Option (Protelis unspecified Javadoc API)

java.lang.Object
- org.protelis.lang.datatype.Option<E>

Type Parameters:

E - the type of instance that can be contained. Option is naturally covariant on this type, so it is safe to cast an Option<T> to Option<S> for any supertype S of T.

All Implemented Interfaces:

java.io.Serializable
```
public final class Option<E>
extends java.lang.Object
implements java.io.Serializable
```
An immutable object that may contain a non-null reference to another object. Each instance of this type either contains a non-null reference, or contains nothing (in which case we say that the reference is "absent"); it is never said to "contain null".
A non-null Option<E> reference can be used as a replacement for a nullable T reference. It allows you to represent "a T that must be present" and a "a T that might be absent" as two distinct types in your program, which can aid clarity. Protelis recommends to import and use Option when interacting with Java methods that may return null.

See Also:

Serialized Form

Field Summary

Fields
Modifier and Type Field and Description

static java.lang.Object JAVA_NULL
Returns the Java null value.

Fields
Modifier and Type	Field and Description
`static java.lang.Object`	`JAVA_NULL` Returns the Java null value.

Method Summary

All Methods Static Methods Instance Methods Concrete Methods
Modifier and Type	Method and Description
`static <E> Option<E>`	`absent()` Returns an empty `Option` instance.
`java.util.Set<E>`	`asSet()`
`static <E> Option<E>`	`empty()` Returns an empty `Option` instance.
`boolean`	`equals(java.lang.Object obj)`
`Option<E>`	`filter(ExecutionContext ctx, FunctionDefinition test)` Filter operation using Protelis functions.
`Option<E>`	`filter(java.util.function.Predicate<? super E> test)`
`Option<E>`	`filterNot(ExecutionContext ctx, FunctionDefinition test)` Inverse filter operation using Protelis functions.
`Option<E>`	`filterNot(java.util.function.Predicate<? super E> test)` Inverse of `filter(Predicate)`.
`<X> Option<X>`	`flatMap(ExecutionContext ctx, FunctionDefinition fun)` `Optional.flatMap(Function)` function callable via Protelis.
`<X> Option<X>`	`flatMap(java.util.function.Function<? super E,Option<X>> fun)`
`static <E> Option<E>`	`fromGuava(com.google.common.base.Optional<E> origin)`
`static <E> Option<E>`	`fromJavaUtil(java.util.Optional<E> origin)`
`static <E> Option<E>`	`fromNullable(E value)` Returns an `Option` describing the specified value, if non-null, otherwise returns an empty `Option`.
`E`	`get()`
`int`	`hashCode()`
`boolean`	`isAbsent()`
`boolean`	`isEmpty()`
`boolean`	`isPresent()`
`Option<java.lang.Object>`	`map(ExecutionContext ctx, FunctionDefinition mapper)`
`<X> Option<X>`	`map(java.util.function.Function<? super E,? extends X> mapper)`
`Option<E>`	`merge(Option<E> other, java.util.function.BinaryOperator<E> combiner)` If both options are present, the combiner function is executed on the Option contents.
`static <E> Option<E>`	`of(E value)` Returns an `Option` describing the specified value, if non-null, otherwise returns an empty `Option`.
`static <E> Option<E>`	`ofNullable(E value)` Returns an `Option` describing the specified value, if non-null, otherwise returns an empty `Option`.
`Option<? extends E>`	`or(Option<? extends E> other)` Return the value if present, otherwise return `other`.
`Option<? extends E>`	`or(java.util.Optional<? extends E> other)` Return the value if present, otherwise return `other`.
`Option<? extends E>`	`or(com.google.common.base.Optional<? extends E> other)` Return the value if present, otherwise return `other`.
`E`	`orElse(E other)` Return the value if present, otherwise return `other`.
`E`	`orElseGet(ExecutionContext ctx, FunctionDefinition other)` Return the value if present, otherwise invoke `other` and return the result of that invocation.
`E`	`orElseGet(java.util.function.Supplier<? extends E> other)` Return the value if present, otherwise invoke `other` and return the result of that invocation.
`<X extends java.lang.RuntimeException> E`	`orElseThrow(java.util.function.Supplier<? extends X> exceptionSupplier)` Return the contained value, if present, otherwise throw an exception to be created by the provided supplier.
`com.google.common.base.Optional<E>`	`toGuava()`
`java.util.Optional<E>`	`toJavaUtil()`
`java.lang.String`	`toString()`
`Option<java.lang.Object>`	`transform(ExecutionContext ctx, FunctionDefinition mapper)`
`<X> Option<X>`	`transform(java.util.function.Function<? super E,? extends X> mapper)`

Methods inherited from class java.lang.Object
clone, finalize, getClass, notify, notifyAll, wait, wait, wait

- Field Detail
  - JAVA_NULL
```
public static final java.lang.Object JAVA_NULL
```
    Returns the Java null value. To be used ONLY for interacting with Java. Protelis is null-intolerant.
- Method Detail
  - asSet
```
public java.util.Set<E> asSet()
```
    Returns:
    
    a set representation of the Option, for compatibility with Optional
  - equals
```
public boolean equals(java.lang.Object obj)
```
    Overrides:
    
    equals in class java.lang.Object
  - filter
```
public Option<E> filter(ExecutionContext ctx,
                        FunctionDefinition test)
```
    Filter operation using Protelis functions.
    
