| /* |
| * 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.common.expression.fn; |
| |
| import org.apache.drill.common.expression.ExpressionPosition; |
| import org.apache.drill.common.expression.FunctionHolderExpression; |
| import org.apache.drill.common.expression.LogicalExpression; |
| import org.apache.drill.common.types.TypeProtos; |
| |
| import java.util.List; |
| |
| /** |
| * Definition of a function as presented to code generation. |
| * Represents the common denominator between Drill and Hive |
| * functions. |
| */ |
| public interface FuncHolder { |
| |
| boolean isNested(); |
| |
| /** |
| * Return a reference to this function given a function alias and a |
| * list of actual arguments. |
| * |
| * @param name alias used in this specific call |
| * @param args expressions of the actual function arguments |
| * @param pos |
| * @return an expression that holds the function definition (this object), |
| * actual parameters and related information |
| */ |
| FunctionHolderExpression getExpr(String name, List<LogicalExpression> args, ExpressionPosition pos); |
| |
| /** |
| * Number of defined input parameters. |
| */ |
| int getParamCount(); |
| |
| /** |
| * Drill SQL type of an input parameter. |
| */ |
| TypeProtos.MajorType getParamMajorType(int i); |
| |
| /** |
| * Checks that the current function holder stores output value |
| * using field writer instead of vector holder. |
| * |
| * @return true if current function holder uses field writer to store the output value |
| */ |
| boolean isComplexWriterFuncHolder(); |
| } |