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  • Algorithm to generate multifaced cube?

    - by OnePie
    Are there any elegant soloution to generate a simple-six sided cube, where each cube is made out of more than one face? The method I have used ended up a horrible and complicated mess of logic that is imopssible to follow and most likely to maintain. The algorithm should not generate reduntant vertices, and should output the indice list for the mesh as well. The reason I need this is that the cubes vertices will be deformed depending on various factors, meaning that a simple six-faced cube will nto do.

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  • Undocumented Query Plans: Equality Comparisons

    - by Paul White
    The diagram below shows two data sets, with differences highlighted: To find changed rows using TSQL, we might write a query like this: The logic is clear: join rows from the two sets together on the primary key column, and return rows where a change has occurred in one or more data columns.  Unfortunately, this query only finds one of the expected four rows: The problem, of course, is that our query does not correctly handle NULLs.  The ‘not equal to’ operators <> and != do not evaluate...(read more)

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  • When you should and should not use the 'new' keyword?

    - by skizeey
    I watched a Google Tech Talk presentation on Unit Testing, given by Misko Hevery, and he said to avoid using the new keyword in business logic code. I wrote a program, and I did end up using the new keyword here and there, but they were mostly for instantiating objects that hold data (ie, they didn't have any functions or methods). I'm wondering, did I do something wrong when I used the new keyword for my program. And where can we break that 'rule'?

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  • Accessing Repositories from Domain

    - by Paul T Davies
    Say we have a task logging system, when a task is logged, the user specifies a category and the task defaults to a status of 'Outstanding'. Assume in this instance that Category and Status have to be implemented as entities. Normally I would do this: Application Layer: public class TaskService { //... public void Add(Guid categoryId, string description) { var category = _categoryRepository.GetById(categoryId); var status = _statusRepository.GetById(Constants.Status.OutstandingId); var task = Task.Create(category, status, description); _taskRepository.Save(task); } } Entity: public class Task { //... public static void Create(Category category, Status status, string description) { return new Task { Category = category, Status = status, Description = descrtiption }; } } I do it like this because I am consistently told that entities should not access the repositories, but it would make much more sense to me if I did this: Entity: public class Task { //... public static void Create(Category category, string description) { return new Task { Category = category, Status = _statusRepository.GetById(Constants.Status.OutstandingId), Description = descrtiption }; } } The status repository is dependecy injected anyway, so there is no real dependency, and this feels more to me thike it is the domain that is making thedecision that a task defaults to outstanding. The previous version feels like it is the application layeer making that decision. Any why are repository contracts often in the domain if this should not be a posibility? Here is a more extreme example, here the domain decides urgency: Entity: public class Task { //... public static void Create(Category category, string description) { var task = new Task { Category = category, Status = _statusRepository.GetById(Constants.Status.OutstandingId), Description = descrtiption }; if(someCondition) { if(someValue > anotherValue) { task.Urgency = _urgencyRepository.GetById (Constants.Urgency.UrgentId); } else { task.Urgency = _urgencyRepository.GetById (Constants.Urgency.SemiUrgentId); } } else { task.Urgency = _urgencyRepository.GetById (Constants.Urgency.NotId); } return task; } } There is no way you would want to pass in all possible versions of Urgency, and no way you would want to calculate this business logic in the application layer, so surely this would be the most appropriate way? So is this a valid reason to access repositories from the domain?

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  • The C++ web stack, is there one?

    - by NimChimpsky
    Java would be jsps and servlets (or a framework such as Spring) running on the JVM and tomcat (or glassfish etc). C# would be asp and C# running on dot.net framework and IIS ? (I have no experience with this please correct and improve my terminology) Is there an equivalent for C++ ? I could happily call some C++ from a java servlet/controller but was wondering if there are existing frameworks and libraries out there specifically for creating business logic in C++ with a web front end.

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  • Easy Profiling Point Insertion

