com.hazelcast.org.apache.calcite.sql.fun.SqlLeadLagAggFunction 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 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.
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package com.hazelcast.org.apache.calcite.sql.fun;
import com.hazelcast.org.apache.calcite.rel.type.RelDataType;
import com.hazelcast.org.apache.calcite.sql.SqlAggFunction;
import com.hazelcast.org.apache.calcite.sql.SqlFunctionCategory;
import com.hazelcast.org.apache.calcite.sql.SqlKind;
import com.hazelcast.org.apache.calcite.sql.SqlOperatorBinding;
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.type.SameOperandTypeChecker;
import com.hazelcast.org.apache.calcite.sql.type.SqlReturnTypeInference;
import com.hazelcast.org.apache.calcite.sql.type.SqlSingleOperandTypeChecker;
import com.hazelcast.org.apache.calcite.sql.type.SqlTypeFamily;
import com.hazelcast.org.apache.calcite.sql.type.SqlTypeTransform;
import com.hazelcast.org.apache.calcite.sql.type.SqlTypeTransforms;
import com.hazelcast.org.apache.calcite.util.Optionality;
import com.hazelcast.com.google.common.base.Preconditions;
import com.hazelcast.com.google.common.collect.ImmutableList;
import java.util.List;
/**
* LEAD
and LAG
aggregate functions
* return the value of given expression evaluated at given offset.
*/
public class SqlLeadLagAggFunction extends SqlAggFunction {
private static final SqlSingleOperandTypeChecker OPERAND_TYPES =
OperandTypes.or(
OperandTypes.ANY,
OperandTypes.family(SqlTypeFamily.ANY, SqlTypeFamily.NUMERIC),
OperandTypes.and(
OperandTypes.family(SqlTypeFamily.ANY, SqlTypeFamily.NUMERIC,
SqlTypeFamily.ANY),
// Arguments 1 and 3 must have same type
new SameOperandTypeChecker(3) {
@Override protected List
getOperandList(int operandCount) {
return ImmutableList.of(0, 2);
}
}));
private static final SqlReturnTypeInference RETURN_TYPE =
ReturnTypes.ARG0.andThen(SqlLeadLagAggFunction::transformType);
public SqlLeadLagAggFunction(SqlKind kind) {
super(kind.name(),
null,
kind,
RETURN_TYPE,
null,
OPERAND_TYPES,
SqlFunctionCategory.NUMERIC,
false,
true,
Optionality.FORBIDDEN);
Preconditions.checkArgument(kind == SqlKind.LEAD
|| kind == SqlKind.LAG);
}
@Deprecated // to be removed before 2.0
public SqlLeadLagAggFunction(boolean isLead) {
this(isLead ? SqlKind.LEAD : SqlKind.LAG);
}
// Result is NOT NULL if NOT NULL default value is provided
private static RelDataType transformType(SqlOperatorBinding binding,
RelDataType type) {
SqlTypeTransform transform =
binding.getOperandCount() < 3 || binding.getOperandType(2).isNullable()
? SqlTypeTransforms.FORCE_NULLABLE
: SqlTypeTransforms.TO_NOT_NULLABLE;
return transform.transformType(binding, type);
}
@Override public boolean allowsFraming() {
return false;
}
@Override public boolean allowsNullTreatment() {
return true;
}
}
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