8 * particular file as subject to the "Classpath" exception as provided
9 * by Oracle in the LICENSE file that accompanied this code.
10 *
11 * This code is distributed in the hope that it will be useful, but WITHOUT
12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
14 * version 2 for more details (a copy is included in the LICENSE file that
15 * accompanied this code).
16 *
17 * You should have received a copy of the GNU General Public License version
18 * 2 along with this work; if not, write to the Free Software Foundation,
19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
20 *
21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
22 * or visit www.oracle.com if you need additional information or have any
23 * questions.
24 */
25
26 package java.util;
27
28 import jdk.internal.util.Preconditions;
29 import jdk.internal.vm.annotation.ForceInline;
30
31 import java.util.function.Supplier;
32
33 /**
34 * This class consists of {@code static} utility methods for operating
35 * on objects, or checking certain conditions before operation. These utilities
36 * include {@code null}-safe or {@code null}-tolerant methods for computing the
37 * hash code of an object, returning a string for an object, comparing two
38 * objects, and checking if indexes or sub-range values are out of bounds.
39 *
40 * @since 1.7
41 */
42 public final class Objects {
43 private Objects() {
44 throw new AssertionError("No java.util.Objects instances for you!");
45 }
46
47 /**
48 * {@return {@code true} if the arguments are equal to each other
49 * and {@code false} otherwise}
160 *
161 * @implNote
162 * This method constructs a string for an object without calling
163 * any overridable methods of the object.
164 *
165 * @implSpec
166 * The method returns a string equivalent to:<br>
167 * {@code o.getClass().getName() + "@" + Integer.toHexString(System.identityHashCode(o))}
168 *
169 * @param o an object
170 * @throws NullPointerException if the argument is null
171 * @see Object#toString
172 * @see System#identityHashCode(Object)
173 * @since 19
174 */
175 public static String toIdentityString(Object o) {
176 requireNonNull(o);
177 return o.getClass().getName() + "@" + Integer.toHexString(System.identityHashCode(o));
178 }
179
180 /**
181 * {@return 0 if the arguments are identical and {@code
182 * c.compare(a, b)} otherwise}
183 * Consequently, if both arguments are {@code null} 0
184 * is returned.
185 *
186 * <p>Note that if one of the arguments is {@code null}, a {@code
187 * NullPointerException} may or may not be thrown depending on
188 * what ordering policy, if any, the {@link Comparator Comparator}
189 * chooses to have for {@code null} values.
190 *
191 * @param <T> the type of the objects being compared
192 * @param a an object
193 * @param b an object to be compared with {@code a}
194 * @param c the {@code Comparator} to compare the first two arguments
195 * @see Comparable
196 * @see Comparator
197 */
198 public static <T> int compare(T a, T b, Comparator<? super T> c) {
199 return (a == b) ? 0 : c.compare(a, b);
400 * inequalities is true:
401 * <ul>
402 * <li>{@code fromIndex < 0}</li>
403 * <li>{@code size < 0}</li>
404 * <li>{@code fromIndex + size > length}, taking into account integer overflow</li>
405 * <li>{@code length < 0}, which is implied from the former inequalities</li>
406 * </ul>
407 *
408 * @param fromIndex the lower-bound (inclusive) of the sub-interval
409 * @param size the size of the sub-range
410 * @param length the upper-bound (exclusive) of the range
411 * @return {@code fromIndex} if the sub-range within bounds of the range
412 * @throws IndexOutOfBoundsException if the sub-range is out of bounds
413 * @since 9
414 */
415 public static
416 int checkFromIndexSize(int fromIndex, int size, int length) {
417 return Preconditions.checkFromIndexSize(fromIndex, size, length, null);
418 }
419
420 /**
421 * Checks if the {@code index} is within the bounds of the range from
422 * {@code 0} (inclusive) to {@code length} (exclusive).
423 *
424 * <p>The {@code index} is defined to be out of bounds if any of the
425 * following inequalities is true:
426 * <ul>
427 * <li>{@code index < 0}</li>
428 * <li>{@code index >= length}</li>
429 * <li>{@code length < 0}, which is implied from the former inequalities</li>
430 * </ul>
431 *
432 * @param index the index
433 * @param length the upper-bound (exclusive) of the range
434 * @return {@code index} if it is within bounds of the range
435 * @throws IndexOutOfBoundsException if the {@code index} is out of bounds
436 * @since 16
437 */
438 @ForceInline
439 public static
|
8 * particular file as subject to the "Classpath" exception as provided
9 * by Oracle in the LICENSE file that accompanied this code.
