Module io.helidon.common.mapper
Package io.helidon.common.mapper

Interface Value<T>

Type Parameters:
T - type of the value
All Known Subinterfaces:
ConfigValue<T>, ConfigValue<T>, DbColumn, Header, HeaderWriteable, OptionalValue<T>
All Known Implementing Classes:
ContentDisposition, DbColumnBase, MongoDbColumn
public interface Value<T>
A typed value with support for mapping (conversion) to other types. For values not backed by an data, see OptionalValue.

  • Method Summary

    Modifier and Type
    Method
    Description
    <N> Value<N>
    as(GenericType<N> type)
    Convert this value to a different type using a mapper.
    <N> Value<N>
    as(Class<N> type)
    Convert this value to a different type using a mapper.
    <N> Value<N>
    as(Function<? super T,? extends N> mapper)
    Convert this Value to a different type using a mapper function.
    Value<Boolean>
    asBoolean()
    Boolean typed value.
    Value<Double>
    asDouble()
    Double typed value.
    Value<Integer>
    asInt()
    Integer typed value.
    Value<Long>
    asLong()
    Long typed value.
    Optional<T>
    asOptional()
    Typed value as Optional.
    Value<String>
    asString()
    String typed value.
    static <T> Value<T>
    create(Mappers mapperManager, String name, T value, GenericType<T> type, String... qualifiers)
    Create a value backed by data.
    static <T> Value<T>
    create(Mappers mapperManager, String name, T value, String... qualifiers)
    Create a value backed by data.
    default Optional<T>
    filter(Predicate<? super T> predicate)
    If a value is present, and the value matches the given predicate, return an Optional describing the value, otherwise return an empty Optional.
    default <U> Optional<U>
    flatMap(Function<? super T,Optional<? extends U>> mapper)
    Apply the provided Optional-bearing mapping function to this value, return that result.
    T
    get()
    Typed value.
    default <N> N
    get(GenericType<N> type)
    Convert this value to a different type using a mapper.
    default <N> N
    get(Class<N> type)
    Convert this value to a different type using a mapper.
    default boolean
    getBoolean()
    Boolean typed value.
    default double
    getDouble()
    Double typed value.
    default int
    getInt()
    Integer typed value.
    default long
    getLong()
    Long typed value.
    default String
    getString()
    String typed value.
    String
    name()
    Name of this value, to potentially troubleshoot the source of it.
    default Stream<T>
    stream()
    If a value is present, returns a sequential Stream containing only that value, otherwise returns an empty Stream.

  • Method Details

    • create

      static <T> Value<T> create(Mappers mapperManager, String name, T value, String... qualifiers)
      Create a value backed by data. The type of the value is "guessed" from the instance provided.
      Type Parameters:
      T - type of the value
      Parameters:
      mapperManager - mapper manager to use for mapping types
      name - name of the value
      value - value, must not be null
      qualifiers - qualifiers of the mapper
      Returns:
      a value backed by data

    • create

      static <T> Value<T> create(Mappers mapperManager, String name, T value, GenericType<T> type, String... qualifiers)
      Create a value backed by data.
      Type Parameters:
      T - type of the value
      Parameters:
      mapperManager - mapper manager to use for mapping types
      name - name of the value
      value - value, must not be null
      type - a more precise type that could be guessed form an instance
      qualifiers - qualifiers of the mapper
      Returns:
      a value backed by data

    • name

      String name()
      Name of this value, to potentially troubleshoot the source of it.
      Returns:
      name of this value, such as "QueryParam("param-name")"

    • get

      T get()
      Typed value.
      Returns:
      direct value

    • get

      default <N> N get(Class<N> type) throws MapperException, NoSuchElementException
      Convert this value to a different type using a mapper.
      Type Parameters:
      N - type we expect
      Parameters:
      type - type to convert to
      Returns:
      converted value
      Throws:
      MapperException - in case the value cannot be converted
      NoSuchElementException - in case the value does not exist

    • get

      default <N> N get(GenericType<N> type) throws MapperException, NoSuchElementException
      Convert this value to a different type using a mapper.
      Type Parameters:
      N - type we expect
      Parameters:
      type - type to convert to
      Returns:
      converted value
      Throws:
      MapperException
      NoSuchElementException

    • as

      <N> Value<N> as(Class<N> type) throws MapperException
      Convert this value to a different type using a mapper.
      Type Parameters:
      N - type we expect
      Parameters:
      type - type to convert to
      Returns:
      converted value
      Throws:
      MapperException - in case the value cannot be converted

    • as

      <N> Value<N> as(GenericType<N> type) throws MapperException
      Convert this value to a different type using a mapper.
      Type Parameters:
      N - type we expect
      Parameters:
      type - type to convert to
      Returns:
      converted value
      Throws:
      MapperException

    • as

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

    • asOptional

      Optional<T> asOptional() throws MapperException
      Typed value as Optional. Returns a empty if this value does not have a backing value present. As this class implements all methods of Optional, this is only a utility method if an actual Optional instance is needed (Optional itself is {code final}).
      Returns:
      value as Optional, empty in case the value does not have a direct value
      Throws:
      MapperException - in case the value cannot be converted to the expected type
      See Also:

    • filter

      default Optional<T> filter(Predicate<? super T> predicate)
      If a value is present, and the value matches the given predicate, return an Optional describing the value, otherwise return an empty Optional.
      Parameters:
      predicate - a predicate to apply to the value, if present
      Returns:
      an Optional describing the value of this Optional if a value is present and the value matches the given predicate, otherwise an empty Optional
      Throws:
      NullPointerException - if the predicate is null
      See Also:

    • flatMap

      default <U> Optional<U> flatMap(Function<? super T,Optional<? extends U>> mapper)
      Apply the provided Optional-bearing mapping function to this value, return that result.
      Type Parameters:
      U - The type parameter to the Optional returned by
      Parameters:
      mapper - a mapping function to apply to the value, if present the mapping function
      Returns:
      the result of applying an Optional-bearing mapping function to this value
      Throws:
      NullPointerException - if the mapping function is null or returns a null result
      See Also:

    • stream

      default Stream<T> stream()
      If a value is present, returns a sequential Stream containing only that value, otherwise returns an empty Stream.
      Returns:
      the optional value as a Stream

    • asBoolean

      Value<Boolean> asBoolean()
      Boolean typed value.
      Returns:
      typed value

    • getBoolean

      default boolean getBoolean()
      Boolean typed value.
      Returns:
      boolean value

    • asString

      Value<String> asString()
      String typed value.
      Returns:
      typed value

    • getString

      default String getString()
      String typed value.
      Returns:
      string value

    • asInt

      Value<Integer> asInt()
      Integer typed value.
      Returns:
      typed value

    • getInt

      default int getInt()
      Integer typed value.
      Returns:
      integer value

    • asLong

      Value<Long> asLong()
      Long typed value.
      Returns:
      typed value

    • getLong

      default long getLong()
      Long typed value.
      Returns:
      long value

    • asDouble

      Value<Double> asDouble()
      Double typed value.
      Returns:
      typed value

    • getDouble

      default double getDouble()
      Double typed value.
      Returns:
      double value