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• Speaking in Sweden in April

  - by Fabrice Marguerie

  As this is my first post in 2011, I wish you all the best for this new year. I don't know for you, but it will be a year of changes for me. I'll tell you more about that when the time comes. For the time being, I just wanted to announce my next speaking engagement: I'll be presenting at SDC2011, the Scandinavian Developer Conference. This event will take place on April 4 and 5 in Göteborg, Sweden. My session will be based on my article about memory leaks: How to detect and avoid memory and resources leaks in .NET applicationsDuring this session we will analyze the most common leak sources in .NET applications and we will see how to detect them in practice. We will demonstrate with live examples several tools that can help you to troubleshoot your applications. The goal of this session is to help you fix and avoid leaks in your .NET applications, whether they are built with Windows Forms, WPF, Silverlight, ASP.NET, or as console or Windows services. You will also get advices on how to improve your applications so they become less greedy. I hope to see you there if you're around in April :-)

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• Conflict resolution for two-way sync

  - by K.Steff

  How do you manage two-way synchronization between a 'main' database server and many 'secondary' servers, in particular conflict resolution, assuming a connection is not always available? For example, I have an mobile app that uses CoreData as the 'database' on the iOS and I'd like to allow users to edit the contents without Internet connection. In the same time, this information is available on a website the devices will connect to. What do I do if/when the data on the two DB servers is in conflict? (I refer to CoreData as a DB server, though I am aware it is something slightly different.) Are there any general strategies for dealing with this sort of issue? These are the options I can think of: 1. Always use the client-side data as higher-priority 2. Same for server-side 3. Try to resolve conflicts by marking each field's edit timestamp and taking the latest edit Though I'm certain the 3rd option will open room for some devastating data corruption. I'm aware that the CAP theorem concerns this, but I only want eventual consistency, so it doesn't rule it out completely, right? Related question: Best practice patterns for two-way data synchronization. The second answer to this question says it probably can't be done.

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• Large enterprise application - clients wish to use duplicate e-mails addresses?

  - by Alex Key

  I'd like to know people's opinions, reactions to clients and technical work arounds (if applicable), to the issue of an enterprise application where a client wishes to use duplicate e-mail addresses? To clarify, when I say duplicate e-mail addresses I mean within the same client system, having multiple users that have the same e-mail address. So not just using generic e-mail addresses but using the e-mail address of another user. e.g. Bob Jenkins: [email protected] James Jeffery: [email protected] Context To give this some further context, in the e-learning sector it is common that although all staff in an organisation must complete e-learning - they may not have their own e-mail address so they choose to use their managers e-mail address. Albeit against good practice in public sites... it's a requirement we've over and over again where an organisation is split between office based staff and perhaps e.g. staff in a warehouse. Where problem lies Mr Steak, good point, the problem lies in password resets and perhaps in situations where semi-personal information could be sent (not confidential enough to worry about the insecurities of email). Perhaps reminders for specific system actions, which would be confusing for the unintended party to see (if perhaps misreading the e-mail's intended recipient) Possible solutions System knowing the difference between a "for the attention of" and direct to the person e-mails, including this in the body text. Using alternative communication such as SMS Simply not having e-mails sent to people who are not the intended recipient. Providing an e-mail service ourselfs (not really viable for a corporate IT dept) Thoughts?

