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• Modify SQL result set before returning from stored procedure

  - by m0sa

  I have a simple table in my SQL Server 2008 DB: Tasks_Table -id -task_complete -task_active -column_1 -.. -column_N The table stores instructions for uncompleted tasks that have to be executed by a service. I want to be able to scale my system in future. Until now only 1 service on 1 computer read from the table. I have a stored procedure, that selects all uncompleted and inactive tasks. As the service begins to process tasks it updates the task_active flag in all the returned rows. To enable scaleing of the system I want to enable deployment of the service on more machines. Because I want to prevent a task being returned to more than 1 service I have to update the stored procedure that returns uncompleted and inactive tasks. I figured that i have to lock the table (only 1 reader at a time - I know I have to use an apropriate ISOLATION LEVEL), and updates the task_active flag in each row of the result set before returning the result set. So my question is how to modify the SELECT result set iin the stored procedure before returning it?

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• Implementing client callback functionality in WCF

  - by PoweredByOrange

  The project I'm working on is a client-server application with all services written in WCF and the client in WPF. There are cases where the server needs to push information to the client. I initially though about using WCF Duplex Services, but after doing some research online, I figured a lot of people are avoiding it for many reasons. The next thing I thought about was having the client create a host connection, so that the server could use that to make a service call to the client. The problem however, is that the application is deployed over the internet, so that approach requires configuring the firewall to allow incoming traffic and since most of the users are regular users, that might also require configuring the router to allow port forwarding, which again is a hassle for the user. My third option is that in the client, spawns a background thread which makes a call to the GetNotifications() method on server. This method on the server side then, blocks until an actual notification is created, then the thread is notified (using an AutoResetEvent object maybe?) and the information gets sent to the client. The idea is something like this: Client private void InitializeListener() { Task.Factory.StartNew(() => { while (true) { var notification = server.GetNotifications(); // Display the notification. } }, CancellationToken.None, TaskCreationOptions.LongRunning, TaskScheduler.Default); } Server public NotificationObject GetNotifications() { while (true) { notificationEvent.WaitOne(); return someNotificationObject; } } private void NotificationCreated() { // Inform the client of this event. notificationEvent.Set(); } In this case, NotificationCreated() is a callback method called when the server needs to send information to the client. What do you think about this approach? Is this scalable at all?

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• Finding What You Need in R: function arguments/parameters from outside the function's package

  - by doug

  Often in R, there are a dozen functions scattered across as many packages--all of which have the same purpose but of course differ in accuracy, performance, theoretical rigor, and so on. How do you gather all of these in one place before you start your task? So for instance: the generic plot function. Setting secondary ticks is much easier (IMHO) using a function outside of the base package, minor.tick(nx=n, ny=n, tick.ratio=n), found in Hmisc. Of course, that doesn't show up in plot's docstring. Likewise, the data-input arguments to 'plot' can be supplied by an object returned from the function 'hexbin', again, from a library outside of the base installation (where 'plot' resides). What would be great obviously is a programmatic way to gather these function arguments from the various libraries and put them in a single namespace. edit: (trying to re-state my example just above more clearly:) the arguments to plot supplied in the base package for, e.g., setting the axis tick frequency are xaxp/yaxp; however, one can also set a/t/f via a function outside of the base package, again, as in the minor.tick function from the Hmisc package--but you wouldn't know that just from looking at the plot method signature. Is there a meta function in R for this? So far, as i come across them, i've been manually gathering them in a TextMate 'snippet' (along with the attendant library imports). This isn't that difficult or time consuming, but i can only update my snippet as i find out about these additional arguments/parameters. Is there a canonical R way to do this, or at least an easier way? Just in case that wasn't clear, i am not talking about the case where multiple packages provide functions directed to the same statistic or view (e.g., 'boxplot' in the base package; 'boxplot.matrix' in gplots; and 'bplots' in Rlab). What i am talking is the case in which the function name is the same across two or more packages.

