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  • Oracle on Oracle: How Oracle IT uses Oracle IDM

    - by Darin Pendergraft
    Sometimes, the toughest customers are your own employees.  Chirag Andani runs the Product Development Security IT Group - which means that his group is responsible for internal Identity Management and Security inside Oracle. Like a lot of large, global companies, Oracle has a complicated and dynamic IT infrastructure which continues to change as the company grows and acquires companies. I caught up with Chirag and asked him what kinds of problems his team faces, and asked him what he thinks about Oracle IDM, and 11gR2 in particular.Listen to the podcast interview here: podcast link

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  • C#/.NET Little Pitfalls: The Dangers of Casting Boxed Values

    - by James Michael Hare
    Starting a new series to parallel the Little Wonders series.  In this series, I will examine some of the small pitfalls that can occasionally trip up developers. Introduction: Of Casts and Conversions What happens when we try to assign from an int and a double and vice-versa? 1: double pi = 3.14; 2: int theAnswer = 42; 3:  4: // implicit widening conversion, compiles! 5: double doubleAnswer = theAnswer; 6:  7: // implicit narrowing conversion, compiler error! 8: int intPi = pi; As you can see from the comments above, a conversion from a value type where there is no potential data loss is can be done with an implicit conversion.  However, when converting from one value type to another may result in a loss of data, you must make the conversion explicit so the compiler knows you accept this risk.  That is why the conversion from double to int will not compile with an implicit conversion, we can make the conversion explicit by adding a cast: 1: // explicit narrowing conversion using a cast, compiler 2: // succeeds, but results may have data loss: 3: int intPi = (int)pi; So for value types, the conversions (implicit and explicit) both convert the original value to a new value of the given type.  With widening and narrowing references, however, this is not the case.  Converting reference types is a bit different from converting value types.  First of all when you perform a widening or narrowing you don’t really convert the instance of the object, you just convert the reference itself to the wider or narrower reference type, but both the original and new reference type both refer back to the same object. Secondly, widening and narrowing for reference types refers the going down and up the class hierarchy instead of referring to precision as in value types.  That is, a narrowing conversion for a reference type means you are going down the class hierarchy (for example from Shape to Square) whereas a widening conversion means you are going up the class hierarchy (from Square to Shape).  1: var square = new Square(); 2:  3: // implicitly convers because all squares are shapes 4: // (that is, all subclasses can be referenced by a superclass reference) 5: Shape myShape = square; 6:  7: // implicit conversion not possible, not all shapes are squares! 8: // (that is, not all superclasses can be referenced by a subclass reference) 9: Square mySquare = (Square) myShape; So we had to cast the Shape back to Square because at that point the compiler has no way of knowing until runtime whether the Shape in question is truly a Square.  But, because the compiler knows that it’s possible for a Shape to be a Square, it will compile.  However, if the object referenced by myShape is not truly a Square at runtime, you will get an invalid cast exception. Of course, there are other forms of conversions as well such as user-specified conversions and helper class conversions which are beyond the scope of this post.  The main thing we want to focus on is this seemingly innocuous casting method of widening and narrowing conversions that we come to depend on every day and, in some cases, can bite us if we don’t fully understand what is going on!  The Pitfall: Conversions on Boxed Value Types Can Fail What if you saw the following code and – knowing nothing else – you were asked if it was legal or not, what would you think: 1: // assuming x is defined above this and this 2: // assignment is syntactically legal. 3: x = 3.14; 4:  5: // convert 3.14 to int. 6: int truncated = (int)x; You may think that since x is obviously a double (can’t be a float) because 3.14 is a double literal, but this is inaccurate.  Our x could also be dynamic and this would work as well, or there could be user-defined conversions in play.  But there is another, even simpler option that can often bite us: what if x is object? 1: object x; 2:  3: x = 3.14; 4:  5: int truncated = (int) x; On the surface, this seems fine.  We have a double and we place it into an object which can be done implicitly through boxing (no cast) because all types inherit from object.  Then we cast it to int.  This theoretically should be possible because we know we can explicitly convert a double to an int through a conversion process which involves truncation. But here’s the pitfall: when casting an object to another type, we are casting a reference type, not a value type!  This means that it will attempt to see at runtime if the value boxed and referred to by x is of type int or derived from type int.  Since it obviously isn’t (it’s a double after all) we get an invalid cast exception! Now, you may say this looks awfully contrived, but in truth we can run into this a lot if we’re not careful.  Consider using an IDataReader to read from a database, and then attempting to select a result row of a particular column type: 1: using (var connection = new SqlConnection("some connection string")) 2: using (var command = new SqlCommand("select * from employee", connection)) 3: using (var reader = command.ExecuteReader()) 4: { 5: while (reader.Read()) 6: { 7: // if the salary is not an int32 in the SQL database, this is an error! 8: // doesn't matter if short, long, double, float, reader [] returns object! 9: total += (int) reader["annual_salary"]; 10: } 11: } Notice that since the reader indexer returns object, if we attempt to convert using a cast to a type, we have to make darn sure we use the true, actual type or this will fail!  If the SQL database column is a double, float, short, etc this will fail at runtime with an invalid cast exception because it attempts to convert the object reference! So, how do you get around this?  There are two ways, you could first cast the object to its actual type (double), and then do a narrowing cast to on the value to int.  Or you could use a helper class like Convert which analyzes the actual run-time type and will perform a conversion as long as the type implements IConvertible. 1: object x; 2:  3: x = 3.14; 4:  5: // if you want to cast, must cast out of object to double, then 6: // cast convert. 7: int truncated = (int)(double) x; 8:  9: // or you can call a helper class like Convert which examines runtime 10: // type of the value being converted 11: int anotherTruncated = Convert.ToInt32(x); Summary You should always be careful when performing a conversion cast from values boxed in object that you are actually casting to the true type (or a sub-type). Since casting from object is a widening of the reference, be careful that you either know the exact, explicit type you expect to be held in the object, or instead avoid the cast and use a helper class to perform a safe conversion to the type you desire. Technorati Tags: C#,.NET,Pitfalls,Little Pitfalls,BlackRabbitCoder

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  • Debian Squeeze Pre-review

    <b>Christofoo Review: </b>"Right now, Lenny (5.0) is the stable release, and Squeeze (6.0) is in testing. Sometime "soon" Squeeze will get frozen, which means the regular flow of package migration will stop, and from then on it will only get bug and security fixes through a method of back-porting."

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  • Cartoon Games and Arcade Games SEO Part 2

    Now students, today we will be talking about SEO. But not just some regular, plain, old SEO. I'm talking arcades here, and that means we gotta put a little spin on it and change things up just a bit. Isn't that exciting! Learning new techniques are great, so let's start.

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  • Get your Master Immersion learning on!

    - by AaronBertrand
    Time is running out to register for the Master Immersion training events being held in Dallas, TX by SQLskills . These particular events will be instructed by Paul Randal ( blog | twitter ), Kimberly Tripp ( blog | twitter ), and Brent Ozar ( blog | twitter ) and reflect the new format for the Microsoft Certified Master (MCM) program. This means training in the low 4 figures instead of close to $20K, and that you can take at your own pace. We at SQL Sentry ( twitter ) are quite proud to be the exclusive...(read more)

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  • Remove page flicker in IE8

    - by webbes
    In this pet project of mine I have two large background images. Unfortunately this means that IE will display a nasty page flicker on each request. Implementing AJAX for getting rid of it, is overkill. I solved this in a different way....(read more)

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  • Get your Master Immersion learning on!

    - by AaronBertrand
    Time is running out to register for the Master Immersion training events being held in Dallas, TX by SQLskills . These particular events will be instructed by Paul Randal ( blog | twitter ), Kimberly Tripp ( blog | twitter ), and Brent Ozar ( blog | twitter ) and reflect the new format for the Microsoft Certified Master (MCM) program. This means training in the low 4 figures instead of close to $20K, and that you can take at your own pace. We at SQL Sentry ( twitter ) are quite proud to be the exclusive...(read more)

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  • SQL SERVER – PREEMPTIVE and Non-PREEMPTIVE – Wait Type – Day 19 of 28

    - by pinaldave
    In this blog post, we are going to talk about a very interesting subject. I often get questions related to SQL Server 2008 Book-Online about various Preemptive wait types. I got a few questions asking what these wait types are and how they could be interpreted. To get current wait types of the system, you can read this article and run the script: SQL SERVER – DMV – sys.dm_os_waiting_tasks and sys.dm_exec_requests – Wait Type – Day 4 of 28. Before we continue understanding them, let us study first what PREEMPTIVE and Non-PREEMPTIVE waits in SQL Server mean. PREEMPTIVE: Simply put, this wait means non-cooperative. While SQL Server is executing a task, the Operating System (OS) interrupts it. This leads to SQL Server to involuntarily give up the execution for other higher priority tasks. This is not good for SQL Server as it is a particular external process which makes SQL Server to yield. This kind of wait can reduce the performance drastically and needs to be investigated properly. Non-PREEMPTIVE: In simple terms, this wait means cooperative. SQL Server manages the scheduling of the threads. When SQL Server manages the scheduling instead of the OS, it makes sure its own priority. In this case, SQL Server decides the priority and one thread yields to another thread voluntarily. In the earlier version of SQL Server, there was no preemptive wait types mentioned and the associated task status with them was marked as suspended. In SQL Server 2005, preemptive wait types were not listed as well, but their associated task status was marked as running. In SQL Server 2008, preemptive wait types are properly listed and their associated task status is also marked as running. Now, SQL Server is in Non-Preemptive mode by default and it works fine. When CLR, extended Stored Procedures and other external components run, they run in Preemptive mode, leading to the creation of these wait types. There are a wide variety of preemptive wait types. If you see consistent high value in the Preemptive wait types, I strongly suggest that you look into the wait type and try to know the root cause. If you are still not sure, you can send me an email or leave a comment about it and I will do my best to help you reduce this wait type. Read all the post in the Wait Types and Queue series. Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: Pinal Dave, PostADay, SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, SQL Wait Stats, SQL Wait Types, T SQL, Technology

