RelativeAccessByEventNIndex.java

/*
 ***************************************************************************************
 *  Copyright (C) 2006 EsperTech, Inc. All rights reserved.                            *
 *  http://www.espertech.com/esper                                                     *
 *  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.view.window;

import com.espertech.esper.client.EventBean;

import java.util.Collection;
import java.util.Iterator;

/**
 * Provides access to prior events given an event from which to count back, and an index to look at.
 */
public interface RelativeAccessByEventNIndex {
    /**
     * Returns the prior event to the given event counting back the number of events as supplied by index.
     *
     * @param theEvent is the event to count back from
     * @param index    is the number of events to go back
     * @return event
     */
    public EventBean getRelativeToEvent(EventBean theEvent, int index);

    public EventBean getRelativeToEnd(int index);

    public Iterator<EventBean> getWindowToEvent();

    public Collection<EventBean> getWindowToEventCollReadOnly();

    public int getWindowToEventCount();
}