dawidwys commented on a change in pull request #8006: [FLINK-11068][table] Convert the API classes of *Table to interfaces URL: https://github.com/apache/flink/pull/8006#discussion_r266766569
########## File path: flink-table/flink-table-api-java/src/main/java/org/apache/flink/table/api/GroupWindowedTable.java ########## @@ -0,0 +1,69 @@ +/* + * 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.flink.table.api; + +import org.apache.flink.annotation.PublicEvolving; +import org.apache.flink.table.expressions.Expression; + +/** + * A table that has been windowed for {@link GroupWindow}s. + */ +@PublicEvolving +public interface GroupWindowedTable { + + /** + * Groups the elements by a mandatory window and one or more optional grouping attributes. + * The window is specified by referring to its alias. + * + * <p>If no additional grouping attribute is specified and if the input is a streaming table, + * the aggregation will be performed by a single task, i.e., with parallelism 1. + * + * <p>Aggregations are performed per group and defined by a subsequent {@code select(...)} + * clause similar to SQL SELECT-GROUP-BY query. + * + * <p>Example: + * + * <pre> + * {code + * tab.window([groupWindow].as("w")).groupBy("w, key").select("key, value.avg") + * } + * </pre> + */ + WindowGroupedTable groupBy(String fields); + + /** + * Groups the elements by a mandatory window and one or more optional grouping attributes. + * The window is specified by referring to its alias. + * + * <p>If no additional grouping attribute is specified and if the input is a streaming table, + * the aggregation will be performed by a single task, i.e., with parallelism 1. + * + * <p>Aggregations are performed per group and defined by a subsequent {@code select(...)} + * clause similar to SQL SELECT-GROUP-BY query. + * + * <p>Example: Review comment: How about we change it to `Scala example:`? This will not work in Java. ---------------------------------------------------------------- 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: [email protected] With regards, Apache Git Services
