MultimapsTest.java 文件源码

public void testFlatteningToMultimap() {
  Collector<String, ?, ListMultimap<Character, Character>> collector =
      Multimaps.flatteningToMultimap(
          str -> str.charAt(0),
          str -> str.substring(1).chars().mapToObj(c -> (char) c),
          MultimapBuilder.linkedHashKeys().arrayListValues()::build);
  BiPredicate<Multimap<?, ?>, Multimap<?, ?>> equivalence =
      Equivalence.equals()
          .onResultOf((Multimap<?, ?> mm) -> ImmutableList.copyOf(mm.asMap().entrySet()))
          .and(Equivalence.equals());
  ListMultimap<Character, Character> empty =
      MultimapBuilder.linkedHashKeys().arrayListValues().build();
  ListMultimap<Character, Character> filled =
      MultimapBuilder.linkedHashKeys().arrayListValues().build();
  filled.putAll('b', Arrays.asList('a', 'n', 'a', 'n', 'a'));
  filled.putAll('a', Arrays.asList('p', 'p', 'l', 'e'));
  filled.putAll('c', Arrays.asList('a', 'r', 'r', 'o', 't'));
  filled.putAll('a', Arrays.asList('s', 'p', 'a', 'r', 'a', 'g', 'u', 's'));
  filled.putAll('c', Arrays.asList('h', 'e', 'r', 'r', 'y'));
  CollectorTester.of(collector, equivalence)
      .expectCollects(empty)
      .expectCollects(filled, "banana", "apple", "carrot", "asparagus", "cherry");
}