Module io.helidon.config
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
    Description
    <T> T
    map(Config config, GenericType<T> type)
    Convert the specified Config node into the target type specified by GenericType.
    <T> T
    map(Config config, Class<T> type)
    Converts the specified Config node to the target type.
    <T> T
    map(String value, GenericType<T> type, String key)
    Converts the value to the target generic type.
    <T> T
    map(String value, Class<T> type, String key)
    Converts the value to the target type.

  • Method Details

    • 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