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  • System Variables, Stored Procedures or Functions for Meta Data

    - by BuckWoody
    Whenever you want to know something about SQL Server’s configuration, whether that’s the Instance itself or a database, you have a few options. If you want to know “dynamic” data, such as how much memory or CPU is consumed or what a particular query is doing, you should be using the Dynamic Management Views (DMVs) that you can read about here: http://msdn.microsoft.com/en-us/library/ms188754.aspx  But if you’re looking for how much memory is installed on the server, the version of the Instance, the drive letters of the backups and so on, you have other choices. The first of these are system variables. You access these with a SELECT statement, and they are useful when you need a discrete value for use, say in another query or to put into a table. You can read more about those here: http://msdn.microsoft.com/en-us/library/ms173823.aspx You also have a few stored procedures you can use. These often bring back a lot more data, pre-formatted for the screen. You access these with the EXECUTE syntax. It is a bit more difficult to take the data they return and get a single value or place the results in another table, but it is possible. You can read more about those here: http://msdn.microsoft.com/en-us/library/ms187961.aspx Yet another option is to use a system function, which you access with a SELECT statement, which also brings back a discrete value that you can use in a test or to place in another table. You can read about those here: http://msdn.microsoft.com/en-us/library/ms187812.aspx  By the way, many of these constructs simply query from tables in the master or msdb databases for the Instance or the system tables in a user database. You can get much of the information there as well, and there are even system views in each database to show you the meta-data dealing with structure – more on that here: http://msdn.microsoft.com/en-us/library/ms186778.aspx  Some of these choices are the only way to get at a certain piece of data. But others overlap – you can use one or the other, they both come back with the same data. So, like many Microsoft products, you have multiple ways to do the same thing. And that’s OK – just research what each is used for and how it’s intended to be used, and you’ll be able to select (pun intended) the right choice. Share this post: email it! | bookmark it! | digg it! | reddit! | kick it! | live it!

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  • GlassFish Clustering with DCOM on Windows

    - by ByronNevins
    DCOM - Distributed COM, a Microsoft protocol for communicating with Windows machines. Why use DCOM? In GlassFish 3.1 SSH is used as the standard way to run commands on remote nodes for clustering.  It is very difficult for users to get SSH configured properly on Windows.  SSH does not come with Windows so we have to depend on third party tools.  And then the user is forced to install and configure these tools -- which can be tricky. DCOM is available on all supported platforms.  It is built-in to Windows. The idea is to use DCOM to communicate with remote Windows nodes.  This has the huge advantage that the user has to do minimal, if any, configuration on the Windows nodes. Implementation HighlightsTwo open Source Libraries have been added to GlassFish: Jcifs – a SAMBA implementation in Java J-interop – A Java implementation for making DCOM calls to remote Windows computers.   Note that any supported platform can use DCOM to work with Windows nodes -- not just Windows.E.g. you can have a Linux DAS work with Windows remote instances.All existing SSH commands now have a corresponding DCOM command – except for setup-ssh which isn’t needed for DCOM.  validate-dcom is an all new command. New DCOM Commands create-node-dcom delete-node-dcom install-node-dcom list-nodes-dcom ping-node-dcom uninstall-node-dcom update-node-dcom validate-dcom setup-local-dcom (This is only available via Update Center for GlassFish 3.1.2) These commands are in-place in the trunk (4.0).  And in the branch (3.1.2) Windows Configuration Challenges There are an infinite number of possible configurations of Windows if you look at it as a combination of main release, service-pack, special drivers, software, configuration etc.  Later versions of Windows err on the side of tightening security be default.  This means that the Windows host may need to have configuration changes made.These configuration changes mostly need to be made by the user.  setup-local-dcom will assist you in making required changes to the Windows Registry.  See the reference blogs for details. The validate-dcom Command validate-dcom is a crucial command.  It should be run before any other commands.  If it does not run successfully then there is no point in running other commands.The validate-dcom command must be used from a DAS machine to test a different Windows machine.  If  validate-dcom runs successfully you can be confident that all the DCOM commands will work.  Conversely, the opposite is also true:  If validate-dcom fails, then no DCOM commands will work. What validate-dcom does Verify that the remote host is not the local machine. Resolves the remote host name Checks that the remote DCOM port is being listened on (135, 139) Checks that the remote host’s File Sharing is enabled (port 445) It copies a file (a script) to the remote host to verify that SAMBA is working and authorization is correct It runs a script that it copied on-the-fly to the remote host. Tips and Tricks The bread and butter commands that use DCOM are existing commands like create-instance, start-instance etc.   All of the commands that have dcom in their name are for dealing with the actual nodes. The way the software works is to call asadmin.bat on the remote machine and run a command.  This means that you can track these commands easily on the remote machine with the usual tools.  E.g. using AS_LOGFILE, looking at log files, etc.  It’s easy to attach a debugger to the remote asadmin process, “just in time”, if necessary. How to debug the remote commands:Edit the asadmin.bat file that is in the glassfish/bin folder.  Use glassfish/lib/nadmin.bat in GlassFish 4.0+Add these options to the java call:-Xdebug -Xrunjdwp:transport=dt_socket,server=y,suspend=y,address=1234  Now if you run, say start-instance on DAS, you can attach your debugger, at your leisure, to the remote machines port 1234.  It will be running start-local-instance and patiently waiting for you to attach.

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  • How do I prove or disprove "god" objects are wrong?

    - by honestduane
    Problem Summary: Long story short, I inherited a code base and an development team I am not allowed to replace and the use of God Objects is a big issue. Going forward, I want to have us re-factor things but I am getting push-back from the teams who want to do everything with God Objects "because its easier" and this means I would not be allowed to re-factor. I pushed back citing my years of dev experience, that I'm the new boss who was hired to know these things, etc, and so did the third party offshore companies account sales rep, and this is now at the executive level and my meeting is tomorrow and I want to go in with a lot of technical ammo to advocate best practices because I feel it will be cheaper in the long run (And I personally feel that is what the third party is worried about) for the company. My issue is from a technical level, I know its good long term but I'm having trouble with the ultra short term and 6 months term, and while its something I "know" I cant prove it with references and cited resources outside of one person (Robert C. Martin, aka Uncle Bob), as that is what I am being asked to do as I have been told having data from one person and only one person (Robert C Martin) is not good enough of an argument. Question: What are some resources I can cite directly (Title, year published, page number, quote) by well known experts in the field that explicitly say this use of "God" Objects/Classes/Systems is bad (or good, since we are looking for the most technically valid solution)? Research I have already done: I have a number of books here and I have searched their indexes for the use of the words "god object" and "god class". I found that oddly its almost never used and the copy of the GoF book I have for example, never uses it (At least according to the index in front of me) but I have found it in 2 books per the below, but I want more I can use. I checked the Wikipedia page for "God Object" and its currently a stub with little reference links so although I personally agree with that it says, It doesn't have much I can use in an environment where personal experience is not considered valid. The book cited is also considered too old to be valid by the people I am debating these technical points with as the argument they are making is that "it was once thought to be bad but nobody could prove it, and now modern software says "god" objects are good to use". I personally believe that this statement is incorrect, but I want to prove the truth, whatever it is. In Robert C Martin's "Agile Principles, Patterns, and Practices in C#" (ISBN: 0-13-185725-8, hardcover) where on page 266 it states "Everybody knows that god classes are a bad idea. We don't want to concentrate all the intelligence of a system into a single object or a single function. One of the goals of OOD is the partitioning and distribution of behavior into many classes and many function." -- And then goes on to say sometimes its better to use God Classes anyway sometimes (Citing micro-controllers as an example). In Robert C Martin's "Clean Code: A Handbook of Agile Software Craftsmanship" page 136 (And only this page) talks about the "God class" and calls it out as a prime example of a violation of the "classes should be small" rule he uses to promote the Single Responsibility Principle" starting on on page 138. The problem I have is all my references and citations come from the same person (Robert C. Martin), and am from the same single person/source. I am being told that because he is just one guy, my desire to not use "God Classes" is invalid and not accepted as a standard best practice in the software industry. Is this true? Am I doing things wrong from a technical perspective by trying to keep to the teaching of Uncle Bob? God Objects and Object Oriented Programming and Design: The more I think of this the more I think this is more something you learn when you study OOP and its never explicitly called out; Its implicit to good design is my thinking (Feel free to correct me, please, as I want to learn), The problem is I "know" this, but but not everybody does, so in this case its not considered a valid argument because I am effectively calling it out as universal truth when in fact most people are statistically ignorant of it since statistically most people are not programmers. Conclusion: I am at a loss on what to search for to get the best additional results to cite, since they are making a technical claim and I want to know the truth and be able to prove it with citations like a real engineer/scientist, even if I am biased against god objects due to my personal experience with code that used them. Any assistance or citations would be deeply appreciated.

