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• Classes as a compilation unit

  - by Yannbane

  If "compilation unit" is unclear, please refer to this. However, what I mean by it will be clear from the context. Edit: my language allows for multiple inheritance, unlike Java. I've started designing+developing my own programming language for educational, recreational, and potentially useful purposes. At first, I've decided to base it off Java. This implied that I would have all the code be written inside classes, and that code compiles to classes, which are loaded by the VM. However, I've excluded features such as interfaces and abstract classes, because I found no need for them. They seemed to be enforcing a paradigm, and I'd like my language not to do that. I wanted to keep the classes as the compilation unit though, because it seemed convenient to implement, familiar, and I just liked the idea. Then I noticed that I'm basically left with a glorified module system, where classes could be used either as "namespaces", providing constants and functions using the static directive, or as templates for objects that need to be instantiated ("actual" purpose of classes in other languages). Now I'm left wondering: what are the benefits of having classes as compilation units? (Also, any general commentary on my design would be much appreciated.)

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• How do I find actors in an area on a poly-precise basis?

  - by Almo

  Ok, I've been asking various questions and getting some good answers, but I think I need to rethink my method, so I'll describe the problem. I have a player who has a big blue box in front of him. This box shows which KActors will be pushed when he pulls the trigger: Currently, the blue box spawns a descendant of Actor which checks collision to see which KActors are touching it: foreach Owner.TouchingActors(class'DynamicSMActor', DynamicActorItt) { // do stuff } The problem is, if you check for touching between Actors and KActors, it looks like it does a plain axis-aligned bounding-box collision. The power will push the box on the lower right, when it's clear it's not touching the blue box. How should I do this properly? I just need a way to find out which KActors are touching that area, on a poly-by-poly level. These collisions are only done with rectangular boxes and simple sphere collision; we are aware of the potential for performance issues with complex objects and poly-collision. I've tried making the collision checker a KActor, but it doesn't report any TouchingActors. This issue is causing us trouble in a lot of other places as well. So solving this problem is a core issue in our game.

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• Guidelines for creating referentially transparent callables

  - by max

  In some cases, I want to use referentially transparent callables while coding in Python. My goals are to help with handling concurrency, memoization, unit testing, and verification of code correctness. I want to write down clear rules for myself and other developers to follow that would ensure referential transparency. I don't mind that Python won't enforce any rules - we trust ourselves to follow them. Note that we never modify functions or methods in place (i.e., by hacking into the bytecode). Would the following make sense? A callable object c of class C will be referentially transparent if: Whenever the returned value of c(...) depends on any instance attributes, global variables, or disk files, such attributes, variables, and files must not change for the duration of the program execution; the only exception is that instance attributes may be changed during instance initialization. When c(...) is executed, no modifications to the program state occur that may affect the behavior of any object accessed through its "public interface" (as defined by us). If we don't put any restrictions on what "public interface" includes, then rule #2 becomes: When c(...) is executed, no objects are modified that are visible outside the scope of c.__call__. Note: I unsuccessfully tried to ask this question on SO, but I'm hoping it's more appropriate to this site.

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• Returning a flexible datatype from a C++ function

  - by GavinH

  I'm developing for a legacy C++ application which uses ODBC for it's data access. Coming from a C# background, I really miss the ADO style of data access. I'm writing a wrapper (because we can't actually use ADO) to make our data access less painful. This means no char arrays, no manual text blob streaming, and no declaritive column binding. I'm struggling with how to store / return data values. In C# at least, you can declare an object and cast it to whatever (as long as the type is convertable). My current C++ solution is to use boost::any to store the data value in a custom DataColumnValue object. This class has conversion and assignment operators to the various types used in our app (more than 10). There's a bit of complexity here because if you store an int in the boost::any and try to boost::any_cast<long> you get a boost::bad_any_cast. Client objects shouldn't have to know how the value is stored internally. Does anyone have any experience trying to store / return values whose types are only known at runtime? Is there a better / cleaner way?

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• What's the point of the Prototype design pattern?

