| /* |
| * 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.drill.exec.expr.fn.impl; |
| |
| import io.netty.buffer.DrillBuf; |
| import org.apache.drill.exec.expr.DrillSimpleFunc; |
| import org.apache.drill.exec.expr.annotations.FunctionTemplate; |
| import org.apache.drill.exec.expr.annotations.Output; |
| import org.apache.drill.exec.expr.annotations.Param; |
| import org.apache.drill.exec.vector.complex.reader.FieldReader; |
| import org.apache.drill.exec.vector.complex.writer.BaseWriter.ComplexWriter; |
| |
| import javax.inject.Inject; |
| |
| public class Mappify { |
| |
| /* |
| * The following function can be invoked when we want to convert a map to a repeated map where every |
| * with two fields in each entry: |
| * key: the name of the field in the original map and |
| * value: value of the field |
| * |
| * For eg, consider the following json file: |
| * |
| * {"foo": {"obj":1, "bar":10}} |
| * {"foo": {"obj":2, "bar":20}} |
| * |
| * Invoking mappify(foo) would result in the following output |
| * |
| * [{"key":"obj", "value":1}, {"key":"bar", "value":10}] |
| * [{"key":"obj", "value":2}, {"key":"bar", "value":20}] |
| * |
| * Currently this function only allows |
| * simple maps as input |
| * scalar value fields |
| * value fields need to be of the same data type |
| */ |
| @FunctionTemplate(names = {"mappify", "kvgen"}, scope = FunctionTemplate.FunctionScope.SIMPLE, isRandom = true) |
| public static class ConvertMapToKeyValuePairs implements DrillSimpleFunc { |
| |
| @Param FieldReader reader; |
| @Inject DrillBuf buffer; |
| @Output ComplexWriter writer; |
| |
| @Override |
| public void setup() { |
| } |
| |
| @Override |
| public void eval() { |
| buffer = org.apache.drill.exec.expr.fn.impl.MappifyUtility.mappify(reader, writer, buffer, "Mappify/kvgen"); |
| } |
| } |
| } |