SpecializedFunction.ExpressionEvaluator (Flink : 2.0-SNAPSHOT API)

All Superinterfaces:

Serializable

All Known Implementing Classes:

DefaultExpressionEvaluator

Enclosing interface:

SpecializedFunction
```
@PublicEvolving
public static interface SpecializedFunction.ExpressionEvaluator
extends Serializable
```
Serializable factory that can be passed into a UserDefinedFunction for evaluating previously defined expression during runtime.

See Also:

SpecializedFunction.ExpressionEvaluatorFactory.createEvaluator(Expression, DataType, DataTypes.Field...), SpecializedFunction.ExpressionEvaluatorFactory.createEvaluator(BuiltInFunctionDefinition, DataType, DataType...)

Method Summary

All Methods Instance Methods Abstract Methods Default Methods
Modifier and Type	Method	Description
`default void`	`close()`	Closes the runtime implementation for expression evaluation.
`MethodHandle`	`open(FunctionContext context)`	Creates and initializes runtime implementation for expression evaluation.

- Method Detail
  - open
```
MethodHandle open(FunctionContext context)
```
    Creates and initializes runtime implementation for expression evaluation. The returned MethodHandle should be stored in a transient variable and can be invoked via MethodHandle.invokeExact(Object...) using the conversion classes previously defined via the passed DataTypes.
    This method should be called in UserDefinedFunction.open(FunctionContext).
  - close
```
default void close()
```
    Closes the runtime implementation for expression evaluation. It performs clean up work.
    This method should be called in UserDefinedFunction.close().