Package com.streambase.liveview.client

Class SnapshotQueryListener

java.lang.Object

com.streambase.liveview.client.SnapshotQueryListener

All Implemented Interfaces:

QueryListener, SnapshotResult, Closeable, AutoCloseable, EventListener

public final class SnapshotQueryListener
extends Object
implements SnapshotResult, QueryListener

A Convenience implementation of QueryListener that provides a pull based iterator pattern for iterating over snapshot queries. This should be used with snapshot queries only. Snapshots that hit the row limit are ended without any special notification.

Constructor Summary

Constructors

Constructor	Description
SnapshotQueryListener()
SnapshotQueryListener(int dataQueueCapacity)

Method Summary

Modifier and Type	Method	Description
void	close()	closes any resource associated with the snapshot result
void	deleteBegin(BeginDeleteEvent event)	Event to indicate the start of delete query.
void	deleteEnd(EndDeleteEvent event)	Event to indicate the delete query is complete.
void	exceptionRaised(QueryExceptionEvent event)	Event when an exception occurs during the query.
List<Schema.Field>	getFields()	Retrieves the fields describing the tuples that will be returned.
boolean	hasNext()	See if there are more tuples to retrieve.
Tuple	next()	Retrieves the next tuple in the result.
void	queryClosed(QueryClosedEvent event)	Event when a query being listened to is closed.
void	setQuery(Query queryImpl)
void	snapshotBegin(BeginSnapshotEvent event)	Event to indicate the start of the result snapshot.
void	snapshotEnd(EndSnapshotEvent event)	Event to indicate the query snapshot is complete.
void	tupleAdded(TupleAddedEvent event)	Event when a new tuple is added to the result.
void	tupleRemoved(TupleRemovedEvent event)	Event when an existing tuple is removed from the result.
void	tupleUpdated(TupleUpdatedEvent event)	Event when an existing tuple in the result is updated.

Methods inherited from class java.lang.Object

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

Methods inherited from interface com.streambase.liveview.client.QueryListener

aggMarkBegin, aggMarkEnd

Constructor Detail

SnapshotQueryListener

public SnapshotQueryListener()

SnapshotQueryListener

public SnapshotQueryListener(int dataQueueCapacity)

Method Detail

getFields

public List<Schema.Field> getFields()
                             throws LiveViewException

Retrieves the fields describing the tuples that will be returned.

Specified by:

getFields in interface SnapshotResult

Returns:

the fields describing the tuples

Throws:

LiveViewException - if exception occurs on the Query

hasNext

public boolean hasNext()
                throws LiveViewException

See if there are more tuples to retrieve. If there are not currently any Tuples waiting to be read, this will block until either the next Tuple or the Snapshot end arrives.

Specified by:

hasNext in interface SnapshotResult

Returns:

true if more tuples exist in result

Throws:

LiveViewException

next

public Tuple next()
           throws LiveViewException

Retrieves the next tuple in the result. If there are not currently any Tuples waiting to be read, this will block until either the next Tuple or the Snapshot end arrives.

Specified by:

next in interface SnapshotResult

Returns:

the next tuple

Throws:

LiveViewException - if exception occurs on the Query

tupleAdded

public void tupleAdded(TupleAddedEvent event)

Event when a new tuple is added to the result.

Specified by:

tupleAdded in interface QueryListener

Parameters:

event - add event

tupleUpdated

public void tupleUpdated(TupleUpdatedEvent event)

Event when an existing tuple in the result is updated.

Specified by:

tupleUpdated in interface QueryListener

Parameters:

event - update event

tupleRemoved

public void tupleRemoved(TupleRemovedEvent event)

Event when an existing tuple is removed from the result.

Specified by:

tupleRemoved in interface QueryListener

Parameters:

event - remove event

snapshotBegin

public void snapshotBegin(BeginSnapshotEvent event)

Event to indicate the start of the result snapshot. This is the first method called when a query starts returning results, but this method is also called to indicate a reset (a complete restart of the query.)

Specified by:

snapshotBegin in interface QueryListener

Parameters:

event - snapshot begin

snapshotEnd

public void snapshotEnd(EndSnapshotEvent event)

Event to indicate the query snapshot is complete.

Specified by:

snapshotEnd in interface QueryListener

Parameters:

event - snapshot end

exceptionRaised

public void exceptionRaised(QueryExceptionEvent event)

Event when an exception occurs during the query. Since 1.3, reaching the row limit is considered an exception.

Specified by:

exceptionRaised in interface QueryListener

Parameters:

event - exception event

queryClosed

public void queryClosed(QueryClosedEvent event)

Event when a query being listened to is closed.

Specified by:

queryClosed in interface QueryListener

Parameters:

event - query closed event

setQuery

public void setQuery(Query queryImpl)

close

public void close()

Description copied from interface: SnapshotResult

closes any resource associated with the snapshot result

Specified by:

close in interface AutoCloseable

Specified by:

close in interface Closeable

Specified by:

close in interface SnapshotResult

deleteBegin

public void deleteBegin(BeginDeleteEvent event)

Description copied from interface: QueryListener

Event to indicate the start of delete query.

Specified by:

deleteBegin in interface QueryListener

Parameters:

event - delete begin

deleteEnd

public void deleteEnd(EndDeleteEvent event)

Description copied from interface: QueryListener

Event to indicate the delete query is complete.

Specified by:

deleteEnd in interface QueryListener

Parameters:

event - delete end