/*
* 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.flink.api.java.summarize.aggregation;
import org.apache.flink.annotation.Internal;
import org.apache.flink.api.java.tuple.Tuple;
/**
* Aggregate tuples using an array of aggregators, one for each "column" or position within the Tuple.
*/
@Internal
public class TupleSummaryAggregator<R extends Tuple> implements Aggregator<Tuple,R> {
private static final long serialVersionUID = 1L;
private final Aggregator[] columnAggregators;
public TupleSummaryAggregator(Aggregator[] columnAggregators) {
this.columnAggregators = columnAggregators;
}
@Override
@SuppressWarnings("unchecked")
public void aggregate(Tuple value) {
for(int i = 0; i < columnAggregators.length; i++) {
columnAggregators[i].aggregate(value.getField(i));
}
}
@Override
@SuppressWarnings("unchecked")
public void combine(Aggregator<Tuple, R> other) {
TupleSummaryAggregator tupleSummaryAggregator = (TupleSummaryAggregator) other;
for( int i = 0; i < columnAggregators.length; i++) {
columnAggregators[i].combine(tupleSummaryAggregator.columnAggregators[i]);
}
}
@Override
@SuppressWarnings("unchecked")
public R result() {
try {
Class tupleClass = Tuple.getTupleClass(columnAggregators.length);
R tuple = (R) tupleClass.newInstance();
for(int i = 0; i < columnAggregators.length; i++) {
tuple.setField(columnAggregators[i].result(), i);
}
return tuple;
}
catch (InstantiationException | IllegalAccessException e) {
throw new RuntimeException("Unexpected error instantiating Tuple class for aggregation results", e);
}
}
}