com.hazelcast.org.apache.calcite.schema.TableFactory Maven / Gradle / Ivy
/*
* 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 com.hazelcast.org.apache.calcite.schema;
import com.hazelcast.org.apache.calcite.rel.type.RelDataType;
import com.hazelcast.org.checkerframework.checker.nullness.qual.Nullable;
import java.util.Map;
/**
* Factory for {@link Table} objects.
*
* A table factory allows you to include custom tables in a model file.
* For example, here is a model that contains a custom table that generates
* a range of integers.
*
* {
* version: '1.0',
* defaultSchema: 'MATH',
* schemas: [
* {
* name: 'MATH',
* tables: [
* {
* name: 'INTEGERS',
* type: 'custom',
* factory: 'com.acme.IntegerTable',
* operand: {
* start: 3,
* end: 7,
* column: 'N'
* }
* }
* ]
* }
* ]
* }
*
* Given that schema, the query
*
* SELECT * FROM math.integers
*
* returns
*
*
* +---+
* | N |
* +---+
* | 3 |
* | 4 |
* | 5 |
* | 6 |
* +---+
*
*
* A class that implements TableFactory specified in a schema must have a
* public default constructor.
*
* @param Sub-type of table created by this factory
*/
public interface TableFactory {
/** Creates a Table.
*
* @param schema Schema this table belongs to
* @param name Name of this table
* @param operand The "operand" JSON property
* @param rowType Row type. Specified if the "columns" JSON property.
* @return created table
*/
T create(
SchemaPlus schema,
String name,
Map operand,
@Nullable RelDataType rowType);
}
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