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  • Rationale of C# iterators design (comparing to C++)

    - by macias
    I found similar topic: http://stackoverflow.com/questions/56347/iterators-in-c-stl-vs-java-is-there-a-conceptual-difference Which basically deals with Java iterator (which is similar to C#) being unable to going backward. So here I would like to focus on limits -- in C++ iterator does not know its limit, you have by yourself compare the given iterator with the limit. In C# iterator knows more -- you can tell without comparing to any external reference, if the iterator is valid or not. I prefer C++ way, because once having iterator you can set any iterator as a limit. In other words if you would like to get only few elements instead of entire collection, you don't have to alter the iterator (in C++). For me it is more "pure" (clear). But of course MS knew this and C++ while designing C#. So what are the advantages of C# way? Which approach is more powerful (which leads to more elegant functions based on iterators). What do I miss? If you have thoughts on C# vs. C++ iterators design other than their limits (boundaries), please also answer. Note: (just in case) please, keep the discussion strictly technical. No C++/C# flamewar.

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  • How can I debug PEAR auth?

    - by croceldon
    I have a directory on my site that I've implemented PEAR's Auth to run my authentication. It is working great. However, I've tried to make a copy of my site (it's going to be translated to a different language), and on this new site, the Auth process doesn't seem to be working correctly. I can login properly, but every time I try to go to a different page in the same directory, and use Auth to authorize, it forces me to login again. Here's my logic: $auth_options = array( 'dsn' => mysql://user:password@server/db', 'table' => 'users', 'usernamecol' => 'username', 'passwordcol' => 'password', 'db_fields' => '*' ); $auth = new Auth("DB", $auth_options, "login_function"); $auth->setFailedLoginCallback('bad_login'); $auth->start(); if (!$auth->checkAuth()) { die('cannot succeed in checkAuth') exit; } else { include("nocache.php"); } This is part of a file that's included in every php page I that I desire to require authentication. I can login properly once, but whenever I then try to go to a different page that requires authentication, it makes me login again (and I see the 'cannot succeed' die message at the bottom of the page). Again, this solution works fine on my original site, I copied all the files, and only changed the db server/password - it still doesn't work. And I'm using the same webhost for both. What am I doing wrong here? Or how can I debug this further?

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  • Geohashing - recursively find neighbors of neighbors

    - by itsme
    I am now looking for an elegant algorithm to recursively find neighbors of neighbors with the geohashing algorithm (http://www.geohash.org). Basically take a central geohash, and then get the first 'ring' of same-size hashes around it (8 elements), then, in the next step, get the next ring around the first etc. etc. Have you heard of an elegant way to do so? Brute force could be to take each neighbor and get their neighbors simply ignoring the massive overlap. Neighbors around one central geohash has been solved many times (here e.g. in Ruby: http://github.com/masuidrive/pr_geohash/blob/master/lib/pr_geohash.rb) Edit for clarification: Current solution, with passing in a center key and a direction, like this (with corresponding lookup-tables): def adjacent(geohash, dir) base, lastChr = geohash[0..-2], geohash[-1,1] type = (geohash.length % 2)==1 ? :odd : :even if BORDERS[dir][type].include?(lastChr) base = adjacent(base, dir) end base + BASE32[NEIGHBORS[dir][type].index(lastChr),1] end (extract from Yuichiro MASUI's lib) I say this approach will get ugly soon, because directions gets ugly once we are in ring two or three. The algorithm would ideally simply take two parameters, the center area and the distance from 0 being the center geohash only (["u0m"] and 1 being the first ring made of 8 geohashes of the same size around it (= [["u0t", "u0w"], ["u0q", "u0n"], ["u0j", "u0h"], ["u0k", "u0s"]]). two being the second ring with 16 areas around the first ring etc. Do you see any way to deduce the 'rings' from the bits in an elegant way?