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  • Best Practices For Database Consolidation On Exadata - New Whitepapers

    - by Javier Puerta
     Best Practices For Database Consolidation On Exadata Database Machine (Nov. 2011) Consolidation can minimize idle resources, maximize efficiency, and lower costs when you host multiple schemas, applications or databases on a target system. Consolidation is a core enabler for deploying Oracle database on public and private clouds.This paper provides the Exadata Database Machine (Exadata) consolidation best practices to setup and manage systems and applications for maximum stability and availability:Download here Oracle Exadata Database Machine Consolidation: Segregating Databases and Roles (Sep. 2011) This paper is focused on the aspects of segregating databases from each other in a platform consolidation environment on an Oracle Exadata Database Machine. Platform consolidation is the consolidation of multiple databases on to a single Oracle Exadata Database Machine. When multiple databases are consolidated on a single Database Machine, it may be necessary to isolate certain database components or functions in order to meet business requirements and provide best practices for a secure consolidation. In this paper we outline the use of Oracle Exadata database-scoped security to securely separate database management and provide a detailed case study that illustrates the best practices. Download here

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  • Wednesday at OpenWorld: Identity Management

    - by Tanu Sood
    Divide and conquer! Yes, divide and conquer today at Oracle OpenWorld with your colleagues to make the most of all things Identity Management since there’s a lot going on. Here’ the line-up for today: Wednesday, October 3, 2012 CON9458: End End-User-Managed Passwords and Increase Security with Oracle Enterprise Single Sign-On Plus 10:15 a.m. – 11:15 a.m., Moscone West 3008 Most customers have a broad variety of applications (internal, external, web, client server, host etc) and single sign-on systems that extend to some, but not all systems. This session will focus on how customers are using enterprise single sign-on can help extend single sign-on to virtually any application, without costly application modification while laying a foundation that will enable integration with a broader identity management platform. CON9494: Sun2Oracle: Identity Management Platform Transformation 11:45 a.m. – 12:45 p.m., Moscone West 3008 Sun customers are actively defining strategies for how they will modernize their identity deployments. Learn how customers like Avea and SuperValu are leveraging their Sun investment, evaluating areas of expansion/improvement and building momentum. CON9631: Entitlement-centric Access to SOA and Cloud Services 11:45 a.m. – 12:45 p.m., Marriott Marquis, Salon 7 How do you enforce that a junior trader can submit 10 trades/day, with a total value of $5M, if market volatility is low? How can hide sensitive patient information from clerical workers but make it visible to specialists as long as consent has been given or there is an emergency? In this session, Uberether and HerbaLife take the stage with Oracle to demonstrate how you can enforce such entitlements on a service not just within your intranet but also right at the perimeter. CON3957 - Delivering Secure Wi-Fi on the Tube as an Olympics Legacy from London 2012 11:45 a.m. – 12:45 p.m., Moscone West 3003 In this session, Virgin Media, the U.K.’s first combined provider of broadband, TV, mobile, and home phone services, shares how it is providing free secure Wi-Fi services to the London Underground, using Oracle Virtual Directory and Oracle Entitlements Server, leveraging back-end legacy systems that were never designed to be externalized. As an Olympics 2012 legacy, the Oracle architecture will form a platform to be consumed by other Virgin Media services such as video on demand. CON9493: Identity Management and the Cloud 1:15 p.m. – 2:15 p.m., Moscone West 3008 Security is the number one barrier to cloud service adoption.  Not so for industry leading companies like SaskTel, ConAgra foods and UPMC. This session will explore how these organizations are using Oracle Identity with cloud services and how some are offering identity management as a cloud service. CON9624: Real-Time External Authorization for Middleware, Applications, and Databases 3:30 p.m. – 4:30 p.m., Moscone West 3008 As organizations seek to grant access to broader and more diverse user populations, the importance of centrally defined and applied authorization policies become critical; both to identify who has access to what and to improve the end user experience.  This session will explore how customers are using attribute and role-based access to achieve these goals. CON9625: Taking Control of WebCenter Security 5:00 p.m. – 6:00 p.m., Moscone West 3008 Many organizations are extending WebCenter in a business to business scenario requiring secure identification and authorization of business partners and their users. Leveraging LADWP’s use case, this session will focus on how customers are leveraging, securing and providing access control to Oracle WebCenter portal and mobile solutions. EVENTS: Identity Management Customer Advisory Board 2:30 p.m. – 3:30 p.m., Four Seasons – Yerba Buena Room This invitation-only event is designed exclusively for Customer Advisory Board (CAB) members to provide product strategy and roadmap updates. Identity Management Meet & Greet Networking Event 3:30 p.m. – 4:30 p.m., Meeting Session 4:30 p.m. – 5:30 p.m., Cocktail Reception Yerba Buena Room, Four Seasons Hotel, 757 Market Street, San Francisco The CAB meeting will be immediately followed by an open Meet & Greet event hosted by Oracle Identity Management executives and product management team. Do take this opportunity to network with your peers and connect with the Identity Management customers. For a complete listing, refer to the Focus on Identity Management document. And as always, you can find us on @oracleidm on twitter and FaceBook. Use #oow and #idm to join in the conversation.

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  • Implementing a "state-machine" logic for methods required by an object in C++

    - by user827992
    What I have: 1 hypothetical object/class + other classes and related methods that gives me functionality. What I want: linking this object to 0 to N methods in realtime on request when an event is triggered Each event is related to a single method or a class, so a single event does not necessarily mean "connect this 1 method only" but can also mean "connect all the methods from that class or a group of methods" Avoiding linked lists because I have to browse the entire list to know what methods are linked, because this does not ensure me that the linked methods are kept in a particular order (let's say an alphabetic order by their names or classes), and also because this involve a massive amount of pointers usage. Example: I have an object Employee Jon, Jon acquires knowledge and forgets things pretty easily, so his skills may vary during a period of time, I'm responsible for what Jon can add or remove from his CV, how can I implement this logic?

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  • SQL SERVER – What is Incremental Statistics? – Performance improvements in SQL Server 2014 – Part 1

    - by Pinal Dave
    This is the first part of the series Incremental Statistics. Here is the index of the complete series. What is Incremental Statistics? – Performance improvements in SQL Server 2014 – Part 1 Simple Example of Incremental Statistics – Performance improvements in SQL Server 2014 – Part 2 DMV to Identify Incremental Statistics – Performance improvements in SQL Server 2014 – Part 3 Statistics are considered one of the most important aspects of SQL Server Performance Tuning. You might have often heard the phrase, with related to performance tuning. “Update Statistics before you take any other steps to tune performance”. Honestly, I have said above statement many times and many times, I have personally updated statistics before I start to do any performance tuning exercise. You may agree or disagree to the point, but there is no denial that Statistics play an extremely vital role in the performance tuning. SQL Server 2014 has a new feature called Incremental Statistics. I have been playing with this feature for quite a while and I find that very interesting. After spending some time with this feature, I decided to write about this subject over here. New in SQL Server 2014 – Incremental Statistics Well, it seems like lots of people wants to start using SQL Server 2014′s new feature of Incremetnal Statistics. However, let us understand what actually this feature does and how it can help. I will try to simplify this feature first before I start working on the demo code. Code for all versions of SQL Server Here is the code which you can execute on all versions of SQL Server and it will update the statistics of your table. The keyword which you should pay attention is WITH FULLSCAN. It will scan the entire table and build brand new statistics for you which your SQL Server Performance Tuning engine can use for better estimation of your execution plan. UPDATE STATISTICS TableName(StatisticsName) WITH FULLSCAN Who should learn about this? Why? If you are using partitions in your database, you should consider about implementing this feature. Otherwise, this feature is pretty much not applicable to you. Well, if you are using single partition and your table data is in a single place, you still have to update your statistics the same way you have been doing. If you are using multiple partitions, this may be a very useful feature for you. In most cases, users have multiple partitions because they have lots of data in their table. Each partition will have data which belongs to itself. Now it is very common that each partition are populated separately in SQL Server. Real World Example For example, if your table contains data which is related to sales, you will have plenty of entries in your table. It will be a good idea to divide the partition into multiple filegroups for example, you can divide this table into 3 semesters or 4 quarters or even 12 months. Let us assume that we have divided our table into 12 different partitions. Now for the month of January, our first partition will be populated and for the month of February our second partition will be populated. Now assume, that you have plenty of the data in your first and second partition. Now the month of March has just started and your third partition has started to populate. Due to some reason, if you want to update your statistics, what will you do? In SQL Server 2012 and earlier version You will just use the code of WITH FULLSCAN and update the entire table. That means even though you have only data in third partition you will still update the entire table. This will be VERY resource intensive process as you will be updating the statistics of the partition 1 and 2 where data has not changed at all. In SQL Server 2014 You will just update the partition of Partition 3. There is a special syntax where you can now specify which partition you want to update now. The impact of this is that it is smartly merging the new data with old statistics and update the entire statistics without doing FULLSCAN of your entire table. This has a huge impact on performance. Remember that the new feature in SQL Server 2014 does not change anything besides the capability to update a single partition. However, there is one feature which is indeed attractive. Previously, when table data were changed 20% at that time, statistics update were triggered. However, now the same threshold is applicable to a single partition. That means if your partition faces 20% data, change it will also trigger partition level statistics update which, when merged to your final statistics will give you better performance. In summary If you are not using a partition, this feature is not applicable to you. If you are using a partition, this feature can be very helpful to you. Tomorrow: We will see working code of SQL Server 2014 Incremental Statistics. Reference: Pinal Dave (http://blog.sqlauthority.com)Filed under: PostADay, SQL, SQL Authority, SQL Performance, SQL Query, SQL Server, SQL Tips and Tricks, T SQL Tagged: SQL Statistics, Statistics

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  • Generic and type safe I/O model in any language

    - by Eduardo León
    I am looking for an I/O model, in any programming language, that is generic and type safe. By genericity, I mean there should not be separate functions for performing the same operations on different devices (read_file, read_socket, read_terminal). Instead, a single read operation works on all read-able devices, a single write operation works on all write-able devices, and so on. By type safety, I mean operations that do not make sense should not even be expressible in first place. Using the read operation on a non-read-able device ought to cause a type error at compile time, similarly for using the write operation on a non-write-able device, and so on. Is there any generic and type safe I/O model?

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  • Ways to ensure unique instances of a class?

    - by Peanut
    I'm looking for different ways to ensure that each instance of a given class is a uniquely identifiable instance. For example, I have a Name class with the field name. Once I have a Name object with name initialised to John Smith I don't want to be able to instantiate a different Name object also with the name as John Smith, or if instantiation does take place I want a reference to the orginal object to be passed back rather than a new object. I'm aware that one way of doing this is to have a static factory that holds a Map of all the current Name objects and the factory checks that an object with John Smith as the name doesn't already exist before passing back a reference to a Name object. Another way I could think of off the top of my head is having a static Map in the Name class and when the constructor is called throwing an exception if the value passed in for name is already in use in another object, however I'm aware throwing exceptions in a constructor is generally a bad idea. Are there other ways of achieving this?

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  • A few questions about integrating AudioKinetic Wwise and Unity

    - by SaldaVonSchwartz
    I'm new to Wwise and to using it with Unity, and though I have gotten the integration to work, I'm still dealing with some loose ends and have a few questions: (I'm on Unity 4.3 as of now but I think it shouldn't make any difference) The base path: The Wwise documentation implies you set this in the AkGlobalSoundEngineInitializer basePath public ivar, which is exposed to the editor. However, I found that this variable is not really used. Instead, the path is hardcoded to /Audio/GeneratedSoundBanks in AkBankPath. I had to modify both scripts to actually look in the path that I set in the editor property. What's the deal with this? Just sloppyness or am I missing something? Also about paths: since I'm on Mac, I'm using Unity natively under OS X and in tadem, the Wwise authoring tool via VMWare and I share the OS X Unity project folder so I can generate the soundbanks into the assets folder. However, the authoring tool (downloaded the latest one for Windows) doesn't automatically generate any "platform-specific" subfolders for my wwise files. That is, again, the Unity integration scripts assume the path to be /Audio/GeneratedSoundBanks/<my-platform>/ which in my case would be Mac (I set the authoring tool to generate for Mac). The documentation says wwise will automatically generate the platform-specific folders but it just dumps all the stuff in GeneratedSoundBanks. Am I missing some setting? cause right now I just manually create the /Mac folder. The C# methods AkSoundEngine.PostEvent and AkSoundEngine.LoadBank for instance, have a few overloads, including ones where I can refer to the soundbanks or events by their ID. However, if I try to use these, for instance: AkSoundEngine.LoadBank(, AkSoundEngine.AK_DEFAULT_POOL_ID) where the int I got from the .h header, I get Ak_Fail. If I use the overloads that reference the objects by string name then it works. What gives? Converting the ID header to C#: The integration comes with a C# script that seems to fork a process to call Python in turn to covert the C++ header into a C# script. This always fails unless I manually execute the Python script myself from outside Unity. Might be a permissions thing, but has anyone experienced this? The Profiler: I set up the Unity player to run in the background and am using the "Profile" version of the plugin. However, when I start the Unity OS X standalone app, the profiler in VMWare does not see it. This I'm thinking might just be that I'm trying to see a running instance of the sound engine inside an OS X binary from a Windows virtual machine. But I'm just wondering if anyone has gotten the Windows profiler to see an OS X Unity binary. Different versions of the integration plugin: It's not clear to me from the documentation whether I have to manually (or write a script to do it) remove the "Profile" version and install the "Release" version when I'm going to do a Release build or if I should install both version in Unity and it'll select the right one. Thanks!

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  • Solaris: What comes next?

