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• Reconciling the Boy Scout Rule and Opportunistic Refactoring with code reviews

  - by t0x1n

  I am a great believer in the Boy Scout Rule: Always check a module in cleaner than when you checked it out." No matter who the original author was, what if we always made some effort, no matter how small, to improve the module. What would be the result? I think if we all followed that simple rule, we'd see the end of the relentless deterioration of our software systems. Instead, our systems would gradually get better and better as they evolved. We'd also see teams caring for the system as a whole, rather than just individuals caring for their own small little part. I am also a great believer in the related idea of Opportunistic Refactoring: Although there are places for some scheduled refactoring efforts, I prefer to encourage refactoring as an opportunistic activity, done whenever and wherever code needs to cleaned up - by whoever. What this means is that at any time someone sees some code that isn't as clear as it should be, they should take the opportunity to fix it right there and then - or at least within a few minutes Particularly note the following excerpt from the refactoring article: I'm wary of any development practices that cause friction for opportunistic refactoring ... My sense is that most teams don't do enough refactoring, so it's important to pay attention to anything that is discouraging people from doing it. To help flush this out be aware of any time you feel discouraged from doing a small refactoring, one that you're sure will only take a minute or two. Any such barrier is a smell that should prompt a conversation. So make a note of the discouragement and bring it up with the team. At the very least it should be discussed during your next retrospective. Where I work, there is one development practice that causes heavy friction - Code Review (CR). Whenever I change anything that's not in the scope of my "assignment" I'm being rebuked by my reviewers that I'm making the change harder to review. This is especially true when refactoring is involved, since it makes "line by line" diff comparison difficult. This approach is the standard here, which means opportunistic refactoring is seldom done, and only "planned" refactoring (which is usually too little, too late) takes place, if at all. I claim that the benefits are worth it, and that 3 reviewers will work a little harder (to actually understand the code before and after, rather than look at the narrow scope of which lines changed - the review itself would be better due to that alone) so that the next 100 developers reading and maintaining the code will benefit. When I present this argument my reviewers, they say they have no problem with my refactoring, as long as it's not in the same CR. However I claim this is a myth: (1) Most of the times you only realize what and how you want to refactor when you're in the midst of your assignment. As Martin Fowler puts it: As you add the functionality, you realize that some code you're adding contains some duplication with some existing code, so you need to refactor the existing code to clean things up... You may get something working, but realize that it would be better if the interaction with existing classes was changed. Take that opportunity to do that before you consider yourself done. (2) Nobody is going to look favorably at you releasing "refactoring" CRs you were not supposed to do. A CR has a certain overhead and your manager doesn't want you to "waste your time" on refactoring. When it's bundled with the change you're supposed to do, this issue is minimized. The issue is exacerbated by Resharper, as each new file I add to the change (and I can't know in advance exactly which files would end up changed) is usually littered with errors and suggestions - most of which are spot on and totally deserve fixing. The end result is that I see horrible code, and I just leave it there. Ironically, I feel that fixing such code not only will not improve my standings, but actually lower them and paint me as the "unfocused" guy who wastes time fixing things nobody cares about instead of doing his job. I feel bad about it because I truly despise bad code and can't stand watching it, let alone call it from my methods! Any thoughts on how I can remedy this situation ?

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• TiVo Follow-up&hellip;Training Opportunities

  - by MightyZot

  A few posts ago I talked about my experience with TiVo Customer Service. While I didn’t receive bad service per se, I felt like the reps could have communicated better. I made the argument that it should be just as easy to leave a company as it is to engage with a company, even though my intention is to remain a TiVo fan. I worked for DataStorm Technologies in the early 90s. I pointed out to another developer that we were leaving files behind in our installations. My opinion was that, if the customer is uninstalling our application, there should be no trace of it left after uninstall except for the customer’s data. He replied with, “screw ‘em. They’re leaving us. Why do we care if we left anything behind?” Wow. Surely there is a lot of arrogance in that statement. Think about this…how often do you change your services, devices, or whatever?  Personally, I change things up about once every two or three years. If I don’t change things up, I at least think about it. So, every two or three years there is an opportunity for you (as a vendor or business) to sell me something. (That opportunity actually exists all the time, because there are many of these two or three year periods overlapping.) Likewise, you have the opportunity to win back my business every two or three years as well. Customer service on exit is just as important as customer service during engagement because, every so often, you have another chance to gain back my loyalty. If you screw that up on exit, your chances are close to zero. In addition, you need to consider all of the potential or existing customers that are part of or affected by my social organizations. “Melissa” at TiVo gave me a call last week and set up some time to talk about my experience. We talked yesterday and she gave me a few moments to pontificate about my thoughts on the importance of a complete customer experience. She had listened to my customer support calls and agreed that I had made it clear that I intended to remain a TiVo customer even though suddenLink is handling my subscription. She said that suddenLink is a very important partner for them and, of course, they want to do everything they can to support TiVo / suddenLink customers.  “Melissa” also said that they had turned this experience into a training opportunity for the reps involved. I hope that is true, because that “programmer arrogance” that I mentioned above (which was somewhat pervasive back then) may be part of the reason why that company is no longer around. Good job “Melissa”!  And, like I said, I am still a TiVo fan. In fact, we love our new TiVo and many of the great new features. In addition, if you’re one of the two people that read these posts, please remember that these are just opinions. Your experiences may be, and likely will be, completely unique to you.

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• Book review (Book 6) - Wikinomics

  - by BuckWoody

  This is a continuation of the books I challenged myself to read to help my career - one a month, for year. You can read my first book review here. The book I chose for November 2011 was: Wikinomics: How Mass Collaboration Changes Everything, by Don Tapscott   Why I chose this Book: I’ve heard a lot about this book - was one of the “must read” kind of business books (many of which are very “fluffy”) and supposedly deals with collaborating using technology - so I want to see what it says about collaborative efforts and how I can leverage them. What I learned: I really disliked this book. I’ve never been a fan of the latest “business book”, and sadly that’s what this felt like to me. A “business book” is what I call a work that has a fairly simple concept to get across, and then proceeds to use various made-up terms, analogies and other mechanisms to fill hundreds of pages doing it. This perception is at my own – the book is pretty old, and these things go stale quickly. The author’s general point (at least what I took away from it) was: Open Source is good, proprietary is bad. Collaboration is the hallmark of successful companies. In my mind, you can save yourself the trouble of reading this work if you get these two concepts down. Don’t get me wrong – open source is awesome, and collaboration is a good thing, especially in places where it fits. But it’s not a panacea as the author seems to indicate. For instance, he continuously uses the example of MySpace to show a “2.0” company, which I think means that you can enter text as well as read it on a web page. All well and good. But we all know what happened to MySpace, and of course he missed the point entirely about this new web environment: low barriers to entry often mean low barriers to exit. And the open, collaborative company being the best model – well, I think we all know a certain computer company famous for phones and music that is arguably quite successful, and is probably one of the most closed, non-collaborative (at least with its customers) on the planet. So that sort of takes away that argument. The reality of business is far more complicated. Collaboration is an amazing tool, and should be leveraged heavily. However, at the end of the day, after you do your research you need to pick a strategy and stick with it. Asking thousands of people to assist you in building your product probably will not work well. Open Source is great – but some proprietary products are quite functional as well, have a long track record, are well supported, and will probably be upgraded. Everything has its place, so use what works where it is needed. There is no single answer, sadly. So did I waste my time reading the book? Did I make a bad choice? Not at all! Reading the opinions and thoughts of others is almost always useful, and it’s important to consider opinions other than your own. If nothing else, thinking through the process either convinces you that you are wrong, or helps you understand better why you are right.

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• JustMock is here !!

  - by mehfuzh

  As announced earlier by Hristo Kosev at Telerik blogs , we have started giving out JustMock builds from today. This is the first of early builds before the official Q2 release and we are pretty excited to get your feedbacks. Its pretty early to say anything on it. It actually depends on your feedback. To add few, with JustMock we tried to build a mocking tool with simple and intuitive syntax as possible excluding more and more noises and avoiding any smell that can be made to your code [We are still trying everyday] and we want to make the tool even better with your help. JustMock can be used to mock virtually anything. Moreover, we left an option open that it can be used to reduce / elevate the features  just though a single click. We tried to make a strong API and make stuffs fluent and guided as possible so that you never have the chance to get de-railed. Our syntax is AAA (Arrange – Act – Assert) , we don’t believe in Record – Reply model which some of the smarter mocking tools are planning to remove from their coming release or even don’t have [its always fun to lean from each other]. Overall more signals equals more complexity , reminds me of 37 signals :-). Currently, here are the things you can do with JustMock ( will cover more in-depth in coming days) Proxied mode Mock interfaces and class with virtuals Mock properties that includes indexers Set raise event for specific calls Use matchers to control mock arguments Assert specific occurrence of a mocked calls. Assert using matchers Do recursive mocks Do Sequential mocking ( same method with argument returns different values or perform different tasks) Do strict mocking (by default and i prefer loose , so that i can use it as stubs) Elevated mode Mock static calls Mock final class Mock sealed classes Mock Extension methods Partially mock a  class member directly using Mock.Arrange Mock MsCorlib (we will support more and more members in coming days) , currently we support FileInfo, File and DateTime. These are few, you need to take a look at the test project that is provided with the build to find more [Along with the document]. Also, one of feature that will i will be using it for my next OS projects is the ability to run it separately in  proxied mode which makes it easy to redistribute and do some personal development in a more DI model and my option to elevate as it go.   I’ve surely forgotten tons of other features to mention that i will cover time but  don’t for get the URL : www.telerik.com/justmock   Finally a little mock code:   var lvMock = Mock.Create<ILoveJustMock>();    // set your goal  Mock.Arrange(() => lvMock.Response(Arg.Any<string>())).Returns((int result) => result);    //perform  string ret =  lvMock.Echo("Yes");    Assert.Equal(ret, "Yes");  // make sure everything is fine  Mock.Assert(() => lvMock.Echo("Yes"), Occurs.Once());   Hope that helps to get started,  will cover if not :-).

