org.apache.openjpa.kernel.exps.Avg Maven / Gradle / Ivy
/*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing,
* software distributed under the License is distributed on an
* "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
* KIND, either express or implied. See the License for the
* specific language governing permissions and limitations
* under the License.
*/
package org.apache.openjpa.kernel.exps;
import java.util.Collection;
import org.apache.openjpa.kernel.Filters;
/**
* Average values.
*
* @author Abe White
*/
class Avg
extends AggregateVal {
private static final long serialVersionUID = 1L;
/**
* Constructor. Provide the value to average.
*/
public Avg(Val val) {
super(val);
}
@Override
protected Class getType(Class c) {
return c;
}
@Override
protected Object operate(Collection os, Class c) {
if (os.isEmpty())
return null;
Object sum = Filters.convert(0, c);
Object cur;
int size = 0;
for (Object o : os) {
cur = o;
if (cur == null)
continue;
sum = Filters.add(sum, c, cur, c);
size++;
}
if (size == 0)
return null;
return Filters.divide(sum, c, size, int.class);
}
}