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  • generating maps

    - by gardian06
    This is a conglomeration question when answering please specify which part you are addressing. I am looking at creating a maze type game that utilizes elevation. I have a few features I would like to have, but am unsure as to some of the implementation. I have done work doing fileIO maze generation (using a key to read the file, and then generate the level based on that file), but I am unsure how to think about this with elevation in the mix. I think height maps might be a good approach, but don't know how to represent them effectively. for a height map which is more beneficial XML(containing h[u,v] data and key definition), CSV (item1 is key reference, item2 is elevation), or another approach that I have not thought of yet? When it comes to placing the elevation values themselves what kind of deltah values are appropriate to have it noticeable at about a 60degree angle while not really effecting gravity driven physics (assuming some effect while moving up/down hill)? I am thinking of maybe going to procedural generation at some point, but am wondering if it is practical to have a procedurally generated grid (wall squares possibly same dimensions as the open space squares), or if designing to a thin wall open spaces is better? this decision will effect the amount of work need on the graphics end for uniform vs. irregular walls. EDIT: game will be a elevation maze shooter. levels/maps will be mazes with elevation the player has to negotiate. elevations will have effects on "combat" vision, and movement

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  • 3D physics engine for accurate collision handling on desktop/laptop computers (non-console)

    - by Georges Oates Larsen
    What are your suggestions for a physics engine that satisfies the following criteria? Capable of calculating collisions between multiple concave mesh-based colliders Handles many collisions going on at once (for instance one mesh being wedged between two others, which themselves may be wedged between two meshes) Does not allow for collider passthrough, even at high speeds. For instance, if I am applying force to a programmatically hinged object that makes it spin, I do not want it to pass through another rigidbody that it collides with while spinning. I have this problem using PhysX As implied before, reacts well to hinged objects, preferably has its own implementation of a hinge, but I am willing to program my own. The important part is that it has some sort of interface that guarantees accurate collision tracking even when dealing with these things Platform independent -- runs on mac as well as PC, also not tied down to specific graphics cards I think that's the best way to explain what I am looking for. Basically, I need SUPER reliable collisions. Something that can't be accomplished with a simple ray casting approach that sends a ray from the last position of the object to the current position (as this object may be potentially large and colliding with small objects via rotation) Bonus points for also including an OPEN SOURCE engine.

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  • Partner Webcast - Oracle Business Process Management: What’s new in Oracle BPM 11.1.1.7.0 - 04 July 2013

    - by Thanos
    Business processes are at the heart of what makes or breaks a business—and what differentiates it from the competition. Business processes that deliver operational efficiency, business visibility, excellent customer experience, and agility give the enterprise an edge over the competition. Business managers need process management tools that enable them to make impactful changes. Oracle has been always a leader in this area and the new version of Oracle BPM 11g takes that even further by providing complete web based process modeling, simulation and implementation including designing the user interface and business logic. That provides business users with ability to take complete control over the business processes without sacrificing the vast service integration capabilities delivered traditionally by IT using SOA approach. Oracle Business Process Management is the industry's most complete and business user-friendly BPM solution. Register today for this webcast and find out more on the latest and most exciting new features which are now available in Oracle BPM Suite. Agenda Introduction do Oracle BPM 11g Exciting new features in this release Revamped Process Composer Simulations Web Forms Process Player Adaptive Case Management Instance Revisioning Other features Demonstration Q&A Delivery Format This FREE online LIVE eSeminar will be delivered over the Web. Registrations received less than 24hours prior to start time may not receive confirmation to attend. Duration: 1 hour Register Now! For any questions please contact us at [email protected] Visit our ISV Migration Center blog & Facebook Page or Follow us @oracleimc  to learn more on Oracle Technologies, upcoming partner webcasts and events. Existing content available YouTube - SlideShare - Oracle Mix

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  • Static DataTable or DataSet in a class - bad idea?

    - by Superbest
    I have several instances of a class. Each instance stores data in a common database. So, I thought "I'll make the DataTable table field static, that way every instance can just add/modify rows to its own table field, but all the data will actually be in one place!" However, apparently it's a bad idea to do use static fields, especially if it's databases: Don't Use "Static" in C#? Is this a bad idea? Will I run into problems later on if I use it? This is a small project so I can accept no testing as a compromise if that is the only drawback. The benefit of using a static database is that there can be many objects of type MyClass, but only one table they all talk to, so a static field seems to be an implementation of exactly this, while keeping syntax concise. I don't see why I shouldn't use a static field (although I wouldn't really know) but if I had to, the best alternative I can think of is creating one DataTable, and passing a reference to it when creating each instance of MyClass, perhaps as a constructor parameter. But is this really an improvement? It seems less intuitive than a static field.