    - by Geertjan
    One really excellent feature of NetBeans IDE is its Profiler. What's especially cool is that you can analyze code fragments, that is, you can right-click in a Java file and then choose Profiling | Insert Profiling Point. When you do that, you're able to analyze code fragments, i.e., from one statement to another statement, e.g., how long a particular piece of code takes to execute: https://netbeans.org/kb/docs/java/profiler-profilingpoints.html However, right-clicking a Java file and then going all the way down a longish list of menu items, to find "Profiling", and then "Insert Profiling Point" is a lot less easy than right-clicking in the sidebar (known as the glyphgutter) and then setting a profiling point in exactly the same way as a breakpoint: That's much easier and more intuitive and makes it far more likely that I'll use the Profiler at all. Once profiling points have been set then, as always, another menu item is added for managing the profiling point: To achieve this, I added the following to the "layer.xml" file: <folder name="Editors"> <folder name="AnnotationTypes"> <file name="profiler.xml" url="profiler.xml"/> <folder name="ProfilerActions"> <file name="org-netbeans-modules-profiler-ppoints-ui-InsertProfilingPointAction.shadow"> <attr name="originalFile" stringvalue="Actions/Profile/org-netbeans-modules-profiler-ppoints-ui-InsertProfilingPointAction.instance"/> <attr name="position" intvalue="300"/> </file> </folder> </folder> </folder> Notice that a "profiler.xml" file is referred to in the above, in the same location as where the "layer.xml" file is found. Here is the content: <!DOCTYPE type PUBLIC '-//NetBeans//DTD annotation type 1.1//EN' 'http://www.netbeans.org/dtds/annotation-type-1_1.dtd'> <type name='editor-profiler' description_key='HINT_PROFILER' localizing_bundle='org.netbeans.eppi.Bundle' visible='true' type='line' actions='ProfilerActions' severity='ok' browseable='false'/> Only disadvantage is that this registers the profiling point insertion in the glyphgutter for all file types. But that's true for the debugger too, i.e., there's no MIME type specific glyphgutter, instead, it is shared by all MIME types. Little bit confusing that the profiler point insertion can now, in theory, be set for all MIME types, but that's also true for the debugger, even though it doesn't apply to all MIME types. That probably explains why the profiling point insertion can only be done, officially, from the right-click popup menu of Java files, i.e., the developers wanted to avoid confusion and make it available to Java files only. However, I think that, since I'm already aware that I can't set the Java debugger in an HTML file, I'm also aware that the Java profiler can't be set that way as well. If you find this useful too, you can download and install the NBM from here: http://plugins.netbeans.org/plugin/55002

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  • Unit testing in Django

    - by acjohnson55
    I'm really struggling to write effective unit tests for a large Django project. I have reasonably good test coverage, but I've come to realize that the tests I've been writing are definitely integration/acceptance tests, not unit tests at all, and I have critical portions of my application that are not being tested effectively. I want to fix this ASAP. Here's my problem. My schema is deeply relational, and heavily time-oriented, giving my model object high internal coupling and lots of state. Many of my model methods query based on time intervals, and I've got a lot of auto_now_add going on in timestamped fields. So take a method that looks like this for example: def summary(self, startTime=None, endTime=None): # ... logic to assign a proper start and end time # if none was provided, probably using datetime.now() objects = self.related_model_set.manager_method.filter(...) return sum(object.key_method(startTime, endTime) for object in objects) How does one approach testing something like this? Here's where I am so far. It occurs to me that the unit testing objective should be given some mocked behavior by key_method on its arguments, is summary correctly filtering/aggregating to produce a correct result? Mocking datetime.now() is straightforward enough, but how can I mock out the rest of the behavior? I could use fixtures, but I've heard pros and cons of using fixtures for building my data (poor maintainability being a con that hits home for me). I could also setup my data through the ORM, but that can be limiting, because then I have to create related objects as well. And the ORM doesn't let you mess with auto_now_add fields manually. Mocking the ORM is another option, but not only is it tricky to mock deeply nested ORM methods, but the logic in the ORM code gets mocked out of the test, and mocking seems to make the test really dependent on the internals and dependencies of the function-under-test. The toughest nuts to crack seem to be the functions like this, that sit on a few layers of models and lower-level functions and are very dependent on the time, even though these functions may not be super complicated. My overall problem is that no matter how I seem to slice it, my tests are looking way more complex than the functions they are testing.

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  • SQL SERVER – Storing 64-bit Unsigned Integer Value in Database

    - by Pinal Dave
    Here is a very interesting question I received in an email just another day. Some questions just are so good that it makes me wonder how come I have not faced it first hand. Anyway here is the question - “Pinal, I am migrating my database from MySQL to SQL Server and I have faced unique situation. I have been using Unsigned 64-bit integer in MySQL but when I try to migrate that column to SQL Server, I am facing an issue as there is no datatype which I find appropriate for my column. It is now too late to change the datatype and I need immediate solution. One chain of thought was to change the data type of the column from Unsigned 64-bit (BIGINT) to VARCHAR(n) but that will just change the data type for me such that I will face quite a lot of performance related issues in future. In SQL Server we also have the BIGINT data type but that is Signed 64-bit datatype. BIGINT datatype in SQL Server have range of -2^63 (-9,223,372,036,854,775,808) to 2^63-1 (9,223,372,036,854,775,807). However, my digit is much larger than this number. Is there anyway, I can store my big 64-bit Unsigned Integer without loosing much of the performance of by converting it to VARCHAR.” Very interesting question, for the sake of the argument, we can ask user that there should be no need of such a big number or if you are taking about identity column I really doubt that if your table will grow beyond this table. Here the real question which I found interesting was how to store 64-bit unsigned integer value in SQL Server without converting it to String data type. After thinking a bit, I found a fairly simple answer. I can use NUMERIC data type. I can use NUMERIC(20) datatype for 64-bit unsigned integer value, NUMERIC(10) datatype for 32-bit unsigned integer value and NUMERIC(5) datatype for 16-bit unsigned integer value. Numeric datatype supports 38 maximum of 38 precision. Now here is another thing to keep in mind. Using NUMERIC datatype will indeed accept the 64-bit unsigned integer but in future if you try to enter negative value, it will also allow the same. Hence, you will need to put any additional constraint over column to only accept positive integer there. Here is another big concern, SQL Server will store the number as numeric and will treat that as a positive integer for all the practical purpose. You will have to write in your application logic to interpret that as a 64-bit Unsigned Integer. On another side if you are using unsigned integers in your application, there are good chance that you already have logic taking care of the same. Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: PostADay, SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, T SQL, Technology Tagged: SQL Datatype

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  • How to handle lookup data in a C# ASP.Net MVC4 application?

    - by Jim
    I am writing an MVC4 application to track documents we have on file for our clients. I'm using code first, and have created models for my objects (Company, Document, etc...). I am now faced with the topic of document expiration. Business logic dictates certain documents will expire a set number of days past the document date. For example, Document A might expire in 180 days, Document 2 in 365 days, etc... I have a class for my documents as shown below (simplified for this example). What is the best way for me to create a lookup for expiration values? I want to specify documents of type DocumentA expire in 30 days, type DocumentB expire in 75 days, etc... I can think of a few ways to do this: Lookup table in the database I can query New property in my class (DaysValidFor) which has a custom getter that returns different values based on the DocumentType A method that takes in the document type and returns the number of days and I'm sure there are other ways I'm not even thinking of. My main concern is a) not violating any best practices and b) maintainability. Are there any pros/cons I need to be aware of for the above options, or is this a case of "just pick one and run with it"? One last thought, right now the number of days is a value that does not need to be stored anywhere on a per-document basis -- however, it is possible that business logic will change this (i.e., DocumentA's are 30 days expiration by default, but this DocumentA associated with Company XYZ will be 60 days because we like them). In that case, is a property in the Document class the best way to go, seeing as I need to add that field to the DB? namespace Models { // Types of documents to track public enum DocumentType { DocumentA, DocumentB, DocumentC // etc... } // Document model public class Document { public int DocumentID { get; set; } // Foreign key to companies public int CompanyID { get; set; } public DocumentType DocumentType { get; set; } // Helper to translate enum's value to an integer for DB storage [Column("DocumentType")] public int DocumentTypeInt { get { return (int)this.DocumentType; } set { this.DocumentType = (DocumentType)value; } } [DataType(DataType.Date)] [DisplayFormat(DataFormatString = "{0:MM-dd-yyyy}", ApplyFormatInEditMode = true)] public DateTime DocumentDate { get; set; } // Navigation properties public virtual Company Company { get; set; } } }

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  • Advantages and disadvantages of building a single page web application

    - by ryanzec
    I'm nearing the end of a prototyping/proof of concept phase for a side project I'm working on, and trying to decide on some larger scale application design decisions. The app is a project management system tailored more towards the agile development process. One of the decisions I need to make is whether or not to go with a traditional multi-page application or a single page application. Currently my prototype is a traditional multi-page setup, however I have been looking at backbone.js to clean up and apply some structure to my Javascript (jQuery) code. It seems like while backbone.js can be used in multi-page applications, it shines more with single page applications. I am trying to come up with a list of advantages and disadvantages of using a single page application design approach. So far I have: Advantages All data has to be available via some sort of API - this is a big advantage for my use case as I want to have an API to my application anyway. Right now about 60-70% of my calls to get/update data are done through a REST API. Doing a single page application will allow me to better test my REST API since the application itself will use it. It also means that as the application grows, the API itself will grow since that is what the application uses; no need to maintain the API as an add-on to the application. More responsive application - since all data loaded after the initial page is kept to a minimum and transmitted in a compact format (like JSON), data requests should generally be faster, and the server will do slightly less processing. Disadvantages Duplication of code - for example, model code. I am going to have to create models both on the server side (PHP in this case) and the client side in Javascript. Business logic in Javascript - I can't give any concrete examples on why this would be bad but it just doesn't feel right to me having business logic in Javascript that anyone can read. Javascript memory leaks - since the page never reloads, Javascript memory leaks can happen, and I would not even know where to begin to debug them. There are also other things that are kind of double edged swords. For example, with single page applications, the data processed for each request can be a lot less since the application will be asking for the minimum data it needs for the particular request, however it also means that there could be a lot more small request to the server. I'm not sure if that is a good or bad thing. What are some of the advantages and disadvantages of single page web applications that I should keep in mind when deciding which way I should go for my project?

