virtual lab - Page 409 - Developer IT

Recommended ASP.NET Shared Hosting (USA)

- by coffeeaddict

Ok, I have to admit I'm getting fed up with www.discountasp.net's pricing model and this annoyance has built up over the past 8 years or so. I've been with them for years and absolutely love them on the technical side, however it's getting ridiculously expensive for so little that you get. I mean here's my scenario: 1) I am running 2 SQL Server databases which costs me $10/ea per month so that's $20/month for 2 and I only get 500 mb disk space which is horrible 2) I am paying $10/mo just for the hosting itself which I only get 1 gig of disk space! I mean common! 3) I am simply running 2 small apps (Screwturn Wiki & Subtext Blog)...so I don't really care if it's up 99% or not, it's not worth paying a total of $300 just to keep these 2 apps running over discountasp.net Anyone else feel the same? Yes, I know they have great support, probably have great servers running behind this but in the end I really don't care as long as my site is up 95% or better. Yes, the hosting toolset rocks. But you know I bet you I can find a similar set somewhere else. I like how I can totally control IIS 7 at discountasp and I can control my own app pool etc. That's very powerful and essential. But anyone have any good alternatives to discountasp that gives me close to the same at a much more reasonable cost point? I mean http://www.m6.net/prices.aspx gives you 10 SQL Databases for $7 and 200 gigs disk space! I don't know about their tools or support but just looking at those numbers and some other hosts I've seen, I feel that discountasp.net is way out of line. They don't even offer any purchasing discounts such as it would be nice if my 2nd SQL Server is only $5/month not $10...stuff like this, to make it much more realistic and fair. Opinions (people who do have discountasp.net, people who have left them, or people who have another host they like)??? But geez $300 just to host a couple DBs and lightweight open source apps? Not worth the price they are charging. I'm almost at a price point that enables me to get a decent dedicated server! I really don't care about beta ASP.NET frameworks support. Not a big deal to me. If you have alternative suggestions rather than your experience with discountasp, I'd like to know how their toolset is. Do you have complete control over your DB in terms of adding users, and same goes for the web app pool, etc.? Discountasp.net's control panel rocks. I don't want to loose the ability to at least control and add virtual directories, recycle my dedicated app pool myself, backup my sql database myself, through tools which is what discountasp does give you. I'd also want to know that the hoster at least gets the latest and greatest in terms of non-beta ASP.NET related frameworks available to its shared hosters.

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SSL and mod_rewrite error

- by wnoveno

Hi, I have https on my site. Pages with rewritten URL in my site are inaccessible while direct urls (folders). here's the htaccess ## 2009-12-17 16:52 JGC [START] ## Enable http compression for this site <IfModule mod_deflate.c> SetOutputFilter DEFLATE ## Directive "DeflateCompressionLevel" not allowed in .htaccess, only valid in server config and virtual hosts # DeflateCompressionLevel 9 # file-types indicated will not be compressed SetEnvIfNoCase Request_URI \.(?:gif|jpe?g|png)$ no-gzip dont-vary SetEnvIfNoCase Request_URI \.(?:swf|flv|pdf)$ no-gzip dont-vary SetEnvIfNoCase Request_URI \.(?:exe|t?gz|zip|gz2|sit|rar)$ no-gzip dont-vary <IfModule mod_headers.c> Header append Vary User-Agent </IfModule> </IfModule> ## 2009-12-17 16:52 JGC [END] ## 2010-03-05 16:05 JGC [START] #<IfModule mod_alias.c> #RedirectMatch 301 ^(/)$ /online-casino-poker-register.html #RedirectMatch 301 ^(/en)$ /en/online-casino-poker-register.html #RedirectMatch 301 ^(/en/)$ /en/online-casino-poker-register.html #RedirectMatch 301 ^(/en\.html)$ /en/online-casino-poker-register.html #RedirectMatch 301 ^(/sc)$ /sc/online-casino-poker-register.html #RedirectMatch 301 ^(/sc/)$ /sc/online-casino-poker-register.html #RedirectMatch 301 ^(/sc\.html)$ /sc/online-casino-poker-register.html #RedirectMatch 301 ^(/ch)$ /ch/online-casino-poker-register.html #RedirectMatch 301 ^(/ch/)$ /ch/online-casino-poker-register.html #RedirectMatch 301 ^(/ch\.html)$ /ch/online-casino-poker-register.html #</IfModule> ## 2010-03-05 16:05 JGC [END] ## # @version $Id: htaccess.txt 10492 2008-07-02 06:38:28Z ircmaxell $ # @package Joomla # @copyright Copyright (C) 2005 - 2008 Open Source Matters. All rights reserved. # @license http://www.gnu.org/copyleft/gpl.html GNU/GPL # Joomla! is Free Software ## ##################################################### # READ THIS COMPLETELY IF YOU CHOOSE TO USE THIS FILE # # The line just below this section: 'Options +FollowSymLinks' may cause problems # with some server configurations. It is required for use of mod_rewrite, but may already # be set by your server administrator in a way that dissallows changing it in # your .htaccess file. If using it causes your server to error out, comment it out (add # to # beginning of line), reload your site in your browser and test your sef url's. If they work, # it has been set by your server administrator and you do not need it set here. # ##################################################### ## Can be commented out if causes errors, see notes above. Options +FollowSymLinks # # mod_rewrite in use RewriteEngine On #RewriteLog "/var/www/html/dafa888/rewrite.log" #RewriteLogLevel 3 RewriteCond %{HTTP_COOKIE} !jfcookie\[lang\] [NC] RewriteCond %{HTTP:Accept-Language} ^zh-cn [NC] RewriteRule ^$ /sc/ [L,R=301] RewriteCond %{HTTP_COOKIE} !jfcookie\[lang\] [NC] RewriteCond %{HTTP:Accept-Language} ^zh-tw [NC] RewriteRule ^$ /ch/ [L,R=301] #RewriteCond %{HTTP_COOKIE} !jfcookie[lang] [NC] #RewriteCond %{HTTP_COOKIE} jfcookie\[lang\] [NC] #RewriteCond %{HTTP_COOKIE} jfcookie\[lang\]=([^;]+) [NC] #RewriteRule ^(.*)$ /%1/$1 [NC,QSA] ########## Begin - Rewrite rules to block out some common exploits ## If you experience problems on your site block out the operations listed below ## This attempts to block the most common type of exploit `attempts` to Joomla! # # Block out any script trying to set a mosConfig value through the URL RewriteCond %{QUERY_STRING} mosConfig_[a-zA-Z_]{1,21}(=|\%3D) [OR] # Block out any script trying to base64_encode crap to send via URL RewriteCond %{QUERY_STRING} base64_encode.*$.*$ [OR] # Block out any script that includes a <script> tag in URL RewriteCond %{QUERY_STRING} (\<|%3C).*script.*(\>|%3E) [NC,OR] # Block out any script trying to set a PHP GLOBALS variable via URL RewriteCond %{QUERY_STRING} GLOBALS(=|\[|\%[0-9A-Z]{0,2}) [OR] # Block out any script trying to modify a _REQUEST variable via URL RewriteCond %{QUERY_STRING} _REQUEST(=|\[|\%[0-9A-Z]{0,2}) # Send all blocked request to homepage with 403 Forbidden error! RewriteRule ^(.*)$ index.php [F,L] # ########## End - Rewrite rules to block out some common exploits # Uncomment following line if your webserver's URL # is not directly related to physical file paths. # Update Your Joomla! Directory (just / for root) RewriteBase / #RewriteCond %{HTTP_HOST} ^(.*)$ [NC] #RewriteRule ^(.*)$ http://www.%1/$1 [R=301] ########## Begin - Joomla! core SEF Section # RewriteCond %{REQUEST_FILENAME} !-f RewriteCond %{REQUEST_FILENAME} !-d RewriteCond %{REQUEST_URI} !^/index.php RewriteCond %{REQUEST_URI} (/|\.php|\.html|\.htm|\.feed|\.pdf|\.raw|/[^.]*)$ [NC] RewriteRule (.*) index.php RewriteRule .* - [E=HTTP_AUTHORIZATION:%{HTTP:Authorization},L] # ########## End - Joomla! core SEF Section

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Unable to host WCF service correctly in IIS7

- by user206736

I have a WCF Service library written in .NET 4.0. I have a WCF application (in order to host this service in IIS) within the same solution. It contains the WCF library assembly reference and a service.svc file pointing to the service from the library along with a web.config that is a replica of the WCF service library's app.config. The WCF application is set to host the service in IIS7 (the virtual directory has been set). The same solution contains an ASP.NET Webforms solution to which I have added a service reference pointing to the WCF service I hosted in IIS (as mentioned). When i start an instance of this ASP.NET Web application, I get a message saying that "The WCF service has been hosted" and the ASP.NET application can access the data from it correctly. However, when i try and access this data via a service reference added to an MVC 2 Web Application on the same machine in a different solution (pointing to the service hosted in IIS), I get a "The remote server returned an error: (405) Method Not Allowed." protocol exception . However, the MVC application is able to access the service data if I manually invoke an instance of the WCF Application that I was using to host the WCF Service Library from the other solution. I am using VS2010 Beta 2 as my development IDE. I have been stuck with this issue for a while now. Any help would be appreciated. My service config is as follows:- <system.serviceModel> <services> <service behaviorConfiguration="CruxServices.BasicSearchServiceBehavior" name="CruxServices.BasicSearch.BasicSearch"> <endpoint address="" binding="wsHttpBinding" name="WSBindingEndpoint" bindingConfiguration="WSBindingConfig" contract="CruxServices.BasicSearch.Interfaces.IPropertyListFilter"> <identity> <dns value="localhost" /> </identity> </endpoint> <endpoint address="mex" binding="mexHttpBinding" name="MexEndpoint" contract="IMetadataExchange" /> <host> <baseAddresses> <add baseAddress="http://localhost/CruxServices" /> </baseAddresses> </host> </service> </services> <behaviors> <serviceBehaviors> <behavior name="CruxServices.BasicSearchServiceBehavior"> <serviceMetadata httpGetEnabled="true" /> <serviceDebug includeExceptionDetailInFaults="false" /> </behavior> </serviceBehaviors> </behaviors> <bindings> <wsHttpBinding> <binding name="WSBindingConfig"> <security mode="None"> <transport clientCredentialType="None"/> <message establishSecurityContext="false"/> </security> </binding> </wsHttpBinding> </bindings>

