/**************************************************************************************
* 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.filter;
import com.espertech.esper.client.EventBean;
import com.espertech.esper.client.EventPropertyGetter;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import java.util.Collection;
import java.util.Map;
import java.util.TreeMap;
import java.util.concurrent.locks.ReadWriteLock;
import java.util.concurrent.locks.ReentrantReadWriteLock;
/**
* Index for filter parameter constants for the comparison operators (less, greater, etc).
* The implementation is based on the SortedMap implementation of TreeMap.
* The index only accepts numeric constants. It keeps a lower and upper bounds of all constants in the index
* for fast range checking, since the assumption is that frequently values fall within a range.
*/
public final class FilterParamIndexCompare extends FilterParamIndexLookupableBase
{
private final TreeMap<Object, EventEvaluator> constantsMap;
private final ReadWriteLock constantsMapRWLock;
private Double lowerBounds;
private Double upperBounds;
public FilterParamIndexCompare(FilterSpecLookupable lookupable, FilterOperator filterOperator) {
super(filterOperator, lookupable);
constantsMap = new TreeMap<Object, EventEvaluator>();
constantsMapRWLock = new ReentrantReadWriteLock();
if ((filterOperator != FilterOperator.GREATER) &&
(filterOperator != FilterOperator.GREATER_OR_EQUAL) &&
(filterOperator != FilterOperator.LESS) &&
(filterOperator != FilterOperator.LESS_OR_EQUAL))
{
throw new IllegalArgumentException("Invalid filter operator for index of " + filterOperator);
}
}
public final EventEvaluator get(Object filterConstant)
{
return constantsMap.get(filterConstant);
}
public final void put(Object filterConstant, EventEvaluator matcher)
{
constantsMap.put(filterConstant, matcher);
// Update bounds
Double constant = ((Number) filterConstant).doubleValue();
if ((lowerBounds == null) || (constant < lowerBounds))
{
lowerBounds = constant;
}
if ((upperBounds == null) || (constant > upperBounds))
{
upperBounds = constant;
}
}
public final boolean remove(Object filterConstant)
{
if (constantsMap.remove(filterConstant) == null)
{
return false;
}
updateBounds();
return true;
}
public final int size()
{
return constantsMap.size();
}
public final ReadWriteLock getReadWriteLock()
{
return constantsMapRWLock;
}
public final void matchEvent(EventBean theEvent, Collection<FilterHandle> matches)
{
Object propertyValue = lookupable.getGetter().get(theEvent);
if (propertyValue == null)
{
return;
}
// A undefine lower bound indicates an empty index
if (lowerBounds == null)
{
return;
}
FilterOperator filterOperator = this.getFilterOperator();
Double propertyValueDouble = ((Number) propertyValue).doubleValue();
// Based on current lower and upper bounds check if the property value falls outside - shortcut submap generation
if ((filterOperator == FilterOperator.GREATER) && (propertyValueDouble <= lowerBounds))
{
return;
}
else if ((filterOperator == FilterOperator.GREATER_OR_EQUAL) && (propertyValueDouble < lowerBounds))
{
return;
}
else if ((filterOperator == FilterOperator.LESS) && (propertyValueDouble >= upperBounds))
{
return;
}
else if ((filterOperator == FilterOperator.LESS_OR_EQUAL) && (propertyValueDouble > upperBounds))
{
return;
}
// Look up in table
constantsMapRWLock.readLock().lock();
try {
// Get the head or tail end of the map depending on comparison type
Map<Object, EventEvaluator> subMap;
if ((filterOperator == FilterOperator.GREATER) ||
(filterOperator == FilterOperator.GREATER_OR_EQUAL))
{
// At the head of the map are those with a lower numeric constants
subMap = constantsMap.headMap(propertyValue);
}
else
{
subMap = constantsMap.tailMap(propertyValue);
}
// All entries in the subMap are elgibile, with an exception
EventEvaluator exactEquals = null;
if (filterOperator == FilterOperator.LESS)
{
exactEquals = constantsMap.get(propertyValue);
}
for (EventEvaluator matcher : subMap.values())
{
// For the LESS comparison type we ignore the exactly equal case
// The subMap is sorted ascending, thus the exactly equals case is the first
if (exactEquals != null)
{
exactEquals = null;
continue;
}
matcher.matchEvent(theEvent, matches);
}
if (filterOperator == FilterOperator.GREATER_OR_EQUAL)
{
EventEvaluator matcher = constantsMap.get(propertyValue);
if (matcher != null)
{
matcher.matchEvent(theEvent, matches);
}
}
}
finally {
constantsMapRWLock.readLock().unlock();
}
}
private void updateBounds()
{
if (constantsMap.isEmpty())
{
lowerBounds = null;
upperBounds = null;
return;
}
lowerBounds = ((Number) constantsMap.firstKey()).doubleValue();
upperBounds = ((Number) constantsMap.lastKey()).doubleValue();
}
private static final Log log = LogFactory.getLog(FilterParamIndexCompare.class);
}