org.apache.flink.runtime.operators.udf.RangeBoundaryBuilder 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.flink.runtime.operators.udf;
import org.apache.flink.api.common.functions.RichMapPartitionFunction;
import org.apache.flink.api.common.typeutils.TypeComparator;
import org.apache.flink.api.common.typeutils.TypeComparatorFactory;
import org.apache.flink.util.Collector;
import java.util.ArrayList;
import java.util.Collections;
import java.util.Comparator;
import java.util.List;
/**
* Build RangeBoundaries with input records. First, sort the input records, and then select
* the boundaries with same interval.
*
* @param
*/
public class RangeBoundaryBuilder extends RichMapPartitionFunction {
private int parallelism;
private final TypeComparatorFactory comparatorFactory;
public RangeBoundaryBuilder(TypeComparatorFactory comparator, int parallelism) {
this.comparatorFactory = comparator;
this.parallelism = parallelism;
}
@Override
public void mapPartition(Iterable values, Collector out) throws Exception {
final TypeComparator comparator = this.comparatorFactory.createComparator();
List sampledData = new ArrayList<>();
for (T value : values) {
sampledData.add(value);
}
Collections.sort(sampledData, new Comparator() {
@Override
public int compare(T first, T second) {
return comparator.compare(first, second);
}
});
int boundarySize = parallelism - 1;
Object[][] boundaries = new Object[boundarySize][];
if (sampledData.size() > 0) {
double avgRange = sampledData.size() / (double) parallelism;
int numKey = comparator.getFlatComparators().length;
for (int i = 1; i < parallelism; i++) {
T record = sampledData.get((int) (i * avgRange));
Object[] keys = new Object[numKey];
comparator.extractKeys(record, keys, 0);
boundaries[i-1] = keys;
}
}
out.collect(boundaries);
}
}