structure
Class DoublyLinkedList

java.lang.Object
  structure.AbstractStructure
      structure.AbstractList
          structure.DoublyLinkedList

All Implemented Interfaces:

List, Structure

public class DoublyLinkedList
extends AbstractList

An implementation of lists that makes use of doubly linked elements. This provided efficient implementation of both head and tail operations.

Constructor Summary

DoublyLinkedList()
Constructs an empty list.

Method Summary

void	add(int i, Object o) Insert value at location.
void	add(Object value) Add a value to head of list.
void	addFirst(Object value) Add a value to head of list.
void	addLast(Object value) Add a value to tail of list.
void	clear() Remove all values from list.
boolean	contains(Object value) Check to see if a value is within list.
Object	get(int i) Get value at location i.
Object	getFirst() Get a copy of first value found in list.
Object	getLast() Get a copy of last value found in list.
int	indexOf(Object value) Determine first location of a value in list.
boolean	isEmpty() Determine if list is empty.
Iterator	iterator() Construct an iterator to traverse list.
int	lastIndexOf(Object value) Determine last location of a value in list.
Object	remove(int i) Remove and return value at location i.
Object	remove(Object value) Remove a value from list.
Object	removeFirst() Remove a value from head of list.
Object	removeLast() Remove a value from tail of list.
Object	set(int i, Object o) Set value stored at location i to object o, returning old value.
int	size() Determine number of elements in list.
String	toString() Construct a string representation of list.

Methods inherited from class structure.AbstractList

get, remove

Methods inherited from class structure.AbstractStructure

elements, hashCode, values

Methods inherited from class java.lang.Object

equals, getClass, notify, notifyAll, wait, wait, wait

Methods inherited from interface structure.Structure

elements, values

Constructor Detail

DoublyLinkedList

public DoublyLinkedList()

Constructs an empty list.

Method Detail

add

public void add(Object value)

Add a value to head of list.

Specified by:

add in interface List

Specified by:

add in interface Structure

Overrides:

add in class AbstractList

Parameters:

value - value to be added.

See Also:

#addToHead

addFirst

public void addFirst(Object value)

Add a value to head of list.

Specified by:

addFirst in interface List

Overrides:

addFirst in class AbstractList

Parameters:

value - value to be added.

removeFirst

public Object removeFirst()

Remove a value from head of list. Value is returned.

Specified by:

removeFirst in interface List

Overrides:

removeFirst in class AbstractList

Returns:

value removed from list.

addLast

public void addLast(Object value)

Add a value to tail of list.

Specified by:

addLast in interface List

Overrides:

addLast in class AbstractList

Parameters:

value - value to be added.

removeLast

public Object removeLast()

Remove a value from tail of list.

Specified by:

removeLast in interface List

Overrides:

removeLast in class AbstractList

Returns:

value removed from list.

getFirst

public Object getFirst()

Get a copy of first value found in list.

Specified by:

getFirst in interface List

Overrides:

getFirst in class AbstractList

Returns:

A reference to first value in list.

getLast

public Object getLast()

Get a copy of last value found in list.

Specified by:

getLast in interface List

Overrides:

getLast in class AbstractList

Returns:

A reference to last value in list.

contains

public boolean contains(Object value)

Check to see if a value is within list.

Specified by:

contains in interface List

Specified by:

contains in interface Structure

Overrides:

contains in class AbstractList

Parameters:

value - A value to be found in list.

Returns:

True if value is in list.

remove

public Object remove(Object value)

Remove a value from list. At most one value is removed. Any duplicates remain. Because comparison is done with "equals," actual value removed is returned for inspection.

Parameters:

value - value to be removed.

Returns:

value actually removed.

size

public int size()

Determine number of elements in list.

Returns:

number of elements found in list.

isEmpty

public boolean isEmpty()

Determine if list is empty.

Specified by:

isEmpty in interface List

Specified by:

isEmpty in interface Structure

Overrides:

isEmpty in class AbstractList

Returns:

True iff list has no values.

clear

public void clear()

Remove all values from list.

get

public Object get(int i)

Get value at location i.

Parameters:

i - position of value to be retrieved.

Returns:

value retrieved from location i (returns null if i invalid)

set

public Object set(int i,
                  Object o)

Set value stored at location i to object o, returning old value.

Parameters:

i - location of entry to be changed.

o - new value

Returns:

former value of ith entry of list.

add

public void add(int i,
                Object o)

Insert value at location.

Parameters:

i - index of this new value

o - value to be stored

remove

public Object remove(int i)

Remove and return value at location i.

Parameters:

i - position of value to be retrieved.

Returns:

value retrieved from location i (returns null if i invalid)

indexOf

public int indexOf(Object value)

Determine first location of a value in list.

Parameters:

value - value sought.

Returns:

index (0 is first element) of value, or -1

lastIndexOf

public int lastIndexOf(Object value)

Determine last location of a value in list.

Parameters:

value - value sought.

Returns:

index (0 is first element) of value, or -1

iterator

public Iterator iterator()

Construct an iterator to traverse list.

Returns:

An iterator that traverses list from head to tail.

See Also:

AbstractIterator, Iterator, Enumeration, Structure.elements()

toString

public String toString()

Construct a string representation of list.

Overrides:

toString in class Object

Returns:

A string representing elements of list.