public abstract class RemoteCollectors extends Object
RemoteCollector
s that can be executed in parallel in a distributed environment.RemoteCollector
, Collectors
Constructor and Description |
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RemoteCollectors() |
Modifier and Type | Method and Description |
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static <T,U> RemoteCollector<T,?,Double> |
averagingDouble(ValueExtractor<? super U,? extends Number> extractor)
Returns a
Collector that produces the arithmetic mean of a double-valued function applied to the input elements. |
static <T,U> RemoteCollector<T,?,Double> |
averagingInt(ValueExtractor<? super U,? extends Number> extractor)
Returns a
Collector that produces the arithmetic mean of an integer-valued function applied to the input elements. |
static <T,U> RemoteCollector<T,?,Double> |
averagingLong(ValueExtractor<? super U,? extends Number> extractor)
Returns a
Collector that produces the arithmetic mean of a long-valued function applied to the input elements. |
static <T,A,R,RR> RemoteCollector<T,A,RR> |
collectingAndThen(RemoteCollector<T,A,R> downstream, Remote.Function<R,RR> finisher)
Adapts a
Collector to perform an additional finishing transformation. |
static <T> RemoteCollector<T,?,Long> |
counting()
Returns a
Collector accepting elements of type T that counts the number of input elements. |
static <T,U,K> RemoteCollector<T,?,Map<K,List<T>>> |
groupingBy(ValueExtractor<? super U,? extends K> classifier)
Returns a
Collector implementing a "group by" operation on input elements of type T , grouping elements according to a classification function, and returning the results in a Map . |
static <T,U,K,D,A,M extends Map<K,D>> |
groupingBy(ValueExtractor<? super U,? extends K> extractor, Remote.Supplier<M> mapFactory, RemoteCollector<? super T,A,D> downstream)
Returns a
Collector implementing a cascaded "group by" operation on input elements of type T , grouping elements according to a classification function, and then performing a reduction operation on the values associated with a given key using the specified downstream Collector . |
static <T,U,K,A,D> |
groupingBy(ValueExtractor<? super U,? extends K> classifier, RemoteCollector<? super T,A,D> downstream)
Returns a
Collector implementing a cascaded "group by" operation on input elements of type T , grouping elements according to a classification function, and then performing a reduction operation on the values associated with a given key using the specified downstream Collector . |
static <T,U,A,R> RemoteCollector<T,A,R> |
mapping(Remote.Function<? super T,? extends U> mapper, RemoteCollector<? super U,A,R> downstream)
Adapts a
Collector accepting elements of type U to one accepting elements of type T by applying a mapping function to each input element before accumulation. |
static <T> RemoteCollector<T,?,Optional<T>> |
maxBy(Remote.Comparator<? super T> comparator)
Returns a
Collector that produces the maximal element according to a given Comparator , described as an Optional<T> . |
static <T> RemoteCollector<T,?,Optional<T>> |
minBy(Remote.Comparator<? super T> comparator)
Returns a
Collector that produces the minimal element according to a given Comparator , described as an Optional<T> . |
static <T> RemoteCollector<T,?,Optional<T>> |
reducing(Remote.BinaryOperator<T> op)
Returns a
Collector which performs a reduction of its input elements under a specified BinaryOperator . |
static <T> RemoteCollector<T,SimpleHolder<T>,T> |
reducing(T identity, Remote.BinaryOperator<T> op)
Returns a
Collector which performs a reduction of its input elements under a specified BinaryOperator using the provided identity. |
static <T,U> RemoteCollector<T,?,U> |
reducing(U identity, Remote.BiFunction<? super U,? super T,? extends U> mapper, Remote.BinaryOperator<U> op)
Returns a
Collector which performs a reduction of its input elements under a specified mapping function and BinaryOperator . |
