com.hazelcast.jet.sql.impl.validate.operators.typeinference.CoalesceOperandTypeInference Maven / Gradle / Ivy
/*
* Copyright 2021 Hazelcast Inc.
*
* Licensed under the Hazelcast Community License (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://hazelcast.com/hazelcast-community-license
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.hazelcast.jet.sql.impl.validate.operators.typeinference;
import com.hazelcast.jet.sql.impl.validate.HazelcastCallBinding;
import com.hazelcast.jet.sql.impl.validate.types.HazelcastTypeUtils;
import com.hazelcast.org.apache.calcite.rel.type.RelDataType;
import com.hazelcast.org.apache.calcite.sql.SqlCallBinding;
import com.hazelcast.org.apache.calcite.sql.type.SqlOperandTypeInference;
import com.hazelcast.org.apache.calcite.sql.type.SqlTypeName;
import java.util.ArrayList;
import java.util.List;
import static com.hazelcast.jet.sql.impl.validate.types.HazelcastTypeUtils.createType;
import static com.hazelcast.jet.sql.impl.validate.types.HazelcastTypeUtils.isNullOrUnknown;
import static com.hazelcast.jet.sql.impl.validate.types.HazelcastTypeUtils.precedenceOf;
import static com.hazelcast.jet.sql.impl.validate.types.HazelcastTypeUtils.toHazelcastType;
/**
* A type inference algorithm that infers unknown operands to the type of
* the operand with a known type with highest precedence.
*/
public final class CoalesceOperandTypeInference implements SqlOperandTypeInference {
public static final CoalesceOperandTypeInference INSTANCE = new CoalesceOperandTypeInference();
private CoalesceOperandTypeInference() {
}
@Override
public void inferOperandTypes(SqlCallBinding binding, RelDataType returnType, RelDataType[] operandTypes) {
if (operandTypes.length == 0) {
// will be handled later
return;
}
assert binding.getOperandCount() == operandTypes.length;
boolean hasParameters = HazelcastTypeUtils.hasParameters(binding);
List unknownOperandIndexes = new ArrayList<>();
RelDataType knownType = null;
int knownTypePrecedence = Integer.MIN_VALUE;
for (int i = 0; i < binding.getOperandCount(); i++) {
operandTypes[i] = binding.getOperandType(i);
if (!operandTypes[i].equals(binding.getValidator().getUnknownType())) {
if (hasParameters && toHazelcastType(operandTypes[i]).getTypeFamily().isNumericInteger()) {
// If there are parameters in the operands, widen all the integers to BIGINT so that an expression
// `COALESCE(1, ?)` is resolved to `COALESCE((BIGINT)1, (BIGINT)?)` rather than
// `COALESCE((TINYINT)1, (TINYINT)?)`
operandTypes[i] = createType(binding.getTypeFactory(), SqlTypeName.BIGINT, operandTypes[i].isNullable());
}
int precedence = precedenceOf(operandTypes[i]);
if (knownTypePrecedence < precedence) {
knownType = operandTypes[i];
knownTypePrecedence = precedence;
}
} else {
unknownOperandIndexes.add(i);
}
}
// If we have only UNKNOWN operands or a combination of NULL and UNKNOWN, throw a signature error,
// since we cannot deduce the return type
if (knownType == null || isNullOrUnknown(knownType.getSqlTypeName()) && hasParameters) {
throw new HazelcastCallBinding(binding).newValidationSignatureError();
}
for (Integer index : unknownOperandIndexes) {
operandTypes[index] = knownType;
}
}
}