E - the type of elements held in this deque
Serializable, Cloneable, Iterable<E>, Collection<E>, Deque<E>, Queue<E>
Resizable-array implementation of the
Deque
interface. Array deques have no capacity restrictions; they grow as necessary to support usage. They are not thread-safe; in the absence of external synchronization, they do not support concurrent access by multiple threads. Null elements are prohibited. This class is likely to be faster than
Stack
when used as a stack, and faster than
LinkedList
when used as a queue.
Most ArrayDeque operations run in amortized constant time. Exceptions include remove, removeFirstOccurrence, removeLastOccurrence, contains, iterator.remove(), and the bulk operations, all of which run in linear time.
The iterators returned by this class's iterator method are fail-fast: If the deque is modified at any time after the iterator is created, in any way except through the iterator's own remove method, the iterator will generally throw a ConcurrentModificationException. Thus, in the face of concurrent modification, the iterator fails quickly and cleanly, rather than risking arbitrary, non-deterministic behavior at an undetermined time in the future.
Note that the fail-fast behavior of an iterator cannot be guaranteed as it is, generally speaking, impossible to make any hard guarantees in the presence of unsynchronized concurrent modification. Fail-fast iterators throw ConcurrentModificationException on a best-effort basis. Therefore, it would be wrong to write a program that depended on this exception for its correctness: the fail-fast behavior of iterators should be used only to detect bugs.
This class and its iterator implement all of the optional methods of the Collection and Iterator interfaces.
This class is a member of the Java Collections Framework.
Constructors
Constructs an empty array deque with an initial capacity sufficient to hold 16 elements.
Constructs an empty array deque with an initial capacity sufficient to hold the specified number of elements.
Constructs a deque containing the elements of the specified collection, in the order they are returned by the collection's iterator.
boolean
Inserts the specified element at the end of this deque.
boolean
Adds all of the elements in the specified collection at the end of this deque, as if by calling
addLast(E)
on each one, in the order that they are returned by the collection's iterator.
void
Inserts the specified element at the front of this deque.
void
Inserts the specified element at the end of this deque.
void
Removes all of the elements from this deque.
Returns a copy of this deque.
boolean
Returns true if this deque contains the specified element.
Returns an iterator over the elements in this deque in reverse sequential order.
Retrieves, but does not remove, the head of the queue represented by this deque.
void
Performs the given action for each element of the Iterable until all elements have been processed or the action throws an exception.
Retrieves, but does not remove, the first element of this deque.
Retrieves, but does not remove, the last element of this deque.
boolean
Returns true if this deque contains no elements.
Returns an iterator over the elements in this deque.
boolean
Inserts the specified element at the end of this deque.
boolean
Inserts the specified element at the front of this deque.
boolean
Inserts the specified element at the end of this deque.
Retrieves, but does not remove, the head of the queue represented by this deque, or returns null if this deque is empty.
Retrieves, but does not remove, the first element of this deque, or returns null if this deque is empty.
Retrieves, but does not remove, the last element of this deque, or returns null if this deque is empty.
Retrieves and removes the head of the queue represented by this deque (in other words, the first element of this deque), or returns null if this deque is empty.
Retrieves and removes the first element of this deque, or returns null if this deque is empty.
Retrieves and removes the last element of this deque, or returns null if this deque is empty.
Pops an element from the stack represented by this deque.
void
Pushes an element onto the stack represented by this deque.
Retrieves and removes the head of the queue represented by this deque.
boolean
Removes a single instance of the specified element from this deque.
boolean
Removes all of this collection's elements that are also contained in the specified collection (optional operation).
Retrieves and removes the first element of this deque.
boolean
Removes the first occurrence of the specified element in this deque (when traversing the deque from head to tail).
boolean
Removes all of the elements of this collection that satisfy the given predicate.
Retrieves and removes the last element of this deque.
boolean
Removes the last occurrence of the specified element in this deque (when traversing the deque from head to tail).
boolean
Retains only the elements in this collection that are contained in the specified collection (optional operation).
int
Returns the number of elements in this deque.
Returns an array containing all of the elements in this deque in proper sequence (from first to last element).
<T> T[]
Returns an array containing all of the elements in this deque in proper sequence (from first to last element); the runtime type of the returned array is that of the specified array.
public ArrayDeque()
Constructs an empty array deque with an initial capacity sufficient to hold 16 elements.
public ArrayDeque(int numElements)
Constructs an empty array deque with an initial capacity sufficient to hold the specified number of elements.
numElements - lower bound on initial capacity of the deque
Constructs a deque containing the elements of the specified collection, in the order they are returned by the collection's iterator. (The first element returned by the collection's iterator becomes the first element, or front of the deque.)
c - the collection whose elements are to be placed into the deque
NullPointerException - if the specified collection is null
Inserts the specified element at the front of this deque.
addFirst in interface Deque<E>
e - the element to add
NullPointerException - if the specified element is null
This method is equivalent to add(E).
addLast in interface Deque<E>
e - the element to add
NullPointerException - if the specified element is null
Adds all of the elements in the specified collection at the end of this deque, as if by calling
addLast(E)
on each one, in the order that they are returned by the collection's iterator.
addAll in interface Collection<E>
addAll in interface Deque<E>
addAll in class AbstractCollection<E>
c - the elements to be inserted into this deque
true if this deque changed as a result of the call
NullPointerException - if the specified collection or any of its elements are null
Inserts the specified element at the front of this deque.
offerFirst in interface Deque<E>
e - the element to add
true (as specified by Deque.offerFirst(E))
NullPointerException - if the specified element is null
Inserts the specified element at the end of this deque.
offerLast in interface Deque<E>
e - the element to add
true (as specified by Deque.offerLast(E))
NullPointerException - if the specified element is null
Deque
Retrieves and removes the first element of this deque. This method differs from
pollFirst
only in that it throws an exception if this deque is empty.
removeFirst in interface Deque<E>
NoSuchElementException - if this deque is empty
Deque
Retrieves and removes the last element of this deque. This method differs from
pollLast
only in that it throws an exception if this deque is empty.
removeLast in interface Deque<E>
NoSuchElementException - if this deque is empty
Deque
Retrieves and removes the first element of this deque, or returns null if this deque is empty.
Deque
Retrieves and removes the last element of this deque, or returns null if this deque is empty.
Deque
Retrieves, but does not remove, the first element of this deque. This method differs from
peekFirst
only in that it throws an exception if this deque is empty.
getFirst in interface Deque<E>
NoSuchElementException - if this deque is empty
Deque
Retrieves, but does not remove, the last element of this deque. This method differs from
peekLast
only in that it throws an exception if this deque is empty.
getLast in interface Deque<E>
NoSuchElementException - if this deque is empty
Deque
Retrieves, but does not remove, the first element of this deque, or returns null if this deque is empty.
Deque
Retrieves, but does not remove, the last element of this deque, or returns null if this deque is empty.
Removes the first occurrence of the specified element in this deque (when traversing the deque from head to tail). If the deque does not contain the element, it is unchanged. More formally, removes the first element e such that o.equals(e) (if such an element exists). Returns true if this deque contained the specified element (or equivalently, if this deque changed as a result of the call).
removeFirstOccurrence in interface Deque<E>
o - element to be removed from this deque, if present
true if the deque contained the specified element
Removes the last occurrence of the specified element in this deque (when traversing the deque from head to tail). If the deque does not contain the element, it is unchanged. More formally, removes the last element e such that o.equals(e) (if such an element exists). Returns true if this deque contained the specified element (or equivalently, if this deque changed as a result of the call).
removeLastOccurrence in interface Deque<E>
o - element to be removed from this deque, if present
true if the deque contained the specified element
This method is equivalent to addLast(E).
add in interface Collection<E>
add in interface Deque<E>
add in interface Queue<E>
add in class AbstractCollection<E>
e - the element to add
true (as specified by Collection.add(E))
NullPointerException - if the specified element is null
This method is equivalent to offerLast(E).
offer in interface Deque<E>
offer in interface Queue<E>
e - the element to add
true (as specified by Queue.offer(E))
NullPointerException - if the specified element is null
Retrieves and removes the head of the queue represented by this deque. This method differs from
poll()
only in that it throws an exception if this deque is empty.
This method is equivalent to removeFirst().
Retrieves and removes the head of the queue represented by this deque (in other words, the first element of this deque), or returns
null
if this deque is empty.
This method is equivalent to pollFirst().
Retrieves, but does not remove, the head of the queue represented by this deque. This method differs from
peek
only in that it throws an exception if this deque is empty.
This method is equivalent to getFirst().
Retrieves, but does not remove, the head of the queue represented by this deque, or returns
null
if this deque is empty.
This method is equivalent to peekFirst().
This method is equivalent to addFirst(E).
push in interface Deque<E>
e - the element to push
NullPointerException - if the specified element is null
This method is equivalent to removeFirst().
pop in interface Deque<E>
NoSuchElementException - if this deque is empty
public int size()
Returns the number of elements in this deque.
public boolean isEmpty()
Returns true if this deque contains no elements.
isEmpty in interface Collection<E>
isEmpty in class AbstractCollection<E>
true if this deque contains no elements
Returns an iterator over the elements in this deque. The elements will be ordered from first (head) to last (tail). This is the same order that elements would be dequeued (via successive calls to
remove()
or popped (via successive calls to
pop()
).