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General website publishing questions involving domain forwarding issue

- by Gorgeousyousuf

Even though I have been having a certain level of knowledge and experience about web development I have never interested in obtaining a domain and publishing a website from my own server. Since today I have been struggling with getting my own domain and configuring it utilizing web sources. I started with learning the outline of web publishing process including web server installation, deploying a website for testing purpose,router port forwarding, getting a domain and forwarding domain to my router which will also forward http requests to my web server I am confused about some parts and so far could not get the web site accessed from outside of the network. All I try to do is just for learning purpose so I do not pay much attention to security issues for now. I have Server 2008 and IIS 7.5 installed. I use a laptop and have access to the modem over wireless and my modem is Zoom x6 5590. Well I will continue explaining what I have done so far and what I think will be after each action I did, I have successfully had access to my website on any local computer entering the internal ip address and port pair of the host machine in a browser. Next, I forwarded port 80 of my host machine creating a virtual server like 10.0.0.x(internal ip(static) of the host) - tcp - start port : 80 - end port : 80 in router options. Now I suppose every request that will come to the public Ip on port 80 will be forwarded to my host machine(10.0.0.x) over port 80. So If everyhing went as desired, the website listening on port 80 will accept the request and process the issue and finally respond bla bla bla... I suppose to access my website from outside of the network by entering http://MyPublicIp:80 in a browser but I couldn't accomplish this task by now despite using godady's domain forwarding tool,I see a small view of my website when I click the "preview" button that checks whether the address(http://publicip/Index.aspx) I entered where my domain will be forwarded is available or not. I am sure that configuring domain does not play a role in solving such a problem since using public ip and port matching does not help. So here is the first question, What is the fact that I face this problem? After that, I have couple of question regarding domain forwarding using godaddy tool. Can I forward my domain to a any port for example port 8080 other than default http port 80? Additionally, can I use a sub-domain to forward to a different port of the host? What I want to design is if the client enters www.mydomain.com, website1 will respond over a specified port and after when a client enters info.mydomain.com, another website which listens on different port will respond. I tried to add a sub-domain and forward it to a address like http://www.mydomain.com:8080/Index.aspx with no success. Can I really do that? Finally, what if I have a ftp site listening on the default port 21 and I create a domain like ftp.mydomain.com that will forward to that ftp site address. Is it possible to use sub-domains for ftp site access? I know I am more than confused but no matter whatever and however you reply to me, you will help me have a more clear view on this subject. Thank you very much from now.

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In Ruby, how to I read memory values from an external process?

- by grg-n-sox

So all I simply want to do is make a Ruby program that reads some values from known memory address in another process's virtual memory. Through my research and basic knowledge of hex editing a running process's x86 assembly in memory, I have found the base address and offsets for the values in memory I want. I do not want to change them; I just want to read them. I asked a developer of a memory editor how to approach this abstract of language and assuming a Windows platform. He told me the Win32API calls for OpenProcess, CreateProcess, ReadProcessMemory, and WriteProcessMemory were the way to go using either C or C++. I think that the way to go would be just using the Win32API class and mapping two instances of it; One for either OpenProcess or CreateProcess, depending on if the user already has th process running or not, and another instance will be mapped to ReadProcessMemory. I probably still need to find the function for getting the list of running processes so I know which running process is the one I want if it is running already. This would take some work to put all together, but I am figuring it wouldn't be too bad to code up. It is just a new area of programming for me since I have never worked this low level from a high level language (well, higher level than C anyways). I am just wondering of the ways to approach this. I could just use a bunch or Win32API calls, but that means having to deal with a bunch of string and array pack and unpacking that is system dependant I want to eventually make this work cross-platform since the process I am reading from is produced from an executable that has multiple platform builds, (I know the memory address changes from system to system. The idea is to have a flat file that contains all memory mappings so the Ruby program can just match the current platform environment to the matching memory mapping.) but from the looks of things I'll just have to make a class that wraps whatever is the current platform's system shared library memory related function calls. For all I know, there could already exist a Ruby gem that takes care of all of this for me that I am just not finding. I could also possibly try editing the executables for each build to make it so whenever the memory values I want to read from are written to by the process, it also writes a copy of the new value to a space in shared memory that I somehow have Ruby make an instance of a class that is a pointer under the hood to that shared memory address and somehow signal to the Ruby program that the value was updated and should be reloaded. Basically a interrupt based system would be nice, but since the purpose of reading these values is just to send to a scoreboard broadcasted from a central server, I could just stick to a polling based system that sends updates at fixed time intervals. I also could just abandon Ruby altogether and go for C or C++ but I do not know those nearly as well. I actually know more x86 than C++ and I only know C as far as system independent ANSI C and have never dealt with shared system libraries before. So is there a gem or lesser known module available that has already done this? If not, then any additional information as to how to accomplish this would be nice. I guess, long story short, how do I do all this? Thanks in advance, Grg PS: Also a confirmation that those Win32API calls should be aimed at the kernel32.dll library would be nice.

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Binary Search Tree Implementation

- by Gabe

I've searched the forum, and tried to implement the code in the threads I found. But I've been working on this real simple program since about 10am, and can't solve the seg. faults for the life of me. Any ideas on what I'm doing wrong would be greatly appreciated. BST.h (All the implementation problems should be in here.) #ifndef BST_H_ #define BST_H_ #include <stdexcept> #include <iostream> #include "btnode.h" using namespace std; /* A class to represent a templated binary search tree. */ template <typename T> class BST { private: //pointer to the root node in the tree BTNode<T>* root; public: //default constructor to make an empty tree BST(); /* You have to document these 4 functions */ void insert(T value); bool search(const T& value) const; bool search(BTNode<T>* node, const T& value) const; void printInOrder() const; void remove(const T& value); //function to print out a visual representation //of the tree (not just print the tree's values //on a single line) void print() const; private: //recursive helper function for "print()" void print(BTNode<T>* node,int depth) const; }; /* Default constructor to make an empty tree */ template <typename T> BST<T>::BST() { root = NULL; } template <typename T> void BST<T>::insert(T value) { BTNode<T>* newNode = new BTNode<T>(value); cout << newNode->data; if(root == NULL) { root = newNode; return; } BTNode<T>* current = new BTNode<T>(NULL); current = root; current->data = root->data; while(true) { if(current->left == NULL && current->right == NULL) break; if(current->right != NULL && current->left != NULL) { if(newNode->data > current->data) current = current->right; else if(newNode->data < current->data) current = current->left; } else if(current->right != NULL && current->left == NULL) { if(newNode->data < current->data) break; else if(newNode->data > current->data) current = current->right; } else if(current->right == NULL && current->left != NULL) { if(newNode->data > current->data) break; else if(newNode->data < current->data) current = current->left; } } if(current->data > newNode->data) current->left = newNode; else current->right = newNode; return; } //public helper function template <typename T> bool BST<T>::search(const T& value) const { return(search(root,value)); //start at the root } //recursive function template <typename T> bool BST<T>::search(BTNode<T>* node, const T& value) const { if(node == NULL || node->data == value) return(node != NULL); //found or couldn't find value else if(value < node->data) return search(node->left,value); //search left subtree else return search(node->right,value); //search right subtree } template <typename T> void BST<T>::printInOrder() const { //print out the value's in the tree in order // //You may need to use this function as a helper //and create a second recursive function //(see "print()" for an example) } template <typename T> void BST<T>::remove(const T& value) { if(root == NULL) { cout << "Tree is empty. No removal. "<<endl; return; } if(!search(value)) { cout << "Value is not in the tree. No removal." << endl; return; } BTNode<T>* current; BTNode<T>* parent; current = root; parent->left = NULL; parent->right = NULL; cout << root->left << "LEFT " << root->right << "RIGHT " << endl; cout << root->data << " ROOT" << endl; cout << current->data << "CURRENT BEFORE" << endl; while(current != NULL) { cout << "INTkhkjhbljkhblkjhlk " << endl; if(current->data == value) break; else if(value > current->data) { parent = current; current = current->right; } else { parent = current; current = current->left; } } cout << current->data << "CURRENT AFTER" << endl; // 3 cases : //We're looking at a leaf node if(current->left == NULL && current->right == NULL) // It's a leaf { if(parent->left == current) parent->left = NULL; else parent->right = NULL; delete current; cout << "The value " << value << " was removed." << endl; return; } // Node with single child if((current->left == NULL && current->right != NULL) || (current->left != NULL && current->right == NULL)) { if(current->left == NULL && current->right != NULL) { if(parent->left == current) { parent->left = current->right; cout << "The value " << value << " was removed." << endl; delete current; } else { parent->right = current->right; cout << "The value " << value << " was removed." << endl; delete current; } } else // left child present, no right child { if(parent->left == current) { parent->left = current->left; cout << "The value " << value << " was removed." << endl; delete current; } else { parent->right = current->left; cout << "The value " << value << " was removed." << endl; delete current; } } return; } //Node with 2 children - Replace node with smallest value in right subtree. if (current->left != NULL && current->right != NULL) { BTNode<T>* check; check = current->right; if((check->left == NULL) && (check->right == NULL)) { current = check; delete check; current->right = NULL; cout << "The value " << value << " was removed." << endl; } else // right child has children { //if the node's right child has a left child; Move all the way down left to locate smallest element if((current->right)->left != NULL) { BTNode<T>* leftCurrent; BTNode<T>* leftParent; leftParent = current->right; leftCurrent = (current->right)->left; while(leftCurrent->left != NULL) { leftParent = leftCurrent; leftCurrent = leftCurrent->left; } current->data = leftCurrent->data; delete leftCurrent; leftParent->left = NULL; cout << "The value " << value << " was removed." << endl; } else { BTNode<T>* temp; temp = current->right; current->data = temp->data; current->right = temp->right; delete temp; cout << "The value " << value << " was removed." << endl; } } return; } } /* Print out the values in the tree and their relationships visually. Sample output: 22 18 15 10 9 5 3 1 */ template <typename T> void BST<T>::print() const { print(root,0); } template <typename T> void BST<T>::print(BTNode<T>* node,int depth) const { if(node == NULL) { std::cout << std::endl; return; } print(node->right,depth+1); for(int i=0; i < depth; i++) { std::cout << "\t"; } std::cout << node->data << std::endl; print(node->left,depth+1); } #endif main.cpp #include "bst.h" #include <iostream> using namespace std; int main() { BST<int> tree; cout << endl << "LAB #13 - BINARY SEARCH TREE PROGRAM" << endl; cout << "----------------------------------------------------------" << endl; // Insert. cout << endl << "INSERT TESTS" << endl; // No duplicates allowed. tree.insert(0); tree.insert(5); tree.insert(15); tree.insert(25); tree.insert(20); // Search. cout << endl << "SEARCH TESTS" << endl; int x = 0; int y = 1; if(tree.search(x)) cout << "The value " << x << " is on the tree." << endl; else cout << "The value " << x << " is NOT on the tree." << endl; if(tree.search(y)) cout << "The value " << y << " is on the tree." << endl; else cout << "The value " << y << " is NOT on the tree." << endl; // Removal. cout << endl << "REMOVAL TESTS" << endl; tree.remove(0); tree.remove(1); tree.remove(20); // Print. cout << endl << "PRINTED DIAGRAM OF BINARY SEARCH TREE" << endl; cout << "----------------------------------------------------------" << endl; tree.print(); cout << endl << "Program terminated. Goodbye." << endl << endl; } BTNode.h #ifndef BTNODE_H_ #define BTNODE_H_ #include <iostream> /* A class to represent a node in a binary search tree. */ template <typename T> class BTNode { public: //constructor BTNode(T d); //the node's data value T data; //pointer to the node's left child BTNode<T>* left; //pointer to the node's right child BTNode<T>* right; }; /* Simple constructor. Sets the data value of the BTNode to "d" and defaults its left and right child pointers to NULL. */ template <typename T> BTNode<T>::BTNode(T d) : left(NULL), right(NULL) { data = d; } #endif Thanks.

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XNA: Load and read a XML file?

- by Rosarch

I'm having difficulty doing this seemingly simple task. I want to load XML files with the same ease of loading art assets: content = new ContentManager(Services); content.RootDirectory = "Content"; background = content.Load<Texture2D>("images\\ice"); I'm not sure how to do this. This tutorial seems helpful, but how do I get a StorageDevice instance? I do have something working now, but it feels pretty hacky: public IDictionary<string, string> Get(string typeName) { IDictionary<String, String> result = new Dictionary<String, String>(); xmlReader.Read(); // get past the XML declaration string element = null; string text = null; while (xmlReader.Read()) { switch (xmlReader.NodeType) { case XmlNodeType.Element: element = xmlReader.Name; break; case XmlNodeType.Text: text = xmlReader.Value; break; } if (text != null && element != null) { result[element] = text; text = null; element = null; } } return result; } I apply this to the following XML file: <?xml version="1.0" encoding="utf-8" ?> <zombies> <zombie> <health>100</health> <positionX>23</positionX> <positionY>12</positionY> <speed>2</speed> </zombie> </zombies> And it is able to pass this unit test: internal virtual IPersistentState CreateIPersistentState(string fullpath) { IPersistentState target = new ReadWriteXML(File.Open(fullpath, FileMode.Open)); return target; } /// <summary> ///A test for Get with one zombie. ///</summary> //[TestMethod()] public void SimpleGetTest() { string fullPath = "C:\\pathTo\\Data\\SavedZombies.xml"; IPersistentState target = CreateIPersistentState(fullPath); string typeName = "zombie"; IDictionary<string, string> expected = new Dictionary<string, string>(); expected["health"] = "100"; expected["positionX"] = "23"; expected["positionY"] = "12"; expected["speed"] = "2"; IDictionary<string, string> actual = target.Get(typeName); foreach (KeyValuePair<string, string> entry in expected) { Assert.AreEqual(entry.Value, expected[entry.Key]); } } Downsides to the current approach: file loading is done poorly, and matching keys to values seems like it's way more effort than necessary. Also, I suspect this approach would fall apart with more than one entry in the XML.

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Writing more efficient xquery code (avoiding redundant iteration)

- by Coquelicot

Here's a simplified version of a problem I'm working on: I have a bunch of xml data that encodes information about people. Each person is uniquely identified by an 'id' attribute, but they may go by many names. For example, in one document, I might find <person id=1>Paul Mcartney</person> <person id=2>Ringo Starr</person> And in another I might find: <person id=1>Sir Paul McCartney</person> <person id=2>Richard Starkey</person> I want to use xquery to produce a new document that lists every name associated with a given id. i.e.: <person id=1> <name>Paul McCartney</name> <name>Sir Paul McCartney</name> <name>James Paul McCartney</name> </person> <person id=2> ... </person> The way I'm doing this now in xquery is something like this (pseudocode-esque): let $ids := distinct-terms( [all the id attributes on people] ) for $id in $ids return <person id={$id}> { for $unique-name in distinct-values ( for $name in ( [all names] ) where $name/@id=$id return $name ) return <name>{$unique-name}</name> } </person> The problem is that this is really slow. I imagine the bottleneck is the innermost loop, which executes once for every id (of which there are about 1200). I'm dealing with a fair bit of data (300 MB, spread over about 800 xml files), so even a single execution of the query in the inner loop takes about 12 seconds, which means that repeating it 1200 times will take about 4 hours (which might be optimistic - the process has been running for 3 hours so far). Not only is it slow, it's using a whole lot of virtual memory. I'm using Saxon, and I had to set java's maximum heap size to 10 GB (!) to avoid getting out of memory errors, and it's currently using 6 GB of physical memory. So here's how I'd really like to do this (in Pythonic pseudocode): persons = {} for id in ids: person[id] = set() for person in all_the_people_in_my_xml_document: persons[person.id].add(person.name) There, I just did it in linear time, with only one sweep of the xml document. Now, is there some way to do something similar in xquery? Surely if I can imagine it, a reasonable programming language should be able to do it (he said quixotically). The problem, I suppose, is that unlike Python, xquery doesn't (as far as I know) have anything like an associative array. Is there some clever way around this? Failing that, is there something better than xquery that I might use to accomplish my goal? Because really, the computational resources I'm throwing at this relatively simple problem are kind of ridiculous.

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Blend Interaction Behaviour gives "points to immutable instance" error

- by kennethkryger

I have a UserControl that is a base class for other user controls, that are shown in "modal view". I want to have all user controls fading in, when shown and fading out when closed. I also want a behavior, so that the user can move the controls around.My contructor looks like this: var tg = new TransformGroup(); tg.Children.Add(new ScaleTransform()); RenderTransform = tg; var behaviors = Interaction.GetBehaviors(this); behaviors.Add(new TranslateZoomRotateBehavior()); Loaded += ModalDialogBase_Loaded; And the ModalDialogBase_Loaded method looks like this: private void ModalDialogBase_Loaded(object sender, RoutedEventArgs e) { var fadeInStoryboard = (Storyboard)TryFindResource("modalDialogFadeIn"); fadeInStoryboard.Begin(this); } When I press a Close-button on the control this method is called: protected virtual void Close() { var fadeOutStoryboard = (Storyboard)TryFindResource("modalDialogFadeOut"); fadeOutStoryboard = fadeOutStoryboard.Clone(); fadeOutStoryboard.Completed += delegate { RaiseEvent(new RoutedEventArgs(ClosedEvent)); }; fadeOutStoryboard.Begin(this); } The storyboard for fading out look like this: <Storyboard x:Key="modalDialogFadeOut"> <DoubleAnimationUsingKeyFrames Storyboard.TargetProperty="(UIElement.RenderTransform).(TransformGroup.Children)[0].(ScaleTransform.ScaleX)" Storyboard.TargetName="{x:Null}"> <EasingDoubleKeyFrame KeyTime="0" Value="1"> <EasingDoubleKeyFrame.EasingFunction> <BackEase EasingMode="EaseIn" Amplitude="0.3" /> </EasingDoubleKeyFrame.EasingFunction> </EasingDoubleKeyFrame> <EasingDoubleKeyFrame KeyTime="0:0:0.4" Value="0"> <EasingDoubleKeyFrame.EasingFunction> <BackEase EasingMode="EaseIn" Amplitude="0.3" /> </EasingDoubleKeyFrame.EasingFunction> </EasingDoubleKeyFrame> </DoubleAnimationUsingKeyFrames> <DoubleAnimationUsingKeyFrames Storyboard.TargetProperty="(UIElement.RenderTransform).(TransformGroup.Children)[0].(ScaleTransform.ScaleY)" Storyboard.TargetName="{x:Null}"> <EasingDoubleKeyFrame KeyTime="0" Value="1"> <EasingDoubleKeyFrame.EasingFunction> <BackEase EasingMode="EaseIn" Amplitude="0.3" /> </EasingDoubleKeyFrame.EasingFunction> </EasingDoubleKeyFrame> <EasingDoubleKeyFrame KeyTime="0:0:0.4" Value="0"> <EasingDoubleKeyFrame.EasingFunction> <BackEase EasingMode="EaseIn" Amplitude="0.3" /> </EasingDoubleKeyFrame.EasingFunction> </EasingDoubleKeyFrame> </DoubleAnimationUsingKeyFrames> <DoubleAnimationUsingKeyFrames Storyboard.TargetProperty="(UIElement.Opacity)" Storyboard.TargetName="{x:Null}"> <EasingDoubleKeyFrame KeyTime="0" Value="1" /> <EasingDoubleKeyFrame KeyTime="0:0:0.3" Value="0" /> <EasingDoubleKeyFrame KeyTime="0:0:0.4" Value="0" /> </DoubleAnimationUsingKeyFrames> </Storyboard> If the user control is show, and the user does NOT move it around on the screen, everything works fine. However, if the user DOES move the control around, I get the following error when the modalDialogFadeOut storyboard is started: 'Children' property value in the path '(0).(1)[0].(2)' points to immutable instance of 'System.Windows.Media.TransformCollection'. How can fix this?

