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• 4 Key Ingredients for the Cloud

  - by Kellsey Ruppel

  It's a short week here with the US Thanksgiving Holiday. So, before we put on our stretch pants and get ready to belly up to the dinner table for turkey, stuffing and mashed potatoes, let's spend a little time this week talking about the Cloud (kind of like the feathery whipped goodness that tops the infamous Thanksgiving pumpkin pie!) But before we dive into the Cloud, let's do a side by side comparison of the key ingredients for each. Cloud Whipped Cream  Application Integration  1 cup heavy cream  Security  1/4 cup sugar  Virtual I/O  1 teaspoon vanilla  Storage  Chilled Bowl It’s no secret that millions of people are connected to the Internet. And it also probably doesn’t come as a surprise that a lot of those people are connected on social networking sites.  Social networks have become an excellent platform for sharing and communication that reflects real world relationships and they play a major part in the everyday lives of many people. Facebook, Twitter, Pinterest, LinkedIn, Google+ and hundreds of others have transformed the way we interact and communicate with one another.Social networks are becoming more than just an online gathering of friends. They are becoming a destination for ideation, e-commerce, and marketing. But it doesn’t just stop there. Some organizations are utilizing social networks internally, integrated with their business applications and processes and the possibility of social media and cloud integration is compelling. Forrester alone estimates enterprise cloud computing to grow to over $240 billion by 2020. It’s hard to find any current IT project today that is NOT considering cloud-based deployments. Security and quality of service concerns are no longer at the forefront; rather, it’s about focusing on the right mix of capabilities for the business. Cloud vs. On-Premise? Policies & governance models? Social in the cloud? Cloud’s increasing sophistication, security in applications, mobility, transaction processing and social capabilities make it an attractive way to manage information. And Oracle offers all of this through the Oracle Cloud and Oracle Social Network. Oracle Social Network is a secure private network that provides a broad range of social tools designed to capture and preserve information flowing between people, enterprise applications, and business processes. By connecting you with your most critical applications, Oracle Social Network provides contextual, real-time communication within and across enterprises. With Oracle Social Network, you and your teams have the tools you need to collaborate quickly and efficiently, while leveraging the organization’s collective expertise to make informed decisions and drive business forward. Oracle Social Network is available as part of a portfolio of application and platform services within the Oracle Cloud. Oracle Cloud offers self-service business applications delivered on an integrated development and deployment platform with tools to rapidly extend and create new services. Oracle Social Network is pre-integrated with the Fusion CRM Cloud Service and the Fusion HCM Cloud Service within the Oracle Cloud. If you are looking for something to watch as you veg on the couch in a post-turkey dinner hangover, you might consider watching these how-to videos! And yes, it is perfectly ok to have that 2nd piece of pie

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• Revisiting the Generations

  - by Row Henson

  I was asked earlier this year to contribute an article to the IHRIM publication – Workforce Solutions Review.  My topic focused on the reality of the Gen Y population 10 years after their entry into the workforce.  Below is an excerpt from that article: It seems like yesterday that we were all talking about the entry of the Gen Y'ers into the workforce and what a radical change that would have on how we attract, retain, motivate, reward, and engage this new, younger segment of the workforce.  We all heard and read that these youngsters would be more entrepreneurial than their predecessors – the Gen X'ers – who were said to be more loyal to their profession than their employer. And, we heard that these “youngsters” would certainly be far less loyal to their employers than the Baby Boomers or even earlier Traditionalists. It was also predicted that – at least for the developed parts of the world – they would be more interested in work/life balance than financial reward; they would need constant and immediate reinforcement and recognition and we would be lucky to have them in our employment for two to three years. And, to keep them longer than that we would need to promote them often so they would be continuously learning since their long-term (10-year) goal would be to own their own business or be an independent consultant.  Well, it occurred to me recently that the first of the Gen Y'ers are now in their early 30s and it is time to look back on some of these predictions. Many really believed the Gen Y'ers would enter the workforce with an attitude – expect everything to be easy for them – have their employers meet their demands or move to the next employer, and I believe that we can now say that, generally, has not been the case. Speaking from personal experience, I have mentored a number of Gen Y'ers and initially felt that with a 40-year career in Human Resources and Human Resources Technology – I could share a lot with them. I found out very quickly that I was learning at least as much from them! Some of the amazing attributes I found from these under-30s was their fearlessness, ease of which they were able to multi-task, amazing energy and great technical savvy. They were very comfortable with collaborating with colleagues from both inside the company and peers outside their organization to problem-solve quickly. Most were eager to learn and willing to work hard.  This brings me to the generation that will follow the Gen Y'ers – the Generation Z'ers – those born after 1998. We have come full circle. If we look at the Silent Generation or Traditionalists, we find a workforce that preceded the television and even very early telephones. We Baby Boomers (as I fall right squarely in this category) remembered the invention of the television and telephone – but laptop computers and personal digital assistants (PDAs) were a thing of “StarTrek” and other science fiction movies and publications. Certainly, the Gen X'ers and Gen Y'ers grew up with the comfort of these devices just as we did with calculators. But, what of those under the age of 10 – how will the workplace look in 15 more years and what type of workforce will be required to operate in the mobile, global, virtual world. I spoke to a friend recently who had her four-year-old granddaughter for a visit. She said she found her in the den in front of the TV trying to use her hand to get the screen to move! So, you see – we have come full circle. The under-70 Traditionalist grew up in a world without TV and the Generation Z'er may never remember the TV we knew just a few years ago. As with every generation – we spend much time generalizing on their characteristics. The most important thing to remember is every generation – just like every individual – is different. The important thing for those of us in Human Resources to remember is that one size doesn’t fit all. What motivates one employee to come to work for you and stay there and be productive is very different than what the next employee is looking for and the organization that can provide this fluidity and flexibility will be the survivor for generations to come. And, finally, just when we think we have it figured out, a multitude of external factors such as the economy, world politics, industries, and technologies we haven’t even thought about will come along and change those predictions. As I reach retirement age – I do so believing that our organizations are in good hands with the generations to follow – energetic, collaborative and capable of working hard while still understanding the need for balance at work, at home and in the community! 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• Some Early Considerations