static <T,U> RemoteCollector<T,?,U> |
reducing(U identity, Remote.Function<? super T,? extends U> mapper, Remote.BinaryOperator<U> op)
Returns a
Collector which performs a reduction of its input elements under a specified mapping function and BinaryOperator . |
static <T,U> RemoteCollector<T,?,com.tangosol.internal.util.DoubleSummaryStatistics> |
summarizingDouble(ValueExtractor<? super U,? extends Number> extractor)
Returns a
Collector which applies an double -producing mapping function to each input element, and returns summary statistics for the resulting values. |
static <T,U> RemoteCollector<T,?,com.tangosol.internal.util.IntSummaryStatistics> |
summarizingInt(ValueExtractor<? super U,? extends Number> extractor)
Returns a
Collector which applies an int -producing mapping function to each input element, and returns summary statistics for the resulting values. |
static <T,U> RemoteCollector<T,?,com.tangosol.internal.util.LongSummaryStatistics> |
summarizingLong(ValueExtractor<? super U,? extends Number> extractor)
Returns a
Collector which applies an long -producing mapping function to each input element, and returns summary statistics for the resulting values. |
static <T,U> RemoteCollector<T,?,Double> |
summingDouble(ValueExtractor<? super U,? extends Number> extractor)
Returns a
Collector that produces the sum of a double-valued function applied to the input elements. |
static <T,U> RemoteCollector<T,?,Integer> |
summingInt(ValueExtractor<? super U,? extends Number> extractor)
Returns a
Collector that produces the sum of a integer-valued function applied to the input elements. |
static <T,U> RemoteCollector<T,?,Long> |
summingLong(ValueExtractor<? super U,? extends Number> extractor)
Returns a
Collector that produces the sum of a long-valued function applied to the input elements. |
static <T,C extends Collection<T>> |
toCollection(Remote.Supplier<C> supplier)
Returns a
Collector that accumulates the input elements into a new Collection , in encounter order. |
static <T> RemoteCollector<T,?,List<T>> |
toList()
Returns a
Collector that accumulates the input elements into a new List . |
static <T,U1,U2,K,V> |
toMap(ValueExtractor<? super U1,? extends K> keyMapper, ValueExtractor<? super U2,? extends V> valueMapper)
Returns a
Collector that accumulates elements into a Map whose keys and values are the result of applying the provided mapping functions to the input elements. |
static <T,U1,U2,K,V> |
toMap(ValueExtractor<? super U1,? extends K> keyMapper, ValueExtractor<? super U2,? extends V> valueMapper, Remote.BinaryOperator<V> mergeFunction)
Returns a
Collector that accumulates elements into a Map whose keys and values are the result of applying the provided mapping functions to the input elements. |
static <T,U1,U2,K,V,M extends Map<K,V>> |
toMap(ValueExtractor<? super U1,? extends K> keyExtractor, ValueExtractor<? super U2,? extends V> valueExtractor, Remote.BinaryOperator<V> mergeFunction, Remote.Supplier<M> mapSupplier)
Returns a
Collector that accumulates elements into a Map whose keys and values are the result of applying the provided mapping functions to the input elements. |
static <T> RemoteCollector<T,?,Set<T>> |
toSet()
Returns a
Collector that accumulates the input elements into a new Set . |
static <T> RemoteCollector<T,?,Collection<T>> |
toSortedBag()
Returns a
Collector that accumulates the input elements into a new SortedBag . |
static <T> RemoteCollector<T,?,Collection<T>> |
toSortedBag(Comparator<? super T> comparator)
Returns a
Collector that accumulates the input elements into a new SortedBag . |
static <T> RemoteCollector<T,?,Collection<T>> |
toSortedBag(Remote.Comparator<? super T> comparator)
Returns a
Collector that accumulates the input elements into a new SortedBag . |
static <T> RemoteCollector<T,?,SortedSet<T>> |
toSortedSet()
Returns a
Collector that accumulates the input elements into a new SortedSet . |