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• C++ Declarative Parsing Serialization

  - by Martin York

  Looking at Java and C# they manage to do some wicked processing based on special languaged based anotation (forgive me if that is the incorrect name). In C++ we have two problems with this: 1) There is no way to annotate a class with type information that is accessable at runtime. 2) Parsing the source to generate stuff is way to complex. But I was thinking that this could be done with some template meta-programming to achieve the same basic affect as anotations (still just thinking about it). Like char_traits that are specialised for the different types an xml_traits template could be used in a declaritive way. This traits class could be used to define how a class is serialised/deserialized by specializing the traits for the class you are trying to serialize. Example Thoughs: template<typename T> struct XML_traits { typedef XML_Empty Children; }; template<> struct XML_traits<Car> { typedef boost::mpl::vector<Body,Wheels,Engine> Children; }; template<typename T> std::ostream& Serialize(T const&) { // my template foo is not that strong. // but somthing like this. boost::mpl::for_each<typename XML_Traits<T>::Children,Serialize>(data); } template<> std::ostream& Serialize<XML_Empty>(T const&) { /* Do Nothing */ } My question is: Has anybody seen any projects/decumentation (not just XML) out there that uses techniques like this (template meta-programming) to emulate the concept of annotation used in languges like Java and C# that can then be used in code generation (to effectively automate the task by using a declaritive style). At this point in my research I am looking for more reading material and examples.

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• Visual Basic Express 2008 Help

  - by khalidfazeli

  I have been given a task to: Develop a program where a child will be presented with picture of a fruit (one of five possible fruit) on the screen at the click of a start button. The child will then try to recognise the fruit and write its name in a specified place on the screen. On the click of a check button the name of the fruit written by the child will be checked by your program and if correct will reward the child with a suitable message. If the name presented by the child is not correct, a suitable message should be presented on a red background with the correct name of the fruit included in the message. so far I have managed to create a form with 5 different fruit pictures and a text box below them. a button at the bottom of the form then checks the results and presents a message box to tell them if they have passed or failed. Private Sub btnResults_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnResults.Click If txtApple.Text = "APPLE" And txtOrange.Text = "ORANGES" And txtStrawberry.Text = "STRAWBERRIES" And txtGrapes.Text = "GRAPES" And txtBanana.Text = "BANANAS" Then MsgBox("Congratulations! you got it all right!", MsgBoxStyle.OkOnly) End Else MsgBox("Incorrect, please try again", MsgBoxStyle.OkOnly) End End If End Sub but I can't get it to randomise the picture of the fruit, so it only displays one fruit at a time and checks against it. Any help is appreciated. Thanks

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• Is there a more efficient way to do this?

  - by garethdn

  I'm hoping there is a better way to the following. I'm creating a jigsaw-type application and this is the current code i'm using: -(void) touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event { UITouch *touch = [touches anyObject]; //location of current touch CGPoint location = [touch locationInView:self.view]; if ([touch view] == img1) { [self animateFirstTouch:img1 withLocation:location]; } else if ([touch view] == img2) { [self animateFirstTouch:img2 withLocation:location]; } else if ([touch view] == img3) { [self animateFirstTouch:img3 withLocation:location]; } else if ([touch view] == img4) { [self animateFirstTouch:img4 withLocation:location]; } else if { ...... ...... } else if ([touch view] == img40) { [self animateFirstTouch:img40 withLocation:location]; return; } } I'm hoping that there is a better, more efficieny way to do this, rather than naming every image. I'm thinking something like, if touch view is equal to a UIImageView, then perform some task. The same for touchesEnded: -(void) touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event { UITouch *touch = [touches anyObject]; //location of current touch CGPoint location = [touch locationInView:self.view]; if ([touch view] == image1) { [self animateReleaseTouch:image1 withLocation:location]; } else if ([touch view] == image2) { [self animateReleaseTouch:image2 withLocation:location]; } else if ([touch view] == image3) { [self animateReleaseTouch:image3 withLocation:location]; } else if ([touch view] == image4) { [self animateReleaseTouch:image4 withLocation:location]; } else if{ ...... ...... } else if ([touch view] == image40) { [self animateReleaseTouch:image40 withLocation:location]; } return; } Any help please?

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• Capistrano + Git + DreamHost

  - by Michael Sync

  Hello, I'm trying to deploy my rails application by using Passenger and Capistrano on Dreamhost. I'm using Git as a version control and we bought an account from GitHub. I have installed all required gems, Passenger and Capistrano in my local machine and I have cloned the repository of my project from GitHub in my local machine as wel. According to Dreamhost support, they have Passenger, Ruby, Rails and etc on their server as well. I'm currently following this article http://github.com/guides/deploying-with-capistrano for my deployment. The following is my deploy.rb. default_run_options[:pty] = true ssh_options[:forward_agent] = true # be sure to change these set :user, 'gituser' set :domain, 'github.com' set :application, 'MyProjectOnGit' #[email protected]:MyProjectOnGit.git # the rest should be good set :repository, "[email protected]:MyProjectOnGit.git" set :deploy_to, "/ruby.michaelsync.net/" set :deploy_via, :remote_cache set :scm, 'git' set :branch, 'master' set :git_shallow_clone, 1 set :scm_verbose, true set :use_sudo, false set :git_enable_submodules, 1 server domain, :app, :web role :db, domain, :primary => true set :ssh_options, { :forward_agent => true } namespace :deploy do task :restart do run "touch #{current_path}/tmp/restart.txt" end end When I run "cap deploy", I'm getting the error below. [deploy:update_code] exception while rolling back: Capistrano::ConnectionError, connection failed for: github.com (Net::SSH::AuthenticationFailed: gituser) connection failed for: github.com (Net::SSH::AuthenticationFailed: gituser) Thanks in advance..

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• python os.mkfifo() for Windows

  - by user302099

  Hello. Short version (if you can answer the short version it does the job for me, the rest is mainly for the benefit of other people with a similar task): In python in Windows, I want to create 2 file objects, attached to the same file (it doesn't have to be an actual file on the hard-drive), one for reading and one for writing, such that if the reading end tries to read it will never get EOF (it will just block until something is written). I think in linux os.mkfifo() would do the job, but in Windows it doesn't exist. What can be done? (I must use file-objects). Some extra details: I have a python module (not written by me) that plays a certain game through stdin and stdout (using raw_input() and print). I also have a Windows executable playing the same game, through stdin and stdout as well. I want to make them play one against the other, and log all their communication. Here's the code I can write (the get_fifo() function is not implemented, because that's what I don't know to do it Windows): class Pusher(Thread): def __init__(self, source, dest, p1, name): Thread.__init__(self) self.source = source self.dest = dest self.name = name self.p1 = p1 def run(self): while (self.p1.poll()==None) and\ (not self.source.closed) and (not self.source.closed): line = self.source.readline() logging.info('%s: %s' % (self.name, line[:-1])) self.dest.write(line) self.dest.flush() exe_to_pythonmodule_reader, exe_to_pythonmodule_writer =\ get_fifo() pythonmodule_to_exe_reader, pythonmodule_to_exe_writer =\ get_fifo() p1 = subprocess.Popen(exe, shell=False, stdin=subprocess.PIPE, stdout=subprocess.PIPE) old_stdin = sys.stdin old_stdout = sys.stdout sys.stdin = exe_to_pythonmodule_reader sys.stdout = pythonmodule_to_exe_writer push1 = Pusher(p1.stdout, exe_to_pythonmodule_writer, p1, '1') push2 = Pusher(pythonmodule_to_exe_reader, p1.stdin, p1, '2') push1.start() push2.start() ret = pythonmodule.play() sys.stdin = old_stdin sys.stdout = old_stdout

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• How to copy files without slowing down my app?

  - by Kevin Gebhardt

  I have a bunch of little files in my assets which need to be copied to the SD-card on the first start of my App. The copy code i got from here placed in an IntentService works like a charm. However, when I start to copy many litte files, the whole app gets increddible slow (I'm not really sure why by the way), which is a really bad experience for the user on first start. As I realised other apps running normal in that time, I tried to start a child process for the service, which didn't work, as I can't acess my assets from another process as far as I understood. Has anybody out there an idea how a) to copy the files without blocking my app b) to get through to my assets from a private process (process=":myOtherProcess" in Manifest) or c) solve the problem in a complete different way Edit: To make this clearer: The copying allready takes place in a seperate thread (started automaticaly by IntentService). The problem is not to separate the task of copying but that the copying in a dedicated thread somehow affects the rest of the app (e.g. blocking to many app-specific resources?) but not other apps (so it's not blocking the whole CPU or someting) Edit2: Problem solved, it turns out, there wasn't really a problem. See my answer below.

