| /* |
| * 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.calcite.sql2rel; |
| |
| import org.apache.calcite.rex.RexNode; |
| import org.apache.calcite.sql.SqlCall; |
| |
| /** |
| * SubqueryConverter provides the interface for classes that convert subqueries |
| * into equivalent expressions. |
| */ |
| public interface SubqueryConverter { |
| //~ Methods ---------------------------------------------------------------- |
| |
| /** |
| * @return true if the subquery can be converted |
| */ |
| boolean canConvertSubquery(); |
| |
| /** |
| * Converts the subquery to an equivalent expression. |
| * |
| * @param subquery the SqlNode tree corresponding to a subquery |
| * @param parentConverter sqlToRelConverter of the parent query |
| * @param isExists whether the subquery is part of an EXISTS expression |
| * @param isExplain whether the subquery is part of an EXPLAIN PLAN |
| * statement |
| * @return the equivalent expression or null if the subquery couldn't be |
| * converted |
| */ |
| RexNode convertSubquery( |
| SqlCall subquery, |
| SqlToRelConverter parentConverter, |
| boolean isExists, |
| boolean isExplain); |
| } |
| |
| // End SubqueryConverter.java |