structure
Class DoublyLinkedListIterator

java.lang.Object
  |
  +--structure.AbstractIterator
        |
        +--structure.DoublyLinkedListIterator

All Implemented Interfaces:

Enumeration, Iterator

public class DoublyLinkedListIterator

extends AbstractIterator

An iterator for traversing the elements of a doubly linked list. The iterator traverses the list beginning at the head, and heads toward tail. Typical use:

      List l = new DoublyLinkedList();
      // ...list gets built up...
      Iterator li = l.iterator();
      while (li.hasNext())
      {
          System.out.println(li.get());
          li.next();
      }
      li.reset();
      while (li.hasNext())
      { .... }
 

Field Summary

protected DoublyLinkedListElement	current Reference to the current node in the list.
protected DoublyLinkedListElement	head Reference to head of the list.
protected DoublyLinkedListElement	tail Sign of the end of the list.

Constructor Summary

DoublyLinkedListIterator(DoublyLinkedListElement h)
Construct an iterator over a doubly linked list hanging from head.

DoublyLinkedListIterator(DoublyLinkedListElement headDummy, DoublyLinkedListElement tailDummy)

Method Summary

Object	get() Get reference to value that is current.
boolean	hasNext() Determine if there are more elements to be considered.
Object	next() Returns reference to the current element, then increments iterator.
void	reset() Reset the iterator to the head of the list.

Methods inherited from class structure.AbstractIterator

hasMoreElements, nextElement, remove, value

Methods inherited from class java.lang.Object

, clone, equals, finalize, getClass, hashCode, notify, notifyAll, registerNatives, toString, wait, wait, wait

Field Detail

head

protected DoublyLinkedListElement head

Reference to head of the list.

tail

protected DoublyLinkedListElement tail

Sign of the end of the list.

current

protected DoublyLinkedListElement current

Reference to the current node in the list.

Constructor Detail

DoublyLinkedListIterator

public DoublyLinkedListIterator(DoublyLinkedListElement h)

Construct an iterator over a doubly linked list hanging from head.

Parameters:

h - The head of the list to be traversed.

DoublyLinkedListIterator

public DoublyLinkedListIterator(DoublyLinkedListElement headDummy,
                                DoublyLinkedListElement tailDummy)

Method Detail

reset

public void reset()

Reset the iterator to the head of the list.

Overrides:

reset in class AbstractIterator

Postcondition:

resets iterator to list head

hasNext

public boolean hasNext()

Determine if there are more elements to be considered.

Overrides:

hasNext in class AbstractIterator

Postcondition:

returns true iff current element is valid

Returns:

True iff there are more elements to be considered.

next

public Object next()

Returns reference to the current element, then increments iterator.

Overrides:

next in class AbstractIterator

Postcondition:

returns current element and increments iterator

Returns:

Reference to element that was current before increment.

get

public Object get()

Get reference to value that is current.

Overrides:

get in class AbstractIterator

Precondition:

hasNext

Postcondition:

returns current element

Returns:

A reference to the value that is current.