Class LinkedBlockingDeque<E>
- java.lang.Object
-
- java.util.AbstractCollection<E>
-
- java.util.AbstractQueue<E>
-
- java.util.concurrent.LinkedBlockingDeque<E>
- Type Parameters:
-
E
- the type of elements held in this deque
- All Implemented Interfaces:
-
Serializable
,Iterable<E>
,Collection<E>
,BlockingDeque<E>
,BlockingQueue<E>
,Deque<E>
,Queue<E>
public class LinkedBlockingDeque<E> extends AbstractQueue<E> implements BlockingDeque<E>, Serializable
An optionally-bounded blocking deque based on linked nodes.
The optional capacity bound constructor argument serves as a way to prevent excessive expansion. The capacity, if unspecified, is equal to Integer.MAX_VALUE
. Linked nodes are dynamically created upon each insertion unless this would bring the deque above capacity.
Most operations run in constant time (ignoring time spent blocking). Exceptions include remove
, removeFirstOccurrence
, removeLastOccurrence
, contains
, iterator.remove()
, and the bulk operations, all of which run in linear time.
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.
- Since:
- 1.6
- See Also:
- Serialized Form
Constructor Summary
Constructor | Description |
---|---|
LinkedBlockingDeque() | Creates a |
LinkedBlockingDeque(int capacity) | Creates a |
LinkedBlockingDeque(Collection<? extends E> c) | Creates a |
Method Summary
Modifier and Type | Method | Description |
---|---|---|
boolean | add(E e) | Inserts the specified element at the end of this deque unless it would violate capacity restrictions. |
boolean | addAll(Collection<? extends E> c) | Appends all of the elements in the specified collection to the end of this deque, in the order that they are returned by the specified collection's iterator. |
void | addFirst(E e) | Inserts the specified element at the front of this deque if it is possible to do so immediately without violating capacity restrictions, throwing an |
void | addLast(E e) | Inserts the specified element at the end of this deque if it is possible to do so immediately without violating capacity restrictions, throwing an |
void | clear() | Atomically removes all of the elements from this deque. |
boolean | contains(Object o) | Returns |
Iterator<E> | descendingIterator() | Returns an iterator over the elements in this deque in reverse sequential order. |
int | drainTo(Collection<? super E> c) | Removes all available elements from this queue and adds them to the given collection. |
int | drainTo(Collection<? super E> c,
int maxElements) | Removes at most the given number of available elements from this queue and adds them to the given collection. |
E | element() | Retrieves, but does not remove, the head of the queue represented by this deque. |
void | forEach(Consumer<? super E> action) | Performs the given action for each element of the |
E | getFirst() | Retrieves, but does not remove, the first element of this deque. |
E | getLast() | Retrieves, but does not remove, the last element of this deque. |
Iterator<E> | iterator() | Returns an iterator over the elements in this deque in proper sequence. |
boolean | offer(E e) | Inserts the specified element into the queue represented by this deque (in other words, at the tail of this deque) if it is possible to do so immediately without violating capacity restrictions, returning |
boolean | offer(E e,
long timeout,
TimeUnit unit) | Inserts the specified element into the queue represented by this deque (in other words, at the tail of this deque), waiting up to the specified wait time if necessary for space to become available. |
boolean | offerFirst(E e) | Inserts the specified element at the front of this deque if it is possible to do so immediately without violating capacity restrictions, returning |
boolean | offerFirst(E e,
long timeout,
TimeUnit unit) | Inserts the specified element at the front of this deque, waiting up to the specified wait time if necessary for space to become available. |
boolean | offerLast(E e) | Inserts the specified element at the end of this deque if it is possible to do so immediately without violating capacity restrictions, returning |
boolean | offerLast(E e,
long timeout,
TimeUnit unit) | Inserts the specified element at the end of this deque, waiting up to the specified wait time if necessary for space to become available. |
E | pop() | Pops an element from the stack represented by this deque. |
void | push(E e) | Pushes an element onto the stack represented by this deque (in other words, at the head of this deque) if it is possible to do so immediately without violating capacity restrictions, throwing an |
void | put(E e) | Inserts the specified element into the queue represented by this deque (in other words, at the tail of this deque), waiting if necessary for space to become available. |
void | putFirst(E e) | Inserts the specified element at the front of this deque, waiting if necessary for space to become available. |
void | putLast(E e) | Inserts the specified element at the end of this deque, waiting if necessary for space to become available. |
int | remainingCapacity() | Returns the number of additional elements that this deque can ideally (in the absence of memory or resource constraints) accept without blocking. |
E | remove() | Retrieves and removes the head of the queue represented by this deque. |
boolean | remove(Object o) | Removes the first occurrence of the specified element from this deque. |
boolean | removeAll(Collection<?> c) | Removes all of this collection's elements that are also contained in the specified collection (optional operation). |
E | removeFirst() | Retrieves and removes the first element of this deque. |
boolean | removeIf(Predicate<? super E> filter) | Removes all of the elements of this collection that satisfy the given predicate. |
E | removeLast() | Retrieves and removes the last element of this deque. |
boolean | retainAll(Collection<?> c) | Retains only the elements in this collection that are contained in the specified collection (optional operation). |
int | size() | Returns the number of elements in this deque. |
Spliterator<E> | spliterator() | Returns a |
Object[] | toArray() | Returns an array containing all of the elements in this deque, in proper sequence (from first to last element). |
<T> T[] | toArray(T[] a) | Returns an array containing all of the elements in this deque, in proper sequence; the runtime type of the returned array is that of the specified array. |
Methods declared in class java.util.AbstractCollection
containsAll, isEmpty, toString
Methods declared in class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait
Methods declared in interface java.util.concurrent.BlockingDeque
peek, poll, poll, pollFirst, pollLast, removeFirstOccurrence, removeLastOccurrence, take, takeFirst, takeLast
Methods declared in interface java.util.Collection
containsAll, equals, hashCode, isEmpty, parallelStream, stream, toArray
Methods declared in interface java.util.Deque
peekFirst, peekLast, pollFirst, pollLast
Constructor Detail
LinkedBlockingDeque
public LinkedBlockingDeque()
Creates a LinkedBlockingDeque
with a capacity of Integer.MAX_VALUE
.
LinkedBlockingDeque
public LinkedBlockingDeque(int capacity)
Creates a LinkedBlockingDeque
with the given (fixed) capacity.
- Parameters:
-
capacity
- the capacity of this deque - Throws:
-
IllegalArgumentException
- ifcapacity
is less than 1
LinkedBlockingDeque
public LinkedBlockingDeque(Collection<? extends E> c)
Creates a LinkedBlockingDeque
with a capacity of Integer.MAX_VALUE
, initially containing the elements of the given collection, added in traversal order of the collection's iterator.
- Parameters:
-
c
- the collection of elements to initially contain - Throws:
-
NullPointerException
- if the specified collection or any of its elements are null
Method Detail
addFirst
public void addFirst(E e)
Description copied from interface: BlockingDeque
Inserts the specified element at the front of this deque if it is possible to do so immediately without violating capacity restrictions, throwing an IllegalStateException
if no space is currently available. When using a capacity-restricted deque, it is generally preferable to use offerFirst
.
- Specified by:
-
addFirst
in interfaceBlockingDeque<E>
- Specified by:
-
addFirst
in interfaceDeque<E>
- Parameters:
-
e
- the element to add - Throws:
-
IllegalStateException
- if this deque is full -
NullPointerException
- if the specified element is null
addLast
public void addLast(E e)
Description copied from interface: BlockingDeque
Inserts the specified element at the end of this deque if it is possible to do so immediately without violating capacity restrictions, throwing an IllegalStateException
if no space is currently available. When using a capacity-restricted deque, it is generally preferable to use offerLast
.
- Specified by:
-
addLast
in interfaceBlockingDeque<E>
- Specified by:
-
addLast
in interfaceDeque<E>
- Parameters:
-
e
- the element to add - Throws:
-
IllegalStateException
- if this deque is full -
NullPointerException
- if the specified element is null
offerFirst
public boolean offerFirst(E e)
Description copied from interface: BlockingDeque
Inserts the specified element at the front of this deque if it is possible to do so immediately without violating capacity restrictions, returning true
upon success and false
if no space is currently available. When using a capacity-restricted deque, this method is generally preferable to the addFirst
method, which can fail to insert an element only by throwing an exception.
