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Wrappers and Helpers
For some list operations it is useful to divide the labor into two methods. For example, to print a list backwards in the conventional list format, (3, 2, 1) we can use the printBackwards method to print 3, 2, but we need a separate method to print the parentheses and the first node. We'll call it printBackwardNicely. System.out.print ("("); if (list != null) { Node head = list; Node tail = list.next; printBackward (tail); System.out.print (head); } System.out.println (")"); } Again, it is a good idea to check methods like this to see if they work with special cases like an empty list or a singleton. Elsewhere in the program, when we use this method, we will invoke printBackwardNicely directly and it will invoke printBackward on our behalf. In that sense, printBackwardNicely acts as a wrapper, and it uses printBackward as a helper.
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