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org.compass.core.util.backport.java.util.concurrent
Class LinkedBlockingDeque

java.lang.Object
  extended by java.util.AbstractCollection
      extended by org.compass.core.util.backport.java.util.AbstractCollection
          extended by org.compass.core.util.backport.java.util.AbstractQueue
              extended by org.compass.core.util.backport.java.util.concurrent.LinkedBlockingDeque
All Implemented Interfaces:
Serializable, Iterable, Collection, BlockingDeque, BlockingQueue, Deque, Queue
public class LinkedBlockingDeque
extends AbstractQueue
implements BlockingDeque, 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
Author:
Doug Lea
See Also:
Serialized Form

Nested Class Summary
(package private) static class LinkedBlockingDeque.Node
          Doubly-linked list node class
 
Constructor Summary
LinkedBlockingDeque()
          Creates a LinkedBlockingDeque with a capacity of Integer.MAX_VALUE.
LinkedBlockingDeque(Collection 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.
LinkedBlockingDeque(int capacity)
          Creates a LinkedBlockingDeque with the given (fixed) capacity.
 
Method Summary
 boolean add(Object e)
          Inserts the specified element at the end of this deque unless it would violate capacity restrictions.
 void addFirst(Object 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 addLast(Object 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 clear()
          Atomically removes all of the elements from this deque.
 boolean contains(Object o)
          Returns true if this deque contains the specified element.
 Iterator descendingIterator()
          Returns an iterator over the elements in this deque in reverse sequential order.
 int drainTo(Collection c)
          Removes all available elements from this queue and adds them to the given collection.
 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.
 Object element()
          Retrieves, but does not remove, the head of the queue represented by this deque.
 Object getFirst()
          Retrieves, but does not remove, the first element of this deque.
 Object getLast()
          Retrieves, but does not remove, the last element of this deque.
 Iterator iterator()
          Returns an iterator over the elements in this deque in proper sequence.
 boolean offer(Object 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 offer(Object 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(Object 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 offerFirst(Object 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(Object 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 offerLast(Object 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.
 Object 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.
 Object peekFirst()
          Retrieves, but does not remove, the first element of this deque, or returns null if this deque is empty.
 Object peekLast()
          Retrieves, but does not remove, the last element of this deque, or returns null if this deque is empty.
 Object 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.
 Object 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.
 Object pollFirst()
          Retrieves and removes the first element of this deque, or returns null if this deque is empty.
 Object 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.
 Object pollLast()
          Retrieves and removes the last element of this deque, or returns null if this deque is empty.
 Object 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.
 Object pop()
          Pops an element from the stack represented by this deque.
 void push(Object e)
          Pushes an element onto the stack represented by this deque.
 void put(Object 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(Object e)
          Inserts the specified element at the front of this deque, waiting if necessary for space to become available.
 void putLast(Object 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.
 Object 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.
 Object removeFirst()
          Retrieves and removes the first element of this deque.
 boolean removeFirstOccurrence(Object o)
          Removes the first occurrence of the specified element from this deque.
 Object removeLast()
          Retrieves and removes the last element of this deque.
 boolean removeLastOccurrence(Object o)
          Removes the last occurrence of the specified element from this deque.
(package private)  boolean removeNode(LinkedBlockingDeque.Node e)
          Variant of removeFirstOccurrence needed by iterator.remove.
 int size()
          Returns the number of elements in this deque.
 Object 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.
 Object takeFirst()
          Retrieves and removes the first element of this deque, waiting if necessary until an element becomes available.
 Object takeLast()
          Retrieves and removes the last element of this deque, waiting if necessary until an element becomes available.
 Object[] toArray()
          Returns an array containing all of the elements in this deque, in proper sequence (from first to last element).
 Object[] toArray(Object[] 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.
 String toString()
           
 
Methods inherited from class org.compass.core.util.backport.java.util.AbstractQueue
addAll
 
Methods inherited from class java.util.AbstractCollection
containsAll, isEmpty, removeAll, retainAll
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait
 
Methods inherited from interface java.util.Collection
addAll, containsAll, equals, hashCode, isEmpty, removeAll, retainAll
 
Methods inherited from interface java.util.Collection
addAll, containsAll, equals, hashCode, isEmpty, removeAll, retainAll
 

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 - if capacity is less than 1

LinkedBlockingDeque

public LinkedBlockingDeque(Collection 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(Object 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 interface BlockingDeque
Specified by:
addFirst in interface Deque
Parameters:
e - the element to add
Throws:
IllegalStateException - if the element cannot be added at this time due to capacity restrictions
NullPointerException - if the specified element is null

addLast

public void addLast(Object 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 interface BlockingDeque
Specified by:
addLast in interface Deque
Parameters:
e - the element to add
Throws:
IllegalStateException - if the element cannot be added at this time due to capacity restrictions
NullPointerException - if the specified element is null

offerFirst

public boolean offerFirst(Object 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 interface BlockingDeque
Specified by:
offerFirst in interface Deque
Parameters:
e - the element to add
Returns:
true if the element was added to this deque, else false
Throws:
NullPointerException - if the specified element is null

offerLast

public boolean offerLast(Object 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 interface BlockingDeque
Specified by:
offerLast in interface Deque
Parameters:
e - the element to add
Returns:
true if the element was added to this deque, else false
Throws:
NullPointerException - if the specified element is null

putFirst

public void putFirst(Object 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 interface BlockingDeque
Parameters:
e - the element to add
Throws:
NullPointerException - if the specified element is null
InterruptedException - if interrupted while waiting

putLast

public void putLast(Object 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 interface BlockingDeque
Parameters:
e - the element to add
Throws:
NullPointerException - if the specified element is null
InterruptedException - if interrupted while waiting

offerFirst

public boolean offerFirst(Object 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 interface BlockingDeque
Parameters:
e - the element to add
timeout - how long to wait before giving up, in units of unit
unit - a TimeUnit determining how to interpret the timeout parameter
Returns:
true if successful, or false 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(Object 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 interface BlockingDeque
Parameters:
e - the element to add
timeout - how long to wait before giving up, in units of unit
unit - a TimeUnit determining how to interpret the timeout parameter
Returns:
true if successful, or false 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 Object 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 interface Deque
Returns:
the head of this deque
Throws:
NoSuchElementException

removeLast

public Object 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 interface Deque
Returns:
the tail of this deque
Throws:
NoSuchElementException

pollFirst

public Object pollFirst()
Description copied from interface: Deque
Retrieves and removes the first element of this deque, or returns null if this deque is empty.

Specified by:
pollFirst in interface Deque
Returns:
the head of this deque, or null if this deque is empty

pollLast

public Object pollLast()
Description copied from interface: Deque
Retrieves and removes the last element of this deque, or returns null if this deque is empty.

Specified by:
pollLast in interface Deque
Returns:
the tail of this deque, or null if this deque is empty

takeFirst

public Object takeFirst()
                 throws InterruptedException
Description copied from interface: BlockingDeque
Retrieves and removes the first element of this deque, waiting if necessary until an element becomes available.

Specified by:
takeFirst in interface BlockingDeque
Returns:
the head of this deque
Throws:
InterruptedException - if interrupted while waiting

takeLast

public Object takeLast()
                throws InterruptedException
Description copied from interface: BlockingDeque
Retrieves and removes the last element of this deque, waiting if necessary until an element becomes available.

Specified by:
takeLast in interface BlockingDeque
Returns:
the tail of this deque
Throws:
InterruptedException - if interrupted while waiting

pollFirst

public Object pollFirst(long timeout,
                        TimeUnit unit)
                 throws InterruptedException
Description copied from interface: BlockingDeque
Retrieves and removes the first element of this deque, waiting up to the specified wait time if necessary for an element to become available.

Specified by:
pollFirst in interface BlockingDeque
Parameters:
timeout - how long to wait before giving up, in units of unit
unit - a TimeUnit determining how to interpret the timeout parameter
Returns:
the head of this deque, or null if the specified waiting time elapses before an element is available
Throws:
InterruptedException - if interrupted while waiting

pollLast

public Object pollLast(long timeout,
                       TimeUnit unit)
                throws InterruptedException
Description copied from interface: BlockingDeque
Retrieves and removes the last element of this deque, waiting up to the specified wait time if necessary for an element to become available.

Specified by:
pollLast in interface BlockingDeque
Parameters:
timeout - how long to wait before giving up, in units of unit
unit - a TimeUnit determining how to interpret the timeout parameter
Returns:
the tail of this deque, or null if the specified waiting time elapses before an element is available
Throws:
InterruptedException - if interrupted while waiting

getFirst

public Object 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 interface Deque
Returns:
the head of this deque
Throws:
NoSuchElementException

getLast

public Object 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 interface Deque
Returns:
the tail of this deque
Throws:
NoSuchElementException

peekFirst

public Object peekFirst()
Description copied from interface: Deque
Retrieves, but does not remove, the first element of this deque, or returns null if this deque is empty.

Specified by:
peekFirst in interface Deque
Returns:
the head of this deque, or null if this deque is empty

peekLast

public Object peekLast()
Description copied from interface: Deque
Retrieves, but does not remove, the last element of this deque, or returns null if this deque is empty.

Specified by:
peekLast in interface Deque
Returns:
the tail of this deque, or null if this deque is empty

removeFirstOccurrence

public boolean removeFirstOccurrence(Object o)
Description copied from interface: BlockingDeque
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).

