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  • Plan variable and call dependencies

    - by Gerenuk
    I'd like to write down the design of my program to understand the dependencies and calls better. I know there are class diagrams which show inheritance and attribute variables. However I'd also like to document the input parameters to method functions and in particular which calls the methods function executes inside (e.g. on the input parameters). Also sometimes it might be useful to show how actual objects are connected (if there is a standard structure). This way I can have a better understanding of the modules and design before starting to program. Can you suggest a method to do this software design? It should be one-to-one to programming code structure so that I really notice all quirks beforehand (instead of high-level design where thing are hard to implement without further work). Maybe some special diagram or tool or a combination? It is static dependency and call design rather than time dependent execution monitoring. (I use Python if you have any specialized recommendations).

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  • Why do I get an exception when playing multiple sound instances?

    - by Boreal
    Right now, I'm adding a rudimentary sound engine to my game. So far, I am able to load in a WAV file and play it once, then free up the memory when I close the game. However, the game crashes with a nice ArgumentOutOfBoundsException when I try to play another sound instance. Specified argument was out of the range of valid values. Parameter name: readLength I'm following this tutorial pretty much exactly, but I still keep getting the aforementioned error. Here's my sound-related code. /// <summary> /// Manages all sound instances. /// </summary> public static class Audio { static XAudio2 device; static MasteringVoice master; static List<SoundInstance> instances; /// <summary> /// The XAudio2 device. /// </summary> internal static XAudio2 Device { get { return device; } } /// <summary> /// Initializes the audio device and master track. /// </summary> internal static void Initialize() { device = new XAudio2(); master = new MasteringVoice(device); instances = new List<SoundInstance>(); } /// <summary> /// Releases all XA2 resources. /// </summary> internal static void Shutdown() { foreach(SoundInstance i in instances) i.Dispose(); master.Dispose(); device.Dispose(); } /// <summary> /// Registers a sound instance with the system. /// </summary> /// <param name="instance">Sound instance</param> internal static void AddInstance(SoundInstance instance) { instances.Add(instance); } /// <summary> /// Disposes any sound instance that has stopped playing. /// </summary> internal static void Update() { List<SoundInstance> temp = new List<SoundInstance>(instances); foreach(SoundInstance i in temp) if(!i.Playing) { i.Dispose(); instances.Remove(i); } } } /// <summary> /// Loads sounds from various files. /// </summary> internal class SoundLoader { /// <summary> /// Loads a .wav sound file. /// </summary> /// <param name="format">The decoded format will be sent here</param> /// <param name="buffer">The data will be sent here</param> /// <param name="soundName">The path to the WAV file</param> internal static void LoadWAV(out WaveFormat format, out AudioBuffer buffer, string soundName) { WaveStream wave = new WaveStream(soundName); format = wave.Format; buffer = new AudioBuffer(); buffer.AudioData = wave; buffer.AudioBytes = (int)wave.Length; buffer.Flags = BufferFlags.EndOfStream; } } /// <summary> /// Manages the data for a single sound. /// </summary> public class Sound : IAsset { WaveFormat format; AudioBuffer buffer; /// <summary> /// Loads a sound from a file. /// </summary> /// <param name="soundName">The path to the sound file</param> /// <returns>Whether the sound loaded successfully</returns> public bool Load(string soundName) { if(soundName.EndsWith(".wav")) SoundLoader.LoadWAV(out format, out buffer, soundName); else return false; return true; } /// <summary> /// Plays the sound. /// </summary> public void Play() { Audio.AddInstance(new SoundInstance(format, buffer)); } /// <summary> /// Unloads the sound from memory. /// </summary> public void Unload() { buffer.Dispose(); } } /// <summary> /// Manages a single sound instance. /// </summary> public class SoundInstance { SourceVoice source; bool playing; /// <summary> /// Whether the sound is currently playing. /// </summary> public bool Playing { get { return playing; } } /// <summary> /// Starts a new instance of a sound. /// </summary> /// <param name="format">Format of the sound</param> /// <param name="buffer">Buffer holding sound data</param> internal SoundInstance(WaveFormat format, AudioBuffer buffer) { source = new SourceVoice(Audio.Device, format); source.BufferEnd += (s, e) => playing = false; source.Start(); source.SubmitSourceBuffer(buffer); // THIS IS WHERE THE EXCEPTION IS THROWN playing = true; } /// <summary> /// Releases memory used by the instance. /// </summary> internal void Dispose() { source.Dispose(); } } The exception occurs on line 156 when I am playing the sound: source.SubmitSourceBuffer(buffer);

