src/share/classes/java/util/Objects.java

Print this page
rev 7044 : 8013712: Add Objects.nonNull and Objects.isNull
Reviewed-by: duke


 209      * constructors with multiple parameters, as demonstrated below:
 210      * <blockquote><pre>
 211      * public Foo(Bar bar, Baz baz) {
 212      *     this.bar = Objects.requireNonNull(bar, "bar must not be null");
 213      *     this.baz = Objects.requireNonNull(baz, "baz must not be null");
 214      * }
 215      * </pre></blockquote>
 216      *
 217      * @param obj     the object reference to check for nullity
 218      * @param message detail message to be used in the event that a {@code
 219      *                NullPointerException} is thrown
 220      * @param <T> the type of the reference
 221      * @return {@code obj} if not {@code null}
 222      * @throws NullPointerException if {@code obj} is {@code null}
 223      */
 224     public static <T> T requireNonNull(T obj, String message) {
 225         if (obj == null)
 226             throw new NullPointerException(message);
 227         return obj;
 228     }




































 229 }


 209      * constructors with multiple parameters, as demonstrated below:
 210      * <blockquote><pre>
 211      * public Foo(Bar bar, Baz baz) {
 212      *     this.bar = Objects.requireNonNull(bar, "bar must not be null");
 213      *     this.baz = Objects.requireNonNull(baz, "baz must not be null");
 214      * }
 215      * </pre></blockquote>
 216      *
 217      * @param obj     the object reference to check for nullity
 218      * @param message detail message to be used in the event that a {@code
 219      *                NullPointerException} is thrown
 220      * @param <T> the type of the reference
 221      * @return {@code obj} if not {@code null}
 222      * @throws NullPointerException if {@code obj} is {@code null}
 223      */
 224     public static <T> T requireNonNull(T obj, String message) {
 225         if (obj == null)
 226             throw new NullPointerException(message);
 227         return obj;
 228     }
 229 
 230     /**
 231      * Returns {@code true} if the provided reference is {@code null} otherwise
 232      * returns {@code false}.
 233      *
 234      * @apiNote This method exists to be used as a
 235      * {@link java.util.function.Predicate}, {@code filter(Objects::isNull)}
 236      *
 237      * @param obj a reference to be checked against {@code null}
 238      * @return {@code true} if the provided reference is {@code null} otherwise
 239      * {@code false}
 240      *
 241      * @see java.util.function.Predicate
 242      * @since 1.8
 243      */
 244     public static boolean isNull(Object obj) {
 245         return obj == null;
 246     }
 247 
 248     /**
 249      * Returns {@code true} if the provided reference is non-{@code null}
 250      * otherwise returns {@code false}.
 251      *
 252      * @apiNote This method exists to be used as a
 253      * {@link java.util.function.Predicate}, {@code filter(Objects::nonNull)}
 254      *
 255      * @param obj a reference to be checked against {@code null}
 256      * @return {@code true} if the provided reference is non-{@code null}
 257      * otherwise {@code false}
 258      *
 259      * @see java.util.function.Predicate
 260      * @since 1.8
 261      */
 262     public static boolean nonNull(Object obj) {
 263         return obj != null;
 264     }
 265 }