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• Using Matlab to find maxima for data with a lot of noise

  - by jimbo

  I have noisy data set with three peaks in Matlab and want to do some image processing on it. The peaks are about 5-9 pixels wide at the base, in a 50 x 50 array. How do I locate the peaks? Matlab is very new to me. Here is what I have so far... For my original image, let's call it "array", I tried J = fspecial('gaussian',[5 5], 1.5); C = imfilter(array, J) peaks = imregionalmax(C); but there is still some noise along the baseline between the peaks so I end up getting a ton of local max that are really just noise values. (I tried playing with the size of the filter, but that didn't help.) I also tried peaks = imextendedmax(C,threshold); where the threshold was determined visually... which works but is definitely not a good way to do it since it's not that robust obviously. So, how do I locate these peaks in a robust way? Thanks.

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• Intent provided by Cursor is not fired correctly (LiveFolders)

  - by Felix

  In my desperation with trying to get LiveFolders working, I have tried the following in my LiveFolder ContentProvider: public Cursor query(Uri uri, String[] projection, String selection, String[] selectionArgs, String sortOrder) { MatrixCursor mc = new MatrixCursor(new String[] { LiveFolders._ID, LiveFolders.NAME, LiveFolders.INTENT } ); Intent i = null; for (int j=0; j < 5; j++) { i = new Intent(Intent.ACTION_VIEW, Uri.parse("http://www.google.com/")); mc.addRow(new Object[] { j, "hello", i} ); } return mc; } Which, in all normalness, should launch the Browser and display the Google homepage when clicking on an item in the LiveFolder. But it doesn't. It gives a Application is not installed on your phone error. No, I'm not defining a base intent for my LiveFolder. logcat says: I/ActivityManager( 74): Starting activity: Intent { act=android.intent.action.VIEW dat=Intent { act=android.intent.action.VIEW dat=http://www.google.com/ } flg=0x10000000 } It seems it embeds the Intent I give it in the data section of the actually fired Intent. Why is it doing this? I'm really starting to believe it's a platform bug.

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• C# Virtual method call in constructor - how to refactor?

  - by Cristi Diaconescu

  I have an abstract class for database-agnostic cursor actions. Derived from that, there are classes that implement the abstract methods for handling database-specific stuff. The problem is, the base class ctor needs to call an abstract method - when the ctor is called, it needs to initialize the database-specific cursor. I know why this shouldn't be done, I don't need that explanation! This is my first implementation, that obviously doesn't work - it's the textbook "wrong way" of doing it. The overridden method accesses a field from the derived class, which is not yet instantiated: public abstract class CursorReader { private readonly int m_rowCount; protected CursorReader() { m_rowCount = CreateCursor(sqlCmd); //virtual call ! } protected abstract int CreateCursor(string sqlCmd); } public class SqlCursorReader : CursorReader { private SqlConnection m_sqlConnection; public SqlCursorReader(string sqlCmd, SqlConnection sqlConnection) { m_sqlConnection = sqlConnection; //field initialized here } protected override int CreateCursor(string sqlCmd) { //uses not-yet-initialized member *m_sqlConnection* //so this throws a NullReferenceException var cursor = new CustomCursor(sqlCmd, m_sqlConnection); return cursor.Count(); } } I will follow up with an answer on my attempts to fix this...

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• C to Assembly code - what does it mean

  - by Smith

  I'm trying to figure out exactly what is going on with the following assembly code. Can someone go down line by line and explain what is happening? I input what I think is happening (see comments) but need clarification. .file "testcalc.c" .section .rodata.str1.1,"aMS",@progbits,1 .LC0: .string "x=%d, y=%d, z=%d, result=%d\n" .text .globl main .type main, @function main: leal 4(%esp), %ecx // establish stack frame andl $-16, %esp // decrement %esp by 16, align stack pushl -4(%ecx) // push original stack pointer pushl %ebp // save base pointer movl %esp, %ebp // establish stack frame pushl %ecx // save to ecx subl $36, %esp // alloc 36 bytes for local vars movl $11, 8(%esp) // store 11 in z movl $6, 4(%esp) // store 6 in y movl $2, (%esp) // store 2 in x call calc // function call to calc movl %eax, 20(%esp) // %esp + 20 into %eax movl $11, 16(%esp) // WHAT movl $6, 12(%esp) // WHAT movl $2, 8(%esp) // WHAT movl $.LC0, 4(%esp) // WHAT?!?! movl $1, (%esp) // move result into address of %esp call __printf_chk // call printf function addl $36, %esp // WHAT? popl %ecx popl %ebp leal -4(%ecx), %esp ret .size main, .-main .ident "GCC: (Ubuntu 4.3.3-5ubuntu4) 4.3.3" .section .note.GNU-stack,"",@progbits Original code: #include <stdio.h> int calc(int x, int y, int z); int main() { int x = 2; int y = 6; int z = 11; int result; result = calc(x,y,z); printf("x=%d, y=%d, z=%d, result=%d\n",x,y,z,result); }

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• Indices instead of pointers in STL containers?

  - by zvrba

  Due to specific requirements [*], I need a singly-linked list implementation that uses integer indices instead of pointers to link nodes. The indices are always interpreted with respect to a vector containing the list nodes. I thought I might achieve this by defining my own allocator, but looking into the gcc's implementation of , they explicitly use pointers for the link fields in the list nodes (i.e., they do not use the pointer type provided by the allocator): struct _List_node_base { _List_node_base* _M_next; ///< Self-explanatory _List_node_base* _M_prev; ///< Self-explanatory ... } (For this purpose, the allocator interface is also deficient in that it does not define a dereference function; "dereferencing" an integer index always needs a pointer to the underlying storage.) Do you know a library of STL-like data structures (i am mostly in need of singly- and doubly-linked list) that use indices (wrt. a base vector) instead of pointers to link nodes? [*] Saving space: the lists will contain many 32-bit integers. With two pointers per node (STL list is doubly-linked), the overhead is 200%, or 400% on 64-bit platform, not counting the overhead of the default allocator.

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• Is this a good decorator pattern for javascript?

  - by Kucebe

  I need some simple objects that could become more complex later, with many different properties, so i thought to decorator pattern. I made this looking at Crockford's power constructor and object augmentation: //add property to object Object.prototype.addProperty = function(name, func){ for(propertyName in this){ if(propertyName == name){ throw new Error(propertyName + " is already defined"); } } this[name] = func; }; //constructor of base object var BaseConstructor = function(param){ var _privateVar = param; return{ getPrivateVar: function(){ return _privateVar; } }; }; //a simple decorator, adds one private attribute and one privileged method var simpleDecorator = function(obj, param){ var _privateVar = param; var privilegedMethod1 = function(){ return "privateVar of decorator is: " + _privateVar; }; obj.addProperty("privilegedMethod1", privilegedMethod1); return obj; } //a more complex decorator, adds public and private properties var complexDecorator = function(obj, param1, param2){ //private properties var _privateVar = param1; var _privateMethod = function(x){ for(var i=0; i<x; i++){ _privateVar += x; } return _privateVar; }; //public properties var publicVar = "I'm public"; obj.addProperty("publicVar", publicVar); var privilegedMethod2 = function(){ return _privateMethod(param2); }; obj.addProperty("privilegedMethod2", privilegedMethod2); var publicMethod = function(){ var temp = this.privilegedMethod2(); return "do something: " + temp + " - publicVar is: " + this.publicVar; }; obj.addProperty("publicMethod", publicMethod); return obj; } //new basic object var myObj = BaseConstructor("obj1"); //the basic object will be decorated var myObj = simpleDecorator(obj, "aParam"); //the basic object will be decorated with other properties var myObj = complexDecorator(obj, 2, 3); Is this a good way to have Decorator Pattern in javascript? Are there other better ways to do this?

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• prevent schemagen from adding the super-class to the schema?

