Class ForwardingBlockingQueue<E>
- java.lang.Object
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- com.google.common.collect.ForwardingObject
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- com.google.common.collect.ForwardingCollection<E>
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- com.google.common.collect.ForwardingQueue<E>
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- com.google.common.util.concurrent.ForwardingBlockingQueue<E>
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- Type Parameters:
E
- the type of elements held in this collection
- All Implemented Interfaces:
Iterable<E>
,Collection<E>
,BlockingQueue<E>
,Queue<E>
@CanIgnoreReturnValue @GwtIncompatible public abstract class ForwardingBlockingQueue<E> extends ForwardingQueue<E> implements BlockingQueue<E>
ABlockingQueue
which forwards all its method calls to anotherBlockingQueue
. Subclasses should override one or more methods to modify the behavior of the backing collection as desired per the decorator pattern.default
method warning: This class does not forward calls todefault
methods. Instead, it inherits their default implementations. When those implementations invoke methods, they invoke methods on theForwardingBlockingQueue
.- Since:
- 4.0
- Author:
- Raimundo Mirisola
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Constructor Summary
Constructors Modifier Constructor Description protected
ForwardingBlockingQueue()
Constructor for use by subclasses.
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Method Summary
All Methods Instance Methods Abstract Methods Concrete Methods Modifier and Type Method Description protected abstract BlockingQueue<E>
delegate()
Returns the backing delegate instance that methods are forwarded to.int
drainTo(Collection<? super E> c)
Removes all available elements from this queue and adds them to the given collection.int
drainTo(Collection<? super E> c, int maxElements)
Removes at most the given number of available elements from this queue and adds them to the given collection.boolean
offer(E e, long timeout, TimeUnit unit)
Inserts the specified element into this queue, waiting up to the specified wait time if necessary for space to become available.E
poll(long timeout, 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.void
put(E e)
Inserts the specified element into this queue, waiting if necessary for space to become available.int
remainingCapacity()
Returns the number of additional elements that this queue can ideally (in the absence of memory or resource constraints) accept without blocking, orInteger.MAX_VALUE
if there is no intrinsic limit.E
take()
Retrieves and removes the head of this queue, waiting if necessary until an element becomes available.-
Methods inherited from class com.google.common.collect.ForwardingQueue
element, offer, peek, poll, remove, standardOffer, standardPeek, standardPoll
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Methods inherited from class com.google.common.collect.ForwardingCollection
add, addAll, clear, contains, containsAll, isEmpty, iterator, remove, removeAll, retainAll, size, standardAddAll, standardClear, standardContains, standardContainsAll, standardIsEmpty, standardRemove, standardRemoveAll, standardRetainAll, standardToArray, standardToArray, standardToString, toArray, toArray
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Methods inherited from class com.google.common.collect.ForwardingObject
toString
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Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait
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Methods inherited from interface java.util.concurrent.BlockingQueue
add, contains, offer, remove
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Methods inherited from interface java.util.Collection
addAll, clear, containsAll, equals, hashCode, isEmpty, iterator, parallelStream, removeAll, removeIf, retainAll, size, spliterator, stream, toArray, toArray, toArray
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Constructor Detail
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ForwardingBlockingQueue
protected ForwardingBlockingQueue()
Constructor for use by subclasses.
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Method Detail
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delegate
protected abstract BlockingQueue<E> delegate()
Description copied from class:ForwardingObject
Returns the backing delegate instance that methods are forwarded to. Abstract subclasses generally override this method with an abstract method that has a more specific return type, such asForwardingSet.delegate()
. Concrete subclasses override this method to supply the instance being decorated.- Specified by:
delegate
in classForwardingQueue<E>
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drainTo
public int drainTo(Collection<? super E> c, int maxElements)
Description copied from interface:java.util.concurrent.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 collectionc
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 inIllegalArgumentException
. Further, the behavior of this operation is undefined if the specified collection is modified while the operation is in progress.- Specified by:
drainTo
in interfaceBlockingQueue<E>
- Parameters:
c
- the collection to transfer elements intomaxElements
- the maximum number of elements to transfer- Returns:
- the number of elements transferred
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drainTo
public int drainTo(Collection<? super E> c)
Description copied from interface:java.util.concurrent.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 collectionc
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 inIllegalArgumentException
. Further, the behavior of this operation is undefined if the specified collection is modified while the operation is in progress.- Specified by:
drainTo
in interfaceBlockingQueue<E>
- Parameters:
c
- the collection to transfer elements into- Returns:
- the number of elements transferred
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offer
public boolean offer(E e, long timeout, TimeUnit unit) throws InterruptedException
Description copied from interface:java.util.concurrent.BlockingQueue
Inserts the specified element into this queue, waiting up to the specified wait time if necessary for space to become available.- Specified by:
offer
in interfaceBlockingQueue<E>
- Parameters:
e
- the element to addtimeout
- how long to wait before giving up, in units ofunit
unit
- aTimeUnit
determining how to interpret thetimeout
parameter- Returns:
true
if successful, orfalse
if the specified waiting time elapses before space is available- Throws:
InterruptedException
- if interrupted while waiting
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poll
@CheckForNull public E poll(long timeout, TimeUnit unit) throws InterruptedException
Description copied from interface:java.util.concurrent.BlockingQueue
Retrieves and removes the head of this queue, waiting up to the specified wait time if necessary for an element to become available.- Specified by:
poll
in interfaceBlockingQueue<E>
- Parameters:
timeout
- how long to wait before giving up, in units ofunit
unit
- aTimeUnit
determining how to interpret thetimeout
parameter- Returns:
- the head of this queue, or
null
if the specified waiting time elapses before an element is available - Throws:
InterruptedException
- if interrupted while waiting
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put
public void put(E e) throws InterruptedException
Description copied from interface:java.util.concurrent.BlockingQueue
Inserts the specified element into this queue, waiting if necessary for space to become available.- Specified by:
put
in interfaceBlockingQueue<E>
- Parameters:
e
- the element to add- Throws:
InterruptedException
- if interrupted while waiting
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remainingCapacity
public int remainingCapacity()
Description copied from interface:java.util.concurrent.BlockingQueue
Returns the number of additional elements that this queue can ideally (in the absence of memory or resource constraints) accept without blocking, orInteger.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.- Specified by:
remainingCapacity
in interfaceBlockingQueue<E>
- Returns:
- the remaining capacity
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take
public E take() throws InterruptedException
Description copied from interface:java.util.concurrent.BlockingQueue
Retrieves and removes the head of this queue, waiting if necessary until an element becomes available.- Specified by:
take
in interfaceBlockingQueue<E>
- Returns:
- the head of this queue
- Throws:
InterruptedException
- if interrupted while waiting
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