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https://github.com/rubenjgarcia/commons-functional

A collection of Functional helpers for Java 8
https://github.com/rubenjgarcia/commons-functional
functional functional-programming java-8 tuples
Last synced: 9 days ago
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A collection of Functional helpers for Java 8
Host: GitHub
URL: https://github.com/rubenjgarcia/commons-functional
Owner: rubenjgarcia
License: mit
Created: 2016-10-07T15:31:34.000Z (over 8 years ago)
Default Branch: dev
Last Pushed: 2017-03-24T11:56:44.000Z (almost 8 years ago)
Last Synced: 2024-11-15T04:48:39.437Z (2 months ago)
Topics: functional, functional-programming, java-8, tuples
Language: Java
Homepage:
Size: 33.2 KB
Stars: 3
Watchers: 4
Forks: 1
Open Issues: 0
Metadata Files:
- Readme: README.md
- License: LICENSE
Awesome Lists containing this project

README

        # Commons functional

A collection of Functional helpers

## Tuples

From 1 to 10 fields

```

import es.rubenjgarcia.commons.functional.tuple.*;

import static es.rubenjgarcia.commons.functional.tuple.Tuple.tuple;

Tuple2 t2 = tuple("1", "2");

t2.toString(); // (1, 2)

t2.equals(tuple("1", "2")); // true

```

## Stream Utils

### zip

Returns a list of [Tuple2](src/main/java/es/rubenjgarcia/commons/functional/tuple/Tuple2.java) formed from two streams by combining corresponding elements in pairs. If one of the two collections is longer than the other, its remaining elements are ignored.

```

import static es.rubenjgarcia.commons.functional.StreamUtils.zip;

List ints = Arrays.asList(1, 2, 3);

List strings = Arrays.asList("a", "b", "c");

List> tuples = zip(ints.stream(), strings.stream()).collect(Collectors.toList());

tuples.toString(); // [(1, a), (2, b), (3, c)]

```

### zipWithIndex

```

import static es.rubenjgarcia.commons.functional.StreamUtils.zipWithIndex;

List strings = Arrays.asList("1", "2", "3");

List> tuples = zipWithIndex(strings.stream()).collect(Collectors.toList());

```

### unzip

Converts a collection of [Tuple2](src/main/java/es/rubenjgarcia/commons/functional/tuple/Tuple2.java) into a [Tuple2](src/main/java/es/rubenjgarcia/commons/functional/tuple/Tuple2.java) of stream of the first and second half of each pair

```

import es.rubenjgarcia.commons.functional.tuple.*;

import static es.rubenjgarcia.commons.functional.StreamUtils.unzip;

Tuple2, Stream> tupleStream = unzip(tuples);

List ints = tupleStream._1.collect(Collectors.toList());

List strings = tupleStream._2.collect(Collectors.toList());

```

## Functional Filters

### anyOf

Return if the value matches any predicate

```

import static es.rubenjgarcia.commons.functional.FunctionalFilters.anyOf;

Predicate p = anyOf(n -> n == 1, n -> n == 2);

p.test(1); // true

p.test(3); // false

```

### noneOf

Return if the value doesn't match any of the predicates

```

import static es.rubenjgarcia.commons.functional.FunctionalFilters.noneOf;

Predicate p = noneOf(n -> n == 1, n -> n == 2);

p.test(1); // false

p.test(3); // true

```

### allOf

Return if the value matches all the predicates

```

import static es.rubenjgarcia.commons.functional.FunctionalFilters.allOf;

Predicate p = allOf(n -> n > 1, n -> n < 3);

p.test(1); // false

p.test(2); // true

```

### findFirst

Find the first element that matchs the predicate

```

import static es.rubenjgarcia.commons.functional.FunctionalFilters.findFirst;

Optional found = findFirst(Stream.of(1, 2), n -> n == 1);

found.isPresent(); // true

found.get(); 1

```

### findLast

Finds the last element that matchs the predicate

```

import static es.rubenjgarcia.commons.functional.FunctionalFilters.findLast;

Optional last = findLast(Stream.of(1, 2, 3), p -> p > 1 && p <= 2);

last.isPresent(); // true

last.get(); // 2

```

### findFirstNotMatch

Finds first element that doesn't match the predicate

```

import static es.rubenjgarcia.commons.functional.FunctionalFilters.findFirstNotMatch;

Optional found = findFirstNotMatch(Stream.of(1, 2), n -> n == 1);

found.isPresent(); // true

found.get(); // 2

```

## FlowStream

### mapIf

Apply a map function to the element of a stream if the element matches the predicate

```

import static es.rubenjgarcia.commons.functional.FlowStream.mapIf;

List list = Arrays.asList(1, 1, 1, 1);

List result = mapIf(list::stream, i -> i == 1, i -> "A")

        .collect(Collectors.toList()); // [A, A, A, A]

```

```

List list = Arrays.asList(1, 2, 2, 1);

List result = mapIf(list::stream, i -> i == 1, i -> "A")

        .collect(Collectors.toList()); // [A, 2, 2, A]

```

### elseIfMap

Apply a map function to the element of a stream if the element matches the predicate after a mapIf code

```

import static es.rubenjgarcia.commons.functional.FlowStream.mapIf;

List list = Arrays.asList(1, 2, 3, 1);

List result = mapIf(list::stream, i -> i == 1, i -> "A")

        .elseIfMap(i -> i == 2, i -> "B")

        .collect(Collectors.toList()); // [A, B, 3, A]

