javax.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:

ExtractedValue, UnwrapByDefault

Nested Class Summary

Nested Classes

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

Method Summary

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

Method Detail

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