org.apache.river.outrigger

Class EventRegistrationWatcher

java.lang.Object

org.apache.river.outrigger.TransitionWatcher

org.apache.river.outrigger.EventRegistrationWatcher

All Implemented Interfaces:

Comparable<TransitionWatcher>, LeasedResource, EventRegistrationRecord

Direct Known Subclasses:

StorableEventWatcher, TransactableEventWatcher

abstract class EventRegistrationWatcher
extends TransitionWatcher
implements EventRegistrationRecord

Subclass of TransitionWatcher for event registrations. Also represents the registration itself.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
private class	EventRegistrationWatcher.BasicEventSender Common implementation of EventSender.

Field Summary

Fields

Modifier and Type	Field and Description
(package private) Uuid	cookie The UUID that identifies this registration Protected, but only for use by subclasses.
private long	currentSeqNum The current sequence number.
(package private) long	eventID The event ID associated with this registration Protected, but only for use by subclasses.
(package private) long	expiration The current expiration time of the registration Protected, but only for use by subclasses.
(package private) MarshalledObject	handback The handback associated with this registration.
private TemplateHandle	owner The TemplateHandle associated with this watcher.

Fields inherited from class org.apache.river.outrigger.TransitionWatcher

startOrdinal

Constructor Summary

Constructors

Constructor and Description
EventRegistrationWatcher(long timestamp, long startOrdinal, long currentSeqNum) Used during log recovery to create a mostly empty EventRegistrationWatcher.
EventRegistrationWatcher(long timestamp, long startOrdinal, Uuid cookie, MarshalledObject handback, long eventID) Create a new EventRegistrationWatcher.

Method Summary

Modifier and Type	Method and Description
(package private) boolean	addTemplateHandle(TemplateHandle h) Associate a TemplateHandle with this object.
boolean	cancel() Make sure this object will be removed from the system independent of the expiration time.
(package private) void	cleanup(TemplateHandle owner, boolean expired) Overridden by subclasses if there is any cleanup work they need to do as part of cancel or removeIfExpired.
private boolean	doRemove(long now, boolean doIt) The heavy lifting of removing ourselves.
Uuid	getCookie() Get the unique identifier associated with this object.
long	getExpiration() Get the expiration time of this object.
(package private) abstract RemoteEventListener	getListener(ProxyPreparer preparer) Return the remote listener associated with this EventRegistrationWatcher.
(package private) void	process(EntryTransition transition, long now) Process the given transition by queuing up a task with the notifier for event delivery.
(package private) void	removeIfExpired(long now) Remove this watcher from the system if it has expired.
void	setExpiration(long newExpiration) Set the expiration time of this object.

Methods inherited from class org.apache.river.outrigger.TransitionWatcher

compareTo, isInterested

Methods inherited from class java.lang.Object

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

Field Detail

expiration

volatile long expiration

The current expiration time of the registration Protected, but only for use by subclasses.

cookie

Uuid cookie

The UUID that identifies this registration Protected, but only for use by subclasses. Should not be changed.

handback

MarshalledObject handback

The handback associated with this registration. Protected, but only for use by subclasses. Should not be changed.

eventID

long eventID

The event ID associated with this registration Protected, but only for use by subclasses. Should not be changed.

currentSeqNum

private long currentSeqNum

The current sequence number.

owner

private TemplateHandle owner

The TemplateHandle associated with this watcher.

Constructor Detail

EventRegistrationWatcher

EventRegistrationWatcher(long timestamp,
                         long startOrdinal,
                         long currentSeqNum)

Used during log recovery to create a mostly empty EventRegistrationWatcher.

Note, we set the time stamp and tie-breaker here instead of getting them from the log. This means they will be inconstant with their value from the last VM we were in, but since they never leak out and events are read-only anyway this should not be a problem (this also allows us to keep the tie-breaker and time stamp in final fields).

Parameters:

timestamp - the value that is used to sort TransitionWatchers.

startOrdinal - the highest ordinal associated with operations that are considered to have occurred before the operation associated with this watcher.

currentSeqNum - Sequence number to start with.

EventRegistrationWatcher

EventRegistrationWatcher(long timestamp,
                         long startOrdinal,
                         Uuid cookie,
                         MarshalledObject handback,
                         long eventID)

Create a new EventRegistrationWatcher.