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  • How to reorder table rows (drag-and-drop) along with their sub rows

    - by Eirik Johansen
    I have a table which looks like this (simplified for the example): <table> <tr class="lvl_1"> <td> Level 1 </td> </tr> <tr class="lvl_2"> <td> Level 2 </td> </tr> <tr class="lvl_3"> <td> Level 3 </td> </tr> <tr class="lvl_1"> <td> Level 1 </td> </tr> <tr class="lvl_2"> <td> Level 2 </td> </tr> <tr class="lvl_3"> <td> Level 3 </td> </tr> The content in the rows with the lvl_3 class are children of the previous lvl_2 row, and the lvl_2 rows are children of the previous lvl_1. Had the data been a list, it would have looked something like this: Level 1 -- Level 2 ---- Level 3 Level 1 -- Level 2 ---- Level 3 I'm not looking to implement drag-and-drop sorting functionality, make it possible to rearrange the level 1 and two rows. The tricky part is that once I start moving a row, the corresponding children (and grand-children, if any) should move along with it. Is this even possible with the current markup, or do I have to rearrange the code? Thanks in advance !

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  • Pass arguments to a parameter class object

    - by David R
    This is undoubtedly a simple question. I used to do this before, but it's been around 10 years since I worked in C++ so I can't remember properly and I can't get a simple constructor call working. The idea is that instead of parsing the args in main, main would create an object specifically designed to parse the arguments and return them as required. So: Parameters params = new Parameters(argc, argv) then I can call things like params.getfile() Only problem is I'm getting a complier error in Visual Studio 2008 and I'm sure this is simple, but I think my mind is just too rusty. What I've got so far is really basic: In the main: #include "stdafx.h" #include "Parameters.h" int _tmain(int argc, _TCHAR* argv[]) { Parameters params = new Parameters(argc, argv); return 0; } Then in the Parameters header: #pragma once class Parameters { public: Parameters(int, _TCHAR*[]); ~Parameters(void); }; Finally in the Parameters class: include "Stdafx.h" #include "Parameters.h" Parameters::Parameters(int argc, _TCHAR* argv[]) { } Parameters::~Parameters(void) { } I would appreciate if anyone could see where my ageing mind has missed the really obvious. Thanks in advance.

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  • Application Code Redesign to reduce no. of Database Hits from Performance Perspective

    - by Rachel
    Scenario I want to parse a large CSV file and inserts data into the database, csv file has approximately 100K rows of data. Currently I am using fgetcsv to parse through the file row by row and insert data into Database and so right now I am hitting database for each line of data present in csv file so currently database hit count is 100K which is not good from performance point of view. Current Code: public function initiateInserts() { //Open Large CSV File(min 100K rows) for parsing. $this->fin = fopen($file,'r') or die('Cannot open file'); //Parsing Large CSV file to get data and initiate insertion into schema. while (($data=fgetcsv($this->fin,5000,";"))!==FALSE) { $query = "INSERT INTO dt_table (id, code, connectid, connectcode) VALUES (:id, :code, :connectid, :connectcode)"; $stmt = $this->prepare($query); // Then, for each line : bind the parameters $stmt->bindValue(':id', $data[0], PDO::PARAM_INT); $stmt->bindValue(':code', $data[1], PDO::PARAM_INT); $stmt->bindValue(':connectid', $data[2], PDO::PARAM_INT); $stmt->bindValue(':connectcode', $data[3], PDO::PARAM_INT); // Execute the statement $stmt->execute(); $this->checkForErrors($stmt); } } I am looking for a way wherein instead of hitting Database for every row of data, I can prepare the query and than hit it once and populate Database with the inserts. Any Suggestions !!! Note: This is the exact sample code that I am using but CSV file has more no. of field and not only id, code, connectid and connectcode but I wanted to make sure that I am able to explain the logic and so have used this sample code here. Thanks !!!

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  • Linear Search with Jagged Array?

