com.amazonaws.services.dynamodbv2.datamodeling

Annotation Type DynamoDBAutoGenerated

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

Annotation to mark a property as using a custom auto-generator. May be annotated on a user-defined annotation to pass additional information to the DynamoDBAutoGenerator. A minimal example using getter annotations,

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

     @DynamoDBHashKey
     @CustomGeneratedKey(prefix="test-") //<- user-defined annotation
     public String getKey() { return this.key; }
     public void setKey(String key) { this.key = key; }

     public String getValue() { return this.value; }
     public void setValue(String value) { this.value = value; }
 }
 

And user-defined annotation,

 @DynamoDBAutoGenerated(generator=CustomGeneratedKey.Generator.class)
 @Retention(RetentionPolicy.RUNTIME)
 @Target({ElementType.METHOD})
 public @interface CustomGeneratedKey {
     String prefix() default "";

     public static final class Generator implements DynamoDBAutoGenerator<String> {
         private final String prefix;
         public Generator(final CustomGeneratedKey annotation) {
             this.prefix = annotation.prefix();
         }
         public Generator() {
             this.prefix = "";
         }
         @Override
         public DynamoDBAutoGenerateStrategy getGenerateStrategy() {
             return DynamoDBAutoGenerateStrategy.CREATE;
         }
         @Override
         public final T generate(final T currentValue) {
             return prefix + UUID.randomUUID.toString();
         }
     }
 }
 

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

 @DynamoDBHashKey
 @DynamoDBAutoGenerated(generator=CustomGeneratedKey.Generator.class)
 public String getKey() { return this.key; }
 

See Also:

DynamoDBAutoGeneratedDefault, DynamoDBAutoGeneratedKey, DynamoDBAutoGeneratedTimestamp, DynamoDBAutoGenerator, DynamoDBVersionAttribute

Required Element Summary

Required Elements

Modifier and Type	Required Element and Description
Class<? extends DynamoDBAutoGenerator>	generator The auto-generator class for this property.

Element Detail

generator

public abstract Class<? extends DynamoDBAutoGenerator> generator

The auto-generator class for this property.