Package Summary Overview Summary

### class:OptionalDouble [NONE]
-                                                                                     public final class OptionalDouble
      extends Object
A container object which may or may not contain a `double` value. If a value is present, `isPresent()` returns `true`. If no value is present, the object is considered empty and `isPresent()` returns `false`. Additional methods that depend on the presence or absence of a contained value are provided, such as `orElse()` (returns a default value if no value is present) and `ifPresent()` (performs an action if a value is present). This is a value-based class; use of identity-sensitive operations (including reference equality (`==`), identity hash code, or synchronization) on instances of `OptionalDouble` may have unpredictable results and should be avoided. API Note: `OptionalDouble` is primarily intended for use as a method return type where there is a clear need to represent "no result." A variable whose type is `OptionalDouble` should never itself be `null`; it should always point to an `OptionalDouble` instance. Since: 1.8

### method:empty() [NONE]
- #### 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 `OptionalDouble.empty()`. There is no guarantee that it is a singleton. Instead, use `isPresent()`. Returns: an empty `OptionalDouble`.

### method:of(double) [NONE]
- #### of
                                                                                                      public static OptionalDouble of​(double value)
Returns an `OptionalDouble` describing the given value. Parameters: `value` - the value to describe Returns: an `OptionalDouble` with the value present

### method:getAsDouble() [NONE]
- #### getAsDouble
      public double getAsDouble()
If a value is present, returns the value, otherwise throws `NoSuchElementException`. API Note: The preferred alternative to this method is `orElseThrow()`. Returns: the value described by this `OptionalDouble` Throws: `NoSuchElementException` - if no value is present

### method:isPresent() [NONE]
- #### isPresent
      public boolean isPresent()
If a value is present, returns `true`, otherwise `false`. Returns: `true` if a value is present, otherwise `false`

### method:isEmpty() [NONE]
- #### isEmpty
      public boolean isEmpty()
If a value is not present, returns `true`, otherwise `false`. Returns: `true` if a value is not present, otherwise `false` Since: 11

### method:ifPresent(java.util.function.DoubleConsumer) [NONE]
- #### ifPresent
                                                                                                      public void ifPresent​(DoubleConsumer action)
If a value is present, performs the given action with the value, otherwise does nothing. Parameters: `action` - the action to be performed, if a value is present Throws: `NullPointerException` - if value is present and the given action is `null`

### method:ifPresentOrElse(java.util.function.DoubleConsumer,java.lang.Runnable) [NONE]
- #### ifPresentOrElse
                                                                                                      public void ifPresentOrElse​(DoubleConsumer action,
                                  Runnable emptyAction)
If a value is present, performs the given action with the value, otherwise performs the given empty-based action. Parameters: `action` - the action to be performed, if a value is present `emptyAction` - the empty-based action to be performed, if no value is present Throws: `NullPointerException` - if a value is present and the given action is `null`, or no value is present and the given empty-based action is `null`. Since: 9

### method:stream() [NONE]
- #### stream
                                                                                                      public DoubleStream stream()
    If a value is present, returns a sequential `DoubleStream` containing only that value, otherwise returns an empty `DoubleStream`. API Note: This method can be used to transform a `Stream` of optional doubles to a `DoubleStream` of present doubles:
             Stream<OptionalDouble> os = ..
             DoubleStream s = os.flatMapToDouble(OptionalDouble::stream)
Returns: the optional value as a `DoubleStream` Since: 9

### method:orElse(double) [NONE]
- #### orElse
      public double orElse​(double other)
If a value is present, returns the value, otherwise returns `other`. Parameters: `other` - the value to be returned, if no value is present Returns: the value, if present, otherwise `other`

### method:orElseGet(java.util.function.DoubleSupplier) [NONE]
- #### orElseGet
                                                                                                      public double orElseGet​(DoubleSupplier supplier)
If a value is present, returns the value, otherwise returns the result produced by the supplying function. Parameters: `supplier` - the supplying function that produces a value to be returned Returns: the value, if present, otherwise the result produced by the supplying function Throws: `NullPointerException` - if no value is present and the supplying function is `null`

### method:orElseThrow() [NONE]
- #### orElseThrow
      public double orElseThrow()
If a value is present, returns the value, otherwise throws `NoSuchElementException`. Returns: the value described by this `OptionalDouble` Throws: `NoSuchElementException` - if no value is present Since: 10

### method:orElseThrow(java.util.function.Supplier) [NONE]
- #### orElseThrow
                                                                                                      public <X extends Throwable> double orElseThrow​(Supplier<? extends X> exceptionSupplier)
                                               throws X extends Throwable
If a value is present, returns the value, otherwise throws an exception produced by the exception supplying function. 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 supplying function that produces an exception to be thrown Returns: the value, if present Throws: `X` - if no value is present `NullPointerException` - if no value is present and the exception supplying function is `null` `X extends Throwable`

### method:equals(java.lang.Object) [NONE]
- #### 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: `true` if the other object is "equal to" this object otherwise `false` See Also: `Object.hashCode()`, `HashMap`

### method:hashCode() [NONE]
- #### hashCode
      public int hashCode()
Returns the hash code of the value, if present, otherwise `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)`

### method:toString() [NONE]
- #### toString
                                                                                                      public String toString()
Returns a non-empty string representation of this `OptionalDouble` 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 `OptionalDouble`s must be unambiguously differentiable. Returns: the string representation of this instance