short demo video of VWG Sites markup. There is also a live sample available here.

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  • CAM v2.0 ships – all new foundation version

    - by drrwebber
    The latest release of the CAM editor toolset is now available on Sourceforge.net – search NIEM. In this all new version the support from Oracle has enabled a transformation of the editor underpinning Java framework and results in 3x performance improvement and 50% better memory utilization. The result of nearly six months of improvements are catalogued in the release notes. http://sourceforge.net/projects/camprocessor/files/CAM%20Editor/Releases/2.0/CAM_Editor_2-0_Release_Notes.pdf/download However here I’d like to talk about the strategic vision and highlight specific new go to features that make a difference for exchange schema designers and with a focus on the NIEM community. So why is this a foundation version? Basically the new drag and drop designer tool allows you to tailor your own dictionary collection of components and then simply select and position those into your resulting exchange structure. This is true global reuse enabled from a canonical domain dictionary collection. So instead of grappling with XSD Schema syntax, or UML model nuances – this is straightforward direct WYSIWYG visual engineering – using familiar sets of business components. Then the toolkit writes the complex XSD Schema for you, along with test samples, documentation, XMI/UML models, Mindmaps and more. So how do you get a set of business components? The toolkit allows you to harvest these from existing schema collections or enterprise data models, or as in the case of NIEM, existing domain dictionary collections. I’ve been using this for the latest IEEE/OASIS/NIST initiative on a Common Data Format (CDF) for elections management systems. So you can download those from OASIS and see how this can transform how you build actual business exchanges – improving the quality, consistency and usability – and dramatically allowing automated generation of artifacts you only dreamed of before – such as a model of your entire major exchange collection components. http://www.oasis-open.org/committees/documents.php?wg_abbrev=election So what we have here is a foundation version – setting the scene and the basis for changing how people can generate and manage information exchanges. A foundation built using the OASIS CAM standard combined with aspects of the NIEM Naming and Design Rules and the UN/CEFACT Core Components specifications and emerging work on OASIS CIQ name and address and ANSI/ISO code list schema. We still have a raft of work to do to integrate this into SOA best practices and extend the dictionary capabilities to assist true community development. Answering questions such as: - How good is my canonical component collection? - How much reuse is really occurring? - What inconsistencies and extensions are there in the dictionary components? Expect us to begin tackling these areas now that the foundation is in place. The immediate need is to develop training and self-start materials – so we will be focusing there for the next couple of months and especially leading up to the IJIS industry event in July in New Jersey, and the NIEM NTE event in August in Philadelphia. http://sourceforge.net/projects/camprocessor

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  • Stencil buffer appears to not be decrementing values correctly

    - by Alex Ames
    I'm attempting to use the stencil buffer as a clipper for my UI system, but I'm having trouble debugging a problem I'm running in to. This is what I'm doing: A widget can pass a rectangle to the the stencil clipper functions, which will increment the stencil buffer values that it covers. Then it will draw its children, which will only get drawn in the stencilled area (so that if they extend outside they'll be clipped). After a widget is done drawing its children, it pops that rectangle from the stack and in the process decrements the values in the stencil buffer that it has previously incremented. The slightly simplified code is below: static void drawStencil(Rect& rect, unsigned int ref) { // Save previous values of the color and depth masks GLboolean colorMask[4]; GLboolean depthMask; glGetBooleanv(GL_COLOR_WRITEMASK, colorMask); glGetBooleanv(GL_DEPTH_WRITEMASK, &depthMask); // Turn off drawing glColorMask(0, 0, 0, 0); glDepthMask(0); // Draw vertices here ... // Turn everything back on glColorMask(colorMask[0], colorMask[1], colorMask[2], colorMask[3]); glDepthMask(depthMask); // Only render pixels in areas where the stencil buffer value == ref glStencilFunc(GL_EQUAL, ref, 0xFF); glStencilOp(GL_KEEP, GL_KEEP, GL_KEEP); } void pushScissor(Rect rect) { // increment things only at the current stencil stack level glStencilFunc(GL_EQUAL, s_scissorStack.size(), 0xFF); glStencilOp(GL_KEEP, GL_INCR, GL_INCR); s_scissorStack.push_back(rect); drawStencil(rect, states, s_ScissorStack.size()); } void popScissor() { // undo what was done in the previous push, // decrement things only at the current stencil stack level glStencilFunc(GL_EQUAL, s_scissorStack.size(), 0xFF); glStencilOp(GL_KEEP, GL_DECR, GL_DECR); Rect rect = s_scissorStack.back(); s_scissorStack.pop_back(); drawStencil(rect, states, s_scissorStack.size()); } And this is how it's being used by the Widgets if (m_clip) pushScissor(m_rect); drawInternal(target, states); for (auto child : m_children) target.draw(*child, states); if (m_clip) popScissor(); This is the result of the above code: There are two things on the screen, a giant test button, and a window with some buttons and text areas on it. The text area scroll box is set to clip its children (so that the text doesn't extend outside the scroll box). The button is drawn after the window and should be on top of it completely. However, for some reason the text area is appearing on top of the button. The only reason I can think of that this would happen is if the stencil values were not getting decremented in the pop, and when it comes time to render the button, since those pixels don't have the right stencil value it doesn't draw over. But I can't figure out whats wrong with my code that would cause that to happen.