  - by shay

  Hi, how do i prevent schemagen from adding the super-class to the schema? I have tried using XMLTransient on the super-class, and on its fields but they still show up in the schema . for example : @XmlTransient public class Asset { @XmlTransient public Long ID; } public class Movie extends Asset { } creates this schema : <xs:complexType name="asset"> <xs:sequence> <xs:element name="ID" type="xs:long" minOccurs="0"/> </xs:sequence> </xs:complexType> <xs:complexType name="movie"> <xs:complexContent> <xs:extension base="asset"> <xs:sequence/> </xs:extension> </xs:complexContent> </xs:complexType> the schema that i would like to see is : <xs:complexType name="movie"> <xs:complexContent> <xs:sequence/> </xs:extension> </xs:complexContent> </xs:complexType>

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• Creating a Linq->HQL provider

  - by Mike Q

  Hi all, I have a client application that connects to a server. The server uses hibernate for persistence and querying so it has a set of annotated hibernate objects for persistence. The client sends HQL queries to the server and gets responses back. The client has an auto-generated set of objects that match the server hibernate objects for query results and basic persistence. I would like to support using Linq to query as well as Hql as it makes the queries typesafe and quicker to build (no more typos in HQL string queries). I've looked around at the following but I can't see how to get them to fit with what I have. NHibernate's Linq provider - requires using NHibernate ISession and ISessionFactory, which I don't have LinqExtender - requires a lot of annotations on the objects and extending a base type, too invasive What I really want is something that will generate give me a nice easy to process structure to build the HQL queries from. I've read most of a 15 page article written by one of the C# developers on how to create custom providers and it's pretty fraught, mainly because of the complexity of the expression tree. Can anyone suggest an approach for implementing Linq - HQL translation? Perhaps a library that will the cleanup of the expression tree into something more SQL/HQLish. I would like to support select/from/where/group by/order by/joins. Not too worried about subqueries.

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• how to elegantly duplicate a graph (neural network)

  - by macias

  I have a graph (network) which consists of layers, which contains nodes (neurons). I would like to write a procedure to duplicate entire graph in most elegant way possible -- i.e. with minimal or no overhead added to the structure of the node or layer. Or yet in other words -- the procedure could be complex, but the complexity should not "leak" to structures. They should be no complex just because they are copyable. I wrote the code in C#, so far it looks like this: neuron has additional field -- copy_of which is pointer the the neuron which base copied from, this is my additional overhead neuron has parameterless method Clone() neuron has method Reconnect() -- which exchanges connection from "source" neuron (parameter) to "target" neuron (parameter) layer has parameterless method Clone() -- it simply call Clone() for all neurons network has parameterless method Clone() -- it calls Clone() for every layer and then it iterates over all neurons and creates mappings neuron=copy_of and then calls Reconnect to exchange all the "wiring" I hope my approach is clear. The question is -- is there more elegant method, I particularly don't like keeping extra pointer in neuron class just in case of being copied! I would like to gather the data in one point (network's Clone) and then dispose it completely (Clone method cannot have an argument though).

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• C++ How to read a string of text and create object of their class

  - by user1777711

  After reading a text file... The following information is available Point2D, [3, 2] Line3D, [7, 12, 3], [-9, 13, 68] Point3D, [1, 3, 8] Line2D, [5, 7], [3, 8] Point2D, [3, 2] Line3D, [7, -12, 3], [9, 13, 68] Point3D, [6, 9, 5] Point2D, [3, 2] Line3D, [70, -120, -3], [-29, 1, 268] Line3D, [25, -69, -33], [-2, -41, 58] Point3D, [6, 9, -50] The first data separate by the delimiter comma is the class name. for each of the 4 class Point2D,Line3D,Point3D,Line2D How do i like store them into relevant object base on their class means.. when it read first line Point2D, [3, 2] It will store it as Point2D object with the Data [3, 2] But the issue is what dataset should i pick, Vector, Set , Map or List I was thinking to actually create a data set then but i can't use new Point2D(); since Point2D is parent of Point3D Line2D is parent of Line3D and theres no parent class of Point2D and Line2D. how can i like create a object of them in a data set like e.g Vector so Vector[0] is of Point2D class with data [3,2] , then Vector[1] is of Line3D class with data [7, 12, 3], [-9, 13, 68] Thanks for helping.!

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• Why is Routes.rb not loading the IPs from cache?

  - by Christian Fazzini

  I am testing this in local. My ip is 127.0.0.1. The ip_permissions table, is empty. When I browse the site, everything works as expected. Now, I want to simulate browsing the site with a banned IP. So I add the IP into the ip_permissions table via: IpPermission.create!(:ip => '127.0.0.1', :note => 'foobar', :category => 'blacklist') In Rails console, I clear the cache via; Rails.cache.clear. I browse the site. I don't get sent to pages#blacklist. If I restart the server. And browse the site, then I get sent to pages#blacklist. Why do I need to restart the server every time the ip_permissions table is updated? Shouldn't it fetch it based on cache? Routes look like: class BlacklistConstraint def initialize @blacklist = IpPermission.blacklist end def matches?(request) @blacklist.map { |b| b.ip }.include? request.remote_ip end end Foobar::Application.routes.draw do match '/(*path)' => 'pages#blacklist', :constraints => BlacklistConstraint.new .... end My model looks like: class IpPermission < ActiveRecord::Base validates_presence_of :ip, :note, :category validates_uniqueness_of :ip, :scope => [:category] validates :category, :inclusion => { :in => ['whitelist', 'blacklist'] } def self.whitelist Rails.cache.fetch('whitelist', :expires_in => 1.month) { self.where(:category => 'whitelist').all } end def self.blacklist Rails.cache.fetch('blacklist', :expires_in => 1.month) { self.where(:category => 'blacklist').all } end end

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• django test client trouble

  - by Anton Koval'

  I've got a problem... we're writing project using django, and i'm trying to use django.test.client with nose test-framework for tests. Our code is like this: from simplejson import loads from urlparse import urljoin from django.test.client import Client TEST_URL = "http://smakly.localhost:9090/" def test_register(): cln = Client() ref_data = {"email": "[email protected]", "name": "???????", "website": "http://hot.bear.com", "xhr": "true"} print urljoin(TEST_URL, "/accounts/register/") response = loads(cln.post(urljoin(TEST_URL, "/accounts/register/"), ref_data)) print response["message"] and in nose output I catch: Traceback (most recent call last): File "/home/psih/work/svn/smakly/eggs/nose-0.11.1-py2.6.egg/nose/case.py", line 183, in runTest self.test(*self.arg) File "/home/psih/work/svn/smakly/src/smakly.tests/smakly/tests/frontend/test_profile.py", line 25, in test_register response = loads(cln.post(urljoin(TEST_URL, "/accounts/register/"), ref_data)) File "/home/psih/work/svn/smakly/parts/django/django/test/client.py", line 313, in post response = self.request(**r) File "/home/psih/work/svn/smakly/parts/django/django/test/client.py", line 225, in request response = self.handler(environ) File "/home/psih/work/svn/smakly/parts/django/django/test/client.py", line 69, in __call__ response = self.get_response(request) File "/home/psih/work/svn/smakly/parts/django/django/core/handlers/base.py", line 78, in get_response urlconf = getattr(request, "urlconf", settings.ROOT_URLCONF) File "/home/psih/work/svn/smakly/parts/django/django/utils/functional.py", line 273, in __getattr__ return getattr(self._wrapped, name) AttributeError: 'Settings' object has no attribute 'ROOT_URLCONF' My settings.py file does have this attribute. If I get the data from the server with standard urllib2.urllopen().read() it works in the proper way. Any ideas how I can solve this case?

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• How would I go about sharing variables in a C++ class with Lua?

  - by Nicholas Flynt

  I'm fairly new to Lua, I've been working on trying to implement Lua scripting for logic in a Game Engine I'm putting together. I've had no trouble so far getting Lua up and running through the engine, and I'm able to call Lua functions from C and C functions from Lua. The way the engine works now, each Object class contains a set of variables that the engine can quickly iterate over to draw or process for physics. While game objects all need to access and manipulate these variables in order for the Game Engine itself to see any changes, they are free to create their own variables, a Lua is exceedingly flexible about this so I don't forsee any issues. Anyway, currently the Game Engine side of things are sitting in C land, and I really want them to stay there for performance reasons. So in an ideal world, when spawning a new game object, I'd need to be able to give Lua read/write access to this standard set of variables as part of the Lua object's base class, which its game logic could then proceed to run wild with. So far, I'm keeping two separate tables of objects in place-- Lua spawns a new game object which adds itself to a numerically indexed global table of objects, and then proceeds to call a C++ function, which creates a new GameObject class and registers the Lua index (an int) with the class. So far so good, C++ functions can now see the Lua object and easily perform operations or call functions in Lua land using dostring. What I need to do now is take the C++ variables, part of the GameObject class, and expose them to Lua, and this is where google is failing me. I've encountered a very nice method here which details the process using tags, but I've read that this method is deprecated in favor of metatables. What is the ideal way to accomplish this? Is it worth the hassle of learning how to pass class definitions around using libBind or some equivalent method, or is there a simple way I can just register each variable (once, at spawn time) with the global lua object? What's the "current" best way to do this, as of Lua 5.1.4?

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• Have you considered doing revenue sharing to fund development of a mobile app? How would you do it?

  - by Brennan

  I am looking to build multiple mobile apps which leverage existing content and resources by enabling these mobile apps with web services. I will duplication much of the same features which are also in place and add more features that are possible on a mobile device like address book, maps and calendar integration to make the service much more useful. To fund these projects I see that I have 2 options. First I could simply quote them for the project based on my hourly rate and the estimate in hours that I will take the to complete the job. That may be a high number. The second option would be to do shared revenue with ads placed in the app. I could then take a percentage of any revenue that is generated from the app. There is also a hybrid where I might charge for a percentage of the estimated quote and then take a percentage of the revenue sharing. So my question is how much should I propose for the revenue sharing? Should it be 30%? Or maybe I should make it 70% up to a point that a certain dollar amount is reached? And should the revenue sharing agreement be for 12 months, 24 months or more? Should I include in the proposal an agreement that they will help promote this app with their content and resources? Ultimately this system will benefit both sides because it extends their reach into the mobile space instead of where they are currently with just print and web. I have tried to find some examples with a few Google searches but I keep hitting content about the Google and Apple revenue sharing models. I would like to get some solid examples that are working to compare against so that my proposal do build these apps is not completely off base.

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• How can I embed images within my application and use them in HTML control?

  - by Atara

  Is there any way I can embed the images within my exe (as resource?) and use it in generated HTML ? Here are the requirements: A. I want to show dynamic HTML content (e.g. using webBrowser control, VS 2008, VB .Net, winForm desktop application) B. I want to generate the HTML on-the-fly using XML and XSL (file1.xml or file2.xml transformed by my.xsl) C. The HTML may contain IMG tags (file1.gif and or file2.gif according to the xml+xsl transformation) and here comes the complicated one: D. All these files (file1.xml, file2.xml, my.xsl, file1.gif, file2.gif) should be embedded in one exe file. I guess the XML and XSL can be embedded resources, and I can read them as stream, but what ways do I have to reference the image within the HTML ? <IMG src="???" /> I do not want to use absolute path and external files. If the image files are resources, can I use relative path? Relative to what? (I can use BASE tag, and then what?) Can I use stream as in email messages? If so, where can I find the format I need to use? http://www.websiteoptimization.com/speed/tweak/inline-images/ are browser dependent. What is the browser used by webBrowser control? IE? what version? Does it matter if I use GIF or JPG or BMP (or any other image format) for the images? Does it matter if I use mshtml library and not the regular webBrowser control? (currently I use http://www.itwriting.com/htmleditor/index.php ) Does it matter if I upgrade to VS 2010 ? Thanks, Atara

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• Nullability (Regular Expressions)

  - by danportin

  In Brzozowski's "Derivatives of Regular Expressions" and elsewhere, the function d(R) returning ? if a R is nullable, and Ø otherwise, includes clauses such as the following: d(R1 + R2) = d(R1) + d(R2) d(R1 · R2) = d(R1) ? d(R2) Clearly, if both R1 and R2 are nullable then (R1 · R2) is nullable, and if either R1 or R2 is nullable then (R1 + R2) is nullable. It is unclear to me what the above clauses are supposed to mean, however. My first thought, mapping (+), (·), or the Boolean operations to regular sets is nonsensical, since in the base case, d(a) = Ø (for all a ? S) d(?) = ? d(Ø) = Ø and ? is not a set (nor is the return type of d, which is a regular expression). Furthermore, this mapping isn't indicated, and there is a separate notation for it. I understand nullability, but I'm lost on the definition of the sum, product, and Boolean operations in the definition of d: how are ? or Ø returned from d(R1) ? d(R2), for instance, in the definition off d(R1 · R2)?