    - by alanc
    As you probably know by now, a few months ago, we released Solaris 11 after years of development. That of course means we now need to figure out what comes next - if Solaris 11 is “The First Cloud OS”, then what do we need to make future releases of Solaris be, to be modern and competitive when they're released? So we've been having planning and brainstorming meetings, and I've captured some notes here from just one of those we held a couple weeks ago with a number of the Silicon Valley based engineers. Now before someone sees an idea here and calls their product rep wanting to know what's up, please be warned what follows are rough ideas, and as I'll discuss later, none of them have any committment, schedule, working code, or even plan for integration in any possible future product at this time. (Please don't make me force you to read the full Oracle future product disclaimer here, you should know it by heart already from the front of every Oracle product slide deck.) To start with, we did some background research, looking at ideas from other Oracle groups, and competitive OS'es. We examined what was hot in the technology arena and where the interesting startups were heading. We then looked at Solaris to see where we could apply those ideas. Making Network Admins into Socially Networking Admins We all know an admin who has grumbled about being the only one stuck late at work to fix a problem on the server, or having to work the weekend alone to do scheduled maintenance. But admins are humans (at least most are), and crave companionship and community with their fellow humans. And even when they're alone in the server room, they're never far from a network connection, allowing access to the wide world of wonders on the Internet. Our solution here is not building a new social network - there's enough of those already, and Oracle even has its own Oracle Mix social network already. What we proposed is integrating Solaris features to help engage our system admins with these social networks, building community and bringing them recognition in the workplace, using achievement recognition systems as found in many popular gaming platforms. For instance, if you had a Facebook account, and a group of admin friends there, you could register it with our Social Network Utility For Facebook, and then your friends might see: Alan earned the achievement Critically Patched (April 2012) for patching all his servers. Matt is only at 50% - encourage him to complete this achievement today! To avoid any undue risk of advertising who has unpatched servers that are easier targets for hackers to break into, this information would be tightly protected via Facebook's world-renowned privacy settings to avoid it falling into the wrong hands. A related form of gamification we considered was replacing simple certfications with role-playing-game-style Experience Levels. Instead of just knowing an admin passed a test establishing a given level of competency, these would provide recruiters with a more detailed level of how much real-world experience an admin has. Achievements such as the one above would feed into it, but larger numbers of experience points would be gained by tougher or more critical tasks - such as recovering a down system, or migrating a service to a new platform. (As long as it was an Oracle platform of course - migrating to an HP or IBM platform would cause the admin to lose points with us.) Unfortunately, we couldn't figure out a good way to prevent (if you will) “gaming” the system. For instance, a disgruntled admin might decide to start ignoring warnings from FMA that a part is beginning to fail or skip preventative maintenance, in the hopes that they'd cause a catastrophic failure to earn more points for bolstering their resume as they look for a job elsewhere, and not worrying about the effect on your business of a mission critical server going down. More Z's for ZFS Our suggested new feature for ZFS was inspired by the worlds most successful Z-startup of all time: Zynga. Using the Social Network Utility For Facebook described above, we'd tie it in with ZFS monitoring to help you out when you find yourself in a jam needing more disk space than you have, and can't wait a month to get a purchase order through channels to buy more. Instead with the click of a button you could post to your group: Alan can't find any space in his server farm! Can you help? Friends could loan you some space on their connected servers for a few weeks, knowing that you'd return the favor when needed. ZFS would create a new filesystem for your use on their system, and securely share it with your system using Kerberized NFS. If none of your friends have space, then you could buy temporary use space in small increments at affordable rates right there in Facebook, using your Facebook credits, and then file an expense report later, after the urgent need has passed. Universal Single Sign On One thing all the engineers agreed on was that we still had far too many "Single" sign ons to deal with in our daily work. On the web, every web site used to have its own password database, forcing us to hope we could remember what login name was still available on each site when we signed up, and which unique password we came up with to avoid having to disclose our other passwords to a new site. In recent years, the web services world has finally been reducing the number of logins we have to manage, with many services allowing you to login using your identity from Google, Twitter or Facebook. So we proposed following their lead, introducing PAM modules for web services - no more would you have to type in whatever login name IT assigned and try to remember the password you chose the last time password aging forced you to change it - you'd simply choose which web service you wanted to authenticate against, and would login to your Solaris account upon reciept of a cookie from their identity service. Pinning notes to the cloud We also all noted that we all have our own pile of notes we keep in our daily work - in text files in our home directory, in notebooks we carry around, on white boards in offices and common areas, on sticky notes on our monitors, or on scraps of paper pinned to our bulletin boards. The contents of the notes vary, some are things just for us, some are useful for our groups, some we would share with the world. For instance, when our group moved to a new building a couple years ago, we had a white board in the hallway listing all the NIS & DNS servers, subnets, and other network configuration information we needed to set up our Solaris machines after the move. Similarly, as Solaris 11 was finishing and we were all learning the new network configuration commands, we shared notes in wikis and e-mails with our fellow engineers. Users may also remember one of the popular features of Sun's old BigAdmin site was a section for sharing scripts and tips such as these. Meanwhile, the online "pin board" at Pinterest is taking the web by storm. So we thought, why not mash those up to solve this problem? We proposed a new BigAddPin site where users could “pin” notes, command snippets, configuration information, and so on. For instance, once they had worked out the ideal Automated Installation manifest for their app server, they could pin it up to share with the rest of their group, or choose to make it public as an example for the world. Localized data, such as our group's notes on the servers for our subnet, could be shared only to users connecting from that subnet. And notes that they didn't want others to see at all could be marked private, such as the list of phone numbers to call for late night pizza delivery to the machine room, the birthdays and anniversaries they can never remember but would be sleeping on the couch if they forgot, or the list of automatically generated completely random, impossible to remember root passwords to all their servers. For greater integration with Solaris, we'd put support right into the command shells — redirect output to a pinned note, set your path to include pinned notes as scripts you can run, or bring up your recent shell history and pin a set of commands to save for the next time you need to remember how to do that operation. Location service for Solaris servers A longer term plan would involve convincing the hardware design groups to put GPS locators with wireless transmitters in future server designs. This would help both admins and service personnel trying to find servers in todays massive data centers, and could feed into location presence apps to help show potential customers that while they may not see many Solaris machines on the desktop any more, they are all around. For instance, while walking down Wall Street it might show “There are over 2000 Solaris computers in this block.” [Note: this proposal was made before the recent media coverage of a location service aggregrator app with less noble intentions, and in hindsight, we failed to consider what happens when such data similarly falls into the wrong hands. We certainly wouldn't want our app to be misinterpreted as “There are over $20 million dollars of SPARC servers in this building, waiting for you to steal them.” so it's probably best it was rejected.] Harnessing the power of the GPU for Security Most modern OS'es make use of the widespread availability of high powered GPU hardware in today's computers, with desktop environments requiring 3-D graphics acceleration, whether in Ubuntu Unity, GNOME Shell on Fedora, or Aero Glass on Windows, but we haven't yet made Solaris fully take advantage of this, beyond our basic offering of Compiz on the desktop. Meanwhile, more businesses are interested in increasing security by using biometric authentication, but must also comply with laws in many countries preventing discrimination against employees with physical limations such as missing eyes or fingers, not to mention the lost productivity when employees can't login due to tinted contacts throwing off a retina scan or a paper cut changing their fingerprint appearance until it heals. Fortunately, the two groups considering these problems put their heads together and found a common solution, using 3D technology to enable authentication using the one body part all users are guaranteed to have - pam_phrenology.so, a new PAM module that uses an array USB attached web cams (or just one if the user is willing to spin their chair during login) to take pictures of the users head from all angles, create a 3D model and compare it to the one in the authentication database. While Mythbusters has shown how easy it can be to fool common fingerprint scanners, we have not yet seen any evidence that people can impersonate the shape of another user's cranium, no matter how long they spend beating their head against the wall to reshape it. This could possibly be extended to group users, using modern versions of some of the older phrenological studies, such as giving all users with long grey beards access to the System Architect role, or automatically placing users with pointy spikes in their hair into an easy use mode. Unfortunately, there are still some unsolved technical challenges we haven't figured out how to overcome. Currently, a visit to the hair salon causes your existing authentication to expire, and some users have found that shaving their heads is the only way to avoid bad hair days becoming bad login days. Reaction to these ideas After gathering all our notes on these ideas from the engineering brainstorming meeting, we took them in to present to our management. Unfortunately, most of their reaction cannot be printed here, and they chose not to accept any of these ideas as they were, but they did have some feedback for us to consider as they sent us back to the drawing board. They strongly suggested our ideas would be better presented if we weren't trying to decipher ink blotches that had been smeared by the condensation when we put our pint glasses on the napkins we were taking notes on, and to that end let us know they would not be approving any more engineering offsites in Irish themed pubs on the Friday of a Saint Patrick's Day weekend. (Hopefully they mean that situation specifically and aren't going to deny the funding for travel to this year's X.Org Developer's Conference just because it happens to be in Bavaria and ending on the Friday of the weekend Oktoberfest starts.) They recommended our research techniques could be improved over just sitting around reading blogs and checking our Facebook, Twitter, and Pinterest accounts, such as considering input from alternate viewpoints on topics such as gamification. They also mentioned that Oracle hadn't fully adopted some of Sun's common practices and we might have to try harder to get those to be accepted now that we are one unified company. So as I said at the beginning, don't pester your sales rep just yet for any of these, since they didn't get approved, but if you have better ideas, pass them on and maybe they'll get into our next batch of planning.

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  • Coding different states in Adventure Games

    - by Cardin
    I'm planning out an adventure game, and can't figure out what's the right way to implement the behaviour of a level depending on state of story progression. My single-player game features a huge world where the player has to interact with people in a town at various points in the game. However, depending on story progression, different things would be presented to the player, for e.g. the Guild Leader will change locations from the town square to various locations around the city; Doors would only unlock at certain times of the day after finishing a particular routine; Different cut-screen/trigger events happen only after a particular milestone has been reached. I naively thought of using a switch{} statement initially to decide what the NPC should say or which he could be found at, and making quest objectives interact-able only after checking a global game_state variable's condition. But I realised I would quickly run into a lot of different game states and switch-cases in order to change the behaviour of an object. That switch statement would also be massively hard to debug, and I guess it might also be hard to use in a level editor. So I thought, instead of having a single object with multiple states, maybe I should have multiple instances of the same object, with a single state. That way, if I use something like a level editor, I can put an instance of the NPC at all the different locations he could ever appear at, and also an instance for each conversation state he has. But that means there'll be a lot of inactive, invisible game objects floating around the level, which might be trouble for memory, or simply hard to see in a level editor, i don't know. Or simply, make an identical, but separate level for each game state. This feels the cleanest and bug-free way to do things, but it feels like massive manual work making sure each version of the level is really identical to each other. All my methods feel so inefficient, so to recap my question, is there a better or standardised way to implement behaviour of a level depending on state of story progression? PS: I don't have a level editor yet - thinking of using something like JME SDK or making my own.

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  • Dual Monitor results in 'greyed' windows

    - by paula
    This occurs in Maverick and Natty. Single screen is fine, mirror of single screen is fine. If the mirror box is unchecked and the second monitor is turned on to extend the desktop then all windows are greyed out (like they do when a process has timed out and is unresponsive) and pop up menus are greyed out but icons, panels and background are fine and the windows do operate (just can't see them well enough to use) I have a D620 with intel graphics. This machine did work with dual monitors at some time in the past, however I have been using another machine, a D630 with nvidia and it works fine. Yes, there have been any number of updates. I also upgraded from Maverick to Natty to see if it would go away. No joy. Also, the D620 has a dual boot windows system and the windows xp system works fine with daul monitors There is a forum thread that goes into more detail and there are a number of users experiencing this problem. Thread: greyed out windows Thanks for reading paula_ke

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  • Can't specify window's class in CCSM's Place Windows

    - by Anto
    Following this method, I wanted to "place" some of my windows on specific viewports. For instance, I want Xchat to always start on my top right viewport (x=2, y=1). But after I have set everything up and clicked the "Close" button to validate it (I don't have any other action button, like "OK" or "Apply"), the only thing that get saved up are the viewport X and Y coordinates. The window class (in my case class=Xchat) remains empty. This bug only occurs in the "Windows with fixed viewport" section; it works well in the "Windows with fixed placement mode", for instance. How can I solve or circumvent this issue ?

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  • What's wrong with JavaScript

    - by ts01
    There is a lot of buzz around Dart recently, often questioning Google motivations and utility of Dart as replacement for JavaScript. I was searching for rationale of creating Dart rather than investing more effort in ECMAScript. In well known leaked mail its author is saying that Javascript has historical baggage that cannot be solved without a clean break. But there is only one concrete example given (apart of performance concerns) of "fundamental language problems", which is an existence of a single Number primitive So, my questions are: How an existence of a single Number primitive can be a "fundamental problem"? Are there other known "fundamental problems" in JavaScript?

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  • *DX11, HLSL* - Colour as 4 floats or one UINT

    - by Paul
    With the DX11 pipeline, would it be much quicker for the vertex buffer to pass one single UINT with one byte per channel to the input assembler, as opposed to three floats? Then the vertex shader would convert the four bytes to four floats, which I guess is the required colour format for the pipeline. In this instance, colour accuracy isn't an issue. The vertex buffer would need to be updated many times per frame, so using a single UINT and saving 12 bytes for every vertex could well be worth it: quicker uploads to vram and also less memory used. But the cost is the extra shader work for every vertex to convert each 8 bits of the input UNIT into a float. Anyone have an idea if it might be worth doing? Or, is it possible for the pipeline to be set to just internally use a four-byte colour format? The swap chain buffer has been initialised as DXGI_FORMAT_R8G8B8A8_UNORM, so ultimately that's how the colour will be written. Thanks!

