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  • rais belong_to which class to choose

    - by Small Wolf
    There is a model relation like this. class A belongs_to :ref_config,:class_name => 'User' end My question is : the A has a attribute named flag, now i want to create a function like this: if flag == 1, I want the class A like this belongs_to :ref_config,:class_name => 'Department and if flag == 2, i want the class A like this belongs_to :ref_config,:class_name => 'User' How can I implement the function Thank you!

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  • How do I create static instances of a class inside that class?

    - by wehas
    I have a class Color that holds values for the red, green, and blue channels of a color. The class constructor lets you create a new color by specifying values for the three channels. However, for convenience, I would also like to have some "premade" colors available for the programmer. For example instead of having something like DrawRectangle(new Color(1, 0, 0)); you would be able to say DrawRectangle(Color.Red); Where Color.Red is an instance of Color that lives inside the Color class. How can I declare these instances of Color inside the Color class? If there is a name for this type of technique I'd like to know it as I had no idea what search terms to use when I was looking for help online.

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  • Create Class objects based on type signature

    - by Andreas_D
    Class.forName(boolean.class.getName()); This doesn't work in Java - the virtual machine slaps you with a ClassNotFoundException. I was in need for something like that because I wanted to reflect methods based on Strings that included the method signatures, like public void doSomething(boolean yesWeCan, java.lang.String[] presidents); At the end I came up with a custom 'ClassFactory' which translates the type Strings to class objects. This factory includes a lot of handlers for primitive and array type values. The handler for array type objects is something like: if (isArrayOfObjects) { return Class.forName("L["+typeName.replace("[]", "")+";"); } My question is - have I missed something in the Java 1.5+ API that might do the trick?

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  • PHP - not sure how to ask - regarding variables and $_POST

    - by Phil
    I have a PHP form. The form works but I'm trying to test to see if a value other than the first item has been selected. I can't figure out how to write the If statement. $products = array( '' => 1, 'Item 2' => 2, 'Item 3' => 3, 'Item 4' => 4, 'Item 5' => 5, 'Item 6' => 6 ); $html = generateSelect('products', $products); function generateSelect($name = '', $options = array()) { $html = '<select name="'.$name.'">'; foreach ($options as $option => $value) { $html .= '<option value='.$value.'>'.$option.'</option>'; } $html .= '</select>'; return $html; } In my table, the drop down box is displayed: <tr> <td style="width:{$left_col_width}; text-align:left; vertical-align:center; padding:{$cell_padding}; font-weight:bold; {$product[3]}">{$product[0]}</td> <td style="text-align:left; vertical-align:top; padding:{$cell_padding};"><select name="{$product[1]}"> <option value="1"></option> <option value="2">Item 2</option> <option value="3">Item 3</option> <option value="4">Item 4</option> <option value="5">Item 5</option> <option value="6">Item 6</option> </select></td> </tr> I use the following if statement to check to see if someone has entered a phone number. if they have not entered a phone number, then the "Phone:" text turns red. How do I do an if statement similar to this to verify that someone has selected a product option from the drop down box? if(!empty($_POST['phone'])) { $phone[2] = clean_var($_POST['phone']); if (function_exists('htmlspecialchars')) $phone[2] = htmlspecialchars($phone[2], ENT_QUOTES); } else { $error = 1; $phone[3] = 'color:#d20128;'; } it seems simple but I can't figure it out.

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  • Accessing TextView from another class

    - by Jenny
    I've got my main startup class loading main.xml but I'm trying to figure out how to access the TextView from another class which is loading information from a database. I would like to publish that information to the TextView. So far I've not found any helpful examples on Google. EDIT: This is my class that is doing the Database work: import android.widget.TextView;import android.view.View; public class DBWork{ private View view; ... TextView tv = (TextView) view.findViewById(R.id.TextView01); tv.setText("TEXT ME") Yet, everytime I do that I get a nullpointerexception

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  • Writing Ruby Libraries - hiding methods from outside the module

    - by JP
    Hi all, I'm writing a Ruby library which has a module with a bunch of classes inside it. Many of these classes need to be usable and modifiable by calling scripts, but I don't want (some of) the initializers to be visible/callable: module MyLib class Control def initialize # They can use this end def do_stuff Helper.new('things') end end class Helper # Shouldn't be visible def initialize(what) @what = what end def shout @what end end end c = MyLib::Control.new h = c.do_stuff p h.shout # => "things" # ^ All of this is desired # v This is undesirable p MyLib::Helper.new('!') # => <MyLib::Helper @what='!'> If it's a simple thing, then I'd also appreciate the generated RDoc not even include the .new method for the Helper class either. Any ideas? Thanks for reading!

