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• How to get notified of changes on a read only table? (I.e., Price drop notifications.)

  - by mirthlab

  Let's say I have these tables/models: Product - id - last_updated_date - name - price User - id - name Wishlist - id - user_id - product_id The Product table has a few million records and is being updated automatically each night via a data import (inserting into a new table, dropping the old one). I basically have read-only access to that table/model. If a product is on a user's wishlist and the price drops, I'd like to be able to notify that user. What methods can be used to do this? I have a couple of ideas: Keep track of the Product.last_updated_date in the wishlist model and periodically poll the product table to see if it has been updated. This sounds like a horrible/non-scaleable solution. Some sort of Postgres View or Function that triggers when the Product table is updated? I'm new to postgres so I'm not yet sure if this is even possible. Something amazing that you will suggest that I haven't thought of :) Any help in the right direction is greatly appreciated!

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• Java vs C# - AddActionListener vs event subscription

  - by S.O.

  Very simple question from one somewhat new to Java: when adding an event handler (or whatever it is called in Java) to a Control, MUST it be an object? I mean, in C# I can do control.event += System.eventHandler(methodThatHandlesEvent) Sure, that's because we have delegate types in C#, but I was wondering if I can choose which method would be called when an event is raised in Java? I mean, in Java I can have something like control.AddActionListener(objectWhichClassImplementsActionListener) And then I have the stupid actionPerformed method in this class, which is the only method that is called. I know, there are more kinds of listeners, but I can't have a "ActionListenerHandler" class in which I implement several actionPerformed methods that can be assigned to different controls?

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• How to find which method makes my iPhone app slow ?

  - by Stewart Hou

  Currently I am working on a production app. One function acts like the settings.app on iPhone. When the user click a cell of a tableView, as shown below http://www.penguintech.net/images/stackoverflow/1.png It will push another view, which includes a textfield to let user input something. However, on both simulator and device, after the app just loaded, the delay between clicking and showing the second view takes around 2 seconds. Then if user get back to previous view and click again, it will be no delay at all. To detect which method makes the delay, I put a NSLog() in every involved methods, but when I was inspecting the console while running the app, all NSLog() message showed in 0.1 seconds, and then still a delay on the app. Is there any other way to trace the performance footage of a app? The Instruments shows only CPU usage in Mac OS not in iPhone.

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• Using Java method to display HTML code

  - by javArc

  Hey folks, ok so this is my problem, I need to display HTML code in a jsp, which wouldn't be a problem, except a requirement for this project is that we place all the code in a public class file and have seperate methods for each chunk(header, sidebar footer, etc). Now here's where i'm confused: "Your method should take the PrintWriter as a parameter to print out each line of HTML, and should have a return type of void" What does that mean? How do I pass the PrintWriter into a method? Does this make sense to anyone?

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• C# + Format TimeSpan

  - by Villager

  Hello, I am trying to format a TimeSpan element in the format of "[minutes]:[seconds]". In this format, 2 minutes and 8 seconds would look like "02:08". I have tried a variety of options with String.Format and the ToString methods, but I get a FormatException. This is what I'm currently trying: DateTime startTime = DateTime.Now; // Do Stuff TimeSpan duration = DateTime.Now.Subtract(startTime); Console.WriteLine("[paragraph of information] Total Duration: " + duration.ToString("mm:ss")); What am I doing wrong? How do I format a TimeSpan element using my desired format? Thank you

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• Imitating Multiple Inheritance in PHP

  - by fabieno

  I am working on my own MVC framework and found myself stuck. I need the following construction: Controller -- Backend_Controller -- Backend_Crud_Controller -- Frontend_Controller -- Frontend_Crud_Controller Both 'Backend_Crud_Controller' and 'Frontend_Crud_Controller' have the same functionality and thus they should extend another class named 'Base_Crud_Controller', the only difference comes from the 'Backend/Frontend' Controllers which implement different mechanisms. Basically they should inherit both classes but my problem is that 'Backend/Frontend' controller doesn't necessarily extend 'Base_Crud_Controller'. I know multiple inheritance doesn't exist in PHP but I am looking for a solution, I choose to refrain Mixins (like in Symfony) as I don't consider that an elegant solution. Interfaces do not suit me as all of these end up as concrete classes that should implement methods.

