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  • Java game object pool management

    - by Kenneth Bray
    Currently I am using arrays to handle all of my game objects in the game I am making, and I know how terrible this is for performance. My question is what is the best way to handle game objects and not hurt performance? Here is how I am creating an array and then looping through it to update the objects in the array: public static ArrayList<VboCube> game_objects = new ArrayList<VboCube>(); /* add objects to the game */ while (!Display.isCloseRequested() && !Keyboard.isKeyDown(Keyboard.KEY_ESCAPE)) { for (int i = 0; i < game_objects.size(); i++){ // draw the object game_objects.get(i).Draw(); game_objects.get(i).Update(); //world.updatePhysics(); } } I am not looking for someone to write me code for asset or object management, just point me into a better direction to get better performance. I appreciate the help you guys have provided me in the past, and I dont think I would be as far along with my project without the support on stack exchange!

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  • OOP concept: is it possible to update the class of an instantiated object?

    - by Federico
    I am trying to write a simple program that should allow a user to save and display sets of heterogeneous, but somehow related data. For clarity sake, I will use a representative example of vehicles. The program flow is like this: The program creates a Garage object, which is basically a class that can contain a list of vehicles objects Then the users creates Vehicles objects, these Vehicles each have a property, lets say License Plate Nr. Once created, the Vehicle object get added to a list within the Garage object --Later on--, the user can specify that a given Vehicle object is in fact a Car object or a Truck object (thus giving access to some specific attributes such as Number of seats for the Car, or Cargo weight for the truck) At first sight, this might look like an OOP textbook question involving a base class and inheritance, but the problem is more subtle because at the object creation time (and until the user decides to give more info), the computer doesn't know the exact Vehicle type. Hence my question: how would you proceed to implement this program flow? Is OOP the way to go? Just to give an initial answer, here is what I've came up until now. There is only one Vehicle class and the various properties/values are handled by the main program (not the class) through a dictionary. However, I'm pretty sure that there must be a more elegant solution (I'm developing using VB.net): Public Class Garage Public GarageAdress As String Private _ListGarageVehicles As New List(Of Vehicles) Public Sub AddVehicle(Vehicle As Vehicles) _ListGarageVehicles.Add(Vehicle) End Sub End Class Public Class Vehicles Public LicensePlateNumber As String Public Enum VehicleTypes Generic = 0 Car = 1 Truck = 2 End Enum Public VehicleType As VehicleTypes Public DictVehicleProperties As New Dictionary(Of String, String) End Class NOTE that in the example above the public/private modifiers do not necessarily reflect the original code

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  • Object Oriented Programming in AS3

    - by Jordan
    I'm building a game in as3 that has balls moving and bouncing off the walls. When the user clicks an explosion appears and any ball that hits that explosion explodes too. Any ball that then hits that explosion explodes and so on. My question is what would be the best class structure for the balls. I have a level system to control levels and such and I've already come up with working ways to code the balls. Here's what I've done. My first attempt was to create a class for Movement, Bounce, Explosion and finally Orb. These all extended each other in the order I just named them. I got it working but having Bounce extend Movement and Explosion extend Bounce, it just doesn't seem very object oriented because what if I wanted to add a box class that didn't move, but did explode? I would need a separate class for that explosion. My second attempt was to create Movement, Bounce and Explosion without extending anything. Instead I passed in a reference to the Orb class to each. Then the class stores that reference and does what it needs to do based on events that are dispatched by the Orb such as update, which was broadcast from Orb every enter frame. This would drive the movement and bounce and also the explosion when the time came. This attempt worked as well but it just doesn't seem right. I've also thought about using Interfaces but because they are more of an outline for classes, I feel like code reuse goes out the window as each class would need its own code for a specific task even if that task is exactly the same. I feel as if I'm searching for some form of multiple inheritance for classes that as3 does not support. Can someone explain to me a better way of doing what I'm attempting to do? Am I being to "Object Oriented" by having classed for Movement, Bounce, Explosion and Orb? Are Interfaces the way to go? Any feedback is appreciated!

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  • Converting to a column oriented array in Java

    - by halfwarp
    Although I have Java in the title, this could be for any OO language. I'd like to know a few new ideas to improve the performance of something I'm trying to do. I have a method that is constantly receiving an Object[] array. I need to split the Objects in this array through multiple arrays (List or something), so that I have an independent list for each column of all arrays the method receives. Example: List<List<Object>> column-oriented = new ArrayList<ArrayList<Object>>(); public void newObject(Object[] obj) { for(int i = 0; i < obj.length; i++) { column-oriented.get(i).add(obj[i]); } } Note: For simplicity I've omitted the initialization of objects and stuff. The code I've shown above is slow of course. I've already tried a few other things, but would like to hear some new ideas. How would you do this knowing it's very performance sensitive?

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  • Javascript Reference Outer Object From Inner Object

    - by Akidi
    Okay, I see a few references given for Java, but not javascript ( which hopefully you know is completely different ). So here's the code specific : function Sandbox() { var args = Array.prototype.slice.call(arguments) , callback = args.pop() , modules = (args[0] && typeof args[0] === 'string' ? args : args[0]) , i; if (!(this instanceof Sandbox)) { return new Sandbox(modules, callback); } if (!modules || modules[0] === '*') { modules = []; for (i in Sandbox.modules) { if (Sandbox.modules.hasOwnProperty(i)) { modules.push(i); } } } for (i = 0; i < modules.length; i++) { Sandbox.modules[modules[i]](this); } this.core = { 'exp': { 'classParser': function (name) { return (new RegExp("(^| )" + name + "( |$)")); }, 'getParser': /^(#|\.)?([\w\-]+)$/ }, 'typeOf': typeOf, 'hasOwnProperty': function (obj, prop) { return obj.hasOwnProperty(prop); }, 'forEach': function (arr, fn, scope) { scope = scope || config.win; for (var i = 0, j = arr.length; i < j; i++) { fn.call(scope, arr[i], i, arr); } } }; this.config = { 'win' : win, 'doc' : doc }; callback(this); } How do I access this.config.win from within this.core.forEach? Or is this not possible?

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  • Column-oriented DBMS and JOIN operations

    - by André
    From some of the research I've done on NoSQL, column-oriented databases (like HBase or Cassandra) seem to solve the problem of costly JOIN operations, but I don't get how this approach solves this problem. Can anyone explain it to me and/or link me to interesting documentation regarding this area? Thanks

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  • How to create a link to Nintex Start Workflow Page in the document set home page