    - by Nerathas
    Hello, I have the following program that creates 100 random elements trough a array. Those 100 random value's are unique, and every value only gets displayed once. Although with the linear search it keeps looking up the entire array. How would i be able to get a Jagged Array into this, so it only "scans" the remaining places left? (assuming i keep the table at 100 max elements, so if one random value is generated the array holds 99 elements with linear search scans and on...) I assume i would have to implent the jagged array somewhere in the FoundLinearInArray? Hopefully this made any sence. Regards. private int ValidNumber(int[] T, int X, int Range) { Random RndInt = new Random(); do { X = RndInt.Next(1, Range + 1); } while (FoundLinearInArray(T, X)); return X; }/*ValidNumber*/ private bool FoundLinearInArray(int[] A, int X) { byte I = 0; while ((I < A.Length) && (A[I] != X)) { I++; } return (I < A.Length); }/*FoundInArray*/ public void FillArray(int[] T, int Range) { for (byte I = 0; I < T.Length; I++) { T[I] = ValidNumber(T, I, Range); } }/*FillArray*/

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  • I need to recover an instance of an activity

    - by Bilthon
    Well.. the title is pretty descriptive, I have a bunch of tab activities (which I implemented myself, didn't want to use the tabviews with activities inside them), so It's basically 5 activities calling each other every time the user clicks on the tabs displayed as a row of LinearLayouts at the bottom of the screen. The thing is that the way I do it now, everytime the user jumps from one activity to another, a new activity is created and launched. Of course, I can see I'm wasting resources this way. So what I would like to do is to create every activity only once; and then if the user wants to go back to the previous (or any one that was already created and is probably paused) just check on some kind of list or array to see if the activity can be recovered and only in the case it can't; to lauch a new one. My question is, how can I check this? should I save the intents? and how to recover the activities afterwards? I'm kind of new with java. Greetings Nelson R. Perez

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  • MAC : How to check if the file is still being copied in cpp?

    - by Peda Pola
    In my current project, we had a requirement to check if the file is still copying. We have already developed a library which will give us OS notification like file_added , file_removed , file_modified, file_renamed on a particular folder along with the corresponding file path. The problem here is that, lets say if you add 1 GB file, it is giving multiple notification such as file_added , file_modified, file_modified as the file is being copied. Now i decided to surpass these notifications by checking if the file is copying or not. Based on that i will ignore events. I have written below code which tells if the file is being copied or not which takes file path as input parameter. Details:- In Mac, while file is being copied the creation date is set as some date less than 1970. Once it is copied the date is set to current date. Am using this technique. Based on this am deciding that file is being copied. Problem:- when we copy file in the terminal it is failing. Please advice me any approach. bool isBeingCopied(const boost::filesystem::path &filePath) { NSAutoreleasePool *pool = [[NSAutoreleasePool alloc] init]; bool isBeingCopied = false; if([[[[NSFileManager defaultManager] attributesOfItemAtPath:[NSString stringWithUTF8String:filePath.string().c_str()] error:nil] fileCreationDate] timeIntervalSince1970] < 0) { isBeingCopied = true; } [pool release]; return isBeingCopied; }

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  • Cocoa NSTextField Drag & Drop Requires Subclass... Really?

    - by ipmcc
    Until today, I've never had occasion to use anything other than an NSWindow itself as an NSDraggingDestination. When using a window as a one-size-fits-all drag destination, the NSWindow will pass those messages on to its delegate, allowing you to handle drops without subclassing NSWindow. The docs say: Although NSDraggingDestination is declared as an informal protocol, the NSWindow and NSView subclasses you create to adopt the protocol need only implement those methods that are pertinent. (The NSWindow and NSView classes provide private implementations for all of the methods.) Either a window object or its delegate may implement these methods; however, the delegate’s implementation takes precedence if there are implementations in both places. Today, I had a window with two NSTextFields on it, and I wanted them to have different drop behaviors, and I did not want to allow drops anywhere else in the window. The way I interpret the docs, it seems that I either have to subclass NSTextField, or make some giant spaghetti-conditional drop handlers on the window's delegate that hit-checks the draggingLocation against each view in order to select the different drop-area behaviors for each field. The centralized NSWindow-delegate-based drop handler approach seems like it would be onerous in any case where you had more than a small handful of drop destination views. Likewise, the subclassing approach seems onerous regardless of the case, because now the drop handling code lives in a view class, so once you accept the drop you've got to come up with some way to marshal the dropped data back to the model. The bindings docs warn you off of trying to drive bindings by setting the UI value programmatically. So now you're stuck working your way back around that too. So my question is: "Really!? Are those the only readily available options? Or am I missing something straightforward here?" Thanks.