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  • Why is it necessary to install EFI/rEFInd/UEFI/... on a SD Card since the Macbook Pro seems to already have it?

    - by user170794
    Dear askubuntu members, I own a Macbook Pro (late 2009) and when I boot the laptop and hold the alt key meanwhile, there is a EFI screen, so EFI is installed on... the firmware? I had a few troubles with my hard disk, so I had to change it, but I haven't installed OS X, I have only installed Ubuntu and still the EFI screen is there which is surely a good thing. As the new hard disk is making troubles again, I am using Puppy Linux, booting from a CD each time, which is unconfortable. So I am trying to have Ubuntu installed on a SD Card. After having spent many months on the internet grabing informations anywhere I can and trying several things, I applied this method: http://www.weihermueller.de/mac/ I succeeded in making one SD Card recognizable by the EFI of my laptop (holding alt key @ boot), but nothing installed on it yet as I fear to lose the recognizable-by-EFI part. I haven't succeded in producing the same result on another SD Card. I have a bootable USB key of Ubuntu (yipee) which works like a live CD, made with the help of Universal Linux UDF Creator, found there: http://www.pendrivelinux.com/universal-usb-installer-easy-as-1-2-3/ on which I have put Ubuntu 13.04 64bit, retrieved from the official deposits. Eventhough I have to add the "nouveau.noaccel=1" option to the grub command line launching Linux, it works (yipee again) properly as a live cd. When installing Ubuntu I come across the "where do I wanna put Ubuntu" window, I partition another SD Card in: the EFI part (40MB) the Linux part (15GB< <16GB) The installation works fine and finishes with no problem. But at the reboot, the SD Card where Linux is installed is not recognized by the EFI, the icons are : the CD (Puppy Linux), the USB stick (from Linux UDF Creator), the hard drive (the formerly-working Ubuntu 12) but no fourth icon of the SD Card whatsoever. As the title of this thread suggests, I am wondering: why there is a need for EFI to be installed on the SD Card since EFI seems to be on my laptop anyway? why EFI has to be on a different partition than the Linux's one? How do both parts communicate? why the EFI part on the SD Card made with the help of the live-USB key isn't recognized? on the EFI partition, there is a folder named "EFI" which contains another folder named "ubuntu" which contains a file named "grubx64.efi", why is there a thing called grub? Is it the Linux's grub where one can chose either to boot, to boot in safe mode, etc.? Thank you for your patience, looking forward for any kind of answer, Julien

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  • Unexpected results for projection on to plane

    - by ravenspoint
    I want to use this projection matrix: GLfloat shadow[] = { -1,0,0,0, 1,0,-1,1, 0,0,-1,0, 0,0,0,-1 }; It should cast object shadows onto the y = 0 plane from a point light at 1,1,-1. I create a rectangle in the x = 0.5 plane glBegin( GL_QUADS ); glVertex3f( 0.5,0.2,-0.5); glVertex3f( 0.5,0.2,-1.5); glVertex3f( 0.5,0.5,-1.5); glVertex3f( 0.5,0.5,-0.5); glEnd(); Now if I manually multiply these vertices with the matrix, I get. glBegin( GL_QUADS ); glVertex3f( 0.375,0,-0.375); glVertex3f( 0.375,0,-1.625); glVertex3f( 0,0,-2); glVertex3f( 0,0,0); glEnd(); Which produces a reasonable display ( camera at 0,5,0 looking down y axis ) So rather than do the calculation manually, I should be able to use the opengl model transormation. I write this code: glMatrixMode (GL_MODELVIEW); GLfloat shadow[] = { -1,0,0,0, 1,0,-1,1, 0,0,-1,0, 0,0,0,-1 }; glLoadMatrixf( shadow ); glBegin( GL_QUADS ); glVertex3f( 0.5,0.2,-0.5); glVertex3f( 0.5,0.2,-1.5); glVertex3f( 0.5,0.5,-1.5); glVertex3f( 0.5,0.5,-0.5); glEnd(); But this produces a blank screen! What am I doing wrong? Is there some debug mode where I can print out the transformed vertices, so I can see where they are ending up? Note: People have suggested that using glMultMatrixf() might make a difference. It doesn't. Replacing glLoadMatrixf( shadow ); with glLoadIdentity(); glMultMatrixf( shadow ); gives the identical result ( of course! )

