原文地址：[url]http://java.dzone.com/articles/visitor-pattern-re-visited[/url]
Understanding the problem
The actual problem is not the naming and horrible API verbosity of visiting code, but the mis-understanding of the pattern. It’s not a pattern that is best suited for visiting large and complex data structures with lots of objects of different types. It[color=red]’s the pattern that is best suited for visiting simple data structures with few different types, but visiting them with hundreds of visitors.[/color] Take files and folders. That’s a simple data structure. You have two types. One can contain the other, both share some properties. Various visitors could be:

CalculateSizeVisitor
FindOldestFileVisitor
DeleteAllVisitor
FindFilesByContentVisitor
ScanForVirusesVisitor
… you name it
I still dislike the naming, but the pattern works perfectly in this paradigm.