Class ImmutableEmptyMap<K,V>

java.lang.Object

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

org.eclipse.collections.impl.map.AbstractMapIterable<K,V>

org.eclipse.collections.impl.map.immutable.AbstractImmutableMap<K,V>

org.eclipse.collections.impl.map.immutable.ImmutableEmptyMap<K,V>

All Implemented Interfaces:

Serializable, Iterable<V>, Map<K,V>, InternalIterable<V>, ImmutableMap<K,V>, ImmutableMapIterable<K,V>, MapIterable<K,V>, UnsortedMapIterable<K,V>, RichIterable<V>

final class ImmutableEmptyMap<K,V>
extends AbstractImmutableMap<K,V>
implements Serializable

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

Nested Class Summary

Nested classes/interfaces inherited from interface Map

Map.Entry<K,V>

Field Summary

Fields

Modifier and Type	Field	Description
(package private) static final ImmutableMap<?,?>	INSTANCE
private static final long	serialVersionUID

Constructor Summary

Constructors

Constructor	Description
ImmutableEmptyMap()

Method Summary

Modifier and Type	Method	Description
<K2,V2> ImmutableMap<K2,V2>	collect(Function2<? super K, ? super V, Pair<K2,V2>> function)	For each key and value of the map the function is evaluated.
<R> ImmutableMap<R,V>	collectKeysUnique(Function2<? super K, ? super V, ? extends R> function)	For each key and value of the map the function is evaluated.
<R> ImmutableMap<K,R>	collectValues(Function2<? super K, ? super V, ? extends R> function)	For each key and value of the map the function is evaluated.
boolean	containsKey(Object key)
boolean	containsValue(Object value)
Pair<K,V>	detect(Predicate2<? super K, ? super V> predicate)	Return the first key and value of the map for which the predicate evaluates to true when they are given as arguments.
void	each(Procedure<? super V> procedure)	The procedure is executed for each element in the iterable.
boolean	equals(Object other)	Follows the same general contract as Map.equals(Object).
ImmutableMap<V,K>	flipUniqueValues()	Return the MapIterable that is obtained by flipping the direction of this map and making the associations from value to key.
void	forEachKey(Procedure<? super K> procedure)	Calls the procedure with each key of the map.
void	forEachKeyValue(Procedure2<? super K, ? super V> procedure)	Calls the procedure with each key-value pair of the map.
void	forEachValue(Procedure<? super V> procedure)	Calls the procedure with each value of the map.
<P> void	forEachWith(Procedure2<? super V, ? 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 V> objectIntProcedure)	Iterates over the iterable passing each element and the current relative int index to the specified instance of ObjectIntProcedure.
V	get(Object key)
V	getIfAbsent(K key, Function0<? extends V> function)	Return the value in the Map that corresponds to the specified key, or if there is no value at the key, return the result of evaluating the specified Function0.
V	getIfAbsentValue(K key, V value)	Return the value in the Map that corresponds to the specified key, or if there is no value at the key, return value.
<P> V	getIfAbsentWith(K key, Function<? super P, ? extends V> function, P parameter)	Return the value in the Map that corresponds to the specified key, or if there is no value at the key, return the result of evaluating the specified function and parameter.
V	getOnly()	Returns the element if the iterable has exactly one element.
int	hashCode()	Follows the same general contract as Map.hashCode().
<A> A	ifPresentApply(K key, Function<? super V, ? extends A> function)	If there is a value in the Map that corresponds to the specified key return the result of applying the specified Function on the value, otherwise return null.
boolean	isEmpty()	Returns true if this iterable has zero items.
Set<K>	keySet()
RichIterable<K>	keysView()	Returns an unmodifiable lazy iterable wrapped around the keySet for the map.
RichIterable<Pair<K,V>>	keyValuesView()	Returns an unmodifiable lazy iterable of key/value pairs wrapped around the entrySet for the map.
boolean	notEmpty()	The English equivalent of !this.isEmpty()
ImmutableMap<K,V>	reject(Predicate2<? super K, ? super V> predicate)	For each key and value of the map the predicate is evaluated, if the result of the evaluation is false, that key and value are returned in a new map.
ImmutableMap<K,V>	select(Predicate2<? super K, ? super V> predicate)	For each key and value of the map the predicate is evaluated, if the result of the evaluation is true, that key and value are returned in a new map.
int	size()	Returns the number of items in this iterable.
String	toString()	Returns a string with the elements of the iterable separated by commas with spaces and enclosed in square brackets.
Collection<V>	values()
RichIterable<V>	valuesView()	Returns an unmodifiable lazy iterable wrapped around the values for the map.
private Object	writeReplace()

