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  • Need to capture and store receiver's details via IPN by using Paypal Mass Pay API

    - by Devner
    Hi all, This is a question about Paypal Mass Pay IPN. My platform is PHP & mySQL. All over the Paypal support website, I have found IPN for only payments made. I need an IPN on similar lines for Mass Pay but could not find it. Also tried experimenting with already existing Mass Pay NVP code, but that did not work either. What I am trying to do is that for all the recipients to whom the payment has been successfully sent via Mass Pay, I want to record their email, amount and unique_id in my own database table. If possible, I want to capture the payment status as well, whether it has been a success of failure and based upon the same, I need to do some in house processing. The existing code Mass pay code is below: <?php $environment = 'sandbox'; // or 'beta-sandbox' or 'live' /** * Send HTTP POST Request * * @param string The API method name * @param string The POST Message fields in &name=value pair format * @return array Parsed HTTP Response body */ function PPHttpPost($methodName_, $nvpStr_) { global $environment; // Set up your API credentials, PayPal end point, and API version. $API_UserName = urlencode('my_api_username'); $API_Password = urlencode('my_api_password'); $API_Signature = urlencode('my_api_signature'); $API_Endpoint = "https://api-3t.paypal.com/nvp"; if("sandbox" === $environment || "beta-sandbox" === $environment) { $API_Endpoint = "https://api-3t.$environment.paypal.com/nvp"; } $version = urlencode('51.0'); // Set the curl parameters. $ch = curl_init(); curl_setopt($ch, CURLOPT_URL, $API_Endpoint); curl_setopt($ch, CURLOPT_VERBOSE, 1); // Turn off the server and peer verification (TrustManager Concept). curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, FALSE); curl_setopt($ch, CURLOPT_SSL_VERIFYHOST, FALSE); curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1); curl_setopt($ch, CURLOPT_POST, 1); // Set the API operation, version, and API signature in the request. $nvpreq = "METHOD=$methodName_&VERSION=$version&PWD=$API_Password&USER=$API_UserName&SIGNATURE=$API_Signature$nvpStr_"; // Set the request as a POST FIELD for curl. curl_setopt($ch, CURLOPT_POSTFIELDS, $nvpreq); // Get response from the server. $httpResponse = curl_exec($ch); if(!$httpResponse) { exit("$methodName_ failed: ".curl_error($ch).'('.curl_errno($ch).')'); } // Extract the response details. $httpResponseAr = explode("&", $httpResponse); $httpParsedResponseAr = array(); foreach ($httpResponseAr as $i => $value) { $tmpAr = explode("=", $value); if(sizeof($tmpAr) > 1) { $httpParsedResponseAr[$tmpAr[0]] = $tmpAr[1]; } } if((0 == sizeof($httpParsedResponseAr)) || !array_key_exists('ACK', $httpParsedResponseAr)) { exit("Invalid HTTP Response for POST request($nvpreq) to $API_Endpoint."); } return $httpParsedResponseAr; } // Set request-specific fields. $emailSubject =urlencode('example_email_subject'); $receiverType = urlencode('EmailAddress'); $currency = urlencode('USD'); // or other currency ('GBP', 'EUR', 'JPY', 'CAD', 'AUD') // Add request-specific fields to the request string. $nvpStr="&EMAILSUBJECT=$emailSubject&RECEIVERTYPE=$receiverType&CURRENCYCODE=$currency"; $receiversArray = array(); for($i = 0; $i < 3; $i++) { $receiverData = array( 'receiverEmail' => "[email protected]", 'amount' => "example_amount", 'uniqueID' => "example_unique_id", 'note' => "example_note"); $receiversArray[$i] = $receiverData; } foreach($receiversArray as $i => $receiverData) { $receiverEmail = urlencode($receiverData['receiverEmail']); $amount = urlencode($receiverData['amount']); $uniqueID = urlencode($receiverData['uniqueID']); $note = urlencode($receiverData['note']); $nvpStr .= "&L_EMAIL$i=$receiverEmail&L_Amt$i=$amount&L_UNIQUEID$i=$uniqueID&L_NOTE$i=$note"; } // Execute the API operation; see the PPHttpPost function above. $httpParsedResponseAr = PPHttpPost('MassPay', $nvpStr); if("SUCCESS" == strtoupper($httpParsedResponseAr["ACK"]) || "SUCCESSWITHWARNING" == strtoupper($httpParsedResponseAr["ACK"])) { exit('MassPay Completed Successfully: '.print_r($httpParsedResponseAr, true)); } else { exit('MassPay failed: ' . print_r($httpParsedResponseAr, true)); } ?> In the code above, how and where do I add code to capture the fields that I requested above? Any code indicating the solution is highly appreciated. Thank you very much.

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  • Error when pushing to Heroku - ...appear in group - Ruby on Rails

    - by bgadoci
    I am trying to deploy my first rails app to Heroku and seem to be having a problem. After git push heroku master, and heroku rake db:migrate I get an error saying: SELECT posts.*, count(*) as vote_total FROM "posts" INNER JOIN "votes" ON votes.post_id = posts.id GROUP BY votes.post_id ORDER BY created_at DESC LIMIT 5 OFFSET 0): I have included the full error below and also included the PostControll#index as it seems that is where I am doing the grouping. Lastly I included my routes.rb file. I am new to ruby, rails, and heroku so sorry for simple/obvious questions. Processing PostsController#index (for 99.7.50.140 at 2010-04-21 12:50:47) [GET] ActiveRecord::StatementInvalid (PGError: ERROR: column "posts.id" must appear in the GROUP BY clause or be used in an aggregate function : SELECT posts.*, count(*) as vote_total FROM "posts" INNER JOIN "votes" ON votes.post_id = posts.id GROUP BY votes.post_id ORDER BY created_at DESC LIMIT 5 OFFSET 0): vendor/gems/will_paginate-2.3.12/lib/will_paginate/finder.rb:82:in `send' vendor/gems/will_paginate-2.3.12/lib/will_paginate/finder.rb:82:in `paginate' vendor/gems/will_paginate-2.3.12/lib/will_paginate/collection.rb:87:in `create' vendor/gems/will_paginate-2.3.12/lib/will_paginate/finder.rb:76:in `paginate' app/controllers/posts_controller.rb:28:in `index' /home/heroku_rack/lib/static_assets.rb:9:in `call' /home/heroku_rack/lib/last_access.rb:25:in `call' /home/heroku_rack/lib/date_header.rb:14:in `call' thin (1.0.1) lib/thin/connection.rb:80:in `pre_process' thin (1.0.1) lib/thin/connection.rb:78:in `catch' thin (1.0.1) lib/thin/connection.rb:78:in `pre_process' thin (1.0.1) lib/thin/connection.rb:57:in `process' thin (1.0.1) lib/thin/connection.rb:42:in `receive_data' eventmachine (0.12.6) lib/eventmachine.rb:240:in `run_machine' eventmachine (0.12.6) lib/eventmachine.rb:240:in `run' thin (1.0.1) lib/thin/backends/base.rb:57:in `start' thin (1.0.1) lib/thin/server.rb:150:in `start' thin (1.0.1) lib/thin/controllers/controller.rb:80:in `start' thin (1.0.1) lib/thin/runner.rb:173:in `send' thin (1.0.1) lib/thin/runner.rb:173:in `run_command' thin (1.0.1) lib/thin/runner.rb:139:in `run!' thin (1.0.1) bin/thin:6 /usr/local/bin/thin:20:in `load' /usr/local/bin/thin:20 PostsController def index @tag_counts = Tag.count(:group => :tag_name, :order => 'count_all DESC', :limit => 20) conditions, joins = {}, :votes @ugtag_counts = Ugtag.count(:group => :ugctag_name, :order => 'count_all DESC', :limit => 20) conditions, joins = {}, :votes @vote_counts = Vote.count(:group => :post_title, :order => 'count_all DESC', :limit => 20) conditions, joins = {}, :votes unless(params[:tag_name] || "").empty? conditions = ["tags.tag_name = ? ", params[:tag_name]] joins = [:tags, :votes] end @posts=Post.paginate( :select => "posts.*, count(*) as vote_total", :joins => joins, :conditions=> conditions, :group => "votes.post_id", :order => "created_at DESC", :page => params[:page], :per_page => 5) @popular_posts=Post.paginate( :select => "posts.*, count(*) as vote_total", :joins => joins, :conditions=> conditions, :group => "votes.post_id", :order => "vote_total DESC", :page => params[:page], :per_page => 3) respond_to do |format| format.html # index.html.erb format.xml { render :xml => @posts } format.json { render :json => @posts } format.atom end end routes.rb ActionController::Routing::Routes.draw do |map| map.resources :ugtags map.resources :wysihat_files map.resources :users map.resources :votes map.resources :votes, :belongs_to => :user map.resources :tags, :belongs_to => :user map.resources :ugtags, :belongs_to => :user map.resources :posts, :collection => {:auto_complete_for_tag_tag_name => :get } map.resources :posts, :sessions map.resources :posts, :has_many => :comments map.resources :posts, :has_many => :tags map.resources :posts, :has_many => :ugtags map.resources :posts, :has_many => :votes map.resources :posts, :belongs_to => :user map.resources :tags, :collection => {:auto_complete_for_tag_tag_name => :get } map.resources :ugtags, :collection => {:auto_complete_for_ugtag_ugctag_name => :get } map.login 'login', :controller => 'sessions', :action => 'new' map.logout 'logout', :controller => 'sessions', :action => 'destroy' map.root :controller => "posts" map.connect ':controller/:action/:id' map.connect ':controller/:action/:id.:format' end UPDATE TO SHOW MODEL AND MIGRATION FOR POST class Post < ActiveRecord::Base has_attached_file :photo validates_presence_of :body, :title has_many :comments, :dependent => :destroy has_many :tags, :dependent => :destroy has_many :ugtags, :dependent => :destroy has_many :votes, :dependent => :destroy belongs_to :user after_create :self_vote def self_vote # I am assuming you have a user_id field in `posts` and `votes` table. self.votes.create(:user => self.user) end cattr_reader :per_page @@per_page = 10 end migrations for post class CreatePosts < ActiveRecord::Migration def self.up create_table :posts do |t| t.string :title t.text :body t.timestamps end end def self.down drop_table :posts end end _ class AddUserIdToPost < ActiveRecord::Migration def self.up add_column :posts, :user_id, :string end def self.down remove_column :posts, :user_id end end

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  • Decode html tag so that it can be read when it goes back to the server more specifically the controller

    - by Yusuf
    My engine is Aspx. How can I decode/encode the html tags that is in my text box. I have the html tag to make it more readable. I tried the ValidationRequest and the htmlDecode(freqQuestion.Answer) but no luck. I just keep getting the same message. Server Error in '/Administrator' Application. A potentially dangerous Request.Form value was detected from the client (QuestionAnswer="...ics Phone:123-456-7890 Description: Request Validation has detected a potentially dangerous client input value, and processing of the request has been aborted. This value may indicate an attempt to compromise the security of your application, such as a cross-site scripting attack. To allow pages to override application request validation settings, set the requestValidationMode attribute in the httpRuntime configuration section to requestValidationMode="2.0". Example: . After setting this value, you can then disable request validation by setting validateRequest="false" in the Page directive or in the configuration section. However, it is strongly recommended that your application explicitly check all inputs in this case. For more information, see http://go.microsoft.com/fwlink/?LinkId=153133. View Page <%@ Page Title="" Language="C#" MasterPageFile="~/Views/Shared/Site.Master" validateRequest="false" Inherits="System.Web.Mvc.ViewPage<dynamic>" %> <asp:Content ID="Content1" ContentPlaceHolderID="TitleContent" runat="server"> EditFreqQuestionsUser </asp:Content> <asp:Content ID="Content2" ContentPlaceHolderID="MainContent" runat="server"> <script type="text/javascript"> $(document).ready(function () { $("#freqQuestionsUserUpdateButton").click(function () { $("#updateFreqQuestionsUser").submit(); }); }); </script> <h2>Edit Freq Questions User </h2> <%Administrator.DarkstarAdminProductionServices.FreqQuestionsUser freqQuestionsUser = ViewBag.freqQuestionsUser != null ? ViewBag.freqQuestionsUser : new Administrator.DarkstarAdminProductionServices.FreqQuestionsUser(); %> <%List<string> UserRoleList = Session["UserRoles"] != null ? (List<string>)Session["UserRoles"] : new List<string>(); %> <form id="updateFreqQuestionsUser" action="<%=Url.Action("SaveFreqQuestionsUser","Prod")%>" method="post"> <table> <tr> <td colspan="3" class="tableHeader">Freq Questions User Details <input type ="hidden" value="<%=freqQuestionsUser.freqQuestionsUserId%>" name="freqQuestionsUserId"/> </td> </tr> <tr> <td colspan="2" class="label">Question Description:</td> <td class="content"> <input type="text" maxlength="2000" name="QuestionDescription" value="<%=freqQuestionsUser.questionDescription%>" /> </td> </tr> <tr> <td colspan="2" class="label">QuestionAnswer:</td> <td class="content"> <input type="text" maxlength="2000" name="QuestionAnswer" value="<%=Server.HtmlDecode(freqQuestionsUser.questionAnswer)%>" /> </td> </tr> <tr> <td colspan="3" class="tableFooter"> <br /> <a id="freqQuestionsUserUpdateButton" href="#" class="regularButton">Save</a> <a href="javascript:history.back()" class="regularButton">Cancel</a> </td> </tr> </table> </form> </asp:Content> Controller [AuthorizeAttribute(AdminRoles = "EditFreqQuestionsUser")] public ActionResult SaveFreqQuestionsUser(string QuestionDescription, string QuestionAnswer) { Guid freqQuestionsUserId = Request.Form["freqQuestionsUserId"] != null ? new Guid(Request.Form["freqQuestionsUserId"]) : Guid.Empty; //load agreement eula ref AdminProductionServices.FreqQuestionsUser freqqQuestionsUser = Administrator.Models.AdminProduction.FreqQuestionsUser.LoadFreqQuestionsUser(freqQuestionsUserId, string.Empty, string.Empty)[0]; freqqQuestionsUser.questionDescription = QuestionDescription; freqqQuestionsUser.questionAnswer = QuestionAnswer; //save it Administrator.Models.AdminProduction.FreqQuestionsUser.addFreqQuestionsUser(freqqQuestionsUser); return RedirectToAction("SearchFreqQuestionsUser", "Prod", new { FreqQuestionsUserId = freqQuestionsUserId }); }

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  • NSStream sockets missing data