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• Java Embedded @ JavaOne

  - by Tori Wieldt

  Developers, tell your manager (or the other half of your developer-entrepreneur self) about this new event being held Wednesday, Oct. 3th and Thursday, Oct. 4th in San Francisco at the Hotel Nikko (during JavaOne).Java Embedded @ JavaOne is designed to provide business and technical decision makers, as well as Java embedded ecosystem partners, a unique occasion to come together and learn about how they can use Java Embedded technologies for new business opportunities. The ideal audience for this event is business and technical decision makers (e.g. System Integrators, CTO, CXO, Chief Architects/Architects, Business Development Managers, Project Managers, Purchasing managers, Technical Leads, Senior Decision Makers, Practice Leads, R&D Heads, and Development Managers/Leads).A call for papers has gone out, but is ONLY for business-focused submissions. Event organizers are looking for best practices, case studies and panel discussions on emerging opportunities in the Java embedded space. Please consider submitting a paper. The deadline for submission is July 18.Attendees of both JavaOne and Oracle Openworld can attend Java Embedded @ JavaOne by purchasing a $100.00 USD upgrade to their full conference pass. Rates for attending Embedded @ JavaOne alone are here.

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• Get Unlimited Oracle Training for Your Team for an Entire Year

  - by KJones

  Written By Amit Kumar, Senior Director Oracle University Digital Training  Oracle University has been in the training business for a long time (over 30 years!) and has worked with many Oracle customers over the years.  We understand that getting your teams trained on the latest Oracle technologies is not always easy. Training becomes more challenging when you have remote teams, team members with different skill levels or experienced team members who just need the content that covers the latest product features. It can also be challenging to predict your training needs for the year, making it all the more difficult to provide training in a timely manner. Oracle Unlimited Learning Subscription is the Answer We’ve listened to our customers and we’ve worked hard to put together a flexible training solution that enables team members to get the training that addresses their individual needs, right when they need it. This new Oracle Unlimited Learning Subscription provides teams with one year of unlimited access to: •    All of Oracle's Training On Demand video courses for in-depth product training •    All of Oracle's Learning Streams, which provide fresh product content from Oracle experts for continuous learning •    Live connections with Oracle's top instructors  •    Dedicated labs for hands-on practice The Oracle Unlimited Learning Subscription is 100% digital, giving you maximum flexibility. It simplifies how you plan and budget for your team training.  Learning Oracle and staying connected with Oracle really has never been easier. Take a tour and contact your Oracle University representative today to learn more and request a demo. 

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• Java Embedded @ JavaOne

  - by Tori Wieldt

  Developers, tell your manager (or the other half of your developer-entrepreneur self) about this new event being held Wednesday, Oct. 3th and Thursday, Oct. 4th in San Francisco at the Hotel Nikko (during JavaOne).Java Embedded @ JavaOne is designed to provide business and technical decision makers, as well as Java embedded ecosystem partners, a unique occasion to come together and learn about how they can use Java Embedded technologies for new business opportunities. The ideal audience for this event is business and technical decision makers (e.g. System Integrators, CTO, CXO, Chief Architects/Architects, Business Development Managers, Project Managers, Purchasing managers, Technical Leads, Senior Decision Makers, Practice Leads, R&D Heads, and Development Managers/Leads).A call for papers has gone out, but is ONLY for business-focused submissions. Event organizers are looking for best practices, case studies and panel discussions on emerging opportunities in the Java embedded space. Please consider submitting a paper. The deadline for submission is July 18.Attendees of both JavaOne and Oracle Openworld can attend Java Embedded @ JavaOne by purchasing a $100.00 USD upgrade to their full conference pass. Rates for attending Embedded @ JavaOne alone are here.

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• Is learning how to use C (or C++) a requirement in order to be a good (excellent) programmer?

  - by blueberryfields

  When I first started to learn how to program, real programmers could write assembly in their sleep. Any serious schooling in computer science would include a hefty bit of training and practice in programming using assembly. That has since changed, to the point where I see Computer Science degrees with assembly, if included at all, is relegated to one assignment, and one chapter, for a total of two weeks' work out of 4 years' schooling. C/C++ programming seems to have followed a similar path. I'm no longer surprised to interview university graduates who have not spent more than two weeks programming in C++, and have only read of C in a book somewhere. While the most serious CS degrees still seem to include significant time learning and using one or both of the languages, the trend is clearly towards less enforced C/C++ in school. It's clearly possible to make a career producing good work without ever reading or writing a single line of C or C++ code. Given all of that, is learning the two languages worth the effort? Are they at all required to excel? (beyond the obvious, non-language specific advice, such as "a good selection of languages is probably important for a comprehensive education", and "it's probably a good idea to keep trying out and learning new languages throughout a programmers' career, just to stretch the gray cells")

