class

问题 This question already has answers here : Is there something like instanceOf(Class<?> c) in Java? (7 answers) Closed 4 years ago . What's the correct syntax to make this work? public boolean isTypeOf(Class type) { return this instanceof type; } I intend to call it with: foo.isTypeOf(MyClass.class); The method will be overriden, otherwise I would just use instanceof inplace. 回答1: Use Class.isInstance(obj): public boolean isTypeOf(Class type) { return type.isInstance(this); } This method

问题 This question already has answers here : Is there something like instanceOf(Class<?> c) in Java? (7 answers) Closed 4 years ago . What's the correct syntax to make this work? public boolean isTypeOf(Class type) { return this instanceof type; } I intend to call it with: foo.isTypeOf(MyClass.class); The method will be overriden, otherwise I would just use instanceof inplace. 回答1: Use Class.isInstance(obj): public boolean isTypeOf(Class type) { return type.isInstance(this); } This method

问题 I'm trying to use JRuby (through the JSR233 interface included in JRuby 1.5) from a Java application to load a ruby implementation of a Java interface. My sample implementation looks like this: Interface: package some.package; import java.util.List; public interface ScriptDemoIf { int fibonacci(int d); List<String> filterLength(List<String> source, int maxlen); } Ruby Implementation: require 'java' include Java class ScriptDemo java_implements some.package.ScriptDemoIf java_signature 'int

问题 Hi, I have recently started to learn system analysis and design and am having some trouble understanding domain model class diagram (DMCD) association class. As per image, when drawing the DMCD, I'd like to understand if an association class is allowed to contain attributes of the classes it derives from. The Invoice needs to contain the attributes apptNo and svcName. Association class inquiry image: Do I include the attributes as shown in the image? Or do I assume that the Invoice would

问题 Hi, I have recently started to learn system analysis and design and am having some trouble understanding domain model class diagram (DMCD) association class. As per image, when drawing the DMCD, I'd like to understand if an association class is allowed to contain attributes of the classes it derives from. The Invoice needs to contain the attributes apptNo and svcName. Association class inquiry image: Do I include the attributes as shown in the image? Or do I assume that the Invoice would

问题 This question about syntax/syntax capabilities in PHP. Take for example, using variables to store class names when declaring objects: $className= 'myClass'; $obj = new $className; I was wondering if there were some way to do the same with constants. Something along the lines of: define('CLASS_NAME','myClass'); $obj = new {CLASS_NAME}; This doesn't work. Obviously I could just use a variable as an intermediary step, but I was mostly just wondering for edification purposes whether this was a

问题 How can I call a method of class inside a thread? I have a simple method of class and a simple thread... How can I execute de method inside a Thread? Follow the code... #include <iostream> #include<thread> using namespace std; class Airplaine{ public: int vel = 0; void impress(){ cout << "my impress";} // meu método }; int main(){ Airplaine *av1=new Airplaine(); thread first(meu_method_impress()_here); // my method impress inside a thread first.detach(); return 0; } 回答1: To compliment the

问题 I'm learning C++. I know that C++ is a bit more verbose than most other languages, however defining a typedef in a struct/ class declaration and then again in the struct/ class definition got me thinking if there isn't a better or more central place for the typedef where it only has to be defined once, and whether this follows what is thought of as C++ best practices. I couldn't find anything in particular about this on the web. Moving the typedef to a more global place seems inappropriate

问题 This question already has answers here : C++ lambda with captures as a function pointer (8 answers) Closed 4 years ago . UPDATED: (Rephrased) . I'm looking to boost the computation efficiency of my code by make an run-time assignment of a class member function to one of many functions conditional on other class members. One recommended solution uses #include <functional> and function<void()> , as shown in the simple test example: #include <iostream> using namespace std; struct Number { int n;

问题 This question already has answers here : My attempt at value initialization is interpreted as a function declaration, and why doesn't A a(()); solve it? (5 answers) Closed 6 years ago . I have the following three class definitions: class String { public: String() {} String(const char *) {} }; class ClassA { public: ClassA(const String &) {} }; class ClassB { public: ClassB(const ClassA &, const String & = String()) {} void method() {} }; Now suppose I want to create an instance of ClassB :