    - by Chris T.
    I am trying to pull some sample data from FreeDB as a proof of concept, but I am having a tough time retrieving all of the data off the incoming stream (I am only getting the last bits for the final query listed here (if handshakeCode = 3) I think this may be something with the threading on the main runloop, but I am not sure. Odd thing is when the buffer size is larger than 1-2 bytes (which works as expected), I seem to be losing access to the data programmatically (the totalOutput variable on the first set of data is incomplete). I set up a packet capture, and it looks like those 1024 bytes are coming across the wire, but the app just isn't working with it. It looks like the next event is coming through and basically taking over. I tried using an NSLock to no avail as well. If I drop the buffer size down to 1 or 2, things seem to be reading just fine. This is probably obvious to someone who does this all the time, but this is my first foray into this with something I am familiar with, technology wise in other languages / platforms. The following code will show you what is happening. Run with the buffer set to 1024, and you will see a short final string, but once you set it to 1, you will see the amount of data I was expecting (I was even expecting it to be split, so that's not a big worry) #import <Foundation/Foundation.h> #import <Cocoa/Cocoa.h> //STACK OVERFLOW CODE: @interface stackoverflow : NSObject <NSStreamDelegate> { NSInputStream *iStream; NSOutputStream *oStream; int handshakeCode; NSString *selectedDiscId; NSString *selectedGenre; } -(void)getMatchesFromFreeDB; -(void)sendToOutputStream:(NSString*)command; @end @implementation stackoverflow -(void)getMatchesFromFreeDB { NSHost *host = [NSHost hostWithName:@"freedb.freedb.org"]; [NSStream getStreamsToHost:host port:8880 inputStream:&iStream outputStream:&oStream]; [iStream retain]; [oStream retain]; [iStream setDelegate:self]; [oStream setDelegate:self]; [iStream scheduleInRunLoop:[NSRunLoop currentRunLoop] forMode:NSDefaultRunLoopMode]; [oStream scheduleInRunLoop:[NSRunLoop currentRunLoop] forMode:NSDefaultRunLoopMode]; [iStream open]; [oStream open]; handshakeCode = 0; //not done any processing } -(void)stream:(NSStream *)aStream handleEvent:(NSStreamEvent)eventCode { switch(eventCode) { case NSStreamEventOpenCompleted: { NSLog(@"Stream open completed"); break; } case NSStreamEventHasBytesAvailable: { NSLog(@"Stream has bytes available"); if (aStream == iStream) { NSMutableString *totalOutput = [NSMutableString stringWithString:@""]; //read data uint8_t buffer[1024]; int len; while ([iStream hasBytesAvailable]) { len = [iStream read:buffer maxLength:sizeof(buffer)]; if (len 0) { NSString *output = [[NSString alloc] initWithBytes:buffer length:len encoding:NSUTF8StringEncoding]; //this could have also been put into an NSData object if (nil != output) { //append to the total output [totalOutput appendString:output]; } } } NSLog(@"OUTPUT , %i:\n\n%@", [totalOutput lengthOfBytesUsingEncoding:NSUTF8StringEncoding], totalOutput); NSArray *outputComponents = [totalOutput componentsSeparatedByString:@" "]; //Attempt to get handshake code, since we haven't done it yet: if (handshakeCode == 1) { //we are just getting the sign-on banner: //let's move on: handshakeCode = 2; } else if (handshakeCode == 2) { handshakeCode = [[outputComponents objectAtIndex:0] intValue]; if (handshakeCode == 200) { NSLog(@"---Handshake OK %i", handshakeCode); NSMutableString *query = [NSMutableString stringWithString:@"cddb query f3114b11 17 225 19915 36489 54850 69425 87025 103948 123242 136075 152817 178335 192850 211677 235104 262090 284882 308658 4430\n"]; handshakeCode = 3; [self sendToOutputStream:query]; } } else if (handshakeCode == 3) { //now, we are reading out the matches: if ([[outputComponents objectAtIndex:0] intValue] == 200) //found exact match: { NSLog(@"Found exact match"); selectedGenre = [outputComponents objectAtIndex:1] ; selectedDiscId = [outputComponents objectAtIndex:2]; if (selectedGenre && selectedDiscId) { //send off the request to get the entry: NSString *query = [NSString stringWithFormat:@"cddb read %@ %@\n", selectedGenre, selectedDiscId]; [self sendToOutputStream:query]; handshakeCode = 4; } } } } break; } case NSStreamEventEndEncountered: { NSLog(@"Stream event end encountered"); break; } case NSStreamEventErrorOccurred: { NSLog(@"Stream error occurred"); break; } case NSStreamEventHasSpaceAvailable: { NSLog(@"Stream has space available"); if (aStream == oStream) { if (handshakeCode == 0) { handshakeCode = 1; [self sendToOutputStream:@"cddb hello stackoverflow localhost.localdomain test .01BETA\n"]; } } break; } } } -(void)sendToOutputStream:(NSString*)command { const uint8_t *rawCommand = (const uint8_t *)[command UTF8String]; [oStream write:rawCommand maxLength:strlen(rawCommand)]; NSLog(@"Sent command: %@",command); } @end int main (int argc, const char * argv[]) { NSAutoreleasePool * pool = [[NSAutoreleasePool alloc] init]; stackoverflow *test = [[stackoverflow alloc] init]; [test getMatchesFromFreeDB]; NSRunLoop *runLoop = [NSRunLoop currentRunLoop]; [runLoop run]; [pool drain]; return 0; } Any help is much appreciated! Thanks

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  • Rails multiple select box issue for search

    - by Reido
    First off here is my model, controller, view: My model, this is where I have my search code:--------------------------- def self.find_by_lcc(params) where = [] where << "category = 'Land'" unless params[:mls].blank? where << "mls = :mls" end unless params[:county].blank? where << "county = :county" end unless params[:acreage_range].blank? where << "acreage_range = :acreage_range" end unless params[:landtype].blank? where << "landtype = :landtype" end unless params[:price_range].blank? where << "price_range = :price_range" end if where.empty? [] else find(:all, :conditions => [where.join(" AND "), params], :order => "county, price desc") end end My controller:---------------- def land @counties = ['Adams', 'Alcorn', 'Amite', 'Attala'] @title = "Browse" return if params[:commit].nil? @properties = Property.find_by_lcc(params) else 'No properties were found' render :action = 'land_table' end My View: ---------------------- <table width="900"> <tr> <td> <% form_tag({ :action => "land" }, :method => "get") do %> <fieldset> <legend>Search our Land Properties</legend> <div class="form_row"><p>&nbsp;</p></div> <div class="form_row"> <label for="mls">MLS Number:</label>&nbsp; <%= text_field_tag 'mls', params[:mls] %> </div> <div class="form_row"> <label for "county"><font color="#ff0000">*County:</font></label>&nbsp; <%= select_tag "county", options_for_select(@counties), :multiple => true, :size => 6 %> </div> <div class="form_row"> <label for "acreage_range">Acreage:</label>&nbsp; <%= select_tag "acreage_range", options_for_select([['All',''],['1-10','1-10'],['11-25','11-25'],['26-50','26-50'],['51-100','51-100']]) %> </div> <div class="form_row"> <label for "landtype">Type:</label>&nbsp; <%= select_tag "landtype", options_for_select([['All',''],['Waterfront','Waterfront'],['Wooded','Wooded'],['Pasture','Pasture'],['Woods/Pasture','Woods/Pasture'],['Lot','Lot']]) %> </div> <div class="form_row"> <label for="price_range"><font color="#ff0000">*Price:</font></label>&nbsp; <%= select_tag "price_range", options_for_select([['All',''],['0-1,000','0-1,000'],['1,001-10,000','1,001-10,000'],['10,001-50,000','10,001-50,000'],['50,001-100,000','50,001-100,000'],['100,001-150,000']])%> </div> <input type="text" style="display: none;" disabled="disabled" size="1" /> <%= submit_tag "Search", :class => "submit" %> </fieldset> <% end%> </td> </tr> </table> The search works fine until I add ", :multiple = true, :size = 6" to make the county field multiple select. Then I get the error: Processing PublicController#land (for 65.0.81.83 at 2010-04-01 13:11:30) [GET] Parameters: {"acreage_range"=>"", "commit"=>"Search", "county"=>["Adams", "Amite"], "landtype"=>"", "price_range"=>"", "mls"=>""} ActiveRecord::StatementInvalid (Mysql::Error: Operand should contain 1 column(s): SELECT * FROM `properties` WHERE (category = 'Land' AND county = 'Adams','Amite') ORDER BY county, price desc): app/models/property.rb:93:in `find_by_lcc' app/controllers/public_controller.rb:84:in `land' /usr/lib/ruby/1.8/thread.rb:135:in `synchronize' fcgi (0.8.7) lib/fcgi.rb:117:in `session' fcgi (0.8.7) lib/fcgi.rb:104:in `each_request' fcgi (0.8.7) lib/fcgi.rb:36:in `each' dispatch.fcgi:24 I've tried to make the county, acreage_range, and price_range fields into multiple select boxes numerous ways, but can not get any method to work correctly. Any help would be greatly appreciated. Thanks,

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  • Matlab Image watermarking question , using both SVD and DWT

    - by Georgek
    Hello all . here is a code that i got over the net ,and it is supposed to embed a watermark of size(50*20) called _copyright.bmp in the Code below . the size of the cover object is (512*512), it is called _lena_std_bw.bmp.What we did here is we did DWT2 2 times for the image , when we reached our second dwt2 cA2 size is 128*128. You should notice that the blocksize and it equals 4, it is used to determine the max msg size based on cA2 according to the following code:max_message=RcA2*CcA2/(blocksize^2). in our current case max_message would equal 128*128/(4^2)=1024. i want to embed a bigger watermark in the 2nd dwt2 and lets say the size of that watermark is 400*10(i can change the dimension using MS PAINT), what i have to do is change the size of the blocksize to 2. so max_message=4096.Matlab gives me 3 errors and they are : ??? Error using == plus Matrix dimensions must agree. Error in == idwt2 at 93 x = upsconv2(a,{Lo_R,Lo_R},sx,dwtEXTM,shift)+ ... % Approximation. Error in == two_dwt_svd_low_low at 88 CAA1 = idwt2(cA22,cH2,cV2,cD2,'haar',[RcA1,CcA1]); The origional Code is (the origional code where blocksize =4): %This algorithm makes DWT for the whole image and after that make DWT for %cH1 and make SVD for cH2 and embed the watermark in every level after SVD %(1) -------------- Embed Watermark ------------------------------------ %Add the watermar W to original image I and give the watermarked image in J %-------------------------------------------------------------------------- % set the gain factor for embeding and threshold for evaluation clc; clear all; close all; % save start time start_time=cputime; % set the value of threshold and alpha thresh=.5; alpha =0.01; % read in the cover object file_name='_lena_std_bw.bmp'; cover_object=double(imread(file_name)); % determine size of watermarked image Mc=size(cover_object,1); %Height Nc=size(cover_object,2); %Width % read in the message image and reshape it into a vector file_name='_copyright.bmp'; message=double(imread(file_name)); T=message; Mm=size(message,1); %Height Nm=size(message,2); %Width % perform 1-level DWT for the whole cover image [cA1,cH1,cV1,cD1] = dwt2(cover_object,'haar'); % determine the size of cA1 [RcA1 CcA1]=size(cA1) % perform 2-level DWT for cA1 [cA2,cH2,cV2,cD2] = dwt2(cA1,'haar'); % determine the size of cA2 [RcA2 CcA2]=size(cA2) % set the value of blocksize blocksize=4 % reshape the watermark to a vector message_vector=round(reshape(message,Mm*Nm,1)./256); W=message_vector; % determine maximum message size based on cA2, and blocksize max_message=RcA2*CcA2/(blocksize^2) % check that the message isn't too large for cover if (length(message) max_message) error('Message too large to fit in Cover Object') end %----------------------- process the image in blocks ---------------------- x=1; y=1; for (kk = 1:length(message_vector)) [cA2u cA2s cA2v]=svd(cA2(y:y+blocksize-1,x:x+blocksize-1)); % if message bit contains zero, modify S of the original image if (message_vector(kk) == 0) cA2s = cA2s*(1 + alpha); % otherwise mask is filled with zeros else cA2s=cA2s; end cA22(y:y+blocksize-1,x:x+blocksize-1)=cA2u*cA2s*cA2v; % move to next block of mask along x; If at end of row, move to next row if (x+blocksize) >= CcA2 x=1; y=y+blocksize; else x=x+blocksize; end end % perform IDWT CAA1 = idwt2(cA22,cH2,cV2,cD2,'haar',[RcA1,CcA1]); watermarked_image= idwt2(CAA1,cH1,cV1,cD1,'haar',[Mc,Nc]); % convert back to uint8 watermarked_image_uint8=uint8(watermarked_image); % write watermarked Image to file imwrite(watermarked_image_uint8,'dwt_watermarked.bmp','bmp'); % display watermarked image figure(1) imshow(watermarked_image_uint8,[]) title('Watermarked Image') %(2) ---------------------------------------------------------------------- %---------- Extract Watermark from attacked watermarked image ------------- %-------------------------------------------------------------------------- % read in the watermarked object file_name='dwt_watermarked.bmp'; watermarked_image=double(imread(file_name)); % determine size of watermarked image Mw=size(watermarked_image,1); %Height Nw=size(watermarked_image,2); %Width % perform 1-level DWT for the whole watermarked image [ca1,ch1,cv1,cd1] = dwt2(watermarked_image,'haar'); % determine the size of ca1 [Rca1 Cca1]=size(ca1); % perform 2-level DWT for ca1 [ca2,ch2,cv2,cd2] = dwt2(ca1,'haar'); % determine the size of ca2 [Rca2 Cca2]=size(ca2); % process the image in blocks % for each block get a bit for message x=1; y=1; for (kk = 1:length(message_vector)) % sets correlation to 1 when patterns are identical to avoid /0 errors % otherwise calcluate difference between the cover image and the % watermarked image [cA2u cA2s cA2v]=svd(cA2(y:y+blocksize-1,x:x+blocksize-1)); [ca2u1 ca2s1 ca2v1]=svd(ca2(y:y+blocksize-1,x:x+blocksize-1)); correlation(kk)=diag(ca2s1-cA2s)'*diag(ca2s1-cA2s)/(alpha*alpha)/(diag(cA2s)*diag(cA2s)); % move on to next block. At and of row move to next row if (x+blocksize) >= Cca2 x=1; y=y+blocksize; else x=x+blocksize; end end % if correlation exceeds average correlation correlation(kk)=correlation(kk)+mean(correlation(1:Mm*Nm)); for kk = 1:length(correlation) if (correlation(kk) > thresh*alpha);%thresh*mean(correlation(1:Mo*No))) message_vector(kk)=0; end end % reshape the message vector and display recovered watermark. figure(2) message=reshape(message_vector(1:Mm*Nm),Mm,Nm); imshow(message,[]) title('Recovered Watermark') % display processing time elapsed_time=cputime-start_time, please do help,its my graduation project and i have been trying this code for along time but failed miserable. Thanks in advance

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  • Fragment shaders on a texture

