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  • Custom class deallocated as soon as the app starts.

    - by Tangrs
    Heya, I've added a class object to the nib file. All connections are made. But for some reason, the object is deallocated as soon as it's created. Here's the code: control.h: #import <Foundation/Foundation.h> @interface control : NSObject { IBOutlet UILabel *PlayerScore; } -(IBAction) addPoint: sender; -(void) dealloc; @end control.m: #import "control.h" @implementation control -(IBAction)addPoint: sender { NSLog(@"Ohhai. Didn't crash."); //Doesn't even make it to this stage. int i = [PlayerScore.text intValue]; PlayerScore.text=[NSString stringWithFormat: @"%d",++i]; } -(void) dealloc { NSLog(@"ZOMGWTF?"); [super dealloc]; } @end Here is the console log: [Session started at 2010-06-09 19:47:57 +1000.] 2010-06-09 19:47:58.771 App[91100:207] ZOMGWTF? And after I click the button which messages addPoint, of course, it crashes. 2010-06-09 19:47:59.703 App[91100:207] * -[control] performSelector:withObject:withObject:]: message sent to deallocated instance 0x3843d80 Does anyone have any ideas?

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  • guarantee child records either in one table or another, but not both?

    - by user151841
    I have a table with two child tables. For each record in the parent table, I want one and only one record in one of the child tables -- not one in each, not none. How to I define that? Here's the backstory. Feel free to criticize this implementation, but please answer the question above, because this isn't the only time I've encountered it: I have a database that holds data pertaining to user surveys. It was originally designed with one authentication method for starting a survey. Since then, requirements have changed, and now there are two different ways someone could sign on to start a survey. Originally I captured the authentication token in a column in the survey table. Since requirements changed, there are three other bits of data that I want to capture in authentication. So for each record in the survey table, I'm either going to have one token, or a set of three. All four of these are of different types, so my thought was, instead of having four columns where either one is going to be null, or three are going to be null ( or even worse, a bad mashup of either of those scenarios ), I would have two child tables, one for holding the single authentication token, the other for holding the three. Problem is, I don't know offhand how to define that in DDL. I'm using MySQL, so maybe there's a feature that MySQL doesn't implement that lets me do this.

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  • Can't give my custom prototype cells in tableview different heights

    - by kerbelda
    I've looked around at other questions here and many other sources online and just can't find a solution. I have 3 rows and no matter what I do, they all keep the width defined in the tableview. The first one is what I want, but the second and 3rd I can't give a custom height. Below is my code: #import "DetailTableViewController.h" #import "EventDetailTableViewCell.h" #import "EventDescriptionTableViewCell.h" #import "EventMapTableViewCell.h" @interface DetailTableViewController () @end @implementation DetailTableViewController - (void)viewDidLoad { [super viewDidLoad]; } #pragma mark - Table view data source - (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView { // Return the number of sections. return 3; } - (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section { // Return the number of rows in the section. return 1; } - (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath { if (indexPath.section == 0) { static NSString *CellIdentifier = @"headerCell"; EventDetailTableViewCell *headerCell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier forIndexPath:indexPath]; headerCell.headerImage.image = [UIImage imageNamed:@"img4.png"]; return headerCell; } else if (indexPath.section == 1) { static NSString *CellIdentifier = @"descriptionCell"; EventDescriptionTableViewCell *descriptionCell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier forIndexPath:indexPath]; descriptionCell.descriptionImage.image = [UIImage imageNamed:@"img2.png"]; return descriptionCell; } else { static NSString *CellIdentifier = @"mapCell"; EventMapTableViewCell *mapCell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier forIndexPath:indexPath]; return mapCell; } } #pragma mark - Helper Methods - (NSString *)tableView:(UITableView *)tableView titleForHeaderInSection:(NSInteger)section { if (section == 1) { return @" "; } else if (section == 2) { return @" "; } else { return nil; } } -(CGFloat)tableView:(UITableView *)tableView heightForRowAtIndexPath:(NSIndexPath *)indexPath { if (indexPath.row == 0) { return 222; } else if (indexPath.row == 1) { return 80; } else { return 100; } } @end

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  • How i pass my view to nib at run time(Dynamically) in viewController class?