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• PHP unlink OR rewrite own/current file by itself

  - by Email

  Hi Task: Cut or erase a file after first walk-through. i have an install file called "index.php" which creates another php file. <? /* here some code*/ $fh = fopen($myFile, 'w') or die("can't open file"); $stringData = "<?php \n echo 'hallo, *very very long text*'; \n ?>"; fwrite($fh, $stringData); /*herecut"/ /*here some code */ after the creation of the new file this file is called and i intent to erase the filecreation call since it is very long and only needed on first install. i therefor add to the above code echo 'hallo, *very very long text*'; \n ***$new= file_get_contents('index.php'); \n $findme = 'habanot'; $pos = strpos($new, $findme); if ($pos === false) { $marker='herecut';\n $new=strstr($new,$marker);\n $new='<?php \n /*habanot*/\n'.$new;\n $fh = fopen('index.php', 'w') or die 'cant open file'); $stringData = $new; fwrite($fh, $stringData); fclose($fh);*** ?>"; fwrite($fh, $stringData);]} Isnt there an easier way or a function to modify the current file or even "self destroy" a file after first call? Regards

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• Thread management advice - Is TPL a good idea?

  - by Ian

  I'm hoping to get some advice on the use of thread managment and hopefully the task parallel library, because I'm not sure I've been going down the correct route. Probably best is that I give an outline of what I'm trying to do. Given a Problem I need to generate a Solution using a heuristic based algorithm. I start of by calculating a base solution, this operation I don't think can be parallelised so we don't need to worry about. Once the inital solution has been generated, I want to trigger n threads, which attempt to find a better solution. These threads need to do a couple of things: They need to be initalized with a different 'optimization metric'. In other words they are attempting to optimize different things, with a precedence level set within code. This means they all run slightly different calculation engines. I'm not sure if I can do this with the TPL.. If one of the threads finds a better solution that the currently best known solution (which needs to be shared across all threads) then it needs to update the best solution, and force a number of other threads to restart (again this depends on precedence levels of the optimization metrics). I may also wish to combine certain calculations across threads (e.g. keep a union of probabilities for a certain approach to the problem). This is probably more optional though. The whole system needs to be thread safe obviously and I want it to be running as fast as possible. I tried quite an implementation that involved managing my own threads and shutting them down etc, but it started getting quite complicated, and I'm now wondering if the TPL might be better. I'm wondering if anyone can offer any general guidance? Thanks...

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• Why is my user control not instanciated on a postback?

  - by Antoine

  Hi, I'd like to set the trigger of an UpdatePanel to a user control outside the UpdatePanel on the same page . The user control is added at design time, not at runtime. If I statically declare the trigger, I get an error "A control with ID 'xx' cannot be found for the trigger in UpdatePanel". I tried to add the trigger at runtime in Page_Init or Page_Load, but it fails with the user control being null, although it has ViewState enabled. Has someone an idea on how to solve this? Here is the code of the user control: <%@ Control Language="C#" AutoEventWireup="true" CodeFile="ComponentDropDownControl.ascx.cs" Inherits="ComponentDropDownControl" EnableViewState="true" %> <asp:DropDownList ID="ComponentDropDown" runat="server" DataSourceID="ComponentFile" DataTextField="name" DataValueField="name" OnSelectedIndexChanged="ComponentDropDown_SelectedIndexChanged" AutoPostBack="True" EnableTheming="True"> </asp:DropDownList><asp:XmlDataSource ID="ComponentFile" runat="server" DataFile="~/App_Data/Components.xml" XPath="//component"></asp:XmlDataSource> And here it is in the aspx page: <%@ Page Language="C#" MasterPageFile="~/MasterPage.master" AutoEventWireup="true" CodeFile="create.aspx.cs" Inherits="create" Title="Create task" %> <%@ Register Src="ComponentDropDownControl.ascx" TagName="ComponentDropDownControl" TagPrefix="uc1" %> ... <uc1:ComponentDropDownControl ID="CustomComponentDropDown" runat="server" EnableViewState="true" /> In the Page_Load function of the aspx page, the following lines work at first time, but fail on the first PostBack (line 2, CustomComponentDropDown is null). AsyncPostBackTrigger trigger = new AsyncPostBackTrigger(); trigger.ControlID = CustomComponentDropDown.UniqueID.ToString(); UpdatePanel1.Triggers.Add(trigger);

