java-examples (0.0.1)

public class Java7Predicate {

    public interface MyPredicate {
        boolean test(final String value);
    }

    @RequiredArgsConstructor
    public static class Is implements MyPredicate {
        final String value;

        @Override
        public boolean test(String value) {
            return value != null && value.contains(this.value);
        }
    }

    public static class IsRed implements MyPredicate {
        @Override
        public boolean test(final String value) {
            return nonNull(value) && value.toLowerCase().contains("red");
        }
    }

    public static void sideEffect(final MyPredicate predicate) {
        final List<String> list = Arrays.asList("ololo", "trololo", "red", "blue", "green", "red devil");
        for (String i : list) {
            if (predicate.test(i)) {
                System.out.println("i = " + i);
            }
        }
    }
}

@Slf4j
@CaptureSystemOutput
@DisplayName("test predicate API: java 7")
class Java7PredicateTest {

    @Test
    @DisplayName("test positive")
    void testPredicate(final CaptureSystemOutput.OutputCapture outputCapture) {

        assertAll(() -> {

            sideEffect(new Java7Predicate.IsRed());
            Assertions.assertThat(outputCapture.toString())
                    .contains("i = red", "i = red devil");

            sideEffect(new Java7Predicate.Is("green"));
            Assertions.assertThat(outputCapture.toString().contains("t = green"));
        });
    }
}