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  • Should each app have its own database, or should small apps be merged into one?

    - by King
    We have a bunch of small to medium sized apps, each of which has its own database (MSSQL Server). There was a suggestion that we consoldate the 'related' databases into a smaller set amount of larger databases. They don't particularly share a lot of data, they would just be under a similar business group. For example, using a 'Finance' DB to hold the tables and procedures for finance apps. Would it be appropriate to use a different schema for each app? E.g. App1.SomeTable App1.SomeOtherTable AppTwo.SomeTable What are the pros and cons of this approach? What should I watch out for? Thanks

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  • Single database, multiple system dependency

    - by davenewza
    Consider an environment where we have a single, core database, with many separate systems using this one database. This leads to all of these systems have a common dependency, which ultimately introduces coupling between them. This means that we cannot always evolve systems independently of each other. Structural changes to the database (even if only intended for one, particular system), requires a full sweep test of ALL systems, and may require that other systems be 'patched' and subsequently released. This is especially tricky when you want to have separate teams working on different projects. What is a good 'pattern' to help in avoiding such coupling? I would imagine that a database should be exclusively depended on by one system. If other systems require data for whatever reason, they should request such from an API service of some kind. A drawback of this approach which comes to mind is performance: routing data between high-throughput systems through service calls is much slower than through a database connection.

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  • My boss has a different idea of a website's UX [migrated]

    - by NicoJuicy
    Let me explain the situation. I started transforming a "old (.Net 2.0)" Application into a webapplication. Problem here is, that no-one here is really acquainted with the UX of a website (Simple, efficient). Eventhough, i still have to regard that the website can be tailored to a customer needs through parameters (yeah, i know :s ) For example: I wanted to have a layout similar to invoicemachine (= as simple as possible). -- He wants a Ribbon toolbar. Going to a supplier gives the list of supplier -- He wants to display the "Create Supplier" screen where you can use the wildcards in a certain textbox, to search for a specific Supplier and then give the list of the suppliers. Also, i need 4 search/filter mechanisms: people can search per field with wildmarks can filter the suppliers search a keyword through all the data of a supplier filter the "list Suppliers" page by the first letter of the name. LIST Suppliers | A | D | Z Adam Wrincle ADD |EDIT |Delete Damzel InDistress ADD |EDIT |Delete Zorro ADD |EDIT |Delete I can't seem to get through to him, that the UX of a website needs to be differently than a Windows Application. If he wants to bring all the logic of the windows app into a website, why letting me build a website then? Stick to the old solution. Am i mistaking so hard or how could i convince / show him that an online-solution is something different than the offline solution. He already "saw" online solutions of other applications to get an idea, but if i suggest something he won't listen (if it's GUI / UX related, that is).

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  • How to create a fountain in UDK

    - by user36425
    I'm trying to make a fountain in my level in UDK, I made the base of the fountain by using a Cylinder build and now I'm trying to put water in it. I went to use the fluidSurfaceActor but I notice that this is square but my fountain is a cylinder. Is there a way that I can change the shape of the fluidSurfaceActor to fit the builder brush shape or is there another way to do this? Or is it hopeless and I have to make my fountain into a cube? Here is a link/picture to the screenprint of what I'm talking about:

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  • How do I choose the scaling factor of a 3D game world?

    - by concept3d
    I am making a 3D tank game prototype with some physics simulation, am using C++. One of the decisions I need to make is the scale of the game world in relation to reality. For example, I could consider 1 in-game unit of measurement to correspond to 1 meter in reality. This feels intuitive, but I feel like I might be missing something. I can think of the following as potential problems: 3D modelling program compatibility. (?) Numerical accuracy. (Does this matter?) Especially at large scales, how games like Battlefield have huge maps: How don't they lose numerical accuracy if they use 1:1 mapping with real world scale, since floating point representation tend to lose more precision with larger numbers (e.g. with ray casting, physics simulation)? Gameplay. I don't want the movement of units to feel slow or fast while using almost real world values like -9.8 m/s^2 for gravity. (This might be subjective.) Is it ok to scale up/down imported assets or it's best fit with a world with its original scale? Rendering performance. Are large meshes with the same vertex count slower to render? I'm wondering if I should split this into multiple questions...

