com.amazonaws.services.dynamodbv2.datamodeling

Annotation Type DynamoDBTypeConverted

@Retention(value=RUNTIME)
 @Target(value={TYPE,FIELD,METHOD,ANNOTATION_TYPE})
public @interface DynamoDBTypeConverted

Annotation to mark a property as using a custom type-converter.

May be annotated on a user-defined annotation to pass additional properties to the DynamoDBTypeConverter.

 @CurrencyFormat(separator=" ") //<- user-defined annotation
 public Currency getCurrency()
 

Where,

 public class Currency {
     private Double amount;
     private String unit;

     public Double getAmount() { return amount; }
     public void setAmount(Double amount) { this.amount = amount; }

     public String getUnit() { return unit; }
     public void setUnit(String unit) { this.unit = unit; }
 }
 

And user-defined annotation,

 @Target({ElementType.METHOD})
 @Retention(RetentionPolicy.RUNTIME)
 @DynamoDBTypeConverted(converter=CurrencyFormat.Converter.class)
 public @interface CurrencyFormat {

     String separator() default " ";

     public static class Converter implements DynamoDBTypeConverter<String,Currency> {
         private final String separator;
         public Converter(final Class<Currency> targetType, final CurrencyFormat annotation) {
             this.separator = annotation.separator();
         }
         public Converter() {
             this.separator = "|";
         }
         @Override
         public String convert(final Currency o) {
             return String.valueOf(o.getAmount()) + separator + o.getUnit();
         }
         @Override
         public Currency unconvert(final String o) {
             final String[] strings = o.split(separator);
             final Currency currency = new Currency();
             currency.setAmount(Double.valueOf(strings[0]));
             currency.setUnit(strings[1]);
             return currency;
         }
     }
 }
 

Alternately, the property/field may be annotated directly (which requires the converter to provide a default constructor or a constructor with only the targetType),

 @DynamoDBTypeConverted(converter=CurrencyFormat.Converter.class)
 public Currency getCurrency() { return currency; }
 

All converters are null-safe, a null value will never be passed to DynamoDBTypeConverter.convert(T) or DynamoDBTypeConverter.unconvert(S).

Precedence for selecting a type-converter first goes to getter annotations, then field, then finally type.

May be used in combination with DynamoDBTyped to specify the attribute type binding.

Compatible with DynamoDBAutoGeneratedTimestamp

May be used as a meta-annotation.

Required Element Summary

Required Elements

Modifier and Type	Required Element and Description
Class<? extends DynamoDBTypeConverter>	converter The class of the converter for this property.

Element Detail

converter

public abstract Class<? extends DynamoDBTypeConverter> converter

The class of the converter for this property.