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  • Week in Geek: Dropbox to Shut Down ‘Public Folders’ Feature in August

    - by Asian Angel
    This week’s edition of WIG is filled with news link goodness covering topics such as new details and screenshots of Windows 8, the existence of a Google tablet has been confirmed, an Australian online retailer has introduced a special tax on IE 7 users, and more. Chainlink fence clipart courtesy of For Web Designer. HTG Explains: What Is Windows RT and What Does It Mean To Me? HTG Explains: How Windows 8′s Secure Boot Feature Works & What It Means for Linux Hack Your Kindle for Easy Font Customization

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  • Friday Fun: Snail Bob 2

    - by Asian Angel
    Everyone’s favorite day of the week is here once again and that means it is time for some fun! In this week’s game your job is to help Snail Bob travel safely through a dangerous forest and reach his Grandpa’s house in one piece.What is a Histogram, and How Can I Use it to Improve My Photos?How To Easily Access Your Home Network From Anywhere With DDNSHow To Recover After Your Email Password Is Compromised

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  • Survey of MySQL Storage Engines

    <b>Database Journal:</b> "MySQL has an interesting architecture that sets it apart from some other enterprise database systems. It allows you to plug in different modules to handle storage. What that means to end users is that it is quite flexible, offering an interesting array of different storage engines with different features, strengths, and tradeoffs."

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  • The APEX of Business Value...or...the Business Value of APEX? Oracle Cloud Takes Oracle APEX to New Heights!