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• For business people to manage, keep binary images in MySQL or just the urls?

  - by Michael Mao

  Hello everyone: I am working on a task to enable image uploading and auto-scaling(from full sized to thumbnail) by jQuery & PHP. I can naturally come up with two approaches : First, store both images as binary objects directly into MySQL; Second, store only urls to the images and keep the images somewhere on server. The images are for everyone to view, so there are no security restrictions, as far as I know. Personally I don't have any preference, however, at the end of the day, it is the business people that are going to manage the images as part of the system(CRUD). So I am wondering which seems to be a bit better for them? Of course I am building a easy-to-use, visualize web interface for the staff to control the process, but I am not sure if that is enough. Lessons told me that if I don't think for the future and seek the most flexible approach, the I will probably screw myself sooner or later. PS. The following link is what I've found so far, which is pretty cool, no flash involved :) Andrew Valum's ajax image upload jQuery plugin

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• Findbugs and comparing

  - by Rob Goodwin

  I recently started using the findbugs static analysis tool in a java build I was doing. The first report came back with loads of High Priority warnings. Being the obsessive type of person, I was ready to go knock them all out. However, I must be missing something. I get most of the warnings when comparing things. Such as the following code: public void setSpacesPerLevel(int value) { if( value >= 0) { ... produces a high priority warning at the if statement that reads. File: Indenter.java, Line: 60, Type: BIT_AND_ZZ, Priority: High, Category: CORRECTNESS Check to see if ((...) & 0) == 0 in sample.Indenter.setSpacesPerLevel(int) I am comparing an int to an int, seems like a common thing. I get quite a few of that type of error with similar simple comparisons. I have alot of other high priority warnings on what appears to be simple code blocks. Am I missing something here? I realize that static analysis can produce false positives, but the errors I am seeing seem too trivial of a case to be a false positive. This one has me scratching my head as well. for(int spaces = 0;spaces < spacesPerLevel;spaces++){... Which gives the following findbugs warning: File: Indenter.java, Line: 160, Type: IL_INFINITE_LOOP, Priority: High, Category: CORRECTNESS There is an apparent infinite loop in sample.Indenter.indent() This loop doesn't seem to have a way to terminate (other than by perhaps throwing an exception). Any ideas? So basically I have a handful of files and 50-60 high priority warnings similar to the ones above. I am using findbugs 1.3.9 and calling it from the findbugs ant task

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• How to maintain a persistant network-connection between two applications over a network?

  - by John

  I was recently approached by my management with an interesting problem - where I am pretty sure I am telling my bosses the correct information but I really want to make sure I am telling them the correct stuff. I am being asked to develop some software that has this function: An application at one location is constantly processing real-time data every second and only generates data if the underlying data has changed in any way. On the event that the data has changed send the results to another box over a network Maintains a persistent connection between the both machines, altering the remote box if for some reason the network connection went down From what I understand, I imagine that I need to do some reading on doing some sort of TCP/IP socket-level stuff. That way if the connection is dropped the remote location will be aware that the data it has received may be stale. However management seems to be very convinced that this can be accomplished using SOAP. I was under the impression that SOAP is more or less a way for a client to initiate a procedure from a server and get some results via the HTTP protocol. Am I wrong in assuming this? I haven't been able to find much information on how SOAP might be able to solve a problem like this. I feel like a lot of people around my office are using SOAP as a buzzword and that has generated a bit of confusion over what SOAP actually is - and is capable of. Any thoughts on how to accomplish this task would be appreciated!