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  • Prolog Backtracking

    - by AhmadAssaf
    I am trying to do a word calculator .. read words from a file .. translate them into numbers and then calculate the result .. i managed to do all of that but i think i have two bugs in my program .. I mainly have two functions ... extract(Words), calculate( Words,0). extract will read from the file .. and then return a list of Words .. ex: [one,plus,three] .. now calculate will translate the value for these words into numbers and calculate .. i managed to do that also .. now the bugs are : i must stop reading and terminate if i encounter stop in the file .. so if Words was [stop] End. i tried the following ... execute :- extract(Words), Words = [stop],nl,print('Terminating ...'),!. execute :- extract(Words), calculate( Words,0). it successfully terminates .. but it skips lines as i extract more than once .. i have tried to do .. execute :- extract(Words), Words \= [stop],execute(Words). execute(Words) :- calculate( Words,0). if the Words is not stop .. then go and calculate .. but its not working !! i appreciate the help .. Thank You

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  • Use of properties vs backing-field inside owner class

    - by whatispunk
    I love auto-implemented properties in C# but lately there's been this elephant standing in my cubicle and I don't know what to do with him. If I use auto-implemented properties (hereafter "aip") then I no longer have a private backing field to use internally. This is fine because the aip has no side-effects. But what if later on I need to add some extra processing in the get or set? Now I need to create a backing-field so I can expand my getters and setters. This is fine for external code using the class, because they won't notice the difference. But now all of the internal references to the aip are going to invoke these side-effects when they access the property. Now all internal access to the once aip must be refactored to use the backing-field. So my question is, what do most of you do? Do you use auto-implemented properties or do you prefer to always use a backing-field? What do you think about properties with side-effects?

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  • Silverlight Image Data Binding

    - by Alexander
    I am new to Silverlight, and have an issue with binding. I have a class ItemsManager, that has inside its scope another class Item. class ItemsManager { ... class Item : INotifyPropertyChanged { ... private BitmapImage bitmapSource; public BitmapImage BitmapSource { get { return bitmapSource; } set { bitmapSource = value; if(PropertyChanged != null )PropertyChanged("BitmapSource") } } } } I do the following in code to test binding: { ItemsManager.Instance.AddItem("123"); //Items manager started downloading item visual //part (in my case bitmap image png) Binding b = new Binding("Source"); b.Source = ItemsManager.Instance.GetItem("123").BitmapSource; b.BindsDirectlyToSource = true; Image img = new Image(); img.SetBinding(Image.SourceProperty, b); img.Width = (double)100.0; img.Height = (double)100.0; LayoutRoot.Children.Add(img); } Once image is loaded, image doesn't appear. Though, if I set directly after image has been loaded its source, it displays well. I also noticed that PropertyChanged("BitmapSource") never fires, because PropertyChanged is null, like Image never binded to it. I am looking forward to hearing from you!

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  • Is it safe to delete rotated MySQL binary logs?

    - by Milan Babuškov
    I have a MySQL server with binary logging active. Once a days logs file is "rotated", i.e. MySQL seems to stop writing to it and creates and new log file. For example, I currently have these files in /var/lib/mysql -rw-rw---- 1 mysql mysql 10485760 Jun 7 09:26 ibdata1 -rw-rw---- 1 mysql mysql 5242880 Jun 7 09:26 ib_logfile0 -rw-rw---- 1 mysql mysql 5242880 Jun 2 15:20 ib_logfile1 -rw-rw---- 1 mysql mysql 1916844 Jun 6 09:20 mybinlog.000004 -rw-rw---- 1 mysql mysql 61112500 Jun 7 09:26 mybinlog.000005 -rw-rw---- 1 mysql mysql 15609789 Jun 7 13:57 mybinlog.000006 -rw-rw---- 1 mysql mysql 54 Jun 7 09:26 mybinlog.index and mybinlog.000006 is growing. Can I simply take mybinlog.000004 and mybinlog.000005, zip them up and transfer to another server, or I need to do something else before? What info is stored in mybinlog.index? Only the info about the latest binary log? UPDATE: I understand I can delete the logs with PURGE BINARY LOGS which updates mybinlog.index file. However, I need to transfer logs to another computer before deleting them (I test if backup is valid on another machine). To reduce the transfer size, I wish to bzip2 the files. What will PURGE BINARY LOGS do if log files are not "there" anymore?