static <T> RemoteCollector<T,?,SortedSet<T>> |
toSortedSet(Comparator<? super T> comparator)
Returns a
Collector that accumulates the input elements into a new SortedSet . |
static <T> RemoteCollector<T,?,SortedSet<T>> |
toSortedSet(Remote.Comparator<? super T> comparator)
Returns a
Collector that accumulates the input elements into a new SortedSet . |
public static <T,C extends Collection<T>> RemoteCollector<T,?,C> toCollection(Remote.Supplier<C> supplier)
Collector
that accumulates the input elements into a new Collection
, in encounter order. The Collection
is created by the provided factory.T
- the type of the input elementsC
- the type of the resulting Collection
supplier
- a Supplier
which returns a new, empty Collection
of the appropriate typeCollector
which collects all the input elements into a Collection
, in encounter orderpublic static <T> RemoteCollector<T,?,List<T>> toList()
Collector
that accumulates the input elements into a new List
. There are no guarantees on the type, mutability, serializability, or thread-safety of the List
returned; if more control over the returned List
is required, use toCollection(Remote.Supplier)
.T
- the type of the input elementsCollector
which collects all the input elements into a List
, in encounter orderpublic static <T> RemoteCollector<T,?,Collection<T>> toSortedBag()
Collector
that accumulates the input elements into a new SortedBag
.T
- the type of the input elementsCollector
which collects all the input elements into a List
, in encounter orderpublic static <T> RemoteCollector<T,?,Collection<T>> toSortedBag(Comparator<? super T> comparator)
Collector
that accumulates the input elements into a new SortedBag
.T
- the type of the input elementsCollector
which collects all the input elements into a List
, in encounter orderpublic static <T> RemoteCollector<T,?,Collection<T>> toSortedBag(Remote.Comparator<? super T> comparator)
Collector
that accumulates the input elements into a new SortedBag
.T
- the type of the input elementsCollector
which collects all the input elements into a List
, in encounter orderpublic static <T> RemoteCollector<T,?,Set<T>> toSet()
Collector
that accumulates the input elements into a new Set
. There are no guarantees on the type, mutability, serializability, or thread-safety of the Set
returned; if more control over the returned Set
is required, use toCollection(Remote.Supplier)
.
This is an unordered
Collector.
T
- the type of the input elementsCollector
which collects all the input elements into a Set
public static <T> RemoteCollector<T,?,SortedSet<T>> toSortedSet()
Collector
that accumulates the input elements into a new SortedSet
. There are no guarantees on the type, mutability, serializability, or thread-safety of the SortedSet
returned; if more control over the returned SortedSet
is required, use toCollection(Remote.Supplier)
.
This is an unordered
Collector.
T
- the type of the input elementsCollector
which collects all the input elements into a Set
public static <T> RemoteCollector<T,?,SortedSet<T>> toSortedSet(Comparator<? super T> comparator)
Collector
that accumulates the input elements into a new SortedSet
. There are no guarantees on the type, mutability, serializability, or thread-safety of the SortedSet
returned; if more control over the returned SortedSet
is required, use toCollection(Remote.Supplier)
.
This is an unordered
Collector.
T
- the type of the input elementsCollector
which collects all the input elements into a Set
public static <T> RemoteCollector<T,?,SortedSet<T>> toSortedSet(Remote.Comparator<? super T> comparator)
Collector
that accumulates the input elements into a new SortedSet
. There are no guarantees on the type, mutability, serializability, or thread-safety of the SortedSet
returned; if more control over the returned SortedSet
is required, use toCollection(Remote.Supplier)
.
This is an unordered
Collector.