10 *
11 * This code is distributed in the hope that it will be useful, but WITHOUT
12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
14 * version 2 for more details (a copy is included in the LICENSE file that
15 * accompanied this code).
16 *
17 * You should have received a copy of the GNU General Public License version
18 * 2 along with this work; if not, write to the Free Software Foundation,
19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
20 *
21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
22 * or visit www.oracle.com if you need additional information or have any
23 * questions.
24 */
25
26 package java.util;
27
28 import jdk.internal.javac.PreviewFeature;
29 import jdk.internal.util.Preconditions;
30 import jdk.internal.vm.annotation.ForceInline;
31 import jdk.internal.misc.Unsafe;
32
33 import java.util.function.Supplier;
34
35 /**
36 * This class consists of {@code static} utility methods for operating
37 * on objects, or checking certain conditions before operation. These utilities
38 * include {@code null}-safe or {@code null}-tolerant methods for computing the
39 * hash code of an object, returning a string for an object, comparing two
40 * objects, and checking if indexes or sub-range values are out of bounds.
41 *
42 * @since 1.7
43 */
44 public final class Objects {
45 private Objects() {
46 throw new AssertionError("No java.util.Objects instances for you!");
47 }
48
49 /**
50 * {@return {@code true} if the arguments are equal to each other
51 * and {@code false} otherwise}
162 *
163 * @implNote
164 * This method constructs a string for an object without calling
165 * any overridable methods of the object.
166 *
167 * @implSpec
168 * The method returns a string equivalent to:<br>
169 * {@code o.getClass().getName() + "@" + Integer.toHexString(System.identityHashCode(o))}
170 *
171 * @param o an object
172 * @throws NullPointerException if the argument is null
173 * @see Object#toString
174 * @see System#identityHashCode(Object)
175 * @since 19
176 */
177 public static String toIdentityString(Object o) {
178 requireNonNull(o);
179 return o.getClass().getName() + "@" + Integer.toHexString(System.identityHashCode(o));
180 }
181
182 /**
183 * {@return {@code true} if the specified object reference is an identity object,
184 * otherwise {@code false}}
185 *
186 * @param obj an object
187 * @throws NullPointerException if {@code obj} is {@code null}
188 */
189 @PreviewFeature(feature = PreviewFeature.Feature.VALUE_OBJECTS)
190 // @IntrinsicCandidate
191 public static boolean isIdentityObject(Object obj) {
192 requireNonNull(obj);
193 return obj.getClass().isIdentity() || // Before Valhalla all classes are identity classes
194 obj.getClass() == Object.class;
195 }
196
197 /**
198 * Checks that the specified object reference is an identity object.
199 *
200 * @param obj the object reference to check for identity
201 * @param <T> the type of the reference
202 * @return {@code obj} if {@code obj} is an identity object
203 * @throws NullPointerException if {@code obj} is {@code null}
204 * @throws IdentityException if {@code obj} is not an identity object
205 * @since Valhalla
206 */
207 @PreviewFeature(feature = PreviewFeature.Feature.VALUE_OBJECTS)
208 @ForceInline
209 public static <T> T requireIdentity(T obj) {
210 Objects.requireNonNull(obj);
211 if (!isIdentityObject(obj))
212 throw new IdentityException(obj.getClass());
213 return obj;
214 }
215
216 /**
217 * Checks that the specified object reference is an identity object.
218 *
219 * @param obj the object reference to check for identity
220 * @param message detail message to be used in the event that an
221 * {@code IdentityException} is thrown; may be null
222 * @param <T> the type of the reference
223 * @return {@code obj} if {@code obj} is an identity object
224 * @throws NullPointerException if {@code obj} is {@code null}
225 * @throws IdentityException if {@code obj} is not an identity object
226 * @since Valhalla
227 */
228 @PreviewFeature(feature = PreviewFeature.Feature.VALUE_OBJECTS)
229 @ForceInline
230 public static <T> T requireIdentity(T obj, String message) {
231 Objects.requireNonNull(obj);
232 if (!isIdentityObject(obj))
233 throw new IdentityException(message);
234 return obj;
235 }
236
237 /**
238 * Checks that the specified object reference is an identity object.
239 *
240 * @param obj the object reference to check for identity
241 * @param messageSupplier supplier of the detail message to be
242 * used in the event that an {@code IdentityException} is thrown; may be null
243 * @param <T> the type of the reference
244 * @return {@code obj} if {@code obj} is an identity object
245 * @throws NullPointerException if {@code obj} is {@code null}
246 * @throws IdentityException if {@code obj} is not an identity object
247 * @since Valhalla
248 */
249 @PreviewFeature(feature = PreviewFeature.Feature.VALUE_OBJECTS)
250 @ForceInline
251 public static <T> T requireIdentity(T obj, Supplier<String> messageSupplier) {
252 Objects.requireNonNull(obj);
253 if (!isIdentityObject(obj))
254 throw new IdentityException(messageSupplier == null ?
255 null : messageSupplier.get());
256 return obj;
257 }
258
259 /**
260 * {@return {@code true} if the specified object is a {@linkplain Class#isValue value object},
261 * otherwise {@code false}}
262 *
263 * @param obj an object
264 * @throws NullPointerException if {@code obj} is {@code null}
265 */
266 @PreviewFeature(feature = PreviewFeature.Feature.VALUE_OBJECTS)
267 // @IntrinsicCandidate
268 public static boolean isValueObject(Object obj) {
269 requireNonNull(obj, "obj");
270 return obj.getClass().isValue();
271 }
272
273 /**
274 * {@return 0 if the arguments are identical and {@code
275 * c.compare(a, b)} otherwise}
276 * Consequently, if both arguments are {@code null} 0
277 * is returned.
278 *
279 * <p>Note that if one of the arguments is {@code null}, a {@code
280 * NullPointerException} may or may not be thrown depending on
281 * what ordering policy, if any, the {@link Comparator Comparator}
282 * chooses to have for {@code null} values.
283 *
284 * @param <T> the type of the objects being compared
285 * @param a an object
286 * @param b an object to be compared with {@code a}
287 * @param c the {@code Comparator} to compare the first two arguments
288 * @see Comparable
289 * @see Comparator
290 */
291 public static <T> int compare(T a, T b, Comparator<? super T> c) {
292 return (a == b) ? 0 : c.compare(a, b);
493 * inequalities is true:
494 * <ul>
495 * <li>{@code fromIndex < 0}</li>
496 * <li>{@code size < 0}</li>
497 * <li>{@code fromIndex + size > length}, taking into account integer overflow</li>
498 * <li>{@code length < 0}, which is implied from the former inequalities</li>
499 * </ul>
500 *
501 * @param fromIndex the lower-bound (inclusive) of the sub-interval
502 * @param size the size of the sub-range
503 * @param length the upper-bound (exclusive) of the range
504 * @return {@code fromIndex} if the sub-range within bounds of the range
505 * @throws IndexOutOfBoundsException if the sub-range is out of bounds
506 * @since 9
507 */
508 public static
509 int checkFromIndexSize(int fromIndex, int size, int length) {
510 return Preconditions.checkFromIndexSize(fromIndex, size, length, null);
511 }
512
513 /**
514 * Return the size of the object in the heap.
515 *
516 * @param o an object
517 * @return the objects's size
518 * @since Valhalla
519 */
520 public static long getObjectSize(Object o) {
521 return Unsafe.getUnsafe().getObjectSize(o);
522 }
523
524 /**
525 * Checks if the {@code index} is within the bounds of the range from
526 * {@code 0} (inclusive) to {@code length} (exclusive).
527 *
528 * <p>The {@code index} is defined to be out of bounds if any of the
529 * following inequalities is true:
530 * <ul>
531 * <li>{@code index < 0}</li>
532 * <li>{@code index >= length}</li>
533 * <li>{@code length < 0}, which is implied from the former inequalities</li>
534 * </ul>
535 *
536 * @param index the index
537 * @param length the upper-bound (exclusive) of the range
538 * @return {@code index} if it is within bounds of the range
539 * @throws IndexOutOfBoundsException if the {@code index} is out of bounds
540 * @since 16
541 */
542 @ForceInline
543 public static
|