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• Healthcare and Distributed Data Don't Mix

  - by [email protected]

  How many times have you heard the story?  Hard disk goes missing, USB thumb drive goes missing, laptop goes missing...Not a week goes by that we don't hear about our data going missing...  Healthcare data is a big one, but we hear about credit card data, pricing info, corporate intellectual property...  When I have spoken at Security and IT conferences part of my message is "Why do you give your users data to lose in the first place?"  I don't suggest they can't have access to it...in fact I work for the company that provides the premiere data security and desktop solutions that DO provide access.  Access isn't the issue.  'Keeping the data' is the issue.We are all human - we all make mistakes... I fault no one for having their car stolen or that they dropped a USB thumb drive. (well, except the thieves - I can certainly find some fault there)  Where I find fault is in policy (or lack thereof sometimes) that allows users to carry around private, and important, data with them.  Mr. Director of IT - It is your fault, not theirs.  Ms. CSO - Look in the mirror.It isn't like one can't find a network to access the data from.  You are on a network right now.  How many Wireless ones (wifi, mifi, cellular...) are there around you, right now?  Allowing employees to remove data from the confines of (wait for it... ) THE DATA CENTER is just plain indefensible when it isn't required.  The argument that the laptop had a password and the hard disk was encrypted is ridiculous.  An encrypted drive tells thieves that before they sell the stolen unit for $75, they should crack the encryption and ascertain what the REAL value of the laptop is... credit card info, Identity info, pricing lists, banking transactions... a veritable treasure trove of info people give away on an 'encrypted disk'.What started this latest rant on lack of data control was an article in Government Health IT that was forwarded to me by Denny Olson, an Oracle Principal Sales Consultant in Minnesota.  The full article is here, but the point was that a couple laptops went missing in a couple different cases, and.. well... no one knows where the data is, and yes - they were loaded with patient info.  What were you thinking?Obviously you can't steal data form a Sun Ray appliance... since it has no data, nor any storage to keep the data on, and Secure Global Desktop allows access from Macs, Linux and Windows client devices...  but in all cases, there is no keeping the data unless you explicitly allow for it in your policy.   Since you can get at the data securely from any network, why would you want to take personal responsibility for it?  Both Sun Rays and Secure Global Desktop are widely used in Healthcare... but clearly not widely enough.We need to do a better job of getting the message out -  Healthcare (or insert your business type here) and distributed data don't mix. Then add Hot Desking and 'follow me printing' and you have something that Clinicians (and CSOs) love.Thanks for putting up my blood pressure, Denny.

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• The enterprise vendor con - connecting SSD's using SATA 2 (3Gbits) thus limiting there performance

  - by tonyrogerson

  When comparing SSD against Hard drive performance it really makes me cross when folk think comparing an array of SSD running on 3GBits/sec to hard drives running on 6GBits/second is somehow valid. In a paper from DELL (http://www.dell.com/downloads/global/products/pvaul/en/PowerEdge-PowerVaultH800-CacheCade-final.pdf) on increasing database performance using the DELL PERC H800 with Solid State Drives they compare four SSD drives connected at 3Gbits/sec against ten 10Krpm drives connected at 6Gbits [Tony slaps forehead while shouting DOH!]. It is true in the case of hard drives it probably doesn’t make much difference 3Gbit or 6Gbit because SAS and SATA are both end to end protocols rather than shared bus architecture like SCSI, so the hard drive doesn’t share bandwidth and probably can’t get near the 600MiBytes/second throughput that 6Gbit gives unless you are doing contiguous reads, in my own tests on a single 15Krpm SAS disk using IOMeter (8 worker threads, queue depth of 16 with a stripe size of 64KiB, an 8KiB transfer size on a drive formatted with an allocation size of 8KiB for a 100% sequential read test) I only get 347MiBytes per second sustained throughput at an average latency of 2.87ms per IO equating to 44.5K IOps, ok, if that was 3GBits it would be less – around 280MiBytes per second, oh, but wait a minute [...fingers tap desk] You’ll struggle to find in the commodity space an SSD that doesn’t have the SATA 3 (6GBits) interface, SSD’s are fast not only low latency and high IOps but they also offer a very large sustained transfer rate, consider the OCZ Agility 3 it so happens that in my masters dissertation I did the same test but on a difference box, I got 374MiBytes per second at an average latency of 2.67ms per IO equating to 47.9K IOps – cost of an 240GB Agility 3 is £174.24 (http://www.scan.co.uk/products/240gb-ocz-agility-3-ssd-25-sata-6gb-s-sandforce-2281-read-525mb-s-write-500mb-s-85k-iops), but that same drive set in a box connected with SATA 2 (3Gbits) would only yield around 280MiBytes per second thus losing almost 100MiBytes per second throughput and a ton of IOps too. So why the hell are “enterprise” vendors still only connecting SSD’s at 3GBits? Well, my conspiracy states that they have no interest in you moving to SSD because they’ll lose so much money, the argument that they use SATA 2 doesn’t wash, SATA 3 has been out for some time now and all the commodity stuff you buy uses it now. Consider the cost, not in terms of price per GB but price per IOps, SSD absolutely thrash Hard Drives on that, it was true that the opposite was also true that Hard Drives thrashed SSD’s on price per GB, but is that true now, I’m not so sure – a 300GByte 2.5” 15Krpm SAS drive costs £329.76 ex VAT (http://www.scan.co.uk/products/300gb-seagate-st9300653ss-savvio-15k3-25-hdd-sas-6gb-s-15000rpm-64mb-cache-27ms) which equates to £1.09 per GB compared to a 480GB OCZ Agility 3 costing £422.10 ex VAT (http://www.scan.co.uk/products/480gb-ocz-agility-3-ssd-25-sata-6gb-s-sandforce-2281-read-525mb-s-write-410mb-s-30k-iops) which equates to £0.88 per GB. Ok, I compared an “enterprise” hard drive with a “commodity” SSD, ok, so things get a little more complicated here, most “enterprise” SSD’s are SLC and most commodity are MLC, SLC gives more performance and wear, I’ll talk about that another day. For now though, don’t get sucked in by vendor marketing, SATA 2 (3Gbit) just doesn’t cut it, SSD need 6Gbit to breath and even that SSD’s are pushing. Alas, SSD’s are connected using SATA so all the controllers I’ve seen thus far from HP and DELL only do SATA 2 – deliberate? Well, I’ll let you decide on that one.

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• Implementing features in an Entity System

  - by Bane

  After asking two questions on Entity Systems (1, 2), and reading some articles on them, I think that I understand them much better than before. But, I still have some uncertainties, and mainly they are about building a Particle Emitter, an Input system, and a Camera. I obviously still have some problems understanding Entity Systems, and they might apply to a whole other range of objects, but I chose these three because they are very different concepts and should cover a pretty big ground, and help me understand Entity Systems and how to handle problems like these myself, as they come along. I am building an engine in Javascript, and I've implemented most of the core features, which include: input handling, flexible animation system, particle emitter, math classes and functions, scene handling, a camera and a render, and a whole bunch of other things that engines usually support. Then, I read Byte56's answer that got me interested into making the engine into an Entity System one. It would still remain an HTML5 game engine with the basic Scene philosophy, but it should support dynamic creation of entities from components. These are some of the definitions from the previous questions, updated: An Entity is an identifier. It doesn't have any data, it's not an object, it's a simple id that represents an index in the Scene's list of all entities (which I actually plan to implement as a component matrix). A Component is a data holder, but with methods that can operate on that data. The best example is a Vector2D, or a "Position" component. It has data: x and y, but also some methods that make operating on the data a bit easier: add(), normalize(), and so on. A System is something that can operate on a set of entities that meet the certain requirements, usually they (the entities) need to have a specified (by the system itself) set of components to be operated upon. The system is the "logic" part, the "algorithm" part, all the functionality supplied by components is purely for easier data management. The problem that I have now is fitting my old engine concept into this new programming paradigm. Lets start with the simplest one, a Camera. The camera has a position property (Vector2D), a rotation property and some methods for centering it around a point. Each frame, it is fed to a renderer, along with a scene, and all the objects are translated according to it's position. Then the scene is rendered. How could I represent this kind of an object in an Entity System? Would the camera be an entity or simply a component? A combination (see my answer)? Another issues that is bothering me is implementing a Particle Emitter. For what exactly I mean by that, you can check out my video of it: http://youtu.be/BObargIMQsE. The problem I have with this is, again, what should be what. I'm pretty sure that particles themselves shouldn't be entities, as I want to support 10k+ of them, and creating that much entities would be a heavy blow on my performance, I believe. Or maybe not? Depends on the implementation, but anyone with experience: please, do answer. The last bit I wan't to talk about, which is also bugging me the most, is how input should be handled. In my current version of the engine, there is a class called Input. It's a handler that subscribes to browser's events, such as keypresses, and mouse position changes, and also it maintains an internal state. Then, the player class has a react() method, which accepts an input object as an argument. The advantage of this is that the input object could be serialized into JSON and then shared over the network, allowing for smooth multiplayer simulations. But how does this translate into an Entity System?

