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• Cloud Computing: Start with the problem

  - by BuckWoody

  At one point in my life I would build my own computing system for home use. I wanted a particular video card, a certain set of drives, and a lot of memory. Not only could I not find those things in a vendor’s pre-built computer, but those were more expensive – by a lot. As time moved on and the computing industry matured, I actually find that I can buy a vendor’s system as cheaply – and in some cases far more cheaply – than I can build it myself.   This paradigm holds true for almost any product, even clothing and furniture. And it’s also held true for software… Mostly. If you need an office productivity package, you simply buy one or use open-sourced software for that. There’s really no need to write your own Word Processor – it’s kind of been done a thousand times over. Even if you need a full system for customer relationship management or other needs, you simply buy one. But there is no “cloud solution in a box”.  Sure, if you’re after “Software as a Service” – type solutions, like being able to process video (Windows Azure Media Services) or running a Pig or Hive job in Hadoop (Hadoop on Windows Azure) you can simply use one of those, or if you just want to deploy a Virtual Machine (Windows Azure Virtual Machines) you can get that, but if you’re looking for a solution to a problem your organization has, you may need to mix Software, Infrastructure, and perhaps even Platforms (such as Windows Azure Computing) to solve the issue. It’s all about starting from the problem-end first. We’ve become so accustomed to looking for a box of software that will solve the problem, that we often start with the solution and try to fit it to the problem, rather than the other way around.  When I talk with my fellow architects at other companies, one of the hardest things to get them to do is to ignore the technology for a moment and describe what the issues are. It’s interesting to monitor the conversation and watch how many times we deviate from the problem into the solution. So, in your work today, try a little experiment: watch how many times you go after a problem by starting with the solution. Tomorrow, make a conscious effort to reverse that. You might be surprised at the results.

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• What if I can't make my unit test fail in "Red, Green, Refactor" of TDD?

  - by Joshua Harris

  So let's say that I have a test: @Test public void MoveY_MoveZero_DoesNotMove() { Point p = new Point(50.0, 50.0); p.MoveY(0.0); Assert.assertAreEqual(50.0, p.Y); } This test then causes me to create the class Point: public class Point { double X; double Y; public void MoveY(double yDisplace) { throw new NotYetImplementedException(); } } Ok. It fails. Good. Then I remove the exception and I get green. Great, but of course I need to test if it changes value. So I write a test that calls p.MoveY(10.0) and checks if p.Y is equal to 60.0. It fails, so then I change the function to look like so: public void MoveY(double yDisplace) { Y += yDisplace; } Great, now I have green again and I can move on. I've tested not moving and moving in the positive direction, so naturally I should test a negative value. The only problem with this test is that if I wrote the test correctly, then it doesn't fail at first. That means that I didn't fit the principle of "Red, Green, Refactor." Of course, This is a first-world problem of TDD, but getting a fail at first is helpful in that it shows that your test can fail. Otherwise this seemingly innocent test that is just passing for incorrect reasons could fail later because it was written wrong. That might not be a problem if it happened 5 minutes later, but what if it happens to the poor-sap that inheirited your code two years later. What he knows is that MoveY does not work with negative values because that is what the test is telling him. But, it really could work and just be a bug in the test. I don't think that would happen in this particular case because the code sample is so simple, but if it were a large complicated system that might not be the case. It seems crazy to say that I want to fail my tests, but that is an important step in TDD, for good reasons.

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• Indefinite loops where the first time is different

  - by George T

  This isn't a serious problem or anything someone has asked me to do, just a seemingly simple thing that I came up with as a mental exercise but has stumped me and which I feel that I should know the answer to already. There may be a duplicate but I didn't manage to find one. Suppose that someone asked you to write a piece of code that asks the user to enter a number and, every time the number they entered is not zero, says "Error" and asks again. When they enter zero it stops. In other words, the code keeps asking for a number and repeats until zero is entered. In each iteration except the first one it also prints "Error". The simplest way I can think of to do that would be something like the folloing pseudocode: int number = 0; do { if(number != 0) { print("Error"); } print("Enter number"); number = getInput(); }while(number != 0); While that does what it's supposed to, I personally don't like that there's repeating code (you test number != 0 twice) -something that should generally be avoided. One way to avoid this would be something like this: int number = 0; while(true) { print("Enter number"); number = getInput(); if(number == 0) { break; } else { print("Error"); } } But what I don't like in this one is "while(true)", another thing to avoid. The only other way I can think of includes one more thing to avoid: labels and gotos: int number = 0; goto question; error: print("Error"); question: print("Enter number"); number = getInput(); if(number != 0) { goto error; } Another solution would be to have an extra variable to test whether you should say "Error" or not but this is wasted memory. Is there a way to do this without doing something that's generally thought of as a bad practice (repeating code, a theoretically endless loop or the use of goto)? I understand that something like this would never be complex enough that the first way would be a problem (you'd generally call a function to validate input) but I'm curious to know if there's a way I haven't thought of.

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• Mobile Apps: An Ongoing Revolution

  - by Steve Walker

  a guest post from Suhas Uliyar, VP Mobile Strategy, Product Management, Oracle The rise of smartphone apps have proved transformational for businesses, increasing the productivity of employees while simultaneously creating some seriously cool end user experiences. But this is a revolution that is only just beginning. Over the next few years, apps will change everything about the way enterprises work as well as overhauling the experiences of customers. The spark for this revolution is simplicity. Simplicity has already proved important for the front-end of apps, which are now often as compelling and intuitive as consumer apps. Businesses will encourage this trend, both to further increase employee productivity and to attract ‘digital natives’ (as employees and customers). With the variety of front-end development tools available already, this should be a simple mission for developers to accomplish – but front-end simplicity alone is not enough for the enterprise mobile revolution. Without the right content even the most user-friendly app is useless. Yet when it comes to integrating apps with ‘back-end’ systems to enable this content, developers often face a complex, costly and time-consuming task. Then there is security: how can developers strike a balance between complying with enterprise security policies and keeping the user experience simple? Complexity has acted as a brake on innovation, with integration and security compliance swallowing enterprise resources. This is why the simplification of integration, security and scalability is so important: it frees time and money for revolutionary innovation. The key is to put in place a complete and unified SOA integration platform that runs across the entire enterprise and enables organizations to easily integrate and connect applications across IT environments. The platform must also be capable of abstracting apps from the underlying OS and enabling a ‘write-once, run- anywhere’ capability for mobile devices - essential for BYOD environments and integrating third-party apps. Mobile Back-end-as-a-Service can also be very important in streamlining back-end integration. Mobile services offered through the cloud can simplify mobile application development with a standard approach to dealing with complex server-side programming and integration issues. This allows the business to innovate at its own pace while providing developers with a choice of tools to speed development and integration. Finally, there is security, which must be done in a way that encourages users to make the most of their mobile devices and applications. As mobile users, we want convenience and that is why we generally approve of businesses that adopt BYOD policies. Enterprises can safely encourage BYOD as they can separate, protect, and wipe corporate applications by installing a secure ‘container’ around corporate applications on any mobile device. BYOD management also means users’ personal applications and data can be kept separate from the enterprise information – giving them the confidence they need to embrace the use of their devices for corporate apps. Enterprises that place mobility at the heart of what they do will fundamentally transform their businesses and leap ahead of the competition. As businesses take to mobile platforms that simplify integration, security and scalability we will see a blossoming of innovation that will drive new levels of user convenience and create new ways of working that we are only beginning to imagine.