- Specified by:
-
offerFirst
in interfaceBlockingDeque<E>
- Specified by:
-
offerFirst
in interfaceDeque<E>
- Parameters:
-
e
- the element to add - Returns:
-
true
if the element was added to this deque, elsefalse
- Throws:
-
NullPointerException
- if the specified element is null
offerLast
public boolean offerLast(E e)
Description copied from interface: BlockingDeque
Inserts the specified element at the end of this deque if it is possible to do so immediately without violating capacity restrictions, returning true
upon success and false
if no space is currently available. When using a capacity-restricted deque, this method is generally preferable to the addLast
method, which can fail to insert an element only by throwing an exception.
- Specified by:
-
offerLast
in interfaceBlockingDeque<E>
- Specified by:
-
offerLast
in interfaceDeque<E>
- Parameters:
-
e
- the element to add - Returns:
-
true
if the element was added to this deque, elsefalse
- Throws:
-
NullPointerException
- if the specified element is null
putFirst
public void putFirst(E e) throws InterruptedException
Description copied from interface: BlockingDeque
Inserts the specified element at the front of this deque, waiting if necessary for space to become available.
- Specified by:
-
putFirst
in interfaceBlockingDeque<E>
- Parameters:
-
e
- the element to add - Throws:
-
NullPointerException
- if the specified element is null -
InterruptedException
- if interrupted while waiting
putLast
public void putLast(E e) throws InterruptedException
Description copied from interface: BlockingDeque
Inserts the specified element at the end of this deque, waiting if necessary for space to become available.
- Specified by:
-
putLast
in interfaceBlockingDeque<E>
- Parameters:
-
e
- the element to add - Throws:
-
NullPointerException
- if the specified element is null -
InterruptedException
- if interrupted while waiting
offerFirst
public boolean offerFirst(E e, long timeout, TimeUnit unit) throws InterruptedException
Description copied from interface: BlockingDeque
Inserts the specified element at the front of this deque, waiting up to the specified wait time if necessary for space to become available.
- Specified by:
-
offerFirst
in interfaceBlockingDeque<E>
- Parameters:
-
e
- the element to add -
timeout
- how long to wait before giving up, in units ofunit
-
unit
- aTimeUnit
determining how to interpret thetimeout
parameter - Returns:
-
true
if successful, orfalse
if the specified waiting time elapses before space is available - Throws:
-
NullPointerException
- if the specified element is null -
InterruptedException
- if interrupted while waiting
offerLast
public boolean offerLast(E e, long timeout, TimeUnit unit) throws InterruptedException
Description copied from interface: BlockingDeque
Inserts the specified element at the end of this deque, waiting up to the specified wait time if necessary for space to become available.
- Specified by:
-
offerLast
in interfaceBlockingDeque<E>
- Parameters:
-
e
- the element to add -
timeout
- how long to wait before giving up, in units ofunit
-
unit
- aTimeUnit
determining how to interpret thetimeout
parameter - Returns:
-
true
if successful, orfalse
if the specified waiting time elapses before space is available - Throws:
-
NullPointerException
- if the specified element is null -
InterruptedException
- if interrupted while waiting
removeFirst
public E removeFirst()
Description copied from interface: 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.
- Specified by:
-
removeFirst
in interfaceDeque<E>
- Returns:
- the head of this deque
- Throws:
-
NoSuchElementException
- if this deque is empty
removeLast
public E removeLast()
Description copied from interface: 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.
- Specified by:
-
removeLast
in interfaceDeque<E>
- Returns:
- the tail of this deque
- Throws:
-
NoSuchElementException
- if this deque is empty
getFirst
public E getFirst()
Description copied from interface: 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.
- Specified by:
-
getFirst
in interfaceDeque<E>
- Returns:
- the head of this deque
- Throws:
-
NoSuchElementException
- if this deque is empty
getLast
public E getLast()
Description copied from interface: 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.
- Specified by:
-
getLast
in interfaceDeque<E>
- Returns:
- the tail of this deque
- Throws:
-
NoSuchElementException
- if this deque is empty
add
public boolean add(E e)
Inserts the specified element at the end of this deque unless it would violate capacity restrictions. When using a capacity-restricted deque, it is generally preferable to use method offer
.
This method is equivalent to addLast(E)
.