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• JMSContext, @JMSDestinationDefintion, DefaultJMSConnectionFactory with simplified JMS API: TOTD #213

  - by arungupta

  "What's New in JMS 2.0" Part 1 and Part 2 provide comprehensive introduction to new messaging features introduced in JMS 2.0. The biggest improvement in JMS 2.0 is introduction of the "new simplified API". This was explained in the Java EE 7 Launch Technical Keynote. You can watch a complete replay here. Sending and Receiving a JMS message using JMS 1.1 requires lot of boilerplate code, primarily because the API was designed 10+ years ago. Here is a code that shows how to send a message using JMS 1.1 API: @Statelesspublic class ClassicMessageSender { @Resource(lookup = "java:comp/DefaultJMSConnectionFactory") ConnectionFactory connectionFactory; @Resource(mappedName = "java:global/jms/myQueue") Queue demoQueue; public void sendMessage(String payload) { Connection connection = null; try { connection = connectionFactory.createConnection(); connection.start(); Session session = connection.createSession(false, Session.AUTO_ACKNOWLEDGE); MessageProducer messageProducer = session.createProducer(demoQueue); TextMessage textMessage = session.createTextMessage(payload); messageProducer.send(textMessage); } catch (JMSException ex) { ex.printStackTrace(); } finally { if (connection != null) { try { connection.close(); } catch (JMSException ex) { ex.printStackTrace(); } } } }} There are several issues with this code: A JMS ConnectionFactory needs to be created in a application server-specific way before this application can run. Application-specific destination needs to be created in an application server-specific way before this application can run. Several intermediate objects need to be created to honor the JMS 1.1 API, e.g. ConnectionFactory -> Connection -> Session -> MessageProducer -> TextMessage. Everything is a checked exception and so try/catch block must be specified. Connection need to be explicitly started and closed, and that bloats even the finally block. The new JMS 2.0 simplified API code looks like: @Statelesspublic class SimplifiedMessageSender { @Inject JMSContext context; @Resource(mappedName="java:global/jms/myQueue") Queue myQueue; public void sendMessage(String message) { context.createProducer().send(myQueue, message); }} The code is significantly improved from the previous version in the following ways: The JMSContext interface combines in a single object the functionality of both the Connection and the Session in the earlier JMS APIs.  You can obtain a JMSContext object by simply injecting it with the @Inject annotation.  No need to explicitly specify a ConnectionFactory. A default ConnectionFactory under the JNDI name of java:comp/DefaultJMSConnectionFactory is used if no explicit ConnectionFactory is specified. The destination can be easily created using newly introduced @JMSDestinationDefinition as: @JMSDestinationDefinition(name = "java:global/jms/myQueue",        interfaceName = "javax.jms.Queue") It can be specified on any Java EE component and the destination is created during deployment. JMSContext, Session, Connection, JMSProducer and JMSConsumer objects are now AutoCloseable. This means that these resources are automatically closed when they go out of scope. This also obviates the need to explicitly start the connection JMSException is now a runtime exception. Method chaining on JMSProducers allows to use builder patterns. No need to create separate Message object, you can specify the message body as an argument to the send() method instead. Want to try this code ? Download source code! Download Java EE 7 SDK and install. Start GlassFish: bin/asadmin start-domain Build the WAR (in the unzipped source code directory): mvn package Deploy the WAR: bin/asadmin deploy <source-code>/jms/target/jms-1.0-SNAPSHOT.war And access the application at http://localhost:8080/jms-1.0-SNAPSHOT/index.jsp to send and receive a message using classic and simplified API. A replay of JMS 2.0 session from Java EE 7 Launch Webinar provides complete details on what's new in this specification: Enjoy!

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• Subterranean IL: Custom modifiers

  - by Simon Cooper

  In IL, volatile is an instruction prefix used to set a memory barrier at that instruction. However, in C#, volatile is applied to a field to indicate that all accesses on that field should be prefixed with volatile. As I mentioned in my previous post, this means that the field definition needs to store this information somehow, as such a field could be accessed from another assembly. However, IL does not have a concept of a 'volatile field'. How is this information stored? Attributes The standard way of solving this is to apply a VolatileAttribute or similar to the field; this extra metadata notifies the C# compiler that all loads and stores to that field should use the volatile prefix. However, there is a problem with this approach, namely, the .NET C++ compiler. C++ allows methods to be overloaded using properties, like volatile or const, on the parameters; this is perfectly legal C++: public ref class VolatileMethods { void Method(int *i) {} void Method(volatile int *i) {} } If volatile was specified using a custom attribute, then the VolatileMethods class wouldn't be compilable to IL, as there is nothing to differentiate the two methods from each other. This is where custom modifiers come in. Custom modifiers Custom modifiers are similar to custom attributes, but instead of being applied to an IL element separately to its declaration, they are embedded within the field or parameter's type signature itself. The VolatileMethods class would be compiled to the following IL: .class public VolatileMethods { .method public instance void Method(int32* i) {} .method public instance void Method( int32 modreq( [mscorlib]System.Runtime.CompilerServices.IsVolatile)* i) {} } The modreq([mscorlib]System.Runtime.CompilerServices.IsVolatile) is the custom modifier. This adds a TypeDef or TypeRef token to the signature of the field or parameter, and even though they are mostly ignored by the CLR when it's executing the program, this allows methods and fields to be overloaded in ways that wouldn't be allowed using attributes. Because the modifiers are part of the signature, they need to be fully specified when calling such a method in IL: call instance void Method( int32 modreq([mscorlib]System.Runtime.CompilerServices.IsVolatile)*) There are two ways of applying modifiers; modreq specifies required modifiers (like IsVolatile), and modopt specifies optional modifiers that can be ignored by compilers (like IsLong or IsConst). The type specified as the modifier argument are simple placeholders; if you have a look at the definitions of IsVolatile and IsLong they are completely empty. They exist solely to be referenced by a modifier. Custom modifiers are used extensively by the C++ compiler to specify concepts that aren't expressible in IL, but still need to be taken into account when calling method overloads. C++ and C# That's all very well and good, but how does this affect C#? Well, the C++ compiler uses modreq(IsVolatile) to specify volatility on both method parameters and fields, as it would be slightly odd to have the same concept represented using a modifier or attribute depending on what it was applied to. Once you've compiled your C++ project, it can then be referenced and used from C#, so the C# compiler has to recognise the modreq(IsVolatile) custom modifier applied to fields, and vice versa. So, even though you can't overload fields or parameters with volatile using C#, volatile needs to be expressed using a custom modifier rather than an attribute to guarentee correct interoperability and behaviour with any C++ dlls that happen to come along. Next up: a closer look at attributes, and how certain attributes compile in unexpected ways.

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• Python Coding standards vs. productivity

  - by Shroatmeister

  I work for a large humanitarian organisation, on a project building software that could help save lives in emergencies by speeding up the distribution of food. Many NGOs desperately need our software and we are weeks behind schedule. One thing that worries me in this project is what I think is an excessive focus on coding standards. We write in python/django and use a version of PEP0008, with various modifications e.g. line lengths can go up to 160 chars and all lines should go that long if possible, no blank lines between imports, line wrapping rules that apply only to certain kinds of classes, lots of templates that we must use, even if they aren't the best way to solve a problem etc. etc. One core dev spent a week rewriting a major part of the system to meet the then new coding standards, throwing away several suites of tests in the process, as the rewrite meant they were 'invalid'. We spent two weeks rewriting all the functionality that was lost, and fixing bugs. He is the lead dev and his word carries weight, so he has convinced the project manager that these standards are necessary. The junior devs do as they are told. I sense that the project manager has a strong feeling of cognitive dissonance about all this but nevertheless agrees with it vehemently as he feels unsure what else to do. Today I got in serious trouble because I had forgotten to put some spaces after commas in a keyword argument. I was literally shouted at by two other devs and the project manager during a Skype call. Personally I think coding standards are important but also think that we are wasting a lot of time obsessing with them, and when I verbalized this it provoked rage. I'm seen as a troublemaker in the team, a team that is looking for scapegoats for its failings. Since the introduction of the coding standards, the team's productivity has measurably plummeted, however this only reinforces the obsession, i.e. the lead dev simply blames our non-adherence to standards for the lack of progress. He believes that we can't read each other's code if we don't adhere to the conventions. This is starting to turn sticky. Now I am trying to modify various scripts, autopep8, pep8ify and PythonTidy to try to match the conventions. We also run pep8 against source code but there are so many implicit amendments to our standard that it's hard to track them all. The lead dev simple picks faults that the pep8 script doesn't pick up and shouts at us in the next stand-up meeting. Every week there are new additions to the coding standards that force us to rewrite existing, working, tested code. Thank heavens we still have tests, (I reverted some commits and fixed a bunch of the ones he removed). All the while there is increasing pressure to meet the deadline. I believe a fundamental issue is that the lead dev and another core dev refuse to trust other developers to do their job. But how to deal with that? We can't do our job because we are too busy rewriting everything. I've never encountered this dynamic in a software engineering team. Am I wrong to question their adherence to coding standards? Has anyone else experienced a similar situation and how have they dealt with it successfully? (I'm not looking for a discussion just actual solutions people have found)

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• Integrated webcam in lenovo t410 not working with 12.04

  - by kristianp

  I have a Lenovo T410 with an inbuilt webcam and I haven't been able to get the webcam working. I tried skype, cheese, both just give me a black window. The microphone works fine with skype, by the way. Can anyone provide any clues please? The webcam is enabled in the bios, but there is no light indicating the webcam is on (not sure if there should be, though). I tried this on Kubuntu 11.10 and have upgraded to 12.04 with the same results. The Fn-F6 keyboard combination doens't seem to do anything either. EDIT: I got the webcam replaced, it looks like it was a hardware problem, because it works fine now. Thanks guys. $ ls /dev/v4l/* /dev/v4l/by-id: usb-Chicony_Electronics_Co.__Ltd._Integrated_Camera-video-index0 /dev/v4l/by-path: pci-0000:00:1a.0-usb-0:1.6:1.0-video-index0 And lsusb: $ lsusb Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub Bus 002 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub Bus 001 Device 002: ID 8087:0020 Intel Corp. Integrated Rate Matching Hub Bus 002 Device 002: ID 8087:0020 Intel Corp. Integrated Rate Matching Hub Bus 001 Device 003: ID 147e:2016 Upek Biometric Touchchip/Touchstrip Fingerprint Sensor Bus 001 Device 004: ID 0a5c:217f Broadcom Corp. Bluetooth Controller Bus 001 Device 005: ID 17ef:480f Lenovo Integrated Webcam [R5U877] Bus 002 Device 003: ID 05c6:9204 Qualcomm, Inc. Bus 002 Device 004: ID 17ef:1003 Lenovo Integrated Smart Card Reader Here is the output from guvcview, minus lots of lines describing the available capture formats. It says "unable to start with minimum setup. Please reconnect your camera.". guvcview 1.5.3 ALSA lib pcm_dmix.c:1018:(snd_pcm_dmix_open) unable to open slave ALSA lib pcm.c:2217:(snd_pcm_open_noupdate) Unknown PCM cards.pcm.rear ALSA lib pcm.c:2217:(snd_pcm_open_noupdate) Unknown PCM cards.pcm.center_lfe ALSA lib pcm.c:2217:(snd_pcm_open_noupdate) Unknown PCM cards.pcm.side ALSA lib audio/pcm_bluetooth.c:1614:(audioservice_expect) BT_GET_CAPABILITIES failed : Input/output error(5) ALSA lib audio/pcm_bluetooth.c:1614:(audioservice_expect) BT_GET_CAPABILITIES failed : Input/output error(5) ALSA lib audio/pcm_bluetooth.c:1614:(audioservice_expect) BT_GET_CAPABILITIES failed : Input/output error(5) ALSA lib audio/pcm_bluetooth.c:1614:(audioservice_expect) BT_GET_CAPABILITIES failed : Input/output error(5) ALSA lib pcm_dmix.c:957:(snd_pcm_dmix_open) The dmix plugin supports only playback stream ALSA lib pcm_dmix.c:1018:(snd_pcm_dmix_open) unable to open slave Cannot connect to server socket err = No such file or directory Cannot connect to server socket jack server is not running or cannot be started video device: /dev/video0 Init. Integrated Camera (location: usb-0000:00:1a.0-1.6) { pixelformat = 'YUYV', description = 'YUV 4:2:2 (YUYV)' } { discrete: width = 640, height = 480 } Time interval between frame: 1/30, .... { discrete: width = 1600, height = 1200 } Time interval between frame: 1/15, vid:17ef pid:480f driver:uvcvideo checking format: 1196444237 libv4l2: error setting pixformat: Device or resource busy VIDIOC_S_FORMAT - Unable to set format: Device or resource busy Init v4L2 failed !! Init video returned -2 trying minimum setup ... video device: /dev/video0 Init. Integrated Camera (location: usb-0000:00:1a.0-1.6) { pixelformat = 'YUYV', description = 'YUV 4:2:2 (YUYV)' } { discrete: width = 640, height = 480 } .... vid:17ef pid:480f driver:uvcvideo checking format: 1448695129 libv4l2: error setting pixformat: Device or resource busy VIDIOC_S_FORMAT - Unable to set format: Device or resource busy Init v4L2 failed !! ERROR: Minimum Setup Failed. Exiting... VIDIOC_REQBUFS - Failed to delete buffers: Invalid argument (errno 22) cleaned allocations - 100% Closing portaudio ...OK Terminated.

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• Code Contracts: validating arrays and collections

  - by DigiMortal

  Validating collections before using them is very common task when we use built-in generic types for our collections. In this posting I will show you how to validate collections using code contracts. It is cool how much awful looking code you can avoid using code contracts. Failing code Let’s suppose we have method that calculates sum of all invoices in collection. We have class Invoice and one of properties it has is Sum. I don’t introduce here any complex calculations on invoices because we have another problem to solve in this topic. Here is our code. public static decimal CalculateTotal(IList<Invoice> invoices) {     var sum = invoices.Sum(p => p.Sum);     return sum; } This method is very simple but it fails when invoices list contains at least one null. Of course, we can test if invoice is null but having nulls in lists like this is not good idea – it opens green way for different coding bugs in system. Our goal is to react to bugs ASAP at the nearest place they occur. There is one more way how to make our method fail. It happens when invoices is null. I thing it is also one common bugs during development and it even happens in production environments under some conditions that are usually hardly met. Now let’s protect our little calculation method with code contracts. We need two contracts: invoices cannot be null invoices cannot contain any nulls Our first contract is easy but how to write the second one? Solution: Contract.ForAll Preconditions in code are checked using Contract.Ensures method. This method takes boolean value as argument that sais if contract holds or not. There is also method Contract.ForAll that takes collection and predicate that must hold for that collection. Nice thing is ForAll returns boolean. So, we have very simple solution. public static decimal CalculateTotal(IList<Invoice> invoices) {     Contract.Requires(invoices != null);     Contract.Requires(Contract.ForAll<Invoice>(invoices, p => p != null));       var sum = invoices.Sum(p => p.Sum);     return sum; } And here are some lines of code you can use to test the contracts quickly. var invoices = new List<Invoice>(); invoices.Add(new Invoice()); invoices.Add(null); invoices.Add(new Invoice()); //CalculateTotal(null); CalculateTotal(invoices); If your code is covered with unit tests then I suggest you to write tests to check that these contracts hold for every code run. Conclusion Although it seemed at first place that checking all elements in collection may end up with for-loops that does not look so nice we were able to solve our problem nicely. ForAll method of contract class offered us simple mechanism to check collections and it does it smoothly the code-contracts-way. P.S. I suggest you also read devlicio.us blog posting Validating Collections with Code Contracts by Derik Whittaker.

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• Thoughts on C# Extension Methods

  - by Damon

  I'm not a huge fan of extension methods.  When they first came out, I remember seeing a method on an object that was fairly useful, but when I went to use it another piece of code that method wasn't available.  Turns out it was an extension method and I hadn't included the appropriate assembly and imports statement in my code to use it.  I remember being a bit confused at first about how the heck that could happen (hey, extension methods were new, cut me some slack) and it took a bit of time to track down exactly what it was that I needed to include to get that method back.  I just imagined a new developer trying to figure out why a method was missing and fruitlessly searching on MSDN for a method that didn't exist and it just didn't sit well with me. I am of the opinion that if you have an object, then you shouldn't have to include additional assemblies to get additional instance level methods out of that object.  That opinion applies to namespaces as well - I do not like it when the contents of a namespace are split out into multiple assemblies.  I prefer to have static utility classes instead of extension methods to keep things nicely packaged into a cohesive unit.  It also makes it abundantly clear where utility methods are used in code.  I will concede, however, that it can make code a bit more verbose and lengthy.  There is always a trade-off. Some people harp on extension methods because it breaks the tenants of object oriented development and allows you to add methods to sealed classes.  Whatever.  Extension methods are just utility methods that you can tack onto an object after the fact.  Extension methods do not give you any more access to an object than the developer of that object allows, so I say that those who cry OO foul on extension methods really don't have much of an argument on which to stand.  In fact, I have to concede that my dislike of them is really more about style than anything of great substance. One interesting thing that I found regarding extension methods is that you can call them on null objects. Take a look at this extension method: namespace ExtensionMethods {   public static class StringUtility   {     public static int WordCount(this string str)     {       if(str == null) return 0;       return str.Split(new char[] { ' ', '.', '?' },         StringSplitOptions.RemoveEmptyEntries).Length;     }   }   } Notice that the extension method checks to see if the incoming string parameter is null.  I was worried that the runtime would perform a check on the object instance to make sure it was not null before calling an extension method, but that is apparently not the case.  So, if you call the following code it runs just fine. string s = null; int words = s.WordCount(); I am a big fan of things working, but this seems to go against everything I've come to know about instance level methods.  However, an extension method is really a static method masquerading as an instance-level method, so I suppose it would be far more frustrating if it failed since there is really no reason it shouldn't succeed. Although I'm not a fan of extension methods, I will say that if you ever find yourself at an impasse with a die-hard fan of either the utility class or extension method approach, then there is a common ground.  Extension methods are defined in static classes, and you call them from those static classes as well as directly from the objects they extend.  So if you build your utility classes using extension methods, then you can have it your way and they can have it theirs. 

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• Attachments in Oracle BPM 11g – Create a BPM Process Instance by passing an Attachment

  - by Venugopal Mangipudi

  Problem Statement: On a recent engagement I had  a requirement where we needed to create BPM instances using a message start event. The challenge was that the instance needed to be created after polling a file location and attaching the picked up file (pdf) as an attachment to the instance. Proposed Solution: I was contemplating using process API to accomplish this,but came up with a solution which involves a BPEL process to pickup the file and send a notification to the BPM process by passing the attachment as a payload. The following are some of the brief steps that were used to build the solution: BPM Process to receive an attachment as part of the payload: The BPM Process is a very simple process which has a Message Start event that accepts the attachment as an argument and a Simple User Task that the user can use to view the attachment (as part of the OOTB attachment panel). The Input payload is based on AttachmentPayload.xsd.  The 3 key elements of the the payload are: <xsd:element name="filename" type="xsd:string"/> <xsd:element name="mimetype" type="xsd:string"/> <xsd:element name="content" type="xsd:base64Binary"/> A screenshot of the Human task data assignment that need to performed to attach the file is provided here. Once the process and the UI project (default generated UI) are deployed to the SOA server, copy the wsdl location of the process service (from EM). This WSDL would be used in the BPEL project to create the Instances in the BPM process after a file is polled. BPEL Process to Poll for File and create instances in the BPM process: For the BPEL process a File adapter was configured as a Read service (File Streaming option and keeping the Schema as Opaque). Once a location and the file pattern to poll are provided the Readservice Partner Link was wired to Invoke the BPEL Process. Also, using the BPM Process WSDL, we can create the Webservice reference and can invoke the start operation. Before we do the assignment for the Invoke operation, a global variable should be created to hold the value of the fileName of the file. The mapping to the global variable can be done on the Receive activity properties (jca.file.FileName).  So for the assign operation before we invoke the BPM process service, we can get the content of the file from the receive input variable and the fileName from the jca.file.FileName property. The mimetype needs to be hard coded to the mime-type of the file: application/pdf (I am still researching ways to derive the mime type as it is not available as part of the jca.file properties).  The screenshot of the BPEL process can be found here and the Assign activity can be found here. The project source can be found at the following location. A sample pdf file to test the project and a screenshot of the BPM Human task screen after the successful creation of the instance can be found here. References: [1] https://blogs.oracle.com/fmwinaction/entry/oracle_bpm_adding_an_attachment

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• How to run RCU from the command line

  - by Kevin Smith

  When I was trying to figure out how to run RCU on 64-bit Linux I found this post. It shows how to run RCU from the command line. It didn't actually work for me, so you can see my post on how to run RCU on 64-bit Linux. But, seeing how to run RCU from the command got me started thinking about running RCU from the command line to create the schema for WebCenter Content. That post got me part of the way there since it shows how run RCU silently from the command line, but to do this you need to know the name of the RCU component for WebCenter Content. I poked around in the RCU files and found the component name for WCC is CONTENTSERVER11. There is a contentserver11 directory in rcuHome/rcu/integration and when you look at the contentserver11.xml file you will see <RepositoryConfig COMP_ID="CONTENTSERVER11"> With the component name for WCC in hand I was able to use this command line to run RCU and create the schema for WCC. .../rcuHome/bin/rcu -silent -createRepository -databaseType ORACLE -connectString localhost:1521:orcl1 -dbUser sys -dbRole sysdba -schemaPrefix TEST -component CONTENTSERVER11 -f <rcu_passwords.txt To make the silent part work and not have it prompt you for the passwords needed (sys password and password for each schema) you use the -f option and specify a file containing the passwords, one per line, in the order the components are listed on the -component argument. Here is the output from rcu when I ran the above command. Processing command line ....Repository Creation Utility - Checking PrerequisitesChecking Global PrerequisitesRepository Creation Utility - Checking PrerequisitesChecking Component PrerequisitesRepository Creation Utility - Creating TablespacesValidating and Creating TablespacesRepository Creation Utility - CreateRepository Create in progress.Percent Complete: 0...Percent Complete: 100Repository Creation Utility: Create - Completion SummaryDatabase details:Host Name              : localhostPort                   : 1521Service Name           : ORCL1Connected As           : sysPrefix for (prefixable) Schema Owners : TESTRCU Logfile            : /u01/app/oracle/logdir.2012-09-26_07-53/rcu.logComponent schemas created:Component                            Status  LogfileOracle Content Server 11g - Complete Success /u01/app/oracle/logdir.2012-09-26_07-53/contentserver11.logRepository Creation Utility - Create : Operation Completed This works fine if you want to use the default tablespace sizes and options, but there does not seem to be a way to specify the tablespace options on the command line. You can specify the name of the tablespace and temp tablespace, but they must already exist in the database before running RCU. I guess you can always create the tablespaces first using your desired sizes and options and then run RCU and specify the tablespaces you created. When looking up the command line options in the RCU doc I found it has the list of components for each product that it supports. See Appendix B in the RCU User's Guide.

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• Sneak Peak: Social Developer Program at JavaOne

  - by Mike Stiles

  By guest blogger Roland Smart We're just days away from what is gunning to be the most exciting installment of OpenWorld to date, so how about an exciting sneak peak at the very first Social Developer Program? If your first thought is, "What's a social developer?" you're not alone. It’s an emerging term and one we think will gain prominence as social experiences become more prevalent in enterprise applications. For those who keep an eye on the ever-evolving Facebook platform, you'll recall that they recently rebranded their PDC (preferred developer consultant) group as the PMD (preferred marketing developer), signaling the importance of development resources inside the marketing organization to unlock the potential of social. The marketing developer they're referring to could be considered a social developer in a broader context. While it's true social has really blossomed in the marketing context and CMOs are winning more and more technical resources, social is starting to work its way more deeply into the enterprise with the help of developers that work outside marketing. Developers, like the rest of us, have fallen in "like" with social functionality and are starting to imagine how social can transform enterprise applications in the way it has consumer-facing experiences. The thesis of my presentation is that social developers will take many pages from the marketing playbook as they apply social inside the enterprise. To support this argument, lets walk through a range of enterprise applications and explore how consumer-facing social experiences might be interpreted in this context. Here's one example of how a social experience could be integrated into a sales enablement application. As a marketer, I spend a great deal of time collaborating with my sales colleagues, so I have good insight into their working process. While at Involver, we grew our sales team quickly, and it became evident some of our processes broke with scale. For example, we used to have weekly team meetings at which we'd discuss what was working and what wasn't from a messaging perspective. One aspect of these sessions focused on "objections" and "responses," where the salespeople would walk through common objections to purchasing and share appropriate responses. We tried to map each context to best answers and we'd capture these on a wiki page. As our team grew, however, participation at scale just wasn't tenable, and our wiki pages quickly lost their freshness. Imagine giving salespeople a place where they could submit common objections and responses for their colleagues to see, sort, comment on, and vote on. What you'd get is an up-to-date and relevant repository of information. And, if you supported an application like this with a social graph, it would be possible to make good recommendations to individual sales people about the objections they'd likely hear based on vertical, product, region or other graph data. Taking it even further, you could build in a badging/game element to reward those salespeople who participate the most. Both these examples are based on proven models at work inside consumer-facing applications. If you want to learn about how HR, Operations, Product Development and Customer Support can leverage social experiences, you’re welcome to join us at JavaOne or join our Social Developer Community to find some of the presentations after OpenWorld.

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• Thoughts on my new template language/HTML generator?