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  • Resources for popular domain models

    - by Songo
    I have come across many situations where I had to build a system for a library or a clinic or other popular domains. The thing is a domain model for a library was probably done 1000 times already with different level of details of course. Here is an example. Is there a popular website or community where one can find ready made domain models for popular systems? The whole purpose I'm trying to achieve is to quickly get a grasp of the domain I'm modeling and customize it to my needs. Re-inventing the wheel seems really absurd when the same system might have been modeled properly previously. Note I know Google might sound like the perfect source, but there is a repository out there that people can post there models, so that others can share them.

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  • Domain Models (PHP)

    - by Calum Bulmer
    I have been programming in PHP for several years and have, in the past, adopted methods of my own to handle data within my applications. I have built my own MVC, in the past, and have a reasonable understanding of OOP within php but I know my implementation needs some serious work. In the past I have used an is-a relationship between a model and a database table. I now know after doing some research that this is not really the best way forward. As far as I understand it I should create models that don't really care about the underlying database (or whatever storage mechanism is to be used) but only care about their actions and their data. From this I have established that I can create models of lets say for example a Person an this person object could have some Children (human children) that are also Person objects held in an array (with addPerson and removePerson methods, accepting a Person object). I could then create a PersonMapper that I could use to get a Person with a specific 'id', or to save a Person. This could then lookup the relationship data in a lookup table and create the associated child objects for the Person that has been requested (if there are any) and likewise save the data in the lookup table on the save command. This is now pushing the limits to my knowledge..... What if I wanted to model a building with different levels and different rooms within those levels? What if I wanted to place some items in those rooms? Would I create a class for building, level, room and item with the following structure. building can have 1 or many level objects held in an array level can have 1 or many room objects held in an array room can have 1 or many item objects held in an array and mappers for each class with higher level mappers using the child mappers to populate the arrays (either on request of the top level object or lazy load on request) This seems to tightly couple the different objects albeit in one direction (ie. a floor does not need to be in a building but a building can have levels) Is this the correct way to go about things? Within the view I am wanting to show a building with an option to select a level and then show the level with an option to select a room etc.. but I may also want to show a tree like structure of items in the building and what level and room they are in. I hope this makes sense. I am just struggling with the concept of nesting objects within each other when the general concept of oop seems to be to separate things. If someone can help it would be really useful. Many thanks

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  • How to manage own bots at the server?

    - by Nikolay Kuznetsov
    There is a game server and people can play in game rooms of 2, 3 or 4. When a client connects to server he can send a request specifying a number of people or range he wants to play with. One of this value is valid: {2-4, 2-3, 3-4, 2, 3, 4} So the server maintains 3 separate queues for game room with 2, 3 and 4 people. So we can denote queues as #2, #3 and #4. It work the following way. If a client sends request, 3-4, then two separate request are added to queues #3 and #4. If queue #3 now have 3 requests from different people then game room with 3 players is created, and all other requests from those players are removed from all queues. Right now not many people are online simultaneously, so they apply for a game wait for some time and quit because game does not start in a reasonable time. That's a simple bot for beginning has been developed. So there is a need to patch server code to run a bot, if some one requests a game, but humans are not online. Input: request from human {2-4, 2-3, 3-4, 2, 3, 4} Output: number of bots to run and time to wait for each before connecting, depending on queues state. The problem is that I don't know how to manage bots properly at the server? Example: #3 has 1 request and #4 has 1 request Request from user is {3,4} then server can add one bot to play game with 3 people or two bots to play game of 4. Example: #3 has 1 request and #4 has 2 requests Request from user is {3,4} then in each case just one bot is needed so game with 4 players is more preferrable.