Methods inherited from class AbstractImmutableMap

aggregateBy, castToMap, clear, collect, collectBoolean, collectByte, collectChar, collectDouble, collectFloat, collectIf, collectInt, collectLong, collectShort, collectWith, countBy, countByEach, countByWith, detectOptional, entrySet, flatCollect, flip, forEach, groupBy, groupByEach, groupByUniqueKey, iterator, newWithAllKeyValueArguments, newWithAllKeyValues, newWithKeyValue, newWithMap, newWithMapIterable, newWithoutAllKeys, newWithoutKey, partition, partitionWith, put, putAll, reject, rejectWith, remove, select, selectInstancesOf, selectWith, sumByDouble, sumByFloat, sumByInt, sumByLong, tap, toImmutable, toMap, zip, zipWithIndex

Methods inherited from class AbstractMapIterable

allSatisfy, allSatisfyWith, anySatisfy, anySatisfyWith, asLazy, chunk, contains, detect, detectIfNone, detectOptional, detectWith, detectWithIfNone, detectWithOptional, getFirst, getLast, getOrDefault, isAbsent, keyAndValueEquals, keyAndValueHashCode, noneSatisfy, noneSatisfyWith, toArray, toArray

Methods inherited from class AbstractRichIterable

appendString, appendString, collect, collectIf, collectWith, containsAll, containsAllArguments, containsAllIterable, count, countWith, flatCollect, forEach, groupBy, groupByEach, groupByUniqueKey, injectInto, injectInto, injectInto, injectInto, injectInto, into, max, max, maxBy, min, min, minBy, reject, rejectWith, select, selectWith, sumOfDouble, sumOfFloat, sumOfInt, sumOfLong, toBag, toBiMap, toList, toMap, toSet, toSortedBag, toSortedBag, toSortedBagBy, toSortedListBy, toSortedMap, toSortedMap, toSortedMapBy, toSortedSet, toSortedSet, toSortedSetBy, zip, zipWithIndex

Methods inherited from class Object

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

Methods inherited from interface ImmutableMap

aggregateBy, aggregateInPlaceBy, flatCollectWith, reduceBy

Methods inherited from interface InternalIterable

forEach

Methods inherited from interface Map

compute, computeIfAbsent, computeIfPresent, getOrDefault, merge, putIfAbsent, remove, replace, replace, replaceAll

Methods inherited from interface MapIterable

getOrDefault, injectIntoKeyValue, parallelStream, spliterator, stream

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, contains, 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, getFirst, getLast, groupBy, groupByAndCollect, groupByEach, groupByUniqueKey, injectInto, injectInto, injectInto, injectInto, injectInto, injectIntoDouble, injectIntoFloat, injectIntoInt, injectIntoLong, into, makeString, makeString, makeString, makeString, max, max, maxBy, maxByOptional, maxOptional, maxOptional, min, min, minBy, minByOptional, minOptional, minOptional, noneSatisfy, noneSatisfyWith, reduce, reduceBy, reduceInPlace, reduceInPlace, reject, rejectWith, select, selectWith, summarizeDouble, summarizeFloat, summarizeInt, summarizeLong, sumOfDouble, sumOfFloat, sumOfInt, sumOfLong, toArray, toArray, toBag, toBiMap, toImmutableBag, toImmutableBiMap, toImmutableList, 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, zip, zipWithIndex

Field Details

INSTANCE

static final ImmutableMap<?,?> INSTANCE

serialVersionUID

private static final long serialVersionUID

See Also:

• Constant Field Values

Constructor Details

ImmutableEmptyMap

ImmutableEmptyMap()

Method Details

size

public int size()

Description copied from interface: RichIterable

Returns the number of items in this iterable.