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  • Why is Spritebatch drawing my Textures out of order?

    - by Andrew
    I just started working with XNA Studio after programming 2D games in java. Because of this, I have absolutely no experience with Spritebatch and sprite sorting. In java, I could just layer the images by calling the draw methods in order. For a while, my Spritebatch was working fine in deferred sorting mode, but when I made a change to one of my textures, it suddenly started drawing them out of order. I have searched for a solution to this problem, but nothing seems to work. I have tried adding layer depths to the sprites and changing the sort mode to BackToFront or FrontToBack or even immediate, but nothing seems to work. Here is my drawing code: protected override void Draw(GameTime gameTime) { GraphicsDevice.Clear(Color.Gray); Game1.spriteBatch.Begin(SpriteSortMode.Deferred, BlendState.AlphaBlend, SamplerState.PointClamp, null, null); for (int x = 0; x < 5; x++) { for (int y = 0; y < 5; y++) { region[x, y].draw(((float)w / aw)); // Draws the Tile-Based background } } player.draw(spriteBatch, ((float)w / aw));//draws the character (This method is where the problem occurs) enemy.draw(spriteBatch, (float)w/aw); // draws a basic enemy Game1.spriteBatch.End(); base.Draw(gameTime); } player.draw method: public void draw(SpriteBatch sb, float ratio){ //draws the player base (The character without hair or equipment) sb.Draw(playerbase[0], new Rectangle((int)(pos.X - (24 * ratio)), (int)(pos.Y - (48 * ratio)), (int)(48 * ratio), (int)(48 * ratio)), new Rectangle(orientation * 48, animFrame * 48, 48, 48), Color.White,0,Vector2.Zero,SpriteEffects.None,0); //draws the player's hair sb.Draw(playerbase[3], new Rectangle((int)(pos.X - (24 * ratio)), (int)(pos.Y - (48 * ratio)), (int)(48 * ratio), (int)(48 * ratio)), new Rectangle(orientation * 48, animFrame * 48, 48, 48), Color.White, 0, Vector2.Zero, SpriteEffects.None, 0); //draws the player's shirt sb.Draw(equipment[0], new Rectangle((int)(pos.X - (24 * ratio)), (int)(pos.Y - (48 * ratio)), (int)(48 * ratio), (int)(48 * ratio)), new Rectangle(orientation * 48, animFrame * 48, 48, 48), Color.White, 0, Vector2.Zero, SpriteEffects.None, 0); //draws the player's pants sb.Draw(equipment[1], new Rectangle((int)(pos.X - (24 * ratio)), (int)(pos.Y - (48 * ratio)), (int)(48 * ratio), (int)(48 * ratio)), new Rectangle(orientation * 48, animFrame * 48, 48, 48), Color.White, 0, Vector2.Zero, SpriteEffects.None, 0); //draws the player's shoes sb.Draw(equipment[2], new Rectangle((int)(pos.X - (24 * ratio)), (int)(pos.Y - (48 * ratio)), (int)(48 * ratio), (int)(48 * ratio)), new Rectangle(orientation * 48, animFrame * 48, 48, 48), Color.White, 0, Vector2.Zero, SpriteEffects.None, 0); } the game has a top-down perspective much like the early legend of zelda games. It draws sections of the texture depending on which direction the character is facing and the animation frame. However, instead of drawing the character in the order the draw methods are called, it ends up drawing the character out of order. Please help me with this problem.

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  • Producing a smooth mesh from density cloud and marching cubes

    - by Wardy
    Based on my results from this question I decided to build myself a 3D noise map containing float values in place of my existing boolean point values. The effect I'm trying to produce is something like this, rather than typical rolling hills; which should explain the "missing cubes" in the image below. If I render my density map in normal "minecraft mode" (1 block per point in the density map) varying the size of the cube based on the value in my density map (floats in the range 0 to 1) I get something like this: I'm now happy that I can produce a density map for the marching cubes algorithm (which will need a little tweaking) but for some reason when I run it through my implementation it's not producing what I expect. My problem is that I'm getting something like the first image in this answer to my previous question, when I want to achieve the effect in the second image. Upon further investigation I can't see how marching cubes does the "move vertex along the edge" type logic (i.e. the difference between the two images on my previous link). I see that it does do some interpolation, but I'm not convinced I have the correct understanding of what I think it should do, because the code in question appears to give the same result regardless of whether I use boolean or float values. I took the code from here which is a C# implementation of marching cubes, but instead of using the MarchingCubesPrimitive I modified it to accept an object of type IDrawable, containing lists for the various collections (vertices, normals, UVs, indices), the logic was otherwise untouched. My understanding is that given a very low isovalue the accuracy level of the surface being rendered should increase, so in short "less 45 degree slows more rolling hills" type mesh output. However this isn't what I'm seeing. Have I missed something or is the implementation flawed and need to be fixed? EDIT: A little more detail on what I am seeing when I "marching cube" the data. Ok so firstly, ignore the fact that the meshes created by the chunks don't "connect" (i'll probably raise another question about this later). Then look at the shaping of the island, it's too ... square, from the voxels rendered as boxes you get the impression there's a clean soft gradual hill and yet from the image there are sharp falling edges even in the most central areas where the gradient in the first image looks the most smooth. The data is "regenerated" each time I run this so no 2 islands come out the same, and it's purely random so not based on noise, but still, how can it look so smooth in 1 image and so not smooth in the other?

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  • IRM and Consumerization

    - by martin.abrahams
    As the season of rampant consumerism draws to its official close on 12th Night, it seems a fitting time to discuss consumerization - whereby technologies from the consumer market, such as the Android and iPad, are adopted by business organizations. I expect many of you will have received a shiny new mobile gadget for Christmas - and will be expecting to use it for work as well as leisure in 2011. In my case, I'm just getting to grips with my first Android phone. This trend developed so much during 2010 that a number of my customers have officially changed their stance on consumer devices - accepting consumerization as something to embrace rather than resist. Clearly, consumerization has significant implications for information control, as corporate data is distributed to consumer devices whether the organization is aware of it or not. I daresay that some DLP solutions can limit distribution to some extent, but this creates a conflict between accepting consumerization and frustrating it. So what does Oracle IRM have to offer the consumerized enterprise? First and foremost, consumerization does not automatically represent great additional risk - if an enterprise seals its sensitive information. Sealed files are encrypted, and that fundamental protection is not affected by copying files to consumer devices. A device might be lost or stolen, and the user might not think to report the loss of a personally owned device, but the data and the enterprise that owns it are protected. Indeed, the consumerization trend is another strong reason for enterprises to deploy IRM - to protect against this expansion of channels by which data might be accidentally exposed. It also enables encryption requirements to be met even though the enterprise does not own the device and cannot enforce device encryption. Moving on to the usage of sealed content on such devices, some of our customers are using virtual desktop solutions such that, in truth, the sealed content is being opened and used on a PC in the normal way, and the user is simply using their device for display purposes. This has several advantages: The sensitive documents are not actually on the devices, so device loss and theft are even less of a worry The enterprise has another layer of control over how and where content is used, as access to the virtual solution involves another layer of authentication and authorization - defence in depth It is a generic solution that means the enterprise does not need to actively support the ever expanding variety of consumer devices - the enterprise just manages some virtual access to traditional systems using something like Citrix or Remote Desktop services. It is a tried and tested way of accessing sealed documents. People have being using Oracle IRM in conjunction with Citrix and Remote Desktop for several years. For some scenarios, we also have the "IRM wrapper" option that provides a simple app for sealing and unsealing content on a range of operating systems. We are busy working on other ways to support the explosion of consumer devices, but this blog is not a proper forum for talking about them at this time. If you are an Oracle IRM customer, we will be pleased to discuss our plans and your requirements with you directly on request. You can be sure that the blog will cover the new capabilities as soon as possible.

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  • Can anyone explain to me what problem Core Data solves?

    - by Curtis Sumpter
    Core Data seems to add a needless layer of complexity. If you want to save data created natively by the user in an app why not just use an object and then write the data all to SQLite or back to a server using a RESTful script if necessary. Android doesn't have Core Data (though if it has something similar I haven't seen it.). What the heck is the point of buggy CD except useless needless overhead for people who can't write SQL or CGI scripts?

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  • DRY and SRP

    - by Timothy Klenke
    Originally posted on: http://geekswithblogs.net/TimothyK/archive/2014/06/11/dry-and-srp.aspxKent Beck’s XP Simplicity Rules (aka Four Rules of Simple Design) are a prioritized list of rules that when applied to your code generally yield a great design.  As you’ll see from the above link the list has slightly evolved over time.  I find today they are usually listed as: All Tests Pass Don’t Repeat Yourself (DRY) Express Intent Minimalistic These are prioritized.  If your code doesn’t work (rule 1) then everything else is forfeit.  Go back to rule one and get the code working before worrying about anything else. Over the years the community have debated whether the priority of rules 2 and 3 should be reversed.  Some say a little duplication in the code is OK as long as it helps express intent.  I’ve debated it myself.  This recent post got me thinking about this again, hence this post.   I don’t think it is fair to compare “Expressing Intent” against “DRY”.  This is a comparison of apples to oranges.  “Expressing Intent” is a principal of code quality.  “Repeating Yourself” is a code smell.  A code smell is merely an indicator that there might be something wrong with the code.  It takes further investigation to determine if a violation of an underlying principal of code quality has actually occurred. For example “using nouns for method names”, “using verbs for property names”, or “using Booleans for parameters” are all code smells that indicate that code probably isn’t doing a good job at expressing intent.  They are usually very good indicators.  But what principle is the code smell of Duplication pointing to and how good of an indicator is it? Duplication in the code base is bad for a couple reasons.  If you need to make a change and that needs to be made in a number of locations it is difficult to know if you have caught all of them.  This can lead to bugs if/when one of those locations is overlooked.  By refactoring the code to remove all duplication there will be left with only one place to change, thereby eliminating this problem. With most projects the code becomes the single source of truth for a project.  If a production code base is inconsistent with a five year old requirements or design document the production code that people are currently living with is usually declared as the current reality (or truth).  Requirement or design documents at this age in a project life cycle are usually of little value. Although comparing production code to external documentation is usually straight forward, duplication within the code base muddles this declaration of truth.  When code is duplicated small discrepancies will creep in between the two copies over time.  The question then becomes which copy is correct?  As different factions debate how the software should work, trust in the software and the team behind it erodes. The code smell of Duplication points to a violation of the “Single Source of Truth” principle.  Let me define that as: A stakeholder’s requirement for a software change should never cause more than one class to change. Violation of the Single Source of Truth principle will always result in duplication in the code.  However, the inverse is not always true.  Duplication in the code does not necessarily indicate that there is a violation of the Single Source of Truth principle. To illustrate this, let’s look at a retail system where the system will (1) send a transaction to a bank and (2) print a receipt for the customer.  Although these are two separate features of the system, they are closely related.  The reason for printing the receipt is usually to provide an audit trail back to the bank transaction.  Both features use the same data:  amount charged, account number, transaction date, customer name, retail store name, and etcetera.  Because both features use much of the same data, there is likely to be a lot of duplication between them.  This duplication can be removed by making both features use the same data access layer. Then start coming the divergent requirements.  The receipt stakeholder wants a change so that the account number has the last few digits masked out to protect the customer’s privacy.  That can be solve with a small IF statement whilst still eliminating all duplication in the system.  Then the bank wants to take a picture of the customer as well as capture their signature and/or PIN number for enhanced security.  Then the receipt owner wants to pull data from a completely different system to report the customer’s loyalty program point total. After a while you realize that the two stakeholders have somewhat similar, but ultimately different responsibilities.  They have their own reasons for pulling the data access layer in different directions.  Then it dawns on you, the Single Responsibility Principle: There should never be more than one reason for a class to change. In this example we have two stakeholders giving two separate reasons for the data access class to change.  It is clear violation of the Single Responsibility Principle.  That’s a problem because it can often lead the project owner pitting the two stakeholders against each other in a vein attempt to get them to work out a mutual single source of truth.  But that doesn’t exist.  There are two completely valid truths that the developers need to support.  How is this to be supported and honour the Single Responsibility Principle?  The solution is to duplicate the data access layer and let each stakeholder control their own copy. The Single Source of Truth and Single Responsibility Principles are very closely related.  SST tells you when to remove duplication; SRP tells you when to introduce it.  They may seem to be fighting each other, but really they are not.  The key is to clearly identify the different responsibilities (or sources of truth) over a system.  Sometimes there is a single person with that responsibility, other times there are many.  This can be especially difficult if the same person has dual responsibilities.  They might not even realize they are wearing multiple hats. In my opinion Single Source of Truth should be listed as the second rule of simple design with Express Intent at number three.  Investigation of the DRY code smell should yield to the proper application SST, without violating SRP.  When necessary leave duplication in the system and let the class names express the different people that are responsible for controlling them.  Knowing all the people with responsibilities over a system is the higher priority because you’ll need to know this before you can express it.  Although it may be a code smell when there is duplication in the code, it does not necessarily mean that the coder has chosen to be expressive over DRY or that the code is bad.

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  • Do any languages other than haskell/agda have a hindley-milner type system and type classes?

    - by Jimmy Hoffa
    In pondering what gives Haskell such a layer of mental pain in becoming proficient the main thing I can think of are the Monads, Applicatives, Functors, and gaining an intuition to know how a list or maybe will behave in regards to sequence or alternate or bind etc. But why haven't other languages presented these same concepts given the usefulness of monads/applicatives/etc? It occurs to me, type classes are the key, so the question is: Have any languages other than Haskell/Agda actually implemented type classes in the same or similar way?