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  • jQuery validate problem

    - by tohop
    Hi there. I have a jquery dialog box that pops up and takes user data through a form. Once the user is finished s/he clicks the 'ok' button. This dialog box has a few 'tabs' such that when 'ok' is clicked, we want to validate all the data given in each tab. If anything is invalid, we take the user to that tab and tell them what's wrong. However, it takes 2 clicks of 'ok' to achieve this. Here is the offending jquery: if(errors){ // display the tab with the error jQuery('#recording_tabs > div').each( function(i){ alert('we are here'); if(jQuery(this).find('*').not('label').hasClass('invalid')){ jQuery('#recording_tabs').tabs('option','selected', i); return false;// prevent further processing } }); } So what happens in the above code is that when we click 'ok' we get a 'we are here' alert for each div (tab) and then nothing happens. Clicking 'ok' again gives us the 'we are here' alert up until we are taken to the tab with the errors. So obviously the first time round the inner if statement is false for each tab which probably means jQuery hasn't registered the 'invalid' classes in time. So I tried a blank each() statement just before the main one in the hope that it would fix the problem jQuery('#recording_tabs > div').each( function(i){} ); But I got the same result. Can anyone spot anything I am missing?

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  • jQuery indexOf select box manipulation

    - by kenny99
    Hi, I'm trying to figure out how to remove options from a select box when that option has been selected in an adjacent select box. Basically the user has the option to add multiple records here via select boxes, but I want to remove the list of options available to them so that, for example, they can't enter the same value in two select boxes. When an Add More button is clicked, I fade in the next select box container. A number of select boxes have been generated by PHP and I use JS to hide them. Each select box has a unique number appended to the ID, so i want to access those select boxes which contain the string "other_pet_types", then I want to iterate through the currently visible ones and build an array of the values which have been selected, which I will then remove from the list of options in the newly displayed select box. This is what I have so far, but it's definitely not right - I can't get the initial test on the ID to work. Any pointers greatly appreciated as i realise i'm pretty wide of the mark at the moment! var vals = new Array(); //build array with currently selected options $('p.mult_entries select').each(function(){ vals += $(this).val(); }); $("p.mult_entries:hidden:first").fadeIn("slow", function() { $(this).find(('select').attr('id').indexOf('other_pet_types') > 0).each(function(){ console.log($(this).val()); //as expected prints nothing - need to iterate through the options of the above select //once i extract the correct values, iterate through new select box and use inArray to remove options where that value already exists in one of previous select boxes }); });

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  • BufferedImage.getGraphics() resulting in memory leak, is there a fix?

    - by user359202
    Hi friends, I'm having problem with some framework API calling BufferedImage.getGraphics() method and thus causing memory leak. What this method does is that it always calls BufferedImage.createGraphics(). On a windows machine, createGraphics() is handled by Win32GraphicsEnvironment which keeps a listeners list inside its field displayChanger. When I call getGraphics on my BufferedImage someChart, someChart's SurfaceManager(which retains a reference to someChart) is added to the listeners map in Win32GraphicsEnvironment, preventing someChart to be garbage collected. Nothing afterwards removes someChart's SurfaceManager from the listeners map. In general, the summarized path stopping a BufferedImage from being garbage collected, once getGraphics is called, is as follows: GC Root - localGraphicsEnvironment(Win32GraphicsEnvironment) - displayChanger(SunDisplayChanger) - listeners(Map) - key(D3DChachingSurfaceManager) - bImg(BufferedImage) I could have changed the framework's code so that after every called to BufferedImage.getGraphics(), I keep a reference to the BufferedImage's SurfaceManager. Then, I get hold of localGraphicsEnvironment, cast it to Win32GraphicsEnvironment, then call removeDisplayChangedListener() using the reference to the BufferedImage's SurfaceManager. But I don't think this is a proper way to solve the problem. Could someone please help me with this issue? Thanks a lot!