  - by Ralph

  I guess I should have pre-faced this with: Yes, I know there is no need for a new templating language, but I want to make a new one anyway, because I'm a fool. That aside, how can I improve my language: Let's start with an example: using "html5" using "extratags" html { head { title "Ordering Notice" jsinclude "jquery.js" } body { h1 "Ordering Notice" p "Dear @name," p "Thanks for placing your order with @company. It's scheduled to ship on {@ship_date|dateformat}." p "Here are the items you've ordered:" table { tr { th "name" th "price" } for(@item in @item_list) { tr { td @item.name td @item.price } } } if(@ordered_warranty) p "Your warranty information will be included in the packaging." p(class="footer") { "Sincerely," br @company } } } The "using" keyword indicates which tags to use. "html5" might include all the html5 standard tags, but your tags names wouldn't have to be based on their HTML counter-parts at all if you didn't want to. The "extratags" library for example might add an extra tag, called "jsinclude" which gets replaced with something like <script type="text/javascript" src="@content"></script> Tags can be optionally be followed by an opening brace. They will automatically be closed at the closing brace. If no brace is used, they will be closed after taking one element. Variables are prefixed with the @ symbol. They may be used inside double-quoted strings. I think I'll use single-quotes to indicate "no variable substitution" like PHP does. Filter functions can be applied to variables like @variable|filter. Arguments can be passed to the filter @variable|filter:@arg1,arg2="y" Attributes can be passed to tags by including them in (), like p(class="classname"). You will also be able to include partial templates like: for(@item in @item_list) include("item_partial", item=@item) Something like that I'm thinking. The first argument will be the name of the template file, and subsequent ones will be named arguments where @item gets the variable name "item" inside that template. I also want to have a collection version like RoR has, so you don't even have to write the loop. Thoughts on this and exact syntax would be helpful :) Some questions: Which symbol should I use to prefix variables? @ (like Razor), $ (like PHP), or something else? Should the @ symbol be necessary in "for" and "if" statements? It's kind of implied that those are variables. Tags and controls (like if,for) presently have the exact same syntax. Should I do something to differentiate the two? If so, what? This would make it more clear that the "tag" isn't behaving like just a normal tag that will get replaced with content, but controls the flow. Also, it would allow name-reuse. Do you like the attribute syntax? (round brackets) How should I do template inheritance/layouts? In Django, the first line of the file has to include the layout file, and then you delimit blocks of code which get stuffed into that layout. In CakePHP, it's kind of backwards, you specify the layout in the controller.view function, the layout gets a special $content_for_layout variable, and then the entire template gets stuffed into that, and you don't need to delimit any blocks of code. I guess Django's is a little more powerful because you can have multiple code blocks, but it makes your templates more verbose... trying to decide what approach to take Filtered variables inside quotes: "xxx {@var|filter} yyy" "xxx @{var|filter} yyy" "xxx @var|filter yyy" i.e, @ inside, @ outside, or no braces at all. I think no-braces might cause problems, especially when you try adding arguments, like @var|filter:arg="x", then the quotes would get confused. But perhaps a braceless version could work for when there are no quotes...? Still, which option for braces, first or second? I think the first one might be better because then we're consistent... the @ is always nudged up against the variable. I'll add more questions in a few minutes, once I get some feedback.

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• Swap not available on System Monitor

  - by Zaki

  I had a swap partition of 1GB (RAM 1GB, Ubuntu 12.04 lts). Now swap is not shown on System Monitor neither can I hibernate my pc (sudo pm-hibernate). blkid output: /dev/sda1: UUID="B8B4FBB1B4FB706C" TYPE="ntfs" /dev/sda2: UUID="2ea7d608-2d89-4e41-9436-d05cb3ce8871" TYPE="swap" /dev/sda3: UUID="3219d03a-67e4-454b-8ce7-a27831846e35" TYPE="ext4" /dev/sda5: LABEL="Softwares" UUID="AC1CC3301CC2F47C" TYPE="ntfs" /dev/sda6: LABEL="Education" UUID="1E103E6C103E4B53" TYPE="ntfs" /dev/sda7: LABEL="Recreation" UUID="2CC8D181C8D149AA" TYPE="ntfs" /dev/sda8: LABEL="Miscellaneous" UUID="0274D6B174D6A727" TYPE="ntfs" /etc/fstab # <file system> <mount point> <type> <options> <dump> <pass> proc /proc proc nodev,noexec,nosuid 0 0 # / was on /dev/sda6 during installation UUID=3219d03a-67e4-454b-8ce7-a27831846e35 / ext4 errors=remount-ro 0 1 # swap was on /dev/sda5 during installation UUID=2ea7d608-2d89-4e41-9436-d05cb3ce8871 none swap sw 0 0 free -m total used free shared buffers cached Mem: 991 867 123 0 27 418 -/+ buffers/cache: 421 569 Swap: 0 0 0 cat /proc/swaps Filename Type Size Used Priority fdisk -l Disk /dev/sda: 160.0 GB, 160041885696 bytes 255 heads, 63 sectors/track, 19457 cylinders, total 312581808 sectors Units = sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0x9f369f36 Device Boot Start End Blocks Id System /dev/sda1 * 63 31471334 15735636 7 HPFS/NTFS/exFAT /dev/sda2 31471616 33470447 999416 82 Linux swap / Solaris /dev/sda3 33472512 62539775 14533632 83 Linux /dev/sda4 62541045 312592769 125025862+ f W95 Ext'd (LBA) /dev/sda5 62541108 125066024 31262458+ 7 HPFS/NTFS/exFAT /dev/sda6 125066088 187591004 31262458+ 7 HPFS/NTFS/exFAT /dev/sda7 187591068 250115984 31262458+ 7 HPFS/NTFS/exFAT /dev/sda8 250116048 312576704 31230328+ 7 HPFS/NTFS/exFAT swapon --all swapon: /dev/sda2: swapon failed: Invalid argument dmesg | grep -A 5 -B 5 -i swap [ 9.487404] EXT4-fs (sda3): ext4_orphan_cleanup: deleting unreferenced inode 131645 [ 9.487413] EXT4-fs (sda3): ext4_orphan_cleanup: deleting unreferenced inode 131330 [ 9.487418] EXT4-fs (sda3): 16 orphan inodes deleted [ 9.487420] EXT4-fs (sda3): recovery complete [ 9.578600] EXT4-fs (sda3): mounted filesystem with ordered data mode. Opts: (null) [ 20.580539] Swap area shorter than signature indicates [ 20.588363] IPv6: ADDRCONF(NETDEV_UP): eth0: link is not ready [ 20.619443] udevd[330]: starting version 175 [ 20.649959] lp: driver loaded but no devices found [ 20.662972] [drm] Initialized drm 1.1.0 20060810 [ 20.675515] i915 0000:00:02.0: setting latency timer to 64 -- [ 72.288573] PM: thaw of drv:sr dev:3:0:0:0 complete after 178.143 msecs [ 72.288578] PM: thaw of drv:scsi_device dev:3:0:0:0 complete after 178.136 msecs [ 72.299677] PM: thaw of drv:scsi_device dev:2:0:0:0 complete after 189.270 msecs [ 72.309473] PM: thaw of devices complete after 202.763 msecs [ 72.309668] PM: writing image. [ 72.309670] PM: Cannot find swap device, try swapon -a. [ 72.309699] PM: Cannot get swap writer [ 72.329896] Restarting tasks ... done. [ 72.331777] PM: Basic memory bitmaps freed [ 72.331792] video LNXVIDEO:00: Restoring backlight state [ 72.420048] option1 ttyUSB0: option_instat_callback: error -84 [ 72.804047] option1 ttyUSB0: option_instat_callback: error -84 -- [ 145.960625] sd 7:0:0:0: Attached scsi generic sg2 type 0 [ 145.972036] sd 7:0:0:0: [sdb] Attached SCSI removable disk [ 172.430508] PPP BSD Compression module registered [ 172.455583] PPP Deflate Compression module registered [ 332.260789] type=1400 audit(1381814763.342:27): apparmor="DENIED" operation="capable" parent=1 profile="/usr/sbin/cupsd" pid=636 comm="cupsd" pid=636 comm="cupsd" capability=36 capname="block_suspend" [ 1913.030998] Swap area shorter than signature indicates [ 2022.530155] type=1400 audit(1381816453.610:28): apparmor="DENIED" operation="capable" parent=1 profile="/usr/sbin/cupsd" pid=636 comm="cupsd" pid=636 comm="cupsd" capability=36 capname="block_suspend" [ 4062.729509] Swap area shorter than signature indicates Please help. Thanks in advance. df -h Filesystem Size Used Avail Use% Mounted on /dev/sda3 14G 6.1G 7.0G 47% / udev 488M 4.0K 488M 1% /dev tmpfs 199M 868K 198M 1% /run none 5.0M 4.0K 5.0M 1% /run/lock none 496M 224K 496M 1% /run/shm

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• Planning development when academic research is involved

  - by Another Anonymous User

  Dear fellow programmers, how do you do "software planning" when academic research is involved? And, on a side note, how do you convince your boss that writing software is not like building a house and it's more like writing a novel? The gory details are below. I am in charge of a small dev team working in a research lab. We started developing a software with the purpose of going public one day (i.e. sell and make money off that). Such software depends on, amongst other things, at least two independent research lines: that is, there are at least two Ph.D. candidates that will, hopefully, one day come out with a working implementation of what we need. The main software depends also on other, more concrete resources that we as developers can take care of: graphics rendering, soft bodies deformation, etc. My boss asked me to write the specifications, requirements AND a bloody GANTT chart of the entire project. Faced with the fact that I don't have a clue about the research part, and that such research is fundamental for the software, he said "make assumptions." For the clarity of the argument, he is a professor whose Ph.D. students should come up with the research we need. And he comes from a strictly engineering background: plan everything first, write down specifications and only then write down code that "it's the last part". What I am doing now: I broke down the product in features; each 'feature' is, de facto, a separate product; Each feature is built on top of the previous one; Once a feature (A) has a working prototype the team can start working on the next feature (B), while QA for is being done for A (if money allows, more people can be brought in, etc.); Features that depend on research will come last: by then, hopefully, the research part will be completed (when is still a big question) ; Also, I set the team to use SCRUM for the development of 'version 1.0', due in a few months. This deadline could be set based on reasonable assumptions: we listed all required features, we counted our availability, and we gave a reasonable estimate. So my questions, again, are: How do I make my boss happy while at the same time get something out the door? How do I write specifications for something we -the developers- have no clue whether it's possible to do or not? (We still haven't decided which libraries to use for some tasks; we'll do so when we'll need to) How do I get the requirements for that, given that there are yet no clients nor investors, just lots of interests and promises? How do I get peace in the world? I am sure at least one of my questions will be answered :) ps: I am writing this anonymously since a potential investor might backfire if this is discovered. Hope you'll understand. However I must say I do not like this mentality of 'hiding the truth': this program will likely benefit many, and not being able to talk openly about this (with my name and my reputation attached) feels like censorship. But alas, I care more about your suggestions now.

