CollectorsTest.java 文件源码

@Test
public void immutableMultiMapCollector() {
    ImmutableMultimap<Integer, Integer> result = Stream.iterate(0, p -> p+1)
            .parallel()
            .limit(GENERATED_ITEMS)
            .collect(Collectors.groupingBy(i -> i % 10));

    assertEquals(GENERATED_ITEMS,result.size());
    assertEquals(10,result.asMap().size());
    for (int i=0;i<10;i++) {
        int key=i;
        ImmutableCollection<Integer> values = result.get(key);
        values.forEach(v -> {
            assertEquals(key,v % 10);
        });
    }
}