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• NoMethodError when trying to invoke helper method from Rails controller

  - by John Topley

  I'm getting a NoMethodError when trying to access a method defined in one of my helper modules from one of my controller classes. My Rails application uses the helper class method with the :all symbol as shown below: class ApplicationController < ActionController::Base helper :all . . end My understanding is that this should make all of my controller classes automatically include all of the helper modules within the app/helpers directory, therefore mixing in all of the methods into the controllers. Is this correct? If I explicitly include the helper module within the controller then everything works correctly.

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• c++: strange syntax in what() method of std::exception

  - by Patrick Oscity

  When i am inheriting from std::exception in order to define my own exception type, i need to override the what() method, which has the following signature: virtual const char* what() const throw(); This definitely looks strange to me, like if there were two method names in the signature. Is this some very specific syntax, like with pure virtual methods, e.g.: virtual int method() const = 0; or is this a feature, that could somehow be used in another context, too? And if so, for what could it be used?

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• Can I save my app's state at close time in iPhone OS?

  - by Steve

  I have an app that functions much like an ebook. I have a bunch of textual information in various languages that is accessible through a number of drill down methods. When a user wants to get into where they were reading last, they currently have to navigate through the section and chapter menus to get back to where they were. An ideal solution for this would be to setup a bookmark system, which I am considering. But if I remember correctly, when iPhone OS 4 was announced, they seemed to make a big deal of the added ability to save the state of an app. Does that mean that someone using my reader app would be able to just exit right out, do whatever, and then when they came back in, it would be the reading screen just as they left it? I don't know much about how to setup a bookmarking system, I suppose it would be worth investigating, but I would probably want to just hold off for iPhone OS 4 if that is indeed what it will be capable of doing. Any thoughts or insights would be appreciated!!

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• How to find Junit tests that are using a given Java method directly or indirectly

  - by IT-Worx

  Assume there are Java project and Junit project in an Eclipse workspace. And All the unit tests are located in the Junit project and dependent on the application Java project. When making changes to a Java method, I need to find the unit tests that are using the method directly or indirectly, so that I can run the corresponding tests locally in my PC before checking into source control. I don't want to run the entire junit project since it takes time. I could use Eclipse call hierarchy to expand caller methods one by one until I find a test method. But for a project including more than 1 million lines of source code, digging down the call hierarchy takes time too. The search scope within call hierarchy view doesn't seem help much. Appreciate any help.

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• How do I run modals windows from code with cocoa?

  - by Leandro

  Hi,everybody I`m trying to run a window as modal directly from the code. My program starts and a main NSWindows is showed.A thread still running to see if the user has a valid distribution. if he doesn't I need to run a modal.I mean, I have no buttons clicked in the interface.I've designed a NSWindow on the interface builder for a password set, and I want to call it only when my validation is not successful. I have tested and realized that these methods which are responsible for modal windows running only work in a IBAction environment. //This doesn't work -(void) showPasswordWindow { [NSApp runModalForWindow:[self window]]; } //this works But its not useful for me =( - (IBAction) passwordWindowButton:(id)sender { [NSApp runModalForWindow:[self window]]; } Please, help this newbie =)

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• Doing a lot of input validation in VB.NET

  - by Andy

  I have a form set up where users can enter their booking for a room at my college. I want to validate the user input to avoid SQL injection (my program uses a MS Access database) and also stop numbers and synbols in their name, etc. I can do the validation fine, but there is to be a lot of validation and then methods executed only if all validation tests come back as true. I did have something like this: If txtName.Text = "" Then frmBookErr.SetError(txtName, "Name field cannot be left blank.") fail = 1 Else frmBookErr.SetError(txtName, "") fail = 0 End If And then check the fail variable, but it obviously gets overridden later in the form if one of the validation tests come back as true. Can anyone provide some input into this? Thanks.