Specified by:

size in interface Map<K,V>

Specified by:

size in interface RichIterable<K>

keysView

public RichIterable<K> keysView()

Description copied from interface: MapIterable

Returns an unmodifiable lazy iterable wrapped around the keySet for the map.

Specified by:

keysView in interface MapIterable<K,V>

valuesView

public RichIterable<V> valuesView()

Description copied from interface: MapIterable

Returns an unmodifiable lazy iterable wrapped around the values for the map.

Specified by:

valuesView in interface MapIterable<K,V>

keyValuesView

public RichIterable<Pair<K,V>> keyValuesView()

Description copied from interface: MapIterable

Returns an unmodifiable lazy iterable of key/value pairs wrapped around the entrySet for the map.

Specified by:

keyValuesView in interface MapIterable<K,V>

containsKey

public boolean containsKey(Object key)

Specified by:

containsKey in interface Map<K,V>

Specified by:

containsKey in interface MapIterable<K,V>

See Also:

• Map.containsKey(Object)

containsValue

public boolean containsValue(Object value)

Specified by:

containsValue in interface Map<K,V>

Specified by:

containsValue in interface MapIterable<K,V>

See Also:

• Map.containsValue(Object)

get

public V get(Object key)

Specified by:

get in interface Map<K,V>

Specified by:

get in interface MapIterable<K,V>

See Also:

• Map.get(Object)

keySet

public Set<K> keySet()

Specified by:

keySet in interface Map<K,V>

values

public Collection<V> values()

Specified by:

values in interface Map<K,V>

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 MapIterable<K,V>

Specified by:

toString in interface RichIterable<K>

Overrides:

toString in class AbstractRichIterable<V>

Returns:

a string representation of this collection.

See Also:

• AbstractCollection.toString()

equals

public boolean equals(Object other)

Description copied from interface: MapIterable

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

Specified by:

equals in interface Map<K,V>

Specified by:

equals in interface MapIterable<K,V>

Overrides:

equals in class Object

hashCode

public int hashCode()

Description copied from interface: MapIterable

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

Specified by:

hashCode in interface Map<K,V>

Specified by:

hashCode in interface MapIterable<K,V>

Overrides:

hashCode in class Object

forEachKeyValue

public void forEachKeyValue(Procedure2<? super K, ? super V> procedure)

Description copied from interface: MapIterable

Calls the procedure with each key-value pair of the map.

    final Collection<String> collection = new ArrayList<String>();
    MutableMap<Integer, String> map = this.newMapWithKeysValues(1, "One", 2, "Two", 3, "Three");
    map.forEachKeyValue((Integer key, String value) -> collection.add(String.valueOf(key) + value));
    Verify.assertContainsAll(collection, "1One", "2Two", "3Three");

Specified by:

forEachKeyValue in interface MapIterable<K,V>

flipUniqueValues

public ImmutableMap<V,K> flipUniqueValues()

Description copied from interface: MapIterable

Return the MapIterable that is obtained by flipping the direction of this map and making the associations from value to key.

    MapIterable<Integer, String> map = this.newMapWithKeysValues(1, "1", 2, "2", 3, "3");
    MapIterable<String, Integer> result = map.flipUniqueValues();
    Assert.assertTrue(result.equals(UnifiedMap.newWithKeysValues("1", 1, "2", 2, "3", 3)));

Specified by:

flipUniqueValues in interface ImmutableMap<K,V>

Specified by:

flipUniqueValues in interface ImmutableMapIterable<K,V>

Specified by:

flipUniqueValues in interface MapIterable<K,V>

Specified by:

flipUniqueValues in interface UnsortedMapIterable<K,V>

Overrides:

flipUniqueValues in class AbstractImmutableMap<K,V>

forEachKey

public void forEachKey(Procedure<? super K> procedure)

