net.markenwerk.commons.interfaces

Interface Translator<From,To>

Type Parameters:

From - The type to translate values from and to.

To - The type to translate values to and from.

All Superinterfaces:

Converter<From,To>

public interface Translator<From,To>
extends Converter<From,To>

A Translator is used to convert (transform, translate, project, evaluate, ...) values from one form into another and back. As such, a Translator is little more than an arbitrary function and its reveres function.It is usually used in a scenario where some sort of data provider wants to offer the possibility to convert values into the desired type before delivery or during the data processing.

Common use cases of a Converter include:

• Translation from a simple type into a more complex type and back.
  

   Converter<String, UUID> uuidTranslator = new Translator<String, UUID> () {
     Override
     public UUID convert(String uuidString) throws ConverterException {
       try{
         return UUID.fromString(uuidString);
       } catch (IllegalArgumentException e) {
         throw new ConverterException(e);
       }
     }
      
     Override
     public String revert(UUID uuid) {
       return uuid.toString();
     }
   };
   

• Projection of a complex type to one of it's key components and back.
  

   Converter<Entity, Integer> idConverter = new Converter<Entity, Integer> () {
     Override
     public Integer convert(Entity entity) throws ConverterException {
       return entity.getId();
     }
     
     Override
     public Entity revert(Integer id) {
       try{
         return EntityDao.getById(id);
       } catch (EntityDaoException e) {
         throw new ConverterException(e);
       }
     }
   };
   

Since:

1.0.0

Author:

Torsten Krause (tk at markenwerk dot net)

See Also:

Converter

Method Summary

Modifier and Type	Method and Description
From	revert(To to) Called to revert a given value.

Methods inherited from interface net.markenwerk.commons.interfaces.Converter

convert

Method Detail

revert

From revert(To to)
     throws ConversionException

Called to revert a given value. This is the reverse function of Converter.convert(Object).

Depending on the use case, if the given value null, the Translator should return null.

It lies in the responsibility of the caller, to handle unwanted null-values by replacing them with a sensible default value or throwing a NullPointerException.

Implementers should catch any exception and wrap them in a ConversionException.

Parameters:

to - The value to be reverted.

Returns:

The reverted value.

Throws:

ConversionException - If the reversion failed.