Rio Project 4.2 API Documentation

org.rioproject.event
Class EventHandler

java.lang.Object
  org.rioproject.event.EventHandler

Direct Known Subclasses:

DispatchEventHandler, RoundRobinEventHandler

public abstract class EventHandler
extends Object

The EventHandler is an abstract class which handles the basic event plumbing. The EventHandler sets up a LandLordLessor for the event type and creates leased event registrations for event registrants

Author:

Dennis Reedy

Nested Class Summary

protected static class

EventHandler.EventRegistrationResource Container class for event registration objects which are created and behave as the resource that is being leased and controlled by the ServiceResource

Field Summary

protected EventDescriptor	descriptor
protected long	ektime
protected LandlordLessor	landlord
protected LeasedListManager	resourceMgr
static String	RESPONSE_WATCH
protected StopWatch	responseWatch
protected long	sendTime
protected int	sent
protected long	sequenceNumber The sequence number is an increasing value that will act as a hint to the number of occurances of an event type.
protected long	sktime
protected int	step
protected long	t0
protected long	t1
protected float	tmp
protected WatchDataSourceRegistry	watchRegistry

Constructor Summary

EventHandler(EventDescriptor descriptor)
Use this constructor to create an EventHandler for a given EventDescriptor with a LandlordLessor created with default values used for LeasePeriodPolicy

EventHandler(EventDescriptor descriptor, Configuration config)
Use this constructor to create an EventHandler for a given EventDescriptor with a LandlordLessor created with specific values used for LeaseDurationPolicy.

Method Summary

void	createWatch(WatchDataSourceRegistry watchRegistry) Create a response time watch for this EventHandler, which will track the response time for event consumers, measured by how long each fire() invocation takes
void	destroyWatch() Destroys the response time watch.
abstract void	fire(RemoteServiceEvent event) The fire method must be overridden by classes that extend this EventHandler, hence the reason the method is declared abstract.
protected ServiceResource	getNextServiceResource() Used to get the next ServiceResource from a LandlordLessor
int	getRegistrantCount() Gets the total number of ServiceResource instances contained by the LandlordLessor used by this EventHandler
Watch	getWatch() Get the response time watch for this EventHandler
protected void	printStats() Convenience method to print statisitics for every thousand events sent.
EventRegistration	register(Object eventSource, RemoteEventListener listener, MarshalledObject handback, long duration) Registers a RemoteEventListener for this event type.
void	terminate() Terminates this EventHandler.

Methods inherited from class java.lang.Object

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

Field Detail

descriptor

protected EventDescriptor descriptor

landlord

protected LandlordLessor landlord

sent

protected int sent

sktime

protected long sktime

ektime

protected long ektime

tmp

protected float tmp

responseWatch

protected StopWatch responseWatch

watchRegistry

protected WatchDataSourceRegistry watchRegistry

resourceMgr

protected LeasedListManager resourceMgr

RESPONSE_WATCH

public static final String RESPONSE_WATCH

See Also:

Constant Field Values

step

protected int step

t0

protected long t0

t1

protected long t1

sendTime

protected long sendTime

sequenceNumber

protected long sequenceNumber

The sequence number is an increasing value that will act as a hint to the number of occurances of an event type. The sequence number should differ if and only if the RemoteEvent objects are a response to different events. The sequence number should be increased only afetr an event has been sent

Constructor Detail

EventHandler

public EventHandler(EventDescriptor descriptor)
             throws Exception

Use this constructor to create an EventHandler for a given EventDescriptor with a LandlordLessor created with default values used for LeasePeriodPolicy

Parameters:

descriptor - EventDescriptor for the event to handle

Throws:

Exception - If a landlord lease manager cannot be created

EventHandler

public EventHandler(EventDescriptor descriptor,
                    Configuration config)
             throws Exception

Use this constructor to create an EventHandler for a given EventDescriptor with a LandlordLessor created with specific values used for LeaseDurationPolicy. If either of the values specified for the lease duration are null defaults will be used to create the LandlordLessor.

Parameters:

descriptor - EventDescriptor for the event to handle

config - A Configuration object

Throws:

Exception - If a landlord lease manager cannot be created

Method Detail

register

public EventRegistration register(Object eventSource,
                                  RemoteEventListener listener,
                                  MarshalledObject handback,
                                  long duration)
                           throws LeaseDeniedException

Registers a RemoteEventListener for this event type. This method will be delegated from the EventProducer#register method invocation

Parameters:

eventSource - The event source

listener - RemoteEventListener

handback - MarshalledObject

duration - Requested EventRegistration lease

Returns:

EventRegistration

Throws:

LeaseDeniedException - If the lease manager denies the lease

terminate

public void terminate()

Terminates this EventHandler. This causes all event registrant leases to be cancelled , and if any watches have been created those watches will be destroyed

createWatch

public void createWatch(WatchDataSourceRegistry watchRegistry)

Create a response time watch for this EventHandler, which will track the response time for event consumers, measured by how long each fire() invocation takes

Parameters:

watchRegistry - The WatchRegistry to register the StopWatch

destroyWatch

public void destroyWatch()

Destroys the response time watch. Once this method is called the watches will be rendered useless

getWatch

public Watch getWatch()

Get the response time watch for this EventHandler

Returns:

The response time StopWatch. If the watch was not created this method returns null

fire

public abstract void fire(RemoteServiceEvent event)
                   throws NoEventConsumerException

The fire method must be overridden by classes that extend this EventHandler, hence the reason the method is declared abstract.

Parameters:

event - The event to send

Throws:

NoEventConsumerException - This method may choose to throw a NoEventConsumerException if there are no event consumers registered

getRegistrantCount

public int getRegistrantCount()

Gets the total number of ServiceResource instances contained by the LandlordLessor used by this EventHandler

Returns:

The registrant count

getNextServiceResource

protected ServiceResource getNextServiceResource()

Used to get the next ServiceResource from a LandlordLessor

Returns:

The next ServiceResource contained by the LandlordLessor. If there are no ServiceResource instances available in the LandlordLessor then a value a null is returned

printStats

protected void printStats()

Convenience method to print statisitics for every thousand events sent. This method will only print result if the -Dorg.rioproject.debug flag is set