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  • Game Messaging System Design

    - by you786
    I'm making a simple game, and have decided to try to implement a messaging system. The system basically looks like this: Entity generates message - message is posted to global message queue - messageManager notifies every object of the new message through onMessageReceived(Message msg) - if object wants, it acts on the message. The way I'm making message objects is like this: //base message class, never actually instantiated abstract class Message{ Entity sender; } PlayerDiedMessage extends Message{ int livesLeft; } Now my SoundManagerEntity can do something like this in its onMessageReceived() method public void messageReceived(Message msg){ if(msg instanceof PlayerDiedMessage){ PlayerDiedMessage diedMessage = (PlayerDiedMessage) msg; if(diedMessage.livesLeft == 0) playSound(SOUND_DEATH); } } The pros to this approach: Very simple and easy to implement The message can contain as much as information as you want, because you can just create a new Message subclass that has whatever info necessary. The cons: I can't figure out how I can recycle Message objects to a object pool, unless I have a different pool for each subclass of Message. So I have lots and lots of object creation/memory allocation over time. Can't send a message to a specific recipient, but I haven't needed that yet in my game so I don't mind it too much. What am I missing here? There must be a better implementation or some idea that I'm missing.

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  • What technical details should a programmer of a web application consider before making the site public?

    - by Joel Coehoorn
    What things should a programmer implementing the technical details of a web application consider before making the site public? If Jeff Atwood can forget about HttpOnly cookies, sitemaps, and cross-site request forgeries all in the same site, what important thing could I be forgetting as well? I'm thinking about this from a web developer's perspective, such that someone else is creating the actual design and content for the site. So while usability and content may be more important than the platform, you the programmer have little say in that. What you do need to worry about is that your implementation of the platform is stable, performs well, is secure, and meets any other business goals (like not cost too much, take too long to build, and rank as well with Google as the content supports). Think of this from the perspective of a developer who's done some work for intranet-type applications in a fairly trusted environment, and is about to have his first shot and putting out a potentially popular site for the entire big bad world wide web. Also, I'm looking for something more specific than just a vague "web standards" response. I mean, HTML, JavaScript, and CSS over HTTP are pretty much a given, especially when I've already specified that you're a professional web developer. So going beyond that, Which standards? In what circumstances, and why? Provide a link to the standard's specification.

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  • TXPAUSE : polite waiting for hardware transactional memory

    - by Dave
    Classic locks are an appropriate tool to prevent potentially conflicting operations A and B, invoked by different threads, from running at the same time. In a sense the locks cause either A to run before B or vice-versa. Similarly, we can replace the locks with hardware transactional memory, or use transactional lock elision to leverage potential disjoint access parallelism between A and B. But often we want A to wait until B has run. In a Pthreads environment we'd usually use locks in conjunction with condition variables to implement our "wait until" constraint. MONITOR-MWAIT is another way to wait for a memory location to change, but it only allows us to track one cache line and it's only available on x86. There's no similar "wait until" construct for hardware transactions. At the instruction-set level a simple way to express "wait until" in transactions would be to add a new TXPAUSE instruction that could be used within an active hardware transaction. TXPAUSE would politely stall the invoking thread, possibly surrendering or yielding compute resources, while at the same time continuing to track the transaction's address-set. Once a transaction has executed TXPAUSE it can only abort. Ideally that'd happen when some other thread modifies a variable that's in the transaction's read-set or write-set. And since we're aborting all writes would be discarded. In a sense this gives us multi-location MWAIT but with much more flexibility. We could also augment the TXPAUSE with a cycle-count bound to cap the time spent stalled. I should note that we can already enter a tight spin loop in a transaction to wait for updates to address-set to cause an abort. Assuming that the implementation monitors the address-set via cache-coherence probes, by waiting in this fashion we actually communicate via the probes, and not via memory values. That is the updating thread signals the waiter via probes instead of by traditional memory values. But TXPAUSE gives us a polite way to spin.

