structure
Class CircularList

java.lang.Object
  structure.AbstractStructure
      structure.AbstractList
          structure.CircularList

All Implemented Interfaces:

List, Structure

public class CircularList
extends AbstractList

A class implementing a singly linked circular list.

Field Summary

protected int	count Number of elements within circular list.
protected Node	tail A reference to tail of list.

Constructor Summary

CircularList()
Construct an empty circular list.

Method Summary

void	add(int i, java.lang.Object o) Insert value at location.
void	add(java.lang.Object value) Add an element to head of circular list.
void	addFirst(java.lang.Object value) Add an element to head of list.
void	addLast(java.lang.Object value) Add a value to tail of circular list.
void	clear() Remove elements of list.
boolean	contains(java.lang.Object value) Check if a list contains an element.
java.lang.Object	get(int i) Get value at location i.
java.lang.Object	getFirst() Determine if a list is empty.
java.lang.Object	getLast() Peek at last element of list.
int	indexOf(java.lang.Object value) Determine first location of a value in list.
boolean	isEmpty() Determine if a list is empty.
java.util.Iterator	iterator() Construct an iterator over elements of list.
int	lastIndexOf(java.lang.Object value) Determine last location of a value in list.
java.lang.Object	remove(int i) Remove and return value at location i.
java.lang.Object	remove(java.lang.Object value) Remove a value from a list.
java.lang.Object	removeFirst() Remove a value from head of list.
java.lang.Object	removeLast() Remove a value from tail of list.
java.lang.Object	set(int i, java.lang.Object o) Set value stored at location i to object o, returning old value.
int	size() Determine size of list.
java.lang.String	toString() Generate 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

clone, equals, finalize, getClass, notify, notifyAll, wait, wait, wait

Methods inherited from interface structure.Structure

elements, values

Field Detail

tail

protected Node tail

A reference to tail of list. tail points to head.

count

protected int count

Number of elements within circular list.

Constructor Detail

CircularList

public CircularList()

Construct an empty circular list.

Precondition:

constructs a new circular list

Method Detail

add

public void add(java.lang.Object value)

Add an element to head of circular list.

Specified by:

add in interface List

Specified by:

add in interface Structure

Overrides:

add in class AbstractList

Parameters:

value - value to be added to list.

See Also:

AbstractList.addLast(java.lang.Object)

Postcondition:

adds value to beginning of list

addFirst

public void addFirst(java.lang.Object value)

Add an element to head of list.

Specified by:

addFirst in interface List

Overrides:

addFirst in class AbstractList

Parameters:

value - value added to head of list.

Precondition:

value non-null

Postcondition:

adds element to head of list

addLast

public void addLast(java.lang.Object value)

Add a value to tail of circular list.

Specified by:

addLast in interface List

Overrides:

addLast in class AbstractList

Parameters:

value - value to be added.

Precondition:

value non-null

Postcondition:

adds element to tail of list

getFirst

public java.lang.Object getFirst()

Determine if a list is empty.

Specified by:

getFirst in interface List

Overrides:

getFirst in class AbstractList

Returns:

True if there are no elements within list.

Precondition:

!isEmpty()

Postcondition:

returns value at head of list

getLast

public java.lang.Object getLast()

Peek at last element of list.

Specified by:

getLast in interface List

Overrides:

getLast in class AbstractList

Returns:

value of last element of list.

Precondition:

!isEmpty()

Postcondition:

returns value at tail of list

removeFirst

public java.lang.Object removeFirst()

Remove a value from head of list.

Specified by:

removeFirst in interface List

Overrides:

removeFirst in class AbstractList

Returns:

value removed.

Precondition:

!isEmpty()

Postcondition:

returns and removes value from head of list

removeLast

public java.lang.Object removeLast()

Remove a value from tail of list.

Specified by:

removeLast in interface List

Overrides:

removeLast in class AbstractList

Returns:

value removed.

Precondition:

!isEmpty()

Postcondition:

returns and removes value from tail of list

contains

public boolean contains(java.lang.Object value)

Check if a list contains an element.

Specified by:

contains in interface List

Specified by:

contains in interface Structure

Overrides:

contains in class AbstractList

Parameters:

value - value sought.

Returns:

True iff value is within list.

Precondition:

value != null

Postcondition:

returns true if list contains value, else false

remove

public java.lang.Object remove(java.lang.Object value)

Remove a value from a list.

Parameters:

value - value sought.

Returns:

value removed from list.

Precondition:

value != null

Postcondition:

removes and returns element equal to value, or null

size

public int size()

Determine size of list.

Returns:

number of elements in list.

Postcondition:

returns number of elements in list

get

public java.lang.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)

Precondition:

0 <= i < size()

Postcondition:

returns object found at that location

set

public java.lang.Object set(int i,
                            java.lang.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.

Precondition:

0 <= i < size()

Postcondition:

sets ith entry of list to value o, returns old value

add

public void add(int i,
                java.lang.Object o)

Insert value at location.

Parameters:

i - index of this new value

o - value to be stored

Precondition:

0 <= i <= size()

Postcondition:

adds ith entry of list to value o

remove

public java.lang.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)

Precondition:

0 <= i < size()

Postcondition:

removes and returns object found at that location

indexOf

public int indexOf(java.lang.Object value)

Determine first location of a value in list.

Parameters:

value - value sought.

Returns:

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

Precondition:

value is not null

Postcondition:

returns (0-origin) index of value, or -1 if value is not found

lastIndexOf

public int lastIndexOf(java.lang.Object value)

Determine last location of a value in list.

Parameters:

value - value sought.

Returns:

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

Precondition:

value is not null

Postcondition:

returns (0-origin) index of value, or -1 if value is not found

iterator

public java.util.Iterator iterator()

Construct an iterator over elements of list. Elements are traversed from head to tail.

Returns:

iterator associated with list.

See Also:

AbstractIterator, Iterator, Enumeration, Structure.elements()

Postcondition:

returns iterator to traverse list elements

isEmpty

public boolean isEmpty()

Determine if a list is empty.

Specified by:

isEmpty in interface List

Specified by:

isEmpty in interface Structure

Overrides:

isEmpty in class AbstractList

Returns:

True iff list is empty.

Postcondition:

returns true if no elements in list

clear

public void clear()

Remove elements of list.

Postcondition:

removes all elements from list

toString

public java.lang.String toString()

Generate a string representation of list.

Overrides:

toString in class java.lang.Object

Returns:

String representing list.

Postcondition:

returns a string representing list