Summary: Ctors | Methods | Inherited Methods | [Expand All]

public class

ArrayDeque

extends AbstractCollection<E>
implements Serializable Cloneable Deque<E>

java.lang.Object
↳	java.util.AbstractCollection<E>
	↳	java.util.ArrayDeque<E>

Class Overview

An implementation of Deque, backed by an array. ArrayDeques have no size limit, can not contain null element, and they are not thread-safe. All optional operations are supported, and the elements can be any objects.

Summary

Public Constructors
	ArrayDeque() Constructs a new empty instance of ArrayDeque big enough for 16 elements.
	ArrayDeque(int minSize) Constructs a new empty instance of ArrayDeque big enough for specified number of elements.
	ArrayDeque(Collection<? extends E> c) Constructs a new instance of ArrayDeque containing the elements of the specified collection, with the order returned by the collection's iterator.

Public Methods
boolean	add(E e) Inserts the element to the tail of the deque.
void	addFirst(E e) Inserts an element at the head of this deque if it dose not violate size limit immediately.
void	addLast(E e) Inserts an element at the tail of this deque if it dose not violate size limit immediately.
void	clear() Empty the deque.
ArrayDeque<E>	clone() Returns a clone of the deque.
boolean	contains(Object obj) Returns true if the specified element is in the deque.
Iterator<E>	descendingIterator() Returns the iterator in reverse order, from tail to head.
E	element() Gets but does not remove the head element of this deque.
E	getFirst() Gets but not removes the head element of this deque.
E	getLast() Gets but not removes the tail element of this deque.
boolean	isEmpty() Returns true if the deque has no elements.
Iterator<E>	iterator() Returns the iterator of the deque.
boolean	offer(E e) Inserts the element at the tail of the deque.
boolean	offerFirst(E e) Inserts an element at the head of this deque unless it would violate size limit.
boolean	offerLast(E e) Inserts an element at the tail of this deque unless it would violate size limit.
E	peek() Gets but not removes the head element of this deque.
E	peekFirst() Gets but not removes the head element of this deque.
E	peekLast() Gets but not removes the tail element of this deque.
E	poll() Gets and removes the head element of this deque.
E	pollFirst() Gets and removes the head element of this deque.
E	pollLast() Gets and removes the tail element of this deque.
E	pop() Pops the head element of the deque, just same as removeFirst().
void	push(E e) Pushes the element to the deque(at the head of the deque), just same as addFirst(E).
E	remove() Gets and removes the head element of this deque.
boolean	remove(Object obj) Removes the first equivalent element of the specified object.
E	removeFirst() Gets and removes the head element of this deque.
boolean	removeFirstOccurrence(Object obj) Removes the first equivalent element of the specified object.
E	removeLast() Gets and removes the tail element of this deque.
boolean	removeLastOccurrence(Object obj) Removes the last equivalent element of the specified object.
int	size() Returns the size of the deque.
<T> T[]	toArray(T[] array) Returns all the elements in an array from head to tail, and the type of the result array is the type of the argument array.
Object[]	toArray() Returns all the elements in an array from head to tail.

[Expand]

Inherited Methods

From class java.util.AbstractCollection

boolean	add(E object) Attempts to add `object` to the contents of this `Collection` (optional).
boolean	addAll(Collection<? extends E> collection) Attempts to add all of the objects contained in `collection` to the contents of this `Collection` (optional).
void	clear() Removes all elements from this `Collection`, leaving it empty (optional).
boolean	contains(Object object) Tests whether this `Collection` contains the specified object.
boolean	containsAll(Collection<?> collection) Tests whether this `Collection` contains all objects contained in the specified `Collection`.
boolean	isEmpty() Returns if this `Collection` contains no elements.
abstract Iterator<E>	iterator() Returns an instance of `Iterator` that may be used to access the objects contained by this `Collection`.
boolean	remove(Object object) Removes one instance of the specified object from this `Collection` if one is contained (optional).
boolean	removeAll(Collection<?> collection) Removes all occurrences in this `Collection` of each object in the specified `Collection` (optional).
boolean	retainAll(Collection<?> collection) Removes all objects from this `Collection` that are not also found in the `Collection` passed (optional).
abstract int	size() Returns a count of how many objects this `Collection` contains.
<T> T[]	toArray(T[] contents) Returns an array containing all elements contained in this `Collection`.
Object[]	toArray() Returns a new array containing all elements contained in this `Collection`.
String	toString() Returns the string representation of this `Collection`.

