Module spring.data.relational

Package org.springframework.data.relational.core.conversion

Interface RelationalConverter

All Known Implementing Classes:

AbstractRelationalConverter, BasicRelationalConverter, MappingRelationalConverter

public interface RelationalConverter

A RelationalConverter is responsible for converting for values to the native relational representation and vice versa.

Author:

Mark Paluch, Jens Schauder

Method Summary

Modifier and Type	Method	Description
default <T> T	createInstance(PersistentEntity<T,RelationalPersistentProperty> entity, Function<Parameter<?,RelationalPersistentProperty>,Object> parameterValueProvider)	Deprecated. since 3.2, use read(java.lang.Class<R>, org.springframework.data.relational.domain.RowDocument) method instead.
ConversionService	getConversionService()	Returns the underlying ConversionService used by the converter.
EntityInstantiators	getEntityInstantiators()	Return the underlying EntityInstantiators.
MappingContext<? extends RelationalPersistentEntity<?>,? extends RelationalPersistentProperty>	getMappingContext()	Returns the underlying MappingContext used by the converter.
<T> PersistentPropertyPathAccessor<T>	getPropertyAccessor(PersistentEntity<T,?> persistentEntity, T instance)	Return a PersistentPropertyAccessor to access property values of the instance.
<M, D> EntityProjection<M,D>	introspectProjection(Class<M> resultType, Class<D> entityType)	Introspect the given result type in the context of the entity type whether the returned type is a projection and what property paths are participating in the projection.
<R> R	project(EntityProjection<R,?> descriptor, RowDocument document)	Apply a projection to RowDocument and return the projection return type R.
<R> R	read(Class<R> type, RowDocument source)	Read a RowDocument into the requested aggregate type.
Object	readValue(Object value, TypeInformation<?> type)	Read a relational value into the desired destination type.
Object	writeValue(Object value, TypeInformation<?> type)	Write a property value into a relational type that can be stored natively.

Method Details

getConversionService

ConversionService getConversionService()

Returns the underlying ConversionService used by the converter.

Returns:

never null.

getEntityInstantiators

EntityInstantiators getEntityInstantiators()

Return the underlying EntityInstantiators.

Since:

2.3

getMappingContext

MappingContext<? extends RelationalPersistentEntity<?>,? extends RelationalPersistentProperty> getMappingContext()

Returns the underlying MappingContext used by the converter.

Returns:

never null

createInstance

@Deprecated(since="3.2")
default <T> T createInstance(PersistentEntity<T,RelationalPersistentProperty> entity,
 Function<Parameter<?,RelationalPersistentProperty>,Object> parameterValueProvider)

Deprecated.

since 3.2, use read(java.lang.Class<R>, org.springframework.data.relational.domain.RowDocument) method instead.

Create a new instance of PersistentEntity given ParameterValueProvider to obtain constructor properties.

Type Parameters:

T - the type of entity to create.

Parameters:

entity - the kind of entity to create. Must not be null.

parameterValueProvider - a function that provides the value to pass to a constructor, given a Parameter. Must not be null.

Returns:

the instantiated entity. Guaranteed to be not null.

getPropertyAccessor

<T> PersistentPropertyPathAccessor<T> getPropertyAccessor(PersistentEntity<T,?> persistentEntity,
 T instance)

Return a PersistentPropertyAccessor to access property values of the instance.

Parameters:

persistentEntity - the kind of entity to operate on. Must not be null.

instance - the instance to operate on. Must not be null.

Returns:

guaranteed to be not null.

introspectProjection

<M,
D> EntityProjection<M,D> introspectProjection(Class<M> resultType,
 Class<D> entityType)

Introspect the given result type in the context of the entity type whether the returned type is a projection and what property paths are participating in the projection.

Parameters:

resultType - the type to project on. Must not be null.

entityType - the source domain type. Must not be null.

Returns:

the introspection result.

Since:

3.2

See Also:

• EntityProjectionIntrospector.introspect(Class, Class)

project

<R> R project(EntityProjection<R,?> descriptor,
 RowDocument document)

Apply a projection to RowDocument and return the projection return type R. Non-projecting descriptors fall back to regular object materialization.

Parameters:

descriptor - the projection descriptor, must not be null.

document - must not be null.

Returns:

a new instance of the projection return type R.

Since:

3.2

read

<R> R read(Class<R> type,
 RowDocument source)

Read a RowDocument into the requested aggregate type.

Type Parameters:

R - aggregate type.

Parameters:

type - target aggregate type.

source - source RowDocument.

Returns:

the converted object.

Since:

3.2

readValue

@Nullable
Object readValue(@Nullable
 Object value,
 TypeInformation<?> type)

Read a relational value into the desired destination type.

Parameters:

value - a value as it is returned by the driver accessing the persistence store. May be null.

type - TypeInformation into which the value is to be converted. Must not be null.

Returns:

The converted value. May be null.

writeValue

@Nullable
Object writeValue(@Nullable
 Object value,
 TypeInformation<?> type)

Write a property value into a relational type that can be stored natively.

Parameters:

value - a value as it is used in the object model. May be null.

type - TypeInformation into which the value is to be converted. Must not be null.

Returns:

The converted value. May be null.