ru.yandex.bolts.collection
Class Option<T>

java.lang.Object
  java.util.AbstractCollection<E>
      ru.yandex.bolts.collection.impl.AbstractCollectionF<E>
          ru.yandex.bolts.collection.impl.AbstractListF<T>
              ru.yandex.bolts.collection.Option<T>

All Implemented Interfaces:

Serializable, Iterable<T>, Collection<T>, List<T>, CollectionF<T>, IterableF<T>, ListF<T>

Direct Known Subclasses:

Option.None, Option.Some

public abstract class Option<T>
extends AbstractListF<T>
implements Serializable

Port of scala Option.

Author:

Stepan Koltsov

See Also:

Option, Serialized Form

Nested Class Summary

static class	Option.None<T> None.
static class	Option.Some<T> Some.

Field Summary

Fields inherited from class ru.yandex.bolts.collection.impl.AbstractListF

modCount

Method Summary

Option<T>	filter(Function1B<? super T> p) Return collection with only elements that match predicate.
<B> ListF<B>	flatMap(Function<? super T,? extends Collection<B>> f) Flat map
<U> Option<U>	flatMapO(Function<? super T,Option<U>> f) Flat map variant that accept mapper that returns Option instead of Collection
abstract T	get() Get the value.
T	get(int index) Answers the element at the specified location in this List.
static <U> Function<Option<U>,U>	getF() Delegate to get().
static <U> Function<Option<U>,U>	getM() Deprecated.
T	getOrElse(Function0<T> u) If this is some return value of this, or evaluate function and return it value otherwise.
T	getOrElse(T u) If this is some return value of this, or return given value otherwise.
T	getOrNull() getOrElse(null), but works with types better.
<E extends Throwable> T	getOrThrow(E e) Throw specified exception if isEmpty().
<E extends Throwable> T	getOrThrow(Function0<E> e) Throw specified exception if isEmpty().
T	getOrThrow(String message) Throw exception with specified message if this is empty
T	getOrThrow(String message, Object param) Get or throw exception if this is empty.
boolean	isDefined() true iff this is some.
static <U> Function1B<Option<U>>	isDefinedF() Delegate to isDefined().
static <U> Function1B<Option<U>>	isDefinedP() Deprecated.
abstract boolean	isEmpty() true iff this is none.
static <U> Function1B<Option<U>>	isEmptyF() Delegate to isEmpty().
static <U> Function1B<Option<U>>	isEmptyP() Deprecated.
<U> Option<U>	map(Function<? super T,U> f) Map
static <T> Option<T>	none() Return singleton none object.
static <T> Option<T>	notNull(T x) Some if not null, None otherwise.
static <T> Function<T,Option<T>>	notNullF() Delegate to notNull(Object).
static <T> Function<T,Option<T>>	notNullM() Deprecated.
Option<T>	orElse(Function0<Option<T>> elseOption) this if this is some, or evaluate function and return option otherwise.
Option<T>	orElse(Option<T> elseOption) this if this is some, or given option otherwise.
int	size()
static <T> Option<T>	some(T x) Construct some containing given value.
SetF<T>	toSet()
<F> Option<F>	uncheckedCast() This object with different type parameters
SetF<T>	unique() Return set of elements of this

Methods inherited from class ru.yandex.bolts.collection.impl.AbstractListF

add, add, addAll, clear, collect, drop, emptyCollection, emptyList, equals, filter2, first, firstO, hashCode, honestPlus, indexOf, iterator, last, lastIndexOf, lastO, length, listIterator, listIterator, newMutableCollection, plus, plus, plus, plus, plus1, readOnlyIterator, readOnlyListIterator, remove, removeRange, reverse, reverseIterator, set, subList, take, toList, unmodifiable, zip, zipWithIndex

Methods inherited from class ru.yandex.bolts.collection.impl.AbstractCollectionF

addAll, addF, addOp, containsF, containsP, eq, equals, exists, find, foldLeft, foldRight, forAll, forEach, groupBy, max, max, min, min, mkString, mkString, reduceLeft, reduceRight, single, singleO, singletonCollection, sort, sort, sortBy, sortByDesc, toArray, toBooleanArray, toByteArray, toCharArray, toDoubleArray, toFloatArray, toIntArray, toLongArray, toMap, toMapMappingToKey, toMapMappingToValue, toShortArray

Methods inherited from class java.util.AbstractCollection

addAll, contains, containsAll, remove, removeAll, retainAll, toArray, toArray, toString

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Methods inherited from interface ru.yandex.bolts.collection.CollectionF

addAll, addF, addOp, containsF, containsP, groupBy, max, max, min, min, single, singleO, sort, sort, sortBy, sortByDesc, toArray, toBooleanArray, toByteArray, toCharArray, toDoubleArray, toFloatArray, toIntArray, toLongArray, toMap, toMapMappingToKey, toMapMappingToValue, toShortArray

Methods inherited from interface ru.yandex.bolts.collection.IterableF

exists, find, foldLeft, foldRight, forAll, forEach, mkString, mkString, reduceLeft, reduceRight

Methods inherited from interface java.util.List

addAll, contains, containsAll, remove, removeAll, retainAll, toArray, toArray

Method Detail

isEmpty

public abstract boolean isEmpty()

true iff this is none.

