test/java/util/Optional/Basic.java

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rev 7596 : 8015317: Optional.filter, map, and flatMap
Reviewed-by:
Contributed-by: brian.goetz@oracle.com, henry.jen@oracle.com


  97         assertTrue(present.equals(Optional.of(Boolean.TRUE)));
  98         assertTrue(!present.equals(empty));
  99         assertTrue(Boolean.TRUE.hashCode() == present.hashCode());
 100         assertTrue(!present.toString().isEmpty());
 101         assertTrue(!present.toString().equals(presentEmptyString.toString()));
 102         assertTrue(-1 != present.toString().indexOf(Boolean.TRUE.toString()));
 103         assertSame(Boolean.TRUE, present.get());
 104         try {
 105             present.ifPresent(v -> { throw new ObscureException(); });
 106             fail();
 107         } catch(ObscureException expected) {
 108 
 109         }
 110         assertSame(Boolean.TRUE, present.orElse(null));
 111         assertSame(Boolean.TRUE, present.orElse(Boolean.FALSE));
 112         assertSame(Boolean.TRUE, present.orElseGet(null));
 113         assertSame(Boolean.TRUE, present.orElseGet(()-> null));
 114         assertSame(Boolean.TRUE, present.orElseGet(()-> Boolean.FALSE));
 115         assertSame(Boolean.TRUE, present.<RuntimeException>orElseThrow( null));
 116         assertSame(Boolean.TRUE, present.<RuntimeException>orElseThrow(ObscureException::new));














































































































 117     }
 118 
 119     private static class ObscureException extends RuntimeException {
 120 
 121     }
 122 }


  97         assertTrue(present.equals(Optional.of(Boolean.TRUE)));
  98         assertTrue(!present.equals(empty));
  99         assertTrue(Boolean.TRUE.hashCode() == present.hashCode());
 100         assertTrue(!present.toString().isEmpty());
 101         assertTrue(!present.toString().equals(presentEmptyString.toString()));
 102         assertTrue(-1 != present.toString().indexOf(Boolean.TRUE.toString()));
 103         assertSame(Boolean.TRUE, present.get());
 104         try {
 105             present.ifPresent(v -> { throw new ObscureException(); });
 106             fail();
 107         } catch(ObscureException expected) {
 108 
 109         }
 110         assertSame(Boolean.TRUE, present.orElse(null));
 111         assertSame(Boolean.TRUE, present.orElse(Boolean.FALSE));
 112         assertSame(Boolean.TRUE, present.orElseGet(null));
 113         assertSame(Boolean.TRUE, present.orElseGet(()-> null));
 114         assertSame(Boolean.TRUE, present.orElseGet(()-> Boolean.FALSE));
 115         assertSame(Boolean.TRUE, present.<RuntimeException>orElseThrow( null));
 116         assertSame(Boolean.TRUE, present.<RuntimeException>orElseThrow(ObscureException::new));
 117     }
 118 
 119     @Test(groups = "unit")
 120     public void testOfNullable() {
 121         Optional<String> instance = Optional.ofNullable(null);
 122         assertFalse(instance.isPresent());
 123 
 124         instance = Optional.ofNullable("Duke");
 125         assertTrue(instance.isPresent());
 126         assertEquals(instance.get(), "Duke");
 127     }
 128 
 129     @Test(groups = "unit")
 130     public void testFilter() {
 131         // Null mapper function
 132         Optional<String> empty = Optional.empty();
 133         Optional<String> duke = Optional.of("Duke");
 134 
 135         try {
 136             Optional<String> result = empty.filter(null);
 137             fail("Should throw NPE on null mapping function");
 138         } catch (NullPointerException npe) {
 139             // expected
 140         }
 141 
 142         Optional<String> result = empty.filter(String::isEmpty);
 143         assertFalse(result.isPresent());
 144 
 145         result = duke.filter(String::isEmpty);
 146         assertFalse(result.isPresent());
 147         result = duke.filter(s -> s.startsWith("D"));
 148         assertTrue(result.isPresent());
 149         assertEquals(result.get(), "Duke");
 150 
 151         Optional<String> emptyString = Optional.of("");
 152         result = emptyString.filter(String::isEmpty);
 153         assertTrue(result.isPresent());
 154         assertEquals(result.get(), "");
 155     }
 156 
 157     @Test(groups = "unit")
 158     public void testMap() {
 159         Optional<String> empty = Optional.empty();
 160         Optional<String> duke = Optional.of("Duke");
 161 
 162         // Null mapper function
 163         try {
 164             Optional<Boolean> b = empty.map(null);
 165             fail("Should throw NPE on null mapping function");
 166         } catch (NullPointerException npe) {
 167             // expected
 168         }
 169 
 170         // Map an empty value
 171         Optional<Boolean> b = empty.map(String::isEmpty);
 172         assertFalse(b.isPresent());
 173 
 174         // Map into null
 175         b = empty.map(n -> null);
 176         assertFalse(b.isPresent());
 177         b = duke.map(s -> null);
 178         assertFalse(b.isPresent());
 179 
 180         // Map to value
 181         Optional<Integer> l = duke.map(String::length);
 182         assertEquals(l.get().intValue(), 4);
 183     }
 184 
 185     @Test(groups = "unit")
 186     public void testFlatMap() {
 187         Optional<String> empty = Optional.empty();
 188         Optional<String> duke = Optional.of("Duke");
 189 
 190         // Null mapper function
 191         try {
 192             Optional<Boolean> b = empty.flatMap(null);
 193             fail("Should throw NPE on null mapping function");
 194         } catch (NullPointerException npe) {
 195             // expected
 196         }
 197 
 198         // Map into null
 199         try {
 200             Optional<Boolean> b = duke.flatMap(s -> null);
 201             fail("Should throw NPE when mapper return null");
 202         } catch (NullPointerException npe) {
 203             // expected
 204         }
 205 
 206         // Empty won't invoke mapper function
 207         try {
 208             Optional<Boolean> b = empty.flatMap(s -> null);
 209             assertFalse(b.isPresent());
 210         } catch (NullPointerException npe) {
 211             fail("Mapper function should not be invoked");
 212         }
 213 
 214         // Map an empty value
 215         Optional<Integer> l = empty.flatMap(s -> Optional.of(s.length()));
 216         assertFalse(l.isPresent());
 217 
 218         // Map to value
 219         Optional<Integer> fixture = Optional.of(Integer.MAX_VALUE);
 220         l = duke.flatMap(s -> Optional.of(s.length()));
 221         assertTrue(l.isPresent());
 222         assertEquals(l.get().intValue(), 4);
 223 
 224         // Verify same instance
 225         l = duke.flatMap(s -> fixture);
 226         assertSame(l, fixture);
 227     }
 228 
 229     private static class ObscureException extends RuntimeException {
 230 
 231     }
 232 }