decaf::util::concurrent::SynchronousQueue< E > Class Template Reference

A blocking queue in which each insert operation must wait for a corresponding remove operation by another thread, and vice versa. More...

#include <src/main/decaf/util/concurrent/SynchronousQueue.h>

Inheritance diagram for decaf::util::concurrent::SynchronousQueue< E >:

Data Structures
class	EmptyIterator

Public Member Functions
	SynchronousQueue ()
virtual	~SynchronousQueue ()
virtual void	put (const E &value)
	Adds the specified element to this queue, waiting if necessary for another thread to receive it.
virtual bool	offer (const E &e, long long timeout, const TimeUnit &unit)
	Inserts the specified element into this queue, waiting if necessary up to the specified wait time for another thread to receive it.
virtual bool	offer (const E &value)
	Inserts the specified element into this queue, if another thread is waiting to receive it.
virtual E	take ()
	Retrieves and removes the head of this queue, waiting if necessary for another thread to insert it.
virtual bool	poll (E &result, long long timeout, const TimeUnit &unit)
	Retrieves and removes the head of this queue, waiting if necessary up to the specified wait time, for another thread to insert it.
virtual bool	poll (E &result)
	Retrieves and removes the head of this queue, if another thread is currently making an element available.
virtual bool	equals (const Collection< E > &value) const
	Answers true if this Collection and the one given are the same size and if each element contained in the Collection given is equal to an element contained in this collection.
virtual decaf::util::Iterator < E > *	iterator ()
virtual decaf::util::Iterator < E > *	iterator () const
virtual bool	isEmpty () const
	Returns true if this collection contains no elements.
virtual int	size () const
	Returns the number of elements in this collection.
virtual int	remainingCapacity () const
	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.
virtual void	clear ()
	Removes all of the elements from this collection (optional operation).The collection will be empty after this method returns.This implementation iterates over this collection, removing each element using the Iterator.remove operation. Most implementations will probably choose to override this method for efficiency.Note that this implementation will throw an UnsupportedOperationException if the iterator returned by this collection's iterator method does not implement the remove method and this collection is non-empty. Exceptions UnsupportedOperationException if the clear operation is not supported by this collection This implementation repeatedly invokes poll until it returns false.
virtual bool	contains (const E &value DECAF_UNUSED) const
virtual bool	containsAll (const Collection< E > &collection) const
	Returns true if this collection contains all of the elements in the specified collection. Parameters collection The Collection to compare to this one. Exceptions NullPointerException if the Collection contains pointers and the Collection does not allow for NULL elements (optional check). This implementation iterates over the specified collection, checking each element returned by the iterator in turn to see if it's contained in this collection. If all elements are so contained true is returned, otherwise false.
virtual bool	remove (const E &value DECAF_UNUSED)
virtual bool	removeAll (const Collection< E > &collection DECAF_UNUSED)
virtual bool	retainAll (const Collection< E > &collection DECAF_UNUSED)
virtual bool	peek (E &result DECAF_UNUSED) const
virtual std::vector< E >	toArray () const
	Answers an STL vector containing copies of all elements contained in this Collection.
virtual int	drainTo (Collection< E > &c)
	Removes all available elements from this queue and adds them to the given collection.
virtual int	drainTo (Collection< E > &c, int maxElements)
	Removes at most the given number of available elements from this queue and adds them to the given collection.
Public Member Functions inherited from decaf::util::concurrent::BlockingQueue< E >
virtual	~BlockingQueue ()
Public Member Functions inherited from decaf::util::AbstractQueue< E >
	AbstractQueue ()
virtual	~AbstractQueue ()
virtual bool	add (const E &value)
	Returns true if this collection changed as a result of the call.(Returns false if this collection does not permit duplicates and already contains the specified element.)Collections that support this operation may place limitations on what elements may be added to this collection. In particular, some collections will refuse to add null elements, and others will impose restrictions on the type of elements that may be added. Collection classes should clearly specify in their documentation any restrictions on what elements may be added.If a collection refuses to add a particular element for any reason other than that it already contains the element, it must throw an exception (rather than returning false). This preserves the invariant that a collection always contains the specified element after this call returns.For non-pointer values, i.e. class instances or string's the object will be copied into the collection, thus the object must support being copied, must not hide the copy constructor and assignment operator. Parameters value The reference to the element to add to this Collection. Returns true if the element was added to this Collection. Exceptions UnsupportedOperationExceptio if this is an unmodifiable collection. NullPointerException if the Collection is a container of pointers and does not allow NULL values. IllegalArgumentException if some property of the element prevents it from being added to this collection IllegalStateException if the element cannot be added at this time due to insertion restrictions.
virtual bool	addAll (const Collection< E > &collection)
	Adds all of the elements in the specified collection to this collection.The behavior of this operation is undefined if the specified collection is modified while the operation is in progress. (This implies that the behavior of this call is undefined if the specified collection is this collection, and this collection is nonempty.) Parameters collection The Collection whose elements are added to this one. Returns true if this collection changed as a result of the call Exceptions UnsupportedOperationExceptio if this is an unmodifiable collection. NullPointerException if the Collection is a container of pointers and does not allow NULL values. IllegalArgumentException if some property of an element prevents it from being added to this collection IllegalStateException if an element cannot be added at this time due to insertion restrictions. This implementation iterates over the specified collection, and adds each object returned by the iterator to this collection, in turn.Note that this implementation will throw an UnsupportedOperationException unless add is overridden (assuming the specified collection is non-empty).
virtual E	remove ()
	Gets and removes the element in the head of the queue.Throws a NoSuchElementException if there is no element in the queue. Returns the element in the head of the queue. Exceptions NoSuchElementException if there is no element in the queue.
virtual E	element () const
	Gets but not removes the element in the head of the queue.Throws a NoSuchElementException if there is no element in the queue. Returns the element in the head of the queue. Exceptions NoSuchElementException if there is no element in the queue.
Public Member Functions inherited from decaf::util::Queue< E >
virtual	~Queue ()
virtual bool	peek (E &result) const =0
	Gets but not removes the element in the head of the queue.
Public Member Functions inherited from decaf::util::Collection< E >
virtual	~Collection ()
Public Member Functions inherited from decaf::lang::Iterable< E >
virtual	~Iterable ()
Public Member Functions inherited from decaf::util::concurrent::Synchronizable
virtual	~Synchronizable ()
Public Member Functions inherited from decaf::util::AbstractCollection< E >
	AbstractCollection ()
virtual	~AbstractCollection ()
AbstractCollection< E > &	operator= (const AbstractCollection< E > &collection)
	Assignment Operator, copy element from the source collection to this collection after clearing any element stored in this collection.
virtual bool	contains (const E &value) const
	Returns true if this collection contains the specified element.More formally, returns true if and only if this collection contains at least one element e such that (value == NULL ? e == NULL : value == e ). Parameters value The value to check for presence in the collection. Returns true if there is at least one of the elements in the collection Exceptions NullPointerException if the Collection contains pointers and the Collection does not allow for NULL elements (optional check).
virtual void	copy (const Collection< E > &collection)
	Renders this Collection as a Copy of the given Collection.
virtual bool	add (const E &value DECAF_UNUSED)
virtual bool	remove (const E &value)
	Removes a single instance of the specified element from the collection.More formally, removes an element e such that (value == NULL ? e == NULL : value == e), if this collection contains one or more such elements. Returns true if this collection contained the specified element (or equivalently, if this collection changed as a result of the call). Parameters value The reference to the element to remove from this Collection. Returns true if the collection was changed, false otherwise. Exceptions UnsupportedOperationExceptio if this is an unmodifiable collection. NullPointerException if the Collection is a container of pointers and does not allow NULL values.
virtual bool	removeAll (const Collection< E > &collection)
	Removes all 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 collection The Collection whose elements are to be removed from this one. Returns true if the collection changed as a result of this call. Exceptions UnsupportedOperationExceptio if this is an unmodifiable collection. NullPointerException if the Collection is a container of pointers and does not allow NULL values.
virtual bool	retainAll (const Collection< E > &collection)
	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 collection The Collection whose elements are to be retained. Returns true if the collection changed as a result of this call. Exceptions UnsupportedOperationExceptio if this is an unmodifiable collection. NullPointerException if the Collection is a container of pointers and does not allow NULL values.
virtual void	lock ()
	Locks the object.
virtual bool	tryLock ()
	Attempts to Lock the object, if the lock is already held by another thread than this method returns false.
virtual void	unlock ()
	Unlocks the object.
virtual void	wait ()
	Waits on a signal from this object, which is generated by a call to Notify.
virtual void	wait (long long millisecs)
	Waits on a signal from this object, which is generated by a call to Notify.
virtual void	wait (long long millisecs, int nanos)
	Waits on a signal from this object, which is generated by a call to Notify.
virtual void	notify ()
	Signals a waiter on this object that it can now wake up and continue.
virtual void	notifyAll ()
	Signals the waiters on this object that it can now wake up and continue.