- Specified by:
-
add
in interfaceBlockingDeque<E>
- Specified by:
-
add
in interfaceBlockingQueue<E>
- Specified by:
-
add
in interfaceCollection<E>
- Specified by:
-
add
in interfaceDeque<E>
- Specified by:
-
add
in interfaceQueue<E>
- Overrides:
-
add
in classAbstractQueue<E>
- Parameters:
-
e
- the element to add - Returns:
-
true
(as specified byCollection.add(E)
) - Throws:
-
IllegalStateException
- if this deque is full -
NullPointerException
- if the specified element is null
offer
public boolean offer(E e)
Description copied from interface: BlockingDeque
Inserts the specified element into the queue represented by this deque (in other words, at the tail of this deque) if it is possible to do so immediately without violating capacity restrictions, returning true
upon success and false
if no space is currently available. When using a capacity-restricted deque, this method is generally preferable to the BlockingDeque.add(E)
method, which can fail to insert an element only by throwing an exception.
This method is equivalent to offerLast
.
- Specified by:
-
offer
in interfaceBlockingDeque<E>
- Specified by:
-
offer
in interfaceBlockingQueue<E>
- Specified by:
-
offer
in interfaceDeque<E>
- Specified by:
-
offer
in interfaceQueue<E>
- Parameters:
-
e
- the element to add - Returns:
-
true
if the element was added to this queue, elsefalse
- Throws:
-
NullPointerException
- if the specified element is null
put
public void put(E e) throws InterruptedException
Description copied from interface: BlockingDeque
Inserts the specified element into the queue represented by this deque (in other words, at the tail of this deque), waiting if necessary for space to become available.
This method is equivalent to putLast
.
- Specified by:
-
put
in interfaceBlockingDeque<E>
- Specified by:
-
put
in interfaceBlockingQueue<E>
- Parameters:
-
e
- the element to add - Throws:
-
NullPointerException
- if the specified element is null -
InterruptedException
- if interrupted while waiting
offer
public boolean offer(E e, long timeout, TimeUnit unit) throws InterruptedException
Description copied from interface: BlockingDeque
Inserts the specified element into the queue represented by this deque (in other words, at the tail of this deque), waiting up to the specified wait time if necessary for space to become available.
This method is equivalent to offerLast
.
- Specified by:
-
offer
in interfaceBlockingDeque<E>
- Specified by:
-
offer
in interfaceBlockingQueue<E>
- Parameters:
-
e
- the element to add -
timeout
- how long to wait before giving up, in units ofunit
-
unit
- aTimeUnit
determining how to interpret thetimeout
parameter - Returns:
-
true
if the element was added to this deque, elsefalse
- Throws:
-
NullPointerException
- if the specified element is null -
InterruptedException
- if interrupted while waiting
remove
public E remove()
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
.
- Specified by:
-
remove
in interfaceBlockingDeque<E>
- Specified by:
-
remove
in interfaceDeque<E>
- Specified by:
-
remove
in interfaceQueue<E>
- Overrides:
-
remove
in classAbstractQueue<E>
- Returns:
- the head of the queue represented by this deque
- Throws:
-
NoSuchElementException
- if this deque is empty
element
public E element()
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
.
- Specified by:
-
element
in interfaceBlockingDeque<E>
- Specified by:
-
element
in interfaceDeque<E>
- Specified by:
-
element
in interfaceQueue<E>
- Overrides:
-
element
in classAbstractQueue<E>
- Returns:
- the head of the queue represented by this deque
- Throws:
-
NoSuchElementException
- if this deque is empty
remainingCapacity
public int remainingCapacity()
Returns the number of additional elements that this deque can ideally (in the absence of memory or resource constraints) accept without blocking. This is always equal to the initial capacity of this deque less the current size
of this deque.
Note that you cannot always tell if an attempt to insert an element will succeed by inspecting remainingCapacity
because it may be the case that another thread is about to insert or remove an element.
- Specified by:
-
remainingCapacity
in interfaceBlockingQueue<E>
- Returns:
- the remaining capacity
drainTo
public int drainTo(Collection<? super E> c)
Description copied from interface: BlockingQueue
Removes all available elements from this queue and adds them to the given collection. This operation may be more efficient than repeatedly polling this queue. A failure encountered while attempting to add elements to collection c
may result in elements being in neither, either or both collections when the associated exception is thrown. Attempts to drain a queue to itself result in IllegalArgumentException
. Further, the behavior of this operation is undefined if the specified collection is modified while the operation is in progress.
