Interface ValueExtractor<T>

  • Type Parameters:
    T - the container type handled by a specific implementation

    public interface ValueExtractor<T>
    Defines the logic used to extract the values from a container object of type T.

    A value extractor for a generic type such as Optional, List or Map is tied to one specific type parameter of T. The ExtractedValue annotation is used to mark that type parameter. A value extractor for a non-generic type such as OptionalInt needs to declare the type of the wrapped element(s) using ExtractedValue.type().

    The extracted values are passed to the corresponding method of the ValueExtractor.ValueReceiver.

    A typical value extractor implementation for List may look like this:

     public class ListValueExtractor implements
             ValueExtractor<List<@ExtractedValue ?>> {
         public void extractValues(List<?> originalValue, ValueReceiver receiver) {
             for ( int i = 0; i < originalValue.size(); i++ ) {
                 receiver.indexedValue( "<list element>", i, originalValue.get( i ) );
    See Also:
    ExtractedValue, UnwrapByDefault
    • Method Detail

      • extractValues

        void extractValues​(T originalValue,
                           ValueExtractor.ValueReceiver receiver)
        Extracts the values to validate from the original object.
        originalValue - the original value from which to extract the values, never null
        receiver - the corresponding ValueReceiver