    - by Rajendra Bhole
    Hi, I want to create viewController class programmatically in which the view of nib file of viewController is not fixed. I have a UntitledViewController class that contains 4 UIButtons: -(IBAction)buttonPressed:(id)sender{ if((UIButton *)sender == button1){ tagNumber = button1.tag; NewViewController *newVC = [[NewViewController alloc] init]; //newVC.tagN [self.navigationController pushViewController:newVC animated:YES]; NSLog(@"Button Tag Number:- %i", tagNumber); } if((UIButton *) sender == button2){ tagNumber = button2.tag; NewViewController *newVC = [[NewViewController alloc] init]; [self.navigationController pushViewController:newVC animated:YES]; } if((UIButton *) sender == button3){ tagNumber = button3.tag; NewViewController *newVC = [[NewViewController alloc] init]; [self.navigationController pushViewController:newVC animated:YES]; } if((UIButton *) sender == button4){ int x = tagNumber; tagNumber = button4.tag; NewViewController *newVC = [[NewViewController alloc] init]; newVC.untitledVC = self; [self.navigationController pushViewController:newVC animated:YES]; } } When I will click any one of the UIButtons, I want to create a new NewViewController class with button tag property but without fixed nib file. In NewViewController's loadView event I want to fix the view of the nib of NewViewController class using UIButton's tag property (In NewViewController.xib I'm creating 4 UIViews named view1, view2, view3 and view4). -(void)loadView{ [super loadView]; CGRect frame = CGRectMake(0, 0, 320, 480); UIView *newView = [[UIView alloc] initWithFrame:frame]; newView.tag = untitledVC.tagNumber; self.view1 = newView; } Now I want that when I click button1 the NewViewController will be generated with view1 and when I click button2 the NewViewController will be generated with view2 and so on with different implementation. Thanks.

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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 are good ways to implement search and search results using ajax?

    - by Amr ElGarhy
    i have some text box in a page and in the same page there will be a table 'grid' like for holding the search result. When the user start editing and of the textbox above, the search must start by sending all textboxs values to the server 'ajax', and get back with the results to fill the below grid. Notes: This grid should support paging, sorting by clicking on headers and it will contains some controls beside the results such as checkboxs for boolean values and links for opening details in another page. I know many ways to do this some of them are: 1- updatepanel around all of these controls and thats it "fast dirty solution" 2- send the search criteria using ajax request using JQuery post function for example and get back the JSON result, and using a template will draw the grid "clean but will take time to finish and will be harder to edit later". 3- .... My question is: What do you think will be the best choice to implement this scenario? because i face this scenario too much, and want to know which implementation will be better regarding performance, optimization, and time to finish. I just want to know your thoughts about this issue.

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  • Make All Types Constant by Default in C++

    - by Jon Purdy
    What is the simplest and least obtrusive way to indicate to the compiler, whether by means of compiler options, #defines, typedefs, or templates, that every time I say T, I really mean T const? I would prefer not to make use of an external preprocessor. Since I don't use the mutable keyword, that would be acceptable to repurpose to indicate mutable state. Potential (suboptimal) solutions so far: // I presume redefinition of keywords is implementation-defined or illegal. #define int int const #define ptr * const int i(0); int ptr j(&i); typedef int const Int; typedef int const* const Intp; Int i(0); Intp j(&i); template<class T> struct C { typedef T const type; typedef T const* const ptr; }; C<int>::type i(0); C<int>::ptr j(&i);

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  • Generic delegate instances

    - by Luc C
    I wonder if C# (or the underlying .NET framework) supports some kind of "generic delegate instances": that is a delegate instance that still has an unresolved type parameter, to be resolved at the time the delegate is invoked (not at the time the delegate is created). I suspect this isn't possible, but I'm asking it anyway... Here is an example of what I'd like to do, with some "???" inserted in places where the C# syntax seems to be unavailable for what I want. (Obviously this code doesn't compile) class Foo { public T Factory<T>(string name) { // implementation omitted } } class Test { public void TestMethod() { Foo foo = new Foo(); ??? magic = foo.Factory; // No type argument given here yet to Factory! // What would the '???' be here (other than 'var' :) )? string aString = magic<string>("name 1"); // type provided on call int anInt = magic<int>("name 2"); // another type provided on another call // Note the underlying calls work perfectly fine, these work, but i'd like to expose // the generic method as a delegate. string aString2 = foo.Factory<string>("name 1"); int anInt2 = foo.Factory<int>("name 2"); } } Is there a way to actually do something like this in C#? If not, is that a limitation in the language, or is it in the .NET framework?

