constructor-chaining | 易学教程

What is the point of constructor chaining in java and how to combine it with tostring()?

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问题 So i know how to use it, how it works.The question what is the point in real life scenario. Imagine created class without toString() overriding. So what is the point in that class if you can't display it properly ?? And please try not to explain how constructor chaining works or something like that. I know how it works. I want to know does anyone do this in real life because without toString() overriding i don't see the point public class ConstructorChaining { String a; int b; int c; int d;

C# constructor chaining? (How to do it?)

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问题 I know that this is supposedly a super simple question, but I've been struggling with the concept for some time now. My question is, how do you chain constructors in c#? I'm in my first OOP class, so I'm just learning. I don't understand how constructor chaining works or how to implement it, or even why it's better than just doing constructors without chaining. I would appreciate some examples with an explanation. So how do how chain them? I know with two it goes: public SomeClass this: {0}

C# constructor chaining? (How to do it?)

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I want to call only child class constructor in multilevel inheritance?

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问题 class A { public A() { System.out.println("Constructor A"); } } class B extends A { public B() { System.out.println("Constructor B"); } } class C extends B { public C() { System.out.println("Constructor C"); } public static void main(String[] args) { C c = new C(); } } When running the code then it calls all constructor but needs to call only child constructor. output like only print Constructor C 回答1: Like the comments and the other answer already said, this is explicitly impossible . If a

what type of java constructors are these? Constructor chaining?

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问题 These are from the spring amqp samples on github at https://github.com/SpringSource/spring-amqp-samples.git what type of java constructors are these? are they a short hand for getters and setters? public class Quote { public Quote() { this(null, null); } public Quote(Stock stock, String price) { this(stock, price, new Date().getTime()); } as oppossed to this one public class Bicycle { public Bicycle(int startCadence, int startSpeed, int startGear) { gear = startGear; cadence = startCadence;

Constructor chaining with intermediate variables

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问题 I have the following situtation with overloaded constructors which I'm struggling to find a nice solution to. I can't see how to use an intermediate assignment with constructor chaining. The following isn't valid but shows what I want to do public MyThing(IServiceLocator services, int? userId) { // blah.... } public MyThing(IServiceLocator services, string userName) { User user = services.UserService.GetUserByName(userName); int userId = user == null ? null : (int?)user.Id; // call the other

Delphi: Understanding constructors

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问题 i'm looking to understand virtual override overload reintroduce when applied to object constructors. Every time i randomly add keywords until the compiler shuts up - and (after 12 years of developing with Delphi) i'd rather know what i'm doing, rather than trying things randomly. Given a hypothetical set of objects: TComputer = class(TObject) public constructor Create(Cup: Integer); virtual; end; TCellPhone = class(TComputer) public constructor Create(Cup: Integer; Teapot: string); virtual;

Delphi: Understanding constructors

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chaining constructors in Java without throwing exceptions from the default constructor

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问题 I've read this: Can I use throws in constructor? -- which gave me the right idea, and led me to one answer, but was not very explicit. I've also read several others, but could not find my answer. To recap what I've learned for context, essentially, this will not compile... public ExampleClass(String FileName) { this(new FileInputStream(FileName)); } public ExampleClass(FileInputStream FileStream) { DoSomethingToSetupBasedUponFileStream(FileStream); } ...because the FileInputStream constructor

Constructor chaining with intermediate variables

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I have the following situtation with overloaded constructors which I'm struggling to find a nice solution to. I can't see how to use an intermediate assignment with constructor chaining. The following isn't valid but shows what I want to do public MyThing(IServiceLocator services, int? userId) { // blah.... } public MyThing(IServiceLocator services, string userName) { User user = services.UserService.GetUserByName(userName); int userId = user == null ? null : (int?)user.Id; // call the other constructor this(services, userId); } The only way I know to write the above in valid code is public