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  • Executive overview of Oracle Fusion Applications in 1-day from your desktop

    - by mseika
    Designed from the ground up using the latest technology advances and incorporating the best practices gathered from Oracle's thousands of customers, Oracle Fusion Applications are 100% open-standards-based business applications that set a new standard for the way we innovate, work, and adopt technology. Learn more about them: Oracle University has scheduled a 1–day executive overview as a Live Virtual Class on the following dates: · 18 November · 22 November · 1 December · 2 December Your OPN discount applies to the standard price shown on the website! New In Class and Online dates will be shared on education.oracle.com. Book online or contact your local Oracle University representative for scheduling requests and more information.

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  • Quickly and Python Twisted

    - by Aaron
    I am creating a Quickly application that makes use of Python Twisted. When the user launches a window, I want to start the Twisted server I wrote. However, when I do this, it freezes the GUI, because the reactor.run method is constantly running after it is started. I need a way to start the Twisted reactor in its own thread, so that the GUI will continue to operate while the reactor is running. I have read about using Twisted with pyGTK in the Twisted documentation, but I am not sure how I would accomplish this with a Quickly application. What is the best way to start my Twisted server when a window opens without freezing the GUI? Update: My if __name__ == '__main__' statement at the end of my dialog file is: print 'Preparing GLib' GLib.idle_add(before_running) print 'Staring Reactor' from twisted.internet import reactor reactor.run()` I have imported and installed twisted.gtk3reactor earlier on in the file. The before_running method contains dialog = ClientDialog() and dialog.show, as well as the rest of the code I want to run when the dialog opens.

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  • Caller Info Attributes in C# 5.0

    - by Jalpesh P. Vadgama
    In c# 5.0 Microsoft has introduced a Caller information attribute. It’s a new feature that is introduced in C# 5.0 and very useful if you want to log your code activities. With the help of this you can implement the log functionality very easily. It can help any programmer in tracing, debugging and diagnostic of any application. With the help of Caller Information we can get following information over there. CallerFilePathAttribute: With help of  this attribute we can get full path of source file that contains caller. This will be file path from which contains caller at compile time. CallerLineNumberAttribute:  With the help of this attribute we can get line number of source file which the method is called. CallerMemberNameAttribute: With the help of this attribute we can get the method or property name of the caller. Read more

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  • Naming convention: Final fields (not static)

    - by Zeeker
    Today I had a discussion with a co-worker about the naming of final fields in Java classes. In his opionion final fields should also be considered constants since their values won't change after the creation of the instance. This would lead to the following naming convention for final fields: public class Foo { private static final String BLA_BLA = "bla"; private final String BAR_BATZ; ... } In my opinion only static final fields should be considered constants while fields which are only final should follow the usual camelCase naming convention. public class Foo { private static final String BLA = "bla"; private final String barBatz; ... } Now I'm a bit uncertain since he is a far more experienced programmer than I am and I usually agree with his opinions and consider him a very good developer. Any input on this?

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  • Best practices for upgrading user data when updating versions of software

    - by Javy
    In my code I check the current version of the software on launch and compare it to the version stored in the user's data file(s). If the version is newer, then I call different methods to update the old data to the newer data version, if necessary. I usually have to make a new method to convert the data with each update that changes user data in some way, and cannot remove the old ones in case there was someone who missed an update. So the app must be able to go through each method call and update their data until they get their data current. With larger data sets, this could be a problem. In addition, I recently had a brief discussion with another StackOverflow user this and he indicated he always appended a date stamp to the filename to manage data versions, although his reasoning as to why this was better than storing the version data in the file itself was unclear. Since I've rarely seen management of user data versions in books I've read, I'm curious what are the best practices for naming user data files and procedures for updating older data to newer versions.