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• SEO - different data with same title and keywords

  - by Junaid Saeed

  here is my scenario i have a website where i redirect my users basing upon the device they were using, lets say a user is visiting from an iPad, i take him directly to the page of iPad wallpapers, the user selects iPad version & i take the user to the gallery of wallpapers where the user can select & download any wallpaper. Every wallpaper is the required resolution, i have my reasons for doing this, now the thing is there are diff. resolution. versions of an image appearing one 5 diff. sections of my website, each having their own view page Now there is only one record in db.table for the image, and basing on the my consistent naming convention of the images, i pick the required image. this means when 5 different pages are generated in 5 categorized sections of the website, due to a shared DB record, the keywords, the titles and every single detail of the 5 pages is same besides the resolution of the image, and the section specific details that the page has and yeah the pages also have different paths like wallpapers.com\ipad-1\cars\Ferrari-dino.html wallpapers.com\ipad-2\cars\Ferrari-dino.html wallpapers.com\ipad-3\cars\Ferrari-dino.html wallpapers.com\ipad-4\cars\Ferrari-dino.html wallpapers.com\ipad-5\cars\Ferrari-dino.html now this is my scenario, How do Search Engines see it and how do they rank it? Is it a Good or Normal or Bad SEO practice? If bad how dangerous it is for my sites SEO? i need your comments on my scenario.

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• GeoTrust SSL brand name used by re-sellers

  - by Christopher

  I feel like a I got the bait-and-switch from my web host provider since they advertise "GeoTrust SSL" for $99. I purchased it, thinking the certificate is issued from geotrust.com, but then I get an email from Comodo saying they are providing it. My host provider says they get a discount by using Comodo. I purchased the certificate with the understanding it would be issued by GeoTrust. I called the host provider and they said they usually expect it from GeoTrust, but someone from email support responded saying the product name is "GeoTrust SSL" but they use Comodo to get a discount. I think this is bogus and unfair trade practice. However, searching for "GeoTrust" on google brings up a ton of websites selling "GeoTrust" certificates. How can companies get away with this? Since the host provider is part of BBB I plan to inform my host to update the purchase page on their website to state clearly that... "This certicate is provided at a discount and may be issued by a provider other than GeoTrust.com, such as Comodo.com" Any feedback on this is appreciated.

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• Enforcing Constraints Upon Data Documents of Various Formats

  - by Christopher Berman

  This seems like the sort of problem that must have been solved elegantly long ago, but I haven't the foggiest how to google it and find it. Suppose you're maintaining a large legacy system, which has a large collection of data (tens of GB) of various formats, including XML and two different internal configuration formats. Suppose further that there are abstract rules governing the values these files may or may not contain. EXAMPLE: File A defines the raw, mathematical data pertaining to the aerodynamics of a car for consumption of the physics component of the system. File B contains certain values from File A in an easily accessible, XML hierarchy for consumption of a different component of the system. There exists, therefore, an abstract rule (or constraint) such that the values from File B must match the values from File A. This is probably the simplest constraint that can be specified, but in practice, the constraints between files can become very complicated indeed. What is the best method for managing these constraints between files of arbitrary formats, short of migrating it over to an RDBMS (which simply isn't feasible for the foreseeable future)? Has this problem been solved already? To be more specific, I would expect the solution to at least produce notifications of violated constraints; the solution need not resolve the constraints. ============================== Sample file structures File A (JeepWrangler2011.emv): MODEL JeepWrangler2011 { EsotericMathValueX 11.1 EsotericMathValueY 22.2 EsotericMathValueZ 33.3 } File B (JeepWrangler2011.xml): <model name="JeepWrangler2011"> <!--These values must correspond File A's EsotericMathValues--> <modelExtent x="11.1" y="22.2" z="33.3"/> [...] </model>

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• What are some good seminar topics that can be used to improve designer&developer communication?