Parameters:

timestamp - the value that is used to sort TransitionWatchers.

startOrdinal - the highest ordinal associated with operations that are considered to have occurred before the operation associated with this watcher.

cookie - The unique identifier associated with this watcher. Must not be null.

handback - The handback object that should be sent along with event notifications to the the listener.

eventID - The event ID for event type represented by this object.

Throws:

NullPointerException - if the cookie argument is null.

Method Detail

process

void process(EntryTransition transition,
             long now)

Process the given transition by queuing up a task with the notifier for event delivery. Assumes the passed entry matches the template in the TemplateHandle associated with this watcher and that isInterested returned true. If remove has been called or the expiration time of this watcher has passed, this call should have no effect. This call may cause the watcher to be removed.

Specified by:

process in class TransitionWatcher

Parameters:

transition - A EntryTransition that describes the transition and what entry is transitioning. This method will assume that transition.getHandle returns a non-null value.

now - An estimate of the current time (not the time when the event occured).

Throws:

NullPointerException - if transition is null.

getListener

abstract RemoteEventListener getListener(ProxyPreparer preparer)
                                  throws ClassNotFoundException,
                                         IOException

Return the remote listener associated with this EventRegistrationWatcher. Optionally prepare the listener if it has been recovered from the store and not yet re-prepared.

Returns:

the remote listener associated with this EventRegistrationWatcher.

Throws:

IOException - if the listener can not be unmarshalled. May throw RemoteException if the call to the preparer does

ClassNotFoundException - if the listener needs to be unmarshalled and a necessary class can not be found.

SecurityException - if the prepareProxy call does.

addTemplateHandle

boolean addTemplateHandle(TemplateHandle h)

Associate a TemplateHandle with this object. May only be called once on any given EventRegistrationWatcher instance.

Specified by:

addTemplateHandle in class TransitionWatcher

Parameters:

h - The TemplateHandle associated with this watcher.

Returns:

true if the handle was succfully added, and false if the watcher has already been removed.

Throws:

NullPointerException - if h is null

setExpiration

public void setExpiration(long newExpiration)

Set the expiration time of this object. This method may be called before setTemplateHandle is called. Assumes locking is handled by the caller.

Specified by:

setExpiration in interface LeasedResource

Parameters:

newExpiration - The expiration time.

getExpiration

public long getExpiration()

Description copied from class: TransitionWatcher

Get the expiration time of this object. This method may be called before addTemplateHandle is called. Assumes locking is handled by the caller.

Specified by:

getExpiration in interface LeasedResource

Specified by:

getExpiration in class TransitionWatcher

Returns:

The time (in milliseconds since the beginning of the epoch) when this watcher is no longer relevant.

getCookie

public Uuid getCookie()

Get the unique identifier associated with this object. This method may be called before setTemplateHandle is called.

Specified by:

getCookie in interface LeasedResource

Returns:

The unique identifier associated with this watcher.

cleanup

void cleanup(TemplateHandle owner,
             boolean expired)

Overridden by subclasses if there is any cleanup work they need to do as part of cancel or removeIfExpired. Called after releasing the lock on this. Will be called at most once.

Parameters:

owner - A reference to the owner.

expired - true if being called from removeIfExpired and false otherwise.

doRemove

private boolean doRemove(long now,
                         boolean doIt)

The heavy lifting of removing ourselves.

Parameters:

now - The current time (or a bit earlier).

doIt - If true ignore now and just remove this object.

Returns:

true if this call removed this object, false if it had already been done. Should be ignored if doIt is false.

removeIfExpired

void removeIfExpired(long now)

Description copied from class: TransitionWatcher

Remove this watcher from the system if it has expired. Responsible for calling the remove method of the associated TemplateHandle. This method can be called more than once, though second and subsequent calls may have no effect.

Specified by:

removeIfExpired in class TransitionWatcher

Parameters:

now - An estimate of the current time that must be less than or equal to the current time.

cancel

public boolean cancel()

Description copied from interface: EventRegistrationRecord

Make sure this object will be removed from the system independent of the expiration time.

Specified by:

cancel in interface EventRegistrationRecord

Returns:

true if this call was the first removal attempt.