Package jakarta.validation.valueextraction

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 ?>> {

     @Override
     public void extractValues(List<?> originalValue, ValueReceiver receiver) {
         for ( int i = 0; i < originalValue.size(); i++ ) {
             receiver.indexedValue( "<list element>", i, originalValue.get( i ) );
         }
     }
 }
Since:
2.0
Author:
Gunnar Morling, Guillaume Smet
See Also:

  • Nested Class Summary

    Nested Classes
    Modifier and Type
    Interface
    Description
    static interface 
    ValueExtractor.ValueReceiver
    Provides a set of methods receiving value extracted by the ValueExtractor.

  • Method Summary

    Modifier and Type
    Method
    Description
    void
    extractValues(T originalValue, ValueExtractor.ValueReceiver receiver)
    Extracts the values to validate from the original object.

  • Method Details

    • extractValues

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