T
- the type of the input elementsCollector
which collects all the input elements into a Set
public static <T,U,A,R> RemoteCollector<T,A,R> mapping(Remote.Function<? super T,? extends U> mapper, RemoteCollector<? super U,A,R> downstream)
Collector
accepting elements of type U
to one accepting elements of type T
by applying a mapping function to each input element before accumulation.T
- the type of the input elementsU
- type of elements accepted by downstream collectorA
- intermediate accumulation type of the downstream collectorR
- result type of collectormapper
- a function to be applied to the input elementsdownstream
- a collector which will accept mapped valuespublic static <T,A,R,RR> RemoteCollector<T,A,RR> collectingAndThen(RemoteCollector<T,A,R> downstream, Remote.Function<R,RR> finisher)
Collector
to perform an additional finishing transformation. For example, one could adapt the toList()
collector to always produce an immutable list with:
List<String> people
= people.stream().collect(collectingAndThen(toList(),
Collections::unmodifiableList));
T
- the type of the input elementsA
- intermediate accumulation type of the downstream collectorR
- result type of the downstream collectorRR
- result type of the resulting collectordownstream
- a collectorfinisher
- a function to be applied to the final result of the downstream collectorpublic static <T> RemoteCollector<T,?,Long> counting()
Collector
accepting elements of type T
that counts the number of input elements. If no elements are present, the result is 0.T
- the type of the input elementsCollector
that counts the input elementspublic static <T> RemoteCollector<T,?,Optional<T>> minBy(Remote.Comparator<? super T> comparator)
Collector
that produces the minimal element according to a given Comparator
, described as an Optional<T>
.T
- the type of the input elementscomparator
- a Comparator
for comparing elementsCollector
that produces the minimal valuepublic static <T> RemoteCollector<T,?,Optional<T>> maxBy(Remote.Comparator<? super T> comparator)
Collector
that produces the maximal element according to a given Comparator
, described as an Optional<T>
.T
- the type of the input elementscomparator
- a Comparator
for comparing elementsCollector
that produces the maximal valuepublic static <T,U> RemoteCollector<T,?,Integer> summingInt(ValueExtractor<? super U,? extends Number> extractor)
Collector
that produces the sum of a integer-valued function applied to the input elements. If no elements are present, the result is 0.T
- the type of the stream elementsU
- the type of the objects to extract from, which should be either the same as T
, or the key or value type if the T
is InvocableMap.Entry
extractor
- a function extracting the property to be summedCollector
that produces the sum of a derived propertypublic static <T,U> RemoteCollector<T,?,Long> summingLong(ValueExtractor<? super U,? extends Number> extractor)
Collector
that produces the sum of a long-valued function applied to the input elements. If no elements are present, the result is 0.T
- the type of the stream elementsU
- the type of the objects to extract from, which should be either the same as T
, or the key or value type if the T
is InvocableMap.Entry
extractor
- a function extracting the property to be summedCollector
that produces the sum of a derived propertypublic static <T,U> RemoteCollector<T,?,Double> summingDouble(ValueExtractor<? super U,? extends Number> extractor)
Collector
that produces the sum of a double-valued function applied to the input elements. If no elements are present, the result is 0.
The sum returned can vary depending upon the order in which values are recorded, due to accumulated rounding error in addition of values of differing magnitudes. Values sorted by increasing absolute magnitude tend to yield more accurate results. If any recorded value is a NaN
or the sum is at any point a NaN
then the sum will be NaN
.
T
- the type of the stream elementsU
- the type of the objects to extract from, which should be either the same as T
, or the key or value type if the T
is InvocableMap.Entry
extractor
- a function extracting the property to be summedCollector
that produces the sum of a derived propertypublic static <T,U> RemoteCollector<T,?,Double> averagingInt(ValueExtractor<? super U,? extends Number> extractor)
Collector
that produces the arithmetic mean of an integer-valued function applied to the input elements. If no elements are present, the result is 0.T
- the type of the stream elementsU
- the type of the objects to extract from, which should be either the same as T
, or the key or value type if the T
is InvocableMap.Entry
extractor
- a function extracting the property to be summedCollector
that produces the sum of a derived propertypublic static <T,U> RemoteCollector<T,?,Double> averagingLong(ValueExtractor<? super U,? extends Number> extractor)
Collector
that produces the arithmetic mean of a long-valued function applied to the input elements. If no elements are present, the result is 0.T
- the type of the stream elementsU
- the type of the objects to extract from, which should be either the same as T
, or the key or value type if the T
is InvocableMap.Entry
extractor
- a function extracting the property to be averagedCollector
that produces the average of a derived propertypublic static <T,U> RemoteCollector<T,?,Double> averagingDouble(ValueExtractor<? super U,? extends Number> extractor)
Collector
that produces the arithmetic mean of a double-valued function applied to the input elements. If no elements are present, the result is 0.
The average returned can vary depending upon the order in which values are recorded, due to accumulated rounding error in addition of values of differing magnitudes. Values sorted by increasing absolute magnitude tend to yield more accurate results. If any recorded value is a NaN
or the sum is at any point a NaN
then the average will be NaN
.