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• Java Package - To create a button and import one when needed.

  - by Zopyrus

  This is more like a package/import test. We'll start with my base folder at .../javaf/test.java My goal is to create subcategory and create a class with a button that I can import to test.java when I need a button. I feel like I've done it right, I know that the button doesn't do anything as of now, but I just want to make the whole thing work and expand the code thereafter. So here goes - This is test.java import paket.*; // importing classes from subcategory paket! import javax.swing.*; import java.awt.*; import java.awt.event.*; import java.util.*; public class test { public test() { JFrame myFrame; JPanel myPanel; myFrame = new JFrame("Hello FramWorld"); myPanel = new JPanel(); // Here I want to add the object created in paket/myButts.java // The problem is how to make these two lines work. myButts myButton = new myButts(); myPanel.add(myButton); myFrame.setVisible(true); myFrame.getContentPane().add(myPanel, BorderLayout.CENTER); myFrame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); myFrame.pack(); } public static void main(String args[]) { new test(); } } And here is my .../javaf/paket/myButts.java package paket; // Here is the package function (ought to work like a link) import javax.swing.*; import java.awt.*; import java.awt.event.*; // This class should only create a button. public class myButts { public myButts() { JButton myButt = new JButton(); } } I've compiled myButts.java with no errors. But then I compile test.java and it gives me the following error: test.java:19: cannot find symbol symbol : method add(paket.myButts) location: class javax.swing.JPanel myPanel.add(myButton); Thanks for reading, Z

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• Why does GetWindowThreadProcessId return 0 when called from a service

  - by Marve

  When using the following class in a console application, and having at least one instance of Notepad running, GetWindowThreadProcessId correctly returns a non-zero thread id. However, if the same code is included in a Windows Service, GetWindowThreadProcessId always returns 0 and no exceptions are thrown. Changing the user the service launches under to be the same as the one running the console application didn't alter the result. What causes GetWindowThreadProcessId to return 0 even if it is provided with a valid hwnd? And why does it function differently in the console application and the service? Note: I am running Windows 7 32-bit and targeting .NET 3.5. public class TestClass { [DllImport("user32.dll")] static extern uint GetWindowThreadProcessId(IntPtr hWnd, IntPtr ProcessId); public void AttachToNotepad() { var processesToAttachTo = Process.GetProcessesByName("Notepad") foreach (var process in processesToAttachTo) { var threadID = GetWindowThreadProcessId(process.MainWindowHandle, IntPtr.Zero); .... } } } Console Code: class Program { static void Main(string[] args) { var testClass = new TestClass(); testClass.AttachToNotepad(); } } Service Code: public class TestService : ServiceBase { private TestClass testClass = new TestClass(); static void Main() { ServiceBase.Run(new TestService()); } protected override void OnStart(string[] args) { testClass.AttachToNotepad(); base.OnStart(args); } protected override void OnStop() { ... } }

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• Facebook Connect Login redirecting in Chrome and Safari

  - by Lobe

  I am having a problem with Facebook Connect that I can't seem to get my head around. A user clicks on the fb-login button, the pop up appears and they authenticate, the pop up closes and the on-login function is called. This happens in IE and Firefox as is expected. However in Chrome and Safari, the pop up redirects to the canvas url and doesn't close. Also the on-login function isn't called. I have googled and it seems to be something to do with the xd-receiver.htm file, however it seems weird that it is working in IE and Firefox but not Chrome or Safari. Thanks The facebook javascript <script src="http://static.ak.connect.facebook.com/js/api_lib/v0.4/FeatureLoader.js.php/en_US" type="text/javascript"></script> <script type="text/javascript">FB.init("xxxxxxxxxxxxxxxxxx","xd_receiver.htm");</script> And the button <fb:login-button v="2" size="large" onlogin='window.location = "http://www.xxxxxxxxxx.com/development/redirect.php?size=large";'>Connect</fb:login-button> Obviously with Appid and domain hidden. Any ideas? EDIT: After a bit more playing around it turned out that I didn't have my base domain set in Facebook settings. Why it works in some browsers and not others beats me, however it works now. Thanks NSD for your suggestion.

