/**************************************************************************************
* 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.agg;
import com.espertech.esper.client.EventBean;
import com.espertech.esper.collection.ArrayEventIterator;
import java.util.*;
/**
* Implementation of access function for single-stream (not joins).
*/
public class AggregationAccessJoinImpl implements AggregationAccess
{
private int streamId;
private LinkedHashMap<EventBean, Integer> refSet = new LinkedHashMap<EventBean, Integer>();
private EventBean[] array;
/**
* Ctor.
* @param streamId stream id
*/
public AggregationAccessJoinImpl(int streamId)
{
this.streamId = streamId;
}
public void clear() {
refSet.clear();
array = null;
}
public void applyEnter(EventBean[] eventsPerStream)
{
EventBean theEvent = eventsPerStream[streamId];
if (theEvent == null) {
return;
}
array = null;
Integer value = refSet.get(theEvent);
if (value == null)
{
refSet.put(theEvent, 1);
return;
}
value++;
refSet.put(theEvent, value);
}
public void applyLeave(EventBean[] eventsPerStream)
{
EventBean theEvent = eventsPerStream[streamId];
if (theEvent == null) {
return;
}
array = null;
Integer value = refSet.get(theEvent);
if (value == null)
{
return;
}
if (value == 1)
{
refSet.remove(theEvent);
return;
}
value--;
refSet.put(theEvent, value);
}
public EventBean getFirstNthValue(int index) {
if (index < 0) {
return null;
}
if (refSet.isEmpty()) {
return null;
}
if (index >= refSet.size()) {
return null;
}
if (array == null) {
initArray();
}
return array[index];
}
public EventBean getLastNthValue(int index) {
if (index < 0) {
return null;
}
if (refSet.isEmpty()) {
return null;
}
if (index >= refSet.size()) {
return null;
}
if (array == null) {
initArray();
}
return array[array.length - index - 1];
}
public EventBean getFirstValue() {
if (refSet.isEmpty()) {
return null;
}
return refSet.entrySet().iterator().next().getKey();
}
public EventBean getLastValue()
{
if (refSet.isEmpty()) {
return null;
}
if (array == null) {
initArray();
}
return array[array.length - 1];
}
public Iterator<EventBean> iterator()
{
if (array == null) {
initArray();
}
return new ArrayEventIterator(array);
}
public Collection<EventBean> collectionReadOnly() {
if (array == null) {
initArray();
}
return Arrays.asList(array);
}
public int size()
{
return refSet.size();
}
private void initArray() {
Set<EventBean> events = refSet.keySet();
array = events.toArray(new EventBean[events.size()]);
}
}