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• An Interview with JavaOne Rock Star Martijn Verburg

  - by Janice J. Heiss

  An interview with JavaOne Rock Star Martijn Verburg, by yours truly, titled “Challenging the Diabolical Developer: A Conversation with JavaOne Rock Star Martijn Verburg,” is now up on otn/java. Verburg, one of the leading movers and shakers in the Java community, is well known for his ‘diabolical developer” talks at JavaOne where he uncovers some of the worst practices that Java developers are prone to. He mentions a few in the interview: * “A lack of communication: Software development is far more a social activity than a technical one; most projects fail because of communication issues and social dynamics, not because of a bad technical decision. Sadly, many developers never learn this lesson.* No source control: Some developers simply store code in local file systems and e-mail the code in order to integrate their changes; yes, this still happens.* Design-driven design: Some developers are inclined to cram every design pattern from the Gang of Four (GoF) book into their projects. Of course, by that stage, they've actually forgotten why they're building the software in the first place.” He points to a couple of core assumptions and confusions that lead to trouble: “One is that developers think that the JVM is a magic box that will clean up their memory and make their code run fast, as well as make them cups of coffee. The JVM does help in a lot of cases, but bad code can and will still lead to terrible results! The other trend is to try to force Java (the language) to do something it's not very good at, such as rapid Web development. So you get a proliferation of overly complex frameworks, libraries, and techniques trying to get around the fact that Java is a monolithic, statically typed, compiled, OO environment. It's not a Golden Hammer!” Verburg has many insightful things to say about how to keep a Java User Group (JUG) going, about the “Adopt a JSR” program, bugathons, and much more. Check out the article here.

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• Access functions from user control without events?

  - by BornToCode

  I have an application made with usercontrols and a function on main form that removes the previous user controls and shows the desired usercontrol centered and tweaked: public void DisplayControl(UserControl uControl) I find it much easier to make this function static or access this function by reference from the user control, like this: MainForm mainform_functions = (MainForm)Parent; mainform_functions.DisplayControl(uc_a); You probably think it's a sin to access a function in mainform, from the usercontrol, however, raising an event seems much more complex in such case - I'll give a simple example - let's say I raise an event from usercontrol_A to show usercontrol_B on mainform, so I write this: uc_a.show_uc_b+= (s,e) => { usercontrol_B uc_b = new usercontrol_B(); DisplayControl(uc_b); }; Now what if I want usercontrol_B to also have an event to show usercontrol_C? now it would look like this: uc_a.show_uc_b+= (s,e) => { usercontrol_B uc_b = new usercontrol_B(); DisplayControl(uc_b); uc_b.show_uc_c += (s2,e2) => {usercontrol_C uc_c = new usercontrol_C(); DisplayControl(uc_c);} }; THIS LOOKS AWFUL! The code is much simpler and readable when you actually access the function from the usercontrol itself, therefore I came to the conclusion that in such case it's not so terrible if I break the rules and not use events for such general function, I also think that a readable usercontrol that you need to make small adjustments for another app is preferable than a 100% 'generic' one which makes my code look like a pile of mud. What is your opinion? Am I mistaken?

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• Is there a shell-independent HUD-like menu search tool for Xfce/GNOME/Cinnamon?

  - by Redsandro

  The Ubuntu Heads-Up Display (HUD) - you love it or you hate it. Personally I rather like a classic desktop, so I use Xfce or GNOME-fork Cinnamon, and I'd like to keep those menu's where they are. But the HUD is pretty awesome when your menus are complex and you forgot where an option sits. This makes that search trick very interesting. I know the HUD is Unity specific. I am looking for a HUD-like tool to complement the menu in shells other than Unity. There is Appmenu Runner for KDE that does this. There is also appmenu-qt for KDE. Problem with the above is that it uses KDE libs, and it only works for KDE apps. This is Linux, there aught to be something like this for GNOME/GTK apps, right? Looking for any tool that can search the menus. I already use(d) Synapse, Kupfer and GNOME Do, but those are simply app-launchers (with some tricks). Something like that would suffice if only they included searching the menus for the currently focused application. The HUD allows users to activate menu items by typing part of the name. It uses a fuzzy search algorithm that will highlight partial matches. It can match menu items that are multiple layers deep in an application's menu hierarchy. The feature, which replaces traditional menu accelerators, is activated by pressing the alt key. Similar questions: Is there a way to search a menu bar in Debian? - Unix.StackExchange How can I access menu bar items alike hud (unity)? - Unix.StackExchange HUD in other window managers (especially xmonad) - AskUbuntu

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• Adding complexity by generalising: how far should you go?

  - by marcog

  Reference question: http://stackoverflow.com/questions/4303813/help-with-interview-question The above question asked to solve a problem for an NxN matrix. While there was an easy solution, I gave a more general solution to solve the more general problem for an NxM matrix. A handful of people commented that this generalisation was bad because it made the solution more complex. One such comment is voted +8. Putting aside the hard-to-explain voting effects on SO, there are two types of complexity to be considered here: Runtime complexity, i.e. how fast does the code run Code complexity, i.e. how difficult is the code to read and understand The question of runtime complexity is something that requires a better understanding of the input data today and what it might look like in the future, taking the various growth factors into account where necessary. The question of code complexity is the one I'm interested in here. By generalising the solution, we avoid having to rewrite it in the event that the constraints change. However, at the same time it can often result in complicating the code. In the reference question, the code for NxN is easy to understand for any competent programmer, but the NxM case (unless documented well) could easily confuse someone coming across the code for the first time. So, my question is this: Where should you draw the line between generalising and keeping the code easy to understand?

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• How to REALLY start thinking in terms of objects?

  - by Mr Grieves

  I work with a team of developers who all have several years of experience with languages such as C# and Java. Most of them are young enough to have been shown OOP as a standard way to develop software in university and are very comfortable with concepts such as inheritance, abstraction, encapsulation and polymorphism. Yet, many of them, and I have to include myself, still tend to create classes which are meant to be used in a very functional fashion. The resulting software is often several smaller classes which correctly represent business objects which get passed through larger classes which only supply ways to modify and use those objects (functions). Large complex difficult-to-maintain classes named Manager are usually the result of such behaviour. I can see two theoretical reasons why people might write this type of code: It's easy to start thinking of everything in terms of the database Deep down, for me, a computer handling a web request feels more like a functional operation than an object oriented operation when you think about Request Handlers, Threads, Processes, CPU Cores and CPU operations... I want source code which is easy to read and easy to modify. I have seen excellent examples of OO code which meet these objectives. How can I start writing code like this? How I can I really start thinking in an object oriented fashion? How can I share such a mentality with my colleagues?

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• Can you point me to a nontrivial strategy pattern implementation?

  - by Eugen Martynov

  We are faced implementing a registration workflow with many branches. There are three main flows which in some conditions lead to one another. Each flow has at least four different steps; some steps interact with the server, and every step adds more information to the state. Also the requirement is to have it persistent between sessions, so if the user closes the app (this is a mobile app), it will restore the process from the last completed step with the state from the previous session. I think this could benefit from the use of the strategy pattern, but I've never had to implement it for such a complex case. Does anyone know of any examples in open source or articles from which I could find inspiration? Preferably the examples would be from a live/working/stable application. I'm interested in Java implementation mostly; we are developing for Java mobile phones: android, blackberry and J2ME. We have an SDK which is quite well separated from platform specific implementations, but examples in C++, C#, Objective-C or Python would be acceptable.

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• What is Stackify?

  - by Matt Watson

  You have developers, applications, and servers. Stackify makes sure that they are all working efficiently. Our mission is to give developers the integrated tools they need to better troubleshoot and monitor the applications they create and the servers that they run on. Traditional IT operations tools are designed for network and system administrators. Developers commonly spend 30% of their time working with IT Operations remediating application service problems. Developers currently lack tools to efficiently support the applications they create. Stackify delivers the application support functionality that developers need:View application deployment locations, versions, and historyBrowse files on servers to ensure proper deploymentsAccess configuration and log files on serversRemotely restart windows services, scheduled tasks, and web applicationsBasic server monitoring and alertsCollects all application exceptions to a centralized pointLog and report on custom applications eventsStackify is building an integrated DevOps solution delivered from the cloud designed to meet the needs of developers but also help unify the working relationship with IT operations teams and existing security roles. Our goal is to help unify the interaction between developers and IT operations. Stackify allows both teams to have visibility that they never had before  to solve complex application service issues easier and faster. Stackify’s CEO and CTO both have experience managing very large and high growth software development teams. That experience is driving our design in Stackify to deliver the integrated tools we always wished we had, the next generation of development operations tools.

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• BizTalk 2009 - Scoped Record Counting in Maps

  - by StuartBrierley

  Within BizTalk there is a functoid called Record Count that will return the number of instances of a repeated record or repeated element that occur in a message instance. The input to this functoid is the record or element to be counted. As an example take the following Source schema, where the Source message has a repeated record called Box and each Box has a repeated element called Item: An instance of this Source schema may look as follows; 2 box records - one with 2 items and one with only 1 item. Our destination schema has a number of elements and a repeated box record.  The top level elements contain totals for the number of boxes and the overall number of items.  Each box record contains a single element representing the number of items in that box. Using the Record Count functoid it is easy to map the top level elements, producing the expected totals of 2 boxes and 3 items: We now need to map the total number of items per box, but how will we do this?  We have already seen that the record count functoid returns the total number of instances for the entire message, and unfortunately it does not allow you to specify a scoping parameter.  In order to acheive Scoped Record Counting we will need to make use of a combination of functoids. As you can see above, by linking to a Logical Existence functoid from the record/element to be counted we can then feed the output into a Value Mapping functoid.  Set the other Value Mapping parameter to "1" and link the output to a Cumulative Sum functoid. Set the other Cumulative Sum functoid parameter to "1" to limit the scope of the Cumulative Sum. This gives us the expected results of Items per Box of 2 and 1 respectively. I ran into this issue with a larger schema on a more complex map, but the eventual solution is still the same.  Hopefully this simplified example will act as a good reminder to me and save someone out there a few minutes of brain scratching.

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• School vs Self-Taught [duplicate]

  - by Joan Venge

  This question already has an answer here: Do I need a degree in Computer Science to get a junior Programming job? [closed] 8 answers Do you think university is a good learning environment or is it better to be autodidact? [closed] 3 answers Do you think formal education is necessary to gain strong programming skills? There are a lot of jobs that aren't programming but involves programming, such as tech artists in games, fx tds in film for example. I see similar patterns in the people I work where the best ones I have seen were self-taught, because of being artists primarily. But I also see that while the software, programming knowledge is varied and deep, hardware knowledge is very basic, including me, again due to lack of formal education. But I also work with a lot of programmers who possess both skills in general (software and hardware). Do you think it's necessary to have a formal education to have great programming skills? Would you think less of someone if he didn't have a degree in computer science, or software engineering, etc in terms of job opportunities? Would you trust him to do a software engineering job, i.e. writing a complex tool? Basically I feel the self-taught programmer doesn't know a lot of things, i.e. not knowing a particular pattern or a particular language, etc. But I find that the ability to think outside the box much more powerful. As "pure" programmers what's your take on it?

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• How to build a "traffic AI"?

  - by Lunikon

  A project I am working on right now features a lot of "traffic" in the sense of cars moving along roads, aircraft moving aroun an apron etc. As of now the available paths are precalculated, so nodes are generated automatically for crossings which themselves are interconnected by edges. When a character/agent spawns into the world it starts at some node and finds a path to a target node by means of a simply A* algorithm. The agent follows the path and ultimately reaches its destination. No problem so far. Now I need to enable the agents to avoid collisions and to handle complex traffic situations. Since I'm new to the field of AI I looked up several papers/articles on steering behavior but found them to be too low-level. My problem consists less of the actual collision avoidance (which is rather simple in this case because the agents follow strictly defined paths) but of situations like one agent leaving a dead-end while another one wants to enter exactly the same one. Or two agents meeting at a bottleneck which only allows one agent to pass at a time but both need to pass it (according to the optimal route found before) and they need to find a way to let the other one pass first. So basically the main aspect of the problem would be predicting traffic movement to avoid dead-locks. Difficult to describe, but I guess you get what I mean. Do you have any recommendations for me on where to start looking? Any papers, sample projects or similar things that could get me started? I appreciate your help!