- Specified by:
-
drainTo
in interfaceBlockingQueue<E>
- Parameters:
-
c
- the collection to transfer elements into - Returns:
- the number of elements transferred
- Throws:
-
UnsupportedOperationException
- if addition of elements is not supported by the specified collection -
ClassCastException
- if the class of an element of this queue prevents it from being added to the specified collection -
NullPointerException
- if the specified collection is null -
IllegalArgumentException
- if the specified collection is this queue, or some property of an element of this queue prevents it from being added to the specified collection
drainTo
public int drainTo(Collection<? super E> c, int maxElements)
Description copied from interface: BlockingQueue
Removes at most the given number of available elements from this queue and adds them to the given collection. A failure encountered while attempting to add elements to collection c
may result in elements being in neither, either or both collections when the associated exception is thrown. Attempts to drain a queue to itself result in IllegalArgumentException
. Further, the behavior of this operation is undefined if the specified collection is modified while the operation is in progress.
- Specified by:
-
drainTo
in interfaceBlockingQueue<E>
- Parameters:
-
c
- the collection to transfer elements into -
maxElements
- the maximum number of elements to transfer - Returns:
- the number of elements transferred
- Throws:
-
UnsupportedOperationException
- if addition of elements is not supported by the specified collection -
ClassCastException
- if the class of an element of this queue prevents it from being added to the specified collection -
NullPointerException
- if the specified collection is null -
IllegalArgumentException
- if the specified collection is this queue, or some property of an element of this queue prevents it from being added to the specified collection
push
public void push(E e)
Description copied from interface: BlockingDeque
Pushes an element onto the stack represented by this deque (in other words, at the head of this deque) if it is possible to do so immediately without violating capacity restrictions, throwing an IllegalStateException
if no space is currently available.
This method is equivalent to addFirst
.
- Specified by:
-
push
in interfaceBlockingDeque<E>
- Specified by:
-
push
in interfaceDeque<E>
- Parameters:
-
e
- the element to push - Throws:
-
IllegalStateException
- if this deque is full -
NullPointerException
- if the specified element is null
pop
public E pop()
Description copied from interface: Deque
Pops an element from the stack represented by this deque. In other words, removes and returns the first element of this deque.
This method is equivalent to Deque.removeFirst()
.
- Specified by:
-
pop
in interfaceDeque<E>
- Returns:
- the element at the front of this deque (which is the top of the stack represented by this deque)
- Throws:
-
NoSuchElementException
- if this deque is empty
remove
public boolean remove(Object o)
Removes the first occurrence 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
.
- Specified by:
-
remove
in interfaceBlockingDeque<E>
- Specified by:
-
remove
in interfaceBlockingQueue<E>
- Specified by:
-
remove
in interfaceCollection<E>
- Specified by:
-
remove
in interfaceDeque<E>
- Overrides:
-
remove
in classAbstractCollection<E>
- Parameters:
-
o
- element to be removed from this deque, if present - Returns:
-
true
if this deque changed as a result of the call
size
public int size()
Returns the number of elements in this deque.
- Specified by:
-
size
in interfaceBlockingDeque<E>
- Specified by:
-
size
in interfaceCollection<E>
- Specified by:
-
size
in interfaceDeque<E>
- Returns:
- the number of elements in this deque
contains
public boolean contains(Object o)
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)
.
- Specified by:
-
contains
in interfaceBlockingDeque<E>
- Specified by:
-
contains
in interfaceBlockingQueue<E>
- Specified by:
-
contains
in interfaceCollection<E>
- Specified by:
-
contains
in interfaceDeque<E>
- Overrides:
-
contains
in classAbstractCollection<E>
- Parameters:
-
o
- object to be checked for containment in this deque - Returns:
-
true
if this deque contains the specified element
addAll
public boolean addAll(Collection<? extends E> c)
Appends all of the elements in the specified collection to the end of this deque, in the order that they are returned by the specified collection's iterator. Attempts to addAll
of a deque to itself result in IllegalArgumentException
.
- Specified by:
-
addAll
in interfaceCollection<E>
- Specified by:
-
addAll
in interfaceDeque<E>
- Overrides:
-
addAll
in classAbstractQueue<E>
- Parameters:
-
c
- the elements to be inserted into this deque - Returns:
-
true
if this deque changed as a result of the call - Throws:
-
NullPointerException
- if the specified collection or any of its elements are null -
IllegalArgumentException
- if the collection is this deque -
IllegalStateException
- if this deque is full - See Also:
add(Object)
toArray
public Object[] toArray()
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.
- Specified by:
-
toArray
in interfaceCollection<E>
- Overrides:
-
toArray
in classAbstractCollection<E>
- Returns:
- an array containing all of the elements in this deque
toArray
public <T> T[] toArray(T[] a)
Returns an array containing all of the elements in this deque, in proper sequence; 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()
.- Specified by:
-
toArray
in interfaceCollection<E>
- Overrides:
-
toArray
in classAbstractCollection<E>
- Type Parameters:
-
T
- the component type of the array to contain the collection - Parameters:
-
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 - Returns:
- an array containing all of the elements in this deque
- Throws:
-
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
clear
public void clear()
Atomically removes all of the elements from this deque. The deque will be empty after this call returns.
- Specified by:
-
clear
in interfaceCollection<E>
- Overrides:
-
clear
in classAbstractQueue<E>
iterator
public Iterator<E> iterator()
Returns an iterator over the elements in this deque in proper sequence. The elements will be returned in order from first (head) to last (tail).
The returned iterator is weakly consistent.
- Specified by:
-
iterator
in interfaceBlockingDeque<E>
- Specified by:
-
iterator
in interfaceCollection<E>
- Specified by:
-
iterator
in interfaceDeque<E>
- Specified by:
-
iterator
in interfaceIterable<E>
- Specified by:
-
iterator
in classAbstractCollection<E>
- Returns:
- an iterator over the elements in this deque in proper sequence
descendingIterator
public Iterator<E> descendingIterator()
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).
The returned iterator is weakly consistent.
- Specified by:
-
descendingIterator
in interfaceDeque<E>
- Returns:
- an iterator over the elements in this deque in reverse order
spliterator
public Spliterator<E> spliterator()
Returns a Spliterator
over the elements in this deque.
The returned spliterator is weakly consistent.
The Spliterator
reports Spliterator.CONCURRENT
, Spliterator.ORDERED
, and Spliterator.NONNULL
.
- Specified by:
-
spliterator
in interfaceCollection<E>
- Specified by:
-
spliterator
in interfaceIterable<E>
- Implementation Note:
- The
Spliterator
implementstrySplit
to permit limited parallelism. - Returns:
- a
Spliterator
over the elements in this deque - Since:
- 1.8
forEach
public void forEach(Consumer<? super E> action)
Description copied from interface: 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.
- Specified by:
-
forEach
in interfaceIterable<E>
- Parameters:
-
action
- The action to be performed for each element - Throws:
-
NullPointerException
- if the specified action is null
removeIf
public boolean removeIf(Predicate<? super E> filter)
Description copied from interface: Collection
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.
- Specified by:
-
removeIf
in interfaceCollection<E>
- Parameters:
-
filter
- a predicate which returnstrue
for elements to be removed - Returns:
-
true
if any elements were removed - Throws:
-
NullPointerException
- if the specified filter is null
removeAll
public boolean removeAll(Collection<?> c)
Description copied from class: AbstractCollection
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.
- Specified by:
-
removeAll
in interfaceCollection<E>
- Overrides:
-
removeAll
in classAbstractCollection<E>
- Parameters:
-
c
- collection containing elements to be removed from this collection - Returns:
-
true
if this collection changed as a result of the call - Throws:
-
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 - See Also:
-
AbstractCollection.remove(Object)
,AbstractCollection.contains(Object)
retainAll
public boolean retainAll(Collection<?> c)
Description copied from class: AbstractCollection
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.
- Specified by:
-
retainAll
in interfaceCollection<E>
- Overrides:
-
retainAll
in classAbstractCollection<E>
- Parameters:
-
c
- collection containing elements to be retained in this collection - Returns:
-
true
if this collection changed as a result of the call - Throws:
-
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 - See Also:
-
AbstractCollection.remove(Object)
,AbstractCollection.contains(Object)