/*
***************************************************************************************
* 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.epl.core;
import com.espertech.esper.client.EventBean;
import com.espertech.esper.epl.agg.service.AggregationService;
import com.espertech.esper.epl.expression.core.ExprEvaluatorContext;
import com.espertech.esper.metrics.instrumentation.InstrumentationHelper;
import java.util.Iterator;
import java.util.NoSuchElementException;
/**
* Iterator for group-by with aggregation.
*/
public class ResultSetAggregateGroupedIterator implements Iterator<EventBean> {
private final Iterator<EventBean> sourceIterator;
private final ResultSetProcessorAggregateGrouped resultSetProcessor;
private final AggregationService aggregationService;
private EventBean nextResult;
private final EventBean[] eventsPerStream;
private final ExprEvaluatorContext exprEvaluatorContext;
/**
* Ctor.
*
* @param sourceIterator is the parent iterator
* @param resultSetProcessor for constructing result rows
* @param aggregationService for pointing to the right aggregation row
* @param exprEvaluatorContext context for expression evalauation
*/
public ResultSetAggregateGroupedIterator(Iterator<EventBean> sourceIterator, ResultSetProcessorAggregateGrouped resultSetProcessor, AggregationService aggregationService, ExprEvaluatorContext exprEvaluatorContext) {
this.sourceIterator = sourceIterator;
this.resultSetProcessor = resultSetProcessor;
this.aggregationService = aggregationService;
eventsPerStream = new EventBean[1];
this.exprEvaluatorContext = exprEvaluatorContext;
}
public boolean hasNext() {
if (nextResult != null) {
return true;
}
findNext();
if (nextResult != null) {
return true;
}
return false;
}
public EventBean next() {
if (nextResult != null) {
EventBean result = nextResult;
nextResult = null;
return result;
}
findNext();
if (nextResult != null) {
EventBean result = nextResult;
nextResult = null;
return result;
}
throw new NoSuchElementException();
}
private void findNext() {
while (sourceIterator.hasNext()) {
EventBean candidate = sourceIterator.next();
eventsPerStream[0] = candidate;
Object groupKey = resultSetProcessor.generateGroupKey(eventsPerStream, true);
aggregationService.setCurrentAccess(groupKey, exprEvaluatorContext.getAgentInstanceId(), null);
Boolean pass = true;
if (resultSetProcessor.getOptionalHavingNode() != null) {
if (InstrumentationHelper.ENABLED) {
InstrumentationHelper.get().qHavingClauseJoin(eventsPerStream);
}
pass = (Boolean) resultSetProcessor.getOptionalHavingNode().evaluate(eventsPerStream, true, exprEvaluatorContext);
if (InstrumentationHelper.ENABLED) {
InstrumentationHelper.get().aHavingClauseJoin(pass);
}
}
if (!pass) {
continue;
}
nextResult = resultSetProcessor.getSelectExprProcessor().process(eventsPerStream, true, true, exprEvaluatorContext);
break;
}
}
public void remove() {
throw new UnsupportedOperationException();
}
}