Class ImmutableEmptySet<T>

java.lang.Object

org.eclipse.collections.impl.AbstractRichIterable<T>

org.eclipse.collections.impl.collection.immutable.AbstractImmutableCollection<T>

org.eclipse.collections.impl.set.immutable.AbstractImmutableSet<T>

org.eclipse.collections.impl.set.immutable.ImmutableEmptySet<T>

All Implemented Interfaces:

Serializable, Iterable<T>, Collection<T>, Set<T>, ImmutableCollection<T>, InternalIterable<T>, RichIterable<T>, ImmutableSet<T>, ImmutableSetIterable<T>, SetIterable<T>, UnsortedSetIterable<T>

final class ImmutableEmptySet<T>
extends AbstractImmutableSet<T>
implements Serializable

This is a zero element ImmutableSet which is created by calling the Sets.immutable.empty() method.

Nested Class Summary

Nested classes/interfaces inherited from class AbstractImmutableSet

AbstractImmutableSet.ImmutableSetIterator

Field Summary

Fields

Modifier and Type	Field	Description
private static final PartitionImmutableSet<?>	EMPTY
(package private) static final ImmutableSet<?>	INSTANCE
private static final long	serialVersionUID

Constructor Summary

Constructors

Constructor	Description
ImmutableEmptySet()

Method Summary

Modifier and Type	Method	Description
boolean	allSatisfy(Predicate<? super T> predicate)	Returns true if the predicate evaluates to true for every element of the iterable or if the iterable is empty.
<P> boolean	allSatisfyWith(Predicate2<? super T, ? super P> predicate, P parameter)	Returns true if the predicate evaluates to true for every element of the collection, or returns false.
boolean	anySatisfy(Predicate<? super T> predicate)	Returns true if the predicate evaluates to true for any element of the iterable.
<P> boolean	anySatisfyWith(Predicate2<? super T, ? super P> predicate, P parameter)	Returns true if the predicate evaluates to true for any element of the collection, or return false.
void	appendString(Appendable appendable)	Prints a string representation of this collection onto the given Appendable.
void	appendString(Appendable appendable, String separator)	Prints a string representation of this collection onto the given Appendable.
void	appendString(Appendable appendable, String start, String separator, String end)	Prints a string representation of this collection onto the given Appendable.
<V> ImmutableSet<V>	collect(Function<? super T, ? extends V> function)	Returns a new collection with the results of applying the specified function on each element of the source collection.
<V, R extends Collection<V>> R	collect(Function<? super T, ? extends V> function, R target)	Same as RichIterable.collect(Function), except that the results are gathered into the specified target collection.
<V> ImmutableSet<V>	collectIf(Predicate<? super T> predicate, Function<? super T, ? extends V> function)	Returns a new collection with the results of applying the specified function on each element of the source collection, but only for those elements which return true upon evaluation of the predicate.
<V, R extends Collection<V>> R	collectIf(Predicate<? super T> predicate, Function<? super T, ? extends V> function, R target)	Same as the collectIf method with two parameters but uses the specified target collection for the results.
<P, V, R extends Collection<V>> R	collectWith(Function2<? super T, ? super P, ? extends V> function, P parameter, R target)	Same as collectWith but with a targetCollection parameter to gather the results.
boolean	contains(Object obj)	Returns true if the iterable has an element which responds true to element.equals(object).
int	count(Predicate<? super T> predicate)	Return the total number of elements that answer true to the specified predicate.
<V> ImmutableBag<V>	countBy(Function<? super T, ? extends V> function)	This method will count the number of occurrences of each value calculated by applying the function to each element of the collection.
<V, R extends MutableBagIterable<V>> R	countBy(Function<? super T, ? extends V> function, R target)	This method will count the number of occurrences of each value calculated by applying the function to each element of the collection.
<V> ImmutableBag<V>	countByEach(Function<? super T, ? extends Iterable<V>> function)	This method will count the number of occurrences of each value calculated by applying the function to each element of the collection.
<V, R extends MutableBagIterable<V>> R	countByEach(Function<? super T, ? extends Iterable<V>> function, R target)	This method will count the number of occurrences of each value calculated by applying the function to each element of the collection.
<V,P> ImmutableBag<V>	countByWith(Function2<? super T, ? super P, ? extends V> function, P parameter)	This method will count the number of occurrences of each value calculated by applying the function to each element of the collection with the specified parameter as the second argument.
<V, P, R extends MutableBagIterable<V>> R	countByWith(Function2<? super T, ? super P, ? extends V> function, P parameter, R target)	This method will count the number of occurrences of each value calculated by applying the function to each element of the collection with the specified parameter as the second argument.
<P> int	countWith(Predicate2<? super T, ? super P> predicate, P parameter)	Returns the total number of elements that evaluate to true for the specified predicate.
T	detect(Predicate<? super T> predicate)	Returns the first element of the iterable for which the predicate evaluates to true or null in the case where no element returns true.
T	detectIfNone(Predicate<? super T> predicate, Function0<? extends T> function)	Returns the first element of the iterable for which the predicate evaluates to true.
Optional<T>	detectOptional(Predicate<? super T> predicate)	Returns the first element of the iterable for which the predicate evaluates to true as an Optional.
void	each(Procedure<? super T> procedure)	The procedure is executed for each element in the iterable.
boolean	equals(Object other)	Follows the same general contract as Set.equals(Object).
<V> ImmutableSet<V>	flatCollect(Function<? super T, ? extends Iterable<V>> function)	flatCollect is a special case of RichIterable.collect(Function).
<V, R extends Collection<V>> R	flatCollect(Function<? super T, ? extends Iterable<V>> function, R target)	Same as flatCollect, only the results are collected into the target collection.
<P> void	forEachWith(Procedure2<? super T, ? super P> procedure, P parameter)	The procedure2 is evaluated for each element in the iterable with the specified parameter provided as the second argument.
void	forEachWithIndex(ObjectIntProcedure<? super T> objectIntProcedure)	Iterates over the iterable passing each element and the current relative int index to the specified instance of ObjectIntProcedure.
T	getFirst()	Returns the first element of an iterable.
T	getLast()	Returns the last element of an iterable.
T	getOnly()	Returns the element if the iterable has exactly one element.
<V, R extends MutableMultimap<V,T>> R	groupBy(Function<? super T, ? extends V> function, R target)	Same as RichIterable.groupBy(Function), except that the results are gathered into the specified target multimap.
<V, R extends MutableMultimap<V,T>> R	groupByEach(Function<? super T, ? extends Iterable<V>> function, R target)	Same as RichIterable.groupByEach(Function), except that the results are gathered into the specified target multimap.
int	hashCode()	Follows the same general contract as Set.hashCode().
double	injectInto(double injectedValue, DoubleObjectToDoubleFunction<? super T> doubleObjectToDoubleFunction)	Returns the final double result of evaluating function using each element of the iterable and the previous evaluation result as the parameters.
int	injectInto(int injectedValue, IntObjectToIntFunction<? super T> intObjectToIntFunction)	Returns the final int result of evaluating function using each element of the iterable and the previous evaluation result as the parameters.
long	injectInto(long injectedValue, LongObjectToLongFunction<? super T> longObjectToLongFunction)	Returns the final long result of evaluating function using each element of the iterable and the previous evaluation result as the parameters.
<IV> IV	injectInto(IV injectedValue, Function2<? super IV, ? super T, ? extends IV> function)	Returns the final result of evaluating function using each element of the iterable and the previous evaluation result as the parameters.
boolean	isEmpty()	Returns true if this iterable has zero items.
Iterator<T>	iterator()
String	makeString()	Returns a string representation of this collection by delegating to RichIterable.makeString(String) and defaulting the separator parameter to the characters ", " (comma and space).
String	makeString(String separator)	Returns a string representation of this collection by delegating to RichIterable.makeString(String, String, String) and defaulting the start and end parameters to "" (the empty String).
String	makeString(String start, String separator, String end)	Returns a string representation of this collection with the elements separated by the specified separator and enclosed between the start and end strings.
T	max()	Returns the maximum element out of this container based on the natural order.
T	max(Comparator<? super T> comparator)	Returns the maximum element out of this container based on the comparator.
<V extends Comparable<? super V>> T	maxBy(Function<? super T, ? extends V> function)	Returns the maximum elements out of this container based on the natural order of the attribute returned by Function.
T	min()	Returns the minimum element out of this container based on the natural order.
T	min(Comparator<? super T> comparator)	Returns the minimum element out of this container based on the comparator.
<V extends Comparable<? super V>> T	minBy(Function<? super T, ? extends V> function)	Returns the minimum elements out of this container based on the natural order of the attribute returned by Function.
ImmutableSet<T>	newWith(T element)	This method is similar to the with method in MutableCollection with the difference that a new copy of this collection with the element appended will be returned.
ImmutableSet<T>	newWithAll(Iterable<? extends T> elements)	This method is similar to the withAll method in MutableCollection with the difference that a new copy of this collection with the elements appended will be returned.
ImmutableSet<T>	newWithout(T element)	This method is similar to the without method in MutableCollection with the difference that a new copy of this collection with the element removed will be returned.
ImmutableSet<T>	newWithoutAll(Iterable<? extends T> elements)	This method is similar to the withoutAll method in MutableCollection with the difference that a new copy of this collection with the elements removed will be returned.
boolean	noneSatisfy(Predicate<? super T> predicate)	Returns true if the predicate evaluates to false for every element of the iterable or if the iterable is empty.
<P> boolean	noneSatisfyWith(Predicate2<? super T, ? super P> predicate, P parameter)	Returns true if the predicate evaluates to false for every element of the collection, or return false.
boolean	notEmpty()	The English equivalent of !this.isEmpty()
PartitionImmutableSet<T>	partition(Predicate<? super T> predicate)	Filters a collection into a PartitionedIterable based on the evaluation of the predicate.
ImmutableSet<T>	reject(Predicate<? super T> predicate)	Returns all elements of the source collection that return false when evaluating of the predicate.
<R extends Collection<T>> R	reject(Predicate<? super T> predicate, R target)	Same as the reject method with one parameter but uses the specified target collection for the results.
<P, R extends Collection<T>> R	rejectWith(Predicate2<? super T, ? super P> predicate, P parameter, R target)	Similar to RichIterable.reject(Predicate, Collection), except with an evaluation parameter for the second generic argument in Predicate2.
ImmutableSet<T>	select(Predicate<? super T> predicate)	Returns all elements of the source collection that return true when evaluating the predicate.
<R extends Collection<T>> R	select(Predicate<? super T> predicate, R target)	Same as the select method with one parameter but uses the specified target collection for the results.
<P, R extends Collection<T>> R	selectWith(Predicate2<? super T, ? super P> predicate, P parameter, R target)	Similar to RichIterable.select(Predicate, Collection), except with an evaluation parameter for the second generic argument in Predicate2.
int	size()	Returns the number of items in this iterable.
ImmutableSet<T>	tap(Procedure<? super T> procedure)	Executes the Procedure for each element in the iterable and returns this.
String	toString()	Returns a string with the elements of the iterable separated by commas with spaces and enclosed in square brackets.
private Object	writeReplace()
<S> ImmutableSet<Pair<T,S>>	zip(Iterable<S> that)	Deprecated. in 6.0.
<S, R extends Collection<Pair<T,S>>> R	zip(Iterable<S> that, R target)	Same as RichIterable.zip(Iterable) but uses target for output.
ImmutableSet<Pair<T,Integer>>	zipWithIndex()	Deprecated. in 6.0.
<R extends Collection<Pair<T,Integer>>> R	zipWithIndex(R target)	Same as RichIterable.zipWithIndex() but uses target for output.

Methods inherited from class AbstractImmutableSet

asParallel, cartesianProduct, castToSet, collectBoolean, collectByte, collectChar, collectDouble, collectFloat, collectInt, collectLong, collectShort, collectWith, difference, differenceInto, groupBy, groupByEach, intersect, intersectInto, isProperSubsetOf, isSubsetOf, newMutable, nullSafeHashCode, partitionWith, powerSet, rejectWith, selectInstancesOf, selectWith, symmetricDifference, symmetricDifferenceInto, toImmutable, union, unionInto

Methods inherited from class AbstractImmutableCollection

add, addAll, castToCollection, chunk, clear, groupByUniqueKey, parallelStream, reduce, remove, removeAll, removeAllFrom, retainAll, spliterator, stream, sumByDouble, sumByFloat, sumByInt, sumByLong, toArray, toArray

Methods inherited from class AbstractRichIterable

asLazy, containsAll, containsAllArguments, containsAllIterable, detectWith, detectWithIfNone, detectWithOptional, forEach, groupByUniqueKey, injectInto, into, sumOfDouble, sumOfFloat, sumOfInt, sumOfLong, toBag, toBiMap, toList, toMap, toSet, toSortedBag, toSortedBag, toSortedBagBy, toSortedListBy, toSortedMap, toSortedMap, toSortedMapBy, toSortedSet, toSortedSet, toSortedSetBy

Methods inherited from class Object

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

Methods inherited from interface Collection

parallelStream, removeIf, stream, toArray

Methods inherited from interface ImmutableCollection

aggregateBy, aggregateInPlaceBy, castToCollection, flatCollectWith, groupByUniqueKey, parallelStream, reduceBy, spliterator, stream, sumByDouble, sumByFloat, sumByInt, sumByLong

Methods inherited from interface ImmutableSet

flatCollectWith, toImmutableSet

Methods inherited from interface InternalIterable

forEach

Methods inherited from interface RichIterable

aggregateBy, asLazy, chunk, collectBoolean, collectByte, collectChar, collectDouble, collectFloat, collectInt, collectLong, collectShort, containsAll, containsAllArguments, containsAllIterable, containsAny, containsAnyIterable, containsBy, containsNone, containsNoneIterable, detectWith, detectWithIfNone, detectWithOptional, flatCollectBoolean, flatCollectByte, flatCollectChar, flatCollectDouble, flatCollectFloat, flatCollectInt, flatCollectLong, flatCollectShort, flatCollectWith, forEach, getAny, groupByAndCollect, groupByUniqueKey, injectInto, injectIntoDouble, injectIntoFloat, injectIntoInt, injectIntoLong, into, makeString, maxByOptional, maxOptional, maxOptional, minByOptional, minOptional, minOptional, reduce, reduceBy, reduceInPlace, reduceInPlace, summarizeDouble, summarizeFloat, summarizeInt, summarizeLong, sumOfDouble, sumOfFloat, sumOfInt, sumOfLong, toArray, toArray, toBag, toBiMap, toImmutableBag, toImmutableBiMap, toImmutableList, toImmutableMap, toImmutableSortedBag, toImmutableSortedBag, toImmutableSortedBagBy, toImmutableSortedList, toImmutableSortedList, toImmutableSortedListBy, toImmutableSortedSet, toImmutableSortedSet, toImmutableSortedSetBy, toList, toMap, toMap, toSet, toSortedBag, toSortedBag, toSortedBagBy, toSortedList, toSortedList, toSortedListBy, toSortedMap, toSortedMap, toSortedMapBy, toSortedSet, toSortedSet, toSortedSetBy

Methods inherited from interface Set

add, addAll, clear, containsAll, remove, removeAll, retainAll, spliterator, toArray, toArray

Field Details

INSTANCE

static final ImmutableSet<?> INSTANCE

EMPTY

private static final PartitionImmutableSet<?> EMPTY

serialVersionUID

private static final long serialVersionUID

See Also:

• Constant Field Values

Constructor Details

ImmutableEmptySet

ImmutableEmptySet()

Method Details

equals

public boolean equals(Object other)

Description copied from interface: SetIterable

Follows the same general contract as Set.equals(Object).

Specified by:

equals in interface Collection<T>

Specified by:

equals in interface Set<T>

Specified by:

equals in interface SetIterable<T>

Overrides:

equals in class Object

hashCode

public int hashCode()

Description copied from interface: SetIterable

Follows the same general contract as Set.hashCode().

Specified by:

hashCode in interface Collection<T>

Specified by:

hashCode in interface Set<T>

Specified by:

hashCode in interface SetIterable<T>

Overrides:

hashCode in class Object

newWith

public ImmutableSet<T> newWith(T element)

Description copied from interface: ImmutableCollection

This method is similar to the with method in MutableCollection with the difference that a new copy of this collection with the element appended will be returned.

Specified by:

newWith in interface ImmutableCollection<T>

Specified by:

newWith in interface ImmutableSet<T>

Overrides:

newWith in class AbstractImmutableSet<T>

newWithAll

public ImmutableSet<T> newWithAll(Iterable<? extends T> elements)

Description copied from interface: ImmutableCollection

This method is similar to the withAll method in MutableCollection with the difference that a new copy of this collection with the elements appended will be returned.

Specified by:

newWithAll in interface ImmutableCollection<T>

Specified by:

newWithAll in interface ImmutableSet<T>

Overrides:

newWithAll in class AbstractImmutableSet<T>

newWithout

public ImmutableSet<T> newWithout(T element)

Description copied from interface: ImmutableCollection

This method is similar to the without method in MutableCollection with the difference that a new copy of this collection with the element removed will be returned.

Specified by:

newWithout in interface ImmutableCollection<T>

Specified by:

newWithout in interface ImmutableSet<T>

Overrides:

newWithout in class AbstractImmutableSet<T>

newWithoutAll

public ImmutableSet<T> newWithoutAll(Iterable<? extends T> elements)

Description copied from interface: ImmutableCollection

This method is similar to the withoutAll method in MutableCollection with the difference that a new copy of this collection with the elements removed will be returned.

Specified by:

newWithoutAll in interface ImmutableCollection<T>

Specified by:

newWithoutAll in interface ImmutableSet<T>

Overrides:

newWithoutAll in class AbstractImmutableSet<T>

size

public int size()

Description copied from interface: RichIterable

Returns the number of items in this iterable.

Specified by:

size in interface Collection<T>

Specified by:

size in interface RichIterable<T>

Specified by:

size in interface Set<T>

contains

public boolean contains(Object obj)

Description copied from interface: RichIterable

Returns true if the iterable has an element which responds true to element.equals(object).

Specified by:

contains in interface Collection<T>

Specified by:

contains in interface RichIterable<T>

Specified by:

contains in interface Set<T>

Overrides:

contains in class AbstractRichIterable<T>

tap

public ImmutableSet<T> tap(Procedure<? super T> procedure)

Description copied from interface: RichIterable

Executes the Procedure for each element in the iterable and returns this.

Example using a Java 8 lambda expression:

RichIterable<Person> tapped =
    people.tap(person -> LOGGER.info(person.getName()));

Specified by:

tap in interface ImmutableCollection<T>

Specified by:

tap in interface ImmutableSet<T>

Specified by:

tap in interface ImmutableSetIterable<T>

Specified by:

tap in interface RichIterable<T>

Specified by:

tap in interface SetIterable<T>

Specified by:

tap in interface UnsortedSetIterable<T>

Overrides:

tap in class AbstractImmutableSet<T>

See Also:

• RichIterable.each(Procedure)
• RichIterable.forEach(Procedure)

each

public void each(Procedure<? super T> procedure)

Description copied from interface: RichIterable

The procedure is executed for each element in the iterable.

Example using a Java 8 lambda expression:

people.each(person -> LOGGER.info(person.getName()));

This method is a variant of InternalIterable.forEach(Procedure) that has a signature conflict with Iterable.forEach(java.util.function.Consumer).

Specified by:

each in interface RichIterable<T>

See Also:

• InternalIterable.forEach(Procedure)
• Iterable.forEach(java.util.function.Consumer)

forEachWithIndex

public void forEachWithIndex(ObjectIntProcedure<? super T> objectIntProcedure)

Description copied from interface: InternalIterable

Iterates over the iterable passing each element and the current relative int index to the specified instance of ObjectIntProcedure.

Example using a Java 8 lambda:

people.forEachWithIndex((Person person, int index) -> LOGGER.info("Index: " + index + " person: " + person.getName()));

Example using an anonymous inner class:

people.forEachWithIndex(new ObjectIntProcedure<Person>()
{
    public void value(Person person, int index)
    {
        LOGGER.info("Index: " + index + " person: " + person.getName());
    }
});

Specified by:

forEachWithIndex in interface InternalIterable<T>

Overrides:

forEachWithIndex in class AbstractRichIterable<T>

forEachWith

public <P> void forEachWith(Procedure2<? super T, ? super P> procedure,
 P parameter)

Description copied from interface: InternalIterable

The procedure2 is evaluated for each element in the iterable with the specified parameter provided as the second argument.

Example using a Java 8 lambda:

people.forEachWith((Person person, Person other) ->
    {
        if (person.isRelatedTo(other))
        {
             LOGGER.info(person.getName());
        }
    }, fred);

Example using an anonymous inner class:

people.forEachWith(new Procedure2<Person, Person>()
{
    public void value(Person person, Person other)
    {
        if (person.isRelatedTo(other))
        {
             LOGGER.info(person.getName());
        }
    }
}, fred);

Specified by:

forEachWith in interface InternalIterable<T>

Overrides:

forEachWith in class AbstractRichIterable<T>

getFirst

public T getFirst()

Description copied from interface: RichIterable

Returns the first element of an iterable. In the case of a List it is the element at the first index. In the case of any other Collection, it is the first element that would be returned during an iteration. If the iterable is empty, null is returned. If null is a valid element of the container, then a developer would need to check to see if the iterable is empty to validate that a null result was not due to the container being empty.

The order of Sets are not guaranteed (except for TreeSets and other Ordered Set implementations), so if you use this method, the first element could be any element from the Set.

Specified by:

getFirst in interface RichIterable<T>

getLast

public T getLast()

Description copied from interface: RichIterable

Returns the last element of an iterable. In the case of a List it is the element at the last index. In the case of any other Collection, it is the last element that would be returned during an iteration. If the iterable is empty, null is returned. If null is a valid element of the container, then a developer would need to check to see if the iterable is empty to validate that a null result was not due to the container being empty.

The order of Sets are not guaranteed (except for TreeSets and other Ordered Set implementations), so if you use this method, the last element could be any element from the Set.

Specified by:

getLast in interface RichIterable<T>

getOnly

public T getOnly()

Description copied from interface: RichIterable

Returns the element if the iterable has exactly one element. Otherwise, throw IllegalStateException.

Specified by:

getOnly in interface RichIterable<T>

Returns:

an element of an iterable.

iterator

public Iterator<T> iterator()

Specified by:

iterator in interface Collection<T>

Specified by:

iterator in interface Iterable<T>

Specified by:

iterator in interface Set<T>

min

public T min(Comparator<? super T> comparator)

Description copied from interface: RichIterable

Returns the minimum element out of this container based on the comparator.

Specified by:

min in interface RichIterable<T>

Overrides:

min in class AbstractRichIterable<T>

max

public T max(Comparator<? super T> comparator)

Description copied from interface: RichIterable

Returns the maximum element out of this container based on the comparator.

Specified by:

max in interface RichIterable<T>

Overrides:

max in class AbstractRichIterable<T>

min

public T min()

Description copied from interface: RichIterable

Returns the minimum element out of this container based on the natural order.

Specified by:

min in interface RichIterable<T>

Overrides:

min in class AbstractRichIterable<T>

max

public T max()

Description copied from interface: RichIterable

Returns the maximum element out of this container based on the natural order.

Specified by:

max in interface RichIterable<T>

Overrides:

max in class AbstractRichIterable<T>

minBy

public <V extends Comparable<? super V>> T minBy(Function<? super T, ? extends V> function)

Description copied from interface: RichIterable

Returns the minimum elements out of this container based on the natural order of the attribute returned by Function.

Specified by:

minBy in interface RichIterable<T>

Overrides:

minBy in class AbstractRichIterable<T>

maxBy

public <V extends Comparable<? super V>> T maxBy(Function<? super T, ? extends V> function)

Description copied from interface: RichIterable

Returns the maximum elements out of this container based on the natural order of the attribute returned by Function.

Specified by:

maxBy in interface RichIterable<T>

Overrides:

maxBy in class AbstractRichIterable<T>

zip

@Deprecated
public <S> ImmutableSet<Pair<T,S>> zip(Iterable<S> that)

Deprecated.

in 6.0. Use OrderedIterable.zip(Iterable) instead.

Description copied from interface: RichIterable

Returns a RichIterable formed from this RichIterable and another RichIterable by combining corresponding elements in pairs. If one of the two RichIterables is longer than the other, its remaining elements are ignored.

Specified by:

zip in interface ImmutableCollection<T>

Specified by:

zip in interface ImmutableSet<T>

Specified by:

zip in interface RichIterable<T>

Specified by:

zip in interface UnsortedSetIterable<T>

Overrides:

zip in class AbstractImmutableSet<T>

Type Parameters:

S - the type of the second half of the returned pairs

Parameters:

that - The RichIterable providing the second half of each result pair

Returns:

A new RichIterable containing pairs consisting of corresponding elements of this RichIterable and that. The length of the returned RichIterable is the minimum of the lengths of this RichIterable and that.

zip

public <S, R extends Collection<Pair<T,S>>> R zip(Iterable<S> that,
 R target)

Description copied from interface: RichIterable

Same as RichIterable.zip(Iterable) but uses target for output.

Specified by:

zip in interface RichIterable<T>

Overrides:

zip in class AbstractRichIterable<T>

zipWithIndex

@Deprecated
public ImmutableSet<Pair<T,Integer>> zipWithIndex()

Deprecated.

in 6.0. Use OrderedIterable.zipWithIndex() instead.

Description copied from interface: RichIterable

Zips this RichIterable with its indices.

Specified by:

zipWithIndex in interface ImmutableCollection<T>

Specified by:

zipWithIndex in interface ImmutableSet<T>

Specified by:

zipWithIndex in interface ImmutableSetIterable<T>

Specified by:

zipWithIndex in interface RichIterable<T>

Specified by:

zipWithIndex in interface SetIterable<T>

Specified by:

zipWithIndex in interface UnsortedSetIterable<T>

Overrides:

zipWithIndex in class AbstractImmutableSet<T>

Returns:

A new RichIterable containing pairs consisting of all elements of this RichIterable paired with their index. Indices start at 0.

See Also:

• RichIterable.zip(Iterable)

zipWithIndex

public <R extends Collection<Pair<T,Integer>>> R zipWithIndex(R target)

Description copied from interface: RichIterable

Same as RichIterable.zipWithIndex() but uses target for output.

Specified by:

zipWithIndex in interface RichIterable<T>

Overrides:

zipWithIndex in class AbstractRichIterable<T>

select

public ImmutableSet<T> select(Predicate<? super T> predicate)

Description copied from interface: RichIterable

Returns all elements of the source collection that return true when evaluating the predicate. This method is also commonly called filter.

Example using a Java 8 lambda expression:

RichIterable<Person> selected =
    people.select(person -> person.getAddress().getCity().equals("London"));

Specified by:

select in interface ImmutableCollection<T>

Specified by:

select in interface ImmutableSet<T>

Specified by:

select in interface ImmutableSetIterable<T>

Specified by:

select in interface RichIterable<T>

Specified by:

select in interface SetIterable<T>

Specified by:

select in interface UnsortedSetIterable<T>

Overrides:

select in class AbstractImmutableSet<T>

reject

public ImmutableSet<T> reject(Predicate<? super T> predicate)

Description copied from interface: RichIterable

Returns all elements of the source collection that return false when evaluating of the predicate. This method is also sometimes called filterNot and is the equivalent of calling iterable.select(Predicates.not(predicate)).

Example using a Java 8 lambda expression:

RichIterable<Person> rejected =
    people.reject(person -> person.person.getLastName().equals("Smith"));

Specified by:

reject in interface ImmutableCollection<T>

Specified by:

reject in interface ImmutableSet<T>

Specified by:

reject in interface ImmutableSetIterable<T>

Specified by:

reject in interface RichIterable<T>

Specified by:

reject in interface SetIterable<T>

Specified by:

reject in interface UnsortedSetIterable<T>

Overrides:

reject in class AbstractImmutableSet<T>

Parameters:

predicate - a Predicate to use as the reject criteria

Returns:

a RichIterable that contains elements that cause Predicate.accept(Object) method to evaluate to false

partition

public PartitionImmutableSet<T> partition(Predicate<? super T> predicate)

Description copied from interface: RichIterable

Filters a collection into a PartitionedIterable based on the evaluation of the predicate.

Example using a Java 8 lambda expression:

PartitionIterable<Person> newYorkersAndNonNewYorkers =
    people.partition(person -> person.getAddress().getState().getName().equals("New York"));

Specified by:

partition in interface ImmutableCollection<T>

Specified by:

partition in interface ImmutableSet<T>

Specified by:

partition in interface ImmutableSetIterable<T>

Specified by:

partition in interface RichIterable<T>

Specified by:

partition in interface SetIterable<T>

Overrides:

partition in class AbstractImmutableSet<T>

collect

public <V> ImmutableSet<V> collect(Function<? super T, ? extends V> function)

Description copied from interface: RichIterable

Returns a new collection with the results of applying the specified function on each element of the source collection. This method is also commonly called transform or map.

Example using a Java 8 lambda expression:

RichIterable<String> names =
    people.collect(person -> person.getFirstName() + " " + person.getLastName());

Specified by:

collect in interface ImmutableCollection<T>

Specified by:

collect in interface ImmutableSet<T>

Specified by:

collect in interface RichIterable<T>

Specified by:

collect in interface UnsortedSetIterable<T>

Overrides:

collect in class AbstractImmutableSet<T>

collectIf

public <V> ImmutableSet<V> collectIf(Predicate<? super T> predicate,
 Function<? super T, ? extends V> function)

Description copied from interface: RichIterable

Returns a new collection with the results of applying the specified function on each element of the source collection, but only for those elements which return true upon evaluation of the predicate. This is the optimized equivalent of calling iterable.select(predicate).collect(function).

Example using a Java 8 lambda and method reference:

RichIterable<String> strings = Lists.mutable.with(1, 2, 3).collectIf(e -> e != null, Object::toString);

Example using Predicates factory:

RichIterable<String> strings = Lists.mutable.with(1, 2, 3).collectIf(Predicates.notNull(), Functions.getToString());

Specified by:

collectIf in interface ImmutableCollection<T>

Specified by:

collectIf in interface ImmutableSet<T>

Specified by:

collectIf in interface RichIterable<T>

Specified by:

collectIf in interface UnsortedSetIterable<T>

Overrides:

collectIf in class AbstractImmutableSet<T>

flatCollect

public <V> ImmutableSet<V> flatCollect(Function<? super T, ? extends Iterable<V>> function)

Description copied from interface: RichIterable

flatCollect is a special case of RichIterable.collect(Function). With collect, when the Function returns a collection, the result is a collection of collections. flatCollect outputs a single "flattened" collection instead. This method is commonly called flatMap.

Consider the following example where we have a Person class, and each Person has a list of Address objects. Take the following Function:

Function<Person, List<Address>> addressFunction = Person::getAddresses;
RichIterable<Person> people = ...;

Using collect returns a collection of collections of addresses.

RichIterable<List<Address>> addresses = people.collect(addressFunction);

Using flatCollect returns a single flattened list of addresses.

RichIterable<Address> addresses = people.flatCollect(addressFunction);

Specified by:

flatCollect in interface ImmutableCollection<T>

Specified by:

flatCollect in interface ImmutableSet<T>

Specified by:

flatCollect in interface RichIterable<T>

Specified by:

flatCollect in interface UnsortedSetIterable<T>

Overrides:

flatCollect in class AbstractImmutableSet<T>

Parameters:

function - The Function to apply

Returns:

a new flattened collection produced by applying the given function

countBy

public <V> ImmutableBag<V> countBy(Function<? super T, ? extends V> function)

Description copied from interface: RichIterable

This method will count the number of occurrences of each value calculated by applying the function to each element of the collection.

Specified by:

countBy in interface ImmutableCollection<T>

Specified by:

countBy in interface RichIterable<T>

Overrides:

countBy in class AbstractImmutableCollection<T>

Since:

9.0

countBy

public <V, R extends MutableBagIterable<V>> R countBy(Function<? super T, ? extends V> function,
 R target)

Description copied from interface: RichIterable

This method will count the number of occurrences of each value calculated by applying the function to each element of the collection.

Specified by:

countBy in interface RichIterable<T>

Since:

9.0

countByWith

public <V,P> ImmutableBag<V> countByWith(Function2<? super T, ? super P, ? extends V> function,
 P parameter)

Description copied from interface: RichIterable

This method will count the number of occurrences of each value calculated by applying the function to each element of the collection with the specified parameter as the second argument.

Specified by:

countByWith in interface ImmutableCollection<T>

Specified by:

countByWith in interface RichIterable<T>

Overrides:

countByWith in class AbstractImmutableCollection<T>

Since:

9.0

countByWith

public <V, P, R extends MutableBagIterable<V>> R countByWith(Function2<? super T, ? super P, ? extends V> function,
 P parameter,
 R target)

Description copied from interface: RichIterable

This method will count the number of occurrences of each value calculated by applying the function to each element of the collection with the specified parameter as the second argument.

Specified by:

countByWith in interface RichIterable<T>

Since:

9.0

countByEach

public <V> ImmutableBag<V> countByEach(Function<? super T, ? extends Iterable<V>> function)

Description copied from interface: RichIterable

This method will count the number of occurrences of each value calculated by applying the function to each element of the collection.

Specified by:

countByEach in interface ImmutableCollection<T>

Specified by:

countByEach in interface RichIterable<T>

Overrides:

countByEach in class AbstractImmutableCollection<T>

Since:

10.0.0

countByEach

public <V, R extends MutableBagIterable<V>> R countByEach(Function<? super T, ? extends Iterable<V>> function,
 R target)

Description copied from interface: RichIterable

This method will count the number of occurrences of each value calculated by applying the function to each element of the collection.

Specified by:

countByEach in interface RichIterable<T>

Since:

10.0.0

groupBy

public <V, R extends MutableMultimap<V,T>> R groupBy(Function<? super T, ? extends V> function,
 R target)

Description copied from interface: RichIterable

Same as RichIterable.groupBy(Function), except that the results are gathered into the specified target multimap.

Example using a Java 8 method reference:

FastListMultimap<String, Person> peopleByLastName =
    people.groupBy(Person::getLastName, new FastListMultimap<String, Person>());

Specified by:

groupBy in interface RichIterable<T>

Overrides:

groupBy in class AbstractImmutableSet<T>

groupByEach

public <V, R extends MutableMultimap<V,T>> R groupByEach(Function<? super T, ? extends Iterable<V>> function,
 R target)

Description copied from interface: RichIterable

Same as RichIterable.groupByEach(Function), except that the results are gathered into the specified target multimap.

Specified by:

groupByEach in interface RichIterable<T>

Overrides:

groupByEach in class AbstractImmutableSet<T>

isEmpty

public boolean isEmpty()

Description copied from interface: RichIterable

Returns true if this iterable has zero items.

Specified by:

isEmpty in interface Collection<T>

Specified by:

isEmpty in interface RichIterable<T>

Specified by:

isEmpty in interface Set<T>

Overrides:

isEmpty in class AbstractRichIterable<T>

notEmpty

public boolean notEmpty()

Description copied from interface: RichIterable

The English equivalent of !this.isEmpty()

Specified by:

notEmpty in interface RichIterable<T>

select

public <R extends Collection<T>> R select(Predicate<? super T> predicate,
 R target)

Description copied from interface: RichIterable

Same as the select method with one parameter but uses the specified target collection for the results.

Example using a Java 8 lambda expression:

MutableList<Person> selected =
    people.select(person -> person.person.getLastName().equals("Smith"), Lists.mutable.empty());

Specified by:

select in interface RichIterable<T>

Overrides:

select in class AbstractRichIterable<T>

Parameters:

predicate - a Predicate to use as the select criteria

target - the Collection to append to for all elements in this RichIterable that meet select criteria predicate

Returns:

target, which contains appended elements as a result of the select criteria

See Also:

• RichIterable.select(Predicate)

selectWith

public <P, R extends Collection<T>> R selectWith(Predicate2<? super T, ? super P> predicate,
 P parameter,
 R target)

Description copied from interface: RichIterable

Similar to RichIterable.select(Predicate, Collection), except with an evaluation parameter for the second generic argument in Predicate2.

E.g. return a Collection of Person elements where the person has an age greater than or equal to 18 years

Example using a Java 8 lambda expression:

MutableList<Person> selected =
    people.selectWith((Person person, Integer age) -> person.getAge()>= age, Integer.valueOf(18), Lists.mutable.empty());

Specified by:

selectWith in interface RichIterable<T>

Overrides:

selectWith in class AbstractRichIterable<T>

Parameters:

predicate - a Predicate2 to use as the select criteria

parameter - a parameter to pass in for evaluation of the second argument P in predicate

target - the Collection to append to for all elements in this RichIterable that meet select criteria predicate

Returns:

targetCollection, which contains appended elements as a result of the select criteria

See Also:

• RichIterable.select(Predicate)
• RichIterable.select(Predicate, Collection)

reject

public <R extends Collection<T>> R reject(Predicate<? super T> predicate,
 R target)

Description copied from interface: RichIterable

Same as the reject method with one parameter but uses the specified target collection for the results.