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  • Do ORMs enable the creation of rich domain models?

    - by Augusto
    After using Hibernate on most of my projects for about 8 years, I've landed on a company that discourages its use and wants applications to only interact with the DB through stored procedures. After doing this for a couple of weeks, I haven't been able to create a rich domain model of the application I'm starting to build, and the application just looks like a (horrible) transactional script. Some of the issues I've found are: Cannot navigate object graph as the stored procedures just load the minimum amount of data, which means that sometimes we have similar objects with different fields. One example is: we have a stored procedure to retrieve all the data from a customer, and another to retrieve account information plus a few fields from the customer. Lots of the logic ends up in helper classes, so the code becomes more structured (with entities used as old C structs). More boring scaffolding code, as there's no framework that extracts result sets from a stored procedure and puts it in an entity. My questions are: has anyone been in a similar situation and didn't agree with the store procedure approch? what did you do? Is there an actual benefit of using stored procedures? appart from the silly point of "no one can issue a drop table". Is there a way to create a rich domain using stored procedures? I know that there's the posibility of using AOP to inject DAOs/Repositories into entities to be able to navigate the object graph. I don't like this option as it's very close to voodoo.

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  • What is the best way to render a 2d game map?

    - by Deukalion
    I know efficiency is key in game programming and I've had some experiences with rendering a "map" earlier but probably not in the best of ways. For a 2D TopDown game: (simply render the textures/tiles of the world, nothing else) Say, you have a map of 1000x1000 (tiles or whatever). If the tile isn't in the view of the camera, it shouldn't be rendered - it's that simple. No need to render a tile that won't be seen. But since you have 1000x1000 objects in your map, or perhaps less you probably don't want to loop through all 1000*1000 tiles just to see if they're suppose to be rendered or not. Question: What is the best way to implement this efficiency? So that it "quickly/quicker" can determine what tiles are suppose to be rendered? Also, I'm not building my game around tiles rendered with a SpriteBatch so there's no rectangles, the shapes can be different sizes and have multiple points, say a curved object of 10 points and a texture inside that shape; Question: How do you determine if this kind of objects is "inside" the View of the camera? It's easy with a 48x48 rectangle, just see if it X+Width or Y+Height is in the view of the camera. Different with multiple points. Simply put, how to manage the code and the data efficiently to not having to run through/loop through a million of objects at the same time.

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  • Java EE 8 update

    - by delabassee
    Planning for Java EE 8 is now well underway. As you know, a few weeks ago, we conducted a three part Java EE 8 Community Survey (you can find the final summary here). The data gathered have been very influential for the next steps. You can now expect over the coming weeks and months to see updates on the various specifications that compose the Java EE platform. Some Specification Leads are busy gathering additional feedback regarding what they should focus their efforts on (e.g. CDI 2 survey). Other Specification Leads have already publicly exposed what they think should be one of the focus for the evolution of the specification they lead.  For example, adding Server-Senet Events (SSE) support in JAX-RS is being discussed here and adding MVC support is being discussed here. Please remember that the fact we are now discussing any feature does not insure that it will be included in the proposal, nor in any particular update to Java EE. We can expect additional enhancements, changes and evolutions as we get closer to the finalisation of the different specifications... and there is still a long way to go with these specification proposals! Linda DeMichiel, Java EE Co-Specification Lead, has recently posted a draft proposal for the Java EE 8 Platform specification. Linda's goal is to recruit people and companies supporting this proposal before submitting it to the JCP.  This draft proposal is very interesting reading as it contains relevant information on the plans for Java EE 8 such as : The themes: Support for the latest web standards (eg. HTTP 2.0)  Continue to work on ease of development Improve the infrastructure for cloud support Alignment with Java SE 8 New JSRs to be added to the platform: J-Cache Java API for JSON Binding Java Configuration Plans for the Web Profile Plans on technologies to prune in Java EE 8, ... So if you haven't done it yet, I really encourage you to read the Java EE 8 draft proposal! Our goal for the Java EE 8 specification is for it to be finalized in the second half of 2016. It is important to note that we are in the early days of Java EE 8 and at this stage everything (themes, content, timing, etc.) is preliminary. Everything still needs to be discussed, challenged and agreed within the different Java Community Process (JCP) Experts Groups (EGs). Some EGs that still need to be formed! It could also means that the roadmap will have to be adjusted to follow the progress being made in the different EGs. This is also a good occasion to remind you that participation within those upcoming JCP Experts Groups is encouraged. Contributing in an EG is an effective lever to influence what Java EE 8 will become! Finally, as things get more concrete, we will share details on how to engage in the different Java EE 8 related Adopt-a-JSR initiatives, another way to contribute. You can also read other posts related to Java EE 8, here at The Aquarium blog. Just look for articles with the 'javaee8' tag.

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  • Java - What methods to put in an interface and what to keep out

    - by lewicki
    I'm designing a file handler interface: public interface FileHandler { public void openFileHandler(String fileName); public void closeFileHandler(); public String readLine(); public String [] parseLine(String line); public String [] checkLine(String line[]); public void incrementLineCount(); public void incrementLineSuccessCount(); public void incrementLineErrorCount(); public int getLineCount(); public int getLineSuccessCount(); public int getLineErrorCount(); } It is soon apparent to me that these methods can't be made private. I don't want incrementLineCount to be public. What is proper way to design an interface like this?

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  • Strategies for invoking subclass methods on generic objects

    - by Brad Patton
    I've run into this issue in a number of places and have solved it a bunch of different ways but looking for other solutions or opinions on how to address. The scenario is when you have a collection of objects all based off of the same superclass but you want to perform certain actions based only on instances of some of the subclasses. One contrived example of this might be an HTML document made up of elements. You could have a superclass named HTMLELement and subclasses of Headings, Paragraphs, Images, Comments, etc. To invoke a common action across all of the objects you declare a virtual method in the superclass and specific implementations in all of the subclasses. So to render the document you could loop all of the different objects in the document and call a common Render() method on each instance. It's the case where again using the same generic objects in the collection I want to perform different actions for instances of specific subclass (or set of subclasses). For example (an remember this is just an example) when iterating over the collection, elements with external links need to be downloaded (e.g. JS, CSS, images) and some might require additional parsing (JS, CSS). What's the best way to handle those special cases. Some of the strategies I've used or seen used include: Virtual methods in the base class. So in the base class you have a virtual LoadExternalContent() method that does nothing and then override it in the specific subclasses that need to implement it. The benefit being that in the calling code there is no object testing you send the same message to each object and let most of them ignore it. Two downsides that I can think of. First it can make the base class very cluttered with methods that have nothing to do with most of the hierarchy. Second it assumes all of the work can be done in the called method and doesn't handle the case where there might be additional context specific actions in the calling code (i.e. you want to do something in the UI and not the model). Have methods on the class to uniquely identify the objects. This could include methods like ClassName() which return a string with the class name or other return values like enums or booleans (IsImage()). The benefit is that the calling code can use if or switch statements to filter objects to perform class specific actions. The downside is that for every new class you need to implement these methods and can look cluttered. Also performance could be less than some of the other options. Use language features to identify objects. This includes reflection and language operators to identify the objects. For example in C# there is the is operator that returns true if the instance matches the specified class. The benefit is no additional code to implement in your object hierarchy. The only downside seems to be the lack of using something like a switch statement and the fact that your calling code is a little more cluttered. Are there other strategies I am missing? Thoughts on best approaches?

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  • DDD and validation of aggregate root

    - by Mik378
    Suppose an aggregate root : MailConfiguration (wrapping an AddressPart object). The AddressPart object is a simple immutable value object with some fields like senderAdress, recipentAddress (to make example simple). As being an invariant object, AddressPart should logically wrap its own Validator (by the way of external a kind of AddressValidator for respecting Single Responsibility Principle) I read some articles that claimed an aggregateRoot must validate its 'children'. However, if we follow this principle, one could create an AddressPart with an uncohesive/invalid state. What are your opinion? Should I move the collaborator AddressValidator(used in constructor so in order to validate immediately the cohesion of an AddressPart) from AddressPart and assign it to aggregateRoot (MailConfiguration) ?

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  • How can Java be improved so that it no longer needs to perform type erasure? [closed]

    - by user63904
    The official Java tutorial on generics explains type erasure and why it was added to the compiler: When a generic type is instantiated, the compiler translates those types by a technique called type erasure — a process where the compiler removes all information related to type parameters and type arguments within a class or method. Type erasure enables Java applications that use generics to maintain binary compatibility with Java libraries and applications that were created before generics. This most likely was a pragmatic approach, or perhaps the least painful one. However, now that generics is widely supported across the industry, what can be done in order for us to not need type erasure? Is it feasible with out needing to break backwards compatibility, or if it is feasible, is it practical? Has the last the last statement in the quote above become self referential? That is: "type erasure enables Java applications that use generics to maintain binary compatibility with Java libraries and applications that were created with Java versions that perform type erasure."

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  • Looking for games in environments similar to a pinball table

    - by chaosTechnician
    I'm on a team of students working on a third-person adventure game that takes place inside a pinball machine (like, small scale, on the surface, avoiding pinballs, etc). One of my responsibilities on the project is to find games that are similar to this concept in appearance and/or gameplay for reference. So, does anyone know of games (other than pinball) that takes place in a pinball-like environment? Or, adventure games that take place in small, cramped environments with multiple paths around the world? Or games in which the player is often bombarded with balls (or other similar unintelligent obstacles)? Or games that take place on a small scale?

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  • Liskov substitution principle with abstract parent class

    - by Songo
    Does Liskov substitution principle apply to inheritance hierarchies where the parent is an abstract class the same way if the parent is a concrete class? The Wikipedia page list several conditions that have to be met before a hierarchy is deemed to be correct. However, I have read in a blog post that one way to make things easier to conform to LSP is to use abstract parent instead of a concrete class. How does the choice of the parent type (abstract vs concrete) impacts the LSP? Is it better to have an abstract base class whenever possible?

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  • I've been told that Exceptions should only be used in exceptional cases. How do I know if my case is exceptional?

    - by tieTYT
    My specific case here is that the user can pass in a string into the application, the application parses it and assigns it to structured objects. Sometimes the user may type in something invalid. For example, their input may describe a person but they may say their age is "apple". Correct behavior in that case is roll back the transaction and to tell the user an error occurred and they'll have to try again. There may be a requirement to report on every error we can find in the input, not just the first. In this case, I argued we should throw an exception. He disagreed, saying, "Exceptions should be exceptional: It's expected that the user may input invalid data, so this isn't an exceptional case" I didn't really know how to argue that point, because by definition of the word, he seems to be right. But, it's my understanding that this is why Exceptions were invented in the first place. It used to be you had to inspect the result to see if an error occurred. If you failed to check, bad things could happen without you noticing. Without exceptions every level of the stack needs to check the result of the methods they call and if a programmer forgets to check in one of these levels, the code could accidentally proceed and save invalid data (for example). Seems more error prone that way. Anyway, feel free to correct anything I've said here. My main question is if someone says Exceptions should be exceptional, how do I know if my case is exceptional?

