Lightweight-Stream-API Test

Hamcrest and Mockito matchers for Lightweight-Stream-API

License

License

GroupId

GroupId

com.annimon
ArtifactId

ArtifactId

stream-test
Last Version

Last Version

1.2.2
Release Date

Release Date

Type

Type

jar
Description

Description

Lightweight-Stream-API Test
Hamcrest and Mockito matchers for Lightweight-Stream-API
Project URL

Project URL

https://github.com/aNNiMON/Lightweight-Stream-API
Source Code Management

Source Code Management

https://github.com/aNNiMON/Lightweight-Stream-API

Download stream-test

How to add to project

<!-- https://jarcasting.com/artifacts/com.annimon/stream-test/ -->
<dependency>
    <groupId>com.annimon</groupId>
    <artifactId>stream-test</artifactId>
    <version>1.2.2</version>
</dependency>
// https://jarcasting.com/artifacts/com.annimon/stream-test/
implementation 'com.annimon:stream-test:1.2.2'
// https://jarcasting.com/artifacts/com.annimon/stream-test/
implementation ("com.annimon:stream-test:1.2.2")
'com.annimon:stream-test:jar:1.2.2'
<dependency org="com.annimon" name="stream-test" rev="1.2.2">
  <artifact name="stream-test" type="jar" />
</dependency>
@Grapes(
@Grab(group='com.annimon', module='stream-test', version='1.2.2')
)
libraryDependencies += "com.annimon" % "stream-test" % "1.2.2"
[com.annimon/stream-test "1.2.2"]

Dependencies

compile (3)

Group / Artifact Type Version
com.annimon : stream jar 1.2.2
org.hamcrest : hamcrest-core jar 2.2
org.mockito : mockito-core jar 3.8.0

Project Modules

There are no modules declared in this project.

Lightweight-Stream-API

Coverage Status SonarCloud Status SonarCloud Quality Gate
Build Status Maven Central JavaDocs

Stream API from Java 8 rewritten on iterators for Java 7 and below.

Includes

  • Functional interfaces (Supplier, Function, Consumer etc);
  • Stream/IntStream/LongStream/DoubleStream (without parallel processing, but with a variety of additional methods and with custom operators);
  • Optional/OptionalBoolean/OptionalInt/OptionalLong/OptionalDouble classes;
  • Exceptional class - functional way to deal with exceptions;
  • Objects from Java 7.

Usage

Stream.of(/* array | list | set | map | anything based on Iterator/Iterable interface */)
    .filter(..)
    .map(..)
    ...
    .sorted()
    .forEach(..);
Stream.of(value1, value2, value3)...
IntStream.range(0, 10)...

Example project: https://github.com/aNNiMON/Android-Java-8-Stream-Example

Key features

Custom operators

Unlike Java 8 streams, Lightweight-Stream-API provides the ability to apply custom operators.

Stream.of(...)
    .custom(new Reverse<>())
    .forEach(...);

public final class Reverse<T> implements UnaryOperator<Stream<T>> {

    @Override
    public Stream<T> apply(Stream<T> stream) {
        final Iterator<? extends T> iterator = stream.getIterator();
        final ArrayDeque<T> deque = new ArrayDeque<T>();
        while (iterator.hasNext()) {
            deque.addFirst(iterator.next());
        }
        return Stream.of(deque.iterator());
    }
}

You can find more examples here.

Additional operators

In addition to backported Java 8 Stream operators, the library provides:

  • filterNot - negated filter operator

    // Java 8
    stream.filter(((Predicate<String>) String::isEmpty).negate())
    // LSA
    stream.filterNot(String::isEmpty)
  • select - filters instances of the given class

    // Java 8
    stream.filter(Integer.class::isInstance)
    // LSA
    stream.select(Integer.class)
  • withoutNulls - filters only not null elements

    Stream.of("a", null, "c", "d", null)
        .withoutNulls() // [a, c, d]
  • sortBy - sorts by extractor function

    // Java 8
    stream.sorted(Comparator.comparing(Person::getName))
    // LSA
    stream.sortBy(Person::getName)
  • groupBy - groups by extractor function

    // Java 8
    stream.collect(Collectors.groupingBy(Person::getName)).entrySet().stream()
    // LSA
    stream.groupBy(Person::getName)
  • chunkBy - partitions sorted stream by classifier function

    Stream.of("a", "b", "cd", "ef", "gh", "ij", "klmnn")
        .chunkBy(String::length) // [[a, b], [cd, ef, gh, ij], [klmnn]]
  • sample - emits every n-th elements

    Stream.rangeClosed(0, 10)
        .sample(2) // [0, 2, 4, 6, 8, 10]
  • slidingWindow - partitions stream into fixed-sized list and sliding over the elements

    Stream.rangeClosed(0, 10)
        .slidingWindow(4, 6) // [[0, 1, 2, 3], [6, 7, 8, 9]]
  • takeWhile / dropWhile - introduced in Java 9, limits/skips stream by predicate function

    Stream.of("a", "b", "cd", "ef", "g")
        .takeWhile(s -> s.length() == 1) // [a, b]
    Stream.of("a", "b", "cd", "ef", "g")
        .dropWhile(s -> s.length() == 1) // [cd, ef, g]
  • scan - iteratively applies accumulation function and returns Stream

    IntStream.range(1, 6)
        .scan((a, b) -> a + b) // [1, 3, 6, 10, 15]
  • indexed - adds an index to every element, result is IntPair

    Stream.of("a", "b", "c")
        .indexed() // [(0 : "a"), (1 : "b"), (2 : "c")]
  • filterIndexed / mapIndexed / takeWhileIndexed / takeUntilIndexed / dropWhileIndexed / reduceIndexed / forEachIndexed - indexed specialization of operators

    Stream.of("a", "b", "c")
        .mapIndexed((i, s) -> s + Integer.toString(i)) // [a0, b1, c2]

Throwable functions

No more ugly try/catch in lambda expressions.

// Java 8
stream.map(file -> {
    try {
        return new FileInputStream(file);
    } catch (IOException ioe) {
        return null;
    }
})
// LSA
stream.map(Function.Util.safe(FileInputStream::new))

Download

Download latest release or grab via Maven:

<dependency>
  <groupId>com.annimon</groupId>
  <artifactId>stream</artifactId>
  <version>1.2.2</version>
</dependency>

or Gradle:

dependencies {
  ...
  implementation 'com.annimon:stream:1.2.2'
  ...
}

or use latest unrealeased features with JitPack.

Also included version for Java ME. Checkout javame branch.

Versions

Version
1.2.2
1.2.1
1.2.0
1.1.9
1.1.8
1.1.7
1.1.6
1.1.5
1.1.4
1.1.3
1.1.2
1.1.1
1.0.1
1.0.0