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• How to enforce users to create objects of class derived from mine with "new" only?

  - by sharptooth

  To implement reference counting we use an IUnknown-like interface and a smart pointer template class. The interface has implementation for all the reference-count methods, including Release(): void IUnknownLike::Release() { if( --refCount == 0 ) { delete this; } } The smart pointer template class has a copy constructor and an assignment operator both accepting raw pointers. So users can do the following: class Class : public IUnknownLike { }; void someFunction( CSmartPointer<Class> object ); //whatever function Class object; someFunction( &object ); and the program runs into undefined behavior - the object is created with reference count zero, the smart pointer is constructed and bumps it to one, then the function returns, smart pointer is destroyed, calls Release() which leads to delete of a stack-allocated variable. Users can as well do the following: struct COuter { //whatever else; Class inner;// IUnknownLike descendant }; COuter object; somefunction( &object.Inner ); and again an object not created with new is deleted. Undefined behavior at its best. Is there any way to change the IUnknownLike interface so that the user is forced to use new for creating all objects derived from IUnknownLike - both directly derived and indirectly derived (with classes in between the most derived and the base)?

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• detect shutdown in window service

  - by deepu

  hi, i have a windows service that get user details and save the result into log text file. and, my problem is when i shut down or log off my system, i also would like to save the time that i down my system into that log file. but, i don't know how to do that. I checked the winproc method to detect shutdown operation but i was not able to use it on window service, on googling found it can be used with forms only. how can we detect user have clicked shutdown or log off and do some action. so,please give me some idea or suggestion on that. i have used it for logoff but on log entry is made when i logoff the system protected override void OnSessionChange(SessionChangeDescription changeDescription) { this.RequestAdditionalTime(250000); //gives a 25 second delay on Logoff if (changeDescription.Reason == SessionChangeReason.SessionLogoff) { // Add your save code here StreamWriter str = new StreamWriter("D:\\Log.txt", true); str.WriteLine("Service stoped due to " + changeDescription.Reason.ToString() + "on" + DateTime.Now.ToString()); str.Close(); } base.OnSessionChange(changeDescription); }

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• How to patch an S4 method in an R package?

  - by Richie Cotton

  If you find a bug in a package, it's usually possible to patch the problem with fixInNamespace, e.g. fixInNamespace("mean.default", "base"). For S4 methods, I'm not sure how to do it though. The method I'm looking at is in the gWidgetstcltk package. You can see the source code with getMethod(".svalue", c("gTabletcltk", "guiWidgetsToolkittcltk")) I can't find the methods with fixInNamespace. fixInNamespace(".svalue", "gWidgetstcltk") Error in get(subx, envir = ns, inherits = FALSE) : object '.svalue' not found I thought setMethod might do the trick, but setMethod(".svalue", c("gTabletcltk", "guiWidgetsToolkittcltk"), definition = function (obj, toolkit, index = NULL, drop = NULL, ...) { widget = getWidget(obj) sel <- unlist(strsplit(tclvalue(tcl(widget, "selection")), " ")) if (length(sel) == 0) { return(NA) } theChildren <- .allChildren(widget) indices <- sapply(sel, function(i) match(i, theChildren)) inds <- which(visible(obj))[indices] if (!is.null(index) && index == TRUE) { return(inds) } if (missing(drop) || is.null(drop)) drop = TRUE chosencol <- tag(obj, "chosencol") if (drop) return(obj[inds, chosencol, drop = drop]) else return(obj[inds, ]) }, where = "package:gWidgetstcltk" ) Error in setMethod(".svalue", c("gTabletcltk", "guiWidgetsToolkittcltk"), : the environment "gWidgetstcltk" is locked; cannot assign methods for function ".svalue" Any ideas?

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• How can I refactor this to work without breaking the pattern horribly?

  - by SnOrfus

  I've got a base class object that is used for filtering. It's a template method object that looks something like this. public class Filter { public void Process(User u, GeoRegion r, int countNeeded) { List<account> selected = this.Select(u, r, countNeeded); // 1 List<account> filtered = this.Filter(selected, u, r, countNeeded); // 2 if (filtered.Count > 0) { /* do businessy stuff */ } // 3 if (filtered.Count < countNeeded) this.SendToSuccessor(u, r, countNeeded - filtered) // 4 } } Select(...), Filter(...) are protected abstract methods and implemented by the derived classes. Select(...) finds objects in the based on x criteria, Filter(...) filters those selected further. If the remaining filtered collection has more than 1 object in it, we do some business stuff with it (unimportant to the problem here). SendToSuccessor(...) is called if there weren't enough objects found after filtering (it's a composite where the next class in succession will also be derived from Filter but have different filtering criteria) All has been ok, but now I'm building another set of filters, which I was going to subclass from this. The filters I'm building however would require different params and I don't want to just implement those methods and not use the params or just add to the param list the ones I need and have them not used in the existing filters. They still perform the same logical process though. I also don't want to complicated the consumer code for this (which looks like this) Filter f = new Filter1(); Filter f2 = new Filter2(); Filter f3 = new Filter3(); f.Sucessor = f2; f2.Sucessor = f3; /* and so on adding filters as successors to previous ones */ foreach (User u in users) { foreach (GeoRegion r in regions) { f.Process(u, r, ##); } } How should I go about it?

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• Dynamic Auto updating (to UI, Grid) binding list in C# Winform?

  - by Dhana

  I'm not even sure if i'm doing this correctly. But basically I have a list of objects that are built out of a class/interface. From there, I am binding the list to a datagrid view that is on a Windows Form (C#) Here the list is a Sync list which will auto update the UI, in this case datagridview. Every thing works fine now, but now i would like to have the List should have an dynamic object, that is the object will have by default two static property (ID, Name), and at run time user will select remaining properties. These should be bind to the data grid. Any update on the list should be auto reflected in the grid. I am aware that, we can use dynamic objects, but i would like to know , how to approach for solution, datagridview.DataSource = myData; // myData is AutoUpdateList<IPersonInfo> Now IPersonInfo is the type of object, need to add dynamic properties for this type at runtime. public class AutoUpdateList<T> : System.ComponentModel.BindingList<T> { private System.ComponentModel.ISynchronizeInvoke _SyncObject; private System.Action<System.ComponentModel.ListChangedEventArgs> _FireEventAction; public AutoUpdateList() : this(null) { } public AutoUpdateList(System.ComponentModel.ISynchronizeInvoke syncObject) { _SyncObject = syncObject; _FireEventAction = FireEvent; } protected override void OnListChanged(System.ComponentModel.ListChangedEventArgs args) { try { if (_SyncObject == null) { FireEvent(args); } else { _SyncObject.Invoke(_FireEventAction, new object[] { args }); } } catch (Exception) { // TODO: Log Here } } private void FireEvent(System.ComponentModel.ListChangedEventArgs args) { base.OnListChanged(args); } } Could you help out on this?

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• Having trouble hiding keyboard using invisible button which sits on top of uiscrollview

  - by phil

  I have 3 items in play... 1) UIView sits at the base of the hierarchy and contains the UIScrollview. 2) UIScrollview that is presenting a lengthy user form. 3) An invisible button on the UIScrollview that I'm using to provide "hide the keyboard" features. Notice in the code below that I'm registering to be notified when the keyboard is going to appear and again when it's going to disappear. These are working great. My problem is seemingly one of "layers". See below where I insert the button into the view atIndex:0. This causes the button to be activated and "stuffed" behind the scrollview so that when you click on it, the scrollview grabs the touch and the button is unaware. There is no way to "reach" the button and suppress the keyboard. However, if I insert atIndex:1, the button gets super imposed on top of the text entry fields and so any touch at all is acted upon by the button, which immediately suppresses the keyboard and then disappears. How do I insert the button on top of the UIScrollview but behind the UITextfields that sit there? other logistics: I have a -(void) hidekeyboard function that I have setup with the UIButtion as an IBAction(). And I have the UIButton connected to "files owner" via a ctrl-drag/drop. (Do I need both of those conventions?) This code in ViewDidLoad()... [[NSNotificationCenter defaultCenter] addObserverForName:UIKeyboardWillShowNotification object:nil queue:nil usingBlock:^(NSNotification *notification){ [self.view insertSubview:self.keyboardDismissalButton atIndex:0]; }];

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