Additional Inherited Members
Protected Attributes inherited from decaf::util::AbstractCollection< E >
util::concurrent::Mutex	mutex

Detailed Description

template<typename E>
class decaf::util::concurrent::SynchronousQueue< E >

A blocking queue in which each insert operation must wait for a corresponding remove operation by another thread, and vice versa.

A synchronous queue does not have any internal capacity, not even a capacity of one. You cannot peek at a synchronous queue because an element is only present when you try to remove it; you cannot insert an element (using any method) unless another thread is trying to remove it; you cannot iterate as there is nothing to iterate. The head of the queue is the element that the first queued inserting thread is trying to add to the queue; if there is no such queued thread then no element is available for removal and poll() will return null. For purposes of other Collection methods (for example contains), a SynchronousQueue acts as an empty collection. This queue does not permit null elements.

Synchronous queues are similar to rendezvous channels used in CSP and Ada. They are well suited for handoff designs, in which an object running in one thread must sync up with an object running in another thread in order to hand it some information, event, or task.

This class supports an optional fairness policy for ordering waiting producer and consumer threads. By default, this ordering is not guaranteed. However, a queue constructed with fairness set to true grants threads access in FIFO order.

This class and its iterator implement all of the optional methods of the Collection and Iterator interfaces.

Since

1.0

Constructor & Destructor Documentation

template<typename E >

decaf::util::concurrent::SynchronousQueue< E >::SynchronousQueue ( )

inline

template<typename E >

virtual decaf::util::concurrent::SynchronousQueue< E >::~SynchronousQueue ( )

inlinevirtual

Member Function Documentation

template<typename E >

virtual void decaf::util::concurrent::SynchronousQueue< E >::clear ( )

inlinevirtual

Removes all of the elements from this collection (optional operation).The collection will be empty after this method returns.This implementation iterates over this collection, removing each element using the Iterator.remove operation. Most implementations will probably choose to override this method for efficiency.Note that this implementation will throw an UnsupportedOperationException if the iterator returned by this collection's iterator method does not implement the remove method and this collection is non-empty.

Exceptions

UnsupportedOperationException

if the clear operation is not supported by this collection

This implementation repeatedly invokes poll until it returns false.

This implementation repeatedly invokes poll until it returns false.

Reimplemented from decaf::util::AbstractQueue< E >.

template<typename E >

virtual bool decaf::util::concurrent::SynchronousQueue< E >::contains ( const E &value  DECAF_UNUSED ) const

inlinevirtual

template<typename E >

virtual bool decaf::util::concurrent::SynchronousQueue< E >::containsAll ( const Collection< E > &  collection ) const

inlinevirtual

Returns true if this collection contains all of the elements in the specified collection.

Parameters

collection

The Collection to compare to this one.

Exceptions

NullPointerException

if the Collection contains pointers and the Collection does not allow for NULL elements (optional check).

