MoreCollectors
extends Object| java.lang.Object | |
| ↳ | com.atlassian.bitbucket.util.MoreCollectors |
Class Overview
Additional utility methods missing from Collectors. The implementation of these collectors, where possible, attempts to emulate the behavior of the standard Collectors factories.
Summary
| Public Methods | |||||||||||
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Returns a
Collector that accumulates elements into an immutable list. | |||||||||||
Returns a
Collector that accumulates elements into an immutable map whose keys and values
are the result of applying the provided mapping functions to the input elements. | |||||||||||
Returns a
Collector that accumulates elements into an immutable set. | |||||||||||
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Inherited Methods | |||||||||||
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From class
java.lang.Object
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Public Methods
@Nonnull public static Collector<T, ?, List<T>> toImmutableList ()
Returns a Collector that accumulates elements into an immutable list.
The Stream being collected may contain null elements and, when it does, the collected
list will also contain null elements.
Returns
- a
Collectorwhich collects elements into an immutable list
See Also
@Nonnull public static Collector<T, ?, Map<K, U>> toImmutableMap (Function<? super T, ? extends K> keyMapper, Function<? super T, ? extends U> valueMapper)
Returns a Collector that accumulates elements into an immutable map whose keys and values
are the result of applying the provided mapping functions to the input elements.
The Stream being collected may contain null elements, if the mapping functions handle
nulls. However, like Collectors.toMap(Function, Function), this collector uses a
HashMap to collect keys and values. Since its implementation is uses merge(K, V, BiFunction), the
valueMapper may not produce null values, even for null inputs, or a
NullPointerException will be thrown. The keyMapper, on the other hand, may
return null keys, but may not return duplicate keys or an IllegalStateException
will be thrown.
Parameters
| keyMapper | a mapping function to produce keys, which may return null |
|---|---|
| valueMapper | a mapping function to produce values, which may not return null |
Returns
- a
Collectorwhich collects elements into an immutable map
See Also
@Nonnull public static Collector<T, ?, Set<T>> toImmutableSet ()
Returns a Collector that accumulates elements into an immutable set.
The Stream being collected may contain null elements and, when it does, the collected
set will also contain a null element. Unlike Collectors.toSet(), this collector attempts
to retain the traversal order of the stream's elements.
Returns
- a
Collectorwhich collects elements into an immutable set