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src/java.base/share/classes/java/util/function/UnaryOperator.java

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   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.  Oracle designates this
   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 }


   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.  Oracle designates this
   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 javany.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<any 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 }
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