com.hazelcast.org.apache.calcite.sql.SqlNullTreatmentOperator 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.sql;
import com.hazelcast.org.apache.calcite.sql.parser.SqlParserPos;
import com.hazelcast.org.apache.calcite.sql.type.OperandTypes;
import com.hazelcast.org.apache.calcite.sql.type.ReturnTypes;
import com.hazelcast.org.apache.calcite.sql.validate.SqlValidator;
import com.hazelcast.org.apache.calcite.sql.validate.SqlValidatorScope;
import com.hazelcast.org.apache.calcite.util.ImmutableNullableList;
import com.hazelcast.com.google.common.base.Preconditions;
import com.hazelcast.org.checkerframework.checker.nullness.qual.Nullable;
import static com.hazelcast.org.apache.calcite.util.Static.RESOURCE;
/**
* An operator that decides how to handle null input
* ({@code RESPECT NULLS} and {@code IGNORE NULLS}).
*
* Currently, only the windowed aggregate functions {@code FIRST_VALUE},
* {@code LAST_VALUE}, {@code LEAD} and {@code LAG} support it.
*
* @see SqlAggFunction#allowsNullTreatment()
*/
public class SqlNullTreatmentOperator extends SqlSpecialOperator {
public SqlNullTreatmentOperator(SqlKind kind) {
super(kind.sql, kind, 20, true, ReturnTypes.ARG0, null, OperandTypes.ANY);
Preconditions.checkArgument(kind == SqlKind.RESPECT_NULLS
|| kind == SqlKind.IGNORE_NULLS);
}
@Override public SqlCall createCall(@Nullable SqlLiteral functionQualifier,
SqlParserPos pos, @Nullable SqlNode... operands) {
// As super.createCall, but don't union the positions
return new SqlBasicCall(this, ImmutableNullableList.copyOf(operands), pos,
functionQualifier);
}
@Override public void unparse(SqlWriter writer, SqlCall call, int leftPrec,
int rightPrec) {
assert call.operandCount() == 1;
call.operand(0).unparse(writer, getLeftPrec(), getRightPrec());
writer.keyword(getName());
}
@Override public void validateCall(
SqlCall call,
SqlValidator validator,
SqlValidatorScope scope,
SqlValidatorScope operandScope) {
assert call.getOperator() == this;
assert call.operandCount() == 1;
SqlCall aggCall = call.operand(0);
if (!aggCall.getOperator().isAggregator()
|| !((SqlAggFunction) aggCall.getOperator()).allowsNullTreatment()) {
throw validator.newValidationError(aggCall,
RESOURCE.disallowsNullTreatment(aggCall.getOperator().getName()));
}
}
}