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• LINQ: Single vs. First

  - by Paulo Morgado

  I’ve witnessed and been involved in several discussions around the correctness or usefulness of the Single method in the LINQ API. The most common argument is that you are querying for the first element on the result set and an exception will be thrown if there’s more than one element. The First method should be used instead, because it doesn’t throw if the result set has more than one item. Although the documentation for Single states that it returns a single, specific element of a sequence of values, it actually returns THE single, specific element of a sequence of ONE value. One you use the Single method in your code you are asserting that your query will result in a scalar result instead of a result set of arbitrary length. On the other hand, the documentation for First states that it returns the first element of a sequence of arbitrary length. Imagine you want to catch a taxi. You go the the taxi line and catch the FIRST one, no matter how many are there. On the other hand, if you go the the parking lot to get your car, you want the SINGLE one specific car that’s yours. If your “query” “returns” more than one car, it’s an exception. Either because it “returned” not only your car or you happen to have more than one car in that parking lot. In either case, you can only drive one car at once and you’ll need to refine your “query”.

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• Information Indepth Newsletter - Linux Edition

  - by Paulo Folgado

  INFORMATION INDEPTH NEWSLETTERLinux Edition February 2011 Stay Connected:  NEWS Now Available: Oracle Linux 6 Get the latest release of Oracle Linux 6, which includes Unbreakable Enterprise Kernel.Download Oracle Linux 6 Read More Customers Succeed by Using Oracle Exadata with Oracle Linux Watch IT executives from Bank of America, Linkshare, and Johns Hopkins as they talk about the business challenges they faced and why they chose to use Oracle Linux along with Oracle Exadata as the solution. Watch Now Video Interview: Oracle Senior Vice President Wim Coekaerts Watch Wim Coekaerts, senior vice president, Linux and Virtualization Engineering, as he talks about use cases for Oracle VM Templates as well as the Unbreakable Enterprise Kernel for Linux.Watch Now Hot Off the Press: Migrate Your IBM AIX Environment to Oracle Linux This new white paper provides recommendations for planning and implementing the migration of applications from an IBM Power System running AIX to Oracle's Sun Fire X4800 Server with Intel Xeon 7560 Processor running Oracle Linux 5.5.Read More  Back to Top BLOGOSPHERE Just Launched: The Oracle Linux Blog Follow our new Oracle Linux blog  to hear the latest updates, product news, upcoming events, and all the latest happenings, directly from the Linux team at Oracle. Back to Top TECH DIVE NEW: Linux/Oracle Solaris CommandComparo Site from Oracle Technology NetworkThis site gives equivalent command syntax in Oracle Solaris 10 and Oracle Enterprise Linux 5 for common administrative tasks--focusing particularly on tasks that have tricky syntax or that you frequently need to double check. It acts as a quick reference for administrators who operate in these two OS environments. Free Download: Oracle Linux Release 5.6Did you know that by using Oracle Linux 5.5 or 5.6 along with the Unbreakable Enterprise Kernel, you can get all the benefits of Linux mainline kernel 2.6.32 and more, right now, without the need to reinstall or migrate to a new operating system such as RHEL6?Read Release NotesDownload Oracle Linux 5.6 LSB 4.0 Certification Completed for Oracle Linux 5.5Oracle Linux 5.5 with Unbreakable Enterprise Kernel successfully completed the LSB 4.0 certification.  Back to Top WEBCASTS Boost Your Linux Performance with Oracle's Enhancements in Infiniband and RDSRegister to hear Director of Kernel Engineering Chris Mason cover scalability and performance improvements in Linux environment. Get the Facts Oracle's Unbreakable Enterprise KernelSVP Wim Coekaerts and Senior Director Monica Kumar cover the facts about and benefits of using Unbreakable Enterprise Kernel.  View Other Webcasts on Demand   Back to Top EVENTS Collaborate 2011April 10-14 Orlando, Florida Cloud Summit Events, WorldwideVarious dates (check the city for date/time of event) Datacenter Efficiency Events WorldwideThese events include Linux and Oracle VM sessions.Various dates (check the city for date/time of event) Virtualization Events in North America Find an Oracle Event  Back to Top EDUCATION Get Oracle Linux Certified from Oracle University Oracle University offers courses in both Oracle Linux and the administration of Oracle Database on Linux.  Back to Top CUSTOMER SPOTLIGHT Pella Corporation Improves IT Performance and Efficiency with Oracle Linux and Oracle VM To improve IT performance and efficiency and lower operational costs, Pella Corporation, has standardized on Oracle VM and Oracle Linux. Read More Disney Store Deploys POS in 330 Stores and 7 Countries on Oracle Linux Disney Store is running 1,500 registers worldwide on a broad Oracle technology software stack including Oracle Database 11g, Oracle Fusion Middleware, and Oracle Linux. Read More Back to Top PARTNER SPOTLIGHT Emulex and Oracle Announce Data Integrity Features The Unbreakable Enterprise Kernel provides data integrity checking between Oracle Database applications and Emulex 8Gb/s LightPulse Fibre Channel Host Bus Adapters. Read More Dell Inc. Dell Inc. tested and validated configurations support Oracle Linux. Back to Top STAY IN TOUCH Follow @ORCL_Linux on Twitter for the latest penguin tweets Bookmark Oracle.com/Linux Read the Oracle Linux blog Back to Top  Oracle Information InDepth newsletters bring targeted news, articles, customer stories, and special offers to business people who want to find out how to streamline enterprise information management, measure results, improve business processes, and communicate a single truth to their constituents. Please send questions or comments to [email protected]. For answers to questions about subscribing, unsubscribing, and managing your Oracle e-mail communications preferences, please see the Oracle E-Mail Communications page. Copyright © 2011, Oracle Corporation and/or its affiliates. All rights reserved. Oracle is a registered trademark of Oracle Corporation and/or its affiliates. Other names may be trademarks of their respective owners. This document is provided for information purposes only, and the contents hereof are subject to change without notice. This document is not warranted to be error-free, nor is it subject to any other warranties or conditions, whether expressed orally or implied in law, including implied warranties and conditions of merchantability or fitness for a particular purpose. We specifically disclaim any liability with respect to this document, and no contractual obligations are formed either directly or indirectly by this document. This document may not be reproduced or transmitted in any form or by any means, electronic or mechanical, for any purpose, without our prior written permission. 

