/*
***************************************************************************************
* 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.enummethod.eval;
import com.espertech.esper.client.EventBean;
import com.espertech.esper.epl.expression.core.ExprEvaluator;
import com.espertech.esper.epl.expression.core.ExprEvaluatorContext;
import java.util.Collection;
import java.util.LinkedHashMap;
import java.util.Map;
public class EnumEvalMostLeastFrequentEvent extends EnumEvalBase implements EnumEval {
private final boolean isMostFrequent;
public EnumEvalMostLeastFrequentEvent(ExprEvaluator innerExpression, int streamCountIncoming, boolean mostFrequent) {
super(innerExpression, streamCountIncoming);
isMostFrequent = mostFrequent;
}
public Object evaluateEnumMethod(EventBean[] eventsLambda, Collection target, boolean isNewData, ExprEvaluatorContext context) {
Map<Object, Integer> items = new LinkedHashMap<Object, Integer>();
Collection<EventBean> beans = (Collection<EventBean>) target;
for (EventBean next : beans) {
eventsLambda[streamNumLambda] = next;
Object item = innerExpression.evaluate(eventsLambda, isNewData, context);
Integer existing = items.get(item);
if (existing == null) {
existing = 1;
} else {
existing++;
}
items.put(item, existing);
}
return getResult(items, isMostFrequent);
}
protected static Object getResult(Map<Object, Integer> items, boolean mostFrequent) {
if (mostFrequent) {
Object maxKey = null;
int max = Integer.MIN_VALUE;
for (Map.Entry<Object, Integer> entry : items.entrySet()) {
if (entry.getValue() > max) {
maxKey = entry.getKey();
max = entry.getValue();
}
}
return maxKey;
}
int min = Integer.MAX_VALUE;
Object minKey = null;
for (Map.Entry<Object, Integer> entry : items.entrySet()) {
if (entry.getValue() < min) {
minKey = entry.getKey();
min = entry.getValue();
}
}
return minKey;
}
}