alma.acs.nc

Class CircularQueue<T>

java.lang.Object

alma.acs.nc.CircularQueue<T>

public class CircularQueue<T>
extends java.lang.Object

Circular Queue that can buffer events while the Notify Service is down.

Currently we store the event data twice: Both the StructuredEvent with Corba Anys inside (incl. the user data), and also the user data separately. This design relieves us from transforming the user data back from Corba Any to IDL-generated struct. If this becomes a memory issue, we may have to change it.

Author:

Jorge Avarias

See Also:

NCPublisher#publishCORBAEvent(StructuredEvent, T)

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
class	CircularQueue.Data

Constructor Summary

Constructors

Constructor and Description
CircularQueue() Initializes the Queue with default value = 100
CircularQueue(int size) Initializes the Queue with custom value size

Method Summary

Modifier and Type	Method and Description
void	clear() Remove all the elements of the queue
int	getMaxSize()
CircularQueue.Data	pop() Remove the first element in the queue and return it.
CircularQueue.Data	push(StructuredEvent e, T userData) Insert a structured event at the end of the queue.
boolean	setMaxSize(int size) Set the capacity of the queue.

Methods inherited from class java.lang.Object

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

Constructor Detail

CircularQueue

public CircularQueue(int size)

Initializes the Queue with custom value size

Parameters:

size - the size of the queue

CircularQueue

public CircularQueue()

Initializes the Queue with default value = 100

Method Detail

push

public CircularQueue.Data push(StructuredEvent e,
                               T userData)

Insert a structured event at the end of the queue. If the queue is full, inserts the structured event and remove the first event in the queue

Parameters:

e - the event to be inserted in the queue

Returns:

null if all went well, or otherwise the data for another event that had to be pushed out of the queue if the queue was full.

clear

public void clear()

Remove all the elements of the queue

pop

public CircularQueue.Data pop()

Remove the first element in the queue and return it. If there is no elements in the queue returns null

Returns:

the first element in the queue

setMaxSize

public boolean setMaxSize(int size)

Set the capacity of the queue. It only changes the capacity when the given size is greater than the current one.

Returns:

true when the capacity of the queue has been changed. Otherwise returns false.

getMaxSize

public int getMaxSize()

Returns:

the current capacity of the queue