Package io.helidon.config.spi

Interface ConfigMapper

public interface ConfigMapper

Config mapper is provided to ConfigMapperProvider to help transformation of complex structures.

Method Summary

Modifier and Type	Method and Description
<T> T	map(Config config, Class<T> type) Converts the specified Config node to the target type.
<T> T	map(Config config, GenericType<T> type) Convert the specified Config node into the target type specified by GenericType.
<T> T	map(String value, Class<T> type, String key) Converts the value to the target type.
<T> T	map(String value, GenericType<T> type, String key) Converts the value to the target generic type.

Method Detail

map

<T> T map(Config config,
          GenericType<T> type)
   throws MissingValueException,
          ConfigMappingException

Convert the specified Config node into the target type specified by GenericType. You can use GenericType.create(Type) if needed to wrap a parametrized type.

Type Parameters:

T - type of the result

Parameters:

config - config node to convert

type - type to extract generics types from (to prevent type erasure)

Returns:

converted value, never null

Throws:

MissingValueException - in case a value is expected and not found (either on this config node or on a subnode)

ConfigMappingException - in case the config node cannot be converted into the expected type (e.g. value is "hello" and expected type is List<Integer>)

map

<T> T map(Config config,
          Class<T> type)
   throws MissingValueException,
          ConfigMappingException

Converts the specified Config node to the target type.

The method uses the mapper function instance associated with the specified type to convert the Config subtree. If there is none it tries to find one from ConfigMapperProvider.mapper(Class) from configured mapper providers. If none is found, mapping will throw a ConfigMappingException.

Type Parameters:

T - type to which the config node is to be transformed

Parameters:

config - config node to be transformed

type - type to which the config node is to be transformed

Returns:

transformed value of type T; never returns null

Throws:

MissingValueException - in case the configuration node does not represent an existing configuration node

ConfigMappingException - in case the mapper fails to map the existing configuration value to an instance of a given Java type

map

<T> T map(String value,
          Class<T> type,
          String key)
   throws MissingValueException,
          ConfigMappingException

Converts the value to the target type.

Type Parameters:

T - type of the converted value

Parameters:

value - String value to convert

type - type to convert to

key - configuration key to be used to create appropriate exceptions

Returns:

value converted to the correct type

Throws:

MissingValueException - iin case a value is expected and not found (e.g. when trying to convert to a complex object)

ConfigMappingException - in case the String cannot be converted to the expected type

map

<T> T map(String value,
          GenericType<T> type,
          String key)
   throws MissingValueException,
          ConfigMappingException

Converts the value to the target generic type.

Type Parameters:

T - type of the converted value

Parameters:

value - String value to convert

type - generic type to convert to

key - configuration key to be used to create appropriate exceptions

Returns:

value converted to the correct type

Throws:

MissingValueException - iin case a value is expected and not found (e.g. when trying to convert to a complex object)

ConfigMappingException - in case the String cannot be converted to the expected type