MetaTableSchema (AWS Java SDK :: DynamoDB :: Enhanced Client 2.20.141 API)

java.lang.Object
- software.amazon.awssdk.enhanced.dynamodb.internal.mapper.MetaTableSchema<T>

All Implemented Interfaces:

TableSchema<T>
```
public class MetaTableSchema<T>
extends Object
implements TableSchema<T>
```
An implementation of TableSchema that can be instantiated as an uninitialized reference and then lazily initialized later with a concrete TableSchema at which point it will behave as the real object.
This allows an immutable TableSchema to be declared and used in a self-referential recursive way within its builder/definition path. Any attempt to use the MetaTableSchema as a concrete TableSchema before calling initialize(TableSchema) will cause an exception to be thrown.

Method Summary

All Methods Static Methods Instance Methods Concrete Methods
Modifier and Type	Method and Description
`List<String>`	`attributeNames()` Returns a complete list of attribute names that are mapped by this `TableSchema`
`AttributeValue`	`attributeValue(T item, String attributeName)` Returns a single attribute value from the modelled object.
`TableSchema<T>`	`concreteTableSchema()`
`AttributeConverter<T>`	`converterForAttribute(Object key)` `AttributeConverter` that is applied to the given key.
`static <T> MetaTableSchema<T>`	`create(Class<T> itemClass)`
`void`	`initialize(TableSchema<T> realTableSchema)`
`boolean`	`isAbstract()` A boolean value that represents whether this `TableSchema` is abstract which means that it cannot be used to directly create records as it is lacking required structural elements to map to a table, such as a primary key, but can be referred to and embedded by other schemata.
`boolean`	`isInitialized()`
`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, builder, builder, builder, documentSchemaBuilder, fromBean, fromClass, fromImmutableClass, mapToItem

- Method Detail
  - create
```
public static <T> MetaTableSchema<T> create(Class<T> itemClass)
```
  - mapToItem
```
public T mapToItem(Map<String,AttributeValue> attributeMap)
```
    Description copied from interface: TableSchema
    
    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.
    If all attribute values in the attributeMap are null, null will be returned. Use TableSchema.mapToItem(Map, boolean) instead if you need to preserve empty object.
    API Implementors Note:
    TableSchema.mapToItem(Map, boolean) must be implemented if preserveEmptyObject behavior is desired.
    
    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.
    
    See Also:
    
    TableSchema.mapToItem(Map, boolean)
  - itemToMap
```
public Map<String,AttributeValue> itemToMap(T item,
                                            boolean ignoreNulls)
```
    Description copied from interface: TableSchema
    
    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)
```
    Description copied from interface: TableSchema
    
    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 attributeName)
```
    Description copied from interface: TableSchema
    
    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.
    
    attributeName - 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()
```
    Description copied from interface: TableSchema
    
    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.
  - attributeNames
```
public List<String> attributeNames()
```
    Description copied from interface: TableSchema
    
    Returns a complete list of attribute names that are mapped by this TableSchema
    
    Specified by:
    
    attributeNames in interface TableSchema<T>
  - isAbstract
```
public boolean isAbstract()
```
    Description copied from interface: TableSchema
    
    A boolean value that represents whether this TableSchema is abstract which means that it cannot be used to directly create records as it is lacking required structural elements to map to a table, such as a primary key, but can be referred to and embedded by other schemata.
    
    Specified by:
    
    isAbstract in interface TableSchema<T>
    
    Returns:
    
    true if it is abstract, and therefore cannot be used directly to create records but can be referred to by other schemata, and false if it is concrete and may be used to map records directly.
  - converterForAttribute
```
public AttributeConverter<T> converterForAttribute(Object key)
```
    Description copied from interface: TableSchema
    
    AttributeConverter that is applied to the given key.
    
    Specified by:
    
    converterForAttribute in interface TableSchema<T>
    
    Parameters:
    
    key - Attribute of the modelled item.
    
    Returns:
    
    AttributeConverter defined for the given attribute key.
  - initialize
```
public void initialize(TableSchema<T> realTableSchema)
```
  - concreteTableSchema
```
public TableSchema<T> concreteTableSchema()
```
  - isInitialized
```
public boolean isInitialized()
```

Class MetaTableSchema<T>

Method Summary

Methods inherited from class java.lang.Object

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

Method Detail

create

mapToItem

itemToMap

itemToMap

attributeValue

tableMetadata

itemType

attributeNames

isAbstract

converterForAttribute

initialize

concreteTableSchema

isInitialized