    Parameters:
    
    ctx - ExecutionContext the execution context
    
    test - the function used as predicate. Must return boolean.
    
    Returns:
    
    If the test passes, the Option is unchanged. Otherwise, it's emptied.
  - filter
```
public Option<E> filter(java.util.function.Predicate<? super E> test)
```
    Parameters:
    
    test - predicate to test
    
    Returns:
    
    an Option describing the value of this Option if a value is present and the value matches the given predicate, otherwise an empty Option
    
    See Also:
    
    Optional.filter(Predicate)
  - filterNot
```
public Option<E> filterNot(ExecutionContext ctx,
                           FunctionDefinition test)
```
    Inverse filter operation using Protelis functions.
    
    Parameters:
    
    ctx - ExecutionContext the execution context
    
    test - the function used as predicate. Must return boolean.
    
    Returns:
    
    If the test passes, the Option is emptied, otherwise, it's left unchanged.
  - filterNot
```
public Option<E> filterNot(java.util.function.Predicate<? super E> test)
```
    Inverse of filter(Predicate).
    
    Parameters:
    
    test - predicate to test
    
    Returns:
    
    an Option describing the value of this Option if a value is present and the value does not match the given predicate, otherwise an empty Option
    
    See Also:
    
    Optional.filter(Predicate)
  - flatMap
```
public <X> Option<X> flatMap(ExecutionContext ctx,
                             FunctionDefinition fun)
```
    Optional.flatMap(Function) function callable via Protelis.
    
    Type Parameters:
    
    X - The type parameter to the Optional returned
    
    Parameters:
    
    ctx - ExecutionContext
    
    fun - Function to run. Must accept a single parameter and return an Option, Optional, Optional, or a Java class with a get() method and one of the following methods isPresent(), isNotPresent(), isEmpty(), isAbsent():
    
    Returns:
    
    the result of applying an Optional-bearing mapping function to the value of this Optional, if a value is present, otherwise an empty Optional
  - flatMap
```
public <X> Option<X> flatMap(java.util.function.Function<? super E,Option<X>> fun)
```
    Type Parameters:
    
    X - The type parameter to the Optional returned
    
    Parameters:
    
    fun - a mapping function to apply to the value, if present the mapping function
    
    Returns:
    
    the result of applying an Optional-bearing mapping function to the value of this Optional, if a value is present, otherwise an empty Optional
    
    See Also:
    
    Optional.flatMap(Function)
  - get
```
public E get()
```
    Returns:
    
    the internal value of the Option, or a RuntimeException if absent.
  - hashCode
```
public int hashCode()
```
    Overrides:
    
    hashCode in class java.lang.Object
  - isAbsent
```
public boolean isAbsent()
```
    Returns:
    
    true if the Option has no value
  - isEmpty
```
public boolean isEmpty()
```
    Returns:
    
    true if the Option has no value
  - isPresent
```
public boolean isPresent()
```
    Returns:
    
    true if the Option is holding a value
  - map
```
public Option<java.lang.Object> map(ExecutionContext ctx,
                                    FunctionDefinition mapper)
```
    Parameters:
    
    ctx - ExecutionContext
    
    mapper - a mapping function to apply to the value, if present
    
    Returns:
    
    an Option describing the result of applying a mapping function to the value of this Option, if a value is present, otherwise an empty Option.
  - map
```
public <X> Option<X> map(java.util.function.Function<? super E,? extends X> mapper)
```
    Type Parameters:
    
    X - The type of the result of the mapping function
    
    Parameters:
    
    mapper - a mapping function to apply to the value, if present
    
    Returns:
    
    an Option describing the result of applying a mapping function to the value of this Option, if a value is present, otherwise an empty Option
    
    See Also:
    
    Optional.map(Function)
  - merge
```
public Option<E> merge(Option<E> other,
                       java.util.function.BinaryOperator<E> combiner)
```
    If both options are present, the combiner function is executed on the Option contents. Otherwise, if an Option is present, it is returned. Finally, if both are empty, an empty Option is returned.
    
    Parameters:
    
    other - the other option
    
    combiner - the combining (reduction) function
    
    Returns:
    
    Option.of(combiner(this.get(), other.get()) if both are present, the only present option iff one is present, an empty option otherwise
  - or
```
public Option<? extends E> or(java.util.Optional<? extends E> other)
```
    Return the value if present, otherwise return other.
    
    Parameters:
    
    other - alternative
    
    Returns:
    
    this Optional if it has a value present; other otherwise.
  - or
```
public Option<? extends E> or(Option<? extends E> other)
```
    Return the value if present, otherwise return other.
    
