Added in [API level 9](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels) Summary: [Ctors](https://developer.android.com/reference/java/util/concurrent/LinkedBlockingDeque#pubctors) \| [Methods](https://developer.android.com/reference/java/util/concurrent/LinkedBlockingDeque#pubmethods) \| [Inherited Methods](https://developer.android.com/reference/java/util/concurrent/LinkedBlockingDeque#inhmethods) # LinkedBlockingDeque ` public class LinkedBlockingDeque ` ` ` ` ` ` extends https://developer.android.com/reference/java/util/AbstractQueue ` ` implements https://developer.android.com/reference/java/util/concurrent/BlockingDeque, https://developer.android.com/reference/java/io/Serializable ` |---|---|---|---| | [java.lang.Object](https://developer.android.com/reference/java/lang/Object) |||| | ↳ | [java.util.AbstractCollection](https://developer.android.com/reference/java/util/AbstractCollection)\ ||| | | ↳ | [java.util.AbstractQueue](https://developer.android.com/reference/java/util/AbstractQueue)\ || | | | ↳ | java.util.concurrent.LinkedBlockingDeque\ |
*** ** * ** *** An optionally-bounded [blocking deque](https://developer.android.com/reference/java/util/concurrent/BlockingDeque) 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 `https://developer.android.com/reference/java/lang/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 `https://developer.android.com/reference/java/util/concurrent/LinkedBlockingDeque#remove(java.lang.Object)`, `https://developer.android.com/reference/java/util/concurrent/LinkedBlockingDeque#removeFirstOccurrence(java.lang.Object)`, `https://developer.android.com/reference/java/util/concurrent/LinkedBlockingDeque#removeLastOccurrence(java.lang.Object)`, `https://developer.android.com/reference/java/util/concurrent/LinkedBlockingDeque#contains(java.lang.Object)`, and the bulk operations, all of which run in linear time. This class and its iterator implement all of the *optional* methods of the `https://developer.android.com/reference/java/util/Collection` and `https://developer.android.com/reference/java/util/Iterator` interfaces. This class is a member of the [Java Collections Framework](https://reference/java/util/package-summary.html#CollectionsFramework). ## Summary | ### Public constructors || |---|---| | ` https://developer.android.com/reference/java/util/concurrent/LinkedBlockingDeque#LinkedBlockingDeque()() ` Creates a `LinkedBlockingDeque` with a capacity of `https://developer.android.com/reference/java/lang/Integer#MAX_VALUE`. | | ` https://developer.android.com/reference/java/util/concurrent/LinkedBlockingDeque#LinkedBlockingDeque(int)(int capacity) ` Creates a `LinkedBlockingDeque` with the given (fixed) capacity. | | ` https://developer.android.com/reference/java/util/concurrent/LinkedBlockingDeque#LinkedBlockingDeque(java.util.Collection)(https://developer.android.com/reference/java/util/Collection c) ` Creates a `LinkedBlockingDeque` with a capacity of `https://developer.android.com/reference/java/lang/Integer#MAX_VALUE`, initially containing the elements of the given collection, added in traversal order of the collection's iterator. | | ### Public methods || |---|---| | ` boolean` | ` https://developer.android.com/reference/java/util/concurrent/LinkedBlockingDeque#add(E)(E e) ` Inserts the specified element at the end of this deque unless it would violate capacity restrictions. | | ` boolean` | ` https://developer.android.com/reference/java/util/concurrent/LinkedBlockingDeque#addAll(java.util.Collection)(https://developer.android.com/reference/java/util/Collection 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` | ` https://developer.android.com/reference/java/util/concurrent/LinkedBlockingDeque#addFirst(E)(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 `IllegalStateException` if no space is currently available. | | ` void` | ` https://developer.android.com/reference/java/util/concurrent/LinkedBlockingDeque#addLast(E)(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 `IllegalStateException` if no space is currently available. | | ` void` | ` https://developer.android.com/reference/java/util/concurrent/LinkedBlockingDeque#clear()() ` Atomically removes all of the elements from this deque. | | ` boolean` | ` https://developer.android.com/reference/java/util/concurrent/LinkedBlockingDeque#contains(java.lang.Object)(https://developer.android.com/reference/java/lang/Object o) ` Returns `true` if this deque contains the specified element. | | ` https://developer.android.com/reference/java/util/Iterator` | ` https://developer.android.com/reference/java/util/concurrent/LinkedBlockingDeque#descendingIterator()() ` Returns an iterator over the elements in this deque in reverse sequential order. | | ` int` | ` https://developer.android.com/reference/java/util/concurrent/LinkedBlockingDeque#drainTo(java.util.Collection,%20int)(https://developer.android.com/reference/java/util/Collection c, int maxElements) ` Removes at most the given number of available elements from this queue and adds them to the given collection. | | ` int` | ` https://developer.android.com/reference/java/util/concurrent/LinkedBlockingDeque#drainTo(java.util.Collection)(https://developer.android.com/reference/java/util/Collection c) ` Removes all available elements from this queue and adds them to the given collection. | | ` E` | ` https://developer.android.com/reference/java/util/concurrent/LinkedBlockingDeque#element()() ` Retrieves, but does not remove, the head of the queue represented by this deque. | | ` void` | ` https://developer.android.com/reference/java/util/concurrent/LinkedBlockingDeque#forEach(java.util.function.Consumer)(https://developer.android.com/reference/java/util/function/Consumer action) ` | | ` E` | ` https://developer.android.com/reference/java/util/concurrent/LinkedBlockingDeque#getFirst()() ` Retrieves, but does not remove, the first element of this deque. | | ` E` | ` https://developer.android.com/reference/java/util/concurrent/LinkedBlockingDeque#getLast()() ` Retrieves, but does not remove, the last element of this deque. | | ` https://developer.android.com/reference/java/util/Iterator` | ` https://developer.android.com/reference/java/util/concurrent/LinkedBlockingDeque#iterator()() ` Returns an iterator over the elements in this deque in proper sequence. | | ` boolean` | ` https://developer.android.com/reference/java/util/concurrent/LinkedBlockingDeque#offer(E,%20long,%20java.util.concurrent.TimeUnit)(E e, long timeout, https://developer.android.com/reference/java/util/concurrent/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` | ` https://developer.android.com/reference/java/util/concurrent/LinkedBlockingDeque#offer(E)(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 `true` upon success and `false` if no space is currently available. | | ` boolean` | ` https://developer.android.com/reference/java/util/concurrent/LinkedBlockingDeque#offerFirst(E)(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 `true` upon success and `false` if no space is currently available. | | ` boolean` | ` https://developer.android.com/reference/java/util/concurrent/LinkedBlockingDeque#offerFirst(E,%20long,%20java.util.concurrent.TimeUnit)(E e, long timeout, https://developer.android.com/reference/java/util/concurrent/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` | ` https://developer.android.com/reference/java/util/concurrent/LinkedBlockingDeque#offerLast(E)(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 `true` upon success and `false` if no space is currently available. | | ` boolean` | ` https://developer.android.com/reference/java/util/concurrent/LinkedBlockingDeque#offerLast(E,%20long,%20java.util.concurrent.TimeUnit)(E e, long timeout, https://developer.android.com/reference/java/util/concurrent/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` | ` https://developer.android.com/reference/java/util/concurrent/LinkedBlockingDeque#peek()() ` Retrieves, but does not remove, 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. | | ` E` | ` https://developer.android.com/reference/java/util/concurrent/LinkedBlockingDeque#peekFirst()() ` Retrieves, but does not remove, the first element of this deque, or returns `null` if this deque is empty. | | ` E` | ` https://developer.android.com/reference/java/util/concurrent/LinkedBlockingDeque#peekLast()() ` Retrieves, but does not remove, the last element of this deque, or returns `null` if this deque is empty. | | ` E` | ` https://developer.android.com/reference/java/util/concurrent/LinkedBlockingDeque#poll(long,%20java.util.concurrent.TimeUnit)(long timeout, https://developer.android.com/reference/java/util/concurrent/TimeUnit unit) ` Retrieves and removes the head of the queue represented by this deque (in other words, the first element of this deque), waiting up to the specified wait time if necessary for an element to become available. | | ` E` | ` https://developer.android.com/reference/java/util/concurrent/LinkedBlockingDeque#poll()() ` 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. | | ` E` | ` https://developer.android.com/reference/java/util/concurrent/LinkedBlockingDeque#pollFirst()() ` Retrieves and removes the first element of this deque, or returns `null` if this deque is empty. | | ` E` | ` https://developer.android.com/reference/java/util/concurrent/LinkedBlockingDeque#pollFirst(long,%20java.util.concurrent.TimeUnit)(long timeout, https://developer.android.com/reference/java/util/concurrent/TimeUnit unit) ` Retrieves and removes the first element of this deque, waiting up to the specified wait time if necessary for an element to become available. | | ` E` | ` https://developer.android.com/reference/java/util/concurrent/LinkedBlockingDeque#pollLast()() ` Retrieves and removes the last element of this deque, or returns `null` if this deque is empty. | | ` E` | ` https://developer.android.com/reference/java/util/concurrent/LinkedBlockingDeque#pollLast(long,%20java.util.concurrent.TimeUnit)(long timeout, https://developer.android.com/reference/java/util/concurrent/TimeUnit unit) ` Retrieves and removes the last element of this deque, waiting up to the specified wait time if necessary for an element to become available. | | ` E` | ` https://developer.android.com/reference/java/util/concurrent/LinkedBlockingDeque#pop()() ` Pops an element from the stack represented by this deque. | | ` void` | ` https://developer.android.com/reference/java/util/concurrent/LinkedBlockingDeque#push(E)(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 `IllegalStateException` if no space is currently available. | | ` void` | ` https://developer.android.com/reference/java/util/concurrent/LinkedBlockingDeque#put(E)(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` | ` https://developer.android.com/reference/java/util/concurrent/LinkedBlockingDeque#putFirst(E)(E e) ` Inserts the specified element at the front of this deque, waiting if necessary for space to become available. | | ` void` | ` https://developer.android.com/reference/java/util/concurrent/LinkedBlockingDeque#putLast(E)(E e) ` Inserts the specified element at the end of this deque, waiting if necessary for space to become available. | | ` int` | ` https://developer.android.com/reference/java/util/concurrent/LinkedBlockingDeque#remainingCapacity()() ` Returns the number of additional elements that this deque can ideally (in the absence of memory or resource constraints) accept without blocking. | | ` boolean` | ` https://developer.android.com/reference/java/util/concurrent/LinkedBlockingDeque#remove(java.lang.Object)(https://developer.android.com/reference/java/lang/Object o) ` Removes the first occurrence of the specified element from this deque. | | ` E` | ` https://developer.android.com/reference/java/util/concurrent/LinkedBlockingDeque#remove()() ` Retrieves and removes the head of the queue represented by this deque. | | ` boolean` | ` https://developer.android.com/reference/java/util/concurrent/LinkedBlockingDeque#removeAll(java.util.Collection)(https://developer.android.com/reference/java/util/Collection c) ` Removes all of this collection's elements that are also contained in the specified collection (optional operation). | | ` E` | ` https://developer.android.com/reference/java/util/concurrent/LinkedBlockingDeque#removeFirst()() ` Retrieves and removes the first element of this deque. | | ` boolean` | ` https://developer.android.com/reference/java/util/concurrent/LinkedBlockingDeque#removeFirstOccurrence(java.lang.Object)(https://developer.android.com/reference/java/lang/Object o) ` Removes the first occurrence of the specified element from this deque. | | ` boolean` | ` https://developer.android.com/reference/java/util/concurrent/LinkedBlockingDeque#removeIf(java.util.function.Predicate)(https://developer.android.com/reference/java/util/function/Predicate filter) ` Removes all of the elements of this collection that satisfy the given predicate (optional operation). | | ` E` | ` https://developer.android.com/reference/java/util/concurrent/LinkedBlockingDeque#removeLast()() ` Retrieves and removes the last element of this deque. | | ` boolean` | ` https://developer.android.com/reference/java/util/concurrent/LinkedBlockingDeque#removeLastOccurrence(java.lang.Object)(https://developer.android.com/reference/java/lang/Object o) ` Removes the last occurrence of the specified element from this deque. | | ` boolean` | ` https://developer.android.com/reference/java/util/concurrent/LinkedBlockingDeque#retainAll(java.util.Collection)(https://developer.android.com/reference/java/util/Collection c) ` Retains only the elements in this collection that are contained in the specified collection (optional operation). | | ` int` | ` https://developer.android.com/reference/java/util/concurrent/LinkedBlockingDeque#size()() ` Returns the number of elements in this deque. | | ` https://developer.android.com/reference/java/util/Spliterator` | ` https://developer.android.com/reference/java/util/concurrent/LinkedBlockingDeque#spliterator()() ` Returns a `https://developer.android.com/reference/java/util/Spliterator` over the elements in this deque. | | ` E` | ` https://developer.android.com/reference/java/util/concurrent/LinkedBlockingDeque#take()() ` Retrieves and removes the head of the queue represented by this deque (in other words, the first element of this deque), waiting if necessary until an element becomes available. | | ` E` | ` https://developer.android.com/reference/java/util/concurrent/LinkedBlockingDeque#takeFirst()() ` Retrieves and removes the first element of this deque, waiting if necessary until an element becomes available. | | ` E` | ` https://developer.android.com/reference/java/util/concurrent/LinkedBlockingDeque#takeLast()() ` Retrieves and removes the last element of this deque, waiting if necessary until an element becomes available. | | ` https://developer.android.com/reference/java/lang/Object` | ` https://developer.android.com/reference/java/util/concurrent/LinkedBlockingDeque#toArray()() ` Returns an array containing all of the elements in this deque, in proper sequence (from first to last element). | | ` T[]` | ` https://developer.android.com/reference/java/util/concurrent/LinkedBlockingDeque#toArray(T[])(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. | | ` https://developer.android.com/reference/java/lang/String` | ` https://developer.android.com/reference/java/util/concurrent/LinkedBlockingDeque#toString()() ` Returns a string representation of this collection. | | ### Inherited methods | |---|---| | From class ` https://developer.android.com/reference/java/util/AbstractQueue ` |---|---| | ` boolean` | ` https://developer.android.com/reference/java/util/AbstractQueue#add(E)(E e) ` Inserts the specified element into this queue if it is possible to do so immediately without violating capacity restrictions, returning `true` upon success and throwing an `IllegalStateException` if no space is currently available. | | ` boolean` | ` https://developer.android.com/reference/java/util/AbstractQueue#addAll(java.util.Collection)(https://developer.android.com/reference/java/util/Collection c) ` Adds all of the elements in the specified collection to this queue. | | ` void` | ` https://developer.android.com/reference/java/util/AbstractQueue#clear()() ` Removes all of the elements from this queue. | | ` E` | ` https://developer.android.com/reference/java/util/AbstractQueue#element()() ` Retrieves, but does not remove, the head of this queue. | | ` E` | ` https://developer.android.com/reference/java/util/AbstractQueue#remove()() ` Retrieves and removes the head of this queue. | || | From class ` https://developer.android.com/reference/java/util/AbstractCollection ` |---|---| | ` boolean` | ` https://developer.android.com/reference/java/util/AbstractCollection#add(E)(E e) ` Ensures that this collection contains the specified element (optional operation). | | ` boolean` | ` https://developer.android.com/reference/java/util/AbstractCollection#addAll(java.util.Collection)(https://developer.android.com/reference/java/util/Collection c) ` Adds all of the elements in the specified collection to this collection (optional operation). | | ` void` | ` https://developer.android.com/reference/java/util/AbstractCollection#clear()() ` Removes all of the elements from this collection (optional operation). | | ` boolean` | ` https://developer.android.com/reference/java/util/AbstractCollection#contains(java.lang.Object)(https://developer.android.com/reference/java/lang/Object o) ` Returns `true` if this collection contains the specified element. | | ` boolean` | ` https://developer.android.com/reference/java/util/AbstractCollection#containsAll(java.util.Collection)(https://developer.android.com/reference/java/util/Collection c) ` Returns `true` if this collection contains all of the elements in the specified collection. | | ` boolean` | ` https://developer.android.com/reference/java/util/AbstractCollection#isEmpty()() ` Returns `true` if this collection contains no elements. | | ` abstract https://developer.android.com/reference/java/util/Iterator` | ` https://developer.android.com/reference/java/util/AbstractCollection#iterator()() ` Returns an iterator over the elements contained in this collection. | | ` boolean` | ` https://developer.android.com/reference/java/util/AbstractCollection#remove(java.lang.Object)(https://developer.android.com/reference/java/lang/Object o) ` Removes a single instance of the specified element from this collection, if it is present (optional operation). | | ` boolean` | ` https://developer.android.com/reference/java/util/AbstractCollection#removeAll(java.util.Collection)(https://developer.android.com/reference/java/util/Collection c) ` Removes all of this collection's elements that are also contained in the specified collection (optional operation). | | ` boolean` | ` https://developer.android.com/reference/java/util/AbstractCollection#retainAll(java.util.Collection)(https://developer.android.com/reference/java/util/Collection c) ` Retains only the elements in this collection that are contained in the specified collection (optional operation). | | ` abstract int` | ` https://developer.android.com/reference/java/util/AbstractCollection#size()() ` Returns