| /* |
| * 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.beam.sdk.extensions.sql; |
| |
| import static java.util.stream.Collectors.toList; |
| |
| import java.util.Collection; |
| import java.util.Collections; |
| import java.util.List; |
| import org.apache.beam.sdk.extensions.sql.impl.TableName; |
| import org.apache.beam.vendor.calcite.v1_28_0.org.apache.calcite.sql.SqlAsOperator; |
| import org.apache.beam.vendor.calcite.v1_28_0.org.apache.calcite.sql.SqlCall; |
| import org.apache.beam.vendor.calcite.v1_28_0.org.apache.calcite.sql.SqlIdentifier; |
| import org.apache.beam.vendor.calcite.v1_28_0.org.apache.calcite.sql.SqlJoin; |
| import org.apache.beam.vendor.calcite.v1_28_0.org.apache.calcite.sql.SqlNode; |
| import org.apache.beam.vendor.calcite.v1_28_0.org.apache.calcite.sql.SqlSelect; |
| import org.apache.beam.vendor.calcite.v1_28_0.org.apache.calcite.sql.SqlSetOperator; |
| import org.apache.beam.vendor.guava.v32_1_2_jre.com.google.common.collect.ImmutableList; |
| import org.checkerframework.checker.nullness.qual.Nullable; |
| |
| /** |
| * Helper class to extract table identifiers from the query. |
| * |
| * <p>Supports queries: |
| * |
| * <pre> |
| * ... FROM table... |
| * ... FROM table1, table2 AS x... |
| * ... FROM table1 JOIN (LEFT, INNER, OUTER etc) table2 JOIN table3 ... |
| * ... FROM table1 UNION (INTERSECT etc) SELECT ... |
| * </pre> |
| */ |
| public class TableNameExtractionUtils { |
| |
| public static List<TableName> extractTableNamesFromNode(@Nullable SqlNode node) { |
| if (node instanceof SqlSelect) { |
| return extractTableFromSelect((SqlSelect) node); |
| } |
| |
| if (node instanceof SqlIdentifier) { |
| return extractFromIdentifier((SqlIdentifier) node); |
| } |
| |
| if (node instanceof SqlJoin) { |
| return extractFromJoin((SqlJoin) node); |
| } |
| |
| if (node instanceof SqlCall) { |
| return extractFromCall((SqlCall) node); |
| } |
| |
| return Collections.emptyList(); |
| } |
| |
| private static List<TableName> extractTableFromSelect(SqlSelect node) { |
| return extractTableNamesFromNode(node.getFrom()); |
| } |
| |
| private static List<TableName> extractFromCall(SqlCall node) { |
| if (node.getOperator() instanceof SqlAsOperator) { |
| return extractTableNamesFromNode(node.getOperandList().get(0)); |
| } |
| |
| if (node.getOperator() instanceof SqlSetOperator) { |
| return node.getOperandList().stream() |
| .map(TableNameExtractionUtils::extractTableNamesFromNode) |
| .flatMap(Collection::stream) |
| .collect(toList()); |
| } |
| |
| return Collections.emptyList(); |
| } |
| |
| private static List<TableName> extractFromJoin(SqlJoin join) { |
| return ImmutableList.<TableName>builder() |
| .addAll(extractTableNamesFromNode(join.getLeft())) |
| .addAll(extractTableNamesFromNode(join.getRight())) |
| .build(); |
| } |
| |
| private static List<TableName> extractFromIdentifier(SqlIdentifier identifier) { |
| return ImmutableList.of(TableName.create(identifier.names)); |
| } |
| } |