  - by Chris Massey

  Following on from my previous post, I want to say "thank you" to everyone who has got in touch and got involved – you are pioneers! An update on where we are right now: paper prototypes v1 To be more specific, we’ve picked two of the ideas that seem to have more pros than cons, turned them into Balsamiq mockups, and are getting them fleshed out with realistic content. We’ll initially make these available to the aforementioned pioneers (thank you again), roll in the feedback, and then open up to get more data on what works and what doesn’t. If you’ve got any questions about this (or what we’re working on right now), feel free to ask me in the comments below. I’ve had a few people express an interest in the process we’re going through, and I’m more than happy to share details more frequently as we go along – not least because you, dear reader, will help us stay on target and create something Good. To start with, here’s a quick flashback to bring you all up to speed. A Brief Retrospective As you may already know, we’re creating a new publishing asset specifically focused on providing great content for web developers. We don’t yet know exactly what this thing will look like, or exactly how it will work, but we know we want to create something that is useful different. For my part, I’m seriously excited at the prospect of building a genuinely digital publishing system (as opposed to what most publishing is these days, which is print-style publishing which just happens to be on the web). The main challenge at this point is working out our build-measure-assess loop to speed up our experimental turn-around, and that’ll get better as we run more trials. Of course, there are a few things we’ve been pondering at this early conceptual stage: Do we publishing about heterogeneous technology stacks from day 1, or do we start with ASP.NET (which we’re familiar with) & branch out later? There are challenges with either approach. What publishing "modes" are already being well-handled? For example, the likes of Pluralsight, TekPub, and Treehouse have pretty much nailed video training (debate about price, if you like), and unless we think we can do it faster / better / cheaper (unlikely, for the record), we should leave them to it. Where should we base whatever we create? Should we create a completely new asset under a new name, graft something onto Simple-Talk (like the labs), or just build something directly into Simple-Talk? It sounds trivial, but it does have at least some impact on infrastructure and what how we manage the different types of content we (will) have. Are there any obvious problems or niches that we think could address really well, or should we just throw ideas out and see what readers respond to? What kind of users do we want to provide for? This actually deserves a little bit of unpacking… Why are you here? We currently divide readers into (broadly) the categories: Category 1: I know nothing about X, and I’d like to learn about it. Category 2: I know something about X, but I’d like to learn how to do something specific with it. Category 3: Ah man, I have a problem with X, and I need to fix it now. Now that I think about it, I might also include a 4th class of reader: Category 4: I’m looking for something interesting to engage my brain. These are clearly task-based categorizations, and depending on which task you’re performing when you arrive here, you’re going to need different types of content, or will have specific discovery needs. One of the questions that’s at the back of my mind whenever I consider a new idea is “How many of the categories will this satisfy?” As an example, typical video training is very well suited to categories 1, 2, and 4. StackOverflow is very well suited to category 3, and serves as a sign-posting system to the rest. Clearly it’s not necessary to satisfy every category need to be useful and popular, but being aware of what behavior readers might be exhibiting when they arrive will help us tune our ideas appropriately. < / Flashback > We don’t have clean answers to most of these considerations – they’re things we’re aware of, and each idea we look at is going to be best suited to a different mix of the options I’ve described. Our first experimental loop will be coming full circle in the next few days, so we should start to see how the different possibilities vary between ideas. Free to chime in with questions and suggestions about anything I’ve just brain-dumped, or at any stage as we go along. If you see anything that intrigued or enrages you, or just have an idea you’d like to share, I’d love to hear from you.

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• Hopping/Tumbling Windows Could Introduce Latency.

  This is a pre-article to one I am going to be writing on adjusting an event’s time and duration to satisfy business process requirements but it is one that I think is really useful when understanding the way that Hopping/Tumbling windows work within StreamInsight.  A Tumbling window is just a special shortcut version of  a Hopping window where the width of the window is equal to the size of the hop Here is the simplest and often used definition for a Hopping Window.  You can find them all here public static CepWindowStream<CepWindow<TPayload>> HoppingWindow<TPayload>(     this CepStream<TPayload> source,     TimeSpan windowSize,     TimeSpan hopSize,     WindowInputPolicy inputPolicy,     HoppingWindowOutputPolicy outputPolicy )   And here is the definition for a Tumbling Window public static CepWindowStream<CepWindow<TPayload>> TumblingWindow<TPayload>(     this CepStream<TPayload> source,     TimeSpan windowSize,     WindowInputPolicy inputPolicy,     HoppingWindowOutputPolicy outputPolicy )   These methods allow you to group events into windows of a temporal size.  It is a really useful and simple feature in StreamInsight.  One of the downsides though is that the windows cannot be flushed until an event in a following window occurs.  This means that you will potentially never see some events or see them with a delay.  Let me explain. Remember that a stream is a potentially unbounded sequence of events. Events in StreamInsight are given a StartTime.  It is this StartTime that is used to calculate into which temporal window an event falls.  It is best practice to assign a timestamp from the source system and not one from the system clock on the processing server.  StreamInsight cannot know when a window is over.  It cannot tell whether you have received all events in the window or whether some events have been delayed which means that StreamInsight cannot flush the stream for you.   Imagine you have events with the following Timestamps 12:10:10 PM 12:10:20 PM 12:10:35 PM 12:10:45 PM 11:59:59 PM And imagine that you have defined a 1 minute Tumbling Window over this stream using the following syntax var HoppingStream = from shift in inputStream.TumblingWindow(TimeSpan.FromMinutes(1),HoppingWindowOutputPolicy.ClipToWindowEnd) select new WindowCountPayload { CountInWindow = (Int32)shift.Count() };   The events between 12:10:10 PM and 12:10:45 PM will not be seen until the event at 11:59:59 PM arrives.  This could be a real problem if you need to react to windows promptly This can always be worked around by using a different design pattern but a lot of the examples I see assume there is a constant, very frequent stream of events resulting in windows always being flushed. Further examples of using windowing in StreamInsight can be found here

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• What Counts for A DBA: Observant

  - by drsql

  When walking up to the building where I work, I can see CCTV cameras placed here and there for monitoring access to the building. We are required to wear authorization badges which could be checked at any time. Do we have enemies?  Of course! No one is 100% safe; even if your life is a fairy tale, there is always a witch with an apple waiting to snack you into a thousand years of slumber (or at least so I recollect from elementary school.) Even Little Bo Peep had to keep a wary lookout.    We nerdy types (or maybe it was just me?) generally learned on the school playground to keep an eye open for unprovoked attack from simpler, but more muscular souls, and take steps to avoid messy confrontations well in advance. After we’d apprehensively negotiated adulthood with varying degrees of success, these skills of watching for danger, and avoiding it,  translated quite well to the technical careers so many of us were destined for. And nowhere else is this talent for watching out for irrational malevolence so appropriate as in a career as a production DBA.   It isn’t always active malevolence that the DBA needs to watch out for, but the even scarier quirks of common humanity.  A large number of the issues that occur in the enterprise happen just randomly or even just one time ever in a spurious manner, like in the case where a person decided to download the entire MSDN library of software, cross join every non-indexed billion row table together, and simultaneously stream the HD feed of 5 different sporting events, making the network access slow while the corporate online sales just started. The decent DBA team, like the going, gets tough under such circumstances. They spring into action, checking all of the sources of active information, observes the issue is no longer happening now, figures that either it wasn’t the database’s fault and that the reboot of the whatever device on the network fixed the problem.  This sort of reactive support is good, and will be the initial reaction of even excellent DBAs, but it is not the end of the story if you really want to know what happened and avoid getting called again when it isn’t even your fault.   When fires start raging within the corporate software forest, the DBA’s instinct is to actively find a way to douse the flames and get back to having no one in the company have any idea who they are.  Even better for them is to find a way of killing a potential problem while the fires are small, long before they can be classified as raging. The observant DBA will have already been monitoring the server environment for months in advance.  Most troubles, such as disk space and security intrusions, can be predicted and dealt with by alerting systems, whereas other trouble can come out of the blue and requires a skill of observing ongoing conditions and noticing inexplicable changes that could signal an emerging problem.  You can’t automate the DBA, because the bankable skill of a DBA is in detecting the early signs of unexpected problems, and working out how to deal with them before anyone else notices them.    To achieve this, the DBA will check the situation as it is currently happening,  and in many cases is likely to have been the person who submitted the problem to the level 1 support person in the first place, just to let the support team know of impending issues (always well received, I tell you what!). Database and host computer settings, configurations, and even critical data might be profiled and captured for later comparisons. He’ll use Monitoring tools, built-in, commercial (Not to be too crassly commercial or anything, but there is one such tool is SQL Monitor) and lots of homebrew monitoring tools to monitor for problems and changes in the server environment.   You will know that you have it right when a support call comes in and you can look at your monitoring tools and quickly respond that “response time is well within the normal range, the query that supports the failing interface works perfectly and has actually only been called 67% as often as normal, so I am more than willing to help diagnose the problem, but it isn’t the database server’s fault and is probably a client or networking slowdown causing the interface to be used less frequently than normal.” And that is the best thing for any DBA to observe…

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• Custom Text and Binary Payloads using WebSocket (TOTD #186)

  - by arungupta

  TOTD #185 explained how to process text and binary payloads in a WebSocket endpoint. In summary, a text payload may be received as public void receiveTextMessage(String message) {    . . . } And binary payload may be received as: public void recieveBinaryMessage(ByteBuffer message) {    . . .} As you realize, both of these methods receive the text and binary data in raw format. However you may like to receive and send the data using a POJO. This marshaling and unmarshaling can be done in the method implementation but JSR 356 API provides a cleaner way. For encoding and decoding text payload into POJO, Decoder.Text (for inbound payload) and Encoder.Text (for outbound payload) interfaces need to be implemented. A sample implementation below shows how text payload consisting of JSON structures can be encoded and decoded. public class MyMessage implements Decoder.Text<MyMessage>, Encoder.Text<MyMessage> {     private JsonObject jsonObject;    @Override    public MyMessage decode(String string) throws DecodeException {        this.jsonObject = new JsonReader(new StringReader(string)).readObject();               return this;    }     @Override    public boolean willDecode(String string) {        return true;    }     @Override    public String encode(MyMessage myMessage) throws EncodeException {        return myMessage.jsonObject.toString();    } public JsonObject getObject() { return jsonObject; }} In this implementation, the decode method decodes incoming text payload to MyMessage, the encode method encodes MyMessage for the outgoing text payload, and the willDecode method returns true or false if the message can be decoded. The encoder and decoder implementation classes need to be specified in the WebSocket endpoint as: @WebSocketEndpoint(value="/endpoint", encoders={MyMessage.class}, decoders={MyMessage.class}) public class MyEndpoint { public MyMessage receiveMessage(MyMessage message) { . . . } } Notice the updated method signature where the application is working with MyMessage instead of the raw string. Note that the encoder and decoder implementations just illustrate the point and provide no validation or exception handling. Similarly Encooder.Binary and Decoder.Binary interfaces need to be implemented for encoding and decoding binary payload. Here are some references for you: JSR 356: Java API for WebSocket - Specification (Early Draft) and Implementation (already integrated in GlassFish 4 promoted builds) TOTD #183 - Getting Started with WebSocket in GlassFish TOTD #184 - Logging WebSocket Frames using Chrome Developer Tools, Net-internals and Wireshark TOTD #185: Processing Text and Binary (Blob, ArrayBuffer, ArrayBufferView) Payload in WebSocket Subsequent blogs will discuss the following topics (not necessary in that order) ... Error handling Interface-driven WebSocket endpoint Java client API Client and Server configuration Security Subprotocols Extensions Other topics from the API

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• Using WKA in Large Coherence Clusters (Disabling Multicast)