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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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  • Retrieve E-mail from server (pop3) by date for filtering on subject or body in C#

    - by Josh
    I have a piece of monitoring software I am writing which needs to retrieve e-mails sent to an address for a certain day so that I can filter them by a regex in the subject or body. I don't need to retrieve the entire message, only the subject and body for all messages on a given day so that I can evaluate them with a regular expression for a token. I looked at EAGetMail as a solution, but their implementation doesn't do what I need to to do. I can only get all information on mail, which only has the size and index. I would need it by subject, but even then I don't want to get everything in inbox. If I went with this solution I have to get all mail, and then retrieve each mail message individually to evaluate the subject and body. This is not ideal. I also looked at OpenPop.Net, but it too does not have a targeted retrieval for today's messages only. Can I even do what I want without looping through every single email on the server until I find a match? What is the best way to accomplish what I am trying to do? Am I going to have to build a custom web request to get the data I want? Also, I looked at Chilkat, but I am looking for a free solution, even if it means building the http request myself.

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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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  • Why do I have memory problems?

    - by Tattat
    I got this error from XCode: objc[8422]: FREED(id): message release sent to freed object=0x3b120c0 I googled and find that is related to the memory. But I don't know which line of code I go wrong, any ideas? After I launch my app in simulator, it prompts a second, than, no other error except the error above. @implementation MyAppDelegate @synthesize window; @synthesize viewController; - (void)applicationDidFinishLaunching:(UIApplication *)application { // Override point for customization after app launch [window addSubview:viewController.view]; [window makeKeyAndVisible]; [self changeScene:[MainGameMenuScene class]]; } - (void)dealloc { [viewController release]; [window release]; [super dealloc]; } - (void) changeScene: (Class) scene { BOOL animateTransition = true; if(animateTransition){ [UIView beginAnimations:nil context:NULL]; [UIView setAnimationDuration:0.5]; [UIView setAnimationTransition:UIViewAnimationTransitionFlipFromLeft forView:window cache:YES]; //does nothing without this line. } if( viewController.view != nil ) { [viewController.view removeFromSuperview]; //remove view from window's subviews. [viewController.view release]; //release gamestate } viewController.view = [[scene alloc] initWithFrame:CGRectMake(0, 0, IPHONE_WIDTH, IPHONE_HEIGHT) andManager:self]; //now set our view as visible [window addSubview:viewController.view]; [window makeKeyAndVisible]; if(animateTransition){ [UIView commitAnimations]; } }

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  • MVC design pattern in complex iPad app: is one fat controller acceptable?

    - by nutsmuggler
    I am building a complex iPad application; think of it as a scrapbook. For the purpose of this question, let's consider a page with two images over it. My main view displays my doc data rendered as a single UIImage; this because I need to do some global manipulation over them. This is my DisplayView. When editing I need to instantiate an EditorView with my two images as subviews; this way I can interact with a single image, (rotate it, scale it, move it). When editing is triggered, I hide my DisplayView and show my EditorView. In a iPhone app, I'd associate each main view (that is, a view filling the screen) to a view controller. The problem is here there is just one view controller; I've considered passing the EditorView via a modal view controller, but it's not an option (there a complex layout with a mask covering everything and palettes over it; rebuilding it in the EditorView would create duplicate code). Presently the EditorView incorporates some logic (loads data from the model, invokes some subviews for fine editing, saves data back to the model); EditorView subviews also incorporate some logic (I manipulate images and pass them back to the main EditorView). I feel this logic belongs more to a controller. On the other hand, I am not sure making my only view controller so fat a good idea. What is the best, cocoa-ish implementation of such a class structure? Feel free to ask for clarifications. Cheers.

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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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  • XNA, C# - Check if a Vector2 path crosses another Vector2 path.

    - by Nick
    Hello all, I have an XNA question for those with more experience in these matters than myself (maths). Background: I have a game that implements a boundary class, this simply hosts 2 Vector2 objects, a start and an end point. The current implementation crudely handles collision detection by assuming boundaries are always vertical or horizontal, i.e. if start.x and end.x are the same check I am not trying to pass x etc. Ideally what I would like to implement is a method that accepts two Vector2 parameters. The first being a current location, the second being a requested location (where I would like to move it to assuming no objections). The method would also accept a boundary object. What the method should then do is tell me if I am going to cross the boundry in this move. this could be a bool or ideally something representing how far I can actually move. This empty method might explain better than I can in words. /// <summary> /// Checks the move. /// </summary> /// <param name="current">The current.</param> /// <param name="requested">The requested.</param> /// <param name="boundry">The boundry.</param> /// <returns></returns> public bool CheckMove(Vector2 current, Vector2 requested, Boundry boundry) { //return a bool that indicated if the suggested move will cross the boundry. return true; }

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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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  • Slowing process creation under Java?

