org.jooq

Interface Converter<T,U>

Type Parameters:

T - The database type - i.e. any type available from SQLDataType

U - The user type

All Superinterfaces:

Serializable

All Known Implementing Classes:

AbstractConverter, Converters, DateToLocalDateConverter, DelegatingConverter, EnumConverter, JPAConverter, TimestampToLocalDateTimeConverter, TimeToLocalTimeConverter

public interface Converter<T,U>
extends Serializable

A Converter for data types.

A general data type conversion interface that can be provided to jOOQ at various places in order to perform custom data type conversion. Conversion is directed, this means that the Converter is used

• to load database types converting them to user types "FROM" the database. Hence, fromType() is the type as defined in the database.
• to store user types converting them to database types "TO" the database. Hence, toType() is the user-defined type

Note: In order to avoid unwanted side-effects, it is highly recommended (yet not required) for from(Object) and to(Object) to be reciprocal. The two methods are reciprocal, if for all X and Y, it can be said that

• if Y.equals(converter.from(X)), then X.equals(converter.to(Y)).
• X.equals(converter.from(converter.to(X)))
• X.equals(converter.to(converter.from(X)))

Furthermore, it is recommended (yet not required) that

• converter.from(null) == null
• converter.to(null) == null

Creating user defined DataTypes

jOOQ provides built in data types through SQLDataType. Users can define their own data types programmatically by calling DataType.asConvertedDataType(Converter) or DataType.asConvertedDataType(Binding), for example. Custom data types can also be defined on generated code using the <forcedType/> configuration, see the manual for more details

Author:

Lukas Eder

Method Summary

Modifier and Type	Method and Description
default <X> Converter<T,X>	andThen(Converter<? super U,X> converter) Chain a converter to this converter.
U	from(T databaseObject) Convert a database object to a user object
Class<T>	fromType() The database type
default Converter<U,T>	inverse() Inverse this converter.
static <T,U> Converter<T,U>	of(Class<T> fromType, Class<U> toType, Function<? super T,? extends U> from, Function<? super U,? extends T> to) Construct a new converter from functions.
static <T,U> Converter<T,U>	ofNullable(Class<T> fromType, Class<U> toType, Function<? super T,? extends U> from, Function<? super U,? extends T> to) Construct a new converter from functions.
T	to(U userObject) Convert a user object to a database object
Class<U>	toType() The user type

Method Detail

from

U from(T databaseObject)

Convert a database object to a user object

Parameters:

databaseObject - The database object

Returns:

The user object

to

T to(U userObject)

Convert a user object to a database object

Parameters:

userObject - The user object

Returns:

The database object

fromType

Class<T> fromType()

The database type

toType

Class<U> toType()

The user type

inverse

default Converter<U,T> inverse()

Inverse this converter.

andThen

default <X> Converter<T,X> andThen(Converter<? super U,X> converter)

Chain a converter to this converter.

of

static <T,U> Converter<T,U> of(Class<T> fromType,
                               Class<U> toType,
                               Function<? super T,? extends U> from,
                               Function<? super U,? extends T> to)

Construct a new converter from functions.

Type Parameters:

T - the database type

U - the user type

Parameters:

fromType - The database type

toType - The user type

from - A function converting from T to U

to - A function converting from U to T

Returns:

The converter.

See Also:

Converter

ofNullable

static <T,U> Converter<T,U> ofNullable(Class<T> fromType,
                                       Class<U> toType,
                                       Function<? super T,? extends U> from,
                                       Function<? super U,? extends T> to)

Construct a new converter from functions.

This works like of(Class, Class, Function, Function), except that both conversion Functions are decorated with a function that always returns null for null inputs.

Example:

 Converter converter =
   Converter.ofNullable(String.class, Integer.class, Integer::parseInt, Object::toString);

 // No exceptions thrown
 assertNull(converter.from(null));
 assertNull(converter.to(null));
 

Type Parameters:

T - the database type

U - the user type

Parameters:

fromType - The database type

toType - The user type

from - A function converting from T to U

to - A function converting from U to T

Returns:

The converter.

See Also:

Converter