Learning Java Functional Programming

Implementing the visitor pattern

The visitor pattern is useful when you need to use different algorithms to apply to elements of a collection at different times. For example, you may have a collection of components of a train engine. Periodically, maintenance checks will need to be performed against each element. You may also want to occasionally display the status of each component. The collection does not necessarily change, only the operations performed against the components.

The visitor pattern is a way of structuring your data to facilitate the application of different algorithms against the structure without a new algorithm impacting the components.

The structure of the visitor pattern uses a base element interface or collection representing ...