Visitor Pattern can be replaced with Callback functions?
- by getit
Is there any significant benefit to using either technique? In case there are variations, the Visitor Pattern I mean is this: http://en.wikipedia.org/wiki/Visitor_pattern
And below is an example of using a delegate to achieve the same effect (at least I think it is the same)
Say there is a collection of nested elements: Schools contain Departments which contain Students
Instead of using the Visitor pattern to perform something on each collection item, why not use a simple callback (Action delegate in C#)
Say something like this
class Department
{
List Students;
}
class School
{
List Departments;
VisitStudents(Action<Student> actionDelegate)
{
foreach(var dep in this.Departments)
{
foreach(var stu in dep.Students)
{
actionDelegate(stu);
}
}
}
}
School A = new School();
...//populate collections
A.Visit((student)=> { ...Do Something with student... });
*EDIT Example with delegate accepting multiple params
Say I wanted to pass both the student and department, I could modify the Action definition like so:
Action
class School
{
List Departments;
VisitStudents(Action<Student, Department> actionDelegate, Action<Department> d2)
{
foreach(var dep in this.Departments)
{
d2(dep); //This performs a different process.
//Using Visitor pattern would avoid having to keep adding new delegates.
//This looks like the main benefit so far
foreach(var stu in dep.Students)
{
actionDelegate(stu, dep);
}
}
}
}