    - by oconnor0
    I have a single, large heap (up to 240GB, though in the 20-40GB range for most of this phase of execution) JVM [1] running under Linux [2] on a server with 24 cores. We have tens of thousands of objects that have to be processed by an external executable & then load the data created by those executables back into the JVM. Each executable produces about half a megabyte of data (on disk) that when read right in, after the process finishes, is, of course, larger. Our first implementation was to have each executable handle only a single object. This involved the spawning of twice as many executables as we had objects (since we called a shell script that called the executable). Our CPU utilization would start off high, but not necessarily 100%, and slowly worsen. As we began measuring to see what was happening we noticed that the process creation time [3] continually slows. While starting at sub-second times it would eventually grow to take a minute or more. The actual processing done by the executable usually takes less than 10 seconds. Next we changed the executable to take a list of objects to process in an attempt to reduce the number of processes created. With batch sizes of a few hundred (~1% of our current sample size), the process creation times start out around 2 seconds & grow to around 5-6 seconds. Basically, why is it taking so long to create these processes as execution continues? [1] Oracle JDK 1.6.0_22 [2] Red Hat Enterprise Linux Advanced Platform 5.3, Linux kernel 2.6.18-194.26.1.el5 #1 SMP [3] Creation of the ProcessBuilder object, redirecting the error stream, and starting it.

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  • Store data in tableview to NSUserDefaults

    - by Jozef Vrana
    Tricks.h file #import "Tricks.h" @implementation Tricks static NSMutableArray *trickList = nil; +(NSMutableArray *)trickList { if(!trickList){ trickList = [[NSMutableArray alloc]init]; } return trickList; } @end Tricks.m file @interface Tricks : NSObject @property(strong, nonatomic) NSString *trickName; Method for adding objects to array -(IBAction)saveAction:(id)sender { Tricks *trick = [[Tricks alloc]init]; trick.trickName = self.trickLabel.text; [[Tricks trickList]insertObject:trick atIndex:0]; [self.navigationController popViewControllerAnimated:YES]; } In .h file of UITabelview class I am making a reference to tricks class, but I am sure there is error on this line. @property (strong, nonatomic) Tricks *tricks; In cellForRow method I am storing data _trick = [[NSMutableDictionary alloc]initWithObjectsAndKeys:trick,nil]; NSUserDefaults *defaults=[NSUserDefaults standardUserDefaults]; [defaults setObject:_trick forKey:@"numberArray"]; [defaults synchronize]; NSLog(@"%@",_trick); In .m class of UITableview in viewDidLoad I want to retrieve data if([[NSUserDefaults standardUserDefaults] objectForKey:@"numberArray"] != nil) { _tricks = [[NSUserDefaults standardUserDefaults] objectForKey:@"numberArray"]; } Thanks for advices

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  • java class that simulates a simple database table

    - by ericso
    I have a collection of heterogenous data that I pull from a database table mtable. Then, for every unique value uv in column A, I compute a function of (SELECT * FROM mtable WHERE A=uv). Then I do the same for column B, and column C. There are rather a lot of unique values, so I don't want to hit the db repeatedly - I would rather have a class that replicates some of the functionality (most importantly some version of SELECT WHERE). Additionally, I would like to abstract the column names away from the class definition, if that makes any sense - the constructor should take a list of names as a parameter, and also, I suppose, a list of types (right now this is just a String[], which seems hacky). I'm getting the initial data from a RowSet. I've more or less done this by using a hashmap that maps Strings to lists/arrays of Objects, but I keep getting bogged down in comparisons and types, and am thinking that my current implementation really isn't as clean and clear as it could be. I'm pretty new to java, also, and am not sure if I'm not going down a completely incorrect path. Does anyone have any suggestions?

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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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  • Using overloaded operator== in a generic function

    - by Dimitri C.
    Consider the following code: class CustomClass { public CustomClass(string value) { m_value = value; } public static bool operator==(CustomClass a, CustomClass b) { return a.m_value == b.m_value; } public static bool operator!=(CustomClass a, CustomClass b) { return a.m_value != b.m_value; } public override bool Equals(object o) { return m_value == (o as CustomClass).m_value; } public override int GetHashCode() { return 0; /* not needed */ } string m_value; } class G { public static bool enericFunction1<T>(T a1, T a2) where T : class { return a1.Equals(a2); } public static bool enericFunction2<T>(T a1, T a2) where T : class { return a1==a2; } } Now when I call both generic functions, one succeeds and one fails: var a = new CustomClass("same value"); var b = new CustomClass("same value"); Debug.Assert(G.enericFunction1(a, b)); // Succeeds Debug.Assert(G.enericFunction2(a, b)); // Fails Apparently, G.enericFunction2 executes the default operator== implementation instead of my override. Can anybody explain why this happens?

