org.apache.flink.table.functions.TemporalTableFunctionImpl Maven / Gradle / Ivy
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/*
* 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
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* 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.functions;
import org.apache.flink.annotation.Internal;
import org.apache.flink.api.java.typeutils.RowTypeInfo;
import org.apache.flink.table.expressions.Expression;
import org.apache.flink.table.operations.QueryOperation;
import java.sql.Timestamp;
/**
* Class representing temporal table function over some history table.
* It takes one single argument, the {@code timeAttribute}, for which it returns matching version of
* the {@code underlyingHistoryTable}, from which this {@link TemporalTableFunction} was created.
*
* This function shouldn't be evaluated. Instead calls to it should be rewritten by the optimiser
* into other operators (like Temporal Table Join).
*/
@Internal
public final class TemporalTableFunctionImpl extends TemporalTableFunction {
private final transient QueryOperation underlyingHistoryTable;
private final transient Expression timeAttribute;
private final transient Expression primaryKey;
private final RowTypeInfo resultType;
private TemporalTableFunctionImpl(
QueryOperation underlyingHistoryTable,
Expression timeAttribute,
Expression primaryKey,
RowTypeInfo resultType) {
this.underlyingHistoryTable = underlyingHistoryTable;
this.timeAttribute = timeAttribute;
this.primaryKey = primaryKey;
this.resultType = resultType;
}
public void eval(Timestamp row) {
throw new IllegalStateException("This should never be called");
}
public Expression getTimeAttribute() {
return timeAttribute;
}
public Expression getPrimaryKey() {
return primaryKey;
}
@Override
public RowTypeInfo getResultType() {
return resultType;
}
public QueryOperation getUnderlyingHistoryTable() {
if (underlyingHistoryTable == null) {
throw new IllegalStateException("Accessing table field after planing/serialization");
}
return underlyingHistoryTable;
}
public static TemporalTableFunction create(
QueryOperation operationTree,
Expression timeAttribute,
Expression primaryKey) {
return new TemporalTableFunctionImpl(
operationTree,
timeAttribute,
primaryKey,
new RowTypeInfo(
operationTree.getTableSchema().getFieldTypes(),
operationTree.getTableSchema().getFieldNames()));
}
}