dawidwys commented on a change in pull request #8050: [FLINK-11067][table] Convert TableEnvironments to interfaces URL: https://github.com/apache/flink/pull/8050#discussion_r276212755
########## File path: flink-table/flink-table-api-java-bridge/src/main/java/org/apache/flink/table/api/java/BatchTableEnvironment.java ########## @@ -0,0 +1,289 @@ +/* + * 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.java; + +import org.apache.flink.annotation.PublicEvolving; +import org.apache.flink.api.common.typeinfo.TypeInformation; +import org.apache.flink.api.java.DataSet; +import org.apache.flink.api.java.ExecutionEnvironment; +import org.apache.flink.table.api.BatchQueryConfig; +import org.apache.flink.table.api.Table; +import org.apache.flink.table.api.TableConfig; +import org.apache.flink.table.api.TableEnvironment; +import org.apache.flink.table.api.TableException; +import org.apache.flink.table.descriptors.BatchTableDescriptor; +import org.apache.flink.table.descriptors.ConnectorDescriptor; +import org.apache.flink.table.functions.AggregateFunction; +import org.apache.flink.table.functions.TableFunction; + +import java.lang.reflect.Constructor; + +/** + * The {@link TableEnvironment} for a Java batch {@link ExecutionEnvironment} that works + * with {@link DataSet}s. + * + * <p>A TableEnvironment can be used to: + * <ul> + * <li>convert a {@link DataSet} to a {@link Table}</li> + * <li>register a {@link DataSet} in the {@link TableEnvironment}'s catalog</li> + * <li>register a {@link Table} in the {@link TableEnvironment}'s catalog</li> + * <li>scan a registered table to obtain a {@link Table}</li> + * <li>specify a SQL query on registered tables to obtain a {@link Table}</li> + * <li>convert a {@link Table} into a {@link DataSet}</li> + * <li>explain the AST and execution plan of a {@link Table}</li> + * </ul> + */ +@PublicEvolving +public interface BatchTableEnvironment extends TableEnvironment { + + /** + * Registers a {@link TableFunction} under a unique name in the TableEnvironment's catalog. + * Registered functions can be referenced in Table API and SQL queries. + * + * @param name The name under which the function is registered. + * @param tableFunction The TableFunction to register. + * @param <T> The type of the output row. + */ + <T> void registerFunction(String name, TableFunction<T> tableFunction); + + /** + * Registers an {@link AggregateFunction} under a unique name in the TableEnvironment's catalog. + * Registered functions can be referenced in Table API and SQL queries. + * + * @param name The name under which the function is registered. + * @param aggregateFunction The AggregateFunction to register. + * @param <T> The type of the output value. + * @param <ACC> The type of aggregate accumulator. + */ + <T, ACC> void registerFunction(String name, AggregateFunction<T, ACC> aggregateFunction); + + /** + * Converts the given {@link DataSet} into a {@link Table}. + * + * <p>The field names of the {@link Table} are automatically derived from the type of the + * {@link DataSet}. + * + * @param dataSet The {@link DataSet} to be converted. + * @tparam T The type of the {@link DataSet}. + * @return The converted {@link Table}. + */ + <T> Table fromDataSet(DataSet<T> dataSet); + + /** + * Converts the given {@link DataSet} into a {@link Table} with specified field names. + * + * Example: + * + * {{{ + * DataSet<Tuple2<String, Long>> set = ... + * Table tab = tableEnv.fromDataSet(set, "a, b"); + * }}} + * + * @param dataSet The {@link DataSet} to be converted. + * @param fields The field names of the resulting {@link Table}. + * @tparam T The type of the {@link DataSet}. + * @return The converted {@link Table}. + */ + <T> Table fromDataSet(DataSet<T> dataSet, String fields); + + /** + * Registers the given {@link DataSet} as table in the + * {@link TableEnvironment}'s catalog. + * Registered tables can be referenced in SQL queries. + * + * The field names of the {@link Table} are automatically derived from the type of the{@link DataSet}. + * + * @param name The name under which the {@link DataSet} is registered in the catalog. + * @param dataSet The {@link DataSet} to register. + * @tparam T The type of the {@link DataSet} to register. + */ + <T> void registerDataSet(String name, DataSet<T> dataSet); + + /** + * Registers the given {@link DataSet} as table with specified field names in the + * {@link TableEnvironment}'s catalog. + * Registered tables can be referenced in SQL queries. + * + * Example: + * + * {{{ Review comment: Convert to javadoc ---------------------------------------------------------------- This is an automated message from the Apache Git Service. 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