# OptionalLong Added in[API level 24](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels) Summary:[Methods](https://developer.android.com/reference/java/util/OptionalLong#pubmethods)\|[Inherited Methods](https://developer.android.com/reference/java/util/OptionalLong#inhmethods) # OptionalLong ` public final class OptionalLong ` ` extends `[Object](https://developer.android.com/reference/java/lang/Object)` `` ` |---|------------------------| | [java.lang.Object](https://developer.android.com/reference/java/lang/Object) || | ↳ | java.util.OptionalLong |
*** ** * ** *** A container object which may or may not contain a`long`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()](https://developer.android.com/reference/java/util/OptionalLong#orElse(long))(returns a default value if no value is present) and[ifPresent()](https://developer.android.com/reference/java/util/OptionalLong#ifPresent(java.util.function.LongConsumer))(performs an action if a value is present). This is a[value-based](https://docs.oracle.com/en/java/javase/17/docs/api/java.base/java/lang/doc-files/ValueBased.html)class; programmers should treat instances that are[equal](https://developer.android.com/reference/java/util/OptionalLong#equals(java.lang.Object))as interchangeable and should not use instances for synchronization, or unpredictable behavior may occur. For example, in a future release, synchronization may fail. ## Summary | ### Public methods || |------------------------------------------------------------------------------------------------|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| | ` static `[OptionalLong](https://developer.android.com/reference/java/util/OptionalLong) | ` `[empty](https://developer.android.com/reference/java/util/OptionalLong#empty())`() ` Returns an empty`OptionalLong`instance. | | ` boolean` | ` `[equals](https://developer.android.com/reference/java/util/OptionalLong#equals(java.lang.Object))`(`[Object](https://developer.android.com/reference/java/lang/Object)` obj) ` Indicates whether some other object is "equal to" this`OptionalLong`. | | ` long` | ` `[getAsLong](https://developer.android.com/reference/java/util/OptionalLong#getAsLong())`() ` If a value is present, returns the value, otherwise throws`NoSuchElementException`. | | ` int` | ` `[hashCode](https://developer.android.com/reference/java/util/OptionalLong#hashCode())`() ` Returns the hash code of the value, if present, otherwise`0`(zero) if no value is present. | | ` void` | ` `[ifPresent](https://developer.android.com/reference/java/util/OptionalLong#ifPresent(java.util.function.LongConsumer))`(`[LongConsumer](https://developer.android.com/reference/java/util/function/LongConsumer)` action) ` If a value is present, performs the given action with the value, otherwise does nothing. | | ` void` | ` `[ifPresentOrElse](https://developer.android.com/reference/java/util/OptionalLong#ifPresentOrElse(java.util.function.LongConsumer,%20java.lang.Runnable))`(`[LongConsumer](https://developer.android.com/reference/java/util/function/LongConsumer)` action, `[Runnable](https://developer.android.com/reference/java/lang/Runnable)` emptyAction) ` If a value is present, performs the given action with the value, otherwise performs the given empty-based action. | | ` boolean` | ` `[isEmpty](https://developer.android.com/reference/java/util/OptionalLong#isEmpty())`() ` If a value is not present, returns`true`, otherwise`false`. | | ` boolean` | ` `[isPresent](https://developer.android.com/reference/java/util/OptionalLong#isPresent())`() ` If a value is present, returns`true`, otherwise`false`. | | ` static `[OptionalLong](https://developer.android.com/reference/java/util/OptionalLong) | ` `[of](https://developer.android.com/reference/java/util/OptionalLong#of(long))`(long value) ` Returns an`OptionalLong`describing the given value. | | ` long` | ` `[orElse](https://developer.android.com/reference/java/util/OptionalLong#orElse(long))`(long other) ` If a value is present, returns the value, otherwise returns`other`. | | ` long` | ` `[orElseGet](https://developer.android.com/reference/java/util/OptionalLong#orElseGet(java.util.function.LongSupplier))`(`[LongSupplier](https://developer.android.com/reference/java/util/function/LongSupplier)` supplier) ` If a value is present, returns the value, otherwise returns the result produced by the supplying function. | | ` long` | ` `[orElseThrow](https://developer.android.com/reference/java/util/OptionalLong#orElseThrow(java.util.function.Supplier))`(`[Supplier](https://developer.android.com/reference/java/util/function/Supplier)` exceptionSupplier) ` If a value is present, returns the value, otherwise throws an exception produced by the exception supplying function. | | ` long` | ` `[orElseThrow](https://developer.android.com/reference/java/util/OptionalLong#orElseThrow())`() ` If a value is present, returns the value, otherwise throws`NoSuchElementException`. | | ` `[LongStream](https://developer.android.com/reference/java/util/stream/LongStream) | ` `[stream](https://developer.android.com/reference/java/util/OptionalLong#stream())`() ` If a value is present, returns a sequential[LongStream](https://developer.android.com/reference/java/util/stream/LongStream)containing only that value, otherwise returns an empty`LongStream`. | | ` `[String](https://developer.android.com/reference/java/lang/String) | ` `[toString](https://developer.android.com/reference/java/util/OptionalLong#toString())`() ` Returns