In this case, the visitor pattern could be used to enforce this relationship.

The single-serving visitor pattern should be used when visitors do not need to remain in memory.

"It won't have an impact on changing visitor patterns.

This example adds an (see visitor pattern) method to the class:

For instance, the Visitor pattern need not be implemented in a language that supports multimethods.

For example iterating over a directory structure could be implemented with a visitor pattern.

The visitor pattern also specifies how iteration occurs over the object structure.

In computer programming, the single-serving visitor pattern is a design pattern.

Instead, you could apply the Visitor pattern.

The Visitor pattern encodes a logical operation on the whole hierarchy into a single class containing one method per type.

The visitor pattern requires a programming language that supports single dispatch and method overloading.

We want objects of the two types to co-variantly interact with each other in a double-dispatch using a visitor pattern.

Alternatively, the visitor pattern can be used.

The methods of working around this limitation are analogous; either use the visitor pattern or dynamic cast:

The problem described above can be resolved by simulating double dispatch, for example by using a visitor pattern.

One might consider using visitor pattern, Adapter Pattern, or interface separation instead.

Command pattern: It encapsulates like the visitor pattern one or more functions in an object to present them to a caller.

With this in mind, one ought never to presume the use of agents in the double-dispatch and their application in visitor patterns.

Visitor Pattern using reflection(java).

The framework allows for the generation of an abstract syntax tree which can be traversed using the visitor pattern or evaluated using an interpreter.

Aside from potentially improving separation of concerns, the visitor pattern has an additional advantage over simply calling a polymorphic method: a visitor object can have state.

Iterator pattern: This pattern defines a traversal principle like the visitor pattern without making a type differentiation within the traversed objects.

In a language with only single dispatch, such as Java, the code would probably look something like this (although the visitor pattern can help to solve this problem):

Visitor pattern in UML and in LePUS3 (a Design Description Language)

For example, if a programmer implemented the crosscutting display-update concern using visitors instead, an inter-type declaration using the visitor pattern might look like this in AspectJ: