org.pvalsecc.concurrent

Class FArrayBlockingQueue<E>

java.lang.Object

java.util.AbstractCollection<E>

java.util.AbstractQueue<E>

org.pvalsecc.concurrent.FArrayBlockingQueue<E>

All Implemented Interfaces:

java.lang.Iterable<E>, java.util.Collection<E>, java.util.concurrent.BlockingQueue<E>, java.util.Queue<E>

public final class FArrayBlockingQueue<E>
extends java.util.AbstractQueue<E>
implements java.util.concurrent.BlockingQueue<E>

Very much similar to the JDK ArrayBlockingQueue class.

When the producer threads are blocked due to a queue full event, then the consumer threads will not signal the producers until a lower mark is reached again. The point is to give maximum CPU resources to the consumer threads for a while.

Constructor Summary

Constructors

Constructor and Description
FArrayBlockingQueue(int capacity) Creates an ArrayBlockingQueue with the given (fixed) capacity and default access policy.

Method Summary

Methods

Modifier and Type	Method and Description
int	blockingDrainTo(java.util.Collection<? super E> c, int maxElements) Same as drainTo, but blocks until at least one element is available.
void	clear() Atomically removes all of the elements from this queue.
boolean	contains(java.lang.Object o)
int	drainTo(java.util.Collection<? super E> c)
int	drainTo(java.util.Collection<? super E> c, int maxElements)
java.util.Iterator<E>	iterator() Returns an iterator over the elements in this queue in proper sequence.
boolean	offer(E o) Inserts the specified element at the tail of this queue if possible, returning immediately if this queue is full.
boolean	offer(E o, long timeout, java.util.concurrent.TimeUnit unit) Inserts the specified element at the tail of this queue, waiting if necessary up to the specified wait time for space to become available.
E	peek()
E	poll()
E	poll(long timeout, java.util.concurrent.TimeUnit unit)
void	put(E o) Adds the specified element to the tail of this queue, waiting if necessary for space to become available.
void	put(java.util.List<E> objects) Like put(Object), but for multiple entries.
int	remainingCapacity() Returns the number of elements that this queue can ideally (in the absence of memory or resource constraints) accept without blocking.
boolean	remove(java.lang.Object o) Removes a single instance of the specified element from this queue, if it is present.
int	size()
E	take()
java.lang.Object[]	toArray()
<T> T[]	toArray(T[] a)
java.lang.String	toString()

Methods inherited from class java.util.AbstractQueue

add, addAll, element, remove

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.concurrent.BlockingQueue

add

Methods inherited from interface java.util.Queue

element, remove

Methods inherited from interface java.util.Collection

addAll, containsAll, equals, hashCode, isEmpty, removeAll, retainAll

Constructor Detail

FArrayBlockingQueue

public FArrayBlockingQueue(int capacity)

Creates an ArrayBlockingQueue with the given (fixed) capacity and default access policy.

Parameters:

capacity - the capacity of this queue

Throws:

java.lang.IllegalArgumentException - if capacity is less than 1

Method Detail

offer

public boolean offer(E o)

Inserts the specified element at the tail of this queue if possible, returning immediately if this queue is full.

Specified by:

offer in interface java.util.concurrent.BlockingQueue<E>

Specified by:

offer in interface java.util.Queue<E>

Parameters:

o - the element to add.

Returns:

true if it was possible to add the element to this queue, else false

Throws:

java.lang.NullPointerException - if the specified element is null

offer

public boolean offer(E o,
            long timeout,
            java.util.concurrent.TimeUnit unit)
              throws java.lang.InterruptedException

Inserts the specified element at the tail of this queue, waiting if necessary up to the specified wait time for space to become available.

Specified by:

offer in interface java.util.concurrent.BlockingQueue<E>

Parameters:

o - 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:

java.lang.InterruptedException - if interrupted while waiting.

java.lang.NullPointerException - if the specified element is null.

poll

public E poll()

Specified by:

poll in interface java.util.Queue<E>

poll

public E poll(long timeout,
     java.util.concurrent.TimeUnit unit)
       throws java.lang.InterruptedException

Specified by:

poll in interface java.util.concurrent.BlockingQueue<E>

Throws:

java.lang.InterruptedException

remove

public boolean remove(java.lang.Object o)

Removes a single instance of the specified element from this queue, if it is present.