    - by Snowangelic
    Hello stack overflow. I am trying to add some post-processing capabilities to a program. The rendering is done using openGL. I just want to allow the program to load some home made fragment shader and use them on the video stream. I wrote a little piece of shader using "OpenGL Shader Builder" that just turns a texture in grayscale. The shaders works well in the shader builder but I can't make it work in the main program. The screens stays all black. Here is the setup : @implementation PluginGLView - (id) initWithCoder: (NSCoder *) coder { const GLubyte * strExt; if ((self = [super initWithCoder:coder]) == nil) return nil; glLock = [[NSLock alloc] init]; if (nil == glLock) { [self release]; return nil; } // Init pixel format attribs NSOpenGLPixelFormatAttribute attrs[] = { NSOpenGLPFAAccelerated, NSOpenGLPFANoRecovery, NSOpenGLPFADoubleBuffer, 0 }; // Get pixel format from OpenGL NSOpenGLPixelFormat* pixFmt = [[NSOpenGLPixelFormat alloc] initWithAttributes:attrs]; if (!pixFmt) { NSLog(@"No Accelerated OpenGL pixel format found\n"); NSOpenGLPixelFormatAttribute attrs2[] = { NSOpenGLPFANoRecovery, 0 }; // Get pixel format from OpenGL pixFmt = [[NSOpenGLPixelFormat alloc] initWithAttributes:attrs2]; if (!pixFmt) { NSLog(@"No OpenGL pixel format found!\n"); [self release]; return nil; } } [self setPixelFormat:[pixFmt autorelease]]; /* long swapInterval = 1 ; [[self openGLContext] setValues:&swapInterval forParameter:NSOpenGLCPSwapInterval]; */ [glLock lock]; [[self openGLContext] makeCurrentContext]; // Init object members strExt = glGetString (GL_EXTENSIONS); texture_range = gluCheckExtension ((const unsigned char *)"GL_APPLE_texture_range", strExt) ? GL_TRUE : GL_FALSE; texture_hint = GL_STORAGE_SHARED_APPLE ; client_storage = gluCheckExtension ((const unsigned char *)"GL_APPLE_client_storage", strExt) ? GL_TRUE : GL_FALSE; rect_texture = gluCheckExtension((const unsigned char *)"GL_EXT_texture_rectangle", strExt) ? GL_TRUE : GL_FALSE; // Setup some basic OpenGL stuff glPixelStorei(GL_UNPACK_ALIGNMENT, 1); glTexEnvi(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_REPLACE); glColor4f(1.0f, 1.0f, 1.0f, 1.0f); glClearColor(0.0f, 0.0f, 0.0f, 1.0f); glClear(GL_COLOR_BUFFER_BIT); // Loads the shaders shader=LoadShader(GL_FRAGMENT_SHADER,"/Users/alexandremathieu/fragment.fs"); program=glCreateProgram(); glAttachShader(program, shader); glLinkProgram(program); glUseProgram(program); [NSOpenGLContext clearCurrentContext]; [glLock unlock]; image_width = 1024; image_height = 512; image_depth = 16; image_type = GL_UNSIGNED_SHORT_1_5_5_5_REV; image_base = (GLubyte *) calloc(((IMAGE_COUNT * image_width * image_height) / 3) * 4, image_depth >> 3); if (image_base == nil) { [self release]; return nil; } // Create and load textures for the first time [self loadTextures:GL_TRUE]; // Init fps timer //gettimeofday(&cycle_time, NULL); drawBG = YES; // Call for a redisplay noDisplay = YES; PSXDisplay.Disabled = 1; [self setNeedsDisplay:true]; return self; } And here is the "render screen" function wich basically...renders the screen. - (void)renderScreen { int bufferIndex = whichImage; glBindTexture(GL_TEXTURE_RECTANGLE_EXT, bufferIndex+1); glUseProgram(program); int loc=glGetUniformLocation(program, "texture"); glUniform1i(loc,bufferIndex+1); glTexSubImage2D(GL_TEXTURE_RECTANGLE_EXT, 0, 0, 0, image_width, image_height, GL_BGRA, image_type, image[bufferIndex]); glBegin(GL_QUADS); glTexCoord2f(0.0f, 0.0f); glVertex2f(-1.0f, 1.0f); glTexCoord2f(0.0f, image_height); glVertex2f(-1.0f, -1.0f); glTexCoord2f(image_width, image_height); glVertex2f(1.0f, -1.0f); glTexCoord2f(image_width, 0.0f); glVertex2f(1.0f, 1.0f); glEnd(); [[self openGLContext] flushBuffer]; [NSOpenGLContext clearCurrentContext]; //[glLock unlock]; } and finally here's the shader. uniform sampler2DRect texture; void main() { vec4 color, texel; color = gl_Color; texel = texture2DRect(texture, gl_TexCoord[0].xy); color *= texel; // Begin Shader float gray=0.0; gray+=(color.r + color.g + color.b)/3.0; color=vec4(gray,gray,gray,color.a); // End Shader gl_FragColor = color; } The loading and using of shaders works since I am able to turn the screen all red with this shader void main(){ gl_FragColor=vec4(1.0,0.0,0.0,1.0); } If the shader contains a syntax error I get an error message from the LoadShader function etc. If I remove the use of the shader, everything works normally. I think the problem comes from the "passing the texture as a uniform parameter" thing. But these are my very firsts step with openGL and I cant be sure of anything. Don't hesitate to ask for more info. Thank you Stack O.

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  • collision with moving objects

    - by blacksheep
    tried to write a collision with the moving "floats" but did not succeed. maybe wrong place of the "collision" code? thanx 4 help! // // FruitsView.m // import "FruitsView.h" import "Constants.h" import "Utilities.h" define kFloat1Speed 0.15 define kFloat2Speed 0.3 define kFloat3Speed 0.2 @interface FruitsView (Private) - (void) stopTimer; @end @implementation FruitsView @synthesize apple, float1, float2, float3, posFloat1, posFloat2, posFloat3; -(void)onTimer { float1.center = CGPointMake(float1.center.x+posFloat1.x,float1.cen ter.y+posFloat1.y); if(float1.center.x 380 || float1.center.x < -60) posFloat1.x = -posFloat1.x; if(float1.center.y 100 || float1.center.y < -40) posFloat1.y = -posFloat1.y; float2.center = CGPointMake(float2.center.x+posFloat2.x,float2.cen ter.y+posFloat2.y); if(float2.center.x 380 || float2.center.x < -50) posFloat2.x = -posFloat2.x; if(float2.center.y 150 || float2.center.y < -30) posFloat2.y = -posFloat2.y; float3.center = CGPointMake(float3.center.x+posFloat3.x,float3.cen ter.y+posFloat3.y); if(float3.center.x 380 || float3.center.x < -70) posFloat3.x = -posFloat3.x; if(float3.center.y 100 || float3.center.y < -20) posFloat3.y = -posFloat3.y; if(CGRectIntersectsRect(apple.frame,float1.frame)) { if(apple.center.y float1.center.y) { posApple.y = -posApple.y; } } if(CGRectIntersectsRect(apple.frame,float2.frame)) { if(apple.center.y float2.center.y) { posFloat2.y = -posFloat2.y; } } if(CGRectIntersectsRect(apple.frame,float3.frame)) { if(apple.center.y float3.center.y) { posFloat3.y = -posFloat3.y; } } } pragma mark Initialisation/destruction (void)awakeFromNib { [NSTimer scheduledTimerWithTimeInterval:0.0001 target:self selector:@selector(onTimer) userInfo:nil repeats:YES]; posFloat1 = CGPointMake(kFloat1Speed, 0); posFloat2 = CGPointMake(kFloat2Speed, 0); posFloat3 = CGPointMake(kFloat3Speed, 0); timer = nil; modeLock = lockNotYetChosen; defaultSize = self.bounds.size.width; modal = self.tag; [[UIAccelerometer sharedAccelerometer] setDelegate:self]; [UIView beginAnimations:nil context:nil]; [UIView setAnimationRepeatCount:1]; eadbea.transform = CGAffineTransformMakeScale(0.5,0.5); [UIView commitAnimations]; [UIView beginAnimations:nil context:nil]; [UIView setAnimationRepeatCount:1]; apple.transform = CGAffineTransformMakeScale(0.5,0.5); [UIView commitAnimations]; } pragma mark Background animation processing (void) startTimer { if (!timer) { timer = [[NSTimer scheduledTimerWithTimeInterval:1.0/60.0 target:self selector:@selector(timerTick:) userInfo:nil repeats:YES] retain]; } } (void) stopTimer { [timer invalidate]; [timer release]; timer = nil; } (void) check:(CGPoint*)position delta:(CGSize*)delta halfSize:(CGSize)halfSize forBouncingAgainst:(CGSize)containerSize { if ((position-x - halfSize.width)<0) { delta-width = fabsf(delta-width)*BOUNCE_DAMPING; position-x = halfSize.width; } if ((position-x + halfSize.width)containerSize.width) { delta-width = fabsf(delta-width)*-BOUNCE_DAMPING; position-x = containerSize.width - halfSize.width; } if ((position-y - halfSize.height)<0) { delta-height = fabsf(delta-height)*BOUNCE_DAMPING; position-y = halfSize.height; } if ((position-y + halfSize.height)containerSize.height) { delta-height = fabsf(delta-height)*-BOUNCE_DAMPING; position-y = containerSize.height - halfSize.height; } } (void) timerTick: (NSTimer*)timer { dragDelta = CGSizeScale(dragDelta, INERTIAL_DAMPING); if ((fabsf(dragDelta.width)DELTA_ZERO_THRESHOLD) || (fabsf(dragDelta.height)DELTA_ZERO_THRESHOLD)) { CGPoint ctr = CGPointApplyDelta(self.center, dragDelta); CGSize halfSize = CGSizeMake(self.bounds.size.width/4, self.bounds.size.height/4); [self check:&ctr delta:&dragDelta halfSize:halfSize forBouncingAgainst:self.superview.bounds.size]; self.center = ctr; } else { [self stopTimer]; } } pragma mark Input Handling (void)touchesMoved:(NSSet *)touches withEvent:(UIEvent )event { NSSet allTouches = [event touchesForView:self]; if ([allTouches count]==1) { if (modeLocklockNotYetChosen) return; UITouch* anyTouch = [touches anyObject]; lastMove = anyTouch.timestamp; CGPoint now = [anyTouch locationInView: self.superview]; CGPoint then = [anyTouch previousLocationInView: self.superview]; dragDelta = CGPointDelta(now, then); self.center = CGPointApplyDelta(self.center, dragDelta); [self stopTimer]; } } (void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event { NSSet* allTouches = [event touchesForView:self]; if ([touches count]==[allTouches count]) { modeLock = lockNotYetChosen; if ((event.timestamp - lastMove) MOVEMENT_PAUSE_THRESHOLD) return; if ((fabsf(dragDelta.width)INERTIA_THRESHOLD) || (fabsf(dragDelta.height)INERTIA_THRESHOLD)) { [self startTimer]; } } } (void)touchesCancelled:(NSSet *)touches withEvent:(UIEvent *)event { modeLock = lockNotYetChosen; [self stopTimer]; } (void)dealloc { [float1 release]; [float2 release]; [float3 release]; [apple release]; [bear_head release]; [self stopTimer]; [super dealloc]; } @end

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  • How to use EJB 3.1 DI in Servlet ? (Could not inject session bean by @EJB from web application)

    - by kislo_metal
    I am tying to merging web application(gwt, jpa) to an separate 2 application(business login in ejb/jpa and web client in gwt). Currently i can`t inject my beans from web application (simple servlet) I am using glassfish v3. module limbo(ejb jar) is in dependency of module lust (war). If I use lust with compiler output of limbo everything work perfect (if ejb in web application and the are deploying together as one application). Have I messed some container configuration ? Here is my steps: I have some limbo.jar (ejb-jar) deployed to ejb container. I do not use any ejb-jar.xml, only annotations. package ua.co.inferno.limbo.persistence.beans; import javax.ejb.Remote; @Remote public interface IPersistentServiceRemote { ArrayList<String> getTerminalACPList(); ArrayList<String> getBoxACPList(); ArrayList<String> getCNPList(); ArrayList<String> getCNSList(); String getProductNamebyID(int boxid); ArrayList<String> getRegionsList(String lang); long getSequence(); void persistEntity (Object ent); } package ua.co.inferno.limbo.persistence.beans; import ua.co.inferno.limbo.persistence.entitis.EsetChSchemaEntity; import ua.co.inferno.limbo.persistence.entitis.EsetKeyActionsEntity; @Local public interface IPersistentService { ArrayList<String> getTerminalACPList(); ArrayList<String> getBoxACPList(); ArrayList<String> getCNPList(); ArrayList<String> getCNSList(); String getProductNamebyID(int boxid); ArrayList<String> getRegionsList(String lang); long getSequence(); long persistPurchaseBox(EsetRegPurchaserEntity rp); void removePurchaseTempBox(EsetRegPurchaserTempEntity rpt); EsetRegionsEntity getRegionsById(long rid); void persistEntity (Object ent); } package ua.co.inferno.limbo.persistence.beans; import ua.co.inferno.limbo.persistence.entitis.EsetChSchemaEntity; import ua.co.inferno.limbo.persistence.entitis.EsetKeyActionsEntity; import ua.co.inferno.limbo.persistence.entitis.EsetRegBoxesEntity; import javax.ejb.Stateless; import javax.persistence.EntityManager; import javax.persistence.PersistenceContext; @Stateless(name = "PersistentService") public class PersistentServiceEJB implements IPersistentService, IPersistentServiceRemote{ @PersistenceContext(unitName = "Limbo") EntityManager em; public PersistentServiceEJB() { } ......... } Than i trying to use PersistentService session bean(included in limbo.jar) from web application in lust.war (the limbo.jar & lust.war is not in ear) package ua.co.lust; import ua.co.inferno.limbo.persistence.beans.IPersistentService; import javax.ejb.EJB; import javax.servlet.ServletException; import javax.servlet.annotation.WebServlet; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import java.io.IOException; @WebServlet(name = "ServletTest", urlPatterns = {"/"}) public class ServletTest extends HttpServlet { protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { service(request, response); } protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { service(request, response); } @EJB private IPersistentService pService; public void service(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { String hi = pService.getCNPList().toString(); System.out.println("testBean.hello method returned: " + hi); System.out.println("In MyServlet::init()"); System.out.println("all regions" + pService.getRegionsList("ua")); System.out.println("all regions" + pService.getBoxACPList()); } } web.xm <?xml version="1.0" encoding="UTF-8"?> <web-app xmlns="http://java.sun.com/xml/ns/javaee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd" version="3.0"> <servlet> <servlet-name>ServletTest</servlet-name> <servlet-class>ua.co.lust.ServletTest</servlet-class> </servlet> </web-app> When servelt is loading i ge 404 eror (The requested resource () is not available.) And errors in logs : global Log Level SEVERE Logger global Name-Value Pairs {_ThreadName=Thread-1, _ThreadID=31} Record Number 1421 Message ID Complete Message Class [ Lua/co/inferno/limbo/persistence/beans/IPersistentService; ] not found. Error while loading [ class ua.co.lust.ServletTest ] javax.enterprise.system.tools.deployment.org.glassfish.deployment.common Log Level WARNING Logger javax.enterprise.system.tools.deployment.org.glassfish.deployment.common Name-Value Pairs {_ThreadName=Thread-1, _ThreadID=31} Record Number 1422 Message ID Error in annotation processing Complete Message java.lang.NoClassDefFoundError: Lua/co/inferno/limbo/persistence/beans/IPersistentService; ejb jar was deployed with this info log : Log Level INFO Logger javax.enterprise.system.container.ejb.com.sun.ejb.containers Name-Value Pairs {_ThreadName=Thread-1, _ThreadID=26} Record Number 1436 Message ID Glassfish-specific (Non-portable) JNDI names for EJB PersistentService Complete Message [ua.co.inferno.limbo.persistence.beans.IPersistentServiceRemote#ua.co.inferno.limbo.persistence.beans.IPersistentServiceRemote, ua.co.inferno.limbo.persistence.beans.IPersistentServiceRemote] Log Level INFO Logger javax.enterprise.system.tools.admin.org.glassfish.deployment.admin Name-Value Pairs {_ThreadName=Thread-1, _ThreadID=26} Record Number 1445 Message ID Complete Message limbo was successfully deployed in 610 milliseconds. Do i nee to add some additional configuration in a case of injections from others application? Some ideas?

