/*
* Copyright 2013 Future Systems
*
* Licensed 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.araqne.logdb.query.aggregator;
import java.util.List;
import org.araqne.logdb.Row;
import org.araqne.logdb.query.command.NumberUtil;
import org.araqne.logdb.query.expr.Expression;
public class Sum extends AbstractAggregationFunction {
protected Number sum = 0L;
private Expression expr;
public Sum(List<Expression> exprs) {
super(exprs);
this.expr = exprs.get(0);
}
@Override
public String getName() {
return "sum";
}
@Override
public void apply(Row map) {
Object obj = expr.eval(map);
if (obj == null || !(obj instanceof Number))
return;
sum = NumberUtil.add(sum, obj);
}
@Override
public Object eval() {
return sum;
}
@Override
public void merge(AggregationFunction func) {
Sum other = (Sum) func;
this.sum = NumberUtil.add(sum, other.sum);
}
@Override
public void deserialize(Object[] values) {
this.sum = (Number) values[0];
}
@Override
public Object[] serialize() {
Object[] l = new Object[1];
l[0] = sum;
return l;
}
@Override
public void clean() {
sum = null;
}
@Override
public AggregationFunction clone() {
Sum s = new Sum(this.exprs);
s.sum = this.sum;
return s;
}
@Override
public String toString() {
return "sum(" + expr + ")";
}
@Override
public boolean canBeDistributed() {
return true;
}
@Override
public AggregationFunction mapper(List<Expression> exprs) {
return new Sum(exprs);
}
@Override
public AggregationFunction reducer(List<Expression> exprs) {
return new Sum(exprs);
}
}