com.yahoo.sketches.hive.quantiles.GetKFromDoublesSketchUDF Maven / Gradle / Ivy
/*
* 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 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.quantiles.DoublesSketch;
@Description(name = "GetK", value = "_FUNC_(sketch)",
extended = " Returns parameter K from a given DoublesSketch sketch.")
public class GetKFromDoublesSketchUDF 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 DoublesSketch sketch = DoublesSketch.wrap(Memory.wrap(serializedSketch.getBytes()));
return sketch.getK();
}
}