    - by ybbest
    In this blog post, I’d like to show you how to create a link to start Nintex Workflow Page in the document set home page. 1. Firstly, you need to upload the latest version of jQuery to the style library of your team site. 2. Then, upload a text file to the style library for writing your own html and JavaScript 3. In the document set home page, insert a new content editor web part and link the text file you just upload. 4. Update the text file with the following content, you can download this file here. <script type="text/javascript" src="/Style%20Library/jquery-1.9.0.min.js"></script> <script type="text/javascript" src="/_layouts/sp.js"></script> <script type="text/javascript"> $(document).ready(function() { listItemId=getParameterByName("ID"); setTheWorkflowLink("YBBESTDocumentLibrary"); }); function buildWorkflowLink(webRelativeUrl,listId,itemId) { var workflowLink =webRelativeUrl+"_layouts/NintexWorkflow/StartWorkflow.aspx?list="+listId+"&ID="+itemId+"&WorkflowName=Start Approval"; return workflowLink; } function getParameterByName(name) { name = name.replace(/[\[]/, "\\\[").replace(/[\]]/, "\\\]"); var regexS = "[\\?&]" + name + "=([^&#]*)"; var regex = new RegExp(regexS); var results = regex.exec(window.location.search); if(results == null){ return ""; } else{ return decodeURIComponent(results[1].replace(/\+/g, " ")); } } function setTheWorkflowLink(listName) { var SPContext = new SP.ClientContext.get_current(); web = SPContext.get_web(); list = web.get_lists().getByTitle(listName); SPContext.load(web,"ServerRelativeUrl"); SPContext.load(list, 'Title', 'Id'); SPContext.executeQueryAsync(setTheWorkflowLink_Success, setTheWorkflowLink_Fail); } function setTheWorkflowLink_Success(sender, args) { var listId = list.get_id(); var listTitle = list.get_title(); var webRelativeUrl = web.get_serverRelativeUrl(); var startWorkflowLink=buildWorkflowLink(webRelativeUrl,listId,listItemId) $("a#submitLink").attr('href',startWorkflowLink); } function setTheWorkflowLink_Fail(sender, args) { alert("There is a problem setting up the submit exam approval link"); } </script> <a href="" target="_blank" id="submitLink"><span style="font-size:14pt">Start the approval process.</span></a> 5. Save your changes and go to the document set Item, you will see the link is on the home page now. Notes: 1. You can create a link to start the workflow using the following build dynamic string configuration: {Common:WebUrl}/_layouts/NintexWorkflow/StartWorkflow.aspx?list={Common:ListID}&ID={ItemProperty:ID}&WorkflowName=workflowname. With this link you will still need to click the start button, this is standard SharePoint behaviour and cannot be altered. References: http://connect.nintex.com/forums/27143/ShowThread.aspx How to use html and JavaScript in Content Editor web part in SharePoint2010

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  • Explanation of the definition of interface inheritance as described in GoF book

    - by Geek
    I am reading the first chapter of the Gof book. Section 1.6 discusses about class vs interface inheritance: Class versus Interface Inheritance It's important to understand the difference between an object's class and its type. An object's class defines how the object is implemented.The class defines the object's internal state and the implementation of its operations.In contrast,an object's type only refers to its interface--the set of requests on which it can respond. An object can have many types, and objects of different classes can have the same type. Of course, there's a close relationship between class and type. Because a class defines the operations an object can perform, it also defines the object's type . When we say that an object is an instance of a class, we imply that the object supports the interface defined by the class. Languages like c++ and Eiffel use classes to specify both an object's type and its implementation. Smalltalk programs do not declare the types of variables; consequently,the compiler does not check that the types of objects assigned to a variable are subtypes of the variable's type. Sending a message requires checking that the class of the receiver implements the message, but it doesn't require checking that the receiver is an instance of a particular class. It's also important to understand the difference between class inheritance and interface inheritance (or subtyping). Class inheritance defines an object's implementation in terms of another object's implementation. In short, it's a mechanism for code and representation sharing. In contrast,interface inheritance(or subtyping) describes when an object can be used in place of another. I am familiar with the Java and JavaScript programming language and not really familiar with either C++ or Smalltalk or Eiffel as mentioned here. So I am trying to map the concepts discussed here to Java's way of doing classes, inheritance and interfaces. This is how I think of of these concepts in Java: In Java a class is always a blueprint for the objects it produces and what interface(as in "set of all possible requests that the object can respond to") an object of that class possess is defined during compilation stage only because the class of the object would have implemented those interfaces. The requests that an object of that class can respond to is the set of all the methods that are in the class(including those implemented for the interfaces that this class implements). My specific questions are: Am I right in saying that Java's way is more similar to C++ as described in the third paragraph. I do not understand what is meant by interface inheritance in the last paragraph. In Java interface inheritance is one interface extending from another interface. But I think the word interface has some other overloaded meaning here. Can some one provide an example in Java of what is meant by interface inheritance here so that I understand it better?

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  • Child object free movement on Parent object

    - by The415
    Just to be straightforward, I am completely new to many aspects of coding and am searching for different specs and guidelines to aid me on my journey to crafting a wonderful game in Epic Games' Unreal Engine 4. Okay, I know upon viewing this, some may have little to no clue what I mean, so I'll put it like this to explain what I mean : Imagine a third person game with a simple model of a character. Now, say I have an object as a torso of a character in a game. Now Say I have an object as a head of the character. How could I keep the head as a child of the torso, but at the same time, allow it to move with the camera angle.

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  • Using Bullet physics engine to find the moment of object contact before penetration

    - by MooMoo
    I would like to use Bullet Physics engine to simulate the objects in 3D world. One of the objects in the world will move using the position from 3D mouse control. I will call it "Mouse Object" and any object in the world as "Object A" I define the time before "mouse object" and "Object A" collide as t-1 The time "mouse object" penetrate "Object A" as t Now there is a problem about rendering the scene because when I move the mouse very fast, "Mouse object" will reside in "Object A" before "Object A" start to move. I would like the "Mouse Object" to stop right away attach to the "Object A". Also If the "Object A" move, the "Mouse object" should move following (attach) the "Object A" without stop at the first collision take place. This is what i did I find the position of the "Mouse Object" at time t-1 and time t. I will name it as pos(t-1) and pos(t) The contact time will be sometime between t-1 to t, which the time of contact I name it as t_contact, therefore the contact position (without penetration) between "Mouse object" and "Object A" will be pos(t_contact) then I create multiple "Mouse object"s using this equation pos[n] = pos(t-1) * C * ( pos(t) - pos(t-1) ) where 0 <= C <= 1 if I choose C = 0.1, 0.2, 0.3,0.4..... 1.0, I will get pos[n] for 10 values Then I test collision for all of these 10 "Mouse Objects" and choose the one that seperate between "no collision" and "collision". I feel this method is super non-efficient. I am not sure the way other people find the time-of-contact or the position-of-contact when "Object A" can move.

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  • What are some techniques I can use to refactor Object Oriented code into Functional code?

    - by tieTYT
    I've spent about 20-40 hours developing part of a game using JavaScript and HTML5 canvas. When I started I had no idea what I was doing. So it started as a proof of concept and is coming along nicely now, but it has no automated tests. The game is starting to become complex enough that it could benefit from some automated testing, but it seems tough to do because the code depends on mutating global state. I'd like to refactor the whole thing using Underscore.js, a functional programming library for JavaScript. Part of me thinks I should just start from scratch using a Functional Programming style and testing. But, I think refactoring the imperative code into declarative code might be a better learning experience and a safer way to get to my current state of functionality. Problem is, I know what I want my code to look like in the end, but I don't know how to turn my current code into it. I'm hoping some people here could give me some tips a la the Refactoring book and Working Effectively With Legacy Code. For example, as a first step I'm thinking about "banning" global state. Take every function that uses a global variable and pass it in as a parameter instead. Next step may be to "ban" mutation, and to always return a new object. Any advice would be appreciated. I've never taken OO code and refactored it into Functional code before.

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  • Is learning the Caché database hard coming from relational databases and object oriented programming

    - by Edelcom
    I am currently running the local version of Caché on my system in order to determine if I can (and will) take on a new possible project. The current project uses Delphi 7 as a front end calling a Caché dll where the business logic is stored in the database. I have a background of Sqlserver and Firebird (and before Access and Paradox) as databases. I use Delphi 7 for 95% of my Windows development, so I know about object programming. I would like to recieve opinions from persons having used Caché and either SqlServer, Firebird or Oracle and having developed in Delphi (or C++ or C# - an object oriented language). I have read the pro's and con's from other questions, but I am not asking for this, I need input from Caché developers. Thanks in advance.