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• C# 5.0 Async/Await Demo Code

  - by Paulo Morgado

  I’ve published the sample code I use to demonstrate the use of async/await in C# 5.0. You can find it here. Projects PauloMorgado.AyncDemo.WebServer This project is a simple web server implemented as a console application using Microsoft ASP.NET Web API self hosting and serves an image (with a delay) that is accessed by the other projects. This project has a dependency on Json.NET due to the fact the the Microsoft ASP.NET Web API hosting has a dependency on Json.NET. The application must be run on a command prompt with administrative privileges or a urlacl must be added to allow the use of the following command: netsh http add urlacl url=http://+:9090/ user=machine\username To remove the urlacl, just use the following command: netsh http delete urlacl url=http://+:9090/ PauloMorgado.AsyncDemo.WindowsForms This Windows Forms project contains three regions that must be uncommented one at a time: Sync with WebClient This code retrieves the image through a synchronous call using the WebClient class. Async with WebClient This code retrieves the image through an asynchronous call using the WebClient class. Async with HttpClient with cancelation This code retrieves the image through an asynchronous call with cancelation using the HttpClient class. PauloMorgado.AsyncDemo.Wpf This WPF project contains three regions that must be uncommented one at a time: Sync with WebClient This code retrieves the image through a synchronous call using the WebClient class. Async with WebClient This code retrieves the image through an asynchronous call using the WebClient class. Async with HttpClient with cancelation This code retrieves the image through an asynchronous call with cancelation using the HttpClient class.

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• Innovative SPARC: Lighting a Fire Under Oracle's New Hardware Business

  - by Paulo Folgado

  "There's a certain level of things you can do with commercially available parts," says Oracle Executive Vice President Mike Splain. But, he notes, you can do so much more if you design the parts yourself. Mike Splain,EVP, OracleYou can, for example, design cryptographic accelerators into your microprocessors so customers can run their networks fully encrypted if they choose.Of course, it helps if you've already built multiple processing "cores" into those chips so they can handle all that encrypting and decrypting while still getting their other work done.System on a ChipAs the leader of Oracle Microelectronics, Mike knows how implementing clever innovations in silicon can give systems a real competitive advantage.The SPARC microprocessors that his team designed at Sun pioneered the concept of multiple cores several years ago, and the UltraSPARC T2 processor--the industry's first "system on a chip"--packs up to eight cores per chip, each running as many as eight threads at once. That's the most cores and threads of any general-purpose processor. Looking back, Mike points out that the real value of large enterprise-class servers was their ability to run a lot of very large applications in parallel."The beauty of our CMT [chip multi-threading] machines is you can get that same kind of parallel-processing capability at a much lower cost and in a much smaller footprint," he says.The Whole StackWhat has Mike excited these days is that suddenly the opportunity to innovate is much bigger as part of Oracle."In my group, we used to look up the software stack and say, 'We can do any innovation we want, provided the only thing we have to change is what's in the Solaris operating system'--or maybe Java," he says. "If we wanted to change things beyond that, we'd have to go outside the walls of Sun and we'd have to convince the vendors: 'You have to align with us, you have to test with us, you have to build for us, and then you'll reap the benefits.' Now we get access to the entire stack. We can look all the way through the stack and say, 'Okay, what would make the database go faster? What would make the middleware go faster?'"Changing the WorldMike and his microelectronics team also like the fact that Oracle is not just any software company. We're #1 in database, middleware, business intelligence, and more."We're like all the other engineers from Sun; we believe we can change the world, if we can just figure out how to get people to pay attention to us," he says. "Now there's a mechanism at Oracle--much more so than we ever had at Sun."He notes, too, that every innovation in SPARC has involved some combination of hardware and softwareoptimization."Take our cryptography framework, for example. Sure, we can accelerate rapidly, but the Solaris OS has to provide the right set of interfaces that applications can tap into," Mike says. "Same thing with our multicore architecture. We have to have software that can utilize all those threads and run in parallel." His engineers, he points out, have never been interested in producing chips that sell as mere components."Our chips are always designed to go into systems and be combined with various pieces of software," he says. "Our job is to enable the creation of systems."

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• Oracle anuncia resultados de Q3 FY10

  - by Paulo Folgado

  Oracle Reports GAAP EPS of $0.23, Non-GAAP EPS of $0.38New Software Licenses Up 13%, Applications New Licenses Up 21%Oracle Corporation today announced fiscal 2010 Q3 GAAP total revenues were up 17% to $6.4 billion, while non-GAAP total revenues were up 18% to $6.5 billion. Excluding the impact of Sun Microsystems, Inc., which Oracle acquired on January 26, 2010, GAAP total revenue grew 7%. GAAP new software license revenues were up 13% to $1.7 billion, and up 10% to $1.7 billion excluding Sun. GAAP software license updates and product support revenues were up 13% to $3.3 billion, while non-GAAP software license updates and product support revenues were up 12% to $3.3 billion. GAAP operating income was down 5% to $1.8 billion, and GAAP operating margin was 29%. Non-GAAP operating income was up 13% to $2.9 billion, and non-GAAP operating margin was 45%. GAAP net income was down 10% to $1.2 billion, while non-GAAP net income was up 9% to $1.9 billion. GAAP earnings per share were $0.23, down 11% compared to last year while non-GAAP earnings per share were up 9% to $0.38. GAAP operating cash flow on a trailing twelve-month basis was $8.2 billion. "Our solid top line growth, coupled with disciplined expense management, was key in generating $8.0 billion of free cash flow over the last twelve months," said Oracle CFO Jeff Epstein."The Sun integration is going even better than we expected," said Oracle President, Safra Catz. "We believe that Sun will make a significant contribution to our fourth quarter earnings per share as well as meet the profitability goals we set for next year.""Exadata is the fastest growing product in Oracle's history," said Oracle President, Charles Phillips. "Introduced a little over a year ago, the Exadata pipeline is now approaching $400 million with Q4 bookings forecast at nearly $100 million. This strengthens both sales growth and profitability in our Sun server and storage businesses.""Every quarter we grab huge chunks of market share from SAP," said Oracle CEO, Larry Ellison. "SAP's most recent quarter was the best quarter of their year, only down 15%, while Oracle's application sales were up 21%. But SAP is well ahead of us in the number of CEOs for this year, announcing their third and fourth, while we only had one."In addition, Oracle's Board of Directors declared a cash dividend of $0.05 per share of outstanding common stock to be paid to stockholders of record as of the close of business on April 14, 2010, with a payment date of May 5, 2010. Future declarations of quarterly dividends and the establishment of future record and payment dates are subject to the final determination of Oracle's Board of Directors.Q3 Earnings Conference Call and WebcastOracle will hold a conference call and web broadcast today to discuss these results at 2:00 p.m. Pacific. You may listen to the call by dialing (800) 214-0694 or (719) 955-1425, Passcode: 567035. To access the live Web broadcast of this event, please visit the Oracle Investor Relations Web site at http://www.oracle.com/investor.

