| /* |
| * 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.sql.parser.node; |
| |
| import org.apache.calcite.sql.parser.SqlParserPos; |
| |
| import java.util.List; |
| |
| /** |
| * A SqlTreeNode is a node of SQL relation tree. |
| */ |
| public interface SqlTreeNode { |
| |
| SqlParserPos getParserPosition(); |
| |
| /** |
| * Returns the type of this node. |
| * |
| * @return a {@link SqlNodeType} value, never null |
| */ |
| SqlNodeType getNodeType(); |
| |
| String explain(); |
| |
| /** |
| * Returns the <code>i</code><sup>th</sup> input node. |
| * |
| * @param i Ordinal of input |
| * @return <code>i</code><sup>th</sup> input |
| */ |
| SqlTreeNode getInput(int i); |
| |
| /** |
| * Returns an array of this node's inputs. If there are no |
| * inputs, returns an empty list, not {@code null}. |
| * |
| * @return Array of this node's inputs |
| */ |
| List<SqlTreeNode> getInputs(); |
| |
| } |