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Is the Unix Philosophy still relevant in the Web 2.0 world?

- by David Titarenco

Introduction Hello, let me give you some background before I begin. I started programming when I was 5 or 6 on my dad's PSION II (some primitive BASIC-like language), then I learned more and more, eventually inching my way up to C, C++, Java, PHP, JS, etc. I think I'm a pretty decent coder. I think most people would agree. I'm not a complete social recluse, but I do stuff like write a virtual machine for fun. I've never taken a computer course in college because I've been in and out for the past couple of years and have only been taking core classes; never having been particularly amazing at school, perhaps I'm missing some basic tenet that most learn in CS101. I'm currently reading Coders at Work and this question is based on some ideas I read in there. A Brief (Fictionalized) Example So a certain sunny day I get an idea. I hire a designer and hammer away at some C/C++ code for a couple of months, soon thereafter releasing silvr.com, a website that transmutes lead into silver. Yep, I started my very own start-up and even gave it a clever web 2.0 name with a vowel missing. Mom and dad are proud. I come up with some numbers I should be seeing after 1, 2, 3, 6, 9, 12 months and set sail. Obviously, my transmuting server isn't perfect, sometimes it segfaults, sometimes it leaks memory. I fix it and keep truckin'. After all, gdb is my best friend. Eventually, I'm at a position where a very small community of people are happily transmuting lead into silver on a semi-regular basis, but they want to let their friends on MySpace know how many grams of lead they transmuted today. And they want to post images of their lead and silver nuggets on flickr. I'm losing out on potential traffic unless I let them log in with their Yahoo, Google, and Facebook accounts. They want webcam support and live cock fighting, merry-go-rounds and Jabberwockies. All these things seem necessary. The Aftermath Of course, I have to re-write the transmuting server! After all, I've been losing money all these months. I need OAuth libraries and OpenID libraries, JSON support, and the only stable Jabberwocky API is for Java. C++ isn't even an option anymore. I'm just one guy! The Java binary just grows and grows since I need some legacy Apache include for the JSON library, and some antiquated Sun dependency for OAuth support. Then I pick up a book like Coders at Work and read what people like jwz say about complexity... I think to myself.. Keep it simple, stupid. I like simple things. I've always loved the Unix Philosophy but even after trying to keep the new server source modular and sleek, I loathe having to write one more line of code. It feels that I'm just piling crap on top of other crap. Maybe I'm naive thinking every piece of software can be simple and clever. Maybe it's just a phase.. or is the Unix Philosophy basically dead when it comes to the current state of (web) development? I'm just kind of disheartened :(

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Rendering a view to a string in MVC, then redirecting -- workarounds?

- by James S

Hi -- I can't render a view to a string and then redirect, despite this answer from Feb (after version 1.0, I think) that claims it's possible. I thought I was doing something wrong, and then I read this answer from Haack in July that claims it's not possible. If somebody has it working and can help me get it working, that's great (and I'll post code, errors). However, I'm now at the point of needing workarounds. There are a few, but nothing ideal. Has anybody solved this, or have any comments on my ideas? This is to render email. While I can surely send the email outside of the web request (store info in a db and get it later), there are many types of emails and I don't want to store the template data (user object, a few other LINQ objects) in a db to let it get rendered later. I could create a simpler, serializable POCO and save that in the db, but why? ... I just want rendered text! I can create a new RedirectToAction object that checks if the headers have been sent (can't figure out how to do this -- try/catch?) and, if so, builds out a simple page with a meta redirect, a javascript redirect, and also a "click here" link. Within my controller, I can remember if I've rendered an email and, if so, manually do #2 by displaying a view. I can manually send the redirect headers before any potential email rendering. Then, rather than using the MVC infrastructure to redirecttoaction, I just call result.end. This seems easiest, but really messy. Anything else? EDIT: I've tried Dan's code (very similar to the code from Jan/Feb that I've already tried) and I'm still getting the same error. The only substantial difference I can see is that his example uses a view while I use a partial view. I'll try testing this later with a view. Here's what I've got: Controller public ActionResult Certifications(string email_intro) { //a lot of stuff ViewData["users"] = users; if (isPost()) { //create the viewmodel var view_model = new ViewModels.Emails.Certifications.Open(userContext) { emailIntro = email_intro }; //i've tried stopping this after just one iteration, in case the problem is due to calling it multiple times foreach (var user in users) { if (user.Email_Address.IsValidEmailAddress()) { //add more stuff to the view model specific to this user view_model.user = user; view_model.certification302Summary.subProcessesOwner = new SubProcess_Certifications(RecordUpdating.Role.Owner, null, null, user.User_ID, repository); //more here.... //if i comment out the next line, everything works ok SendEmail(view_model, this.ControllerContext); } } return RedirectToAction("Certifications"); } return View(); } SendEmail() public static void SendEmail(ViewModels.Emails.Certifications.Open model, ControllerContext context) { var vd = context.Controller.ViewData; vd["model"] = model; var renderer = new CustomRenderers(); //i fixed an error in your code here var text = renderer.RenderViewToString3(context, "~/Views/Emails/Certifications/Open.ascx", "", vd, null); var a = text; } CustomRenderers public class CustomRenderers { public virtual string RenderViewToString3(ControllerContext controllerContext, string viewPath, string masterPath, ViewDataDictionary viewData, TempDataDictionary tempData) { //copy/paste of dan's code } } Error [HttpException (0x80004005): Cannot redirect after HTTP headers have been sent.] System.Web.HttpResponse.Redirect(String url, Boolean endResponse) +8707691 Thanks, James

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Java & Tomcat: SQL JDBC/JNDI Exceptions

- by user267581

I am deploying a webapp from eclipse to tomcat. I am having an issue with my application and JNDI lookups. When the app tries to load the JNDI resource I am this stacktrace: javax.naming.ServiceUnavailableException [Root exception is java.rmi.ConnectException: Connection refused to host: localhost; nested exception is: java.net.ConnectException: Connection refused: connect] at com.sun.jndi.rmi.registry.RegistryContext.lookup(RegistryContext.java:101) at javax.naming.InitialContext.lookup(InitialContext.java:396) at org.objectweb.carol.jndi.spi.AbsContext.lookup(AbsContext.java:134) at org.objectweb.carol.jndi.spi.AbsContext.lookup(AbsContext.java:144) at javax.naming.InitialContext.lookup(InitialContext.java:392) at org.objectweb.carol.jndi.spi.MultiContext.lookup(MultiContext.java:118) at javax.naming.InitialContext.lookup(InitialContext.java:392) at com.theriabook.daoflex.JDBCConnection.getDataSource(JDBCConnection.java:61) at com.theriabook.daoflex.JDBCConnection.getConnection(JDBCConnection.java:73) at com.aramark.data.UsersDAO.doLogin(UsersDAO.java:751) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25) at java.lang.reflect.Method.invoke(Method.java:597) at flex.messaging.services.remoting.adapters.JavaAdapter.invoke(JavaAdapter.java:406) at flex.messaging.services.RemotingService.serviceMessage(RemotingService.java:183) at flex.messaging.MessageBroker.routeMessageToService(MessageBroker.java:1417) at flex.messaging.endpoints.AbstractEndpoint.serviceMessage(AbstractEndpoint.java:878) at com.farata.remoting.CustomAMFEndpoint.serviceMessage(CustomAMFEndpoint.java:23) at flex.messaging.endpoints.amf.MessageBrokerFilter.invoke(MessageBrokerFilter.java:121) at flex.messaging.endpoints.amf.LegacyFilter.invoke(LegacyFilter.java:158) at flex.messaging.endpoints.amf.SessionFilter.invoke(SessionFilter.java:49) at flex.messaging.endpoints.amf.BatchProcessFilter.invoke(BatchProcessFilter.java:67) at flex.messaging.endpoints.amf.SerializationFilter.invoke(SerializationFilter.java:146) at flex.messaging.endpoints.BaseHTTPEndpoint.service(BaseHTTPEndpoint.java:274) at flex.messaging.MessageBrokerServlet.service(MessageBrokerServlet.java:377) at javax.servlet.http.HttpServlet.service(HttpServlet.java:717) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:290) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206) at com.cti.compiler.env.web.CompilerInvocationInterceptor.doFilter(CompilerInvocationInterceptor.java:25) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206) at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:233) at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:191) at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:128) at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:102) at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109) at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:286) at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:845) at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:583) at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:447) at java.lang.Thread.run(Thread.java:619) Caused by: java.rmi.ConnectException: Connection refused to host: localhost; nested exception is: java.net.ConnectException: Connection refused: connect at sun.rmi.transport.tcp.TCPEndpoint.newSocket(TCPEndpoint.java:601) at sun.rmi.transport.tcp.TCPChannel.createConnection(TCPChannel.java:198) at sun.rmi.transport.tcp.TCPChannel.newConnection(TCPChannel.java:184) at sun.rmi.server.UnicastRef.newCall(UnicastRef.java:322) at sun.rmi.registry.RegistryImpl_Stub.lookup(Unknown Source) at com.sun.jndi.rmi.registry.RegistryContext.lookup(RegistryContext.java:97) ... 41 more Caused by: java.net.ConnectException: Connection refused: connect at java.net.PlainSocketImpl.socketConnect(Native Method) at java.net.PlainSocketImpl.doConnect(PlainSocketImpl.java:333) at java.net.PlainSocketImpl.connectToAddress(PlainSocketImpl.java:195) at java.net.PlainSocketImpl.connect(PlainSocketImpl.java:182) at java.net.SocksSocketImpl.connect(SocksSocketImpl.java:366) at java.net.Socket.connect(Socket.java:525) at java.net.Socket.connect(Socket.java:475) at java.net.Socket.<init>(Socket.java:372) at java.net.Socket.<init>(Socket.java:186) at sun.rmi.transport.proxy.RMIDirectSocketFactory.createSocket(RMIDirectSocketFactory.java:22) at sun.rmi.transport.proxy.RMIMasterSocketFactory.createSocket(RMIMasterSocketFactory.java:128) at sun.rmi.transport.tcp.TCPEndpoint.newSocket(TCPEndpoint.java:595) I am really stumped at this error. I am using a WinXP running on a Virtual Machine (VMWare) from a MAC. Any ideas? I have uninstalled/reinstalled tomcat multiple times.