Description copied from interface: MapIterable

Calls the procedure with each key of the map.

    final Collection<Integer> result = new ArrayList<Integer>();
    MutableMap<Integer, String> map = this.newMapWithKeysValues(1, "1", 2, "2", 3, "3");
    map.forEachKey(new CollectionAddProcedure<Integer>(result));
    Verify.assertContainsAll(result, 1, 2, 3);

Specified by:

forEachKey in interface MapIterable<K,V>

Overrides:

forEachKey in class AbstractMapIterable<K,V>

forEachValue

public void forEachValue(Procedure<? super V> procedure)

Description copied from interface: MapIterable

Calls the procedure with each value of the map.

    Set<String> result = UnifiedSet.newSet();
    MutableMap<Integer, String> map = this.newMapWithKeysValues(1, "One", 2, "Two", 3, "Three", 4, "Four");
    map.forEachValue(new CollectionAddProcedure<String>(result));
    Verify.assertSetsEqual(UnifiedSet.newSetWith("One", "Two", "Three", "Four"), result);

Specified by:

forEachValue in interface MapIterable<K,V>

Overrides:

forEachValue in class AbstractMapIterable<K,V>

forEachWithIndex

public void forEachWithIndex(ObjectIntProcedure<? super V> 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<K>

Overrides:

forEachWithIndex in class AbstractMapIterable<K,V>

forEachWith

public <P> void forEachWith(Procedure2<? super V, ? 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<K>

Overrides:

forEachWith in class AbstractMapIterable<K,V>

isEmpty

public boolean isEmpty()

Description copied from interface: RichIterable

Returns true if this iterable has zero items.

Specified by:

isEmpty in interface Map<K,V>

Specified by:

isEmpty in interface RichIterable<K>

Overrides:

isEmpty in class AbstractRichIterable<V>

notEmpty

public boolean notEmpty()

Description copied from interface: RichIterable

The English equivalent of !this.isEmpty()

Specified by:

notEmpty in interface RichIterable<K>

each

public void each(Procedure<? super V> 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<K>

Overrides:

each in class AbstractMapIterable<K,V>

See Also:

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

ifPresentApply

public <A> A ifPresentApply(K key,
 Function<? super V, ? extends A> function)

Description copied from interface: MapIterable

If there is a value in the Map that corresponds to the specified key return the result of applying the specified Function on the value, otherwise return null.

Specified by:

ifPresentApply in interface MapIterable<K,V>

Overrides:

ifPresentApply in class AbstractMapIterable<K,V>

getIfAbsent

public V getIfAbsent(K key,
 Function0<? extends V> function)

Description copied from interface: MapIterable

Return the value in the Map that corresponds to the specified key, or if there is no value at the key, return the result of evaluating the specified Function0.

Specified by:

getIfAbsent in interface MapIterable<K,V>

Overrides:

getIfAbsent in class AbstractMapIterable<K,V>

getIfAbsentValue

public V getIfAbsentValue(K key,
 V value)

Description copied from interface: MapIterable

Return the value in the Map that corresponds to the specified key, or if there is no value at the key, return value.

Specified by:

getIfAbsentValue in interface MapIterable<K,V>

Overrides:

getIfAbsentValue in class AbstractMapIterable<K,V>

getIfAbsentWith

public <P> V getIfAbsentWith(K key,
 Function<? super P, ? extends V> function,
 P parameter)

Description copied from interface: MapIterable

Return the value in the Map that corresponds to the specified key, or if there is no value at the key, return the result of evaluating the specified function and parameter.

Specified by:

getIfAbsentWith in interface MapIterable<K,V>

Overrides:

getIfAbsentWith in class AbstractMapIterable<K,V>

collect

public <K2,V2> ImmutableMap<K2,V2> collect(Function2<? super K, ? super V, Pair<K2,V2>> function)

Description copied from interface: MapIterable

For each key and value of the map the function is evaluated. The results of these evaluations are returned in a new map. The map returned will use the values projected from the function rather than the original values.