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  • Why should Java ThreadLocal variables be static

    - by kellyfj
    I was reading that JavaDoc for Threadlocal here http://java.sun.com/j2se/1.5.0/docs/api/java/lang/ThreadLocal.html and it says "ThreadLocal instances are typically private static fields in classes that wish to associate state with a thread (e.g., a user ID or Transaction ID). " But my question is why did they choose to make it static (typically) - it makes it a bit confusing to have "per thread" state but its static?

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  • Transparently storing class state without exposing implementation

    - by RoToRa
    I have a model (MVC) class whose internal state (which basically contains of private int fields) I want to store. The program is running on Android (for now) so I need to store the in a Bundle, but I'll be using the same class later in a desktop application where I'll have to store the state some other way, so I can't reference Bundle directly in my class. So my question is: What is the best way to store (and retrieve) the state of a class without exposing it's implementation? The best I could think of removing the private access modifier so that the fields become package accessible and create read/write helper classes in the same package, but that somehow seems wrong.

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  • Maven: Variables are not replaced in installed and deployed POM

    - by mmuthu
    We have been trying to migrate our multi-module projects to maven. I have been struggling with the maven install plugin bug "http://jira.codehaus.org/browse/MNG-2971". I have written a Java program which can find and replace the expressions using my settings.xml and POM in my local repository view. As a result all of my parent POM's are having a additional phase in the build process. What i'm doing is that i have attached a goal which will run my Java program during "validate" phase. I think this is a not a good idea instead i would have asked individuals to run the program on their local repository on their own. What i'm asking here is that the best way to work around the "install" plugin issue (MNG-2971). I searched through the net but i could not locate such work around.

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  • Inlining an array of non-default constructible objects in a C++ class

    - by porgarmingduod
    C++ doesn't allow a class containing an array of items that are not default constructible: class Gordian { public: int member; Gordian(int must_have_variable) : member(must_have_variable) {} }; class Knot { Gordian* pointer_array[8]; // Sure, this works. Gordian inlined_array[8]; // Won't compile. Can't be initialized. }; As even beginner C++ users know, the language guarantees that all members are initialized when constructing a class. And it doesn't trust the user to initialize everything in the constructor - one has to provide valid arguments to the constructors of all members before the body of the constructor even starts. Generally, that's a great idea as far as I'm concerned, but I've come across a situation where it would be a lot easier if I could actually have an array of non-default constructible objects. The obvious solution: Have an array of pointers to the objects. This is not optimal in my case, as I am using shared memory. It would force me to do extra allocation from an already contended resource (that is, the shared memory). The entire reason I want to have the array inlined in the object is to reduce the number of allocations. This is a situation where I would be willing to use a hack, even an ugly one, provided it works. One possible hack I am thinking about would be: class Knot { public: struct dummy { char padding[sizeof(Gordian)]; }; dummy inlined_array[8]; Gordian* get(int index) { return reinterpret_cast<Gordian*>(&inlined_array[index]); } Knot() { for (int x = 0; x != 8; x++) { new (get(x)) Gordian(x*x); } } }; Sure, it compiles, but I'm not exactly an experienced C++ programmer. That is, I couldn't possibly trust my hacks less. So, the questions: 1) Does the hack I came up with seem workable? What are the issues? (I'm mainly concerned with C++0x on newer versions of GCC). 2) Is there a better way to inline an array of non-default constructible objects in a class?

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  • Apply CSS class to invalid controls on web form

    - by user137639
    I need to apply a css class to invalid controls on a web form. I'd like to make it a resusable class. This is what I have so far: public class Validation { public static void ApplyInvalidClass(Page page, string className) { foreach (System.Web.UI.WebControls.BaseValidator bv in page.Validators) { if (!bv.IsValid) { Control ctrl = page.FindControl(bv.ControlToValidate); if (ctrl != null) { if (ctrl is TextBox) { TextBox txt = ctrl as TextBox; txt.CssClass = "invalid"; } if (ctrl is DropDownList) { DropDownList ddl = ctrl as DropDownList; ddl.CssClass = "invalid"; } if (ctrl is CheckBox) { CheckBox cb = ctrl as CheckBox; cb.CssClass = "invalid"; } if (ctrl is HtmlGenericControl) { HtmlGenericControl html = ctrl as HtmlGenericControl; html.Attributes.Add("class", className); } } } } } } The problem is what I call this on a .Net user control, I guess because I'm passing in Page, page.FindControl(bv.ControlToValidate) is always null. Is there a better way to do this?

