Java in a Nutshell, 5th Edition [Electronic resources] نسخه متنی

This
interface extends the
java.util.Queue interface of the Java Collections
Framework and adds blocking put( ) and
take( ) methods. Blocking queues are useful in
many concurrent algorithms in which a producer thread puts objects
onto a queue and a consumer thread removes them for some kind of
processing. The producer thread must block if a bounded queue fills
up, and the consumer thread must block if no objects are available on
the queue.

In addition to put( ) and take(
) methods that block indefinitely,
BlockingQueue also defines timed versions of the
Queue methods offer( ) and
poll( ) that wait up to the specified time. The
timeout is specified as both a long and a
TimeUnit constant.

drainTo( ) removes all available elements from a
BlockingQueue, adds them to the specified
collection, and returns the number of elements removed from the
queue. drainTo( ) does not block. A variant on
this method puts an upper bound on the number of elements removed
from the queue.

remainingCapacity( ) returns the number of
elements that can be added to the queue before it becomes full or
returns Integer.MAX_VALUE if the
BlockingQueue is not a bounded queue. For bounded
queues, this method provides a hint as to whether a call to
put( ) will block.

BlockingQueue implementations are not allowed to
accept null elements. The
BlockingQueue interface refines the
Collection.add( ) and Queue.offer(
) contracts to indicate that these methods throw
NullPointerException if passed a
null value.

Figure 16-72. java.util.concurrent.BlockingQueue<E>

public interface

BlockingQueue<E> extends java.util.Queue<E> {
// Public Instance Methods
boolean

add (E

o );
int

drainTo (java.util.Collection<? super E>

c );
int

drainTo (java.util.Collection<? super E>

c , int

maxElements );
boolean

offer (E

o );
boolean

offer (E

o , long

timeout , TimeUnit

unit ) throws InterruptedException;
E

poll (long

timeout , TimeUnit

unit ) throws InterruptedException;
void

put (E

o ) throws InterruptedException;
int

remainingCapacity ( );
E

take ( ) throws InterruptedException;
}

Implementations

ArrayBlockingQueue, DelayQueue,
LinkedBlockingQueue,
PriorityBlockingQueue,
SynchronousQueue

Passed To

ExecutorCompletionService.ExecutorCompletionService(
), ThreadPoolExecutor.ThreadPoolExecutor(
)

Returned By

ScheduledThreadPoolExecutor.getQueue( ),
ThreadPoolExecutor.getQueue( )