the number of elements in this collection. | | ` T[]` | ` https://developer.android.com/reference/java/util/AbstractCollection#toArray(T[])(T[] a) ` Returns an array containing all of the elements in this collection; the runtime type of the returned array is that of the specified array. | | ` https://developer.android.com/reference/java/lang/Object` | ` https://developer.android.com/reference/java/util/AbstractCollection#toArray()() ` Returns an array containing all of the elements in this collection. | | ` https://developer.android.com/reference/java/lang/String` | ` https://developer.android.com/reference/java/util/AbstractCollection#toString()() ` Returns a string representation of this collection. | || | From class ` https://developer.android.com/reference/java/lang/Object ` |---|---| | ` https://developer.android.com/reference/java/lang/Object` | ` https://developer.android.com/reference/java/lang/Object#clone()() ` Creates and returns a copy of this object. | | ` boolean` | ` https://developer.android.com/reference/java/lang/Object#equals(java.lang.Object)(https://developer.android.com/reference/java/lang/Object obj) ` Indicates whether some other object is "equal to" this one. | | ` void` | ` https://developer.android.com/reference/java/lang/Object#finalize()() ` Called by the garbage collector on an object when garbage collection determines that there are no more references to the object. | | ` final https://developer.android.com/reference/java/lang/Class` | ` https://developer.android.com/reference/java/lang/Object#getClass()() ` Returns the runtime class of this `Object`. | | ` int` | ` https://developer.android.com/reference/java/lang/Object#hashCode()() ` Returns a hash code value for the object. | | ` final void` | ` https://developer.android.com/reference/java/lang/Object#notify()() ` Wakes up a single thread that is waiting on this object's monitor. | | ` final void` | ` https://developer.android.com/reference/java/lang/Object#notifyAll()() ` Wakes up all threads that are waiting on this object's monitor. | | ` https://developer.android.com/reference/java/lang/String` | ` https://developer.android.com/reference/java/lang/Object#toString()() ` Returns a string representation of the object. | | ` final void` | ` https://developer.android.com/reference/java/lang/Object#wait(long,%20int)(long timeoutMillis, int nanos) ` Causes the current thread to wait until it is awakened, typically by being *notified* or *interrupted*, or until a certain amount of real time has elapsed. | | ` final void` | ` https://developer.android.com/reference/java/lang/Object#wait(long)(long timeoutMillis) ` Causes the current thread to wait until it is awakened, typically by being *notified* or *interrupted*, or until a certain amount of real time has elapsed. | | ` final void` | ` https://developer.android.com/reference/java/lang/Object#wait()() ` Causes the current thread to wait until it is awakened, typically by being *notified* or *interrupted*. | || | From interface ` https://developer.android.com/reference/java/util/Queue ` |---|---| | ` abstract boolean` | ` https://developer.android.com/reference/java/util/Queue#add(E)(E e) ` Inserts the specified element into this queue if it is possible to do so immediately without violating capacity restrictions, returning `true` upon success and throwing an `IllegalStateException` if no space is currently available. | | ` abstract E` | ` https://developer.android.com/reference/java/util/Queue#element()() ` Retrieves, but does not remove, the head of this queue. | | ` abstract boolean` | ` https://developer.android.com/reference/java/util/Queue#offer(E)(E e) ` Inserts the specified element into this queue if it is possible to do so immediately without violating capacity restrictions. | | ` abstract E` | ` https://developer.android.com/reference/java/util/Queue#peek()() ` Retrieves, but does not remove, the head of this queue, or returns `null` if this queue is empty. | | ` abstract E` | ` https://developer.android.com/reference/java/util/Queue#poll()() ` Retrieves and removes the head of this queue, or returns `null` if this queue is empty. | | ` abstract E` | ` https://developer.android.com/reference/java/util/Queue#remove()() ` Retrieves and removes the head of this queue. | || | From interface ` https://developer.android.com/reference/java/util/Collection ` |---|---| | ` abstract boolean` | ` https://developer.android.com/reference/java/util/Collection#add(E)(E e) ` Ensures that this collection contains the specified element (optional operation). | | ` abstract boolean` | ` https://developer.android.com/reference/java/util/Collection#addAll(java.util.Collection)(https://developer.android.com/reference/java/util/Collection c) ` Adds all of the elements in the specified collection to this collection (optional operation). | | ` abstract void` | ` https://developer.android.com/reference/java/util/Collection#clear()() ` Removes all of the elements from this collection (optional operation). | | ` abstract boolean` | ` https://developer.android.com/reference/java/util/Collection#contains(java.lang.Object)(https://developer.android.com/reference/java/lang/Object o) ` Returns `true` if this collection contains the specified element. | | ` abstract boolean` | ` https://developer.android.com/reference/java/util/Collection#containsAll(java.util.Collection)(https://developer.android.com/reference/java/util/Collection c) ` Returns `true` if this collection contains all of the elements in the specified collection. | | ` abstract boolean` | ` https://developer.android.com/reference/java/util/Collection#equals(java.lang.Object)(https://developer.android.com/reference/java/lang/Object o) ` Compares the specified object with this collection for equality. | | ` abstract int` | ` https://developer.android.com/reference/java/util/Collection#hashCode()() ` Returns the hash code value for this collection. | | ` abstract boolean` | ` https://developer.android.com/reference/java/util/Collection#isEmpty()() ` Returns `true` if this collection contains no elements. | | ` abstract https://developer.android.com/reference/java/util/Iterator` | ` https://developer.android.com/reference/java/util/Collection#iterator()() ` Returns an iterator over the elements in this collection. | | ` default https://developer.android.com/reference/java/util/stream/Stream` | ` https://developer.android.com/reference/java/util/Collection#parallelStream()() ` Returns a possibly parallel `Stream` with this collection as its source. | | ` abstract boolean` | ` https://developer.android.com/reference/java/util/Collection#remove(java.lang.Object)(https://developer.android.com/reference/java/lang/Object o) ` Removes a single instance of the specified element from this collection, if it is present (optional operation). | | ` abstract boolean` | ` https://developer.android.com/reference/java/util/Collection#removeAll(java.util.Collection)(https://developer.android.com/reference/java/util/Collection c) ` Removes all of this collection's elements that are also contained in the specified collection (optional operation). | | ` default boolean` | ` https://developer.android.com/reference/java/util/Collection#removeIf(java.util.function.Predicate)(https://developer.android.com/reference/java/util/function/Predicate filter) ` Removes all of the elements of this collection that satisfy the given predicate (optional operation). | | ` abstract boolean` | ` https://developer.android.com/reference/java/util/Collection#retainAll(java.util.Collection)(https://developer.android.com/reference/java/util/Collection c) ` Retains only the elements in this collection that are contained in the specified collection (optional operation). | | ` abstract int` | ` https://developer.android.com/reference/java/util/Collection#size()() ` Returns the number of elements in this collection. | | ` default https://developer.android.com/reference/java/util/Spliterator` | ` https://developer.android.com/reference/java/util/Collection#spliterator()() ` Creates a `https://developer.android.com/reference/java/util/Spliterator` over the elements in this collection. | | ` default https://developer.android.com/reference/java/util/stream/Stream` | ` https://developer.android.com/reference/java/util/Collection#stream()() ` Returns a sequential `Stream` with this collection as its source. | | ` abstract T[]` | ` https://developer.android.com/reference/java/util/Collection#toArray(T[])(T[] a) ` Returns an array containing all of the elements in this collection; the runtime type of the returned array is that of the specified array. | | ` abstract https://developer.android.com/reference/java/lang/Object` | ` https://developer.android.com/reference/java/util/Collection#toArray()() ` Returns an array containing all of the elements in this collection. | | ` default T[]` | ` https://developer.android.com/reference/java/util/Collection#toArray(java.util.function.IntFunction)(https://developer.android.com/reference/java/util/function/IntFunction generator) ` Returns an array containing all of the elements in this collection, using the provided `generator` function to allocate the returned array. | || | From interface ` https://developer.android.com/reference/java/util/concurrent/BlockingDeque ` |---|---| | ` abstract boolean` | ` https://developer.android.com/reference/java/util/concurrent/BlockingDeque#add(E)(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 `true` upon success and throwing an `IllegalStateException` if no space is currently available. | | ` abstract