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• assignment makes pointer from integer without a cast

  - by mrblippy

  hi, i am trying to make a linked list and create some methods. but i am getting the error assignment makes pointer from integer without a cast. #include <stdio.h> #include <stdlib.h> #include "students.h" node_ptr create(void) { node_ptr students = (node_ptr) malloc(sizeof(struct node)); students->ID = 0; students->name = NULL; students->next = NULL; return students; } void insert_in_order(int n, node_ptr list) { node_ptr before = list; node_ptr new_node = (node_ptr) malloc(sizeof(struct node)); new_node->ID = n;//error is here i think while(before->next && (before->next->ID < n)) { before = before->next; } new_node->next = before->next; before->next = new_node; }

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• Can you use Javascript to detect a file download window created server side?

  - by Zacho

  I have a jQuery plugin I use to dynamically create and render a form on a default.aspx asp.net page, then submit it. The page it gets submitted to is a pdf.aspx page. The page builds a PDF then uses Response.Write to write the file (application/pdf) to the browser. I use the same method to render XLSX files to the browser as well. It works really great, but I need a callback or some event to tell the button when to stop spinning. This prevents the user from continuously clicking the Excel or PDF buttons. Does anyone know a way to detect the file dialog window when it was not created using javascript? I am also open to other methods of callback from the server side as well.

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• How to crete a Java Iterator that throws IOException

  - by Antonio

  I'd like to implement an iterator that retrieves objects from disk/network. Iterator itr = getRemoteIterator(); while(itr.hasNext()) { Object element = itr.next(); System.out.print(element + " "); } However the problem is that hasNext() and next() methods of the Iterator object does not allow to throw IOException. Is there any other standard interface work around this issue? Desired code is: public interface RemoteIterator<E> { boolean hasNext() throws IOException; E next() throws IOException; void remove(); }

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• wpf get access to other classes

  - by Calvin

  I am currently working on a wpf application. There are some methods in other classes in which I want to trigger to do some work instead of trying to figure out how to rewrite them in. How is it that I can get to those classes? Would I have to for example instantiate the class? If so, once I instantiate it, how would I be able access them. Keep in mind that these classes have abstract classes on top of abstract classes.

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• online payment process in radio button

  - by keils

  hi guys im developing in my own website.every thing works fine.i want to know if i clicks the any one of the radio button that value change correspondingly.can any one please post some code i tried this below code. my website is http:spsmobile.co.uk just check the link in this page u just go to phone unlock and click make payment you will see the radio button named pay delivery methods thanks in adv var total = parseInt($("div.total-text").text().substring(1), 10); $("input[name='rmr']").bind('change', function () { var amount = 0; switch (this.value) { case "1": amount = 3; break; case "2": amount = 5.5; break; case "4": amount = 10; break; } $("div.total-text").text("£" + (total + amount)); }); }); $(document).ready(function () { $('#primary').bind('change', function () { $.ajax({ type: "POST", url: "include/unlock_function.php", data: $(this).is(':checked'), success: function (theresponse) {} } } }; } }:

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• Accessing facebook sdk result Object using .NET 3.5 API?

  - by John K

  Consider the following in .NET 3.5 (using the Bin\Net35\Facebook*.dll assemblies): using Facebook; var app = new FacebookApp(); var result = app.Get("me"); // want to access result properties with no dynamic ... in the absence of the C# 4.0 dynamic keyword this provides only generic object members. How best should I access the facebook properties of this result object? Are there helper or utility methods or stronger types in the facebook C# SDK, or should I use standard .NET reflection techniques?

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• Can we change <input type="file"> style?

