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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

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 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.  Oracle designates this

 * particular file as subject to the "Classpath" exception as provided

 * by Oracle in the LICENSE file that accompanied this code.

 *

 * This code is distributed in the hope that it will be useful, but WITHOUT

 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

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 *

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package java.util.function;

/**

 * Represents an operation on a single operand that produces a result of the

 * same type as its operand.  This is a specialization of {@code Function} for

 * the case where the operand and result are of the same type.

 *

 * <p>This is a <a href="package-summary.html">functional interface</a>

 * whose functional method is {@link #apply(Object)}.

 *

 * @param <T> the type of the operand and result of the operator

 *

 * @see Function

 * @since 1.8

 */

@FunctionalInterface

public interface UnaryOperator<T> extends Function<T, T> {

    /**

     * Returns a unary operator that always returns its input argument.

     *

     * @param <T> the type of the input and output of the operator

     * @return a unary operator that always returns its input argument

     */

    static <T> UnaryOperator<T> identity() {

        return t -> t;

    }

}