| /* |
| * Copyright 2019, Verizon Media. |
| * Licensed under the terms of the Apache License 2.0. See LICENSE file at the project root for terms. |
| */ |
| |
| package com.yahoo.sketches.hive.hll; |
| |
| 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.hll.HllSketch; |
| |
| @Description( |
| name = "SketchToString", |
| value = "_FUNC_(sketch)", |
| extended = "Returns an human-readable summary of a given HllSketch.") |
| public class SketchToStringUDF extends UDF { |
| |
| /** |
| * Get a human-readable summary of a given HllSketch |
| * @param serializedSketch HllSketch in a serialized binary form |
| * @return text summary |
| */ |
| public String evaluate(final BytesWritable serializedSketch) { |
| if (serializedSketch == null) { return null; } |
| final HllSketch sketch = HllSketch.wrap(Memory.wrap(serializedSketch.getBytes())); |
| return sketch.toString(); |
| } |
| |
| } |