  - by user1905391

  So I'm learning about design patterns in school. Many of them are silly little ideas, but nevertheless solve some recurring problems(singleton, adapters, asynchronous polling, ect). But today I was told about the so called 'Prototype' design pattern. I must be missing something, because I don't see any benefits from it. I've seen people online say it's faster than using "new"' but this is doesn't make any sense, since at some point, regardless how the new object is created, memory needs to be allocated for it ect. Furthermore, doesn't this pattern run in the same circles as the 'chicken or egg' problem? By this I mean, since the prototype pattern essentially is just cloning objects, at some point the original object must be created itself (ie, not cloned). So this would mean, that I would need to have an existing copy of every object that I would ever want to clone already ready to clone? Seems stupid to me. Can anyone explain what the use of this pattern is? Original post: http://stackoverflow.com/questions/13887704/whats-the-point-of-the-prototype-design-pattern

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• Reversing animated sprites

  - by brandon sedgwick

  I have created a sprite sheet of which consists of 6 frames with a character moving legs each frame, now I have coded it so that the animation is running successfully from frame 1 to 6, however I am trying to reverse this so then when it goes from 1 to 6 instead of restarting it go's 6 to 1 in a continuous loop. The coding for current animation is: void SpriteGame::Update(int tickTotal, int tickDelta) { //This is where you manage the state of game objects if ( tickTotal >= this->playerLastFrameChange + 4) { //Four ticks have elapsed since the last frame change this->playerFrame = this->playerFrame + 1; this->playerLastFrameChange = tickTotal; //We've just changed the frame if (this->playerFrame >= this->playerSheetLength) { this->playerFrame = playerLastFrameChange + 4; } //Frame has changed so change the source rectangle this->playerSourceRect->left = this->playerFrame * 64; this->playerSourceRect->top = 0; this->playerSourceRect->right = (this->playerFrame + 1) * 64; this->playerSourceRect->bottom = 64; } } any help please I am using DirectX11 as thats what we are being told to use as its for an win 8 game.

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• Fast, accurate 2d collision

  - by Neophyte

  I'm working on a 2d topdown shooter, and now need to go beyond my basic rectangle bounding box collision system. I have large levels with many different sprites, all of which are different shapes and sizes. The textures for the sprites are all square png files with transparent backgrounds, so I also need a way to only have a collision when the player walks into the coloured part of the texture, and not the transparent background. I plan to handle collision as follows: Check if any sprites are in range of the player Do a rect bounding box collision test Do an accurate collision (Where I need help) I don't mind advanced techniques, as I want to get this right with all my requirements in mind, but I'm not sure how to approach this. What techniques or even libraries to try. I know that I will probably need to create and store some kind of shape that accurately represents each sprite minus the transparent background. I've read that per pixel is slow, so given my large levels and number of objects I don't think that would be suitable. I've also looked at Box2d, but haven't been able to find much documentation, or any examples of how to get it up and running with SFML.

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• Strategy to store/average logs of pings

  - by José Tomás Tocino

  I'm developing a site to monitor web services. The most basic type of check is sending a ping, storing the response time in a CheckLog object. By default, PingCheck objects are triggered every minute, so in one hour you get 60 CheckLogs and in one day you get 1440 CheckLogs. That's a lot of them, I don't need to store such level of detail, so I've set a up collapsing mechanism that periodically takes the uncollapsed CheckLogs older than 24h and collapses (averages) them in intervals of 30 minutes. So, if you have 360 CheckLogs that have been saved from 0:00 to 6:00, after collapsing you retain just 12 of them. The problem.. well, is this: After averaging the response times, the graph changes drastically. What can I do to improve this? Guess one option could be narrowing the interval duration to 15 min. I've seen the graphs at the GitHub status page and they do not seem to suffer from this problem. I'd appreciate any kind of information you could give me about this area.

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• Problems moving a rectangle in Pygame.

  - by Yann Core

  Hi guys! I'm making a game in Pygame and I want to be able to target enemy unit. I made it so when I click on them a variable "targeted" becomes true, and stays true until I click somewhere else on the screen. I also want targeted units to have a small green circle around them, so I made it in GEDIT. I have made a function that draws everything on the screen (the background, the player, objects, etc) and in the part where it draws the units it checks if the variable "targeted" is true and if it is it should move that little green circle over the enemy units. here is the code that does that: screen.blit(enemy_unit.pic, enemy_unit.rect) #draw the unit if enemy_unit.targeted == True: #if the unit has been targeted then draw a circle over it target_rect.move_ip(enemy_unit.pos) #move the circle to the unit target_rect.fit(enemy_unit.rect) #there are some bigger units and some smaller ones, so we have to "scale" the circle screen.blit(target_pic, target_rect) #actually draw the circle This doesn't work, when I target the unit the circle just appears for a 1/5 of second next (not on, but just next) to the unit and then disappears. I am sure that I am keeping a good track of "enemy_unit.pos" because I tested it (I added a piece of code that would print one units position and mouse's position every time i clicked the mouse and when i was near him the numbers were same). If you could give me a hint about what I'm doing wrong. I think its in move_ip function, but I tried just move and it didn't work either (the circle didn't even show at all)!

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• Why am I seeing so many instantiable classes without state?

  - by futlib

  I'm seeing a lot of instantiable classes in the C++ and Java world that don't have any state. I really can't figure out why people do that, they could just use a namespace with free functions in C++, or a class with a private constructor and only static methods in Java. The only benefit I can think of is that you don't have to change most of your code if you later decide that you want a different implementation in certain situations. But isn't that a case of premature design? It could be turned into a class later, when/if it becomes appropriate. Am I getting this wrong? Is it not OOP if I don't put everything into objects (i.e. instantiated classes)? Then why are there so many utility namespaces and classes in the standard libraries of C++ and Java? Update: I've certainly seen a lot examples of this in my previous jobs, but I'm struggling to find open source examples, so maybe it's not that common after all. Still, I'm wondering why people do it, and how common it is.

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• Best approach for tracking dependent state

  - by Pace

  Let's pretend I work on a project tracking application. The application is a database backed, server hosted, web application. In this application there are Projects which have many Activities which have many Tasks. A Task has two date fields an originalDueDate and a projectedDueDate. In addition, there are dynamic fields on the Activities and the Projects which indicate whether the Activity or Project is behind schedule based on the projected due dates of the child tasks and various other variables such as remaining buffer time, etc. There are a number of things that can cause the projectedDueDate to change. For example, an employee working on the project may (via a server request) enter in a shipping delay. Alternatively, a site may (via a server request) enter in an unexpected closure. When any of these things occur I need to not only update the projectedDueDate of the Task but also trigger the corresponding Project and Activity to update as well. What is the best way to do this? I've thought of the observer pattern but I don't keep a single copy of all these objects in memory. When a request comes in, I query the Task in from the database, at that point there is no associated Activity in memory that would be a listener. I could remove the ability to query for Tasks and force the application to query first by Project, then by Activity (in context of Project), then by task (in context of Activity) adding the observer relationships at each step but I'm not sure if that is the best way. I could setup a database event listening system so when a Task modified event is dispatched I have a handler which queries for the Activity at that point. I could simply setup a two-way relationship between Task and Activity so that the Task knows about the parent Activity and when the Task updates his state the Task grabs his parent and updates state. Right now I'm stuck considering all the options and am wondering if any single approach (doesn't have to be a listed approach) is jumping out at others as the best approach.

