Enums example

Setup

enum Day {

    SUNDAY, MONDAY, TUESDAY, WEDNESDAY,
    THURSDAY, FRIDAY, SATURDAY
}

Get field

@Test
public void enums_getfield () {

    Field field = Enums.getField(Day.FRIDAY);

    assertTrue(field.isEnumConstant());
}

Get if present

@Test
public void enums_getIfPresent () {

    Optional<Day> friday = Enums.getIfPresent(Day.class, "FRIDAY");

    assertEquals(friday.get(), Day.FRIDAY);
}

Value of function

@Test
public void enums_valueOfFunction () {

    Function<String, Day> valueOfFunction = Enums.valueOfFunction(Day.class);

    Day friday = valueOfFunction.apply("FRIDAY");

    assertEquals(friday, Day.FRIDAY);
}

Transform string to enum

@Test
public void transform_string_to_enum () {

    List<String> days = Lists.newArrayList(
            "WEDNESDAY",
            "SUNDAY",
            "MONDAY",
            "TUESDAY",
            "WEDNESDAY");

    Function<String, Day> valueOfFunction = Enums.valueOfFunction(Day.class);

    Iterable<Day> daysAsEnums = Iterables.transform(days, valueOfFunction);

    assertThat(daysAsEnums, IsIterableWithSize.<Day>iterableWithSize(5));
    assertThat(daysAsEnums, IsIterableContainingInOrder.
            <Day>contains(
                    Day.WEDNESDAY,
                    Day.SUNDAY,
                    Day.MONDAY,
                    Day.TUESDAY,
                    Day.WEDNESDAY));

}

String conveter

@Test
public void transform_string_to_enum_string_converter () {

    List<String> days = Lists.newArrayList(
            "WEDNESDAY",
            "SUNDAY",
            "MONDAY",
            "TUESDAY",
            "WEDNESDAY");

    Function<String, Day> valueOfFunction = Enums.stringConverter(Day.class);

    Iterable<Day> daysAsEnums = Iterables.transform(days, valueOfFunction);

    assertThat(daysAsEnums, IsIterableWithSize.<Day>iterableWithSize(5));
    assertThat(daysAsEnums, IsIterableContainingInOrder.
            <Day>contains(
                    Day.WEDNESDAY,
                    Day.SUNDAY,
                    Day.MONDAY,
                    Day.TUESDAY,
                    Day.WEDNESDAY));
}