    - by Gene Eun
    The attraction of Oracle Application Express (APEX) has increased tremendously with the recent launch of the Oracle Cloud. APEX already supported departmental development and deployment of business applications with minimal involvement from the IT department. Positioned as the ideal replacement for MS Access, APEX probably has managed better to capture the eye of developers and was used for enterprise application development at least as much as for the kind of tactical applications that Oracle strategically positioned it for. With APEX as PaaS from the Oracle Cloud, a leap is made to a much higher level of business value. Now the IT department is not even needed to make infrastructure available with a database running  on it. All the business needs is a credit card. And the business application that is developed, managed and used from the cloud through a standard browser can now just as easily be accessed by users from around the world as by users from the business department itself. As a bonus – the development of the APEX application is also done in the cloud – with no special demands on the location or the enterprise access privileges of the developers. To sum it up: APEX from Oracle Cloud Database Service get the development environment up and running in minutes no involvement from the internal IT department required (not for infrastructure, platform, or development) superior availability and scalability is offered by Oracle users from anywhere in the world can be invited to access the application developers from anywhere in the world can participate in creating and maintaining the application In addition: because the Oracle Cloud platform is the same as the on-premise platform, you can still decide to move the APEX application between the cloud and the local environment – and back again. The REST-ful services that are available through APEX allow programmatic interaction with the database under the APEX application. That means that this database can be synchronized with on premise databases or data stores in (other) clouds. Through the Oracle Cloud Messaging Service, the APEX application can easily enter into asynchronous conversations with other APEX applications, Fusion Middleware applications (ADF, SOA, BPM) and any other type of REST-enabled application. In my opinion, now, for the first time perhaps, APEX offers the attraction to the business that has been suggested before: because of the cloud, all the business needs is  a credit card (a budget of $175 per month), an internet-connection and a browser. Not like before, with a PC hidden under a desk or a database running somewhere in the data center. No matter how unattended: equipment is needed, power is consumed, the database needs to be kept running and if Oracle Database XE does not suffice, software licenses are required as well. And this set up always has a security challenge associated with it. The cloud fee for the Oracle Cloud Database Service includes infrastructure, power, licenses, availability, platform upgrades, a collection of reusable application components and the development and runtime environments containing the APEX platform. Of course this not only means that business departments can move quickly without having to convince their IT colleagues to move along – it also means that small organizations that do not even have IT colleagues can do the same. Getting tailored applications or applications up and running to get in touch with users and customers all over the world is now within easy reach for small outfits – without any investment. My misunderstanding For a long time, I was under the impression that the essence of APEX was that the business could create applications themselves – meaning that business ‘people’ would actually go into APEX to create the application. To me APEX was too much of a developers’ tool to see that happen – apart from the odd business analyst who missed his or her calling as an IT developer. Having looked at various other cloud based development offerings – including Force.com, Mendix, WaveMaker, WorkXpress, OrangeScape, Caspio and Cordys- I have come to realize my mistake. All these platforms are positioned for 'the business' but require a fair amount of coding and technical expertise. However, they make the business happy nevertheless, because they allow the  business to completely circumvent the IT department. That is the essence. Not having to go through the red tape, not having to wait for IT staff who (justifiably) need weeks or months to provide an environment, not having to deal with administrators (again, justifiably) refusing to take on that 'strange environment'. Being able to think of an initiative and turn into action right away. The business does not have to build the application - it can easily hire some external developers or even that nerdy boy next door. They can get started, get an application up and running and invite users in – especially external users such as customers. They will worry later about upgrades and life cycle management and integration. To get applications up and running quickly and start turning ideas into action and results rightaway. That is the key selling point for all these cloud offerings, including APEX from the Cloud. And it is a compelling story. For APEX probably even more so than for the others. While I consider APEX a somewhat proprietary framework compared with ‘regular’ Java/JEE web development (or even .NET and PHP  development), it is still far more open than most cloud environments. APEX is SQL and PL/SQL based – nothing special about those languages – and can run just as easily on site as in the cloud. It has been around since 2004 (that is not including several predecessors that fed straight into APEX) so it can be considered pretty mature. Oracle as a company seems pretty stable – so investments in its technology are bound to last for some time to come. By the way: neither APEX nor the other Cloud DevaaS offerings are targeted at creating applications with enormous life times. They fit into a trend of agile development and rapid life cycle management, with fairly light weight user interfaces that quickly adapt to taste, technology trends and functional requirements and that are easily replaced. APEX and ADF – a match made in heaven?! (or at least in the sky) Note that using APEX only for cloud based database with REST-ful Services is also a perfectly viable scenario: any UI – mobile or browser based – capable of consuming REST-ful services can be created against such a business tier. Creating an ADF Mobile application for example that runs aginst REST-ful services is a best practice for mobile development. Such REST-ful services can be consumed from any service provider – including the Cloud based APEX powered REST-ful services running against the Oracle Cloud Database Service! The ADF Mobile architecture overview can easily be morphed to fit the APEX services in – allowing for a cloud based mobile app: Want to learn more about Oracle Database Cloud Service or Oracle Cloud, just visit cloud.oracle.com  or oracle.com/cloud. Repost of a blog entry by Rick Greenwald, Director of Product Management, Oracle Database Cloud Service.

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  • Exceptional DBA Awards 2011

    - by Rebecca Amos
    From today, we’re accepting nominations for the 2011 Exceptional DBA Awards. DBAs make a vital contribution to the running of the companies they work for, and the Exceptional DBA Awards aim to acknowledge this and make this contribution more widely known. Check out our new website for all the info: www.exceptionaldba.com  Being an exceptional DBA doesn’t mean you have to sleep at the office, or know everything there is to know about SQL Server; who ever could? It means that you make an effort to make your servers secure and reliable, and to make your users’ lives easier. Maybe you’ve helped a junior colleague learn something new about server backups? Or cancelled your coffee break to get a database back online? Or contributed to a forum post on performance monitoring? All of these actions show that you might be an exceptional DBA. So have a think about the tasks you do every day that already make you exceptional – and then get started on your entry! You just need to answer a few questions on our website about your experience as a DBA, some of your biggest achievements, and any other activities you participate in within the SQL Server community. Anyone who is currently working as a SQL Server database administrator can enter, or be nominated by someone else. We’ve got four fantastic judges for the Awards, who you’ll be familiar with already: Brent Ozar, Brad McGehee, Rodney Landrum and Steve Jones. They’ll pick five finalists, and then we’ll ask the SQL Server community to vote for their winner. Not only could you win the respect and recognition of peers and colleagues, but the prizes also include full conference registration for the 2011 PASS Summit in Seattle (where the awards ceremony will take place), four nights' hotel accommodation, and $300 towards travel expenses. The winner will get a copy of Red Gate’s SQL DBA Bundle – and they’ll also be featured here, on Simple-Talk. So what are you waiting for? Chances are you’ve already made a small effort for someone today that means you might be an exceptional DBA. Visit the website now, and start writing your entry – or nominate your favourite DBA to enter: www.exceptionaldba.com