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  • How to get a list of users for all instance's databases

    - by stee1rat
    I guess the procedure should be something like this: declare @db varchar(100) declare @user varchar(100) declare c cursor for select name from sys.sysdatabases open c fetch next from c into @db while @@fetch_status = 0 begin print @db exec ('use ' + @db) declare u cursor for select name from sys.sysusers where issqlrole <> 1 and hasdbaccess <> 0 and isntname <> 1 open u fetch next from u into @user while @@fetch_status = 0 begin print @user fetch next from u into @user end print '--------------------------------------------------' close u deallocate u fetch next from c into @db end close c deallocate c But the problem is that exec ('use ' + @db) doesn't work. And i always get user list of currently chosen database. How should i fix that? P.S.: I want this code to work on both 2000 and 2005 sql servers.

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  • Create variables for unknown amount of arguments?

    - by user347600
    Working on an rsync script and the portion below is in a for loop. What I want to achieve is assign a variable to every arguement after 3. Just confused if I need to create another loop for that or not: #1: name name=$1 #2: ip ip=$2 #3: user user=$3 #4+: folder exlusion #any lines higher than 3 will be created as exlcude folders ex[ARG_NUMBER]=

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  • C++ abstract class template + type-specific subclass = trouble with linker

    - by user333279
    Hi there, The project in question is about different endpoints communicating with each other. An endpoint sends events (beyond the scope of the current problem) and can process incoming events. Each event is represented in a generic object as follows: #pragma interface ... // some includes template<typename T> class Event { public: Event(int senderId, Type type, T payload); // Type is an enum Event(int senderId, Type type, int priority, T payload); virtual ~Event(); virtual int getSenderId(); virtual int getPriority(); virtual T getPayload(); void setPriority(const int priority); protected: const int senderId; const Type type; const T payload; int priority; }; It has its implementing class with #pragma implementation tag. An endpoint is defined as follows: #pragma interface #include "Event.h" template<typename T> class AbstractEndPoint { public: AbstractEndPoint(int id); virtual ~AbstractEndPoint(); virtual int getId(); virtual void processEvent(Event<T> event) = 0; protected: const int id; }; It has its implementing class too, but only the constructor, destructor and getId() are defined. The idea is to create concrete endpoints for each different payload type. Therefore I have different payload objects and specific event classes for each type, e.g. Event<TelegramFormatA>, Event<TelegramFormatB> and ConcreteEndPoint for TelegramFormatA, ConcreteEndPoint for TelegramFormatB respectively. The latter classes are defined as class ConcreteEndPoint : AbstractEndPoint<TelegramFormatA> { ... } I'm using g++ 4.4.3 and ld 2.19. Everything compiles nicely, but the linker complaints about undefined references to type-specific event classes, like Event<TelegramFormatA>::Event(....) . I tried explicit instantiation using template class AbstractEndPoint<TelegramFormatA>; but couldn't get past the aforementioned linker errors. Any ideas would be appreciated.

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  • How to compare two char* variables

    - by davit-datuashvili
    Suppose we have the following method (it is in c code): const char *bitap_search(const char *text, const char *pattern) My question is how can I compare text and pattern if they are char? This method is like a substring problem but I am confused a bit can I write in term of char such code? if (text[i]==pattern[i])? look i am interesting at this algorithm in java http://en.wikipedia.org/wiki/Bitap_algorithm how implement this in java? R = malloc((k+1) * sizeof *R); and please help me to translate this code in java

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  • Reading Connection String from a class Library

    - by devnet247
    Hi all I have a .net class library 2.0 with an app.config with a connectionString section. I have 01 Method that this class library exposes " string GetConnectionString(string name) However even though the app.config in this class library has 3 connstrings it does not read this config.exe.How can I make it read the app.config that resides withing this dll? Again, Usually you will have a web or windows app with a config and it will all work. Mine is a special case I need to read the connectionstring within this class library. How can I do it? thanks a lot

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  • regular expressions for class name

    - by user576701
    i need a regular expressions string to get all anchor tags in a page with a specific css class name, in c#/vb.net this is what i got so far "<a.*?href=""(.*?)"".*?>(.*?)</a>" but my attempts to add "class=name" isnt working, also is it possible to find links where the class name appears either before or after the href with one expression ? i am familiar with 3rd party html libraries, but thats an overkill for what i have in mind, so is the webbrowser control.

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