org.mule.runtime.api.el

Interface ExpressionFunction

public interface ExpressionFunction

Representation of a function to be used by an ExpressionLanguage. Allows to define the parameter list expected and the return type so that validations can be applied before and after execution by the ExpressionLanguage. Thus, it is not necessary for implementations to validate the input.

Since:

1.0

Method Summary

Modifier and Type	Method and Description
Object	call(Object[] parameters, BindingContext context) Function logic to be executed.
List<FunctionParameter>	parameters() Indicates the parameters this function takes.
Optional<DataType>	returnType() Indicates the return type, if any.

Method Detail

call

Object call(Object[] parameters,
            BindingContext context)

Function logic to be executed.

Parameters:

parameters - array of parameters that should match the indicated ones in parameters().

context - the current BindingContext at the time of execution.

Returns:

the function outcome that should match the one indicated in returnType().

returnType

Optional<DataType> returnType()

Indicates the return type, if any. Notice that it should match the returned Object in call(Object[], BindingContext) and be empty if null is returned. This will be validated before execution.

Returns:

an Optional DataType

parameters

List<FunctionParameter> parameters()

Indicates the parameters this function takes. Notice that the order and amount should match the expected ones in call(Object[], BindingContext). This will be validated before execution.

Returns:

a List of FunctionParameters