Consumer Example in Java 8

 

Consumer Example in Java 8 

forEach in Iterable.java interface which uses Consumer: 

default void forEach(Consumer<? super T> action) 

{

    Objects.requireNonNull(action);

    for (T t : this) {

        action.accept(t);

    }

}

@FunctionalInterface
public interface Consumer<T>

Represents an operation that accepts a single input argument and returns no result. Unlike most other functional interfaces, Consumer is expected to operate via side-effects.

This is a functional interface whose functional method is accept(Object).

Method:

void accept(T t)

andThen
default Consumer<T> andThen(Consumer<? super T> after)
Returns a composed Consumer that performs, in sequence, this operation followed by the after operation. If performing either operation throws an exception, it is relayed to the caller of the composed operation. If performing this operation throws an exception, the after operation will not be performed.
Parameters:
after - the operation to perform after this operation
Returns:
a composed Consumer that performs in sequence this operation followed by the after operation
Throws:
NullPointerException - if after is null

Example:

import java.util.Arrays;

import java.util.List;

import java.util.function.Consumer;

public class ConsumerEx {

public static void main(String[] args) {

List<String> list = Arrays.asList("india", "uk", "fiji");

Consumer<String> consumer = (t) -> {

System.out.println(t.toUpperCase());

};

list.forEach(consumer);

}

}

Output:

INDIA

UK

FIJI