Interface IQueue<E>

All Known Subinterfaces:

IPriorityQueue<E>

All Known Implementing Classes:

Heap

public interface IQueue<E>

Created by garethhalladay on 10/3/17

Method Summary

Modifier and Type	Method and Description
void	add(E item) Inserts the specified element into this queue, returning true upon success.
void	clear() Removes all of the elements from this queue.
boolean	contains(Object o) Returns true if this queue contains the specified element.
E	element() Retrieves, but does not remove, the head of this queue.
boolean	isEmpty() Returns true if this queue contains no elements.
boolean	offer(E e) Inserts the specified element into this queue if it is possible to do so immediately without violating capacity restrictions.
E	peek() Retrieves, but does not remove, the head of this queue.
E	poll() Retrieves and removes the head of this queue.
E	remove() Retrieves and removes the head of this queue.
int	size() Returns the number of elements in this queue.
String	toString() Returns a string representation of this queue.

Method Detail

add

void add(E item)

Inserts the specified element into this queue, returning true upon success.

This method throws an IllegalStateException if no space is available to hold the new item.

Parameters:

item - the item to add

Throws:

IllegalStateException - if the queue is full

offer

boolean offer(E e)

Inserts the specified element into this queue if it is possible to do so immediately without violating capacity restrictions.

Parameters:

e - the element to add

Returns:

true if the element was added, false if the queue was full

poll

E poll()

Retrieves and removes the head of this queue.

Returns:

the head of this queue, or null if this queue is empty

remove

E remove()

Retrieves and removes the head of this queue. This method differs from poll only in that it throws an exception if this queue is empty.

Returns:

the head of this queue

Throws:

NoSuchElementException - if this queue is empty

peek

E peek()

Retrieves, but does not remove, the head of this queue.

Returns:

the head of this queue, or null if this queue is empty

element

E element()

Retrieves, but does not remove, the head of this queue. This method differs from peek only in that it throws an exception if this queue is empty.

Returns:

the head of this queue

Throws:

NoSuchElementException - if this queue is empty

isEmpty

boolean isEmpty()

Returns true if this queue contains no elements.

Returns:

true if this queue is empty, false otherwise

size

int size()

Returns the number of elements in this queue.

Returns:

the number of elements in the queue

clear

void clear()

Removes all of the elements from this queue. The queue will be empty after this call returns.

toString

String toString()

Returns a string representation of this queue. The string representation consists of a list of the queue's elements in the order they are returned by its iterator, enclosed in square brackets ("[]"). Adjacent elements are separated by the characters ", " (comma and space). Elements are converted to strings as by String.valueOf(Object).

Overrides:

toString in class Object

Returns:

a string representation of this queue

contains

boolean contains(Object o)

Returns true if this queue contains the specified element. More formally, returns true if and only if this queue contains at least one element e such that o.equals(e).

Parameters:

o - object to be checked for containment in this queue

Returns:

true if this queue contains the specified element, false otherwise