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  • Lazy loading of child throwing session error

    - by Thomas Buckley
    I'm the following error when calling purchaseService.updatePurchase(purchase) inside my TagController: SEVERE: Servlet.service() for servlet [PurchaseAPIServer] in context with path [/PurchaseAPIServer] threw exception [Request processing failed; nested exception is org.hibernate.LazyInitializationException: failed to lazily initialize a collection of role: com.app.model.Purchase.tags, no session or session was closed] with root cause org.hibernate.LazyInitializationException: failed to lazily initialize a collection of role: com.app.model.Purchase.tags, no session or session was closed at org.hibernate.collection.AbstractPersistentCollection.throwLazyInitializationException(AbstractPersistentCollection.java:383) at org.hibernate.collection.AbstractPersistentCollection.throwLazyInitializationExceptionIfNotConnected(AbstractPersistentCollection.java:375) at org.hibernate.collection.AbstractPersistentCollection.initialize(AbstractPersistentCollection.java:368) at org.hibernate.collection.PersistentSet.add(PersistentSet.java:212) at com.app.model.Purchase.addTags(Purchase.java:207) at com.app.controller.TagController.createAll(TagController.java:79) 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 org.springframework.web.method.support.InvocableHandlerMethod.invoke(InvocableHandlerMethod.java:212) at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:126) at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:96) at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:617) at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:578) at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:80) at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:900) at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:827) at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:882) at org.springframework.web.servlet.FrameworkServlet.doPost(FrameworkServlet.java:789) at javax.servlet.http.HttpServlet.service(HttpServlet.java:641) at javax.servlet.http.HttpServlet.service(HttpServlet.java:722) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:305) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210) at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:225) at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:169) at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:472) at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:168) at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:98) at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:927) at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:118) at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:407) at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:999) at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:565) at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:309) at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886) at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908) at java.lang.Thread.run(Thread.java:662) TagController: @RequestMapping(value = "purchases/{purchaseId}/tags", method = RequestMethod.POST, params = "manyTags") @ResponseStatus(HttpStatus.CREATED) public void createAll(@PathVariable("purchaseId") final Long purchaseId, @RequestBody final Tag[] entities) { Purchase purchase = purchaseService.getById(purchaseId); Set<Tag> tags = new HashSet<Tag>(Arrays.asList(entities)); purchase.addTags(tags); purchaseService.updatePurchase(purchase); } Purchase: @Entity @XmlRootElement public class Purchase implements Serializable { /** * */ private static final long serialVersionUID = 6603477834338392140L; @Id @GeneratedValue(strategy = GenerationType.AUTO) private Long id; @OneToMany(mappedBy = "purchase", fetch = FetchType.LAZY, cascade={CascadeType.ALL}) private Set<Tag> tags; @JsonIgnore public Set<Tag> getTags() { if (tags == null) { tags = new LinkedHashSet<Tag>(); } return tags; } public void setTags(Set<Tag> tags) { this.tags = tags; } ... } Tag: @Entity @XmlRootElement public class Tag implements Serializable { /** * */ private static final long serialVersionUID = 5165922776051697002L; @Id @GeneratedValue(strategy = GenerationType.AUTO) private Long id; @ManyToOne(fetch = FetchType.LAZY) @JoinColumns({@JoinColumn(name = "PURCHASEID", referencedColumnName = "ID")}) private Purchase purchase; @JsonIgnore public Purchase getPurchase() { return purchase; } public void setPurchase(Purchase purchase) { this.purchase = purchase; } } PurchaseService: @Service public class PurchaseService implements IPurchaseService { @Autowired private IPurchaseDAO purchaseDAO; public PurchaseService() { } @Transactional public List<Purchase> getAll() { return purchaseDAO.findAll(); } @Transactional public Purchase getById(Long id) { return purchaseDAO.findOne(id); } @Transactional public void addPurchase(Purchase purchase) { purchaseDAO.save(purchase); } @Transactional public void updatePurchase(Purchase purchase) { purchaseDAO.update(purchase); } } TagService: @Service public class TagService implements ITagService { @Autowired private ITagDAO tagDAO; public TagService() { } @Transactional public List<Tag> getAll() { return tagDAO.findAll(); } @Transactional public Tag getById(Long id) { return tagDAO.findOne(id); } @Transactional public void addTag(Tag tag) { tagDAO.save(tag); } @Transactional public void updateTag(Tag tag) { tagDAO.update(tag); } } Any ideas on how I can fix this? (I want to avoid using EAGER loading). Do I need to setup some form of session management for transactions? Thanks

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  • What is stopping data flow with .NET 3.5 asynchronous System.Net.Sockets.Socket?

    - by TonyG
    I have a .NET 3.5 client/server socket interface using the asynchronous methods. The client connects to the server and the connection should remain open until the app terminates. The protocol consists of the following pattern: send stx receive ack send data1 receive ack send data2 (repeat 5-6 while more data) receive ack send etx So a single transaction with two datablocks as above would consist of 4 sends from the client. After sending etx the client simply waits for more data to send out, then begins the next transmission with stx. I do not want to break the connection between individual exchanges or after each stx/data/etx payload. Right now, after connection, the client can send the first stx, and get a single ack, but I can't put more data onto the wire after that. Neither side disconnects, the socket is still intact. The client code is seriously abbreviated as follows - I'm following the pattern commonly available in online code samples. private void SendReceive(string data) { // ... SocketAsyncEventArgs completeArgs; completeArgs.Completed += new EventHandler<SocketAsyncEventArgs>(OnSend); clientSocket.SendAsync(completeArgs); // two AutoResetEvents, one for send, one for receive if ( !AutoResetEvent.WaitAll(autoSendReceiveEvents , -1) ) Log("failed"); else Log("success"); // ... } private void OnSend( object sender , SocketAsyncEventArgs e ) { // ... Socket s = e.UserToken as Socket; byte[] receiveBuffer = new byte[ 4096 ]; e.SetBuffer(receiveBuffer , 0 , receiveBuffer.Length); e.Completed += new EventHandler<SocketAsyncEventArgs>(OnReceive); s.ReceiveAsync(e); // ... } private void OnReceive( object sender , SocketAsyncEventArgs e ) {} // ... if ( e.BytesTransferred > 0 ) { Int32 bytesTransferred = e.BytesTransferred; String received = Encoding.ASCII.GetString(e.Buffer , e.Offset , bytesTransferred); dataReceived += received; } autoSendReceiveEvents[ SendOperation ].Set(); // could be moved elsewhere autoSendReceiveEvents[ ReceiveOperation ].Set(); // releases mutexes } The code on the server is very similar except that it receives first and then sends a response - the server is not doing anything (that I can tell) to modify the connection after it sends a response. The problem is that the second time I hit SendReceive in the client, the connection is already in a weird state. Do I need to do something in the client to preserve the SocketAsyncEventArgs, and re-use the same object for the lifetime of the socket/connection? I'm not sure which eventargs object should hang around during the life of the connection or a given exchange. Do I need to do something, or Not do something in the server to ensure it continues to Receive data? The server setup and response processing looks like this: void Start() { // ... listenSocket.Bind(...); listenSocket.Listen(0); StartAccept(null); // note accept as soon as we start. OK? mutex.WaitOne(); } void StartAccept(SocketAsyncEventArgs acceptEventArg) { if ( acceptEventArg == null ) { acceptEventArg = new SocketAsyncEventArgs(); acceptEventArg.Completed += new EventHandler<SocketAsyncEventArgs>(OnAcceptCompleted); } Boolean willRaiseEvent = this.listenSocket.AcceptAsync(acceptEventArg); if ( !willRaiseEvent ) ProcessAccept(acceptEventArg); // ... } private void OnAcceptCompleted( object sender , SocketAsyncEventArgs e ) { ProcessAccept(e); } private void ProcessAccept( SocketAsyncEventArgs e ) { // ... SocketAsyncEventArgs readEventArgs = new SocketAsyncEventArgs(); readEventArgs.SetBuffer(dataBuffer , 0 , Int16.MaxValue); readEventArgs.Completed += new EventHandler<SocketAsyncEventArgs>(OnIOCompleted); readEventArgs.UserToken = e.AcceptSocket; dataReceived = ""; // note server is degraded for single client/thread use // As soon as the client is connected, post a receive to the connection. Boolean willRaiseEvent = e.AcceptSocket.ReceiveAsync(readEventArgs); if ( !willRaiseEvent ) this.ProcessReceive(readEventArgs); // Accept the next connection request. this.StartAccept(e); } private void OnIOCompleted( object sender , SocketAsyncEventArgs e ) { // switch ( e.LastOperation ) case SocketAsyncOperation.Receive: ProcessReceive(e); // similar to client code // operate on dataReceived here case SocketAsyncOperation.Send: ProcessSend(e); // similar to client code } // execute this when a data has been processed into a response (ack, etc) private SendResponseToClient(string response) { // create buffer with response // currentEventArgs has class scope and is re-used currentEventArgs.SetBuffer(sendBuffer , 0 , sendBuffer.Length); Boolean willRaiseEvent = currentClient.SendAsync(currentEventArgs); if ( !willRaiseEvent ) ProcessSend(currentEventArgs); } A .NET trace shows the following when sending ABC\r\n: Socket#7588182::SendAsync() Socket#7588182::SendAsync(True#1) Data from Socket#7588182::FinishOperation(SendAsync) 00000000 : 41 42 43 0D 0A Socket#7588182::ReceiveAsync() Exiting Socket#7588182::ReceiveAsync() - True#1 And it stops there. It looks just like the first send from the client but the server shows no activity. I think that could be info overload for now but I'll be happy to provide more details as required. Thanks!

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  • java.lang.ArrayIndexOutOfBoundsException

    - by thefonso
    Here is the code. import java.applet.Applet; import java.awt.Button; import java.awt.Color; import java.awt.Graphics; import java.awt.event.ActionEvent; import java.awt.event.ActionListener; public class GuessingGame extends Applet{ /** * */ private static final long serialVersionUID = 1L; private final int START_X = 20; private final int START_Y = 40; private final int ROWS = 4; private final int COLS = 4; private final int BOX_WIDTH = 20; private final int BOX_HEIGHT = 20; //this is used to keep track of boxes that have been matched. private boolean matchedBoxes[][]; //this is used to keep track of two boxes that have been clicked. private MaskableBox chosenBoxes[]; private MaskableBox boxes[][]; private Color boxColors[][]; private Button resetButton; public void init() { boxes = new MaskableBox[ROWS][COLS]; boxColors = new Color[ROWS][COLS]; resetButton = new Button("Reset Colors"); resetButton.addActionListener(new ActionListener() { public void actionPerformed(ActionEvent e) { randomizeColors(); buildBoxes(); repaint(); } }); add(resetButton); //separate building colors so we can add a button later //to re-randomize them. randomizeColors(); buildBoxes(); } public void paint(Graphics g) { for (int row =0; row < boxes.length; row ++) { for (int col = 0; col < boxes[row].length; col++) { if(boxes[row][col].isClicked()) { //boxes[row][col].setMaskColor(Color.black); //boxes[row][col].setMask(!boxes[row][col].isMask()); //boxes[row][col].setClicked(false); //} if (!matchedBoxes[row][col]) { gameLogic(boxes[row][col]); //boxes[row][col].draw(g); } } } } //loop through the boxes and draw them. for (int row = 0; row < boxes.length; row++) { for (int col = 0; col < boxes[row].length; col++) { boxes[row][col].draw(g); } } } public void gameLogic(MaskableBox box) { if ((chosenBoxes[0] != null)&&(chosenBoxes[1] != null)) { if(chosenBoxes[0].getBackColor() == chosenBoxes[1].getBackColor()) { for (int i=0; 0 <= chosenBoxes.length; ++i ) { for(int row = 0; row < boxes.length; row++) { for(int col = 0; col < boxes[row].length; col++) { if( boxes[row][col] == chosenBoxes[i] ) { System.out.println("boxes [row][col] == chosenBoxes[] at index: " + i ); matchedBoxes[row][col] = true; break; } } } } }else { chosenBoxes[0].setMask(true); chosenBoxes[1].setMask(true); } chosenBoxes = new MaskableBox[2]; }else { if (chosenBoxes[0] == null) { chosenBoxes[0] = box; chosenBoxes[0].setMask(false); return; }else{ if (chosenBoxes[1] == null) { chosenBoxes[1] = box; chosenBoxes[1].setMask(false); } } } } private void removeMouseListeners() { for(int row = 0; row < boxes.length; row ++) { for(int col = 0; col < boxes[row].length; col++) { removeMouseListener(boxes[row][col]); } } } private void buildBoxes() { // need to clear any chosen boxes when building new array. chosenBoxes = new MaskableBox[2]; // create a new matchedBoxes array matchedBoxes = new boolean [ROWS][COLS]; removeMouseListeners(); for(int row = 0; row < boxes.length; row++) { for(int col = 0; col < boxes[row].length; col++) { boxes[row][col] = new MaskableBox(START_X + col * BOX_WIDTH, START_Y + row * BOX_HEIGHT, BOX_WIDTH, BOX_HEIGHT, Color.gray, boxColors[row][col], true, true, this); addMouseListener(boxes[row][col]); } } } private void randomizeColors() { int[] chosenColors = {0,0,0,0,0,0,0,0}; Color[] availableColors = {Color.red, Color.blue, Color.green, Color.yellow, Color.cyan, Color.magenta, Color.pink, Color.orange }; for(int row = 0; row < boxes.length; row++) { for (int col = 0; col < boxes[row].length; col++) { for (;;) { int rnd = (int) (Math.random() * 8); if (chosenColors[rnd]< 2) { chosenColors[rnd]++; boxColors[row][col] = availableColors[rnd]; break; } } } } } } here is the second batch of code containing maskablebox import java.awt.Color; import java.awt.Container; import java.awt.Graphics; public class MaskableBox extends ClickableBox { private boolean mask; private Color maskColor; Container parent; public MaskableBox(int x, int y, int width, int height, Color borderColor, Color backColor, boolean drawBorder, boolean mask, Container parent ) { super(x, y, width, height, borderColor, backColor, drawBorder, parent); this.parent = parent; this.mask = mask; } public void draw(Graphics g) { if(mask=false) { super.draw(g); // setOldColor(g.getColor()); // g.setColor(maskColor); // g.fillRect(getX(),getY(),getWidth(), getHeight()); // if(isDrawBorder()) { // g.setColor(getBorderColor()); // g.drawRect(getX(),getY(),getWidth(),getHeight()); // } // g.setColor(getOldColor()); }else { if(mask=true) { //super.draw(g); setOldColor(g.getColor()); g.setColor(maskColor); g.fillRect(getX(),getY(),getWidth(), getHeight()); if(isDrawBorder()) { g.setColor(getBorderColor()); g.drawRect(getX(),getY(),getWidth(),getHeight()); } g.setColor(getOldColor()); } } } public boolean isMask() { return mask; } public void setMask(boolean mask) { this.mask = mask; } public Color getMaskColor() { return maskColor; } public void setMaskColor(Color maskColor) { this.maskColor = maskColor; } } I keep getting these error messages. I'm going nuts trying to figure this out. can anyone tell me what I'm doing wrong? boxes [row][col] == chosenBoxes[] at index: 0 boxes [row][col] == chosenBoxes[] at index: 1 Exception in thread "AWT-EventQueue-1" java.lang.ArrayIndexOutOfBoundsException: 2 at GuessingGame.gameLogic(GuessingGame.java:77) at GuessingGame.paint(GuessingGame.java:55) at java.awt.Container.update(Container.java:1801) at sun.awt.RepaintArea.updateComponent(RepaintArea.java:239) at sun.awt.RepaintArea.paint(RepaintArea.java:216) at sun.awt.windows.WComponentPeer.handleEvent(WComponentPeer.java:306) at java.awt.Component.dispatchEventImpl(Component.java:4706) at java.awt.Container.dispatchEventImpl(Container.java:2099) at java.awt.Component.dispatchEvent(Component.java:4460) at java.awt.EventQueue.dispatchEvent(EventQueue.java:599) at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:269) at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:184) at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:174) at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:169) at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:161) at java.awt.EventDispatchThread.run(EventDispatchThread.java:122)

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  • Mass Ball-to-Ball Collision Handling (as in, lots of balls)

