| Invoked by a
Tube.copy(TubeCloner) implementation
to copy a reference to another pipe.
This method is for
Tube implementations, not for users.
If the given tube is already copied for this cloning episode,
this method simply returns that reference. Otherwise it copies
a tube, make a note, and returns a copied tube. This additional
step ensures that a graph is cloned isomorphically correctly.
(Think about what happens when a graph is A->B, A->C, B->D, and C->D
if you don't have this step.)
Parameters:
t - The tube to be copied.The cloned tube. Always non-null. |