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  • links for 2010-12-22

    - by Bob Rhubart
    @hajonormann: BPM: Top Seven Architectural Topics in 2010 Oracle ACE Director Hajo Normann offers details on how to design a BPM/SOA solution including: modeling human interaction, improving BPM models, orchestrating composed services, central task management, new approaches for business-IT alignment, solutions for non-deterministic processes, and choreography. (tags: oracle otn soasymposium infoq soa bpm) InfoQ: Simplicity, The Way of the Unusual Architect Dan North talks about the tendency developers-becoming-architects have to create bigger and more complex systems. Without trying to be simplistic, North argues for simplicity, offering strategies to extract the simple essence from complex situations. (tags: ping.fm) Fun with Sun Ray, 3D, Oracle VM x86 and SRIOV (Wim Coekaerts Blog) "One of the things I like about my job is that I get to play around with stuff and make use of the technologies we work on in my teams. Sort of my own little playground." - Wim Coekaerts (tags: oracle otn virtualization oraclevm) Oracle VM VirtualBox 4.0.0 Released! (Oracle's Virtualization Blog) And you were worried about what to get that special someone for Christmas... (tags: oracle otn virtualization virtualbox) Virtual Developer Day: Oracle WebLogic Server & Java EE (#OTNVDD) (Oracle Technology Network Blog (aka TechBlog)) "Virtual Developer Day is back with a vengeance! On Feb. 1, login to learn how Oracle WebLogic Server enables a whole new level of productivity for enterprise developers." Registration is open. (tags: oracle otn events webinar java) New Coherence 3.6 Oracle University Course (Cristóbal Soto's Blog) Cristóbal Soto shares information on the "Oracle Coherence 3.6: Share and Manage Data in Clusters" course now available through Oracle University. (tags: oracle otn grid coherence) The Aquarium: Oracle WebLogic Server & Java EE developer day "Oracle WebLogic is well on its way to contribute to the general Java EE 6 momentum and the OTN Blog has just announced a Virtual Developer Day for Oracle WebLogic." (tags: oracle otn weblogic java) Enterprise 2.0 Use Cases for Semantic Web (Reiser 2.0) "How can an enterprise improve the efficiency and effectiveness of their Knowledge and Community model leveraging semantic technologies and social networking dynamics?" - Peter Reiser (tags: oracle otn enterprise2.0 semanticweb) John Gøtze: European Interoperability Framework 2.0 "This week, the European Commission announced an updated interoperability policy in the EU. The Commission has committed itself to adopt a Communication that introduces the European Interoperability Strategy (EIS) and an update to the European Interoperability Framework (EIF)..." - John Gøtze (tags: entarch Interoperability) Andy Mulholland: Maybe Web 3.0 is quite understandable – and a natural result "The idea of Web 1.0 = content, Web 2.0 = people and Web 3.0 = services has a nice symmetrical feel to it, in fact it feels basically right as such a definition would include the two other major definitions as well. So if we put these things all together what picture do we see?" - Andy Mulholland (tags: web2.0 web3.0) Ken Downs: A Working Definition of Business Logic, with Implications for CRUD Code "The Wikipedia entry on 'Business Logic' has a wonderfully honest opening sentence stating that 'Business logic, or domain logic, is a non-technical term...'"  (tags: businesslogic crud)

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  • Database Security: The First Step in Pre-Emptive Data Leak Prevention

    - by roxana.bradescu
    With WikiLeaks raising awareness around information leaks and the harm they can cause, many organization are taking stock of their own information leak protection (ILP) strategies in 2011. A report by IDC on data leak prevention stated: Increasing database security is one of the most efficient and cost-effective measures an organization can take to prevent data leaks. By utilizing the data protection, access control, account management, encryption, log management, and other security controls inherent in the database management system, entities can institute first-level control over the widest range of protected information. As a central repository for unstructured data, which is growing at leaps and bounds, the database should be the first layer providing information leakage protection. Unfortunately, most organizations are not taking sufficient steps to protect their databases according to a survey of the Independent Oracle User Group. For example, any operating system administrator or database administrator can access the all the data stored in the database in most organizations. Without any kind of auditing or monitoring. And it's not just administrators, database users can typically access the database with ad-hoc query tools from their desktop and by-pass any application level controls. Despite numerous regulations calling for controls to limit the powers of insiders, most organizations still put too many privileges in the hands of their employees. Time and time again these excess privileges have backfired. Internal agents were implicated in almost half of data breaches according to the Verizon Data Breach Investigations Report and the rate is rising. Hackers also took advantage of these excess privileges very successfully using stolen credentials and SQL injection attacks. But back to the insiders. Who are these insiders and why do they do it? In 2002, the U.S. Secret Service (USSS) behavioral psychologists and CERT information security experts formed the Insider Threat Study team to examine insider threat cases that occurred in US critical infrastructure sectors, and examined them from both a technical and a behavioral perspective. A series of fascinating reports has been published as a result of this work. You can learn more by watching the ISSA Insider Threat Web Conference. So as your organization starts to look at data leak prevention over the coming year, start off by protecting your data at the source - your databases. IDC went on to say: Any enterprise looking to improve its competitiveness, regulatory compliance, and overall data security should consider Oracle's offerings, not only because of their database management capabilities but also because they provide tools that are the first layer of information leak prevention. Learn more about Oracle Database Security solutions and get the whitepapers, demos, tutorials, and more that you need to protect data privacy from internal and external threats.

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  • Highlights From Interact '12 - Healthcare Industry User Group

    - by John Webb
    Last week the Oracle team traveled to Orlando for the 18th annual Healthcare Industry User Group (HIUG) conference, Interact '12.   HIUG has over 3,000 members representing 180 organizations.  While we now know the result on the SCOTUS ruling yesterday, the consensus at the conference last week was summed up well in the welcome note from HIUG President, Chris Ryzewski:    "Regardless of the legal ruling on this administration's  Patient Protection and Affordable Care Act we will undoubtedly be called upon to further reduce costs and be more efficient in every aspect of our business processes."    Well put!   Attendance exceeded previous years with several hundred attendees, over 100 sessions, and a trade show that numbered 40 booths.    Most of the HIUG members use PeopleSoft applications and they tend to be full suite customers who use PeopleSoft broadly from HCM to Financials and Supply Chain. For many customers who have licensed PeopleSoft in the last year, it was their first experience with a very strong and collaborative user group.   I had dinner with a provider who is rolling out PeopleSoft HCM and ERP to a nationwide system of forty hospitals.  A key driver for this organization and others is how to leverage PeopleSoft applications to meet the cost reduction goals mentioned above.   In the area of procurement, the topic of Supplier Contract Management attracted a lot of attention.  Contract pricing and adherence to contracts throughout the procure to pay life cycle are key to meeting cost containment objectives.  Customers were excited to see the new faceted search capabilities and usability of  the upcoming PeopleSoft eProcurement release.     The new Work Center concept was discussed in several areas including the Cost Reconciliation Work Center and the Supply Demand Work Center which enables healthcare specific functions around PAR counts and related replenishment activities.  The latest Feature Pack of HCM 9.1 was demonstrated with the Talent Summary and Manager Dashboard.   Customers were excited to see the major advances in self service available today.    The Grants Special Interest Group focused quite a bit on the usage of PeopleSoft's Project Costing "Funds Distribution" feature, which can be used to manage capital projects funded by multiple agencies and sources.  Along with the latest release of the Mobile Inventory solution that several hospitals have now implemented, a preview of new mobile applications for expenses and approvals drew a lot of attention.   The PeopleSoft focus on assisting these companies in their goals to contain costs and create new efficiencies continues forward.   We look foward to Interact '13!     

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  • How migrate my keyring (containing ssh passprases, nautilus remote filesystem, pgp passwords) and network manager connections?

    - by con-f-use
    I changed the disk on my laptop and installed Ubuntu on the new disk. Old disk had 12.04 upgraded to 12.10 on it. Now I want to copy my old keyring with WiFi passwords, ftp passwords for nautilus and ssh key passphrases. I have the whole data from the old disk available (is now a USB disk and I did not delete the old data yet or do anything with it - I could still put it in the laptop and boot from it like nothing happened). On the new disc that is now in my laptop, I have installed 12.10 with the same password, user-id and username as on the old disk. Then I copied a few important config files from the old disk (e.g. ~/.firefox/, ~/.mozilla, ~/.skype and so on, which all worked fine... except for the key ring: The old methods of just copying ~/.gconf/... and ~/.gnome2/keyrings won't work. Did I miss something? 1. Edit: I figure one needs to copy files not located in the users home directory as well. I copied the whole old /home/confus (which is my home directory) to the fresh install to no effect. That whole copy is now reverted to the fresh install's home directory, so my /home/confus is as it was the after fresh install. 2. Edit: The folder /etc/NetworkManager/system-connections seems to be the place for WiFi passwords. Could be that /usr/share/keyrings is important as well for ssh keys - that's the only sensible thing that a search came up with: find /usr/ -name "*keyring* 3. Edit: Still no ssh and ftp passwords from the keyring. What I did: Convert old hard drive to usb drive Put new drive in the laptop and installed fresh version of 12.10 there (same uid, username and passwort) Booted from old hdd via USB and copied its /etc/NetwrokManager/system-connections, ~/.gconf/ and ~/.gnome2/keyrings, ~/.ssh over to the new disk. Confirmed that all keys on the old install work Booted from new disk Result: No passphrase for ssh keys, no ftp passwords in keyring. At least the WiFi passwords are migrated. 4. Edit: Boutny! Ending soon... 5. Edit: Keyring's now in ./local/share/keyrings/. Also interesting .gnupg

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  • Simplifying C++11 optimal parameter passing when a copy is needed

    - by Mr.C64
    It seems to me that in C++11 lots of attention was made to simplify returning values from functions and methods, i.e.: with move semantics it's possible to simply return heavy-to-copy but cheap-to-move values (while in C++98/03 the general guideline was to use output parameters via non-const references or pointers), e.g.: // C++11 style vector<string> MakeAVeryBigStringList(); // C++98/03 style void MakeAVeryBigStringList(vector<string>& result); On the other side, it seems to me that more work should be done on input parameter passing, in particular when a copy of an input parameter is needed, e.g. in constructors and setters. My understanding is that the best technique in this case is to use templates and std::forward<>, e.g. (following the pattern of this answer on C++11 optimal parameter passing): class Person { std::string m_name; public: template <class T, class = typename std::enable_if < std::is_constructible<std::string, T>::value >::type> explicit Person(T&& name) : m_name(std::forward<T>(name)) { } ... }; A similar code could be written for setters. Frankly, this code seems boilerplate and complex, and doesn't scale up well when there are more parameters (e.g. if a surname attribute is added to the above class). Would it be possible to add a new feature to C++11 to simplify code like this (just like lambdas simplify C++98/03 code with functors in several cases)? I was thinking of a syntax with some special character, like @ (since introducing a &&& in addition to && would be too much typing :) e.g.: class Person { std::string m_name; public: /* Simplified syntax to produce boilerplate code like this: template <class T, class = typename std::enable_if < std::is_constructible<std::string, T>::value >::type> */ explicit Person(std::string@ name) : m_name(name) // implicit std::forward as well { } ... }; This would be very convenient also for more complex cases involving more parameters, e.g. Person(std::string@ name, std::string@ surname) : m_name(name), m_surname(surname) { } Would it be possible to add a simplified convenient syntax like this in C++? What would be the downsides of such a syntax?

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  • Throwing exception from a property when my object state is invalid

