/**
* 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.resolver;
import java.util.List;
import org.apache.drill.common.expression.FunctionCall;
import org.apache.drill.exec.expr.fn.DrillFuncHolder;
/**
* An implementing class of FunctionResolver provide their own algorithm to choose a DrillFuncHolder from a given list of
* candidates, with respect to a given FunctionCall
*/
public interface FunctionResolver {
/**
* Creates a placeholder SqlFunction for an invocation of a function with a
* possibly qualified name. This name must be resolved into either a builtin
* function or a user-defined function.
*
* @param methods a list of candidates of DrillFuncHolder to be chosen from
* @param call a given function call whose DrillFuncHolder is to be determined via this method
* @return DrillFuncHolder the chosen DrillFuncHolder
*/
DrillFuncHolder getBestMatch(List<DrillFuncHolder> methods, FunctionCall call);
}