  - by tactoth

  Hello guys the thing I'll tell is what happens in the company I work for but I know it's more like a common issue in software companies. I'm development team leader in a internet service company that provides service that's very similar to dropbox. In our company we have mainly two divisions: the tech division and the designers division, both have their own reporting hierarchy. Designers focus on designing UI and prioritizing features, while developers focus on implement designers' ideas (more like being driven as our big boss has said). Then here comes our issue: the DEV team and DES team communicate very bad. DEV complain DES for these reasons: Too frequent changing of requirements Too complicated interaction (our DEV team has actually learned many HCI principles) Documents for design are incomplete, usually you just get 'design principles' and it's up to DEV to complete design details. When you find design defects, you ask DES team to resolve them, then DES team quickly change the principles and you gonna spend another several weeks because the change is so fundamental. While DES complain DEV for these reasons: Code architecture is not good enough to adapt to changing requirements (Obviously DES knows something about software development) Product design is about principles, not details. DEV fails to realize this. Communication should be quick and should be mainly oral. Trying to make most feature discussion in document for reference is too overloaded and doesn't make sense. As you can see, DEV and DES have different ideas on product design, and encourages very different practice. We have this difference because of the way we work. So our solution is that we should plan some seminars to make each part more aware of the way the other part work. Then my question is, what are some good topics for such seminars? Guessing some people may not think seminars can solve this problem, please also suggest your solution.

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• How to get feedback from the community on large chunks of code?

  - by MainMa

  Code Review.SE is great when you need feedback on a precise, short piece of code. But where to get similar feedback about the code itself when: you have thousands of LOC, don't have colleagues in your workplace ready or willing to review the code¹, don't have thousands of dollars to spend for a professional review by a third party developer?² Places like CodePlex are a good idea to get your project known³, but from what I've seen, the feedback you get on known projects are consumer feedback, i.e. concerns the bugs and feature requests, not the quality of the source code itself. What are the social way to get the community involved in the code review of the codebase of a certain size for an open source project which doesn't have the scale of Firefox or similar products? ¹ Which is the case for most personal and open source projects, or projects done in companies where the practice of regular and complete code review is nonexistent. ² Which is, again, the case for most personal and open source projects. ³ Even if too many projects published on CodePlex never get known, either because nobody cares or because they are presented not very well.

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• Are long methods always bad?

  - by wobbily_col

  So looking around earlier I noticed some comments about long methods being bad practice. I am not sure I always agree that long methods are bad (and would like opinions from others). For example I have some Django views that do a bit of processing of the objects before sending them to the view, a long method being 350 lines of code. I have my code written so that it deals with the paramaters - sorting / filtering the queryset, then bit by bit does some processing on the objects my query has returned. So the processing is mainly conditional aggregation, that has complex enough rules it can't easily be done in the database, so I have some variables declared outside the main loop then get altered during the loop. varaible_1 = 0 variable_2 = 0 for object in queryset : if object.condition_condition_a and variable_2 > 0 : variable 1+= 1 ..... ... . more conditions to alter the variables return queryset, and context So according to the theory I should factor out all the code into smaller methods, so That I have the view method as being maximum one page long. However having worked on various code bases in the past, I sometimes find it makes the code less readable, when you need to constantly jump from one method to the next figuring out all the parts of it, while keeping the outermost method in your head. I find that having a long method that is well formatted, you can see the logic more easily, as it isn't getting hidden away in inner methods. I could factor out the code into smaller methods, but often there is is an inner loop being used for two or three things, so it would result in more complex code, or methods that don't do one thing but two or three (alternatively I could repeat inner loops for each task, but then there will be a performance hit). So is there a case that long methods are not always bad? Is there always a case for writing methods, when they will only be used in one place?

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• proper way to creation multiple similiar buttons/panels

  - by JayAvon

  I have the below Code which i tried to do, but it only shows(the minus/plus button) on the last GirdLayout (Intelligence stat): JButton plusButton = new JButton("+"); JButton minusButton = new JButton("-"); statStrengthGridPanel = new JPanel(new GridLayout(1,3)); statStrengthGridPanel.add(minusButton); statStrengthGridPanel.add(new JLabel("10")); statStrengthGridPanel.add(plusButton); statConstitutionGridPanel = new JPanel(new GridLayout(1,3)); statConstitutionGridPanel.add(minusButton); statConstitutionGridPanel.add(new JLabel("10")); statConstitutionGridPanel.add(plusButton); statDexterityGridPanel = new JPanel(new GridLayout(1,3)); statDexterityGridPanel.add(minusButton); statDexterityGridPanel.add(new JLabel("10")); statDexterityGridPanel.add(plusButton); statIntelligenceGridPanel = new JPanel(new GridLayout(1,3)); statIntelligenceGridPanel.add(minusButton); statIntelligenceGridPanel.add(new JLabel("10")); statIntelligenceGridPanel.add(plusButton); I know I can do something like I did for the Panel names(have multiple ones), but I did not want to do that for the Panels in the first place. I am trying to use best practice and not have my code be repetitive. Any suggestions?? The goal is to have 4 stats, to assign points to, with decrement and increment buttons(I decided against sliders). Eventually I will have them have upper and lower limits, decrement the "unused" label, and all of that good stuff, but I just want to not be repetitive. Thanks for any help.

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• Storing User-uploaded Images

  - by Nyxynyx

  What is the usual practice for handling user uploaded photos and storing them on the database and server? For a user profile image: After receiving the image file from user, rename file to <image_id>_<username> Move image to /images/userprofile Add img filename to a table users containing their profile details like first_name, last_name, age, gender, birthday For a image for a review done by user: After receiving the image file from user, rename file to <image_id>_<review_id> Move image to /images/reviews Add img filename to a table reviews containing their profile details like review_id, review_content, user_id, score. Question 1: How should I go about storing the image filenames if the user can upload multiple photos for a particular review? Serialize? Question 2: Or have another table review_images with columns review_id, image_id, image_filename just for tracking images? Will doing a JOIN when retriving the image_filename from this table slow down performance noticeably? Question 3: Should all the images be stored in a single folder? Will there be a problem when we have 100K photos in the same folder? Is there a more efficient way to go about doing this?

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• Build vs Rebuild

  - by prash

  Build means compile and link only the source files that have changed since the last build, while Rebuild means compile and link all source files regardless of whether they changed or not. Build is the normal thing to do and is faster. Sometimes the versions of project target components can get out of sync and rebuild is necessary to make the build successful. In practice, you never need to Clean. Build or Rebuild Solution builds or rebuilds all projects in the your solution, while Build or Rebuild <project name> builds or rebuilds the StartUp project. To set the StartUp project, right click on the desired project name in the Solution Explorer tab and select Set as StartUp project. The project name now appears in bold. Compile just compiles the source file currently being edited. Useful to quickly check for errors when the rest of your source files are in an incomplete state that would prevent a successful build of the entire project. Ctrl-F7 is the shortcut key for Compile. All source files that have changed are saved when you request a build/rebuild, so you don't have to save them first. When you run your executable (F5 or Ctrl-F5), Visual Studio saves all your changed source files and builds anything that changed, so you don't need to explicitly do those steps every time. This allows for quick "trial and error" debugging. Incidentally, if you like those little Visual Studio keyboard shortcuts, you can download posters of the C# and the VB.Net ones, respectively (I am personally a big fan of using keyboard shortcuts :) ).   Visual Studio 2010 http://www.microsoft.com/downloads/en/details.aspx?FamilyID=92ced922-d505-457a-8c9c-84036160639f   Visual Studio 2005 C#: http://www.microsoft.com/downloads/details.aspx?FamilyID=c15d210d-a926-46a8-a586-31f8a2e576fe&DisplayLang=en VB.NET: http://www.microsoft.com/downloads/details.aspx?FamilyID=6bb41456-9378-4746-b502-b4c5f7182203&DisplayLang=en

