paul-rogers commented on a change in pull request #1870: DRILL-7359: Add support for DICT type in RowSet Framework URL: https://github.com/apache/drill/pull/1870#discussion_r341882388
########## File path: exec/vector/src/main/java/org/apache/drill/exec/vector/accessor/DictWriter.java ########## @@ -0,0 +1,28 @@ +/* + * 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.vector.accessor; + +/** + * Dict writer is represented as an array of Maps (Array with Tuple entry). + */ +public interface DictWriter extends ArrayWriter { + ValueType keyType(); + ObjectType valueType(); + ScalarWriter keyWriter(); + ObjectWriter valueWriter(); Review comment: The above is getting close, but it does introduce an ambiguity. The array writer already has the following members: ``` ObjectType entryType(); ObjectWriter entry(); ``` Along with some other helpers. In the `DictWriter` case, it is not clear that I could use this object a `ArrayWriter`. Which of above does the entry correspond to? Might it be better to have `DictWriter` inherit directly from `ColumnWriter` so you can define clean semantics? If it is worth having common functionality (only `save()` would be common), we could define a `SequenceWriter` which is the base of `ArrayWriter` and `DictWriter`. Or, you could change `ArrayWriter` to add a new element writer; a `DictEntry` which would provide the methods above. That is: ``` ArrayWriter aw = reader.get('myDict').array(); DictWriter dw = aw.dict(); for (int i = 0; i < kvCount; i++) { dw.keyWriter().setString("key + " i); dw.valueWriter().union().setInt(i); aw.save(); } ``` That is, a Dict is an array. The entries in the array are key/value pairs. The key is a scalar, the value is of some type (above I suggested a Union -- with all the problems that Unions bring.) ---------------------------------------------------------------- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. For queries about this service, please contact Infrastructure at: us...@infra.apache.org With regards, Apache Git Services
