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• Oracle Business Intelligence Applications 10g Bootcamp

  - by mseika

  Oracle Business Intelligence Applications 10g Bootcamp 12th - 15th February 2012, Reading (UK) The Oracle Business Intelligence Applications offer out-of-the-box integration with Siebel CRM and Oracle eBusiness Suite and provide pre-built Operational BI solutions for eBusiness Suite, Peoplesoft, Siebel, and SAP. This training will provide attendees with an in-depth working understanding of the architecture, the technical and the functional content of the Oracle Business Intelligence Applications, whilst also providing an understanding of their installation, configuration and extension. The course will cover the following topics:• Overview of Oracle Business Intelligence Applications• Oracle BI Applications Fundamentals and Features• Configuring BI Applications for Oracle E-Business Suite• Understanding BI Applications Architecture• Fundamentals of BI Applications Security REGISTER NOW Partner Registration Guide Price: FREE Cookham RoomOracle Corporation UK LtdOracle ParkwayThames Valley ParkReading, Berkshire RG6 1RA12th - 15th February 20129:30 am – 5:00 pm BST AudienceThe seminar is aimed at BI Consultants and Implementation Consultants within Oracle's Gold and Platinum Partners. Prerequisites• Good understanding of basic data warehousing concepts• Hands on experience in Oracle Business Intelligence Enterprise Edition• Hands on experience in Informatica• Some understanding of Oracle BI Applications is required (See Sales & Technical Tutorials for OBI, BI-Apps and Hyperion EPM) • Good understanding of any of the following Oracle EBS modules: General Ledger, Accounts Receivables, Accounts Payables System Requirements Please note that attendees are required to have a laptop. Laptop• 4GB RAM-Recognized by Windows 64 bits• 80GB free space in Hard drive or External Device• CPU Core 2 Duo or HigherOperating System Requirements• Windows 7, Windows XP, Windows 2003• NOT ALLOWED with Windows Vista• An Administrator User For more information please contact [email protected].

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• Android Card Game Database for Deck Building

  - by Singularity222

  I am making a card game for Android where a player can choose from a selection of cards to build a deck that would contain around 60 cards. Currently, I have the entire database of cards created that the user can browse. The next step is allowing the user to select cards and create a deck with whatever cards they would like. I have a form where the user can search for specific cards based off a few different attributes. The search results are displayed in a List Activity. My thought about deck creation is to add the primary key of each card the user selects to a SQLite Database table with the amount they would like in the deck. This way as the user performs searches for cards they can see the state of the deck. Once the user decides to save the deck. I'll export the card list to XML and wipe the contents of the table. If the user wanted to make changes to the deck, they would load it, it would be parsed back into the table so they could make the changes. A similar situation would occur when the eventually load the deck to play a game. I'm just curious what the rest of you may think of this method. Currently, this is a personal project and I am the only one working on it. If I can figure out the best implementation before I even begin coding I'm hoping to save myself some time and trouble.

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• Code &amp; Slides &ndash; SDE &ndash; What&rsquo;s new in Silverlight 4

  - by Timmy Kokke

  Last Tuesday the Software Developers Network – SDN organized another SDE. I’ve had the opportunity to present a session about Silverlight 4. I talked about lots of new features in Silverlight 4 and Expression Blend 4, focused on the Out-Of-Browser features.     The slides of my presentation can be downloaded here.   In my presentation I demonstrated a couple of features from my new pet project “SilverAmp”. This project is based on the legendary WinAmp, but made entirely in Silverlight. I use it to try out many new Silverlight 4 features. It’s not finished yet, but useful already. It runs outside the browser with elevated trust. It reads your local MyMusic folder and uses the TagLib library to read the ID3 tags of the mp3s it finds. SilverAmp is using MEF for extensibility. It uses a custom Window Chrome, designed in Expression Design. And it shows a notification window when a new song starts to play.   In the future it is going to get song information from Last.FM, will be able to show YouTube videos inside itself and it will tweet about what you are playing. The project will be fully documented to function as a reference implementation for the new Silverlight 4 features.   You can download the source on  http://SilverAmp.codeplex.com   Below are two screenshot of SilverAmp.                     If you have any questions, comments,  issues or feature requests let me know.

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• Rope Colliding with a Rectangle

  - by Colton

  I have my rope, and I have my rectangles. The rope is similar to the implementation found here: http://nehe.gamedev.net/tutorial/rope_physics/17006/ Now, I want to make the rope properly collide with the rectangle such that the rope will not pass through a rectangle, and wrap around the rectangle and all that good stuff. Currently, I have it set so no rope node can pass through a rect (successfully), however, this means a rope segment can still pass through a block. Ex: So the question is, what can I do to fix this? What I have tried: I create a rectangle between two nodes of a rope, calculate rotation between the nodes, and get myself a transformed rectangle. I can successfully detect a collision between rope segments and a (non-transformed) rectangle. Create a new node or pivot point around the corner of the block, and rearrange nodes to point to the corner node. Trouble is determining what corner the rope segment is passing through. And then the current rope setup goes wonky (based on verlet integration, so a sudden change in position causes the rope to wiggle like a seismograph during a magnitude 8 earth quake.) Among other issues that might be solvable, but its turning into a case by case thing, which doesn't seem right. I think the best answer here would just be a link to a tutorial (I simply can't find any, most lead to box2D or farseer, but I want to at least learn how it works before I hide behind an engine).

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• Algorithms or patterns for a linked question and answer cost calculator

  - by kmc

  I've been asked to build an online calculator in PHP (and the Laravel framework). It will take the answers to a series of questions to estimate the cost of a home extension. For example, a couple of questions may be: What is the lie of your property? Flat, slightly inclined, heavily inclined. (these suggestive values could have specific values in the underlying calculator like, 0 degrees, 5 degrees, 10 degrees. What is your current flooring system? Wooden, or concrete? These would then impact the results of other questions. Once the size of the extension has been input, the lie of the land will affect how much site works will cost, and how much rubbish collection will cost. The second question will impact the cost of the extensions flooring, as stumping and laying floorboards is a different cost to laying foundations and a concrete slab. It will also influence what heating and cooling systems are available in the calculator. So it's VERY interlinked. The answer to any question can influence the options of other questions, and the end result. I'm having trouble figuring out an approach to this that will allow new options and questions to be plugged in at a later stage without having things too coupled. The Observer pattern, or Laravel's events may be handy, but currently the sheer breadth of the calculator has me struggling to gather my thoughts and see a sensible implementation. Are there any patterns or OO approaches that may help? Thanks!

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• Should I use an interface when methods are only similar?

  - by Joshua Harris

  I was posed with the idea of creating an object that checks if a point will collide with a line: public class PointAndLineSegmentCollisionDetector { public void Collides(Point p, LineSegment s) { // ... } } This made me think that if I decided to create a Box object, then I would need a PointAndBoxCollisionDetector and a LineSegmentAndBoxCollisionDetector. I might even realize that I should have a BoxAndBoxCollisionDetector and a LineSegmentAndLineSegmentCollisionDetector. And, when I add new objects that can collide I would need to add even more of these. But, they all have a Collides method, so everything I learned about abstraction is telling me, "Make an interface." public interface CollisionDetector { public void Collides(Spatial s1, Spatial s2); } But now I have a function that only detects some abstract class or interface that is used by Point, LineSegment, Box, etc.. So if I did this then each implementation would have to to a type check to make sure that the types are the appropriate type because the collision algorithm is different for each different type match up. Another solution could be this: public class CollisionDetector { public void Collides(Point p, LineSegment s) { ... } public void Collides(LineSegment s, Box b) { ... } public void Collides(Point p, Box b) { ... } // ... } But, this could end up being a huge class that seems unwieldy, although it would have simplicity in that it is only a bunch of Collide methods. This is similar to C#'s Convert class. Which is nice because it is large, but it is simple to understand how it works. This seems to be the better solution, but I thought I should open it for discussion as a wiki to get other opinions.

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• Do we have enough time to build an electric car future?

  - by julien.groues

  A recent article from Greenbang has posed the question 'Do we have enough time to build an electric car future?'. The writer discusses that, although the future of transport might lie with electric cars, there is concern regarding whether we'll be able to build the market and infrastructure required to support them, before carbon and oil constraints create difficulties in powering the vehicles. Of course, the increasing use of Electric vehicles (EVs) is going to put excessive pressure on energy grids, as large volumes of electricity will need to be directed to charging points, which in turn must handle fluctuating demand at peak times. EVs are increasing in popularity as a sustainable method of transport to reduce carbon consumption, and electric utilities will have the opportunity, and the challenge, to quickly determine the best methods to fuel these vehicles and accommodate the associated increases in demand for energy. Critically, efficient software is required to provide diagnostic and predictive capabilities related to EV refuelling - for example, anticipated electricity flow will need to be addressed as the number of EVs on the road increases, and electricity will need to be directed to specific areas on-demand as vehicles attempt to recharge en-mass. But a smart grid infrastructure can meet these demands, intelligently. The implementation of a smart grid is not in the distant future, it is an achievable reality for utilities via simple installation of new software and technologies, which can be done incrementally for those facing existing legacy systems or concerned with upfront costs. The smart grid is integral to the monitoring and control of energy use as well as the future-proofing of the energy grid. A smart grid will be critical to meeting the electricity requirements of new EVs and will ensure their successful deployment by providing a reliable foundation for the data handling required to record and manage electricity distribution - from recording and assessing energy usage, to analysing data and sharing information with consumers via green billing. http://www.greenbang.com/do-we-have-enough-time-to-build-an-electric-car-future_14248.html

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• Using a permutation table for simplex noise without storing it

  - by J. C. Leitão

  Generating Simplex noise requires a permutation table for randomisation (e.g. see this question or this example). In some applications, we need to persist the state of the permutation table. This can be done by creating the table, e.g. using def permutation_table(seed): table_size = 2**10 # arbitrary for this question l = range(1, table_size + 1) random.seed(seed) # ensures the same shuffle for a given seed random.shuffle(l) return l + l # see shared link why l + l; is a detail and storing it. Can we avoid storing the full table by generating the required elements every time they are required? Specifically, currently I store the table and call it using table[i] (table is a list). Can I avoid storing it by having a function that computes the element i, e.g. get_table_element(seed, i). I'm aware that cryptography already solved this problem using block cyphers, however, I found it too complex to go deep and implement a block cypher. Does anyone knows a simple implementation of a block cypher to this problem?

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• Website Ethics / legal issues, image copyrights

  - by RailsN00b

  Ignoring the technical implementation of a website for a second, assume a website that is similar to twitter but with pictures. A user say something and puts a picture of whatever they said. As the nature of the internet, the images will most likely not be his/hers image. There are 2 options that I see for dealing with this: 1. The user will post a URL of the picture and the website will pull the picture from that URL everytime someone enters that page 2. The website will save the image in its own database of images and display the image to the visitors 'locally' The problem with option #1, while it saved storage, I see an issue with 'stealing' other websites bandwidth and if my website has many many visitors it could cost the image-hosting websites a lot and possible even crash it if the server can't handle the load. The problem with opion #2, while it saves the load to other websites, it practically takes pictures that could have copyright on them. Which option is better to implement in terms of legal issues and ethics? When do I need to contact another website to request permission to use the images from that site? Does anyone really care about that anymore. Where can I read about this?

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• Making Modular, Reusable and Loosely Coupled MVC Components

  - by Dusan

  I am building MVC3 application and need some general guidelines on how to manage complex client side interaction between my components. Here is my definition of one component in general way: Component which has it's own controller, model and view. All of the component's logic is placed inside these three parts and component is sort of "standalone", it contains it's own form, data needed for interaction, updates itself with Ajax and so on. Beside this internal logic and behavior of the component, it needs to be able to "Talk" to the outside world. By this I mean it should provide data and events (sort of) so when this component gets embedded in pages can notify other components which then can update based on the current state and data. I have an idea to use client ViewModel (in java-script) which would hookup all relevant components on page and control interaction between them. This would make components reusable, modular - independent of the context in which they are used. How would you do this, I am a bit stuck as I do not know if this is a good approach and there is a technical possibility to achieve this using java-script/jquery. The confusing part is about update via Ajax, how to ensure that component is properly linked to ViewModel when component is Ajax updated (or even worse removed or dynamically added). Also, how should this ViewModel be constructed and which technicalities to use here and in components to work as synergy??? On the web, I have found the various examples of the similar approach, but they are oversimplified (even for dummies) or over specific and do not provide valuable resource or general solution for this kind of implementation. If you have some serious examples it would be, also, very helpful. Note: My aim is to make interactions between many components on the same page simpler and more robust and elegant.

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• Linking Libraries in iOS?

  - by Bob Dole

  This is probably a totally noob question but I have missing links in my mind when thinking about linking libraries in iOS. I usually just add a new library that's been cross compiled and set the build and linker paths without really know what I'm doing. I'm hoping someone can help me fill in some gaps. Let's take the OpenCV library for instance. I have this totally working btw because of a really well written tutorial( http://niw.at/articles/2009/03/14/using-opencv-on-iphone/en ), but I'm just wanting to know what is exactly going on. What I'm thinking is happening is that when I build OpenCV for iOS is that your creating object code that gets placed in the .a files. This object code is just the implementation files( .m ) compiled. One reason you would want to do this is to make it hard to see the source code and so that you don't have to compile that source code every time. The .h files won't be put in the library ( .a ). You include the .h in your source files and these header files communicate with the object code library ( .a ) in some way. You also have to include the header files for your library in the Build Path and the Library itself in the Linker Path. So, is the way I view linking libraries correct? If , not can someone correct me on this ?

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• Ninject/DI: How to correctly pass initialisation data to injected type at runtime

  - by MrLane

  I have the following two classes: public class StoreService : IStoreService { private IEmailService _emailService; public StoreService(IEmailService emailService) { _emailService = emailService; } } public class EmailService : IEmailService { } Using Ninject I can set up bindings no problem to get it to inject a concrete implementation of IEmailService into the StoreService constructor. StoreService is actually injected into the code behind of an ASP.NET WebForm as so: [Ninject.Inject] public IStoreService StoreService { get; set; } But now I need to change EmailService to accept an object that contains SMTP related settings (that are pulled from the ApplicationSettings of the Web.config). So I changed EmailService to now look like this: public class EmailService : IEmailService { private SMTPSettings _smtpSettings; public void SetSMTPSettings(SMTPSettings smtpSettings) { _smtpSettings = smtpSettings; } } Setting SMTPSettings in this way also requires it to be passed into StoreService (via another public method). This has to be done in the Page_Load method in the WebForms code behind (I only have access to the Settings class in the UI layer). With manual/poor mans DI I could pass SMTPSettings directly into the constructor of EmailService and then inject EmailService into the StoreService constructor. With Ninject I don't have access to the instances of injected types outside of the objects they are injected to, so I have to set their data AFTER Ninject has already injected them via a separate public setter method. This to me seems wrong. How should I really be solving this scenario?

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• Price Drop for Processor based License on Exalytics

  - by Mike.Hallett(at)Oracle-BI&EPM

  ·       33% reduction in the list `per processor` license pricing for the Oracle BI Foundation Suite ·       New capacity-based licensing which allows customers to think big & start small, significantly lowering the entry price point for an Exalytics. Oracle BI Software List Price changes In response to new powerful platforms like the in-memory Oracle Exalytics with 40 cpu cores (counted under Oracle pricing policy as 20 “processors”), the list price of “Oracle BI Foundation Suite” (BIFS) is reduced by 33% from $450K per processor to $300K per processor. Capacity-based licensing on Exalytics (Trusted Partitions) “Capacity-based pricing” for the BIFS, Endeca, Essbase and Times Ten for Exalytics software is now available for Exalytics systems. This is delivered using “Oracle VM” (OVM).  We still ship a full Exalytics machine to all customers, but they may choose to only use and license a subset of the processors installed in the machine.   Customers can license Exalytics software in units of 5 “processors”: 5, 10, 15 or the full capacity 20.   As the customer’s implementation and workload increases, it is a simple matter to license additional processors and, using OVM, make them available to the BI or EPM application. Endeca Information Discovery now available on Exalytics Oracle has also announced the certification of “Oracle Endeca Information Discovery” (EID) on the Exalytics machine.    EID can be licensed alone or in combination with the BIFS & Times Ten for an Exalytics stack, and also participates in the capacity based pricing outlined above.   The Exalytics hardware is the perfect platform for EID, and provides superb power and performance for this in-memory hybrid text-search-analytics.   For more information : Oracle Price lists Oracle Partitioning Policy Discussion by Mark Rittman (Rittman Mead Consulting ltd.) on Oracle Trusted Partitions for Oracle Engineered Systems, Oracle Exalytics and Updated BI Foundation Pricing.

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• Can JSON be made easily and safely editable by the non-technical Excel crowd?

  - by glitch

  I'm looking for a data storage format that's very intuitive and easy to edit. It should be ideally targeted towards the same crowd as Excel. At the same time I would like the data structure to be a tree. Ideally this would be JSON, since it offers both the tree aspect and allows for more interesting constructs like arrays. That and parsing libraries for JSON are ubiquitous, so I don't have to reinvent the wheel. The problem is that, at least with a non-specialized text editor, JSON is a giant pain to edit for a non-technical user. I'm thinking along the lines of someone who might have used Excel in the past, but never a real text editor. Someone who might not be comfortable with the idea of preserving JSON syntax by hand. Are there data formats out there that would fit this profile? I'd very much prefer this to be a JSON actually, but then it would require a solid editing tool that would hide the underlying implementation from the user. Think Excel and how it abstracts CSV syntax from the user. The reason I'm looking for something like this is because the team has been working with pretty hierarchical data for a while now and we've hit the limits of how easy it is to represent in simple CSVs without having to create complex rules for how represent hierarchy semantics from each row. Any suggestions?

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• In MVC, why can't a model create a view?

  - by MUY Belgium

  I have a web application written in Perl with a controller, some "views" and some "Models". Each "Model" is corresponding to one "View". The controller (one file) creates an Model object corresponding to each view (view is a CGI argument) then retrieve the view from the module it has just created. Indeed, this should be bad thing but can you argue a bit more about it. My first idea was that since the object "Model" depends upon the "view", then the "model" is actually a view. But also the fact that ALL the cgi parameters are passed to the Model causes the "Model" to become not truelly a view but to loose all interest, since it is only related to the current implementation of the web apps. On other words, that the "Model" keep model but loose its "comprehensiveness" ("Model" is not easily understandable). I'm am quite new in project analysis, so please do not be too harsh. Why is this bad? I have made a prototype with the main structures I have understood of this web application, made as short as possible. #Model.pm package Model; import { # this requires an attribute called "view" # and this require an argument which is the cgi params } ... #View1.pm package View1; ... #Model1.pm package ModelView1 ; base Model; use View1; sub new { my $class = shift; my $arg = shift; Model::DoSomething($arg); $self->view = new View1($arg); ... } #controller.cgi my $model = 0; ... $model = new Model1( cgi_param => params() ); #there is severall models here ... print $model->get_view()->get_html();

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• Floating point undesireable in highly critical code?

  - by Kirt Undercoffer

  Question 11 in the Software Quality section of "IEEE Computer Society Real-World Software Engineering Problems", Naveda, Seidman, lists fp computation as undesirable because "the accuracy of the computations cannot be guaranteed". This is in the context of computing acceleration for an emergency braking system for a high speed train. This thinking seems to be invoking possible errors in small differences between measurements of a moving object but small differences at slow speeds aren't a problem (or shouldn't be), small differences between two measurements at high speed are irrelevant - can there be a problem with small roundoff errors during deceleration for an emergency braking system? This problem has been observed with airplane braking systems resulting in hydroplaning but could this actually happen in the context of a high speed train? The concern about fp errors seems to not be well-founded in this context. Any insight? The fp is used for acceleration so perhaps the concern is inching over a speed limit? But fp should be just fine if they use a double in whatever implementation language. The actual problem in the text states: During the inspection of the code for the emergency braking system of a new high speed train (a highly critical, real-time application), the review team identifies several characteristics of the code. Which of these characteristics are generally viewed as undesirable? The code contains three recursive functions (well that one is obvious). The computation of acceleration uses floating point arithmetic. All other computations use integer arithmetic. The code contains one linked list that uses dynamic memory allocation (second obvious problem). All inputs are checked to determine that they are within expected bounds before they are used.

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• How to code Time Stop or Bullet Time in a game?

  - by David Miler

  I am developing a single-player RPG platformer in XNA 4.0. I would like to add an ability that would make the time "stop" or slow down, and have only the player character move at the original speed(similar to the Time Stop spell from the Baldur's Gate series). I am not looking for an exact implementation, rather some general ideas and design-patterns. EDIT: Thanks all for the great input. I have come up with the following solution public void Update(GameTime gameTime) { GameTime newGameTime = new GameTime(gameTime.TotalGameTime, new TimeSpan(gameTime.ElapsedGameTime.Ticks / DESIRED_TIME_MODIFIER)); gameTime = newGameTime; or something along these lines. This way I can set a different time for the player component and different for the rest. It certainly is not universal enough to work for a game where warping time like this would be a central element, but I hope it should work for this case. I kinda dislike the fact that it litters the main Update loop, but it certainly is the easiest way to implement it. I guess that is essentialy the same as tesselode suggested, so I'm going to give him the green tick :)

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• Should you create a class within a method?

  - by Amndeep7

  I have made a program using Java that is an implementation of this project: http://nifty.stanford.edu/2009/stone-random-art/sml/index.html. Essentially, you create a mathematical expression and, using the pixel coordinate as input, make a picture. After I initially implemented this in serial, I then implemented it in parallel due to the fact that if the picture size is too large or if the mathematical expression is too complex (especially considering the fact that I made the expression recursively), it takes a really long time. During this process, I realized that I needed two classes which implemented the Runnable interface as I had to put in parameters for the run method, which you aren't allowed to do directly. One of these classes ended up being a medium sized static inner class (not large enough to make an independent class file for it though). The other though, just needed a few parameters to determine some indexes and the size of the for loop that I was making run in parallel - here it is: class DataConversionRunnable implements Runnable { int jj, kk, w; DataConversionRunnable(int column, int matrix, int wid) { jj = column; kk = matrix; w = wid; } public void run() { for(int i = 0; i < w; i++) colorvals[kk][jj][i] = (int) ((raw[kk][jj][i] + 1.0) * 255 / 2.0); increaseCounter(); } } My question is should I make it a static inner class or can I just create it in a method? What is the general programming convention followed in this case?

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• BPM Solution Catalogue–promote your process templates

  - by JuergenKress

  Oracle’s BPM Solution Catalogue showcasing our solutions with partners is now live. Take a look at the initial entries here. We are planning to use this catalogue not only to publish and highlight successful BPM implementations but also will be running campaigns in industry verticals with your solutions. If you have delivered a successful implementation in BPM and think it could be reused and applied again in a similar scenario in the same industry or in a similar environment, then we are keen to know about it and will add it to the solution catalogue. The solution catalogue will showcase successful BPM solutions both inside and outside Oracle. Be in touch with us on this via this e-mail id and we will make sure to add your solution. For more information you can also read the article “Leading-Edge BPM Benefits Without Bleeding-Edge Pain” SOA & BPM Partner Community For regular information on Oracle SOA Suite become a member in the SOA & BPM Partner Community for registration please visit  www.oracle.com/goto/emea/soa (OPN account required) If you need support with your account please contact the Oracle Partner Business Center. Blog Twitter LinkedIn Mix Forum Technorati Tags: BPM,Solution Catalogue,process templates,BPM Suite,SOA Community,Oracle SOA,Oracle BPM,Community,OPN,Jürgen Kress

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• The most mind-bending programming language? [closed]

  - by Xepoch

  From a reasonably common programming language, which do you find to be the most mind-bending? I have been listening to a lot of programming podcasts and taking some time to learn some new languages that are being considered upcoming, and important. I'm not necessarily talking about BrainFuck, but which language would you consider to be one that challenges the common programming paradigms? For me, I did some functional and logic (ex. Prolog) programming in the 90s, so can't say that I find anything special there. I am far from being an expert in it, but even today the most mind-bending programming language for me is Perl. Not because "Hello World" is hard to implement but rather there is so much lexical flexibility that some of the hardest solutions can be decomposed so poetically that I have to walk outside away from my terminal to clear my head. I'm not saying I'd likely sell a commercial software implementation, just that there is a distinct reason Perl is so (in)famous. Just look at the basic list of books on it. So, what is your mind-bending language that promotes your better programming and practices?

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• Is an event loop just a for/while loop with optimized polling?

  - by Alan

  I'm trying to understand what an event loop is. Often the explanation is that in the event loop, you do something until you're notified that an event occurred. You than handle the event and continue doing what you did before. To map the above definition with an example. I have a server which 'listens' in a event loop, and when a socket connection is detected, the data from it gets read and displayed, after which the server goes to the listening it did before. However, this event happening and us getting notified 'just like that' are to much for me to handle. You can say: "It's not 'just like that' you have to register an event listener". But what's an event listener but a function which for some reason isn't returning. Is it in it's own loop, waiting to be notified when an event happens? Should the event listener also register an event listener? Where does it end? Events are a nice abstraction to work with, however just an abstraction. I believe that in the end, polling is unavoidable. Perhaps we are not doing it in our code, but the lower levels (the programming language implementation or the OS) are doing it for us. It basically comes down to the following pseudo code which is running somewhere low enough so it doesn't result in busy waiting: while(True): do stuff check if event has happened (poll) do other stuff This is my understanding of the whole idea, and i would like to hear if this is correct. I am open in accepting that the whole idea is fundamentally wrong, in which case I would like the correct explanation. Best regards

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• Is there such thing as a "theory of system integration"?

  - by Jeff

  There is a plethora of different programs, servers, and in general technologies in use in organizations today. We, programmers, have lots of different tools at our disposal to help solve various different data, and communication challenges in an organization. Does anyone know if anyone has done an serious thinking about how systems are integrated? Let me give an example: Hypothetically, let's say I own a company that makes specialized suits a'la Iron Man. In the area of production, I have CAD tools, machining tools, payroll, project management, and asset management tools to name a few. I also have nice design space, where designers show off their designs on big displays, some touch, some traditional. Oh, and I also have one of these new fangled LEED Platinum buildings and it has number of different computer controlled systems, like smart window shutters that close when people are in the room, a HVAC system that adjusts depending on the number of people in the building, etc. What I want to know is if anyone has done any scientific work on trying to figure out how to hook all these pieces together, so that say my access control system is hooked to my payroll system, and my phone system allowing my never to swipe a time card, and to have my phone follow me throughout the building. This problem is also more than a technology challenge. Every technology implementation enables certain human behaviours, so the human must also be considered as a part of the system. Has anyone done any work in how effectively weave these components together? FYI: I am not trying to build a system. I want to know if anyone has thoroughly studied the process of doing a large integration project, how they develop their requirements, how they studied the human behaviors, etc.

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• Using runtime generic type reflection to build a smarter DAO

  - by kerry

  Have you ever wished you could get the runtime type of your generic class? I wonder why they didn’t put this in the language. It is possible, however, with reflection: Consider a data access object (DAO) (note: I had to use brackets b/c the arrows were messing with wordpress): public interface Identifiable { public Long getId(); } public interface Dao { public T findById(Long id); public void save(T obj); public void delete(T obj); } Using reflection, we can create a DAO implementation base class, HibernateDao, that will work for any object: import java.lang.reflect.Field; import java.lang.reflect.ParameterizedType; public class HibernateDao implements Dao { private final Class clazz; public HibernateDao(Session session) { // the magic ParameterizedType parameterizedType = (ParameterizedType) clazz.getGenericSuperclass(); return (Class) parameterizedType.getActualTypeArguments()[0]; } public T findById(Long id) { return session.get(clazz, id); } public void save(T obj) { session.saveOrUpdate(obj); } public void delete(T obj) { session.delete(obj); } } Then, all we have to do is extend from the class: public class BookDaoHibernateImpl extends HibernateDao { }

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• "Oracle Coherence 3.5" Book - My Humble Review

  - by [email protected]

    After reviewing the book in more detail I say again that it is a great guide for sure. Lots of important concepts that sometimes can be somewhat confusing are deeply reviewed, including all types of caching schemes and backing maps, and the cache topologies with their corresponding performances and very useful "When to use it?" sections. Some functionalities that are very desirable or used a lot are reviewed with examples and best practices of implementation, including: Data affinity Querying Pagination Indexes Aggregations Event processing, listening and triggering Data persistence Security Regarding the networking and architecture topics, Coherence*Extend is exhaustively reviewed, including C++ and .NET clients, with very good tips and examples, even including source codes. Personally, I am also glad to see that the address providers (<address-provider> tag), new feature in Coherence 3.5 which is a way to programmatically provide well-known addresses in order to connect to the cluster, is mentioned on the book, because it provides new functionalities to satisfy some special configuration requirements for example: Provide a way to switch extend nodes in cases of failure Implement custom load balancing algorithms and/or dynamic discovery of TCP/IP connection acceptors Dynamically assign TCP address and port settings when binding to a server socket Another very interesting and useful section is the "Coherent Bank Sample Application", which is a great tutorial, useful to understand how Coherence interacts with third party products establishing a clear integration with them, including the use of non-Oracle products like MS Visual Studio.  

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• Architecture of an action multiplayer game from scratch

  - by lcf

  Not sure whether it's a good place to ask (do point me to a better one if it's not), but since what we're developing is a game - here it goes. So this is a "real-time" action multiplayer game. I have familiarized myself with concepts like lag compensation, view interpolation, input prediction and pretty much everything that I need for this. I have also prepared a set of prototypes to confirm that I understood everything correctly. My question is about the situation when game engine must be rewind to the past to find out whether there was a "hit" (sometimes it may involve the whole 'recomputation' of the world from that moment in the past up to the present moment. I already have a piece of code that does it, but it's not as neat as I need it to be. The domain logic of the app (the physics of the game) must be separated from the presentation (render) and infrastructure tools (e.g. the remote server interaction specifics). How do I organize all this? :) Is there any worthy implementation with open sources I can take a look at? What I'm thinking is something like this: -> Render / User Input -> Game Engine (this is the so called service layer) -> Processing User Commands & Remote Server -> Domain (Physics) How would you add into this scheme the concept of "ticks" or "interactions" with the possibility to rewind and recalculate "the game"? Remember, I cannot change the Domain/Physics but only the Game Engine. Should I store an array of "World's States"? Should they be just some representations of the world, optimized for this purpose somehow (how?) or should they be actual instances of the world (i.e. including behavior and all that). Has anybody had similar experience? (never worked on a game before if that matters)

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