T
- the type of the stream elementsU
- the type of the objects to extract from, which should be either the same as T
, or the key or value type if the T
is InvocableMap.Entry
extractor
- a function extracting the property to be summedCollector
that produces the sum of a derived propertypublic static <T> RemoteCollector<T,SimpleHolder<T>,T> reducing(T identity, Remote.BinaryOperator<T> op)
Collector
which performs a reduction of its input elements under a specified BinaryOperator
using the provided identity.T
- element type for the input and output of the reductionidentity
- the identity value for the reduction (also, the value that is returned when there are no input elements)op
- a BinaryOperator<T>
used to reduce the input elementsCollector
which implements the reduction operationreducing(Remote.BinaryOperator)
, reducing(Object, Remote.Function, Remote.BinaryOperator)
public static <T> RemoteCollector<T,?,Optional<T>> reducing(Remote.BinaryOperator<T> op)
Collector
which performs a reduction of its input elements under a specified BinaryOperator
. The result is described as an Optional<T>
.T
- element type for the input and output of the reductionop
- a BinaryOperator<T>
used to reduce the input elementsCollector
which implements the reduction operationreducing(Object, Remote.BinaryOperator)
, reducing(Object, Remote.Function, Remote.BinaryOperator)
public static <T,U> RemoteCollector<T,?,U> reducing(U identity, Remote.Function<? super T,? extends U> mapper, Remote.BinaryOperator<U> op)
Collector
which performs a reduction of its input elements under a specified mapping function and BinaryOperator
. This is a generalization of reducing(Object, Remote.BinaryOperator)
which allows a transformation of the elements before reduction.T
- the type of the input elementsU
- the type of the mapped valuesidentity
- the identity value for the reduction (also, the value that is returned when there are no input elements)mapper
- a mapping function to apply to each input valueop
- a BinaryOperator<U>
used to reduce the mapped valuesCollector
implementing the map-reduce operationreducing(Object, Remote.BinaryOperator)
, reducing(Remote.BinaryOperator)
public static <T,U> RemoteCollector<T,?,U> reducing(U identity, Remote.BiFunction<? super U,? super T,? extends U> mapper, Remote.BinaryOperator<U> op)
Collector
which performs a reduction of its input elements under a specified mapping function and BinaryOperator
. This is a generalization of reducing(Object, Remote.BinaryOperator)
which allows a transformation of the elements before reduction.T
- the type of the input elementsU
- the type of the mapped valuesidentity
- the identity value for the reduction (also, the value that is returned when there are no input elements)mapper
- a mapping function to apply to each input valueop
- a BinaryOperator<U>
used to reduce the mapped valuesCollector
implementing the map-reduce operationreducing(Object, Remote.BinaryOperator)
, reducing(Remote.BinaryOperator)
public static <T,U,K> RemoteCollector<T,?,Map<K,List<T>>> groupingBy(ValueExtractor<? super U,? extends K> classifier)
Collector
implementing a "group by" operation on input elements of type T
, grouping elements according to a classification function, and returning the results in a Map
.
The classification function maps elements to some key type K
. The collector produces a Map<K, List<T>>
whose keys are the values resulting from applying the classification function to the input elements, and whose corresponding values are List
s containing the input elements which map to the associated key under the classification function.
There are no guarantees on the type, mutability, serializability, or thread-safety of the Map
or List
objects returned.
T
- the type of the stream elementsU
- the type of the objects to extract from, which should be either the same as T
, or the key or value type if the T
is InvocableMap.Entry
K
- the type of the keysclassifier
- the classifier function mapping input elements to keysCollector
implementing the group-by operationgroupingBy(ValueExtractor, RemoteCollector)
, groupingBy(ValueExtractor, Remote.Supplier, RemoteCollector)
public static <T,U,K,A,D> RemoteCollector<T,?,Map<K,D>> groupingBy(ValueExtractor<? super U,? extends K> classifier, RemoteCollector<? super T,A,D> downstream)
Collector
implementing a cascaded "group by" operation on input elements of type T
, grouping elements according to a classification function, and then performing a reduction operation on the values associated with a given key using the specified downstream Collector
.
The classification function maps elements to some key type K
. The downstream collector operates on elements of type T
and produces a result of type D
. The resulting collector produces a Map<K, D>
.
There are no guarantees on the type, mutability, serializability, or thread-safety of the Map
returned.