void` | ` https://developer.android.com/reference/java/util/concurrent/BlockingDeque#addFirst(E)(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 `IllegalStateException` if no space is currently available. | | ` abstract void` | ` https://developer.android.com/reference/java/util/concurrent/BlockingDeque#addLast(E)(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 `IllegalStateException` if no space is currently available. | | ` abstract boolean` | ` https://developer.android.com/reference/java/util/concurrent/BlockingDeque#contains(java.lang.Object)(https://developer.android.com/reference/java/lang/Object o) ` Returns `true` if this deque contains the specified element. | | ` abstract E` | ` https://developer.android.com/reference/java/util/concurrent/BlockingDeque#element()() ` Retrieves, but does not remove, the head of the queue represented by this deque (in other words, the first element of this deque). | | ` abstract https://developer.android.com/reference/java/util/Iterator` | ` https://developer.android.com/reference/java/util/concurrent/BlockingDeque#iterator()() ` Returns an iterator over the elements in this deque in proper sequence. | | ` abstract boolean` | ` https://developer.android.com/reference/java/util/concurrent/BlockingDeque#offer(E,%20long,%20java.util.concurrent.TimeUnit)(E e, long timeout, https://developer.android.com/reference/java/util/concurrent/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. | | ` abstract boolean` | ` https://developer.android.com/reference/java/util/concurrent/BlockingDeque#offer(E)(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 `true` upon success and `false` if no space is currently available. | | ` abstract boolean` | ` https://developer.android.com/reference/java/util/concurrent/BlockingDeque#offerFirst(E)(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 `true` upon success and `false` if no space is currently available. | | ` abstract boolean` | ` https://developer.android.com/reference/java/util/concurrent/BlockingDeque#offerFirst(E,%20long,%20java.util.concurrent.TimeUnit)(E e, long timeout, https://developer.android.com/reference/java/util/concurrent/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. | | ` abstract boolean` | ` https://developer.android.com/reference/java/util/concurrent/BlockingDeque#offerLast(E)(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 `true` upon success and `false` if no space is currently available. | | ` abstract boolean` | ` https://developer.android.com/reference/java/util/concurrent/BlockingDeque#offerLast(E,%20long,%20java.util.concurrent.TimeUnit)(E e, long timeout, https://developer.android.com/reference/java/util/concurrent/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. | | ` abstract E` | ` https://developer.android.com/reference/java/util/concurrent/BlockingDeque#peek()() ` Retrieves, but does not remove, 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. | | ` abstract E` | ` https://developer.android.com/reference/java/util/concurrent/BlockingDeque#poll(long,%20java.util.concurrent.TimeUnit)(long timeout, https://developer.android.com/reference/java/util/concurrent/TimeUnit unit) ` Retrieves and removes the head of the queue represented by this deque (in other words, the first element of this deque), waiting up to the specified wait time if necessary for an element to become available. | | ` abstract E` | ` https://developer.android.com/reference/java/util/concurrent/BlockingDeque#poll()() ` 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. | | ` abstract E` | ` https://developer.android.com/reference/java/util/concurrent/BlockingDeque#pollFirst(long,%20java.util.concurrent.TimeUnit)(long timeout, https://developer.android.com/reference/java/util/concurrent/TimeUnit unit) ` Retrieves and removes the first element of this deque, waiting up to the specified wait time if necessary for an element to become available. | | ` abstract E` | ` https://developer.android.com/reference/java/util/concurrent/BlockingDeque#pollLast(long,%20java.util.concurrent.TimeUnit)(long timeout, https://developer.android.com/reference/java/util/concurrent/TimeUnit unit) ` Retrieves and removes the last element of this deque, waiting up to the specified wait time if necessary for an element to become available. | | ` abstract void` | ` https://developer.android.com/reference/java/util/concurrent/BlockingDeque#push(E)(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 `IllegalStateException` if no space is currently available. | | ` abstract void` | ` https://developer.android.com/reference/java/util/concurrent/BlockingDeque#put(E)(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. | | ` abstract void` | ` https://developer.android.com/reference/java/util/concurrent/BlockingDeque#putFirst(E)(E e) ` Inserts the specified element at the front of this deque, waiting if necessary for space to become available. | | ` abstract void` | ` https://developer.android.com/reference/java/util/concurrent/BlockingDeque#putLast(E)(E e) ` Inserts the specified element at the end of this deque, waiting if necessary for space to become available. | | ` abstract E` | ` https://developer.android.com/reference/java/util/concurrent/BlockingDeque#remove()() ` Retrieves and removes the head of the queue represented by this deque (in other words, the first element of this deque). | | ` abstract boolean` | ` https://developer.android.com/reference/java/util/concurrent/BlockingDeque#remove(java.lang.Object)(https://developer.android.com/reference/java/lang/Object o) ` Removes the first occurrence of the specified element from this deque. | | ` abstract boolean` | ` https://developer.android.com/reference/java/util/concurrent/BlockingDeque#removeFirstOccurrence(java.lang.Object)(https://developer.android.com/reference/java/lang/Object o) ` Removes the first occurrence of the specified element from this deque. | | ` abstract boolean` | ` https://developer.android.com/reference/java/util/concurrent/BlockingDeque#removeLastOccurrence(java.lang.Object)(https://developer.android.com/reference/java/lang/Object o) ` Removes the last occurrence of the specified element from this deque. | | ` abstract int` | ` https://developer.android.com/reference/java/util/concurrent/BlockingDeque#size()() ` Returns the number of elements in this deque. | | ` abstract E` | ` https://developer.android.com/reference/java/util/concurrent/BlockingDeque#take()() ` Retrieves and removes the head of the queue represented by this deque (in other words, the first element of this deque), waiting if necessary until an element becomes available. | | ` abstract E` | ` https://developer.android.com/reference/java/util/concurrent/BlockingDeque#takeFirst()() ` Retrieves and removes the first element of this deque, waiting if necessary until an element becomes available. | | ` abstract E` | ` https://developer.android.com/reference/java/util/concurrent/BlockingDeque#takeLast()() ` Retrieves and removes the last element of this deque, waiting if necessary until an element becomes available. | || | From interface ` https://developer.android.com/reference/java/lang/Iterable ` |---|---| | ` default void` | ` https://developer.android.com/reference/java/lang/Iterable#forEach(java.util.function.Consumer)(https://developer.android.com/reference/java/util/function/Consumer action) ` Performs the given action for each element of the `Iterable` until all elements have been processed or the action throws an exception. | | ` abstract https://developer.android.com/reference/java/util/Iterator` | ` https://developer.android.com/reference/java/lang/Iterable#iterator()() ` Returns an iterator over elements of type `T`. | | ` default https://developer.android.com/reference/java/util/Spliterator` | ` https://developer.android.com/reference/java/lang/Iterable#spliterator()() ` Creates a `https://developer.android.com/reference/java/util/Spliterator` over the elements described by this `Iterable`. | || | From interface ` https://developer.android.com/reference/java/util/concurrent/BlockingQueue ` |---|---| | ` abstract boolean` | ` https://developer.android.com/reference/java/util/concurrent/BlockingQueue#add(E)(E e) ` Inserts the specified element into this queue if it is possible to do so immediately without violating capacity restrictions, returning `true` upon success and throwing an `IllegalStateException` if no space is currently available. | | ` abstract boolean` | ` https://developer.android.com/reference/java/util/concurrent/BlockingQueue#contains(java.lang.Object)(https://developer.android.com/reference/java/lang/Object o) ` Returns `true` if this queue contains the specified element. | | ` abstract int` | ` https://developer.android.com/reference/java/util/concurrent/BlockingQueue#drainTo(java.util.Collection)(https://developer.android.com/reference/java/util/Collection c) ` Removes all available elements from this queue and adds them to the given collection. | | ` abstract int` | ` https://developer.android.com/reference/java/util/concurrent/BlockingQueue#drainTo(java.util.Collection,%20int)(https://developer.android.com/reference/java/util/Collection c, int maxElements) ` Removes at most the given number of available elements from this queue and adds them to the given collection. | | ` abstract boolean` | ` https://developer.android.com/reference/java/util/concurrent/BlockingQueue#offer(E)(E e) ` Inserts the specified element into this queue if it is possible to do so immediately without violating capacity restrictions, returning `true` upon success and `false` if no space is currently available. | | ` abstract boolean` | ` https://developer.android.com/reference/java/util/concurrent/BlockingQueue#offer(E,%20long,%20java.util.concurrent.TimeUnit)(E e, long timeout, https://developer.android.com/reference/java/util/concurrent/TimeUnit unit) ` Inserts the specified element into this queue, waiting up to the specified wait time if necessary for space to become available. | | ` abstract E` | ` https://developer.android.com/reference/java/util/concurrent/BlockingQueue#poll(long,%20java.util.concurrent.TimeUnit)(long timeout, https://developer.android.com/reference/java/util/concurrent/TimeUnit unit) ` Retrieves and removes the head of this queue, waiting up to the specified wait time if necessary for an element to become available. | | ` abstract void` | ` https://developer.android.com/reference/java/util/concurrent/BlockingQueue#put(E)(E e) ` Inserts the specified element into this queue, waiting if necessary for space to become available. | | ` abstract int` | ` https://developer.android.com/reference/java/util/concurrent/BlockingQueue#remainingCapacity()() ` Returns the number of additional elements that this queue can ideally (in the absence of memory or resource constraints) accept without blocking, or `Integer.MAX_VALUE` if there is no intrinsic limit. | | ` abstract boolean` | ` https://developer.android.com/reference/java/util/concurrent/BlockingQueue#remove(java.lang.Object)(https://developer.android.com/reference/java/lang/Object o) ` Removes a single instance of the specified element from this queue, if it is present. | | ` abstract E` | ` https://developer.android.com/reference/java/util/concurrent/BlockingQueue#take()() ` Retrieves and removes the head of this queue, waiting if necessary until an element becomes available. | || | From interface ` https://developer.android.com/reference/java/util/Deque ` |---|---| | ` abstract boolean` | ` https://developer.android.com/reference/java/util/Deque#add(E)(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 `true` upon success and throwing an `IllegalStateException` if no space is currently available. | | ` abstract boolean` | ` https://developer.android.com/reference/java/util/Deque#addAll(java.util.Collection)(https://developer.android.com/reference/java/util/Collection c) ` Adds all of the elements in the specified collection at the end of this deque, as if by calling `https://developer.android.com/reference/java/util/Deque#addLast(E)` on each one, in the order that they are returned by the collection's iterator. | | ` abstract void` | ` https://developer.android.com/reference/java/util/Deque#addFirst(E)(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 `IllegalStateException` if no space is currently available. | | ` abstract void` | ` https://developer.android.com/reference/java/util/Deque#addLast(E)(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 `IllegalStateException` if no space is currently available. | | ` abstract boolean` | ` https://developer.android.com/reference/java/util/Deque#contains(java.lang.Object)(https://developer.android.com/reference/java/lang/Object o) ` Returns `true` if this deque contains the specified element. | | ` abstract https://developer.android.com/reference/java/util/Iterator` | ` https://developer.android.com/reference/java/util/Deque#descendingIterator()() ` Returns an iterator over the elements in this deque in reverse sequential order. | | ` abstract E` | ` https://developer.android.com/reference/java/util/Deque#element()() ` Retrieves, but does not remove, the head of the queue represented by this deque (in other words, the first element of this deque). | | ` abstract E` | ` https://developer.android.com/reference/java/util/Deque#getFirst()() ` Retrieves, but does not remove, the first element of this deque. | | ` abstract E` | ` https://developer.android.com/reference/java/util/Deque#getLast()() ` Retrieves, but does not remove, the last element of this deque. | | ` abstract https://developer.android.com/reference/java/util/Iterator` | ` https://developer.android.com/reference/java/util/Deque#iterator()() ` Returns an iterator over the elements in this deque in proper sequence. | | ` abstract boolean` | ` https://developer.android.com/reference/java/util/Deque#offer(E)(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 `true` upon success and `false` if no space is currently available. | | ` abstract boolean` | ` https://developer.android.com/reference/java/util/Deque#offerFirst(E)(E e) ` Inserts the specified element at the front of this deque unless it would violate capacity restrictions. | | ` abstract boolean` | ` https://developer.android.com/reference/java/util/Deque#offerLast(E)(E e) ` Inserts the specified element at the end of this deque unless it would violate capacity restrictions. | | ` abstract E` | ` https://developer.android.com/reference/java/util/Deque#peek()() ` Retrieves, but does not remove, 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. | | ` abstract E` | ` https://developer.android.com/reference/java/util/Deque#peekFirst()() ` Retrieves, but does not remove, the first element of this deque, or returns `null` if this deque is empty. | | ` abstract E` | ` https://developer.android.com/reference/java/util/Deque#peekLast()() ` Retrieves, but does not remove, the last element of this deque, or returns `null` if this deque is empty. | | ` abstract E` | ` https://developer.android.com/reference/java/util/Deque#poll()() ` 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. | | ` abstract E` | ` https://developer.android.com/reference/java/util/Deque#pollFirst()() ` Retrieves and removes the first element of this deque, or returns `null` if this deque is empty. | | ` abstract E` | ` https://developer.android.com/reference/java/util/Deque#pollLast()() ` Retrieves and removes the last element of this deque, or returns `null` if this deque is empty. | | ` abstract E` | ` https://developer.android.com/reference/java/util/Deque#pop()() ` Pops an element from the stack represented by this deque. | | ` abstract void` | ` https://developer.android.com/reference/java/util/Deque#push(E)(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 `IllegalStateException` if no space is currently available. | | ` abstract E` | ` https://developer.android.com/reference/java/util/Deque#remove()() ` Retrieves and removes the head of the queue represented by this deque (in other words, the first element of this deque). | | ` abstract boolean` | ` https://developer.android.com/reference/java/util/Deque#remove(java.lang.Object)(https://developer.android.com/reference/java/lang/Object o) ` Removes the first occurrence of the specified element from this deque. | | ` abstract E` | ` https://developer.android.com/reference/java/util/Deque#removeFirst()() ` Retrieves and removes the first element of this deque. | | ` abstract boolean` | ` https://developer.android.com/reference/java/util/Deque#removeFirstOccurrence(java.lang.Object)(https://developer.android.com/reference/java/lang/Object o) ` Removes the first occurrence of the specified element from this deque. | | ` abstract E` | ` https://developer.android.com/reference/java/util/Deque#removeLast()() ` Retrieves and removes the last element of this deque. | | ` abstract boolean` | ` https://developer.android.com/reference/java/util/Deque#removeLastOccurrence(java.lang.Object)(https://developer.android.com/reference/java/lang/Object o) ` Removes the last occurrence of the specified element from this deque. | | ` default https://developer.android.com/reference/java/util/Deque` | ` https://developer.android.com/reference/java/util/Deque#reversed()() ` Returns a reverse-ordered [view](https://developer.android.com/reference/java/util/concurrent/Collection#view) of this collection. | | ` abstract int` | ` https://developer.android.com/reference/java/util/Deque#size()() ` Returns the number of elements in this deque. | || | From interface ` https://developer.android.com/reference/java/util/SequencedCollection ` |---|---| | ` default void` | ` https://developer.android.com/reference/java/util/SequencedCollection#addFirst(E)(E e) ` Adds an element as the first element of this collection (optional operation). | | ` default void` | ` https://developer.android.com/reference/java/util/SequencedCollection#addLast(E)(E e) ` Adds an element as the last element of this collection (optional operation). | | ` default E` | ` https://developer.android.com/reference/java/util/SequencedCollection#getFirst()() ` Gets the first element of this collection. | | ` default E` | ` https://developer.android.com/reference/java/util/SequencedCollection#getLast()() ` Gets the last element of this collection. | | ` default E` | ` https://developer.android.com/reference/java/util/SequencedCollection#removeFirst()() ` Removes and returns the first element of this collection (optional operation). | | ` default E` | ` https://developer.android.com/reference/java/util/SequencedCollection#removeLast()() ` Removes and returns the last element of this collection (optional operation). | | ` abstract https://developer.android.com/reference/java/util/SequencedCollection` | ` https://developer.android.com/reference/java/util/SequencedCollection#reversed()() ` Returns a reverse-ordered [view](https://developer.android.com/reference/java/util/concurrent/Collection#view) of this collection. | || ## Public constructors ### LinkedBlockingDeque Added in [API level 9](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels) ``` public LinkedBlockingDeque () ``` Creates a `LinkedBlockingDeque` with a capacity of `https://developer.android.com/reference/java/lang/Integer#MAX_VALUE`.
### LinkedBlockingDeque Added in [API level 9](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels) ``` public LinkedBlockingDeque (int capacity) ``` Creates a `LinkedBlockingDeque` with the given (fixed) capacity.
| Parameters || |---|---| | `capacity` | `int`: the capacity of this deque
| | Throws || |---|---| | `https://developer.android.com/reference/java/lang/IllegalArgumentException` | if `capacity` is less than 1 | ### LinkedBlockingDeque Added in [API level 9](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels) ``` public LinkedBlockingDeque (Collection c) ``` Creates a `LinkedBlockingDeque` with a capacity of `https://developer.android.com/reference/java/lang/Integer#MAX_VALUE`, initially containing the elements of the given collection, added in traversal order of the collection's iterator.
| Parameters || |---|---| | `c` | `Collection`: the collection of elements to initially contain
| | Throws || |---|---| | `https://developer.android.com/reference/java/lang/NullPointerException` | if the specified collection or any of its elements are null | ## Public methods ### add Added in [API level 9](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels) ``` 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 `https://developer.android.com/reference/java/util/concurrent/LinkedBlockingDeque#offer(E)`. This method is equivalent to `https://developer.android.com/reference/java/util/concurrent/LinkedBlockingDeque#addLast(E)`.
| Parameters || |---|---| | `e` | `E`: the element to add
| | Returns || |---|---| | `boolean` | `true` (as specified by `https://developer.android.com/reference/java/util/Collection#add(E)`)
| | Throws || |---|---| | `https://developer.android.com/reference/java/lang/IllegalStateException` | if this deque is full | | `https://developer.android.com/reference/java/lang/NullPointerException` | if the specified element is null | ### addAll Added in [API level 9](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels) ``` public boolean addAll (Collection 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`.
| Parameters || |---|---| | `c` | `Collection`: the elements to be inserted into this deque
| | Returns || |---|---| | `boolean` | `true` if this deque changed as a result of the call
| | Throws || |---|---| | `https://developer.android.com/reference/java/lang/IllegalArgumentException` | if the collection is this deque | | `https://developer.android.com/reference/java/lang/IllegalStateException` | if this deque is full | | `https://developer.android.com/reference/java/lang/NullPointerException` | if the specified collection or any of its elements are null | **See also:** - `https://developer.android.com/reference/java/util/concurrent/LinkedBlockingDeque#add(E)` ### addFirst Added in [API level 9](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels) ``` public 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 `IllegalStateException` if no space is currently available. When using a capacity-restricted deque, it is generally preferable to use `https://developer.android.com/reference/java/util/concurrent/BlockingDeque#offerFirst(E)`.
| Parameters || |---|---| | `e` | `E`: the element to add
| | Throws || |---|---| | `https://developer.android.com/reference/java/lang/IllegalStateException` | if this deque is full | | `https://developer.android.com/reference/java/lang/NullPointerException` | | ### addLast Added in [API level 9](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels) ``` public 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 `IllegalStateException` if no space is currently available. When using a capacity-restricted deque, it is generally preferable to use `https://developer.android.com/reference/java/util/concurrent/BlockingDeque#offerLast(E)`.
| Parameters || |---|---| | `e` | `E`: the element to add
| | Throws || |---|---| | `https://developer.android.com/reference/java/lang/IllegalStateException` | if this deque is full | | `https://developer.android.com/reference/java/lang/NullPointerException` | | ### clear Added in [API level 9](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels) ``` public void clear () ``` Atomically removes all of the elements from this deque. The deque will be empty after this call returns.
### contains Added in [API level 9](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels) ``` 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)`.
| Parameters || |---|---| | `o` | `Object`: object to be checked for containment in this deque
| | Returns || |---|---| | `boolean` | `true` if this deque contains the specified element
| ### descendingIterator Added in [API level 9](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels) ``` public Iterator 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*](https://developer.android.com/reference/java/util/concurrent/package-summary#Weakly).
| Returns || |---|---| | `https://developer.android.com/reference/java/util/Iterator` | an iterator over the elements in this deque in reverse order
| ### drainTo Added in [API level 9](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels) ``` public int drainTo (Collection c, int maxElements) ``` 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.
| Parameters || |---|---| | `c` | `Collection`: the collection to transfer elements into
| | `maxElements` | `int`: the maximum number of elements to transfer
| | Returns || |---|---| | `int` | the number of elements transferred
| | Throws || |---|---| | `https://developer.android.com/reference/java/lang/ClassCastException` | | | `https://developer.android.com/reference/java/lang/IllegalArgumentException` | | | `https://developer.android.com/reference/java/lang/NullPointerException` | | | `https://developer.android.com/reference/java/lang/UnsupportedOperationException` | | ### drainTo Added in [API level 9](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels) ``` public int drainTo (Collection c) ``` 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.
| Parameters || |---|---| | `c` | `Collection`: the collection to transfer elements into
| | Returns || |---|---| | `int` | the number of elements transferred
| | Throws || |---|---| | `https://developer.android.com/reference/java/lang/ClassCastException` | | | `https://developer.android.com/reference/java/lang/IllegalArgumentException` | | | `https://developer.android.com/reference/java/lang/NullPointerException` | | | `https://developer.android.com/reference/java/lang/UnsupportedOperationException` | | ### element Added in [API level 9](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels) ``` public E element () ``` Retrieves, but does not remove, the head of the queue represented by this deque. This method differs from `https://developer.android.com/reference/java/util/concurrent/LinkedBlockingDeque#peek()` only in that it throws an exception if this deque is empty. This method is equivalent to `https://developer.android.com/reference/java/util/concurrent/LinkedBlockingDeque#getFirst()`.
| Returns || |---|---| | `E` | the head of the queue represented by this deque
| | Throws || |---|---| | `https://developer.android.com/reference/java/util/NoSuchElementException` | if this deque is empty | ### forEach Added in [API level 24](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels) ``` public void forEach (Consumer action) ```

| Parameters || |---|---| | `action` | `Consumer`
| | Throws || |---|---| | `https://developer.android.com/reference/java/lang/NullPointerException` | | ### getFirst Added in [API level 9](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels) ``` public E getFirst () ``` Retrieves, but does not remove, the first element of this deque. This method differs from `https://developer.android.com/reference/java/util/Deque#peekFirst()` only in that it throws an exception if this deque is empty.
| Returns || |---|---| | `E` | the head of this deque
| | Throws || |---|---| | `https://developer.android.com/reference/java/util/NoSuchElementException` | | ### getLast Added in [API level 9](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels) ``` public E getLast () ``` Retrieves, but does not remove, the last element of this deque. This method differs from `https://developer.android.com/reference/java/util/Deque#peekLast()` only in that it throws an exception if this deque is empty.
| Returns || |---|---| | `E` | the tail of this deque
| | Throws || |---|---| | `https://developer.android.com/reference/java/util/NoSuchElementException` | | ### iterator Added in [API level 9](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels) ``` public Iterator 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*](https://developer.android.com/reference/java/util/concurrent/package-summary#Weakly).
| Returns || |---|---| | `https://developer.android.com/reference/java/util/Iterator` | an iterator over the elements in this deque in proper sequence
| ### offer Added in [API level 9](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels) ``` public 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. This method is equivalent to `https://developer.android.com/reference/java/util/concurrent/BlockingDeque#offerLast(E,%20long,%20java.util.concurrent.TimeUnit)`.
| Parameters || |---|---| | `e` | `E`: the element to add
| | `timeout` | `long`: how long to wait before giving up, in units of `unit`
| | `unit` | `TimeUnit`: a `TimeUnit` determining how to interpret the `timeout` parameter
| | Returns || |---|---| | `boolean` | `true` if the element was added to this deque, else `false`
| | Throws || |---|---| | `https://developer.android.com/reference/java/lang/InterruptedException` | | | `https://developer.android.com/reference/java/lang/NullPointerException` | | ### offer Added in [API level 9](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels) ``` public 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 `true` upon success and `false` if no space is currently available. When using a capacity-restricted deque, this method is generally preferable to the `https://developer.android.com/reference/java/util/concurrent/BlockingDeque#add(E)` method, which can fail to insert an element only by throwing an exception. This method is equivalent to `https://developer.android.com/reference/java/util/concurrent/BlockingDeque#offerLast(E)`.
| Parameters || |---|---| | `e` | `E`: the element to add
| | Returns || |---|---| | `boolean` | `true` if the element was added to this deque, else `false`
| | Throws || |---|---| | `https://developer.android.com/reference/java/lang/NullPointerException` | if the specified element is null | ### offerFirst Added in [API level 9](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels) ``` public 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 `true` upon success and `false` if no space is currently available. When using a capacity-restricted deque, this method is generally preferable to the `https://developer.android.com/reference/java/util/concurrent/BlockingDeque#addFirst(E)` method, which can fail to insert an element only by throwing an exception.
| Parameters || |---|---| | `e` | `E`: the element to add
| | Returns || |---|---| | `boolean` | `true` if the element was added to this deque, else `false`
| | Throws || |---|---| | `https://developer.android.com/reference/java/lang/NullPointerException` | | ### offerFirst Added in [API level 9](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels) ``` public 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.
| Parameters || |---|---| | `e` | `E`: the element to add
| | `timeout` | `long`: how long to wait before giving up, in units of `unit`
| | `unit` | `TimeUnit`: a `TimeUnit` determining how to interpret the `timeout` parameter
| | Returns || |---|---| | `boolean` | `true` if successful, or `false` if the specified waiting time elapses before space is available
| | Throws || |---|---| | `https://developer.android.com/reference/java/lang/InterruptedException` | | | `https://developer.android.com/reference/java/lang/NullPointerException` | | ### offerLast Added in [API level 9](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels) ``` public 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 `true` upon success and `false` if no space is currently available. When using a capacity-restricted deque, this method is generally preferable to the `https://developer.android.com/reference/java/util/concurrent/BlockingDeque#addLast(E)` method, which can fail to insert an element only by throwing an exception.
| Parameters || |---|---| | `e` | `E`: the element to add
| | Returns || |---|---| | `boolean` | `true` if the element was added to this deque, else `false`
| | Throws || |---|---| | `https://developer.android.com/reference/java/lang/NullPointerException` | | ### offerLast Added in [API level 9](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels) ``` public 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.
| Parameters || |---|---| | `e` | `E`: the element to add
| | `timeout` | `long`: how long to wait before giving up, in units of `unit`
| | `unit` | `TimeUnit`: a `TimeUnit` determining how to interpret the `timeout` parameter
| | Returns || |---|---| | `boolean` | `true` if successful, or `false` if the specified waiting time elapses before space is available
| | Throws || |---|---| | `https://developer.android.com/reference/java/lang/InterruptedException` | | | `https://developer.android.com/reference/java/lang/NullPointerException` | | ### peek Added in [API level 9](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels) ``` public E peek () ``` Retrieves, but does not remove, 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 `https://developer.android.com/reference/java/util/Deque#peekFirst()`.
| Returns || |---|---| | `E` | the head of this deque, or `null` if this deque is empty
| ### peekFirst Added in [API level 9](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels) ``` public E peekFirst () ``` Retrieves, but does not remove, the first element of this deque, or returns `null` if this deque is empty.
| Returns || |---|---| | `E` | the head of this deque, or `null` if this deque is empty
| ### peekLast Added in [API level 9](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels) ``` public E peekLast () ``` Retrieves, but does not remove, the last element of this deque, or returns `null` if this deque is empty.
| Returns || |---|---| | `E` | the tail of this deque, or `null` if this deque is empty
| ### poll Added in [API level 9](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels) ``` public E poll (long timeout, TimeUnit unit) ``` Retrieves and removes the head of the queue represented by this deque (in other words, the first element of this deque), waiting up to the specified wait time if necessary for an element to become available. This method is equivalent to `https://developer.android.com/reference/java/util/concurrent/BlockingDeque#pollFirst(long,%20java.util.concurrent.TimeUnit)`.
| Parameters || |---|---| | `timeout` | `long`: how long to wait before giving up, in units of `unit`
| | `unit` | `TimeUnit`: a `TimeUnit` determining how to interpret the `timeout` parameter
| | Returns || |---|---| | `E` | the head of this deque, or `null` if the specified waiting time elapses before an element is available
| | Throws || |---|---| | `https://developer.android.com/reference/java/lang/InterruptedException` | | ### poll Added in [API level 9](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels) ``` public E poll () ``` 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 `https://developer.android.com/reference/java/util/Deque#pollFirst()`.
| Returns || |---|---| | `E` | the head of this deque, or `null` if this deque is empty
| ### pollFirst Added in [API level 9](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels) ``` public E pollFirst () ``` Retrieves and removes the first element of this deque, or returns `null` if this deque is empty.
| Returns || |---|---| | `E` | the head of this deque, or `null` if this deque is empty
| ### pollFirst Added in [API level 9](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels) ``` public E pollFirst (long timeout, TimeUnit unit) ``` Retrieves and removes the first element of this deque, waiting up to the specified wait time if necessary for an element to become available.
| Parameters || |---|---| | `timeout` | `long`: how long to wait before giving up, in units of `unit`
| | `unit` | `TimeUnit`: a `TimeUnit` determining how to interpret the `timeout` parameter
| | Returns || |---|---| | `E` | the head of this deque, or `null` if the specified waiting time elapses before an element is available
| | Throws || |---|---| | `https://developer.android.com/reference/java/lang/InterruptedException` | | ### pollLast Added in [API level 9](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels) ``` public E pollLast () ``` Retrieves and removes the last element of this deque, or returns `null` if this deque is empty.
| Returns || |---|---| | `E` | the tail of this deque, or `null` if this deque is empty
| ### pollLast Added in [API level 9](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels) ``` public E pollLast (long timeout, TimeUnit unit) ``` Retrieves and removes the last element of this deque, waiting up to the specified wait time if necessary for an element to become available.
| Parameters || |---|---| | `timeout` | `long`: how long to wait before giving up, in units of `unit`
| | `unit` | `TimeUnit`: a `TimeUnit` determining how to interpret the `timeout` parameter
| | Returns || |---|---| | `E` | the tail of this deque, or `null` if the specified waiting time elapses before an element is available
| | Throws || |---|---| | `https://developer.android.com/reference/java/lang/InterruptedException` | | ### pop Added in [API level 9](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels) ``` public E pop () ``` 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 `https://developer.android.com/reference/java/util/Deque#removeFirst()`.
| Returns || |---|---| | `E` | the element at the front of this deque (which is the top of the stack represented by this deque)
| | Throws || |---|---| | `https://developer.android.com/reference/java/util/NoSuchElementException` | | ### push Added in [API level 9](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels) ``` public 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 `IllegalStateException` if no space is currently available. This method is equivalent to `https://developer.android.com/reference/java/util/concurrent/BlockingDeque#addFirst(E)`.
