Update User defined object of the dynamoDb item using UpdateItemRequest

Question

We have a DynamoDB table Test which has an attribute Template. Bellow are the class definitions. I would like to update the Template attribute or some of its attribute based on certain condition. I tried doing the same using UpdateItemRequest but unable to find a way to update the template attribute since everything is converted to either string, number or bytes.

Code for reference.

@DynamoDbBean
public class Test implements NoSQLEntity {
        
private String name;
private Template template;
        
@DynamoDbAttribute("name")
public String getName() {
    return name;
}
        
@DynamoDbAttribute("template")
public Template getTemplate() {
     return template;
}   
}

   @DynamoDbBean
   public class Template {

   private String pk;
   private String name;
   private List<String> demo;

   @DynamoDbAttribute("pk")
   public String getPk() {
        return this.pk;
   }
            
   @DynamoDbAttribute("name")
   public String getName() {
         return name;
   }

   @DynamoDbAttribute("demo")
   public List<String> getdemo() {
       return demo;
   } 

}

Sample update code:

UpdateItemRequest request = UpdateItemRequest.builder()
            .tableName("Test")
            .key(itemKey)
            .updateExpression("SET tmpt = :tmt")
            .expressionAttributeValues(expressionValues)
            .build();

Here I am unable to build the :tmt using the AttributeValue. Can someone please guide me?

smac2020 · Accepted Answer · 2021-02-03 21:31:31Z

1

Here is a Readme from the Eng team that you may find useful:

https://github.com/aws/aws-sdk-java-v2/tree/master/services-custom/dynamodb-enhanced

answered Feb 3, 2021 at 21:31

smac2020

11k4 gold badges27 silver badges46 bronze badges

Sign up to request clarification or add additional context in comments.

2 Comments

Jaspreet Chhabra Over a year ago

I did go through this but still struggling to find a way to update user defined objects

Jaspreet Chhabra Over a year ago

Thanks for the link !! Converter served my purpose

Jaspreet Chhabra · Accepted Answer · 2021-02-04 10:55:34Z

DynamoDb Enhanced provides DefaultAttributeConverterProvider that will identify a converter that can convert the specific Java type into the AttrbuteValue type that can used to update the item.

Smaple Code:

    AttributeValue value = DefaultAttributeConverterProvider.create()
            .converterFor(EnhancedType.documentOf(Template.class, 
             TableSchema.fromBean(Template.class)))
            .transformFrom(template);

Can then put this value in the expressionValues map.

   Map<String, AttributeValue> expressionValues = new HashMap<>();
    expressionValues.put(":tmt", value);

   UpdateItemRequest request = UpdateItemRequest.builder()
        .tableName("Test")
        .key(itemKey)
        .updateExpression("SET tmpt = :tmt")
        .expressionAttributeValues(expressionValues)
        .build();

Collectives™ on Stack Overflow

Update User defined object of the dynamoDb item using UpdateItemRequest

2 Answers 2

2 Comments

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

2 Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Related