For example, to compute the set of last names of people in each city:
Map<City, Set<String>> namesByCity
= people.stream().collect(groupingBy(Person::getCity,
mapping(Person::getLastName,
toSet())));
T
- the type of the stream elementsU
- the type of the objects to extract from, which should be either the same as T
, or the key or value type if the T
is InvocableMap.Entry
K
- the type of the keysA
- the intermediate accumulation type of the downstream collectorD
- the result type of the downstream reductionclassifier
- a classifier function mapping input elements to keysdownstream
- a Collector
implementing the downstream reductionCollector
implementing the cascaded group-by operationgroupingBy(ValueExtractor)
, groupingBy(ValueExtractor, Remote.Supplier, RemoteCollector)
public static <T,U,K,D,A,M extends Map<K,D>> RemoteCollector<T,?,M> groupingBy(ValueExtractor<? super U,? extends K> extractor, Remote.Supplier<M> mapFactory, RemoteCollector<? super T,A,D> downstream)
Collector
implementing a cascaded "group by" operation on input elements of type T
, grouping elements according to a classification function, and then performing a reduction operation on the values associated with a given key using the specified downstream Collector
. The Map
produced by the Collector is created with the supplied factory function.
The classification function maps elements to some key type K
. The downstream collector operates on elements of type T
and produces a result of type D
. The resulting collector produces a Map<K, D>
.
For example, to compute the set of last names of people in each city, where the city names are sorted:
Map<City, Set<String>> namesByCity
= people.stream().collect(groupingBy(Person::getCity,
TreeMap::new,
mapping(Person::getLastName,
toSet())));
T
- the type of the stream elementsU
- the type of the objects to extract from, which should be either the same as T
, or the key or value type if the T
is InvocableMap.Entry
K
- the type of the keysA
- the intermediate accumulation type of the downstream collectorD
- the result type of the downstream reductionM
- the type of the resulting Map
extractor
- an extractor function mapping input elements to keysdownstream
- a Collector
implementing the downstream reductionmapFactory
- a function which, when called, produces a new empty Map
of the desired typeCollector
implementing the cascaded group-by operationgroupingBy(ValueExtractor, RemoteCollector)
, groupingBy(ValueExtractor)
public static <T,U1,U2,K,V> RemoteCollector<T,?,Map<K,V>> toMap(ValueExtractor<? super U1,? extends K> keyMapper, ValueExtractor<? super U2,? extends V> valueMapper)
Collector
that accumulates elements into a Map
whose keys and values are the result of applying the provided mapping functions to the input elements.
If the mapped keys contains duplicates (according to Object.equals(Object)
), an IllegalStateException
is thrown when the collection operation is performed. If the mapped keys may have duplicates, use toMap(ValueExtractor, ValueExtractor, Remote.BinaryOperator)
instead.
T
- the type of the stream elementsU1
- the type of the objects to extract keys from, which should be either the same as T
, or the key or value type if the T
is InvocableMap.Entry
U1
- the type of the objects to extract values from, which should be either the same as T
, or the key or value type if the T
is InvocableMap.Entry
K
- the output type of the key mapping functionV
- the output type of the value mapping functionkeyMapper
- a mapping function to produce keysvalueMapper
- a mapping function to produce valuesCollector
which collects elements into a Map
whose keys and values are the result of applying mapping functions to the input elementstoMap(ValueExtractor, ValueExtractor, Remote.BinaryOperator)
, toMap(ValueExtractor, ValueExtractor, Remote.BinaryOperator, Remote.Supplier)
public static <T,U1,U2,K,V> RemoteCollector<T,?,Map<K,V>> toMap(ValueExtractor<? super U1,? extends K> keyMapper, ValueExtractor<? super U2,? extends V> valueMapper, Remote.BinaryOperator<V> mergeFunction)
Collector
that accumulates elements into a Map
whose keys and values are the result of applying the provided mapping functions to the input elements.
If the mapped keys contains duplicates (according to Object.equals(Object)
), the value mapping function is applied to each equal element, and the results are merged using the provided merging function.
