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 information to the DynamoDBTypeConverter. A minimal example using getter annotations,

 @DynamoDBTable(tableName="TestTable")
 public class TestClass {
     private String key;
     private Currency currency;

     @DynamoDBHashKey
     public String getKey() { return key; }
     public void setKey(String key) { this.key = key; }

     @CurrencyFormat(separator=" ") //<- user-defined annotation
     public Currency getCurrency() { return currency; }
     public void setCurrency(Currency currency) { this.currency = currency; }
 }
 

With the complex type to convert:,

 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,

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

     public static final class Converter implements DynamoDBTypeConverter<String,Currency> {
         private final String separator;
         public Converter(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;
         }
     }
 }
 

Alternatively, the property/field may be annotated directly (which requires the converter to provide a default constructor),

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

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

See Also:

DynamoDBDelimited, DynamoDBTypeConvertedEnum, DynamoDBTypeConvertedJson, DynamoDBTypeConvertedTimestamp, DynamoDBTypeConverter

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.