/**************************************************************************************
* 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.epl.expression.ExprEvaluatorContext;
import com.espertech.esper.epl.join.exec.sorted.SortedAccessStrategy;
import com.espertech.esper.epl.join.exec.sorted.SortedAccessStrategyFactory;
import com.espertech.esper.epl.join.plan.QueryGraphValueEntryRange;
import com.espertech.esper.epl.join.table.EventTable;
import com.espertech.esper.epl.join.table.PropertySortedEventTable;
import java.util.Iterator;
import java.util.Set;
/**
* Index lookup strategy into a poll-based cache result.
*/
public class HistoricalIndexLookupStrategySorted implements HistoricalIndexLookupStrategy
{
private final SortedAccessStrategy strategy;
/**
* Ctor.
*/
public HistoricalIndexLookupStrategySorted(int lookupStream, QueryGraphValueEntryRange property)
{
strategy = SortedAccessStrategyFactory.make(false, lookupStream, -1, property, null);
}
public Iterator<EventBean> lookup(EventBean lookupEvent, EventTable indexTable, ExprEvaluatorContext context)
{
// The table may not be indexed as the cache may not actively cache, in which case indexing doesn't makes sense
if (indexTable instanceof PropertySortedEventTable)
{
PropertySortedEventTable index = (PropertySortedEventTable) indexTable;
Set<EventBean> events = strategy.lookup(lookupEvent, index, context);
if (events != null)
{
return events.iterator();
}
return null;
}
return indexTable.iterator();
}
public String toQueryPlan() {
return this.getClass().getSimpleName() + " strategy: " + strategy.toQueryPlan();
}
}