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• NDepend 4.0 Released

  - by Anthony Trudeau

  Last week version 4.0 of NDepend was released.  NDepend is a Visual Studio add-in designed for intense code analysis with the goal of high quality code.  A month ago I wrapped up my evaluation of the previous version of NDepend. The new version contains many minor changes, several bug fixes, and adds about 50 new code rules.  The version also adds support for Visual Studio 11, .NET Framework 4.5, and SilverLight 5.0.  But, the biggest change was the shift from CQL to CQLinq. Introducing CQLinq The latest version replaces the CQL rules language with CQLinq (CQL is still an option although the editor is buried).  As you might guess CQLinq is a flavor of Linq designed specifically for the code rules. The best way to illustrate the differences is with an example.  I used the following CQL example in Part 3 of my review: WARN IF Count > 0 IN SELECT TYPES WHERE IsInterface AND !NameLike “I” This same query looks like this when implemented in CQLinq: warnif count > 0 from t in Types where t.IsInterface == true && !t.NameLike(“I”) select t I like the syntax and it is a natural fit, but I found writing the queries frustrating in the Queries and Rules Edit window.  The Queries and Rules Edit window replaces the CQL Query Edit window.  The new editor has the same style of Intellisense as the previous editor.  However, it has a few annoyances.  The error indicator is a red block.  It has the tendency of obscuring your cursor.  Additionally, writing CQLing queries is like writing plain old Linq queries, so the fact that the editor uses Enter to select from Intellisense instead of Tab is jarring.  These issues can be an obstacle to writing queries quickly.CQLinq makes it possible to write rules that weren't possible before.  Additionally, a JustMyCode domain is now possible making it easy to eliminate generated code from the analysis.Should you Buy? I recommend NDepend overall.  It has some rough points for me that I have detailed in my earlier evaluation (starting here).  But, it’s definitely worth the money.  The bigger question is: should I pay for the upgrade to 4.0?  At this point I’m on the fence, but I would go for it if you need support for Visual Studio 2011, .NET Framework 4.5, or Silverlight 5.0; or if you need one of the many rules that weren't possible before CQLinq. Disclaimer: Patrick Smacchia contacted me about reviewing NDepend. I received a free license in return for sharing my experiences and talking about the capabilities of the add-in on this site. There is no expectation of a positive review elicited from the author of NDepend. Resources: NDepend Release Notes

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• Software Tuned to Humanity

  - by Phil Factor

  I learned a great deal from a cynical old programmer who once told me that the ideal length of time for a compiler to do its work was the same time it took to roll a cigarette. For development work, this is oh so true. After intently looking at the editing window for an hour or so, it was a relief to look up, stretch, focus the eyes on something else, and roll the possibly-metaphorical cigarette. This was software tuned to humanity. Likewise, a user’s perception of the “ideal” time that an application will take to move from frame to frame, to retrieve information, or to process their input has remained remarkably static for about thirty years, at around 200 ms. Anything else appears, and always has, to be either fast or slow. This could explain why commercial applications, unlike games, simulations and communications, aren’t noticeably faster now than they were when I started programming in the Seventies. Sure, they do a great deal more, but the SLAs that I negotiated in the 1980s for application performance are very similar to what they are nowadays. To prove to myself that this wasn’t just some rose-tinted misperception on my part, I cranked up a Z80-based Jonos CP/M machine (1985) in the roof-space. Within 20 seconds from cold, it had loaded Wordstar and I was ready to write. OK, I got it wrong: some things were faster 30 years ago. Sure, I’d now have had all sorts of animations, wizzy graphics, and other comforting features, but it seems a pity that we have used all that extra CPU and memory to increase the scope of what we develop, and the graphical prettiness, but not to speed the processes needed to complete a business procedure. Never mind the weight, the response time’s great! To achieve 200 ms response times on a Z80, or similar, performance considerations influenced everything one did as a developer. If it meant writing an entire application in assembly code, applying every smart algorithm, and shortcut imaginable to get the application to perform to spec, then so be it. As a result, I’m a dyed-in-the-wool performance freak and find it difficult to change my habits. Conversely, many developers now seem to feel quite differently. While all will acknowledge that performance is important, it’s no longer the virtue is once was, and other factors such as user-experience now take precedence. Am I wrong? If not, then perhaps we need a new school of development technique to rival Agile, dedicated once again to producing applications that smoke the rear wheels rather than pootle elegantly to the shops; that forgo skeuomorphism, cute animation, or architectural elegance in favor of the smell of hot rubber. I struggle to name an application I use that is truly notable for its blistering performance, and would dearly love one to do my everyday work – just as long as it doesn’t go faster than my brain.

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• Loading levels from .txt or .XML for XNA

  - by Dave Voyles

  I'm attemptin to add multiple levels to my pong game. I'd like to simply exchange a few elements with each level, nothing crazy. Just the background texture, the color of the AI paddle (the one on the right side), and the music. It seems that the best way to go about this is by utilizing the StreamReader to read and write the files from XML. If there is a better, or more efficient alternative way then I'm all for it. In looking over the XNA Starter Platformer Kit provided by MS it seems that they've done it in this manner as well. I'm perplexed by a few things, however, namely parts within the Level class which aren't commented. /// <summary> /// Iterates over every tile in the structure file and loads its /// appearance and behavior. This method also validates that the /// file is well-formed with a player start point, exit, etc. /// </summary> /// <param name="fileStream"> /// A stream containing the tile data. /// </param> private void LoadTiles(Stream fileStream) { // Load the level and ensure all of the lines are the same length. int width; List<string> lines = new List<string>(); using (StreamReader reader = new StreamReader(fileStream)) { string line = reader.ReadLine(); width = line.Length; while (line != null) { lines.Add(line); if (line.Length != width) throw new Exception(String.Format("The length of line {0} is different from all preceeding lines.", lines.Count)); line = reader.ReadLine(); } } What does width = line.Length mean exactly? I mean I know how it reads the line, but what difference does it make if one line is longer than any of the others? Finally, their levels are simply text files that look like this: .................... .................... .................... .................... .................... .................... .................... .........GGG........ .........###........ .................... ....GGG.......GGG... ....###.......###... .................... .1................X. #################### It can't be that easy..... Can it?

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• ConsumeStructuredBuffer, what am I doing wrong?

