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• Where to turn upon realizing I can't program my way out of a paper bag?

  - by luminarious

  I have no job and just enough money to get by until April or so. While looking for work, I figured I might as well go through with a pet project, a browser based card game. Make it nice and free, collect donations and maybe earn enough for a movie ticket to escape reality for a while. I have dabbled in web development a bit. I can make simple stuff happen with JS/PHP if I follow tutorials. I designed my own art blog's template - http://luminarious.tumblr.com. I can visualise the game working in my head, flowcharts and everything. But then I tried to go deeper with Javascript and almost had an aneurysm before understanding what a closure is. Wether I suck at learning, have ADD or fail epically at productivity, I have not got much done. Coming up with ideas, screen mock-ups and so forth was very enjoyable, but actual implementation.. not so much. In fact, I cry a bit every time I think about the time someone competent could have finished this in. I'd like to excuse myself with my ENTP personality type, but that hardly solves anything. Rather, I'd like to know to get from A (bunch of ideas with little semblance to a web app) to B (something to proudly show others) while being unable to pay anyone? Are there any secret techniques for learning? Is there any way to get mentoring or code review? Is there anyone with too much free time willing to code for me? How to trust someone to not steal my code when I ask for assistance? Is there anything I should have asked instead of any of those?

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• Dealing with large number of text strings

  - by Fadrian

  My project when it is running, will collect a large number of string text block (about 20K and largest I have seen is about 200K of them) in short span of time and store them in a relational database. Each of the string text is relatively small and the average would be about 15 short lines (about 300 characters). The current implementation is in C# (VS2008), .NET 3.5 and backend DBMS is Ms. SQL Server 2005 Performance and storage are both important concern of the project, but the priority will be performance first, then storage. I am looking for answers to these: Should I compress the text before storing them in DB? or let SQL Server worry about compacting the storage? Do you know what will be the best compression algorithm/library to use for this context that gives me the best performance? Currently I just use the standard GZip in .NET framework Do you know any best practices to deal with this? I welcome outside the box suggestions as long as it is implementable in .NET framework? (it is a big project and this requirements is only a small part of it) EDITED: I will keep adding to this to clarify points raised I don't need text indexing or searching on these text. I just need to be able to retrieve them in later stage for display as a text block using its primary key. I have a working solution implemented as above and SQL Server has no issue at all handling it. This program will run quite often and need to work with large data context so you can imagine the size will grow very rapidly hence every optimization I can do will help.

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• Is it possible to pass Calendar new date in the bean without listener?

  - by isabsent

  I am trying to pass new date from PrimeFaces p:calendar (placed in p:dataTable column) to the backing bean: <p:column > <p:calendar value="#{bean.date}">` <p:ajax /> </p:calendar> </p:column> It does not update bean.date. Variants with <p:ajax update="@this" event="change"/> <p:ajax update="@this" event="select"/> do not update bean.date too. The only way I have found is using of listener. However, I suppose, there should be a way without listener implementation like for simple facelets: <p:column> <h:inputText value="#{bean.note}" > <f:ajax/> </h:inputText> </p:column> that works fine for me. Does anybody know how to get it working!?

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• Is there a Java data structure that is effectively an ArrayList with double indicies and built-in in

  - by Bob Cross

  I am looking for a pre-built Java data structure with the following characteristics: It should look something like an ArrayList but should allow indexing via double-precision rather than integers. Note that this means that it's likely that you'll see indicies that don't line up with the original data points (i.e., asking for the value that corresponds to key "1.5"). As a consequence, the value returned will likely be interpolated. For example, if the key is 1.5, the value returned could be the average of the value at key 1.0 and the value at key 2.0. The keys will be sorted but the values are not ensured to be monotonically increasing. In fact, there's no assurance that the first derivative of the values will be continuous (making it a poor fit for certain types of splines). Freely available code only, please. For clarity, I know how to write such a thing. In fact, we already have an implementation of this and some related data structures in legacy code that I want to replace due to some performance and coding issues. What I'm trying to avoid is spending a lot of time rolling my own solution when there might already be such a thing in the JDK, Apache Commons or another standard library. Frankly, that's exactly the approach that got this legacy code into the situation that it's in right now.... Is there such a thing out there in a freely available library?

