getter | 易学教程

In Java is there a performance difference between referencing a field through getter versus through a variable?

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问题 Is there any differences between doing Field field = something.getSomethingElse().getField(); if (field == 0) { //do something } somelist.add(field); versus if (something.getSomethingElse().getField() == 0) { //do something } somelist.add(something.getSomethingElse().getField()); Do references to the field through getters incur a performance penalty or is it the same as referencing an assigned variable? I understand that the variable is just a reference to the memory space, so the getter

Why having const and non-const accessors?

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问题 Why do the STL containers define const and non-const versions of accessors ? What is the advantage of defining const T& at(unsigned int i) const and T& at(unsigned int) and not only the non-const version ? 回答1: Because you wouldn't be able to call at on a const vector object. If you only had the non- const version, the following: const std::vector<int> x(10); x.at(0); would not compile. Having the const version makes this possible, and at the same time prevents you from actually changing what

Public property VS Private property with getter?

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问题 This question has puzzled me for a while. A public property that can be accessed directly or a private property with getter? Which one is better/correct and why? 回答1: Exposing fields directly is considered a bad practice. It is better to keep the field private and only expose the getter and setter. One advantage is that you can choose different access levels for the getter and setter, whereas a field has only a single access level. Another advantage of using getters is that it allows you to

Looking for a short & simple example of getters/setters in C#

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I am having trouble understanding the concept of getters and setters in the C# language . In languages like Objective-C, they seem an integral part of the system, but not so much in C# ( as far as I can tell ). I have read books and articles already, so my question is, to those of you who understand getters & setters in C#, what example would you personally use if you were teaching the concept to a complete beginner ( this would include as few lines of code as possible )? bleepzter I think a bit of code will help illustrate what setters and getters are: public class Foo { private string bar;

How to encapsulate an array in Java

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问题 I'm starting with Java and I'm learning about setters, getters and encapsulation. I have a very simple program, two classes: Container has a private int array ( numArray ) with his setter & getter. Main creates a Container object and uses it in totalArray method. public class Container { private int numArray[]= {0,0,0}; public int[] getNumArray() { return numArray; } public void setNumArray(int index, int value){ numArray[index] = value; } } public class Main { public static void main(String[

How to generate getters and setters in Visual Studio?

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By "generate", I mean auto-generation of the code necessary for a particuliar selected (set of) variable(s). But any more explicit explication or comment on good practice is welcome. Orion Edwards Rather than using ctrl + k , x you can also just type prop and then hit tab twice Visual Studio also has a feature that will generate a Property from a private variable. If you right-click on a variable, in the context menu that pops up click on the "Refactor" item. Then choose encapsulate field. This will create a getter/setter property for a variable. I'm not too big a fan of this technique as it

Java setters and getters

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I have been struggling with setters and getters in java for quite a long time now. For instance, if I want to write a class with some information as name, sex, age etc with appropriate set and get methods. Then in a another class I want to test my set and getters with this as a example: personInfo = myInfo() = new Personinfo("Anna", "female", "17"); How do I do that? I know that I can have a printout like: public void printout() { System.out.printf("Your name is: " + getName() + " and you are a " + getSex()); } This is a simple example to show you how to do it: public class Person { private

Data verifications in Getter/Setter or elsewhere?

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问题 I'm wondering if it's a good idea to make verifications in getters and setters , or elsewhere in the code. This might surprise you be when it comes to optimizations and speeding up the code, I think you should not make verifications in getters and setters, but in the code where you're updating your files or database. Am I wrong? 回答1: Well, one of the reaons why classes usually contain private members with public getters/setters is exactly because they can verify data. If you have a Number

DatabaseException: Found two getters or fields with conflicting case sensitivity

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Every time I try to retrieve data from my database, I get com.google.firebase.database.DatabaseException: Found two getters or fields with conflicting case sensitivity for property: n for any of my fields that are a single letter. Googling this issue gives 0 results and I can find no case incongruities in my code. I don't know if this is a bug in Firebase or if I have to do something special for any fields with names 1 character long. Here is the rest of the error report if it makes a difference (the line of my code which it references is a simple params = dataSnapshot.getValue(Parameters

C# getters, setters declaration [duplicate]

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Possible Duplicates: Why use getters and setters? C# 3.0 Auto-Properties - useful or not? Is there a difference between defining properties the following way - // private, with getter & setter private string fName; public string Name { get { return this.fName } set { this.fName = value } } // define as a Property public string Name { get; set;} As far as I can tell, it only looks like a stylistic preference. Am I missing something? Differences: The second form will only compile with a C# 3 compiler or later The second form doesn't let any code (even in the same class) access the field directly