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  • ResponseStatusLine protocol violation

    - by Tom Hines
    I parse/scrape a few web page every now and then and recently ran across an error that stated: "The server committed a protocol violation. Section=ResponseStatusLine".   After a few web searches, I found a couple of suggestions – one of which said the problem could be fixed by changing the HttpWebRequest ProtocolVersion to 1.0 with the command: 1: HttpWebRequest req = (HttpWebRequest)HttpWebRequest.Create(strURI); 2: req.ProtocolVersion = HttpVersion.Version10;   …but that did not work in my particular case.   What DID work was the next suggestion I found that suggested the use of the setting: “useUnsafeHeaderParsing” either in the app.config file or programmatically. If added to the app.config, it would be: 1: <!-- after the applicationSettings --> 2: <system.net> 3: <settings> 4: <httpWebRequest useUnsafeHeaderParsing ="true"/> 5: </settings> 6: </system.net>   If done programmatically, it would look like this: C++: 1: // UUHP_CPP.h 2: #pragma once 3: using namespace System; 4: using namespace System::Reflection; 5:   6: namespace UUHP_CPP 7: { 8: public ref class CUUHP_CPP 9: { 10: public: 11: static bool UseUnsafeHeaderParsing(String^% strError) 12: { 13: Assembly^ assembly = Assembly::GetAssembly(System::Net::Configuration::SettingsSection::typeid); //__typeof 14: if (nullptr==assembly) 15: { 16: strError = "Could not access Assembly"; 17: return false; 18: } 19:   20: Type^ type = assembly->GetType("System.Net.Configuration.SettingsSectionInternal"); 21: if (nullptr==type) 22: { 23: strError = "Could not access internal settings"; 24: return false; 25: } 26:   27: Object^ obj = type->InvokeMember("Section", 28: BindingFlags::Static | BindingFlags::GetProperty | BindingFlags::NonPublic, 29: nullptr, nullptr, gcnew array<Object^,1>(0)); 30:   31: if(nullptr == obj) 32: { 33: strError = "Could not invoke Section member"; 34: return false; 35: } 36:   37: FieldInfo^ fi = type->GetField("useUnsafeHeaderParsing", BindingFlags::NonPublic | BindingFlags::Instance); 38: if(nullptr == fi) 39: { 40: strError = "Could not access useUnsafeHeaderParsing field"; 41: return false; 42: } 43:   44: if (!(bool)fi->GetValue(obj)) 45: { 46: fi->SetValue(obj, true); 47: } 48:   49: return true; 50: } 51: }; 52: } C# (CSharp): 1: using System; 2: using System.Reflection; 3:   4: namespace UUHP_CS 5: { 6: public class CUUHP_CS 7: { 8: public static bool UseUnsafeHeaderParsing(ref string strError) 9: { 10: Assembly assembly = Assembly.GetAssembly(typeof(System.Net.Configuration.SettingsSection)); 11: if (null == assembly) 12: { 13: strError = "Could not access Assembly"; 14: return false; 15: } 16:   17: Type type = assembly.GetType("System.Net.Configuration.SettingsSectionInternal"); 18: if (null == type) 19: { 20: strError = "Could not access internal settings"; 21: return false; 22: } 23:   24: object obj = type.InvokeMember("Section", 25: BindingFlags.Static | BindingFlags.GetProperty | BindingFlags.NonPublic, 26: null, null, new object[] { }); 27:   28: if (null == obj) 29: { 30: strError = "Could not invoke Section member"; 31: return false; 32: } 33:   34: // If it's not already set, set it. 35: FieldInfo fi = type.GetField("useUnsafeHeaderParsing", BindingFlags.NonPublic | BindingFlags.Instance); 36: if (null == fi) 37: { 38: strError = "Could not access useUnsafeHeaderParsing field"; 39: return false; 40: } 41:   42: if (!Convert.ToBoolean(fi.GetValue(obj))) 43: { 44: fi.SetValue(obj, true); 45: } 46:   47: return true; 48: } 49: } 50: }   F# (FSharp): 1: namespace UUHP_FS 2: open System 3: open System.Reflection 4: module CUUHP_FS = 5: let UseUnsafeHeaderParsing(strError : byref<string>) : bool = 6: // 7: let assembly : Assembly = Assembly.GetAssembly(typeof<System.Net.Configuration.SettingsSection>) 8: if (null = assembly) then 9: strError <- "Could not access Assembly" 10: false 11: else 12: 13: let myType : Type = assembly.GetType("System.Net.Configuration.SettingsSectionInternal") 14: if (null = myType) then 15: strError <- "Could not access internal settings" 16: false 17: else 18: 19: let obj : Object = myType.InvokeMember("Section", BindingFlags.Static ||| BindingFlags.GetProperty ||| BindingFlags.NonPublic, null, null, Array.zeroCreate 0) 20: if (null = obj) then 21: strError <- "Could not invoke Section member" 22: false 23: else 24: 25: // If it's not already set, set it. 26: let fi : FieldInfo = myType.GetField("useUnsafeHeaderParsing", BindingFlags.NonPublic ||| BindingFlags.Instance) 27: if(null = fi) then 28: strError <- "Could not access useUnsafeHeaderParsing field" 29: false 30: else 31: 32: if (not(Convert.ToBoolean(fi.GetValue(obj)))) then 33: fi.SetValue(obj, true) 34: 35: // Now return true 36: true VB (Visual Basic): 1: Option Explicit On 2: Option Strict On 3: Imports System 4: Imports System.Reflection 5:   6: Public Class CUUHP_VB 7: Public Shared Function UseUnsafeHeaderParsing(ByRef strError As String) As Boolean 8:   9: Dim assembly As [Assembly] 10: assembly = [assembly].GetAssembly(GetType(System.Net.Configuration.SettingsSection)) 11:   12: If (assembly Is Nothing) Then 13: strError = "Could not access Assembly" 14: Return False 15: End If 16:   17: Dim type As Type 18: type = [assembly].GetType("System.Net.Configuration.SettingsSectionInternal") 19: If (type Is Nothing) Then 20: strError = "Could not access internal settings" 21: Return False 22: End If 23:   24: Dim obj As Object 25: obj = [type].InvokeMember("Section", _ 26: BindingFlags.Static Or BindingFlags.GetProperty Or BindingFlags.NonPublic, _ 27: Nothing, Nothing, New [Object]() {}) 28:   29: If (obj Is Nothing) Then 30: strError = "Could not invoke Section member" 31: Return False 32: End If 33:   34: ' If it's not already set, set it. 35: Dim fi As FieldInfo 36: fi = [type].GetField("useUnsafeHeaderParsing", BindingFlags.NonPublic Or BindingFlags.Instance) 37: If (fi Is Nothing) Then 38: strError = "Could not access useUnsafeHeaderParsing field" 39: Return False 40: End If 41:   42: If (Not Convert.ToBoolean(fi.GetValue(obj))) Then 43: fi.SetValue(obj, True) 44: End If 45:   46: Return True 47: End Function 48: End Class   Technorati Tags: C++,CPP,VB,Visual Basic,F#,FSharp,C#,CSharp,ResponseStatusLine,protocol violation

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  • Sign on Experience with Office 365

    - by Sahil Malik
    SharePoint 2010 Training: more information Office 365 offers two types of identities: · Microsoft Online Services cloud IDs (Cloud Identity): This is the default identity Microsoft provides you, requires no additional setup, you sign up for Office 365 and you are provided a credential. You can sign in using forms based authentication, the password policy etc. for which is stored in the cloud with the Office 365 service. The advantage obviously is no additional setup headache. The disadvantage? Yet another password to remember, and no hope of authenticated single sign on integration using this cloud identity with other services at least in the current version. · Federated IDs (Federated Identity): In companies with on-premises Active Directory, users can sign into Office 365 services using their Active Directory credentials. The corporate Active Directory authenticates the users, and stores and controls the password policy. The advantage here is plenty of single sign on possibilities and better user experience. The downside, more Read full article ....

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  • MDM for Tax Authorities

    - by david.butler(at)oracle.com
    In last week’s MDM blog, we discussed MDM in the Public Sector. I want to continue that thread. After all, no industry faces tougher data quality problems than governmental organizations, and few industries suffer more significant down side consequences to poor operations than local, state and federal governments. One key challenge area is taxation. Tax Authorities face a multitude of IT challenges. Firstly, the data used in tax calculations is increasing in volume and complexity. They must improve service by introducing multi-channel contact centers and self-service capabilities. Security concerns necessitate increasingly sophisticated data protection procedures. And cost constraints are driving Tax Authorities to rely on off-the-shelf software for many of their functional areas. Compounding these issues is the fact that the IT architectures in operation at most revenue and collections agencies are very complex. They typically include multiple, disparate operational and analytical systems across which the sum total of data about individual constituents is fragmented. To make matters more complicated, taxation is not carried out by a single jurisdiction, and often sources of income including employers, investments and other sources of taxable income and deductions must also be tracked and shared among tax authorities. Collectively, these systems are involved in tax assessment and collections, risk analysis, scoring, tracking, auditing and investigation case management. The Problem of Constituent Data Management The infrastructure described above makes it very difficult to create a consolidated representation of a given party. Differing formats and data models mean that a constituent may be represented in one way in one system and in a different way in another. Individual records are frequently inaccurate, incomplete, out of date and/or inconsistent with other records relating to the same constituent. When constituent data must be aggregated and scored, information within each system must be rationalized and normalized so the agency can produce a constituent information file (CIF) that provides a single source of truth about that party. If information about that constituent changes, each system in turn must be updated. There have been many attempts to solve this problem with technology: from consolidating transactional systems to conducting manual systems integration projects and superimposing layers of business intelligence and analytics. All these approaches can be successful in solving a portion of the problem at a specific point in time, but without an enterprise perspective, anything gained is quickly lost again. Oracle Constituent Data Mastering for Tax Authorities: A Single View of the Constituent Oracle has a flexible and long-term solution to the problem of securely integrating and managing constituent data. The Oracle Solution for mastering Constituent Data for Tax Authorities is based on two core product offerings: Oracle Customer Hub and – optionally – Oracle Application Integration Architecture (AIA). Customer Hub is a master data management (MDM) product that centralizes, de-duplicates, and enriches constituent data. It unifies fragmented information without disrupting existing business processes or IT investments. Role based data access and privacy rules guarantee maximum security and privacy. Data is continuously and automatically synchronized with all source systems. With the Oracle Customer Hub managing the master constituent identity, every department can capture transaction activity against the same record, improving reporting accuracy, employee productivity, reliability of constituent analytics, and day-to-day constituent relationships. Oracle Application Integration Architecture provides a collection of core pre-built processes to support out of the box Master Data Governance across Oracle Customer Hub, Siebel CRM, and Oracle E-Business Suite. It also provides a framework to enable MDM integrations with other Oracle and non-Oracle applications. Oracle AIA removes some of the key inhibitors to implementing a service-oriented architecture (SOA) by providing a pre-built SOA-based middleware foundation as well as industry-optimized service oriented applications, all built around a SOA governance model that encourages effective design and reuse. I encourage you to read Oracle Solution for Mastering Constituents Data for Public Sector – Tax Authorities by Roberto Negro. It is an outstanding whitepaper that describes how the Oracle MDM solution allows you to create a unified, reconciled source of high-quality constituent data and gain an accurate single view of each constituent. This foundation enables you to lower the costs associated with data quality and integration and create a tax organization that is efficient, secure and constituent-centric. Also, don’t forget the upcoming webcast on Thursday, February 10th: Deliver Improved Services to Citizens at Lower Cost to your Organization Our Guest Speaker is Ruben Spekle, from Capgemini. He will also provide insight into Public Sector Master Data Management and Case Management implementations including one that was executed for a Dutch Government Agency. If you are interested in how governmental organizations from around the world are using MDM to advance their cause, click here to register for the webcast.

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  • C#/.NET Little Wonders: The Generic Func Delegates