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Clear data at serial port in Linux in C?

- by ipkiss

Hello guys, I am testing the sending and receiving programs with the code as The main() function is below: include include include include include include include "read_write.h" int fd; int initport(int fd) { struct termios options; // Get the current options for the port... tcgetattr(fd, &options); // Set the baud rates to 19200... cfsetispeed(&options, B9600); cfsetospeed(&options, B9600); // Enable the receiver and set local mode... options.c_cflag |= (CLOCAL | CREAD); options.c_cflag &= ~PARENB; options.c_cflag &= ~CSTOPB; options.c_cflag &= ~CSIZE; options.c_cflag |= CS8; // Set the new options for the port... tcsetattr(fd, TCSANOW, &options); return 1; } int main(int argc, char **argv) { fd = open("/dev/pts/2", O_RDWR | O_NOCTTY | O_NDELAY); if (fd == -1) { perror("open_port: Unable to open /dev/pts/1 - "); return 1; } else { fcntl(fd, F_SETFL, 0); } printf("baud=%d\n", getbaud(fd)); initport(fd); printf("baud=%d\n", getbaud(fd)); char sCmd[254]; sCmd[0] = 0x41; sCmd[1] = 0x42; sCmd[2] = 0x43; sCmd[3] = 0x00; if (!writeport(fd, sCmd)) { printf("write failed\n"); close(fd); return 1; } printf("written:%s\n", sCmd); usleep(500000); char sResult[254]; fcntl(fd, F_SETFL, FNDELAY); if (!readport(fd,sResult)) { printf("read failed\n"); close(fd); return 1; } printf("readport=%s\n", sResult); close(fd); return 0; } read_write.h: #include <stdio.h> /* Standard input/output definitions */ include /* String function definitions */ include /* UNIX standard function definitions */ include /* File control definitions */ include /* Error number definitions */ include /* POSIX terminal control definitions */ int writeport(int fd, char *chars) { int len = strlen(chars); chars[len] = 0x0d; // stick a after the command chars[len+1] = 0x00; // terminate the string properly int n = write(fd, chars, strlen(chars)); if (n < 0) { fputs("write failed!\n", stderr); return 0; } return 1; } int readport(int fd, char *result) { int iIn = read(fd, result, 254); result[iIn-1] = 0x00; if (iIn < 0) { if (errno == EAGAIN) { printf("SERIAL EAGAIN ERROR\n"); return 0; } else { printf("SERIAL read error %d %s\n", errno, strerror(errno)); return 0; } } return 1; } and got the issue: In order to test with serial port, I used the socat (https://help.ubuntu.com/community/VirtualSerialPort ) to create a pair serial ports on Linux and test my program with these port. The first time the program sends the data and the program receives data is ok. However, if I read again or even re-write the new data into the serial port, the return data is always null until I stop the virtual serial port and start it again, then the write and read data is ok, but still, only one time. (In the real case, the sending part will be done by another device, I am just taking care of the reading data from the serial port. I wrote both parts just to test my reading code.) Does anyone have any ideas? Thanks a lot.

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Compress file to bytes for uploading to SQL Server

- by Chris

I am trying to zip files to an SQL Server database table. I can't ensure that the user of the tool has write priveledges on the source file folder so I want to load the file into memory, compress it to an array of bytes and insert it into my database. This below does not work. class ZipFileToSql { public event MessageHandler Message; protected virtual void OnMessage(string msg) { if (Message != null) { MessageHandlerEventArgs args = new MessageHandlerEventArgs(); args.Message = msg; Message(this, args); } } private int sourceFileId; private SqlConnection Conn; private string PathToFile; private bool isExecuting; public bool IsExecuting { get { return isExecuting; } } public int SourceFileId { get { return sourceFileId; } } public ZipFileToSql(string pathToFile, SqlConnection conn) { isExecuting = false; PathToFile = pathToFile; Conn = conn; } public void Execute() { isExecuting = true; byte[] data; byte[] cmpData; //create temp zip file OnMessage("Reading file to memory"); FileStream fs = File.OpenRead(PathToFile); data = new byte[fs.Length]; ReadWholeArray(fs, data); OnMessage("Zipping file to memory"); MemoryStream ms = new MemoryStream(); GZipStream zip = new GZipStream(ms, CompressionMode.Compress, true); zip.Write(data, 0, data.Length); cmpData = new byte[ms.Length]; ReadWholeArray(ms, cmpData); OnMessage("Saving file to database"); using (SqlCommand cmd = Conn.CreateCommand()) { cmd.CommandText = @"MergeFileUploads"; cmd.CommandType = CommandType.StoredProcedure; //cmd.Parameters.Add("@File", SqlDbType.VarBinary).Value = data; cmd.Parameters.Add("@File", SqlDbType.VarBinary).Value = cmpData; SqlParameter p = new SqlParameter(); p.ParameterName = "@SourceFileId"; p.Direction = ParameterDirection.Output; p.SqlDbType = SqlDbType.Int; cmd.Parameters.Add(p); cmd.ExecuteNonQuery(); sourceFileId = (int)p.Value; } OnMessage("File Saved"); isExecuting = false; } private void ReadWholeArray(Stream stream, byte[] data) { int offset = 0; int remaining = data.Length; float Step = data.Length / 100; float NextStep = data.Length - Step; while (remaining > 0) { int read = stream.Read(data, offset, remaining); if (read <= 0) throw new EndOfStreamException (String.Format("End of stream reached with {0} bytes left to read", remaining)); remaining -= read; offset += read; if (remaining < NextStep) { NextStep -= Step; } } } }

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Architecture for Qt SIGNAL with subclass-specific, templated argument type

- by Barry Wark

I am developing a scientific data acquisition application using Qt. Since I'm not a deep expert in Qt, I'd like some architecture advise from the community on the following problem: The application supports several hardware acquisition interfaces but I would like to provide an common API on top of those interfaces. Each interface has a sample data type and a units for its data. So I'm representing a vector of samples from each device as a std::vector of Boost.Units quantities (i.e. std::vector<boost::units::quantity<unit,sample_type> >). I'd like to use a multi-cast style architecture, where each data source broadcasts newly received data to 1 or more interested parties. Qt's Signal/Slot mechanism is an obvious fit for this style. So, I'd like each data source to emit a signal like typedef std::vector<boost::units::quantity<unit,sample_type> > SampleVector signals: void samplesAcquired(SampleVector sampleVector); for the unit and sample_type appropriate for that device. Since tempalted QObject subclasses aren't supported by the meta-object compiler, there doesn't seem to be a way to have a (tempalted) base class for all data sources which defines the samplesAcquired Signal. In other words, the following won't work: template<T,U> //sample type and units class DataSource : public QObject { Q_OBJECT ... public: typedef std::vector<boost::units::quantity<U,T> > SampleVector signals: void samplesAcquired(SampleVector sampleVector); }; The best option I've been able to come up with is a two-layered approach: template<T,U> //sample type and units class IAcquiredSamples { public: typedef std::vector<boost::units::quantity<U,T> > SampleVector virtual shared_ptr<SampleVector> acquiredData(TimeStamp ts, unsigned long nsamples); }; class DataSource : public QObject { ... signals: void samplesAcquired(TimeStamp ts, unsigned long nsamples); }; The samplesAcquired signal now gives a timestamp and number of samples for the acquisition and clients must use the IAcquiredSamples API to retrieve those samples. Obviously data sources must subclass both DataSource and IAcquiredSamples. The disadvantage of this approach appears to be a loss of simplicity in the API... it would be much nicer if clients could get the acquired samples in the Slot connected. Being able to use Qt's queued connections would also make threading issues easier instead of having to manage them in the acquiredData method within each subclass. One other possibility, is to use a QVariant argument. This necessarily puts the onus on subclass to register their particular sample vector type with Q_REGISTER_METATYPE/qRegisterMetaType. Not really a big deal. Clients of the base class however, will have no way of knowing what type the QVariant value type is, unless a tag struct is also passed with the signal. I consider this solution at least as convoluted as the one above, as it forces clients of the abstract base class API to deal with some of the gnarlier aspects of type system. So, is there a way to achieve the templated signal parameter? Is there a better architecture than the one I've proposed?

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Why so Long time span in creating Session Factory?

- by vijay.shad

Hi My project is web application running in the tomcat container. This application is a spring framework based hibernate application. The problem with this is it takes a lot of time when creates session factory. here is the logs 2010-04-15 23:05:28,053 DEBUG [SessionFactoryImpl] Session factory constructed with filter configurations : {} 2010-04-15 23:05:28,053 DEBUG [SessionFactoryImpl] instantiating session factory with properties: {java.vendor=Sun Microsystems Inc., sun.java.launcher=SUN_STANDARD, catalina.base=/usr/local/InstalledPrograms/apache-tomcat-6.0.20, sun.management.compiler=HotSpot Tiered Compilers, catalina.useNaming=true, os.name=Linux, sun.boot.class.path=/usr/java/jdk1.6.0_17/jre/lib/resources.jar:/usr/java/jdk1.6.0_17/jre/lib/rt.jar:/usr/java/jdk1.6.0_17/jre/lib/sunrsasign.jar:/usr/java/jdk1.6.0_17/jre/lib/jsse.jar:/usr/java/jdk1.6.0_17/jre/lib/jce.jar:/usr/java/jdk1.6.0_17/jre/lib/charsets.jar:/usr/java/jdk1.6.0_17/jre/classes, java.util.logging.config.file=/usr/local/InstalledPrograms/apache-tomcat-6.0.20/conf/logging.properties, java.vm.specification.vendor=Sun Microsystems Inc., hibernate.generate_statistics=true, java.runtime.version=1.6.0_17-b04, hibernate.cache.provider_class=org.hibernate.cache.EhCacheProvider, user.name=root, shared.loader=, tomcat.util.buf.StringCache.byte.enabled=true, hibernate.connection.release_mode=auto, user.language=en, java.naming.factory.initial=org.apache.naming.java.javaURLContextFactory, sun.boot.library.path=/usr/java/jdk1.6.0_17/jre/lib/i386, java.version=1.6.0_17, java.util.logging.manager=org.apache.juli.ClassLoaderLogManager, user.timezone=Canada/Pacific, sun.arch.data.model=32, java.endorsed.dirs=/usr/local/InstalledPrograms/apache-tomcat-6.0.20/endorsed, sun.cpu.isalist=, sun.jnu.encoding=UTF-8, file.encoding.pkg=sun.io, package.access=sun.,org.apache.catalina.,org.apache.coyote.,org.apache.tomcat.,org.apache.jasper.,sun.beans., file.separator=/, java.specification.name=Java Platform API Specification, java.class.version=50.0, user.country=US, java.home=/usr/java/jdk1.6.0_17/jre, java.vm.info=mixed mode, os.version=2.6.18-128.el5, path.separator=:, java.vm.version=14.3-b01, hibernate.jdbc.batch_size=25, java.awt.printerjob=sun.print.PSPrinterJob, sun.io.unicode.encoding=UnicodeLittle, package.definition=sun.,java.,org.apache.catalina.,org.apache.coyote.,org.apache.tomcat.,org.apache.jasper., java.naming.factory.url.pkgs=org.apache.naming, sun.rmi.dgc.client.gcInterval=3600000, user.home=/root, java.specification.vendor=Sun Microsystems Inc., java.library.path=/usr/java/jdk1.6.0_17/jre/lib/i386/server:/usr/java/jdk1.6.0_17/jre/lib/i386:/usr/java/jdk1.6.0_17/jre/../lib/i386:/usr/java/packages/lib/i386:/lib:/usr/lib, java.vendor.url=http://java.sun.com/, java.vm.vendor=Sun Microsystems Inc., hibernate.dialect=org.hibernate.dialect.MySQL5InnoDBDialect, sun.rmi.dgc.server.gcInterval=3600000, common.loader=${catalina.home}/lib,${catalina.home}/lib/*.jar, java.runtime.name=Java(TM) SE Runtime Environment, java.class.path=:/usr/local/InstalledPrograms/apache-tomcat-6.0.20/bin/bootstrap.jar, hibernate.bytecode.use_reflection_optimizer=false, java.vm.specification.name=Java Virtual Machine Specification, java.vm.specification.version=1.0, catalina.home=/usr/local/InstalledPrograms/apache-tomcat-6.0.20, sun.cpu.endian=little, sun.os.patch.level=unknown, hibernate.cache.use_query_cache=true, hibernate.connection.provider_class=org.springframework.orm.hibernate3.LocalDataSourceConnectionProvider, java.io.tmpdir=/usr/local/InstalledPrograms/apache-tomcat-6.0.20/temp, java.vendor.url.bug=http://java.sun.com/cgi-bin/bugreport.cgi, server.loader=, os.arch=i386, java.awt.graphicsenv=sun.awt.X11GraphicsEnvironment, java.ext.dirs=/usr/java/jdk1.6.0_17/jre/lib/ext:/usr/java/packages/lib/ext, user.dir=/, line.separator=, java.vm.name=Java HotSpot(TM) Server VM, hibernate.cache.use_second_level_cache=true, file.encoding=UTF-8, java.specification.version=1.6, hibernate.show_sql=true} 2010-04-15 23:08:53,516 DEBUG [AbstractEntityPersister] Static SQL for entity: com.vsd.model.Order There you can see the time delay of more than 3 mins in executing these processes. My database is mysql and database server is running on the local machine only. The container environment is Centos Linux system. I am clueless about why it takes that much of time in executing these process, But when i do the same task from under eclipse it does not take that much of time. Development environment is Windows.

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Which part of this simple script is breaking internet explorer?

- by user961627

I'm writing a simple virtual keyboard for Arabic (indic) digits. Just links that, when clicked, produce the corresponding Unicode Indic character. The following is my HTML, in the body tag: <a href="#" id='start'>Start</a> <div id='vkb' style='padding:20px;font-size:16pt; border:2px solid #eee; width:250px' dir='ltr'> <a class='key' href='#' id='0'>٠</a> <a class='key' href='#' id='1'>١</a> <a class='key' href='#' id='2'>٢</a> <a class='key' href='#' id='3'>٣</a> <a class='key' href='#' id='4'>٤</a><br /> <a class='key' href='#' id='5'>٥</a> <a class='key' href='#' id='6'>٦</a> <a class='key' href='#' id='7'>٧</a> <a class='key' href='#' id='8'>٨</a> <a class='key' href='#' id='9'>٩</a> <br /> <a href="#" id='stop'>Stop</a> </div> <div id='output' /></div> This is my CSS: a { text-decoration:none; } .key { padding:7px; background-color:#fff; margin:5px; border:2px solid #eee; display:inline-block; } .key:hover { background-color:#eee; } And this is my javascript: <script type="text/javascript" src="js/jquery.js"></script> <script> $(document).ready(function(){ var toprint = ""; $('#vkb').hide(); $('#start').click(function(e){ toprint = ""; $('#vkb').show(); }); $('#stop').click(function(e){ $('#vkb').hide(); ret = ar2ind(toprint); $('#output').text(ret); toprint = ""; }); $('#vkb').click(function(e){ var $key = $(e.target).closest('.key'); var pressed = $key.attr('id'); if(pressed === undefined){ pressed = ""; } toprint = toprint + pressed; }); }); function ar2ind(str) { str = str.replace(/0/g, "?"); str = str.replace(/1/g, "?"); str = str.replace(/2/g, "?"); str = str.replace(/3/g, "?"); str = str.replace(/4/g, "?"); str = str.replace(/5/g, "?"); str = str.replace(/6/g, "?"); str = str.replace(/7/g, "?"); str = str.replace(/8/g, "?"); str = str.replace(/9/g, "?"); return str; } </script> It seems simple enough but it's crashing in IE9. (Might be crashing in earlier versions too but haven't been able to check.)

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Variable mysteriously changing value

- by Eitan

I am making a simple tcp/ip chat program for practicing threads and tcp/ip. I was using asynchronous methods but had a problem with concurrency so I went to threads and blocking methods (not asynchronous). I have two private variables defined in the class, not static: string amessage = string.Empty; int MessageLength; and a Thread private Thread BeginRead; Ok so I call a function called Listen ONCE when the client starts: public virtual void Listen(int byteLength) { var state = new StateObject {Buffer = new byte[byteLength]}; BeginRead = new Thread(ReadThread); BeginRead.Start(state); } and finally the function to receive commands and process them, I'm going to shorten it because it is really long: private void ReadThread(object objectState) { var state = (StateObject)objectState; int byteLength = state.Buffer.Length; while (true) { var buffer = new byte[byteLength]; int len = MySocket.Receive(buffer); if (len <= 0) return; string content = Encoding.ASCII.GetString(buffer, 0, len); amessage += cleanMessage.Substring(0, MessageLength); if (OnRead != null) { var e = new CommandEventArgs(amessage); OnRead(this, e); } } } Now, as I understand it only one thread at a time will enter BeginRead, I call Receive, it blocks until I get data, and then I process it. The problem: the variable amessage will change it's value between statements that do not touch or alter the variable at all, for example at the bottom of the function at: if (OnRead != null) "amessage" will be equal to 'asdf' and at if (OnRead != null) "amessage" will be equal to qwert. As I understand it this is indicative of another thread changing the value/running asynchronously. I only spawn one thread to do the receiving and the Receive function is blocking, how could there be two threads in this function and if there is only one thread how does amessage's value change between statements that don't affect it's value. As a side note sorry for spamming the site with these questions but I'm just getting a hang of this threading story and it's making me want to sip cyanide. Thanks in advance. EDIT: Here is my code that calls the Listen Method in the client: public void ConnectClient(string ip,int port) { client.Connect(ip,port); client.Listen(5); } and in the server: private void Accept(IAsyncResult result) { var client = new AbstractClient(MySocket.EndAccept(result)); var e = new CommandEventArgs(client, null); Clients.Add(client); client.Listen(5); if (OnClientAdded != null) { var target = (Control) OnClientAdded.Target; if (target != null && target.InvokeRequired) target.Invoke(OnClientAdded, this, e); else OnClientAdded(this, e); } client.OnRead += OnRead; MySocket.BeginAccept(new AsyncCallback(Accept), null); } All this code is in a class called AbstractClient. The client inherits the Abstract client and when the server accepts a socket it create's it's own local AbstractClient, in this case both modules access the functions above however they are different instances and I couldn't imagine threads from different instances combining especially as no variable is static.

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XNA: Best way to load and read a XML file?