MapIterable<String, String> collected =
    peopleByCity.collect((City city, Person person) -> Pair.of(city.getCountry(), person.getAddress().getCity()));

Specified by:

collect in interface ImmutableMap<K,V>

Specified by:

collect in interface ImmutableMapIterable<K,V>

Specified by:

collect in interface MapIterable<K,V>

Specified by:

collect in interface UnsortedMapIterable<K,V>

Overrides:

collect in class AbstractImmutableMap<K,V>

collectValues

public <R> ImmutableMap<K,R> collectValues(Function2<? super K, ? super V, ? extends R> function)

Description copied from interface: MapIterable

For each key and value of the map the function is evaluated. The results of these evaluations are returned in a new map. The map returned will use the values projected from the function rather than the original values.

MapIterable<City, String> collected =
    peopleByCity.collectValues((City city, Person person) -> person.getFirstName() + " " + person.getLastName());

Specified by:

collectValues in interface ImmutableMap<K,V>

Specified by:

collectValues in interface ImmutableMapIterable<K,V>

Specified by:

collectValues in interface MapIterable<K,V>

Specified by:

collectValues in interface UnsortedMapIterable<K,V>

Overrides:

collectValues in class AbstractImmutableMap<K,V>

collectKeysUnique

public <R> ImmutableMap<R,V> collectKeysUnique(Function2<? super K, ? super V, ? extends R> function)

Description copied from interface: MapIterable

For each key and value of the map the function is evaluated. The results of these evaluations are returned in a new map. The map returned will use the keys projected from the function rather than the original keys.

Specified by:

collectKeysUnique in interface ImmutableMap<K,V>

Specified by:

collectKeysUnique in interface ImmutableMapIterable<K,V>

Specified by:

collectKeysUnique in interface MapIterable<K,V>

Overrides:

collectKeysUnique in class AbstractImmutableMap<K,V>

detect

public Pair<K,V> detect(Predicate2<? super K, ? super V> predicate)

Description copied from interface: MapIterable

Return the first key and value of the map for which the predicate evaluates to true when they are given as arguments. The predicate will only be evaluated until such pair is found or until all the keys and values of the map have been used as arguments. That is, there may be keys and values of the map that are never used as arguments to the predicate. The result is null if predicate does not evaluate to true for any key/value combination.

Pair<City, Person> detected =
    peopleByCity.detect((City city, Person person) -> city.getName().equals("Anytown") && person.getLastName().equals("Smith"));

Specified by:

detect in interface MapIterable<K,V>

Overrides:

detect in class AbstractImmutableMap<K,V>

reject

public ImmutableMap<K,V> reject(Predicate2<? super K, ? super V> predicate)

Description copied from interface: MapIterable

For each key and value of the map the predicate is evaluated, if the result of the evaluation is false, that key and value are returned in a new map.

MapIterable<City, Person> rejected =
    peopleByCity.reject((city, person) -> city.getName().equals("Anytown") && person.getLastName().equals("Smith"));

Specified by:

reject in interface ImmutableMap<K,V>

Specified by:

reject in interface ImmutableMapIterable<K,V>

Specified by:

reject in interface MapIterable<K,V>

Specified by:

reject in interface UnsortedMapIterable<K,V>

Overrides:

reject in class AbstractImmutableMap<K,V>

select

public ImmutableMap<K,V> select(Predicate2<? super K, ? super V> predicate)

Description copied from interface: MapIterable

For each key and value of the map the predicate is evaluated, if the result of the evaluation is true, that key and value are returned in a new map.

MapIterable<City, Person> selected =
    peopleByCity.select((city, person) -> city.getName().equals("Anytown") && person.getLastName().equals("Smith"));

Specified by:

select in interface ImmutableMap<K,V>

Specified by:

select in interface ImmutableMapIterable<K,V>

Specified by:

select in interface MapIterable<K,V>

Specified by:

select in interface UnsortedMapIterable<K,V>

Overrides:

select in class AbstractImmutableMap<K,V>

getOnly

public V 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<K>

Overrides:

getOnly in class AbstractMapIterable<K,V>

Returns:

an element of an iterable.

writeReplace

private Object writeReplace()