    - by James Michael Hare
    Once again, in this series of posts I look at the parts of the .NET Framework that may seem trivial, but can help improve your code by making it easier to write and maintain. The index of all my past little wonders posts can be found here. Back in one of my three original “Little Wonders” Trilogy of posts, I had listed generic delegates as one of the Little Wonders of .NET.  Later, someone posted a comment saying said that they would love more detail on the generic delegates and their uses, since my original entry just scratched the surface of them. Last week, I began our look at some of the handy generic delegates built into .NET with a description of delegates in general, and the Action family of delegates.  For this week, I’ll launch into a look at the Func family of generic delegates and how they can be used to support generic, reusable algorithms and classes. Quick Delegate Recap Delegates are similar to function pointers in C++ in that they allow you to store a reference to a method.  They can store references to either static or instance methods, and can actually be used to chain several methods together in one delegate. Delegates are very type-safe and can be satisfied with any standard method, anonymous method, or a lambda expression.  They can also be null as well (refers to no method), so care should be taken to make sure that the delegate is not null before you invoke it. Delegates are defined using the keyword delegate, where the delegate’s type name is placed where you would typically place the method name: 1: // This delegate matches any method that takes string, returns nothing 2: public delegate void Log(string message); This delegate defines a delegate type named Log that can be used to store references to any method(s) that satisfies its signature (whether instance, static, lambda expression, etc.). Delegate instances then can be assigned zero (null) or more methods using the operator = which replaces the existing delegate chain, or by using the operator += which adds a method to the end of a delegate chain: 1: // creates a delegate instance named currentLogger defaulted to Console.WriteLine (static method) 2: Log currentLogger = Console.Out.WriteLine; 3:  4: // invokes the delegate, which writes to the console out 5: currentLogger("Hi Standard Out!"); 6:  7: // append a delegate to Console.Error.WriteLine to go to std error 8: currentLogger += Console.Error.WriteLine; 9:  10: // invokes the delegate chain and writes message to std out and std err 11: currentLogger("Hi Standard Out and Error!"); While delegates give us a lot of power, it can be cumbersome to re-create fairly standard delegate definitions repeatedly, for this purpose the generic delegates were introduced in various stages in .NET.  These support various method types with particular signatures. Note: a caveat with generic delegates is that while they can support multiple parameters, they do not match methods that contains ref or out parameters. If you want to a delegate to represent methods that takes ref or out parameters, you will need to create a custom delegate. We’ve got the Func… delegates Just like it’s cousin, the Action delegate family, the Func delegate family gives us a lot of power to use generic delegates to make classes and algorithms more generic.  Using them keeps us from having to define a new delegate type when need to make a class or algorithm generic. Remember that the point of the Action delegate family was to be able to perform an “action” on an item, with no return results.  Thus Action delegates can be used to represent most methods that take 0 to 16 arguments but return void.  You can assign a method The Func delegate family was introduced in .NET 3.5 with the advent of LINQ, and gives us the power to define a function that can be called on 0 to 16 arguments and returns a result.  Thus, the main difference between Action and Func, from a delegate perspective, is that Actions return nothing, but Funcs return a result. The Func family of delegates have signatures as follows: Func<TResult> – matches a method that takes no arguments, and returns value of type TResult. Func<T, TResult> – matches a method that takes an argument of type T, and returns value of type TResult. Func<T1, T2, TResult> – matches a method that takes arguments of type T1 and T2, and returns value of type TResult. Func<T1, T2, …, TResult> – and so on up to 16 arguments, and returns value of type TResult. These are handy because they quickly allow you to be able to specify that a method or class you design will perform a function to produce a result as long as the method you specify meets the signature. For example, let’s say you were designing a generic aggregator, and you wanted to allow the user to define how the values will be aggregated into the result (i.e. Sum, Min, Max, etc…).  To do this, we would ask the user of our class to pass in a method that would take the current total, the next value, and produce a new total.  A class like this could look like: 1: public sealed class Aggregator<TValue, TResult> 2: { 3: // holds method that takes previous result, combines with next value, creates new result 4: private Func<TResult, TValue, TResult> _aggregationMethod; 5:  6: // gets or sets the current result of aggregation 7: public TResult Result { get; private set; } 8:  9: // construct the aggregator given the method to use to aggregate values 10: public Aggregator(Func<TResult, TValue, TResult> aggregationMethod = null) 11: { 12: if (aggregationMethod == null) throw new ArgumentNullException("aggregationMethod"); 13:  14: _aggregationMethod = aggregationMethod; 15: } 16:  17: // method to add next value 18: public void Aggregate(TValue nextValue) 19: { 20: // performs the aggregation method function on the current result and next and sets to current result 21: Result = _aggregationMethod(Result, nextValue); 22: } 23: } Of course, LINQ already has an Aggregate extension method, but that works on a sequence of IEnumerable<T>, whereas this is designed to work more with aggregating single results over time (such as keeping track of a max response time for a service). We could then use this generic aggregator to find the sum of a series of values over time, or the max of a series of values over time (among other things): 1: // creates an aggregator that adds the next to the total to sum the values 2: var sumAggregator = new Aggregator<int, int>((total, next) => total + next); 3:  4: // creates an aggregator (using static method) that returns the max of previous result and next 5: var maxAggregator = new Aggregator<int, int>(Math.Max); So, if we were timing the response time of a web method every time it was called, we could pass that response time to both of these aggregators to get an idea of the total time spent in that web method, and the max time spent in any one call to the web method: 1: // total will be 13 and max 13 2: int responseTime = 13; 3: sumAggregator.Aggregate(responseTime); 4: maxAggregator.Aggregate(responseTime); 5:  6: // total will be 20 and max still 13 7: responseTime = 7; 8: sumAggregator.Aggregate(responseTime); 9: maxAggregator.Aggregate(responseTime); 10:  11: // total will be 40 and max now 20 12: responseTime = 20; 13: sumAggregator.Aggregate(responseTime); 14: maxAggregator.Aggregate(responseTime); The Func delegate family is useful for making generic algorithms and classes, and in particular allows the caller of the method or user of the class to specify a function to be performed in order to generate a result. What is the result of a Func delegate chain? If you remember, we said earlier that you can assign multiple methods to a delegate by using the += operator to chain them.  So how does this affect delegates such as Func that return a value, when applied to something like the code below? 1: Func<int, int, int> combo = null; 2:  3: // What if we wanted to aggregate the sum and max together? 4: combo += (total, next) => total + next; 5: combo += Math.Max; 6:  7: // what is the result? 8: var comboAggregator = new Aggregator<int, int>(combo); Well, in .NET if you chain multiple methods in a delegate, they will all get invoked, but the result of the delegate is the result of the last method invoked in the chain.  Thus, this aggregator would always result in the Math.Max() result.  The other chained method (the sum) gets executed first, but it’s result is thrown away: 1: // result is 13 2: int responseTime = 13; 3: comboAggregator.Aggregate(responseTime); 4:  5: // result is still 13 6: responseTime = 7; 7: comboAggregator.Aggregate(responseTime); 8:  9: // result is now 20 10: responseTime = 20; 11: comboAggregator.Aggregate(responseTime); So remember, you can chain multiple Func (or other delegates that return values) together, but if you do so you will only get the last executed result. Func delegates and co-variance/contra-variance in .NET 4.0 Just like the Action delegate, as of .NET 4.0, the Func delegate family is contra-variant on its arguments.  In addition, it is co-variant on its return type.  To support this, in .NET 4.0 the signatures of the Func delegates changed to: Func<out TResult> – matches a method that takes no arguments, and returns value of type TResult (or a more derived type). Func<in T, out TResult> – matches a method that takes an argument of type T (or a less derived type), and returns value of type TResult(or a more derived type). Func<in T1, in T2, out TResult> – matches a method that takes arguments of type T1 and T2 (or less derived types), and returns value of type TResult (or a more derived type). Func<in T1, in T2, …, out TResult> – and so on up to 16 arguments, and returns value of type TResult (or a more derived type). Notice the addition of the in and out keywords before each of the generic type placeholders.  As we saw last week, the in keyword is used to specify that a generic type can be contra-variant -- it can match the given type or a type that is less derived.  However, the out keyword, is used to specify that a generic type can be co-variant -- it can match the given type or a type that is more derived. On contra-variance, if you are saying you need an function that will accept a string, you can just as easily give it an function that accepts an object.  In other words, if you say “give me an function that will process dogs”, I could pass you a method that will process any animal, because all dogs are animals.  On the co-variance side, if you are saying you need a function that returns an object, you can just as easily pass it a function that returns a string because any string returned from the given method can be accepted by a delegate expecting an object result, since string is more derived.  Once again, in other words, if you say “give me a method that creates an animal”, I can pass you a method that will create a dog, because all dogs are animals. It really all makes sense, you can pass a more specific thing to a less specific parameter, and you can return a more specific thing as a less specific result.  In other words, pay attention to the direction the item travels (parameters go in, results come out).  Keeping that in mind, you can always pass more specific things in and return more specific things out. For example, in the code below, we have a method that takes a Func<object> to generate an object, but we can pass it a Func<string> because the return type of object can obviously accept a return value of string as well: 1: // since Func<object> is co-variant, this will access Func<string>, etc... 2: public static string Sequence(int count, Func<object> generator) 3: { 4: var builder = new StringBuilder(); 5:  6: for (int i=0; i<count; i++) 7: { 8: object value = generator(); 9: builder.Append(value); 10: } 11:  12: return builder.ToString(); 13: } Even though the method above takes a Func<object>, we can pass a Func<string> because the TResult type placeholder is co-variant and accepts types that are more derived as well: 1: // delegate that's typed to return string. 2: Func<string> stringGenerator = () => DateTime.Now.ToString(); 3:  4: // This will work in .NET 4.0, but not in previous versions 5: Sequence(100, stringGenerator); Previous versions of .NET implemented some forms of co-variance and contra-variance before, but .NET 4.0 goes one step further and allows you to pass or assign an Func<A, BResult> to a Func<Y, ZResult> as long as A is less derived (or same) as Y, and BResult is more derived (or same) as ZResult. Sidebar: The Func and the Predicate A method that takes one argument and returns a bool is generally thought of as a predicate.  Predicates are used to examine an item and determine whether that item satisfies a particular condition.  Predicates are typically unary, but you may also have binary and other predicates as well. Predicates are often used to filter results, such as in the LINQ Where() extension method: 1: var numbers = new[] { 1, 2, 4, 13, 8, 10, 27 }; 2:  3: // call Where() using a predicate which determines if the number is even 4: var evens = numbers.Where(num => num % 2 == 0); As of .NET 3.5, predicates are typically represented as Func<T, bool> where T is the type of the item to examine.  Previous to .NET 3.5, there was a Predicate<T> type that tended to be used (which we’ll discuss next week) and is still supported, but most developers recommend using Func<T, bool> now, as it prevents confusion with overloads that accept unary predicates and binary predicates, etc.: 1: // this seems more confusing as an overload set, because of Predicate vs Func 2: public static SomeMethod(Predicate<int> unaryPredicate) { } 3: public static SomeMethod(Func<int, int, bool> binaryPredicate) { } 4:  5: // this seems more consistent as an overload set, since just uses Func 6: public static SomeMethod(Func<int, bool> unaryPredicate) { } 7: public static SomeMethod(Func<int, int, bool> binaryPredicate) { } Also, even though Predicate<T> and Func<T, bool> match the same signatures, they are separate types!  Thus you cannot assign a Predicate<T> instance to a Func<T, bool> instance and vice versa: 1: // the same method, lambda expression, etc can be assigned to both 2: Predicate<int> isEven = i => (i % 2) == 0; 3: Func<int, bool> alsoIsEven = i => (i % 2) == 0; 4:  5: // but the delegate instances cannot be directly assigned, strongly typed! 6: // ERROR: cannot convert type... 7: isEven = alsoIsEven; 8:  9: // however, you can assign by wrapping in a new instance: 10: isEven = new Predicate<int>(alsoIsEven); 11: alsoIsEven = new Func<int, bool>(isEven); So, the general advice that seems to come from most developers is that Predicate<T> is still supported, but we should use Func<T, bool> for consistency in .NET 3.5 and above. Sidebar: Func as a Generator for Unit Testing One area of difficulty in unit testing can be unit testing code that is based on time of day.  We’d still want to unit test our code to make sure the logic is accurate, but we don’t want the results of our unit tests to be dependent on the time they are run. One way (of many) around this is to create an internal generator that will produce the “current” time of day.  This would default to returning result from DateTime.Now (or some other method), but we could inject specific times for our unit testing.  Generators are typically methods that return (generate) a value for use in a class/method. For example, say we are creating a CacheItem<T> class that represents an item in the cache, and we want to make sure the item shows as expired if the age is more than 30 seconds.  Such a class could look like: 1: // responsible for maintaining an item of type T in the cache 2: public sealed class CacheItem<T> 3: { 4: // helper method that returns the current time 5: private static Func<DateTime> _timeGenerator = () => DateTime.Now; 6:  7: // allows internal access to the time generator 8: internal static Func<DateTime> TimeGenerator 9: { 10: get { return _timeGenerator; } 11: set { _timeGenerator = value; } 12: } 13:  14: // time the item was cached 15: public DateTime CachedTime { get; private set; } 16:  17: // the item cached 18: public T Value { get; private set; } 19:  20: // item is expired if older than 30 seconds 21: public bool IsExpired 22: { 23: get { return _timeGenerator() - CachedTime > TimeSpan.FromSeconds(30.0); } 24: } 25:  26: // creates the new cached item, setting cached time to "current" time 27: public CacheItem(T value) 28: { 29: Value = value; 30: CachedTime = _timeGenerator(); 31: } 32: } Then, we can use this construct to unit test our CacheItem<T> without any time dependencies: 1: var baseTime = DateTime.Now; 2:  3: // start with current time stored above (so doesn't drift) 4: CacheItem<int>.TimeGenerator = () => baseTime; 5:  6: var target = new CacheItem<int>(13); 7:  8: // now add 15 seconds, should still be non-expired 9: CacheItem<int>.TimeGenerator = () => baseTime.AddSeconds(15); 10:  11: Assert.IsFalse(target.IsExpired); 12:  13: // now add 31 seconds, should now be expired 14: CacheItem<int>.TimeGenerator = () => baseTime.AddSeconds(31); 15:  16: Assert.IsTrue(target.IsExpired); Now we can unit test for 1 second before, 1 second after, 1 millisecond before, 1 day after, etc.  Func delegates can be a handy tool for this type of value generation to support more testable code.  Summary Generic delegates give us a lot of power to make truly generic algorithms and classes.  The Func family of delegates is a great way to be able to specify functions to calculate a result based on 0-16 arguments.  Stay tuned in the weeks that follow for other generic delegates in the .NET Framework!   Tweet Technorati Tags: .NET, C#, CSharp, Little Wonders, Generics, Func, Delegates

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  • A big flat text file or a HTML site for language documentation?

