seda.sandStorm.core
Class FiniteQueue

java.lang.Object
  seda.sandStorm.core.FiniteQueue

All Implemented Interfaces:

ProfilableIF, QueueIF, SinkIF, SourceIF

Direct Known Subclasses:

EventSink

public class FiniteQueue
extends java.lang.Object
implements QueueIF, ProfilableIF

The FiniteQueue class is a simple implementation of the QueueIF interface, using a linked list.

See Also:

QueueIF

Field Summary

private java.lang.Object	blocker
private static boolean	DEBUG
private java.lang.String	name
private EnqueuePredicateIF	pred
private java.util.Hashtable<java.lang.Object,QueueElementIF[]>	provisionalTbl
private ssLinkedList	qlist
private int	queueSize

Constructor Summary

FiniteQueue()
Create a FiniteQueue with no enqueue predicate.

FiniteQueue(EnqueuePredicateIF pred)
Create a FiniteQueue with the given enqueue predicate.

FiniteQueue(java.lang.String name)
Create a FiniteQueue with no enqueue and the given name.

Method Summary

QueueElementIF[]	blocking_dequeue_all(int timeout_millis) This method blocks on the queue up until a timeout occurs or until an element appears on the queue.
QueueElementIF	blocking_dequeue(int timeout_millis) Just like blocking_dequeue_all, but returns only a single element.
QueueElementIF[]	blocking_dequeue(int timeout_millis, int num) This method blocks on the queue up until a timeout occurs or until an element appears on the queue.
QueueElementIF[]	blocking_dequeue(int timeout_millis, int num, boolean mustReturnNum)
QueueElementIF[]	dequeue_all() Dequeues all available elements, or returns null if there is nothing left on the queue.
QueueElementIF	dequeue() Dequeues the next element, or returns null if there is nothing left on the queue.
QueueElementIF[]	dequeue(int num) Dequeues at most num available elements, or returns null if there is nothing left on the queue.
QueueElementIF[]	dequeue(int num, boolean mustReturnNum)
void	enqueue_abort(java.lang.Object key) Abort a provisional enqueue.
void	enqueue_commit(java.lang.Object key) Commit a provisional enqueue.
boolean	enqueue_lossy(QueueElementIF enqueueMe) Enqueues the given element onto the queue.
void	enqueue_many(QueueElementIF[] enqueueMe) Given an array of elements, atomically enqueues all of the elements in the array.
java.lang.Object	enqueue_prepare(QueueElementIF[] enqueueMe) Provisionally enqueue the given elements.
void	enqueue(QueueElementIF enqueueMe) Enqueues the given element onto the queue.
EnqueuePredicateIF	getEnqueuePredicate() Return the enqueue predicate for this sink.
protected java.lang.String	getName() Returns the name of the FiniteQueue, setting it if null.
private void	initName()
int	profileSize() Return the profile size of the queue.
void	setEnqueuePredicate(EnqueuePredicateIF pred) Set the enqueue predicate for this sink.
int	size() Return the size of the queue.
java.lang.String	toString()

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Field Detail

DEBUG

private static final boolean DEBUG

See Also:

Constant Field Values

qlist

private ssLinkedList qlist

queueSize

private int queueSize

blocker

private java.lang.Object blocker

provisionalTbl

private java.util.Hashtable<java.lang.Object,QueueElementIF[]> provisionalTbl

pred

private EnqueuePredicateIF pred

name

private java.lang.String name

Constructor Detail

FiniteQueue

public FiniteQueue(EnqueuePredicateIF pred)

Create a FiniteQueue with the given enqueue predicate.

FiniteQueue

public FiniteQueue()

Create a FiniteQueue with no enqueue predicate.

FiniteQueue

public FiniteQueue(java.lang.String name)

Create a FiniteQueue with no enqueue and the given name. Used for debugging.

Method Detail

size

public int size()

Return the size of the queue.

Specified by:

size in interface SinkIF

Specified by:

size in interface SourceIF

enqueue

public void enqueue(QueueElementIF enqueueMe)
             throws SinkFullException

Description copied from interface: SinkIF

Enqueues the given element onto the queue.

Specified by:

enqueue in interface SinkIF

Parameters:

enqueueMe - The QueueElementIF to enqueue

Throws:

SinkFullException - Indicates that the sink is temporarily full.

enqueue_lossy

public boolean enqueue_lossy(QueueElementIF enqueueMe)

Description copied from interface: SinkIF

Enqueues the given element onto the queue. This is lossy in that this method drops the element if the element could not be enqueued, rather than throwing a SinkFullException or SinkClosedException. This is meant as a convenience interface for "low priority" enqueue events which can be safely dropped.

Specified by:

enqueue_lossy in interface SinkIF

Parameters:

enqueueMe - The QueueElementIF to enqueue

Returns:

true if the element was enqueued, false otherwise.

enqueue_many

public void enqueue_many(QueueElementIF[] enqueueMe)
                  throws SinkFullException

Description copied from interface: SinkIF

Given an array of elements, atomically enqueues all of the elements in the array. This guarantees that no other thread can interleave its own elements with those being inserted from this array. The implementation must enqueue all of the elements or none of them; if a SinkFullException or SinkClosedException is thrown, none of the elements will have been enqueued. This implies that the enqueue predicate (if any) must accept all elements in the array for the enqueue to proceed.

Specified by:

enqueue_many in interface SinkIF

Parameters:

enqueueMe - The element array to enqueue

Throws:

SinkFullException - Indicates that the sink is temporarily full.

dequeue

public QueueElementIF dequeue()

Description copied from interface: SourceIF

Dequeues the next element, or returns null if there is nothing left on the queue.

Specified by:

dequeue in interface SourceIF

Returns:

the next QueueElementIF on the queue

dequeue_all

public QueueElementIF[] dequeue_all()

Description copied from interface: SourceIF

Dequeues all available elements, or returns null if there is nothing left on the queue.

Specified by:

dequeue_all in interface SourceIF

Returns:

all pending QueueElementIFs on the queue

dequeue

public QueueElementIF[] dequeue(int num)

Description copied from interface: SourceIF

Dequeues at most num available elements, or returns null if there is nothing left on the queue.

Specified by:

dequeue in interface SourceIF

Returns:

At most num QueueElementIFs on the queue

dequeue

public QueueElementIF[] dequeue(int num,
                                boolean mustReturnNum)

blocking_dequeue_all

public QueueElementIF[] blocking_dequeue_all(int timeout_millis)

Description copied from interface: SourceIF

This method blocks on the queue up until a timeout occurs or until an element appears on the queue. It returns all elements waiting on the queue at that time.

Specified by:

blocking_dequeue_all in interface SourceIF

Parameters:

timeout_millis - if timeout_millis is 0, this method will be non-blocking and will return right away, whether or not any elements are pending on the queue. If timeout_millis is -1, this method blocks forever until something is available. If timeout_millis is positive, this method will wait about that number of milliseconds before returning, but possibly a little more.

Returns:

an array of QueueElementIF's. This array will be null if no elements were pending.

blocking_dequeue

public QueueElementIF[] blocking_dequeue(int timeout_millis,
                                         int num,
                                         boolean mustReturnNum)

blocking_dequeue

public QueueElementIF[] blocking_dequeue(int timeout_millis,
                                         int num)

Description copied from interface: SourceIF

This method blocks on the queue up until a timeout occurs or until an element appears on the queue. It returns at most num elements waiting on the queue at that time.

Specified by:

blocking_dequeue in interface SourceIF

blocking_dequeue

public QueueElementIF blocking_dequeue(int timeout_millis)

Description copied from interface: SourceIF

Just like blocking_dequeue_all, but returns only a single element.

Specified by:

blocking_dequeue in interface SourceIF

profileSize

public int profileSize()

Return the profile size of the queue.

Specified by:

profileSize in interface ProfilableIF

enqueue_prepare

public java.lang.Object enqueue_prepare(QueueElementIF[] enqueueMe)
                                 throws SinkException

Provisionally enqueue the given elements.

Specified by:

enqueue_prepare in interface SinkIF

Parameters:

enqueueMe - The element array to provisionally enqueue

Returns:

A "transaction key" that may be used to commit or abort the provisional enqueue

Throws:

SinkFullException - Indicates that the sink is temporarily full and that the requested elements could not be provisionally enqueued.

SinkClosedException - Indicates that the sink is no longer being serviced.

SinkException

See Also:

enqueue_commit, enqueue_abort

enqueue_commit

public void enqueue_commit(java.lang.Object key)

Commit a provisional enqueue.

Specified by:

enqueue_commit in interface SinkIF

enqueue_abort

public void enqueue_abort(java.lang.Object key)

Abort a provisional enqueue.

Specified by:

enqueue_abort in interface SinkIF

setEnqueuePredicate

public void setEnqueuePredicate(EnqueuePredicateIF pred)

Set the enqueue predicate for this sink.

Specified by:

setEnqueuePredicate in interface SinkIF

getEnqueuePredicate

public EnqueuePredicateIF getEnqueuePredicate()

Return the enqueue predicate for this sink.

Specified by:

getEnqueuePredicate in interface SinkIF

initName

private void initName()

getName

protected java.lang.String getName()

Returns the name of the FiniteQueue, setting it if null. Uses test and test-and-set to avoid the lock overhead in most cases.

toString

public java.lang.String toString()

Overrides:

toString in class java.lang.Object