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• Partner Induction Bootcamp - Technology Guided Learning Path

  - by Paulo Folgado

  Partner Induction Bootcamp - TechnologyGuided Learning Path Em suporte do nosso objectivo de promover a auto-suficiência dos nossos parceiros, temos o prazer de anunciar o lançamento do novo plano de formação: EMEA Partner Induction Bootcamp Technology. Este plano de formação (Guided Learning Path) cobre não só uma introdução ao "stack" tecnológico Oracle, mas também às Técnicas de Vendas e Processos de Negócio, visando aumentar a capacidade das equipas de Vendas dos Parceiros na identificação de oportunidades de negócio e consequentemente incrementar o seu negócio com a Oracle. Este Plano de Formação contempla 2 níveis: Nível 1 - Awareness: 17 sessões diferentes de eLearning pré-gravadas cobrindo todo o "stack" tecnológicoOracle. Estão organizadas em 3 grandes módulos: Base de Dados e Opções, Fusion Middleware e BI. No final de cada módulo, existe uma prova de avaliação. Nível 2 - Proficiency: Uma formação de 2 dias em sala de aula para melhorar e praticar as técnicas de gestão de oportunidades de negócio. Estas formações estão disponíveis apenas aos membros registados no OPN que trabalham com Tecnologia Oracle. Para mais informação sobre o the EMEA Partner Induction Bootcamp Technology, clique aqui.

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• Globalization, Localization And Why My Application Stopped Launching

  - by Paulo Morgado

  When I was localizing a Windows Phone application I was developing, I set the argument on the constructor of the AssemblyCultureAttribute for the neutral culture (en-US in this particular case) for my application. As it was late at night (or early in the dawn ) I went to sleep and, on the next day, the application wasn’t launching although it compiled just fine. I’ll have to confess that it took me a couple of nights to figure out what I had done to my application. Have you figured out what I did wrong? The documentation for the AssemblyCultureAttribute states that: The attribute is used by compilers to distinguish between a main assembly and a satellite assembly. A main assembly contains code and the neutral culture's resources. A satellite assembly contains only resources for a particular culture, as in [assembly:AssemblyCultureAttribute("de")]. Putting this attribute on an assembly and using something other than the empty string ("") for the culture name will make this assembly look like a satellite assembly, rather than a main assembly that contains executable code. Labeling a traditional code library with this attribute will break it, because no other code will be able to find the library's entry points at runtime. So, what I did was marking the once main assembly as a satellite assembly for the en-US culture which made it impossible to find its entry point. To set the the neutral culture for the assembly resources I should haveused (and eventually did) the NeutralResourcesLanguageAttribute. According to its documentation: The NeutralResourcesLanguageAttribute attribute informs the ResourceManager of the application's default culture, and also informs the ResourceManager that the default culture's resources are found in the main application assembly. When looking up resources in the same culture as the default culture, the ResourceManager automatically uses the resources located in the main assembly instead of searching for a satellite assembly. This improves lookup performance for the first resource you load, and can reduce your working set.

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• C# 4.0: Alternative To Optional Arguments

  - by Paulo Morgado

  Like I mentioned in my last post, exposing publicly methods with optional arguments is a bad practice (that’s why C# has resisted to having it, until now). You might argument that your method or constructor has to many variants and having ten or more overloads is a maintenance nightmare, and you’re right. But the solution has been there for ages: have an arguments class. The arguments class pattern is used in the .NET Framework is used by several classes, like XmlReader and XmlWriter that use such pattern in their Create methods, since version 2.0: XmlReaderSettings settings = new XmlReaderSettings(); settings.ValidationType = ValidationType.Auto; XmlReader.Create("file.xml", settings); With this pattern, you don’t have to maintain a long list of overloads and any default values for properties of XmlReaderSettings (or XmlWriterSettings for XmlWriter.Create) can be changed or new properties added in future implementations that won’t break existing compiled code. You might now argue that it’s too much code to write, but, with object initializers added in C# 3.0, the same code can be written like this: XmlReader.Create("file.xml", new XmlReaderSettings { ValidationType = ValidationType.Auto }); Looks almost like named and optional arguments, doesn’t it? And, who knows, in a future version of C#, it might even look like this: XmlReader.Create("file.xml", new { ValidationType = ValidationType.Auto });