- by Rosarch

I'm having difficulty doing this seemingly simple task. I want to load XML files with the same ease of loading art assets: content = new ContentManager(Services); content.RootDirectory = "Content"; Texture2d background = content.Load<Texture2D>("images\\ice"); I'm not sure how to do this. This tutorial seems helpful, but how do I get a StorageDevice instance? I do have something working now, but it feels pretty hacky: public IDictionary<string, string> Get(string typeName) { IDictionary<String, String> result = new Dictionary<String, String>(); xmlReader.Read(); // get past the XML declaration string element = null; string text = null; while (xmlReader.Read()) { switch (xmlReader.NodeType) { case XmlNodeType.Element: element = xmlReader.Name; break; case XmlNodeType.Text: text = xmlReader.Value; break; } if (text != null && element != null) { result[element] = text; text = null; element = null; } } return result; } I apply this to the following XML file: <?xml version="1.0" encoding="utf-8" ?> <zombies> <zombie> <health>100</health> <positionX>23</positionX> <positionY>12</positionY> <speed>2</speed> </zombie> </zombies> And it is able to pass this unit test: internal virtual IPersistentState CreateIPersistentState(string fullpath) { IPersistentState target = new ReadWriteXML(File.Open(fullpath, FileMode.Open)); return target; } /// <summary> ///A test for Get with one zombie. ///</summary> //[TestMethod()] public void SimpleGetTest() { string fullPath = "C:\\pathTo\\Data\\SavedZombies.xml"; IPersistentState target = CreateIPersistentState(fullPath); string typeName = "zombie"; IDictionary<string, string> expected = new Dictionary<string, string>(); expected["health"] = "100"; expected["positionX"] = "23"; expected["positionY"] = "12"; expected["speed"] = "2"; IDictionary<string, string> actual = target.Get(typeName); foreach (KeyValuePair<string, string> entry in expected) { Assert.AreEqual(entry.Value, expected[entry.Key]); } } Downsides to the current approach: file loading is done poorly, and matching keys to values seems like it's way more effort than necessary. Also, I suspect this approach would fall apart with more than one entry in the XML. I can't imagine that this is the optimal implementation.

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[C#] Not enough memory or not enough handles?

- by Nayan

I am working on a large scale project where a custom (pretty good and robust) framework has been provided and we have to use that for showing up forms and views. There is abstract class StrategyEditor (derived from some class in framework) which is instantiated whenever a new StrategyForm is opened. StrategyForm (a customized window frame) contains StrategyEditor. StrategyEditor contains StrategyTab. StrategyTab contains StrategyCanvas. This is a small portion of the big classes to clarify that there are many objects that will be created if one StrategyForm object is allocated in memory at run-time. My component owns all these classes mentioned above except StrategyForm whose code is not in my control. Now, at run-time, user opens up many strategy objects (which trigger creation of new StrategyForm object.) After creating approx. 44 strategy objects, we see that the USER OBJECT HANDLES (I'll use UOH from here onwards) created by the application reaches to about 20k+, while in registry the default amount for handles is 10k. Read more about User Objects here. Testing on different machines made it clear that the number of strategy objects opened is different for message to pop-up - on one m/c if it is 44, then it can be 40 on another. When we see the message pop-up, it means that the application is going to respond slowly. It gets worse with few more objects and then creation of window frames and subsequent objects fail. We first thought that it was not-enough-memory issue. But then reading more about new in C# helped in understanding that an exception would be thrown if app ran out of memory. This is not a memory issue then, I feel (task manager also showed 1.5GB+ available memory.) M/C specs Core 2 Duo 2GHz+ 4GB RAM 80GB+ free disk space for page file Virtual Memory set: 4000 - 6000 My questions Q1. Does this look like a memory issue and I am wrong that it is not? Q2. Does this point to exhaustion of free UOHs (as I'm thinking) and which is resulting in failure of creation of window handles? Q3. How can we avoid loading up of an StrategyEditor object (beyond a threshold, keeping an eye on the current usage of UOHs)? (we already know how to fetch number of UOHs in use, so don't go there.) Keep in mind that the call to new StrategyForm() is outside the control of my component. Q4. I am bit confused - what are Handles to user objects exactly? Is MSDN talking about any object that we create or only some specific objects like window handles, cursor handles, icon handles? Q5. What exactly cause to use up a UOH? (almost same as Q4) I would be really thankful to anyone who can give me some knowledgeable answers. Thanks much! :)

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Random Complete System Unresponsiveness Running Mathematical Functions

- by Computer Guru

I have a program that loads a file (anywhere from 10MB to 5GB) a chunk at a time (ReadFile), and for each chunk performs a set of mathematical operations (basically calculates the hash). After calculating the hash, it stores info about the chunk in an STL map (basically <chunkID, hash>) and then writes the chunk itself to another file (WriteFile). That's all it does. This program will cause certain PCs to choke and die. The mouse begins to stutter, the task manager takes 2 min to show, ctrl+alt+del is unresponsive, running programs are slow.... the works. I've done literally everything I can think of to optimize the program, and have triple-checked all objects. What I've done: Tried different (less intensive) hashing algorithms. Switched all allocations to nedmalloc instead of the default new operator Switched from stl::map to unordered_set, found the performance to still be abysmal, so I switched again to Google's dense_hash_map. Converted all objects to store pointers to objects instead of the objects themselves. Caching all Read and Write operations. Instead of reading a 16k chunk of the file and performing the math on it, I read 4MB into a buffer and read 16k chunks from there instead. Same for all write operations - they are coalesced into 4MB blocks before being written to disk. Run extensive profiling with Visual Studio 2010, AMD Code Analyst, and perfmon. Set the thread priority to THREAD_MODE_BACKGROUND_BEGIN Set the thread priority to THREAD_PRIORITY_IDLE Added a Sleep(100) call after every loop. Even after all this, the application still results in a system-wide hang on certain machines under certain circumstances. Perfmon and Process Explorer show minimal CPU usage (with the sleep), no constant reads/writes from disk, few hard pagefaults (and only ~30k pagefaults in the lifetime of the application on a 5GB input file), little virtual memory (never more than 150MB), no leaked handles, no memory leaks. The machines I've tested it on run Windows XP - Windows 7, x86 and x64 versions included. None have less than 2GB RAM, though the problem is always exacerbated under lower memory conditions. I'm at a loss as to what to do next. I don't know what's causing it - I'm torn between CPU or Memory as the culprit. CPU because without the sleep and under different thread priorities the system performances changes noticeably. Memory because there's a huge difference in how often the issue occurs when using unordered_set vs Google's dense_hash_map. What's really weird? Obviously, the NT kernel design is supposed to prevent this sort of behavior from ever occurring (a user-mode application driving the system to this sort of extreme poor performance!?)..... but when I compile the code and run it on OS X or Linux (it's fairly standard C++ throughout) it performs excellently even on poor machines with little RAM and weaker CPUs. What am I supposed to do next? How do I know what the hell it is that Windows is doing behind the scenes that's killing system performance, when all the indicators are that the application itself isn't doing anything extreme? Any advice would be most welcome.

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(static initialization order?!) problems with factory pattern

- by smerlin

Why does following code raise an exception (in createObjects call to map::at) alternativly the code (and its output) can be viewed here intererestingly the code works as expected if the commented lines are uncommented with both microsoft and gcc compiler (see here), this even works with initMap as ordinary static variable instead of static getter. The only reason for this i can think of is that the order of initialization of the static registerHelper_ object (factory_helper_)and the std::map object (initMap) are wrong, however i cant see how that could happen, because the map object is constructed on first usage and thats in factory_helper_ constructor, so everything should be alright shouldnt it ? I am even more suprised that those doNothing() lines fix the issue, because that call to doNothing() would happen after the critical section (which currently fails) is passed anyway. EDIT: debugging showed, that without the call to factory_helper_.doNothing(), the constructor of factory_helper_ is never called. #include <iostream> #include <string> #include <map> #define FACTORY_CLASS(classtype) \ extern const char classtype##_name_[] = #classtype; \ class classtype : FactoryBase<classtype,classtype##_name_> namespace detail_ { class registerHelperBase { public: registerHelperBase(){} protected: static std::map<std::string, void * (*)(void)>& getInitMap() { static std::map<std::string, void * (*)(void)>* initMap = 0; if(!initMap) initMap= new std::map<std::string, void * (*)(void)>(); return *initMap; } }; template<class TParent, const char* ClassName> class registerHelper_ : registerHelperBase { static registerHelper_ help_; public: //void doNothing(){} registerHelper_(){ getInitMap()[std::string(ClassName)]=&TParent::factory_init_; } }; template<class TParent, const char* ClassName> registerHelper_<TParent,ClassName> registerHelper_<TParent,ClassName>::help_; } class Factory : detail_::registerHelperBase { private: Factory(); public: static void* createObject(const std::string& objclassname) { return getInitMap().at(objclassname)(); } }; template <class TClass, const char* ClassName> class FactoryBase { private: static detail_::registerHelper_<FactoryBase<TClass,ClassName>,ClassName> factory_helper_; static void* factory_init_(){ return new TClass();} public: friend class detail_::registerHelper_<FactoryBase<TClass,ClassName>,ClassName>; FactoryBase(){ //factory_helper_.doNothing(); } virtual ~FactoryBase(){}; }; template <class TClass, const char* ClassName> detail_::registerHelper_<FactoryBase<TClass,ClassName>,ClassName> FactoryBase<TClass,ClassName>::factory_helper_; FACTORY_CLASS(Test) { public: Test(){} }; int main(int argc, char** argv) { try { Test* test = (Test*) Factory::createObject("Test"); } catch(const std::exception& ex) { std::cerr << "caught std::exception: "<< ex.what() << std::endl; } #ifdef _MSC_VER system("pause"); #endif return 0; }

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Ruby on Rails is complaining about a method that doesn't exist that is built into Active Record. Wha

