Annotation Type ProcedureHint
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@PublicEvolving @Retention(RUNTIME) @Target({TYPE,METHOD}) @Repeatable(ProcedureHints.class) public @interface ProcedureHint
A hint that influences the reflection-based extraction of arguments and output for constructing theTypeInference
logic of aProcedure
.One or more annotations can be declared on top of a
Procedure
class or individually for eachcall()
method for overloading function signatures. All hint parameters are optional. If a parameter is not defined, the default reflection-based extraction is used. Hint parameters defined on top of aProcedure
class are inherited by allcall()
methods. TheDataTypeHint
for the output data type should always hint the component type of the array returned byProcedure
.The following examples show how to explicitly specify procedure signatures as a whole or in part and let the default extraction do the rest:
{@code // accepts (INT, STRING) and returns BOOLEAN, // the arguments have names and are optional
- See Also:
DataTypeHint
,ArgumentHint
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Optional Element Summary
Optional Elements Modifier and Type Optional Element Description ArgumentHint[]
argument
Deprecated.Usearguments()
instead.String[]
argumentNames
Deprecated.Usearguments()
instead.ArgumentHint[]
arguments
Explicitly lists the arguments that a procedure takes as input.DataTypeHint[]
input
Explicitly lists the argument types that a procedure takes as input.boolean
isVarArgs
Defines that the last argument type defined ininput()
should be treated as a variable-length argument.DataTypeHint
output
Explicitly defines the result type that a procedure uses as output.
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Element Detail
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input
DataTypeHint[] input
Explicitly lists the argument types that a procedure takes as input.By default, explicit input types are undefined and the reflection-based extraction is used.
Note: Specifying the input arguments manually disables the entire reflection-based extraction around arguments. This means that also
isVarArgs()
needs to be specified manually if required.Use
arguments()
for more control about argument names and argument kinds.- Default:
- {@org.apache.flink.table.annotation.DataTypeHint}
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isVarArgs
boolean isVarArgs
Defines that the last argument type defined ininput()
should be treated as a variable-length argument.By default, if
input()
is defined, the last argument type is not a var-arg. Ifinput()
is not defined, the reflection-based extraction is used to decide about the var-arg flag, thus, this parameter is ignored.- Default:
- false
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arguments
ArgumentHint[] arguments
Explicitly lists the arguments that a procedure takes as input. Including their names, data types, kinds, and whether they are optional.It is recommended to use this parameter instead of
input()
. Using bothinput()
and this parameter is not allowed. Specifying the list of arguments manually disables the entire reflection-based extraction around arguments.- Default:
- {}
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output
DataTypeHint output
Explicitly defines the result type that a procedure uses as output.By default, an explicit output type is undefined and the reflection-based extraction is used.
- Default:
- @org.apache.flink.table.annotation.DataTypeHint
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argumentNames
@Deprecated String[] argumentNames
Deprecated.Usearguments()
instead.Explicitly lists the argument names that a procedure takes as input.By default, if
input()
is defined, explicit argument names are undefined and this parameter can be used to provide argument names. Ifinput()
is not defined, the reflection-based extraction is used, thus, this parameter is ignored.- Default:
- {""}
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argument
@Deprecated ArgumentHint[] argument
Deprecated.Usearguments()
instead.Explicitly lists the arguments that a procedure takes as input. Including their names, data types, kinds, and whether they are optional.It is recommended to use this parameter instead of
input()
. Specifying the list of arguments manually disables the entire reflection-based extraction around arguments.- Default:
- {}
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