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  • Should all, none, or some overridden methods call Super?

    - by JoJo
    When designing a class, how do you decide when all overridden methods should call super or when none of the overridden methods should call super? Also, is it considered bad practice if your code logic requires a mixture of supered and non-supered methods like the Javascript example below? ChildClass = new Class.create(ParentClass, { /** * @Override */ initialize: function($super) { $super(); this.foo = 99; }, /** * @Override */ methodOne: function($super) { $super(); this.foo++; }, /** * @Override */ methodTwo: function($super) { this.foo--; } }); After delving into the iPhone and Android SDKs, I noticed that super must be called on every overridden method, or else the program will crash because something wouldn't get initialized. When deriving from a template/delegate, none of the methods are supered (obviously). So what exactly are these "je ne sais quoi" qualities that determine whether a all, none, or some overriden methods should call super?

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  • Which torrent client has command line arguments to start/stop downloads?

    - by virpara
    first of all, I want to create shell script to start/stop downloads in torrent client. I don't need CLI but if you know how I can do that with CLI using shell script then it is okay. I use jDownloader which is GUI based application but has some command line arguments as below which I use to start/stop download. -h/--help Show this help message -a/--add-link(s) Add links -co/--add-container(s) Add containers -d/--start-download Start download -D/--stop-download Stop download -H/--hide Don't open Linkgrabber when adding Links -m/--minimize Minimize download window -f/--focus Get jD to foreground/focus -s/--show Show JAC prepared captchas -t/--train Train a JAC method -r/--reconnect Perform a Reconnect -C/--captcha <filepath or url> <method> Get code from image using JAntiCaptcha -p/--add-password(s) Add passwords -n --new-instance Force new instance if another jD is running So I can easily start/stop download as follows, jdownloader --start-download jdownloader --stop-download now I want torrent client to do that through shell script.

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  • MVC shared model different required fields on different type

    - by kurasa
    I have a model called Car and depending on what type of Car the user select the view is presented differently. For example the user selects from a grid of different cars and depending if it is a Volvo or a Kia or a Ford the view must allow different fields to be editable. For example with a Volvo the color is editable and is mandatory but with a Kia it is not. I would like to use the one Car class to bind the view but want the client side validation to pick up the required fields based on what type of car. I want to go only to one Action method for the Update what is a good way to approach this problem...? create a base class and inherit from it? will this give me binding problems..?

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  • Antenna Aligner Part 5: Devil is in the detail

    - by Chris George
    "The first 90% of a project takes 90% of the time and the last 10% takes the another 200%"  (excerpt from onista) Now that I have a working app (more or less), it's time to make it pretty and slick. I can't stress enough how useful it is to get other people using your software, and my simple app is no exception. I handed my iPhone to a couple of my colleagues at Red Gate and asked them to use it and give me feedback. Immediately it became apparent that the delay between the list page being shown and the list being drawn was too long, and everyone who tried the app clicked on the "Recalculate" button before it had finished. Similarly, selecting a transmitter heralded a delay before the compass page appeared with similar consequences. All users expected there to be some sort of feedback/spinny etc. to show them it is actually doing something. In a similar vein although for opposite reasons, clicking the Recalculate button did indeed recalculate the available transmitters and redraw them, but it did this too fast! One or two users commented that they didn't know if it had done anything. All of these issues resulted in similar solutions; implement a waiting spinny. Thankfully, jquery mobile has one built in, primarily used for ajax operations. Not wishing to bore you with the many many iterations I went through trying to get this to work, I'll just give you my solution! (Seriously, I was working on this most evenings for at least a week!) The final solution for the recalculate problem came in the form of the code below. $(document).on("click", ".show-page-loading-msg", function () {            var $this = $(this),                theme = $this.jqmData("theme") ||                        $.mobile.loadingMessageTheme;            $.mobile.showPageLoadingMsg(theme, "recalculating", false);            setTimeout(function ()                           { $.mobile.hidePageLoadingMsg(); }, 2000);            getLocationData();        })        .on("click", ".hide-page-loading-msg", function () {              $.mobile.hidePageLoadingMsg();        }); The spinny is activated by setting the class of a button (for example) to the 'show-page-loading-msg' class. &lt;a data-role="button" class="show-page-loading-msg"Recalculate This means the code above is fired, calling the showPageLoadingMsg on the document.mobile object. Then, after a 2 second timeout, it calls the hidePageLoadingMsg() function. Supposedly, it should show "recalculating" underneath the spinny, but I've not got that to work. I'm wondering if there is a problem with the jquery mobile implementation. Anyway, it doesn't really matter, it's the principle I'm after, and I now have spinnys!

