static-methods

问题 Closed . This question is opinion-based. It is not currently accepting answers. Want to improve this question? Update the question so it can be answered with facts and citations by editing this post. Closed 3 years ago . I want to create a class where all utility methods will be kept and these methods will be used throughout the app. Problem:1 Is it good to create a singleton class and keep all necessary methods there or should I create a class where all function will be static. Problem:2

问题 Groovy is so powerful I wonder whether there's an easy way to do this. The scenario: I have an abstract class, AbstractSequence . Then I have two (more in reality) subclasses, called say CasedSequence and LowerCaseSequence . Each of these concrete classes has to have an "identity map", i.e. like a Set but where it is possible to extract an element based on functional equality (overriding of equals and hashCode ). So we have: class CasedSequence extends AbstractSequence { static Map

问题 I would like to have a function that loads a file (in this case an OpenGL texture), but only actually loads the file once, and every time it is called after that it just returns what it initially loaded. What would be a good way to do this? Thanks. 回答1: You need some place to store that state. That can be either inside an object or as a static variable. Let's say: class TextureLoader { public: TextureLoader() {} GLuint loadTexture(std::string const & filename){ std::map<std::string, GLuint>:

问题 I have the following class: public class DocketType : Enumeration<DocketType, int, string> { public static DocketType ChangeOver = new DocketType(1, "Changeover"); public static DocketType Withdrawal = new DocketType(2, "Withdrawal"); public static DocketType Installation = new DocketType(3, "Installation"); private DocketType(int docketTypeId, string description) : base(docketTypeId, description) { } } With the following base class: public abstract class Enumeration<TEnum, X, Y> :

问题 I have the following code class ClassA { static String getA() { 'A' } String string ClassA() { println getA() println ClassA.getA() string = getA() } } // Mocking ClassA.metaClass.static.getA = { -> 'B' } ClassA.metaClass.getA = { -> 'B' } assert ClassA.getA() == 'B' def test = new ClassA() assert test.getA() == 'B' assert test.string == 'B' The last assertion assert test.string == 'B' does not pass. So what I understand is that getA() is not replaced only when called from constructor and

问题 John's console application calls my DLL function many times (~15x per sec). I am thinking to put this function as a static method. I know that : It can only access static props and objects. It doesn't need an instance to run the function. But I don't know if these are the only questions which i need to ask myself. Each John's calls to my function is in a new thread that he creates. If there is an error in my function, how will this affect all other calls? Should I make this function a regular

问题 Can I call a static method of another class without using the class name (in the same package)? There are similar questions but all answers there use class names. 回答1: Yes . But , you would need to import it. Specifically , import static . Like, import static com.package.OtherClass.someMethod; Then you can call someMethod(String) like someMethod("Like that"); 回答2: It is possible using static imports, however I would like to caution you against using them. Static imports obfuscate where the

问题 I'm developing an entity-based component system, and I'm trying to assign a certain index to component types: static std::size_t getNextTypeId() { static std::size_t lastTypeIdBitIdx{0}; ++lastTypeIdBitIdx; // This line produces the output at the end of the question std::cout << lastTypeIdBitIdx << std::endl; return lastTypeIdBitIdx; } // I'm assuming that TypeIdStorage<T1>::bitIdx will always be different // from TypeIdStorage<T2>::bitIdx template<typename T> struct TypeIdStorage { static

问题 I've developed this short test/example code, in order to understand better how static methods work in Python. class TestClass: def __init__(self, size): self.size = size def instance(self): print("regular instance method - with 'self'") @staticmethod def static(): print("static instance method - with @staticmethod") def static_class(): print("static class method") a = TestClass(1000) a.instance() a.static() TestClass.static_class() This code works correctly, it doesn't return any errors. My

问题 I updated my project to Struts2 version 2.3.20 . Now all cases in my JSPs that uses static method access do not work. ie. <s:set var="linkEscaped" value="@org.apache.commons.lang.StringEscapeUtils@escapeHtml(#attr.myObject.link)" /> I already have set in my struts.properties -> struts.ognl.allowStaticMethodAccess=true and tried in struts.xml -> <constant name="struts.ognl.allowStaticMethodAccess" value="true"/> with no success. Does anyone know what has changed and what do I need to do to