LangCollectors¶

public final class org.apache.commons.lang3.stream.LangCollectors[source]¶

Implementations of Collector that implement various reduction operations.

This class is called LangCollectors instead of Collectors to avoid clashes with Collectors.

Since:: 3.13.0

Methods¶

`collect(Collector, Object[])`	Delegates to `Stream#collect(Collector)` for a Stream on the given array.
`joining()`	Returns a `Collector` that concatenates the input elements, separated by the specified delimiter, in encounter order.
`joining(CharSequence)`	Returns a `Collector` that concatenates the input elements, separated by the specified delimiter, in encounter order.
`joining(CharSequence, CharSequence, CharSequence)`	Returns a `Collector` that concatenates the input elements, separated by the specified delimiter, with the specified prefix and suffix, in encounter order.
`joining(CharSequence, CharSequence, CharSequence, Function)`	Returns a `Collector` that concatenates the input elements, separated by the specified delimiter, with the specified prefix and suffix, in encounter order.

@SafeVarargs public static <T, R, A> R collect(Collector<? super T, A, R> collector, T... array)[source]¶

Delegates to Stream#collect(Collector) for a Stream on the given array.

Type parameters:

<T> – The type of the array elements.
<R> – the type of the result.
<A> – the intermediate accumulation type of the Collector.

Parameters:

collector – The Collector describing the reduction.
array – The array, assumed to be unmodified during use, a null array treated as an empty array.

Returns:

The result of the reduction

See also:

Since:

3.16.0

public static Collector<Object, ?, String> joining()[source]¶

Returns a Collector that concatenates the input elements, separated by the specified delimiter, in encounter order.

This is a variation of Collectors#joining() that works with any element class, not just CharSequence.

For example:

Stream.of(Long.valueOf(1), Long.valueOf(2), Long.valueOf(3))
   .collect(LangCollectors.joining())
returns "123"

Returns:: A Collector which concatenates Object elements, separated by the specified delimiter, in encounter order.

public static Collector<Object, ?, String> joining(CharSequence delimiter)[source]¶

Returns a Collector that concatenates the input elements, separated by the specified delimiter, in encounter order.

This is a variation of Collectors#joining(CharSequence) that works with any element class, not just CharSequence.

For example:

Stream.of(Long.valueOf(1), Long.valueOf(2), Long.valueOf(3))
  .collect(LangCollectors.joining("-"))
returns "1-2-3"

Parameters:: delimiter – The delimiter to be used between each element.
Returns:: A Collector which concatenates Object elements, separated by the specified delimiter, in encounter order.

public static Collector<Object, ?, String> joining(CharSequence delimiter, CharSequence prefix, CharSequence suffix)[source]¶

Returns a Collector that concatenates the input elements, separated by the specified delimiter, with the specified prefix and suffix, in encounter order.

This is a variation of Collectors#joining(CharSequence, CharSequence, CharSequence) that works with any element class, not just CharSequence.

For example:

Stream.of(Long.valueOf(1), Long.valueOf(2), Long.valueOf(3))
  .collect(LangCollectors.joining("-", "[", "]"))
returns "[1-2-3]"

Parameters:

delimiter – The delimiter to be used between each element
prefix – The sequence of characters to be used at the beginning of the joined result
suffix – The sequence of characters to be used at the end of the joined result

Returns:

A Collector which concatenates CharSequence elements, separated by the specified delimiter, in encounter order

public static Collector<Object, ?, String> joining(CharSequence delimiter, CharSequence prefix, CharSequence suffix, Function<Object, String> toString)[source]¶

Returns a Collector that concatenates the input elements, separated by the specified delimiter, with the specified prefix and suffix, in encounter order.

This is a variation of Collectors#joining(CharSequence, CharSequence, CharSequence) that works with any element class, not just CharSequence.

For example:

Stream.of(Long.valueOf(1), null, Long.valueOf(3))
  .collect(LangCollectors.joining("-", "[", "]", o -> Objects.toString(o, "NUL")))
returns "[1-NUL-3]"

Parameters:

delimiter – The delimiter to be used between each element
prefix – The sequence of characters to be used at the beginning of the joined result
suffix – The sequence of characters to be used at the end of the joined result
toString – A function that takes an Object and returns a non-null String.

Returns:

A Collector which concatenates CharSequence elements, separated by the specified delimiter, in encounter order