T
- the type of the stream elementsU1
- the type of the objects to extract keys from, which should be either the same as T
, or the key or value type if the T
is InvocableMap.Entry
U1
- the type of the objects to extract values from, which should be either the same as T
, or the key or value type if the T
is InvocableMap.Entry
K
- the output type of the key mapping functionV
- the output type of the value mapping functionkeyMapper
- a mapping function to produce keysvalueMapper
- a mapping function to produce valuesmergeFunction
- a merge function, used to resolve collisions between values associated with the same key, as supplied to Map.merge(Object, Object, BiFunction)
Collector
which collects elements into a Map
whose keys are the result of applying a key mapping function to the input elements, and whose values are the result of applying a value mapping function to all input elements equal to the key and combining them using the merge functiontoMap(ValueExtractor, ValueExtractor)
, toMap(ValueExtractor, ValueExtractor, Remote.BinaryOperator, Remote.Supplier)
public static <T,U1,U2,K,V,M extends Map<K,V>> RemoteCollector<T,?,M> toMap(ValueExtractor<? super U1,? extends K> keyExtractor, ValueExtractor<? super U2,? extends V> valueExtractor, Remote.BinaryOperator<V> mergeFunction, Remote.Supplier<M> mapSupplier)
Collector
that accumulates elements into a Map
whose keys and values are the result of applying the provided mapping functions to the input elements.
If the mapped keys contains duplicates (according to Object.equals(Object)
), the value mapping function is applied to each equal element, and the results are merged using the provided merging function. The Map
is created by a provided supplier function.
T
- the type of the stream elementsU1
- the type of the objects to extract keys from, which should be either the same as T
, or the key or value type if the T
is InvocableMap.Entry
U1
- the type of the objects to extract values from, which should be either the same as T
, or the key or value type if the T
is InvocableMap.Entry
K
- the output type of the key mapping functionV
- the output type of the value mapping functionM
- the type of the resulting Map
keyExtractor
- a mapping function to produce keysvalueExtractor
- a mapping function to produce valuesmergeFunction
- a merge function, used to resolve collisions between values associated with the same key, as supplied to Map.merge(Object, Object, BiFunction)
mapSupplier
- a function which returns a new, empty Map
into which the results will be insertedCollector
which collects elements into a Map
whose keys are the result of applying a key mapping function to the input elements, and whose values are the result of applying a value mapping function to all input elements equal to the key and combining them using the merge functiontoMap(ValueExtractor, ValueExtractor)
, toMap(ValueExtractor, ValueExtractor, Remote.BinaryOperator)
public static <T,U> RemoteCollector<T,?,com.tangosol.internal.util.IntSummaryStatistics> summarizingInt(ValueExtractor<? super U,? extends Number> extractor)
Collector
which applies an int
-producing mapping function to each input element, and returns summary statistics for the resulting values.T
- the type of the stream elementsU
- the type of the objects to extract from, which should be either the same as T
, or the key or value type if the T
is InvocableMap.Entry
extractor
- a mapping function to apply to each elementCollector
implementing the summary-statistics reductionsummarizingDouble(ValueExtractor)
, summarizingLong(ValueExtractor)
public static <T,U> RemoteCollector<T,?,com.tangosol.internal.util.LongSummaryStatistics> summarizingLong(ValueExtractor<? super U,? extends Number> extractor)
Collector
which applies an long
-producing mapping function to each input element, and returns summary statistics for the resulting values.T
- the type of the stream elementsU
- the type of the objects to extract from, which should be either the same as T
, or the key or value type if the T
is InvocableMap.Entry
extractor
- a mapping function to apply to each elementCollector
implementing the summary-statistics reductionsummarizingDouble(ValueExtractor)
, summarizingInt(ValueExtractor)
public static <T,U> RemoteCollector<T,?,com.tangosol.internal.util.DoubleSummaryStatistics> summarizingDouble(ValueExtractor<? super U,? extends Number> extractor)
Collector
which applies an double
-producing mapping function to each input element, and returns summary statistics for the resulting values.T
- the type of the stream elementsU
- the type of the objects to extract from, which should be either the same as T
, or the key or value type if the T
is InvocableMap.Entry
extractor
- a mapping function to apply to each elementCollector
implementing the summary-statistics reductionsummarizingLong(ValueExtractor)
, summarizingInt(ValueExtractor)