    Parameters:
    
    other - alternative
    
    Returns:
    
    this Optional if it has a value present; other otherwise.
  - or
```
public Option<? extends E> or(com.google.common.base.Optional<? extends E> other)
```
    Return the value if present, otherwise return other.
    
    Parameters:
    
    other - alternative
    
    Returns:
    
    this Optional if it has a value present; other otherwise.
  - orElse
```
public E orElse(E 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 E orElseGet(ExecutionContext ctx,
                   FunctionDefinition other)
```
    Return the value if present, otherwise invoke other and return the result of that invocation.
    
    Parameters:
    
    ctx - ExecutionContext
    
    other - a 0-ary protelis function
    
    Returns:
    
    the value if present otherwise the result of other.get()
  - orElseGet
```
public E orElseGet(java.util.function.Supplier<? extends E> other)
```
    Return the value if present, otherwise invoke other and return the result of that invocation.
    
    Parameters:
    
    other - a Supplier whose result is returned if no value is present
    
    Returns:
    
    the value if present otherwise the result of other.get()
  - orElseThrow
```
public <X extends java.lang.RuntimeException> E orElseThrow(java.util.function.Supplier<? extends X> exceptionSupplier)
```
    Return the contained value, if present, otherwise throw an exception to be created by the provided supplier.
    
    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
  - toGuava
```
public com.google.common.base.Optional<E> toGuava()
```
    Returns:
    
    a Guava compatible view of this Option
  - toJavaUtil
```
public java.util.Optional<E> toJavaUtil()
```
    Returns:
    
    a Optional view of this Option
  - toString
```
public java.lang.String toString()
```
    Overrides:
    
    toString in class java.lang.Object
  - transform
```
public Option<java.lang.Object> transform(ExecutionContext ctx,
                                          FunctionDefinition mapper)
```
    Parameters:
    
    ctx - ExecutionContext
    
    mapper - a mapping function to apply to the value, if present
    
    Returns:
    
    an Option describing the result of applying a mapping function to the value of this Option, if a value is present, otherwise an empty Option.
  - transform
```
public <X> Option<X> transform(java.util.function.Function<? super E,? extends X> mapper)
```
    Type Parameters:
    
    X - The type of the result of the mapping function
    
    Parameters:
    
    mapper - a mapping function to apply to the value, if present
    
    Returns:
    
    an Option describing the result of applying a mapping function to the value of this Option, if a value is present, otherwise an empty Option
    
    See Also:
    
    Optional.map(Function)
  - absent
```
public static <E> Option<E> absent()
```
    Returns an empty Option instance. No value is present for this Optional.
    
    Type Parameters:
    
    E - Type of the non-existent value
    
    Returns:
    
    an empty Option
  - empty
```
public static <E> Option<E> empty()
```
    Returns an empty Option instance. No value is present for this Optional.
    
    Type Parameters:
    
    E - Type of the non-existent value
    
    Returns:
    
    an empty Option
  - fromGuava
```
public static <E> Option<E> fromGuava(com.google.common.base.Optional<E> origin)
```
    Type Parameters:
    
    E - option type
    
    Parameters:
    
    origin - the guava Optional
    
    Returns:
    
    a Protelis view of the Guava Option
  - fromJavaUtil
```
public static <E> Option<E> fromJavaUtil(java.util.Optional<E> origin)
```
    Type Parameters:
    
    E - option type
    
    Parameters:
    
    origin - the Java Optional
    
    Returns:
    
    a Protelis view of the Java Option
  - fromNullable
```
public static <E> Option<E> fromNullable(E value)
```
    Returns an Option describing the specified value, if non-null, otherwise returns an empty Option.
    
    Type Parameters:
    
    E - the class of the value
    
    Parameters:
    
    value - the possibly-null value to describe
    
    Returns:
    
    an Option with a present value if the specified value is non-null, otherwise an empty Option
  - of
```
public static <E> Option<E> of(E value)
```
    Returns an Option describing the specified value, if non-null, otherwise returns an empty Option.
    
    Type Parameters:
    
    E - the class of the value
    
    Parameters:
    
    value - the possibly-null value to describe
    
    Returns:
    
    an Option with a present value if the specified value is non-null, otherwise an empty Option
  - ofNullable
```
public static <E> Option<E> ofNullable(E value)
```
    Returns an Option describing the specified value, if non-null, otherwise returns an empty Option.
    
    Type Parameters:
    
    E - the class of the value
    
    Parameters:
    
    value - the possibly-null value to describe
    
    Returns:
    
    an Option with a present value if the specified value is non-null, otherwise an empty Option

Class Option<E>

Field Summary

Method Summary

Methods inherited from class java.lang.Object

Field Detail

JAVA_NULL

Method Detail

asSet

equals

filter

filter

filterNot

filterNot

flatMap

flatMap

get

hashCode

isAbsent

isEmpty

isPresent

map

map

merge

or

or

or

orElse

orElseGet

orElseGet

orElseThrow

toGuava

toJavaUtil

toString

transform

transform

absent

empty

fromGuava

fromJavaUtil

fromNullable

of

ofNullable