org.apache.river.mercury

Class EventLogFactory.EventLogIteratorImpl

java.lang.Object

org.apache.river.mercury.EventLogFactory.EventLogIteratorImpl

All Implemented Interfaces:

EventLogIterator

Enclosing class:

EventLogFactory

private static class EventLogFactory.EventLogIteratorImpl
extends Object
implements EventLogIterator

Private class which implements the EventLogIterator interface. This class delegates to an EventLog for most of its functionality.

Field Summary

Fields

Modifier and Type	Field and Description
private EventLog	log The associated EventLog for this iterator
private Uuid	uuid The associated Uuid for this iterator

Constructor Summary

Constructors

Constructor and Description
EventLogIteratorImpl(Uuid id) Simple constructor that assigns the Uuid field to the appropriate internal field and creates a transient event log.
EventLogIteratorImpl(Uuid id, File logPath) Simple constructor that assigns the Uuid field to the appropriate internal field and creates a persistent EventLog object using the provided File argument.

Method Summary

Modifier and Type	Method and Description
void	add(RemoteEvent evt) Store the given RemoteEvent event.
void	destroy() Destroy the collection of stored events.
boolean	hasNext() Return true if there are any events in the collection and false otherwise.
void	init()
void	moveAhead(Object cookie) Effectively removes the last set of read events from the log.
RemoteEvent	next() Return the next event in the collection.
RemoteEventData[]	readAhead(int maxEvents) Return an array of RemoteEventData with a limit of maxEvents elements.
void	remove() Remove the event at the iterator's current cursor position.

Methods inherited from class java.lang.Object

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

Field Detail

uuid

private final Uuid uuid

The associated Uuid for this iterator

log

private EventLog log

The associated EventLog for this iterator

Constructor Detail

EventLogIteratorImpl

EventLogIteratorImpl(Uuid id,
                     File logPath)

Simple constructor that assigns the Uuid field to the appropriate internal field and creates a persistent EventLog object using the provided File argument.

EventLogIteratorImpl

EventLogIteratorImpl(Uuid id)

Simple constructor that assigns the Uuid field to the appropriate internal field and creates a transient event log.

Method Detail

init

public void init()
          throws IOException

Throws:

IOException

add

public void add(RemoteEvent evt)
         throws IOException,
                IllegalArgumentException

Description copied from interface: EventLogIterator

Store the given RemoteEvent event.

Specified by:

add in interface EventLogIterator

Throws:

IOException - if an I/O errors occurs

IllegalArgumentException

hasNext

public boolean hasNext()
                throws IOException

Description copied from interface: EventLogIterator

Return true if there are any events in the collection and false otherwise.

Specified by:

hasNext in interface EventLogIterator

Throws:

IOException - if an I/O errors occurs

next

public RemoteEvent next()
                 throws IOException,
                        ClassNotFoundException,
                        NoSuchElementException

Description copied from interface: EventLogIterator

Return the next event in the collection.

Specified by:

next in interface EventLogIterator

Throws:

IOException - if an I/O errors occurs

ClassNotFoundException - if there was a problem deserializing the stored RemoteEvent

NoSuchElementException - if there are no available RemoteEvents

remove

public void remove()
            throws IOException,
                   IllegalStateException

Description copied from interface: EventLogIterator

Remove the event at the iterator's current cursor position. It is expected that the cursor position will be updated to point to the next unread event object, if any, upon return from this method.

Specified by:

remove in interface EventLogIterator

Throws:

IOException - if an I/O errors occurs

IllegalStateException

readAhead

public RemoteEventData[] readAhead(int maxEvents)
                            throws IOException,
                                   ClassNotFoundException

Description copied from interface: EventLogIterator

Return an array of RemoteEventData with a limit of maxEvents elements. Note that readAhead is meant to be used in conjunction with moveAhead. Subsequent calls to readAhead with the same argument value will return the same set of events until moveAhead is called, which actually updates the read pointer to the next unread event (indicating that the previously read events were successfully processed).

Specified by:

readAhead in interface EventLogIterator

Parameters:

maxEvents - maximum number of events/elements to return

Throws:

IOException - if an I/O error occurs

ClassNotFoundException - if a class for the serialized object could not be found

moveAhead

public void moveAhead(Object cookie)
               throws IOException

Description copied from interface: EventLogIterator

Effectively removes the last set of read events from the log. It does this by advancing the read pointer to the next available event after the event associated with the provided cookie object.

Specified by:

moveAhead in interface EventLogIterator

Parameters:

cookie - object associated with event to read past. This object should have been obtained from a previous call to readAhead on this event log.

Throws:

IOException - if there was a problem advancing the read pointer.

destroy

public void destroy()
             throws IOException

Description copied from interface: EventLogIterator

Destroy the collection of stored events.

Specified by:

destroy in interface EventLogIterator

Throws:

IOException - if an I/O errors occurs