匿名课程

Question

In Java, it's common to write the following (eg for event handling) in order to make use of the template method pattern:

abstract class SomeAbstractClass {
    public abstract void SomeFunction ();
}

//...

SomeAbstractClass obj = new SomeAbstractClass () {
    public void SomeFunction () { /* implementation */ }
};

In C++, the following compiles:

class SomeAbstractClass {
    virtual void SomeFunction () = 0;
};

// ...

SomeAbstractClass * obj = new ( class : public SomeAbstractClass {
    virtual void SomeFunction () { /* implementation */ }
});

Why don't people do this usually?

Answer 1

Three problems i think occurs with anonymous class

• You cannot write a constructor as class doesn't have a name.
• initializer list inheritance is not allowed.
• capturing value is also difficult, final variable are accessible only.