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  • The Power of Specialization – google ads for SOA & BPM Specialized Partners

    - by JuergenKress
    For SOA & BPM specialized partner we offer free google advertisement to promote your Oracle SOA & BPM service offerings on your website or your SOA & BPM events. We will host the complete campaign management. To create your google campaign please send us below: Your campaign text: 3 lines of text each 35 letters (NOT more letters!) Your campaign link: direct link to the website you want to promote Ideas for the website which we will promote with the google ads: Your Oracle SOA Service offerings with concrete offering e.g. SOA Discovery Workshop Oracle SOA Specialized Logo Your Oracle SOA References Your SOA Implementation consultant with pictures Your SOA sales contact persons Example of an SOA Specialization text ad: Oracle SOA Specialized plan to become more agile? eProseed the Oracle SOA Experts An interview with Griffiths Waite's Business Development Director highlighting the benefits of the Oracle Specialization Programme. 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: Specializaion,Benefits Specialization,marketing,SOA Community,Oracle SOA,Oracle BPM,Community,OPN,Jürgen Kress

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  • Will proprietary software-based sound enhancements work with Ubuntu? (BeatsAudio, Dolby)

    - by LiveWireBT
    This question is targeted at mainstream or gamer-grade software-based audio/sound enhancements, found in highly integrated computing and entertainment systems like laptops, tablets and smartphones. These are mostly marketed with fancy badges of known audio-releated brands on the product or packaging, while being mostly uncertain about the actual implementation or components used and poorly differentiated from the general audio capabilities of the system or device. This question is not about actual hardware like speakers. If your headphones are not properly detected, your speakers are assigned wrong, work partially or not at all then your soundcard or chip is not properly detected and you should take a look at troubleshooting audio issues. This question is also not about enthusiast or recording-grade hardware like recording interfaces, amplifiers and DACs in a variety of formfactors. And this question is also not about audio encoding and playback of different audio formats like Dolby Digital, Dolby TrueHD and DTS. Most of these may be subject to patents and licensing, see restricted formats. If you are just searching for an equalizer, please take a look at this question: Is there any Sound enhancers/equalizer? Simply speaking: Every feature where you would flip a switch or check a box in a fancy looking interface in Windows that makes the sound change from neutral to fancy.

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  • What level of detail to use in an interface members descriptions?

    - by famousgarkin
    I am extracting interfaces from some classes in .NET, and I am not completely sure about what level of detail of description to use for some of the interface members (properties, methods). An example: interface ISomeInterface { /// <summary> /// Checks if the object is checked out. /// </summary> /// <returns> /// Returns true if the object is checked out, or if the object locking is not enabled, /// otherwise returns false. /// </returns> bool IsObjectCheckedOut(); } class SomeImplementation : ISomeInterface { public bool IsObjectCheckedOut() { // An implementation of the method that returns true if the object is checked out, // or if the object locking is not enabled } } The part in question is the <returns>...</returns> section of the IsObjectCheckedOut description in the interface. Is it ok to include such a detail about return value in the interface itself, as the code that will work with the interface should know exactly what that method will do? All the current implementations of the method will do just that. But is it ok to limit the possible other/future implementations by description this way? Or should this not be included in the interface description, as there is no way to actually ensure that other/future implementations will do exactly this? Is it better to be as general as possible regarding the interface in such circumstances? I am currently inclined to the latter option.

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  • 'Buy the app' landing page implementations: redirect or javascript popup?

    - by benwad
    My site (using Django) has an app that I'm trying to push - I currently have a piece of middleware that redirects the user to a page advertising the app if they're accessing the page on the iPhone, then setting a cookie so that the user isn't bugged by the message every time they visit the site. This works fine, however checking the page with the mobile Googlebot checker shows that the Googlebot gets stuck in the redirect (since it doesn't store cookies) and therefore won't index the proper content. So, I'm trying to think of an alternative implementation that won't hurt the site's Google ranking and won't have any other adverse effects. I've considered a couple of options: Redirect (the current solution), but don't redirect if the user agent matches the Googlebot's UA string. This would be ideal, however I'm not sure if Google like their bot being treated differently from other users, and I'm afraid the site's ranking may be somehow penalised if I go ahead with this. Use a Javascript popup instead of a redirect. This would make sure the Googlebot finds the content it needs, however I envision this approach causing compatibility issues with the myriad mobile devices/browsers out there, and may affect the page load time. How valid are these options? And is there a better option for implementing this feature out there? I've tried researching this topic but surprisingly can't find any reputable-looking blog posts that explore this topic.

