inner-classes

问题 I am trying to include raw JSON inside a Java object when the object is (de)serialized using Jackson. In order to test this functionality, I wrote the following test: public static class Pojo { public String foo; @JsonRawValue public String bar; } @Test public void test() throws JsonGenerationException, JsonMappingException, IOException { String foo = "one"; String bar = "{\"A\":false}"; Pojo pojo = new Pojo(); pojo.foo = foo; pojo.bar = bar; String json = "{\"foo\":\"" + foo + "\",\"bar\":"

问题 I want a static inner class that can't be instantiated even by the external class. Right now I just have a documentation that says "Please don't instantiate this object". Can I give a better signal? 回答1: I want a static inner class that can't be instantiated even by the external class. I assume that "external class" really means the enclosing class. If you don't want to restrict the enclosing class, then making the only constructor of the inner class private will have the desired effect. If

问题 I'm familiar that all local variables will be stored inside stack memory and objects and static variables will be stored in heap. But then when I came across the following code which confuses me. public class Outer { private int a =10; public void outerMethod() { int x = 30; class Inner { private int b = 20; public void innerMethod() { System.out.println("The Value of a is: "+a); System.out.println("The Value of b is: "+b); System.out.println("The Value of x is: "+x); } }; Inner inner = new

问题 I don't understand this: OnGlobalLayoutListener listener = new OnGlobalLayoutListener() { @Override public void onGlobalLayout() { System.out.println("I am override a method"); } public void hello(){ System.out.println("This is a new method"); } }; //listener.hello(); Why I cannot do it? Without this I can do it: new OnGlobalLayoutListener() { @Override public void onGlobalLayout() { System.out.println("I am override a method"); } public void hello(){ System.out.println("This is a new method"

问题 I have encountered a virtual method in a nested class. ##classone.h class ClassOne: { public: class InnerClass{ public: virtual void method1(); ... ##classone.cpp void ClassOne::InnerClass::method1() { ... } I am subclassing ClassOne and need to extend method1() . What need's to be done with the nested class in that situation? What I tried ##subclassone.h class SubClassOne: public ClassOne{ public: virtual void method1(); ##subclassone.cpp void SubClassOne::InnerClass::method1() { ##New

问题 This question already has answers here : Closed 7 years ago . Possible Duplicate: Cannot refer to a non-final variable inside an inner class defined in a different method I'm just experimenting and have a question. Why is this acceptable when I am accessing a non-final class variable from an anonymous inner class: static JLabel e = new JLabel(""); public static void main(String[] args) { JButton b = new JButton("ok"); b.addActionListener(new ActionListener() { @Override public void

问题 If a set of inner classes are the only implementations (subclasses) of their outer abstract containing class, how does one instantiate them? abstract class A { inner class A1 : A() inner class A2 : A() } In other words, what is the syntax to construct an instance of A1 or A2 ? EDIT: ... outside the body of class A. 回答1: Are you looking for this? abstract class A { fun doSome() { // OK val a1 = A1() val a2 = A2() } inner class A1 : A() inner class A2 : A() } I think you probably want to

问题 template<typename IPC_TYPE> class Poller { private: public: struct Event { std::shared_ptr<IPC> ipc; enum Status { NONE = 0, POLLIN = 1, POLLHUP = 2, MessageArrival = 3 }status; }; //block wait Event wait(size_t max_wait_time = 50); }; template<typename IPC_TYPE> Poller<IPC_TYPE>::Event Poller<IPC_TYPE>::wait(size_t max_wait_time = 50) { Event e; return Event(); } I define a class template Poller and also a nested class Event , I am writing a member function of Poller which return a Event

问题 I'm trying to build a templated C++ function that accepts, as its argument, a pointer to an object of an inner class. Here is a reduced version of the class structure involved, similar to a typical linked-list or tree class: template <typename T> struct Outer { struct Inner { T val; Inner (T v) : val(v) { } }; Inner* ptr; Outer(T val) { ptr = new Inner(val); } }; I've made them structs to exclude any access control issues and removed some extraneous instance variables. With that class

问题 I'm having issues using a private method inside a private class inside a public class using the reflections api. Here's a simplified code example: public class Outer { private class Inner { private Integer value; private Inner() { this(0); } private Inner(Integer y) { value = y; } private Integer someMethod(Integer x) { return x * x; } } } Again, I want to be able to instantiate an Outer class object then call someMethod from the private Inner class. I've been trying to do this with