```

```

import static es.rubenjgarcia.commons.functional.FlowStream.mapIf;

List list = Arrays.asList(1, 2, 3, 1);

List result = mapIf(list::stream, i -> i == 1, i -> "A")

        .elseIfMap(i -> i == 2, i -> "B")

        .elseIfMap(i -> i == 3, i -> "C")

        .collect(Collectors.toList()); // [A, B, C, A]

```

### elseMap

Apply a map function to the elements of a stream that don't match any of the other if or elseif predicates

```

import static es.rubenjgarcia.commons.functional.FlowStream.mapIf;

List list = Arrays.asList(1, 2, 3, 1);

List result = mapIf(list::stream, i -> i == 1, i -> "A")

        .elseIfMap(i -> i == 2, i -> "B")

        .elseMap(i -> "C")

        .collect(Collectors.toList()); // [A, B, C, A]

```

```

import static es.rubenjgarcia.commons.functional.FlowStream.mapIf;

List list = Arrays.asList(1, 2, 3, 1);

List result = mapIf(list::stream, i -> i == 1, i -> "A")

        .elseMap(i -> "C")

        .collect(Collectors.toList()); // [A, C, C, A]

```

### mapIfAny

Apply a map function to all the elements of the stream if any of them match the predicate

```

import static es.rubenjgarcia.commons.functional.FlowStream.mapIfAny;

List list = Arrays.asList(1, 2, 2, 1);

List result = mapIfAny(list::stream, i -> i == 1, i -> "A")

        .collect(Collectors.toList()); // [A, A, A, A]

```

### elseIfAnyMap

Apply a map function to all the elements of the stream if any of them match the predicate and don't match the other predicates

```

import static es.rubenjgarcia.commons.functional.FlowStream.mapIfAny;

List list = Arrays.asList(1, 1, 1, 1);

List result = mapIfAny(list::stream, i -> i == 2, i -> "A")

        .elseIfAnyMap(i -> i == 1, i -> "B")

        .collect(Collectors.toList()); // [B, B, B, B]

```

```

import static es.rubenjgarcia.commons.functional.FlowStream.mapIfAny;

List list = Arrays.asList(1, 2, 3, 1);

List result = mapIfAny(list::stream, i -> i == 2, i -> "A")

        .elseIfAnyMap(i -> i == 4, i -> "B")

        .elseIfAnyMap(i -> i == 1, i -> "C")

        .collect(Collectors.toList()); // [C, C, C, C]

```

You can combine any of the flows

```

import static es.rubenjgarcia.commons.functional.FlowStream.mapIf;

List list = Arrays.asList(1, 2, 1, 1);

List result = mapIf(list::stream, i -> i == 2, i -> "A")

        .elseIfAnyMap(i -> i == 1, i -> "B")

        .elseMap(i -> "C")

        .collect(Collectors.toList()); // [B, A, B, B]

```

## Exceptions 

You can use `rethrowFunction`, `rethrowBiFunction`, `rethrowConsumer`, `rethrowBiConsumer`, `rethrowPredicate`, `rethrowBiPredicate` or `rethrowSupplier` to deal with [Function](https://docs.oracle.com/javase/8/docs/api/java/util/function/Function.html), [BiFunction](https://docs.oracle.com/javase/8/docs/api/java/util/function/BiFunction.html), [Consumer](https://docs.oracle.com/javase/8/docs/api/java/util/function/Consumer.html), [BiConsumer](https://docs.oracle.com/javase/8/docs/api/java/util/function/BiConsumer.html), [Predicate](https://docs.oracle.com/javase/8/docs/api/java/util/function/Predicate.html), [BiPredicate](https://docs.oracle.com/javase/8/docs/api/java/util/function/BiPredicate.html) or [Supplier](https://docs.oracle.com/javase/8/docs/api/java/util/function/Supplier.html) that throws any checked [Exception](https://docs.oracle.com/javase/8/docs/api/java/lang/Exception.html) 

```

import static es.rubenjgarcia.commons.functional.FunctionalExceptions.rethrowFunction;

Stream.of("a", "b").map(rethrowFunction(s -> new String(s.getBytes(), "Foo")));

```

```

import static es.rubenjgarcia.commons.functional.FunctionalExceptions.rethrowBiFunction;

Map map = new HashMap<>();

map.put("a", "b");

map.replaceAll(rethrowBiFunction((k, v) -> new String(k.getBytes(), "Foo")))

```

```

import static es.rubenjgarcia.commons.functional.FunctionalExceptions.rethrowConsumer;

Stream.of("a", "b").forEach(rethrowConsumer(s -> new String(s.getBytes(), "Foo")));

```

```

import static es.rubenjgarcia.commons.functional.FunctionalExceptions.rethrowBiConsumer;

Map map = new HashMap<>();

map.put("a", "b");

map.forEach(rethrowBiConsumer((k, v) -> new String(k.getBytes(), "Foo")));

```

```

import static es.rubenjgarcia.commons.functional.FunctionalExceptions.rethrowPredicate;

Stream.of("a", "b").filter(rethrowPredicate(s -> new String(s.getBytes(), "Foo") == null));

```

```

import static es.rubenjgarcia.commons.functional.FunctionalExceptions.rethrowBiPredicate;

BiPredicate predicate = rethrowBiPredicate((s, e) -> new String(s.getBytes(), e).isEmpty());

predicate.test("a", "Foo");

```

```

import static es.rubenjgarcia.commons.functional.FunctionalExceptions.rethrowSupplier;

rethrowPredicate(() -> new String(s.getBytes(), "Foo"));

```

# Installation

Just add to your pom.xml

```

    es.rubenjgarcia

    commons-functional

    0.2.0

```