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  • What is the value of checking in failing unit tests?

    - by Adam W.
    While there are ways of keeping unit tests from being executed, what is the value of checking in failing unit tests? I will use a simple example: Case Sensitivity. The current code is case sensitive. A valid input into the method is "Cat" and it would return an enum of Animal.Cat. However, the desired functionality of the method should not be case sensitive. So if the method described was passed "cat" it could possibly return something like Animal.Null instead of Animal.Cat and the unit test would fail. Though a simple code change would make this work, a more complex issue may take weeks to fix, but identifying the bug with a unit test could be a less complex task. The application currently being analyzed has 4 years of code that "works". However, recent discussions regarding unit tests have found flaws in the code. Some just need explicit implementation documentation (ex. case sensitive or not), or code that does not execute the bug based on how it is currently called. But unit tests can be created executing specific scenarios that will cause the bug to be seen and are valid inputs. What is the value of checking in unit tests that exercise the bug until someone can get around to fixing the code? Should this unit test be flagged with ignore, priority, category etc, to determine whether a build was successful based on tests executed? Eventually the unit test should be created to execute the code once someone fixes it. On one hand it shows that identified bugs have not been fixed. On the other, there could be hundreds of failed unit tests showing up in the logs and weeding through the ones that should fail vs. failures due to a code check-in would be difficult to find.

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  • WCF REST Error Handler

    - by Elton Stoneman
    I’ve put up on GitHub a sample WCF error handler for REST services, which returns proper HTTP status codes in response to service errors.   The code is very simple – a ServiceBehavior implementation which can be specified in config to tag the RestErrorHandler to a service. Any uncaught exceptions will be routed to the error handler, which sets the HTTP status code and description in the response, based on the type of exception.   The sample defines a ClientException which can be thrown in code to indicate a problem with the client’s request, and the response will be a status 400 with a friendly error message:       throw new ClientException("Invalid userId. Must be provided as a positive integer");   - responds:   Request URL http://localhost/Sixeyed.WcfRestErrorHandler.Sample/ErrorProneService.svc/lastLogin?userId=xyz   Error Status Code: 400, Description: Invalid userId. Must be provided as a positive integer   Any other uncaught exceptions are hidden from the client. The full details are logged with a GUID to identify the error, and the response to the client is a status 500 with a generic message giving them the GUID to follow up on:       var iUserId = 0;     var dbz = 1 / iUserId;   - logs the divide-by-zero error and responds:   Request URL http://localhost/Sixeyed.WcfRestErrorHandler.Sample/ErrorProneService.svc/dbz     Error Status Code: 500, Description: Something has gone wrong. Please contact our support team with helpdesk ID: C9C5A968-4AEA-48C7-B90A-DEC986F80DA5   The sample demonstrates two techniques for building the response. For client exceptions, a friendly HTML response is sent in the body as well as the status code and description. Personally I prefer not to do that – it doesn’t make sense to get a 400 error and find text/html when you’re expecting application/json, but it’s easy to do if that’s the functionality you want. The other option is to send an empty response, which the sample does with server exceptions.   The obvious extension is to have multiple exceptions representing all the status codes you want to provide, then your code is as simple as throwing the relevant exception – UnauthorizedException, ForbiddenExeption, NotImplementedException etc – anywhere in the stack, and it will be handled nicely.

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  • How could I implement 3D player collision with rotation in LWJGL?

    - by Tinfoilboy
    I have a problem with my current collision implementation. Currently for player collision, I just use an AABB where I check if another AABB is in the way of the player, as shown in this code. (The code below is a sample of checking for collisions in the Z axis) for (int z = (int) (this.position.getZ()); z > this.position.getZ() - moveSpeed - boundingBoxDepth; z--) { // The maximum Z you can get. int maxZ = (int) (this.position.getZ() - moveSpeed - boundingBoxDepth) + 1; AxisAlignedBoundingBox aabb = WarmupWeekend.getInstance().currentLevel.getAxisAlignedBoundingBoxAt(new Vector3f(this.position.getX(), this.position.getY(), z)); AxisAlignedBoundingBox potentialCameraBB = new AxisAlignedBoundingBox(this, "collider", new Vector3f(this.position.getX(), this.position.getY(), z), boundingBoxWidth, boundingBoxHeight, boundingBoxDepth); if (aabb != null) { if (potentialCameraBB.colliding(aabb) && aabb.COLLIDER_TYPE.equalsIgnoreCase("collider")) { break; } else if (!potentialCameraBB.colliding(aabb) && z == maxZ) { if (this.grounded) { playFootstep(); } this.position.z -= moveSpeed; break; } } else if (z == maxZ) { if (this.grounded) { playFootstep(); } this.position.z -= moveSpeed; break; } } Now, when I tried to implement rotation to this method, everything broke. I'm wondering how I could implement rotation to this block (and as all other checks in each axis are the same) and others. Thanks in advance.