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• Sprinkle Some Magik on that Java Virtual Machine

  - by Jim Connors

  GE Energy, through its Smallworld subsidiary, has been providing geospatial software solutions to the utility and telco markets for over 20 years.  One of the fundamental building blocks of their technology is a dynamically-typed object oriented programming language called Magik.  Like Java, Magik source code is compiled down to bytecodes that run on a virtual machine -- in this case the Magik Virtual Machine. Throughout the years, GE has invested considerable engineering talent in the support and maintenance of this virtual machine.  At the same time vast energy and resources have been invested in the Java Virtual Machine. The question for GE has been whether to continue to make that investment on its own or to leverage massive effort provided by the Java community? Utilizing the Java Virtual Machine instead of maintaining its own virtual machine would give GE more opportunity to focus on application solutions.   At last count, there are dozens, perhaps hundreds of examples of programming languages that have been hosted atop the Java Virtual Machine.  Prior to the release of Java 7, that effort, although certainly possible, was generally less than optimal for languages like Magik because of its dynamic nature.  Java, as a statically typed language had little use for this capability.  In the quest to be a more universal virtual machine, Java 7, via JSR-292, introduced a new bytecode called invokedynamic.  In short, invokedynamic affords a more flexible method call mechanism needed by dynamic languages like Magik. With this new capability GE Energy has succeeded in hosting their Magik environment on top of the Java Virtual Machine.  So you may ask, why would GE wish to do such a thing?  The benefits are many: Competitors to GE Energy claimed that the Magik environment was proprietary.  By utilizing the Java Virtual Machine, that argument gets put to bed.  JVM development is done in open source, where contributions are made world-wide by all types of organizations and individuals. The unprecedented wealth of class libraries and applications written for the Java platform are now opened up to Magik/JVM platform as first class citizens. In addition, the Magik/JVM solution vastly increases the developer pool to include the 9 million Java developers -- the largest developer community on the planet. Applications running on the JVM showed substantial performance gains, in some cases as much as a 5x speed up over the original Magik platform. Legacy Magik applications can still run on the original platform.  They can be seamlessly migrated to run on the JVM by simply recompiling the source code. GE can now leverage the huge Java community.  Undeniably the best virtual machine ever created, hundreds if not thousands of world class developers continually improve, poke, prod and scrutinize all aspects of the Java platform.  As enhancements are made, GE automatically gains access to these. As Magik has little in the way of support for multi-threading, GE will benefit from current and future Java offerings (e.g. lambda expressions) that aim to further facilitate multi-core/multi-threaded application development. As the JVM is available for many more platforms, it broadens the reach of Magik, including the potential to run on a class devices never envisioned just a few short years ago.  For example, Java SE compatible runtime environments are available for popular embedded ARM/Intel/PowerPC configurations that could theoretically host this software too. As compared to other JVM language projects, the Magik integration differs in that it represents a serious commercial entity betting a sizable part of its business on the success of this effort.  Expect to see announcements not only from General Electric, but other organizations as they realize the benefits of utilizing the Java Virtual Machine.

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• Friday Tips #3

  - by Chris Kawalek

  Even though yesterday was Thanksgiving here in the US, we still have a Friday tip for those of you around your computers today. In fact, we have two! The first one came in last week via our #AskOracleVirtualization Twitter hashtag. The tweet has disappeared into the ether now, but we remember the gist, so here it is: Question: Will there be an Oracle Virtual Desktop Client for Android? Answer by our desktop virtualization product development team: We are looking at Android as a supported platform for future releases. Question: How can I make a Sun Ray Client automatically connect to a virtual machine? Answer by Rick Butland, Principal Sales Consultant, Oracle Desktop Virtualization: Someone recently asked how they can assign VM’s to specific Sun Ray Desktop Units (“DTU’s”) without any user interfaction being required, without the “Desktop Selector” being displayed, or any User Directory.  That is, they wanted each Sun Ray to power on and immediately connect to a pre-assigned Solaris VM.   This can be achieved by using “tokens” for user assignment – that is, the tokens found on Smart Cards, DTU’s, or OVDC clients can be used in place of user credentials.  Note, however, that mixing “token-only” assignments and “User Directories” in the same VDI Center won’t work.   Much of this procedure is covered in the documentation, particularly here. But it can useful to have everything in one place, “cookbook-style”:  1. Create the “token-only” directory type: From the VDI administration interface, select:  “Settings”, “Company”, “New”, select the “None” radio button, and click “Next.” Enter a name for the new “Company”, and click “Next”, then “Finish.” 2. Create Desktop Providers, Pools, and VM’s as appropriate. 3. Access the Sun Ray administration interface at http://servername:1660 and login using “root” credentials, and access the token-id’s you wish to use for assignment.  If you’re using DTU tokens rather than Smart Card tokens, these can be found under the “Tokens” tab, and “Search-ing” using the “Currently Used Tokens” tab.  DTU’s can be identified by the prefix “psuedo.”   For example: 4. Copy/paste this token into the VDI administrative interface, by selecting “Users”, “New”, and pasting in the token ID, and click “OK” - for example: 5. Assign the token (DTU) to a desktop, that is, in the VDI Admin Gui, select “Pool”, “Desktop”, select the VM, and click "Assign" and select the token you want, for example: In addition to assigning tokens to desktops, you'll need to bypass the login screen.  To do this, you need to do two things:  1.  Disable VDI client authentication with:  /opt/SUNWvda/sbin/vda settings-setprops -p clientauthentication=Disabled 2. Disable the VDI login screen – to do this,  add a kiosk argument of "-n" to the Sun Ray kiosk arguments screen.   You set this on the Sun Ray administration page - "Advanced", "Kiosk Mode", "Edit", and add the “-n” option to the arguments screen, for example: 3.  Restart both the Sun Ray and VDI services: # /opt/SUNWut/sbin/utstart –c # /opt/SUNWvda/sbin/vda-service restart Remember, if you have a question for us, please post on Twitter with our hashtag (again, it's #AskOracleVirtualization), and we'll try to answer it if we can. See you next time!

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• How to completely remove a package that didn't install properly?

  - by chtfn

  I recently installed a package from a ppa on Ubuntu 12.04 beta, but apparently it didn't work out, and now it is giving me errors at every update or install I make, even after deactivating the ppa from my sources. This is what I get when I try uninstalling from USC: installArchives() failed: (Reading database ... (Reading database ... 5% (Reading database ... 10% (Reading database ... 15% (Reading database ... 20% (Reading database ... 25% (Reading database ... 30% (Reading database ... 35% (Reading database ... 40% (Reading database ... 45% (Reading database ... 50% (Reading database ... 55% (Reading database ... 60% (Reading database ... 65% (Reading database ... 70% (Reading database ... 75% (Reading database ... 80% (Reading database ... 85% (Reading database ... 90% (Reading database ... 95% (Reading database ... 100% (Reading database ... 295120 files and directories currently installed.) Removing oracle-java7-installer ... update-alternatives: error: unknown argument `cdrom' dpkg: error processing oracle-java7-installer (--remove): subprocess installed pre-removal script returned error exit status 2 No apport report written because MaxReports is reached already Downloading... --2012-04-12 13:13:21-- http://download.oracle.com/otn-pub/java/jdk/7u3-b04/jdk-7u3-linux-i586.tar.gz Rsolution de download.oracle.com (download.oracle.com)... 203.13.161.233, 203.13.161.234 Connexion vers download.oracle.com (download.oracle.com)|203.13.161.233|:80... connect. requte HTTP transmise, en attente de la rponse... 302 Moved Temporarily Emplacement: https://edelivery.oracle.com/otn-pub/java/jdk/7u3-b04/jdk-7u3-linux-i586.tar.gz [suivant] --2012-04-12 13:13:21-- https://edelivery.oracle.com/otn-pub/java/jdk/7u3-b04/jdk-7u3-linux-i586.tar.gz Rsolution de edelivery.oracle.com (edelivery.oracle.com)... 173.223.150.174 Connexion vers edelivery.oracle.com (edelivery.oracle.com)|173.223.150.174|:443... connect. requte HTTP transmise, en attente de la rponse... 302 Moved Temporarily Emplacement: http://download.oracle.com/errors/download-fail-1505220.html [suivant] --2012-04-12 13:13:22-- http://download.oracle.com/errors/download-fail-1505220.html Connexion vers download.oracle.com (download.oracle.com)|203.13.161.233|:80... connect. requte HTTP transmise, en attente de la rponse... 200 OK Longueur: 5307 (5,2K) [text/html] Sauvegarde en : ./jdk-7u3-linux-i586.tar.gz 0K ..... 100% 4,94M=0,001s 2012-04-12 13:13:22 (4,94 MB/s) - ./jdk-7u3-linux-i586.tar.gz sauvegard [5307/5307] Download done. sha256sum mismatch jdk-7u3-linux-i586.tar.gz Oracle JDK 7 is NOT installed. dpkg: error while cleaning up: subprocess installed post-installation script returned error exit status 1 Errors were encountered while processing: oracle-java7-installer Error in function: I also tried "remove completely" from synaptic but it doesn't work either. Thank you for your help in advance!

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• SQL Server Optimizer Malfunction?

  - by Tony Davis

  There was a sharp intake of breath from the audience when Adam Machanic declared the SQL Server optimizer to be essentially "stuck in 1997". It was during his fascinating "Query Tuning Mastery: Manhandling Parallelism" session at the recent PASS SQL Summit. Paraphrasing somewhat, Adam (blog | @AdamMachanic) offered a convincing argument that the optimizer often delivers flawed plans based on assumptions that are no longer valid with today’s hardware. In 1997, when Microsoft engineers re-designed the database engine for SQL Server 7.0, SQL Server got its initial implementation of a cost-based optimizer. Up to SQL Server 2000, the developer often had to deploy a steady stream of hints in SQL statements to combat the occasionally wilful plan choices made by the optimizer. However, with each successive release, the optimizer has evolved and improved in its decision-making. It is still prone to the occasional stumble when we tackle difficult problems, join large numbers of tables, perform complex aggregations, and so on, but for most of us, most of the time, the optimizer purrs along efficiently in the background. Adam, however, challenged further any assumption that the current optimizer is competent at providing the most efficient plans for our more complex analytical queries, and in particular of offering up correctly parallelized plans. He painted a picture of a present where complex analytical queries have become ever more prevalent; where disk IO is ever faster so that reads from disk come into buffer cache faster than ever; where the improving RAM-to-data ratio means that we have a better chance of finding our data in cache. Most importantly, we have more CPUs at our disposal than ever before. To get these queries to perform, we not only need to have the right indexes, but also to be able to split the data up into subsets and spread its processing evenly across all these available CPUs. Improvements such as support for ColumnStore indexes are taking things in the right direction, but, unfortunately, deficiencies in the current Optimizer mean that SQL Server is yet to be able to exploit properly all those extra CPUs. Adam’s contention was that the current optimizer uses essentially the same costing model for many of its core operations as it did back in the days of SQL Server 7, based on assumptions that are no longer valid. One example he gave was a "slow disk" bias that may have been valid back in 1997 but certainly is not on modern disk systems. Essentially, the optimizer assesses the relative cost of serial versus parallel plans based on the assumption that there is no IO cost benefit from parallelization, only CPU. It assumes that a single request will saturate the IO channel, and so a query would not run any faster if we parallelized IO because the disk system simply wouldn’t be able to handle the extra pressure. As such, the optimizer often decides that a serial plan is lower cost, often in cases where a parallel plan would improve performance dramatically. It was challenging and thought provoking stuff, as were his techniques for driving parallelism through query logic based on subsets of rows that define the "grain" of the query. I highly recommend you catch the session if you missed it. I’m interested to hear though, when and how often people feel the force of the optimizer’s shortcomings. Barring mistakes, such as stale statistics, how often do you feel the Optimizer fails to find the plan you think it should, and what are the most common causes? Is it fighting to induce it toward parallelism? Combating unexpected plans, arising from table partitioning? Something altogether more prosaic? Cheers, Tony.

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• My 2D collision code does not work as expected. How do I fix it?

  - by farmdve

  I have a simple 2D game with a tile-based map. I am new to game development, I followed the LazyFoo tutorials on SDL. The tiles are in a bmp file, but each tile inside it corresponds to an internal number of the type of tile(color, or wall). The game is simple, but the code is a lot so I can only post snippets. // Player moved out of the map if((player.box.x < 0)) player.box.x += GetVelocity(player, 0); if((player.box.y < 0)) player.box.y += GetVelocity(player, 1); if((player.box.x > (LEVEL_WIDTH - DOT_WIDTH))) player.box.x -= GetVelocity(player, 0); if((player.box.y > (LEVEL_HEIGHT - DOT_HEIGHT))) player.box.y -= GetVelocity(player, 1); // Now that we are here, we check for collisions if(touches_wall(player.box)) { if(player.box.x < player.prev_x) { player.box.x += GetVelocity(player, 0); } if(player.box.x > player.prev_x) { player.box.x -= GetVelocity(player, 0); } if(player.box.y < player.prev_y) { player.box.y += GetVelocity(player, 1); } if(player.box.y > player.prev_y) { player.box.y -= GetVelocity(player, 1); } } player.prev_x = player.box.x; player.prev_y = player.box.y; Let me explain, player is a structure with the following contents typedef struct { Rectangle box; //Player position on a map(tile or whatever). int prev_x, prev_y; // Previous positions int key_press[3]; // Stores which key was pressed/released. Limited to three keys. E.g Left,right and perhaps jump if possible in 2D int velX, velY; // Velocity for X and Y coordinate. //Health int health; bool main_character; uint32_t jump_ticks; } Player; And Rectangle is just a typedef of SDL_Rect. GetVelocity is a function that according to the second argument, returns the velocity for the X or Y axis. This code I have basically works, however inside the if(touches_wall(player.box)) if statement, I have 4 more. These 4 if statements are responsible for detecting collision on all 4 sides(up,down,left,right). However, they also act as a block for any other movement. Example: I move down the object and collide with the wall, as I continue to move down and still collide with the wall, I wish to move left or right, which is indeed possible(not to mention in 3D games), but remember the 4 if statements? They are preventing me from moving anywhere. The original code on the LazyFoo Productions website has no problems, but it was written in C++, so I had to rewrite most of it to work, which is probably where the problem comes from. I also use a different method of moving, than the one in the examples. Of course, that was just an example. I wish to be able to move no matter at which wall I collide. Before this bit of code, I had another one that had more logic in there, but it was flawed.

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• RemoveHandler Issues with Custom Events

  - by Jeff Certain

  This is a case of things being more complicated that I thought they should be. Since it took a while to figure this one out, I thought it was worth explaining and putting all of the pieces to the answer in one spot. Let me set the stage. Architecturally, I have the notion of generic producers and consumers. These put items onto, and remove items from, a queue. This provides a generic, thread-safe mechanism to load balance the creation and processing of work items in our application. Part of the IProducer(Of T) interface is: 1: Public Interface IProducer(Of T) 2: Event ItemProduced(ByVal sender As IProducer(Of T), ByVal item As T) 3: Event ProductionComplete(ByVal sender As IProducer(Of T)) 4: End Interface Nothing sinister there, is there? In order to simplify our developers’ lives, I wrapped the queue with some functionality to manage the produces and consumers. Since the developer can specify the number of producers and consumers that are spun up, the queue code manages adding event handlers as the producers and consumers are instantiated. Now, we’ve been having some memory leaks and, in order to eliminate the possibility that this was caused by weak references to event handles, I wanted to remove them. This is where it got dicey. My first attempt looked like this: 1: For Each producer As P In Producers 2: RemoveHandler producer.ItemProduced, AddressOf ItemProducedHandler 3: RemoveHandler producer.ProductionComplete, AddressOf ProductionCompleteHandler 4: producer.Dispose() 5: Next What you can’t see in my posted code are the warnings this caused. The 'AddressOf' expression has no effect in this context because the method argument to 'AddressOf' requires a relaxed conversion to the delegate type of the event. Assign the 'AddressOf' expression to a variable, and use the variable to add or remove the method as the handler.  Now, what on earth does that mean? Well, a quick Bing search uncovered a whole bunch of talk about delegates. The first solution I found just changed all parameters in the event handler to Object. Sorry, but no. I used generics precisely because I wanted type safety, not because I wanted to use Object. More searching. Eventually, I found this forum post, where Jeff Shan revealed a missing piece of the puzzle. The other revelation came from Lian_ZA in this post. However, these two only hinted at the solution. Trying some of what they suggested led to finally getting an invalid cast exception that revealed the existence of ItemProducedEventHandler. Hold on a minute! I didn’t create that delegate. There’s nothing even close to that name in my code… except the ItemProduced event in the interface. Could it be? Naaaaah. Hmmm…. Well, as it turns out, there is a delegate created by the compiler for each event. By explicitly creating a delegate that refers to the method in question, implicitly cast to the generated delegate type, I was able to remove the handlers: 1: For Each producer As P In Producers 2: Dim _itemProducedHandler As IProducer(Of T).ItemProducedEventHandler = AddressOf ItemProducedHandler 3: RemoveHandler producer.ItemProduced, _itemProducedHandler 4:  5: Dim _productionCompleteHandler As IProducer(Of T).ProductionCompleteEventHandler = AddressOf ProductionCompleteHandler 6: RemoveHandler producer.ProductionComplete, _productionCompleteHandler 7: producer.Dispose() 8: Next That’s “all” it took to finally be able to remove the event handlers and maintain type-safe code. Hopefully, this will save you the same challenges I had in trying to figure out how to fix this issue!

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