Let's start with the filter operation. Filters is a function with a self-explanatory name; it filters in/out elements in the stream depending on whether the value satisfies a condition, as shown in the following example:
@Testpublic void filterByNameReturnsCollectionFiltered() { List<String> names = Arrays.asList("Alex", "Paul", "Viktor", "Kobe", "Tom", "Andrea"); List<String> filteredNames = Collections.emptyList(); assertThat(filteredNames) .hasSize(2) .containsExactlyInAnyOrder("Alex", "Andrea");}
One possibility for computing the list of filteredNames is the following:
List<String> filteredNames = names.stream() .filter(name -> name.startsWith("A")) .collect(Collectors.toList());
That one is the easiest. In a few words, filter ...
