Search Results

Search found 31491 results on 1260 pages for 'simple talk'.

Page 804/1260 | < Previous Page | 800 801 802 803 804 805 806 807 808 809 810 811  | Next Page >

  • What mutex/locking/waiting mechanism to use when writing a Chat application with Tornado Web Framewo

    - by user272973
    We're implementing a Chat server using Tornado. The premise is simple, a user makes open an HTTP ajax connection to the Tornado server, and the Tornado server answers only when a new message appears in the chat-room. Whenever the connection closes, regardless if a new message came in or an error/timeout occurred, the client reopens the connection. Looking at Tornado, the question arises of what library can we use to allow us to have these calls wait on some central object that would signal them - A_NEW_MESSAGE_HAS_ARRIVED_ITS_TIME_TO_SEND_BACK_SOME_DATA. To describe this in Win32 terms, each async call would be represented as a thread that would be hanging on a WaitForSingleObject(...) on some central Mutex/Event/etc. We will be operating in a standard Python environment (Tornado), is there something built-in we can use, do we need an external library/server, is there something Tornado recommends? Thanks

    Read the article

  • etree.findall: 'OR'-lookup?

    - by piquadrat
    I want to find all stylesheet definitions in a XHTML file with lxml.etree.findall. This could be as simple as elems = tree.findall('link[@rel="stylesheet"]') + tree.findall('style') But the problem with CSS style definitions is that the order matters, e.g. <link rel="stylesheet" type="text/css" href="/media/css/first.css" /> <style>body:{font-size: 10px;}</style> <link rel="stylesheet" type="text/css" href="/media/css/second.css" /> if the contents of the style tag is applied after the rules in the two link tags, the result may be completely different from the one where the rules are applied in order of definition. So, how would I do a lookup that inlcudes both link[@rel="stylesheet"] and style?

    Read the article

  • Understanding run time code interpretation and execution

    - by Bob
    I'm creating a game in XNA and was thinking of creating my own scripting language (extremely simple mind you). I know there's better ways to go about this (and that I'm reinventing the wheel), but I want the learning experience more than to be productive and fast. When confronted with code at run time, from what I understand, the usual approach is to parse into a machine code or byte code or something else that is actually executable and then execute that, right? But, for instance, when Chrome first came out they said their JavaScript engine was fast because it compiles the JavaScript into machine code. This implies other engines weren't compiling into machine code. I'd prefer not compiling to a lower language, so are there any known modern techniques for parsing and executing code without compiling to low level? Perhaps something like parsing the code into some sort of tree, branching through the tree, and comparing each symbol and calling some function that handles that symbol? (Wild guessing and stabbing in the dark)

    Read the article

  • Why do Java/C# edge out C++ as the recommended language to learn OOP on S.O?

    - by viksit
    I noticed after reading the answers/discussion to this question (What is the best language to learn OOP on?) - that more and more people are recommending C# or Java over C++ to learn OOP on. A simple term search on that answer page results in 10 hits for C++, 21 for C# and 27 for Java. Now, I understand that these 2 languages fix a lot of quirks and issues with C++, and looked up these resources that relate mostly to performance, JVM vs native implementation, systems focus vs applications, manual memory management vs automated et al. My question is - are there any fundamental differences in the OO capabilities of Java/C# vs C++? Or are the former recommended purely due to their generic ease of use/improvements over the latter? Thanks. PS, I'm aware of Java interface inheritance vs C++ multiple inheritance as a difference. I would consider that an implementational one rather than functional.

    Read the article

  • Creating an Extremely Large Index in Oracle

    - by Rudiger
    Can someone look at the linked reference and explain to me the precise statements to run? Oracle DBA's Guide: Creating a Large Index Here's what I came up with... CREATE TEMPORARY TABLESPACE ts_tmp TEMPFILE 'E:\temp01.dbf' SIZE 10000M REUSE AUTOEXTEND ON EXTENT MANAGEMENT LOCAL; ALTER USER me TEMPORARY TABLESPACE ts_tmp; CREATE UNIQUE INDEX big_table_idx ON big_table ( record_id ); DROP TABLESPACE ts_tmp; Edit 1 After this index was created, I ran an explain plan for a simple query and get this error: ORA-00959: tablespace 'TS_TMP' does not exist It seems like it's not temporary at all... :(

    Read the article

  • Most efficient way to save tile data of an isometric game

    - by Harmen
    Hello, I'm working on an isometric game for fast browsers that support <canvas>, which is great fun. To save information of each tile, I use a two-dimensional array which contains numbers representing a tile ID, like: var level = [[1, 1, 1, 2, 1, 0], [0, 1, 1, 2, 0, 1], [0, 1, 1, 2, 1, 1]]; var tiles = [ {name: 'grass', color: 'green'}, {name: 'water', color: 'blue'}, {name: 'forest', color: 'ForestGreen'} ]; So far it works great, but now I want to work with heights and slopes like in this picture: For each tile I need to save it's tile ID, height and information about which corners are turned upward. I came up with a simple idea about a bitwise representation of all four corners, like this: 1011 // top, bottom and left corner turned up My question is: what is the most efficient way to save these three values for each cell? Is it possible to save these three values as one integer?

    Read the article

  • C++/CLI Mixed Mode DLL Creation

    - by Adam Haile
    I've got a native C++ DLL that I would like to have a C++/CLI wrapper layer for. From what I understood, if you simple added a C++/CLI class to the project, VS would compile as mixed mode, but I was apparently wrong as VS doesn't seem to be even touching the managed code. So, given a pre-existing native code-base what exactly, step-by-step, do you need to do to create a mixed mode DLL, so that I can can link into that code from any .NET language? *I need to do this because my native code uses C++ classes that I cannot P/Invoke into.

    Read the article

  • Grails/Spring HttpServletRequest synchronization

    - by Jeff Storey
    I was writing a simple Grails app and I have a spot in a gsp where one of my java beans in modified. <g:each in="${myList}" status="i" var="myVar"> // if the user performs some view action, update one of the myVar elements </g:each> This works, but I don't think it's quite threadsafe. myList is an http request variable but in cases of pages that use ajax (or other client side manipulations), it is possible for two threads to be modifying the same request scope variable The Spring AbstractController class provides a setSynchronizeOnSession method. Does grails provide any equivalent functionality? If not, what's the best way to protect this non-threadsafe mutation? thanks, Jeff

    Read the article

  • How to download Google Cloud Messaging (GCM) from Google Code?

    - by Dennis
    I'm trying to learn how to use GCM and I want download the simple app. I'm following the instructions here: http://developer.android.com/google/gcm/server.html. Using App Engine for Java To set up the server using a standard App Engine for Java: Get the files from the open source site, as described above. I entered the link - https://code.google.com/p/gcm/ but there is no download there, and I don't have Git (and I don't know how to use it..). Can someone please explain how to download it or give me a link or something? Thank you in advance!

    Read the article

  • Creating a triple store query using SQL - how to find all triples that have a common predicate and o

    - by Ankur
    I have a database that acts like a triple store, except that it is just a simple MySQL database. I want to select all triples that have a common predicate and object. Info about RDF and triples I can't seem to work out the SQL. If I had just a single predicate and object to match I would do: select TRIPLE from TRIPLES where PREDICATE="predicateName" and OBJECT="objectName" But if I have a list (HashMap) of many pairs of (predicateName,objectName) I am not sure what I need to do. Please let me know if I need to provide more info, I am not sure that I have made this quite clear, but I am wary of providing too much info and confusing the issue.

    Read the article

  • Batch command getting error

    - by alice7
    Hi Guys, I wrote a simple batch file which checks whether the c drive path exists then execute the exe in that path else try the d drive path and execute it. IF EXIST c:\program files\x goto a ELSE goto b :a cd c:\program files\x executable.exe c:\temp\col.zip :b cd d:\program files\x executable.exe c:\temp\col.zip Im getting this error: ----Error Ouput-- 'ELSE' is not recognized as an internal or external command, operable program or batch file. The system cannot find the path specified. 'executable.exe' is not recognized as an internal or external command, operable program or batch file. 'dellsysteminfo.exe' is not recognized as an internal or external command, operable program or batch file. I don't know why.

    Read the article

  • Prepopulate drop-box according to another drop-box choice in Django Admin

    - by onorua
    I have models like this: class User(models.Model): Switch = models.ForeignKey(Switch, related_name='SwitchUsers') Port = models.ForeignKey(Port) class Switch(models.Model): Name = models.CharField(max_length=50) class Port(models.Model): PortNum = models.PositiveIntegerField() Switch = models.ForeignKey(Switch, related_name = "Ports") When I'm in Admin interface and choose Switch from Switches available, I would like to have Port prepopulated accordingly with Ports from the related Switch. As far as I understand I need to create some JS script to prepopulate it. Unfortunately I don't have this experience, and I would like to keep things simple as it possible and don't rewrite all Django admin interface. Just add this functionality for one Field. Could you please help me with my problem? Thank you.

    Read the article

  • ActiveX communication

    - by Mario Marinato -br-
    I'm developing an ActiveX EXE that exposes an specific class to a third-party software. This third-party software instanciates an object of this class and uses its methods. Strangely, this third-party software destroys its object of my exposed class as soon as it calls an specific method, but I have no idea why this happens. The only clue I have is that this method is the only one that returns a value. All the other ones are simple 'subs' that do not return any value, and when they are called nothing wrong happens. I'm using VB6. Do you guys have any idea of why it's happening?

    Read the article

  • flash - django communication -- amf, xml, or json?

    - by shanyu
    We are considering to develop a Flash front-end to a web application written using Django. The Flash front-end will send a simple "id" to the server and in response receive a couple of objects. The application will be open only to authenticated users. To the extend of my current knowledge (which is basic for Flash) we can either use AMF or take an XML or JSON approach. AMF seems to have an upperhand as there are examples out on the internet showing it can cooperate easily with Django's authentication mechanism (most examples feature pyAMF). On the other hand, implementing a XML/JSON based solution may be easier and hassle free. Guidance will be much appreciated.

    Read the article

  • How to use a CTabCtrl in a MFC dialog based application ?

    - by shan23
    I need to do something which i expected to be was simple - create a tab control which has 2 tabs, implying 2 modes of operation for my app. When user clicks on Tab1, he'll be presented with some buttons and textboxes, and when he clicks Tab2, some other input method. I noticed that there was a CTabCtrl class thats used in MFC to add tabs. However, once I added the tab ctrl using the UI designer, I couldn't specify how many tabs there'll be using property window. Searching on the net, I found some examples but all of them required you to derive from CtabCtrl , create 2 or more child dialogs etc and to write your own custom class. My question is, since I want to do something so basic, why couldn't I do it using the familiar Add Event handler/Add member variable wizard and then handle everything else inside my app's class ? Surely, the default CTabCtrl class can do something useful without needing to derive from it ?

    Read the article

  • EXC_BAD_ACCESS when not using self.

    - by chris
    I got nabbed by the following bug again and would like some clarification to exactly why it is a bug. I have a simple UITableView that loads some data: // myclass.h @property (nonatomic, retain) NSArray *myData // myclass.m @synthesize myData; - (void) viewDidLoad { ... myData = someDataSource // note the lack of self } - (UITableViewCell *) cellForRowAtIndexPath ... { ... cell.textLabel.text = [self.myData objectAtIndex:indexPath.row]; // EXC_BAD_ACCESS } The table first loads fine, but when scrolling up enough that one of the cells is totally out of the view I then get the EXC_BAD_ACCESS error. Am I missing something in regards to @property retain. My understanding is that it releases anything that the pointer was previously pointing to before the reassignment. If I am correct then why would not using self. cause any problems? Thanks for the help.

    Read the article

  • How to create a SHA1 digest on a tree of objects?

    - by Torok Balint
    Let's say that I have a tree of objects of which every one have a string representation. I want to create a SHA1 digest on the whole tree. The easiest way would be to recursively go over each node of the tree. For each node I would concatenate (as simple strings) the SHA1 digests of all the children, add the string representation of the given nod to this concatenated string, and do a SHA1 on it. This would be the SHA1 digest of the given node. The question is will this digest be just as "good" as if I would have concatenated the string representation of the child nodes, and not the digests of the child nodes? Thanks

    Read the article

  • Silly Objective-C inheritance problem when using property

    - by Ben Packard
    I've been scratching my head with this for a couple of hours - I haven't used inheritance much. Here I have set up a simple Test B class that inherits from Test A, where an ivar is declared. But I get the compilation error that the variable is undeclared. This only happens when I add the property and synthesize declarations - works fine without them. TestA Header: #import <Cocoa/Cocoa.h> @interface TestA : NSObject { NSString *testString; } @end TestA Implementation is empty: #import "TestA.h" @implementation TestA @end TestB Header: #import <Cocoa/Cocoa.h> #import "TestA.h" @interface TestB : TestA { } @property NSString *testProp; @end TestB Implementation (Error - 'testString' is undeclared) #import "TestB.h" @implementation TestB @synthesize testProp; - (void)testing{ NSLog(@"test ivar is %@", testString); } @end

    Read the article

  • How to access private static target field in aspect in AspectJ?

    - by LihO
    I have a simple class Main with private static int x and an aspect that should output the old value of x before it is reassigned: public class Main { private static int x; public static void main(String[] args) { foo(7); } public static void foo(int y) { x = y; } } and MonitorX.aj: public aspect MonitorX { before() : set(static int Main.x){ System.out.println(Main.x); } } which doesn't work since I can't access private x using Main.x. I've also tried: before(int t) : set(static int Main.x) && target(t){ System.out.println(t); } which doesn't work either (nothing is outputted, if I try to output string, it seems that the aspect isn't invoked at all). However printing out the new value that is being assigned works: before(int newVal) : set(static int Main.x) && args(newVal){ System.out.println(newVal); } What am I missing?