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• How to handle monetary values in PHP and MySql?

  - by Songo

  I've inherited a huge pile of legacy code written in PHP on top of a MySQL database. The thing I noticed is that the application uses doubles for storage and manipulation of data. Now I came across of numerous posts mentioning how double are not suited for monetary operations because of the rounding errors. However, I have yet to come across a complete solution to how monetary values should be handled in PHP code and stored in a MySQL database. Is there a best practice when it comes to handling money specifically in PHP? Things I'm looking for are: How should the data be stored in the database? column type? size? How should the data be handling in normal addition, subtraction. multiplication or division? When should I round the values? How much rounding is acceptable if any? Is there a difference between handling large monetary values and low ones? Note: A VERY simplified sample code of how I might encounter money values in everyday life: $a= $_POST['price_in_dollars']; //-->(ex: 25.06) will be read as a string should it be cast to double? $b= $_POST['discount_rate'];//-->(ex: 0.35) value will always be less than 1 $valueToBeStored= $a * $b; //--> any hint here is welcomed $valueFromDatabase= $row['price']; //--> price column in database could be double, decimal,...etc. $priceToPrint=$valueFromDatabase * 0.25; //again cast needed or not? I hope you use this sample code as a means to bring out more use cases and not to take it literally of course. Bonus Question If I'm to use an ORM such as Doctrine or PROPEL, how different will it be to use money in my code.

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• How does datomic handle "corrections"?

  - by blueberryfields

  tl;dr Rich Hickey describes datomic as a system which implicitly deals with timestamps associated with data storage from my experience, data is often imperfectly stored in systems, and on many occasions needs to retroactively be corrected (ie, often the question of "was a True on Tuesday at 12:00pm?" will have an incorrect answer stored in the database) This seems like a spot where the abstractions behind datomic might break - do they? If they don't, how does the system handle such corrections? Rich Hickey, in several of his talks, justifies the creation of datomic, and explains its benefits. His work, if I understand correctly, is motivated by core the insight that humans, when speaking about data and facts, implicitly associate some of the related context into their work(a date-time). By pushing the work required to manage the implicit date-time component of context into the database, he's created a system which is both much easier to understand, and much easier to program. This turns out to be relevant to most database programmers in practice - his work saves everyone a lot of time managing complex, hard to produce/debug/fix, time queries. However, especially in large databases, data is often damaged/incorrect (maybe it was not input correctly, maybe it eroded over time, etc...). While most database updates are insertions of new facts, and should indeed be treated that way, a non-trivial subset of the work required to manage time-queries has to do with retroactive updates. I have yet to see any documentation which explains how such corrections, or retroactive updates, are handled by datomic; from my experience, they are a non-trivial (and incredibly difficult to deal with) subset of time-related data manipulation that database programmers are faced with. Does datomic gracefully handle such updates? If so, how?

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• Knowing state of game in real time

  - by evthim

  I'm trying to code a tic tac toe game in java and I need help figuring out how to efficiently and without freezing the program check if someone won the game. I'm only in the design stages now, I haven't started programming anything but I'm wondering how would I know at all times the state of the game and exactly when someone wins? Response to MarkR: (note: had to place comment here, it was too long for comment section) It's not a homework problem, I'm trying to get more practice programming GUI's which I've only done once as a freshman in my second introductory programming course. I understand I'll have a 2D array. I plan to have a 2D integer array where x would equal 1 and o would equal 0. However, won't it take too much time if I check after every move if someone won the game? Is there a way or a data structure or algorithm I can use so that the program will know the state (when I say state I mean not just knowing every position on the board, the int array will take care of that, I mean knowing that user 1 will win if he places x on this block) of the game at all times and thus can know automatically when someone won?