    - by Bad Sector
    A project of mine is a small embeddable Tcl-like scripting language, LIL. While i'm mostly making it for my own use, i think it is interesting enough for others to use, so i want it to have a nice (but not very "wordy") documentation. So far i'm using a single flat readme.txt file. It explains the language's syntax, features, standard functions, how to use the C API, etc. Also it is easy to scan and read in almost every environment out there, from basic text-only terminals to full-fledged high-end graphical desktop environments. However, while i tried to keep things nicely formatted (as much as this is possible in plain text), i still think that being a big (and growing) wall of text, it isn't as easy on the eyes as it could be. Also i feel that sometimes i'm not writing as much as i want in order to avoid expanding the text too much. So i thought i could use another project of mine, QuHelp, which is basically a help site generator for sites like this one with a sidebar that provides a tree of topics/subtopics and offline full text search. With this i can use HTML to format the documentation and if i use QuHelp for some other project that uses LIL, i can import LIL's documentation as part of the other project's documentation. However converting the existing documentation to QuHelp/HTML isn't a small task, especially when it comes to functions (i'll need to put more detail on them than what currently exists in the readme.txt file). Also it loses the wide range of availability that it currently has (even if QuHelp's generated code degrades gracefully down to console-only web browsers, plain text is readable from everywhere, including from popular editors such as Vim and Emacs - i had someone once telling me that he likes LIL's documentation because it is readable without leaving his editor). So, my question is simply this: should i keep the documentation as it is now in the form of a single readme.txt file or should i convert it to something like the site i mentioned above? There is also the option to do both, but i'm not sure if i'll be able to always keep them in sync or if it is worth the effort. After asking around in IRC i've got mixed answers: some liked the wide availability of the single text file, others said that it is looks as bad as a man page (personally i don't mind that - i can read man pages just fine - but other people might have issues reading them). What do you think?

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  • What&rsquo;s new in RadChart for 2010 Q1 (Silverlight / WPF)

    Greetings, RadChart fans! It is with great pleasure that I present this short highlight of our accomplishments for the Q1 release :). Weve worked very hard to make the best silverlight and WPF charting product even better. Here is some of what we did during the past few months.   1) Zooming&Scrolling and the new sampling engine: Without a doubt one of the most important things we did. This new feature allows you to bind your chart to a very large set of data with blazing performance. Dont take my word for it give it a try!   2) New Smart Label Positioning and Spider-like labels feature: This new feature really helps with very busy graphs. You can play with the different settings we offer in this example.   3) Sorting and Filtering. Much like our RadGridview control the chart now allows you to sort and filter your data out of the box with a single line of code!   4) Legend improvements Weve also been paying attention to those of you who wanted a much improved legend. It is now possible to customize the look and feel of legend items and legend position with a single click.   5) Custom palette brushes. You have told us that you want to easily customize all palette colors using a single clean API from both XAML and code behind. The new custom palette brushes API does exactly that.   There are numerous other improvements as well, as much improved themes, performance optimizations and other features that we did. If you want to dig in further check the release notes and changes and backwards compatibility topics.   Feel free to share the pains and gains of working with RadChart. Our team is always open to receiving constructive feedback and beer :-)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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  • Gerrit, git and reviewing whole branch

    - by liori
    I'm now learning Gerrit (which is the first code review tool I use). Gerrit requires a reviewed change to consist of a single commit. My feature branch has about 10 commits. The gerrit-prefered way is to squash those 10 commits into a single one. However this way if the commit will be merged into the target branch, the internal history of that feature branch will be lost. For example, I won't be able to use git-bisect to bisect into those commits. Am I right? I am a little bit worried about this state of things. What is the rationale for this choice? Is there any way of doing this in Gerrit without losing history?

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  • How to build a Singleton-like dependency injector replacement (Php)

    - by Erparom
    I know out there are a lot of excelent containers, even frameworks almost entirely DI based with good strong IoC classes. However, this doesn't help me to "define" a new pattern. (This is Php code but understandable to anyone) Supose we have: //Declares the singleton class bookSingleton { private $author; private static $bookInstance; private static $isLoaned = FALSE; //The private constructor private function __constructor() { $this->author = "Onecrappy Writer Ofcheap Novels"; } //Sets the global isLoaned state and also gets self instance public static function loanBook() { if (self::$isLoaned === FALSE) { //Book already taken, so return false return FALSE; } else { //Ok, not loaned, lets instantiate (if needed and loan) if (!isset(self::$bookInstance)) { self::$bookInstance = new BookSingleton(); } self::$isLoaned = TRUE; } } //Return loaned state to false, so another book reader can take the book public function returnBook() { $self::$isLoaned = FALSE; } public function getAuthor() { return $this->author; } } Then we get the singelton consumtion class: //Consumes the Singleton class BookBorrower() { private $borrowedBook; private $haveBookState; public function __construct() { this->haveBookState = FALSE; } //Use the singelton-pattern behavior public function borrowBook() { $this->borrowedBook = BookSingleton::loanBook(); //Check if was successfully borrowed if (!this->borrowedBook) { $this->haveBookState = FALSE; } else { $this->haveBookState = TRUE; } } public function returnBook() { $this->borrowedBook->returnBook(); $this->haveBookState = FALSE; } public function getBook() { if ($this->haveBookState) { return "The book is loaned, the author is" . $this->borrowedbook->getAuthor(); } else { return "I don't have the book, perhaps someone else took it"; } } } At last, we got a client, to test the behavior function __autoload($class) { require_once $class . '.php'; } function write ($whatever,$breaks) { for($break = 0;$break<$breaks;$break++) { $whatever .= "\n"; } echo nl2br($whatever); } write("Begin Singleton test", 2); $borrowerJuan = new BookBorrower(); $borrowerPedro = new BookBorrower(); write("Juan asks for the book", 1); $borrowerJuan->borrowBook(); write("Book Borrowed? ", 1); write($borrowerJuan->getAuthorAndTitle(),2); write("Pedro asks for the book", 1); $borrowerPedro->borrowBook(); write("Book Borrowed? ", 1); write($borrowerPedro->getAuthorAndTitle(),2); write("Juan returns the book", 1); $borrowerJuan->returnBook(); write("Returned Book Juan? ", 1); write($borrowerJuan->getAuthorAndTitle(),2); write("Pedro asks again for the book", 1); $borrowerPedro->borrowBook(); write("Book Borrowed? ", 1); write($borrowerPedro->getAuthorAndTitle(),2); This will end up in the expected behavior: Begin Singleton test Juan asks for the book Book Borrowed? The book is loaned, the author is = Onecrappy Writer Ofcheap Novels Pedro asks for the book Book Borrowed? I don't have the book, perhaps someone else took it Juan returns the book Returned Book Juan? I don't have the book, perhaps someone else took it Pedro asks again for the book Book Borrowed? The book is loaned, the author is = Onecrappy Writer Ofcheap Novels So I want to make a pattern based on the DI technique able to do exactly the same, but without singleton pattern. As far as I'm aware, I KNOW I must inject the book inside "borrowBook" function instead of taking a static instance: public function borrowBook(BookNonSingleton $book) { if (isset($this->borrowedBook) || $book->isLoaned()) { $this->haveBook = FALSE; return FALSE; } else { $this->borrowedBook = $book; $this->haveBook = TRUE; return TRUE; } } And at the client, just handle the book: $borrowerJuan = new BookBorrower(); $borrowerJuan-borrowBook(new NonSingletonBook()); Etc... and so far so good, BUT... Im taking the responsability of "single instance" to the borrower, instead of keeping that responsability inside the NonSingletonBook, that since it has not anymore a private constructor, can be instantiated as many times... making instances on each call. So, What does my NonSingletonBook class MUST be in order to never allow borrowers to have this same book twice? (aka) keep the single instance. Because the dependency injector part of the code (borrower) does not solve me this AT ALL. Is it needed the container with an "asShared" method builder with static behavior? No way to encapsulate this functionallity into the Book itself? "Hey Im a book and I shouldn't be instantiated more than once, I'm unique"

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  • Using branchs for a mini project or module of project: Good practice?

    - by TheLQ
    In my repo I have 3 closely related mini projects: 1 server and 2 clients. They are all quite small (<3 files each). Since they are so small and so closely related I just dropped them in folders in one single repo. However now that I know I can't clone a single directory in my VCS of choice (Mercurial), I'm considering splitting them up. However I'm confused about general best practice: Is it okay to put different small projects in different branches, or should they all go in different repos? I'm currently leaning towards branching since I can't easily splice out the file history of the different projects but then your using a feature in a way it wasn't meant to be used.

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