| Parameters || |---|---| | `e` | `E`: the element to push
| | Throws || |---|---| | `https://developer.android.com/reference/java/lang/IllegalStateException` | if this deque is full | | `https://developer.android.com/reference/java/lang/NullPointerException` | | ### put Added in [API level 9](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels) ``` public 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. This method is equivalent to `https://developer.android.com/reference/java/util/concurrent/BlockingDeque#putLast(E)`.
| Parameters || |---|---| | `e` | `E`: the element to add
| | Throws || |---|---| | `https://developer.android.com/reference/java/lang/InterruptedException` | | | `https://developer.android.com/reference/java/lang/NullPointerException` | | ### putFirst Added in [API level 9](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels) ``` public void putFirst (E e) ``` Inserts the specified element at the front of this deque, waiting if necessary for space to become available.
| Parameters || |---|---| | `e` | `E`: the element to add
| | Throws || |---|---| | `https://developer.android.com/reference/java/lang/InterruptedException` | | | `https://developer.android.com/reference/java/lang/NullPointerException` | | ### putLast Added in [API level 9](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels) ``` public void putLast (E e) ``` Inserts the specified element at the end of this deque, waiting if necessary for space to become available.
| Parameters || |---|---| | `e` | `E`: the element to add
| | Throws || |---|---| | `https://developer.android.com/reference/java/lang/InterruptedException` | | | `https://developer.android.com/reference/java/lang/NullPointerException` | | ### remainingCapacity Added in [API level 9](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels) ``` 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.
| Returns || |---|---| | `int` | the remaining capacity
| ### remove Added in [API level 9](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels) ``` 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 `https://developer.android.com/reference/java/util/concurrent/LinkedBlockingDeque#removeFirstOccurrence(java.lang.Object)`.
| Parameters || |---|---| | `o` | `Object`: element to be removed from this deque, if present
| | Returns || |---|---| | `boolean` | `true` if this deque changed as a result of the call
| ### remove Added in [API level 9](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels) ``` public E remove () ``` Retrieves and removes the head of the queue represented by this deque. This method differs from `https://developer.android.com/reference/java/util/concurrent/LinkedBlockingDeque#poll()` only in that it throws an exception if this deque is empty. This method is equivalent to `https://developer.android.com/reference/java/util/concurrent/LinkedBlockingDeque#removeFirst()`.
| Returns || |---|---| | `E` | the head of the queue represented by this deque
| | Throws || |---|---| | `https://developer.android.com/reference/java/util/NoSuchElementException` | if this deque is empty | ### removeAll Added in [API level 9](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels) ``` public boolean removeAll (Collection c) ``` 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.
| Parameters || |---|---| | `c` | `Collection`: collection containing elements to be removed from this collection
| | Returns || |---|---| | `boolean` | `true` if this collection changed as a result of the call
| | Throws || |---|---| | `https://developer.android.com/reference/java/lang/NullPointerException` | | ### removeFirst Added in [API level 9](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels) ``` public E removeFirst () ``` Retrieves and removes the first element of this deque. This method differs from `https://developer.android.com/reference/java/util/Deque#pollFirst()` only in that it throws an exception if this deque is empty.
| Returns || |---|---| | `E` | the head of this deque
| | Throws || |---|---| | `https://developer.android.com/reference/java/util/NoSuchElementException` | | ### removeFirstOccurrence Added in [API level 9](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels) ``` public boolean removeFirstOccurrence (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).
| Parameters || |---|---| | `o` | `Object`: element to be removed from this deque, if present
| | Returns || |---|---| | `boolean` | `true` if an element was removed as a result of this call
| ### removeIf Added in [API level 24](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels) ``` public boolean removeIf (Predicate filter) ``` Removes all of the elements of this collection that satisfy the given predicate (optional operation). Errors or runtime exceptions thrown during iteration or by the predicate are relayed to the caller.
| Parameters || |---|---| | `filter` | `Predicate`: a predicate which returns `true` for elements to be removed
| | Returns || |---|---| | `boolean` | `true` if any elements were removed
| | Throws || |---|---| | `https://developer.android.com/reference/java/lang/NullPointerException` | | ### removeLast Added in [API level 9](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels) ``` public E removeLast () ``` Retrieves and removes the last element of this deque. This method differs from `https://developer.android.com/reference/java/util/Deque#pollLast()` only in that it throws an exception if this deque is empty.
| Returns || |---|---| | `E` | the tail of this deque
| | Throws || |---|---| | `https://developer.android.com/reference/java/util/NoSuchElementException` | | ### removeLastOccurrence Added in [API level 9](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels) ``` public boolean removeLastOccurrence (Object o) ``` Removes the last occurrence of the specified element from this deque. 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).
| Parameters || |---|---| | `o` | `Object`: element to be removed from this deque, if present
| | Returns || |---|---| | `boolean` | `true` if an element was removed as a result of this call
| ### retainAll Added in [API level 9](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels) ``` public boolean retainAll (Collection c) ``` 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.
| Parameters || |---|---| | `c` | `Collection`: collection containing elements to be retained in this collection
| | Returns || |---|---| | `boolean` | `true` if this collection changed as a result of the call
| | Throws || |---|---| | `https://developer.android.com/reference/java/lang/NullPointerException` | | ### size Added in [API level 9](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels) ``` public int size () ``` Returns the number of elements in this deque.
| Returns || |---|---| | `int` | the number of elements in this deque
| ### spliterator Added in [API level 24](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels) ``` public Spliterator spliterator () ``` Returns a `https://developer.android.com/reference/java/util/Spliterator` over the elements in this deque. The returned spliterator is [*weakly consistent*](https://developer.android.com/reference/java/util/concurrent/package-summary#Weakly). The `Spliterator` reports `https://developer.android.com/reference/java/util/Spliterator#CONCURRENT`, `https://developer.android.com/reference/java/util/Spliterator#ORDERED`, and `https://developer.android.com/reference/java/util/Spliterator#NONNULL`.
##### Implementation Note: - The `Spliterator` implements `trySplit` to permit limited parallelism. | Returns || |---|---| | `https://developer.android.com/reference/java/util/Spliterator` | a `Spliterator` over the elements in this deque
| ### take Added in [API level 9](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels) ``` public E take () ``` Retrieves and removes the head of the queue represented by this deque (in other words, the first element of this deque), waiting if necessary until an element becomes available. This method is equivalent to `https://developer.android.com/reference/java/util/concurrent/BlockingDeque#takeFirst()`.
| Returns || |---|---| | `E` | the head of this deque
| | Throws || |---|---| | `https://developer.android.com/reference/java/lang/InterruptedException` | | ### takeFirst Added in [API level 9](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels) ``` public E takeFirst () ``` Retrieves and removes the first element of this deque, waiting if necessary until an element becomes available.
| Returns || |---|---| | `E` | the head of this deque
| | Throws || |---|---| | `https://developer.android.com/reference/java/lang/InterruptedException` | | ### takeLast Added in [API level 9](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels) ``` public E takeLast () ``` Retrieves and removes the last element of this deque, waiting if necessary until an element becomes available.
| Returns || |---|---| | `E` | the tail of this deque
| | Throws || |---|---| | `https://developer.android.com/reference/java/lang/InterruptedException` | | ### toArray Added in [API level 9](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels) ``` 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.
| Returns || |---|---| | `https://developer.android.com/reference/java/lang/Object` | an array containing all of the elements in this deque
| ### toArray Added in [API level 9](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels) ``` public 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 `https://developer.android.com/reference/java/util/concurrent/LinkedBlockingDeque#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()`.

| Parameters || |---|---| | `a` | `T`: 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 || |---|---| | `T[]` | an array containing all of the elements in this deque
| | Throws || |---|---| | `https://developer.android.com/reference/java/lang/ArrayStoreException` | if the runtime type of the specified array is not a supertype of the runtime type of every element in this deque | | `https://developer.android.com/reference/java/lang/NullPointerException` | if the specified array is null | ### toString Added in [API level 9](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels) ``` public String toString () ``` Returns a string representation of this collection. The string representation consists of a list of the collection'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 `https://developer.android.com/reference/java/lang/String#valueOf(java.lang.Object)`.
| Returns || |---|---| | `https://developer.android.com/reference/java/lang/String` | a string representation of this collection
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