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 package java.util.function;
26
27 /**
28 * An operation upon a single operand yielding a result. The operand and the
29 * result are of the same type. This is a specialization of {@code Function} for
30 * the case where the operand and result are of the same type.
31 *
32 * @param <T> the type of operand to {@code apply} and of the result
33 *
34 * @see Function
35 * @since 1.8
36 */
37 @FunctionalInterface
38 public interface UnaryOperator<T> extends Function<T, T> {
39
40 /**
41 * Returns a unary operator that provides its input value as the result.
42 *
43 * @param <T> the type of the input and output objects to the function
44 * @return a unary operator that provides its input value as the result
45 */
46 static <T> UnaryOperator<T> identity() {
47 return t -> t;
48 }
49 }
|
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 package java.util.function;
26
27 /**
28 * Represents an operation on a single operand that produces a result of the
29 * same type as its operand. This is a specialization of {@code Function} for
30 * the case where the operand and result are of the same type.
31 *
32 * <p>This is a <a href="package-summary.html">functional interface</a>
33 * whose functional method is {@link #apply(Object)}.
34 *
35 * @param <T> the type of the operand and result of the operator
36 *
37 * @see Function
38 * @since 1.8
39 */
40 @FunctionalInterface
41 public interface UnaryOperator<T> extends Function<T, T> {
42
43 /**
44 * Returns a unary operator that always returns its input argument.
45 *
46 * @param <T> the type of the input and output of the operator
47 * @return a unary operator that always returns its input argument
48 */
49 static <T> UnaryOperator<T> identity() {
50 return t -> t;
51 }
52 }
|