com.intersystems.xep

Class EventQuery<E>

java.lang.Object

com.intersystems.xep.EventQuery<E>

Type Parameters:

E - type

public final class EventQuery<E>
extends Object

EventQuery.java can be used to retrieve, update and delete individual events from the database.

Method Summary

Modifier and Type	Method and Description
void	close() Closes the query.
void	deleteCurrent() Deletes the object most recently returned by getNext()
void	execute() Execute this XEP query.
E[]	executeAndFetchAll(int splitFactor) Executes the query and fetches all data.
List<E>	getAll() Gets all data in one fell swoop.
EventQueryIterator<E>	getIterator() Get an EventQueryIterator that can be used to iterate over query results.
E	getNext(E obj) Gets the next object.
void	setParameter(int index, Object value) Binds a parameter.
void	updateCurrent(E obj) Updates the object most recently returned by getNext().

Methods inherited from class java.lang.Object

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

Method Detail

setParameter

public final void setParameter(int index,
                               Object value)

Binds a parameter.

Parameters:

index - parameter index

value - parameter value

execute

public final void execute()

Execute this XEP query.

executeAndFetchAll

public final E[] executeAndFetchAll(int splitFactor)

Executes the query and fetches all data. IN case of the TCP/IP version and on multi-core machines setting the splitFactor parameter to anything between 3 and the total number of cores should speed up execution as the de-serialization will be done in parallel by using splitFactor cores/threads. Otherwise (using in-memory version or setting splitFactor to 2 or less, or when a full schema option is selected), this is equivalent to calling Execute followed by calling GetNext in a loop.

Parameters:

splitFactor - number of threads to use (should be greater than 2)

Returns:

all objects matching the query

getNext

public final E getNext(E obj)

Gets the next object.

Parameters:

obj - placeholder for the object to be returned

Returns:

next object, null if no more objects for this query

updateCurrent

public final void updateCurrent(E obj)

Updates the object most recently returned by getNext().

Parameters:

obj - object to be updated

deleteCurrent

public final void deleteCurrent()

Deletes the object most recently returned by getNext()

close

public final void close()

Closes the query.

getAll

public final List<E> getAll()

Gets all data in one fell swoop. Can be used to get all data that matches the given query. Can be used only after a query has been executed, and cannot be combined with calls to getNext. IMPORTANT: This is a convenience method. For best performance, if you need to process one element at the time only, always choose getNext instead. There is a high cost associated with maintaining a list of objects.

Returns:

List list of objects matching the query

getIterator

public final EventQueryIterator<E> getIterator()

Get an EventQueryIterator that can be used to iterate over query results. Note that one should always opt to use either the iterator, or direct approach (using getNext/updateCurrent). Mixing calls to iterator methods and direct EventQuery methods can result in unpredicted behavior. getIterator should be called right after a call to execute. EventQueryIterator is an implementation of java.util.Iterator

Returns:

EventQueryIterator iterator