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• Domain model integration using JSON capable DTOs

  - by g-makulik

  I'm a bit confused about architectural choices for the java/web-applications world. The background is I have a system with certain hardware components (that introduce system immanent active behavior) and a configuration database for system meta and HW-components configuration data (these are even usually self contained, since the HW-components persist configuration data anyway). For realization of the configuration/status data exchange protocol with the HW-components we have chosen the Google Protobuf format, which works well for the directly wired communication with these components. Now we want to develop an abstract model (domain model) for those HW-components and I have the feeling that a plain Java class model would fit best for this (c++ implementation seems to have too much implementation/integration overhead with viable language-bridge interfaces). Google Protobuf message definitions could still serve well to describe DTO objects used to interact with a domain model API. But integrating Google Protobuf messages client side for e.g. data binding in the current view doesn't seem to be a good choice. I'm thinking about some extra serialization features, e.g. for JSON based data exchange with the views/controllers. Most lightweight solutions seem to involve a python based presentation layer using JSON based data transfer (I'm at least not sure to be fully informed about this). Is there some lightweight (applicable for a limited ARM Linux platform) framework available, supporting such architecture to realize a web-application?

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• Android Bitmap: Collision Detecting

  - by Aekasitt Guruvanich

  I am writing an Android game right now and I would need some help in the collision of the Pawns on screen. I figured I could run a for loop on the Player class with all Pawn objects on the screen checking whether or not Width*Height intersects with each other, but is there a more efficient way to do this? And if you do it this way, many of the transparent pixel inside the rectangular area will also be considered as collision as well. Is there a way to check for collision between Bitmap on a Canvas that disregard transparent pixels? The class for player is below and the Pawn class uses the same method of display. Class Player { private Resources res; // Used for referencing Bitmap from predefined location private Bounds bounds; // Class that holds the boundary of the screen private Bitmap image; private float x, y; private Matrix position; private int width, height; private float velocity_x, velocity_y; public Player (Resources resources, Bounds boundary) { res = resources; bounds = boundary; image = BitmapFactory.decodeResource(res, R.drawable.player); width = image.getWidth(); height = image.getHeight(); position = new Matrix(); x = bounds.xMax / 2; // Initially puts the Player in the middle of screen y = bounds.yMax / 2; position.preTranslate(x,y); } public void draw(Canvas canvas) { canvas.drawBitmap(image, position, null); } }

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• How to persuade C fanatics to work on my C++ open source project?

  - by paperjam

  I am launching an open-source project into a space where a lot of the development is still done Linux-kernel-style, i.e. C-language with a low-level mindset. There are multiple benefits to C++ in our space but I fear those used to working in C will be scared off. How can I make the case for the benefits of C++? Specifically, the following C++ attributes are very valuable: concept of objects and reference-counting pointers - really don't want to have to malloc(sizeof(X)) or memcpy() structs templates for specialising whole bodies of code with specific performance optimizations and for avoiding duplication of code. template metaprogramming related to the above syntactic sweetness available (e.g. operator overloading, to be used in very small doses) STL Boost libraries Many of the knee-jerk negative reactions to C++ are illfounded. Performance does not suffer: modern compilers can flatten dozens of call stack levels and avoid bloat through wide use of template specializations. Granted, when using metaprogramming and building multiple specializations of a large call tree, compile time is slower but there are ways to mitigate this. How can I sell C++?

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• OOP Design: relationship between entity classes

  - by beginner_

  I have at first sight a simple issue but can't wrap my head around on how to solve. I have an abstract class Compound. A Compound is made up of Structures. Then there is also a Container which holds 1 Compound. A "special" implementation of Compound has Versions. For that type of Compound I want the Container to hold the Versionof the Compound and not the Compound itself. You could say "just create an interface Containable" and a Container holds 1 Containable. However that won't work. The reason is I'm creating a framework and the main part of that framework is to simplify storing and especially searching for special data type held by Structure objects. Hence to search for Containers which contain a Compound made up of a specific Structure requires that the "Path" from Containerto Structure is well defined (Number of relationships or joins). I hope this was understandable. My question is how to design the classes and relationships to be able to do what I outlined.

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• How can I use an object pool for optimization in AndEngine?

