Java Reference
In-Depth Information
Self-Test Exercises
4. Would it make any difference if we changed the
Node
inner class in Display 15.7
from a private inner class to a public inner class?
5. Keeping the inner class
Node
in Display 15.7 as
private
, what difference would
it make if any of the instance variables or methods in the class
Node
had its access
modifi ers changed from
private
to
public
or package access?
6. Why does the defi nition of the inner class
Node
in Display 15.7 not have
the accessor and mutator methods
getLink
,
setLink
, or other
get
and
set
methods for the link fi elds similar to those in the class defi nition of
Node1
in
Display 15.2 ?
7. Would it be legal to add the following method to the class
LinkedList2
in
Display 15.7 ?
public
Node startNode( )
{
return head;
}
8. Rewrite the defi nition of the class
LinkedList2
in Display 15.7 so that it has
data of a type named
Entry
, which is a public inner class. Objects of type
Entry
have two instance variables defi ned as follows:
private
String item;
private int
count;
This rewritten version of
LinkedList2
will be equivalent to
LinkedList1
in
that it has the same methods doing the same things, and it will hold equivalent
data in its nodes.
EXAMPLE:
A Generic Linked List
Display 15.8 shows a generic linked list with a type parameter
T
for the type of data
stored in a node. This generic linked list has the same methods, coded in basically the
same way, as our previous linked list (Display 15.7), but we used a type parameter for
the type of data in the nodes.
Display 15.10 contains a demonstration program for our generic linked list. The
demonstration program uses the class
Entry
, defined in Display 15.9 , as the type
plugged in for the type parameter
T
. Note that if you want multiple pieces of data in
each node, you simply use a class type that has multiple instance variables and plug in
this class for the type parameter
T
.