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• Determining presence of prototype with correct return type

  - by R..

  Here's a random problem in C black magic I just came up with: Write a function that returns 1 if malloc has been prototyped to return a pointer type and 0 if malloc has a return type of int (either implicitly or due to wrong prototype), without invoking any implementation-defined or undefined behavior. I believe it's solvable, but I haven't worked out the solution. Note that calling the function cannot be necessary and in fact is not possible since calling a function with the incorrect prototype is undefined behavior. I have some ideas for ingredients but I think it makes for a better puzzle (and possibly more diverse ideas) if I leave them out for now. I don't need the solution for any immediate use, but it could be handy in configure scripts and such. Update: A better example of the usefulness (with strdup instead of malloc): #undef strdup #define strdup(x) (strdup_has_proto ? strdup((x)) : my_strdup((x))) i.e. being able to implement X_has_proto as an expression at the source level could be a portable way to use functions which a system might or might not have, and fall back on a local replacement, without needing any separate configure step.

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• Serialization for memcached

  - by Ram

  I have this huge domain object(say parent) which contains other domain objects. It takes a lot of time to "create" this parent object by querying a DB (OK we are optimizing the DB). So we decided to cache it using memcached (with northscale to be specific) So I have gone through my code and marked all the classes (I think) as [Serializable], but when I add it to the cache, I see a Serialization Exception getting thrown in my VS.net output window. var cache = new NorthScaleClient("MyBucket"); cache.Store(StoreMode.Set, key, value); This is the exception: A first chance exception of type 'System.Runtime.Serialization.SerializationException' occurred in mscorlib.dll SO my guess is, I have not marked all classes as [Serializable]. I am not using any third party libraries and can mark any class as [Serializable], but how do I find out which class is failing when the cache is trying to serialize the object ? Edit1: casperOne comments make me think. I was able to cache these domain object with Microsoft Cache Application Block without marking them [Serializable], but not with NorthScale memcached. It makes me think that there might be something to do with their implementation, but just out of curiosity, am still interested in finding where it fails when trying to add the object to memcached

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• Beginner Question ; About Prime Generation in "C" - What is wrong with my code ? -

  - by alorsoncode

  I'm a third year irregular CS student and ,i just realized that i have to start coding. I passed my coding classes with lower bound grades so that i haven't a good background in coding&programming. I'm trying to write a code that generates prime numbers between given upper and lower bounds. Not knowing C well, enforce me to write a rough code then go over it to solve. I can easily set up the logic for intended function but i probably create a wrong algorithm through several different ways. Here I share my last code, i intend to calculate that when a number gives remainder Zero , it should be it self and 1 , so that count==2; What is wrong with my implementation and with my solution generating style? I hope you will warm me up to programming world, i couldn't find enough motivation and courage to get deep into programming. Thanks in Advance :) Stdio and Math.h is Included int primegen(int down,int up) { int divisor,candidate,count=0,k; for(candidate=down;candidate<=up;candidate++) { for(divisor=1;divisor<=candidate;divisor++) { k=(candidate%divisor); } if (k==0) count++; if(count==2) { printf("%d\n", candidate); count=0; } else { continue; } } } int main() { primegen(3,15); return 0; }

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• Show menu when view is long pressed

  - by swift1691

  I've been looking around on the internet regarding my question but I couldn't find a straight answer. Is it possible to create a non-blocking menu similar to the overflow menu found in Android 4.0+ when a view is long pressed? I have a number of LinearLayout instances which have an OnLongClickListener which brings up a context menu, but it's not exactly what I am looking for. I was hoping for a smoother menu which is brought up when one of these instances is clicked, and removed when the user clicks outside of the menu's region. This is very similar to the way the overflow menu behaves in the Android ActionBar. So to sum up, is it possible to replicate the look-and-fell and the behavior of the overflow menu when using context menus? Here's hoping I don't have to jump through hoops to get the implementation that I desire. Thanks in advance. EDIT: After some digging I've found the PopupMenu which is exactly what I was looking for however it works only on devices running Honeycomb and above. Does anyone know of a way with which I can replicate this menu behavior in older versions of Android without using blocking windows like dialogs?

