blob: 9b0523c57f59fc73116e95d2e2978ae8e059079c [file] [log] [blame]
/*
* Copyright 2016, Yahoo! Inc.
* Licensed under the terms of the Apache License 2.0. See LICENSE file at the project root for terms.
*/
package com.yahoo.sketches.hive.quantiles;
import java.util.Comparator;
import org.apache.hadoop.hive.ql.exec.Description;
import org.apache.hadoop.hive.ql.exec.UDF;
import org.apache.hadoop.io.BytesWritable;
import com.yahoo.memory.Memory;
import com.yahoo.sketches.ArrayOfStringsSerDe;
import com.yahoo.sketches.quantiles.ItemsSketch;
@Description(name = "GetK", value = "_FUNC_(sketch)",
extended = " Returns parameter K from a given ItemsSketch<String> sketch.")
@SuppressWarnings("javadoc")
public class GetKFromStringsSketchUDF extends UDF {
/**
* Returns parameter K from a given sketch
* @param serializedSketch serialized sketch
* @return parameter K
*/
public Integer evaluate(final BytesWritable serializedSketch) {
if (serializedSketch == null) { return null; }
final ItemsSketch<String> sketch = ItemsSketch.getInstance(
Memory.wrap(serializedSketch.getBytes()),
Comparator.naturalOrder(),
new ArrayOfStringsSerDe()
);
return sketch.getK();
}
}