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  • JDOQL Any way to avoid multiple .contains() calls in the query when searching for the presence of on

    - by Finbarr
    The question pretty much says it all. If I have a class Class A public class A { ... private List<String> keys; ... } And I want to select all A instances from the DataStore that have atleast one of a List of keys, is there a better way of doing it than this: query = pm.newQuery(A.class); query.setFilter("keys.contains(:key1) || keys.contains(:key2) || keys.contains(:key3)"); List<A> results = (List<A>)query.execute(key1, key2, key3); This has not yet been implemented, so I am open to radical suggestions.

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  • Asp.Net (C#) MVC Routing - Trying avoid using the same controller in different places and think rout

    - by sheefy
    Hi Guys, I'm currently building a site which has a bunch of main categories and in each category you can perform a search. Basically, I want my addresses to work like this... When the website loads (as in when someone goes to www.mySite.com) it will redirect them to the default category. www.mySite.com/Category Then when you search within a category, the results would come up in a page like the following. www.mySite.com/Category/Search I want to put everything in one controller and have one main view for the Category and one for the Search, I would then render these based on which category is currently being viewed. Can this be done, maybe with routing? I don't want to have to create a different controller for each category as it's just duplicating a lot of the code. Thanks in advance for your help.

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  • How to avoid GUI freeze when calling Beginthread API?

    - by isa
    Below just a simple race between 2 button in 2 threads, and this will freeze other components on the form. procedure moveButton1(); var I: Integer; begin for I := 0 to 6000 do Form1.Button1.Left := Form1.Button1.Left - 1; Form1.Caption := 'Button1 won!'; EndThread(0); end; procedure moveButton2(); var I: Integer; begin for I := 0 to 6000 do Form1.Button2.Left := Form1.Button2.Left - 1; Form1.Caption := 'Button2 won!'; EndThread(0); end; procedure TForm1.Button3Click(Sender: TObject); var thread1, thread2,tick : Integer; id1, id2 : LongWord; begin thread1 := BeginThread(nil, 0, Addr(moveButton1), nil, 0, id1); thread2 := BeginThread(nil, 0, Addr(moveButton2), nil, 0, id2); CloseHandle(thread1); CloseHandle(thread2); end;

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  • How to avoid translation tools from messing up HTML tags?

    - by janoChen
    I always use Google translate and paste back the the results in Vim. But for some reason Google translate also screws up the HTML tags around the content I want to translate. Is there a solution for this? For instance, the double quotes are translated to Chinese-cased double quotes: 'pictures_h2'=>“?????????? Strong and li tags are translated too (well I kinda expected that). P S : IS there any translator which respect HTML tags? or translation plugin for Vim?

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  • How to avoid geometric slowdown with large Linq transactions?

    - by Shaul
    I've written some really nice, funky libraries for use in LinqToSql. (Some day when I have time to think about it I might make it open source... :) ) Anyway, I'm not sure if this is related to my libraries or not, but I've discovered that when I have a large number of changed objects in one transaction, and then call DataContext.GetChangeSet(), things start getting reaalllly slooowwwww. When I break into the code, I find that my program is spinning its wheels doing an awful lot of Equals() comparisons between the objects in the change set. I can't guarantee this is true, but I suspect that if there are n objects in the change set, then the call to GetChangeSet() is causing every object to be compared to every other object for equivalence, i.e. at best (n^2-n)/2 calls to Equals()... Yes, of course I could commit each object separately, but that kinda defeats the purpose of transactions. And in the program I'm writing, I could have a batch job containing 100,000 separate items, that all need to be committed together. Around 5 billion comparisons there. So the question is: (1) is my assessment of the situation correct? Do you get this behavior in pure, textbook LinqToSql, or is this something my libraries are doing? And (2) is there a standard/reasonable workaround so that I can create my batch without making the program geometrically slower with every extra object in the change set?

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  • How to avoid strange characters before the request in firefox?

    - by murze
    Hi, on a website i'm currently developing I'm using jquery to do all sort of magic things :-) In firefox however, when I load jquery 1.4.2 there are sometimes funny characters in front of the request. You can see the strangers characters in this screenshot (thank you firebug). In safari, Chrome and IE these funny characters don't appear, jquery is loading fine in those browsers. Why are those characters appearing and how can I remove them? Thanks!!

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  • How do I avoid killing the native controls on a html5-video when i've started it programmaticly?

    - by Nils
    OK, so the deal is I've started making a little videoplayer, that works by clicking a div with an image, expanding the div and the image, and then exchanges the image with a html5-videotag. the code is as below. (It's very early on, so i know theres a lot that need improving, as in not using javascript to set styles and so on, but nevertheless, any insigts and tips are welcome, besides the answer to the main question) /*Begin Expander*/ var $videoplayer = $('<video width="640" height="360" preload="none" controls="" tabindex="0" style="position: relative;"><source type="video/mp4" src="/restalive/movies/big_buck_bunny.mp4"></source><source type="video/ogg" src="/restalive/movies/big_buck_bunny.ogv"></source></video>').appendTo('body'); $videoplayer.hide(); $(".ExpandVideo").each(function(i){ var $trigger = $(this); var $image = $trigger.find("img"); $image.css({ "width" : "100%" ,"height" : "auto" }) $trigger.css({ "display" : "block" ,"overflow" : "hidden" ,"width" : "200px" ,"float" : "left" }); $trigger.bind("click", function(e){ $trigger.animate({"width" : "640px"}, "fast", function(){ $image.replaceWith($videoplayer); $videoplayer.show(); $videoplayer.attr("id", "video" + i); var video = document.getElementById("video" + i); video.play(); }) }) }); However, the main problem is that when i've fired of the video like this (video.play()), the native controls stop working, i can no longer pause the video, even though the controls are there, and clickable, the video just starts playing immidiatley again when i trie to pause it. Which is a shame, because i want to use the native controls for simplicity.

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  • Any way to avoid a filesort when order by is different to where clause?

    - by Julian
    I have an incredibly simple query (table type InnoDb) and EXPLAIN says that MySQL must do an extra pass to find out how to retrieve the rows in sorted order. SELECT * FROM `comments` WHERE (commentable_id = 1976) ORDER BY created_at desc LIMIT 0, 5 exact explain output: table select_type type extra possible_keys key key length ref rows comments simple ref using where; using filesort common_lookups common_lookups 5 const 89 commentable_id is indexed. Comments has nothing trick in it, just a content field. The manual suggests that if the order by is different to the where, there is no way filesort can be avoided. http://dev.mysql.com/doc/refman/5.0/en/order-by-optimization.html I also tried order by id as well as it's equivalent but makes no difference, even if I add id as an index (which I understand is not required as id is indexed implicitly in MySQL). thanks in advance for any ideas!

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  • How to avoid web server traffic peak resulting from iOS Newsstand app receiving a remote notification?

    - by thomers
    I'm developing an iOS Newsstand app. If it is suspended or not running and connected to a WLAN, Newsstand apps can be triggered by a Push remote notification to download the latest issue (in our case around 100MB) in the background. I'm using Urban Airship for the delivery of the Push broadcast. I'm now worrying about many many iOS devices hitting the web server for one big download more or less at the same time, because I expect the majority of the devices will receive the notification in a very short timeframe. Instead of broadcasts to all devices, should I rather send individual notifications to batches of small groups of devices, spreading them out over a longer period of time? And/or would a CDN like Amazon Cloudfront solve that issue easier/anyway?

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  • How do I avoid a race condition in my Rails app?

    - by Cathal
    Hi, I have a really simple Rails application that allows users to register their attendance on a set of courses. The ActiveRecord models are as follows: class Course < ActiveRecord::Base has_many :scheduled_runs ... end class ScheduledRun < ActiveRecord::Base belongs_to :course has_many :attendances has_many :attendees, :through => :attendances ... end class Attendance < ActiveRecord::Base belongs_to :user belongs_to :scheduled_run, :counter_cache => true ... end class User < ActiveRecord::Base has_many :attendances has_many :registered_courses, :through => :attendances, :source => :scheduled_run end A ScheduledRun instance has a finite number of places available, and once the limit is reached, no more attendances can be accepted. def full? attendances_count == capacity end attendances_count is a counter cache column holding the number of attendance associations created for a particular ScheduledRun record. My problem is that I don't fully know the correct way to ensure that a race condition doesn't occur when 1 or more people attempt to register for the last available place on a course at the same time. My Attendance controller looks like this: class AttendancesController < ApplicationController before_filter :load_scheduled_run before_filter :load_user, :only => :create def new @user = User.new end def create unless @user.valid? render :action => 'new' end @attendance = @user.attendances.build(:scheduled_run_id => params[:scheduled_run_id]) if @attendance.save flash[:notice] = "Successfully created attendance." redirect_to root_url else render :action => 'new' end end protected def load_scheduled_run @run = ScheduledRun.find(params[:scheduled_run_id]) end def load_user @user = User.create_new_or_load_existing(params[:user]) end end As you can see, it doesn't take into account where the ScheduledRun instance has already reached capacity. Any help on this would be greatly appreciated.

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  • How do I avoid multiple key up/down/press events when holding a key?

    - by Rammay
    I'm creating a web front end to control a small robot. Ajax calls will be made on a keydown, to start the robot, and keyup to stop it. My problem is that when a key is held down the keyup, keydown, and keypress events seem to cycle continually. Does anybody know of a way to only have keydown fire when the key is first pressed and keyup to fire when it has been released?

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  • How to avoid links to map.root getting shortened?

    - by Guy C
    I have a Reports controller and various reports: http://localhost/reports/main/this_month http://localhost/reports/main/last_month http://localhost/reports/main/this_year I wanted http://localhost to default to http://localhost/reports/main/this_month. That is easy enough using map.root in my routes.rb. However when I do this any links to http://localhost/reports/main/this_month are now shortened to just http://localhost. I want the links to stay full

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  • How to avoid escaping by accident in PERL using system()?

    - by Brian
    I want to run some commands using the system() command, I do this way: execute_command_error("trash-put '/home/$filename'"); Where execute_command_error will report if there was an error with whatever system command it ran. I know I could just unlink the file using Perl commands, but I want to delete stuff using trash-put as it's a type of recycling program. My problem is that $filename will sometimes have apostrophes, quotes, and other weird characters in it that mess up the system command or Perl itself.

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  • Should we avoid to use Object as the input parameter/ output value of a method?

    - by developer.cyrus
    Take Java syntax as an example, though the question itself is language independent. If the following snippet takes an object MyAbstractEmailTemplate as input argument in the method setTemplate, the class MyGateway will then become tightly-coupled with the object MyAbstractEmailTemplate, which lessens the re-usability of the class MyGateway. A compromise is to use dependency-injection to ease the instantiation of MyAbstractEmailTemplate. This might solve the coupling problem to some extent, but the interface is still rigid, hardly providing enough ?exibility to other developers/ applications. So if we only use primitive data type (or even plain XML in web service) as the input/ output of a method, it seems the coupling problem no longer exists. So what do you think? public class MyGateway { protected MyAbstractEmailTemplate template; publoc void setTemplate(MyAbstractEmailTemplate template) { this.template = template; } }

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  • JQUERY common function library create script errors. How to avoid?

    - by Cesar Lopez
    Hi all, I am building a common function library but the functions inside need to reference different jquery files, which they may need to be referenced in some pages but not in others. When I called this common function library in one web page which is only going to use one function, and I don't reference the files need it for the other function, then it will create a script error. My question is if it would be possible to stop this script errors like... //This if statement is what I was thinking to stop going through if ($(".objectdate") != null){ //This is the function that is calling other jquery files and creates error. $(document).ready(function() { $(".objectdate").datepicker({ //Code inside. }); }); } Thanks.

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  • Is it good practice to avoid declaring a pointer to BOOL type in objective C?

    - by Krishnan
    I read this question in stackoverflow. The excerpt answer provided by bbum is below: The problem isn't the assignment, it is much more likely that you declared your instance variable to be BOOL *initialBroadcast;. There is no reason to declare the instance variable to be a pointer (at least not unless you really do need a C array of BOOLs).. Remove the * from the declaration. 1.Is there anything wrong in using a pointer variable even when I do not have to maintain an array of BOOLs? 2.I think even if avoiding them a good practice, it is not specific to objective-C and applies to all programming languages which has pointers. Please answer my questions.

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  • C++ Virtual keyword as away to avoid including code units.

    - by user394663
    Currently we have a body of code that allows service plugins which offer forms of communication to the core e.g tcp/ip, udp/ip, usb, etc... These service plugins feedback notifier class instances to the core for further processing. In the current implementation a service project (which is a separate dynamically linked library brought in at runtime by the core via dlopen and friends) will compile against the notifier.cpp file that resides in the core source code (a separate project). This gives access to the notifiers method implementations. This works perfectly no complaints. Two alternative options: 1. put the notifier method implementations in the header file. 2. declare the notifier methods virtual and delay binding until runtime. Avoiding the issues of computational overhead what are the impacts of option 2? Are there any other options available to us? Thanks

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  • SELECT SQL Variable - should i avoid using this syntax and always use SET?

    - by Sholom
    Hi All, This may look like a duplicate to here, but it's not. I am trying to get a best practice, not a technical answer (which i already (think) i know). New to SQL Server and trying to form good habits. I found a great explanation of the functional differences between SET @var = and SELECT @var = here: http://vyaskn.tripod.com/differences_between_set_and_select.htm To summarize what each has that the other hasn't (see source for examples): SET: ANSI and portable, recommended by Microsoft. SET @var = (SELECT column_name FROM table_name) fails when the select returns more then one value, eliminating the possibility of unpredictable results. SET @var = (SELECT column_name FROM table_name) will set @var to NULL if that's what SELECT column_name FROM table_name returned, thus never leaving @var at it's prior value. SELECT: Multiple variables can be set in one statement Can return multiple system variables set by the prior DML statement SELECT @var = column_name FROM table_name would set @var to (according to my testing) the last value returned by the select. This could be a feature or a bug. Behavior can be changed with SELECT @j = (SELECT column_name FROM table_name) syntax. Speed. Setting multiple variables with a single SELECT statement as opposed to multiple SET/SELECT statements is much quicker. He has a sample test to prove his point. If you could design a test to prove the otherwise, bring it on! So, what do i do? (Almost) always use SET @var =, using SELECT @var = is messy coding and not standard. OR Use SELECT @var = freely, it could accomplish more for me, unless the code is likely to be ported to another environment. Thanks

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  • How to avoid StaleObjectStateException when transaction updates thousands of entities?

    - by ThinkFloyd
    We are using Hibernate 3.6.0.Final with JPA 2 and Spring 3.0.5 for a large scale enterprise application running on tomcat 7 and MySQL 5.5. Most of the transactions in application, lives for less than a second and update 5-10 entities but in some use cases we need to update more than 10-20K entities in single transaction, which takes few minutes and hence more than 70% of times such transaction fails with StaleObjectStateException because some of those entities got updated by some other transaction. We generally maintain version column in all tables and in case of StaleObjectStateException we generally retry but since these longs transactions are anyways very long so if we keep on retrying then also I am not very sure that we'll be able to escape StaleObjectStateException. Also lot of activities keep updating these entities in busy hours so we cannot go with pessimistic approach because it can potentially halt many activities in system. Please suggest how to fix such long transaction issue because we cannot spawn thousands of independent and small transactions because we cannot afford messed up data in case of some failed & some successful transactions.

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