factory

问题 What is the slickest, most Ruby-like way to have a single constructor return an object of the appropriate type? To be more specific, here's a dummy example: say I have two classes Bike and Car which subclass Vehicle . I want this: Vehicle.new('mountain bike') # returns Bike.new('mountain bike') Vehicle.new('ferrari') # returns Car.new('ferrari') I've proposed a solution below, but it uses allocate which seems way too implementation-heavy. What are some other approaches, or is mine actually ok

问题 What is the slickest, most Ruby-like way to have a single constructor return an object of the appropriate type? To be more specific, here's a dummy example: say I have two classes Bike and Car which subclass Vehicle . I want this: Vehicle.new('mountain bike') # returns Bike.new('mountain bike') Vehicle.new('ferrari') # returns Car.new('ferrari') I've proposed a solution below, but it uses allocate which seems way too implementation-heavy. What are some other approaches, or is mine actually ok

问题 I have this code (the whole story behind it is here: https://codereview.stackexchange.com/questions/28990/fancy-pants-vs-cowboy-coding): public class BeltPrinterFactory : IBeltPrinterFactory { public IBeltPrinter NewBeltPrinter() { switch (printerChoice) { case BeltPrinterType.ZebraQL220: return new ZebraQL220Printer(); case BeltPrinterType.ONiel: return new ONielPrinter(); default: return new ZebraQL220Printer(); } } } ...but have added a "None" to the enum, as many customers will not have

问题 For some context - earlier today I was struggling to figure out how to implement a facade similar to Cache - where I could set a provider (like disk()), but also have a generic fall back provider when not supplied. Now, I got the basic infrastructure working, but I think my implementation is nasty. Having call default() or provider() just stinks. However, there is a concept or something I'm missing to fill in the gaps here. Implementing similar functionality to Cache::disk('x') in Laravel

问题 I am trying to avoid multiple instances of a class being created with the same internal data. I tried an implementation with a separate class for building the MCode but trying to protect the MCode constructor did not work so I have come back to this implementation. I wonder if this is good design or what better solution there may be? public class MCode : IEquatable<MCode> { private readonly static List<MCode> Instances; public AEnum AE { get; } public byte C { get; } public BEnum BE { get; }

问题 I'm having a problem when trying to register my types using their static constructors, with the following factory: public class Factory<T> { public static Factory<T> Instance { get { return _instance; } } private static Factory<T> _instance = new Factory<T>(); private Factory() { } static Factory() { } static Dictionary<string, Type> _registeredType = new Dictionary<string, Type>(); public void Register(string id, T obj) { if (obj.GetType().IsAbstract || obj.GetType().IsInterface) throw new

问题 I need to use factory for fieldset. I know how to do it for form, but how to do it for fieldset? The form code is: namespace Application\Form; use Application\Fieldset\Outline; use Zend\Form\Element; use Zend\Form\Form; class Message extends Form { public function __construct() { parent::__construct('message'); $this->setAttribute('method', 'post'); $this->add([ 'type' => Outline::class, 'options' => [ 'use_as_base_fieldset' => true, ], ]); $this->add([ 'name' => 'submit', 'attributes' => [

问题 Let's say we have a String like this: String string2code = "variable = 'hello';"; How could we convert that String to a piece of code like this?: variable = "hello"; 回答1: GroovyShell is the answer: String string2code = "variable = 'hello'; return variable.toUpperCase()"; def result = new GroovyShell().evaluate string2code assert result == "HELLO" 回答2: If you're into more complex stuff later, you can compile whole classes using GroovyClassLoader . private static Class loadGroovyClass( File

问题 I'm trying to resolve instances by key with SimpleInjector. In my case, the keys are strings which are coming from a configuration file, and I need the factory to return the correct type based on the string. I used a similar solution like the one described in the link above, but changed it slightly, so the instances can provide their own keys. (there will be many classes that implement IFoo , so I'd like to auto-register them with their keys) Here is the complete working example (.NET Core

问题 I'm trying to resolve instances by key with SimpleInjector. In my case, the keys are strings which are coming from a configuration file, and I need the factory to return the correct type based on the string. I used a similar solution like the one described in the link above, but changed it slightly, so the instances can provide their own keys. (there will be many classes that implement IFoo , so I'd like to auto-register them with their keys) Here is the complete working example (.NET Core