Specified by:
removeFirstOccurrence in interface BlockingDeque
Specified by:
removeFirstOccurrence in interface Deque
Parameters:
o - element to be removed from this deque, if present
Returns:
true if an element was removed as a result of this call

removeLastOccurrence

public boolean removeLastOccurrence(Object o)
Description copied from interface: BlockingDeque
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).

Specified by:
removeLastOccurrence in interface BlockingDeque
Specified by:
removeLastOccurrence in interface Deque
Parameters:
o - element to be removed from this deque, if present
Returns:
true if an element was removed as a result of this call

add

public boolean add(Object 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(java.lang.Object).

Specified by:
add in interface Collection
Specified by:
add in interface BlockingDeque
Specified by:
add in interface BlockingQueue
Specified by:
add in interface Deque
Specified by:
add in interface Queue
Overrides:
add in class AbstractQueue
Parameters:
e - the element to add
Returns:
true (as specified by Collection.add(E))
Throws:
IllegalStateException - if the element cannot be added at this time due to capacity restrictions
NullPointerException - if the specified element is null

offer

public boolean offer(Object 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(java.lang.Object) method, which can fail to insert an element only by throwing an exception.

This method is equivalent to offerLast.

Specified by:
offer in interface BlockingDeque
Specified by:
offer in interface BlockingQueue
Specified by:
offer in interface Deque
Specified by:
offer in interface Queue
Parameters:
e - the element to add
Returns:
true if the element was added to this queue, else false
Throws:
NullPointerException - if the specified element is null

put

public void put(Object 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 interface BlockingDeque
Specified by:
put in interface BlockingQueue
Parameters:
e - the element to add
Throws:
NullPointerException - if the specified element is null
InterruptedException - if interrupted while waiting

offer

public boolean offer(Object 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 interface BlockingDeque
Specified by:
offer in interface BlockingQueue
Parameters:
e - the element to add
timeout - how long to wait before giving up, in units of unit
unit - a TimeUnit determining how to interpret the timeout parameter
Returns:
true if the element was added to this deque, else false
Throws:
NullPointerException - if the specified element is null
InterruptedException - if interrupted while waiting

remove

public Object 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 interface BlockingDeque
Specified by:
remove in interface Deque
Specified by:
remove in interface Queue
Overrides:
remove in class AbstractQueue
Returns:
the head of the queue represented by this deque
Throws:
NoSuchElementException - if this deque is empty

poll

public Object poll()
Description copied from interface: BlockingDeque
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 Deque.pollFirst().

Specified by:
poll in interface BlockingDeque
Specified by:
poll in interface Deque
Specified by:
poll in interface Queue
Returns:
the head of this deque, or null if this deque is empty

take

public Object take()
            throws InterruptedException
Description copied from interface: BlockingDeque
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 takeFirst.

Specified by:
take in interface BlockingDeque
Specified by:
take in interface BlockingQueue
Returns:
the head of this deque
Throws:
InterruptedException - if interrupted while waiting

poll

public Object poll(long timeout,
                   TimeUnit unit)
            throws InterruptedException
Description copied from interface: BlockingDeque
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 pollFirst.

Specified by:
poll in interface BlockingDeque
Specified by:
poll in interface BlockingQueue
Parameters:
timeout - how long to wait before giving up, in units of unit
unit - a TimeUnit determining how to interpret the timeout parameter
Returns:
the head of this deque, or null if the specified waiting time elapses before an element is available
Throws:
InterruptedException - if interrupted while waiting

element

public Object 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 interface BlockingDeque
Specified by:
element in interface Deque
Specified by:
element in interface Queue
Overrides:
element in class AbstractQueue
Returns:
the head of the queue represented by this deque
Throws:
NoSuchElementException - if this deque is empty

peek

public Object peek()
Description copied from interface: BlockingDeque
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 peekFirst.

Specified by:
peek in interface BlockingDeque
Specified by:
peek in interface Deque
Specified by:
peek in interface Queue
Returns:
the head of this deque, or null 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 interface BlockingQueue
Returns:
the remaining capacity

drainTo

public int drainTo(Collection 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 interface BlockingQueue
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 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 interface BlockingQueue
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(Object e)
Description copied from interface: BlockingDeque
Pushes an element onto the stack represented by this deque. In other words, inserts the element at the front of this deque unless it would violate capacity restrictions.

This method is equivalent to addFirst.

Specified by:
push in interface BlockingDeque
Specified by:
push in interface Deque
Parameters:
e - the element to push
Throws:
IllegalStateException - if the element cannot be added at this time due to capacity restrictions
NullPointerException - if the specified element is null

pop

public Object 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 interface Deque
Returns:
the element at the front of this deque (which is the top of the stack represented by this deque)
Throws:
NoSuchElementException

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 interface Collection
Specified by:
remove in interface BlockingDeque
Specified by:
remove in interface BlockingQueue
Specified by:
remove in interface Deque
Overrides:
remove in class AbstractCollection
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: