Class EmptyList<T>

java.lang.Object

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

org.eclipse.collections.impl.collection.mutable.AbstractMutableCollection<T>

org.eclipse.collections.impl.list.mutable.AbstractMutableList<T>

org.eclipse.collections.impl.list.fixed.AbstractMemoryEfficientMutableList<T>

org.eclipse.collections.impl.list.fixed.EmptyList<T>

All Implemented Interfaces:

Serializable, Cloneable, Iterable<T>, Collection<T>, List<T>, RandomAccess, SequencedCollection<T>, FixedSizeCollection<T>, MutableCollection<T>, InternalIterable<T>, FixedSizeList<T>, ListIterable<T>, MutableList<T>, OrderedIterable<T>, ReversibleIterable<T>, RichIterable<T>

final class EmptyList<T>
extends AbstractMemoryEfficientMutableList<T>
implements Serializable

This class is a memory efficient list with no elements. It is created by calling Lists.fixedSize.of() which actually returns a singleton instance.

Field Summary

Fields

Modifier and Type	Field	Description
private static final long	serialVersionUID

Constructor Summary

Constructors

Constructor	Description
EmptyList()

Method Summary

Modifier and Type	Method	Description
EmptyList<T>	clone()
boolean	contains(Object obj)	Returns true if the iterable has an element which responds true to element.equals(object).
void	each(Procedure<? super T> procedure)	The procedure is executed for each element in the iterable.
<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	get(int index)	Returns the item at the specified position in this list iterable.
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.
Iterator<T>	iterator()
ListIterator<T>	listIterator()
ListIterator<T>	listIterator(int index)
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.
private Object	readResolve()
void	replaceAll(UnaryOperator<T> operator)
T	set(int index, T element)
int	size()	Returns the number of items in this iterable.
void	sort(Comparator<? super T> comparator)	This method checks if comparator is null and use a ComparableComparator if it is.
EmptyList<T>	sortThis(Comparator<? super T> comparator)	Sorts the internal data structure of this list and returns the list itself as a convenience.
<V extends Comparable<? super V>> MutableList<T>	sortThisBy(Function<? super T, ? extends V> function)	Sorts the internal data structure of this list based on the natural order of the attribute returned by function.
MutableList<T>	sortThisByBoolean(BooleanFunction<? super T> function)
MutableList<T>	sortThisByByte(ByteFunction<? super T> function)
MutableList<T>	sortThisByChar(CharFunction<? super T> function)
MutableList<T>	sortThisByDouble(DoubleFunction<? super T> function)
MutableList<T>	sortThisByFloat(FloatFunction<? super T> function)
MutableList<T>	sortThisByInt(IntFunction<? super T> function)
MutableList<T>	sortThisByLong(LongFunction<? super T> function)
MutableList<T>	sortThisByShort(ShortFunction<? super T> function)
ImmutableList<T>	toImmutable()	Converts this MutableCollection to an ImmutableCollection.
SingletonList<T>	with(T value)	This method allows mutable and fixed size collections the ability to add elements to their existing elements.
<S> MutableList<Pair<T,S>>	zip(Iterable<S> that)	Returns a RichIterable formed from this RichIterable and another RichIterable by combining corresponding elements in pairs.
MutableList<Pair<T,Integer>>	zipWithIndex()	Zips this RichIterable with its indices.

Methods inherited from class AbstractMemoryEfficientMutableList

add, add, addAll, addAll, addAllIterable, clear, remove, remove, removeAll, removeAllIterable, removeIf, removeIfWith, retainAll, retainAllIterable, subList, tap, toReversed, withAll, without, withoutAll

Methods inherited from class AbstractMutableList

allSatisfy, allSatisfyWith, anySatisfy, anySatisfyWith, appendString, appendString, asParallel, asReversed, asSynchronized, asUnmodifiable, binarySearch, chunk, collect, collectIf, collectWith, containsAll, corresponds, count, countWith, detect, detectIndex, detectLastIndex, detectOptional, detectWith, detectWithOptional, distinct, distinct, distinctBy, drop, dropWhile, equals, flatCollect, forEach, forEachWithIndex, groupBy, groupByEach, groupByUniqueKey, hashCode, indexOf, injectInto, injectInto, injectInto, injectInto, injectIntoWith, lastIndexOf, newEmpty, noneSatisfy, noneSatisfyWith, partition, partitionWhile, partitionWith, reject, rejectWith, removeRange, select, selectAndRejectWith, selectInstancesOf, selectWith, sumOfDouble, sumOfFloat, sumOfInt, sumOfLong, take, takeWhile, toSet, toSortedList, zip, zipWithIndex

Methods inherited from class AbstractMutableCollection

countBy, countByEach, countByWith, reduce, sumByDouble, sumByFloat, sumByInt, sumByLong

Methods inherited from class AbstractRichIterable

asLazy, containsAllArguments, containsAllIterable, detectWithIfNone, forEach, groupBy, groupByEach, groupByUniqueKey, injectInto, into, isEmpty, toBag, toBiMap, toList, toMap, toSortedBag, toSortedBag, toSortedBagBy, toSortedListBy, toSortedMap, toSortedMap, toSortedMapBy, toSortedSet, toSortedSet, toSortedSetBy, toString

Methods inherited from class Object

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

Methods inherited from interface Collection

parallelStream, removeIf, stream, toArray

Methods inherited from interface FixedSizeList

sortThis

Methods inherited from interface InternalIterable

forEach

Methods inherited from interface List

addFirst, addLast, containsAll, equals, hashCode, isEmpty, lastIndexOf, removeFirst, removeLast, reversed, spliterator

Methods inherited from interface ListIterable

asParallel, binarySearch, binarySearch, equals, forEachInBoth, hashCode, lastIndexOf

Methods inherited from interface MutableCollection

aggregateBy, aggregateInPlaceBy, countBy, countByEach, countByWith, groupByUniqueKey, injectIntoWith, selectAndRejectWith, sumByDouble, sumByFloat, sumByInt, sumByLong

Methods inherited from interface MutableList

asSynchronized, asUnmodifiable, collect, collectBoolean, collectByte, collectChar, collectDouble, collectFloat, collectIf, collectInt, collectLong, collectShort, collectWith, collectWithIndex, distinct, distinct, distinctBy, drop, dropWhile, flatCollect, flatCollectWith, groupBy, groupByEach, indexOf, newEmpty, partition, partitionWhile, partitionWith, reject, rejectWith, rejectWithIndex, reverseThis, select, selectInstancesOf, selectWith, selectWithIndex, shuffleThis, shuffleThis, take, takeWhile, toArray, toArray, toImmutableList

Methods inherited from interface OrderedIterable

collectWithIndex, corresponds, detectIndex, forEach, forEachWithIndex, getFirstOptional, getLastOptional, rejectWithIndex, selectWithIndex, toStack, zip, zipWithIndex

Methods inherited from interface ReversibleIterable

asReversed, detectLastIndex, reverseForEach, reverseForEachWithIndex

Methods inherited from interface RichIterable

aggregateBy, allSatisfy, allSatisfyWith, anySatisfy, anySatisfyWith, appendString, appendString, appendString, asLazy, chunk, collect, collectBoolean, collectByte, collectChar, collectDouble, collectFloat, collectIf, collectInt, collectLong, collectShort, collectWith, containsAll, containsAllArguments, containsAllIterable, containsAny, containsAnyIterable, containsBy, containsNone, containsNoneIterable, count, countBy, countByEach, countByWith, countWith, detect, detectIfNone, detectOptional, detectWith, detectWithIfNone, detectWithOptional, flatCollect, flatCollectBoolean, flatCollectByte, flatCollectChar, flatCollectDouble, flatCollectFloat, flatCollectInt, flatCollectLong, flatCollectShort, flatCollectWith, forEach, getAny, groupBy, groupByAndCollect, groupByEach, groupByUniqueKey, injectInto, injectInto, injectInto, injectInto, injectInto, injectIntoDouble, injectIntoFloat, injectIntoInt, injectIntoLong, into, isEmpty, makeString, makeString, makeString, makeString, maxByOptional, maxOptional, maxOptional, minByOptional, minOptional, minOptional, noneSatisfy, noneSatisfyWith, notEmpty, reduce, reduceBy, reduceBy, reduceInPlace, reduceInPlace, reject, rejectWith, select, selectWith, summarizeDouble, summarizeFloat, summarizeInt, summarizeLong, sumOfDouble, sumOfFloat, sumOfInt, sumOfLong, toArray, toArray, toBag, toBiMap, toImmutableBag, toImmutableBiMap, toImmutableMap, toImmutableSet, 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, toString