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  • How can I make Access think there is a primary key

    - by user3692757
    I have a table and I'm trying to join it with another table, but it doesn't have a distinctive primary key. The two tables do share similarities, “Acct” and “Location”. If I could concatenate “Acct&Location” it would become a primary key, but Access won’t let me make a primary key from a calculation. I provided a small sample below. Each hospital has an “Acct”, but the “Acct” will show up once for each “Location”. How can I make join these in a relationship? I connected the two in a relationships and tried to “Enforce Referential Integrity”, but it indicated “No unique index found for the referenced field of the primary key”. Also, if I run a “Find UnMatched Query” it doesn’t find anything. I think its because I can’t make it realize that in combination “Acct” and “Location” can be perceived as primary keys when used in conjunction of each other. Acct 1 2 3 1 2 3 1 2 3| Location ABI ABI ABI NHO NHO NHO NTX NTX NTX I tried to load an image to illustrate it better, but I haven't made enough post.

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  • mootools event listener disappears after element.innerHTML is changed

    - by baiano
    I putting together a page that will display a set of stored values. I am using mootools and AJAX calls to update the values without needing to refresh the page each time the user selects a new item from the drop down menus. the HTML each line looks something like: <div class="selections"> <input class="checkbox selector" type="checkbox" CHECKED /> <span class="b_name"> <select class="b_n selector"> <!-- options --> </select> </span> <span class="b_level"> <select class="b_l selector"> <!-- options --> </select> </span> <span class="values"> <!-- the values --> </span> In the head I have set up an event listener like: $$('.selector').addEvent('change', function(event){changeValues(this);}); My problem is that when the "b_name" select changes I have to update the list of options in the "b_level" select. I accomplish that by getting a list of the possible options from my database through a php script on another page and replacing "b_level"'s innerHTML. Once I do that, the event listener attached to "b_l selector" no longer works. I tried to resolve this issue by explicitly attaching an event listener to "b_l selector" each time "b_name" changes like so: row.getElement('.b_l').addEvent('change', function(event){changeValues(row.getElement('.b_l'));}); where 'row' is the html element 'div.selections'. It still isn't working and I have no idea what's going on. Can anyone offer a suggestion as to how I can get this resolved? or perhaps a better way to do what I'm doing. Thanks

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  • Organizing a String based on maxlength of each field

    - by pringlesinn
    I've made a program that makes my life easier by reading a class and creating methods like these below: //Ferramentas Parâmetros acessos.add(new AcessoBean("Ferramentas", "Parâmetros", "Parâmetros", "Pesquisa", "ppaParametrosList", null, TipoAcessoBean.TELA)); acessos.add(new AcessoBean("Ferramentas", "Parâmetros", "Parâmetros", "Gravar", "ppaParametrosHome", "persist", TipoAcessoBean.ACAO)); acessos.add(new AcessoBean("Ferramentas", "Parâmetros", "Parâmetros", "Atualizar Dados", "ppaParametrosHome", "update", TipoAcessoBean.ACAO)); acessos.add(new AcessoBean("Ferramentas", "Parâmetros", "Parâmetros", "Leitura", "ppaParametrosHome", "find", TipoAcessoBean.ACAO)); acessos.add(new AcessoBean("Ferramentas", "Parâmetros", "Parâmetros", "Excluir", "ppaParametrosHome", "remove", TipoAcessoBean.ACAO)); Don't worry about the language. It won't make it harder to understand what I need to make. I want to organize it to be shown like this: //Ferramentas Parâmetros acessos.add(new AcessoBean("Ferramentas", "Parâmetros", "Parâmetros", "Pesquisa" , "ppaParametrosList", null , TipoAcessoBean.TELA)); acessos.add(new AcessoBean("Ferramentas", "Parâmetros", "Parâmetros", "Gravar" , "ppaParametrosHome", "persist", TipoAcessoBean.ACAO)); acessos.add(new AcessoBean("Ferramentas", "Parâmetros", "Parâmetros", "Atualizar Dados", "ppaParametrosHome", "update" , TipoAcessoBean.ACAO)); acessos.add(new AcessoBean("Ferramentas", "Parâmetros", "Parâmetros", "Leitura" , "ppaParametrosHome", "find" , TipoAcessoBean.ACAO)); acessos.add(new AcessoBean("Ferramentas", "Parâmetros", "Parâmetros", "Excluir" , "ppaParametrosHome", "remove" , TipoAcessoBean.ACAO)); I'm reading the whole class with Scanner, but once I read, I save only the things I want in a Collection containing this things above. How can I make a method to complete with blank to make it organized?