- by grg-n-sox

This will probably just be a simple problem and I am just blind or an idiot but I could use some help. So I am going over some basic guides in Rails, reviewing the basics and such for an upcoming exam. One of the guides included was the sort-of-standard getting started guide over at guide.rubyonrails.org. Here is the link if you need it. Also all my code is for my app is from there, so I have no problem releasing any of my code since it should be the same as shown there. I didn't do a copy paste, but I basically was typing with Vim in one half of my screen and the web page in the other half, typing what I see. http://guides.rubyonrails.org/getting_started.html So like I said, I am going along the guide when I noticed past a certain point in the tutorial, I was always getting an error on the site. To find the section of code, just hit Ctrl+f on the page (or whatever you have search/find set to) and enter "accepts_". This should immediately direct you to this chunk of code. class Post < ActiveRecord::Base validates_presence_of :name, :title validates_length_of :title, :minimum => 5 has_many :comments has_many :tags accepts_nested_attributes_for :tags, :allow_destroy => :true , :reject_if => proc { |attrs| attrs.all? { |k, v| v.blank? } } end So I tried putting this in my code. It is in ~/Rails/blog/app/models/post.rb in case you are wondering. However, even after all the other code I put in past that in the guide, hoping I was just missing some line of code that would come up later in the guide. But nothing, same error every time. This is what I get. NoMethodError in PostsController#index undefined method `accepts_nested_attributes_for' for #<Class:0xb7109f98> /usr/lib/ruby/gems/1.8/gems/activerecord-2.2.2/lib/active_record/base.rb:1833:in `method_missing' app/models/post.rb:7 app/controllers/posts_controller.rb:9:in `index' Request Parameters: None Response Headers: {"Content-Type"=>"", "cookie"=>[], "Cache-Control"=>"no-cache"} Now, I copied the above code from the guide. The two code sections I edited mentioned in the error message I will paste as is below. class PostsController < ApplicationController # GET /posts # GET /posts.xml before_filter :find_post, :only => [:show, :edit, :update, :destroy] def index @posts = Post.find(:all) # <= the line 9 referred to in error message respond_to do |format| format.html # index.html.erb format.xml { render :xml => @posts } end end class Post < ActiveRecord::Base validates_presence_of :name, :title validates_length_of :title, :minimum => 5 has_many :comments has_many :tags accepts_nested_attributes_for :tags, :allow_destroy => :true , # <= problem :reject_if => proc { |attrs| attrs.all? { |k, v| v.blank? } } end Also here is gem local gem list. I do note that they are a bit out of date, but the default Rails install any of the school machines (an environment likely for my exam) is basically 'gem install rails --version 2.2.2' and since they are windows machines, they come with all the normal windows ruby gems that comes with the ruby installer. However, I am running this off a Debian virtual machine of mine, but trying to set it up similarly and I figured the windows ruby gems wouldn't change anything in Rails. *** LOCAL GEMS *** actionmailer (2.2.2) actionpack (2.2.2) activerecord (2.2.2) activeresource (2.2.2) activesupport (2.2.2) gem_plugin (0.2.3) hpricot (0.8.2) linecache (0.43) log4r (1.1.7) ptools (1.1.9) rack (1.1.0) rails (2.2.2) rake (0.8.7) sqlite3-ruby (1.2.3) So any ideas on what the problem is? Thanks in advanced.

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Two-way databinding of a custom templated control. Eval works, but not Bind.

- by Jason

I hate long code snippets and I'm sorry about this one, but it turns out that this asp.net stuff can't get much shorter and it's so specific that I haven't been able to generalize it without a full code listing. I just want simple two-way, declarative databinding to a single instance of an object. Not a list of objects of a type with a bunch of NotImplementedExceptions for Add, Delete, and Select, but just a single view-state persisted object. This is certainly something that can be done but I've struggled with an implementation for years. This newest, closest implementation was inspired by this article from 4-Guys-From-Rolla, http://msdn.microsoft.com/en-us/library/aa478964.aspx. Unfortunately, after implementing, I'm getting the following error and I don't know what I'm missing: System.InvalidOperationException: Databinding methods such as Eval(), XPath(), and Bind() can only be used in the context of a databound control. If I don't use Bind(), and only use Eval() functionality, it works. In that way, the error is especially confusing. Here's the simplified codeset that still produces the error: using System.ComponentModel; namespace System.Web.UI.WebControls.Special { public class SampleFormData { public string SampleString = "Sample String Data"; public int SampleInt = -1; } [ToolboxItem(false)] public class SampleSpecificFormDataContainer : WebControl, INamingContainer { SampleSpecificEntryForm entryForm; internal SampleSpecificEntryForm EntryForm { get { return entryForm; } } [Bindable(true), Category("Data")] public string SampleString { get { return entryForm.FormData.SampleString; } set { entryForm.FormData.SampleString = value; } } [Bindable(true), Category("Data")] public int SampleInt { get { return entryForm.FormData.SampleInt; } set { entryForm.FormData.SampleInt = value; } } internal SampleSpecificFormDataContainer(SampleSpecificEntryForm entryForm) { this.entryForm = entryForm; } } public class SampleSpecificEntryForm : WebControl, INamingContainer { #region Template private IBindableTemplate formTemplate = null; [Browsable(false), DefaultValue(null), TemplateContainer(typeof(SampleSpecificFormDataContainer), ComponentModel.BindingDirection.TwoWay), PersistenceMode(PersistenceMode.InnerProperty)] public virtual IBindableTemplate FormTemplate { get { return formTemplate; } set { formTemplate = value; } } #endregion #region Viewstate SampleFormData FormDataVS { get { return (ViewState["FormData"] as SampleFormData) ?? new SampleFormData(); } set { ViewState["FormData"] = value; SaveViewState(); } } #endregion public override ControlCollection Controls { get { EnsureChildControls(); return base.Controls; } } private SampleSpecificFormDataContainer formDataContainer = null; [Browsable(false), DesignerSerializationVisibility(DesignerSerializationVisibility.Hidden)] public SampleSpecificFormDataContainer FormDataContainer { get { EnsureChildControls(); return formDataContainer; } } [Bindable(true), Browsable(false)] public SampleFormData FormData { get { return FormDataVS; } set { FormDataVS = value; } } protected override void CreateChildControls() { if (!this.ChildControlsCreated) { Controls.Clear(); formDataContainer = new SampleSpecificFormDataContainer(this); Controls.Add(formDataContainer); FormTemplate.InstantiateIn(formDataContainer); this.ChildControlsCreated = true; } } public override void DataBind() { CreateChildControls(); base.DataBind(); } } } With an ASP.NET page the following: <%@ Page Title="Home Page" Language="C#" MasterPageFile="~/Site.master" AutoEventWireup="true" CodeBehind="Default2.aspx.cs" Inherits="EntryFormTest._Default2" EnableEventValidation="false" %> <%@ Register Assembly="EntryForm" Namespace="System.Web.UI.WebControls.Special" TagPrefix="cc1" %> <asp:Content ID="HeaderContent" runat="server" ContentPlaceHolderID="HeadContent"> </asp:Content> <asp:Content ID="BodyContent" runat="server" ContentPlaceHolderID="MainContent"> <h2> Welcome to ASP.NET! </h2> <cc1:SampleSpecificEntryForm ID="EntryForm1" runat="server"> <FormTemplate> <asp:TextBox ID="TextBox1" runat="server" Text='<%# Bind("SampleString") %>'></asp:TextBox><br /> <h3>(<%# Container.SampleString %>)</h3><br /> <asp:Button ID="Button1" runat="server" Text="Button" /> </FormTemplate> </cc1:SampleSpecificEntryForm> </asp:Content> Default2.aspx.cs using System; namespace EntryFormTest { public partial class _Default2 : System.Web.UI.Page { protected void Page_Load(object sender, EventArgs e) { EntryForm1.DataBind(); } } } Thanks for any help!

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Languages and VMs: Features that are hard to optimize and why

- by mrjoltcola

I'm doing a survey of features in preparation for a research project. Name a mainstream language or language feature that is hard to optimize, and why the feature is or isn't worth the price paid, or instead, just debunk my theories below with anecdotal evidence. Before anyone flags this as subjective, I am asking for specific examples of languages or features, and ideas for optimization of these features, or important features that I haven't considered. Also, any references to implementations that prove my theories right or wrong. Top on my list of hard to optimize features and my theories (some of my theories are untested and are based on thought experiments): 1) Runtime method overloading (aka multi-method dispatch or signature based dispatch). Is it hard to optimize when combined with features that allow runtime recompilation or method addition. Or is it just hard, anyway? Call site caching is a common optimization for many runtime systems, but multi-methods add additional complexity as well as making it less practical to inline methods. 2) Type morphing / variants (aka value based typing as opposed to variable based) Traditional optimizations simply cannot be applied when you don't know if the type of someting can change in a basic block. Combined with multi-methods, inlining must be done carefully if at all, and probably only for a given threshold of size of the callee. ie. it is easy to consider inlining simple property fetches (getters / setters) but inlining complex methods may result in code bloat. The other issue is I cannot just assign a variant to a register and JIT it to the native instructions because I have to carry around the type info, or every variable needs 2 registers instead of 1. On IA-32 this is inconvenient, even if improved with x64's extra registers. This is probably my favorite feature of dynamic languages, as it simplifies so many things from the programmer's perspective. 3) First class continuations - There are multiple ways to implement them, and I have done so in both of the most common approaches, one being stack copying and the other as implementing the runtime to use continuation passing style, cactus stacks, copy-on-write stack frames, and garbage collection. First class continuations have resource management issues, ie. we must save everything, in case the continuation is resumed, and I'm not aware if any languages support leaving a continuation with "intent" (ie. "I am not coming back here, so you may discard this copy of the world"). Having programmed in the threading model and the contination model, I know both can accomplish the same thing, but continuations' elegance imposes considerable complexity on the runtime and also may affect cache efficienty (locality of stack changes more with use of continuations and co-routines). The other issue is they just don't map to hardware. Optimizing continuations is optimizing for the less-common case, and as we know, the common case should be fast, and the less-common cases should be correct. 4) Pointer arithmetic and ability to mask pointers (storing in integers, etc.) Had to throw this in, but I could actually live without this quite easily. My feelings are that many of the high-level features, particularly in dynamic languages just don't map to hardware. Microprocessor implementations have billions of dollars of research behind the optimizations on the chip, yet the choice of language feature(s) may marginalize many of these features (features like caching, aliasing top of stack to register, instruction parallelism, return address buffers, loop buffers and branch prediction). Macro-applications of micro-features don't necessarily pan out like some developers like to think, and implementing many languages in a VM ends up mapping native ops into function calls (ie. the more dynamic a language is the more we must lookup/cache at runtime, nothing can be assumed, so our instruction mix is made up of a higher percentage of non-local branching than traditional, statically compiled code) and the only thing we can really JIT well is expression evaluation of non-dynamic types and operations on constant or immediate types. It is my gut feeling that bytecode virtual machines and JIT cores are perhaps not always justified for certain languages because of this. I welcome your answers.

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