Field Details

serialVersionUID

private static final long serialVersionUID

See Also:

• Constant Field Values

Constructor Details

EmptyList

EmptyList()

Method Details

readResolve

private Object readResolve()

with

public SingletonList<T> with(T value)

Description copied from interface: MutableCollection

This method allows mutable and fixed size collections the ability to add elements to their existing elements. In order to support fixed size a new instance of a collection would have to be returned taking the elements of the original collection and appending the new element to form the new collection. In the case of mutable collections, the original collection is modified, and is returned. In order to use this method properly with mutable and fixed size collections the following approach must be taken:

MutableCollection<String> list = list.with("1");
list = list.with("2");
return list;

In the case of FixedSizeCollection a new instance of MutableCollection will be returned by with, and any variables that previously referenced the original collection will need to be redirected to reference the new instance. For other MutableCollection types you will replace the reference to collection with the same collection, since the instance will return "this" after calling add on itself.

Specified by:

with in interface FixedSizeCollection<T>

Specified by:

with in interface FixedSizeList<T>

Specified by:

with in interface MutableCollection<T>

Specified by:

with in interface MutableList<T>

See Also:

• Collection.add(Object)

clone

public EmptyList<T> clone()

Specified by:

clone in interface MutableList<T>

Overrides:

clone in class AbstractMemoryEfficientMutableList<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 List<T>

Specified by:

size in interface RichIterable<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 List<T>

Specified by:

contains in interface RichIterable<T>

Overrides:

contains in class AbstractMutableList<T>

get

public T get(int index)

Description copied from interface: ListIterable

Returns the item at the specified position in this list iterable.

Specified by:

get in interface List<T>

Specified by:

get in interface ListIterable<T>

set

public T set(int index,
 T element)

Specified by:

set in interface List<T>

replaceAll

public void replaceAll(UnaryOperator<T> operator)

Specified by:

replaceAll in interface List<T>

Since:

10.0 - Overridden for efficiency

sort

public void sort(Comparator<? super T> comparator)

Description copied from class: AbstractMemoryEfficientMutableList

This method checks if comparator is null and use a ComparableComparator if it is.

Specified by:

sort in interface List<T>

Overrides:

sort in class AbstractMemoryEfficientMutableList<T>

Since:

10.0 - Overridden for efficiency

sortThis

public EmptyList<T> sortThis(Comparator<? super T> comparator)

Description copied from interface: MutableList

Sorts the internal data structure of this list and returns the list itself as a convenience.

Specified by:

sortThis in interface FixedSizeList<T>

Specified by:

sortThis in interface MutableList<T>

sortThisBy

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

Description copied from interface: MutableList

Sorts the internal data structure of this list based on the natural order of the attribute returned by function.

Specified by:

sortThisBy in interface MutableList<T>

sortThisByInt

public MutableList<T> sortThisByInt(IntFunction<? super T> function)

Specified by:

sortThisByInt in interface MutableList<T>

Overrides:

sortThisByInt in class AbstractMutableList<T>

sortThisByBoolean

public MutableList<T> sortThisByBoolean(BooleanFunction<? super T> function)

Specified by:

sortThisByBoolean in interface MutableList<T>

Overrides:

sortThisByBoolean in class AbstractMutableList<T>

sortThisByChar

public MutableList<T> sortThisByChar(CharFunction<? super T> function)

Specified by:

sortThisByChar in interface MutableList<T>

Overrides:

sortThisByChar in class AbstractMutableList<T>

sortThisByByte

public MutableList<T> sortThisByByte(ByteFunction<? super T> function)

Specified by:

sortThisByByte in interface MutableList<T>

Overrides:

sortThisByByte in class AbstractMutableList<T>

sortThisByShort

public MutableList<T> sortThisByShort(ShortFunction<? super T> function)

Specified by:

sortThisByShort in interface MutableList<T>

Overrides:

sortThisByShort in class AbstractMutableList<T>

sortThisByFloat

public MutableList<T> sortThisByFloat(FloatFunction<? super T> function)

Specified by:

sortThisByFloat in interface MutableList<T>

Overrides:

sortThisByFloat in class AbstractMutableList<T>

sortThisByLong

public MutableList<T> sortThisByLong(LongFunction<? super T> function)

Specified by:

sortThisByLong in interface MutableList<T>

Overrides:

sortThisByLong in class AbstractMutableList<T>

sortThisByDouble

public MutableList<T> sortThisByDouble(DoubleFunction<? super T> function)

Specified by:

sortThisByDouble in interface MutableList<T>

Overrides:

sortThisByDouble in class AbstractMutableList<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 List<T>

Specified by:

getFirst in interface ListIterable<T>

Specified by:

getFirst in interface MutableList<T>

Specified by:

getFirst in interface OrderedIterable<T>

Specified by:

getFirst in interface RichIterable<T>

Specified by:

getFirst in interface SequencedCollection<T>

Overrides:

getFirst in class AbstractMutableList<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 List<T>

Specified by:

getLast in interface ListIterable<T>

Specified by:

getLast in interface MutableList<T>

Specified by:

getLast in interface OrderedIterable<T>

Specified by:

getLast in interface RichIterable<T>

Specified by:

getLast in interface SequencedCollection<T>

Overrides:

getLast in class AbstractMutableList<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.

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>

Overrides:

each in class AbstractMutableList<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>

Specified by:

forEachWithIndex in interface OrderedIterable<T>

Overrides:

forEachWithIndex in class AbstractMutableList<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 AbstractMutableList<T>

iterator

public Iterator<T> iterator()

Specified by:

iterator in interface Collection<T>

Specified by:

iterator in interface Iterable<T>

Specified by:

iterator in interface List<T>

Overrides:

iterator in class AbstractMutableList<T>

listIterator

public ListIterator<T> listIterator()

Specified by:

listIterator in interface List<T>

Specified by:

listIterator in interface ListIterable<T>

Overrides:

listIterator in class AbstractMemoryEfficientMutableList<T>

See Also:

• List.listIterator()

listIterator

public ListIterator<T> listIterator(int index)

Specified by:

listIterator in interface List<T>

Specified by:

listIterator in interface ListIterable<T>

Overrides:

listIterator in class AbstractMemoryEfficientMutableList<T>

See Also:

• List.listIterator(int)

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 AbstractMutableList<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 AbstractMutableList<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 OrderedIterable<T>

Specified by:

min in interface RichIterable<T>

Overrides:

min in class AbstractMutableList<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 OrderedIterable<T>

Specified by:

max in interface RichIterable<T>

Overrides:

max in class AbstractMutableList<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 AbstractMutableList<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 AbstractMutableList<T>

zip

public <S> MutableList<Pair<T,S>> zip(Iterable<S> that)

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 ListIterable<T>

Specified by:

zip in interface MutableCollection<T>

Specified by:

zip in interface MutableList<T>

Specified by:

zip in interface OrderedIterable<T>

Specified by:

zip in interface ReversibleIterable<T>

Specified by:

zip in interface RichIterable<T>

Overrides:

zip in class AbstractMutableList<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.

zipWithIndex

public MutableList<Pair<T,Integer>> zipWithIndex()

Description copied from interface: RichIterable

Zips this RichIterable with its indices.

Specified by:

zipWithIndex in interface ListIterable<T>

Specified by:

zipWithIndex in interface MutableCollection<T>

Specified by:

zipWithIndex in interface MutableList<T>

Specified by:

zipWithIndex in interface OrderedIterable<T>

Specified by:

zipWithIndex in interface ReversibleIterable<T>

Specified by:

zipWithIndex in interface RichIterable<T>

Overrides:

zipWithIndex in class AbstractMutableList<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)

toImmutable

public ImmutableList<T> toImmutable()

Description copied from interface: MutableCollection

Converts this MutableCollection to an ImmutableCollection.

Specified by:

toImmutable in interface ListIterable<T>

Specified by:

toImmutable in interface MutableCollection<T>

Specified by:

toImmutable in interface MutableList<T>