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  • BizTalk Pipeline Component Error: "Object reference not set to an instance of an object"

    - by Stuart Brierley
    Yesterday I posted about my BizTalk Archiving Pipeline Component, which can be found on Codeplex if anyone is interested in taking a look. During testing of this component I began to encounter an error whereby the component would throw an "Object reference not set to an instance of an object" error when processing as a part of a Custom Pipeline. This was occurring when the component was reading a ReadOnlySeekableStream so that the data can be archived to file, but the actual code throwing the error was somewhere in the depths of the Microsoft.BizTalk.Streaming stack. It turns out that there is a known issue where this exception can be thrown because the garbage collector has disposed of of the stream before execution of the custom pipeline has completed. To get around this you need to add the streams in your code to the pipeline context resource tracker.   So a block of my code goes from:                         originalStrm = bodyPart.GetOriginalDataStream();                         if (!originalStrm.CanSeek)                         {                             ReadOnlySeekableStream seekableStream = new ReadOnlySeekableStream(originalStrm);                             inmsg.BodyPart.Data = seekableStream;                             originalStrm = inmsg.BodyPart.Data;                         }                         fileArchive = new FileStream(FullPath, FileMode.Create, FileAccess.Write);                         binWriter = new BinaryWriter(fileArchive);                         byte[] buffer = new byte[bufferSize];                         int sizeRead = 0;                         while ((sizeRead = originalStrm.Read(buffer, 0, bufferSize)) != 0)                         {                             binWriter.Write(buffer, 0, sizeRead);                         } to                         originalStrm = bodyPart.GetOriginalDataStream();                         if (!originalStrm.CanSeek)                         {                             ReadOnlySeekableStream seekableStream = new ReadOnlySeekableStream(originalStrm);                             inmsg.BodyPart.Data = seekableStream;                             originalStrm = inmsg.BodyPart.Data;                         }                         pc.ResourceTracker.AddResource(originalStrm);                         fileArchive = new FileStream(FullPath, FileMode.Create, FileAccess.Write);                         binWriter = new BinaryWriter(fileArchive);                         byte[] buffer = new byte[bufferSize];                         int sizeRead = 0;                         while ((sizeRead = originalStrm.Read(buffer, 0, bufferSize)) != 0)                         {                             binWriter.Write(buffer, 0, sizeRead);                         } So far this seems to have solved the issue, the error is no more, and my archive component is continuing its way through testing.

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  • Rotating object around moving object/player in 2D

    - by Boston
    I am trying to implement a camera which rotates around the world around the player. I have found many solutions online to the task of rotating an object about the origin, or about an arbitrary point. The procedure seems to be to translate the point to be rotated about to the origin, perform the rotation, translate back, then draw. I have gotten this working for rotation around the origin as well as for a fixed point. Rotation of objects around the player works as well, provided the player does not move. However, if the objects are rotated around the player by some non-zero degree, if the player moves after the rotation it causes the rotated objects to move as well. I probably have done a poor job explaining this so here's an image: http://i.imgur.com/1n63iWR.gif And here's the code for the behavior: renderx = (Ox - Px)*cos(camAngle) - (Oy - Py)*sin(camAngle) + Px; rendery = (Ox - Px)*sin(camAngle) + (Oy - Py)*cos(camAngle) + Py; Where (Ox,Oy) is the actual position of the object to be rotated and (Px,Py) is the actual position of the player. Any ideas? I am using C++ with SDL2.0.

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  • Storing Templates and Object-Oriented vs Relational Databases

    - by syrion
    I'm designing some custom blog software, and have run into a conundrum regarding database design. The software requires that there be multiple content types, each of which will require different entry forms and presentation templates. My initial instinct is to create these content types as objects, then serialize them and store them in the database as JSON or YAML, with the entry forms and templates as simple strings attached to the "contentTypes" table. This seems cumbersome, however. Are there established best practices for dealing with this design? Is this a use case where I should consider an object database? If I should be using an object database, which should I consider? I am currently working in Python and would prefer a capable Python library, but can move to Java if need be.