Example using a Java 8 lambda expression:

MutableList<Person> rejected =
    people.reject(person -> person.person.getLastName().equals("Smith"), Lists.mutable.empty());

Specified by:

reject in interface RichIterable<T>

Overrides:

reject in class AbstractRichIterable<T>

Parameters:

predicate - a Predicate to use as the reject criteria

target - the Collection to append to for all elements in this RichIterable that cause Predicate#accept(Object) method to evaluate to false

Returns:

target, which contains appended elements as a result of the reject criteria

rejectWith

public <P, R extends Collection<T>> R rejectWith(Predicate2<? super T, ? super P> predicate,
 P parameter,
 R target)

Description copied from interface: RichIterable

Similar to RichIterable.reject(Predicate, Collection), except with an evaluation parameter for the second generic argument in Predicate2.

E.g. return a Collection of Person elements where the person has an age greater than or equal to 18 years

Example using a Java 8 lambda expression:

MutableList<Person> rejected =
    people.rejectWith((Person person, Integer age) -> person.getAge() < age, Integer.valueOf(18), Lists.mutable.empty());

Specified by:

rejectWith in interface RichIterable<T>

Overrides:

rejectWith in class AbstractRichIterable<T>

Parameters:

predicate - a Predicate2 to use as the reject criteria

parameter - a parameter to pass in for evaluation of the second argument P in predicate

target - the Collection to append to for all elements in this RichIterable that cause Predicate#accept(Object) method to evaluate to false

Returns:

targetCollection, which contains appended elements as a result of the reject criteria

See Also:

• RichIterable.reject(Predicate)
• RichIterable.reject(Predicate, Collection)

collect

public <V, R extends Collection<V>> R collect(Function<? super T, ? extends V> function,
 R target)

Description copied from interface: RichIterable

Same as RichIterable.collect(Function), except that the results are gathered into the specified target collection.

Example using a Java 8 lambda expression:

MutableList<String> names =
    people.collect(person -> person.getFirstName() + " " + person.getLastName(), Lists.mutable.empty());

Specified by:

collect in interface RichIterable<T>

Overrides:

collect in class AbstractRichIterable<T>

Parameters:

function - a Function to use as the collect transformation function

target - the Collection to append to for all elements in this RichIterable that meet select criteria function

Returns:

target, which contains appended elements as a result of the collect transformation

See Also:

• RichIterable.collect(Function)

collectWith

public <P, V, R extends Collection<V>> R collectWith(Function2<? super T, ? super P, ? extends V> function,
 P parameter,
 R target)

Description copied from interface: RichIterable

Same as collectWith but with a targetCollection parameter to gather the results.

Example using a Java 8 lambda expression:

MutableSet<Integer> integers =
    Lists.mutable.with(1, 2, 3).collectWith((each, parameter) -> each + parameter, Integer.valueOf(1), Sets.mutable.empty());

Specified by:

collectWith in interface RichIterable<T>

Overrides:

collectWith in class AbstractRichIterable<T>

Parameters:

function - a Function2 to use as the collect transformation function

parameter - a parameter to pass in for evaluation of the second argument P in function

target - the Collection to append to for all elements in this RichIterable that meet select criteria function

Returns:

targetCollection, which contains appended elements as a result of the collect transformation

collectIf

public <V, R extends Collection<V>> R collectIf(Predicate<? super T> predicate,
 Function<? super T, ? extends V> function,
 R target)

Description copied from interface: RichIterable

Same as the collectIf method with two parameters but uses the specified target collection for the results.

Specified by:

collectIf in interface RichIterable<T>

Overrides:

collectIf in class AbstractRichIterable<T>

Parameters:

predicate - a Predicate to use as the select criteria

function - a Function to use as the collect transformation function

target - the Collection to append to for all elements in this RichIterable that meet the collect criteria predicate

Returns:

targetCollection, which contains appended elements as a result of the collect criteria and transformation

See Also:

• RichIterable.collectIf(Predicate, Function)

detectIfNone

public T detectIfNone(Predicate<? super T> predicate,
 Function0<? extends T> function)

Description copied from interface: RichIterable

Returns the first element of the iterable for which the predicate evaluates to true. If no element matches the predicate, then returns the value of applying the specified function.

Specified by:

detectIfNone in interface RichIterable<T>

flatCollect

public <V, R extends Collection<V>> R flatCollect(Function<? super T, ? extends Iterable<V>> function,
 R target)

Description copied from interface: RichIterable

Same as flatCollect, only the results are collected into the target collection.

Specified by:

flatCollect in interface RichIterable<T>

Overrides:

flatCollect in class AbstractRichIterable<T>

Parameters:

function - The Function to apply

target - The collection into which results should be added.

Returns:

target, which will contain a flattened collection of results produced by applying the given function

See Also:

• RichIterable.flatCollect(Function)

detect

public T detect(Predicate<? super T> predicate)

Description copied from interface: RichIterable

Returns the first element of the iterable for which the predicate evaluates to true or null in the case where no element returns true. This method is commonly called find.

Example using a Java 8 lambda expression:

Person person =
    people.detect(person -> person.getFirstName().equals("John") && person.getLastName().equals("Smith"));

Specified by:

detect in interface RichIterable<T>

Overrides:

detect in class AbstractRichIterable<T>

detectOptional

public Optional<T> detectOptional(Predicate<? super T> predicate)

Description copied from interface: RichIterable

Returns the first element of the iterable for which the predicate evaluates to true as an Optional. This method is commonly called find.

Example using a Java 8 lambda expression:

Person person =
    people.detectOptional(person -> person.getFirstName().equals("John") && person.getLastName().equals("Smith"));

Specified by:

detectOptional in interface RichIterable<T>

Overrides:

detectOptional in class AbstractRichIterable<T>

count

public int count(Predicate<? super T> predicate)

Description copied from interface: RichIterable

Return the total number of elements that answer true to the specified predicate.

Example using a Java 8 lambda expression:

int count =
    people.count(person -> person.getAddress().getState().getName().equals("New York"));

Specified by:

count in interface RichIterable<T>

Overrides:

count in class AbstractRichIterable<T>

countWith

public <P> int countWith(Predicate2<? super T, ? super P> predicate,
 P parameter)

Description copied from interface: RichIterable

Returns the total number of elements that evaluate to true for the specified predicate.

e.g.
return lastNames.countWith(Predicates2.equal(), "Smith");

Specified by:

countWith in interface RichIterable<T>

Overrides:

countWith in class AbstractRichIterable<T>

anySatisfy

public boolean anySatisfy(Predicate<? super T> predicate)

Description copied from interface: RichIterable

Returns true if the predicate evaluates to true for any element of the iterable. Returns false if the iterable is empty, or if no element returned true when evaluating the predicate.

Specified by:

anySatisfy in interface RichIterable<T>

Overrides:

anySatisfy in class AbstractRichIterable<T>

allSatisfy

public boolean allSatisfy(Predicate<? super T> predicate)

Description copied from interface: RichIterable

Returns true if the predicate evaluates to true for every element of the iterable or if the iterable is empty. Otherwise, returns false.

Specified by:

allSatisfy in interface RichIterable<T>

Overrides:

allSatisfy in class AbstractRichIterable<T>

noneSatisfy

public boolean noneSatisfy(Predicate<? super T> predicate)

Description copied from interface: RichIterable

Returns true if the predicate evaluates to false for every element of the iterable or if the iterable is empty. Otherwise, returns false.

Specified by:

noneSatisfy in interface RichIterable<T>

Overrides:

noneSatisfy in class AbstractRichIterable<T>

anySatisfyWith

public <P> boolean anySatisfyWith(Predicate2<? super T, ? super P> predicate,
 P parameter)

Description copied from interface: RichIterable

Returns true if the predicate evaluates to true for any element of the collection, or return false. Returns false if the collection is empty.

Specified by:

anySatisfyWith in interface RichIterable<T>

Overrides:

anySatisfyWith in class AbstractRichIterable<T>

allSatisfyWith

public <P> boolean allSatisfyWith(Predicate2<? super T, ? super P> predicate,
 P parameter)

Description copied from interface: RichIterable

Returns true if the predicate evaluates to true for every element of the collection, or returns false.

Specified by:

allSatisfyWith in interface RichIterable<T>

Overrides:

allSatisfyWith in class AbstractRichIterable<T>

noneSatisfyWith

public <P> boolean noneSatisfyWith(Predicate2<? super T, ? super P> predicate,
 P parameter)

Description copied from interface: RichIterable

Returns true if the predicate evaluates to false for every element of the collection, or return false. Returns true if the collection is empty.

Specified by:

noneSatisfyWith in interface RichIterable<T>

Overrides:

noneSatisfyWith in class AbstractRichIterable<T>

injectInto

public <IV> IV injectInto(IV injectedValue,
 Function2<? super IV, ? super T, ? extends IV> function)

Description copied from interface: RichIterable

Returns the final result of evaluating function using each element of the iterable and the previous evaluation result as the parameters. The injected value is used for the first parameter of the first evaluation, and the current item in the iterable is used as the second parameter. This method is commonly called fold or sometimes reduce.

Specified by:

injectInto in interface RichIterable<T>

Overrides:

injectInto in class AbstractRichIterable<T>

injectInto

public int injectInto(int injectedValue,
 IntObjectToIntFunction<? super T> intObjectToIntFunction)

Description copied from interface: RichIterable

Returns the final int result of evaluating function using each element of the iterable and the previous evaluation result as the parameters. The injected value is used for the first parameter of the first evaluation, and the current item in the iterable is used as the second parameter.

Specified by:

injectInto in interface RichIterable<T>

Overrides:

injectInto in class AbstractRichIterable<T>

injectInto

public long injectInto(long injectedValue,
 LongObjectToLongFunction<? super T> longObjectToLongFunction)

Description copied from interface: RichIterable

Returns the final long result of evaluating function using each element of the iterable and the previous evaluation result as the parameters. The injected value is used for the first parameter of the first evaluation, and the current item in the iterable is used as the second parameter.

Specified by:

injectInto in interface RichIterable<T>

Overrides:

injectInto in class AbstractRichIterable<T>

injectInto

public double injectInto(double injectedValue,
 DoubleObjectToDoubleFunction<? super T> doubleObjectToDoubleFunction)

Description copied from interface: RichIterable

Returns the final double result of evaluating function using each element of the iterable and the previous evaluation result as the parameters. The injected value is used for the first parameter of the first evaluation, and the current item in the iterable is used as the second parameter.

Specified by:

injectInto in interface RichIterable<T>

Overrides:

injectInto in class AbstractRichIterable<T>

toString

public String toString()

Description copied from class: AbstractRichIterable

Returns a string with the elements of the iterable separated by commas with spaces and enclosed in square brackets.

Assert.assertEquals("[]", Lists.mutable.empty().toString());
Assert.assertEquals("[1]", Lists.mutable.with(1).toString());
Assert.assertEquals("[1, 2, 3]", Lists.mutable.with(1, 2, 3).toString());

Specified by:

toString in interface RichIterable<T>

Overrides:

toString in class AbstractRichIterable<T>

Returns:

a string representation of this collection.

See Also:

• AbstractCollection.toString()

makeString

public String makeString()

Description copied from interface: RichIterable

Returns a string representation of this collection by delegating to RichIterable.makeString(String) and defaulting the separator parameter to the characters ", " (comma and space).

Specified by:

makeString in interface RichIterable<T>

Returns:

a string representation of this collection.

makeString

public String makeString(String separator)

Description copied from interface: RichIterable

Returns a string representation of this collection by delegating to RichIterable.makeString(String, String, String) and defaulting the start and end parameters to "" (the empty String).

Specified by:

makeString in interface RichIterable<T>

Returns:

a string representation of this collection.

makeString

public String makeString(String start,
 String separator,
 String end)

Description copied from interface: RichIterable

Returns a string representation of this collection with the elements separated by the specified separator and enclosed between the start and end strings.

Specified by:

makeString in interface RichIterable<T>

Returns:

a string representation of this collection.

appendString

public void appendString(Appendable appendable)

Description copied from interface: RichIterable

Prints a string representation of this collection onto the given Appendable. Prints the string returned by RichIterable.makeString().

Specified by:

appendString in interface RichIterable<T>

appendString

public void appendString(Appendable appendable,
 String separator)

Description copied from interface: RichIterable

Prints a string representation of this collection onto the given Appendable. Prints the string returned by RichIterable.makeString(String).

Specified by:

appendString in interface RichIterable<T>

Overrides:

appendString in class AbstractRichIterable<T>

appendString

public void appendString(Appendable appendable,
 String start,
 String separator,
 String end)

Description copied from interface: RichIterable

Prints a string representation of this collection onto the given Appendable. Prints the string returned by RichIterable.makeString(String, String, String).

Specified by:

appendString in interface RichIterable<T>

Overrides:

appendString in class AbstractRichIterable<T>

writeReplace

private Object writeReplace()