The Runabout is an extension of the Java libraries
that adds two-argument multi-dispatch to Java
without changing the language or the VM. It uses
reflection to find visit methods, which are
invoked using dynamically generated and loaded
code. The Runabout does not need a special
compiler or changes to Java's syntax. Dispatch
with the Runabout is fairly fast, typically a
factor of two to ten times slower than double
dispatch. The Runabout is useful since it can help
to make code faster and more readable. For
example, a sequence of instanceof tests is a clear
sign that a Runabout should be used instead.
