net.markenwerk.commons.interfaces

Interface Converter<From,To>

Type Parameters:

From - The type to convert values from.

To - The type to convert values to.

All Known Subinterfaces:

Translator<From,To>

public interface Converter<From,To>

A Converter is used to convert (transform, translate, project, evaluate, ...) values from one form into another. As such, a Converter is little more than an arbitrary 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:

• Conversion from a simple type into a more complex type.
  

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

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

   Converter<Entity, Integer> idConverter = new Converter<Entity, Integer> () {
     Override
     public Integer convert(Entity entity) throws ConverterException {
       return entity.getId();
     }
   };
   

Since:

1.0.0

Author:

Torsten Krause (tk at markenwerk dot net)

See Also:

Translator

Method Summary

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

Method Detail

convert

To convert(From from)
    throws ConversionException

Called to convert a given value.

Depending on the use case, if the given value null, the Converter 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:

from - The value to be converted.

Returns:

The converted value.

Throws:

ConversionException - If the conversion failed.