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  • How to choose a server side language / framework

    - by pllee
    I am trying to come up with a list / ranking system on determining which server language to choose for a particular website. Assume that familiarity with a certain language is not important and the implementation can be done in any language. Here are some things that might be important but I am not sure how to rank them : Maintainability. Libraries. For example, Memcached and NoSql support right out the box would be really nice addition to a particular framework. 3rd party SDK's. For example, if I need Paypal on my site they openly provide SDK's for all senarios in Java, PHP and .Net. If I choose Django I would have to rely on 3rd party libraries that are don't support everything and are not officially maintained. Would that be dealbreaker for Django? Performance This one is tricky to put on a generic list because it can be a deal breaker but for many websites performance will not be an issue that the language/framework is responsible for. Cost (hosting, open source). edit - Any reason for the votes to close? I didn't see any duplicates mentioned and the question should not drum up a flame war.

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  • BPI On Demand achieves both Oracle Fusion CRM Cloud Service 2013 Specialisation and Reseller status!

    - by Richard Lefebvre
    Oracle is delighted to share with you that BPI OnDemand has achieved the Oracle Fusion CRM Cloud Service 2013 Specialization and is the EMEA first ever Oracle Sales Cloud reseller ! One of Oracle's most active CRM SaaS partners across EMEA, BPI OnDemand operates out of the UK with subsidiaries in Spain and South Africa that will also benefit locally from the specialization and reseller status. Normal 0 false false false EN-US X-NONE X-NONE MicrosoftInternetExplorer4 /* 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-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0cm 5.4pt 0cm 5.4pt; mso-para-margin:0cm; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:10.0pt; font-family:"Times New Roman","serif";} BPI OnDemand distinguishes itself from other Oracle Sales Cloud integrators with 2 unique implementation options: 1) Rapid Advantage Fixed Scope for as low as £20,000 or their famous 2) Zero upfront cost Fully Managed Cloud CRM Service which has no equivalent in Europe. BPI OnDemand has already 2 Oracle Sales Cloud live customers and is engaging in many other opportunities including large corporate accounts. Meet BPI OnDemand here or on LinkedIn or on Twitter

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  • The idea of functionN in Scala / Functionaljava

    - by Luke Murphy
    From brain driven development It turns out, that every Function you’ll ever define in Scala, will become an instance of an Implementation which will feature a certain Function Trait. There is a whole bunch of that Function Traits, ranging from Function1 up to Function22. Since Functions are Objects in Scala and Scala is a statically typed language, it has to provide an appropriate type for every Function which comes with a different number of arguments. If you define a Function with two arguments, the compiler picks Function2 as the underlying type. Also, from Michael Froh's blog You need to make FunctionN classes for each number of parameters that you want? Yes, but you define the classes once and then you use them forever, or ideally they're already defined in a library (e.g. Functional Java defines classes F, F2, ..., F8, and the Scala standard library defines classes Function1, ..., Function22) So we have a list of function traits (Scala), and a list of interfaces (Functional-java) to enable us to have first class funtions. I am trying to understand exactly why this is the case. I know, in Java for example, when I write a method say, public int add(int a, int b){ return a + b; } That I cannot go ahead and write add(3,4,5); ( error would be something like : method add cannot be applied to give types ) We simply have to define an interface/trait for functions with different parameters, because of static typing?

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  • best way to send messages to all subscribers with multiple subscriptions and multiple providers

    - by coding_idiot
    I'm writing an application in which - Many users can subsribe to posts made by another users. So for a single publisher there can be many subscribers. When a message is posted by an user X, all users who have subscribed to messages of User X will be sent an email. How to achieve this ? I'm thinking of using publish-subscribe pattern. And then I came through JMS. Which is the best JMS implementation to use according to your experience ? Or else what else solution do you propose to the given problem ? Shall I go for a straight-forward solution ?: User x posts a message, I find all users (from database) who subscribe to user x and then for every user, I call the sendEmail() method. [EDIT] My intention here is not to send-emails. I'm really sorry if it wasn't clear. I also have to send kind of system-notifications apart from Email to all subscribers. Right now, I've implemented the email-sending as a threadPool

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  • How do I drag my widgets without dragging other widgets?

    - by Cypher
    I have a bunch of drag-able widgets on screen. When I am dragging one of the widgets around, if I drag the mouse over another widget, that widget then gets "snagged" and is also dragged around. While this is kind of a neat thing and I can think of a few game ideas based on that alone, that was not intended. :-P Background Info I have a Widget class that is the basis for my user interface controls. It has a bunch of properties that define it's size, position, image information, etc. It also defines some events, OnMouseOver, OnMouseOut, OnMouseClick, etc. All of the event handler functions are virtual, so that child objects can override them and make use of their implementation without duplicating code. Widgets are not aware of each other. They cannot tell each other, "Hey, I'm dragging so bugger off!" Source Code Here's where the widget gets updated (every frame): public virtual void Update( MouseComponent mouse, KeyboardComponent keyboard ) { // update position if the widget is being dragged if ( this.IsDragging ) { this.Left -= (int)( mouse.LastPosition.X - mouse.Position.X ); this.Top -= (int)( mouse.LastPosition.Y - mouse.Position.Y ); } ... // define and throw other events if ( !this.WasMouseOver && this.IsMouseOver && mouse.IsButtonDown( MouseButton.Left ) ) { this.IsMouseDown = true; this.MouseDown( mouse, new EventArgs() ); } ... // define and throw other events } And here's the OnMouseDown event where the IsDraggable property gets set: public virtual void OnMouseDown( object sender, EventArgs args ) { if ( this.IsDraggable ) { this.IsDragging = true; } } Problem Looking at the source code, it's obvious why this is happening. The OnMouseDown event gets fired whenever the mouse is hovered over the Widget and when the left mouse button is "down" (but not necessarily in that order!). That means that even if I hold the mouse down somewhere else on screen, and simply move it over anything that IsDraggable, it will "hook" onto the mouse and go for a ride. So, now that it's obvious that I'm Doing It Wrong™, how do I do this correctly?

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  • Floating point undesirable 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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  • OSB, Service Callouts and OQL

    - by Sabha
    Oracle Fusion Middleware customers use Oracle Service Bus (OSB) for virtualizing Service endpoints and implementing stateless service orchestrations. Behind the performance and speed of OSB, there are a couple of key design implementations that can affect application performance and behavior under heavy load. One of the heavily used feature in OSB is the Service Callout pipeline action for message enrichment and invoking multiple services as part of one single orchestration. Overuse of this feature, without understanding its internal implementation, can lead to serious problems. This series will delve into OSB internals, the problem associated with usage of Service Callout under high loads, diagnosing it via thread dump and heap dump analysis using tools like ThreadLogic and OQL (Object Query Language) and resolving it. The first section in the series will mainly cover the threading model used internally by OSB for implementing Route Vs. Service Callouts. The second section of the "OSB, Service Callouts and OQL" blog posting will delve into thread dump analysis of OSB server and detecting threading issues relating to Service Callout and using Heap Dump and OQL to identify the related Proxies and Business services involved. The final section of the series will focus on the corrective action to avoid Service Callout related OSB serer hangs. Before we dive into the solution, we need to briefly discus about Work Managers in WLS. Please refer to the blog posting for more details.

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  • Endeca Information Discovery 3-Day Hands-on Training Boot-Camp

    - by Mike.Hallett(at)Oracle-BI&EPM
    For Oracle Partners, on October 15-17, 2012 in Paris, France: Register here. The Oracle Endeca Information Discovery (OEID) Boot-Camp is designed to give partners an understanding of OEID’s features, and how it complements the existing Oracle Business Intelligence suite. Participants will learn how to develop & implement solutions using a Data Discovery method.  Training is in English. What will be covered? The Oracle Endeca Information Discovery (OEID) Boot Camp is a three-day class with a combination of lecture and hands-on exercises, tailored to make participants aware of the Oracle Endeca Information Discovery platform, and to gain valuable skills for the implementation of projects.   Prerequisites You must bring a laptop with you for the Hands-on labs: Attendees should have experience and familiarity with the basic concepts of business intelligence and be OPN Partners with Gold or above membership.  This training is free to OPN Partners. Click here for more information. Where and When ? Monday, October 15th until Wednesday, October 17th included  9:00 - 18:00 Oracle France 15, boulevard Charles de Gaulle 92715 Colombes: Access Venue Map Register here  : NOTE there is a Limited number of seats, you will get confirmation within 2 weeks.