Specified by:

isEmpty in interface Collection<T>

Specified by:

isEmpty in interface List<T>

Overrides:

isEmpty in class AbstractCollection<T>

isDefined

public final boolean isDefined()

true iff this is some.

get

public abstract T get()
               throws NoSuchElementException

Get the value.

Throws:

NoSuchElementException - if this is none.

getOrElse

public final T getOrElse(T u)

If this is some return value of this, or return given value otherwise.

getOrElse

public final T getOrElse(Function0<T> u)

If this is some return value of this, or evaluate function and return it value otherwise.

getOrNull

public final T getOrNull()

getOrElse(null), but works with types better.

orElse

public final Option<T> orElse(Option<T> elseOption)

this if this is some, or given option otherwise.

orElse

public final Option<T> orElse(Function0<Option<T>> elseOption)

this if this is some, or evaluate function and return option otherwise.

getOrThrow

public final <E extends Throwable> T getOrThrow(E e)
                   throws E extends Throwable

Throw specified exception if isEmpty().

Throws:

E extends Throwable

getOrThrow

public final <E extends Throwable> T getOrThrow(Function0<E> e)
                   throws E extends Throwable

Throw specified exception if isEmpty().

Throws:

E extends Throwable

getOrThrow

public final T getOrThrow(String message)
                   throws RuntimeException

Throw exception with specified message if this is empty

Throws:

RuntimeException

getOrThrow

public final T getOrThrow(String message,
                          Object param)
                   throws RuntimeException

Get or throw exception if this is empty. Message is constructed by concatenating given params.

Throws:

RuntimeException

size

public int size()

Specified by:

size in interface Collection<T>

Specified by:

size in interface List<T>

Specified by:

size in class AbstractCollection<T>

get

public T get(int index)

Description copied from class: AbstractListF

Answers the element at the specified location in this List.

Specified by:

get in interface List<T>

Specified by:

get in class AbstractListF<T>

Parameters:

index - the index of the element to return

Returns:

the element at the specified index

map

public final <U> Option<U> map(Function<? super T,U> f)

Description copied from interface: CollectionF

Map

Specified by:

map in interface CollectionF<T>

Overrides:

map in class AbstractCollectionF<T>

flatMapO

public final <U> Option<U> flatMapO(Function<? super T,Option<U>> f)

Description copied from interface: CollectionF

Flat map variant that accept mapper that returns Option instead of Collection

Specified by:

flatMapO in interface CollectionF<T>

Overrides:

flatMapO in class AbstractCollectionF<T>

flatMap

public <B> ListF<B> flatMap(Function<? super T,? extends Collection<B>> f)

Description copied from interface: CollectionF

Flat map

Specified by:

flatMap in interface CollectionF<T>

Overrides:

flatMap in class AbstractCollectionF<T>

filter

public final Option<T> filter(Function1B<? super T> p)

Description copied from interface: CollectionF

Return collection with only elements that match predicate.

Specified by:

filter in interface CollectionF<T>

Specified by:

filter in interface ListF<T>

Overrides:

filter in class AbstractListF<T>

toSet

public final SetF<T> toSet()

unique

public SetF<T> unique()

Description copied from interface: CollectionF

Return set of elements of this

Specified by:

unique in interface CollectionF<T>

Overrides:

unique in class AbstractCollectionF<T>

uncheckedCast

public <F> Option<F> uncheckedCast()

This object with different type parameters

Specified by:

uncheckedCast in interface CollectionF<T>

Specified by:

uncheckedCast in interface IterableF<T>

Specified by:

uncheckedCast in interface ListF<T>

Overrides:

uncheckedCast in class AbstractListF<T>

none

public static <T> Option<T> none()

Return singleton none object.

some

public static <T> Option<T> some(T x)

Construct some containing given value.

notNull

public static <T> Option<T> notNull(T x)

Some if not null, None otherwise.

isDefinedP

public static <U> Function1B<Option<U>> isDefinedP()

Deprecated.

isDefinedF

public static <U> Function1B<Option<U>> isDefinedF()

Delegate to isDefined().

isEmptyP

public static <U> Function1B<Option<U>> isEmptyP()

Deprecated.

isEmptyF

public static <U> Function1B<Option<U>> isEmptyF()

Delegate to isEmpty().

notNullM

public static <T> Function<T,Option<T>> notNullM()

Deprecated.

notNullF

public static <T> Function<T,Option<T>> notNullF()

Delegate to notNull(Object).

getM

public static <U> Function<Option<U>,U> getM()

Deprecated.

getF

public static <U> Function<Option<U>,U> getF()

Delegate to get().