/*
* *************************************************************************************
* 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.enummethod.eval;
import com.espertech.esper.client.EventBean;
import com.espertech.esper.epl.expression.ExprEvaluator;
import com.espertech.esper.epl.expression.ExprEvaluatorContext;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Collections;
public class EnumEvalTake implements EnumEval {
private ExprEvaluator sizeEval;
private int numStreams;
public EnumEvalTake(ExprEvaluator sizeEval, int numStreams) {
this.sizeEval = sizeEval;
this.numStreams = numStreams;
}
public int getStreamNumSize() {
return numStreams;
}
public Object evaluateEnumMethod(EventBean[] eventsLambda, Collection target, boolean isNewData, ExprEvaluatorContext context) {
Object sizeObj = sizeEval.evaluate(eventsLambda, isNewData, context);
if (sizeObj == null) {
return null;
}
if (target.isEmpty()) {
return target;
}
int size = ((Number) sizeObj).intValue();
if (size <= 0) {
return Collections.emptyList();
}
if (target.size() < size) {
return target;
}
if (size == 1) {
return Collections.singletonList(target.iterator().next());
}
ArrayList<Object> result = new ArrayList<Object>(size);
for (Object next : target) {
if (result.size() >= size) {
break;
}
result.add(next);
}
return result;
}
}