software.amazon.awssdk.enhanced.dynamodb.mapper

Class BeanTableSchema<T>

java.lang.Object

software.amazon.awssdk.enhanced.dynamodb.mapper.BeanTableSchema<T>

Type Parameters:

T - The type of object that this TableSchema maps to.

All Implemented Interfaces:

TableSchema<T>

public final class BeanTableSchema<T>
extends Object
implements TableSchema<T>

Implementation of TableSchema that builds a table schema based on properties and annotations of a bean class. Example:

 
  @DynamoDbBean
 public class CustomerAccount {
     private String unencryptedBillingKey;

      @DynamoDbPartitionKey
      @DynamoDbSecondarySortKey(indexName = "accounts_by_customer")
     public String accountId;

      @DynamoDbSortKey
      @DynamoDbSecondaryPartitionKey(indexName = "accounts_by_customer")
     public String customerId;

      @DynamoDbAttribute("account_status")
     public CustomerAccountStatus status;

      @DynamoDbFlatten(dynamoDbBeanClass = Customer.class)
     public Customer customer;

     public Instant createdOn;

     // All public fields must be opted out to not participate in mapping
      @DynamoDbIgnore
     public String internalKey;

     public enum CustomerAccountStatus {
         ACTIVE,
         CLOSED
     }
 }
 
  @DynamoDbBean
 public class Customer {
     public String name;

      public List<String> address;
 }
 }
 

Method Summary

Modifier and Type	Method and Description
AttributeValue	attributeValue(T item, String key) Returns a single attribute value from the modelled object.
static <T> BeanTableSchema<T>	create(Class<T> beanClass) Scans a bean class and builds a BeanTableSchema from it that can be used with the DynamoDbEnhancedClient.
Map<String,AttributeValue>	itemToMap(T item, boolean ignoreNulls) Takes a modelled object and converts it into a raw map of AttributeValue that the DynamoDb low-level SDK can work with.
Map<String,AttributeValue>	itemToMap(T item, Collection<String> attributes) Takes a modelled object and extracts a specific set of attributes which are then returned as a map of AttributeValue that the DynamoDb low-level SDK can work with.
EnhancedType<T>	itemType() Returns the EnhancedType that represents the 'Type' of the Java object this table schema object maps to and from.
T	mapToItem(Map<String,AttributeValue> attributeMap) Takes a raw DynamoDb SDK representation of a record in a table and maps it to a Java object.
TableMetadata	tableMetadata() Returns the object that describes the structure of the table being modelled by the mapper.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Methods inherited from interface software.amazon.awssdk.enhanced.dynamodb.TableSchema

builder, fromBean

Method Detail

create

public static <T> BeanTableSchema<T> create(Class<T> beanClass)

Scans a bean class and builds a BeanTableSchema from it that can be used with the DynamoDbEnhancedClient.

Type Parameters:

T - The bean class type.

Parameters:

beanClass - The bean class to build the table schema from.

Returns:

An initialized BeanTableSchema

mapToItem

public T mapToItem(Map<String,AttributeValue> attributeMap)

Takes a raw DynamoDb SDK representation of a record in a table and maps it to a Java object. A new object is created to fulfil this operation.

If attributes are missing from the map, that will not cause an error, however if attributes are found in the map which the mapper does not know how to map, an exception will be thrown.

Specified by:

mapToItem in interface TableSchema<T>

Parameters:

attributeMap - A map of String to AttributeValue that contains all the raw attributes to map.

Returns:

A new instance of a Java object with all the attributes mapped onto it.

itemToMap

public Map<String,AttributeValue> itemToMap(T item,
                                            boolean ignoreNulls)

Takes a modelled object and converts it into a raw map of AttributeValue that the DynamoDb low-level SDK can work with.

Specified by:

itemToMap in interface TableSchema<T>

Parameters:

item - The modelled Java object to convert into a map of attributes.

ignoreNulls - If set to true; any null values in the Java object will not be added to the output map. If set to false; null values in the Java object will be added as AttributeValue of type 'nul' to the output map.

Returns:

A map of String to AttributeValue representing all the modelled attributes in the model object.

itemToMap

public Map<String,AttributeValue> itemToMap(T item,
                                            Collection<String> attributes)

Takes a modelled object and extracts a specific set of attributes which are then returned as a map of AttributeValue that the DynamoDb low-level SDK can work with. This method is typically used to extract just the key attributes of a modelled item and will not ignore nulls on the modelled object.

Specified by:

itemToMap in interface TableSchema<T>

Parameters:

item - The modelled Java object to extract the map of attributes from.

attributes - A collection of attribute names to extract into the output map.

Returns:

A map of String to AttributeValue representing the requested modelled attributes in the model object.

attributeValue

public AttributeValue attributeValue(T item,
                                     String key)

Returns a single attribute value from the modelled object.

Specified by:

attributeValue in interface TableSchema<T>

Parameters:

item - The modelled Java object to extract the attribute from.

key - The attribute name describing which attribute to extract.

Returns:

A single AttributeValue representing the requested modelled attribute in the model object or null if the attribute has not been set with a value in the modelled object.

tableMetadata

public TableMetadata tableMetadata()

Returns the object that describes the structure of the table being modelled by the mapper. This includes information such as the table name, index keys and attribute tags.

Specified by:

tableMetadata in interface TableSchema<T>

Returns:

A TableMetadata object that contains structural information about the table being modelled.

itemType

public EnhancedType<T> itemType()

Description copied from interface: TableSchema

Returns the EnhancedType that represents the 'Type' of the Java object this table schema object maps to and from.

Specified by:

itemType in interface TableSchema<T>

Returns:

The EnhancedType of the modelled item this TableSchema maps to.