  - by jpurdy

  Disabling hardware multicast (by configuring well-known addresses aka WKA) will place significant stress on the network. For messages that must be sent to multiple servers, rather than having a server send a single packet to the switch and having the switch broadcast that packet to the rest of the cluster, the server must send a packet to each of the other servers. While hardware varies significantly, consider that a server with a single gigabit connection can send at most ~70,000 packets per second. To continue with some concrete numbers, in a cluster with 500 members, that means that each server can send at most 140 cluster-wide messages per second. And if there are 10 cluster members on each physical machine, that number shrinks to 14 cluster-wide messages per second (or with only mild hyperbole, roughly zero). It is also important to keep in mind that network I/O is not only expensive in terms of the network itself, but also the consumption of CPU required to send (or receive) a message (due to things like copying the packet bytes, processing a interrupt, etc). Fortunately, Coherence is designed to rely primarily on point-to-point messages, but there are some features that are inherently one-to-many: Announcing the arrival or departure of a member Updating partition assignment maps across the cluster Creating or destroying a NamedCache Invalidating a cache entry from a large number of client-side near caches Distributing a filter-based request across the full set of cache servers (e.g. queries, aggregators and entry processors) Invoking clear() on a NamedCache The first few of these are operations that are primarily routed through a single senior member, and also occur infrequently, so they usually are not a primary consideration. There are cases, however, where the load from introducing new members can be substantial (to the point of destabilizing the cluster). Consider the case where cluster in the first paragraph grows from 500 members to 1000 members (holding the number of physical machines constant). During this period, there will be 500 new member introductions, each of which may consist of several cluster-wide operations (for the cluster membership itself as well as the partitioned cache services, replicated cache services, invocation services, management services, etc). Note that all of these introductions will route through that one senior member, which is sharing its network bandwidth with several other members (which will be communicating to a lesser degree with other members throughout this process). While each service may have a distinct senior member, there's a good chance during initial startup that a single member will be the senior for all services (if those services start on the senior before the second member joins the cluster). It's obvious that this could cause CPU and/or network starvation. In the current release of Coherence (3.7.1.3 as of this writing), the pure unicast code path also has less sophisticated flow-control for cluster-wide messages (compared to the multicast-enabled code path), which may also result in significant heap consumption on the senior member's JVM (from the message backlog). This is almost never a problem in practice, but with sufficient CPU or network starvation, it could become critical. For the non-operational concerns (near caches, queries, etc), the application itself will determine how much load is placed on the cluster. Applications intended for deployment in a pure unicast environment should be careful to avoid excessive dependence on these features. Even in an environment with multicast support, these operations may scale poorly since even with a constant request rate, the underlying workload will increase at roughly the same rate as the underlying resources are added. Unless there is an infrastructural requirement to the contrary, multicast should be enabled. If it can't be enabled, care should be taken to ensure the added overhead doesn't lead to performance or stability issues. This is particularly crucial in large clusters.

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• Is the Leptonica implementation of 'Modified Median Cut' not using the median at all?

  - by TheCodeJunkie

  I'm playing around a bit with image processing and decided to read up on how color quantization worked and after a bit of reading I found the Modified Median Cut Quantization algorithm. I've been reading the code of the C implementation in Leptonica library and came across something I thought was a bit odd. Now I want to stress that I am far from an expert in this area, not am I a math-head, so I am predicting that this all comes down to me not understanding all of it and not that the implementation of the algorithm is wrong at all. The algorithm states that the vbox should be split along the lagest axis and that it should be split using the following logic The largest axis is divided by locating the bin with the median pixel (by population), selecting the longer side, and dividing in the center of that side. We could have simply put the bin with the median pixel in the shorter side, but in the early stages of subdivision, this tends to put low density clusters (that are not considered in the subdivision) in the same vbox as part of a high density cluster that will outvote it in median vbox color, even with future median-based subdivisions. The algorithm used here is particularly important in early subdivisions, and 3is useful for giving visible but low population color clusters their own vbox. This has little effect on the subdivision of high density clusters, which ultimately will have roughly equal population in their vboxes. For the sake of the argument, let's assume that we have a vbox that we are in the process of splitting and that the red axis is the largest. In the Leptonica algorithm, on line 01297, the code appears to do the following Iterate over all the possible green and blue variations of the red color For each iteration it adds to the total number of pixels (population) it's found along the red axis For each red color it sum up the population of the current red and the previous ones, thus storing an accumulated value, for each red note: when I say 'red' I mean each point along the axis that is covered by the iteration, the actual color may not be red but contains a certain amount of red So for the sake of illustration, assume we have 9 "bins" along the red axis and that they have the following populations 4 8 20 16 1 9 12 8 8 After the iteration of all red bins, the partialsum array will contain the following count for the bins mentioned above 4 12 32 48 49 58 70 78 86 And total would have a value of 86 Once that's done it's time to perform the actual median cut and for the red axis this is performed on line 01346 It iterates over bins and check they accumulated sum. And here's the part that throws me of from the description of the algorithm. It looks for the first bin that has a value that is greater than total/2 Wouldn't total/2 mean that it is looking for a bin that has a value that is greater than the average value and not the median ? The median for the above bins would be 49 The use of 43 or 49 could potentially have a huge impact on how the boxes are split, even though the algorithm then proceeds by moving to the center of the larger side of where the matched value was.. Another thing that puzzles me a bit is that the paper specified that the bin with the median value should be located, but does not mention how to proceed if there are an even number of bins.. the median would be the result of (a+b)/2 and it's not guaranteed that any of the bins contains that population count. So this is what makes me thing that there are some approximations going on that are negligible because of how the split actually takes part at the center of the larger side of the selected bin. Sorry if it got a bit long winded, but I wanted to be as thoroughas I could because it's been driving me nuts for a couple of days now ;)