    Read the article

  • How to unmangle exported symbols from C++ in dynamic libraries in XCode on OSX

    - by Gerald
    I've been trying to develop a dynamic library in C++ that can be run-time loaded in an application. I finally got it working, but it's a little ugly. I have a function that takes a pointer to a C++ class as an argument, which looks like this: bool registerGrindPlugin( Grind::PluginManager* mgr ); But of course it's being exported as: _Z19registerGrindPluginPN5Grind13PluginManagerE I tried a .c file with a simple function and it exported fine as "registerGrindPlugin", but of course I can't pass a C++ class as the argument that way. Soo... my question is, is there a way to unmangle or alias the exported symbol so that I don't have to use a monstrosity like Z19registerGrindPluginPN5Grind13PluginManagerE in my dlsym call? I did see something about -alias_list as a linker option, but I haven't quite figured out how to use it in XCode. If that is the solution, can somebody provide some more details on how to use this?

    Read the article

  • Configuration file reading. Best practice

    - by Andrew Florko
    Application stores configuration data in custom section of configuration file. This information is used all over the application. Nowadays I use helper static class to to provide access like this (some code omitted or simplified): [XmlRoot("webSiteSection")] public class WebSiteConfig : IConfigurationSectionHandler { public static WebSiteConfig Current { get { if (_current == null) _current = (WebSiteConfig) ConfigurationManager.GetSection("webSiteSection"); return _current; } } [XmlElement("section1")] public Section1 Section1 { get; set; } [XmlElement("section2")] public Section2 Section2 { get; set; } ... public object Create(object parent, object configContext, XmlNode section) { var serializer = new XmlSerializer(typeof(WebSiteConfig)); return serializer.Deserialize(new XmlNodeReader(section)); } } Then I use it like this <%: WebSiteConfig.Current.Section1.Value1 %> <%: WebSiteConfig.Current.Section1.Value2 %> What do you think of it? I find it usable because it keeps code simple, but also confused as IConfigurationSectionHandler is deprecated since .NET Framework 2.0

    Read the article

  • android button setPressed after onClick

    - by strem
    yesterday I noticed the possibility to integrate Fragments in older API Levels through the Compatibility package, but thats not really essential for the question. :) I have a Button with an OnClickListener Button button = (Button) findViewById(R.id.button); button.setOnClickListener(new OnClickListener() { @Override public void onClick(View v) { doSomething(); button.setPressed(true); } }); Because of the actual clicking, it is shown as pressed and after releasing the click, the button state is not pressed and stays that way. Is there a simple way that keeps the button state pressed after releasing? First thing I can think of would be some sort of timer, but that seems unreasonable.

    Read the article

  • Tomcat: recommandations for logging

    - by WizardOfOdds
    I've read several questions here concerning Tomcat and logging but I still really don't understand the "bigger picture", hence my question: How and where are my Webapps supposed to do their logging? By default on my setup Tomcat 6.0.20 logs go in the following file/appender: ./apache-tomcat-6.0.20/logs/catalina.out Am I suppose to have my webapps also log to this file/appender? Let say my case is trivially simple and I've got just one servlet: import ... // What do I import here in order to be able to log? public class SOServlet extends HttpServlet { public void doGet( final HttpServletRequest request, final HttpServletResponse response ) throws IOException, ServletException { ... // I want to log here, what do I write? What are the gotchas knowing that there are more than one webapp running on the same Tomcat? (apparently from reading the various questions there are many gotchas). What about the .war, do I need to put log4j/sl4f/commons-logging/whatever in my .war?

    Read the article

  • The most elegant way to encapsulate WinAPI callbacks inside a class

    - by FractalizeR
    Hello. I am thinking about elegant way to encapsulate WinAPI callbacks inside a class. Suppose I am making a class handling asynchronous I/O. All Windows callbacks should be stdcall functions, not class methods (I need to pass their addresses to ReadFileEx WinAPI function for example). So, I cannot just pass method addresses as a callback routines to WinAPI functions. What is the most elegant way to encapsulate functionality of this type inside a class so that the class have events OnReadCompleted and OnWriteCompleted (I am using Delphi as a primary language, but I guess the situation must be the same in C++ because class methods are different from simple methods by the fact, that the first hidden parameter of them is this link. Of course this class is not a singleton and there can be many of them created by app at the same time. What do you think would be the good way to implement this?

    Read the article

  • How small is *too small* for an opensource project?

    - by Adam Lewis
    I have a fair number of smaller projects / libraries that I have been using over the past 2 years. I am thinking about moving them to Google Code to make it easier to share with co-workers and easier to import them into new projects on my own environments. The are things like a simple FSMs, CAN (Controller Area Network) drivers, and GPIB drivers. Most of them are small (less than 500 lines), so it makes me wonder are these types of things too small for a stand alone open-source project? Note that I would like to make it opensource because it does not give me, or my company, any real advantage.

    Read the article

< Previous Page | 800 801 802 803 804 805 806 807 808 809 810 811  | Next Page >