  - by learner.php

  I tried to change the HTML form, input type file. Here is my code: HTML, form id = form <input class="upload_file" type="file" id="file" name="file" /> .CSS I tried both: .upload_button{ background: url('../images/upload_btn_bg.png') no-repeat; width: 200px; height: 40px; } #form input[type=file]{ background: url('../images/upload_btn_bg.png') no-repeat; width: 200px; height: 40px; } None of both of those methods works. I did see from some website, like facebook, youtube, google or twitter, they have different style. Wonder how they do it.

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• Qt: QAbstractItemModel and 'const'

  - by Eye of Hell

  Hello. I'm trying to use a QTreeView for a first time, with a QAbstractItemModel. And instantly it's a problem: QAbstractItemModel interface declares methods as 'const', assuming they will not change data. But i want a result of SQL query displayed, and returning data for a record with specified indeq REQUIRES to use QSqlQuery::seek() that is a non-const. Is it any 'official' guideline to use a QAbstractItemModel with data that MUST be changed in order to get number of items, data per item etc? Or i must hack C++ with const casts?

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• Applying transformations to NSBitmapImageRep

  - by Adam

  So ... I have an image loaded into an NSBitmapImageRep object, so I am able to examine the contents of specific pixels via a two dimensional array. Now I want to apply a couple of "transformations" to the image, in preparation for some additional processing. If I was manipulating the image manually, in Photoshop, I would: Rotate the image Crop a portion of it and discard the rest Apply a "threshold" transformation (which essentially converts the image to black and white, based on the threshold value I provide) Resample the image to shrink it down a bit (which, although losing some image quality, will speed up the subsequent processing) (not necessarily in that order) Are there objective C methods available to facilitate these specific image manipulations, with the data in the NSBitmapImageRep object? If so, can someone point me to some good examples?

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• XAML-based applications - Event Naming Conventions for C#

  - by user118190

  For event handling, I am starting to see many coders doing this: XButton.Click += OnXButtonClicked() ... void OnXButtonClicked() { ... } Where did this On_ convention come from? It just doesn't feel right in terms of methods. I am starting to see this as well and am wondering what others thought: XButton.Click += HandleXButtonClick() ... void HandleXButtonClick() { ... } When using intellisense, Visual Studio handles these like so: XButton.Click += XButton_Click; ... void XButton_Click(object sender, RoutedEventArgs e) { ... } I am seeking some advice on these naming conventions and would greatly appreciate some advice.

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• How do I dynamically change the path_to()?

  - by Angela

  I currently have three methods which I want to collapse into one: def send_email(contact,email) end def make_call(contact, call) return link_to "Call", new_contact_call_path(:contact => contact, :call => call, :status => 'called') end def make_letter(contact, letter) return link_to "Letter", new_contact_letter_path(:contact => contact, :letter => letter, :status => 'mailed') end I want to collapse the three into one so that I can just pass the Model as one of the parameters and it will still correctly create the path_to. I am trying to do this with the following, but stuck: def do_event(contact, call_or_email_or_letter) model_name = call_or_email_or_letter.class.name.tableize.singularize link_to "#{model_name.camelize}", new_contact_#{model_name}_path(contact, call_or_email_or_letter)" end

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• Is there a way to set the value of $? in a mock in Ruby?

  - by rleber

  I am testing some scripts that interface with system commands. Their logic depends on the return code of the system commands, i.e. the value of $?. So, as a simplified example, the script might say: def foo(command) output=`#{command}` if $?==0 'succeeded' else 'failed' end end In order to be able to test these methods properly, I would like to be able to stub out the Kernel backquote call, and set $? to an arbitrary value, to see if I get appropriate behavior from the logic in the method after the backquote call. I can't figure out a way to do this. (In case it matters, I'm testing using Test::Unit and Mocha.)

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• What is the difference between the * and the & operators in c programming?

  - by Wesley

  I am just making sure I understand this concept correctly. With the * operator, I make a new variable, which is allocated a place in memory. So as to not unnecessarily duplicate variables and their values, the & operator is used in passing values to methods and such and it actually points to the original instance of the variable, as opposed to making new copies...Is that right? It is obviously a shallow understanding, but I just want to make sure I am not getting them mixed up. Thanks!

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