/*
* *************************************************************************************
* Copyright (C) 2008 EsperTech, Inc. All rights reserved. *
* http://esper.codehaus.org *
* http://www.espertech.com *
* ---------------------------------------------------------------------------------- *
* The software in this package is published under the terms of the GPL license *
* a copy of which has been included with this distribution in the license.txt file. *
* *************************************************************************************
*/
package com.espertech.esper.client.hook;
import com.espertech.esper.client.EventBean;
import java.util.Set;
/**
* Represents a lookup strategy object that an EPL statement that queries a virtual data window obtains
* to perform read operations into the virtual data window.
* <p>
* An instance is associated to each EPL statement querying (join, subquery, on-action etc.) the virtual data window.
*/
public interface VirtualDataWindowLookup {
/**
* Invoked by an EPL statement that queries a virtual data window to perform a lookup.
* <p>
* Keys passed are the actual query lookup values.
* @param keys lookup values
* @param eventsPerStream input events for the lookup
* @return set of events
*/
public Set<EventBean> lookup(Object[] keys, EventBean[] eventsPerStream);
}