/**************************************************************************************
* 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.window;
import com.espertech.esper.client.EventBean;
import com.espertech.esper.client.EventType;
import com.espertech.esper.collection.OneEventCollection;
import com.espertech.esper.core.context.util.AgentInstanceViewFactoryChainContext;
import com.espertech.esper.metrics.instrumentation.InstrumentationHelper;
import com.espertech.esper.view.*;
import java.util.Iterator;
import java.util.LinkedHashSet;
/**
* A length-first view takes the first N arriving events. Further arriving insert stream events are disregarded until
* events are deleted.
* <p>
* Remove stream events delete from the data window.
*/
public class FirstLengthWindowView extends ViewSupport implements DataWindowView, CloneableView
{
protected final AgentInstanceViewFactoryChainContext agentInstanceViewFactoryContext;
private final FirstLengthWindowViewFactory lengthFirstFactory;
private final int size;
protected LinkedHashSet<EventBean> indexedEvents;
/**
* Ctor.
* @param size the first N events to consider
* @param lengthFirstWindowViewFactory for copying this view in a group-by
*/
public FirstLengthWindowView(AgentInstanceViewFactoryChainContext agentInstanceViewFactoryContext, FirstLengthWindowViewFactory lengthFirstWindowViewFactory, int size)
{
if (size < 1)
{
throw new IllegalArgumentException("Illegal argument for size of length window");
}
this.agentInstanceViewFactoryContext = agentInstanceViewFactoryContext;
this.lengthFirstFactory = lengthFirstWindowViewFactory;
this.size = size;
indexedEvents = new LinkedHashSet<EventBean>();
}
public View cloneView()
{
return lengthFirstFactory.makeView(agentInstanceViewFactoryContext);
}
/**
* Returns true if the window is empty, or false if not empty.
* @return true if empty
*/
public boolean isEmpty()
{
return indexedEvents.isEmpty();
}
/**
* Returns the size of the length window.
* @return size of length window
*/
public final int getSize()
{
return size;
}
public final EventType getEventType()
{
// The event type is the parent view's event type
return parent.getEventType();
}
public final void update(EventBean[] newData, EventBean[] oldData)
{
if (InstrumentationHelper.ENABLED) { InstrumentationHelper.get().qViewProcessIRStream(this, lengthFirstFactory.getViewName(), newData, oldData);}
OneEventCollection newDataToPost = null;
OneEventCollection oldDataToPost = null;
// add data points to the window as long as its not full, ignoring later events
if (newData != null)
{
for (EventBean aNewData : newData)
{
if (indexedEvents.size() < size)
{
if (newDataToPost == null)
{
newDataToPost = new OneEventCollection();
}
newDataToPost.add(aNewData);
indexedEvents.add(aNewData);
internalHandleAdded(aNewData);
}
}
}
if (oldData != null)
{
for (EventBean anOldData : oldData)
{
boolean removed = indexedEvents.remove(anOldData);
if (removed)
{
if (oldDataToPost == null)
{
oldDataToPost = new OneEventCollection();
}
oldDataToPost.add(anOldData);
internalHandleRemoved(anOldData);
}
}
}
// If there are child views, call update method
if ((this.hasViews()) && ((newDataToPost != null) || (oldDataToPost != null)))
{
EventBean[] nd = (newDataToPost != null) ? newDataToPost.toArray() : null;
EventBean[] od = (oldDataToPost != null) ? oldDataToPost.toArray() : null;
if (InstrumentationHelper.ENABLED) { InstrumentationHelper.get().qViewIndicate(this, lengthFirstFactory.getViewName(), nd, od);}
updateChildren(nd, od);
if (InstrumentationHelper.ENABLED) { InstrumentationHelper.get().aViewIndicate();}
}
if (InstrumentationHelper.ENABLED) { InstrumentationHelper.get().aViewProcessIRStream();}
}
public void internalHandleRemoved(EventBean anOldData) {
// no action required
}
public void internalHandleAdded(EventBean aNewData) {
// no action required
}
public final Iterator<EventBean> iterator()
{
return indexedEvents.iterator();
}
public final String toString()
{
return this.getClass().getName() + " size=" + size;
}
public void visitView(ViewDataVisitor viewDataVisitor) {
viewDataVisitor.visitPrimary(indexedEvents, true, lengthFirstFactory.getViewName(), null);
}
public LinkedHashSet<EventBean> getIndexedEvents() {
return indexedEvents;
}
}