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• The Evolution Of C#

  - by Paulo Morgado

  The first release of C# (C# 1.0) was all about building a new language for managed code that appealed, mostly, to C++ and Java programmers. The second release (C# 2.0) was mostly about adding what wasn’t time to built into the 1.0 release. The main feature for this release was Generics. The third release (C# 3.0) was all about reducing the impedance mismatch between general purpose programming languages and databases. To achieve this goal, several functional programming features were added to the language and LINQ was born. Going forward, new trends are showing up in the industry and modern programming languages need to be more: Declarative With imperative languages, although having the eye on the what, programs need to focus on the how. This leads to over specification of the solution to the problem in hand, making next to impossible to the execution engine to be smart about the execution of the program and optimize it to run it more efficiently (given the hardware available, for example). Declarative languages, on the other hand, focus only on the what and leave the how to the execution engine. LINQ made C# more declarative by using higher level constructs like orderby and group by that give the execution engine a much better chance of optimizing the execution (by parallelizing it, for example). Concurrent Concurrency is hard and needs to be thought about and it’s very hard to shoehorn it into a programming language. Parallel.For (from the parallel extensions) looks like a parallel for because enough expressiveness has been built into C# 3.0 to allow this without having to commit to specific language syntax. Dynamic There was been lots of debate on which ones are the better programming languages: static or dynamic. The fact is that both have good qualities and users of both types of languages want to have it all. All these trends require a paradigm switch. C# is, in many ways, already a multi-paradigm language. It’s still very object oriented (class oriented as some might say) but it can be argued that C# 3.0 has become a functional programming language because it has all the cornerstones of what a functional programming language needs. Moving forward, will have even more. Besides the influence of these trends, there was a decision of co-evolution of the C# and Visual Basic programming languages. Since its inception, there was been some effort to position C# and Visual Basic against each other and to try to explain what should be done with each language or what kind of programmers use one or the other. Each language should be chosen based on the past experience and familiarity of the developer/team/project/company and not by particular features. In the past, every time a feature was added to one language, the users of the other wanted that feature too. Going forward, when a feature is added to one language, the other will work hard to add the same feature. This doesn’t mean that XML literals will be added to C# (because almost the same can be achieved with LINQ To XML), but Visual Basic will have auto-implemented properties. Most of these features require or are built on top of features of the .NET Framework and, the focus for C# 4.0 was on dynamic programming. Not just dynamic types but being able to talk with anything that isn’t a .NET class. Also introduced in C# 4.0 is co-variance and contra-variance for generic interfaces and delegates. Stay tuned for more on the new C# 4.0 features.

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• Distrilogie muda de nome para Altimate

  - by Paulo Folgado

   O Grupo Distrilogie entra numa nova dimensão O Distribuidor de valor acrescentado em TI aposta numa mudança radical: muda de nome e de imagem, para passar a ser Altimate - Smart IT Distributor   Lisboa, 5 de Maio de 2010 - Para o grupo de reconhecido sucesso, o principal ponto forte está na mudança: a partir de hoje, a Distrilogie Portugal, Espanha, Bélgica, Luxemburgo, Holanda e França, bem como todas as suas aquisições, deixam o seu nome e formam o novo grupo Altimate. Na Península Ibérica, esta mudança afecta o grupo Distrilogie Iberia, formado pela Distrilogie Portugal, Distrilogie Espanha e Mambo Technology, o distribuidor especializado em segurança do grupo.   Altimate: uma marca com grandes ambições europeias Esta mudança assenta na vontade de reforçar um grupo de longo e frutífero trajecto, que conta com os melhores talentos e uma diversificada gama de soluções altamente complementares. "Continuar a crescer ao nosso ritmo (+27% este ano), em tempos como os de agora, passa por desenvolver todas as sinergias possíveis dentro do nosso grupo, e não só a nível nacional e regional, mas também pan-europeu. O nosso grupo goza, a nível internacional, de uma grande diversidade de soluções, que se complementam entre si. É uma riqueza que queremos aproveitar e desenvolver a nível de cada país, consolidando o nosso portfólio pan-europeu. Trata-se de um ponto fundamental para o crescimento futuro, agora que o mercado dos principais fabricantes tende à concentração", explica Alexis Brabant, Director-Geral da Altimate Iberia e membro do Comité Executivo Europeu do Grupo Altimate.   Por outro lado, a criação da Altimate assenta numa ambiciosa estratégia de expansão e consolidação por todo o continente. Entre outros objectivos fundamentais, a Altimate pretende estabelecer-se em 4 novos países da União Europeia nos próximos 2 anos. Assim o ilustra Patrice Arzillier, fundador da Distrilogie e PDG do grupo Altimate: "Graças ao apoio incondicional do nosso accionista DCC, o nosso grupo conheceu um desenvolvimento notável. Hoje, a criação da Altimate marca uma nova etapa de crescimento combinando solidez económica, ambição de expansão europeia e manutenção dos nossos valores fundadores."  Altimate: alta proximidade Tal como a Distrilogie, o novo grupo Altimate tem como missão o sucesso dos seus parceiros e fabricantes. Para a cumprir, continuará a potenciar a proximidade das suas equipas - altamente qualificadas e voltadas para a identificação das soluções mais inteligentes, inovadoras e adequadas.  Para mais informações acerca da Altimate, visite o novo site . http://www.altimate-group.com  

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• EMEA OPN Partner Specialization Awards

  - by Paulo Folgado

  Announcing the EMEA OPN Partner Specialization AwardsPartner recognition is a fundamental part of OPN Specialized, and we are delighted to announce a new award program for partners in EMEA, the EMEA OPN Partner Specialization Awards. With these awards we will recognize the partners who have specialized their business with Oracle and who are delivering real customer value. Partners who have achieved one or more Specializations in OPN are eligible to submit nominations to become a Partner of the Year for 2010. Our winners will gain valuable prestige and recognition, and will be awarded in a ceremony at Oracle OpenWorld on 19 September 2010. Seven award categories are available: Technology Partner of the Year Applications Partner of the Year ISV Partner of the Year Midsize Partner of the Year Industry Partner of the Year Value Added Distributor of the Year Accelerate Partner of the Year We encourage you to submit your nominations today! Nominations are open from March 1 to June 11, 2010 For more information on the award categories and criteria, please visit the awards page on the OPN Portal here. 

