Java Lambda - Consumer andThen example

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Consumer andThen returns a composed Consumer that performs, in sequence, for the current operation followed by the after operation.

Syntax

andThen has the following syntax.

default Consumer<T> andThen(Consumer<? super T> after)

Example

The following example shows how to use andThen.

import java.util.function.Consumer;

public class Main {
  public static void main(String[] args) {
    Consumer<String> c = (x) -> System.out.println(x.toLowerCase());
    c.andThen(c).accept("Java2s.com");
  }
}

The code above generates the following result.

Example 2

The following code shows how to chain Consumer to chain actions.

/*from   w  w  w  .java2 s.  c  o  m*/
import java.util.Arrays;
import java.util.List;
import java.util.function.Consumer;

public class Main {
  public static void main(String[] args) {
    List<Student> students = Arrays.asList(
        new Student(1, 3, "John"),
        new Student(2, 4, "Jane"), 
        new Student(3, 3,"Jack"));

    Consumer<Student> raiser = e -> {
      e.gpa = e.gpa * 1.1;
    };

    raiseStudents(students, System.out::println);
    raiseStudents(students, raiser.andThen(System.out::println));
  }

  private static void raiseStudents(List<Student> employees,
      Consumer<Student> fx) {
    for (Student e : employees) {
      fx.accept(e);
    }
  }

}

class Student {
  public int id;
  public double gpa;
  public String name;

  Student(int id, long g, String name) {
    this.id = id;
    this.gpa = g;
    this.name = name;
  }

  @Override
  public String toString() {
    return id + ">" + name + ": " + gpa;
  }
}

The code above generates the following result.

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