    - by BlueThen
    Update: Found out that I was using the radius as the diameter, which was why the mtd was overcompensating. Hi, StackOverflow. I've written a Processing program awhile back simulating ball physics. Basically, I have a large number of balls (1000), with gravity turned on. Detection works great, but my issue is that they start acting weird when they're bouncing against other balls in all directions. I'm pretty confident this involves the handling. For the most part, I'm using Jay Conrod's code. One part that's different is if (distance > 1.0) return; which I've changed to if (distance < 1.0) return; because the collision wasn't even being performed with the first bit of code, I'm guessing that's a typo. The balls overlap when I use his code, which isn't what I was looking for. My attempt to fix it was to move the balls to the edge of each other: float angle = atan2(y - collider.y, x - collider.x); float distance = dist(x,y, balls[ID2].x,balls[ID2].y); x = collider.x + radius * cos(angle); y = collider.y + radius * sin(angle); This isn't correct, I'm pretty sure of that. I tried the correction algorithm in the previous ball-to-ball topic: // get the mtd Vector2d delta = (position.subtract(ball.position)); float d = delta.getLength(); // minimum translation distance to push balls apart after intersecting Vector2d mtd = delta.multiply(((getRadius() + ball.getRadius())-d)/d); // resolve intersection -- // inverse mass quantities float im1 = 1 / getMass(); float im2 = 1 / ball.getMass(); // push-pull them apart based off their mass position = position.add(mtd.multiply(im1 / (im1 + im2))); ball.position = ball.position.subtract(mtd.multiply(im2 / (im1 + im2))); except my version doesn't use vectors, and every ball's weight is 1. The resulting code I get is this: PVector delta = new PVector(collider.x - x, collider.y - y); float d = delta.mag(); PVector mtd = new PVector(delta.x * ((radius + collider.radius - d) / d), delta.y * ((radius + collider.radius - d) / d)); // push-pull apart based on mass x -= mtd.x * 0.5; y -= mtd.y * 0.5; collider.x += mtd.x * 0.5; collider.y += mtd.y * 0.5; This code seems to over-correct collisions. Which doesn't make sense to me because in no other way do I modify the x and y values of each ball, other than this. Some other part of my code could be wrong, but I don't know. Here's the snippet of the entire ball-to-ball collision handling I'm using: if (alreadyCollided.contains(new Integer(ID2))) // if the ball has already collided with this, then we don't need to reperform the collision algorithm return; Ball collider = (Ball) objects.get(ID2); PVector collision = new PVector(x - collider.x, y - collider.y); float distance = collision.mag(); if (distance == 0) { collision = new PVector(1,0); distance = 1; } if (distance < 1) return; PVector velocity = new PVector(vx,vy); PVector velocity2 = new PVector(collider.vx, collider.vy); collision.div(distance); // normalize the distance float aci = velocity.dot(collision); float bci = velocity2.dot(collision); float acf = bci; float bcf = aci; vx += (acf - aci) * collision.x; vy += (acf - aci) * collision.y; collider.vx += (bcf - bci) * collision.x; collider.vy += (bcf - bci) * collision.y; alreadyCollided.add(new Integer(ID2)); collider.alreadyCollided.add(new Integer(ID)); PVector delta = new PVector(collider.x - x, collider.y - y); float d = delta.mag(); PVector mtd = new PVector(delta.x * ((radius + collider.radius - d) / d), delta.y * ((radius + collider.radius - d) / d)); // push-pull apart based on mass x -= mtd.x * 0.2; y -= mtd.y * 0.2; collider.x += mtd.x * 0.2; collider.y += mtd.y * 0.2; Thanks. (Apologies for lack of sources, stackoverflow thinks I'm a spammer)

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  • Watching a variable for changes without polling.

    - by milkfilk
    I'm using a framework called Processing which is basically a Java applet. It has the ability to do key events because Applet can. You can also roll your own callbacks of sorts into the parent. I'm not doing that right now and maybe that's the solution. For now, I'm looking for a more POJO solution. So I wrote some examples to illustrate my question. Please ignore using key events on the command line (console). Certainly this would be a very clean solution but it's not possible on the command line and my actual app isn't a command line app. In fact, a key event would be a good solution for me but I'm trying to understand events and polling beyond just keyboard specific problems. Both these examples flip a boolean. When the boolean flips, I want to fire something once. I could wrap the boolean in an Object so if the Object changes, I could fire an event too. I just don't want to poll with an if() statement unnecessarily. import java.io.BufferedReader; import java.io.IOException; import java.io.InputStreamReader; /* * Example of checking a variable for changes. * Uses dumb if() and polls continuously. */ public class NotAvoidingPolling { public static void main(String[] args) { boolean typedA = false; String input = ""; System.out.println("Type 'a' please."); while (true) { InputStreamReader isr = new InputStreamReader(System.in); BufferedReader br = new BufferedReader(isr); try { input = br.readLine(); } catch (IOException ioException) { System.out.println("IO Error."); System.exit(1); } // contrived state change logic if (input.equals("a")) { typedA = true; } else { typedA = false; } // problem: this is polling. if (typedA) System.out.println("Typed 'a'."); } } } Running this outputs: Type 'a' please. a Typed 'a'. On some forums people suggested using an Observer. And although this decouples the event handler from class being observed, I still have an if() on a forever loop. import java.io.BufferedReader; import java.io.IOException; import java.io.InputStreamReader; import java.util.Observable; import java.util.Observer; /* * Example of checking a variable for changes. * This uses an observer to decouple the handler feedback * out of the main() but still is polling. */ public class ObserverStillPolling { boolean typedA = false; public static void main(String[] args) { // this ObserverStillPolling o = new ObserverStillPolling(); final MyEvent myEvent = new MyEvent(o); final MyHandler myHandler = new MyHandler(); myEvent.addObserver(myHandler); // subscribe // watch for event forever Thread thread = new Thread(myEvent); thread.start(); System.out.println("Type 'a' please."); String input = ""; while (true) { InputStreamReader isr = new InputStreamReader(System.in); BufferedReader br = new BufferedReader(isr); try { input = br.readLine(); } catch (IOException ioException) { System.out.println("IO Error."); System.exit(1); } // contrived state change logic // but it's decoupled now because there's no handler here. if (input.equals("a")) { o.typedA = true; } } } } class MyEvent extends Observable implements Runnable { // boolean typedA; ObserverStillPolling o; public MyEvent(ObserverStillPolling o) { this.o = o; } public void run() { // watch the main forever while (true) { // event fire if (this.o.typedA) { setChanged(); // in reality, you'd pass something more useful notifyObservers("You just typed 'a'."); // reset this.o.typedA = false; } } } } class MyHandler implements Observer { public void update(Observable obj, Object arg) { // handle event if (arg instanceof String) { System.out.println("We received:" + (String) arg); } } } Running this outputs: Type 'a' please. a We received:You just typed 'a'. I'd be ok if the if() was a NOOP on the CPU. But it's really comparing every pass. I see real CPU load. This is as bad as polling. I can maybe throttle it back with a sleep or compare the elapsed time since last update but this is not event driven. It's just less polling. So how can I do this smarter? How can I watch a POJO for changes without polling? In C# there seems to be something interesting called properties. I'm not a C# guy so maybe this isn't as magical as I think. private void SendPropertyChanging(string property) { if (this.PropertyChanging != null) { this.PropertyChanging(this, new PropertyChangingEventArgs(property)); } }

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  • How to find an entry-level job after you already have a graduate degree?

    - by Uri
    Note: I asked this question in early 2009. A couple of months later, I found a great job. I've previously updated this question with some tips for whoever ends up in a similar situation, and now cleaned it up a little for the benefit of the fresh batch of graduates. Original post: In my early 20s I abandoned a great C++ development career path in a major company to go to graduate school and get a research masters (3 years). I did another year in industrial research, and then moved to the US to attend graduate school again, getting another masters and a Ph.D in software engineering from a top school (another 6 years down the drain). I was coding the whole way throughout my degrees (core Java and Eclipse plug-ins) and working on research related to software engineering (usability of APIs). I ended up graduating the year of the recession, with a son on the way and the prospects of no healthcare. Academic jobs and industrial research jobs are quite scarce. Initially, I was naive, thinking that with my background, I could easily find a coding job. Big mistake. It turns out that I'm in a complicated position. Entry level positions are usually offered to college undergraduates. I attended my school's career fairs, but you could immediately see signs of Ph.D. aversion and overqualification issues. Some of the recruiters I spoke with explicitly told me that they wanted 20 year olds with clean slates, and some were looking for interns since they are in various forms of hiring freezes. I managed to get a couple of interviews from these career fairs and through recruiters. However, since I've been out of school for a long time and programming primarily in Java, I am also no longer proficient in C/C++ and the usual range of college-level interview questions that everyone uses. I had no problems with this when I was 19 and interviewing for my first job since a lot of what you do in C is manipulate pointers and I was coding C++ for fun and for school. Later I was routinely doing pointer manipulation on the job, and during my first masters taught college courses with data structures and C++. But even though I remember many properties of C++ well, it's been close to ten years since I regularly used C++ and pointers. As a Java developer I rarely had to work at this level, but experience in OOD and in writing good maintainable code is meaningless for C++ interviews. Reading books as a refresh and looking at sample code did not do the trick. I also looked at mid-to-senior level Java positions, but most of them focused on J2EE APIs rather than on core Java and required a certain number of years in industrial positions. Coding research tools and prior C++ experience doesn't count. So that sends me back to entry-level jobs that are posted through job-boards, and these are not common (mostly they are Monster junk), and small companies are even less likely to answer a Ph.D. compared to the giants who participate in top-10 career fairs. Even worse, in many companies initial screening is done by HR folks who really don't want to deal with anything anomalous like a Ph.D. Any tips on how I should approach this intractable position? For example, what should I write in cover letters? Note that while immigration is not an issue for me, I cannot go freelance as I need the benefits (and in particular group health insurance). During my studies I had no time to contribute to open-source projects or maintain a popular blog, so even if I invested in that now there would be no immediate benefit. Updates: In the two months after posting this I received several offers to work as a core Java developer in the financial industry and accepted one from a firm where I am working to this day. For those who find themselves in similar situations, here are my tips: Give up on trying to find an entry level positions. You can't undo time. Accept the fact that there is Ph.D. discrimination in the job market (some might say rightfully so). It is legal to discriminate based on education. No point fighting it. The most important tip is to focus on the language you are comfortable with. The sad truth about programming in a particular language is that it is not like riding a bike. If you haven't used a language in the last few years, and can't actually apply it routinely (not just as a refresher) before you start your search, it is going to be very difficult to do well in an interview. Now that I'm interviewing others, I routinely see it in folks with a mixed C++/Java background. We maintain "a shadow" of the old language but end up with a weird mix that makes it hard to interview on either. Entry-level folks are at an advantage here since they usually have one language. Memory can help you do great in a screening interview, but without recent day-to-day experience, code tests will be difficult. Despite the supposed relation, core Java programming and J2EE programming are two different things with different skillsets. If you come from academia, you likely have very little J2EE experience and may find it hard to get accepted for a J2EE job. J2EE jobs seem to have a larger list of acronyms in their requirements. In addition, from interviewing J2EE developers it seems that for many there is a focus on mastering specific APIs and architectures, whereas core Java development tends to be secondary. In the same way that I can no longer manipulate pointers well, a J2EE developer may have difficulties doing low level Java manipulation. This puts you at a relative advantage in competing for core Java jobs! If you are able to work for startups (in terms of family life and stability) or migrate to startup-rich areas such as the west coast, you can find many exciting opportunities where advanced degrees are a benefit. I've since been approached by several startups, although I had to decline. Work through a recruiter if possible. They have direct contacts with the hiring parties, allowing you to "stand out". It is better to get a clear yes/no confirmation from a recruiter on whether a company might be interested in interviewing you, than it is to send your resume and hope that someone will ever see it. Recruiters are also a great way of bypassing HR. However, also beware of recruiters. They have a vested interest and will go to various shady practices and pressure tactics. To find a good recruiter, talk to a friend who declined a job offer he got through a recruiter. A good recruiter, to me, is measured in how they handle that. Interview for the jobs that require your core strength. If you're rusty or entirely unfamiliar with a technology around which the job revolves, you're probably not a good match. Yes, you probably have the talent to master them, but most companies would want "instant gratification". I got my offers from companies that wanted core Java developer. I didn't do well on places that wanted advance C++ because I am too rusty and not up to date on recent libraries. I also didn't hear from companies that wanted lots of J2EE experience, and that's ok. Finding companies that want core Java without web is harder, but exists in specific industries (e.g., finance, defense). This requires a lot more legwork in terms of search, but these jobs do exist. There are different interview styles. Some companies focus on puzzles, some companies focus on algorithms, and some companies focus on design and coding skills. I had the most success in places where the questions were the most related to the function I would have been performing. Pick companies accordingly as well.

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  • Dynamic scoping in Clojure?

    - by j-g-faustus
    Hi, I'm looking for an idiomatic way to get dynamically scoped variables in Clojure (or a similar effect) for use in templates and such. Here is an example problem using a lookup table to translate tag attributes from some non-HTML format to HTML, where the table needs access to a set of variables supplied from elsewhere: (def *attr-table* ; Key: [attr-key tag-name] or [boolean-function] ; Value: [attr-key attr-value] (empty array to ignore) ; Context: Variables "tagname", "akey", "aval" '( ; translate :LINK attribute in <a> to :href [:LINK "a"] [:href aval] ; translate :LINK attribute in <img> to :src [:LINK "img"] [:src aval] ; throw exception if :LINK attribute in any other tag [:LINK] (throw (RuntimeException. (str "No match for " tagname))) ; ... more rules ; ignore string keys, used for internal bookkeeping [(string? akey)] [] )) ; ignore I want to be able to evaluate the rules (left hand side) as well as the result (right hand side), and need some way to put the variables in scope at the location where the table is evaluated. I also want to keep the lookup and evaluation logic independent of any particular table or set of variables. I suppose there are similar issues involved in templates (for example for dynamic HTML), where you don't want to rewrite the template processing logic every time someone puts a new variable in a template. Here is one approach using global variables and bindings. I have included some logic for the table lookup: ;; Generic code, works with any table on the same format. (defn rule-match? [rule-val test-val] "true if a single rule matches a single argument value" (cond (not (coll? rule-val)) (= rule-val test-val) ; plain value (list? rule-val) (eval rule-val) ; function call :else false )) (defn rule-lookup [test-val rule-table] "looks up rule match for test-val. Returns result or nil." (loop [rules (partition 2 rule-table)] (when-not (empty? rules) (let [[select result] (first rules)] (if (every? #(boolean %) (map rule-match? select test-val)) (eval result) ; evaluate and return result (recur (rest rules)) ))))) ;; Code specific to *attr-table* (def tagname) ; need these globals for the binding in html-attr (def akey) (def aval) (defn html-attr [tagname h-attr] "converts to html attributes" (apply hash-map (flatten (map (fn [[k v :as kv]] (binding [tagname tagname akey k aval v] (or (rule-lookup [k tagname] *attr-table*) kv))) h-attr )))) (defn test-attr [] "test conversion" (prn "a" (html-attr "a" {:LINK "www.google.com" "internal" 42 :title "A link" })) (prn "img" (html-attr "img" {:LINK "logo.png" }))) user=> (test-attr) "a" {:href "www.google.com", :title "A link"} "img" {:src "logo.png"} This is nice in that the lookup logic is independent of the table, so it can be reused with other tables and different variables. (Plus of course that the general table approach is about a quarter of the size of the code I had when I did the translations "by hand" in a giant cond.) It is not so nice in that I need to declare every variable as a global for the binding to work. Here is another approach using a "semi-macro", a function with a syntax-quoted return value, that doesn't need globals: (defn attr-table [tagname akey aval] `( [:LINK "a"] [:href ~aval] [:LINK "img"] [:src ~aval] [:LINK] (throw (RuntimeException. (str "No match for " tagname))) ; ... more rules [(string? ~akey)] [] ))) Only a couple of changes are needed to the rest of the code: In rule-match?, when syntax-quoted the function call is no longer a list: - (list? rule-val) (eval rule-val) + (seq? rule-val) (eval rule-val) In html-attr: - (binding [tagname tagname akey k aval v] - (or (rule-lookup [k tagname] *attr-table*) kv))) + (or (rule-lookup [k tagname] (attr-table tagname k v)) kv))) And we get the same result without globals. (And without dynamic scoping.) Are there other alternatives to pass along sets of variable bindings declared elsewhere, without the globals required by Clojure's binding? Is there an idiomatic way of doing it, like Ruby's binding or Javascript's function.apply(context)?

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  • How to setup custom DNS with Azure Websites Preview?