  - by coder_For_Life22

  I have read up on a tutorial that allows you to reuse sprites that are re-added to the scene such as bullets from a gun or any other objects using an ObjectPool. In my game i have a variation of sprites about 6 all together with different textures. This is how the object pool is set up with its own class extending Java's GenericPool class public class BulletPool extends GenericPool<BulletSprite> { private TextureRegion mTextureRegion; public BulletPool(TextureRegion pTextureRegion) { if (pTextureRegion == null) { // Need to be able to create a Sprite so the Pool needs to have a TextureRegion throw new IllegalArgumentException("The texture region must not be NULL"); } mTextureRegion = pTextureRegion; } /** * Called when a Bullet is required but there isn't one in the pool */ @Override protected BulletSprite onAllocatePoolItem() { return new BulletSprite(mTextureRegion); } /** * Called when a Bullet is sent to the pool */ @Override protected void onHandleRecycleItem(final BulletSprite pBullet) { pBullet.setIgnoreUpdate(true); pBullet.setVisible(false); } /** * Called just before a Bullet is returned to the caller, this is where you write your initialize code * i.e. set location, rotation, etc. */ @Override protected void onHandleObtainItem(final BulletSprite pBullet) { pBullet.reset(); } } As you see here it takes a TextureRegion parameter. The only problem i am facing with this is that i need to have 6 different sprites recycled and reused in the ObjectPool. This ObjectPool is set up to only use one TextureRegion. Any idea's or suggestions on how to do this?

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• How should I structure the implementation of turn-based board game rules?

  - by Setzer22

  I'm trying to create a turn-based strategy game on a tilemap. I'm using design by component so far, but I can't find a nice way to fit components into the part I want to ask. I'm struggling with the "game rules" logic. That is, the code that displays the menu, allows the player to select units, and command them, then tells the unit game objects what to do given the player input. The best way I could thing of handling this was using a big state machine, so everything that could be done in a "turn" is handled by this state machine, and the update code of this state machine does different things depending on the state. However, this approach leads to a large amount of code (anything not model-related) going into a big class. Of course I can subdivide this big class into more classes, but it doesn't feel modular and upgradable enough. I'd like to know of better systems to handle this in order to be able to upgrade the game with new rules without having a monstruous if/else chain (or switch / case, for that matter). Any ideas? What specific design pattern other than MVC should I be using?

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• How to reset a List c# and XNA [on hold]

  - by P3erfect

  I need to do a "retry" option when the player finishes the game.For doing this I thought to reset the lists of Monsters and other objects that moved at the first playing or which have been "killed".for example I have a list like that: //the enemy1 class is already done // in Game1 I declare it List<enemy1> enem1 = new List<enemy1>(); //Initialize method List<enemy1> enem1 = new List<enemy1>(); //LoadContent foreach (enemy1 enemy in enem1) { enemy.Load(Content); } enem1.Add(new enemy1(Content.Load<Texture2D>("enemy"), new Vector2(5900, 12600))); //Update foreach (enemy1 enemy in enem1) { enemy.Update(gameTime); } //after being shoted the enemies disappear and i remove them //if the monsters are shoted the bool "visible" goes from false to true for (int i = enem1.Count - 1; i >= 0; --i) { if (enem1[i].visible == true) enem1.RemoveAt(i); } //Draw foreach (enemy1 enemy in enem1) { if(enemy.visble==false) { enemy.Draw(spriteBatch, gameTime); } } //So my problem is to restart the game. I did this in Update method if(lost==false) { //update all the things... } if(lost==true)//this is if I die { //here I have to put the code that restore the list //I tried: foreach (enemy1 enemy in enem1) { enemy.visible=false; } player.life=3;//initializing the player,points,time player.position=initialPosition; points=0; time=0; }//the player works.. } } they should be drawn again but if I removed them they won't be drawn anymore.If I don't remove them ,instead, the enemies are in different places (because they follow me). Any suggestions to restore or reinitialize the list??

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• Windows Phone 7 v. Windows 8 Metro &ldquo;Same but Different&rdquo;

  - by ryanabr

  I have been doing development on both the Windows Phone 7 and Windows 8 Metro style applications over the past month and have really been enjoying doing both. What is great is that Silverlight is used for both development platforms. What is frustrating is the "Same but Different" nature of both platforms. Many similar services and ways of doing things are available on both platforms, but the objects, namespaces, and ways of handling certain cases are different. I almost had a heart attack when I thought that XmlDocument had been removed from the new WinRT. I was relived (but a little annoyed)  when I found out that it had shifted from the "System.Xml" namespace to the "Windows.Data.Xml.Dom" namespace. In my opinion this is worse than deprecating and reintroducing it since there isn't the lead time to know that the change is coming, maker changes and adjust. I also think the breaks the compatibility that is advertised between the WinRT and .NET framework from a programming perspective, as the code base will have to be physically different if compiled for one platform versus the other. Which brings up another issue, the need for separate DLLs with for the different platforms that contain the same C# code behind them which seems like the beginning of a code maintenance headache. Historically, I have kept source files "co-located" with the projects that they are compiled into. After doing some research, I think I will end up keeping "common" files that need to be compiled in to DLLs for the different platforms in a seperate location in TFS, not directly included in any one Visual Studio project, but added as links in the project that would get compiled into the windows 7 phone, or Windows 8. This will work fine, except for the case where dependencies don't line up for each platform as described above, but will work fine for base classes that do the raw work at the most basic programming level.

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• What makes one language any better than another when both are designed for the same goals? [closed]

  - by Justin808

  I'm in the process of creating a grammar for a scripting language but as I'm working on it I started to wonder what makes a language good in the first place. I know the goals for my script but there are always 1000 different ways to go about doing things. Goals: Easy to use and understand (not my grandma could do it easy, but the secretary at the front desk could do it or the VP of marketing could do it type of easy) No user defined functions or subroutines. Its use would be in events of objects in a system similar to HyperCard. Conceptually I was thinking of a language like this: set myVariable to 'Hello World' set counter to 0 repeat 5 times with x begin set counter to counter add x end set myVariable to myVariable plus ' ' plus counter popup myVariable set text of label named 'label' to 'new text' set color of label named 'label' to blue The end result would popup a dialog with the contents Hello World 15 it would also change the text of a label and make it blue. But I could do the same thing 1000 different ways. So what makes one language any better than another when both are designed for the same goals?

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• C++ Parallel Asynchonous task

  - by Doodlemeat

  I am currently building a randomly generated terrain game where terrain is created automatically around the player. I am experiencing lag when the generated process is active, as I am running quite heavy tasks with post-processing and creating physics bodies. Then I came to mind using a parallel asynchronous task to do the post-processing for me. But I have no idea how I am going to do that. I have searched for C++ std::async but I believe that is not what I want. In the examples I found, a task returned something. I want the task to change objects in the main program. This is what I want: // Main program // Chunks that needs to be processed. // NOTE! These chunks are already generated, but need post-processing only! std::vector<Chunk*> unprocessedChunks; And then my task could look something like this, running like a loop constantly checking if there is chunks to process. // Asynced task if(unprocessedChunks.size() > 0) { processChunk(unprocessedChunks.pop()); } I know it's not far from easy as I wrote it, but it would be a huge help for me if you could push me at the right direction. In Java, I could type something like this: asynced_task = startAsyncTask(new PostProcessTask()); And that task would run until I do this: asynced_task.cancel();

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• Transforms in Box2D

  - by user1264811

  I'm attempting to implement a camera in my game. I had it working for regular objects, but I began using Box2D and obviously things changed a bit. I have a Body object that I want to draw at the center of the screen. Basically what I'm doing is subtracting the viewportX and viewportY to the Body. I use this code that currently is not working as it should: public void paint(Graphics2D g, int viewportX, int viewportY) { Transform xf = new Transform(); // m_body is the Body object xf.set(m_body.getTransform()); // Here what I attemp to do is take the transform and alter it // by the viewportX and Y, which is something like **-240, -150**. // Why is it negative? Because an object has coordinates 500, 300 would be displayed // at 160, 150 when the subtraction is done. // With the DrawUtils.toScale(), it's just how I convert the units from JBox2D units // to my units. Vec2 v = Transform.mulTrans(xf, new Vec2(DrawUtils.toScale(-viewportX), DrawUtils.toScale(-viewportY))); // Set the new transform to the new vector. Keep the old angle. xf.set(v, xf.q.getAngle()); g.setColor(Color.white); // I know for a fact that the following method works 100%. It correctly displays // my object, just that it doesn't follow it. for (Fixture f = m_body.getFixtureList(); f != null; f = f.getNext()) DrawUtils.drawShape(f, xf); } Hopefully I didn't over comment this and you understand my problem. I don't want to alter the actual physics position of the object, I just want to display it in the center.

