Java List Helpers

Useful library to work with Java Lists.

Maven Snippet

If you are using Maven, configure the following dependency in your pom.xml:

<dependency>
  <groupId>com.github.bicoco</groupId>
  <artifactId>java-list-helpers</artifactId>
  <version>1.3</version>
</dependency>

How to use this

The examples below use the import static:

import static com.github.bicoco.Helpers.*;

Suppose a simple class Person

public class Person {
  private String name;
  private Integer age;

  public Person(String name, Integer age) {
    this.name = name;
    this.age = age;
  }

  public String getName() {
    return name;
  }

  public Integer getAge() {
    return age;
  }
}

and a List of Person

ArrayList<Person> persons = new ArrayList<Person>();
persons.add(new Person("David", 27));
persons.add(new Person("André", 30));
persons.add(new Person("Fernando", 25));
persons.add(new Person("Lucas", 15));

With this library you can iterate like this:

each(persons, new EachFunction<Person>() {
    public void each(Person person) {
        System.out.println(person.getName());
    }
});

or transform it to a list of a different type:

List<Integer> ages = transform(persons, new TransformFunction<Person,Integer>() {
    public Integer transform(Person person) {
        return person.getAge();
    }
});

or select elements using a condition:

List<Person> personsGreaterThan18YearsOld = select(persons, new ConditionFunction<Person>() {
    public boolean condition(Person person) {
        return person.getAge() > 18;
    }
});

or transform all of the elements to a single value which can be of any type:

Integer result = reduce(people, 0, new ReduceFunction<Person, Integer>() {
    public Integer reduce(Integer memo, Person person) {
        return memo += person.getAge();
    }
});

There are many other features but for now you can see more examples in the ListTest class.