  - by John

  I'm trying to implement the 3rd exercise in chapter 12 of Introduction to 3D Game Programming with DirectX 11, that is: Implement a Compute Shader to calculate the length of 64 vectors. Previous exercises ask you to do the same with typed buffers and regular structured buffers and I had no problems with them. For what I've read, [Consume|Append]StructuredBuffers are bound to the pipeline using UnorderedAccessViews (as long as they use the D3D11_BUFFER_UAV_FLAG_APPEND, and the buffers have both D3D11_BIND_SHADER_RESOURCE and D3D11_BIND_UNORDERED_ACCESS bind flags). Problem is: my AppendStructuredBuffer works, since I can append data to it and retrieve it from the application to write to a results file, but the ConsumeStructuredBuffer always returns zeroed data. Data is in the buffer, since if I change the UAV to a ShaderResourceView and to a StructuredBuffer in the HLSL side it works. I don't know what I am missing: Should I initialize the ConsumeStructuredBuffer on the GPU, or can I do it when I create the buffer (as I amb currently doing). Is it OK to bind the buffer with a UAV as described above? Do I need to bind it as a ShaderResourceView somehow? Maybe I am missing some step? This is the declaration of buffers in the Compute Shader: struct Data { float3 v; }; struct Result { float l; }; ConsumeStructuredBuffer<Data> gInput; AppendStructuredBuffer<Result> gOutput; And here the creation of the buffer and UAV for input data: D3D11_BUFFER_DESC inputDesc; inputDesc.Usage = D3D11_USAGE_DEFAULT; inputDesc.ByteWidth = sizeof(Data) * mNumElements; inputDesc.BindFlags = D3D11_BIND_SHADER_RESOURCE | D3D11_BIND_UNORDERED_ACCESS; inputDesc.CPUAccessFlags = 0; inputDesc.StructureByteStride = sizeof(Data); inputDesc.MiscFlags = D3D11_RESOURCE_MISC_BUFFER_STRUCTURED; D3D11_SUBRESOURCE_DATA vinitData; vinitData.pSysMem = &data[0]; HR(md3dDevice->CreateBuffer(&inputDesc, &vinitData, &mInputBuffer)); D3D11_UNORDERED_ACCESS_VIEW_DESC uavDesc; uavDesc.Format = DXGI_FORMAT_UNKNOWN; uavDesc.ViewDimension = D3D11_UAV_DIMENSION_BUFFER; uavDesc.Buffer.FirstElement = 0; uavDesc.Buffer.Flags = D3D11_BUFFER_UAV_FLAG_APPEND; uavDesc.Buffer.NumElements = mNumElements; md3dDevice->CreateUnorderedAccessView(mInputBuffer, &uavDesc, &mInputUAV); Initial data is an array of Data structs, which contain a XMFLOAT3 with random data. I bind the UAV to the shader using the Effects framework: ID3DX11EffectUnorderedAccessViewVariable* Input = mFX->GetVariableByName("gInput")->AsUnorderedAccessView(); Input->SetUnorderedAccessView(uav); // uav is mInputUAV Any ideas? Thank you.

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• HDMI sound gone, can't figure out how to turn it back on

  - by Oli

  I have had an Acer Revo box as a media centre for a while. I recently installed Ubuntu Server (10.10) on it and polished it up with nodm (one of the most simple ways to launch an X session) and installed boxee. It's been working fine for over a month. It's just running ALSA. I've had problems with PulseAudio/Boxee/HDMI before so I wanted to keep it simple. And that worked. It pushed both PCM and digital (AAC and various Dolby codecs) over HDMI perfectly. But I restarted it the other day after mucking around with some nfs configuration and now there isn't any sound. The hardware is an ION chipset. Nvidia 9400M graphics with Nvidia MCP79/7A audio. One thing I have noticed is there doesn't appear to be any sign of a IEC958 device. A traditional fix in the past for fresh installs has been to load alsamixer, find the IEC device and toggle its mute but I can't. I'm certain this used to represent the HDMI output. It just doesn't seem to exist any more unless I run sudo alsa-utils restart while boxee is running, when I see it in an error message: * Shutting down ALSA... [ OK ] * Setting up ALSA... * warning: 'alsactl restore' failed with error message 'alsactl: set_control:1388: Cannot write control '2:0:0:IEC958 Playback Default:0' : Operation not permitted'... ...done. When nodm (and thus boxee) aren't running, I don't see this error but alsamixer still doesn't show the IEC channel. aplay -l gives: card 0: NVidia [HDA NVidia], device 0: ALC662 rev1 Analog [ALC662 rev1 Analog] Subdevices: 1/1 Subdevice #0: subdevice #0 card 0: NVidia [HDA NVidia], device 3: HDMI 0 [HDMI 0] Subdevices: 0/1 Subdevice #0: subdevice #0 Its section in lshw reads: *-multimedia description: Audio device product: MCP79 High Definition Audio vendor: nVidia Corporation physical id: 8 bus info: pci@0000:00:08.0 version: b1 width: 32 bits clock: 66MHz capabilities: pm bus_master cap_list configuration: driver=HDA Intel latency=0 maxlatency=5 mingnt=2 resources: irq:22 memory:fae78000-fae7bfff I was running on the stock PAE kernel but now it's running on 2.6.37.1. I upgraded to see if that fixed things; it didn't. I'm considering a reinstall but I hate doing that because a) there's a bit of custom configuration in getting X and Boxee to start on boot and b) I don't know what the problem is. If I reinstall this time, I'll end up doing that every time the sound breaks. I love Ubuntu but I don't want to install it once a month. Is there any way to forcibly reset all alsa settings and restart from scratch (without doing a reinstall)? Any other tips? If you need more information, just ask.

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• Best way to remote restart Ubuntu from Windows machine

  - by robsoft

  Background: I'm looking to put a series of Ubuntu machines into retail locations, they're being used as dumb kiosks to show a series of slides onto large LCD panel TV screens. Once installed, they won't have a keyboard or mouse connected but will have a fixed IP on the local network. Everything is configured to auto-start, no automatic updates, no power saving etc - I think we're pretty-much good to go apart from one thing. I need the retail staff to be able to restart the boxes if a problem arises. We have VNC running (now that we've turned off desktop enhancements!) so that we can remotely get into the machines if we need to, but that's not something we would allow the retail staff to do. The machines are going to be physically 'out of the way' (probably in the ceiling space) so the power button is not easily accessible!. I'd like to have some means of allowing the retail staff to restart the Ubuntu machine, from the desktop of one of their Windows terminals. I don't really want to give them some kind of raw terminal access (the command line will frighten them!) and I don't want them to use VNC (as stated above). Ideally there would be an icon on the Windows desktop, they double-click it, reply to a simple 'are you sure?' prompt, and then the Ubuntu box is told to restart. The Windows side of that won't be a problem, we can write something using Delphi, Python & Qt4, whatever - it's the Ubuntu side of it I'm stuck with. Out of sight/view, could I have a Windows program open a terminal across the network and tell Ubuntu to restart? Is this what SSH could be used for (I have never set that kind of thing up). The Windows programming side isn't really an issue, it's just that I'm a total Ubuntu noob and don't know where to start from the platform point of view. The other thing we considered is also having the machine automatically restart itself at a set time each day (obviously out of store hours!). To me, that seems a bit unnecessary (though forcing a restart once a week/month might be worthwhile). Any thoughts or suggestions? Being able to restart the box on demand across the network is my prime requirement.

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• Enabling EUS support in OUD 11gR2 using command line interface

  - by Sylvain Duloutre

  Enterprise User Security (EUS) allows Oracle Database to use users & roles stored in LDAP for authentication and authorization.Since the 11gR2 release, OUD natively supports EUS. EUS can be easily configured during OUD setup. ODSM (the graphical admin console) can also be used to enable EUS for a new suffix. However, enabling EUS for a new suffix using command line interface is currently not documented, so here is the procedure: Let's assume that EUS support was enabled during initial setup.Let's o=example be the new suffix I want to use to store Enterprise users. The following sequence of command must be applied for each new suffix: // Create a local database holding EUS context infodsconfig create-workflow-element --set base-dn:cn=OracleContext,o=example --set enabled:true --type db-local-backend --element-name exampleContext -n // Add a workflow element in the call path to generate on the fly attributes required by EUSdsconfig create-workflow-element --set enabled:true --type eus-context --element-name eusContext --set next-workflow-element:exampleContext -n // Add the context to a workflow for routingdsconfig create-workflow --set base-dn:cn=OracleContext,o=example --set enabled:true --set workflow-element:eusContext --workflow-name exampleContext_workflow -n //Add the new workflow to the appropriate network groupdsconfig set-network-group-prop --group-name network-group --add workflow:exampleContext_workflow -n // Create the local database for o=exampledsconfig create-workflow-element --set base-dn:o=example --set enabled:true --type db-local-backend --element-name example -n // Create a workflow element in the call path to the user data to generate on the fly attributes expected by EUS dsconfig create-workflow-element --set enabled:true --set eus-realm:o=example --set next-workflow-element:example --type eus --element-name eusWfe// Add the db to a workflow for routingdsconfig create-workflow --set base-dn:o=example --set enabled:true --set workflow-element:eusWfe --workflow-name example_workflow -n //Add the new workflow to the appropriate network groupdsconfig set-network-group-prop --group-name network-group --add workflow:example_workflow -n  // Add the appropriate acis for EUSdsconfig set-access-control-handler-prop \           --add global-aci:'(target="ldap:///o=example")(targetattr="authpassword")(version 3.0; acl "EUS reads authpassword"; allow (read,search,compare) userdn="ldap:///??sub?(&(objectclass=orclservice)(objectclass=orcldbserver))";)' dsconfig set-access-control-handler-prop \       --add global-aci:'(target="ldap:///o=example")(targetattr="orclaccountstatusevent")(version 3.0; acl "EUS writes orclaccountstatusenabled"; allow (write) userdn="ldap:///??sub?(&(objectclass=orclservice)(objectclass=orcldbserver))";)' Last but not least you must adapt the content of the ${OUD}/config/EUS/eusData.ldif  file with your suffix value then inport it into OUD.

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• ANTS Memory Profiler 7.0

  - by Sam Abraham

  In the next few lines, I would like to briefly review ANTS Memory Profiler 7.0.  I was honored to be extended the opportunity to review this valuable tool as part of the GeeksWithBlogs influencers Program, a quarterly award providing its recipients access to valuable tools and enabling them with an opportunity to provide a brief write-up reviewing the complimentary tools they receive.   Typical Usage   ANTS Memory Profiler 7.0 is very intuitive and easy to use for any user be it novice or expert. A simple yet comprehensive menu screen enables the selection of the appropriate program type to profile as well as the executable or site for this program.   A typical use case starts with establishing a baseline memory snapshot, which tells us the initial memory cost used by the program under normal or low activity conditions. We would then take a second snapshot after the program has performed an activity which we want to investigate for memory leaks. We can then compare the initial baseline snapshot against the snapshot when the program has completed processing the activity in question to study anomalies in memory that did not get freed-up after the program has completed its performed function. The following are some screenshots outlining the selection of the program to profile (an executable for this demonstration’s purposes).   Figure 1 - Getting Started   Figure 2 - Selecting an Application to Profile     Features and Options   Right after the second snapshot is generated, Memory Profiler gives us immediate access to information on memory fragmentation, size differences between snapshots, unmanaged memory allocation and statistics on the largest classes taking up un-freed memory space.   We would also have the option to itemize objects held in memory grouped by object types within which we can study the instances allocated of each type. Filtering options enable us to quickly narrow object instances we are interested in.   Figure 3 - Easily accessible Execution Memory Information   Figure 4 - Class List   Figure 5 - Instance List   Figure 6-  Retention Graph for a Particular Instance   Conclusion I greatly enjoyed the opportunity to evaluate ANTS Memory Profiler 7.0. The tool's intuitive User Interface design and easily accessible menu options enabled me to quickly identify problem areas where memory was left unfreed in my code.     Tutorials and References  FInd out more About ANTS Memory Profiler 7.0 http://www.red-gate.com/supportcenter/Product?p=ANTS Memory Profiler   Checkout what other reviewers of this valuable tool have already shared: http://geekswithblogs.net/BlackRabbitCoder/archive/2011/03/10/ants-memory-profiler-7.0.aspx http://geekswithblogs.net/mikebmcl/archive/2011/02/28/ants-memory-profiler-7.0-review.aspx

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• determine if udp socket can be accessed via external client

  - by JohnMerlino

  I don't have access to company firewall server. but supposedly the port 1720 is open on my one ubuntu server. So I want to test it with netcat: sudo nc -ul 1720 The port is listening on the machine ITSELF: sudo netstat -tulpn | grep nc udp 0 0 0.0.0.0:1720 0.0.0.0:* 29477/nc The port is open and in use on the machine ITSELF: lsof -i -n -P | grep 1720 gateway 980 myuser 8u IPv4 187284576 0t0 UDP *:1720 Checked the firewall on current server: sudo ufw allow 1720/udp Skipping adding existing rule Skipping adding existing rule (v6) sudo ufw status verbose | grep 1720 1720/udp ALLOW IN Anywhere 1720/udp ALLOW IN Anywhere (v6) But I try echoing data to it from another computer (I replaced the x's with the real integers): echo "Some data to send" | nc xx.xxx.xx.xxx 1720 But it didn't write anything. So then I try with telnet from the other computer as well: telnet xx.xxx.xx.xxx 1720 Trying xx.xxx.xx.xxx... telnet: connect to address xx.xxx.xx.xxx: Operation timed out telnet: Unable to connect to remote host Although I don't think telnet works with udp sockets. I ran nmap from another computer within the same local network and this is what I got: sudo nmap -v -A -sU -p 1720 xx.xxx.xx.xx Starting Nmap 5.21 ( http://nmap.org ) at 2013-10-31 15:41 EDT NSE: Loaded 36 scripts for scanning. Initiating Ping Scan at 15:41 Scanning xx.xxx.xx.xx [4 ports] Completed Ping Scan at 15:41, 0.10s elapsed (1 total hosts) Initiating Parallel DNS resolution of 1 host. at 15:41 Completed Parallel DNS resolution of 1 host. at 15:41, 0.00s elapsed Initiating UDP Scan at 15:41 Scanning xtremek.com (xx.xxx.xx.xx) [1 port] Completed UDP Scan at 15:41, 0.07s elapsed (1 total ports) Initiating Service scan at 15:41 Initiating OS detection (try #1) against xtremek.com (xx.xxx.xx.xx) Retrying OS detection (try #2) against xtremek.com (xx.xxx.xx.xx) Initiating Traceroute at 15:41 Completed Traceroute at 15:41, 0.01s elapsed NSE: Script scanning xx.xxx.xx.xx. NSE: Script Scanning completed. Nmap scan report for xtremek.com (xx.xxx.xx.xx) Host is up (0.00013s latency). PORT STATE SERVICE VERSION 1720/udp closed unknown Too many fingerprints match this host to give specific OS details Network Distance: 1 hop TRACEROUTE (using port 1720/udp) HOP RTT ADDRESS 1 0.13 ms xtremek.com (xx.xxx.xx.xx) Read data files from: /usr/share/nmap OS and Service detection performed. Please report any incorrect results at http://nmap.org/submit/ . Nmap done: 1 IP address (1 host up) scanned in 2.04 seconds Raw packets sent: 27 (2128B) | Rcvd: 24 (2248B). The only thing I can think of is a firewall or vpn issue. Is there anything else I can check for before requesting that they look at the firewall server again?

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• Java: How to manage UDP client-server state

  - by user92947

  I am trying to write a Java application that works similar to MapReduce. There is a server and several workers. Workers may come and go as they please and the membership to the group has a soft-state. To become a part of the group, the worker must send a UDP datagram to the server, but to continue to be part of the group, the worker must send the UDP datagram to the server every 5 minutes. In order to accommodate temporary errors, a worker is allowed to miss as many as two consecutive periodic UDP datagrams. So, the server must keep track of the current set of workers as well as the last time each worker had sent a UDP datagram. I've implemented a class called WorkerListener that implements Runnable and listens to UDP datagrams on a particular UDP port. Now, to keep track of active workers, this class may maintain a HashSet (or HashMap). When a datagram is received, the server may query the HashSet to check if it is a new member. If so, it can add the new worker to the group by adding an entry into the HashSet. If not, it must reset a "timer" for the worker, noting that it has just heard from the corresponding worker. I'm using the word timer in a generic sense. It doesn't have to be a clock of sorts. Perhaps this could also be implemented using int or long variables. Also, the server must run a thread that continuously monitors the timers for the workers to see that a client that times out on two consecutive datagram intervals, it is removed from the HashSet. I don't want to do this in the WorkerListener thread because it would be blocking on the UDP datagram receive() function. If I create a separate thread to monitor the worker HashSet, it would need to be a different class, perhaps WorkerRegistrar. I must share the HashSet with that thread. Mutual exclusion must also be implemented, then. My question is, what is the best way to do this? Pointers to some sample implementation would be great. I want to use the barebones JDK implementation, and not some fancy state maintenance API that takes care of everything, because I want this to be a useful demonstration for a class that I am teaching. Thanks

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• Turnkey with LightSwitch

  - by Laila

  Microsoft has long wanted to find a replacement for Microsoft Access. The best attempt yet, which is due out in, or before, September is Visual Studio LightSwitch, with which it is said to be as 'easy as flipping a switch' to use Silverlight to create simple form-driven business applications. It is easy to get confused by the various initiatives from Microsoft. No, this isn't WebMatrix. There is no 'Razor', for this isn't meant for cute little ecommerce sites, but is designed to build simple database-applications of the card-box type. It is more clearly a .NET-based solution to the problem that every business seems to suffer from; the plethora of Access-based, and Excel-based 'private' and departmental database-applications. These are a nightmare for any IT department since they are often 'stealth' applications built by the business in the teeth of opposition from the IT Department zealots. As they are undocumented, it is scarily easy to bring a whole department into disarray by decommissioning a PC tucked under a desk somewhere. With LightSwitch, it is easy to re-write such applications in a standard, maintainable, way, using a SQL Server database, deployed somewhere reasonably safe such as Azure. Even Sharepoint or Windows Communication Foundation can be used as data sources. Oracle's ApEx has taken off remarkably well, and has shaken the perception that, for the business user, Oracle must remain a mystic force accessible only to the priests and acolytes. Microsoft, by comparison had only Access, which was first released in 1992, the year of the Madonna conical bustier. It looks just as dated. Microsoft badly needed an entirely new solution to the same business requirement that led to Access's and Foxpro's long-time popularity, but which had the same allure as ApEx. LightSwitch is sound in its ideas, and comfortingly conventional in its architecture. By giving an easy access to SQL Server databases, and providing a 'thumb and blanket' migration path to Access-heads, LightSwitch seems likely to offer a simple way of pulling more Microsoft users into the .NET community. If Microsoft puts its weight behind it, then it will give some glimmer of hope to the many Silverlight developers that Microsoft is capable of seeing through its .NET revolution.

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• Several New Hints

  - by Ondrej Brejla

  Hi all! Today we would like to introduce you some of our new experimental hints for NetBeans 7.2. They are called: Unused Use Statement and Immutable Variables. Unused Use Statement This hint is quite simple. It highlights (underlines) your use statements, which are not used. Typical use case is after some refactoring, when you forgot to remove some obsolete use statements. This hint warns you on them and allows you to remove them easily. Just click on the hint bulb in the gutter and select Remove Unused Use Statement. And of course, it works in multiple use statements combined too. Immutable Variables The next one is the hint which checks too many assignments into a variable. And why? That's simple. Mostly you should use just one assignment into one variable. But sometimes you are lazy and you do something like: But it's quite wrong, because what you really do is: And that's exactly the case, when our new hint warns you, that Too many assignments (2) into variable $foo occured. Nothing more. Yes, we know that there are some cases, where could be more assignments and no warning should occur, e.g.: Because maybe one likes longer increment syntax more than the short one. So we tried to handle these cases to don't bother you if it's not a need. Note: We are almost sure that this hint doesn't cover all your use cases, because there are a lot of them. So if you find something strange, write it into our bugzilla so we can handle it better for you. Thanks for your patience! And the last thing is, that you can set the number of allowed assignments in Tools -> Options -> Editor -> Hints -> PHP: Immutable Variables. Note: This hint works just for a common variables, not for fields. We have an enhancement request for that and it should be implemented in next version of NetBeans (probably 7.3). And that's all for today and as usual, please test it and if you find something strange, don't hesitate to file a new issue (product php, component Editor). Thanks.

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• I owe you an explanation

  - by Blueberry Coder

  Welcome to my blog! I am Frédéric Desbiens, a new member of the ADF Product Management team.  I joined Oracle only a few weeks ago. My boss is Grant Ronald, and I have the privilege to work in the same team as Susan Duncan, Frank Nimphius, Lynn Munsinger and Chris Muir. I share with them a passion for all things Java and ADF. With this blog, I hope to help you be more successful with our products – whether you are a customer or a partner. You may have heard of me before. Maybe you have my book in your bookshelf; or maybe we met at a conference. I went to JavaOne, ODTUG Kaleidoscope and Oracle OpenWorld in the past, when I worked for a major consulting firm. I will spare you all the details of my career; you can have a look at my LinkedIn profile if you are curious about my past.  Usually, my posts will be of a technical nature, and will focus on Oracle ADF and Oracle JDeveloper. SOA and portals have always been two topics of interest for me, however, and I will write about them. Over time, you will probably get acquainted with my « strategic » side as well. I devour history books, and always had a tendency to look at the big picture. I will probably not resist to the temptation of mixing IT and history, but this will be occasional, I promise!  At this point, I owe you an explanation about the title of the blog. I am French-Canadian, and wanted to evoke my roots in an obvious yet unobtrusive way. I was born in Chicoutimi, which is one of the main cities found in the Saguenay-Lac-Saint-Jean region. Traditionally, a large part of the wild blueberry production of the province of Québec come from there. A common nickname for the inhabitants is thus Les Bleuets, « The Blueberries » in English. I hope to see you around. You can also follow me on Twitter under  @BlueberryCoder.

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• Reading a ZFS USB drive with Mac OS X Mountain Lion

  - by Karim Berrah

  The problem: I'm using a MacBook, mainly with Solaris 11, but something with Mac OS X (ML). The only missing thing is that Mac OS X can't read my external ZFS based USB drive, where I store all my data. So, I decided to look for a solution. Possible solution: I decided to use VirtualBox with a Solaris 11 VM as a passthrough to my data. Here are the required steps: Installing a Solaris 11 VM Install VirtualBox on your Mac OS X, add the extension pack (needed for USB) Plug your ZFS based USB drive on your Mac, ignore it when asked to initialize it. Create a VM for Solaris (bridged network), and before installing it, create a USB filter (in the settings of your Vbox VM, go to Ports, then USB, then add a new USB filter from the attached device "grey usb-connector logo with green plus sign")  Install a Solaris 11 VM, boot it, and install the Guest addition check with "ifconfg -a" the IP address of your Solaris VM Creating a path to your ZFS USB drive In MacOS X, use the "Disk Utility" to unmount the USB attached drive, and unplug the USB device. Switch back to VirtualBox, select the top of the window where your Solaris 11 is running plug your ZFS USB drive, select "ignore" if Mac OS invite you to initialize the disk In the VirtualBox VM menu, go to "Devices" then "USB Devices" and select from the dropping menu your "USB device" Connection your Solaris VM to the USB drive Inside Solaris, you might now check that your device is accessible by using the "format" cli command If not, repeat previous steps Now, with root privilege, force a zpool import -f myusbdevicepoolname because this pool was created on another system check that you see your new pool with "zpool status" share your pool with NFS: share -F NFS /myusbdevicepoolname Accessing the USB ZFS drive from Mac OS X This is the easiest step: access an NFS share from mac OS Create a "ZFSdrive" folder on your MacOS desktop from a terminal under mac OS: mount -t nfs IPadressofMySoalrisVM:/myusbdevicepoolname  /Users/yourusername/Desktop/ZFSdrive et voila ! you might access your data, on a ZFS USB drive, directly from your Mountain Lion Desktop. You might play with the share rights in order to alter any read/write rights as needed. You might activate compression, encryption inside the Solaris 11 VM ...

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• Memories about Tadeusz Golonka

  - by Damian

  Today at 10:55 AM, Tadeusz Golonka - my greatest  Mentor and Teacher  passed away. I had te opportunity to met Tadek in person several times last years. It was always a great experience to see how he shared his energy and passion. I was always impressed and had a lot of new ideas after such meeting or lecture. I can remember the meeting  in early 2009 and his briliant speech he did for us, the MVP community in Poland. We spent two days together and he talked to us all the time. He gave us examples how to share IT passion to other people and how to be better person for others. He was the greates Mentor I have ever met - I realized this during that meeting. My greates dream was and still is to be "like Tadek". Many Times I just went to events to see / hear him on stage ("in action"). I always wanted to have his energy, empathy and passion. Now I have to live without his good words and advices....Let me put here the words that Adam Cogan wrote on Tadek's profile on Facebook. I just can't write about that fatal accident. "The circumstances of Tadeusz Golonka death are too tragic. Tad stood up to offer his seat to an elderly lady, he lost his balance and then he slipped and hit the tram door hard. He then fell out of the tram and hit the metal barriers that separate the tram rails from the street. It was a severe accident...... So horrible.  At first it was a miracle is that he survived... he fought for several days.  My thoughts are with his lovely family. The family have asked for blood donations as a symbolic gift. Tad received a lot of blood.  Thank you Tad, you were a wonderful person. I will remember you as a kind man, a gentleman. "RIP Tadeusz- You will never ever be forgotten. You are with us all the time  

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• ZFS for Database Log Files

  - by user12620111

  I've been troubled by drop outs in CPU usage in my application server, characterized by the CPUs suddenly going from close to 90% CPU busy to almost completely CPU idle for a few seconds. Here is an example of a drop out as shown by a snippet of vmstat data taken while the application server is under a heavy workload. # vmstat 1  kthr      memory            page            disk          faults      cpu  r b w   swap  free  re  mf pi po fr de sr s3 s4 s5 s6   in   sy   cs us sy id  1 0 0 130160176 116381952 0 16 0 0 0 0  0  0  0  0  0 207377 117715 203884 70 21 9  12 0 0 130160160 116381936 0 25 0 0 0 0 0  0  0  0  0 200413 117162 197250 70 20 9  11 0 0 130160176 116381920 0 16 0 0 0 0 0  0  1  0  0 203150 119365 200249 72 21 7  8 0 0 130160176 116377808 0 19 0 0 0 0  0  0  0  0  0 169826 96144 165194 56 17 27  0 0 0 130160176 116377800 0 16 0 0 0 0  0  0  0  0  1 10245 9376 9164 2  1 97  0 0 0 130160176 116377792 0 16 0 0 0 0  0  0  0  0  2 15742 12401 14784 4 1 95  0 0 0 130160176 116377776 2 16 0 0 0 0  0  0  1  0  0 19972 17703 19612 6 2 92  14 0 0 130160176 116377696 0 16 0 0 0 0 0  0  0  0  0 202794 116793 199807 71 21 8  9 0 0 130160160 116373584 0 30 0 0 0 0  0  0 18  0  0 203123 117857 198825 69 20 11 This behavior occurred consistently while the application server was processing synthetic transactions: HTTP requests from JMeter running on an external machine. I explored many theories trying to explain the drop outs, including: Unexpected JMeter behavior Network contention Java Garbage Collection Application Server thread pool problems Connection pool problems Database transaction processing Database I/O contention Graphing the CPU %idle led to a breakthrough: Several of the drop outs were 30 seconds apart. With that insight, I went digging through the data again and looking for other outliers that were 30 seconds apart. In the database server statistics, I found spikes in the iostat "asvc_t" (average response time of disk transactions, in milliseconds) for the disk drive that was being used for the database log files. Here is an example:                     extended device statistics     r/s    w/s   kr/s   kw/s wait actv wsvc_t asvc_t  %w  %b device     0.0 2053.6    0.0 8234.3  0.0  0.2    0.0    0.1   0  24 c3t60080E5...F4F6d0s0     0.0 2162.2    0.0 8652.8  0.0  0.3    0.0    0.1   0  28 c3t60080E5...F4F6d0s0     0.0 1102.5    0.0 10012.8  0.0  4.5    0.0    4.1   0  69 c3t60080E5...F4F6d0s0     0.0   74.0    0.0 7920.6  0.0 10.0    0.0  135.1   0 100 c3t60080E5...F4F6d0s0     0.0  568.7    0.0 6674.0  0.0  6.4    0.0   11.2   0  90 c3t60080E5...F4F6d0s0     0.0 1358.0    0.0 5456.0  0.0  0.6    0.0    0.4   0  55 c3t60080E5...F4F6d0s0     0.0 1314.3    0.0 5285.2  0.0  0.7    0.0    0.5   0  70 c3t60080E5...F4F6d0s0 Here is a little more information about my database configuration: The database and application server were running on two different SPARC servers. Storage for the database was on a storage array connected via 8 gigabit Fibre Channel Data storage and log file were on different physical disk drives Reliable low latency I/O is provided by battery backed NVRAM Highly available: Two Fibre Channel links accessed via MPxIO Two Mirrored cache controllers The log file physical disks were mirrored in the storage device Database log files on a ZFS Filesystem with cutting-edge technologies, such as copy-on-write and end-to-end checksumming Why would I be getting service time spikes in my high-end storage? First, I wanted to verify that the database log disk service time spikes aligned with the application server CPU drop outs, and they did: At first, I guessed that the disk service time spikes might be related to flushing the write through cache on the storage device, but I was unable to validate that theory. After searching the WWW for a while, I decided to try using a separate log device: # zpool add ZFS-db-41 log c3t60080E500017D55C000015C150A9F8A7d0 The ZFS log device is configured in a similar manner as described above: two physical disks mirrored in the storage array. This change to the database storage configuration eliminated the application server CPU drop outs: Here is the zpool configuration: # zpool status ZFS-db-41   pool: ZFS-db-41  state: ONLINE  scan: none requested config:         NAME                                     STATE         ZFS-db-41                                ONLINE           c3t60080E5...F4F6d0  ONLINE         logs           c3t60080E5...F8A7d0  ONLINE Now, the I/O spikes look like this:                     extended device statistics                  r/s    w/s   kr/s   kw/s wait actv wsvc_t asvc_t  %w  %b device     0.0 1053.5    0.0 4234.1  0.0  0.8    0.0    0.7   0  75 c3t60080E5...F8A7d0s0                     extended device statistics                  r/s    w/s   kr/s   kw/s wait actv wsvc_t asvc_t  %w  %b device     0.0 1131.8    0.0 4555.3  0.0  0.8    0.0    0.7   0  76 c3t60080E5...F8A7d0s0                     extended device statistics                  r/s    w/s   kr/s   kw/s wait actv wsvc_t asvc_t  %w  %b device     0.0 1167.6    0.0 4682.2  0.0  0.7    0.0    0.6   0  74 c3t60080E5...F8A7d0s0     0.0  162.2    0.0 19153.9  0.0  0.7    0.0    4.2   0  12 c3t60080E5...F4F6d0s0                     extended device statistics                  r/s    w/s   kr/s   kw/s wait actv wsvc_t asvc_t  %w  %b device     0.0 1247.2    0.0 4992.6  0.0  0.7    0.0    0.6   0  71 c3t60080E5...F8A7d0s0     0.0   41.0    0.0   70.0  0.0  0.1    0.0    1.6   0   2 c3t60080E5...F4F6d0s0                     extended device statistics                  r/s    w/s   kr/s   kw/s wait actv wsvc_t asvc_t  %w  %b device     0.0 1241.3    0.0 4989.3  0.0  0.8    0.0    0.6   0  75 c3t60080E5...F8A7d0s0                     extended device statistics                  r/s    w/s   kr/s   kw/s wait actv wsvc_t asvc_t  %w  %b device     0.0 1193.2    0.0 4772.9  0.0  0.7    0.0    0.6   0  71 c3t60080E5...F8A7d0s0 We can see the steady flow of 4k writes to the ZIL device from O_SYNC database log file writes. The spikes are from flushing the transaction group. Like almost all problems that I run into, once I thoroughly understand the problem, I find that other people have documented similar experiences. Thanks to all of you who have documented alternative approaches. Saved for another day: now that the problem is obvious, I should try "zfs:zfs_immediate_write_sz" as recommended in the ZFS Evil Tuning Guide. References: The ZFS Intent Log Solaris ZFS, Synchronous Writes and the ZIL Explained ZFS Evil Tuning Guide: Cache Flushes ZFS Evil Tuning Guide: Tuning ZFS for Database Performance

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• Is SOAP Http POST more complicated than I thought

  - by Pete Petersen

  I'm currently writing a bit of code to send some xml data to a web service via HTTP POST. I thought this would be really simple and have written the following example code (C#) Console.WriteLine("Press enter to send data..."); while (Console.ReadLine() != "q") { HttpWebRequest httpWReq = (HttpWebRequest)WebRequest.Create(@"http://localhost:8888/"); Foo fooItem = new Foo { Member1 = "05", Member2 = "74455604", Member3 = "15101051", Member4 = 1, Member5 = "fsf", Member6 = 6.52, }; ASCIIEncoding encoding = new ASCIIEncoding(); string postData = fooItem.ToXml(); byte[] data = encoding.GetBytes(postData); httpWReq.Method = "POST"; httpWReq.ContentType = "application/xml"; httpWReq.ContentLength = data.Length; using (Stream stream = httpWReq.GetRequestStream()) { stream.Write(data, 0, data.Length); } HttpWebResponse response = (HttpWebResponse)httpWReq.GetResponse(); string responseString = new StreamReader(response.GetResponseStream()).ReadToEnd(); Console.WriteLine("Received " + responseString); Console.WriteLine("Press enter to send data..."); } This is all I thought would be necessary, however I have now been given the details for the web service. This included some information which is unfarmiliar to me and I'm unsure whether I need to include it. The information I was sent was <url>http://sometext/soap/rpc</url> <namespace>http://sometext/a.services</namespace> <method>receiveInfo</method> <parm-id>xmldata</parm-id> (Input data) (Actual XML data as string) <parm-id>status</parm-id> (Output data) <userid>user</userid> <password>pass</password> <secure>false</secure> I guess this means I need to include a username and password somehow, but I'm not sure what the namespace or method fields are used for. Could anyone give me a hint? Sorry I've never used webservices before.

