Object-Oriented Java Primitives

Project architect: @victornoel

Cactoos is a collection of object-oriented Java primitives.

We are not happy with JDK, Guava, and Apache Commons because they are procedural and not object-oriented. They do their job, but mostly through static methods. Cactoos is suggesting to do almost exactly the same, but through objects.

These are the design principles behind Cactoos.

The library has no dependencies. All you need is this:

Maven:

xml

<dependency>
  <groupId>org.cactoos</groupId>
  <artifactId>cactoos</artifactId>
  <version>0.57.0</version>
</dependency>

Gradle:

groovy

dependencies {
  compile 'org.cactoos:cactoos::0.57.0'
}

Java version required: 1.8+.

StackOverflow tag is cactoos.

Input/Output

More about it here: Object-Oriented Declarative Input/Output in Cactoos.

To read a text file in UTF-8:

java

String text = new TextOf(
  new File("/code/a.txt")
).asString();

To write a text into a file:

java

new LengthOf(
  new TeeInput(
    "Hello, world!",
    new File("/code/a.txt")
  )
).value();

To read a binary file from classpath:

java

byte[] data = new BytesOf(
  new ResourceOf("foo/img.jpg")
).asBytes();

Text/Strings

To format a text:

java

String text = new FormattedText(
  "How are you, %s?",
  name
).asString();

To manipulate text:

java

// To lower case
new Lowered(
  new TextOf("Hello")
);
// To upper case
new Upper(
  new TextOf("Hello")
);

Iterables/Collections/Lists/Sets

More about it here: Lazy Loading and Caching via Sticky Cactoos Primitives.

To filter a collection:

java

Collection<String> filtered = new ListOf<>(
  new Filtered<>(
    s -> s.length() > 4,
    new IterableOf<>("hello", "world", "dude")
  )
);

To flatten one iterable:

java

new Joined<>(
  new Mapped<IterableOf<>>(
    iter -> new IterableOf<>(
      new ListOf<>(iter).toArray(new Integer[]{})
    ),
    new IterableOf<>(1, 2, 3, 4, 5, 6)
  )
);    // Iterable<Integer>

To flatten and join several iterables:

java

new Joined<>(
  new Mapped<IterableOf<>>(
    iter -> new IterableOf<>(
      new Joined<>(iter)
    ),
    new Joined<>(
      new IterableOf<>(new IterableOf<>(1, 2, 3)),
      new IterableOf<>(new IterableOf<>(4, 5, 6))
    )
  )
);    // Iterable<Integer>

To iterate a collection:

java

new And(
  new Mapped<>(
    new FuncOf<>(
      input -> {
        System.out.printf("Item: %s\n", input);
      },
      new True()
    ),
    new IterableOf<>("how", "are", "you", "?")
  )
).value();

Or even more compact:

java

new ForEach<>(
  input -> System.out.printf(
    "Item: %s\n", input
  )
).exec(new IterableOf<>("how", "are", "you", "?"));

To sort a list of words in the file:

java

List<Text> sorted = new ListOf<>(
  new Sorted<>(
    new Mapped<>(
      text -> new ComparableText(text),
      new Split(
        new TextOf(
          new File("/tmp/names.txt")
        ),
        new TextOf("\\s+")
      )
    )
  )
);

To count elements in an iterable:

java

int total = new LengthOf(
  new IterableOf<>("how", "are", "you")
).value().intValue();

To create a set of elements by providing variable arguments:

java

final Set<String> unique = new SetOf<>(
  "one",
  "two",
  "one",
  "three"
);

To create a set of elements from an existing iterable:

java

final Set<String> words = new SetOf<>(
  new IterableOf<>("abc", "bcd", "abc", "ccc")
);

To create a sorted iterable with unique elements from an existing iterable:

java

final Iterable<String> sorted = new Sorted<>(
  new SetOf<>(
    new IterableOf<>("abc", "bcd", "abc", "ccc")
  )
);

To create a sorted set from existing vararg elements using a comparator:

java

final Set<String> sorted = new org.cactoos.set.Sorted<>(
  (first, second) -> first.compareTo(second),
  "abc", "bcd", "abc", "ccc", "acd"
);

To create a sorted set from an existing iterable using a comparator:

java

final Set<String> sorted = new org.cactoos.set.Sorted<>(
  (first, second) -> first.compareTo(second),
  new IterableOf<>("abc", "bcd", "abc", "ccc", "acd")
);

Funcs and Procs

This is a traditional foreach loop:

java

for (String name : names) {
  System.out.printf("Hello, %s!\n", name);
}

This is its object-oriented alternative (no streams!):

java

new And(
  n -> {
    System.out.printf("Hello, %s!\n", n);
    return new True().value();
  },
  names
).value();

This is an endless while/do loop:

java

while (!ready) {
  System.out.println("Still waiting...");
}

Here is its object-oriented alternative:

java

new And(
  ready -> {
    System.out.println("Still waiting...");
    return !ready;
  },
  new Endless<>(booleanParameter)
).value();

Dates and Times

From our org.cactoos.time package.