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• MySQL query against pseudo-key-value pair data in WordPress custom query

  - by andrevr

  I'm writing a custom WordPress query to use some of the data which the Woothemes Diarise theme creates. Diarise is an event planner theme with calendar blah, blah... and uses custom fields to store the event start and end dates in WP custom fields in the *wp_postmeta* table, which implements a key-value store. So for each post in the "event" category, there are 2 records in *wp_postmeta*, named *event_start_date* and *event_end_date* that I'm interested in. The task is to compare a tourist's arrival and departure dates with the start and end dates of events, yielding a what's on list of events available. We thought we'd killed it with a grand flash of logic, that goes like this: Disregard any event that ends before the tourist arrives, and any that begin after the departure date. I wrote this query: SELECT wposts.* FROM wp_posts wposts LEFT JOIN wp_postmeta wpostmeta ON wposts.ID = wpostmeta.post_id LEFT JOIN wp_term_relationships ON (wposts.ID = wp_term_relationships.object_id) LEFT JOIN wp_term_taxonomy ON (wp_term_relationships.term_taxonomy_id = wp_term_taxonomy.term_taxonomy_id) WHERE wp_term_taxonomy.taxonomy = 'category' AND wp_term_taxonomy.term_id IN(3,4) AND ( wpostmeta.meta_key = 'event_start_date' AND NOT ( concat(subst(wpostmeta.meta_value,7,4),'-',subst(wpostmeta.meta_value,4,2),'-',subst(wpostmeta.meta_value,1,2) > '2010-07-31' ) ) AND ( wpostmeta.meta_key = 'event_end_date' AND NOT ( concat(subst(wpostmeta.meta_value,7,4),'-',subst(wpostmeta.meta_value,4,2),'-',subst(wpostmeta.meta_value,1,2) < '2010-05-01' ) ) ) ORDER BY wpostmeta.meta_value ASC And, of course it returns no records. The problem I believe is in the dual reference to wpostmeta.meta_key, but how to get around that?

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• Should I pass a SqlDataReader by reference or not when passing it out to multiple threads.

  - by deroby

  Hi all, being new to c# I've run into this 'conundrum' when passing around a SqlDataReader between different threads. Without going into too much detail, the idea is to have a main thread fetching data from the database (a large recordset) and then have a helper-task run through this record by record and doing some stuff based upon the contents of this. There is no feedback to the recordset, it simply wades through until no records are left. This works fine, but given the nature of the job at hand it should be possible to have this job spread over different threads (CPUs) to maximize throughput (the order of execution is of no significance). The question then becomes, when I pass this recordset in a SqlDataReader, do I have to use ref or not ? It kind of boils down to the question : if I pass the object around without specifying ref, won't it create new copies in memory and have records processed n times ? Or, don't I risk having the record-position being moved forward while not all fields have been fully read yet ? The latter seems more like a 'data racing' issue and probably is covered by the lock()ing mechanism (or not?). My initial take on the problem was that it doesn't really hurt passing the variable using ref, yet as a colleague put it : "you only need ref when you're doing something wrong" =) Additionally using ref restricts me from applying a Using() construction too which isn't very nice either. I thus create a "basic" project that tackles the same approach but without the ref notation. Tests so far show that it works flawlessly on a Core2Duo (2cpu) using any number of threads, yet I'm still a bit wary... What do you experts think about this ? Use ref or not ? You can find the test-project here as it seems I can't upload it to this question directly ?!? ps: it's just a test-project and I'm new to c#, so please be gentle on me when breaking down the code =P

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• Spawning a thread in python

  - by morpheous

  I have a series of 'tasks' that I would like to run in separate threads. The tasks are to be performed by separate modules. Each containing the business logic for processing their tasks. Given a tuple of tasks, I would like to be able to spawn a new thread for each module as follows. from foobar import alice, bob charles data = getWorkData() # these are enums (which I just found Python doesn't support natively) :( tasks = (alice, bob, charles) for task in tasks # Ok, just found out Python doesn't have a switch - @#$%! # yet another thing I'll need help with then ... switch case alice: #spawn thread here - how ? alice.spawnWorker(data) No prizes for guessing I am still thinking in C++. How can I write this in a Pythonic way using Pythonic 'enums' and 'switch'es, and be able to run a module in a new thread. Obviously, the modules will all have a class that is derived from a ABC (abstract base class) called Plugin. The spawnWorker() method will be declared on the Plugin interface and defined in the classes implemented in the various modules. Maybe, there is a better (i.e. Pythonic) way of doing all this?. I'd be interested in knowing

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• What's the most efficient way to load data from a file to a collection on-demand?

  - by Dan

  I'm working on a java project that will allows users to parse multiple files with potentially thousands of lines. The information parsed will be stored in different objects, which then will be added to a collection. Since the GUI won't require to load ALL these objects at once and keep them in memory, I'm looking for an efficient way to load/unload data from files, so that data is only loaded into the collection when a user requests it. I'm just evaluation options right now. I've also thought of the case where, after loading a subset of the data into the collection, and presenting it on the GUI, the best way to reload the previously observed data. Re-run the parser/Populate collection/Populate GUI? or probably find a way to keep the collection into memory, or serialize/deserialize the collection itself? I know that loading/unloading subsets of data can get tricky if some sort of data filtering is performed. Let's say that I filter on ID, so my new subset will contain data from two previous analyzed subsets. This would be no problem is I keep a master copy of the whole data in memory. I've read that google-collections are good and efficient when handling big amounts of data, and offer methods that simplify lots of things so this might offer an alternative to allow me to keep the collection in memory. This is just general talking. The question on what collection to use is a separate and complex thing. Do you know what's the general recommendation on this type of task? I'd like to hear what you've done with similar scenarios. I can provide more specifics if needed.

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• How can I call `update_attribute` for a list item in rails then actually update the html using jquery?

  - by Patrick Connor

  I want my users to be able to mark one or more items from an index view as "Active" or "Inactive" using a link. The text for the link should be state aware - so it might default to "Mark as Active" if the corresponding attribute was false or null, and "Mark as Inactive" if true. Once the user clicks the link and the attribute is updated in the controller, the link-text should update based on the new state. I am WAY off here, but this is a small sample of the code I have been trying... CONTROLLER ... respond_to :html, :js ... def update @item = Item.find(params[:id]) if @item.update_attributes(params[:item]) #Not sure of how to respond to .js here end end ... update.js.erb #how do I identify which element to update? $('#item[13456]').html("State aware text for link_to") VIEW - for item in @items = item.name = link_to "Mark as Active", item_path(item), :method => :put, :remote => true. :id => "item[#{item.id}]" I am happy to read any APIs, blogs, tutorials, etc. I just can't seem to get my hands/mind around this task. Any help or guidance is greatly appreciated!

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• How to Bind a Command in WPF

  - by MegaMind

  Sometimes we used complex ways so many times, we forgot the simplest ways to do the task. I know how to do command binding, but i always use same approach. Create a class that implements ICommand interface and from the view model i create new instance of that class and binding works like a charm. This is the code that i used for command binding public partial class MainWindow : Window { public MainWindow() { InitializeComponent(); DataContext = this; testCommand = new MeCommand(processor); } ICommand testCommand; public ICommand test { get { return testCommand; } } public void processor() { MessageBox.Show("hello world"); } } public class MeCommand : ICommand { public delegate void ExecuteMethod(); private ExecuteMethod meth; public MeCommand(ExecuteMethod exec) { meth = exec; } public bool CanExecute(object parameter) { return false; } public event EventHandler CanExecuteChanged; public void Execute(object parameter) { meth(); } } But i want to know the basic way to do this, no third party dll no new class creation. Do this simple command binding using a single class. Actual class implements from ICommand interface and do the work.

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• Is ther a Designer for MFC in Visual Studio like for windows forms in .NET?

