Interface ArgumentConverter

All Known Implementing Classes:
AnnotationBasedArgumentConverter, DefaultArgumentConverter, SimpleArgumentConverter, TypedArgumentConverter
@API(status=STABLE, since="5.7") public interface ArgumentConverter
ArgumentConverter is an abstraction that allows an input object to be converted to an instance of a different class.

Such an ArgumentConverter is applied to the method parameter of a @ParameterizedTest or a constructor parameter or @Parameter-annotated field of a @ParameterizedClass with the help of a @ConvertWith annotation.

Implementations must provide a no-args constructor or a single unambiguous constructor to use parameter resolution. They should not make any assumptions regarding when they are instantiated or how often they are called. Since instances may potentially be cached and called from different threads, they should be thread-safe.

Extend SimpleArgumentConverter if your implementation only needs to know the target type and does not need access to the ParameterContext to perform the conversion.

Extend TypedArgumentConverter if your implementation always converts from a given source type into a given target type and does not need access to the ParameterContext to perform the conversion.

Since:
5.0
See Also:

  • Method Summary

    Modifier and Type
    Method
    Description
    @Nullable Object
    convert(@Nullable Object source, ParameterContext context)
    Convert the supplied source object according to the supplied context.
    default @Nullable Object
    convert(@Nullable Object source, FieldContext context)
    Convert the supplied source object according to the supplied context.

  • Method Details

    • convert

      @Nullable Object convert(@Nullable Object source, ParameterContext context) throws ArgumentConversionException
      Convert the supplied source object according to the supplied context.
      Parameters:
      source - the source object to convert; may be null
      context - the parameter context where the converted object will be supplied; never null
      Returns:
      the converted object; may be null but only if the target type is a reference type
      Throws:
      ArgumentConversionException - if an error occurs during the conversion

    • convert

      @API(status=EXPERIMENTAL, since="6.0") default @Nullable Object convert(@Nullable Object source, FieldContext context) throws ArgumentConversionException
      Convert the supplied source object according to the supplied context.
      Parameters:
      source - the source object to convert; may be null
      context - the field context where the converted object will be injected; never null
      Returns:
      the converted object; may be null but only if the target type is a reference type
      Throws:
      ArgumentConversionException - if an error occurs during the conversion
      Since:
      5.13