From class java.lang.Object

Object	clone() Creates and returns a copy of this `Object`.
boolean	equals(Object o) Compares this instance with the specified object and indicates if they are equal.
void	finalize() Called before the object's memory is reclaimed by the VM.
final Class<? extends Object>	getClass() Returns the unique instance of `Class` that represents this object's class.
int	hashCode() Returns an integer hash code for this object.
final void	notify() Causes a thread which is waiting on this object's monitor (by means of calling one of the `wait()` methods) to be woken up.
final void	notifyAll() Causes all threads which are waiting on this object's monitor (by means of calling one of the `wait()` methods) to be woken up.
String	toString() Returns a string containing a concise, human-readable description of this object.
final void	wait() Causes the calling thread to wait until another thread calls the `notify()` or `notifyAll()` method of this object.
final void	wait(long millis, int nanos) Causes the calling thread to wait until another thread calls the `notify()` or `notifyAll()` method of this object or until the specified timeout expires.
final void	wait(long millis) Causes the calling thread to wait until another thread calls the `notify()` or `notifyAll()` method of this object or until the specified timeout expires.

From interface java.lang.Iterable

From interface java.util.Collection

abstract boolean	add(E object) Attempts to add `object` to the contents of this `Collection` (optional).
abstract boolean	addAll(Collection<? extends E> collection) Attempts to add all of the objects contained in `Collection` to the contents of this `Collection` (optional).
abstract void	clear() Removes all elements from this `Collection`, leaving it empty (optional).
abstract boolean	contains(Object object) Tests whether this `Collection` contains the specified object.
abstract boolean	containsAll(Collection<?> collection) Tests whether this `Collection` contains all objects contained in the specified `Collection`.
abstract boolean	equals(Object object) Compares the argument to the receiver, and returns true if they represent the same object using a class specific comparison.
abstract int	hashCode() Returns an integer hash code for the receiver.
abstract boolean	isEmpty() Returns if this `Collection` contains no elements.
abstract Iterator<E>	iterator() Returns an instance of `Iterator` that may be used to access the objects contained by this `Collection`.
abstract boolean	remove(Object object) Removes one instance of the specified object from this `Collection` if one is contained (optional).
abstract boolean	removeAll(Collection<?> collection) Removes all occurrences in this `Collection` of each object in the specified `Collection` (optional).
abstract boolean	retainAll(Collection<?> collection) Removes all objects from this `Collection` that are not also found in the `Collection` passed (optional).
abstract int	size() Returns a count of how many objects this `Collection` contains.
abstract <T> T[]	toArray(T[] array) Returns an array containing all elements contained in this `Collection`.
abstract Object[]	toArray() Returns a new array containing all elements contained in this `Collection`.

From interface java.util.Deque

abstract void	addFirst(E e) Inserts an element at the head of this deque if it dose not violate size limit immediately.
abstract void	addLast(E e) Inserts an element at the tail of this deque if it dose not violate size limit immediately.
abstract Iterator<E>	descendingIterator() Returns the iterator in reverse order, from tail to head.
abstract E	getFirst() Gets but not removes the head element of this deque.
abstract E	getLast() Gets but not removes the tail element of this deque.
abstract boolean	offerFirst(E e) Inserts an element at the head of this deque unless it would violate size limit.
abstract boolean	offerLast(E e) Inserts an element at the tail of this deque unless it would violate size limit.
abstract E	peekFirst() Gets but not removes the head element of this deque.
abstract E	peekLast() Gets but not removes the tail element of this deque.
abstract E	pollFirst() Gets and removes the head element of this deque.
abstract E	pollLast() Gets and removes the tail element of this deque.
abstract E	pop() Pops the head element of the deque, just same as removeFirst().
abstract void	push(E e) Pushes the element to the deque(at the head of the deque), just same as addFirst(E).
abstract E	removeFirst() Gets and removes the head element of this deque.
abstract boolean	removeFirstOccurrence(Object o) Removes the first equivalent element of the specified object.
abstract E	removeLast() Gets and removes the tail element of this deque.
abstract boolean	removeLastOccurrence(Object o) Removes the last equivalent element of the specified object.

From interface java.util.Queue

Public Constructors

public ArrayDeque ()

Since: API Level 9

Constructs a new empty instance of ArrayDeque big enough for 16 elements.

public ArrayDeque (int minSize)

Since: API Level 9

Constructs a new empty instance of ArrayDeque big enough for specified number of elements.

Parameters

minSize	the smallest size of the ArrayDeque

public ArrayDeque (Collection<? extends E> c)

Since: API Level 9

Constructs a new instance of ArrayDeque containing the elements of the specified collection, with the order returned by the collection's iterator.

Parameters

c	the source of the elements

Throws

NullPointerException	if the collection is null

Public Methods

public boolean add (E e)

Since: API Level 9

Inserts the element to the tail of the deque.

Parameters

e	the element

Returns

true

public void addFirst (E e)

Since: API Level 9

Inserts an element at the head of this deque if it dose not violate size limit immediately. It is better to use offerFirst(E) if a deque is size-limited.

Parameters

e	the element

Throws

NullPointerException	if the element is null

public void addLast (E e)

Since: API Level 9

Inserts an element at the tail of this deque if it dose not violate size limit immediately. It is better to use offerLast(E) if a deque is size-limited.

Parameters

e	the element

Throws

NullPointerException	if the element is null

public void clear ()

Since: API Level 9

Empty the deque.

public ArrayDeque<E> clone ()

Since: API Level 9

Returns a clone of the deque.

Returns

the clone of the deque

public boolean contains (Object obj)

Since: API Level 9

Returns true if the specified element is in the deque.

Parameters

obj	the element

Returns

true if the element is in the deque, false otherwise

public Iterator<E> descendingIterator ()

Since: API Level 9

Returns the iterator in reverse order, from tail to head.

Returns

the reverse order Iterator

public E element ()

Since: API Level 9

Gets but does not remove the head element of this deque. It throws an exception if the deque is empty.

Returns

the head element

Throws

NoSuchElementException	if the deque is empty

public E getFirst ()

Since: API Level 9

Gets but not removes the head element of this deque. This method throws an exception if the deque is empty.

Returns

the head element

Throws

NoSuchElementException	if the deque is empty

public E getLast ()

Since: API Level 9

Gets but not removes the tail element of this deque. This method throws an exception if the deque is empty.

Returns

the tail element

Throws

NoSuchElementException	if the deque is empty

public boolean isEmpty ()

Since: API Level 9

Returns true if the deque has no elements.

Returns

true if the deque has no elements, false otherwise

public Iterator<E> iterator ()

Since: API Level 9

Returns the iterator of the deque. The elements will be ordered from head to tail.

Returns

the iterator

public boolean offer (E e)

Since: API Level 9

Inserts the element at the tail of the deque.

Parameters

e	the element

Returns

true if the operation succeeds or false if it fails.

Throws

NullPointerException	if the element is null

public boolean offerFirst (E e)

Since: API Level 9

Inserts an element at the head of this deque unless it would violate size limit. It is better than the addFirst(E) method in a size-limited deque, because the latter one may fail to add the element only by throwing an exception.

Parameters

e	the element

Returns

true

Throws

NullPointerException	if the element is null

public boolean offerLast (E e)

Since: API Level 9

Inserts an element at the tail of this deque unless it would violate size limit. It is better than the addLast(E) method in a size-limited deque, because the latter one may fail to add the element only by throwing an exception.

Parameters

e	the element

Returns

true if the operation succeeds or false if it fails

Throws

NullPointerException	if the element is null

public E peek ()

Since: API Level 9

Gets but not removes the head element of this deque. This method returns null if the deque is empty.

Returns

the head element or null if the deque is empty

public E peekFirst ()

Since: API Level 9

Gets but not removes the head element of this deque. This method returns null if the deque is empty.

Returns

the head element or null if the deque is empty

public E peekLast ()

Since: API Level 9

Gets but not removes the tail element of this deque. This method returns null if the deque is empty.

Returns

the tail element or null if the deque is empty

public E poll ()

Since: API Level 9

Gets and removes the head element of this deque. This method returns null if the deque is empty.

Returns

the head element or null if the deque is empty

public E pollFirst ()

Since: API Level 9

Gets and removes the head element of this deque. This method returns null if the deque is empty.

Returns

the head element or null if the deque is empty

public E pollLast ()

Since: API Level 9

Gets and removes the tail element of this deque. This method returns null if the deque is empty.

Returns

the tail element or null if the deque is empty

public E pop ()

Since: API Level 9

Pops the head element of the deque, just same as removeFirst().

Returns

the head element

Throws

NoSuchElementException	if the deque is empty

public void push (E e)

Since: API Level 9

Pushes the element to the deque(at the head of the deque), just same as addFirst(E).

Parameters

e	the element to push

Throws

NullPointerException	if the element is null

public E remove ()

Since: API Level 9

Gets and removes the head element of this deque. This method throws an exception if the deque is empty.

Returns

the head element

Throws

NoSuchElementException	if the deque is empty

public boolean remove (Object obj)

Since: API Level 9

Removes the first equivalent element of the specified object. If the deque does not contain the element, it is unchanged and returns false.

Parameters

obj	the element to be removed

Returns

true if the operation succeeds or false if the deque does not contain the element

public E removeFirst ()

Since: API Level 9

Gets and removes the head element of this deque. This method throws an exception if the deque is empty.

Returns

the head element

Throws

NoSuchElementException	if the deque is empty

public boolean removeFirstOccurrence (Object obj)

Since: API Level 9

Removes the first equivalent element of the specified object. If the deque does not contain the element, it is unchanged and returns false.

Parameters

obj	the element to be removed

Returns

true if the operation succeeds or false if the deque does not contain the element

public E removeLast ()

Since: API Level 9

Gets and removes the tail element of this deque. This method throws an exception if the deque is empty.

Returns

the tail element

Throws

NoSuchElementException	if the deque is empty

public boolean removeLastOccurrence (Object obj)

Since: API Level 9

Removes the last equivalent element of the specified object. If the deque does not contain the element, it is unchanged and returns false.

Parameters

obj	the element to be removed

Returns

true if the operation succeeds or false if the deque does not contain the element.

public int size ()

Since: API Level 9

Returns the size of the deque.

Returns

the size of the deque

public T[] toArray (T[] array)

Since: API Level 9

Returns all the elements in an array from head to tail, and the type of the result array is the type of the argument array. If the argument array is big enough, the elements from the deque will be stored in it(elements following the tail of the deque is set to null, if any); otherwise, it will return a new array with the size of the argument array and size of the deque.

Parameters

array	the array stores all the elements from the deque, if it has enough space; otherwise, a new array of the same type and the size of the deque will be used

Returns

the Array of all the elements

Throws

ArrayStoreException	if the type of the argument array is not compatible with every element in the deque
NullPointerException	if the argument array is null

public Object[] toArray ()

Since: API Level 9

Returns all the elements in an array from head to tail. The result is a copy of all the elements.

Returns

the Array of all the elements

Interfaces

Classes

Enums

Exceptions

Errors

ArrayDeque

Class Overview

Summary

Public Constructors

public ArrayDeque ()

public ArrayDeque (int minSize)

Parameters

public ArrayDeque (Collection<? extends E> c)

Parameters

Throws

Public Methods

public boolean add (E e)

Parameters

Returns

See Also

public void addFirst (E e)

Parameters

Throws

See Also

public void addLast (E e)

Parameters

Throws

See Also

public void clear ()

See Also

public ArrayDeque<E> clone ()

Returns

See Also

public boolean contains (Object obj)

Parameters

Returns

See Also

public Iterator<E> descendingIterator ()

Returns

See Also

public E element ()

Returns

Throws

See Also

public E getFirst ()

Returns

Throws

See Also

public E getLast ()

Returns

Throws

See Also

public boolean isEmpty ()

Returns

See Also

public Iterator<E> iterator ()

Returns

See Also

public boolean offer (E e)

Parameters

Returns

Throws

See Also

public boolean offerFirst (E e)

Parameters

Returns

Throws

See Also

public boolean offerLast (E e)

Parameters

Returns

Throws

See Also

public E peek ()

Returns

See Also

public E peekFirst ()

Returns

See Also

public E peekLast ()