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• C# 4.0: Covariance And Contravariance In Generics Made Easy

  - by Paulo Morgado

  In my last post, I went through what is variance in .NET 4.0 and C# 4.0 in a rather theoretical way. Now, I’m going to try to make it a bit more down to earth. Given: class Base { } class Derived : Base { } Such that: Trace.Assert(typeof(Base).IsClass && typeof(Derived).IsClass && typeof(Base).IsGreaterOrEqualTo(typeof(Derived))); Covariance interface ICovariantIn<out T> { } Trace.Assert(typeof(ICovariantIn<Base>).IsGreaterOrEqualTo(typeof(ICovariantIn<Derived>))); Contravariance interface ICovariantIn<out T> { } Trace.Assert(typeof(IContravariantIn<Derived>).IsGreaterOrEqualTo(typeof(IContravariantIn<Base>))); Invariance interface IInvariantIn<T> { } Trace.Assert(!typeof(IInvariantIn<Base>).IsGreaterOrEqualTo(typeof(IInvariantIn<Derived>)) && !typeof(IInvariantIn<Derived>).IsGreaterOrEqualTo(typeof(IInvariantIn<Base>))); Where: public static class TypeExtensions { public static bool IsGreaterOrEqualTo(this Type self, Type other) { return self.IsAssignableFrom(other); } }

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• C# 4.0: COM Interop Improvements

  - by Paulo Morgado

  Dynamic resolution as well as named and optional arguments greatly improve the experience of interoperating with COM APIs such as Office Automation Primary Interop Assemblies (PIAs). But, in order to alleviate even more COM Interop development, a few COM-specific features were also added to C# 4.0. Ommiting ref Because of a different programming model, many COM APIs contain a lot of reference parameters. These parameters are typically not meant to mutate a passed-in argument, but are simply another way of passing value parameters. Specifically for COM methods, the compiler allows to declare the method call passing the arguments by value and will automatically generate the necessary temporary variables to hold the values in order to pass them by reference and will discard their values after the call returns. From the point of view of the programmer, the arguments are being passed by value. This method call: object fileName = "Test.docx"; object missing = Missing.Value; document.SaveAs(ref fileName, ref missing, ref missing, ref missing, ref missing, ref missing, ref missing, ref missing, ref missing, ref missing, ref missing, ref missing, ref missing, ref missing, ref missing, ref missing); can now be written like this: document.SaveAs("Test.docx", Missing.Value, Missing.Value, Missing.Value, Missing.Value, Missing.Value, Missing.Value, Missing.Value, Missing.Value, Missing.Value, Missing.Value, Missing.Value, Missing.Value, Missing.Value, Missing.Value, Missing.Value); And because all parameters that are receiving the Missing.Value value have that value as its default value, the declaration of the method call can even be reduced to this: document.SaveAs("Test.docx"); Dynamic Import Many COM methods accept and return variant types, which are represented in the PIAs as object. In the vast majority of cases, a programmer calling these methods already knows the static type of a returned object form the context of the call, but has to explicitly perform a cast on the returned values to make use of that knowledge. These casts are so common that they constitute a major nuisance. To make the developer’s life easier, it is now possible to import the COM APIs in such a way that variants are instead represented using the type dynamic which means that COM signatures have now occurrences of dynamic instead of object. This means that members of a returned object can now be easily accessed or assigned into a strongly typed variable without having to cast. Instead of this code: ((Excel.Range)(excel.Cells[1, 1])).Value2 = "Hello World!"; this code can now be used: excel.Cells[1, 1] = "Hello World!"; And instead of this: Excel.Range range = (Excel.Range)(excel.Cells[1, 1]); this can be used: Excel.Range range = excel.Cells[1, 1]; Indexed And Default Properties A few COM interface features are still not available in C#. On the top of the list are indexed properties and default properties. As mentioned above, these will be possible if the COM interface is accessed dynamically, but will not be recognized by statically typed C# code. No PIAs – Type Equivalence And Type Embedding For assemblies indentified with PrimaryInteropAssemblyAttribute, the compiler will create equivalent types (interfaces, structs, enumerations and delegates) and embed them in the generated assembly. To reduce the final size of the generated assembly, only the used types and their used members will be generated and embedded. Although this makes development and deployment of applications using the COM components easier because there’s no need to deploy the PIAs, COM component developers are still required to build the PIAs.

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• C# 4.0: Covariance And Contravariance In Generics

  - by Paulo Morgado

  C# 4.0 (and .NET 4.0) introduced covariance and contravariance to generic interfaces and delegates. But what is this variance thing? According to Wikipedia, in multilinear algebra and tensor analysis, covariance and contravariance describe how the quantitative description of certain geometrical or physical entities changes when passing from one coordinate system to another.(*) But what does this have to do with C# or .NET? In type theory, a the type T is greater (>) than type S if S is a subtype (derives from) T, which means that there is a quantitative description for types in a type hierarchy. So, how does covariance and contravariance apply to C# (and .NET) generic types? In C# (and .NET), variance applies to generic type parameters and not to the resulting generic type. A generic type parameter is: covariant if the ordering of the generic types follows the ordering of the generic type parameters: Generic<T> = Generic<S> for T = S. contravariant if the ordering of the generic types is reversed from the ordering of the generic type parameters: Generic<T> = Generic<S> for T = S. invariant if neither of the above apply. If this definition is applied to arrays, we can see that arrays have always been covariant because this is valid code: object[] objectArray = new string[] { "string 1", "string 2" }; objectArray[0] = "string 3"; objectArray[1] = new object(); However, when we try to run this code, the second assignment will throw an ArrayTypeMismatchException. Although the compiler was fooled into thinking this was valid code because an object is being assigned to an element of an array of object, at run time, there is always a type check to guarantee that the runtime type of the definition of the elements of the array is greater or equal to the instance being assigned to the element. In the above example, because the runtime type of the array is array of string, the first assignment of array elements is valid because string = string and the second is invalid because string = object. This leads to the conclusion that, although arrays have always been covariant, they are not safely covariant – code that compiles is not guaranteed to run without errors. In C#, the way to define that a generic type parameter as covariant is using the out generic modifier: public interface IEnumerable<out T> { IEnumerator<T> GetEnumerator(); } public interface IEnumerator<out T> { T Current { get; } bool MoveNext(); } Notice the convenient use the pre-existing out keyword. Besides the benefit of not having to remember a new hypothetic covariant keyword, out is easier to remember because it defines that the generic type parameter can only appear in output positions — read-only properties and method return values. In a similar way, the way to define a type parameter as contravariant is using the in generic modifier: public interface IComparer<in T> { int Compare(T x, T y); } Once again, the use of the pre-existing in keyword makes it easier to remember that the generic type parameter can only be used in input positions — write-only properties and method non ref and non out parameters. Because covariance and contravariance apply only to the generic type parameters, a generic type definition can have both covariant and contravariant generic type parameters in its definition: public delegate TResult Func<in T, out TResult>(T arg); A generic type parameter that is not marked covariant (out) or contravariant (in) is invariant. All the types in the .NET Framework where variance could be applied to its generic type parameters have been modified to take advantage of this new feature. In summary, the rules for variance in C# (and .NET) are: Variance in type parameters are restricted to generic interface and generic delegate types. A generic interface or generic delegate type can have both covariant and contravariant type parameters. Variance applies only to reference types; if you specify a value type for a variant type parameter, that type parameter is invariant for the resulting constructed type. Variance does not apply to delegate combination. That is, given two delegates of types Action<Derived> and Action<Base>, you cannot combine the second delegate with the first although the result would be type safe. Variance allows the second delegate to be assigned to a variable of type Action<Derived>, but delegates can combine only if their types match exactly. If you want to learn more about variance in C# (and .NET), you can always read: Covariance and Contravariance in Generics — MSDN Library Exact rules for variance validity — Eric Lippert Events get a little overhaul in C# 4, Afterward: Effective Events — Chris Burrows Note: Because variance is a feature of .NET 4.0 and not only of C# 4.0, all this also applies to Visual Basic 10.

