Java Reference
In-Depth Information
Display 15.25
A Doubly Linked List with an Iterator
(part 1 of 3)
1
import
java.util.NoSuchElementException;
2
public
class
DoublyLinkedList
3{
4
private
class
TwoWayNode
5
{
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private
String item;
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private
TwoWayNode previous;
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private
TwoWayNode next;
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public
TwoWayNode( )
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{
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item =
null
;
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next =
null
;
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previous =
null
;
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}
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public
TwoWayNode(String newItem, TwoWayNode previousNode, TwoWayNode nextNode)
16
{
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item = newItem;
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next = nextNode;
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previous = previousNode;
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}
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}
//End of TwoWayNode inner class
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public
class
DoublyLinkedIterator
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{
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// We do not need a previous node when using a doubly linked list
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private
TwoWayNode position = null;
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public
DoublyLinkedIterator( )
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{
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position = head;
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}
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public
void
restart( )
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{
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position = head;
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}
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public
String next( )
35
{
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if
(!hasNext( ))
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throw
new
IllegalStateException( );
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String toReturn = position.item;
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position = position.next;
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return
toReturn;
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}
