Search Results

Search found 25521 results on 1021 pages for 'static objects'.

Page 457/1021 | < Previous Page | 453 454 455 456 457 458 459 460 461 462 463 464  | Next Page >

  • What exactly is a reentrant function?

    - by eSKay
    Most of the times, the definition of reentrance is quoted from Wikipedia: A computer program or routine is described as reentrant if it can be safely called again before its previous invocation has been completed (i.e it can be safely executed concurrently). To be reentrant, a computer program or routine: Must hold no static (or global) non-constant data. Must not return the address to static (or global) non-constant data. Must work only on the data provided to it by the caller. Must not rely on locks to singleton resources. Must not modify its own code (unless executing in its own unique thread storage) Must not call non-reentrant computer programs or routines. How is safely defined? If a program can be safely executed concurrently, does it always mean that it is reentrant? What exactly is the common thread between the six points mentioned that I should keep in mind while checking my code for reentrant capabilities? Also, Are all recursive functions reentrant? Are all thread-safe functions reentrant? Are all recursive and thread-safe functions reentrant? While writing this question, one thing comes to mind: Are the terms like reentrance and thread safety absolute at all i.e. do they have fixed concrete definations? For, if they are not, this question is not very meaningful. Thanks!

    Read the article

  • What is the best way to handle the Connections to MySql from c#

    - by srk
    I am working on a c# application which connects to MySql server. There are about 20 functions which will connect to database. This application will be deployed in 200 over machines. I am using the below code to connect to my database which is identical for all the functions. The problem is, i can some connections were not closed and still alive when deployed in 200 over machines. Connection String : <add key="Con_Admin" value="server=test-dbserver; database=test_admindb; uid=admin; password=1Password; Use Procedure Bodies=false;" /> Declaration of the connection string Globally in application [Global.cs] : public static MySqlConnection myConn_Instructor = new MySqlConnection(ConfigurationSettings.AppSettings["Con_Admin"]); Function to query database : public static DataSet CheckLogin_Instructor(string UserName, string Password) { DataSet dsValue = new DataSet(); //MySqlConnection myConn = new MySqlConnection(ConfigurationSettings.AppSettings["Con_Admin"]); try { string Query = "SELECT accounts.str_nric AS Nric, accounts.str_password AS `Password`," + " FROM accounts " + " WHERE accounts.str_nric = '" + UserName + "' AND accounts.str_password = '" + Password + "\'"; MySqlCommand cmd = new MySqlCommand(Query, Global.myConn_Instructor); MySqlDataAdapter da = new MySqlDataAdapter(); if (Global.myConn_Instructor.State == ConnectionState.Closed) { Global.myConn_Instructor.Open(); } cmd.ExecuteScalar(); da.SelectCommand = cmd; da.Fill(dsValue); Global.myConn_Instructor.Close(); } catch (Exception ex) { Global.myConn_Instructor.Close(); ExceptionHandler.writeToLogFile(System.Environment.NewLine + "Target : " + ex.TargetSite.ToString() + System.Environment.NewLine + "Message : " + ex.Message.ToString() + System.Environment.NewLine + "Stack : " + ex.StackTrace.ToString()); } return dsValue; }

    Read the article

  • Applying the Decorator Pattern to Forms

    - by devoured elysium
    I am trying to apply the Decorator Design Pattern to the following situation: I have 3 different kind of forms: Green, Yellow, Red. Now, each of those forms can have different set of attributes. They can have a minimize box disabled, a maximized box disabled and they can be always on top. I tried to model this the following way: Form <---------------------------------------FormDecorator /\ /\ |---------|-----------| |----------------------|-----------------| GreenForm YellowForm RedForm MinimizeButtonDisabled MaximizedButtonDisabled AlwaysOnTop Here is my GreenForm code: public class GreenForm : Form { public GreenForm() { this.BackColor = Color.GreenYellow; } public override sealed Color BackColor { get { return base.BackColor; } set { base.BackColor = value; } } } FormDecorator: public abstract class FormDecorator : Form { private Form _decoratorForm; protected FormDecorator(Form decoratorForm) { this._decoratorForm = decoratorForm; } } and finally NoMaximizeDecorator: public class NoMaximizeDecorator : FormDecorator { public NoMaximizeDecorator(Form decoratorForm) : base(decoratorForm) { this.MaximizeBox = false; } } So here is the running code: static void Main() { Application.EnableVisualStyles(); Application.SetCompatibleTextRenderingDefault(false); Application.Run(CreateForm()); } static Form CreateForm() { Form form = new GreenForm(); form = new NoMaximizeDecorator(form); form = new NoMinimizeDecorator(form); return form; } The problem is that I get a form that isn't green and that still allows me to maximize it. It is only taking in consideration the NoMinimizeDecorator form. I do comprehend why this happens but I'm having trouble understanding how to make this work with this Pattern. I know probably there are better ways of achieving what I want. I made this example as an attempt to apply the Decorator Pattern to something. Maybe this wasn't the best pattern I could have used(if one, at all) to this kind of scenario. Is there any other pattern more suitable than the Decorator to accomplish this? Am I doing something wrong when trying to implement the Decorator Pattern? Thanks

    Read the article

  • SFINAE + sizeof = detect if expression compiles

    - by FredOverflow
    I just found out how to check if operator<< is provided for a type. template<class T> T& lvalue_of_type(); template<class T> T rvalue_of_type(); template<class T> struct is_printable { template<class U> static char test(char(*)[sizeof( lvalue_of_type<std::ostream>() << rvalue_of_type<U>() )]); template<class U> static long test(...); enum { value = 1 == sizeof test<T>(0) }; typedef boost::integral_constant<bool, value> type; }; Is this trick well-known, or have I just won the metaprogramming Nobel prize? ;) EDIT: I made the code simpler to understand and easier to adapt with two global function template declarations lvalue_of_type and rvalue_of_type.

    Read the article

  • What's wrong with my HtmlHelper?

    - by Dejan.S
    I done a htmlhelper but I can not get it to work tho. I did like I seen on different tutorials. my MenuItemHelper static Class public static string MenuItem(this HtmlHelper helper, string linkText, string actionName, string controllerName) { var currentControllerName = (string)helper.ViewContext.RouteData.Values["controller"]; var currentActionName = (string)helper.ViewContext.RouteData.Values["action"]; var sb = new StringBuilder(); if (currentControllerName.Equals(controllerName, StringComparison.CurrentCultureIgnoreCase) && currentActionName.Equals(actionName, StringComparison.CurrentCultureIgnoreCase)) sb.Append("<li class=\"selected\">"); else sb.Append("<li>"); sb.Append(helper.ActionLink(linkText, actionName, controllerName)); sb.Append("</li>"); return sb.ToString(); } import namespace <%@ Import Namespace="MYAPP.Web.App.Helpers" %> Implementation on my master.page <%= Html.MenuItem("TEST LINK", "About", "Site") %> Errormessage I get Method not found: 'System.String System.Web.Mvc.Html.LinkExtensions.ActionLink(System.Web.Mvc.HtmlHelper, System.String, System.String, System.String)

    Read the article

  • How to hide certain elements on a page using jQuery

    - by Ankur
    I am trying to implement something that is similar to a faceted search. My data is a series of objects and relationships. The idea is that you click an object (in this case "95 Theses" and then the possibly relationships are displayed, in this case "author" and clicking the relationship shows the object that matches the relationship, in this case "Martin Luther". My clicking of objects and relationsips (predicates) works fine. What I need to do is allow users to click an object or relationship and have all those that extend from it removed. This is what I thought of adding when a object or relationship 'tag' is clicked (every time I add another object or relationship I increment the global attribute called 'level'): if($(".objHolder,. preHolder").filter("[level>'"+level+"']").filter("[holderId='"+holderId+"']").length) { $(".objHolder,. preHolder").filter("[level>'"+level+"']").filter("[holderId='"+holderId+"']").remove(); } <table border="0" cellpadding="4" cellspacing="2"> <tbody><tr> <td class="objHolder" objid="1" holderid="1" level="1"> <table border="0" cellpadding="4" cellspacing="2"> <tbody><tr class="objItemRow" objid="1" holderid="1" level="1"> <td class="objItem" objid="1" holderid="1" level="2" bgcolor="#eeeeee" nowrap="nowrap">95 Theses</td> </tr></tbody> </table></td> <td><img src="images/right.jpg" alt="" height="10" width="16"></td> <td class="preHolder" level="2" holderid="1"> <table border="0" cellpadding="4" cellspacing="2"><tbody> <tr><td class="preItem" level="3" subid="1" preid="1" holderid="1" bgcolor="#eeeeee" nowrap="nowrap">author</td></tr> </tbody></table></td> <td><img src="images/right.jpg" alt="" height="10" width="16"></td> <td class="objHolder" level="3" holderid="1"> <table border="0" cellpadding="4" cellspacing="2"><tbody><tr><td class="objItem" level="4" objid="3" holderid="1" bgcolor="#eeeeee" nowrap="nowrap">Martin Luther</td></tr></tbody></table> </td> </tr></tbody> </table>

    Read the article

  • f# interactive System.OutOfMemoryException

    - by user343550
    f# interactive throws System.OutOfMemoryException when loading large objects into memory. Exception is thrown at approximately 1.3 gigs. Data set is 2.2 gigs, and loads fine in debugger mode. Using VS2008 with April 2010 CTP This is mostly a java library that is being used via ikvmc, but if that were an issue, it shouldn't be running in the debugger either.

    Read the article

  • ahow can I resolve Django Error: str' object has no attribute 'autoescape'?

    - by Angelbit
    Hi have tried to create a inclusion tag on Django but don't work and return str' object has no attribute 'autoescape' this is the code of custom tag: from django import template from quotes.models import Quotes register = template.Library() def show_quote(): quote = Quotes.objects.values('quote', 'author').get(id=0) return {'quote': quote['quote']} register.inclusion_tag('quotes.html')(show_quote) EDIT: Quote class from django.db import models class Quotes(models.Model): quote = models.CharField(max_length=255) author = models.CharField(max_length=100) class Meta: db_table = 'quotes' quotes.html <blockquote id="quotes">{{ quote }}</blockquote>

    Read the article

  • Zend Framework - Can view helpers be user inside of partials?

    - by Bob Spryn
    Working on implementing view helpers and partials to create a group of reusable display objects. Previously addressed in my question here: http://stackoverflow.com/questions/2389531/zend-framework-when-to-use-viewscripts-partials-vs-view-helpers Wondering if partials can call view helpers of their own, and if they can whether those helpers will have access to the original view (since the partials don't).

    Read the article

  • Java. Best procedure to de-serialize a Java generic object?

    - by Jake
    What is the best procedure for storing and retrieving, using native Java serialization, generic objects like ArrayList<String>? Edit: To clarify. When I serialize an object of type ArrayList<String> I'd like to de-serialize to the same type of object. However, I know of no way to cast back to this generic object without causing warnings.

    Read the article

  • how to call include

    - by user276640
    i have 3 tables with such relationship table1-table2-table3 in code i call include("table2"). but how can i call include table3 so i can access to properties of objects table3? if i call include("table3") it show error A specified Include path is not valid

    Read the article

  • Accessing the value of an input element with XPath in an XSLT

    - by asymmetric
    Hi! I'm developing a web app that has a button that triggers an XSLT transformation of the document DOM, with a stylesheet fetched via AJAX. Here's a portion of the HTML: <html> <head> <title>Static Javascript-based XMR Form Creator</title> </head> <body> <h1 id="title">Static Javascript-based XMR Form Creator</h1> <div class="opt_block" id="main_opts"> Form name <input type="text" id="form_name" /> Form cols <input type="text" id="form_cols" size="3" maxlength="3" /> </div> <button id="generate">Generate source</button> <textarea rows="20" cols="50" id="xmr_source" ></textarea> </body> Inside the stylesheet, I want to access the value attribute of the first input field, the one with id form_name. The XSLT looks like this: <xsl:template match="/html/body/div[@id = 'main_opts']" > <form> <xsl:attribute name="fname"> <xsl:value-of select="input[@id = 'form_name']/@value" /> </xsl:attribute> </form> </xsl:template> The problem is that the XPath that should do the work: <xsl:value-of select="input[@id = 'form_name']/@value" /> returns nothing. Can anyone help?

    Read the article

  • Python's JSON module doesn't use __get__?

    - by Matt
    When I serialize a list of objects with a custom __get__ method, __get__ is not called and the raw (unprocessed by custom __get__) value from __set__ is used. How does Python's json module iterate over an item? Note: if I iterate over the list before serializing, the correct value returned by __get__ is used.

    Read the article

  • PDO using singleton stored as class properity

    - by Misiur
    Hi again. OOP drives me crazy. I can't move PDO to work. Here's my DB class: class DB extends PDO { public function &instance($dsn, $username = null, $password = null, $driver_options = array()) { static $instance = null; if($instance === null) { try { $instance = new self($dsn, $username, $password, $driver_options); } catch(PDOException $e) { throw new DBException($e->getMessage()); } } return $instance; } } It's okay when i do something like this: try { $db = new DB(DB_TYPE.':host='.DB_HOST.';dbname='.DB_NAME, DB_USER, DB_PASS); } catch(DBException $e) { echo $e->getMessage(); } But this: try { $db = DB::instance(DB_TYPE.':host='.DB_HOST.';dbname='.DB_NAME, DB_USER, DB_PASS); } catch(DBException $e) { echo $e->getMessage(); } Does nothing. I mean, even when I use wrong password/username, I don't get any exception. Second thing - I have class which is "heart" of my site: class Core { static private $instance; public $db; public function __construct() { if(!self::$instance) { $this->db = DB::instance(DB_TYPE.':hpost='.DB_HOST.';dbname='.DB_NAME, DB_USER, DB_PASS); } return self::$instance; } private function __clone() { } } I've tried to use "new DB" inside class, but this: $r = $core->db->query("SELECT * FROM me_config"); print_r($r->fetch()); Return nothing. $sql = "SELECT * FROM me_config"; print_r($core->db->query($sql)); I get: PDOStatement Object ( [queryString] => SELECT * FROM me_config ) I'm really confused, what am I doing wrong?

    Read the article

  • C# SQL: What is the best way to implement a dynamic table?

    - by SirMoreno
    I want to allow the user to add columns to a table in the UI. The UI: Columns Name:__ Columns Type: Number/String/Date My Question is how to build the SQL tables and C# objects so the implementation will be efficient and scalable. My thought is to build two SQL tables: TBL 1 - ColumnsDefinition: ColId, ColName, ColType[Text] TBL 2 - ColumnsValues: RowId, ColId, Value [Text] I want the solution to be efficient in DB space, and I want to allow the user to sort the dynamic columns. I work on .NET 3.5 MSSQL 2008. Thanks.

    Read the article

  • Gaining access to jndi environment variables within a Tomcat LifecycleListener

    - by rmarimon
    I'm using a LifecycleListener in tomcat to initialize some objects required by contexts in my web server. Within LifecycleListener I would like to have access to GlobalNamingResources Environment variables to keep the configuration for the server inside the server.xml file. When trying various approaches I get the following error: javax.naming.NameNotFoundException: Name java:comp is not bound in this Context I'm assuming that the jndi is not initialized by this stage of the server startup process. Any ideas on how to tackle this?

    Read the article

  • Extend and Overload MS and Point Types

    - by dr d b karron
    Do I have make my own Point and Vector types to overload them ? Why does this not work ? namespace System . windows { public partial struct Point : IFormattable { public static Point operator * ( Point P , double D ) { Point Po = new Point ( ); return Po; } } } namespace SilverlightApplication36 { public partial class MainPage : UserControl { public static void ShrinkingRectangle ( WriteableBitmap wBM , int x1 , int y1 , int x2 , int y2 , Color C ) { wBM . DrawRectangle ( x1 , y1 , x2 , y2 , Colors . Red ); Point Center = Mean ( x1 , y1 , x2 , y2 ); wBM . SetPixel ( Center , Colors.Blue , 3 ); Point P1 = new Point ( x1 , y1 ); Point P2 = new Point ( x1 , y2 ); Point P3 = new Point ( x1 , y2 ); Point P4 = new Point ( x2 , y1 ); const int Steps = 10; for ( int i = 0 ; i < Steps ; i++ ) { double iF = (double)(i+1) / (double)Steps; double jF = ( 1.0 - iF ); Point P11 = **P1 * jF;** } }

    Read the article

  • Instance caching in Objective C

    - by zoul
    Hello! I want to cache the instances of a certain class. The class keeps a dictionary of all its instances and when somebody requests a new instance, the class tries to satisfy the request from the cache first. There is a small problem with memory management though: The dictionary cache retains the inserted objects, so that they never get deallocated. I do want them to get deallocated, so that I had to overload the release method and when the retain count drops to one, I can remove the instance from cache and let it get deallocated. This works, but I am not comfortable mucking around the release method and find the solution overly complicated. I thought I could use some hashing class that does not retain the objects it stores. Is there such? The idea is that when the last user of a certain instance releases it, the instance would automatically disappear from the cache. NSHashTable seems to be what I am looking for, but the documentation talks about “supporting weak relationships in a garbage-collected environment.” Does it also work without garbage collection? Clarification: I cannot afford to keep the instances in memory unless somebody really needs them, that is why I want to purge the instance from the cache when the last “real” user releases it. Better solution: This was on the iPhone, I wanted to cache some textures and on the other hand I wanted to free them from memory as soon as the last real holder released them. The easier way to code this is through another class (let’s call it TextureManager). This class manages the texture instances and caches them, so that subsequent calls for texture with the same name are served from the cache. There is no need to purge the cache immediately as the last user releases the texture. We can simply keep the texture cached in memory and when the device gets short on memory, we receive the low memory warning and can purge the cache. This is a better solution, because the caching stuff does not pollute the Texture class, we do not have to mess with release and there is even a higher chance for cache hits. The TextureManager can be abstracted into a ResourceManager, so that it can cache other data, not only textures.

    Read the article

  • Async WebRequest Timeout Windows Phone 7

    - by Tyler
    Hi All, I'm wondering what the "right" way of timing out an HttpWebRequest is on Windows Phone7? I've been reading about ThreadPool.RegisterWaitForSingleObject() but this can't be used as WaitHandles throw a Not implemented exception at run time. I've also been looking at ManualReset events but A) Don't understand them properly and B) Don't understand how blocking the calling thread is an acceptable way to implement a time out on an Async request. Here's my existing code sans timeout, can someone please show me how I would add a timeout to this? public static void Get(Uri requestUri, HttpResponseReceived httpResponseReceivedCallback, ICredentials credentials, object userState, bool getResponseAsString = true, bool getResponseAsBytes = false) { var httpWebRequest = (HttpWebRequest)WebRequest.Create(requestUri); httpWebRequest.Method = "GET"; httpWebRequest.Credentials = credentials; var httpClientRequestState = new JsonHttpClientRequestState(null, userState, httpResponseReceivedCallback, httpWebRequest, getResponseAsString, getResponseAsBytes); httpWebRequest.BeginGetResponse(ResponseReceived, httpClientRequestState); } private static void ResponseReceived(IAsyncResult asyncResult) { var httpClientRequestState = asyncResult.AsyncState as JsonHttpClientRequestState; Debug.Assert(httpClientRequestState != null, "httpClientRequestState cannot be null. Fatal error."); try { var webResponse = (HttpWebResponse)httpClientRequestState.HttpWebRequest.EndGetResponse(asyncResult); } }

    Read the article

  • Attempted to render a circle in opengl es 1.1, renders as oval

    - by eipxen
    Hi all, I attempted to render a circle in opengl es 1.1 as a test before building a larger program, but it renders as an oval. Here is the code I use to generate and render my vertices: static const int numVerts = 40; static GLfloat myFirstCircle[82]; myFirstCircle[0] = 0.0f; myFirstCircle[1] = 0.0f; for (int i = 2; i < (numVerts+1)*2; i+=2) { myFirstCircle[i] = .5 * cosf(i*2*3.14159/numVerts); myFirstCircle[i+1] = .5 * sinf(i*2*3.14159/numVerts); } glVertexPointer(2, GL_FLOAT, 0, myFirstCircle); glEnableClientState(GL_VERTEX_ARRAY); glDrawArrays(GL_TRIANGLE_FAN, 0, 22); I'm still somewhat new to this system, so I may have a silly error that I do not see, but it seems to me like this should generate 40 vertices on a circle of radius .5. When it renders, the shape on screen appears to be an oval, significantly taller than it is wide. My question is thus: why is my circle rendering this way, and what could I do to fix it? This is the first question on stackoverflow, so I'm not sure how to share an image of my output.

    Read the article

  • Linq - How to collect Anonymous Type as Result for a Function

    - by GibboK
    I use c# 4 asp.net and EF 4. I'm precompiling a query, the result should be a collection of Anonymous Type. At the moment I use this code. public static readonly Func<CmsConnectionStringEntityDataModel, string, dynamic> queryContentsList = CompiledQuery.Compile<CmsConnectionStringEntityDataModel, string, dynamic> ( (ctx, TypeContent) => ctx.CmsContents.Where(c => c.TypeContent == TypeContent & c.IsPublished == true & c.IsDeleted == false) .Select(cnt => new { cnt.Title, cnt.TitleUrl, cnt.ContentId, cnt.TypeContent, cnt.Summary } ) .OrderByDescending(c => c.ContentId)); I suspect the RETURN for the FUNCTION Dynamic does not work properly and I get this error Sequence contains more than one element enter code here. I suppose I need to return for my function a Collection of Anonymous Types... Do you have any idea how to do it? What I'm doing wrong? Please post a sample of code thanks! Update: public class ConcTypeContents { public string Title { get; set; } public string TitleUrl { get; set; } public int ContentId { get; set; } public string TypeContent { get; set; } public string Summary { get; set; } } public static readonly Func<CmsConnectionStringEntityDataModel, string, ConcTypeContents> queryContentsList = CompiledQuery.Compile<CmsConnectionStringEntityDataModel, string, ConcTypeContents>( (ctx, TypeContent) => ctx.CmsContents.Where(c => c.TypeContent == TypeContent & c.IsPublished == true & c.IsDeleted == false) .Select(cnt => new ConcTypeContents { cnt.Title, cnt.TitleUrl, cnt.ContentId, cnt.TypeContent, cnt.Summary }).OrderByDescending(c => c.ContentId));

    Read the article

  • Schema to support dynamic properties

    - by Johan Fredrik Varen
    Hi people. I'm working on an editor that enables its users to create "object" definitions in real-time. A definition can contain zero or more properties. A property has a name a type. Once a definition is created, a user can create an object of that definition and set the property values of that object. So by the click of a mouse-button, the user should ie. be able to create a new definition called "Bicycle", and add the property "Size" of type "Numeric". Then another property called "Name" of type "Text", and then another property called "Price" of type "Numeric". Once that is done, the user should be able to create a couple of "Bicycle" objects and fill in the "Name" and "Price" property values of each bike. Now, I've seen this feature in several software products, so it must be a well-known concept. My problem started when I sat down and tried to come up with a DB schema to support this data structure, because I want the property values to be stored using the appropriate column types. Ie. a numeric property value is stored as, say, an INT in the database, and a textual property value is stored as VARCHAR. First, I need a table that will hold all my object definitions: Table obj_defs id | name | ---------------- 1 | "Bicycle" | 2 | "Book" | Then I need a table for holding what sort of properties each object definition should have: Table prop_defs id | obj_def_id | name | type | ------------------------------------ 1 | 1 | "Size" | ? | 2 | 1 | "Name" | ? | 3 | 1 | "Price" | ? | 4 | 2 | "Title" | ? | 5 | 2 | "Author" | ? | 6 | 2 | "ISBN" | ? | I would also need a table that holds each object: Table objects id | created | updated | ------------------------------ 1 | 2011-05-14 | 2011-06-15 | 2 | 2011-05-14 | 2011-06-15 | 3 | 2011-05-14 | 2011-06-15 | Finally, I need a table that will hold the actual property values of each object, and one solution is for this table to have one column for each possible value type, such as this: Table prop_vals id | prop_def_id | object_id | numeric | textual | boolean | ------------------------------------------------------------ 1 | 1 | 1 | 27 | | | 2 | 2 | 1 | | "Trek" | | 3 | 3 | 1 | 1249 | | | 4 | 1 | 2 | 26 | | | 5 | 2 | 2 | | "GT" | | 6 | 3 | 2 | 159 | | | 7 | 4 | 3 | | "It" | | 8 | 5 | 3 | | "King" | | 9 | 6 | 4 | 9 | | | If I implemented this schema, what would the "type" column of the prop_defs table hold? Integers that each map to a column name, varchars that simply hold the column name? Any other possibilities? Would a stored procedure help me out here in some way? And what would the SQL for fetching the "name" property of object 2 look like?

    Read the article

< Previous Page | 453 454 455 456 457 458 459 460 461 462 463 464  | Next Page >