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  • How can I merge two Linq IEnumerable<T> queries without running them?

    - by makerofthings7
    How do I merge a List<T> of TPL-based tasks for later execution? public async IEnumerable<Task<string>> CreateTasks(){ /* stuff*/ } My assumption is .Concat() but that doesn't seem to work: void MainTestApp() // Full sample available upon request. { List<string> nothingList = new List<string>(); nothingList.Add("whatever"); cts = new CancellationTokenSource(); delayedExecution = from str in nothingList select AccessTheWebAsync("", cts.Token); delayedExecution2 = from str in nothingList select AccessTheWebAsync("1", cts.Token); delayedExecution = delayedExecution.Concat(delayedExecution2); } /// SNIP async Task AccessTheWebAsync(string nothing, CancellationToken ct) { // return a Task } I want to make sure that this won't spawn any task or evaluate anything. In fact, I suppose I'm asking "what logically executes an IQueryable to something that returns data"? Background Since I'm doing recursion and I don't want to execute this until the correct time, what is the correct way to merge the results if called multiple times? If it matters I'm thinking of running this command to launch all the tasks var AllRunningDataTasks = results.ToList(); followed by this code: while (AllRunningDataTasks.Count > 0) { // Identify the first task that completes. Task<TableResult> firstFinishedTask = await Task.WhenAny(AllRunningDataTasks); // ***Remove the selected task from the list so that you don't // process it more than once. AllRunningDataTasks.Remove(firstFinishedTask); // TODO: Await the completed task. var taskOfTableResult = await firstFinishedTask; // Todo: (doen't work) TrustState thisState = (TrustState)firstFinishedTask.AsyncState; // TODO: Update the concurrent dictionary with data // thisState.QueryStartPoint + thisState.ThingToSearchFor Interlocked.Decrement(ref thisState.RunningDirectQueries); Interlocked.Increment(ref thisState.CompletedDirectQueries); if (thisState.RunningDirectQueries == 0) { thisState.TimeCompleted = DateTime.UtcNow; } }

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  • JPA returning null for deleted items from a set

    - by Jon
    This may be related to my question from a few days ago, but I'm not even sure how to explain this part. (It's an entirely different parent-child relationship.) In my interface, I have a set of attributes (Attribute) and valid values (ValidValue) for each one in a one-to-many relationship. In the Spring MVC frontend, I have a page for an administrator to edit these values. Once it's submitted, if any of these fields (as <input> tags) are blank, I remove the ValidValue object like so: Set<ValidValue> existingValues = new HashSet<ValidValue>(attribute.getValidValues()); Set<ValidValue> finalValues = new HashSet<ValidValue>(); for(ValidValue validValue : attribute.getValidValues()) { if(!validValue.getValue().isEmpty()) { finalValues.add(validValue); } } existingValues.removeAll(finalValues); for(ValidValue removedValue : existingValues) { getApplicationDataService().removeValidValue(removedValue); } attribute.setValidValues(finalValues); getApplicationDataService().modifyAttribute(attribute); The problem is that while the database is updated appropriately, the next time I query for the Attribute objects, they're returned with an extra entry in their ValidValue set -- a null, and thus, the next time I iterate through the values to display, it shows an extra blank value in the middle. I've confirmed that this happens at the point of a merge or find, at the point of "Execute query ReadObjectQuery(entity.Attribute). Here's the code I'm using to modify the database (in the ApplicationDataService): public void modifyAttribute(Attribute attribute) { getJpaTemplate().merge(attribute); } public void removeValidValue(ValidValue removedValue) { ValidValue merged = getJpaTemplate().merge(removedValue); getJpaTemplate().remove(merged); } Here are the relevant parts of the entity classes: Entity @Table(name = "attribute") public class Attribute { @OneToMany(cascade = CascadeType.ALL, fetch = FetchType.LAZY, mappedBy = "attribute") private Set<ValidValue> validValues = new HashSet<ValidValue>(0); } @Entity @Table(name = "valid_value") public class ValidValue { @ManyToOne(fetch = FetchType.LAZY) @JoinColumn(name = "attr_id", nullable = false) private Attribute attribute; }

