void MainWindow::testVisitor()
{
Visitor *pVisitorA = new ConcreteVisitorA();
Visitor *pVisitorB = new ConcreteVisitorB();
Element *pElementA = new ConcreteElementA();
Element *pElementB = new ConcreteElementB();
pElementA->Accept(pVisitorA);
pElementB->Accept(pVisitorB);
}
int main(int argc, const char * argv[]) {
Visitor v;
Element* elementA = new ElementA();
Element* elementB = new ElementB();
elementA->Accept(v);
elementB->Accept(v);
delete elementA;
delete elementB;
return 0;
}
using namespace std; int main(int argc, char* argv[])
{
Visitor* vis = new ConcreteVisitorA();
Element* elm = new ConcreteElementA();
elm->Accept(vis);
delete elm;
delete vis;
return 0;
}
int main(int argc, char *argv[])
{
Visitor *vis = new ConcreteVisitorB();
Element *elm = new ConcreteElementB();
elm->Accept(vis);
system("pause");
return 0;
}
int main()
{
Visitor *pVisitorA = new ConcreateVisitorA();
Element *pElement = new ConcreateElementA();
pElement->Accept(*pVisitorA);
delete pElement;
delete pVisitorA;
return 0;
}
void Writer::Write(const Element& elementRoot, std::ostream& ostr) {
Writer writer(ostr);
elementRoot.Accept(writer);
ostr.flush(); // all done
}
///Visitor 模式则提供了一种解决方案:将更新(变更)封装到一个类中(访问操作)，并 由待更改类提供一个接收接口，则可达到效果。
///Visitor 模式在不破坏类的前提下，为类提供增加新的新操作。Visitor 模式的关键是双分派(Double-Dispatch)的技术。C++语言支持的是单分派。
void VisitorTest() {
Visitor* vis = new ConcreteVisitorA();
Element* elm = new ConcreteElementA();
elm->Accept(vis);
}
void test_visitor()
{
Visitor* pVis = new ConcreteVisitorA();
Element* pElm = new ConcreteElementA();
pElm->Accept(pVis);
}
