NamedWindowOnUpdateView.java

/**************************************************************************************
 * 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.epl.named;

import com.espertech.esper.client.EventBean;
import com.espertech.esper.client.EventType;
import com.espertech.esper.collection.ArrayEventIterator;
import com.espertech.esper.collection.OneEventCollection;
import com.espertech.esper.epl.expression.ExprEvaluatorContext;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

import java.util.Iterator;

/**
 * View for the on-delete statement that handles removing events from a named window.
 */
public class NamedWindowOnUpdateView extends NamedWindowOnExprBaseView
{
    private static final Log log = LogFactory.getLog(NamedWindowOnUpdateView.class);

    private NamedWindowOnUpdateViewFactory parent;
    private EventBean[] lastResult;

    public NamedWindowOnUpdateView(NamedWindowLookupStrategy lookupStrategy, NamedWindowRootViewInstance rootView, ExprEvaluatorContext exprEvaluatorContext, NamedWindowOnUpdateViewFactory parent) {
        super(lookupStrategy, rootView, exprEvaluatorContext);
        this.parent = parent;
    }

    public void handleMatching(EventBean[] triggerEvents, EventBean[] matchingEvents)
    {
        if ((matchingEvents == null) || (matchingEvents.length == 0)){
            return;
        }
        EventBean[] eventsPerStream = new EventBean[3];

        OneEventCollection newData = new OneEventCollection();
        OneEventCollection oldData = new OneEventCollection();

        for (EventBean triggerEvent : triggerEvents) {
            eventsPerStream[1] = triggerEvent;
            for (EventBean matchingEvent : matchingEvents) {
                EventBean copy = parent.getUpdateHelper().update(matchingEvent, eventsPerStream, super.getExprEvaluatorContext());
                newData.add(copy);
                oldData.add(matchingEvent);
            }
        }

        if (!newData.isEmpty())
        {
            // Events to delete are indicated via old data
            this.rootView.update(newData.toArray(), oldData.toArray());

            // The on-delete listeners receive the events deleted, but only if there is interest
            if (parent.getStatementResultService().isMakeNatural() || parent.getStatementResultService().isMakeSynthetic()) {
                updateChildren(newData.toArray(), oldData.toArray());
            }
        }

        // Keep the last delete records
        lastResult = matchingEvents;
    }

    public EventType getEventType() {
        return rootView.getEventType();
    }

    public Iterator<EventBean> iterator() {
        return new ArrayEventIterator(lastResult);
    }
}