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  • javascript object access performance

    - by youdontmeanmuch
    In Javascript, when your getting a property of an object, is there a performance penalty to getting the whole object vs only getting a property of that object? Also Keep in mind I'm not talking about DOM access these are pure simple Javascript objects. For example: Is there some kind of performance difference between the following code: Assumed to be faster but not sure: var length = some.object[key].length; if(length === condition){ // Do something that doesnt need anything inside of some.object[key] } else{ var object = some.object[key]; // Do something that requires stuff inside of some.object[key] } I think this would be slower but not sure if it matters. var object = some.object[key]; if(object.length === condition){ // Do something that doesnt need anything inside of some.object[key] } else{ // Do something that requires stuff inside of some.object[key] }

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  • Unittesting aspect-oriented features.

    - by Tomas Brambora
    Hi, I'd like to know what would you propose as the best way to unit test aspect-oriented application features (well, perhaps that's not the best name, but it's the best I was able to come up with :-) ) such as logging or security? These things are sort of omni-present in the application, so how to test them properly? E.g. say that I'm writing a Cherrypy web server in Python. I can use a decorator to check whether the logged-in user has the permission to access a given page. But then I'd need to write a test for every page to see whether it works oK (or more like to see that I had not forgotten to check security perms for that page). This could maybe (emphasis on maybe) be bearable if logging and/or security were implemented during the web server "normal business implementation". However, security and logging usually tend to be added to the app as an afterthough (or maybe that's just my experience, I'm usually given a server and then asked to implement security model :-) ). Any thoughts on this are very welcome. I have currently 'solved' this issue by, well - not testing this at all. Thanks.

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  • Object oriented design suggestion

    - by pocoa
    Here is my code: class Soldier { public: Soldier(const string &name, const Gun &gun); string getName(); private: Gun gun; string name; }; class Gun { public: void fire(); void load(int bullets); int getBullets(); private: int bullets; } I need to call all the member functiosn of Gun over a Soldier object. Something like: soldier.gun.fire(); or soldier.getGun().load(15); So which one is a better design? Hiding the gun object as a private member and access it with getGun() function. Or making it a public member? Or I can encapsulate all these functions would make the implementation harder: soldier.loadGun(15); // calls Gun.load() soldier.fire(); // calls Gun.fire() So which one do you think is the best?

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  • help Implementing Object Oriented ansi-C approach??

    - by No Money
    Hey there, I am an Intermediate programmer in Java and know some of the basics in C++. I recently started to scam over "C language" [please note that i emphasized on C language and want to stick with C as i found it to be a perfect tool, so no need for suggestions focusing on why should i move back to C++ or Java]. Moving on, I code an Object Oriented approach in C but kindda scramble with the pointers part. Please understand that I am just a noob trying to extend my knowledge beyond what i learned in High School. Here is my code..... #include <stdio.h> typedef struct per{ int privateint; char *privateString; struct per (*New) (); void (*deleteperOBJ) (struct t_person *); void (*setperNumber) ((struct*) t_person,int); void (*setperString) ((struct*) t_person,char *); void (*dumpperState) ((struct*) t_person); }t_person; void setperNumber(t_person *const per,int num){ if(per==NULL) return; per->privateint=num; } void setperString(t_person *const per,char *string){ if(per==NULL) return; per->privateString=string; } void dumpperState(t_person *const per){ if(per==NULL) return; printf("value of private int==%d\n", per->privateint); printf("value of private string==%s\n", per->privateString); } void deleteperOBJ(struct t_person *const per){ free((void*)t_person->per); t_person ->per = NULL; } main(){ t_person *const per = (struct*) malloc(sizeof(t_person)); per = t_person -> struct per -> New(); per -> setperNumber (t_person *per, 123); per -> setperString(t_person *per, "No money"); dumpperState(t_person *per); deleteperOBJ(t_person *per); } Just to warn you, this program has several errors and since I am a beginner I couldn't help except to post this thread as a question. I am looking forward for assistance. Thanks in advance.