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  • Accessing managers from game entities/components

    - by Boreal
    I'm designing an entity-component engine in C# right now, and all components need to have access to the global event manager, which sends off inter-entity events (every entity also has a local event manager). I'd like to be able to simply call functions like this: GlobalEventManager.Publish("Foo", new EventData()); GlobalEventManager.Subscribe("Bar", OnBarEvent); without having to do this: class HealthComponent { private EventManager globalEventManager; public HealthComponent(EventManager gEM) { globalEventManager = gEM; } } // later on... EventManager globalEventManager = new EventManager(); Entity playerEntity = new Entity(); playerEntity.AddComponent(new HealthComponent(globalEventManager)); How can I accomplish this? EDIT: I solved it by creating a singleton called GlobalEventManager. It derives from the local EventManager class and I use it like this: GlobalEventManager.Instance.Publish("Foo", new EventData());

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  • Launching a URL from an OOB Silverlight Application

    So I'm working on this code browser mostly to help me with my fading memory. In the app I want to be able to launch a url. So I do my normal thing and put a line of code that looks like this:System.Windows.Browser.HtmlPage.Window.Navigate(new Uri(ThisURI), "_blank");I was agast when I realized that this didn't work, for that matter it didn't even blow... grr... but with a bit of research I found that the hyper link button worked so a ended up making a little class like this:public class MyHyperLink...Did you know that DotNetSlackers also publishes .net articles written by top known .net Authors? We already have over 80 articles in several categories including Silverlight. Take a look: here.

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  • Get collision details from Rectangle.Intersects()

    - by Daniel Ribeiro
    I have a Breakout game in which, at some point, I detect the collision between the ball and the paddle with something like this: // Ball class rectangle.Intersects(paddle.Rectangle); Is there any way I can get the exact coordinates of the collision, or any details about it, with the current XNA API? I thought of doing some basic calculations, such as comparing the exact coordinates of each object on the moment of the collision. It would look something like this: // Ball class if((rectangle.X - paddle.Rectangle.X) < (paddle.Rectangle.Width / 2)) // Collision happened on the left side else // Collision happened on the right side But I'm not sure this is the correct way to do it. Do you guys have any tips on maybe an engine I might have to use to achieve that? Or even good coding practices using this method?

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  • Should I extract specific functionality into a function and why?

    - by john smith optional
    I have a large method which does 3 tasks, each of them can be extracted into a separate function. If I'll make an additional functions for each of that tasks, will it make my code better or worse and why? Edit: Obviously, it'll make less lines of code in the main function, but there'll be additional function declarations, so my class will have additional methods, which I believe isn't good, because it'll make the class more complex. Edit2: Should I do that before I wrote all the code or should I leave it until everything is done and then extract functions?

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  • Control external monitor brightness

    - by remi
    Hello Ubuntu community, I can control the brightness of my DELL U2713HM connected with DisplayPort via the command: ddccontrol -p -r 0x10 -w 53 where in this example the number 53 represents the brightness level (range 0 to 100). But I don't know how to link the command to my brightness keys on my keyboard. I searched already, but just found answers to integrated laptop screens. In /sys/class/backlight is the folder acpi_video0 with some subfolders and files. The file actual_brightness contains a number from 0 to 20, which is changing when I press the brightness keys. How do I get my external monitor listed as a device in /sys/class/backlight ? PS: I am running a fresh Ubuntu 12.10 install with integrated graphics Intel HD4000.