Deque
Returns an iterator over the elements in this deque in reverse sequential order. The elements will be returned in order from last (tail) to first (head).
descendingIterator in interface Deque<E>
spliterator in interface Collection<E>
spliterator in interface Iterable<E>
Spliterator over the elements in this deque
Iterable
Performs the given action for each element of the
Iterable
until all elements have been processed or the action throws an exception. Actions are performed in the order of iteration, if that order is specified. Exceptions thrown by the action are relayed to the caller.
The behavior of this method is unspecified if the action performs side-effects that modify the underlying source of elements, unless an overriding class has specified a concurrent modification policy.
forEach in interface Iterable<E>
action - The action to be performed for each element
NullPointerException - if the specified action is null
Removes all of the elements of this collection that satisfy the given predicate. Errors or runtime exceptions thrown during iteration or by the predicate are relayed to the caller.
removeIf in interface Collection<E>
filter - a predicate which returns true for elements to be removed
true if any elements were removed
NullPointerException - if the specified filter is null
Removes all of this collection's elements that are also contained in the specified collection (optional operation). After this call returns, this collection will contain no elements in common with the specified collection.
removeAll in interface Collection<E>
removeAll in class AbstractCollection<E>
c - collection containing elements to be removed from this collection
true if this collection changed as a result of the call
NullPointerException - if this collection contains one or more null elements and the specified collection does not support null elements (optional), or if the specified collection is null
Retains only the elements in this collection that are contained in the specified collection (optional operation). In other words, removes from this collection all of its elements that are not contained in the specified collection.
retainAll in interface Collection<E>
retainAll in class AbstractCollection<E>
c - collection containing elements to be retained in this collection
true if this collection changed as a result of the call
NullPointerException - if this collection contains one or more null elements and the specified collection does not permit null elements (optional), or if the specified collection is null
Returns true if this deque contains the specified element. More formally, returns true if and only if this deque contains at least one element e such that o.equals(e).
contains in interface Collection<E>
contains in interface Deque<E>
contains in class AbstractCollection<E>
o - object to be checked for containment in this deque
true if this deque contains the specified element
Removes a single instance of the specified element from this deque. If the deque does not contain the element, it is unchanged. More formally, removes the first element
e
such that
o.equals(e)
(if such an element exists). Returns
true
if this deque contained the specified element (or equivalently, if this deque changed as a result of the call).
This method is equivalent to removeFirstOccurrence(Object).
remove in interface Collection<E>
remove in interface Deque<E>
remove in class AbstractCollection<E>
o - element to be removed from this deque, if present
true if this deque contained the specified element
public void clear()
Removes all of the elements from this deque. The deque will be empty after this call returns.
clear in interface Collection<E>
clear in class AbstractCollection<E>
Returns an array containing all of the elements in this deque in proper sequence (from first to last element).
The returned array will be "safe" in that no references to it are maintained by this deque. (In other words, this method must allocate a new array). The caller is thus free to modify the returned array.
This method acts as bridge between array-based and collection-based APIs.
toArray in interface Collection<E>
toArray in class AbstractCollection<E>
public <T> T[] toArray(T[] a)
Returns an array containing all of the elements in this deque in proper sequence (from first to last element); the runtime type of the returned array is that of the specified array. If the deque fits in the specified array, it is returned therein. Otherwise, a new array is allocated with the runtime type of the specified array and the size of this deque.
If this deque fits in the specified array with room to spare (i.e., the array has more elements than this deque), the element in the array immediately following the end of the deque is set to null.
Like the toArray() method, this method acts as bridge between array-based and collection-based APIs. Further, this method allows precise control over the runtime type of the output array, and may, under certain circumstances, be used to save allocation costs.
Suppose x is a deque known to contain only strings. The following code can be used to dump the deque into a newly allocated array of String:
String[] y = x.toArray(new String[0]);
Note that
toArray(new Object[0])
is identical in function to
toArray()
.
toArray in interface Collection<E>
toArray in class AbstractCollection<E>
T - the component type of the array to contain the collection
a - the array into which the elements of the deque are to be stored, if it is big enough; otherwise, a new array of the same runtime type is allocated for this purpose
ArrayStoreException - if the runtime type of the specified array is not a supertype of the runtime type of every element in this deque
NullPointerException - if the specified array is null
Returns a copy of this deque.
RetroSearch is an open source project built by @garambo | Open a GitHub Issue
Search and Browse the WWW like it's 1997 | Search results from DuckDuckGo
HTML:
3.2
| Encoding:
UTF-8
| Version:
0.7.4