    - by husainnz
    I created a new Azure Website, using Umbraco as the CMS. I got a page up and going, and I already have a .co.nz domain with www.domains4less.com. There's a whole lot of stuff on the internet about pointing URLs to Azure, but that seems to be more of a redirection service than anything (i.e. my URLs still use azurewebsites.net once I land on my site). Has anybody had any luck getting it to go? Here's the error I get when I try adding the DNS entry to Azure (I'm in reserved mode, reemdairy is the name of the website): There was an error processing your request. Please try again in a few moments. Browser: 5.0 (Windows NT 6.1; WOW64) AppleWebKit/536.5 (KHTML, like Gecko) Chrome/19.0.1084.56 Safari/536.5 User language: undefined Portal Version: 6.0.6002.18488 (rd_auxportal_stable.120609-0259) Subscriptions: 3aabe358-d178-4790-a97b-ffba902b2851 User email address: [email protected] Last 10 Requests message: Failure: Ajax call to: Websites/UpdateConfig. failed with status: error (500) in 2.57 seconds. x-ms-client-request-id was: 38834edf-c9f3-46bb-a1f7-b2839c692bcf-2012-06-12 22:25:14Z dateTime: Wed Jun 13 2012 10:25:17 GMT+1200 (New Zealand Standard Time) durationSeconds: 2.57 url: Websites/UpdateConfig status: 500 textStatus: error clientMsRequestId: 38834edf-c9f3-46bb-a1f7-b2839c692bcf-2012-06-12 22:25:14Z sessionId: 09c72263-6ce7-422b-84d7-4c21acded759 referrer: https://manage.windowsazure.com/#Workspaces/WebsiteExtension/Website/reemdairy/configure host: manage.windowsazure.com response: {"message":"Try again. Contact support if the problem persists.","ErrorMessage":"Try again. Contact support if the problem persists.","httpStatusCode":"InternalServerError","operationTrackingId":"","stackTrace":null} message: Complete: Ajax call to: Websites/GetConfig. completed with status: success (200) in 1.021 seconds. x-ms-client-request-id was: a0cdcced-13d0-44e2-866d-e0b061b9461b-2012-06-12 22:24:43Z dateTime: Wed Jun 13 2012 10:24:44 GMT+1200 (New Zealand Standard Time) durationSeconds: 1.021 url: Websites/GetConfig status: 200 textStatus: success clientMsRequestId: a0cdcced-13d0-44e2-866d-e0b061b9461b-2012-06-12 22:24:43Z sessionId: 09c72263-6ce7-422b-84d7-4c21acded759 referrer: https://manage.windowsazure.com/#Workspaces/WebsiteExtension/Website/reemdairy/configure host: manage.windowsazure.com message: Complete: Ajax call to: https://manage.windowsazure.com/Service/OperationTracking?subscriptionId=3aabe358-d178-4790-a97b-ffba902b2851. completed with status: success (200) in 1.887 seconds. x-ms-client-request-id was: a7689fe9-b9f9-4d6c-8926-734ec9a0b515-2012-06-12 22:24:40Z dateTime: Wed Jun 13 2012 10:24:42 GMT+1200 (New Zealand Standard Time) durationSeconds: 1.887 url: https://manage.windowsazure.com/Service/OperationTracking?subscriptionId=3aabe358-d178-4790-a97b-ffba902b2851 status: 200 textStatus: success clientMsRequestId: a7689fe9-b9f9-4d6c-8926-734ec9a0b515-2012-06-12 22:24:40Z sessionId: 09c72263-6ce7-422b-84d7-4c21acded759 referrer: https://manage.windowsazure.com/#Workspaces/WebsiteExtension/Website/reemdairy/configure host: manage.windowsazure.com message: Complete: Ajax call to: /Service/GetUserSettings. completed with status: success (200) in 0.941 seconds. x-ms-client-request-id was: 805e554d-1e2e-4214-afd5-be87c0f255d1-2012-06-12 22:24:40Z dateTime: Wed Jun 13 2012 10:24:40 GMT+1200 (New Zealand Standard Time) durationSeconds: 0.941 url: /Service/GetUserSettings status: 200 textStatus: success clientMsRequestId: 805e554d-1e2e-4214-afd5-be87c0f255d1-2012-06-12 22:24:40Z sessionId: 09c72263-6ce7-422b-84d7-4c21acded759 referrer: https://manage.windowsazure.com/#Workspaces/WebsiteExtension/Website/reemdairy/configure host: manage.windowsazure.com message: Complete: Ajax call to: Extensions/ApplicationsExtension/SqlAzure/ClusterSuffix. completed with status: success (200) in 0.483 seconds. x-ms-client-request-id was: 85157ceb-c538-40ca-8c1e-5cc07c57240f-2012-06-12 22:24:39Z dateTime: Wed Jun 13 2012 10:24:40 GMT+1200 (New Zealand Standard Time) durationSeconds: 0.483 url: Extensions/ApplicationsExtension/SqlAzure/ClusterSuffix status: 200 textStatus: success clientMsRequestId: 85157ceb-c538-40ca-8c1e-5cc07c57240f-2012-06-12 22:24:39Z sessionId: 09c72263-6ce7-422b-84d7-4c21acded759 referrer: https://manage.windowsazure.com/#Workspaces/WebsiteExtension/Website/reemdairy/configure host: manage.windowsazure.com message: Complete: Ajax call to: Extensions/ApplicationsExtension/SqlAzure/GetClientIp. completed with status: success (200) in 0.309 seconds. x-ms-client-request-id was: 2eb194b6-66ca-49e2-9016-e0f89164314c-2012-06-12 22:24:39Z dateTime: Wed Jun 13 2012 10:24:40 GMT+1200 (New Zealand Standard Time) durationSeconds: 0.309 url: Extensions/ApplicationsExtension/SqlAzure/GetClientIp status: 200 textStatus: success clientMsRequestId: 2eb194b6-66ca-49e2-9016-e0f89164314c-2012-06-12 22:24:39Z sessionId: 09c72263-6ce7-422b-84d7-4c21acded759 referrer: https://manage.windowsazure.com/#Workspaces/WebsiteExtension/Website/reemdairy/configure host: manage.windowsazure.com message: Complete: Ajax call to: Extensions/ApplicationsExtension/SqlAzure/DefaultServerLocation. completed with status: success (200) in 0.309 seconds. x-ms-client-request-id was: 1bc165ef-2081-48f2-baed-16c6edf8ea67-2012-06-12 22:24:39Z dateTime: Wed Jun 13 2012 10:24:40 GMT+1200 (New Zealand Standard Time) durationSeconds: 0.309 url: Extensions/ApplicationsExtension/SqlAzure/DefaultServerLocation status: 200 textStatus: success clientMsRequestId: 1bc165ef-2081-48f2-baed-16c6edf8ea67-2012-06-12 22:24:39Z sessionId: 09c72263-6ce7-422b-84d7-4c21acded759 referrer: https://manage.windowsazure.com/#Workspaces/WebsiteExtension/Website/reemdairy/configure host: manage.windowsazure.com message: Complete: Ajax call to: Extensions/ApplicationsExtension/SqlAzure/ServerLocations. completed with status: success (200) in 0.309 seconds. x-ms-client-request-id was: e1fba7df-6a12-47f8-9434-bf17ca7d93f4-2012-06-12 22:24:39Z dateTime: Wed Jun 13 2012 10:24:40 GMT+1200 (New Zealand Standard Time) durationSeconds: 0.309 url: Extensions/ApplicationsExtension/SqlAzure/ServerLocations status: 200 textStatus: success clientMsRequestId: e1fba7df-6a12-47f8-9434-bf17ca7d93f4-2012-06-12 22:24:39Z sessionId: 09c72263-6ce7-422b-84d7-4c21acded759 referrer: https://manage.windowsazure.com/#Workspaces/WebsiteExtension/Website/reemdairy/configure host: manage.windowsazure.com

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  • Server Error in '/' Application (ASP.NET)

    - by baeltazor
    Hi All I just setup up member ship roles and registration on my website with visual web developer using the tutorial on msdn. It works perfectly locally, but when i uploaded it to my server, I get the following page: "Server Error in '/' Application. -------------------------------------------------------------------------------- Configuration Error Description: An error occurred during the processing of a configuration file required to service this request. Please review the specific error details below and modify your configuration file appropriately. Parser Error Message: The connection name 'LocalSqlServer' was not found in the applications configuration or the connection string is empty. Source Error: [No relevant source lines] Source File: machine.config Line: 160 -------------------------------------------------------------------------------- Version Information: Microsoft .NET Framework Version:2.0.50727.4200; ASP.NET Version:2.0.50727.4016 " Does anybody know why I'm seeing this and how I may go about fixinf this? Any help is greatly appreciated. Thank you Bael. EDIT: I have just looked at my web.config file after reading the following line in the error message: "The connection name 'LocalSqlServer' was not found in the applications configuration or the connection string is empty." ... And have noticed that the following element is completely empty: <connectionStrings/> // Is this one supposed to be empty? if not what should go here? In the error it implies it shouldn't be empty. Also, I don't know where I should place LocalSqlServer LATEST EDIT After changing DataSource to LocalHost i get the following error: Server Error in '/JTS' Application. -------------------------------------------------------------------------------- A network-related or instance-specific error occurred while establishing a connection to SQL Server. The server was not found or was not accessible. Verify that the instance name is correct and that SQL Server is configured to allow remote connections. (provider: Named Pipes Provider, error: 40 - Could not open a connection to SQL Server) Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code. Exception Details: System.Data.SqlClient.SqlException: A network-related or instance-specific error occurred while establishing a connection to SQL Server. The server was not found or was not accessible. Verify that the instance name is correct and that SQL Server is configured to allow remote connections. (provider: Named Pipes Provider, error: 40 - Could not open a connection to SQL Server) Source Error: An unhandled exception was generated during the execution of the current web request. Information regarding the origin and location of the exception can be identified using the exception stack trace below. Stack Trace: [SqlException (0x80131904): A network-related or instance-specific error occurred while establishing a connection to SQL Server. The server was not found or was not accessible. Verify that the instance name is correct and that SQL Server is configured to allow remote connections. (provider: Named Pipes Provider, error: 40 - Could not open a connection to SQL Server)] System.Data.SqlClient.SqlInternalConnection.OnError(SqlException exception, Boolean breakConnection) +4849015 System.Data.SqlClient.TdsParser.ThrowExceptionAndWarning(TdsParserStateObject stateObj) +194 System.Data.SqlClient.TdsParser.Connect(ServerInfo serverInfo, SqlInternalConnectionTds connHandler, Boolean ignoreSniOpenTimeout, Int64 timerExpire, Boolean encrypt, Boolean trustServerCert, Boolean integratedSecurity, SqlConnection owningObject) +4862333 System.Data.SqlClient.SqlInternalConnectionTds.AttemptOneLogin(ServerInfo serverInfo, String newPassword, Boolean ignoreSniOpenTimeout, Int64 timerExpire, SqlConnection owningObject) +90 System.Data.SqlClient.SqlInternalConnectionTds.LoginNoFailover(String host, String newPassword, Boolean redirectedUserInstance, SqlConnection owningObject, SqlConnectionString connectionOptions, Int64 timerStart) +342 System.Data.SqlClient.SqlInternalConnectionTds.OpenLoginEnlist(SqlConnection owningObject, SqlConnectionString connectionOptions, String newPassword, Boolean redirectedUserInstance) +221 System.Data.SqlClient.SqlInternalConnectionTds..ctor(DbConnectionPoolIdentity identity, SqlConnectionString connectionOptions, Object providerInfo, String newPassword, SqlConnection owningObject, Boolean redirectedUserInstance) +189 System.Data.SqlClient.SqlConnectionFactory.CreateConnection(DbConnectionOptions options, Object poolGroupProviderInfo, DbConnectionPool pool, DbConnection owningConnection) +185 System.Data.ProviderBase.DbConnectionFactory.CreatePooledConnection(DbConnection owningConnection, DbConnectionPool pool, DbConnectionOptions options) +31 System.Data.ProviderBase.DbConnectionPool.CreateObject(DbConnection owningObject) +433 System.Data.ProviderBase.DbConnectionPool.UserCreateRequest(DbConnection owningObject) +66 System.Data.ProviderBase.DbConnectionPool.GetConnection(DbConnection owningObject) +499 System.Data.ProviderBase.DbConnectionFactory.GetConnection(DbConnection owningConnection) +65 System.Data.ProviderBase.DbConnectionClosed.OpenConnection(DbConnection outerConnection, DbConnectionFactory connectionFactory) +117 System.Data.SqlClient.SqlConnection.Open() +122 System.Web.DataAccess.SqlConnectionHolder.Open(HttpContext context, Boolean revertImpersonate) +87 System.Web.DataAccess.SqlConnectionHelper.GetConnection(String connectionString, Boolean revertImpersonation) +221 System.Web.Security.SqlMembershipProvider.GetPasswordWithFormat(String username, Boolean updateLastLoginActivityDate, Int32& status, String& password, Int32& passwordFormat, String& passwordSalt, Int32& failedPasswordAttemptCount, Int32& failedPasswordAnswerAttemptCount, Boolean& isApproved, DateTime& lastLoginDate, DateTime& lastActivityDate) +815 System.Web.Security.SqlMembershipProvider.CheckPassword(String username, String password, Boolean updateLastLoginActivityDate, Boolean failIfNotApproved, String& salt, Int32& passwordFormat) +105 System.Web.Security.SqlMembershipProvider.CheckPassword(String username, String password, Boolean updateLastLoginActivityDate, Boolean failIfNotApproved) +42 System.Web.Security.SqlMembershipProvider.ValidateUser(String username, String password) +78 System.Web.UI.WebControls.Login.AuthenticateUsingMembershipProvider(AuthenticateEventArgs e) +60 System.Web.UI.WebControls.Login.OnAuthenticate(AuthenticateEventArgs e) +119 System.Web.UI.WebControls.Login.AttemptLogin() +115 System.Web.UI.WebControls.Login.OnBubbleEvent(Object source, EventArgs e) +101 System.Web.UI.Control.RaiseBubbleEvent(Object source, EventArgs args) +37 System.Web.UI.WebControls.Button.OnCommand(CommandEventArgs e) +118 System.Web.UI.WebControls.Button.RaisePostBackEvent(String eventArgument) +166 System.Web.UI.WebControls.Button.System.Web.UI.IPostBackEventHandler.RaisePostBackEvent(String eventArgument) +10 System.Web.UI.Page.RaisePostBackEvent(IPostBackEventHandler sourceControl, String eventArgument) +13 System.Web.UI.Page.RaisePostBackEvent(NameValueCollection postData) +36 System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) +1565 -------------------------------------------------------------------------------- Version Information: Microsoft .NET Framework Version:2.0.50727.4927; ASP.NET Version:2.0.50727.4927

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  • XSLT Transforming sequential XML to hierarchical XML

    - by Jean-Paul Smit
    I have a requirement to transform a sequential XML node list into a hierarchical, but I run into some XSLT specific knowledge gap. The input XML contains articles, colors and sizes. In the sample below 'Record1' is an article, 'Record2' represents a color and 'Record3' are the sizes. The number of colors and sizes (record2 and record3) elements can vary. <root> <Record1>...</Record1> <Record2>...</Record2> <Record3>...</Record3> <Record3>...</Record3> <Record2>...</Record2> <Record3>...</Record3> <Record3>...</Record3> <Record3>...</Record3> <Record3>...</Record3> <Record1>...</Record1> <Record2>...</Record2> <Record3>...</Record3> <Record3>...</Record3> <Record2>...</Record2> <Record3>...</Record3> <Record3>...</Record3> <Record3>...</Record3> <Record3>...</Record3> </root> All fields are on the same hierarchical level, but still I have to create this structure as output: <root> <article> -> Record1 <color> -> Record2 <size>...</size> -> Record3 <size>...</size> -> Record3 </color> <color> -> Record2 <size>...</size> -> Record3 <size>...</size> -> Record3 <size>...</size> -> Record3 <size>...</size> -> Record3 </color> </article> <article> -> Record1 <color> -> Record2 <size>...</size> -> Record3 <size>...</size> -> Record3 </color> <color> -> Record2 <size>...</size> -> Record3 <size>...</size> -> Record3 <size>...</size> -> Record3 <size>...</size> -> Record3 </color> </article> </root> I've tried to iterate the nodes sequentially but for example the 'article' (=record1) node tag needs to remain unclosed while 'color' (=record2) nodes are processed. The same counts for processing 'size' (=record3) having 'color' unclosed, but that is not allowed by XSLT. My next idea was to call a template for every article, color and size level, but I don't know how to select for example all 'record3' nodes between the current 'record2' and the next article represented by 'record1'. I've also got a limitation on the XSLT version because I need this transformation in BizTalk Server which only supports XSLT 1.0 Can someone push me in the right direction?

