Streams (Apache Commons Lang 3.20.0 API)
Description: declaration: package: org.apache.commons.lang3, class: Streams

# Class Streams

java.lang.Object
org.apache.commons.lang3.Streams

@Deprecated public class Streams extends Object
Deprecated.
Use `Streams`.
Provides utility functions, and classes for working with the `java.util.stream` package, or more generally, with Java 8 lambdas. More specifically, it attempts to address the fact that lambdas are supposed not to throw Exceptions, at least not checked Exceptions, AKA instances of `Exception`. This enforces the use of constructs like

        Consumer<java.lang.reflect.Method> consumer = m -> {
            try {
                m.invoke(o, args);
            } catch (Throwable t) {
                throw Functions.rethrow(t);
            }
       };
       stream.forEach(consumer);

Using a `Streams.FailableStream`, this can be rewritten as follows:

        Streams.failable(stream).forEach(m -> m.invoke(o, args));

Obviously, the second version is much more concise and the spirit of Lambda expressions is met better than in the first version.

Since:
  3.10
See Also:
  - `Stream`
  - `Functions`

- ## Nested Class Summary

  Nested Classes
  Modifier and Type
  Class
  Description
  `static class`
  `Streams.ArrayCollector<O>`
  Deprecated.
  Use `Streams.ArrayCollector`.
  `static class`
  `Streams.FailableStream<O>`
  Deprecated.
  Use `Streams.FailableStream`.

- ## Constructor Summary

  Constructors
  Constructor
  Description
  `Streams()`
  Deprecated.
  Constructs a new instance.

- ## Method Summary

  Modifier and Type
  Method
  Description
  `static <O> Streams.FailableStream<O>`
  `stream(Collection<O> stream)`
  Deprecated.
  Converts the given `Collection` into a `Streams.FailableStream`.
  `static <O> Streams.FailableStream<O>`
  `stream(Stream<O> stream)`
  Deprecated.
  Converts the given `stream` into a `Streams.FailableStream`.
  `static <O> Collector<O,?,O[]>`
  `toArray(Class<O> elementType)`
  Deprecated.
  Returns a `Collector` that accumulates the input elements into a new array.

  ### Methods inherited from class Object

  `clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait`

- ## Constructor Details

  - ### Streams

    public Streams()
    Deprecated.
    Constructs a new instance.

- ## Method Details

  - ### stream

    public static <O> Streams.FailableStream<O> stream(Collection<O> stream)
    Deprecated.
    Converts the given `Collection` into a `Streams.FailableStream`. This is basically a simplified, reduced version of the `Stream` class, with the same underlying element stream, except that failable objects, like `Functions.FailablePredicate`, `Functions.FailableFunction`, or `Functions.FailableConsumer` may be applied, instead of `Predicate`, `Function`, or `Consumer`. The idea is to rewrite a code snippet like this:

            final List<O> list;
            final Method m;
            final Function<O,String> mapper = (o) -> {
                try {
                    return (String) m.invoke(o);
                } catch (Throwable t) {
                    throw Functions.rethrow(t);
                }
            };
            final List<String> strList = list.stream()
                .map(mapper).collect(Collectors.toList());

    as follows:

            final List<O> list;
            final Method m;
            final List<String> strList = Functions.stream(list.stream())
                .map((o) -> (String) m.invoke(o)).collect(Collectors.toList());

    While the second version may not be quite as efficient (because it depends on the creation of additional, intermediate objects, of type FailableStream), it is much more concise, and readable, and meets the spirit of Lambdas better than the first version.
    Type Parameters:
      `O` - The streams element type.
    Parameters:
      `stream` - The stream, which is being converted.
    Returns:
      The `Streams.FailableStream`, which has been created by converting the stream.

  - ### stream

    public static <O> Streams.FailableStream<O> stream(Stream<O> stream)
    Deprecated.
    Converts the given `stream` into a `Streams.FailableStream`. This is basically a simplified, reduced version of the `Stream` class, with the same underlying element stream, except that failable objects, like `Functions.FailablePredicate`, `Functions.FailableFunction`, or `Functions.FailableConsumer` may be applied, instead of `Predicate`, `Function`, or `Consumer`. The idea is to rewrite a code snippet like this:

            final List<O> list;
            final Method m;
            final Function<O,String> mapper = (o) -> {
                try {
                    return (String) m.invoke(o);
                } catch (Throwable t) {
                    throw Functions.rethrow(t);
                }
            };
            final List<String> strList = list.stream()
                .map(mapper).collect(Collectors.toList());

    as follows:

            final List<O> list;
            final Method m;
            final List<String> strList = Functions.stream(list.stream())
                .map((o) -> (String) m.invoke(o)).collect(Collectors.toList());

    While the second version may not be quite as efficient (because it depends on the creation of additional, intermediate objects, of type FailableStream), it is much more concise, and readable, and meets the spirit of Lambdas better than the first version.
    Type Parameters:
      `O` - The streams element type.
    Parameters:
      `stream` - The stream, which is being converted.
    Returns:
      The `Streams.FailableStream`, which has been created by converting the stream.

  - ### toArray

    public static <O> Collector<O,?,O[]> toArray(Class<O> elementType)
    Deprecated.
    Returns a `Collector` that accumulates the input elements into a new array.
    Type Parameters:
      `O` - the type of the input elements.
    Parameters:
      `elementType` - Type of an element in the array.
    Returns:
      a `Collector` which collects all the input elements into an array, in encounter order.