factory-pattern

问题 First of all please forgive me if its a really dumb question, I am just trying to learn this language to its core. I am reading Effective Java and the very first chapter talks about Static factory methods vs. Constructors. Their pros and cons. Few things that are confusing to me are: class of an object returned by static factory method is nonpublic - what exactly does it mean? unlike constructors static factory methods are not required to create a new object each time they are invoked - How

问题 I just read Factory Method. I understand that it provides a way to delegate the instantiation to sub-classes. But I couldn't understand the possible uses in a real-world scenario. Can anyone give one typical example showing how Factory method pattern can be used so that I can relate to what I have read. A problem statement for which factory method pattern is the best solution would be sufficient to make it clear. 回答1: A class implementing factory design pattern works as bridge between

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 I want to write a factory for creating various types of "xxNotification" classes. My concrete "xxNotification" has dependencies registered with AutoFac. I would like to get/resolve instance of "xxNotification" using Autofac. How to do that? public interface INotification { void Notify(string Action, int OrderID); } public class MagentoOrderStateNotification : INotification { private readonly GenericRepository<Order> _orderRepository; private readonly OMRestIntegrationService

问题 I want to write a factory for creating various types of "xxNotification" classes. My concrete "xxNotification" has dependencies registered with AutoFac. I would like to get/resolve instance of "xxNotification" using Autofac. How to do that? public interface INotification { void Notify(string Action, int OrderID); } public class MagentoOrderStateNotification : INotification { private readonly GenericRepository<Order> _orderRepository; private readonly OMRestIntegrationService

问题 I want to write a generic builder class which wraps around any java class and providing setter functions of a specific style. I am not sure if this could be called "dynamically generated functions". When I have a beanish Pojo class i.e. class Pojo { public void setValue(int value) {...} public void setName(String name) {...} } My Maker class should be usable like this: Pojo p = Builder<Pojo>.create(new Pojo()) .setName("Funny") .setValue(123) .build(); As you can see, the work it does should

问题 I've never really looked at the Factory pattern and today decided to take the time and create a quick sample based on this article (http://msdn.microsoft.com/en-us/library/ee817667.aspx), to finally get my head around it. The source code works perfectly arranged in three separate assemblies neatly named Product, Factory and Client. The main benifit (as I understand it) for the Factory pattern is to abstract the instantiation of the "product" class from the "Client" class. So in the provided

问题 Is it possible to have concrete factories create concrete classes with type specific parameters for them, using the abstract factory pattern? Or do the different concrete classes created by their respective concrete factories need to to have the same fields? Ex) In the image below how would you go about to instantiate the WinButton and the OSXButton with different set of arguments given by the client (Application)? 回答1: One of the approaches to address such problems is to send object

问题 In Java, to convert a String to BigInteger you use the constructor new BigInteger(String) but to convert an int/long you use the factory function BigInteger.valueof(long) , why is that? 回答1: There actually is a BigInteger(long) constructor, but it's private. The javadoc on the factory method provides info on why: This "static factory method" is provided in preference to a (long) constructor because it allows for reuse of frequently used BigIntegers. 回答2: @Morad you can find the answer in the

问题 I am trying to make a factory that will have the type passed in, rather then having it hard coded for types. However, when I attempt to add the type to the factory inside of the types .cpp file, I will get a linker error. For example, he is a linker error I am currently getting. 1>RandomClass.obj : error LNK2019: unresolved external symbol "public: short __thiscall TemplatedFactory::AddType(char const *)" (??$AddType@VRandomClass@@@TemplatedFactory@@QAEFPBD@Z) referenced in function "void _