This implementation iterates over the specified collection, checking each element returned by the iterator in turn to see if it's contained in this collection. If all elements are so contained true is returned, otherwise false.

This implementation iterates over the specified collection, checking each element returned by the iterator in turn to see if it's contained in this collection. If all elements are so contained true is returned, otherwise false.

Reimplemented from decaf::util::AbstractCollection< E >.

References decaf::util::Collection< E >::isEmpty().

template<typename E >

virtual int decaf::util::concurrent::SynchronousQueue< E >::drainTo ( Collection< E > &  c )

inlinevirtual

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	the collection to transfer elements into

Returns

the number of elements transferred

Exceptions

UnsupportedOperationException	if addition of elements is not supported by the specified collection
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

Implements decaf::util::concurrent::BlockingQueue< E >.

References decaf::util::Collection< E >::add(), decaf::util::AbstractQueue< E >::element(), and decaf::util::concurrent::SynchronousQueue< E >::poll().

template<typename E >

virtual int decaf::util::concurrent::SynchronousQueue< E >::drainTo ( Collection< E > &  c, int  maxElements  )

inlinevirtual

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	the collection to transfer elements into
maxElements	the maximum number of elements to transfer

Returns

the number of elements transferred

Exceptions

UnsupportedOperationException	if addition of elements is not supported by the specified collection
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

Implements decaf::util::concurrent::BlockingQueue< E >.

References decaf::util::Collection< E >::add(), decaf::util::AbstractQueue< E >::element(), and decaf::util::concurrent::SynchronousQueue< E >::poll().

template<typename E >

virtual bool decaf::util::concurrent::SynchronousQueue< E >::equals ( const Collection< E > &  collection ) const

inlinevirtual

Answers true if this Collection and the one given are the same size and if each element contained in the Collection given is equal to an element contained in this collection.

Parameters

collection

- The Collection to be compared to this one.

Returns

true if this Collection is equal to the one given.

Reimplemented from decaf::util::AbstractCollection< E >.

template<typename E >

virtual bool decaf::util::concurrent::SynchronousQueue< E >::isEmpty ( ) const

inlinevirtual

Returns true if this collection contains no elements.

This implementation returns size() == 0.

Returns

true if the size method return 0.

Reimplemented from decaf::util::AbstractCollection< E >.

template<typename E >

virtual decaf::util::Iterator<E>* decaf::util::concurrent::SynchronousQueue< E >::iterator ( )

inlinevirtual

Returns

an iterator over a set of elements of type T.

Implements decaf::lang::Iterable< E >.

template<typename E >

virtual decaf::util::Iterator<E>* decaf::util::concurrent::SynchronousQueue< E >::iterator ( ) const

inlinevirtual

Implements decaf::lang::Iterable< E >.

template<typename E >

virtual bool decaf::util::concurrent::SynchronousQueue< E >::offer ( const E &  e, long long  timeout, const TimeUnit &  unit  )

inlinevirtual

Inserts the specified element into this queue, waiting if necessary up to the specified wait time for another thread to receive it.

Returns

true if successful, or false if the specified waiting time elapses before a consumer appears.

Exceptions

InterruptedException	Inserts the specified element into this queue, waiting up to the specified wait time if necessary for space to become available.
NullPointerException	Inserts the specified element into this queue, waiting up to the specified wait time if necessary for space to become available.
IllegalArgumentException	Inserts the specified element into this queue, waiting up to the specified wait time if necessary for space to become available.

Implements decaf::util::concurrent::BlockingQueue< E >.

template<typename E >

virtual bool decaf::util::concurrent::SynchronousQueue< E >::offer ( const E &  value )

inlinevirtual

Inserts the specified element into this queue, if another thread is waiting to receive it.

