org.apache.drill.exec.resolver

Interface FunctionResolver

All Known Implementing Classes:

DefaultFunctionResolver, ExactFunctionResolver

public interface FunctionResolver

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

Method Summary

Modifier and Type	Method and Description
DrillFuncHolder	getBestMatch(List<DrillFuncHolder> methods, FunctionCall call) Creates a placeholder SqlFunction for an invocation of a function with a possibly qualified name.

Method Detail

getBestMatch

DrillFuncHolder getBestMatch(List<DrillFuncHolder> methods,
                             FunctionCall call)

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.

Parameters:

methods - a list of candidates of DrillFuncHolder to be chosen from

call - a given function call whose DrillFuncHolder is to be determined via this method

Returns:

DrillFuncHolder the chosen DrillFuncHolder