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  • Using static variables for Strings

    - by Vivart
    below content is taken from Best practice: Writing efficient code but i didn't understand why private static String x = "example"; faster than private static final String x ="example"; Can anybody explain this. Using static variables for Strings When you define static fields (also called class fields) of type String, you can increase application speed by using static variables (not final) instead of constants (final). The opposite is true for primitive data types, such as int. For example, you might create a String object as follows: private static final String x = "example"; For this static constant (denoted by the final keyword), each time that you use the constant, a temporary String instance is created. The compiler eliminates "x" and replaces it with the string "example" in the bytecode, so that the BlackBerry® Java® Virtual Machine performs a hash table lookup each time that you reference "x". In contrast, for a static variable (no final keyword), the String is created once. The BlackBerry JVM performs the hash table lookup only when it initializes "x", so access is faster. private static String x = "example"; You can use public constants (that is, final fields), but you must mark variables as private.

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  • EF4 + STE: Reattaching via a WCF Service? Using a new objectcontext each and every time?

    - by Martin
    Hi there, I am planning to use WCF (not ria) in conjunction with Entity Framework 4 and STE (Self tracking entitites). If i understnad this correctly my WCF should return an entity or collection of entities (using LIST for example and not IQueryable) to the client (in my case silverlight) The client then can change the entity or update it. At this point i believe it is self tracking???? This is where i sort of get a bit confused as there are a lot of reported problems with STEs not tracking.. Anyway... Then to update i just need to send back the entity to my WCF service on another method to do the update. I should be creating a new OBJECTCONTEXT everytime? In every method? If i am creaitng a new objectcontext everytime in everymethod on my WCF then don't i need to re-attach the STE to the objectcontext? So basically this alone wouldn't work?? using(var ctx = new MyContext()) { ctx.Orders.ApplyChanges(order); ctx.SaveChanges(); } Or should i be creating the object context once in the constructor of the WCF service so that 1 call and every additional call using the same wcf instance uses the same objectcontext? I could create and destroy the wcf service in each method call from the client - hence creating in effect a new objectcontext each time. I understand that it isn't a good idea to keep the objectcontext alive for very long. Any insight or information would be gratefully appreciated thanks

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  • PHP OAuth Twitter

    - by Sandhurst
    I have created a twitter app which I am using to post tweets. The problem that I am not able to resolve is everytime I have to allow access to my application. so lets say I need to tweet three messages, so all the three times I have to allow access to my app. I just need that once user has allowed access to my app, next time he should only be asked to allow acces is that when he/she relogins. Here's my code that I am using Share content on twitter"; include 'lib/EpiCurl.php'; include 'lib/EpiOAuth.php'; include 'lib/EpiTwitter.php'; include 'lib/secret.php'; $twitterObj = new EpiTwitter($consumer_key, $consumer_secret); $oauth_token = $_GET['oauth_token']; if($oauth_token == '') { $url = $twitterObj-getAuthorizationUrl(); echo ""; echo "Sign In with Twitter"; echo ""; } else { $twitterObj-setToken($_GET['oauth_token']); $token = $twitterObj-getAccessToken(); $twitterObj-setToken($token-oauth_token, $token-oauth_token_secret); $_SESSION['ot'] = $token-oauth_token; $_SESSION['ots'] = $token-oauth_token_secret; $twitterInfo= $twitterObj-get_accountVerify_credentials(); $twitterInfo-response; $username = $twitterInfo-screen_name; $profilepic = $twitterInfo-profile_image_url; include 'update.php'; } if(isset($_POST['submit'])) { $msg = $_REQUEST['tweet']; $twitterObj-setToken($_SESSION['ot'], $_SESSION['ots']); $update_status = $twitterObj-post_statusesUpdate(array('status' = $msg)); $temp = $update_status-response; header("Location: MessageStatus.html"); exit(); } ?

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