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  • another question about OpenGL ES rendering to texture

    - by ensoreus
    Hello, pros and gurus! Here is another question about rendering to texture. The whole stuff is all about saving texture between passing image into different filters. Maybe all iPhone developers knows about Apple's sample code with OpenGL processing where they used GL filters(functions), but pass into them the same source image. I need to edit an image by passing it sequentelly with saving the state of the image to edit. I am very noob in OpenGL, so I spent increadibly a lot of to solve the issue. So, I desided to create 2 FBO's and attach source image and temporary image as a textures to render in. Here is my init routine: glEnableClientState(GL_VERTEX_ARRAY); glEnableClientState(GL_TEXTURE_COORD_ARRAY); glEnable(GL_TEXTURE_2D); glPixelStorei(GL_UNPACK_ALIGNMENT, 1); glGetIntegerv(GL_FRAMEBUFFER_BINDING_OES, (GLint *)&SystemFBO); glImage = [self loadTexture:preparedImage]; //source image for (int i = 0; i < 4; i++) { fullquad[i].s *= glImage->s; fullquad[i].t *= glImage->t; flipquad[i].s *= glImage->s; flipquad[i].t *= glImage->t; } tmpImage = [self loadEmptyTexture]; //editing image glGenFramebuffersOES(1, &tmpImageFBO); glBindFramebufferOES(GL_FRAMEBUFFER_OES, tmpImageFBO); glFramebufferTexture2DOES(GL_FRAMEBUFFER_OES, GL_COLOR_ATTACHMENT0_OES, GL_TEXTURE_2D, tmpImage->texID, 0); GLenum status = glCheckFramebufferStatusOES(GL_FRAMEBUFFER_OES); if(status != GL_FRAMEBUFFER_COMPLETE_OES) { NSLog(@"failed to make complete tmp framebuffer object %x", status); } glBindTexture(GL_TEXTURE_2D, 0); glBindFramebufferOES(GL_FRAMEBUFFER_OES, 0); glGenRenderbuffersOES(1, &glImageFBO); glBindFramebufferOES(GL_FRAMEBUFFER_OES, glImageFBO); glFramebufferTexture2DOES(GL_FRAMEBUFFER_OES, GL_COLOR_ATTACHMENT0_OES, GL_TEXTURE_2D, glImage->texID, 0); status = glCheckFramebufferStatusOES(GL_FRAMEBUFFER_OES) ; if(status != GL_FRAMEBUFFER_COMPLETE_OES) { NSLog(@"failed to make complete cur framebuffer object %x", status); } glBindTexture(GL_TEXTURE_2D, 0); glBindFramebufferOES(GL_FRAMEBUFFER_OES, 0); When user drag the slider, this routine invokes to apply changes -(void)setContrast:(CGFloat)value{ contrast = value; if(flag!=mfContrast){ NSLog(@"contrast: dumped"); flag = mfContrast; glBindFramebufferOES(GL_FRAMEBUFFER_OES, glImageFBO); glClearColor(1,1,1,1); glClear(GL_COLOR_BUFFER_BIT|GL_DEPTH_BUFFER_BIT); glMatrixMode(GL_PROJECTION); glLoadIdentity(); glOrthof(0, 512, 0, 512, -1, 1); glMatrixMode(GL_MODELVIEW); glLoadIdentity(); glScalef(512, 512, 1); glBindTexture(GL_TEXTURE_2D, tmpImage->texID); glViewport(0, 0, 512, 512); glVertexPointer(2, GL_FLOAT, sizeof(V2fT2f), &fullquad[0].x); glTexCoordPointer(2, GL_FLOAT, sizeof(V2fT2f), &fullquad[0].s); glDrawArrays(GL_TRIANGLE_STRIP, 0, 4); glBindFramebufferOES(GL_FRAMEBUFFER_OES, 0); } glBindFramebufferOES(GL_FRAMEBUFFER_OES,tmpImageFBO); glClearColor(0,0,0,1); glClear(GL_COLOR_BUFFER_BIT); glEnable(GL_TEXTURE_2D); glActiveTexture(GL_TEXTURE0); glMatrixMode(GL_PROJECTION); glLoadIdentity(); glOrthof(0, 512, 0, 512, -1, 1); glMatrixMode(GL_MODELVIEW); glLoadIdentity(); glScalef(512, 512, 1); glBindTexture(GL_TEXTURE_2D, glImage->texID); glViewport(0, 0, 512, 512); [self contrastProc:fullquad value:contrast]; glBindFramebufferOES(GL_FRAMEBUFFER_OES, 0); [self redraw]; } Here are two cases: if it is the same filter(edit mode) to use, I bind tmpFBO to draw into tmpImage texture and edit glImage texture. contrastProc is a pure routine from Apples's sample. If it is another mode, than I save edited image by drawing tmpImage texture in source texture glImage, binded with glImageFBO. After that I call redraw: glBindFramebufferOES(GL_FRAMEBUFFER_OES, SystemFBO); glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT); glMatrixMode(GL_PROJECTION); glLoadIdentity(); glOrthof(0, kTexWidth, 0, kTexHeight, -1, 1); glMatrixMode(GL_MODELVIEW); glLoadIdentity(); glScalef(kTexWidth, kTexHeight, 1); glBindTexture(GL_TEXTURE_2D, glImage->texID); glViewport(0, 0, kTexWidth, kTexHeight); glVertexPointer(2, GL_FLOAT, sizeof(V2fT2f), &flipquad[0].x); glTexCoordPointer(2, GL_FLOAT, sizeof(V2fT2f), &flipquad[0].s); glDrawArrays(GL_TRIANGLE_STRIP, 0, 4); glBindFramebufferOES(GL_FRAMEBUFFER_OES, 0); And here it binds visual framebuffer and dispose glImage texture. So, the result is VERY aggresive filtering. Increasing contrast volume by just 0.2 brings image to state that comparable with 0.9 contrast volume in Apple's sample code project. I miss something obvious, I guess. Interesting, if I disabple line glBindTexture(GL_TEXTURE_2D, glImage->texID); in setContrast routine it brings no effect. At all. If I replace tmpImageFBO with SystemFBO to draw glImage directly on display(and disabling redraw invoking line), all works fine. Please, HELP ME!!! :(

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  • C++ Sentinel/Count Controlled Loop beginning programming

    - by Bryan Hendricks
    Hello all this is my first post. I'm working on a homework assignment with the following parameters. Piecework Workers are paid by the piece. Often worker who produce a greater quantity of output are paid at a higher rate. 1 - 199 pieces completed $0.50 each 200 - 399 $0.55 each (for all pieces) 400 - 599 $0.60 each 600 or more $0.65 each Input: For each worker, input the name and number of pieces completed. Name Pieces Johnny Begood 265 Sally Great 650 Sam Klutz 177 Pete Precise 400 Fannie Fantastic 399 Morrie Mellow 200 Output: Print an appropriate title and column headings. There should be one detail line for each worker, which shows the name, number of pieces, and the amount earned. Compute and print totals of the number of pieces and the dollar amount earned. Processing: For each person, compute the pay earned by multiplying the number of pieces by the appropriate price. Accumulate the total number of pieces and the total dollar amount paid. Sample Program Output: Piecework Weekly Report Name Pieces Pay Johnny Begood 265 145.75 Sally Great 650 422.50 Sam Klutz 177 88.5 Pete Precise 400 240.00 Fannie Fantastic 399 219.45 Morrie Mellow 200 110.00 Totals 2091 1226.20 You are required to code, compile, link, and run a sentinel-controlled loop program that transforms the input to the output specifications as shown in the above attachment. The input items should be entered into a text file named piecework1.dat and the ouput file stored in piecework1.out . The program filename is piecework1.cpp. Copies of these three files should be e-mailed to me in their original form. Read the name using a single variable as opposed to two different variables. To accomplish this, you must use the getline(stream, variable) function as discussed in class, except that you will replace the cin with your textfile stream variable name. Do not forget to code the compiler directive #include < string at the top of your program to acknowledge the utilization of the string variable, name . Your nested if-else statement, accumulators, count-controlled loop, should be properly designed to process the data correctly. The code below will run, but does not produce any output. I think it needs something around line 57 like a count control to stop the loop. something like (and this is just an example....which is why it is not in the code.) count = 1; while (count <=4) Can someone review the code and tell me what kind of count I need to introduce, and if there are any other changes that need to be made. Thanks. [code] //COS 502-90 //November 2, 2012 //This program uses a sentinel-controlled loop that transforms input to output. #include <iostream> #include <fstream> #include <iomanip> //output formatting #include <string> //string variables using namespace std; int main() { double pieces; //number of pieces made double rate; //amout paid per amount produced double pay; //amount earned string name; //name of worker ifstream inFile; ofstream outFile; //***********input statements**************************** inFile.open("Piecework1.txt"); //opens the input text file outFile.open("piecework1.out"); //opens the output text file outFile << setprecision(2) << showpoint; outFile << name << setw(6) << "Pieces" << setw(12) << "Pay" << endl; outFile << "_____" << setw(6) << "_____" << setw(12) << "_____" << endl; getline(inFile, name, '*'); //priming read inFile >> pieces >> pay >> rate; // ,, while (name != "End of File") //while condition test { //begining of loop pay = pieces * rate; getline(inFile, name, '*'); //get next name inFile >> pieces; //get next pieces } //end of loop inFile.close(); outFile.close(); return 0; }[/code]

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  • Improving HTML scrapper efficiency with pcntl_fork()

    - by Michael Pasqualone
    With the help from two previous questions, I now have a working HTML scrapper that feeds product information into a database. What I am now trying to do is improve efficiently by wrapping my brain around with getting my scrapper working with pcntl_fork. If I split my php5-cli script into 10 separate chunks, I improve total runtime by a large factor so I know I am not i/o or cpu bound but just limited by the linear nature of my scraping functions. Using code I've cobbled together from multiple sources, I have this working test: <?php libxml_use_internal_errors(true); ini_set('max_execution_time', 0); ini_set('max_input_time', 0); set_time_limit(0); $hrefArray = array("http://slashdot.org", "http://slashdot.org", "http://slashdot.org", "http://slashdot.org"); function doDomStuff($singleHref,$childPid) { $html = new DOMDocument(); $html->loadHtmlFile($singleHref); $xPath = new DOMXPath($html); $domQuery = '//div[@id="slogan"]/h2'; $domReturn = $xPath->query($domQuery); foreach($domReturn as $return) { $slogan = $return->nodeValue; echo "Child PID #" . $childPid . " says: " . $slogan . "\n"; } } $pids = array(); foreach ($hrefArray as $singleHref) { $pid = pcntl_fork(); if ($pid == -1) { die("Couldn't fork, error!"); } elseif ($pid > 0) { // We are the parent $pids[] = $pid; } else { // We are the child $childPid = posix_getpid(); doDomStuff($singleHref,$childPid); exit(0); } } foreach ($pids as $pid) { pcntl_waitpid($pid, $status); } // Clear the libxml buffer so it doesn't fill up libxml_clear_errors(); Which raises the following questions: 1) Given my hrefArray contains 4 urls - if the array was to contain say 1,000 product urls this code would spawn 1,000 child processes? If so, what is the best way to limit the amount of processes to say 10, and again 1,000 urls as an example split the child work load to 100 products per child (10 x 100). 2) I've learn that pcntl_fork creates a copy of the process and all variables, classes, etc. What I would like to do is replace my hrefArray variable with a DOMDocument query that builds the list of products to scrape, and then feeds them off to child processes to do the processing - so spreading the load across 10 child workers. My brain is telling I need to do something like the following (obviously this doesn't work, so don't run it): <?php libxml_use_internal_errors(true); ini_set('max_execution_time', 0); ini_set('max_input_time', 0); set_time_limit(0); $maxChildWorkers = 10; $html = new DOMDocument(); $html->loadHtmlFile('http://xxxx'); $xPath = new DOMXPath($html); $domQuery = '//div[@id=productDetail]/a'; $domReturn = $xPath->query($domQuery); $hrefsArray[] = $domReturn->getAttribute('href'); function doDomStuff($singleHref) { // Do stuff here with each product } // To figure out: Split href array into $maxChilderWorks # of workArray1, workArray2 ... workArray10. $pids = array(); foreach ($workArray(1,2,3 ... 10) as $singleHref) { $pid = pcntl_fork(); if ($pid == -1) { die("Couldn't fork, error!"); } elseif ($pid > 0) { // We are the parent $pids[] = $pid; } else { // We are the child $childPid = posix_getpid(); doDomStuff($singleHref); exit(0); } } foreach ($pids as $pid) { pcntl_waitpid($pid, $status); } // Clear the libxml buffer so it doesn't fill up libxml_clear_errors(); But what I can't figure out is how to build my hrefsArray[] in the master/parent process only and feed it off to the child process. Currently everything I've tried causes loops in the child processes. I.e. my hrefsArray gets built in the master, and in each subsequent child process. I am sure I am going about this all totally wrong, so would greatly appreciate just general nudge in the right direction.