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• Don’t string together XML

  - by KyleBurns

  XML has been a pervasive tool in software development for over a decade.  It provides a way to communicate data in a manner that is simple to understand and free of platform dependencies.  Also pervasive in software development is what I consider to be the anti-pattern of using string manipulation to create XML.  This usually starts with a “quick and dirty” approach because you need an XML document and looks like (for all of the examples here, we’ll assume we’re writing the body of a method intended to take a Contact object and return an XML string): return string.Format("<Contact><BusinessName>{0}</BusinessName></Contact>", contact.BusinessName);   In the code example, I created (or at least believe I created) an XML document representing a simple contact object in one line of code with very little overhead.  Work’s done, right?  No it’s not.  You see, what I didn’t realize was that this code would be used in the real world instead of my fantasy world where I own all the data and can prevent any of it containing problematic values.  If I use this code to create a contact record for the business “Sanford & Son”, any XML parser will be incapable of processing the data because the ampersand is special in XML and should have been encoded as &amp;. Following the pattern that I have seen many times over, my next step as a developer is going to be to do what any developer in his right mind would do – instruct the user that ampersands are “bad” and they cannot be used without breaking computers.  This may work in many cases and is often accompanied by logic at the UI layer of applications to block these “bad” characters, but sooner or later someone is going to figure out that other applications allow for them and will want the same.  This often leads to the creation of “cleaner” functions that perform a replace on the strings for every special character that the person writing the function can think of.  The cleaner function will usually grow over time as support requests reveal characters that were missed in the initial cut.  Sooner or later you end up writing your own somewhat functional XML engine. I have never been told by anyone paying me to write code that they would like to buy a somewhat functional XML engine.  My employer/customer’s needs have always been for something that may use XML, but ultimately is functionality that drives business value. I’m not going to build an XML engine. So how can I generate XML that is always well-formed without writing my own engine?  Easy – use one of the ones provided to you for free!  If you’re in a shop that still supports VB6 applications, you can use the DomDocument or MXXMLWriter object (of the two I prefer MXXMLWriter, but I’m not going to fully describe either here).  For .Net Framework applications prior to the 3.5 framework, the code is a little more verbose than I would like, but easy once you understand what pieces are required:             using (StringWriter sw = new StringWriter())             {                 using (XmlTextWriter writer = new XmlTextWriter(sw))                 {                     writer.WriteStartDocument();                     writer.WriteStartElement("Contact");                     writer.WriteElementString("BusinessName", contact.BusinessName);                     writer.WriteEndElement(); // end Contact element                     writer.WriteEndDocument();                     writer.Flush();                     return sw.ToString();                 }             }   Looking at that code, it’s easy to understand why people are drawn to the initial one-liner.  Lucky for us, the 3.5 .Net Framework added the System.Xml.Linq.XElement object.  This object takes away a lot of the complexity present in the XmlTextWriter approach and allows us to generate the document as follows: return new XElement("Contact", new XElement("BusinessName", contact.BusinessName)).ToString();   While it is very common for people to use string manipulation to create XML, I’ve discussed here reasons not to use this method and introduced powerful APIs that are built into the .Net Framework as an alternative.  I’ve given a very simplistic example here to highlight the most basic XML generation task.  For more information on the XmlTextWriter and XElement APIs, check out the MSDN library.

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• Qt vs WPF/.NET

  - by aaronc

  My company is trying to make the decision between using Qt/C++ for our GUI framework or migrating to .NET and using WPF. We have up to this point been using MFC. It seems that .NET/WPF is technically the most advanced and feature-rich platform. I do, however, have several concerns. These include: Platform support Framework longevity (i.e. future-proofing) Performance and overhead For this application we are willing to sacrifice support for Windows 2000, Macs, and Linux. But, the issue is more related to Microsoft's commitment to the framework and their extant platforms. It seems like Microsoft has a bad habit of coming up with something new, hyping it for a few years, and then relegating it to the waste-bin essentially abandoning the developers who chose it. First it was MFC and VB6, then Windows Forms, and now there's WPF. Also with .NET, versions of Windows were progressively nicked off the support list. Looks like WPF could be here to stay for a while, but since its not open source its really in Microsoft's hands. I'm also concerned about the overhead and performance of WPF since some of our applications involve processing large amounts of information and doing real-time data capture. Qt seems like a really good option, but it doesn't have all the features of WPF/.NET couldn't use languages like C#. Basically, what does the community think about Microsoft's commitment to WPF compared with previous frameworks? Are the performance considerations significant enough to avoid using it for a realtime app? And, how significant are the benefits of WPF/.NET in terms of productivity and features compared to Qt?

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• Using ReportViewer 9 control in VS 2010

  - by Fermin

  Hi, I am writing an ASP.NET app that uses a SQL Server 2005 with SSRS setup. I want to use the ReportViewer control but I get an error when using ReportViewer 10 because it needs SSRS 2008. How can I use ReportViewer 9 within my application. I've added a reference to the Microsoft.ReportViewer.WebForms.dll version 9 and removed the reference to version 10. My markup is as follows: <%@ Register Assembly="Microsoft.ReportViewer.WebForms, Version=9.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a" Namespace="Microsoft.Reporting.WebForms" TagPrefix="rsweb" %> <!-- standard markup --> <rsweb:ReportViewer ID="ReportViewer1" runat="server"></rsweb:ReportViewer> but when I try to run this I get the following error: CS0433: The type 'Microsoft.Reporting.WebForms.ReportViewer' exists in both 'c:\WINDOWS\assembly\GAC_MSIL\Microsoft.ReportViewer.WebForms\10.0.0.0__b03f5f7f11d50a3a\Microsoft.ReportViewer.WebForms.dll' and 'c:\WINDOWS\assembly\GAC_MSIL\Microsoft.ReportViewer.WebForms\9.0.0.0__b03f5f7f11d50a3a\Microsoft.ReportViewer.WebForms.dll' What have I missed!? Update: When trying to use the ReportViewer 10 I get the following error: "Remote report processing requires Microsoft SQL Server 2008 Reporting Services or later."

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• bulk insert and update with ADO.NET Entity Framework

  - by Keith Barrows

  I am writing a small application that does a lot of feed processing. I want to use LINQ EF for this as speed is not an issue, it is a single user app and, in the end, will only be used once a month. My questions revolves around the best way to do bulk inserts using LINQ EF. After parsing the incoming data stream I end up with a List of values. Since the end user may end up trying to import some duplicate data I would like to "clean" the data during insert rather than reading all the records, doing a for loop, rejecting records, then finally importing the remainder. This is what I am currently doing: DateTime minDate = dataTransferObject.Min(c => c.DoorOpen); DateTime maxDate = dataTransferObject.Max(c => c.DoorOpen); using (LabUseEntities myEntities = new LabUseEntities()) { var recCheck = myEntities.ImportDoorAccess.Where(a => a.DoorOpen >= minDate && a.DoorOpen <= maxDate).ToList(); if (recCheck.Count > 0) { foreach (ImportDoorAccess ida in recCheck) { DoorAudit da = dataTransferObject.Where(a => a.DoorOpen == ida.DoorOpen && a.CardNumber == ida.CardNumber).First(); if (da != null) da.DoInsert = false; } } ImportDoorAccess newIDA; foreach (DoorAudit newDoorAudit in dataTransferObject) { if (newDoorAudit.DoInsert) { newIDA = new ImportDoorAccess { CardNumber = newDoorAudit.CardNumber, Door = newDoorAudit.Door, DoorOpen = newDoorAudit.DoorOpen, Imported = newDoorAudit.Imported, RawData = newDoorAudit.RawData, UserName = newDoorAudit.UserName }; myEntities.AddToImportDoorAccess(newIDA); } } myEntities.SaveChanges(); } I am also getting this error: System.Data.UpdateException was unhandled Message="Unable to update the EntitySet 'ImportDoorAccess' because it has a DefiningQuery and no element exists in the element to support the current operation." Source="System.Data.SqlServerCe.Entity" What am I doing wrong? Any pointers are welcome.

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• WPF WriteableBitmap Memory Leak?

  - by Mario

  Hello, everyone! I'm trying to figure out how to release a WriteableBitmap memory. In the next section of code I fill the backbuffer of a WriteableBitmap with a really large amount of data from "BigImage" (3600 * 4800 px, just for testing) If I comment the lines where bitmap and image are equaled to null, the memory it´s not release and the application consumes ~230 MB, even when Image and bitmap are no longer used! As you can see at the end of the code its necessary to call GC.Collect() to release the memory. So the question is, what is the right way to free the memory used by a WriteableBitmap object? Is GC.Collect() the only way? Any help would be great. PS. Sorry for my bad english. private void buttonTest_Click(object sender, RoutedEventArgs e) { Image image = new Image(); image.Source = new BitmapImage(new Uri("BigImage")); WriteableBitmap bitmap = new WriteableBitmap( (BitmapSource)image.Source); bitmap.Lock(); // Bitmap processing bitmap.Unlock(); image = null; bitmap = null; GC.Collect(); }

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• WinForms ReportViewer: slow initial rendering

  - by Bryan Roth

  UPDATE 2.4.2010 Yeah, this is an old question but I thought I would give an update. So, I'm working with the ReportViewer again and it's still rendering slowly on the initial load. The only difference is that the SQL database is on the reporting server. UPDATE 3.16.2009 I have done profiling and it's not the SQL that is making the ReportViewer render slowly on the first call. On the first call, the ReportViewer control locks up the UI thread and makes the program unresponsive. After about 5 seconds the ReportViewer will unlock the UI thread and display "Report is being generated" and then finally show the report. I know 5 seconds is not much but this shouldn't be happening. My coworker does the same thing in a program of his and the ReportViewer immediately displays the "Report is being generated" upon any request. The only difference is that the reporting server is on one server and the data is on another server. However, when I am developing the reports within SSRS, there is no delay. UPDATE I have noticed that only the first load of the ReportViewer takes a long time; each subsequent load of the same or different reports loads fast. I have a WinForms ReportViewer that I'm using in Remote processing mode that can take up to 30 seconds to render when the ReportViewer.RefreshReport() method is called. However, the report itself runs fast. This is the code to setup my ReportViewer: rvReport.ProcessingMode = ProcessingMode.Remote rvReport.ShowParameterPrompts = False rvReport.ServerReport.ReportServerUrl = New Uri(_reportServerURL) rvReport.ServerReport.ReportPath = _reportPath This is where the ReportViewer can take up to 30 seconds to render: rvReport.RefreshReport()

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• sort django queryset by latest instance of a subset of related model

  - by rsp

  I have an Order model and order_event model. Each order_event has a foreignkey to order. so from an order instance i can get: myorder.order_event_set. I want to get a list of all orders but i want them to be sorted by the date of the last event. A statement like this works to sort by the latest event date: queryset = Order.objects.all().annotate(latest_event_date=Max('order_event__event_datetime')).order_by('latest_event_date') However, what I really need is a list of all orders sorted by latest date of A SUBSET OF EVENTS. For example my events are categorized into "scheduling", "processing", etc. So I should be able to get a list of all orders sorted by the latest scheduling event. This django doc (https://docs.djangoproject.com/en/dev/topics/db/aggregation/#filter-and-exclude) shows how I can get the latest schedule event using a filter but this excludes orders without a scheduling event. I thought I could combine the filtered queryset with a queryset that includes back those orders that are missing a scheduling event...but I'm not quite sure how to do this. I saw answers related to using python list but it would be much more useful to have a proper django queryset (ie for a view with pagination, etc.)

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• Application error: fault address 0x00012afb (Expert)

  - by Christian Almeida

  Hi, I need some "light" to get a solution. Probably there are tons of things that cause this problem, but maybe somebody could help me. Scenario: a Windows server running 24/7 a PostgreSQL database and others server applications (for processing tasks on database, etc...). There are differents servers scenarios (~30), with different hardware and windows versions (XP SP3/ WinServer, etc... all NT based). All aplications were written in Delphi7, and link to DLLs (in D7 also). After some days (sometimes a week, sometimes a couple of months), Windows begins to act strange, like not opening start menu, some buttons are missing in dialogs. And soon some applications do not open, raising a event on eventviewer: Faulting application x, version y, faulting module kernel32.dll, version 5.1.2600.5781, fault address 0x00012afb In mean while, others applications open fine, like notepad, iexplore, etc... but SOME of my applications don't, with only event log described above. But if we do not restart system, in a few days even cmd.exe stops open, (and all other applications) with same error on eventlog. I've tried to find 'what' can cause this, but with no sucess. So, and any advice will be welcome. Thanks in advance.

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• IIS7 Mixed Mode Authentication

  - by drachenstern

  We're getting ready to start migrating some of our IIS6 sites to IIS7, and the application currently uses Forms Authentication. We have started getting some requests from various sites to use the Windows Authentication for the users. While this is easy enough to implement (and I've shown internally that there is no issue with the app, as expected) the question then is how to continue to keep Forms authentication for when Integrated Windows doesn't work. I've seen several walkthroughs on how to have it configured on IIS6, and I could do the same thing on IIS7, but then I have to turn on Classic Mode processing. Any solution should also be back portable to IIS6, if possible, to keep the build tree simple. So what are my options on this? Do I setup the app with Integrated Windows Authentication in IIS7, Forms Auth in the web.config, and redirect 401 errors to an "error page" allowing them to login using forms, then back to the regular app? The case when Forms is likely to be needed is going to be reserved for Contract workers, our support staff, and if someone needs to access it on their site from their Extranet. So primarily it's for our staff to login to check functionality and confirm bug reports. I suggested we just maintain that for our support staff to work, we need a Windows login that will always be live, and then we'll just enforce local responsibility on who can login to the site, but I'm told that we would do better to have Forms Authentication. Any thoughts? I can post some of the links of the articles I've already read through if that would help the forum better narrow my needs. Many thanks. tl;dr: How to do mixed mode authentication (forms, windows) in IIS7 without changing to classic pipeline and still be able to use the build in IIS6 if possible.

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• How to reclaim storage for deleted LOBs

  - by Jim Hudson

  I have a LOB tablespace. Currently holding 9GB out of 12GB available. And, as far as I can tell, deleting records doesn't reclaim any storage in the tablespace. I'm getting worried about handling further processing. This is Oracle 11.1 and the data are in a CLOB and a BLOB column in the same table. The LOB Index segments (SYS_IL...) are small, all the storage is in the data segments (SYS_LOB...) We'e tried purge and coalesce and didn't get anywhere -- same number of bytes in user_extents. "Alter table xxx move" will work, but we'd need to have someplace to move it to that has enough space for the revised data. We'd also need to do that off hours and rebuild the indexes, of course, but that's easy enough. Copying out the good data and doing a truncate, then copying it back, will also work. But that's pretty much just what the "alter table" command does. Am I missing some easy ways to shrink things down and get the storage back? Or is "alter table xxx move" the best approach? Or is this a non-issue and Oracle will grab back the space from the deleted lob rows when it needs it?

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• Update text in StatusBar in wpf using C#

  - by Archie

  hello, I have a TextBox in StatusBar in wpf which i want to update. I have a list of files in ListBox. On each file I would be doing some operation by calling say method ProcessFile(). So whenever the file processing is completed I want to show that file's name in the StatusBar text. I have tried something like this: private void button_Click(object sender, RoutedEventArgs e) { statusBar.Visibility = Visibility.Visible; DispatcherFrame frame = new DispatcherFrame(); Dispatcher.CurrentDispatcher.BeginInvoke(DispatcherPriority.Background, new DispatcherOperationCallback(TimeConsumingMethod), frame); Dispatcher.PushFrame(frame); statusBar.Visibility = Visibility.Collapsed; } public object TimeConsumingMethod(Object arg) { ((DispatcherFrame)arg).Continue = false; foreach (string fileName in destinationFilesList.Items) { txtStatus.Text = fileName.ToString(); //Assume that each process takes some time to complete System.Threading.Thread.Sleep(1000); } return null; } But i can only see the last file's name in the StatusBar. Whats wrong with the code? Can somebody correct it? Thanks.

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• Entity Framework 4 Code First and the new() Operator

  - by Eric J.

  I have a rather deep hierarchy of objects that I'm trying to persist with Entity Framework 4, POCO, PI (Persistence Ignorance) and Code First. Suddenly things started working pretty well when it dawned on me to not use the new() operator. As originally written, the objects frequently use new() to create child objects. Instead I'm using my take on the Repository Pattern to create all child objects as needed. For example, given: class Adam { List<Child> children; void AddChildGivenInput(string input) { children.Add(new Child(...)); } } class Child { List<GrandChild> grandchildren; void AddGrandChildGivenInput(string input) { grandchildren.Add(new GrandChild(...)); } } class GrandChild { } ("GivenInput" implies some processing not shown here) I define an AdamRepository like: class AdamRepository { Adam Add() { return objectContext.Create<Adam>(); } Child AddChildGivenInput(Adam adam, string input) { return adam.children.Add(new Child(...)); } GrandChild AddGrandchildGivenInput(Child child, string input) { return child.grandchildren.Add(new GrandChild(...)); } } Now, this works well enough. However, I'm no longer "ignorant" of my persistence mechanism as I have abandoned the new() operator. Additionally, I'm at risk of an anemic domain model since so much logic ends up in the repository rather than in the domain objects. After much adieu, a question: Or rather several questions... Is this pattern required to work with EF 4 Code First? Is there a way to retain use of new() and still work with EF 4 / POCO / Code First? Is there another pattern that would leave logic in the domain object and still work with EF 4 / POCO / Code First? Will this restriction be lifted in later versions of Code First support? Sometimes trying to go the POCO / Persistence Ignorance route feels like swimming upstream, other times it feels like swimming up Niagra Falls.

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• WCF - The maximum nametable character count quota (16384) has been exceeded while reading XML data.

  - by Jankhana

  I'm having a WCF Service that uses wsHttpBinding. The server configuration is as follows : <bindings> <wsHttpBinding> <binding name="wsHttpBinding" maxBufferPoolSize="2147483647" maxReceivedMessageSize="2147483647"> <readerQuotas maxDepth="2147483647" maxStringContentLength="2147483647" maxArrayLength="2147483647" maxBytesPerRead="2147483647" maxNameTableCharCount="2147483647" /> <security mode="None"> <transport clientCredentialType="Windows" proxyCredentialType="None" realm="" /> <message clientCredentialType="Windows" negotiateServiceCredential="true" algorithmSuite="Default" establishSecurityContext="true" /> </security> </binding> </wsHttpBinding> </bindings> At the client side I'm including the Service reference of the WCF-Service. It works great if I have limited functions say 90 Operation Contract in my IService but if add one more OperationContract than I'm unable to Update the Service reference nor i'm able to add that service reference. In this article it's mentioned that by changing those config files(i.e devenv.exe.config, WcfTestClient.exe.config and SvcUtil.exe.config) it will work but even including those bindings in those config files still that error pops up saying There was an error downloading 'http://10.0.3.112/MyService/Service1.svc/mex'. The request failed with HTTP status 400: Bad Request. Metadata contains a reference that cannot be resolved: 'http://10.0.3.112/MyService/Service1.svc/mex'. There is an error in XML document (1, 89549). The maximum nametable character count quota (16384) has been exceeded while reading XML data. The nametable is a data structure used to store strings encountered during XML processing - long XML documents with non-repeating element names, attribute names and attribute values may trigger this quota. This quota may be increased by changing the MaxNameTableCharCount property on the XmlDictionaryReaderQuotas object used when creating the XML reader. Line 1, position 89549. If the service is defined in the current solution, try building the solution and adding the service reference again. Any idea how to solve this????

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• Spring Security: session expiration without redirect to expired-url?

  - by Kdeveloper

  I'm using Spring Security 3.0.2 form based authentication. But I can't figure out how I can configure it so that when a session expires that the request is not redirect to an other page (expired-url) or displays a 'session expires' message. I don't want any redirect or messages, I want that a anonymous session is started just like when a user without a session enters the website. My current configuration: <http> <intercept-url pattern="/login.action*" filters="none"/> <intercept-url pattern="/admin/**" access="ROLE_ADMIN" /> <intercept-url pattern="/**" access="IS_AUTHENTICATED_ANONYMOUSLY"/> <form-login login-page="/login.action" authentication-failure-url="/login.action?error=failed" login-processing-url="/login-handler.action"/> <logout logout-url="/logoff-execute.action" logout-success-url="/logoff.action?done=1"/> <remember-me key="remember-me-security" services-ref="rememberMeServices"/> <session-management > <concurrency-control max-sessions="1" error-if-maximum-exceeded="false" expired-url="/login.action?error=expired.url"/> </session-management> </http>

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• XmlSerializer Deserialize failures

  - by smvlad

  I have wsdl from third party server. Method that i'm interested in returns XmlNode. My thought was wrap web methods and use XmlSerializer to return strongly typed objects. Returned xml looks like this (i removed soap headers): <Response xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:type="ResponseExt" xmlns="http://www.thirdparty.com/lr/"> <Code>0</Code> <Message>SUCCESS</Message> <SessionId>session_token</SessionId> </Response> Looked simple. Created a class: [XmlRoot("Response")] public class MyClass { public string Code {get; set;} public string Message {get; set;} public string SessionId {get; set;} } Processing time: //XmlNode node = xml from above XmlSerializer serializer = new XmlSerializer(typeof(MyClass)); XmlNodeReader reader = new XmlNodeReader(node); Myclass myclass = serializer.Deserialize(reader) as MyClass Last line is where it blows up with inner exception message: The specified type was not recognized: name='ResponseExt', namespace='http://www.thirdparty.com/lr/', at . I can't figure out how to make Serializer happy and what exactly these two mean xsi:type="ResponseExt" xmlns="http://www.thirdparty.com/lr/ As always any advice and pointer are appreciated

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• Ado.net dataservices BeginExecuteBatch call works on development fails on production server with Obj

  - by Mike Morley

  We have an ado.net dataservices 1.0 call that is being passed to a [WebGet] service operation as a batch through BeginExecuteBatch. Everything works perfectly on our development server - we have the project configured to use IIS instead of the cassini web server to make it as close to our production server as we can. When we publish to the production server, all the service operations work perfectly except the batch call, which fails with Object does not match target type. . I have not been able to find any cause for this. I can even run a single non-batch style GET operation against the [WebGet] service by copying the URL used in the batch and pasting it in a browser. I have not been able to find any information to help me solve this - any guidance would be most appreciated. Thanks, Mike M. Error message From Fiddler: HTTP/1.1 500 Internal Server Error Content-Type: application/xml DataServiceVersion: 1.0; An error occurred while processing this request. Object does not match target type. System.Reflection.TargetException at System.Reflection.RuntimeMethodInfo.CheckConsistency(Object target) at System.Reflection.RuntimeMethodInfo.Invoke(Object obj, BindingFlags invokeAttr, Binder binder, Object[] parameters, CultureInfo culture, Boolean skipVisibilityChecks) at System.Reflection.RuntimeMethodInfo.Invoke(Object obj, BindingFlags invokeAttr, Binder binder, Object[] parameters, CultureInfo culture) at System.Data.Services.RequestUriProcessor.CreateFirstSegment(IDataService service, String identifier, Boolean checkRights, String queryPortion, Boolean& crossReferencingUrl) at System.Data.Services.RequestUriProcessor.CreateSegments(String[] segments, IDataService service) at System.Data.Services.RequestUriProcessor.ProcessRequestUri(Uri absoluteRequestUri, IDataService service) at System.Data.Services.DataService`1.BatchDataService.HandleBatchContent(Stream responseStream)

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• Spring Security session-management setting and IllegalStateException

  - by JayL

  I'm trying to add <session-management> in my Spring Security namespace configuration so that I can provide a different message than the login page when the session times out. As soon as I add it to my configuration it starts throwing "IllegalStateException: Cannot create a session after the response has been committed" when I access the app. I'm using Spring Security 3 and Tomcat 6. Here's my configuration: <http> <intercept-url pattern="/go.htm" access="ROLE_RESPONDENT" /> <intercept-url pattern="/complete.htm" access="ROLE_RESPONDENT" /> <intercept-url pattern="/**" access="IS_AUTHENTICATED_ANONYMOUSLY" /> <form-login login-processing-url="/j_spring_security_check" login-page="/login.htm" authentication-failure-url="/login.htm?error=true" default-target-url="/go.htm" /> <anonymous/> <logout logout-success-url="/logout_message.htm"/> <session-management invalid-session-url="/login.htm" /> </http> Everything works great until I add in the <session-management> line. What am I missing?

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