| /* |
| * 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.datasketches.hive.cpc; |
| |
| import static org.apache.datasketches.Util.DEFAULT_UPDATE_SEED; |
| |
| import org.apache.datasketches.cpc.CpcSketch; |
| import org.apache.datasketches.cpc.CpcUnion; |
| import org.apache.datasketches.memory.Memory; |
| import org.apache.hadoop.hive.ql.exec.UDF; |
| import org.apache.hadoop.io.BytesWritable; |
| |
| /** |
| * Hive union sketch UDF. |
| */ |
| public class UnionSketchUDF extends UDF { |
| |
| /** |
| * Union two sketches given explicit lgK and seed |
| * |
| * @param firstSketch |
| * first sketch to be unioned. |
| * @param secondSketch |
| * second sketch to be unioned. |
| * @param lgK |
| * final output lgK |
| * This must be between 4 and 26. |
| * @param seed |
| * update seed |
| * @return resulting sketch of union. |
| */ |
| public BytesWritable evaluate(final BytesWritable firstSketch, final BytesWritable secondSketch, |
| final int lgK, final long seed) { |
| |
| final CpcUnion union = new CpcUnion(lgK, seed); |
| |
| if (firstSketch != null) { |
| union.update(CpcSketch.heapify(Memory.wrap(firstSketch.getBytes()), seed)); |
| } |
| |
| if (secondSketch != null) { |
| union.update(CpcSketch.heapify(Memory.wrap(secondSketch.getBytes()), seed)); |
| } |
| |
| return new BytesWritable(union.getResult().toByteArray()); |
| } |
| |
| /** |
| * Union two sketches given explicit lgK and using default seed |
| * |
| * @param firstSketch |
| * first sketch to be unioned. |
| * @param secondSketch |
| * second sketch to be unioned. |
| * @param lgK |
| * final output lgK |
| * This must be between 4 and 26. |
| * @return resulting sketch of union. |
| */ |
| public BytesWritable evaluate(final BytesWritable firstSketch, final BytesWritable secondSketch, |
| final int lgK) { |
| return evaluate(firstSketch, secondSketch, lgK, DEFAULT_UPDATE_SEED); |
| } |
| |
| /** |
| * Union two sketches using default lgK an seed |
| * |
| * @param firstSketch |
| * first sketch to be unioned. |
| * @param secondSketch |
| * second sketch to be unioned. |
| * @return resulting sketch of union. |
| */ |
| public BytesWritable evaluate(final BytesWritable firstSketch, final BytesWritable secondSketch) { |
| return evaluate(firstSketch, secondSketch, SketchEvaluator.DEFAULT_LG_K, DEFAULT_UPDATE_SEED); |
| } |
| |
| } |