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  • When module calling gets ugly

    - by Pete
    Has this ever happened to you? You've got a suite of well designed, single-responsibility modules, covered by unit tests. In any higher-level function you code, you are (95% of the code) simply taking output from one module and passing it as input to the next. Then, you notice this higher-level function has turned into a 100+ line script with multiple responsibilities. Here is the problem. It is difficult (impossible) to test that script. At least, it seems so. Do you agree? In my current project, all of the bugs came from this script. Further detail: each script represents a unique solution, or algorithm, formed by using different modules in different ways. Question: how can you remedy this situation? Knee-jerk answer: break the script up into single-responsibility modules. Comment on knee-jerk answer: it already is! Best answer I can come up with so far: create higher-level connector objects which "wire" modules together in particular ways (take output from one module, feed it as input to another module). Thus if our script was: FooInput fooIn = new FooInput(1, 2); FooOutput fooOutput = fooModule(fooIn); Double runtimevalue = getsomething(fooOutput.whatever); BarInput barIn = new BarInput( runtimevalue, fooOutput.someOtherValue); BarOutput barOut = barModule(BarIn); It would become with a connector: FooBarConnectionAlgo fooBarConnector = new fooBarConnector(fooModule, barModule); FooInput fooIn = new FooInput(1, 2); BarOutput barOut = fooBarConnector(fooIn); So the advantage is, besides hiding some code and making things clearer, we can test FooBarConnectionAlgo. I'm sure this situation comes up a lot. What do you do?

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  • Enemy Spawning method in a Top-Down Shooter

    - by Chris Waters
    I'm working on a top-down shooter akin to DoDonPachi, Ikaruga, etc. The camera movement through the world is handled automatically with the player able to move inside of the camera's visible region. Along the way, enemies are scripted to spawn at particular points along the path. While this sounds straightforward, I could see two ways to define these points: Camera's position: 'trigger' spawning as the camera passes by the points Time along path: "30 seconds in, spawn 2 enemies" In both cases, the camera-relative positions would be defined as well as the behavior of the enemy. The way I see it, the way you define these points will directly affect how the 'level editor', or what have you, will work. Would there be any benefits of one approach over the other?

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  • Best approach for saving highlighted areas on geographical map.

    - by Mohsen
    I am designing an application that allow users to highlight areas of a geographical map using a tool that is like brush or a pen. The tool basically draw a circle with a single click and continue drawing those circles with move move. Here is an example of drawing made by moving the tool. It is pretty much same as Microsoft Paint. Regardless of programming language what is best approach (most inexpensive approach) for saving this kind of data?

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  • How to make an Actor follow my finger

    - by user48352
    I'm back with another question that may be really simple. I've a texture drawn on my spritebatch and I'm making it move up or down (y-axis only) with Libgdx's Input Handler: touchDown and touchUp. @Override public boolean touchDown(int screenX, int screenY, int pointer, int button) { myWhale.touchDownY = screenY; myWhale.isTouched = true; return true; } @Override public boolean touchUp(int screenX, int screenY, int pointer, int button) { myWhale.isTouched = false; return false; } myWhale is an object from Whale Class where I move my texture position: public void update(float delta) { this.delta = delta; if(isTouched){ dragWhale(); } } public void dragWhale() { if(Gdx.input.getY(0) - touchDownY < 0){ if(Gdx.input.getY(0)<position.y+height/2){ position.y = position.y - velocidad*delta; } } else{ if(Gdx.input.getY(0)>position.y+height/2){ position.y = position.y + velocidad*delta; } } } So the object moves to the center of the position where the person is pressing his/her finger and most of the time it works fine but the object seems to take about half a second to move up or down and sometimes when I press my finger it wont move. Maybe there's another simplier way to do this. I'd highly appreciate if someone points me on the right direction.

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  • DDD / Layers and legacy systems

    - by CSM
    I have to refactor a complex C# app (many dialogs, mixed logic and so on). There is a part managing the communication with special hardware equipments (sending commands and receive data via asynchronous c# callbacks). The code is "spaghetti" with mixed UI/Logic/Communication/etc and my task is to split the layers in a DDD sense. So, to which layer belongs a callback driver routine? The callbacks are creating "bubbles" in the system, up to the UI layer and because of this I cannot enforce the essential principle that any element of a layer depends only on other elements in the same layer or on elements of the layers "beneath" it. Thank you in advance.

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