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  • LINQ and ArcObjects

    - by Marko Apfel
    Motivation LINQ (language integrated query) is a component of the Microsoft. NET Framework since version 3.5. It allows a SQL-like query to various data sources such as SQL, XML etc. Like SQL also LINQ to SQL provides a declarative notation of problem solving – i.e. you don’t need describe in detail how a task could be solved, you describe what to be solved at all. This frees the developer from error-prone iterator constructs. Ideally, of course, would be to access features with this way. Then this construct is conceivable: var largeFeatures = from feature in features where (feature.GetValue("SHAPE_Area").ToDouble() > 3000) select feature; or its equivalent as a lambda expression: var largeFeatures = features.Where(feature => (feature.GetValue("SHAPE_Area").ToDouble() > 3000)); This requires an appropriate provider, which manages the corresponding iterator logic. This is easier than you might think at first sight - you have to deliver only the desired entities as IEnumerable<IFeature>. LINQ automatically establishes a state machine in the background, whose execution is delayed (deferred execution) - when you are really request entities (foreach, Count (), ToList (), ..) an instantiation processing takes place, although it was already created at a completely different place. Especially in multiple iteration through entities in the first debuggings you are rubbing your eyes when the execution pointer jumps magically back in the iterator logic. Realization A very concise logic for constructing IEnumerable<IFeature> can be achieved by running through a IFeatureCursor. You return each feature via yield. For an easier usage I have put the logic in an extension method Getfeatures() for IFeatureClass: public static IEnumerable<IFeature> GetFeatures(this IFeatureClass featureClass, IQueryFilter queryFilter, RecyclingPolicy policy) { IFeatureCursor featureCursor = featureClass.Search(queryFilter, RecyclingPolicy.Recycle == policy); IFeature feature; while (null != (feature = featureCursor.NextFeature())) { yield return feature; } //this is skipped in unit tests with cursor-mock if (Marshal.IsComObject(featureCursor)) { Marshal.ReleaseComObject(featureCursor); } } So you can now easily generate the IEnumerable<IFeature>: IEnumerable<IFeature> features = _featureClass.GetFeatures(RecyclingPolicy.DoNotRecycle); You have to be careful with the recycling cursor. After a delayed execution in the same context it is not a good idea to re-iterated on the features. In this case only the content of the last (recycled) features is provided and all the features are the same in the second set. Therefore, this expression would be critical: largeFeatures.ToList(). ForEach(feature => Debug.WriteLine(feature.OID)); because ToList() iterates once through the list and so the the cursor was once moved through the features. So the extension method ForEach() always delivers the same feature. In such situations, you must not use a recycling cursor. Repeated executions of ForEach() is not a problem, because for every time the state machine is re-instantiated and thus the cursor runs again - that's the magic already mentioned above. Perspective Now you can also go one step further and realize your own implementation for the interface IEnumerable<IFeature>. This requires that only the method and property to access the enumerator have to be programmed. In the enumerator himself in the Reset() method you organize the re-executing of the search. This could be archived with an appropriate delegate in the constructor: new FeatureEnumerator<IFeatureclass>(_featureClass, featureClass => featureClass.Search(_filter, isRecyclingCursor)); which is called in Reset(): public void Reset() { _featureCursor = _resetCursor(_t); } In this manner, enumerators for completely different scenarios could be implemented, which are used on the client side completely identical like described above. Thus cursors, selection sets, etc. merge into a single matter and the reusability of code is increasing immensely. On top of that in automated unit tests an IEnumerable could be mocked very easily - a major step towards better software quality. Conclusion Nevertheless, caution should be exercised with these constructs in performance-relevant queries. Because of managing a state machine in the background, a lot of overhead is created. The processing costs additional time - about 20 to 100 percent. In addition, working without a recycling cursor is fast a performance gap. However declarative LINQ code is much more elegant, flawless and easy to maintain than manually iterating, compare and establish a list of results. The code size is reduced according to experience an average of 75 to 90 percent! So I like to wait a few milliseconds longer. As so often it has to be balanced between maintainability and performance - which for me is gaining in priority maintainability. In times of multi-core processors, the processing time of most business processes is anyway not dominated by code execution but by waiting for user input. Demo source code The source code for this prototype with several unit tests, you can download here: https://github.com/esride-apf/Linq2ArcObjects. .

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  • Enum types, FlagsAttribute & Zero value – Part 2

    - by nmgomes
    In my previous post I wrote about why you should pay attention when using enum value Zero. After reading that post you are probably thinking like Benjamin Roux: Why don’t you start the enum values at 0x1? Well I could, but doing that I lose the ability to have Sync and Async mutually exclusive by design. Take a look at the following enum types: [Flags] public enum OperationMode1 { Async = 0x1, Sync = 0x2, Parent = 0x4 } [Flags] public enum OperationMode2 { Async = 0x0, Sync = 0x1, Parent = 0x2 } To achieve mutually exclusion between Sync and Async values using OperationMode1 you would have to operate both values: protected void CheckMainOperarionMode(OperationMode1 mode) { switch (mode) { case (OperationMode1.Async | OperationMode1.Sync | OperationMode1.Parent): case (OperationMode1.Async | OperationMode1.Sync): throw new InvalidOperationException("Cannot be Sync and Async simultaneous"); break; case (OperationMode1.Async | OperationMode1.Parent): case (OperationMode1.Async): break; case (OperationMode1.Sync | OperationMode1.Parent): case (OperationMode1.Sync): break; default: throw new InvalidOperationException("No default mode specified"); } } but this is a by design constraint in OperationMode2. Why? Simply because 0x0 is the neutral element for the bitwise OR operation. Knowing this singularity, replacing and simplifying the previous method, you get: protected void CheckMainOperarionMode(OperationMode2 mode) { switch (mode) { case (OperationMode2.Sync | OperationMode2.Parent): case (OperationMode2.Sync): break; case (OperationMode2.Parent): default: break; } This means that: if both Sync and Async values are specified Sync value always win (Zero is the neutral element for bitwise OR operation) if no Sync value specified, the Async method is used. Here is the final method implementation: protected void CheckMainOperarionMode(OperationMode2 mode) { if (mode & OperationMode2.Sync == OperationMode2.Sync) { } else { } } All content above prove that Async value (0x0) is useless from the arithmetic perspective, but, without it we lose readability. The following IF statements are logically equals but the first is definitely more readable: if (OperationMode2.Async | OperationMode2.Parent) { } if (OperationMode2.Parent) { } Here’s another example where you can see the benefits of 0x0 value, the default value can be used explicitly. <my:Control runat="server" Mode="Async,Parent"> <my:Control runat="server" Mode="Parent">

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  • Trying to make a universe [on hold]

    - by caters
    I am wanting to program a universe so that it starts with a big bang and atoms form and then molecules form and stars start to form and planets start to form and then moons around those planets. I have a few questions. If 400 IPMUs(In Program Mass Units) = 1 solar mass than how would I calculate the number of IPMUs for a spectral class of star given the range of solar masses for a main sequence star in that spectral class? How can I have planets not look like stars? Since whether it is a subdwarf, main sequence star, subgiant, giant, bright giant, supergiant, or hypergiant is mainly dependent on the radius and luminosity how can I have the radius and luminosity independent of the mass?

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  • Oracle University Partner Enablement Update (4th April)

    - by swalker
    Get ready for Fusion Applications Implementations Oracle University has scheduled the first Oracle Fusion Applications Implementation courses. To view see: Italy France The Netherlands UK If you can’t find an In Class event in a country near you, why don’t you try a Live Virtual Class? View the UK link above and check out the Location: Online. All courses can be booked via the websites. For more information, assistance in booking and scheduling requests contact your local Oracle University Service Desk. Stay Connected to Oracle University: LinkedIn OracleMix Twitter Facebook Google+

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  • Circle vs Edge collision detection / resolution

    - by topheman
    I made a javascript class Ball.js that handles physics interactions betweens balls as well as painting. In the v1.0, the ball vs ball collision detection and resolution is well handled. In the next version (v2), I'm trying to add edgeCollision handling. I'm having some problems, maybe you will be able to help me. All the v2 branch source code is on github repository : https://github.com/topheman/Ball.js/tree/v2 The v2 demos (where you can see the bug I will be talking about) : http://labs.topheman.com/Ball-v2/#help As you will see on the demo, I have two major problems that I'm having a really hard time to solve on Ball.js : method resolveEdgeCollision : bounce angle is inconsistent method checkEdgeCollision : if the ball's velocity (the length that it runs each frame) is higher than its diameter, eventually, it will pass through an edge, without triggering any collision Any Ideas ?...

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  • Is Ruby on Rails' Active Record an example of Aspect-Oriented Programming?

    - by B Seven
    From Clean Code, about Cross-Cutting Concerns: Note that concerns like persistence tend to cut across the natural object boundaries of a domain. You want to persist all your objects using generally the same strategy, for example, using a particular DBMS... Is Active Record an example of aspect-oriented programming? In AOP, modular constructs called aspects specify which points in the system should have their behavior modified in some consistent way to support a particular concern. This specification is done using a succinct declarative or programmatic mechanism. If Active Record is an example of AOP, what is the "aspect"? Is it the class declaration that inherits from Active Record? class Foo < ActiveRecord::Base

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  • Ubuntu 13.04 ERROR: /etc/apt/sources.list not found

    - by Richard Riley
    So, I tried uninstalling the LAMP stack I had following the Ubuntu documentation for it. I also manually removed dbconfig-common. Now, I'm unable to run apt-get update. When I do, I get the error message: E: The method driver /usr/lib/apt/methods/htp could not be found. After some digging, I've discovered that I no longer even have an /etc/apt/sources.list file. Also, I've received an error, when trying to run: sudo tasksel install lamp-server That aptitude can not be found. Does anyone have an idea of what I can do? I'm not able to find any documentation online that works - all the documentation out there is dated and no longer (or will not) work with 13.04. I followed this link previously prior to posting my question and it did not work for me: How do I fix a "E: The method driver /usr/lib/apt/methods/http could not be found." error?

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  • C# Preprocessor Directives

    - by MarkPearl
    Going back to my old c++ days at university where we had all our code littered with preprocessor directives - I thought it made the code ugly and could never understand why it was useful. Today though I found a use in my C# application. The scenario – I had made various security levels in my application and tied my XAML to the levels by set by static accessors in code. An example of my XAML code for a Combobox to be enabled would be as follows… <ComboBox IsEnabled="{x:Static security:Security.SecurityCanEditDebtor}" />   And then I would have a static method like this… public static bool SecurityCanEditDebtorPostalAddress { get { if (SecurityCanEditDebtorPostalAddress) { return true; } else { return false; } } } My only problem was that my XAML did not like the if statement – which meant that while my code worked during runtime, during design time in VS2010 it gave some horrible error like… NullReferenceException was thrown on “StatiucExtension”: Exception has been thrown by the target of an invocation… If however my C# method was changed to something like this… public static bool SecurityCanEditDebtorPostalAddress { get { return true; } }   My XAML viewer would be happy. But of course this would bypass my security… <Drum Roll> Welcome preprocessor directives… what I wanted was during my design experience to totally remove the “if” code so that my accessor would return true and not have any if statements, but when I release my project to the big open world, I want the code to have the is statement. With a bit of searching I found the relevant MSDN sample and my code now looks like this… public static bool SecurityCanEditDebtorPostalAddress { get { #if DEBUG return true; #else if (Settings.GetInstance().CurrentUser.SecurityCanEditDebtorPostalAddress) { return true; } else { return false; } #endif } }   Not the prettiest beast, but it works. Basically what is being said here is that during my debug mode compile my code with just the code between the #if … #else block, but what I can now do is if I want to universally switch everything to the “if else” statement, I just go to my project properties –> Build and change the “Debug” flag as illustrated in the picture below. Also note that you can define your own conditional compilation symbols, and if you even wanted to you could skip the whole properties page and define them in code using the #define & #undef directives. So while I don’t like the way the code works and would like to look more into AOP and compare it to this method, it works for now.

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