a non-empty string representation of this`OptionalLong`suitable for debugging. | | ### Inherited methods | |-----------------------|---| | From class` `[java.lang.Object](https://developer.android.com/reference/java/lang/Object)` ` |--------------------------------------------------------------------------------|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| | ` `[Object](https://developer.android.com/reference/java/lang/Object) | ` `[clone](https://developer.android.com/reference/java/lang/Object#clone())`() ` Creates and returns a copy of this object. | | ` boolean` | ` `[equals](https://developer.android.com/reference/java/lang/Object#equals(java.lang.Object))`(`[Object](https://developer.android.com/reference/java/lang/Object)` obj) ` Indicates whether some other object is "equal to" this one. | | ` void` | ` `[finalize](https://developer.android.com/reference/java/lang/Object#finalize())`() ` Called by the garbage collector on an object when garbage collection determines that there are no more references to the object. | | ` final `[Class](https://developer.android.com/reference/java/lang/Class)`` | ` `[getClass](https://developer.android.com/reference/java/lang/Object#getClass())`() ` Returns the runtime class of this`Object`. | | ` int` | ` `[hashCode](https://developer.android.com/reference/java/lang/Object#hashCode())`() ` Returns a hash code value for the object. | | ` final void` | ` `[notify](https://developer.android.com/reference/java/lang/Object#notify())`() ` Wakes up a single thread that is waiting on this object's monitor. | | ` final void` | ` `[notifyAll](https://developer.android.com/reference/java/lang/Object#notifyAll())`() ` Wakes up all threads that are waiting on this object's monitor. | | ` `[String](https://developer.android.com/reference/java/lang/String) | ` `[toString](https://developer.android.com/reference/java/lang/Object#toString())`() ` Returns a string representation of the object. | | ` final void` | ` `[wait](https://developer.android.com/reference/java/lang/Object#wait(long,%20int))`(long timeoutMillis, int nanos) ` Causes the current thread to wait until it is awakened, typically by being*notified* or*interrupted*, or until a certain amount of real time has elapsed. | | ` final void` | ` `[wait](https://developer.android.com/reference/java/lang/Object#wait(long))`(long timeoutMillis) ` Causes the current thread to wait until it is awakened, typically by being*notified* or*interrupted*, or until a certain amount of real time has elapsed. | | ` final void` | ` `[wait](https://developer.android.com/reference/java/lang/Object#wait())`() ` Causes the current thread to wait until it is awakened, typically by being*notified* or*interrupted*. | || ## Public methods ### empty Added in[API level 24](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels) ``` public static OptionalLong 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`==`or`!=`against instances returned by`OptionalLong.empty()`. There is no guarantee that it is a singleton. Instead, use[isEmpty()](https://developer.android.com/reference/java/util/OptionalLong#isEmpty())or[isPresent()](https://developer.android.com/reference/java/util/OptionalLong#isPresent()). | Returns || |--------------------------------------------------------------------------------|--------------------------------| | [OptionalLong](https://developer.android.com/reference/java/util/OptionalLong) | an empty`OptionalLong`.
| ### equals Added in[API level 24](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels) ``` public boolean equals (Object 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`==`.

| Parameters || |-------|------------------------------------------------------| | `obj` | `Object`: an object to be tested for equality
| | Returns || |-----------|-----------------------------------------------------------------------------| | `boolean` | `true`if the other object is "equal to" this object otherwise`false`
| ### getAsLong Added in[API level 24](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels) ``` public long getAsLong () ``` If a value is present, returns the value, otherwise throws`NoSuchElementException`.
##### API Note: - The preferred alternative to this method is[orElseThrow()](https://developer.android.com/reference/java/util/OptionalLong#orElseThrow()). | Returns || |--------|--------------------------------------------------| | `long` | the value described by this`OptionalLong`
| | Throws || |----------------------------------------------------------------------------------------------------|------------------------| | [NoSuchElementException](https://developer.android.com/reference/java/util/NoSuchElementException) | if no value is present | ### hashCode Added in[API level 24](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels) ``` public int hashCode () ``` Returns the hash code of the value, if present, otherwise`0`(zero) if no value is present.
| Returns || |-------|-------------------------------------------------------------------------| | `int` | hash code value of the present value or`0`if no value is present
| ### ifPresent Added in[API level 24](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels) ``` public void ifPresent (LongConsumer action) ``` If a value is present, performs the given action with the value, otherwise does nothing.