    - by Rumi P.
    Microsoft guidelines say: "Avoid throwing exceptions from property getters", and I normally follow that. But my application uses Linq2SQL, and there is the case where my object can be in invalid state because somebody or something wrote nonsense into the database. Consider this toy example: [Table(Name="Rectangle")] public class Rectangle { [Column(Name="ID", IsPrimaryKey = true, IsDbGenerated = true)] public int ID {get; set;} [Column(Name="firstSide")] public double firstSide {get; set;} [Column(Name="secondSide")] public double secondSide {get; set;} public double sideRatio { get { return firstSide/secondSide; } } } Here, I could write code which ensures that my application never writes a Rectangle with a zero-length side into the database. But no matter how bulletproof I make my own code, somebody could open the database with a different application and create an invalid Rectangle, especially one with a 0 for secondSide. (For this example, please forget that it is possible to design the database in a way such that writing a side length of zero into the rectangle table is impossible; my domain model is very complex and there are constraints on model state which cannot be expressed in a relational database). So, the solution I am gravitating to is to change the getter to: get { if(firstSide > 0 && secondSide > 0) return firstSide/secondSide; else throw new System.InvalidOperationException("All rectangle sides should have a positive length"); } The reasoning behind not throwing exceptions from properties is that programmers should be able to use them without having to make precautions about catching and handling them them. But in this case, I think that it is OK to continue to use this property without such precautions: if the exception is thrown because my application wrote a non-zero rectangle side into the database, then this is a serious bug. It cannot and shouldn't be handled in the application, but there should be code which prevents it. It is good that the exception is visibly thrown, because that way the bug is caught. if the exception is thrown because a different application changed the data in the database, then handling it is outside of the scope of my application. So I can't do anything about it if I catch it. Is this a good enough reasoning to get over the "avoid" part of the guideline and throw the exception? Or should I turn it into a method after all? Note that in the real code, the properties which can have an invalid state feel less like the result of a calculation, so they are "natural" properties, not methods.

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  • Default values - are they good or evil?

    - by Andrew
    The question about default values in general - default return function values, default parameter values, default logic for when something is missing, default logic for handling exceptions, default logic for handling the edge conditions etc. For a long time I considered default values to be a "pure evil" thing, something that "cloaks the catastrophe" and results in a very hard do find bugs. But recently I started to think about default values as some sort of a technical debt ... which is not a straight bad thing but something that could provide some "short term financing" get us to survive the project (how many of us could afford to buy a house without taking out the mortgage?). When I say a "short term" - I don't mean - "do something quickly first and do refactor it out later before it hits the production". No - I am talking about relying on a hardcoded default values in a production software. Granted - it could cause some issues, but what if it only going to cause a single trouble in a whole year. Again - I am talking about the "average" mainstream software here (not a software for a nuclear power station) - the average web site or a UI application for the accounting software, meaning that people lives are not at stake, nor millions of dollars. Again, from my experience, business users would rather live with the software which "works somehow", rather then wait for a perfect one. And the use of default values helps a lot if you develop a software in a RAD style. But again - the longest debug sessions I have spent were because of the bugs introduced by a default value which either stopped being "a default" along the way or because a small subsystem has recently been upgraded and as a result of this upgrade it does not handle the default correctly (e.g. empty list vs null, or null string vs empty string). So my question is - are the default values good or evil. And if they are a technical debt - how do measure up how much you can borrow so you can afford the repayments? Would really appreciate any input. Cheers. EDIT: If I am using the default values as a way to cut the corners during the development - and if the corners cutting results in a bugs and issues - what is the methodology to recover from these issues?

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  • Mixing Forms and Token Authentication in a single ASP.NET Application

    - by Your DisplayName here!
    I recently had the task to find out how to mix ASP.NET Forms Authentication with WIF’s WS-Federation. The FormsAuth app did already exist, and a new sub-directory of this application should use ADFS for authentication. Minimum changes to the existing application code would be a plus ;) Since the application is using ASP.NET MVC this was quite easy to accomplish – WebForms would be a little harder, but still doable. I will discuss the MVC solution here. To solve this problem, I made the following changes to the standard MVC internet application template: Added WIF’s WSFederationAuthenticationModule and SessionAuthenticationModule to the modules section. Add a WIF configuration section to configure the trust with ADFS. Added a new authorization attribute. This attribute will go on controller that demand ADFS (or STS in general) authentication. The attribute logic is quite simple – it checks for authenticated users – and additionally that the authentication type is set to Federation. If that’s the case all is good, if not, the redirect to the STS will be triggered. public class RequireTokenAuthenticationAttribute : AuthorizeAttribute {     protected override bool AuthorizeCore(HttpContextBase httpContext)     {         if (httpContext.User.Identity.IsAuthenticated &&             httpContext.User.Identity.AuthenticationType.Equals( WIF.AuthenticationTypes.Federation, StringComparison.OrdinalIgnoreCase))         {             return true;         }                     return false;     }     protected override void HandleUnauthorizedRequest(AuthorizationContext filterContext)     {                    // do the redirect to the STS         var message = FederatedAuthentication.WSFederationAuthenticationModule.CreateSignInRequest( "passive", filterContext.HttpContext.Request.RawUrl, false);         filterContext.Result = new RedirectResult(message.RequestUrl);     } } That’s it ;) If you want to know why this works (and a possible gotcha) – read my next post.

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