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  • QotD: Matt Stephens on OpenJDK in 2012 at the Register

    - by $utils.escapeXML($entry.author)
    While Java SE churns and gets pushed back, the new initiatives do at least show OpenJDK is reinvigorating the Java space. The project has picked up speed just a little too late for the fifth anniversary of the open-sourcing of Java, but if these promised developments really do come together then that means next year should see a series of “one last things” missing from 2011.Matt Stephens in an article in the Register.

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  • Website Health Check - Keyword Blunders - Part 2

    Website Health Check is becoming an integral part of Search Engine Optimization (SEO). The reason is that it helps to find mistakes in websites that are commonly unnoticed. Eventually, it means the difference between coming up as the first or last result in a search engine query. A small part regarding keywords, such as keyword density, keyword stuffing, spelling errors, cloaking, etc., is explained here.

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  • Azure, don't give me multiple VMs, give me one elastic VM

    - by FransBouma
    Yesterday, Microsoft revealed new major features for Windows Azure (see ScottGu's post). It all looks shiny and great, but after reading most of the material describing the new features, I still find the overall idea behind all of it flawed: why should I care on how much VMs my web app runs? Isn't that a problem to solve for the Windows Azure engineers / software? And what if I need the file system, why can't I simply get a virtual filesystem ? To illustrate my point, let's use a real example: a product website with a customer system/database and next to it a support site with accompanying database. Both are written in .NET, using ASP.NET and use a SQL Server database each. The product website offers files to download by customers, very simple. You have a couple of options to host these websites: Buy a server, place it in a rack at an ISP and run the sites on that server Use 'shared hosting' with an ISP, which means your sites' appdomains are running on the same machine, as well as the files stored, and the databases are hosted in the same server as the other shared databases. Hire a VM, install your OS of choice at an ISP, and host the sites on that VM, basically the same as the first option, except you don't have a physical server At some cloud-vendor, either host the sites 'shared' or in a VM. See above. With all of those options, scalability is a problem, even the cloud-based ones, though not due to the same reasons: The physical server solution has the obvious problem that if you need more power, you need to buy a bigger server or more servers which requires you to add replication and other overhead Shared hosting solutions are almost always capped on memory usage / traffic and database size: if your sites get too big, you have to move out of the shared hosting environment and start over with one of the other solutions The VM solution, be it a VM at an ISP or 'in the cloud' at e.g. Windows Azure or Amazon, in theory allows scaling out by simply instantiating more VMs, however that too introduces the same overhead problems as with the physical servers: suddenly more than 1 instance runs your sites. If a cloud vendor offers its services in the form of VMs, you won't gain much over having a VM at some ISP: the main problems you have to work around are still there: when you spin up more than one VM, your application must be completely stateless at any moment, including the DB sub system, because what's in memory in instance 1 might not be in memory in instance 2. This might sounds trivial but it's not. A lot of the websites out there started rather small: they were perfectly runnable on a single machine with normal memory and CPU power. After all, you don't need a big machine to run a website with even thousands of users a day. Moving these sites to a multi-VM environment will cause a problem: all the in-memory state they use, all the multi-page transitions they use while keeping state across the transition, they can't do that anymore like they did that on a single machine: state is something of the past, you have to store every byte of state in either a DB or in a viewstate or in a cookie somewhere so with the next request, all state information is available through the request, as nothing is kept in-memory. Our example uses a bunch of files in a file system. Using multiple VMs will require that these files move to a cloud storage system which is mounted in each VM so we don't have to store the files on each VM. This might require different file paths, but this change should be minor. What's perhaps less minor is the maintenance procedure in place on the new type of cloud storage