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• Achieving decoupling in Model classes

  - by Guven

  I am trying to test-drive (or at least write unit tests) my Model classes but I noticed that my classes end up being too coupled. Since I can't break this coupling, writing unit tests is becoming harder and harder. To be more specific: Model Classes: These are the classes that hold the data in my application. They resemble pretty much the POJO (plain old Java objects), but they also have some methods. The application is not too big so I have around 15 model classes. Coupling: Just to give an example, think of a simple case of Order Header - Order Item. The header knows the item and the item knows the header (needs some information from the header for performing certain operations). Then, let's say there is the relationship between Order Item - Item Report. The item report needs the item as well. At this point, imagine writing tests for Item Report; you need have a Order Header to carry out the tests. This is a simple case with 3 classes; things get more complicated with more classes. I can come up with decoupled classes when I design algorithms, persistence layers, UI interactions, etc... but with model classes, I can't think of a way to separate them. They currently sit as one big chunk of classes that depend on each other. Here are some workarounds that I can think of: Data Generators: I have a package that generates sample data for my model classes. For example, the OrderHeaderGenerator class creates OrderHeaders with some basic data in it. I use the OrderHeaderGenerator from my ItemReport unit-tests so that I get an instance to OrderHeader class. The problem is these generators get complicated pretty fast and then I also need to test these generators; defeating the purpose a little bit. Interfaces instead of dependencies: I can come up with interfaces to get rid of the hard dependencies. For example, the OrderItem class would depend on the IOrderHeader interface. So, in my unit tests, I can easily mock the behaviour of an OrderHeader with a FakeOrderHeader class that implements the IOrderHeader interface. The problem with this approach is the complexity that the Model classes would end up having. Would you have other ideas on how to break this coupling in the model classes? Or, how to make it easier to unit-test the model classes?

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• How to become a good team player?

  - by Nick

  I've been programming (obsessively) since I was 12. I am fairly knowledgeable across the spectrum of languages out there, from assembly, to C++, to Javascript, to Haskell, Lisp, and Qi. But all of my projects have been by myself. I got my degree in chemical engineering, not CS or computer engineering, but for the first time this fall I'll be working on a large programming project with other people, and I have no clue how to prepare. I've been using Windows all of my life, but this project is going to be very unix-y, so I purchased a Mac recently in the hopes of familiarizing myself with the environment. I was fortunate to participate in a hackathon with some friends this past year -- both CS majors -- and excitingly enough, we won. But I realized as I worked with them that their workflow was very different from mine. They used Git for version control. I had never used it at the time, but I've since learned all that I can about it. They also used a lot of frameworks and libraries. I had to learn what Rails was pretty much overnight for the hackathon (on the other hand, they didn't know what lexical scoping or closures were). All of our code worked well, but they didn't understand mine, and I didn't understand theirs. I hear references to things that real programmers do on a daily basis -- unit testing, code reviews, but I only have the vaguest sense of what these are. I normally don't have many bugs in my little projects, so I have never needed a bug tracking system or tests for them. And the last thing is that it takes me a long time to understand other people's code. Variable naming conventions (that vary with each new language) are difficult (__mzkwpSomRidicAbbrev), and I find the loose coupling difficult. That's not to say I don't loosely couple things -- I think I'm quite good at it for my own work, but when I download something like the Linux kernel or the Chromium source code to look at it, I spend hours trying to figure out how all of these oddly named directories and files connect. It's a programming sin to reinvent the wheel, but I often find it's just quicker to write up the functionality myself than to spend hours dissecting some library. Obviously, people who do this for a living don't have these problems, and I'll need to get to that point myself. Question: What are some steps that I can take to begin "integrating" with everyone else? Thanks!

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• Alternatives to multiple inheritance for my architecture (NPCs in a Realtime Strategy game)?

  - by Brettetete

  Coding isn't that hard actually. The hard part is to write code that makes sense, is readable and understandable. So I want to get a better developer and create some solid architecture. So I want to do create an architecture for NPCs in a video-game. It is a Realtime Strategy game like Starcraft, Age of Empires, Command & Conquers, etc etc.. So I'll have different kinds of NPCs. A NPC can have one to many abilities (methods) of these: Build(), Farm() and Attack(). Examples: Worker can Build() and Farm() Warrior can Attack() Citizen can Build(), Farm() and Attack() Fisherman can Farm() and Attack() I hope everything is clear so far. So now I do have my NPC Types and their abilities. But lets come to the technical / programmatical aspect. What would be a good programmatic architecture for my different kinds of NPCs? Okay I could have a base class. Actually I think this is a good way to stick with the DRY principle. So I can have methods like WalkTo(x,y) in my base class since every NPC will be able to move. But now lets come to the real problem. Where do I implement my abilities? (remember: Build(), Farm() and Attack()) Since the abilities will consists of the same logic it would be annoying / break DRY principle to implement them for each NPC (Worker,Warrior, ..). Okay I could implement the abilities within the base class. This would require some kind of logic that verifies if a NPC can use ability X. IsBuilder, CanBuild, .. I think it is clear what I want to express. But I don't feel very well with this idea. This sounds like a bloated base class with too much functionality. I do use C# as programming language. So multiple inheritance isn't an opinion here. Means: Having extra base classes like Fisherman : Farmer, Attacker won't work.

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• Career Development: What should I learn next after Python? and Why? [closed]

  - by Josh

  Hi all I'm currently learning Python. I want to know what should I learn next out of these programming langauages: PHP Actionscript 3 Objective-C (iPhone applications) I work in the Multimedia industry and have decided to learn Python as a first programming language seriously because I would like to learn the basics of programming, to mainly write scripts at work that Automate task (eg. Edit multiple XML files quickly) At work we have a senior developer who knows Actionscript and PHP very well (although knows PHP better). We also have been developing iPhone applications for 2 weeks, Our senior developer could learn it although we have lots of work currently with PHP and Actionscript 3 type work and haven't had time or reason to pick up iOS development. Here are the reasons I want to learn each language, But I cannot decide what I'll learn next: PHP: I want to learn PHP because it will help with Web Development. PHP is very wanted by employers. Senior developer at work writes everything in it web sites, CMS etc. (including XML checks and scripts), I will learn a lot from him (once I learn the basics). However, I don't want to learn Web because you have to deal with lots of cross-browser problems. Actionscript 3: At work we are looking to put on another developer to help with online activities and very small games (using Actionscript 3.0 and Flash CS5) for (eg. First Aid Activities etc) I would like to do things that have a element of design as I'm better at Photoshop then developing. I want to be creative, I like to interact with users in a fun way. Objective-C (iPhone applications): We are a all mac office, we may get more iPhone, iPad application work(jobs) that need to be created. Work has found it nearly impossible to find good iPhone developers. I like apple products (Macs and iPhones), I would like to make my own games, applications in my spare time(if I knew how). Should I learn Actionscript first because it would be easier to learn then Objective-C? Should I learn PHP because it is very widely used? Should I learn Objective-C because it is really wanted by employers now?

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