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• LINQ: Enhancing Distinct With The PredicateEqualityComparer

  - by Paulo Morgado

  Today I was writing a LINQ query and I needed to select distinct values based on a comparison criteria. Fortunately, LINQ’s Distinct method allows an equality comparer to be supplied, but, unfortunately, sometimes, this means having to write custom equality comparer. Because I was going to need more than one equality comparer for this set of tools I was building, I decided to build a generic equality comparer that would just take a custom predicate. Something like this: public class PredicateEqualityComparer<T> : EqualityComparer<T> { private Func<T, T, bool> predicate; public PredicateEqualityComparer(Func<T, T, bool> predicate) : base() { this.predicate = predicate; } public override bool Equals(T x, T y) { if (x != null) { return ((y != null) && this.predicate(x, y)); } if (y != null) { return false; } return true; } public override int GetHashCode(T obj) { if (obj == null) { return 0; } return obj.GetHashCode(); } } Now I can write code like this: .Distinct(new PredicateEqualityComparer<Item>((x, y) => x.Field == y.Field)) But I felt that I’d lost all conciseness and expressiveness of LINQ and it doesn’t support anonymous types. So I came up with another Distinct extension method: public static IEnumerable<TSource> Distinct<TSource>(this IEnumerable<TSource> source, Func<TSource, TSource, bool> predicate) { return source.Distinct(new PredicateEqualityComparer<TSource>(predicate)); } And the query is now written like this: .Distinct((x, y) => x.Field == y.Field) Looks a lot better, doesn’t it?

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• JavaOne Call for Papers

  - by Paulo Folgado

  Hot off the presses!Yes, there will be a JavaOne Conference in 2010. JavaOne will be located with Oracle Develop during Oracle OpenWorld in San Francisco. Unlike in recent years, JavaOne will focus solely on Java Technology and its associated ecosystem and will also include a Sun partner showcase. All Java users and partners are invited to submit papers. The JavaOne Call for Papers is now open.Please click here to learn more.

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• Reminder: Benefícios da Virtualização para ISVs - 14/Dez/10, Porto

  - by Paulo Folgado

  Esta formação aborda as principais dificuldades com que os Independent Software Vendors (ISVs) se confrontam quando têm de escolher as plataformas sobre as quais irão certificar, instalar e suportar as suas aplicações, e como o Oracle VM (e o Oracle Enterprise Linux) os podem ajudar a ultrapassar essas dificuldades. O modelo de negócio clássico de um ISV - desenvolver uma solução aplicacional para resolver um determinado problema de negócio, analizar o mercado para determinar quais os sistemas operativos e o hardware que os clientes do seu mercado alvo usam, e decidir suportar as plataformas hardware e software que 80% dos seus clientes do seu mercado alvo usam (e tratar como excepções outras configurações que lhe sejam solicitadas por alguns clientes importantes) - funcionou bem no anos 80 e princípios dos anos 90, quando havia uma menor diversidade de plataformas. Contudo, com o aparecimentos nos últimos anos de múltiplas versões de sistemas operativos e de "sabores" Linux, este modelo começou a tornar-se um pesadelo. Cada cliente tem a sua plataforma de eleição e espera dos ISV que suportem essas suas opções, o que constitui um sorvedouro dos recursos e dos custos dos ISVs. As tecnologias de virtualização da Oracle, ao permitirem "simular" uma determinada configuração de hardware, fazendo com que o sistema operativo "pense" que está correr numa configuração de hardware pré-definida e normalizada, na qual correm as aplicações, constituem um veículo excelente para os ISVs que procuram uma solução simples, fácil de instalar e fácil de suportar para instalação das suas aplicações, permitindo obter grandes economias de custos em termos de desenvolvimento, teste e suporte dessas aplicações. Quem deve assistir? Esta formação dirige-se sobretudo a quem que tomar decisões sobre as plataformas tecnológicas que o ISV tem de suportar, assim como a quem lida com a estrutura de custos da suas operações, com uma visão dos custos associados ao desenvolvimento, certificação, instalação e suporte de múltiplas plataformas. Se quer saber mais sobre o Oracle VM e como ele pode ajudar a reduzir drasticamente os sues custos, não perca esta formação. AGENDA: 09:00 Welcome & Introduction  ISV Partner View... Why Use Virtualization?   The ISV Deployment Dilemma: The Problem of Supporting Multiple Platforms  How can Virtualization Help?  The use of Templates What is a Template?  How are Templates Created?  Customer's Point of View  Assembly Builder  Weblogic Virtual Edition Managing Oracle VM Best Practices for Virtualizing Oracle Database 11g  Managing Virtual Environments  Coffee Break   Oracle Complete and Integrated Virtualization Portfolio From Datacenter to Desktop  The Next Generation Virtualization  Private Cloud with Middleware Virtualization  Benefits of Using Oracle VM (and Oracle Enterprise Linux) Support Advantages  Production Ready Virtual Machines  Licensing Terms  Partner Resources and OPN Benefits  12:45 Q&A and Wrap-up  Data: 14 de Dezembro - 09h00 / 13h00Local: Oracle Portugal, Av. da Boavista, 1837- Edifício Burgo - Escritório 13.4, 4100-133 PORTO Audiência: Responsáveis de Desenvolvimento, de Tecnologia e Serviços dos parceiros ISV da Oracle Formação realizada pela Altimate

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• TechDays 2010: What’s New On C# 4.0

  - by Paulo Morgado

  I would like to thank those that attended my session at TechDays 2010 and I hope that I was able to pass the message of what’s new on C#. For those that didn’t attend (or did and want to review it), the presentation can be downloaded from here. Code samples can be downlaoded from here. Here’s a list of resources mentioned on the session: The evolution of C# The Evolution Of C# Covariance and contravariance  C# 4.0: Covariance And Contravariance In Generics Covariance And Contravariance In Generics Made Easy Covarince and Contravariance in Generics Exact rules for variance validity Events get a little overhaul in C# 4, Afterward: Effective Events Named and optional arguments  Named And Optional Arguments Alternative To Optional Arguments Named and Optional Arguments (C# Programming Guide) Dynamic programming  Dynamic Programming C# Proposal: Compile Time Static Checking Of Dynamic Objects Using Type dynamic (C# Programming Guide) Dynamic Language Runtime Overview COM Interop Improvements COM Interop Improvements Type Equivalence and Embedded Interop Types Conclusion Visual C# Developer Center Visual C# 2010 Samples C# Language Specification 4.0 .NET Reflector LINQPad

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• Top Partners 2010 Specialization Awards

  - by Paulo Folgado

  Portugal Top Partners 2010 Specialization Awards Be Recognized Caro Parceiro, Vão ter lugar mais uma vez os prémios Top Partners, que anualmente visam reconhecer as realizações dos parceiros Oracle em termos de negócio. Este ano, sob o signo de Partner Specialization Awards, pretendemos, a par com os resultados de negócio, premiar igualmente o esforço dos nossos parceiros em termos de especialização e de desenvolvimento da sua auto-suficiência. Outras das inovações deste ano é o processo ser baseado numa entrega de candidaturas dos parceiros, e de estas serem avaliadas, com base em critérios definidos, por um júri incluindo entidades externas. Categorias dos Prémios: ·       Database Partner of the Year ·       Middleware Partner of the Year ·       Applications Partner of the Year ·       ISV Partner of the Year ·       Midsize Partner of the Year ·       Industry Partner of the Year ·       Accelerate Partner of the Year   Um dos objectivos dos Top Partners 2010 Specialization Awards é destacar e incentivar a cooperação entre a Oracle e os seus parceiros. Por esta razão, para além dos vários critérios específicos, os parceiros têm de cumprir um conjunto de critérios gerais: ·       Cooperação com a Oracle ·       Investimento no desenvolvimento dos conhecimentos em Oracle ·       Aproximação conjunta ao mercado ·       Utilização activa dos recursos e ferramentas do Oracle PartnerNetwork através do Portal OPN   Os Top Partners 2010 Specialization Awards estão abertos a todos os parceiros em Portugal que estejam registados no OPN Specialized em uma ou mais especializações. As candidaturas podem ser enviadas até 31 de Maio de 2010. Be recognized! Para mais informação clique aqui

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• FGLRX does not have /usr/lib/libGL.so lib

  - by Paulo Lopes

  I am trying to compile some OpenGL apps from sources but there is no /usr/lib/libGL.so, or /usr/lib/libGL.so.1 or even /usr/lib/libGL.so.1.2. However fglrxinfo says: display: :0.0 screen: 0 OpenGL vendor string: ATI Technologies Inc. OpenGL renderer string: ATI Mobility Radeon HD 4500 Series OpenGL version string: 3.3.10237 Compatibility Profile Context Which is what i espect and the gears demo also works... How do i get those files? I tried the MESA files and then i got SW rendering which is not what i want...

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• Oracle VM VirtualBox 4.0 Now Available

  - by Paulo Folgado

  Delivering on Oracle's commitment to open source, Oracle VM VirtualBox 4.0 is now available, further enhancing the popular, open source, cross-platform virtualization software.   "Oracle VM VirtualBox 4.0 is the third major product release in just over a year, and adds to the many new product releases across the Oracle Virtualization product line, illustrating the investment and importance that Oracle places on providing a comprehensive desktop to datacenter virtualization solution," says Wim Coekaerts, senior vice president, Linux and Virtualization Engineering, Oracle. "With an improved user interface and added virtual hardware support, customers will find Oracle VM VirtualBox 4.0 provides a richer user experience." Part of Oracle's comprehensive portfolio of virtualization solutions, Oracle VM VirtualBox enables desktop or laptop computers to run multiple guest operating systems simultaneously, allowing users to get the most flexibility and utilization out of their PCs, and supports a variety of host operating systems, including Windows, Mac OS X, most popular flavors of Linux (including Oracle Linux), and Oracle Solaris. Oracle VM VirtualBox 4.0 delivers increased capacity and throughput to handle greater workloads, enhanced virtual appliance capabilities, and significant usability improvements. Support for the latest in virtual hardware, including chipsets supporting PCI Express, further extends the value delivered to customers, partners, and developers. Highlights of Oracle VM VirtualBox 4.0 include New Open Architecture - Oracle and community developers can now create extensions that customize Oracle VM VirtualBox and add features not previously available.Enhanced Usability - A new scalable display mode enables users to view more virtual displays on their existing monitors. Improvements to VM management, including visual VM previews, an optional attributes display, and easy launch shortcut creation enables administrators and power users to customize the interface to make it as simple or as comprehensive as required.Increased Capacity and Throughput - A new asynchronous I/O model for networked (iSCSI) and local storage delivers significant storage related performance improvements, while new optimizations allow larger datacenter-class workloads, such as Oracle's middeware, to be run on 32-bit Windows hosts for testing and demo purposes. Powerful Virtual Appliance Sharing Capabilities - Enhanced support for standards-compliant OVF appliances and added support for OVA format descriptors. All information about a VM may be stored in a single folder to facilitate easier direct sharing among VMs. Support for Latest Virtual Hardware - A new, modern virtual chipset supporting PCI Express and other hardware enhancements including high-definition audio devices helps ensure support for the most demanding virtual workloads.

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• Oracle buys Secerno

  - by Paulo Folgado

  Adds Heterogeneous Database Firewall to Oracle's Industry-leading Database Security SolutionsRedwood Shores, CA - May 20, 2010News FactsOracle has agreed to acquire Secerno, a provider of database firewall solutions for Oracle and non-Oracle databases.Organizations require a comprehensive security solution which includes database firewall functionality to prevent sophisticated attacks from reaching databases.Secerno's solution adds a critical defensive layer of security around databases, which blocks unauthorized activity in real-time.Secerno's products are expected to augment Oracle's industry-leading portfolio of database security solutions, including Oracle Advanced Security, Oracle Database Vault and Oracle Audit Vault to further ensure data privacy, protect against threats, and enable regulatory compliance.The combination of Oracle and Secerno underscores Oracle's commitment to provide customers with the most comprehensive and advanced security offering that helps reduce the costs and complexity of securing their information throughout the enterprise.The transaction is expected to close before end of June 2010. Financial details of the transaction were not disclosed.Supporting Quote:"The Secerno acquisition is in direct response to increasing customer challenges around mitigating database security risk," said Andrew Mendelsohn, senior vice president, Oracle Database Server Technologies. "Secerno's database firewall product acts as a first line of defense against external threats and unauthorized internal access with a protective perimeter around Oracle and non-Oracle databases. Together, Oracle's complete set of database security solutions and Secerno's technology will provide customers with the ability to safeguard their critical business information.""As a provider of database firewall solutions that help customers safeguard their enterprise databases, Secerno is a natural addition to Oracle's industry-leading database security solutions," said Steve Hurn, CEO Secerno. "Secerno has been providing enterprises and their IT Security departments strong assurance that their databases are protected from attacks and breaches. We are excited to bring Secerno's domain expertise to Oracle, and ensure continuity and success for our current customers, partners and prospects."Support Resources:About Oracle and SecernoGeneral PresentationFAQCustomer LetterPartner Letter

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• LINQ: Single vs. SingleOrDefault

  - by Paulo Morgado

  Like all other LINQ API methods that extract a scalar value from a sequence, Single has a companion SingleOrDefault. The documentation of SingleOrDefault states that it returns a single, specific element of a sequence of values, or a default value if no such element is found, although, in my opinion, it should state that it returns a single, specific element of a sequence of values, or a default value if no such element is found. Nevertheless, what this method does is return the default value of the source type if the sequence is empty or, like Single, throws an exception if the sequence has more than one element. I received several comments to my last post saying that SingleOrDefault could be used to avoid an exception. Well, it only “solves” half of the “problem”. If the sequence has more than one element, an exception will be thrown anyway. In the end, it all comes down to semantics and intent. If it is expected that the sequence may have none or one element, than SingleOrDefault should be used. If it’s not expect that the sequence is empty and the sequence is empty, than it’s an exceptional situation and an exception should be thrown right there. And, in that case, why not use Single instead? In my opinion, when a failure occurs, it’s best to fail fast and early than slow and late. Other methods in the LINQ API that use the same companion pattern are: ElementAt/ElementAtOrDefault, First/FirstOrDefault and Last/LastOrDefault.

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• Oracle + Sun Product Strategy Webcast Series

  - by Paulo Folgado

  The Oracle + Sun Product Strategy Webcast series is composed of informative, on-demand sessions that offer strategies for Sun's major product lines related to the company combination, explain how Oracle will deliver more innovation to our customers, and outline our approach to protecting customers' investments. Ranging from 5 to 27 minutes each, the Webcasts cover the strategies for hardware, systems, software, solutions, and partners.In addition, Judson Althoff, SVP, Worldwide Alliances and Channels, Oracle, followed up the Webcast series with a video FAQ to help answer the following top partner questions about the Oracle + Sun combination and the OPN Specialized program: What is the impact the overall combined company will have on the partners?What are Oracle's plans for selling direct and what is the impact to partners?How will Sun partners integrate into OPN Specialized?As a Sun partner, am I automatically migrated into OPN Specialized?Will Oracle continue to partner with other hardware vendors?How will Oracle map existing Sun investments and certifications into OPN Specialized?As a Sun partner new to Oracle, where should I be placing my focus?What can partners expect to see relative to Exadata V2?How do content delivery platforms (CDPs) fit into the Oracle framework?How do existing Sun Partners place orders?

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• Atenção: Oracle Embedded - 14/Abr/10 (é já esta semana!)

  - by Paulo Folgado

  Atenção, é já esta semana, na próxima 4ª feira dia 14/Abr, que terá lugar o evento dedicado a soluções para sistemas Embedded. A Oracle oferece hoje a gama mais completa do mercado em tecnologias embedded, tanto para ISVs como para fabricantes de dispositivos e equipamentos, proporcionando-lhe a escolha dos produtos de base de dados e middleware embeddable que melhor se ajustem aos seus requisitos técnicos.Segundo a IDC, a Oracle é hoje o líder mundial no mercado das bases de dados embedded com uma quota de mercado de 28,2% em 2008, estando a crescer a um ritmo muito superior ao seu concorrente mais próximo e à media do mercado.Clique aqui para saber mais sobre este evento.

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