instantiation

问题 I want to construct an object in the stack, using C++. Do you know what is the difference between these to ways of calling the constructor (with and without parenthesis): a) MyClass object ; b) MyClass object() ; I am using MFC and when constructing the global variable for the main app, if I use the latter way, I get an exception, I thought these two ways were equivalent. Thank you guys for any information. 回答1: This is one of those gotchas of C++. MyClass object(); is the way that a function

问题 I'm have some difficulties here, I am unable to successfully call a method which belongs to a ProjectPage model in the ProjectPage controller . I have in my ProjectPage controller: def index @searches = Project.published.financed @project_pages = form_search(params) end And in my ProjectPage model : def form_search(searches) searches = searches.where('amount > ?', params[:price_min]) if check_params(params[:price_min]) @project_pages = ProjectPage.where(:project_id => searches.pluck(:

问题 I'm designing a class that defines a highly complex object with a ton (50+) of mostly optional parameters, many of which would have defaults (eg: $type = 'foo'; $width = '300'; $interactive = false; ). I'm trying to determine the best way to set up the constructor and instance/class variables in order to be able to: make it easy to use the class make it easy to auto-document the class (ie: using phpDocumentor) code this elegantly In light of the above, I don't want to be passing the

问题 Is it ok to instantiate an object in a View before passing it to a partial? <%= render :partial => "trade_new", :locals => {:trade=>Trade.new("e", "b") } %> Or is better to instantiate any objects in the Controller as instance variables: @trade = Trade.new("e", "b") and then pass the instance variable to a partial in the view like this: <%= render :partial => "trade_new", :locals => {:trade => @trade } %> My guess is it's better to instantiate new objects in the controller to avoid

问题 I am creating a google chrome extension which, when activated on a tab, loads some custom code and a few new views into the document of that window. I'd like to use requireJS to load these new modules of code called by the extension. However, I worried about a possible conflict or name collision that might occur if the app/website this extension is called on is already running requireJS, and my calling it from scratch either wipes the sites native require.config or otherwise causes some

问题 In my CakePHP 2 application I have such vendor. I need to create an instance of this vendor class inside my controller class. So I will use that instance inside my controller's different functions. App::import('Vendor', 'fancyVendor', array('file' => 'fancyVendor.php')); class MyController extends AppController { public $fancyVendor; function beforeFilter() { $fancyVendor = new fancyVendor(); $fancyVendor->setValue("12"); } function showMe() { echo $fancyVendor->getValue(); } } Inside my

问题 I am getting RuntimeException Enum types may not be instantiated I don't know why. What I want is to identify a year by an integer value like i have 9 so the year for other Methods is 2006. Code: public class P21Make { enum Catalog { year2005(9),year2006(12),year2007(15),year2008(18), year2009(21),year2010(23),year2011(25),year2012(28), year2013(31),year2014(33),year2015(36),year2016(39), year2017(42),year2018(45),year2019(48),year2020(51); private int id; Catalog(int c){ this.id=c; } }

问题 Netty instantiates a set of request handler classes whenever a new connection is opened. This seems fine for something like a websocket where the connection will stay open for the lifetime of the websocket. When using Netty as an HTTP server which could receive thousands of requests per second this seems like it would be rather taxing on garbage collection. Every single request instantiates several classes (in my case 10 handler classes) and then garbage collects them some milliseconds later.

问题 Netty instantiates a set of request handler classes whenever a new connection is opened. This seems fine for something like a websocket where the connection will stay open for the lifetime of the websocket. When using Netty as an HTTP server which could receive thousands of requests per second this seems like it would be rather taxing on garbage collection. Every single request instantiates several classes (in my case 10 handler classes) and then garbage collects them some milliseconds later.

问题 Netty instantiates a set of request handler classes whenever a new connection is opened. This seems fine for something like a websocket where the connection will stay open for the lifetime of the websocket. When using Netty as an HTTP server which could receive thousands of requests per second this seems like it would be rather taxing on garbage collection. Every single request instantiates several classes (in my case 10 handler classes) and then garbage collects them some milliseconds later.