Specified by:

remove in interface java.util.Collection<E>

Specified by:

remove in interface java.util.concurrent.BlockingQueue<E>

Overrides:

remove in class java.util.AbstractCollection<E>

peek

public E peek()

Specified by:

peek in interface java.util.Queue<E>

take

public E take()
       throws java.lang.InterruptedException

Specified by:

take in interface java.util.concurrent.BlockingQueue<E>

Throws:

java.lang.InterruptedException

put

public void put(E o)
         throws java.lang.InterruptedException

Adds the specified element to the tail of this queue, waiting if necessary for space to become available.

Specified by:

put in interface java.util.concurrent.BlockingQueue<E>

Parameters:

o - the element to add

Throws:

java.lang.InterruptedException - if interrupted while waiting.

java.lang.NullPointerException - if the specified element is null.

put

public void put(java.util.List<E> objects)
         throws java.lang.InterruptedException

Like put(Object), but for multiple entries.

Throws:

java.lang.InterruptedException

size

public int size()

Specified by:

size in interface java.util.Collection<E>

Specified by:

size in class java.util.AbstractCollection<E>

Returns:

an approximative number of elements in this queue.

remainingCapacity

public int remainingCapacity()

Returns the number of elements that this queue can ideally (in the absence of memory or resource constraints) accept without blocking. This is always equal to the initial capacity of this queue less the current size of this queue.

Note that you cannot always tell if an attempt to add an element will succeed by inspecting remainingCapacity because it may be the case that a waiting consumer is ready to take an element out of an otherwise full queue.

Specified by:

remainingCapacity in interface java.util.concurrent.BlockingQueue<E>

contains

public boolean contains(java.lang.Object o)

Specified by:

contains in interface java.util.Collection<E>

Specified by:

contains in interface java.util.concurrent.BlockingQueue<E>

Overrides:

contains in class java.util.AbstractCollection<E>

toArray

public java.lang.Object[] toArray()

Specified by:

toArray in interface java.util.Collection<E>

Overrides:

toArray in class java.util.AbstractCollection<E>

toArray

public <T> T[] toArray(T[] a)

Specified by:

toArray in interface java.util.Collection<E>

Overrides:

toArray in class java.util.AbstractCollection<E>

toString

public java.lang.String toString()

Overrides:

toString in class java.util.AbstractCollection<E>

clear

public void clear()

Atomically removes all of the elements from this queue. The queue will be empty after this call returns.

Specified by:

clear in interface java.util.Collection<E>

Overrides:

clear in class java.util.AbstractQueue<E>

drainTo

public int drainTo(java.util.Collection<? super E> c)

Specified by:

drainTo in interface java.util.concurrent.BlockingQueue<E>

drainTo

public int drainTo(java.util.Collection<? super E> c,
          int maxElements)

Specified by:

drainTo in interface java.util.concurrent.BlockingQueue<E>

blockingDrainTo

public int blockingDrainTo(java.util.Collection<? super E> c,
                  int maxElements)
                    throws java.lang.InterruptedException

Same as drainTo, but blocks until at least one element is available.

Throws:

java.lang.InterruptedException

iterator

public java.util.Iterator<E> iterator()

Returns an iterator over the elements in this queue in proper sequence. The returned Iterator is a "weakly consistent" iterator that will never throw ConcurrentModificationException, and guarantees to traverse elements as they existed upon construction of the iterator, and may (but is not guaranteed to) reflect any modifications subsequent to construction.

Specified by:

iterator in interface java.lang.Iterable<E>

Specified by:

iterator in interface java.util.Collection<E>

Specified by:

iterator in class java.util.AbstractCollection<E>

Returns:

an iterator over the elements in this queue in proper sequence.