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• Estimate angle to launch missile, maths question

  - by Jonathan

  I've been working on this for an hour or two now and my maths really isn't my strong suit which is definitely not a good thing for a game programmer but that shouldn't stop me enjoying a hobby surely? After a few failed attempts I was hoping someone else out there could help so here's the situation. I'm trying to implement a bit of faked intelligence when the A.I fires it's missiles at a target in a 2D game world. By predicting the likely position the target will be in given it's current velocity and the time it will take the missile to reach it's target. I created an image to demonstrate my thinking: http://i.imgur.com/SFmU3.png which also contains the logic I use for accelerating the missile after launch. The ship that fires the missile can fire within a total of 40 degree angle, 20 either side of itself, but this could likely become variable. My current attempt was to break the space between the two lines into segments which match the targets width. Then calculate the time it would take the missile to get to that location using the formula. So for each iteration of this we total up the values and that tells us the distance travelled, ad it would then just need compared to distance to the segment. startVelocity * ((startVelocity * acceleration)^(currentframe-1) So for example. If we start at a velocity of 1f/frame with an acceleration of 0.1f the formula, at frame 4, would be 1 * (1.1^3) = 1.331 But I quickly realized I was getting lost when trying to put this into practice. Does this seem like a correct starting point or am I going completely the wrong way about it? Any pointers would help me greatly. Maths really isn't my strong suit so I get easily lost in these matters and don't even really know a good phrase to search for with this. So I guess in summary my question is more about the correct way to approach this problem and any additional code samples on top of that would be great but I'm not averse to working out the complete code from helpful pointers.

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• Are these advanced/unfair interview questions regarding Java concurrency?

  - by sparc_spread

  Here are some questions I've recently asked interviewees who say they know Java concurrency: Explain the hazard of "memory visibility" - the way the JVM can reorder certain operations on variables that are unprotected by a monitor and not declared volatile, such that one thread may not see the changes made by another thread. Usually I ask this one by showing code where this hazard is present (e.g. the NoVisibility example in Listing 3.1 from "Java Concurrency in Practice" by Goetz et al) and asking what is wrong. Explain how volatile affects not just the actual variable declared volatile, but also any changes to variables made by a thread before it changes the volatile variable. Why might you use volatile instead of synchronized? Implement a condition variable with wait() and notifyAll(). Explain why you should use notifyAll(). Explain why the condition variable should be tested with a while loop. My question is - are these appropriate or too advanced to ask someone who says they know Java concurrency? And while we're at it, do you think that someone working in Java concurrency should be expected to have an above-average knowledge of Java garbage collection?

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• Purpose oriented user accounts on a single desktop?

  - by dd_dent

  Starting point: I currently do development for Dynamics Ax, Android and an occasional dabble with Wordpress and Python. Soon, I'll start a project involving setting up WP on Google Apps Engine. Everything is, and should continue to, run from the same PC (running Linux Mint). Issue: I'm afraid of botching/bogging down my setup due to tinkering/installing multiple runtimes/IDE's/SDK's/Services, so I was thinking of using multiple users, each purposed to handle the task at hand (web, Android etc) and making each user as inert as possible to one another. What I need to know is the following: Is this a good/feasible practice? The second closest thing to this using remote desktops connections, either to computers or to VM's, which I'd rather avoid. What about switching users? Can it be made seamless? Anything else I should know? Update and clarification regarding VM's and whatnot: The reason I wish to avoid resorting to VM's is that I dislike the performance impact and sluggishness associated with it. I also suspect it might add a layer of complexity I wish to avoid. This answer by Wyatt is interesting but I think it's only partly suited for requirements (web development for example). Also, in reference to the point made about system wide installs, there is a level compromise I should accept as experessed by this for example. This option suggested by 9000 is also enticing (more than VM's actually) and by no means do I intend to "Juggle" JVMs and whatnot, partly due to the reason mentioned before. Regarding complexity, I agree and would consider what was said, only from my experience I tend to pollute my work environment with SDKs and runtimes I tried and discarded, which would occasionally leave leftovers which cause issues throught the session. What I really want is a set of well defined, non virtualized sessions from which I can choose at my leisure and be mostly (to a reasonable extent) safe from affecting each session from the other. And what I'm really asking is if and how can this be done using user accounts.

