/*
* 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 org.apache.drill.exec.expr.fn;
import org.apache.drill.common.expression.LogicalExpression;
import org.apache.drill.common.types.TypeProtos;
import org.apache.drill.exec.expr.annotations.FunctionTemplate;
import java.util.List;
public class FunctionUtils {
/**
* Calculates return type data mode based on give logical expressions.
* If null handling strategy is internal, returns return value data mode.
* If null handling strategy is null if null and at least one of the input types are nullable,
* return nullable data mode.
*
* @param logicalExpressions logical expressions
* @param attributes function attributes
* @return data mode
*/
public static TypeProtos.DataMode getReturnTypeDataMode(final List<LogicalExpression> logicalExpressions, FunctionAttributes attributes) {
if (attributes.getNullHandling() == FunctionTemplate.NullHandling.NULL_IF_NULL) {
for (final LogicalExpression logicalExpression : logicalExpressions) {
if (logicalExpression.getMajorType().getMode() == TypeProtos.DataMode.OPTIONAL) {
return TypeProtos.DataMode.OPTIONAL;
}
}
}
return attributes.getReturnValue().getType().getMode();
}
}