structure
Interface Queue

All Superinterfaces:

Linear, Structure

All Known Implementing Classes:

AbstractQueue, QueueArray, QueueList, QueueVector

public interface Queue
extends Linear

A first-in, first-out structure. Values are added at the tail, and removed from the head. Used to process values in the order that they appear.

See Also:

Stack

Method Summary

void	add(java.lang.Object value) Add a value to the tail of the queue.
java.lang.Object	dequeue() Remove a value from the head of the queue.
boolean	empty() Returns true iff the queue is empty.
void	enqueue(java.lang.Object value) Add a value to the tail of the queue.
java.lang.Object	get() Fetch the value at the head of the queue.
java.lang.Object	getFirst() Fetch the value at the head of the queue.
java.lang.Object	peek() Fetch the value at the head of the queue.
java.lang.Object	remove() Remove a value form the head of the queue.
int	size() Returns the number of elements in the queue.

Methods inherited from interface structure.Structure

clear, contains, elements, isEmpty, iterator, remove, values

Method Detail

add

void add(java.lang.Object value)

Add a value to the tail of the queue.

Specified by:

add in interface Linear

Specified by:

add in interface Structure

Parameters:

value - The value added.

See Also:

enqueue(java.lang.Object)

Postcondition:

the value is added to the tail of the structure

enqueue

void enqueue(java.lang.Object value)

Add a value to the tail of the queue.

Parameters:

value - The value to be added.

Postcondition:

the value is added to the tail of the structure

remove

java.lang.Object remove()

Remove a value form the head of the queue.

Specified by:

remove in interface Linear

Returns:

The value actually removed.

See Also:

dequeue()

Precondition:

the queue is not empty

Postcondition:

the head of the queue is removed and returned

dequeue

java.lang.Object dequeue()

Remove a value from the head of the queue.

Returns:

The value removed from the queue.

Precondition:

the queue is not empty

Postcondition:

the head of the queue is removed and returned

getFirst

java.lang.Object getFirst()

Fetch the value at the head of the queue.

Returns:

Reference to the first value of the queue.

Precondition:

the queue is not empty

Postcondition:

the element at the head of the queue is returned

get

java.lang.Object get()

Fetch the value at the head of the queue.

Specified by:

get in interface Linear

Returns:

Reference to the first value of the queue.

Precondition:

the queue is not empty

Postcondition:

the element at the head of the queue is returned

peek

java.lang.Object peek()

Fetch the value at the head of the queue.

Returns:

Reference to the first value of the queue.

Precondition:

the queue is not empty

Postcondition:

the element at the head of the queue is returned

empty

boolean empty()

Returns true iff the queue is empty. Provided for compatibility with java.util.Vector.empty.

Specified by:

empty in interface Linear

Returns:

True iff the queue is empty.

Postcondition:

returns true if and only if the queue is empty

size

int size()

Returns the number of elements in the queue.

Specified by:

size in interface Linear

Specified by:

size in interface Structure

Returns:

number of elements in queue.

Postcondition:

returns the number of elements in the queue