Parameters

value

the element to add to the Queue

Returns

true if the element was added to this queue, else false

Exceptions

NullPointerException	if the Queue implementation does not allow Null values to be inserted into the Queue.
IllegalArgumentException	if some property of the specified element prevents it from being added to this queue

Implements decaf::util::Queue< E >.

template<typename E >

virtual bool decaf::util::concurrent::SynchronousQueue< E >::peek ( E &result  DECAF_UNUSED ) const

inlinevirtual

template<typename E >

virtual bool decaf::util::concurrent::SynchronousQueue< E >::poll ( E &  result, long long  timeout, const TimeUnit &  unit  )

inlinevirtual

Retrieves and removes the head of this queue, waiting if necessary up to the specified wait time, for another thread to insert it.

Parameters

result	a reference to the value where the head of the Queue should be copied to.
timeout	the time that the method should block if there is no element available to return.
unit	the Time Units that the timeout value represents.

Returns

true if the head of the Queue was copied to the result param or false if no value could be returned.

Implements decaf::util::concurrent::BlockingQueue< E >.

Referenced by decaf::util::concurrent::SynchronousQueue< E >::drainTo().

template<typename E >

virtual bool decaf::util::concurrent::SynchronousQueue< E >::poll ( E &  result )

inlinevirtual

Retrieves and removes the head of this queue, if another thread is currently making an element available.

Parameters

result

a reference to the value where the head of the Queue should be copied to.

Returns

true if the head of the Queue was copied to the result param or false if no value could be returned.

Implements decaf::util::Queue< E >.

template<typename E >

virtual void decaf::util::concurrent::SynchronousQueue< E >::put ( const E &  value )

inlinevirtual

Adds the specified element to this queue, waiting if necessary for another thread to receive it.

Parameters

value

the element to add to the Queue.

Exceptions

InterruptedException	Inserts the specified element into this queue, waiting if necessary for space to become available.
NullPointerException	Inserts the specified element into this queue, waiting if necessary for space to become available.
IllegalArgumentException	Inserts the specified element into this queue, waiting if necessary for space to become available.

Implements decaf::util::concurrent::BlockingQueue< E >.

template<typename E >

virtual int decaf::util::concurrent::SynchronousQueue< E >::remainingCapacity ( ) const

inlinevirtual

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.

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

the remaining capacity

Implements decaf::util::concurrent::BlockingQueue< E >.

template<typename E >

virtual bool decaf::util::concurrent::SynchronousQueue< E >::remove ( const E &value  DECAF_UNUSED )

inlinevirtual

template<typename E >

virtual bool decaf::util::concurrent::SynchronousQueue< E >::removeAll ( const Collection< E > &collection  DECAF_UNUSED )

inlinevirtual

template<typename E >

virtual bool decaf::util::concurrent::SynchronousQueue< E >::retainAll ( const Collection< E > &collection  DECAF_UNUSED )

inlinevirtual

template<typename E >

virtual int decaf::util::concurrent::SynchronousQueue< E >::size ( ) const

inlinevirtual

Returns the number of elements in this collection.

If this collection contains more than Integer::MAX_VALUE elements, returns Integer::MAX_VALUE.

Returns

the number of elements in this collection

Implements decaf::util::Collection< E >.

template<typename E >

virtual E decaf::util::concurrent::SynchronousQueue< E >::take ( )

inlinevirtual

Retrieves and removes the head of this queue, waiting if necessary for another thread to insert it.

Returns

the head of this queue

Exceptions

InterruptedException

Retrieves and removes the head of this queue, waiting if necessary until an element becomes available.

Implements decaf::util::concurrent::BlockingQueue< E >.

template<typename E >

virtual std::vector<E> decaf::util::concurrent::SynchronousQueue< E >::toArray ( ) const

inlinevirtual

Answers an STL vector containing copies of all elements contained in this Collection.

All the elements in the array will not be referenced by the collection. The elements in the returned array will be sorted to the same order as those returned by the iterator of this collection itself if the collection guarantees the order.

Returns

an vector of copies of all the elements from this Collection

Reimplemented from decaf::util::AbstractCollection< E >.

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The documentation for this class was generated from the following file:

• src/main/decaf/util/concurrent/SynchronousQueue.h