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• What is a better, cleaner way of using List<T>

  - by Tim Meers

  I'm looking to implement a few nicer ways to use List in a couple of apps I'm working on. My current implementation looks like this. MyPage.aspx.cs protected void Page_Load(object sender, EventArgs e) { BLL.PostCollection oPost = new BLL.PostCollection(); oPost.OpenRecent(); rptPosts.DataSource = oArt; rptPosts.DataBind(); } BLL Class(s) public class Post { public int PostId { get; set; } public string PostTitle { get; set; } public string PostContent { get; set; } public string PostCreatedDate { get; set; } public void OpenRecentInitFromRow(DataRow row) { this.PostId = (int) row["id"]; this.PostTitle = (string) row["title"]; this.PostContent = (string) row["content"]; this.PostCreatedDate = (DateTime) row["createddate"]; } } public class PostCollection : List<Post> { public void OpenRecent() { DataSet ds = DbProvider.Instance().Post_ListRecent(); foreach (DataRow row in ds.Tables[0].Rows) { Post oPost = new Post(); oPost.OpenRecentInitFromRow(row); Add(oPost); } } } Now while this is working all well and good, I'm just wondering if there is any way to improve it, and just make it cleaner that having to use the two different classes do to something I think can happen in just one class or using an interface.

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• UITableView populating EVERY OTHER launch

  - by Joshmattvander

  I am having a problem that I cant seem to get to the bottom of. In my view did load code, I am creating an array and attempting to populate the table. For some reason it only populates the data on EVERY OTHER time the app is run. I put logs in viewDidLoad which runs as does viewWillAppear and outputs the correct count for the array. Also, the UITableView specicic methods get called when it works and they just don't get called when it doesnt work. I cant figure out the root of this problem. Again this occurrence happens exactly 50% of the time. Theres no dynamic data that could be tripping up or anything. #import "InfoViewController.h" @implementation InfoViewController - (void)viewDidLoad { NSLog(@"Info View Loaded"); // This runs infoList = [[NSMutableArray alloc] init]; //Set The Data //Theres 8 similar lines [infoList addObject :[[NSMutableDictionary alloc] initWithObjectsAndKeys: @"Scrubbed", @"name", @"scrubbed", @"url", nil]]; NSLog(@"%d", [infoList count]); // This shows the count correctly every time [super viewDidLoad]; } -(void) viewWillAppear:(BOOL)animated { NSLog(@"Info Will Appear"); // This Runs } - (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView { return 1; } - (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section { // This WILL NOT RUN when it doesnt work, and DOES show the count when it does run NSLog(@"Counted in numberOfRowsInSection %d", [infoList count]); return [infoList count]; } - (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath { NSLog(@"ROW"); static NSString *CellIdentifier = @"infoCell"; UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier]; if (cell == nil) { cell = [[[UITableViewCell alloc] initWithFrame:CGRectZero reuseIdentifier:CellIdentifier] autorelease]; } cell.accessoryType = UITableViewCellAccessoryDisclosureIndicator; cell.textLabel.text = [[infoList objectAtIndex:indexPath.row] objectForKey:@"name"]; return cell; } @end

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• Using SimpleDB (with SimpleSavant) with POCO / existing entities, not attributes on my classes

  - by alex

  I'm trying to use Simple Savant within my application, to use SimpleDB I currently have (for example) public class Person { public Guid Id { get; set; } public string Name { get; set; } public string Description { get; set; } public DateTime DateOfBirth { get; set; } } To use this with Simple Savant, i'd have to put attributes above the class declaration, and property - [DomainName("Person")] above the class, and [ItemName] above the Id property. I have all my entities in a seperate assembly. I also have my Data access classes an a seperate assembly, and a class factory selects, based on config, the IRepository (in this case, IRepository I want to be able to use my existing simple class - without having attributes on the properties etc.. In case I switch out of simple db, to something else - then I only need to create a different implementation of IRepository. Should I create a "DTO" type class to map the two together? Is there a better way?

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• Need help configuring Castle-Windsor

  - by Jonathas Costa

  I have these base interfaces and providers in one assembly (Assembly1): public interface IEntity { } public interface IDao { } public interface IReadDao<T> : IDao where T : IEntity { IEnumerable<T> GetAll(); } public class NHibernate<T> : IReadDao<T> where T : IEntity { public IEnumerable<T> GetAll() { return new List<T>(); } } And I have this implementation inside another assembly (Assembly2): public class Product : IEntity { public string Code { get; set; } } public interface IProductDao : IReadDao<Product> { IEnumerable<Product> GetByCode(string code); } public class ProductDao : NHibernate<Product>, IProductDao { public IEnumerable<Product> GetByCode(string code) { return new List<Product>(); } } I want to be able to get IRead<Product> and IProductDao from the container. I am using this registration: container.Register( AllTypes.FromAssemblyNamed("Assembly2") .BasedOn(typeof(IReadDao<>)).WithService.FromInterface(), AllTypes.FromAssemblyNamed("Assembly1") .BasedOn(typeof(IReadDao<>)).WithService.Base()); The IReadDao<Product> works great. The container gives me ProductDao. But if I try to get IProductDao, the container throws ComponentNotFoundException. How can I correctly configure the registration?

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• Is there a Python module for handling Python object addresses?

  - by cool-RR

  (When I say "object address", I mean the string that you type in Python to access an object. For example 'life.State.step'. Most of the time, all the objects before the last dot will be packages/modules, but in some cases they can be classes or other objects.) In my Python project I often have the need to play around with object addresses. Some tasks that I have to do: Given an object, get its address. Given an address, get the object, importing any needed modules on the way. Shorten an object's address by getting rid of redundant intermediate modules. (For example, 'life.life.State.step' may be the official address of an object, but if 'life.State.step' points at the same object, I'd want to use it instead because it's shorter.) Shorten an object's address by "rooting" a specified module. (For example, 'garlicsim_lib.simpacks.prisoner.prisoner.State.step' may be the official address of an object, but I assume that the user knows where the prisoner package is, so I'd want to use 'prisoner.prisoner.State.step' as the address.) Is there a module/framework that handles things like that? I wrote a few utility modules to do these things, but if someone has already written a more mature module that does this, I'd prefer to use that. One note: Please, don't try to show me a quick implementation of these things. It's more complicated than it seems, there are plenty of gotchas, and any quick-n-dirty code will probably fail for many important cases. These kind of tasks call for battle-tested code. UPDATE: When I say "object", I mostly mean classes, modules, functions, methods, stuff like these. Sorry for not making this clear before.

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• passing info from facebook to UITabBarController

  - by EquinoX

  When my app first start, it shows up a main page showing to login to facebook and then it goes to the UITabBarController. The code that I have in my app delegate is the following: //this is the .h @interface NMeAppDelegate : NSObject <UIApplicationDelegate> { UIWindow *window; MainViewController *controller; UITabBarController *tabBar; } @property (nonatomic, retain) IBOutlet UITabBarController *tabBar; @property (nonatomic, retain) MainViewController *controller; @property (nonatomic, retain) IBOutlet UIWindow *window; @end //this is the .m of the app delegate #import "NMeAppDelegate.h" @implementation NMeAppDelegate @synthesize window; @synthesize tabBar; @synthesize controller; #pragma mark - #pragma mark Application lifecycle - (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions { // Override point for customization after application launch. controller = [[MainViewController alloc] init]; [window addSubview:tabBar.view]; [window addSubview:controller.view]; [window makeKeyAndVisible]; return YES; } Inside of MainViewController, I actually have a Facebook * facebook object, which basically has all of the information that I need. Every information that I need for this apps is queried in the MainViewController. The problem is that after getting this info and now I am in the UITabViewController... how do I get those information that I already queried facebook for? I have a class called UserInfo as well, which basically has everything essential I need. I need to have the info from UserInfo so that the other ViewController in the UITabBarController have access to it.... I hope my question makes sense

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• Need help implementing this algorithm with map reduce(hadoop)

