Record Class Result.Err<Value,Error>

java.lang.Object
java.lang.Record
dmx.fun.Result.Err<Value,Error>
Type Parameters:
Value - the type of the value contained in a successful result, unused here
Error - the type of the error contained in the erroneous result
Record Components:
error - the non-null error value that represents the erroneous result; passing null throws NullPointerException
All Implemented Interfaces:
Result<Value,Error>
Enclosing interface:
Result<Value,Error>
public static record Result.Err<Value,Error>(Error error) extends Record implements Result<Value,Error>
Represents an erroneous result containing an error of type Error.

This record implements the Result interface and represents the "Err" variant of a result. It encapsulates an error value that indicates a failed computation or action.

  • Constructor Details

    • Err

      public Err(Error error)
      Compact canonical constructor — validates that error is non-null.
      Throws:
      NullPointerException - if error is null

  • Method Details

    • toString

      public final String toString()
      Returns a string representation of this record class. The representation contains the name of the class, followed by the name and value of each of the record components.
      Specified by:
      toString in class Record
      Returns:
      a string representation of this object

    • hashCode

      public final int hashCode()
      Returns a hash code value for this object. The value is derived from the hash code of each of the record components.
      Specified by:
      hashCode in class Record
      Returns:
      a hash code value for this object

    • equals

      public final boolean equals(Object o)
      Indicates whether some other object is "equal to" this one. The objects are equal if the other object is of the same class and if all the record components are equal. All components in this record class are compared with Objects::equals(Object,Object).
      Specified by:
      equals in class Record
      Parameters:
      o - the object with which to compare
      Returns:
      true if this object is the same as the o argument; false otherwise.

    • error

      public Error error()
      Returns the value of the error record component.
      Returns:
      the value of the error record component

    • getOrElse

      default Value getOrElse(Value fallback)
      Returns the success value if present, or fallback otherwise.
      Parameters:
      fallback - the non-null fallback value
      Returns:
      the success value, or fallback if this is the error variant
      Throws:
      NullPointerException - if fallback is null

    • getOrElseGet

      default Value getOrElseGet(Supplier<Value> supplier)
      Returns the success value if present, or the value produced by supplier otherwise.
      Parameters:
      supplier - supplier of the fallback value; must not return null
      Returns:
      the success value, or the value produced by supplier
      Throws:
      NullPointerException - if supplier is null or returns null

    • getOrNull

      default Value getOrNull()
      Returns the success value if present, or null otherwise.
      Returns:
      the success value or null

    • getOrThrow

      default Value getOrThrow(Function<Error, ? extends RuntimeException> exMapper)
      Returns the success value if present, or throws an exception mapped from the error.
      Parameters:
      exMapper - maps the error to a RuntimeException; must not return null
      Returns:
      the success value
      Throws:
      NullPointerException - if exMapper is null or returns null
      RuntimeException - the exception produced by exMapper on the error variant

    • stream

      default Stream<Value> stream()
      Returns a single-element stream of the success value, or an empty stream on error.
      Returns:
      a stream of the value or empty

    • fold

      default <R> R fold(Function<Value,R> onSuccess, Function<Error,R> onError)
      Folds this container to a single value by applying the appropriate function.
      Type Parameters:
      R - the result type
      Parameters:
      onSuccess - applied to the success value; must not return null
      onError - applied to the error value; must not return null
      Returns:
      the result of the applied function
      Throws:
      NullPointerException - if either function is null or returns null

    • match

      default void match(Consumer<Value> onSuccess, Consumer<Error> onError)
      Executes one of the two consumers based on the active variant.
      Parameters:
      onSuccess - called with the success value
      onError - called with the error value
      Throws:
      NullPointerException - if either consumer is null

    • toOption

      default Option<Value> toOption()
      Converts this container to an Option. The success variant maps to Option.Some; the error variant maps to Option.none().
      Returns:
      an Option containing the success value, or empty