Module io.helidon.config
Package io.helidon.config

Interface ConfigValue<T>

Type Parameters:
T - type of the value
All Superinterfaces:
ConfigValue<T>, OptionalValue<T>, Value<T>
public interface ConfigValue<T> extends ConfigValue<T>
A typed value of a Config node.

You can use accessor methods on Config to obtain this value, such as Config.as(Class). A typed value that has all the methods of Optional - including the ones added in JDK9 and newer. In addition it has methods to access config values as supplier().

See Also:

  • Method Details

    • key

      Config.Key key()
      Returns the fully-qualified key of the originating Config node.

      The fully-qualified key is a sequence of tokens derived from the name of each node along the path from the config root to the current node. Tokens are separated by . (the dot character). See name() for more information on the format of each token.

      Specified by:
      key in interface ConfigValue<T>
      Returns:
      current config node key
      See Also:

    • name

      default String name()
      Returns the last token of the fully-qualified key for the originating Config node.

      The name of a node is the last token in its fully-qualified key.

      The exact format of the name depends on the Type of the containing node:

      • from a Config.Type.OBJECT node the token for a child is the name of the object member;
      • from a Config.Type.LIST node the token for a child is a zero-based index of the element, an unsigned base-10 integer value with no leading zeros.

      The ABNF syntax of config key is: 

      
 config-key = *1( key-token *( "." key-token ) )
  key-token = *( unescaped / escaped )
  unescaped = %x00-2D / %x2F-7D / %x7F-10FFFF
            ; %x2E ('.') and %x7E ('~') are excluded from 'unescaped'
    escaped = "~" ( "0" / "1" )
            ; representing '~' and '.', respectively
      Specified by:
      name in interface ConfigValue<T>
      Specified by:
      name in interface Value<T>
      Returns:
      current config node key
      See Also:

    • get

      default T get() throws MissingValueException, ConfigMappingException
      Typed value of the represented Config node. Throws MissingValueException if the node is Config.Type.MISSING type.
      Specified by:
      get in interface OptionalValue<T>
      Specified by:
      get in interface Value<T>
      Returns:
      direct value of this node converted to the expected type
      Throws:
      MissingValueException - in case the node is Config.Type.MISSING.
      ConfigMappingException - in case the value cannot be converted to the expected type

    • as

      <N> ConfigValue<N> as(Function<? super T,? extends N> mapper)
      Convert this ConfigValue to a different type using a mapper function.
      Specified by:
      as in interface ConfigValue<T>
      Specified by:
      as in interface OptionalValue<T>
      Specified by:
      as in interface Value<T>
      Type Parameters:
      N - type of the returned ConfigValue
      Parameters:
      mapper - mapper to map the type of this ConfigValue to a type of the returned ConfigValue
      Returns:
      a new value with the new type

    • supplier

      Supplier<T> supplier()
      Returns a supplier of a typed value. The value provided from the supplier is the latest value available. E.g. in case there is a file config source that is being watched and a value is changed, this supplier would return the latest value, whereas get() would return the original value.

      Note that Supplier.get() can throw a ConfigMappingException or MissingValueException as the get() method.

      Specified by:
      supplier in interface ConfigValue<T>
      Returns:
      a supplier of a typed value

    • supplier

      Supplier<T> supplier(T defaultValue)
      Returns a supplier of a typed value with a default. The value provided from the supplier is the latest value available. E.g. in case there is a file config source that is being watched and a value is changed, this supplier would return the latest value, whereas OptionalValue.orElse(Object) would return the original value.

      Note that Supplier.get() can throw a ConfigMappingException as the OptionalValue.orElse(Object) method.

      Specified by:
      supplier in interface ConfigValue<T>
      Parameters:
      defaultValue - a value to be returned if the supplied value represents a Config node that has no direct value
      Returns:
      a supplier of a typed value

    • optionalSupplier

      Supplier<Optional<T>> optionalSupplier()
      Returns a Supplier of an Optional<T> of the configuration node. Supplier returns a empty if the node does not have a direct value.
      Specified by:
      optionalSupplier in interface ConfigValue<T>
      Returns:
      a supplier of the value as an Optional typed instance, empty in case the node does not have a direct value
      See Also: