org.apache.drill.exec.expr.annotations

Annotation Type FunctionTemplate

@Retention(value=RUNTIME)
 @Target(value=TYPE)
public @interface FunctionTemplate

Field Summary

Fields

Modifier and Type	Fields and Description
static int	OUTPUT_SIZE_ESTIMATE_DEFAULT

Required Element Summary

Required Elements

Modifier and Type	Required Element and Description
FunctionTemplate.FunctionScope	scope

Optional Element Summary

Optional Elements

Modifier and Type	Optional Element and Description
boolean	checkPrecisionRange
FunctionTemplate.FunctionCostCategory	costCategory
String	desc
boolean	isBinaryCommutative
boolean	isInternal Defines if a function is internal and not intended for public use [e.g.
boolean	isNiladic Set Operand type-checking strategy for an operator which takes no operands and need to be invoked without parentheses.
boolean	isRandom
boolean	isVarArg Defines if a function accepts variable arguments count
String	name Name of function (when only one.) Use this annotation element if there is only one name for the function.
String[]	names Names of function (when multiple).
FunctionTemplate.NullHandling	nulls
int	outputSizeEstimate
FunctionTemplate.OutputWidthCalculatorType	outputWidthCalculatorType
FunctionTemplate.ReturnType	returnType

Field Detail

OUTPUT_SIZE_ESTIMATE_DEFAULT

public static final int OUTPUT_SIZE_ESTIMATE_DEFAULT

Element Detail

scope

public abstract FunctionTemplate.FunctionScope scope

name

public abstract String name

Name of function (when only one.) Use this annotation element if there is only one name for the function. Note: If you use this annotation don't use names().

TODO: Refer to wherever list of possible or at least known names is, to resolve the current issue of spaces vs. underlines in names (e.g., we have both "less_than" and "less than".

Returns:

function name

Default:

""

names

public abstract String[] names

Names of function (when multiple). Use this annotation element if there are multiple names for the function. Note: If you use this annotation don't use name().

TODO: Refer to wherever list of possible or at least known names is, to resolve the current issue of spaces vs. underlines in names (e.g., we have both "less_than" and "less than".

Returns:

list of function names

Default:

{}

returnType

public abstract FunctionTemplate.ReturnType returnType

Default:

org.apache.drill.exec.expr.annotations.FunctionTemplate.ReturnType.DEFAULT

nulls

public abstract FunctionTemplate.NullHandling nulls

Default:

org.apache.drill.exec.expr.annotations.FunctionTemplate.NullHandling.INTERNAL

isBinaryCommutative

public abstract boolean isBinaryCommutative

Default:

false

isRandom

public abstract boolean isRandom

Default:

false

desc

public abstract String desc

Default:

""

costCategory

public abstract FunctionTemplate.FunctionCostCategory costCategory

Default:

org.apache.drill.exec.expr.annotations.FunctionTemplate.FunctionCostCategory.SIMPLE

isNiladic

public abstract boolean isNiladic

Set Operand type-checking strategy for an operator which takes no operands and need to be invoked without parentheses. E.g.: session_id is a niladic function.

Niladic functions override columns that have names same as any niladic function. Such columns cannot be queried without the table qualification. Value of the niladic function is returned when table qualification is not used.

For e.g. in the case of session_id:
select session_id from table -> returns the value of niladic function session_id
select t1.session_id from table t1 -> returns session_id column value from table

Default:

false

checkPrecisionRange

public abstract boolean checkPrecisionRange

Default:

false

isInternal

public abstract boolean isInternal

Defines if a function is internal and not intended for public use [e.g. castEmptyStringNullableVarBinaryToNullableVarDecimal(..) ]

Default:

false

isVarArg

public abstract boolean isVarArg

Defines if a function accepts variable arguments count

Default:

false

outputWidthCalculatorType

public abstract FunctionTemplate.OutputWidthCalculatorType outputWidthCalculatorType

Default:

org.apache.drill.exec.expr.annotations.FunctionTemplate.OutputWidthCalculatorType.DEFAULT

outputSizeEstimate

public abstract int outputSizeEstimate

Default:

-1