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• Museum of Modern Art Starts Video Game Collection; Acquires Myst, Pac-Man, and More

  - by Jason Fitzpatrick

  The Museum of Modern Art is weighing in on the video-games-as-art debate by starting a collection of iconic video games and putting them up for public display. Read on to see what games are included in the initial batch and the MoMA’s reasons behind starting a video game collection. Although the MoMA is slated to grow to over 40 titles, the seed batch is 14 titles including: Pac-Man, Tetris, Sim City 2000, Myst, Portal, and Dwarf Fortress. In the announcement they explain the motivation for building a video game collection: Are video games art? They sure are, but they are also design, and a design approach is what we chose for this new foray into this universe. The games are selected as outstanding examples of interaction design—a field that MoMA has already explored and collected extensively, and one of the most important and oft-discussed expressions of contemporary design creativity. Our criteria, therefore, emphasize not only the visual quality and aesthetic experience of each game, but also the many other aspects—from the elegance of the code to the design of the player’s behavior—that pertain to interaction design. In order to develop an even stronger curatorial stance, over the past year and a half we have sought the advice of scholars, digital conservation and legal experts, historians, and critics, all of whom helped us refine not only the criteria and the wish list, but also the issues of acquisition, display, and conservation of digital artifacts that are made even more complex by the games’ interactive nature. This acquisition allows the Museum to study, preserve, and exhibit video games as part of its Architecture and Design collection. The above quote is only a small snippet of a much lengthier look at the benefits of examining and preserving video games, hit up the link below to check out the full post including future titles the MoMA would like to include in their archive. Video Games: 14 in the Collection, for Starters [Inside/Out] How To Boot Your Android Phone or Tablet Into Safe Mode HTG Explains: Does Your Android Phone Need an Antivirus? How To Use USB Drives With the Nexus 7 and Other Android Devices

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• Intelligent Conflict Detection and Resolution

  - by Doug Reid

  0 false 18 pt 18 pt 0 0 false false false /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin:0in; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:12.0pt; font-family:"Times New Roman"; mso-ascii-font-family:Cambria; mso-ascii-theme-font:minor-latin; mso-fareast-font-family:"Times New Roman"; mso-fareast-theme-font:minor-fareast; mso-hansi-font-family:Cambria; mso-hansi-theme-font:minor-latin;} Conflict Detection and Resolution in Oracle GoldenGate11gR2 has gone through a significant overhaul. The improvements that have been made to this area are substantial and will make it easier for customers to implement complex, heterogeneous GoldenGate configurations. GoldenGate has provided methods for conflict detection and resolution for a number of past releases, but at Oracle we have the opportunity to take advantage of some of the great ideas in this area. Oracle has had feature rich conflict detection and resolution framework in other products, which has been implemented in Oracle GoldenGate 11gR2. These improvements are geared toward helping customers more easily implement advanced configurations that require conflict detection and resolution by providing a robust framework for conflict detection for all DML statements and resolution via pre-built methods, all with less code and simpler syntax than in prior releases. Conflict Detection and Resolution in Oracle GoldenGate 11gR2 is available for our supported heterogeneous platforms, which includes Oracle Database, MySQL, Sybase ASE, SQL Server, and DB2 Linux, Unix, Windows, z/OS, plus DB2 on i Series, which is newly supported in this release. Additional information on the Conflict Detection and Resolution capabilities can be found in our documentation. 

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• PHP/MySQL Database application development tool

  - by RCH

  I am an amateur PHP coder, and have built a couple of dozen projects from scratch (including fairly simple e-commerce systems with user authentication, PayPal integration etc - all coded by hand from a clean page. Have also done a price comparison engine that takes data from multiple sites etc.). But I am no expert with OO and other such advanced techniques - I just have a fairly decent grasp of the basics of data processing, logic, functions and trying to optimize code as much as possible. I just want to make this clear so you have some idea of where I'm coming from. I have a couple of fairly large new projects on my plate for corporate clients - both require bespoke database-driven applications with complex relationships, many tables and lots of different front-end functions to manipulate that data for the internal staff in these companies. I figured building these systems from scratch would probably be a huge waste of time. Instead, there must be tools out there that will allow me to construct MySQL databases and build the pages with things like pagination, action buttons, table construction etc. Some kind of database abstraction layer, or system generator, if you will. What tool do you recommend for such a purpose for someone at my level? Open source would be great, but I don't mind paying for something decent as well. Thanks for any advice.

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• the OpenJDK group at Oracle is growing

  - by john.rose

  p.p1 {margin: 0.0px 0.0px 12.0px 0.0px; font: 12.0px Times} span.s1 {text-decoration: underline ; color: #0000ee} The OpenJDK software development team at Oracle is hiring. To get an idea of what we’re looking for, go to the Oracle recruitment portal and enter the Keywords “Java Platform Group” and the Location Keywords “Santa Clara”.  (We are a global engineering group based in Santa Clara.)  It’s pretty obvious what we are working on; just dive into a public OpenJDK repository or OpenJDK mailing list. Here is a typical job description from the current crop of requisitions: The Java Platform group is looking for an experienced, passionate and highly-motivated Software Engineer to join our world class development effort. Our team is responsible for delivering the Java Virtual Machine that is used by millions of developers. We are looking for a development engineer with a strong technical background and thorough understanding of the Java Virtual Machine, Java execution runtime, classloading, garbage collection, JIT compiler, serviceability and a desire to drive innovations. As a member of the software engineering division, you will take an active role in the definition and evolution of standard practices and procedures. You will be responsible for defining and developing software for tasks associated with the developing, designing and debugging of software applications or operating systems. Work is non-routine and very complex, involving the application of advanced technical/business skills in area of specialization. Leading contributor individually and as a team member, providing direction and mentoring to others. BS or MS degree or equivalent experience relevant to functional area. 7 years of software engineering or related experience.

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• Creating Parent-Child Relationships in SSRS

  - by Tim Murphy

  As I have been working on SQL Server Reporting Services reports the last couple of weeks I ran into a scenario where I needed to present a parent-child data layout.  It is rare that I have seen a report that was a simple tabular or matrix format and this report continued that trend.  I found that the processes for developing complex SSRS reports aren’t as commonly described as I would have thought.  Below I will layout the process that I went through to create a solution. I started with a List control which will contain the layout of the master (parent) information.  This allows for a main repeating report part.  The dataset for this report should include the data elements needed to be passed to the subreport as parameters.  As you can see the layout is simply text boxes that are bound to the dataset. The next step is to set a row group on the List row.  When the dialog appears select the field that you wish to group your report by.  A good example in this case would be the employee name or ID. Create a second report which becomes the subreport.  The example below has a matrix control.  Create the report as you would any parameter driven document by parameterizing the dataset. Add the subreport to the main report inside the row of the List control.  This can be accomplished by either dragging the report from the solution explorer or inserting a Subreport control and then setting the report name property. The last step is to set the parameters on the subreport.  In this case the subreport has EmpId and ReportYear as parameters.  While some of the documentation on this states that the dialog will automatically detect the child parameters, but this has not been my experience.  You must make sure that the names match exactly.  Tie the name of the parameter to either a field in the dataset or a parameter of the parent report. del.icio.us Tags: SQL Server Reporting Services,SSRS,SQL Server,Subreports

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• Desktop application, dependency injection

  - by liori

  I am thinking of applying a real dependency injection library to my toy C#/GTK# desktop application. I chose NInject, but I think this is irrelevant to my question. There is a database object, a main window and several utility window classes. It's clear that I can inject the database into every window object, so here DI is useful. But does it make sense to inject utility window classes into other window classes? Example: I have classes such as: class MainWindow {…} class AddItemWindow {…} class AddAttachmentWindow {…} class BrowseItemsWindow {…} class QueryBuilderWindow {…} class QueryBrowserWindow {…} class PreferencesWindow {…} … Each of the utility classes can be opened from MainWindow. Some utility windows can also be opened from other utility windows. Generally, there might be a really complex graph of who can open whom. So each of those classes might need quite a lot of other window classes injected. I'm worried that such usage will go against the suggestion not to inject too many classes at once and become a code smell. Should I use some kind of a service locator object here?

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• How to Transfer All Your Information to a New PS3

  - by Justin Garrison

  The PlayStation 3 now costs half the price, has double the storage, and uses half the power. If you need another reason to upgrade, Sony also makes it easy to transfer all of your information to a new console. Transferring all of your games, data, and settings is easier than ever, and all you need is an ethernet cable. Read on as we walk you through the whole process of setting up your new PS3 and wiping all your information off the old one. Latest Features How-To Geek ETC Learn To Adjust Contrast Like a Pro in Photoshop, GIMP, and Paint.NET Have You Ever Wondered How Your Operating System Got Its Name? Should You Delete Windows 7 Service Pack Backup Files to Save Space? What Can Super Mario Teach Us About Graphics Technology? Windows 7 Service Pack 1 is Released: But Should You Install It? How To Make Hundreds of Complex Photo Edits in Seconds With Photoshop Actions Hack Apart a Highlighter to Create UV-Reactive Flowers [Science] Add a “Textmate Style” Lightweight Text Editor with Dropbox Syncing to Chrome and Iron Is the Forcefield Really On or Not? [Star Wars Parody Video] Google Updates Picasa Web Albums; Emphasis on Sharing and Showcasing Uwall.tv Turns YouTube into a Video Jukebox Early Morning Sunrise at the Beach Wallpaper

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• How do you explain to an "agile" team that they still need to plan the software they write?

  - by user23157

  This week at work I got agiled yet again. Having gone through the standard agile, TDD, shared ownership, ad hoc development methodology of never planning anything beyond a few user stories on a piece of card, verbally chewing the cud over the technicallities of a 3rd party integration ad nauseam without ever doing any real thinking or due dilligence and architecturally coupling all production code to the first test that comes into anyone's head for the past few months we reach the end of a release cycle and lo and behold the main externally visible feature that we have been developing is too slow to use, buggy, becoming labyrinthinly complex and completely inflexible. During this process "spikes" were done but never documented and not a single architectural design was ever produced (there was no FS, so what the hell eh, if you don't know what you are developing, how can you plan or research it?) - the project passed from pair to pair, each of whom only ever focused on a single user story at a time and well the result was inevitable. To resolve this I went off the radar, went (the dreaded) waterfall, planned, coded and basically didn't swap off the pair and tried as much as I could to work alone - focusing on solid architecture and specifications rather than unit tests which will come later once everything is pinned down. The code is now much better and is actually totally usable, flexible and fast. Certain people seem to have really resented me doing this and have gone out of their way to sabotage my efforts (possibly unconsciously) because it goes against the holy process of agile. So how do you, as a developer, explain to the team that it is not "un-agile" to plan their work, and how do you fit planning into the agile process? (I'm not talking about the IPM; I'm talking about sitting down with a problem and sketching out an end-to-end design that says how a problem should be solved in sufficient detail that anyone who works on the problem knows what architecture and patterns they should be using and where the new code should integrate into existing code)

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• Finding most Important Node(s) in a Directed Graph

  - by Srikar Appal

  I have a large (˜ 20 million nodes) directed Graph with in-edges & out-edges. I want to figure out which parts of of the graph deserve the most attention. Often most of the graph is boring, or at least it is already well understood. The way I am defining "attention" is by the concept of "connectedness" i.e. How can i find the most connected node(s) in the graph? In what follows, One can assume that nodes by themselves have no score, the edges have no weight & they are either connected or not. This website suggest some pretty complicated procedures like n-dimensional space, Eigen Vectors, graph centrality concepts, pageRank etc. Is this problem that complex? Can I not do a simple Breadth-First Traversal of the entire graph where at each node I figure out a way to find the number of in-edges. The node with most in-edges is the most important node in the graph. Am I missing something here?

