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  • URL Routing in Java

    - by Jack
    Coming from other web frameworks, I'm used to being able to map parts of a URL to method parameters. I know that web.xml provides a way to map an entire URL to a Servlet but is there a way to get more features out of this, such as mapping pieces of the URL to method parameters?

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  • Question about singleton property

    - by Jack
    I'm reading the java tutorial for enums located here and have a question: http://java.sun.com/j2se/1.5.0/docs/guide/language/enums.html#Card The part i'm confused about is as follows: "The Card class, above, contains a static factory that returns a deck, but there is no way to get an individual card from its rank and suit. Merely exposing the constructor would destroy the singleton property (that only a single instance of each card is allowed to exist). Here is how to write a static factory that preserves the singleton property, using a nested EnumMap: " Now as I understand, changing the original private "Card" constructor to public would allow us to instantiate an unlimited number of copies of a "Card" object with a given suit+rank. The solution as proposed was to create an EnumMap which would store four Maps (one for each suit), which themselves contained 13 Card objects with the rank as their keys. And so now if you wanted to retrieve a specific Card object from the deck, you would just call the "valueOf" method. My question now is, what's the prevent you with calling the valueOf method as many times as you like? Wouldn't that lead to the same problem as making the original private constructor public? Thanks.

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  • Are programming languages and methods ineffective? (assembler and C knowledge needed)

    - by b-gen-jack-o-neill
    Hi, for a long time, I am thinking and studying output of C language compiler in asemlber form, as well as CPU architecture. I know this may be silly to you, but it seems to me that something is very ineffective. Please, don´t be angry if I am wrong, and there is some reason I do not see for all these principles. I will be very glad if you tell me why is it designed this way. I actually trully believe I am wrong, I know the genius minds of people which get PCs together knew a reason to do so. What exactly, do you ask? I´ll tell you right away, I use C as a example: 1, Stack local scope memory allocation: So, typical local memory allocation uses stack. Just copy esp to ebp and than allocate all the memory via ebp. OK, I would understand this if you explicitly need allocate RAM by default stack values, but if I do understand it correctly, modern OS use paging as a translation layer between application and physical RAM, when adress you desire is further translated before reaching actuall RAM byte. So why don´t just say 0x00000000 is int a,0x00000004 is int b and so? And access them just by mov 0x00000000,#10? Becouse you wont actually access memory blocks 0x00000000 and 0x00000004 but those your OS set the paging tables to. Actually, since memory allocation by ebp and esp use indirect adressing, "my" way would be even faster. 2, Variable allocation duplicitly: When you run aaplication, Loader load its code into RAM. When you create variable, or string, compiler generates code that pushes these values on the top o stack when created in main. So there is actuall instruction for do so, and that actuall number in memory. So, there are 2 entries of the same value in RAM. One in fomr of instruction, second in form of actuall bytes in the RAM. But why? Why not to just when declaring variable count at which memory block it would be, than when used, just insert this memory location?

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  • C/C++ function definitions without assembly

    - by Jack
    Hi, I always thought that functions like printf() are in the last step defined using inline assembly. That deep into stdio.h is burried some asm code that actually tells CPU what to do. Something like in dos, first mov bagining of the string to some memory location or register and than call some int. But since x64 version of Visual Studio doesent support inline assembler at all, it made me think that there are really no assembler-defined functions in C/C++. So, please, how is for example printf() defined in C/C++ without using assembler code? What actually executes the right software interrupt? Thanks.

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  • How many keys are too many in memcached?

    - by jack
    I currently have about 650,000 items in memcached (430MB memory used) and the number is still increasing. It's expected to exceed 1,000,000 items before going flat. Current hit/miss ratio is 25:1 so the efficiency is pretty good. I just wanted to ask is one million items in memcached on single server too many? If no, how many is too many?

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  • Import Excel into Rails app

    - by Jack
    Hi, I am creating a small rails app for personal use and would like to be able to upload excel files to later be validated and added to the database. I had this working previously with csv files, but this has since become impractical. Does anyone know of a tutorial for using the roo or spreadsheet gem to upload the file, display the contents to the user and then add to the database (after validating)? I know this is quite specific, but I want to work through this step by step. All I have so far is an 'import' view: <% form_for :dump, :url=>{:controller=>"students", :action=>"student_import"}, :html => { :multipart => true } do |f| -%> Select an Excel File : <%= f.file_field :excel_file -%> <%= submit_tag 'Submit' -%> <% end -%> But have no idea how to access this uploaded file in the controller. Any suggestions/help would be welcomed. Thanks

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  • How to iterate over function arguments

    - by Jack
    I have a Python function accepting several string arguments def foo(a, b, c): and concatenating them in a string. I want to iterate over all function arguments to check they are not None. How it can be done? Is there a quick way to convert None to ""? Thanks.

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  • Best way to implement some type of ITaggable interface

    - by Jack
    I've got a program I'm creating that reports on another certain programs backup xml files. I've gotten to the point where I need to implement some type of ITaggable interface - but am unsure how to go about it code wise. My idea is that each item (BackupClient, BackupVersion, and BackupFile) should implement an ITaggable interface for highlighting old, out of date, or non-existent files in their HTML or Excel report. The user will be able to specify tags in the settings. My question is this, how can a user dynamically specify a "tag" such as File Date 3 days old? - Background Color = Red. Actually I guess my question is more, how can I, the programmer, implement this dynamically? I was thinking Expression trees, but am unsure this is the way to go as I havn't studied them much. I know my ITaggable interface would have methods such as AddTag(T tag), RemoveTag(T tag), but what exactly specifies the criteria for the tag to be added? I realize this may be subjective, and can be marked as wiki if need be, but I truly am stuck. Any input would be greatly helpful!

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  • Set focus on particular tab in IE and/or FireFox

    - by Jack Juiceson
    Hi all, I want to write an application that will monitor the content of all open tabs in IE / FireFox and trigger event once particular data is displayed in the tab. I would like to know if there is an API for IE/FF to set focus on particular TAB, so that once event is triggered I set focus on a relevant tab. Thanks in advance

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  • How can I execute a block of code exactly once in PHP?

    - by Jack
    I have one main.php file with a class definition. Other php files use this main.php file //main.php <?php class A{ } //I want to execute the following statements exactly once $a = new A(); /* Some code */ ?> I use main.php in other php files like //php1.php <?php require_once("main.php"); $b = new A(); /* Some code */ ?> Is there any statement in PHP like execute_once()? How do I solve this?

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  • How to handle Foreign Keys with Entity Framework

    - by Jack Marchetti
    I have two entities. Groups. Pools. A Group can create many pools. So I setup my Pool table to have a GroupID foreign key. My code: using (entity _db = new entity()) { Pool p = new Pool(); p.Name = "test"; p.Group.ID = "5"; _db.AddToPool(p); } This doesn't work. I get a null reference exception on p.Group. How do I go about creating a new "Pool" and associating a GroupID?

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  • Handling Session timeout in asp.net so all info. is aviable before create/update record

    - by Jack
    I'm having problem with some data missing in the record. I've a ASP.net web app that take some information from the user then create a record on the database. It's your typical CRUD app but I've noticed lately that some record are missing couple fields. Where they are null value. I think it might have been an Session issue. What's the best way to handle session time out in a typical CRUD app? Thanks

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  • Can you execute multiple statements in with a If statement?

    - by Jack Null
    This is my function: (defun MyFunction(input) (let ((NEWNUM (find input num))) (if (find input num) //if this (setq num NEWNUM) (FUNCT2) //then execute both of these (list 'not found)))) //else output this So after the if statment I want to be able to execute (setq num NEWNUM) and (FUNCT2). One to set a new variable and then the other to call a function. Any ideas on how to do this?

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  • How to call a PHP class member function from a Java file?

    - by Jack
    I am using PHP/Java bridge to run PHP scripts on the Tomcat server. Can someone point me to an example as to how to call my PHP scripts from a Java file. <?php class X{ //variables //functions } ?> Now I want to call the member functions of class X using its object via a Java file. How do I do this?

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  • Which controls are being used?

    - by Jack
    Are there any tools available that allow you to 'look' at any given application and show you which WinForm controls are being used in that application? I happen to have an app which I like the GUI of, and I want to use a similar structure in my own app. Instead of developing these controls myself, it may be easier to buy them, if only I can spot which are being used... Any suggestions?

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  • How to use git to download a particular tag?

    - by Jack BeNimble
    I'm trying to figure out how do download a particular tag of a git repository - it's one version behind the current version. I saw there was a tag for the previous version on the git web page, with object name of something long hex number. But the version name is "Tagged release 1.1.5" according the site. I tried a command like this (with names changed): git clone http://git.abc.net/git/abc.git my_abc And I did get something - a directory, a bunch of subdirectories, etc. If it's the whole repository, how do I get at the version I'm seeking? If not, how do I download that particular version?

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  • A 3-D grid of regularly spaced points

    - by Jack
    I want to create a list containing the 3-D coords of a grid of regularly spaced points, each as a 3-element tuple. I'm looking for advice on the most efficient way to do this. In C++ for instance, I simply loop over three nested loops, one for each coordinate. In Matlab, I would probably use the meshgrid function (which would do it in one command). I've read about meshgrid and mgrid in Python, and I've also read that using numpy's broadcasting rules is more efficient. It seems to me that using the zip function in combination with the numpy broadcast rules might be the most efficient way, but zip doesn't seem to be overloaded in numpy.

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