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• Best way to go for simple online multi-player games?

  - by Mr_CryptoPrime

  I want to create a trivia game for my website. The graphic design does not have to be too fancy, probably no more advanced than a typical flash game. It needs to be secure because I want users to be able to play for real money. It also needs to run fast so users don't spend their time frustrated with game freezing. Compatibility, as with almost all online products, is key because of the large target market. I am most acquainted with Java programming, but I don't want to do it in Java if there is something much better. I am assuming I will have to utilize a variety of different languages in order for everything to come together. If someone could point out the main structure of everything so I could get a good start that would be great! 1) Language choice for simple secure online multiplayer games? 2) Perhaps use a database like MySQL, stored on a secure server for the trivia questions? 3) Free educational resources and even simpler projects to practice? Any ideas or suggestions would be helpful...Thanks!

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• My Only Gripe With Programming

  - by David Espejo

  Is that im having trouble practicing problems. Even if I decide to practice the problems from my C++ book, they dont give any idea of the way the solution(program) should look like, so that I may compare to see if my program is similar in anyway. My book gives me to many generic "Write a program to do "this" " projects without really showing a concrete example of what "this" really is. In other words How Do I Know That I did "that". One problem in my book said to write a program that calculates the sales tax on a given item????? First of all slase tax differs on state(whats the state,) whats the item(a house, a dog,) How can I check this to see if im right. Programming books dont have answer keys! I know that there is no ABSOLUTE answer, thats just silly, programs can be written in many ways, but a sample of what one would look like based of the difficulty of the problem would really help! Is there a solution to this, maby a book that has worked out examples for the problems they give , or online sources that do something similar.(is there such thing as a programming book with an answer key?)

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• Want Google to index redirect urls

  - by Dave Goten

  I'm having issues with users who think that Google Search is the address bar. Some of the sites that link to my site use user friendly addresses with 301 redirects to pages that have less friendly URLs. So, for example if I enter www.foo.com/bar it goes to www.bar.com/page.php?some-parameters-and-utm-codes-etc usually this is done by a 301 redirect in order to keep the SEO from foo.com on bar.com and so on, which I believe is standard practice. However, lately there have been more and more people searching www.foo.com/bar instead of going to www.foo.com/bar directly and because the page /bar is nothing more than a redirect it has no SEO that I know of. Things I've thought of but haven't been able to test, because Google takes forever to update :) (and I'm lazy like that), include using Google sitemaps and having them enter their redirects as entries there. (I could see this working if they were the top search entry all the time, and it might appear as a sitelink, but I don't know if that'll make the url itself show up in searches) Using Canonical tags on my pages to the redirects they set up. Which is a nightmare in itself because of the nature of my pages. One week the www.foo.com/bar might go to www.bar.com/pageA.php the next it might goto www.bar.com/pageB.php and having to remember to take the canonical tag off of pageA, so that it doesn't get confused with pageB would be a pain. Using 302 redirects -.- So I guess the question here is, does anyone have any experience or knowledge about this? What should I do to make www.foo.com/bar show up when someone 'searches' for this redirect url?

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