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The library of laconic method-aliases for safety stream operations with collections in Java

Java 100.00%

stream-utils's Introduction

Laconic Stream Utils

This is a library of laconic method-aliases for safety stream operations with collections in Java.

Introduction

Java 8+ introduces Stream API & Optional classes, but sometimes the syntax is really verbose even for simple stream manipulations. This library introduces method-aliases for some popular operation with collections.

For example, instead of the following code that maps users to modifiable list:

if (users != null) {
    return users.stream().map(User::getFirstName).collect(Collectors.toList());
}
return new ArrayList<>();

you can use short static method from the Lists class:

return map(users, User::getFirstName);

Installation

Min Requirements: JDK 8+

You can pull releases from the Maven Central repository: https://search.maven.org/artifact/io.github.avegera/stream-utils

Use the following dependency for Maven/Gradle:

Maven

<dependency>
    <groupId>io.github.avegera</groupId>
    <artifactId>stream-utils</artifactId>
    <version>0.3.0</version>
</dependency>

Gradle

implementation 'io.github.avegera:stream-utils:0.3.0'

Links

User Guide - TBD
JavaDoc
Wiki Documentation

Streams

Streams contains NPE-safety methods for stream instantiating by provided input data. For example, the following method returns stream of users (or empty stream in case when users == null):

Stream<User> stream = safeStream(users);

Lists

Lists contains NPE-safety method-aliases for common Stream API intermediate operations like:

map()
filter()
flatMap()
distinct()
sort()

By default, the result of operations is a List. Use suffix …ToSet() in method name to return Set instead. For example, the following method returns list of groups:

List<Group> groups = map(users, User::getGroup);

But this one returns set of groups:

Set<Group> groups = mapToSet(users, User::getGroup);

Aliases for terminal operations also available:

collect(toList())
collect(toSet())
count()
findFirst()
findAny()
allMatch()
anyMatch()
noneMatch()

For example, the following method returns first user from list or null if no users inside:

User user = findFirstOrNull(users);

License

This project is published under the Apache License 2.0, see http://www.apache.org/licenses/LICENSE-2.0 for details.

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stream-utils's Issues

Add findFirstOrNull() and findAnyOrNull() methods to StreamUtils

Two new methods should be introduced to StreamUtils class:

T findFirstOrNull(Collection collection)
T findAnyOrNull(Collection collection)

The ADR about method grouping criteria should be specified

code coverage quality gates should be added to the build
minimal value for class coverage should be >90%

Library API changes (including breaking changes)
Internal enhancements (documentation, ADRs, build changes, etc.)

String joinToString(Collection<?> collection, String delimiter);

Structure methods by output result type (according ADR-2)

Introduce predicates

Introduce predicate builder with the following syntax:

where(ApplicationDto::name).eq(value);

where(ApplicationDto::name).notIn(namesForRemoval);

Initial maven-module structure should be introduced

Introduce safe stream util-methods

The

AC:

Class StreamUtils.java with private constructor should be created.
Methods safeStream() with the following functionallity:
All introduced methods should be covered with unit-tests.
No new maven-dependencies should be added.

Sort method in classes in alphabetical order

Minor change to make consistent method order in classes.