LastPostObserverView.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.view.internal;

import java.util.Iterator;

import com.espertech.esper.view.ViewSupport;
import com.espertech.esper.view.CloneableView;
import com.espertech.esper.view.View;
import com.espertech.esper.client.EventType;
import com.espertech.esper.client.EventBean;

/**
 * A view that retains the last update.
 */
public final class LastPostObserverView extends ViewSupport implements CloneableView
{
    private final int streamId;
    private LastPostObserver observer;

    /**
     * Ctor.
     * @param streamId - number of the stream for which the view buffers the generated events.
     */
    public LastPostObserverView(int streamId)
    {
        this.streamId = streamId;
    }

    /**
     * Set an observer.
     * @param observer to be called when results are available
     */
    public void setObserver(LastPostObserver observer)
    {
        this.observer = observer;
    }

    public View cloneView()
    {
        return new LastPostObserverView(streamId);
    }

    public final EventType getEventType()
    {
        return parent.getEventType();
    }

    public final Iterator<EventBean> iterator()
    {
        return parent.iterator();
    }

    public final void update(EventBean[] newData, EventBean[] oldData)
    {
        if (observer != null)
        {
            observer.newData(streamId, newData, oldData);
        }
    }
}