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  • What am I allowed to do programmatically with pictures that have a Creative Commons "don't modify" license

    - by nist
    I'm working on a project that uses some icons that are under a Creative Commons license (ND) that forbids modification of the picture. What can I do with this icons as a programmer? Can I modify the looks of the image in the program as long as I don't change anything in the file that contains the icon? Have I modified the image if I put a colored transparent layer over it so the color of the icon changes?

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  • using sp_addrolemember

    - by Derek Dieter
    To add a user or group to a role, you need to use sp_addrolemember. This procedure is easy to use as it only accepts two parameters, the role name, and the username (or group). Roles are utilized in order to provide a layer of abstraction from permissions from being applied directly to users. While [...]

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  • Move Data into the grid for scalable, predictable response times

    - by JuergenKress
    CloudTran is pleased to introduce the availability of the CloudTran Transaction and Persistence Manager for creating scalable, reliable data services on the Oracle Coherence In-Memory Data Grid (IMDG). Use of IMDG architectures has been key to handling today’s web-scale loads because it eliminates database latency by storing important and frequently access data in memory instead of on disk. The CloudTran product lets developers easily use an IMDG for full ACID-compliant transactions without having to be concerned about the location or spread of data. The system has its own implementation of fast, scalable distributed transactions that does NOT depend on XA protocols but still guarantees all ACID properties. Plus, CloudTran asynchronously replicates data going into the IMDG to back-end datastores and back-up data centers, again ensuring ACID properties. CloudTran can be accessed through Java Persistence API (JPA via TopLink Grid) and now, through a new Low-Level API, or LLAPI. This is ideal for use in SOA applications that need data reliability, high availability, performance, and scalability. It is still in its limited beta release, the LLAPI gives developers the ability to use standard put/remove logic available in Coherence and then wrap logic with simple Spring annotations or XML+AspectJ to start transactions. An important feature of LLAPI is the ability to join transactions. This is a common outcome for SOA applications that need to reduce network traffic by aggregating data into single cache entries and then doing SOA service processing in the node holding the data. This results in the need to orchestrate transaction processing across multiple service calls. CloudTran has the capability to handle these “multi-client” transactions at speed with no loss in ACID properties. Developing software around an IMDG like Oracle Coherence is an important choice for today’s web-scale applications and services. But this introduces new architectural considerations to maintain scalability in light of increased network loads and data movement. Without using CloudTran, developers are faced with an incredibly difficult task to ensure data reliability, availability, performance, and scalability when working with an IMDG. Working with highly distributed data that is entirely volatile while stored in memory presents numerous edge cases where failures can result in data loss. The CloudTran product takes care of all of this, leaving developers with the confidence and peace of mind that all data is processed correctly. For those interested in evaluating the CloudTran product and IMDGs, take a look at this link for more information: http://www.CloudTran.com/downloadAPI.ph , or send your questions to [email protected]. 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: CloudTran,data grid,M,SOA Community,Oracle SOA,Oracle BPM,BPM,Community,OPN,Jürgen Kress

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  • Displaying performance data per engine subsystem

    - by liortal
    Our game (Android based) traces how long it takes to do the world logic updates, and how long it takes to a render a frame to the device screen. These traces are collected every frame, and displayed at a constant interval (currently every 1 second). I've seen games where on-screen data of various engine subsystems is displayed, with the time they consume (either in text) or as horizontal colored bars. I am wondering how to implement such a feature?

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  • How do you manage extensibility in your multi-tenant systems?

    - by Brian MacKay
    I've got a few big web based multi-tenant products now, and very soon I can see that there will be a lot of customizations that are tenant specific. An extra field here or there, maybe an extra page or some extra logic in the middle of a workflow - that sort of thing. Some of these customizations can be rolled into the core product, and that's great. Some of them are highly specific and would get in everyone else's way. I have a few ideas in mind for managing this, but none of them seem to scale well. The obvious solution is to introduce a ton of client-level settings, allowing various 'features' to be enabled on per-client basis. The downside with that, of course, is massive complexity and clutter. You could introduce a truly huge number of settings, and over time various types of logic (presentation, business) could get way out of hand. Then there's the problem of client-specific fields, which begs for something cleaner than just adding a bunch of nullable fields to the existing tables. So what are people doing to manage this? Force.com seems to be the master of extensibility; obviously they've created a platform from the ground up that is super extensible. You can add on to almost anything with their web-based UI. FogBugz did something similiar where they created a robust plugin model that, come to think of it, might have actually been inspired by Force. I know they spent a lot of time and money on it and if I'm not mistaken the intention was to actually use it internally for future product development. Sounds like the kind of thing I could be tempted to build but probably shouldn't. :) Is a massive investment in pluggable architecture the only way to go? How are you managing these problems, and what kind of results are you seeing? EDIT: It does look as though FogBugz handled the problem by building a fairly robust platform and then using that to put together their screens. To extend it you create a DLL containing classes that implement interfaces like ISearchScreenGridColumn, and that becomes a module. I'm sure it was tremendously expensive to build considering that they have a large of devs and they worked on it for months, plus their surface area is perhaps 5% of the size of my application. Right now I am seriously wondering if Force.com is the right way to handle this. And I am a hard core ASP.Net guy, so this is a strange position to find myself in.

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  • How do I import my first sprites?

    - by steven_desu
    Continuing from this question (new question - now unrelated) So I have a thorough background in programming already (algorithms, math, logic, graphing problems, etc.) however I've never attempted to code a game before. In fact, I've never had anything more than minimal input from a user during the execution of a program. Generally input was given from a file or passed through console, all necessary functions were performed, then the program terminated with an output. I decided to try and get in on the world of game development. From several posts I've seen around gamedev.stackexchange.com XNA seems to be a favorite, and it was recommended to me when I asked where to start. I've downloaded and installed Visual Studio 2010 along with the XNA Framework and now I can't seem to get moving in the right direction. I started out looking on Google for "xna game studio tutorial", "xna game development beginners", "my first xna game", etc. I found lots of crap. The official "Introduction to Game Studio 4.0" gave me this (plus my own train of thought happily pasted on top thanks to MSPaint): http://tinypic.com/r/2w1sgvq/7 The "Get Additional Help" link (my best guess, since there was no "Continue" or "Next" link) lead me to this page: http://tinypic.com/r/2qa0dgx/7 I tried every page. The forum was the only thing that seemed helpful, however searching for "beginner", "newbie", "getting started", "first project", and similar on the forums turned up many threads with specific questions that are a bit above my level ("beginner to collision detection", for instance) Disappointed I returned to the XNA Game Studio home page. Surely their own website would have some introduction, tutorial, or at least a useful link to a community. EVERYTHING on their website was about coding Windows Phone 7.... Everything. http://tinypic.com/r/10eit8i/7 http://tinypic.com/r/120m9gl/7 Giving up on any official documentation after a while, I went back to Google. I managed to locate www.xnadevelopment.com. The website is built around XNA Game Studio 3.0, but how different can 3.0 be from 4.0?.... Apparently different enough. http://tinypic.com/r/5d8mk9/7 http://tinypic.com/r/25hflli/7 Figuring that this was the correct folder, I right-clicked.... http://tinypic.com/r/24o94yu/7 Hmm... maybe by "Add Content Reference" they mean "Add a reference to an existing file (content)"? Let's try it (after all- it's my only option) http://tinypic.com/r/2417eqt/7 At this point I gave up. I'm back. My original goal in my last question was to create a keyboard-navigable 3D world (no physics necessary, no logic or real game necessary). After my recent failures my goal has been revised. I want to display an image on the screen. Hopefully in time I'll be able to move it with the keyboard.

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  • C++ Accelerated Massive Parallelism

    - by Daniel Moth
    At AMD's Fusion conference Herb Sutter announced in his keynote session a technology that our team has been working on that we call C++ Accelerated Massive Parallelism (C++ AMP) and during the keynote I showed a brief demo of an app built with our technology. After the keynote, I go deeper into the technology in my breakout session. If you read both those abstracts, you'll get some information about what C++ AMP is, without being too explicit since we published the abstracts before the technology was announced. You can find the official online announcement at Soma's blog post. Here, I just wanted to capture the key points about C++ AMP that can serve as an introduction and an FAQ. So, in no particular order… C++ AMP lowers the barrier to entry for heterogeneous hardware programmability and brings performance to the mainstream, without sacrificing developer productivity or solution portability. is designed not only to help you address today's massively parallel hardware (i.e. GPUs and APUs), but it also future proofs your code investments with a forward looking design. is part of Visual C++. You don't need to use a different compiler or learn different syntax. is modern C++. Not C or some other derivative. is integrated and supported fully in Visual Studio vNext. Editing, building, debugging, profiling and all the other goodness of Visual Studio work well with C++ AMP. provides an STL-like library as part of the existing concurrency namespace and delivered in the new amp.h header file. makes it extremely easy to work with large multi-dimensional data on heterogeneous hardware; in a manner that exposes parallelization. introduces only one core C++ language extension. builds on DirectX (and DirectCompute in particular) which offers a great hardware abstraction layer that is ubiquitous and reliable. The architecture is such, that this point can be thought of as an implementation detail that does not surface to the API layer. Stay tuned on my blog for more over the coming months where I will switch from just talking about C++ AMP to showing you how to use the API with code examples… Comments about this post welcome at the original blog.

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