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  • Problem with videos on heroku

    - by mnml
    Hi, I have recently moved my RoR app on the Heroku platform, and almost everything works fine apart from the videos. It works fine when my app runs in local but not on heroku. This is the error log I'm getting, if anyone knows where it can be coming from: Processing VideosController#new (for IP at 2010-03-20 04:32:09) [GET] Session ID: 6abecf60c3369d7c7029e366bb801e08 Parameters: {"artist_id"=>"10", "action"=>"new", "controller"=>"admin/videos"} Rendering within layouts/admin Rendering admin/videos/new ActionView::TemplateError (undefined method `video_file_relative_path' for #<Video:0x2adc9839fe28>) on line #21 of app/views/admin/videos/ _form.rhtml: 18: 19: <p><label for="videos_image_file">Fichier Vidéo SWF</label><br/> 20: <% if @video.video_file %> 21: <%= link_to image_tag(url_for_file_column("video", "video_file", :name => "thumbnail"))+"<br>", {:controller => url_for_file_column("video", "video_file")}, :popup => ['new_window', 'height=200,width=200'] %> 22: <% end %> 23: <%= file_column_field 'video', 'video_file' %> 24: &nbsp;&nbsp;&nbsp; #{RAILS_ROOT}/vendor/rails/activerecord/lib/active_record/base.rb: 1792:in `method_missing' #{RAILS_ROOT}/vendor/plugins/file_column/lib/file_column_helper.rb: 75:in `send' #{RAILS_ROOT}/vendor/plugins/file_column/lib/file_column_helper.rb: 75:in `url_for_file_column' #{RAILS_ROOT}/app/views/admin/videos/_form.rhtml:21:in `_run_rhtml_admin_videos__form' #{RAILS_ROOT}/vendor/rails/actionpack/lib/action_view/base.rb: 314:in `send' #{RAILS_ROOT}/vendor/rails/actionpack/lib/action_view/base.rb: 314:in `compile_and_render_template' #{RAILS_ROOT}/vendor/rails/actionpack/lib/action_view/base.rb: 290:in `render_template' #{RAILS_ROOT}/vendor/rails/actionpack/lib/action_view/base.rb: 249:in `render_file' #{RAILS_ROOT}/vendor/rails/actionpack/lib/action_view/base.rb: 264:in `render' #{RAILS_ROOT}/vendor/rails/actionpack/lib/action_view/partials.rb: 59:in `render_partial' #{RAILS_ROOT}/vendor/rails/actionpack/lib/action_controller/ benchmarking.rb:33:in `benchmark' #{RAILS_ROOT}/vendor/rails/actionpack/lib/action_view/partials.rb: 58:in `render_partial' #{RAILS_ROOT}/vendor/rails/actionpack/lib/action_view/base.rb: 276:in `render' #{RAILS_ROOT}/app/views/admin/videos/new.rhtml:4:in `_run_rhtml_admin_videos_new' #{RAILS_ROOT}/vendor/rails/actionpack/lib/action_view/base.rb: 314:in `send' #{RAILS_ROOT}/vendor/rails/actionpack/lib/action_view/base.rb: 314:in `compile_and_render_template' #{RAILS_ROOT}/vendor/rails/actionpack/lib/action_view/base.rb: 290:in `render_template' #{RAILS_ROOT}/vendor/rails/actionpack/lib/action_view/base.rb: 249:in `render_file' #{RAILS_ROOT}/vendor/rails/actionpack/lib/action_controller/ base.rb:699:in `render_file' #{RAILS_ROOT}/vendor/rails/actionpack/lib/action_controller/ base.rb:621:in `render_with_no_layout' #{RAILS_ROOT}/vendor/rails/actionpack/lib/action_controller/ layout.rb:243:in `render_without_benchmark' #{RAILS_ROOT}/vendor/rails/actionpack/lib/action_controller/ benchmarking.rb:53:in `render' /usr/local/lib/ruby/1.8/benchmark.rb:293:in `measure' #{RAILS_ROOT}/vendor/rails/actionpack/lib/action_controller/ benchmarking.rb:53:in `render' #{RAILS_ROOT}/vendor/rails/actionpack/lib/action_controller/ base.rb:911:in `perform_action_without_filters' #{RAILS_ROOT}/vendor/rails/actionpack/lib/action_controller/ filters.rb:368:in `perform_action_without_benchmark' #{RAILS_ROOT}/vendor/rails/actionpack/lib/action_controller/ benchmarking.rb:69:in `perform_action_without_rescue' /usr/local/lib/ruby/1.8/benchmark.rb:293:in `measure' #{RAILS_ROOT}/vendor/rails/actionpack/lib/action_controller/ benchmarking.rb:69:in `perform_action_without_rescue' #{RAILS_ROOT}/vendor/rails/actionpack/lib/action_controller/ rescue.rb:82:in `perform_action' #{RAILS_ROOT}/vendor/rails/actionpack/lib/action_controller/ base.rb:381:in `send' #{RAILS_ROOT}/vendor/rails/actionpack/lib/action_controller/ base.rb:381:in `process_without_filters' #{RAILS_ROOT}/vendor/rails/actionpack/lib/action_controller/ filters.rb:377:in `process_without_session_management_support' #{RAILS_ROOT}/vendor/rails/actionpack/lib/action_controller/ session_management.rb:117:in `process' #{RAILS_ROOT}/vendor/rails/railties/lib/dispatcher.rb:38:in `dispatch' /usr/local/lib/ruby/gems/1.8/gems/thin-1.0.1/lib/rack/adapter/ rails.rb:60:in `serve_rails' /usr/local/lib/ruby/gems/1.8/gems/thin-1.0.1/lib/rack/adapter/ rails.rb:80:in `call' /home/heroku_rack/lib/static_assets.rb:9:in `call' /home/heroku_rack/lib/last_access.rb:25:in `call' /usr/local/lib/ruby/gems/1.8/gems/rack-1.0.1/lib/rack/urlmap.rb: 46:in `call' /usr/local/lib/ruby/gems/1.8/gems/rack-1.0.1/lib/rack/urlmap.rb: 40:in `each' /usr/local/lib/ruby/gems/1.8/gems/rack-1.0.1/lib/rack/urlmap.rb: 40:in `call' /home/heroku_rack/lib/date_header.rb:14:in `call' /usr/local/lib/ruby/gems/1.8/gems/rack-1.0.1/lib/rack/builder.rb: 60:in `call' /usr/local/lib/ruby/gems/1.8/gems/thin-1.0.1/lib/thin/ connection.rb:80:in `pre_process' /usr/local/lib/ruby/gems/1.8/gems/thin-1.0.1/lib/thin/ connection.rb:78:in `catch' /usr/local/lib/ruby/gems/1.8/gems/thin-1.0.1/lib/thin/ connection.rb:78:in `pre_process' /usr/local/lib/ruby/gems/1.8/gems/thin-1.0.1/lib/thin/ connection.rb:57:in `process' /usr/local/lib/ruby/gems/1.8/gems/thin-1.0.1/lib/thin/ connection.rb:42:in `receive_data' /usr/local/lib/ruby/gems/1.8/gems/eventmachine-0.12.6/lib/ eventmachine.rb:240:in `run_machine' /usr/local/lib/ruby/gems/1.8/gems/eventmachine-0.12.6/lib/ eventmachine.rb:240:in `run' /usr/local/lib/ruby/gems/1.8/gems/thin-1.0.1/lib/thin/backends/ base.rb:57:in `start' /usr/local/lib/ruby/gems/1.8/gems/thin-1.0.1/lib/thin/server.rb: 150:in `start' /usr/local/lib/ruby/gems/1.8/gems/thin-1.0.1/lib/thin/controllers/ controller.rb:80:in `start' /usr/local/lib/ruby/gems/1.8/gems/thin-1.0.1/lib/thin/runner.rb: 173:in `send' /usr/local/lib/ruby/gems/1.8/gems/thin-1.0.1/lib/thin/runner.rb: 173:in `run_command' /usr/local/lib/ruby/gems/1.8/gems/thin-1.0.1/lib/thin/runner.rb: 139:in `run!' /usr/local/lib/ruby/gems/1.8/gems/thin-1.0.1/bin/thin:6 /usr/local/bin/thin:20:in `load' /usr/local/bin/thin:20 Thanks

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  • Qt C++ signals and slots did not fire

    - by Xegara
    I have programmed Qt a couple of times already and I really like the signals and slots feature. But now, I guess I'm having a problem when a signal is emitted from one thread, the corresponding slot from another thread is not fired. The connection was made in the main program. This is also my first time to use Qt for ROS which uses CMake. The signal fired by the QThread triggered their corresponding slots but the emitted signal of my class UserInput did not trigger the slot in tflistener where it supposed to. I have tried everything I can. Any help? The code is provided below. Main.cpp #include <QCoreApplication> #include <QThread> #include "userinput.h" #include "tfcompleter.h" int main(int argc, char** argv) { QCoreApplication app(argc, argv); QThread *thread1 = new QThread(); QThread *thread2 = new QThread(); UserInput *input1 = new UserInput(); TfCompleter *completer = new TfCompleter(); QObject::connect(input1, SIGNAL(togglePause2()), completer, SLOT(toggle())); QObject::connect(thread1, SIGNAL(started()), completer, SLOT(startCounting())); QObject::connect(thread2, SIGNAL(started()), input1, SLOT(start())); completer->moveToThread(thread1); input1->moveToThread(thread2); thread1->start(); thread2->start(); app.exec(); return 0; } What I want to do is.. There are two seperate threads. One thread is for the user input. When the user enters [space], the thread emits a signal to toggle the boolean member field of the other thread. The other thread 's task is to just continue its process if the user wants it to run, otherwise, the user does not want it to run. I wanted to grant the user to toggle the processing anytime that he wants, that's why I decided to bring them into seperate threads. The following codes are the tflistener and userinput. tfcompleter.h #ifndef TFCOMPLETER_H #define TFCOMPLETER_H #include <QObject> #include <QtCore> class TfCompleter : public QObject { Q_OBJECT private: bool isCount; public Q_SLOTS: void toggle(); void startCounting(); }; #endif tflistener.cpp #include "tfcompleter.h" #include <iostream> void TfCompleter::startCounting() { static uint i = 0; while(true) { if(isCount) std::cout << i++ << std::endl; } } void TfCompleter::toggle() { // isCount = ~isCount; std::cout << "isCount " << std::endl; } UserInput.h #ifndef USERINPUT_H #define USERINPUT_H #include <QObject> #include <QtCore> class UserInput : public QObject { Q_OBJECT public Q_SLOTS: void start(); // Waits for the keypress from the user and emits the corresponding signal. public: Q_SIGNALS: void togglePause2(); }; #endif UserInput.cpp #include "userinput.h" #include <iostream> #include <cstdio> // Implementation of getch #include <termios.h> #include <unistd.h> /* reads from keypress, doesn't echo */ int getch(void) { struct termios oldattr, newattr; int ch; tcgetattr( STDIN_FILENO, &oldattr ); newattr = oldattr; newattr.c_lflag &= ~( ICANON | ECHO ); tcsetattr( STDIN_FILENO, TCSANOW, &newattr ); ch = getchar(); tcsetattr( STDIN_FILENO, TCSANOW, &oldattr ); return ch; } void UserInput::start() { char c = 0; while (true) { c = getch(); if (c == ' ') { Q_EMIT togglePause2(); std::cout << "SPACE" << std::endl; } c = 0; } } Here is the CMakeLists.txt. I just placed it here also since I don't know maybe the CMake has also a factor here. CMakeLists.txt ############################################################################## # CMake ############################################################################## cmake_minimum_required(VERSION 2.4.6) ############################################################################## # Ros Initialisation ############################################################################## include($ENV{ROS_ROOT}/core/rosbuild/rosbuild.cmake) rosbuild_init() set(CMAKE_AUTOMOC ON) #set the default path for built executables to the "bin" directory set(EXECUTABLE_OUTPUT_PATH ${PROJECT_SOURCE_DIR}/bin) #set the default path for built libraries to the "lib" directory set(LIBRARY_OUTPUT_PATH ${PROJECT_SOURCE_DIR}/lib) # Set the build type. Options are: # Coverage : w/ debug symbols, w/o optimization, w/ code-coverage # Debug : w/ debug symbols, w/o optimization # Release : w/o debug symbols, w/ optimization # RelWithDebInfo : w/ debug symbols, w/ optimization # MinSizeRel : w/o debug symbols, w/ optimization, stripped binaries #set(ROS_BUILD_TYPE Debug) ############################################################################## # Qt Environment ############################################################################## # Could use this, but qt-ros would need an updated deb, instead we'll move to catkin # rosbuild_include(qt_build qt-ros) rosbuild_find_ros_package(qt_build) include(${qt_build_PACKAGE_PATH}/qt-ros.cmake) rosbuild_prepare_qt4(QtCore) # Add the appropriate components to the component list here ADD_DEFINITIONS(-DQT_NO_KEYWORDS) ############################################################################## # Sections ############################################################################## #file(GLOB QT_FORMS RELATIVE ${CMAKE_CURRENT_SOURCE_DIR} ui/*.ui) #file(GLOB QT_RESOURCES RELATIVE ${CMAKE_CURRENT_SOURCE_DIR} resources/*.qrc) file(GLOB_RECURSE QT_MOC RELATIVE ${CMAKE_CURRENT_SOURCE_DIR} FOLLOW_SYMLINKS include/rgbdslam_client/*.hpp) #QT4_ADD_RESOURCES(QT_RESOURCES_CPP ${QT_RESOURCES}) #QT4_WRAP_UI(QT_FORMS_HPP ${QT_FORMS}) QT4_WRAP_CPP(QT_MOC_HPP ${QT_MOC}) ############################################################################## # Sources ############################################################################## file(GLOB_RECURSE QT_SOURCES RELATIVE ${CMAKE_CURRENT_SOURCE_DIR} FOLLOW_SYMLINKS src/*.cpp) ############################################################################## # Binaries ############################################################################## rosbuild_add_executable(rgbdslam_client ${QT_SOURCES} ${QT_MOC_HPP}) #rosbuild_add_executable(rgbdslam_client ${QT_SOURCES} ${QT_RESOURCES_CPP} ${QT_FORMS_HPP} ${QT_MOC_HPP}) target_link_libraries(rgbdslam_client ${QT_LIBRARIES})

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  • Is multithreading the right way to go for my case?

    - by Julien Lebosquain
    Hello, I'm currently designing a multi-client / server application. I'm using plain good old sockets because WCF or similar technology is not what I need. Let me explain: it isn't the classical case of a client simply calling a service; all clients can 'interact' with each other by sending a packet to the server, which will then do some action, and possible re-dispatch an answer message to one or more clients. Although doable with WCF, the application will get pretty complex with hundreds of different messages. For each connected client, I'm of course using asynchronous methods to send and receive bytes. I've got the messages fully working, everything's fine. Except that for each line of code I'm writing, my head just burns because of multithreading issues. Since there could be around 200 clients connected at the same time, I chose to go the fully multithreaded way: each received message on a socket is immediately processed on the thread pool thread it was received, not on a single consumer thread. Since each client can interact with other clients, and indirectly with shared objects on the server, I must protect almost every object that is mutable. I first went with a ReaderWriterLockSlim for each resource that must be protected, but quickly noticed that there are more writes overall than reads in the server application, and switched to the well-known Monitor to simplify the code. So far, so good. Each resource is protected, I have helper classes that I must use to get a lock and its protected resource, so I can't use an object without getting a lock. Moreover, each client has its own lock that is entered as soon as a packet is received from its socket. It's done to prevent other clients from making changes to the state of this client while it has some messages being processed, which is something that will happen frequently. Now, I don't just need to protect resources from concurrent accesses. I must keep every client in sync with the server for some collections I have. One tricky part that I'm currently struggling with is the following: I have a collection of clients. Each client has its own unique ID. When a client connects, it must receive the IDs of every connected client, and each one of them must be notified of the newcomer's ID. When a client disconnects, every other client must know it so that its ID is no longer valid for them. Every client must always have, at a given time, the same clients collection as the server so that I can assume that everybody knows everybody. This way if I'm sending a message to client #1 telling "Client #2 has done something", I know that it will always be correctly interpreted: Client 1 will never wonder "but who is Client 2 anyway?". My first attempt for handling the connection of a new client (let's call it X) was this pseudo-code (remember that newClient is already locked here): lock (clients) { foreach (var client in clients) { lock (client) { client.Send("newClient with id X has connected"); } } clients.Add(newClient); newClient.Send("the list of other clients"); } Now imagine that in the same time, another client has sent a packet that translates into a message that must be broadcasted to every connected client, the pseudo-code will be something like this (remember that the current client - let's call it Y - is already locked here): lock (clients) { foreach (var client in clients) { lock (client) { client.Send("something"); } } } An obvious deadlock occurs here: on one thread X is locked, the clients lock has been entered, started looping through the clients, and at one moment must get Y's lock... which is already acquired on the second thread, itself waiting for the clients collection lock to be released! This is not the only case like this in the server application. There are other collections which must be kept in sync with the clients, some properties on a client can be changed by another one, etc. I tried other types of locks, lock-free mechanisms and a bunch of other things. Either there were obvious deadlocks when I'm using too much locks for safety, or obvious race conditions otherwise. When I finally find a good middle point between the two, it usually comes with very subtle race conditions / dead locks and other multi-threading issues... my head hurts very quickly since for any single line of code I'm writing I have to review almost the whole application to ensure everything will behave correctly with any number of threads. So here's my final question: how would you resolve this specific case, the general case, and more importantly: aren't I going the wrong way here? I have little problems with the .NET framework, C#, simple concurrency or algorithms in general. Still, I'm lost here. I know I could use only one thread processing the incoming requests and everything will be fine. However, that won't scale well at all with more clients... But I'm thinking more and more to go this simple way. What do you think? Thanks in advance to you, StackOverflow people which have taken the time to read this huge question. I really had to explain the whole context if I want to get some help.

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