Our classes are divided in two groups: those that parse strings into date/time objects, and those that format those objects into strings.

For example, this is the traditional way of parsing a string into an OffsetDateTime:

java

final OffsetDateTime date = OffsetDateTime.parse("2007-12-03T10:15:30+01:00");

Here is its object-oriented alternative (no static method calls!) using OffsetDateTimeOf, which is a Scalar:

java

final OffsetDateTime date = new OffsetDateTimeOf("2007-12-03T10:15:30+01:00").value();

To format an OffsetDateTime into a Text:

java

final OffsetDateTime date = ...;
final String text = new TextOfDateTime(date).asString();

Our Objects vs. Their Static Methods

Cactoos	Guava	Apache Commons	JDK 8
`And`	`Iterables.all()`	-	-
`Filtered`	`Iterables.filter()`	?	-
`FormattedText`	-	-	`String.format()`
`IsBlank`	-	`StringUtils.isBlank()`	-
`Joined`	-	-	`String.join()`
`LengthOf`	-	-	`String#length()`
`Lowered`	-	-	`String#toLowerCase()`
`Normalized`	-	`StringUtils.normalize()`	-
`Or`	`Iterables.any()`	-	-
`Repeated`	-	`StringUtils.repeat()`	-
`Replaced`	-	-	`String#replace()`
`Reversed`	-	-	`StringBuilder#reverse()`
`Rotated`	-	`StringUtils.rotate()`	-
`Split`	-	-	`String#split()`
`StickyList`	`Lists.newArrayList()`	?	`Arrays.asList()`
`Sub`	-	-	`String#substring()`
`SwappedCase`	-	`StringUtils.swapCase()`	-
`TextOf`	?	`IOUtils.toString()`	-
`TrimmedLeft`	-	`StringUtils.stripStart()`	-
`TrimmedRight`	-	`StringUtils.stripEnd()`	-
`Trimmed`	-	`StringUtils.stripAll()`	`String#trim()`
`Upper`	-	-	`String#toUpperCase()`

Questions

Ask your questions related to cactoos library on Stackoverflow with the cactoos tag.

How to Contribute

Just fork the repo and send us a pull request.

Make sure your branch builds without any warnings/issues:

bash

mvn clean verify -Pqulice

To run a build similar to the CI with Docker only, use:

bash

docker run \
  --tty \
  --interactive \
  --workdir=/main \
  --volume=${PWD}:/main \
  --volume=cactoos-mvn-cache:/root/.m2 \
  --rm \
  maven:3-jdk-8 \
  bash -c "mvn clean install -Pqulice; chown -R $(id -u):$(id -g) target/"

To remove the cache used by Docker-based build:

bash

docker volume rm cactoos-mvn-cache

Note: Checkstyle is used as a static code analysis tool with checks list in GitHub precommits.

Contributors

@yegor256 as Yegor Bugayenko (Blog)
@g4s8 as Kirill Che.
@fabriciofx as Fabrício Cabral
@englishman as Andriy Kryvtsun
@VsSekorin as Vseslav Sekorin
@DronMDF as Andrey Valyaev
@dusan-rychnovsky as Dušan Rychnovský (Blog)
@timmeey as Tim Hinkes (Blog)
@alex-semenyuk as Alexey Semenyuk
@smallcreep as Ilia Rogozhin
@memoyil as Mehmet Yildirim
@llorllale as George Aristy
@driver733 as Mikhail Yakushin
@izrik as Richard Sartor
@Vatavuk as Vedran Grgo Vatavuk
@dgroup as Yurii Dubinka
@iakunin as Maksim Iakunin
@fanifieiev as Fevzi Anifieiev
@victornoel as Victor Noël
@paulodamaso as Paulo Lobo

cactoos

Object-Oriented Java Primitives

Input/Output

Text/Strings

Iterables/Collections/Lists/Sets

Funcs and Procs

Dates and Times

Our Objects vs. Their Static Methods

Questions

How to Contribute

Contributors

Command Palette