/**************************************************************************************
* 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.join.base;
import com.espertech.esper.client.EventBean;
import com.espertech.esper.client.EventType;
import com.espertech.esper.epl.expression.ExprEvaluator;
import com.espertech.esper.epl.expression.ExprEvaluatorContext;
import com.espertech.esper.epl.expression.ExprNodeUtility;
import com.espertech.esper.epl.join.plan.QueryGraphValueEntryHashKeyed;
import com.espertech.esper.epl.join.table.EventTable;
import com.espertech.esper.epl.join.table.PropertyIndexedEventTable;
import java.util.Iterator;
import java.util.List;
import java.util.Set;
/**
* Index lookup strategy into a poll-based cache result.
*/
public class HistoricalIndexLookupStrategyIndex implements HistoricalIndexLookupStrategy
{
private final EventBean[] eventsPerStream;
private final int lookupStream;
private final ExprEvaluator[] evaluators;
/**
* Ctor.
* @param eventType - event type to expect for lookup
*/
public HistoricalIndexLookupStrategyIndex(EventType eventType, int lookupStream, List<QueryGraphValueEntryHashKeyed> hashKeys)
{
this.evaluators = new ExprEvaluator[hashKeys.size()];
for (int i = 0; i < hashKeys.size(); i++) {
evaluators[i] = hashKeys.get(i).getKeyExpr().getExprEvaluator();
}
this.eventsPerStream = new EventBean[lookupStream + 1];
this.lookupStream = lookupStream;
}
public Iterator<EventBean> lookup(EventBean lookupEvent, EventTable[] indexTable, ExprEvaluatorContext exprEvaluatorContext)
{
// The table may not be indexed as the cache may not actively cache, in which case indexing doesn't makes sense
if (indexTable[0] instanceof PropertyIndexedEventTable)
{
PropertyIndexedEventTable index = (PropertyIndexedEventTable) indexTable[0];
Object[] keys = getKeys(lookupEvent, exprEvaluatorContext);
Set<EventBean> events = index.lookup(keys);
if (events != null)
{
return events.iterator();
}
return null;
}
return indexTable[0].iterator();
}
private Object[] getKeys(EventBean theEvent, ExprEvaluatorContext exprEvaluatorContext)
{
eventsPerStream[lookupStream] = theEvent;
Object[] keys = new Object[evaluators.length];
for (int i = 0; i < evaluators.length; i++) {
keys[i] = evaluators[i].evaluate(eventsPerStream, true, exprEvaluatorContext);
}
return keys;
}
public String toQueryPlan() {
return this.getClass().getSimpleName() + " evaluators " + ExprNodeUtility.printEvaluators(evaluators);
}
}