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  • Newton Game Dynamics: Making an object not affect another object

    - by Boreal
    I'm going to be using Newton in my networked action game with Mogre. There will be two "types" of physics object: global and local. Global objects will be kept in sync for everybody; these include the players, projectiles, and other gameplay-related objects. Local objects are purely for effect, like ragdolls, debris, and particles. Is there a way to make the global objects affect the local objects without actually getting affected themselves? I'd like debris to bounce off of a tank, but I don't want the tank to respond in any way.

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  • Breaking up a large PHP object used to abstract the database. Best practices?

    - by John Kershaw
    Two years ago it was thought a single object with functions such as $database->get_user_from_id($ID) would be a good idea. The functions return objects (not arrays), and the front-end code never worries about the database. This was great, until we started growing the database. There's now 30+ tables, and around 150 functions in the database object. It's getting impractical and unmanageable and I'm going to be breaking it up. What is a good solution to this problem? The project is large, so there's a limit to the extent I can change things. My current plan is to extend the current object for each table, then have the database object contain these. So, the above example would turn into (assume "user" is a table) $database->user->get_user_from_id($ID). Instead of one large file, we would have a file for every table.

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  • Questioning one of the arguments for dependency injection: Why is creating an object graph hard?

    - by oberlies
    Dependency injection frameworks like Google Guice give the following motivation for their usage (source): To construct an object, you first build its dependencies. But to build each dependency, you need its dependencies, and so on. So when you build an object, you really need to build an object graph. Building object graphs by hand is labour intensive (...) and makes testing difficult. But I don't buy this argument: Even without dependency injection, I can write classes which are both easy to instantiate and convenient to test. E.g. the example from the Guice motivation page could be rewritten in the following way: class BillingService { private final CreditCardProcessor processor; private final TransactionLog transactionLog; // constructor for tests, taking all collaborators as parameters BillingService(CreditCardProcessor processor, TransactionLog transactionLog) { this.processor = processor; this.transactionLog = transactionLog; } // constructor for production, calling the (productive) constructors of the collaborators public BillingService() { this(new PaypalCreditCardProcessor(), new DatabaseTransactionLog()); } public Receipt chargeOrder(PizzaOrder order, CreditCard creditCard) { ... } } So there may be other arguments for dependency injection (which are out of scope for this question!), but easy creation of testable object graphs is not one of them, is it?

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  • Design in "mixed" languages: object oriented design or functional programming?

    - by dema80
    In the past few years, the languages I like to use are becoming more and more "functional". I now use languages that are a sort of "hybrid": C#, F#, Scala. I like to design my application using classes that correspond to the domain objects, and use functional features where this makes coding easier, more coincise and safer (especially when operating on collections or when passing functions). However the two worlds "clash" when coming to design patterns. The specific example I faced recently is the Observer pattern. I want a producer to notify some other code (the "consumers/observers", say a DB storage, a logger, and so on) when an item is created or changed. I initially did it "functionally" like this: producer.foo(item => { updateItemInDb(item); insertLog(item) }) // calls the function passed as argument as an item is processed But I'm now wondering if I should use a more "OO" approach: interface IItemObserver { onNotify(Item) } class DBObserver : IItemObserver ... class LogObserver: IItemObserver ... producer.addObserver(new DBObserver) producer.addObserver(new LogObserver) producer.foo() //calls observer in a loop Which are the pro and con of the two approach? I once heard a FP guru say that design patterns are there only because of the limitations of the language, and that's why there are so few in functional languages. Maybe this could be an example of it? EDIT: In my particular scenario I don't need it, but.. how would you implement removal and addition of "observers" in the functional way? (I.e. how would you implement all the functionalities in the pattern?) Just passing a new function, for example?

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