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  • FileInput Help/Advice

    - by user559142
    I have a fileinput class. It has a string parameter in the constructor to load the filename supplied. However it just exits if the file doesn't exist. I would like it to output a message if the file doesn't exist - but not sure how.... Here is the class: public class FileInput extends Input { /** * Construct <code>FileInput</code> object given a file name. */ public FileInput(final String fileName) { try { scanner = new Scanner(new FileInputStream(fileName)); } catch (FileNotFoundException e) { System.err.println("File " + fileName + " could not be found."); System.exit(1); } } /** * Construct <code>FileInput</code> object given a file name. */ public FileInput(final FileInputStream fileStream) { super(fileStream); } } And its implementation: private void loadFamilyTree() { out.print("Enter file name: "); String fileName = in.nextLine(); FileInput input = new FileInput(fileName); family.load(input); input.close(); }

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  • Can AutoMapper create a map for an interface and then map with a derived type?

    - by TheCloudlessSky
    I have an interface IFoo: public interface IFoo { int Id { get; set; } } And then a concrete implementation: public class Bar : IFoo { public int Id { get; set; } public string A { get; set; } } public class Baz : IFoo { public int Id { get; set; } public string B { get; set; } } I'd like to be able to map all IFoo but specifying their derived type instead: Mapper.CreateMap<int, IFoo>().AfterMap((id, foo) => foo.Id = id); And then map (without explicitly creating maps for Bar and Baz): var bar = Mapper.Map<int, Bar>(123); // bar.Id == 123 var baz = Mapper.Map<int, Baz>(456); // baz.Id == 456 But this doesn't work in 1.1. I know I could specify all Bar and Baz but if there are 20 of these, I'd like to not have to manage them and rather just have what I did above for creating the map. Is this possible?

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  • Multiple locking task (threading)

    - by Archeg
    I need to implement the class that should perform locking mechanism in our framework. We have several threads and they are numbered 0,1,2,3.... We have a static class called ResourceHandler, that should lock these threads on given objects. The requirement is that n Lock() invokes should be realeased by m Release() invokes, where n = [0..] and m = [0..]. So no matter how many locks was performed on single object, only one Release call is enough to unlock all. Even further if o object is not locked, Release call should perform nothing. Also we need to know what objects are locked on what threads. I have this implementation: public class ResourceHandler { private readonly Dictionary<int, List<object>> _locks = new Dictionary<int, List<object>>(); public static ResourceHandler Instance {/* Singleton */} public virtual void Lock(int threadNumber, object obj) { Monitor.Enter(obj); if (!_locks.ContainsKey(threadNumber)) {_locks.Add(new List<object>());} _locks[threadNumber].Add(obj); } public virtual void Release(int threadNumber, object obj) { // Check whether we have threadN in _lock and skip if not var count = _locks[threadNumber].Count(x => x == obj); _locks[threadNumber].RemoveAll(x => x == obj); for (int i=0; i<count; i++) { Monitor.Exit(obj); } } // ..... } Actually what I am worried here about is thread-safety. I'm actually not sure, is it thread-safe or not, and it's a real pain to fix that. Am I doing the task correctly and how can I ensure that this is thread-safe?

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  • Abstract away a compound identity value for use in business logic?

    - by John K
    While separating business logic and data access logic into two different assemblies, I want to abstract away the concept of identity so that the business logic deals with one consistent identity without having to understand its actual representation in the data source. I've been calling this a compound identity abstraction. Data sources in this project are swappable and various and the business logic shouldn't care which data source is currently in use. The identity is the toughest part because its implementation can change per kind of data source, whereas other fields like name, address, etc are consistently scalar values. What I'm searching for is a good way to abstract the concept of identity, whether it be an existing library, a software pattern or just a solid good idea of some kind is provided. The proposed compound identity value would have to be comparable and usable in the business logic and passed back to the data source to specify records, entities and/or documents to affect, so the data source must be able to parse back out the details of its own compound ids. Data Source Examples: This serves to provide an idea of what I mean by various data sources having different identity implementations. A relational data source might express a piece of content with an integer identifier plus a language specific code. For example. content_id language Other Columns expressing details of content 1 en_us 1 fr_ca The identity of the first record in the above example is: 1 + en_us However when a NoSQL data source is substituted, it might somehow represent each piece of content with a GUID string 936DA01F-9ABD-4d9d-80C7-02AF85C822A8 plus language code of a different standardization, And a third kind of data source might use just a simple scalar value. So on and so forth, you get the idea.

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