Optional (Spark 3.5.2 JavaDoc)

Object
- org.apache.spark.api.java.Optional<T>

Type Parameters:

T - type of value held inside

All Implemented Interfaces:

java.io.Serializable
```
public final class Optional<T>
extends Object
implements java.io.Serializable
```
Like java.util.Optional in Java 8, scala.Option in Scala, and com.google.common.base.Optional in Google Guava, this class represents a value of a given type that may or may not exist. It is used in methods that wish to optionally return a value, in preference to returning null.

In fact, the class here is a reimplementation of the essential API of both java.util.Optional and com.google.common.base.Optional. From java.util.Optional, it implements:
From com.google.common.base.Optional it implements:
java.util.Optional itself was not used because at the time, the project did not require Java 8. Using com.google.common.base.Optional has in the past caused serious library version conflicts with Guava that can't be resolved by shading. Hence this work-alike clone.
See Also:

Serialized Form

Method Summary

All Methods Static Methods Instance Methods Concrete Methods
Modifier and Type	Method and Description
`static <T> Optional<T>`	`absent()`
`static <T> Optional<T>`	`empty()`
`boolean`	`equals(Object obj)`
`static <T> Optional<T>`	`fromNullable(T value)`
`T`	`get()`
`int`	`hashCode()`
`boolean`	`isPresent()`
`static <T> Optional<T>`	`of(T value)`
`static <T> Optional<T>`	`ofNullable(T value)`
`T`	`or(T other)`
`T`	`orElse(T other)`
`T`	`orNull()`
`String`	`toString()`

Methods inherited from class Object
getClass, notify, notifyAll, wait, wait, wait

- Method Detail
  - empty
```
public static <T> Optional<T> empty()
```
    Returns:
    
    an empty Optional
  - of
```
public static <T> Optional<T> of(T value)
```
    Parameters:
    
    value - non-null value to wrap
    
    Returns:
    
    Optional wrapping this value
    
    Throws:
    
    NullPointerException - if value is null
  - ofNullable
```
public static <T> Optional<T> ofNullable(T value)
```
    Parameters:
    
    value - value to wrap, which may be null
    
    Returns:
    
    Optional wrapping this value, which may be empty
  - get
```
public T get()
```
    Returns:
    
    the value wrapped by this Optional
    
    Throws:
    
    NullPointerException - if this is empty (contains no value)
  - orElse
```
public T orElse(T other)
```
    Parameters:
    
    other - value to return if this is empty
    
    Returns:
    
    this Optional's value if present, or else the given value
  - isPresent
```
public boolean isPresent()
```
    Returns:
    
    true iff this Optional contains a value (non-empty)
  - absent
```
public static <T> Optional<T> absent()
```
    Returns:
    
    an empty Optional
  - fromNullable
```
public static <T> Optional<T> fromNullable(T value)
```
    Parameters:
    
    value - value to wrap, which may be null
    
    Returns:
    
    Optional wrapping this value, which may be empty
  - or
```
public T or(T other)
```
    Parameters:
    
    other - value to return if this is empty
    
    Returns:
    
    this Optional's value if present, or else the given value
  - orNull
```
public T orNull()
```
    Returns:
    
    this Optional's value if present, or else null
  - equals
```
public boolean equals(Object obj)
```
    Overrides:
    
    equals in class Object
  - hashCode
```
public int hashCode()
```
    Overrides:
    
    hashCode in class Object
  - toString
```
public String toString()
```
    Overrides:
    
    toString in class Object

Class Optional<T>

Method Summary

Methods inherited from class Object

Method Detail

empty

of

ofNullable

get

orElse

isPresent

absent

fromNullable

or

orNull

equals

hashCode

toString