  - by Julia

  Hi all! i have algorithm that will go through a large data set read some text files and search for specific terms in those lines. I have it implemented in Java, but I didnt want to post code so that it doesnt look i am searching for someone to implement it for me, but it is true i really need a lot of help!!! This was not planned for my project, but data set turned out to be huge, so teacher told me I have to do it like this. I was reading about MapReduce and thaught that i first do the standard implementation and then it will be more/less easier to do it with mapreduce. But didnt happen, since algorithm is quite stupid and nothing special, and map reduce...i cant wrap my mind around it. So here is shortly pseudo code of my algorithm LIST termList (there is method that creates this list from lucene index) FOLDER topFolder INPUT topFolder IF it is folder and not empty list files (there are 30 sub folders inside) FOR EACH sub folder GET file "CheckedFile.txt" analyze(CheckedFile) ENDFOR END IF Method ANALYZE(CheckedFile) read CheckedFile WHILE CheckedFile has next line GET line FOR(loops through termList) GET third word from line IF third word = term from list append whole line to string buffer ENDIF ENDFOR END WHILE OUTPUT string buffer to file Also, as you can see, each time when "analyze" is called, new file has to be created, i understood that map reduce is difficult to write to many outputs??? I understand mapreduce intuition, and my example seems perfectly suited for mapreduce, but when it comes to do this, obviously I do not know enough and i am STUCK! Please please help.

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• Boost shared_ptr use_count function

  - by photo_tom

  My application problem is the following - I have a large structure foo. Because these are large and for memory management reasons, we do not wish to delete them when processing on the data is complete. We are storing them in std::vector<boost::shared_ptr<foo>>. My question is related to knowing when all processing is complete. First decision is that we do not want any of the other application code to mark a complete flag in the structure because there are multiple execution paths in the program and we cannot predict which one is the last. So in our implementation, once processing is complete, we delete all copies of boost::shared_ptr<foo>> except for the one in the vector. This will drop the reference counter in the shared_ptr to 1. Is it practical to use shared_ptr.use_count() to see if it is equal to 1 to know when all other parts of my app are done with the data. One additional reason I'm asking the question is that the boost documentation on the shared pointer shared_ptr recommends not using "use_count" for production code.

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• javascript var assignment conversion to target type

  - by pbhd

  searching for a function, which converts rhs to the type of lhs. e.g. var x=false // x is boolean now; x=assign (x, "true"); //should convert "true" to boolean and return that x=assign (x, 1); // dto, convert 1 to true x=0 // x is number x=assign (x, "123"); // should convert "123" to 123; so such a function can be written, thats not the question. But: Is there somewhere a somehow complete implementation of such a thing? I started with something like that: function assign (v, x) { if (typeof v==typeof x) { return x; } switch (typeof v) { case 'boolean' : { return x=='true'?true:false; } case 'number' : { return parseFloat(x); } } return "xxx"; } var v=true; var x='true'; var r1=assign (v, x); console.log (typeof r1+ " "+r1); v=10; x="123"; var r1=assign (v, x); console.log (typeof r1+ " "+r1); which of course is not complete, but maybe shows what I'm goig for.

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• Can't see anything wrong with simple code

  - by melee

  Here is my implementation file: using namespace std; #include <iostream> #include <iomanip> #include <string> #include <stack> //line 5 #include "proj05.canvas.h" //----------------Constructor----------------// Canvas::Canvas() //line 10 { Title = ""; Nrow = 0; Ncol = 0; image[][]; // line 15 PixelCoordinates.r = 0; PixelCoordinates.c = 0; } //-------------------Paint------------------// line 20 void Canvas::Paint(int R, int C, char Color) { cout << "Paint to be implemented" << endl; } The errors I'm getting are these: proj05.canvas.cpp: In function 'std::istream& operator>>(std::istream&, Canvas&)': proj05.canvas.cpp:11: error: expected `;' before '{' token proj05.canvas.cpp:22: error: a function-definition is not allowed here before '{' token proj05.canvas.cpp:24: error: expected `}' at end of input proj05.canvas.cpp:24: error: expected `}' at end of input These seem like simple syntax errors, but I am not sure what's wrong. Could someone decode these for me? I'd really appreciate it, thanks for your time!

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• Why my oracleParameter doesnt work?

  - by user1824356

  I'm a .NET developer and this is the first time i work with oracle provider (Oracle 10g and Framework 4.0). When i add parameter to my command in this way: objCommand.Parameters.Add("pc_cod_id", OracleType.VarChar, 4000).Value = codId; objCommand.Parameters.Add("pc_num_id", OracleType.VarChar, 4000).Value = numId; objCommand.Parameters.Add("return_value", OracleType.Number).Direction = ParameterDirection.ReturnValue; objCommand.Parameters.Add("pc_email", OracleType.VarChar, 4000).Direction = ParameterDirection.Output; I have no problem with the result. But when a add parameter in this way: objCommand.Parameters.Add(CreateParameter(PC_COD_ID, OracleType.VarChar, codId, ParameterDirection.Input)); objCommand.Parameters.Add(CreateParameter(PC_NUM_ID, OracleType.VarChar, numId, ParameterDirection.Input)); objCommand.Parameters.Add(CreateParameter(RETURN_VALUE, OracleType.Number, ParameterDirection.ReturnValue)); objCommand.Parameters.Add(CreateParameter(PC_EMAIL, OracleType.VarChar, ParameterDirection.Output)); The implementation of that function is: protected OracleParameter CreateParameter(string name, OracleType type, ParameterDirection direction) { OracleParameter objParametro = new OracleParameter(name, type); objParametro.Direction = direction; if (type== OracleType.VarChar) { objParametro.Size = 4000; } return objParametro; } All my result are a empty string. My question is, these way to add parameters are not the same? And if no, what is the difference? Thanks :) Add: Sorry i forgot mention "CreateParameter" is a function with multiple implementations the base is the above function, the other use that. protected OracleParameter CreateParameter(string name, OracleType type, object value, ParameterDirection direction) { OracleParameter objParametro = CreateParameter(name, type, value); objParametro.Direction = direction; return objParametro; } The last parameters doesn't need value because those are output parameter, those bring me data from the database.

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• Considering moving from Java/Spring MVC to Grails

  - by MDS

  I'm currently using Java & Spring (MVC) to create a webapp, and I'm considering moving to Grails. I'd appreciate feedback/insight on the following: I have multiple application contexts in the current Java/Spring webapp that I load through the web.xml ContextLoaderListener; is it possible to have multiple application contexts in Grails? If, yes, how? This webapp extensively uses a CXF restful web service and the current Java/Spring webapp uses the bundled CXF HTTP client. Can I continue to use the (Java) CXF HTTP Client in Grails? I implemented Spring Security using a custom implementation of UserDetails and UserDetailsService, can I re-use these implementations in Grails "as is" or must I re-implement them? There is an instance where I've relied on Spring's jdbc template (rather than the available ORM) and an additional data source I defined in app context, can I re-use this in Grails? I plan on using Maven as the project management tool; are there any issues of using Maven with Grails where there is a combination of groovy and java?

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• PHP - Patterns within Arrays

  - by Toby

  I am trying to create a function which maps a recurring pattern of integers using an array. As an example if I have a starting array of (0,1,3) and I know that I want to stop the pattern when I hit 15. The pattern gets incremented by a fixed integer each time (lets say 4) so my final pattern should be.. 0 1 3 4 (0 + 4) 5 (1 + 4) 7 (2 + 4) 8 (4 + 4) 9 (5 + 4) 11(7 + 4) 12(8 + 4) 13(9 + 4) 15(11+ 4) Does anyone have any pointers on how this can be achieved? My current implementation works but is stupidly inefficient which something like this... $array = array(0,1,3); $inc = 4; $end = end($array); $final = 15; while($end < $final) { $tmp = array(); foreach($array AS $row) { $tmp = $row + $inc; } $array = merge($tmp, $array); $end = end($array); }

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• What to throw in a C++ class wrapping a C library ?

  - by ereOn

  I have to create a set of wrapping C++ classes around an existing C library. For many objects of the C library, the construction is done by calling something like britney_spears* create_britney_spears() and the opposite function void free_britney_spears(britney_spears* brit). If the allocation of a britney_spears fails, create_britney_spears() returns NULL. This is, as far as I know, a very common pattern. Now I want to wrap this inside a C++ class. //britney_spears.hpp class BritneySpears { public: BritneySpears(); private: boost::shared_ptr<britney_spears> m_britney_spears; }; And here is the implementation: // britney_spears.cpp BritneySpears::BritneySpears() : m_britney_spears(create_britney_spears(), free_britney_spears) { if (!m_britney_spears) { // Here I should throw something to abort the construction, but what ??! } } So the question is in the code sample: What should I throw to abort the constructor ? I know I can throw almost anything, but I want to know what is usually done. I have no other information about why the allocation failed. Should I create my own exception class ? Is there a std exception for such cases ? Many thanks.

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• Implementing comparision operators via 'tuple' and 'tie', a good idea?

  - by Xeo

  (Note: tuple and tie can be taken from Boost or C++11.) When writing small structs with only two elements, I sometimes tend to choose a std::pair, as all important stuff is already done for that datatype, like operator< for strict-weak-ordering. The downsides though are the pretty much useless variable names. Even if I myself created that typedef, I won't remember 2 days later what first and what second exactly was, especially if they are both of the same type. This gets even worse for more than two members, as nesting pairs pretty much sucks. The other option for that is a tuple, either from Boost or C++11, but that doesn't really look any nicer and clearer. So I go back to writing the structs myself, including any needed comparision operators. Since especially the operator< can be quite cumbersome, I thought of circumventing this whole mess by just relying on the operations defined for tuple: Example of operator<, e.g. for strict-weak-ordering: bool operator<(MyStruct const& lhs, MyStruct const& rhs){ return std::tie(lhs.one_member, lhs.another, lhs.yet_more) < std::tie(rhs.one_member, rhs.another, rhs.yet_more); } (tie makes a tuple of T& references from the passed arguments.) Edit: The suggestion from @DeadMG to privately inherit from tuple isn't a bad one, but it got quite some drawbacks: If the operators are free-standing (possibly friends), I need to inherit publicly With casting, my functions / operators (operator= specifically) can be easily bypassed With the tie solution, I can leave out certain members if they don't matter for the ordering Are there any drawbacks in this implementation that I need to consider?

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• Good C string libary

  - by chamakits

  Hello all. I recently got inspired to start up a project I've been wanting to code for a while. I want to do it in C, because memory handling is key this application. I was searching around for a good implementation of strings in C, since I know me doing it myself could lead to some messy buffer overflows, and I expect to be dealing with a fairly big amount of strings. I found this article which gives details on each, but they each seem like they have a good amount of cons going for them (don't get me wrong, this article is EXTREMELY helpful, but it still worries me that even if I were to choose one of those, I wouldn't be using the best I can get). I also don't know how up to date the article is, hence my current plea. What I'm looking for is something that may hold a large amount of characters, and simplifies the process of searching through the string. If it allows me to tokenize the string in any way, even better. Also, it should have some pretty good I/O performance. Printing, and formatted printing isn't quite a top priority. I know I shouldn't expect a library to do all the work for me, but was just wandering if there was a well documented string function out there that could save me some time and some work. Any help is greatly appreciated. Thanks in advance! EDIT: I was asked about the license I prefer. Any sort of open source license will do, but preferably GPL (v2 or v3). EDIt2: I found betterString (bstring) library and it looks pretty good. Good documentation, small yet versatile amount of functions, and easy to mix with c strings. Anyone have any good or bad stories about it? The only downside I've read about it is that it lacks Unicode (again, read about this, haven't seen it face to face just yet), but everything else seems pretty good. EDIT3: Also, preferable that its pure C.

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• Is `super` local variable?

  - by Michael

  // A : Parent @implementation A -(id) init { // change self here then return it } @end A A *a = [[A alloc] init]; a. Just wondering, if self is a local variable or global? If it's local then what is the point of self = [super init] in init? I can successfully define some local variable and use like this, why would I need to assign it to self. -(id) init { id tmp = [super init]; if(tmp != nil) { //do stuff } return tmp; } b. If [super init] returns some other object instance and I have to overwrite self then I will not be able to access A's methods any more, since it will be completely new object? Am I right? c. super and self pointing to the same memory and the major difference between them is method lookup order. Am I right? sorry, don't have Mac to try, learning theory as for now...

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