OptionalLong (Java Platform SE 8 ) (original) (raw)

java.lang.Object
- java.util.OptionalLong

public final class OptionalLong
extends Object
A container object which may or may not contain a long value. If a value is present, isPresent() will return true andgetAsLong() will return the value.
Additional methods that depend on the presence or absence of a contained value are provided, such as orElse() (return a default value if value not present) andifPresent() (execute a block of code if the value is present).
This is a value-based class; use of identity-sensitive operations (including reference equality (==), identity hash code, or synchronization) on instances ofOptionalLong may have unpredictable results and should be avoided.
Since:
1.8

Method Summary

All Methods Static Methods Instance Methods Concrete Methods

Modifier and Type	Method	Description
static OptionalLong	empty()	Returns an empty OptionalLong instance.
boolean	equals(Object obj)	Indicates whether some other object is "equal to" this OptionalLong.
long	getAsLong()	If a value is present in this OptionalLong, 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(LongConsumer 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 OptionalLong	of(long value)	Return an OptionalLong with the specified value present.
long	orElse(long other)	Return the value if present, otherwise return other.
long	orElseGet(LongSupplier other)	Return the value if present, otherwise invoke other and return the result of that invocation.
<X extends Throwable>long	orElseThrow(Supplier 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](../../java/lang/Object.html "class in java.lang")  
   `[clone](../../java/lang/Object.html#clone--), [finalize](../../java/lang/Object.html#finalize--), [getClass](../../java/lang/Object.html#getClass--), [notify](../../java/lang/Object.html#notify--), [notifyAll](../../java/lang/Object.html#notifyAll--), [wait](../../java/lang/Object.html#wait--), [wait](../../java/lang/Object.html#wait-long-), [wait](../../java/lang/Object.html#wait-long-int-)`

Method Detail

 * #### empty  
 public static [OptionalLong](../../java/util/OptionalLong.html "class in java.util") empty()  
 Returns an empty `OptionalLong` instance. No value is present for this OptionalLong.  
 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()](../../java/util/OptionalLong.html#isPresent--).  
 Returns:  
 an empty `OptionalLong`.  
 * #### of  
 public static [OptionalLong](../../java/util/OptionalLong.html "class in java.util") of(long value)  
 Return an `OptionalLong` with the specified value present.  
 Parameters:  
 `value` \- the value to be present  
 Returns:  
 an `OptionalLong` with the value present  
 * #### getAsLong  
 public long getAsLong()  
 If a value is present in this `OptionalLong`, returns the value, otherwise throws `NoSuchElementException`.  
 Returns:  
 the value held by this `OptionalLong`  
 Throws:  
 `[NoSuchElementException](../../java/util/NoSuchElementException.html "class in java.util")` \- if there is no value present  
 See Also:  
 [isPresent()](../../java/util/OptionalLong.html#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([LongConsumer](../../java/util/function/LongConsumer.html "interface in java.util.function") 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](../../java/lang/NullPointerException.html "class in java.lang")` \- if value is present and `consumer` is null  
 * #### orElse  
 public long orElse(long 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 long orElseGet([LongSupplier](../../java/util/function/LongSupplier.html "interface in java.util.function") other)  
 Return the value if present, otherwise invoke `other` and return the result of that invocation.  
 Parameters:  
 `other` \- a `LongSupplier` whose result is returned if no value is present  
 Returns:  
 the value if present otherwise the result of `other.getAsLong()`  
 Throws:  
 `[NullPointerException](../../java/lang/NullPointerException.html "class in java.lang")` \- if value is not present and `other` is null  
 * #### orElseThrow  
 public <X extends [Throwable](../../java/lang/Throwable.html "class in java.lang")> long orElseThrow([Supplier](../../java/util/function/Supplier.html "interface in java.util.function")<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](../../java/lang/NullPointerException.html "class in java.lang")` \- if no value is present and`exceptionSupplier` is null  
 `X extends [Throwable](../../java/lang/Throwable.html "class in java.lang")`  
 * #### equals  
 public boolean equals([Object](../../java/lang/Object.html "class in java.lang") obj)  
 Indicates whether some other object is "equal to" this OptionalLong. The other object is considered equal if:  
          * it is also an `OptionalLong` and;  
          * both instances have no value present or;  
          * the present values are "equal to" each other via `==`.  
 Overrides:  
 `[equals](../../java/lang/Object.html#equals-java.lang.Object-)` in class `[Object](../../java/lang/Object.html "class in java.lang")`  
 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()](../../java/lang/Object.html#hashCode--), [HashMap](../../java/util/HashMap.html "class in java.util")  
 * #### 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](../../java/lang/Object.html#hashCode--)` in class `[Object](../../java/lang/Object.html "class in java.lang")`  
 Returns:  
 hash code value of the present value or 0 if no value is present  
 See Also:  
 [Object.equals(java.lang.Object)](../../java/lang/Object.html#equals-java.lang.Object-), [System.identityHashCode(java.lang.Object)](../../java/lang/System.html#identityHashCode-java.lang.Object-)  
 * #### toString  
 public [String](../../java/lang/String.html "class in java.lang") 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](../../java/lang/Object.html#toString--)` in class `[Object](../../java/lang/Object.html "class in java.lang")`  
 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

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OptionalLong (Java Platform SE 8 ) (original) (raw)

Method Summary

Method Detail