jolice / xstream

Implementation of simplified version of Java Stream API

Stream

Implementation of simplified and modified version of Java Stream API with lazy evaluation.

Dependency

This project is distributed via JitPack. Register a JitPack repository at your pom.xml:

<repositories>
    <repository>
        <id>jitpack.io</id>
        <url>https://jitpack.io</url>
    </repository>
</repositories>

And add the following dependency:

<dependency>
    <groupId>com.github.jolice</groupId>
    <artifactId>Stream</artifactId>
    <version>v1.0</version>
</dependency>

Creating a stream

StreamFactory class is responsible for creating streams.

A stream may be constructed from fixed list of elements:

Stream<String> stream = StreamFactory.of("alpha", "bravo", "charlie", "delta", "echo");

Or from any Iterable implementation:

List<String> list = Arrays.asList("alpha", "bravo", "charlie", "delta", "echo");
Stream<String> stream = StreamFactory.of(list);

Empty stream may be created as follows:

Stream<String> stream = StreamFactory.empty();

Infinite streams are also supported:

Stream<Integer> stream = StreamFactory.iterate(1, i -> i + 1).limit(5);

Operations

Operations inherited from Java 8 Stream interface

• Iterator
• Filter
• Map
• FlatMap
• Distinct
• Sorted
• Peek
• Limit
• Skip
• ForEach
• ToArray
• Reduce
• Collect
• Min
• Max
• Count
• AnyMatch
• AllMatch
• NoneMatch
• FindAny

Custom operations

TakeWhile skips all elements after the first one that doesn't match a predicate:

StreamFactory.of(1,2,3,4,5,6).takeWhile(x -> x <= 3)
       .collect(Collectors.toList()); // [1,2,3]

DropWhile skips all elements before the first one that matches a predicate:

 StreamFactory.of(6,5,4,3,2,1).dropWhile(x -> x > 3)
       .collect(Collectors.toList()); // [3,2,1]

FiterNot filters out the elements that match the predicate, inverse for Filter:

StreamFactory.of(1,2,3,4,5,6).filterNot(x -> x % 2 == 0)
        .collect(Collectors.toList()); // [1,3,5]

FilterNulls filters out null items:

StreamFactory.of(1, 2, null, 4, null, 6).filterNulls()
        .collect(Collectors.toList()); // [1, 2, 4, 6]

Not supported operations

• Parallel
• MapToInt / Double / Long
• FlatMapToInt / Double / Long
• ForEachOrdered