  - by claws

  Hello, I'm a .NET programmer. I've never developed anything in MFC. Currently I had to write a C++ application (console) for some image processing task. I finished writing it. But the point is I need to design GUI also for this. Well, there won't be anything complex. Just a window with few Buttons, RadioButtons, Check Boxes, PicturesBox & few sliders. thats it. I'm using VS 2008 and was expecting a .NET style form designer. Just to test, I created a MFC project (with all default configuration) and these files were created by default: ChildFrm.cpp MainFrm.cpp mfc.cpp mfcDoc.cpp mfcView.cpp stdafx.cpp Now, I'm unable to find a Designer. There is no View Designer. I've opened all the above *.cpp and in the code editor right clicked to see "Designer View". ToolBox is just empty because I'm in code editor mode. When I built the project. This is the window I get. How to open a designer?

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• How to deploy to multiple redundant production servers with "cap deploy"?

  - by Chad Johnson

  Capistrano is working great to deploy to a single server. However, I have multiple production API servers for my web application. When I deploy, my code needs to get deployed to every API server at once. Specifying each server manually is NOT the solution I am looking for (e.g. I don't want to do "cap api1 deploy; cap api2 deploy"). Is there a way, using Capistrano, to deploy to all servers at once, with just a simple "cap deploy"? I'm wondering what changes I would need to make to a typical deploy.rb file, whether I'd need to create a separate file for each server, and whether and how the Capfile would need to be changed. Also, I need to be able to specify a different deploy_to path for each server. And ideally, I wouldn't have to repeat things in different config files for different servers (eg. wouldn't have to specify :repository, :application, etc. multiple times). I have spent hours searching Google on this and looking through tutorials, but I have found nothing helpful. Here is a snippet from my current deploy.rb file: set :application, "testapplication" set :repository, "ssh://domain.com//srv/hg/#{application}" set :scm, :mercurial set :deploy_to, "/srv/www/#{application}" role :web, "domain.com" role :app, "domain.com" role :db, "domain.com", :primary => true, :norelease => true Should I just use the multistage extension and do this? task :deploy_everything do system "cap api1 deploy" system "cap api2 deploy" system "cap api2 deploy" end That could work, but I feel like this isn't what this extension is meant for...

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• How can I timeout Client-scoped variables in Coldfusion?

  - by Joshua Carmody

  I apologize if this is a "duh" question. It seems like the answer should be easily googleable, but I haven't found it yet. I am working on a large Coldfusion application that stores a large amount of session/user data in the Client scope (ie <cfset Client.UserName = "JoshuaC"> ). I did not write this application, and I don't have the luxury of significantly refactoring it. I've been given the task of setting the Client variables to time out after 72 hours. I'm not entirely sure how to do this. If I had written the application, I would have stored the variables in the Session scope, and then changed the sessiontimeout attribute of the CFAPPLICATION tag. As it is though, I'm not sure if that timeout affects the Client variables, or what their level of persistence is. The way the application works now, the Client variables never time out, and only clearing the user's cookies, or visiting a logout page which sets all the Client-scoped application variables to "", will clear the values. Of course, I could create some kind of timestamp variable like Client.LastAccessDateTime, and put something in the Application.cfm to clear the client variables if that datetime is more than 72 hours prior to Now(). But there's got to be a better way, right?

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• Upcasting without any added data fields.

  - by Benjamin Manns

  In my project I have a generic Packet class. I would like to be able to upcast to other classes (like LoginPacket or MovePacket). The base class contains a command and arguments (greatly simplified): public class Packet { public String Command; public String[] Arguments; } I would like to have be able to convert from Packet to LoginPacket (or any other) based on a check if Packet.Command == "LOGIN". The login packet would not contain any new data members, but only methods for accessing specific arguments. For example: public class LoginPacket : Packet { public String Username { get { return Arguments[0]; } set { Arguments[0] == value; } } public String Password { get { return Arguments[1]; } set { Arguments[1] == value; } } } It would be great if I could run a simple code that would cast from Packet to LoginPacket with something like LoginPacket _Login = (LoginPacket)_Packet;, but that throws a System.InvalidCastException. It seems like this would be an easy task, as no new data is included, but I can't figure out any other way than copying everything from the Packet class to a new LoginPacket class.

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