/*
 ***************************************************************************************
 *  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.HashMap;
import java.util.Map;

/**
 * Provides random-access into window contents by event and index as a combination.
 */
public class RelativeAccessByEventNIndexGetterImpl implements IStreamRelativeAccess.IStreamRelativeAccessUpdateObserver, RelativeAccessByEventNIndexGetter {
    private final Map<EventBean, RelativeAccessByEventNIndex> accessorByEvent = new HashMap<EventBean, RelativeAccessByEventNIndex>();
    private final Map<RelativeAccessByEventNIndex, EventBean[]> eventsByAccessor = new HashMap<RelativeAccessByEventNIndex, EventBean[]>();

    public void updated(RelativeAccessByEventNIndex iStreamRelativeAccess, EventBean[] newData) {
        // remove data posted from the last update
        EventBean[] lastNewData = eventsByAccessor.get(iStreamRelativeAccess);
        if (lastNewData != null) {
            for (int i = 0; i < lastNewData.length; i++) {
                accessorByEvent.remove(lastNewData[i]);
            }
        }

        if (newData == null) {
            return;
        }

        // hold accessor per event for querying
        for (int i = 0; i < newData.length; i++) {
            accessorByEvent.put(newData[i], iStreamRelativeAccess);
        }

        // save new data for access to later removal
        eventsByAccessor.put(iStreamRelativeAccess, newData);
    }

    /**
     * Returns the access into window contents given an event.
     *
     * @param theEvent to which the method returns relative access from
     * @return buffer
     */
    public RelativeAccessByEventNIndex getAccessor(EventBean theEvent) {
        RelativeAccessByEventNIndex iStreamRelativeAccess = accessorByEvent.get(theEvent);
        if (iStreamRelativeAccess == null) {
            return null;
        }
        return iStreamRelativeAccess;
    }
}