org.apache.zookeeper.server

Class ExpiryQueue<E>

java.lang.Object

org.apache.zookeeper.server.ExpiryQueue<E>

public class ExpiryQueue<E>
extends Object

ExpiryQueue tracks elements in time sorted fixed duration buckets. It's used by SessionTrackerImpl to expire sessions and NIOServerCnxnFactory to expire connections.

Constructor Summary

Constructors

Constructor and Description
ExpiryQueue(int expirationInterval)

Method Summary

Modifier and Type	Method and Description
void	dump(PrintWriter pwriter)
Map<Long,Set<E>>	getExpiryMap() Returns an unmodifiable view of the expiration time -> elements mapping.
long	getWaitTime()
Set<E>	poll() Remove the next expired set of elements from expireMap.
Long	remove(E elem) Removes element from the queue.
Long	update(E elem, int timeout) Adds or updates expiration time for element in queue, rounding the timeout to the expiry interval bucketed used by this queue.

Methods inherited from class java.lang.Object

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

Constructor Detail

ExpiryQueue

public ExpiryQueue(int expirationInterval)

Method Detail

remove

public Long remove(E elem)

Removes element from the queue.

Parameters:

elem - element to remove

Returns:

time at which the element was set to expire, or null if it wasn't present

update

public Long update(E elem,
                   int timeout)

Adds or updates expiration time for element in queue, rounding the timeout to the expiry interval bucketed used by this queue.

Parameters:

elem - element to add/update

timeout - timout in milliseconds

Returns:

time at which the element is now set to expire if changed, or null if unchanged

getWaitTime

public long getWaitTime()

Returns:

milliseconds until next expiration time, or 0 if has already past

poll

public Set<E> poll()

Remove the next expired set of elements from expireMap. This method needs to be called frequently enough by checking getWaitTime(), otherwise there will be a backlog of empty sets queued up in expiryMap.

Returns:

next set of expired elements, or an empty set if none are ready

dump

public void dump(PrintWriter pwriter)

getExpiryMap

public Map<Long,Set<E>> getExpiryMap()

Returns an unmodifiable view of the expiration time -> elements mapping.