used: instead of ftp-ing into a VM, you might have to update the files using different ways / tools. All in all this makes moving an existing website which was written for an environment that's based around a VM (namely .NET with its CLR) overly cumbersome and problematic: it forces you to refactor your website system to be able to be used 'in the cloud', which is caused by the limited way how e.g. Windows Azure offers its cloud services: in blocks of VMs. Offer a scalable, flexible VM which extends with my needs Instead, cloud vendors should offer simply one VM to me. On that VM I run the websites, store my DB and my files. As it's a virtual machine, how this machine is actually ran on physical hardware (e.g. partitioned), I don't care, as that's the problem for the cloud vendor to solve. If I need more resources, e.g. I have more traffic to my server, way more visitors per day, the VM stretches, like I bought a bigger box. This frees me from the problem which comes with multiple VMs: I don't have any refactoring to do at all: I can simply build my website as if it runs on my local hardware server, upload it to the VM offered by the cloud vendor, install it on the VM and I'm done. "But that might require changes to windows!" Yes, but Microsoft is Windows. Windows Azure is their service, they can make whatever change to what they offer to make it look like it's windows. Yet, they're stuck, like Amazon, in thinking in VMs, which forces developers to 'think ahead' and gamble whether they would need to migrate to a cloud with multiple VMs in the future or not. Which comes down to: gamble whether they should invest time in code / architecture which they might never need. (YAGNI anyone?) So the VM we're talking about, is that a low-level VM which runs a guest OS, or is that VM a different kind of VM? The flexible VM: .NET's CLR ? My example websites are ASP.NET based, which means they run inside a .NET appdomain, on the .NET CLR, which is a VM. The only physical OS resource the sites need is the file system, however this too is accessed through .NET. In short: all the websites see is what .NET allows the websites to see, the world as the websites know it is what .NET shows them and lets them access. How the .NET appdomain is run physically, that's the concern of .NET, not mine. This begs the question why Windows Azure doesn't offer virtual appdomains? Or better: .NET environments which look like one machine but could be physically multiple machines. In such an environment, no change has to be made to the websites to migrate them from a local machine or own server to the cloud to get proper scaling: the .NET VM will simply scale with the need: more memory needed, more CPU power needed, it stretches. What it offers to the application running inside the appdomain is simply increasing, but not fragmented: all resources are available to the application: this means that the problem of how to scale is back to where it should be: with the cloud vendor. "Yeah, great, but what about the databases?" The .NET application communicates with the database server through a .NET ADO.NET provider. Where the database is located is not a problem of the appdomain: the ADO.NET provider has to solve that. I.o.w.: we can host the databases in an environment which offers itself as a single resource and is accessible through one connection string without replication overhead on the outside, and use that environment inside the .NET VM as if it was a single DB. But what about memory replication and other problems? This environment isn't simple, at least not for the cloud vendor. But it is simple for the customer who wants to run his sites in that cloud: no work needed. No refactoring needed of existing code. Upload it, run it. Perhaps I'm dreaming and what I described above isn't possible. Yet, I think if cloud vendors don't move into that direction, what they're offering isn't interesting: it doesn't solve a problem at all, it simply offers a way to instantiate more VMs with the guest OS of choice at the cost of me needing to refactor my website code so it can run in the straight jacket form factor dictated by the cloud vendor. Let's not kid ourselves here: most of us developers will never build a website which needs a truck load of VMs to run it: almost all websites created by developers can run on just a few VMs at most. Yet, the most expensive change is right at the start: moving from one to two VMs. As soon as you have refactored your website code to run across multiple VMs, adding another one is just as easy as clicking a mouse button. But that first step, that's the problem here and as it's right there at the beginning of scaling the website, it's particularly strange that cloud vendors refuse to solve that problem and leave it to the developers to solve that. Which makes migrating 'to the cloud' particularly expensive.

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  • Code style Tip: Case insensitive string comparison

    - by Michael Freidgeim
    Goodif (String.Compare(myString, ALL_TEXT, StringComparison.OrdinalIgnoreCase) == 0)                                {                                         return true;                                }OK(not obvious what true means) if (String.Compare(myString, ALL_TEXT, true) == 0)                                {                                         return true;                                }BAD: (non null safe) if (myString.ToLower()==ALL_TEXT.ToLower()                                {                                         return true;                                }

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  • Integrating Coherence & Java EE 6 Applications using ActiveCache

    - by Ricardo Ferreira
    OK, so you are a developer and are starting a new Java EE 6 application using the most wonderful features of the Java EE platform like Enterprise JavaBeans, JavaServer Faces, CDI, JPA e another cool stuff technologies. And your architecture need to hold piece of data into distributed caches to improve application's performance, scalability and reliability? If this is your current facing scenario, maybe you should look closely in the solutions provided by Oracle WebLogic Server. Oracle had integrated WebLogic Server and its champion data caching technology called Oracle Coherence. This seamless integration between this two products provides a comprehensive environment to develop applications without the complexity of extra Java code to manage cache as a dependency, since Oracle provides an DI ("Dependency Injection") mechanism for Coherence, the same DI mechanism available in standard Java EE applications. This feature is called ActiveCache. In this article, I will show you how to configure ActiveCache in WebLogic and at your Java EE application. Configuring WebLogic to manage Coherence Before you start changing your application to use Coherence, you need to configure your Coherence distributed cache. The good news is, you can manage all this stuff without writing a single line of code of XML or even Java. This configuration can be done entirely in the WebLogic administration console. The first thing to do is the setup of a Coherence cluster. A Coherence cluster is a set of Coherence JVMs configured to form one single view of the cache. This means that you can insert or remove members of the cluster without the client application (the application that generates or consume data from the cache) knows about the changes. This concept allows your solution to scale-out without changing the application server JVMs. You can growth your application only in the data grid layer. To start the configuration, you need to configure an machine that points to the server in which you want to execute the Coherence JVMs. WebLogic Server allows you to do this very easily using the Administration Console. In this example, I will call the machine as "coherence-server". Remember that in order to the machine concept works, you need to ensure that the NodeManager are being executed in the target server that the machine points to. The NodeManager executable can be found in <WLS_HOME>/server/bin/startNodeManager.sh. The next thing to do is to configure a Coherence cluster. In the WebLogic administration console, go to Environment > Coherence Clusters and click in "New". Call this Coherence cluster of "my-coherence-cluster". Click in next. Specify a valid cluster address and port. The Coherence members will communicate with each other through this address and port. Our Coherence cluster are now configured. Now it is time to configure the Coherence members and add them to this cluster. In the WebLogic administration console, go to Environment > Coherence Servers and click in "New". In the field "Name" set to "coh-server-1". In the field "Machine", associate this Coherence server to the machine "coherence-server". In the field "Cluster", associate this Coherence server to the cluster named "my-coherence-cluster". Click in "Finish". Start the Coherence server using the "Control" tab of WebLogic administration console. This will instruct WebLogic to start a new JVM of Coherence in the target machine that should join the pre-defined Coherence cluster. Configuring your Java EE Application to Access Coherence Now lets pass to the funny part of the configuration. The first thing to do is to inform your Java EE application which Coherence cluster to join. Oracle had updated WebLogic server deployment descriptors so you will not have to change your code or the containers deployment descriptors like application.xml, ejb-jar.xml or web.xml. In this example, I will show you how to enable DI ("Dependency Injection") to a Coherence cache from a Servlet 3.0 component. In the WEB-INF/weblogic.xml deployment descriptor, put the following metadata information: <?xml version="1.0" encoding="UTF-8"?> <wls:weblogic-web-app xmlns:wls="http://xmlns.oracle.com/weblogic/weblogic-web-app" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd http://xmlns.oracle.com/weblogic/weblogic-web-app http://xmlns.oracle.com/weblogic/weblogic-web-app/1.4/weblogic-web-app.xsd"> <wls:context-root>myWebApp</wls:context-root> <wls:coherence-cluster-ref> <wls:coherence-cluster-name>my-coherence-cluster</wls:coherence-cluster-name> </wls:coherence-cluster-ref> </wls:weblogic-web-app> As you can see, using the "coherence-cluster-name" tag, we are informing our Java EE application that it should join the "my-coherence-cluster" when it loads in the web container. Without this information, the application will not be able to access the predefined Coherence cluster. It will form its own Coherence cluster without any members. So never forget to put this information. Now put the coherence.jar and active-cache-1.0.jar dependencies at your WEB-INF/lib application classpath. You need to deploy this dependencies so ActiveCache can automatically take care of the Coherence cluster join phase. This dependencies can be found in the following locations: - <WLS_HOME>/common/deployable-libraries/active-cache-1.0.jar - <COHERENCE_HOME>/lib/coherence.jar Finally, you need to write down the access code to the Coherence cache at your Servlet. In the following example, we have a Servlet 3.0 component that access a Coherence cache named "transactions" and prints into the browser output the content (the ammount property) of one specific transaction. package com.oracle.coherence.demo.activecache; import java.io.IOException; import javax.annotation.Resource; import javax.servlet.ServletException; import javax.servlet.annotation.WebServlet; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import com.tangosol.net.NamedCache; @WebServlet("/demo/specificTransaction") public class TransactionServletExample extends HttpServlet { @Resource(mappedName = "transactions") NamedCache transactions; protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { int transId = Integer.parseInt(request.getParameter("transId")); Transaction transaction = (Transaction) transactions.get(transId); response.getWriter().println("<center>" + transaction.getAmmount() + "</center>"); } } Thats it! No more configuration is necessary and you have all set to start producing and getting data to/from Coherence. As you can see in the example code, the Coherence cache are treated as a normal dependency in the Java EE container. The magic happens behind the scenes when the ActiveCache allows your application to join the defined Coherence cluster. The most interesting thing about this approach is, no matter which type of Coherence cache your are using (Distributed, Partitioned, Replicated, WAN-Remote) for the client application, it is just a simple attribute member of com.tangosol.net.NamedCache type. And its all managed by the Java EE container as an dependency. This means that if you inject the same dependency (the Coherence cache named "transactions") in another Java EE component (JSF managed-bean, Stateless EJB) the cache will be the same. Cool isn't it? Thanks to the CDI technology, we can extend the same support for non-Java EE standards components like simple POJOs. This means that you are not forced to only use Servlets, EJBs or JSF in order to inject Coherence caches. You can do the same approach for regular POJOs created for you and managed by lightweight containers like Spring or Seam.

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  • A Plea for Plain English

    - by Tony Davis
    The English language has, within a lifetime, emerged as the ubiquitous 'international language' of scientific, political and technical communication. On the one hand, learning a single, common language, International English, has made it much easier to participate in and adopt new technologies; on the other hand it must be exasperating to have to use English at international conferences, or on community sites, when your own language has a long tradition of scientific and technical usage. It is also hard to master the subtleties of using a foreign language to explain advanced ideas. This requires English speakers to be more considerate in their writing. Even if you’re used to speaking English, you may be brought up short by this sort of verbiage… "Business Intelligence delivering actionable insights is becoming more critical in the enterprise, and these insights require large data volumes for trending and forecasting" It takes some imagination to appreciate the added hassle in working out what it means, when English is a language you only use at work. Try, just to get a vague feel for it, using Google Translate to translate it from English to Chinese and back again. "Providing actionable business intelligence point of view is becoming more and more and more business critical, and requires that these insights and projected trends in large amounts of data" Not easy eh? If you normally use a different language, you will need to pause for thought before finally working out that it really means … "Every Business Intelligence solution must be able to help companies to make decisions. In order to detect current trends, and accurately predict future ones, we need to analyze large volumes of data" Surely, it is simple politeness for English speakers to stop peppering their writing with a twisted vocabulary that renders it inaccessible to everyone else. It isn’t just the problem of writers who use long words to give added dignity to their prose. It is the use of Colloquial English. This changes and evolves at a dizzying rate, adding new terms and idioms almost daily; it is almost a new and separate language. By contrast, ‘International English', is gradually evolving separately, at its own, more sedate, pace. As such, all native English speakers need to make an effort to learn, and use it, switching from casual colloquial patter into a simpler form of communication that can be widely understood by different cultures, even if it gives you less credibility on the street. Simple-Talk is based, at least in part, on the idea that technical articles can be written simply and clearly in a form of English that can be easily understood internationally, and that they can be written, with a little editorial help, by anyone, and read by anyone, regardless of their native language. Cheers, Tony.

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  • Pure Front end JavaScript with Web API versus MVC views with ajax

    - by eyeballpaul
    This was more a discussion for what peoples thoughts are these days on how to split a web application. I am used to creating an MVC application with all its views and controllers. I would normally create a full view and pass this back to the browser on a full page request, unless there were specific areas that I did not want to populate straight away and would then use DOM page load events to call the server to load other areas using AJAX. Also, when it came to partial page refreshing, I would call an MVC action method which would return the HTML fragment which I could then use to populate parts of the page. This would be for areas that I did not want to slow down initial page load, or areas that fitted better with AJAX calls. One example would be for table paging. If you want to move on to the next page, I would prefer it if an AJAX call got that info rather than using a full page refresh. But the AJAX call would still return an HTML fragment. My question is. Are my thoughts on this archaic because I come from a .net background rather than a pure front end background? An intelligent front end developer that I work with, prefers to do more or less nothing in the MVC views, and would rather do everything on the front end. Right down to web API calls populating the page. So that rather than calling an MVC action method, which returns HTML, he would prefer to return a standard object and use javascript to create all the elements of the page. The front end developer way means that any benefits that I normally get with MVC model validation, including client side validation, would be gone. It also means that any benefits that I get with creating the views, with strongly typed html templates etc would be gone. I believe this would mean I would need to write the same validation for front end and back end validation. The javascript would also need to have lots of methods for creating all the different parts of the DOM. For example, when adding a new row to a table, I would normally use the MVC partial view for creating the row, and then return this as part of the AJAX call, which then gets injected into the table. By using a pure front end way, the javascript would would take in an object (for, say, a product) for the row from the api call, and then create a row from that object. Creating each individual part of the table row. The website in question will have lots of different areas, from administration, forms, product searching etc. A website that I don't think requires to be architected in a single page application way. What are everyone's thoughts on this? I am interested to hear from front end devs and back end devs.

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