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  • Dealing with Fine-Grained Cache Entries in Coherence

    - by jpurdy
    On occasion we have seen significant memory overhead when using very small cache entries. Consider the case where there is a small key (say a synthetic key stored in a long) and a small value (perhaps a number or short string). With most backing maps, each cache entry will require an instance of Map.Entry, and in the case of a LocalCache backing map (used for expiry and eviction), there is additional metadata stored (such as last access time). Given the size of this data (usually a few dozen bytes) and the granularity of Java memory allocation (often a minimum of 32 bytes per object, depending on the specific JVM implementation), it is easily possible to end up with the case where the cache entry appears to be a couple dozen bytes but ends up occupying several hundred bytes of actual heap, resulting in anywhere from a 5x to 10x increase in stated memory requirements. In most cases, this increase applies to only a few small NamedCaches, and is inconsequential -- but in some cases it might apply to one or more very large NamedCaches, in which case it may dominate memory sizing calculations. Ultimately, the requirement is to avoid the per-entry overhead, which can be done either at the application level by grouping multiple logical entries into single cache entries, or at the backing map level, again by combining multiple entries into a smaller number of larger heap objects. At the application level, it may be possible to combine objects based on parent-child or sibling relationships (basically the same requirements that would apply to using partition affinity). If there is no natural relationship, it may still be possible to combine objects, effectively using a Coherence NamedCache as a "map of maps". This forces the application to first find a collection of objects (by performing a partial hash) and then to look within that collection for the desired object. This is most naturally implemented as a collection of entry processors to avoid pulling unnecessary data back to the client (and also to encapsulate that logic within a service layer). At the backing map level, the NIO storage option keeps keys on heap, and so has limited benefit for this situation. The Elastic Data features of Coherence naturally combine entries into larger heap objects, with the caveat that only data -- and not indexes -- can be stored in Elastic Data.

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  • How to handle sorting of complex objects?

    - by AedonEtLIRA
    How would one sort a list of objects that have more than one sortable element? Suppose you have a simple object Car and car is a defined as such: class Car { public String make; public String model; public int year; public String color; // ... No methods, just a structure / container } I designed a simple framework that would allow for multiple SortOptions to be provided to a Sorter that would then sort the list. interface ISorter<T> { List<T> sort(List<T> items); void addSortOption(ISortOption<T> option); ISortOption<T>[] getSortOptions(); void setSortOption(ISortOption<T> option); } interface ISortOption<T> { String getLabel(); int compare(T t1, T t2); } Example use class SimpleStringSorter extends MergeSorter<String> { { addSorter(new AlphaSorter()); } private static final class AlphaSorter implements ISortOption<String> { // ... implementation of alpha compare and get label } } The issue with this solution is that it is not easily expandable. If car was to ever receive a new field, say, currentOwner. I would need to add the field, then track down the sorter class file, implement a new sort option class then recompile the application for redistribution. Is there an easier more expandable/practical way to sort data like this?

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  • What's so great about Clojure?

    - by marco-fiset
    I've been taking a look at Clojure lately and I stumbled upon this post on Stackoverflow that indicates some projects following best practices, and overall good Clojure code. I wanted to get my head around the language after reading some basic tutorials so I took a look at some "real-world" projects. After looking at ClojureScript and Compojure (two the the aforementioned "good" projects), I just feel like Clojure is a joke. I don't understand why someone would pick Clojure over say, Ruby or Python, two languages that I love and have such a clean syntax and are very easy to pick up whereas Clojure uses so much parenthesis and symbols everywhere that it ruins the readability for me. I think that Ruby and Python are beautiful, readable and elegant. They are easy to read even for someone who does not know the language inside out. However, Clojure is opaque to me and I feel like I must know every tiny detail about the language implementation in order to be able to understand any code. So please, enlighten me! What is so good about Clojure? What is the absolute minimum that I should know about the language in order to appreciate it?

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