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• Recommended design pattern for object with optional and modifiable attributtes? [on hold]

  - by Ikuzen

  I've been using the Builder pattern to create objects with a large number of attributes, where most of them are optional. But up until now, I've defined them as final, as recommended by Joshua Block and other authors, and haven't needed to change their values. I am wondering what should I do though if I need a class with a substantial number of optional but non-final (mutable) attributes? My Builder pattern code looks like this: public class Example { //All possible parameters (optional or not) private final int param1; private final int param2; //Builder class public static class Builder { private final int param1; //Required parameters private int param2 = 0; //Optional parameters - initialized to default //Builder constructor public Builder (int param1) { this.param1 = param1; } //Setter-like methods for optional parameters public Builder param2(int value) { param2 = value; return this; } //build() method public Example build() { return new Example(this); } } //Private constructor private Example(Builder builder) { param1 = builder.param1; param2 = builder.param2; } } Can I just remove the final keyword from the declaration to be able to access the attributes externally (through normal setters, for example)? Or is there a creational pattern that allows optional but non-final attributes that would be better suited in this case?

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• SQL RDBMS : one query or multiple calls

  - by None None

  After looking around the internet, I decided to create DAOs that returned objects (POJOs) to the calling business logic function/method. For example: a Customer object with a Address reference would be split in the RDBMS into two tables; Customer and ADDRESS. The CustomerDAO would be in charge of joining the data from the two tables and create both an Address POJO and Customer POJO adding the address to the customer object. Finally return the fulll Customer POJO. Simple, however, now i am at a point where i need to join three or four tables and each representing an attribute or list of attributes for the resulting POJO. The sql will include a group by but i will still result with multiple rows for the same pojo, because some of the tables are joining a one to many relationship. My app code will now have to loop through all the rows trying to figure out if the rows are the same with different attributes or if the record should be a new POJO. Should I continue to create my daos using this technique or break up my Pojo creation into multiple db calls to make the code easier to understand and maintain?

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• Efficiency of iterators and alternatives? [migrated]

  - by user48037

  I have the following code for my game tiles: std::vector<GameObject_Tile*>::iterator it; for(int y = 0; y < GAME_TILES_Y; y++) { for(int x = 0; x < GAME_TILES_X; x++) { for (it = gameTiles[x][y].tiles.begin() ; it != gameTiles[x][y].tiles.end(); ++it) {}}} tiles is: struct Game_Tile { // More specific object types will be added here eventually vector<GameObject_Tile*> tiles; }; My problem is that if I change the vector to just be a single GameObject_Tile* instead and remove the iterator line in the loop I go from about 200fps to 450fps. Some context: The vector/pointer only contains one object in both scenarios. I will eventually need to store multiple, but for testing I just set it to a single pointer. The loop goes through 2,300 objects each frame and draws them. I would like to point out that if I remove the Draw (not seen int he example) method, I gain about 30 frames in both scenarios, the issue is the iteration. So I am wondering why having this as a vector being looped through by an iterator (to get at a single object) is costing me over 200 frames when compared to it being a single pointer? The 200+ frames faster code is: std::vector<GameObject_Tile*>::iterator it; for(int y = 0; y < GAME_TILES_Y; y++) { for(int x = 0; x < GAME_TILES_X; x++) { //gameTiles[x][y].tiles is used as a pointer here instead of using *it }} tiles is: struct Game_Tile { // More specific object types will be added here eventually GameObject_Tile* tiles; };

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