public final class OptionalDouble
extends Object 

Since:

1.8

• Method Summary

  All Methods

  Modifier and Type	Method	Description
  static OptionalDouble	empty ()	Returns an empty OptionalDouble instance.
  boolean	equals (Object obj)	Indicates whether some other object is "equal to" this OptionalDouble.
  double	getAsDouble ()	If a value is present in this OptionalDouble, returns the value, otherwise throws NoSuchElementException.
  int	hashCode ()	Returns the hash code value of the present value, if any, or 0 (zero) if no value is present.
  void	ifPresent (DoubleConsumer consumer)	Have the specified consumer accept the value if a value is present, otherwise do nothing.
  boolean	isPresent ()	Return true if there is a value present, otherwise false.
  static OptionalDouble	of (double value)	Return an OptionalDouble with the specified value present.
  double	orElse (double other)	Return the value if present, otherwise return other.
  double	orElseGet (DoubleSupplier other)	Return the value if present, otherwise invoke other and return the result of that invocation.
  <X extends Throwable> double	orElseThrow (Supplier<X> exceptionSupplier)	Return the contained value, if present, otherwise throw an exception to be created by the provided supplier.
  String	toString ()	Returns a string representation of the object.

  • Methods inherited from class java.lang.Object

    clone, finalize, getClass, notify, notifyAll, wait, wait, wait

• Method Detail

  • empty

    public static OptionalDouble empty()

    Returns an empty OptionalDouble instance. No value is present for this OptionalDouble.

    API Note:

    Though it may be tempting to do so, avoid testing if an object is empty by comparing with == against instances returned by Option.empty(). There is no guarantee that it is a singleton. Instead, use isPresent().

    Returns:

    an empty OptionalDouble.

  • of

    public static OptionalDouble of(double value)

    Return an OptionalDouble with the specified value present.

    Parameters:

    value - the value to be present

    Returns:

    an OptionalDouble with the value present

  • getAsDouble

    public double getAsDouble()

    If a value is present in this OptionalDouble, returns the value, otherwise throws NoSuchElementException.

    Returns:

    the value held by this OptionalDouble

    Throws:

    NoSuchElementException - if there is no value present

    See Also:

    isPresent()

  • isPresent

    public boolean isPresent()

    Return true if there is a value present, otherwise false.

    Returns:

    true if there is a value present, otherwise false

  • ifPresent

    public void ifPresent(DoubleConsumer consumer)

    Have the specified consumer accept the value if a value is present, otherwise do nothing.

    Parameters:

    consumer - block to be executed if a value is present

    Throws:

    NullPointerException - if value is present and consumer is null

  • orElse

    public double orElse(double other)

    Return the value if present, otherwise return other.

    Parameters:

    other - the value to be returned if there is no value present

    Returns:

    the value, if present, otherwise other

  • orElseGet

    public double orElseGet(DoubleSupplier other)

    Return the value if present, otherwise invoke other and return the result of that invocation.

    Parameters:

    other - a DoubleSupplier whose result is returned if no value is present

    Returns:

    the value if present otherwise the result of other.getAsDouble()

    Throws:

    NullPointerException - if value is not present and other is null

  • orElseThrow

    public <X extends Throwable> double orElseThrow(Supplier<X> exceptionSupplier)
     throws X

    Return the contained value, if present, otherwise throw an exception to be created by the provided supplier.

    API Note:

    A method reference to the exception constructor with an empty argument list can be used as the supplier. For example, IllegalStateException::new

    Type Parameters:

    X - Type of the exception to be thrown

    Parameters:

    exceptionSupplier - The supplier which will return the exception to be thrown

    Returns:

    the present value

    Throws:

    X - if there is no value present

    NullPointerException - if no value is present and exceptionSupplier is null

    X extends Throwable

  • equals

    public boolean equals(Object obj)

    Indicates whether some other object is "equal to" this OptionalDouble. The other object is considered equal if:

    • it is also an OptionalDouble and;
    • both instances have no value present or;
    • the present values are "equal to" each other via Double.compare() == 0.

    Overrides:

    equals in class Object

    Parameters:

    obj - an object to be tested for equality

    Returns:

    {code true} if the other object is "equal to" this object otherwise false

    See Also:

    Object.hashCode(), HashMap

  • hashCode

    public int hashCode()

    Returns the hash code value of the present value, if any, or 0 (zero) if no value is present.

    Overrides:

    hashCode in class Object

    Returns:

    hash code value of the present value or 0 if no value is present

    See Also:

    Object.equals(java.lang.Object), System.identityHashCode(java.lang.Object)

  • toString

    public String toString()

    Returns a string representation of the object. In general, the toString method returns a string that "textually represents" this object. The result should be a concise but informative representation that is easy for a person to read. It is recommended that all subclasses override this method.

    The toString method for class Object returns a string consisting of the name of the class of which the object is an instance, the at-sign character `@', and the unsigned hexadecimal representation of the hash code of the object. In other words, this method returns a string equal to the value of:

     getClass().getName() + '@' + Integer.toHexString(hashCode())
     

    Returns a non-empty string representation of this object suitable for debugging. The exact presentation format is unspecified and may vary between implementations and versions.

    Overrides:

    toString in class Object

    Implementation Requirements:

    If a value is present the result must include its string representation in the result. Empty and present instances must be unambiguously differentiable.

    Returns:

    the string representation of this instance