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• Can Clojure's thread-based agents handle c10k performance?

  - by elliot42

  I'm writing a c10k-style service and am trying to evaluate Clojure's performance. Can Clojure agents handle this scale of concurrency with its thread-based agents? Other high performance systems seem to be moving towards async-IO/events/greenlets, albeit at a seemingly higher complexity cost. Suppose there are 10,000 clients connected, sending messages that should be appended to 1,000 local files--the Clojure service is trying to write to as many files in parallel as it can, while not letting any two separate requests mangle the same single file by writing at the same time. Clojure agents are extremely elegant conceptually--they would allow separate files to be written independently and asynchronously, while serializing (in the database sense) multiple requests to write to the same file. My understanding is that agents work by starting a thread for each operation (assume we are IO-bound and using send-off)--so in this case is it correct that it would start 1,000+ threads? Can current-day systems handle this number of threads efficiently? Most of them should be IO-bound and sleeping most of the time, but I presume there would still be a context-switching penalty that is theoretically higher than async-IO/event-based systems (e.g. Erlang, Go, node.js). If the Clojure solution can handle the performance, it seems like the most elegant thing to code. However if it can't handle the performance then something like Erlang or Go's lightweight processes might be preferable, since they are designed to have tens of thousands of them spawned at once, and are only moderately more complex to implement. Has anyone approached this problem in Clojure or compared to these other platforms? (Thanks for your thoughts!)

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• Prepared statement alternatives for this middle-man program?

  - by user2813274

  I have an program that is using a prepared statement to connect and write to a database working nicely, and now need to create a middle-man program to insert between this program and the database. This middle-man program will actually write to multiple databases and handle any errors and connection issues. I would like advice as to how to replicate the prepared statements such as to create minimal impact to the existing program, however I am not sure where to start. I have thought about creating a "SQL statement class" that mimics the prepared statement, only that seems silly. The existing program is in Java, although it's going to be networked anyways so I would be open to writing it in just about anything that would make sense. The databases are currently MySQL, although I would like to be open to changing the database type in the future. My main question is what should the interface for this program look like, and does doing this even make sense? A distributed DB would be the ideal solution, but they seem overly complex and expensive for my needs. I am hoping to replicate the main functionality of a distributed DB via this middle-man. I am not too familiar with sql-based servers distributing data (or database in general...) - perhaps I am fighting an uphill battle by trying to solve it via programming, but I would like to make an attempt at least.

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• Generalist Languages: Dying or Alive and Well?

  - by dsimcha

  Around here, it seems like there's somewhat of a consensus that generalist programming languages (that try to be good at everything, support multiple paradigms, support both very high- and very low-level programming), etc. are a bad idea, and that it's better to pick the right tool for the job and use lots of different languages. I see three major areas where this is flawed: Interfacing multiple languages is always at least a source of friction and is sometimes practically impossible. How severe a problem this is depends on how fine-grained the interfacing is. Near the boundary between the two languages, though, you're basically limited to the intersection of their features, and you have to care about things like binary interfaces that you usually wouldn't. Passing complex data structures (i.e. not just primitives and arrays of primitives) between languages is almost always a hassle. Furthermore, shifting between different syntaxes, different conventions, etc. can be confusing and annoying, though this is a fairly minor complaint. Requirements are never set in stone. I hate picking a language thinking it's the right tool for the job, then realizing that, when some new requirement surfaces, it's actually a terrible choice for that requirement. This has happened to me several times before, usually when working with languages that are very slow, very domain specific and/or has very poor concurrency/parallelism support. When you program in a language for a while, you start to build up a personal toolbox of small utility functions/classes/programs. The value of these goes drastically down if you're forced to use a different language than the one you've accumulated all this code in. What am I missing here? Why shouldn't more focus be placed on generalist languages? Are generalist languages as a category dying or alive and well?

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• Complexity of defense AI

  - by Fredrik Johansson

  I have a non-released game, and currently it's only possible to play with another human being. As the game rules are made up by me, I think it would be great if new players could learn basic game play by playing against an AI opponent. I mean it's not like Tennis, where the majority knows at least the fundamental rules. On the other hand, I'm a bit concerned that this AI implementation can be quite complex. I hope you can help me with an complexity estimation. I've tried to summarize the gameplay below. Is this defense AI very hard to do? Basic Defense Game Play Player Defender can move within his land, i.e. inside a random, non-convex, polygon. This land will also contain obstacles modeled as polygons, that Defender has to move around. Player Attacker has also a land, modeled as another such polygon. Assume that Defender shall defend against Attacker. Attacker will then throw a thingy towards Defender's land. To be rewarded, Attacker wants to hit Defender's land, and Defender will want to strike away the thingy from his land before it stops to prevent Attacker from scoring. To feint Defender, Attacker might run around within his land before the throw, and based on these attacker movements Defender shall then continuously move to the best defense position within his land.

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• Data Movement and the Decision Matrix

  - by BuckWoody

  Maybe it’s my military background, or maybe I’ve always had this predilection, but I like to use two devices when I need to make a complex decision: A checklist and a decision matrix. I like to use a checklist because it ensures that I remember the big bits of what I need to do, and brings up questions or areas that I didn’t think about when evaluating options for the decision. And the decision matrix – that’s the thing I use to actually lay out those options. It’s simply a spreadsheet-like grid (I use Excel, but paper and pencil works as well) that lays out the requirements or advantages for the decision across the top, and the options I have on the left-hand side. Then in the “cells” I put whether or not that option on the left will meet the requirement in that column. I then simply “weight” each cell to organize the choices by best-fit. The right answer (or answers) will float right to the top. I was asked yesterday about options for moving data in SQL Server to another system. There are just dozens of ways to do this, from bcp to Replication, each with certain advantages and costs. But asking the questions for the top row first helped me show the person that it isn’t a particular technology that is important, it’s laying out those requirements and thinking about which elements are more important than the other. For instance, is it more important to have the data moved all the time, or is it OK if that happens once in a while? Does the data have to move in two directions or just one? All of these will help that answer jump right out. Try it sometime – it’s a great learning exercise, since it will force you to focus on filling out the matrix. The answer is out there, Neo. Share this post: email it! | bookmark it! | digg it! | reddit! | kick it! | live it!

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• How to explain a layperson why a developer should not be interrupted while neck-deep in coding?

  - by András Szepesházi

  If you just consider the second part of my question, "Why a developer should not be interrupted while neck-deep in coding", that has been discussed a number of times by smart people. Heck, even the co-founder of SO, Joel Spolsky, wrote a blog post about "getting in the zone" and "being knocked out of the zone" and why it takes an average of 15 minutes to achieve productivity when participating in complex, software development related tasks. So I think the why has been established. What I'm interested in is how to explain all that to somebody who doesn't know beans about Beans (khmm I mean software development). How to tell the wife, or the funny guy from accounting at the workplace, or the long time friend who pings you on Skype every 30 minutes with a "Wazzzzzzup?!", that all the interruptions have a much deeper impact on your work than the obvious 30 seconds they took from your time. Obviously you can't explain it by sentences like "I have to juggle a lot of variable names in my short term memory" unless you want to be the target of blank stares or friendly abuse. I'd like to be able to explain all that to non-developers in a way that will make them clearly understand - without being offensive, elitist or too technical. EDIT: Thanks to everyone for their great insights. I've accepted EpsilonVector's answer as his analogy was the closest one to my original needs. The "falling asleep" explanation is neither offensive nor technical, almost anyone can relate to it, and the consequences of getting disturbed while falling asleep or while being in the zone are very similar: you experience frustration and you "lose" 15-20 minutes of time.

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