| Parameters || |----------|--------------------------------------------------------------------------| | `action` | `LongConsumer`: the action to be performed, if a value is present
| | Throws || |------------------------------------------------------------------------------------------------|---------------------------------------------------| | [NullPointerException](https://developer.android.com/reference/java/lang/NullPointerException) | if value is present and the given action is`null` | ### ifPresentOrElse Added in[API level 33](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels) ``` public void ifPresentOrElse (LongConsumer action, Runnable emptyAction) ``` If a value is present, performs the given action with the value, otherwise performs the given empty-based action.
| Parameters || |---------------|-----------------------------------------------------------------------------------| | `action` | `LongConsumer`: the action to be performed, if a value is present
| | `emptyAction` | `Runnable`: the empty-based action to be performed, if no value is present
| | Throws || |------------------------------------------------------------------------------------------------|------------------------------------------------------------------------------------------------------------------------| | [NullPointerException](https://developer.android.com/reference/java/lang/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`. | ### isEmpty Added in[API level 33](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels) ``` public boolean isEmpty () ``` If a value is not present, returns`true`, otherwise`false`.
| Returns || |-----------|----------------------------------------------------------| | `boolean` | `true`if a value is not present, otherwise`false`
| ### isPresent Added in[API level 24](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels) ``` public boolean isPresent () ``` If a value is present, returns`true`, otherwise`false`.
| Returns || |-----------|------------------------------------------------------| | `boolean` | `true`if a value is present, otherwise`false`
| ### of Added in[API level 24](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels) ``` public static OptionalLong of (long value) ``` Returns an`OptionalLong`describing the given value.
| Parameters || |---------|--------------------------------------| | `value` | `long`: the value to describe
| | Returns || |--------------------------------------------------------------------------------|-----------------------------------------------| | [OptionalLong](https://developer.android.com/reference/java/util/OptionalLong) | an`OptionalLong`with the value present
| ### orElse Added in[API level 24](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels) ``` public long orElse (long other) ``` If a value is present, returns the value, otherwise returns`other`.
| Parameters || |---------|-----------------------------------------------------------------| | `other` | `long`: the value to be returned, if no value is present
| | Returns || |--------|------------------------------------------------| | `long` | the value, if present, otherwise`other`
| ### orElseGet Added in[API level 24](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels) ``` public long orElseGet (LongSupplier supplier) ``` If a value is present, returns the value, otherwise returns the result produced by the supplying function.
| Parameters || |------------|------------------------------------------------------------------------------------| | `supplier` | `LongSupplier`: the supplying function that produces a value to be returned
| | Returns || |--------|---------------------------------------------------------------------------------------| | `long` | the value, if present, otherwise the result produced by the supplying function
| | Throws || |------------------------------------------------------------------------------------------------|------------------------------------------------------------| | [NullPointerException](https://developer.android.com/reference/java/lang/NullPointerException) | if no value is present and the supplying function is`null` | ### orElseThrow Added in[API level 24](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels) ``` public long orElseThrow (Supplier exceptionSupplier) ``` 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` | Parameters || |---------------------|-----------------------------------------------------------------------------------| | `exceptionSupplier` | `Supplier`: the supplying function that produces an exception to be thrown
| | Returns || |--------|------------------------------| | `long` | the value, if present
| | Throws || |------------------------------------------------------------------------------------------------|----------------------------------------------------------------------| | | if no value is present | | [NullPointerException](https://developer.android.com/reference/java/lang/NullPointerException) | if no value is present and the exception supplying function is`null` | | [Throwable](https://developer.android.com/reference/java/lang/Throwable) | | ### orElseThrow Added in[API level 33](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels) ``` public long orElseThrow () ``` If a value is present, returns the value, otherwise throws`NoSuchElementException`.
| Returns || |--------|--------------------------------------------------| | `long` | the value described by this`OptionalLong`
| | Throws || |----------------------------------------------------------------------------------------------------|------------------------| | [NoSuchElementException](https://developer.android.com/reference/java/util/NoSuchElementException) | if no value is present | ### stream Added in[API level 33](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels) ``` public LongStream stream () ``` If a value is present, returns a sequential[LongStream](https://developer.android.com/reference/java/util/stream/LongStream)containing only that value, otherwise returns an empty`LongStream`.
##### API Note: - This method can be used to transform a`Stream`of optional longs to an`LongStream`of present longs: Stream os = .. LongStream s = os.flatMapToLong(OptionalLong::stream) | Returns || |-----------------------------------------------------------------------------------|---------------------------------------------| | [LongStream](https://developer.android.com/reference/java/util/stream/LongStream) | the optional value as an`LongStream`
| ### toString Added in[API level 24](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels) ``` public String toString () ``` Returns a non-empty string representation of this`OptionalLong`suitable for debugging. The exact presentation format is unspecified and may vary between implementations and versions.
##### Implementation Requirements: - If a value is present the result must include its string representation in the result. Empty and present`OptionalLong`s must be unambiguously differentiable. | Returns || |--------------------------------------------------------------------|---------------------------------------------------| | [String](https://developer.android.com/reference/java/lang/String) | the string representation of this instance
|